| blob | 26b821d38d108cac66b3fb2fd601ca9cd1473e15 |
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- F R E E Z E --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1992-2009, Free Software Foundation, Inc. --
10 -- --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. --
17 -- --
18 -- You should have received a copy of the GNU General Public License along --
19 -- with this program; see file COPYING3. If not see --
20 -- <http://www.gnu.org/licenses/>. --
21 -- --
22 -- GNAT was originally developed by the GNAT team at New York University. --
23 -- Extensive contributions were provided by Ada Core Technologies Inc. --
24 -- --
25 ------------------------------------------------------------------------------
68 -----------------------
69 -- Local Subprograms --
70 -----------------------
73 -- Typ is a type that is being frozen. If no size clause is given,
74 -- but a default Esize has been computed, then this default Esize is
75 -- adjusted up if necessary to be consistent with a given alignment,
76 -- but never to a value greater than Long_Long_Integer'Size. This
77 -- is used for all discrete types and for fixed-point types.
79 procedure Build_And_Analyze_Renamed_Body
83 -- Build body for a renaming declaration, insert in tree and analyze
86 -- Apply legality checks to address clauses for object declarations,
87 -- at the point the object is frozen.
90 -- E is a base type. If E is tagged or has a component that is aliased
91 -- or tagged or contains something this is aliased or tagged, set
92 -- Strict_Alignment.
96 -- If E is a fixed-point or discrete type, then all the necessary work
97 -- to freeze it is completed except for possible setting of the flag
98 -- Is_Unsigned_Type, which is done by this procedure. The call has no
99 -- effect if the entity E is not a discrete or fixed-point type.
101 procedure Freeze_And_Append
105 -- Freezes Ent using Freeze_Entity, and appends the resulting list of
106 -- nodes to Result, modifying Result from No_List if necessary.
109 -- Freeze enumeration type. The Esize field is set as processing
110 -- proceeds (i.e. set by default when the type is declared and then
111 -- adjusted by rep clauses. What this procedure does is to make sure
112 -- that if a foreign convention is specified, and no specific size
113 -- is given, then the size must be at least Integer'Size.
116 -- If an object is frozen which has Is_Statically_Allocated set, then
117 -- all referenced types must also be marked with this flag. This routine
118 -- is in charge of meeting this requirement for the object entity E.
121 -- Perform freezing actions for a subprogram (create extra formals,
122 -- and set proper default mechanism values). Note that this routine
123 -- is not called for internal subprograms, for which neither of these
124 -- actions is needed (or desirable, we do not want for example to have
125 -- these extra formals present in initialization procedures, where they
126 -- would serve no purpose). In this call E is either a subprogram or
127 -- a subprogram type (i.e. an access to a subprogram).
130 -- True if T is not private and has no private components, or has a full
131 -- view. Used to determine whether the designated type of an access type
132 -- should be frozen when the access type is frozen. This is done when an
133 -- allocator is frozen, or an expression that may involve attributes of
134 -- the designated type. Otherwise freezing the access type does not freeze
135 -- the designated type.
137 procedure Process_Default_Expressions
140 -- This procedure is called for each subprogram to complete processing
141 -- of default expressions at the point where all types are known to be
142 -- frozen. The expressions must be analyzed in full, to make sure that
143 -- all error processing is done (they have only been pre-analyzed). If
144 -- the expression is not an entity or literal, its analysis may generate
145 -- code which must not be executed. In that case we build a function
146 -- body to hold that code. This wrapper function serves no other purpose
147 -- (it used to be called to evaluate the default, but now the default is
148 -- inlined at each point of call).
151 -- Typ is a record or array type that is being frozen. This routine
152 -- sets the default component alignment from the scope stack values
153 -- if the alignment is otherwise not specified.
156 -- As each entity is frozen, this routine is called to deal with the
157 -- setting of Debug_Info_Needed for the entity. This flag is set if
158 -- the entity comes from source, or if we are in Debug_Generated_Code
159 -- mode or if the -gnatdV debug flag is set. However, it never sets
160 -- the flag if Debug_Info_Off is set. This procedure also ensures that
161 -- subsidiary entities have the flag set as required.
164 -- T is a type of a component that we know to be an Itype.
165 -- We don't want this to have a Freeze_Node, so ensure it doesn't.
166 -- Do the same for any Full_View or Corresponding_Record_Type.
168 procedure Warn_Overlay
172 -- Expr is the expression for an address clause for entity Nam whose type
173 -- is Typ. If Typ has a default initialization, and there is no explicit
174 -- initialization in the source declaration, check whether the address
175 -- clause might cause overlaying of an entity, and emit a warning on the
176 -- side effect that the initialization will cause.
178 -------------------------------
179 -- Adjust_Esize_For_Alignment --
180 -------------------------------
185 begin
191 then
197 ------------------------------------
198 -- Build_And_Analyze_Renamed_Body --
199 ------------------------------------
201 procedure Build_And_Analyze_Renamed_Body
205 is
207 begin
214 ------------------------
215 -- Build_Renamed_Body --
216 ------------------------
218 function Build_Renamed_Body
221 is
223 -- We use for the source location of the renamed body, the location
224 -- of the spec entity. It might seem more natural to use the location
225 -- of the renaming declaration itself, but that would be wrong, since
226 -- then the body we create would look as though it was created far
227 -- too late, and this could cause problems with elaboration order
228 -- analysis, particularly in connection with instantiations.
243 -- If the renamed entity is a primitive operation given in prefix form,
244 -- the prefix is the target object and it has to be added as the first
245 -- actual in the generated call.
247 begin
248 -- Determine the entity being renamed, which is the target of the call
249 -- statement. If the name is an explicit dereference, this is a renaming
250 -- of a subprogram type rather than a subprogram. The name itself is
251 -- fully analyzed.
262 else
269 else
275 -- If the renamed entity is a predefined operator, retain full name
276 -- to ensure its visibility.
280 then
282 else
286 else
289 and then
292 then
294 -- Retrieve the target object, to be added as a first actual
295 -- in the call.
300 else
304 -- The original name may have been overloaded, but
305 -- is fully resolved now.
310 -- For simple renamings, subsequent calls can be expanded directly as
311 -- called to the renamed entity. The body must be generated in any case
312 -- for calls they may appear elsewhere.
317 then
321 -- The body generated for this renaming is an internal artifact, and
322 -- does not constitute a freeze point for the called entity.
329 declare
333 begin
335 -- The controlling formal may be an access parameter, or the
336 -- actual may be an access value, so adjust accordingly.
340 then
341 Actuals := New_List
346 then
347 Actuals := New_List
351 else
359 else
370 -- If the renamed entity is an entry, inherit its profile. For other
371 -- renamings as bodies, both profiles must be subtype conformant, so it
372 -- is not necessary to replace the profile given in the declaration.
373 -- However, default values that are aggregates are rewritten when
374 -- partially analyzed, so we recover the original aggregate to insure
375 -- that subsequent conformity checking works. Similarly, if the default
376 -- expression was constant-folded, recover the original expression.
388 N_Access_Definition
389 then
397 then
408 -- If the renamed entity is a function, the generated body contains a
409 -- return statement. Otherwise, build a procedure call. If the entity is
410 -- an entry, subsequent analysis of the call will transform it into the
411 -- proper entry or protected operation call. If the renamed entity is
412 -- a character literal, return it directly.
418 then
419 Call_Node :=
421 Expression =>
427 Call_Node :=
432 Call_Node :=
436 else
437 Call_Node :=
443 -- Create entities for subprogram body and formals
457 Body_Node :=
461 Handled_Statement_Sequence =>
471 -- Link the body to the entity whose declaration it completes. If
472 -- the body is analyzed when the renamed entity is frozen, it may
473 -- be necessary to restore the proper scope (see package Exp_Ch13).
477 then
479 else
486 --------------------------
487 -- Check_Address_Clause --
488 --------------------------
496 begin
500 -- If we have no initialization of any kind, then we don't need to
501 -- place any restrictions on the address clause, because the object
502 -- will be elaborated after the address clause is evaluated. This
503 -- happens if the declaration has no initial expression, or the type
504 -- has no implicit initialization, or the object is imported.
506 -- The same holds for all initialized scalar types and all access
507 -- types. Packed bit arrays of size up to 64 are represented using a
508 -- modular type with an initialization (to zero) and can be processed
509 -- like other initialized scalar types.
511 -- If the type is controlled, code to attach the object to a
512 -- finalization chain is generated at the point of declaration,
513 -- and therefore the elaboration of the object cannot be delayed:
514 -- the address expression must be a constant.
518 and then
522 or else
526 or else
529 or else
531 and then
533 then
536 -- Otherwise, we require the address clause to be constant because
537 -- the call to the initialization procedure (or the attach code) has
538 -- to happen at the point of the declaration.
539 -- Actually the IP call has been moved to the freeze actions
540 -- anyway, so maybe we can relax this restriction???
542 else
545 -- Has_Delayed_Freeze was set on E when the address clause was
546 -- analyzed. Reset the flag now unless freeze actions were
547 -- attached to it in the mean time.
556 then
562 -----------------------------
563 -- Check_Compile_Time_Size --
564 -----------------------------
569 -- Sets the compile time known size (32 bits or less) in the Esize
570 -- field, of T checking for a size clause that was given which attempts
571 -- to give a smaller size.
574 -- Recursive function that does all the work
577 -- If T is a constrained subtype, its size is not known if any of its
578 -- discriminant constraints is not static and it is not a null record.
579 -- The test is conservative and doesn't check that the components are
580 -- in fact constrained by non-static discriminant values. Could be made
581 -- more precise ???
583 --------------------
584 -- Set_Small_Size --
585 --------------------
588 begin
595 Error_Msg_NE
603 -- Set sizes if not set already
605 else
616 ----------------
617 -- Size_Known --
618 ----------------
627 begin
631 -- Always True for scalar types. This is true even for generic formal
632 -- scalar types. We used to return False in the latter case, but the
633 -- size is known at compile time, even in the template, we just do
634 -- not know the exact size but that's not the point of this routine.
638 then
641 -- Array types
645 -- String literals always have known size, and we can set it
652 -- Unconstrained types never have known at compile time size
657 -- Don't do any recursion on type with error posted, since we may
658 -- have a malformed type that leads us into a loop.
663 -- Otherwise if component size unknown, then array size unknown
669 -- Check for all indexes static, and also compute possible size
670 -- (in case it is less than 32 and may be packable).
672 declare
676 begin
685 else
693 then
696 else
701 else
713 -- Access types always have known at compile time sizes
718 -- For non-generic private types, go to underlying type if present
723 then
724 -- Don't do any recursion on type with error posted, since we may
725 -- have a malformed type that leads us into a loop.
729 else
733 -- Record types
737 -- A class-wide type is never considered to have a known size
742 -- A subtype of a variant record must not have non-static
743 -- discriminanted components.
747 then
750 -- Don't do any recursion on type with error posted, since we may
751 -- have a malformed type that leads us into a loop.
757 -- Now look at the components of the record
759 declare
760 -- The following two variables are used to keep track of the
761 -- size of packed records if we can tell the size of the packed
762 -- record in the front end. Packed_Size_Known is True if so far
763 -- we can figure out the size. It is initialized to True for a
764 -- packed record, unless the record has discriminants. The
765 -- reason we eliminate the discriminated case is that we don't
766 -- know the way the back end lays out discriminated packed
767 -- records. If Packed_Size_Known is True, then Packed_Size is
768 -- the size in bits so far.
776 begin
777 -- Test for variant part present
783 N_Record_Definition
787 then
788 -- If variant part is present, and type is unconstrained,
789 -- then we must have defaulted discriminants, or a size
790 -- clause must be present for the type, or else the size
791 -- is definitely not known at compile time.
794 and then
795 No (Discriminant_Default_Value
798 then
803 -- Loop through components
809 -- We do not know the packed size if there is a component
810 -- clause present (we possibly could, but this would only
811 -- help in the case of a record with partial rep clauses.
812 -- That's because in the case of full rep clauses, the
813 -- size gets figured out anyway by a different circuit).
819 -- We need to identify a component that is an array where
820 -- the index type is an enumeration type with non-standard
821 -- representation, and some bound of the type depends on a
822 -- discriminant.
824 -- This is because gigi computes the size by doing a
825 -- substitution of the appropriate discriminant value in
826 -- the size expression for the base type, and gigi is not
827 -- clever enough to evaluate the resulting expression (which
828 -- involves a call to rep_to_pos) at compile time.
830 -- It would be nice if gigi would either recognize that
831 -- this expression can be computed at compile time, or
832 -- alternatively figured out the size from the subtype
833 -- directly, where all the information is at hand ???
837 then
838 declare
846 begin
853 then
859 then
864 then
874 -- Clearly size of record is not known if the size of one of
875 -- the components is not known.
881 -- Accumulate packed size if possible
885 -- We can only deal with elementary types, since for
886 -- non-elementary components, alignment enters into the
887 -- picture, and we don't know enough to handle proper
888 -- alignment in this context. Packed arrays count as
889 -- elementary if the representation is a modular type.
894 and then Is_Modular_Integer_Type
896 then
897 -- If RM_Size is known and static, then we can
898 -- keep accumulating the packed size.
902 -- A little glitch, to be removed sometime ???
903 -- gigi does not understand zero sizes yet.
908 -- Normal case where we can keep accumulating the
909 -- packed array size.
911 else
915 -- If we have a field whose RM_Size is not known then
916 -- we can't figure out the packed size here.
918 else
922 -- If we have a non-elementary type we can't figure out
923 -- the packed array size (alignment issues).
925 else
940 -- All other cases, size not known at compile time
942 else
947 -------------------------------------
948 -- Static_Discriminated_Components --
949 -------------------------------------
951 function Static_Discriminated_Components
953 is
956 begin
960 then
974 -- Start of processing for Check_Compile_Time_Size
976 begin
980 -----------------------------
981 -- Check_Debug_Info_Needed --
982 -----------------------------
985 begin
990 or else Debug_Generated_Code
991 or else Debug_Flag_VV
993 then
998 ----------------------------
999 -- Check_Strict_Alignment --
1000 ----------------------------
1005 begin
1024 then
1034 -------------------------
1035 -- Check_Unsigned_Type --
1036 -------------------------
1043 begin
1048 -- Do not attempt to analyze case where range was in error
1054 -- The situation that is non trivial is something like
1056 -- subtype x1 is integer range -10 .. +10;
1057 -- subtype x2 is x1 range 0 .. V1;
1058 -- subtype x3 is x2 range V2 .. V3;
1059 -- subtype x4 is x3 range V4 .. V5;
1061 -- where Vn are variables. Here the base type is signed, but we still
1062 -- know that x4 is unsigned because of the lower bound of x2.
1064 -- The only way to deal with this is to look up the ancestor chain
1067 loop
1082 else
1085 -- If no ancestor had a static lower bound, go to base type
1089 -- Note: the reason we still check for a compile time known
1090 -- value for the base type is that at least in the case of
1091 -- generic formals, we can have bounds that fail this test,
1092 -- and there may be other cases in error situations.
1104 then
1114 -------------------------
1115 -- Is_Atomic_Aggregate --
1116 -------------------------
1118 function Is_Atomic_Aggregate
1121 is
1127 begin
1130 -- Array may be qualified, so find outer context
1138 then
1139 Temp :=
1143 New_N :=
1154 else
1159 ----------------
1160 -- Freeze_All --
1161 ----------------
1163 -- Note: the easy coding for this procedure would be to just build a
1164 -- single list of freeze nodes and then insert them and analyze them
1165 -- all at once. This won't work, because the analysis of earlier freeze
1166 -- nodes may recursively freeze types which would otherwise appear later
1167 -- on in the freeze list. So we must analyze and expand the freeze nodes
1168 -- as they are generated.
1176 -- This is the internal recursive routine that does freezing of entities
1177 -- (but NOT the analysis of default expressions, which should not be
1178 -- recursive, we don't want to analyze those till we are sure that ALL
1179 -- the types are frozen).
1181 --------------------
1182 -- Freeze_All_Ent --
1183 --------------------
1185 procedure Freeze_All_Ent
1188 is
1194 -- If freeze nodes are present, insert and analyze, and reset cursor
1195 -- for next insertion.
1197 -------------------
1198 -- Process_Flist --
1199 -------------------
1202 begin
1209 else
1215 -- Start or processing for Freeze_All_Ent
1217 begin
1221 -- If the entity is an inner package which is not a package
1222 -- renaming, then its entities must be frozen at this point. Note
1223 -- that such entities do NOT get frozen at the end of the nested
1224 -- package itself (only library packages freeze).
1226 -- Same is true for task declarations, where anonymous records
1227 -- created for entry parameters must be frozen.
1233 then
1243 and then
1245 or else
1247 then
1250 End_Scope;
1252 -- For a derived tagged type, we must ensure that all the
1253 -- primitive operations of the parent have been frozen, so that
1254 -- their addresses will be in the parent's dispatch table at the
1255 -- point it is inherited.
1261 then
1262 declare
1269 begin
1277 then
1279 Process_Flist;
1289 Process_Flist;
1292 -- If an incomplete type is still not frozen, this may be a
1293 -- premature freezing because of a body declaration that follows.
1294 -- Indicate where the freezing took place.
1296 -- If the freezing is caused by the end of the current declarative
1297 -- part, it is a Taft Amendment type, and there is no error.
1301 then
1302 declare
1305 begin
1312 and then
1314 then
1316 Error_Msg_NE
1327 -- Start of processing for Freeze_All
1329 begin
1332 -- Now that all types are frozen, we can deal with default expressions
1333 -- that require us to build a default expression functions. This is the
1334 -- point at which such functions are constructed (after all types that
1335 -- might be used in such expressions have been frozen).
1337 -- We also add finalization chains to access types whose designated
1338 -- types are controlled. This is normally done when freezing the type,
1339 -- but this misses recursive type definitions where the later members
1340 -- of the recursion introduce controlled components.
1342 -- Loop through entities
1360 and then
1362 = N_Subprogram_Renaming_Declaration
1363 then
1364 Build_And_Analyze_Renamed_Body
1370 and then
1372 or else
1374 then
1375 declare
1377 begin
1384 then
1397 then
1405 -----------------------
1406 -- Freeze_And_Append --
1407 -----------------------
1409 procedure Freeze_And_Append
1413 is
1415 begin
1419 else
1425 -------------------
1426 -- Freeze_Before --
1427 -------------------
1431 begin
1437 -------------------
1438 -- Freeze_Entity --
1439 -------------------
1451 -- This flag gets set to true for a variable with default initialization
1454 -- Check that an Access or Unchecked_Access attribute with a prefix
1455 -- which is the current instance type can only be applied when the type
1456 -- is limited.
1459 -- Give warning for modulus of 8, 16, 32, or 64 given as an explicit
1460 -- integer literal without an explicit corresponding size clause. The
1461 -- caller has checked that Utype is a modular integer type.
1464 -- If Loc is a freeze_entity that appears after the last declaration
1465 -- in the scope, inhibit error messages on late completion.
1468 -- Freeze each component, handle some representation clauses, and freeze
1469 -- primitive operations if this is a tagged type.
1471 ----------------------------
1472 -- After_Last_Declaration --
1473 ----------------------------
1477 begin
1483 else
1486 else
1491 ----------------------------
1492 -- Check_Current_Instance --
1493 ----------------------------
1503 -- Process routine to apply check to given node
1505 -------------
1506 -- Process --
1507 -------------
1510 begin
1514 or else
1519 then
1520 Error_Msg_N
1523 else
1533 -- Start of processing for Check_Current_Instance
1535 begin
1536 -- In Ada95, the (imprecise) rule is that the current instance of a
1537 -- limited type is aliased. In Ada2005, limitedness must be explicit:
1538 -- either a tagged type, or a limited record.
1542 then
1547 then
1550 else
1555 ------------------------------
1556 -- Check_Suspicious_Modulus --
1557 ------------------------------
1562 begin
1564 declare
1566 begin
1568 declare
1571 begin
1573 declare
1577 begin
1578 -- First case, modulus and size are the same. This
1579 -- happens if you have something like mod 32, with
1580 -- an explicit size of 32, this is for sure a case
1581 -- where the warning is given, since it is seems
1582 -- very unlikely that someone would want e.g. a
1583 -- five bit type stored in 32 bits. It is much
1584 -- more likely they wanted a 32-bit type.
1589 -- Second case, the modulus is 32 or 64 and no
1590 -- size clause is present. This is a less clear
1591 -- case for giving the warning, but in the case
1592 -- of 32/64 (5-bit or 6-bit types) these seem rare
1593 -- enough that it is a likely error (and in any
1594 -- case using 2**5 or 2**6 in these cases seems
1595 -- clearer. We don't include 8 or 16 here, simply
1596 -- because in practice 3-bit and 4-bit types are
1597 -- more common and too many false positives if
1598 -- we warn in these cases.
1602 then
1605 -- No warning needed
1607 else
1611 -- If we fall through, give warning
1614 Error_Msg_N
1616 Modulus);
1625 ------------------------
1626 -- Freeze_Record_Type --
1627 ------------------------
1639 -- Set True if we find at least one component with no component
1640 -- clause (used to warn about useless Pack pragmas).
1643 -- Set True if we find at least one component with a component
1644 -- clause (used to warn about useless Bit_Order pragmas, and also
1645 -- to detect cases where Implicit_Packing may have an effect).
1648 -- Set False if we encounter a component of a non-scalar type
1652 -- Accumulates total RM_Size values and total Esize values of all
1653 -- scalar components. Used for processing of Implicit_Packing.
1656 -- If N is an allocator, possibly wrapped in one or more level of
1657 -- qualified expression(s), return the inner allocator node, else
1658 -- return Empty.
1661 -- If the component subtype is an access to a constrained subtype of
1662 -- an already frozen type, make the subtype frozen as well. It might
1663 -- otherwise be frozen in the wrong scope, and a freeze node on
1664 -- subtype has no effect. Similarly, if the component subtype is a
1665 -- regular (not protected) access to subprogram, set the anonymous
1666 -- subprogram type to frozen as well, to prevent an out-of-scope
1667 -- freeze node at some eventual point of call. Protected operations
1668 -- are handled elsewhere.
1670 ---------------------
1671 -- Check_Allocator --
1672 ---------------------
1676 begin
1678 loop
1683 else
1689 -----------------
1690 -- Check_Itype --
1691 -----------------
1696 begin
1699 then
1702 -- In addition, add an Itype_Reference to ensure that the
1703 -- access subtype is elaborated early enough. This cannot be
1704 -- done if the subtype may depend on discriminants.
1709 then
1715 else
1722 then
1727 -- Start of processing for Freeze_Record_Type
1729 begin
1730 -- If this is a subtype of a controlled type, declared without a
1731 -- constraint, the _controller may not appear in the component list
1732 -- if the parent was not frozen at the point of subtype declaration.
1733 -- Inherit the _controller component now.
1737 then
1740 then
1743 -- If this is an internal type without a declaration, as for
1744 -- record component, the base type may not yet be frozen, and its
1745 -- controller has not been created. Add an explicit freeze node
1746 -- for the itype, so it will be frozen after the base type. This
1747 -- freeze node is used to communicate with the expander, in order
1748 -- to create the controller for the enclosing record, and it is
1749 -- deleted afterwards (see exp_ch3). It must not be created when
1750 -- expansion is off, because it might appear in the wrong context
1751 -- for the back end.
1755 and then
1757 N_Component_Declaration
1758 and then Expander_Active
1759 then
1764 -- Freeze components and embedded subtypes
1770 -- First handle the (real) component case
1774 then
1775 declare
1778 begin
1779 -- Freezing a record type freezes the type of each of its
1780 -- components. However, if the type of the component is
1781 -- part of this record, we do not want or need a separate
1782 -- Freeze_Node. Note that Is_Itype is wrong because that's
1783 -- also set in private type cases. We also can't check for
1784 -- the Scope being exactly Rec because of private types and
1785 -- record extensions.
1790 then
1796 -- Check for error of component clause given for variable
1797 -- sized type. We have to delay this test till this point,
1798 -- since the component type has to be frozen for us to know
1799 -- if it is variable length. We omit this test in a generic
1800 -- context, it will be applied at instantiation time.
1808 elsif not
1809 Size_Known_At_Compile_Time
1811 then
1812 Error_Msg_N
1817 else
1821 -- Case of component requires byte alignment
1825 -- Set the enclosing record to also require byte align
1829 -- Check for component clause that is inconsistent with
1830 -- the required byte boundary alignment.
1835 then
1836 Error_Msg_N
1842 -- If component clause is present, then deal with the non-
1843 -- default bit order case for Ada 95 mode. The required
1844 -- processing for Ada 2005 mode is handled separately after
1845 -- processing all components.
1847 -- We only do this processing for the base type, and in
1848 -- fact that's important, since otherwise if there are
1849 -- record subtypes, we could reverse the bits once for
1850 -- each subtype, which would be incorrect.
1856 then
1857 declare
1870 begin
1871 -- Cases where field goes over storage unit boundary
1875 -- Allow multi-byte field but generate warning
1879 then
1880 Error_Msg_N
1885 Error_Msg_N
1888 else
1889 Error_Msg_N
1894 -- Do not allow non-contiguous field
1896 else
1897 Error_Msg_N
1900 Error_Msg_N
1903 Error_Msg_N
1908 -- Case where field fits in one storage unit
1910 else
1911 -- Give warning if suspicious component clause
1914 and then Warn_On_Reverse_Bit_Order
1915 then
1916 Error_Msg_N
1919 Error_Msg_Uint_1 :=
1921 System_Storage_Unit;
1922 Error_Msg_N
1927 -- Here is where we fix up the Component_Bit_Offset
1928 -- value to account for the reverse bit order.
1929 -- Some examples of what needs to be done are:
1931 -- First_Bit .. Last_Bit Component_Bit_Offset
1932 -- old new old new
1934 -- 0 .. 0 7 .. 7 0 7
1935 -- 0 .. 1 6 .. 7 0 6
1936 -- 0 .. 2 5 .. 7 0 5
1937 -- 0 .. 7 0 .. 7 0 4
1939 -- 1 .. 1 6 .. 6 1 6
1940 -- 1 .. 4 3 .. 6 1 3
1941 -- 4 .. 7 0 .. 3 4 0
1943 -- The general rule is that the first bit is
1944 -- is obtained by subtracting the old ending bit
1945 -- from storage_unit - 1.
1947 Set_Component_Bit_Offset
1953 Set_Normalized_First_Bit
1956 System_Storage_Unit);
1963 -- Gather data for possible Implicit_Packing later
1967 else
1968 Scalar_Component_Total_RM_Size :=
1970 Scalar_Component_Total_Esize :=
1974 -- If the component is an Itype with Delayed_Freeze and is either
1975 -- a record or array subtype and its base type has not yet been
1976 -- frozen, we must remove this from the entity list of this
1977 -- record and put it on the entity list of the scope of its base
1978 -- type. Note that we know that this is not the type of a
1979 -- component since we cleared Has_Delayed_Freeze for it in the
1980 -- previous loop. Thus this must be the Designated_Type of an
1981 -- access type, which is the type of a component.
1989 then
1990 declare
1994 begin
1995 -- We have a pretty bad kludge here. Suppose Rec is subtype
1996 -- being defined in a subprogram that's created as part of
1997 -- the freezing of Rec'Base. In that case, we know that
1998 -- Comp'Base must have already been frozen by the time we
1999 -- get to elaborate this because Gigi doesn't elaborate any
2000 -- bodies until it has elaborated all of the declarative
2001 -- part. But Is_Frozen will not be set at this point because
2002 -- we are processing code in lexical order.
2004 -- We detect this case by going up the Scope chain of Rec
2005 -- and seeing if we have a subprogram scope before reaching
2006 -- the top of the scope chain or that of Comp'Base. If we
2007 -- do, then mark that Comp'Base will actually be frozen. If
2008 -- so, we merely undelay it.
2024 else
2027 else
2031 -- Insert in entity list of scope of base type (which
2032 -- must be an enclosing scope, because still unfrozen).
2038 -- If the component is an access type with an allocator as default
2039 -- value, the designated type will be frozen by the corresponding
2040 -- expression in init_proc. In order to place the freeze node for
2041 -- the designated type before that for the current record type,
2042 -- freeze it now.
2044 -- Same process if the component is an array of access types,
2045 -- initialized with an aggregate. If the designated type is
2046 -- private, it cannot contain allocators, and it is premature
2047 -- to freeze the type, so we check for this as well.
2052 then
2053 declare
2057 begin
2060 -- If component is pointer to a classwide type, freeze
2061 -- the specific type in the expression being allocated.
2062 -- The expression may be a subtype indication, in which
2063 -- case freeze the subtype mark.
2065 if Is_Class_Wide_Type
2067 then
2069 Freeze_And_Append
2071 elsif
2073 then
2074 Freeze_And_Append
2082 else
2083 Freeze_And_Append
2091 then
2100 and then Is_Fully_Defined
2102 then
2103 Freeze_And_Append
2104 (Designated_Type
2112 -- Deal with pragma Bit_Order
2116 ADC :=
2118 Error_Msg_N
2120 Error_Msg_N
2123 -- Here is where we do Ada 2005 processing for bit order (the Ada
2124 -- 95 case was already taken care of above).
2131 -- Set OK_To_Reorder_Components depending on debug flags
2135 then
2137 or else
2139 then
2144 -- Check for useless pragma Pack when all components placed. We only
2145 -- do this check for record types, not subtypes, since a subtype may
2146 -- have all its components placed, and it still makes perfectly good
2147 -- sense to pack other subtypes or the parent type. We do not give
2148 -- this warning if Optimize_Alignment is set to Space, since the
2149 -- pragma Pack does have an effect in this case (it always resets
2150 -- the alignment to one).
2154 and then not Unplaced_Component
2156 then
2157 -- Reset packed status. Probably not necessary, but we do it so
2158 -- that there is no chance of the back end doing something strange
2159 -- with this redundant indication of packing.
2163 -- Give warning if redundant constructs warnings on
2166 Error_Msg_N
2172 -- If this is the record corresponding to a remote type, freeze the
2173 -- remote type here since that is what we are semantically freezing.
2174 -- This prevents the freeze node for that type in an inner scope.
2176 -- Also, Check for controlled components and unchecked unions.
2177 -- Finally, enforce the restriction that access attributes with a
2178 -- current instance prefix can only apply to limited types.
2182 Freeze_And_Append
2189 -- Do not set Has_Controlled_Component on a class-wide
2190 -- equivalent type. See Make_CW_Equivalent_Type.
2197 and then Present
2198 (Corresponding_Record_Type
2200 and then Has_Controlled_Component
2201 (Corresponding_Record_Type
2203 then
2214 -- Scan component declaration for likely misuses of current
2215 -- instance, either in a constraint or a default expression.
2226 -- For first subtypes, check if there are any fixed-point fields with
2227 -- component clauses, where we must check the size. This is not done
2228 -- till the freeze point, since for fixed-point types, we do not know
2229 -- the size until the type is frozen. Similar processing applies to
2230 -- bit packed arrays.
2238 or else
2240 then
2241 Check_Size
2245 Junk);
2252 -- Generate warning for applying C or C++ convention to a record
2253 -- with discriminants. This is suppressed for the unchecked union
2254 -- case, since the whole point in this case is interface C. We also
2255 -- do not generate this within instantiations, since we will have
2256 -- generated a message on the template.
2261 or else
2264 and then not In_Instance
2267 then
2268 declare
2272 begin
2277 Error_Msg_N
2279 else
2280 Error_Msg_N
2284 Error_Msg_NE
2290 -- See if Size is too small as is (and implicit packing might help)
2294 -- No implicit packing if even one component is explicitly placed
2296 and then not Placed_Component
2298 -- Must have size clause and all scalar components
2301 and then All_Scalar_Components
2303 -- Do not try implicit packing on records with discriminants, too
2304 -- complicated, especially in the variant record case.
2308 -- We can implicitly pack if the specified size of the record is
2309 -- less than the sum of the object sizes (no point in packing if
2310 -- this is not the case).
2314 -- And the total RM size cannot be greater than the specified size
2315 -- since otherwise packing will not get us where we have to be!
2319 -- Never do implicit packing in CodePeer mode since we don't do
2320 -- any packing ever in this mode (why not???)
2322 and then not CodePeer_Mode
2323 then
2324 -- If implicit packing enabled, do it
2329 -- Otherwise flag the size clause
2331 else
2332 declare
2334 begin
2335 Error_Msg_NE -- CODEFIX
2337 Error_Msg_N -- CODEFIX
2345 -- Start of processing for Freeze_Entity
2347 begin
2348 -- We are going to test for various reasons why this entity need not be
2349 -- frozen here, but in the case of an Itype that's defined within a
2350 -- record, that test actually applies to the record.
2356 then
2360 -- Do not freeze if already frozen since we only need one freeze node
2365 -- It is improper to freeze an external entity within a generic because
2366 -- its freeze node will appear in a non-valid context. The entity will
2367 -- be frozen in the proper scope after the current generic is analyzed.
2372 -- Do not freeze a global entity within an inner scope created during
2373 -- expansion. A call to subprogram E within some internal procedure
2374 -- (a stream attribute for example) might require freezing E, but the
2375 -- freeze node must appear in the same declarative part as E itself.
2376 -- The two-pass elaboration mechanism in gigi guarantees that E will
2377 -- be frozen before the inner call is elaborated. We exclude constants
2378 -- from this test, because deferred constants may be frozen early, and
2379 -- must be diagnosed (e.g. in the case of a deferred constant being used
2380 -- in a default expression). If the enclosing subprogram comes from
2381 -- source, or is a generic instance, then the freeze point is the one
2382 -- mandated by the language, and we freeze the entity. A subprogram that
2383 -- is a child unit body that acts as a spec does not have a spec that
2384 -- comes from source, but can only come from source.
2389 then
2390 declare
2393 begin
2399 then
2401 else
2410 -- Similarly, an inlined instance body may make reference to global
2411 -- entities, but these references cannot be the proper freezing point
2412 -- for them, and in the absence of inlining freezing will take place in
2413 -- their own scope. Normally instance bodies are analyzed after the
2414 -- enclosing compilation, and everything has been frozen at the proper
2415 -- place, but with front-end inlining an instance body is compiled
2416 -- before the end of the enclosing scope, and as a result out-of-order
2417 -- freezing must be prevented.
2419 elsif Front_End_Inlining
2420 and then In_Instance_Body
2422 then
2423 declare
2426 begin
2430 else
2441 -- Here to freeze the entity
2446 -- Case of entity being frozen is other than a type
2450 -- If entity is exported or imported and does not have an external
2451 -- name, now is the time to provide the appropriate default name.
2452 -- Skip this if the entity is stubbed, since we don't need a name
2453 -- for any stubbed routine. For the case on intrinsics, if no
2454 -- external name is specified, then calls will be handled in
2455 -- Exp_Intr.Expand_Intrinsic_Call, and no name is needed; if
2456 -- an external name is provided, then Expand_Intrinsic_Call leaves
2457 -- calls in place for expansion by GIGI.
2463 then
2464 Set_Encoded_Interface_Name
2467 -- If entity is an atomic object appearing in a declaration and
2468 -- the expression is an aggregate, assign it to a temporary to
2469 -- ensure that the actual assignment is done atomically rather
2470 -- than component-wise (the assignment to the temp may be done
2471 -- component-wise, but that is harmless).
2477 and then
2479 then
2483 -- For a subprogram, freeze all parameter types and also the return
2484 -- type (RM 13.14(14)). However skip this for internal subprograms.
2485 -- This is also the point where any extra formal parameters are
2486 -- created since we now know whether the subprogram will use a
2487 -- foreign convention.
2491 declare
2496 begin
2497 -- Loop through formals
2509 then
2510 -- If the type of a formal is incomplete, subprogram
2511 -- is being frozen prematurely. Within an instance
2512 -- (but not within a wrapper package) this is an
2513 -- artifact of our need to regard the end of an
2514 -- instantiation as a freeze point. Otherwise it is
2515 -- a definite error.
2521 elsif not After_Last_Declaration
2522 and then not Freezing_Library_Level_Tagged_Type
2523 then
2525 Error_Msg
2527 Loc);
2531 -- Check suspicious parameter for C function. These tests
2532 -- apply only to exported/imported subprograms.
2534 if Warn_On_Export_Import
2537 or else
2544 then
2545 -- Qualify mention of formals with subprogram name
2549 -- Check suspicious use of fat C pointer
2553 then
2554 Error_Msg_N
2556 Formal);
2558 -- Check suspicious return of boolean
2565 then
2566 Error_Msg_N
2568 Error_Msg_N
2572 -- Check suspicious tagged type
2576 and then
2577 Is_Tagged_Type
2580 then
2581 Error_Msg_N
2585 -- Check wrong convention subprogram pointer
2589 then
2590 Error_Msg_N
2594 Error_Msg_NE
2599 -- Turn off name qualification after message output
2604 -- Check for unconstrained array in exported foreign
2605 -- convention case.
2611 and then Warn_On_Export_Import
2613 -- Exclude VM case, since both .NET and JVM can handle
2614 -- unconstrained arrays without a problem.
2617 then
2620 -- If this is an inherited operation, place the
2621 -- warning on the derived type declaration, rather
2622 -- than on the original subprogram.
2625 N_Full_Type_Declaration
2626 then
2630 Error_Msg_NE
2633 else
2637 Error_Msg_NE
2640 Error_Msg_NE
2651 -- If the formal is an anonymous_access_to_subprogram
2652 -- freeze the subprogram type as well, to prevent
2653 -- scope anomalies in gigi, because there is no other
2654 -- clear point at which it could be frozen.
2658 then
2666 -- Case of function: similar checks on return type
2670 -- Freeze return type
2675 -- Check suspicious return type for C function
2677 if Warn_On_Export_Import
2679 or else
2682 then
2683 -- Check suspicious return of fat C pointer
2689 then
2690 Error_Msg_N
2694 -- Check suspicious return of boolean
2702 then
2703 declare
2706 begin
2707 Error_Msg_NE
2710 Error_Msg_NE
2715 -- Check suspicious return tagged type
2719 and then
2720 Is_Tagged_Type
2725 then
2726 Error_Msg_N
2730 -- Check return of wrong convention subprogram pointer
2736 then
2737 Error_Msg_N
2741 Error_Msg_NE
2747 -- Give warning for suspicous return of a result of an
2748 -- unconstrained array type in a foreign convention
2749 -- function.
2753 -- We are looking for a return of unconstrained array
2758 -- Exclude imported routines, the warning does not
2759 -- belong on the import, but on the routine definition.
2763 -- Exclude VM case, since both .NET and JVM can handle
2764 -- return of unconstrained arrays without a problem.
2768 -- Check that general warning is enabled, and that it
2769 -- is not suppressed for this particular case.
2771 and then Warn_On_Export_Import
2774 then
2775 Error_Msg_N
2783 -- Must freeze its parent first if it is a derived subprogram
2789 -- We don't freeze internal subprograms, because we don't normally
2790 -- want addition of extra formals or mechanism setting to happen
2791 -- for those. However we do pass through predefined dispatching
2792 -- cases, since extra formals may be needed in some cases, such as
2793 -- for the stream 'Input function (build-in-place formals).
2797 then
2801 -- Here for other than a subprogram or type
2803 else
2804 -- If entity has a type, and it is not a generic unit, then
2805 -- freeze it first (RM 13.14(10)).
2809 then
2813 -- Special processing for objects created by object declaration
2817 -- Abstract type allowed only for C++ imported variables or
2818 -- constants.
2820 -- Note: we inhibit this check for objects that do not come
2821 -- from source because there is at least one case (the
2822 -- expansion of x'class'input where x is abstract) where we
2823 -- legitimately generate an abstract object.
2829 then
2839 -- For object created by object declaration, perform required
2840 -- categorization (preelaborate and pure) checks. Defer these
2841 -- checks to freeze time since pragma Import inhibits default
2842 -- initialization and thus pragma Import affects these checks.
2846 -- If there is an address clause, check that it is valid
2850 -- If the object needs any kind of default initialization, an
2851 -- error must be issued if No_Default_Initialization applies.
2852 -- The check doesn't apply to imported objects, which are not
2853 -- ever default initialized, and is why the check is deferred
2854 -- until freezing, at which point we know if Import applies.
2855 -- Deferred constants are also exempted from this test because
2856 -- their completion is explicit, or through an import pragma.
2860 then
2866 and then
2871 or else
2874 then
2876 Check_Restriction
2880 -- Check that a Thread_Local_Storage variable does not have
2881 -- default initialization, and any explicit initialization must
2882 -- either be the null constant or a static constant.
2885 declare
2887 begin
2888 if Has_Default_Initialization
2889 or else
2891 and then
2893 or else not
2895 or else
2897 then
2898 Error_Msg_NE
2901 Error_Msg_NE
2908 -- For imported objects, set Is_Public unless there is also an
2909 -- address clause, which means that there is no external symbol
2910 -- needed for the Import (Is_Public may still be set for other
2911 -- unrelated reasons). Note that we delayed this processing
2912 -- till freeze time so that we can be sure not to set the flag
2913 -- if there is an address clause. If there is such a clause,
2914 -- then the only purpose of the Import pragma is to suppress
2915 -- implicit initialization.
2919 then
2923 -- For convention C objects of an enumeration type, warn if
2924 -- the size is not integer size and no explicit size given.
2925 -- Skip warning for Boolean, and Character, assume programmer
2926 -- expects 8-bit sizes for these cases.
2929 or else
2936 then
2938 Error_Msg_N
2940 E);
2945 -- Check that a constant which has a pragma Volatile[_Components]
2946 -- or Atomic[_Components] also has a pragma Import (RM C.6(13)).
2948 -- Note: Atomic[_Components] also sets Volatile[_Components]
2953 then
2954 -- Make sure we actually have a pragma, and have not merely
2955 -- inherited the indication from elsewhere (e.g. an address
2956 -- clause, which is not good enough in RM terms!)
2959 or else
2961 then
2962 Error_Msg_N
2967 or else
2969 then
2970 Error_Msg_N
2976 -- Static objects require special handling
2980 then
2984 -- Remaining step is to layout objects
2987 or else
2989 or else
2991 or else
2993 then
2998 -- Case of a type or subtype being frozen
3000 else
3001 -- We used to check here that a full type must have preelaborable
3002 -- initialization if it completes a private type specified with
3003 -- pragma Preelaborable_Intialization, but that missed cases where
3004 -- the types occur within a generic package, since the freezing
3005 -- that occurs within a containing scope generally skips traversal
3006 -- of a generic unit's declarations (those will be frozen within
3007 -- instances). This check was moved to Analyze_Package_Specification.
3009 -- The type may be defined in a generic unit. This can occur when
3010 -- freezing a generic function that returns the type (which is
3011 -- defined in a parent unit). It is clearly meaningless to freeze
3012 -- this type. However, if it is a subtype, its size may be determi-
3013 -- nable and used in subsequent checks, so might as well try to
3014 -- compute it.
3018 then
3023 -- Deal with special cases of freezing for subtype
3027 -- Before we do anything else, a specialized test for the case of
3028 -- a size given for an array where the array needs to be packed,
3029 -- but was not so the size cannot be honored. This would of course
3030 -- be caught by the backend, and indeed we don't catch all cases.
3031 -- The point is that we can give a better error message in those
3032 -- cases that we do catch with the circuitry here. Also if pragma
3033 -- Implicit_Packing is set, this is where the packing occurs.
3035 -- The reason we do this so early is that the processing in the
3036 -- automatic packing case affects the layout of the base type, so
3037 -- it must be done before we freeze the base type.
3040 declare
3044 begin
3045 -- Check enabling conditions. These are straightforward
3046 -- except for the test for a limited composite type. This
3047 -- eliminates the rare case of a array of limited components
3048 -- where there are issues of whether or not we can go ahead
3049 -- and pack the array (since we can't freely pack and unpack
3050 -- arrays if they are limited).
3052 -- Note that we check the root type explicitly because the
3053 -- whole point is we are doing this test before we have had
3054 -- a chance to freeze the base type (and it is that freeze
3055 -- action that causes stuff to be inherited).
3067 and then not CodePeer_Mode
3068 then
3075 then
3076 declare
3086 -- What we are looking for here is the situation where
3087 -- the RM_Size given would be exactly right if there
3088 -- was a pragma Pack (resulting in the component size
3089 -- being the same as the RM_Size). Furthermore, the
3090 -- component type size must be an odd size (not a
3091 -- multiple of storage unit). If the component RM size
3092 -- is an exact number of storage units that is a power
3093 -- of two, the array is not packed and has a standard
3094 -- representation.
3096 begin
3099 then
3100 -- For implicit packing mode, just set the
3101 -- component size silently.
3109 -- Otherwise give an error message
3111 else
3112 Error_Msg_NE
3114 Error_Msg_N
3120 and then Implicit_Packing
3121 and then
3125 then
3127 -- Not a packed array, but indicate the desired
3128 -- component size, for the back-end.
3138 -- If ancestor subtype present, freeze that first. Note that this
3139 -- will also get the base type frozen.
3146 -- Otherwise freeze the base type of the entity before freezing
3147 -- the entity itself (RM 13.14(15)).
3153 -- For a derived type, freeze its parent type first (RM 13.14(15))
3160 -- For array type, freeze index types and component type first
3161 -- before freezing the array (RM 13.14(15)).
3164 declare
3168 -- Set true if any of the index types is an enumeration type
3169 -- with a non-standard representation.
3171 begin
3180 then
3187 -- Processing that is done only for base types
3191 -- Propagate flags for component type
3195 then
3203 -- If packing was requested or if the component size was set
3204 -- explicitly, then see if bit packing is required. This
3205 -- processing is only done for base types, since all the
3206 -- representation aspects involved are type-related. This
3207 -- is not just an optimization, if we start processing the
3208 -- subtypes, they interfere with the settings on the base
3209 -- type (this is because Is_Packed has a slightly different
3210 -- meaning before and after freezing).
3212 declare
3216 begin
3220 then
3229 else
3232 -- We can set the component size if it is less than
3233 -- 16, rounding it up to the next storage unit size.
3239 else
3243 -- Set component size up to match alignment if it
3244 -- would otherwise be less than the alignment. This
3245 -- deals with cases of types whose alignment exceeds
3246 -- their size (padded types).
3249 declare
3251 begin
3259 -- Case of component size that may result in packing
3262 declare
3268 Get_Attribute_Definition_Clause
3270 begin
3271 -- Warn if we have pack and component size so that
3272 -- the pack is ignored.
3274 -- Note: here we must check for the presence of a
3275 -- component size before checking for a Pack pragma
3276 -- to deal with the case where the array type is a
3277 -- derived type whose parent is currently private.
3281 then
3283 Error_Msg_NE
3286 Error_Msg_N
3288 Pack_Pragma);
3291 -- Set component size if not already set by a
3292 -- component size clause.
3298 -- Check for base type of 8, 16, 32 bits, where an
3299 -- unsigned subtype has a length one less than the
3300 -- base type (e.g. Natural subtype of Integer).
3302 -- In such cases, if a component size was not set
3303 -- explicitly, then generate a warning.
3307 and then
3310 then
3314 Error_Msg_N
3317 Error_Msg_N
3323 -- Actual packing is not needed for 8, 16, 32, 64.
3324 -- Also not needed for 24 if alignment is 1.
3331 then
3332 -- Here the array was requested to be packed,
3333 -- but the packing request had no effect, so
3334 -- Is_Packed is reset.
3336 -- Note: semantically this means that we lose
3337 -- track of the fact that a derived type
3338 -- inherited a pragma Pack that was non-
3339 -- effective, but that seems fine.
3341 -- We regard a Pack pragma as a request to set
3342 -- a representation characteristic, and this
3343 -- request may be ignored.
3347 -- In all other cases, packing is indeed needed
3349 else
3358 -- Processing that is done only for subtypes
3360 else
3361 -- Acquire alignment from base type
3369 -- For bit-packed arrays, check the size
3372 declare
3378 begin
3379 -- It is not clear if it is possible to have no size
3380 -- clause at this stage, but it is not worth worrying
3381 -- about. Post error on the entity name in the size
3382 -- clause if present, else on the type entity itself.
3386 else
3392 -- If any of the index types was an enumeration type with
3393 -- a non-standard rep clause, then we indicate that the
3394 -- array type is always packed (even if it is not bit packed).
3403 -- If the array is packed, we must create the packed array
3404 -- type to be used to actually implement the type. This is
3405 -- only needed for real array types (not for string literal
3406 -- types, since they are present only for the front end).
3410 then
3414 -- Size information of packed array type is copied to the
3415 -- array type, since this is really the representation. But
3416 -- do not override explicit existing size values. If the
3417 -- ancestor subtype is constrained the packed_array_type
3418 -- will be inherited from it, but the size may have been
3419 -- provided already, and must not be overridden either.
3422 and then
3425 then
3435 -- For non-packed arrays set the alignment of the array to the
3436 -- alignment of the component type if it is unknown. Skip this
3437 -- in atomic case (atomic arrays may need larger alignments).
3446 then
3451 -- For a class-wide type, the corresponding specific type is
3452 -- frozen as well (RM 13.14(15))
3457 -- If the base type of the class-wide type is still incomplete,
3458 -- the class-wide remains unfrozen as well. This is legal when
3459 -- E is the formal of a primitive operation of some other type
3460 -- which is being frozen.
3467 -- If the Class_Wide_Type is an Itype (when type is the anonymous
3468 -- parent of a derived type) and it is a library-level entity,
3469 -- generate an itype reference for it. Otherwise, its first
3470 -- explicit reference may be in an inner scope, which will be
3471 -- rejected by the back-end.
3475 then
3476 declare
3479 begin
3483 else
3489 -- The equivalent type associated with a class-wide subtype needs
3490 -- to be frozen to ensure that its layout is done.
3494 then
3498 -- For a record (sub)type, freeze all the component types (RM
3499 -- 13.14(15). We test for E_Record_(sub)Type here, rather than using
3500 -- Is_Record_Type, because we don't want to attempt the freeze for
3501 -- the case of a private type with record extension (we will do that
3502 -- later when the full type is frozen).
3506 then
3509 -- For a concurrent type, freeze corresponding record type. This
3510 -- does not correspond to any specific rule in the RM, but the
3511 -- record type is essentially part of the concurrent type.
3512 -- Freeze as well all local entities. This includes record types
3513 -- created for entry parameter blocks, and whatever local entities
3514 -- may appear in the private part.
3518 Freeze_And_Append
3530 then
3540 -- Private types are required to point to the same freeze node as
3541 -- their corresponding full views. The freeze node itself has to
3542 -- point to the partial view of the entity (because from the partial
3543 -- view, we can retrieve the full view, but not the reverse).
3544 -- However, in order to freeze correctly, we need to freeze the full
3545 -- view. If we are freezing at the end of a scope (or within the
3546 -- scope of the private type), the partial and full views will have
3547 -- been swapped, the full view appears first in the entity chain and
3548 -- the swapping mechanism ensures that the pointers are properly set
3549 -- (on scope exit).
3551 -- If we encounter the partial view before the full view (e.g. when
3552 -- freezing from another scope), we freeze the full view, and then
3553 -- set the pointers appropriately since we cannot rely on swapping to
3554 -- fix things up (subtypes in an outer scope might not get swapped).
3558 then
3559 -- The construction of the dispatch table associated with library
3560 -- level tagged types forces freezing of all the primitives of the
3561 -- type, which may cause premature freezing of the partial view.
3562 -- For example:
3564 -- package Pkg is
3565 -- type T is tagged private;
3566 -- type DT is new T with private;
3567 -- procedure Prim (X : in out T; Y : in out DT'class);
3568 -- private
3569 -- type T is tagged null record;
3570 -- Obj : T;
3571 -- type DT is new T with null record;
3572 -- end;
3574 -- In this case the type will be frozen later by the usual
3575 -- mechanism: an object declaration, an instantiation, or the
3576 -- end of a declarative part.
3580 then
3584 -- Case of full view present
3588 -- If full view has already been frozen, then no further
3589 -- processing is required
3597 -- Otherwise freeze full view and patch the pointers so that
3598 -- the freeze node will elaborate both views in the back-end.
3600 else
3601 declare
3604 begin
3607 then
3608 Freeze_And_Append
3621 else
3622 -- {Incomplete,Private}_Subtypes with Full_Views
3623 -- constrained by discriminants.
3634 -- AI-117 requires that the convention of a partial view be the
3635 -- same as the convention of the full view. Note that this is a
3636 -- recognized breach of privacy, but it's essential for logical
3637 -- consistency of representation, and the lack of a rule in
3638 -- RM95 was an oversight.
3645 -- Size information is copied from the full view to the
3646 -- incomplete or private view for consistency.
3648 -- We skip this is the full view is not a type. This is very
3649 -- strange of course, and can only happen as a result of
3650 -- certain illegalities, such as a premature attempt to derive
3651 -- from an incomplete type.
3660 -- Case of no full view present. If entity is derived or subtype,
3661 -- it is safe to freeze, correctness depends on the frozen status
3662 -- of parent. Otherwise it is either premature usage, or a Taft
3663 -- amendment type, so diagnosis is at the point of use and the
3664 -- type might be frozen later.
3668 then
3671 else
3676 -- For access subprogram, freeze types of all formals, the return
3677 -- type was already frozen, since it is the Etype of the function.
3678 -- Formal types can be tagged Taft amendment types, but otherwise
3679 -- they cannot be incomplete.
3688 then
3691 else
3692 Error_Msg_NE
3703 -- For access to a protected subprogram, freeze the equivalent type
3704 -- (however this is not set if we are not generating code or if this
3705 -- is an anonymous type used just for resolution).
3713 -- Generic types are never seen by the back-end, and are also not
3714 -- processed by the expander (since the expander is turned off for
3715 -- generic processing), so we never need freeze nodes for them.
3721 -- Some special processing for non-generic types to complete
3722 -- representation details not known till the freeze point.
3727 -- Some error checks required for ordinary fixed-point type. Defer
3728 -- these till the freeze-point since we need the small and range
3729 -- values. We only do these checks for base types
3733 then
3736 Error_Msg_N
3741 Error_Msg_N
3747 Error_Msg_N
3753 Error_Msg_N
3765 and then Warn_On_Suspicious_Modulus_Value
3766 then
3772 -- Check restriction for standard storage pool
3778 -- Deal with error message for pure access type. This is not an
3779 -- error in Ada 2005 if there is no pool (see AI-366).
3784 then
3788 Error_Msg_N
3792 Error_Msg_N
3795 else
3796 Error_Msg_N
3803 -- Case of composite types
3807 -- AI-117 requires that all new primitives of a tagged type must
3808 -- inherit the convention of the full view of the type. Inherited
3809 -- and overriding operations are defined to inherit the convention
3810 -- of their parent or overridden subprogram (also specified in
3811 -- AI-117), which will have occurred earlier (in Derive_Subprogram
3812 -- and New_Overloaded_Entity). Here we set the convention of
3813 -- primitives that are still convention Ada, which will ensure
3814 -- that any new primitives inherit the type's convention. Class-
3815 -- wide types can have a foreign convention inherited from their
3816 -- specific type, but are excluded from this since they don't have
3817 -- any associated primitives.
3822 then
3823 declare
3826 begin
3839 -- Now that all types from which E may depend are frozen, see if the
3840 -- size is known at compile time, if it must be unsigned, or if
3841 -- strict alignment is required
3850 -- Do not allow a size clause for a type which does not have a size
3851 -- that is known at compile time
3855 then
3856 -- Suppress this message if errors posted on E, even if we are
3857 -- in all errors mode, since this is often a junk message
3860 Error_Msg_N
3866 -- Remaining process is to set/verify the representation information,
3867 -- in particular the size and alignment values. This processing is
3868 -- not required for generic types, since generic types do not play
3869 -- any part in code generation, and so the size and alignment values
3870 -- for such types are irrelevant.
3875 -- Otherwise we call the layout procedure
3877 else
3881 -- End of freeze processing for type entities
3884 -- Here is where we logically freeze the current entity. If it has a
3885 -- freeze node, then this is the point at which the freeze node is
3886 -- linked into the result list.
3890 -- If a freeze node is already allocated, use it, otherwise allocate
3891 -- a new one. The preallocation happens in the case of anonymous base
3892 -- types, where we preallocate so that we can set First_Subtype_Link.
3893 -- Note that we reset the Sloc to the current freeze location.
3899 else
3911 else
3915 -- A final pass over record types with discriminants. If the type
3916 -- has an incomplete declaration, there may be constrained access
3917 -- subtypes declared elsewhere, which do not depend on the discrimi-
3918 -- nants of the type, and which are used as component types (i.e.
3919 -- the full view is a recursive type). The designated types of these
3920 -- subtypes can only be elaborated after the type itself, and they
3921 -- need an itype reference.
3925 then
3926 declare
3931 begin
3942 then
3954 -- When a type is frozen, the first subtype of the type is frozen as
3955 -- well (RM 13.14(15)). This has to be done after freezing the type,
3956 -- since obviously the first subtype depends on its own base type.
3961 -- If we just froze a tagged non-class wide record, then freeze the
3962 -- corresponding class-wide type. This must be done after the tagged
3963 -- type itself is frozen, because the class-wide type refers to the
3964 -- tagged type which generates the class.
3969 then
3976 -- Special handling for subprograms
3980 -- If subprogram has address clause then reset Is_Public flag, since
3981 -- we do not want the backend to generate external references.
3985 then
3988 -- If no address clause and not intrinsic, then for imported
3989 -- subprogram in main unit, generate descriptor if we are in
3990 -- Propagate_Exceptions mode.
3992 elsif Propagate_Exceptions
3996 then
4006 -----------------------------
4007 -- Freeze_Enumeration_Type --
4008 -----------------------------
4011 begin
4012 -- By default, if no size clause is present, an enumeration type with
4013 -- Convention C is assumed to interface to a C enum, and has integer
4014 -- size. This applies to types. For subtypes, verify that its base
4015 -- type has no size clause either.
4021 then
4024 else
4025 -- If the enumeration type interfaces to C, and it has a size clause
4026 -- that specifies less than int size, it warrants a warning. The
4027 -- user may intend the C type to be an enum or a char, so this is
4028 -- not by itself an error that the Ada compiler can detect, but it
4029 -- it is a worth a heads-up. For Boolean and Character types we
4030 -- assume that the programmer has the proper C type in mind.
4037 then
4038 Error_Msg_N
4046 -----------------------
4047 -- Freeze_Expression --
4048 -----------------------
4059 -- This flag is set true if the entity must be frozen outside the
4060 -- current subprogram. This happens in the case of expander generated
4061 -- subprograms (_Init_Proc, _Input, _Output, _Read, _Write) which do
4062 -- not freeze all entities like other bodies, but which nevertheless
4063 -- may reference entities that have to be frozen before the body and
4064 -- obviously cannot be frozen inside the body.
4067 -- Given an N_Handled_Sequence_Of_Statements node N, determines whether
4068 -- it is the handled statement sequence of an expander-generated
4069 -- subprogram (init proc, stream subprogram, or renaming as body).
4070 -- If so, this is not a freezing context.
4072 -----------------
4073 -- In_Exp_Body --
4074 -----------------
4080 begin
4083 else
4090 else
4100 N_Subprogram_Renaming_Declaration)
4101 then
4103 else
4109 -- Start of processing for Freeze_Expression
4111 begin
4112 -- Immediate return if freezing is inhibited. This flag is set by the
4113 -- analyzer to stop freezing on generated expressions that would cause
4114 -- freezing if they were in the source program, but which are not
4115 -- supposed to freeze, since they are created.
4121 -- If expression is non-static, then it does not freeze in a default
4122 -- expression, see section "Handling of Default Expressions" in the
4123 -- spec of package Sem for further details. Note that we have to
4124 -- make sure that we actually have a real expression (if we have
4125 -- a subtype indication, we can't test Is_Static_Expression!)
4127 if In_Spec_Exp
4130 then
4134 -- Freeze type of expression if not frozen already
4142 -- Base type may be an derived numeric type that is frozen at
4143 -- the point of declaration, but first_subtype is still unfrozen.
4150 -- For entity name, freeze entity if not frozen already. A special
4151 -- exception occurs for an identifier that did not come from source.
4152 -- We don't let such identifiers freeze a non-internal entity, i.e.
4153 -- an entity that did come from source, since such an identifier was
4154 -- generated by the expander, and cannot have any semantic effect on
4155 -- the freezing semantics. For example, this stops the parameter of
4156 -- an initialization procedure from freezing the variable.
4163 then
4165 else
4169 -- For an allocator freeze designated type if not frozen already
4171 -- For an aggregate whose component type is an access type, freeze the
4172 -- designated type now, so that its freeze does not appear within the
4173 -- loop that might be created in the expansion of the aggregate. If the
4174 -- designated type is a private type without full view, the expression
4175 -- cannot contain an allocator, so the type is not frozen.
4177 -- For a function, we freeze the entity when the subprogram declaration
4178 -- is frozen, but a function call may appear in an initialization proc.
4179 -- before the declaration is frozen. We need to generate the extra
4180 -- formals, if any, to ensure that the expansion of the call includes
4181 -- the proper actuals. This only applies to Ada subprograms, not to
4182 -- imported ones.
4193 then
4197 when N_Selected_Component |
4198 N_Indexed_Component |
4199 N_Slice =>
4210 then
4221 then
4225 -- All done if nothing needs freezing
4230 then
4234 -- Loop for looking at the right place to insert the freeze nodes,
4235 -- exiting from the loop when it is appropriate to insert the freeze
4236 -- node before the current node P.
4238 -- Also checks som special exceptions to the freezing rules. These cases
4239 -- result in a direct return, bypassing the freeze action.
4242 loop
4245 -- If we don't have a parent, then we are not in a well-formed tree.
4246 -- This is an unusual case, but there are some legitimate situations
4247 -- in which this occurs, notably when the expressions in the range of
4248 -- a type declaration are resolved. We simply ignore the freeze
4249 -- request in this case. Is this right ???
4255 -- See if we have got to an appropriate point in the tree
4259 -- A special test for the exception of (RM 13.14(8)) for the case
4260 -- of per-object expressions (RM 3.8(18)) occurring in component
4261 -- definition or a discrete subtype definition. Note that we test
4262 -- for a component declaration which includes both cases we are
4263 -- interested in, and furthermore the tree does not have explicit
4264 -- nodes for either of these two constructs.
4268 -- The case we want to test for here is an identifier that is
4269 -- a per-object expression, this is either a discriminant that
4270 -- appears in a context other than the component declaration
4271 -- or it is a reference to the type of the enclosing construct.
4273 -- For either of these cases, we skip the freezing
4275 if not In_Spec_Expression
4278 then
4279 -- We recognize the discriminant case by just looking for
4280 -- a reference to a discriminant. It can only be one for
4281 -- the enclosing construct. Skip freezing in this case.
4286 -- For the case of a reference to the enclosing record,
4287 -- (or task or protected type), we look for a type that
4288 -- matches the current scope.
4295 -- If we have an enumeration literal that appears as the choice in
4296 -- the aggregate of an enumeration representation clause, then
4297 -- freezing does not occur (RM 13.14(10)).
4301 -- The case we are looking for is an enumeration literal
4305 then
4306 -- If enumeration literal appears directly as the choice,
4307 -- do not freeze (this is the normal non-overloaded case)
4311 then
4314 -- If enumeration literal appears as the name of function
4315 -- which is the choice, then also do not freeze. This
4316 -- happens in the overloaded literal case, where the
4317 -- enumeration literal is temporarily changed to a function
4318 -- call for overloading analysis purposes.
4321 and then
4323 and then
4325 then
4330 -- Normally if the parent is a handled sequence of statements,
4331 -- then the current node must be a statement, and that is an
4332 -- appropriate place to insert a freeze node.
4336 -- An exception occurs when the sequence of statements is for
4337 -- an expander generated body that did not do the usual freeze
4338 -- all operation. In this case we usually want to freeze
4339 -- outside this body, not inside it, and we skip past the
4340 -- subprogram body that we are inside.
4344 -- However, we *do* want to freeze at this point if we have
4345 -- an entity to freeze, and that entity is declared *inside*
4346 -- the body of the expander generated procedure. This case
4347 -- is recognized by the scope of the type, which is either
4348 -- the spec for some enclosing body, or (in the case of
4349 -- init_procs, for which there are no separate specs) the
4350 -- current scope.
4352 declare
4356 begin
4361 or else
4363 then
4369 then
4375 -- If not that exception to the exception, then this is
4376 -- where we delay the freeze till outside the body.
4381 -- Here if normal case where we are in handled statement
4382 -- sequence and want to do the insertion right there.
4384 else
4388 -- If parent is a body or a spec or a block, then the current node
4389 -- is a statement or declaration and we can insert the freeze node
4390 -- before it.
4392 when N_Package_Specification |
4393 N_Package_Body |
4394 N_Subprogram_Body |
4395 N_Task_Body |
4396 N_Protected_Body |
4397 N_Entry_Body |
4400 -- The expander is allowed to define types in any statements list,
4401 -- so any of the following parent nodes also mark a freezing point
4402 -- if the actual node is in a list of statements or declarations.
4404 when N_Exception_Handler |
4405 N_If_Statement |
4406 N_Elsif_Part |
4407 N_Case_Statement_Alternative |
4408 N_Compilation_Unit_Aux |
4409 N_Selective_Accept |
4410 N_Accept_Alternative |
4411 N_Delay_Alternative |
4412 N_Conditional_Entry_Call |
4413 N_Entry_Call_Alternative |
4414 N_Triggering_Alternative |
4415 N_Abortable_Part |
4416 N_Freeze_Entity =>
4420 -- Note: The N_Loop_Statement is a special case. A type that
4421 -- appears in the source can never be frozen in a loop (this
4422 -- occurs only because of a loop expanded by the expander), so we
4423 -- keep on going. Otherwise we terminate the search. Same is true
4424 -- of any entity which comes from source. (if they have predefined
4425 -- type, that type does not appear to come from source, but the
4426 -- entity should not be frozen here).
4432 -- For all other cases, keep looking at parents
4438 -- We fall through the case if we did not yet find the proper
4439 -- place in the free for inserting the freeze node, so climb!
4444 -- If the expression appears in a record or an initialization procedure,
4445 -- the freeze nodes are collected and attached to the current scope, to
4446 -- be inserted and analyzed on exit from the scope, to insure that
4447 -- generated entities appear in the correct scope. If the expression is
4448 -- a default for a discriminant specification, the scope is still void.
4449 -- The expression can also appear in the discriminant part of a private
4450 -- or concurrent type.
4452 -- If the expression appears in a constrained subcomponent of an
4453 -- enclosing record declaration, the freeze nodes must be attached to
4454 -- the outer record type so they can eventually be placed in the
4455 -- enclosing declaration list.
4457 -- The other case requiring this special handling is if we are in a
4458 -- default expression, since in that case we are about to freeze a
4459 -- static type, and the freeze scope needs to be the outer scope, not
4460 -- the scope of the subprogram with the default parameter.
4462 -- For default expressions and other spec expressions in generic units,
4463 -- the Move_Freeze_Nodes mechanism (see sem_ch12.adb) takes care of
4464 -- placing them at the proper place, after the generic unit.
4467 or else Freeze_Outside
4472 then
4473 declare
4478 begin
4491 -- The current scope may be that of a constrained component of
4492 -- an enclosing record declaration, which is above the current
4493 -- scope in the scope stack.
4502 Freeze_Nodes;
4503 else
4513 -- Now we have the right place to do the freezing. First, a special
4514 -- adjustment, if we are in spec-expression analysis mode, these freeze
4515 -- actions must not be thrown away (normally all inserted actions are
4516 -- thrown away in this mode. However, the freeze actions are from static
4517 -- expressions and one of the important reasons we are doing this
4518 -- special analysis is to get these freeze actions. Therefore we turn
4519 -- off the In_Spec_Expression mode to propagate these freeze actions.
4520 -- This also means they get properly analyzed and expanded.
4524 -- Freeze the designated type of an allocator (RM 13.14(13))
4530 -- Freeze type of expression (RM 13.14(10)). Note that we took care of
4531 -- the enumeration representation clause exception in the loop above.
4537 -- Freeze name if one is present (RM 13.14(11))
4543 -- Restore In_Spec_Expression flag
4548 -----------------------------
4549 -- Freeze_Fixed_Point_Type --
4550 -----------------------------
4552 -- Certain fixed-point types and subtypes, including implicit base types
4553 -- and declared first subtypes, have not yet set up a range. This is
4554 -- because the range cannot be set until the Small and Size values are
4555 -- known, and these are not known till the type is frozen.
4557 -- To signal this case, Scalar_Range contains an unanalyzed syntactic range
4558 -- whose bounds are unanalyzed real literals. This routine will recognize
4559 -- this case, and transform this range node into a properly typed range
4560 -- with properly analyzed and resolved values.
4578 -- Returns size of type with given bounds. Also leaves these
4579 -- bounds set as the current bounds of the Typ.
4581 -----------
4582 -- Fsize --
4583 -----------
4586 begin
4592 -- Start of processing for Freeze_Fixed_Point_Type
4594 begin
4595 -- If Esize of a subtype has not previously been set, set it now
4602 else
4607 -- Immediate return if the range is already analyzed. This means that
4608 -- the range is already set, and does not need to be computed by this
4609 -- routine.
4615 -- Immediate return if either of the bounds raises Constraint_Error
4619 then
4626 -- Ordinary fixed-point case
4630 -- For the ordinary fixed-point case, we are allowed to fudge the
4631 -- end-points up or down by small. Generally we prefer to fudge up,
4632 -- i.e. widen the bounds for non-model numbers so that the end points
4633 -- are included. However there are cases in which this cannot be
4634 -- done, and indeed cases in which we may need to narrow the bounds.
4635 -- The following circuit makes the decision.
4637 -- Note: our terminology here is that Incl_EP means that the bounds
4638 -- are widened by Small if necessary to include the end points, and
4639 -- Excl_EP means that the bounds are narrowed by Small to exclude the
4640 -- end-points if this reduces the size.
4642 -- Note that in the Incl case, all we care about is including the
4643 -- end-points. In the Excl case, we want to narrow the bounds as
4644 -- much as permitted by the RM, to give the smallest possible size.
4661 begin
4662 -- First step. Base types are required to be symmetrical. Right
4663 -- now, the base type range is a copy of the first subtype range.
4664 -- This will be corrected before we are done, but right away we
4665 -- need to deal with the case where both bounds are non-negative.
4666 -- In this case, we set the low bound to the negative of the high
4667 -- bound, to make sure that the size is computed to include the
4668 -- required sign. Note that we do not need to worry about the
4669 -- case of both bounds negative, because the sign will be dealt
4670 -- with anyway. Furthermore we can't just go making such a bound
4671 -- symmetrical, since in a twos-complement system, there is an
4672 -- extra negative value which could not be accommodated on the
4673 -- positive side.
4678 then
4683 -- Compute the fudged bounds. If the number is a model number,
4684 -- then we do nothing to include it, but we are allowed to backoff
4685 -- to the next adjacent model number when we exclude it. If it is
4686 -- not a model number then we straddle the two values with the
4687 -- model numbers on either side.
4693 else
4697 -- The low value excluding the end point is Small greater, but
4698 -- we do not do this exclusion if the low value is positive,
4699 -- since it can't help the size and could actually hurt by
4700 -- crossing the high bound.
4705 -- If the value went from negative to zero, then we have the
4706 -- case where Loval_Incl_EP is the model number just below
4707 -- zero, so we want to stick to the negative value for the
4708 -- base type to maintain the condition that the size will
4709 -- include signed values.
4713 then
4717 else
4721 -- Similar processing for upper bound and high value
4727 else
4733 else
4737 -- One further adjustment is needed. In the case of subtypes, we
4738 -- cannot go outside the range of the base type, or we get
4739 -- peculiarities, and the base type range is already set. This
4740 -- only applies to the Incl values, since clearly the Excl values
4741 -- are already as restricted as they are allowed to be.
4748 -- Get size including and excluding end points
4753 -- No need to exclude end-points if it does not reduce size
4763 -- Now we set the actual size to be used. We want to use the
4764 -- bounds fudged up to include the end-points but only if this
4765 -- can be done without violating a specifically given size
4766 -- size clause or causing an unacceptable increase in size.
4768 -- Case of size clause given
4772 -- Use the inclusive size only if it is consistent with
4773 -- the explicitly specified size.
4780 -- If the inclusive size is too large, we try excluding
4781 -- the end-points (will be caught later if does not work).
4783 else
4789 -- Case of size clause not given
4791 else
4792 -- If we have a base type whose corresponding first subtype
4793 -- has an explicit size that is large enough to include our
4794 -- end-points, then do so. There is no point in working hard
4795 -- to get a base type whose size is smaller than the specified
4796 -- size of the first subtype.
4802 then
4807 -- If excluding the end-points makes the size smaller and
4808 -- results in a size of 8,16,32,64, then we take the smaller
4809 -- size. For the 64 case, this is compulsory. For the other
4810 -- cases, it seems reasonable. We like to include end points
4811 -- if we can, but not at the expense of moving to the next
4812 -- natural boundary of size.
4815 and then
4820 then
4825 -- Otherwise we can definitely include the end points
4827 else
4833 -- One pathological case: normally we never fudge a low bound
4834 -- down, since it would seem to increase the size (if it has
4835 -- any effect), but for ranges containing single value, or no
4836 -- values, the high bound can be small too large. Consider:
4838 -- type t is delta 2.0**(-14)
4839 -- range 131072.0 .. 0;
4841 -- That lower bound is *just* outside the range of 32 bits, and
4842 -- does need fudging down in this case. Note that the bounds
4843 -- will always have crossed here, since the high bound will be
4844 -- fudged down if necessary, as in the case of:
4846 -- type t is delta 2.0**(-14)
4847 -- range 131072.0 .. 131072.0;
4849 -- So we detect the situation by looking for crossed bounds,
4850 -- and if the bounds are crossed, and the low bound is greater
4851 -- than zero, we will always back it off by small, since this
4852 -- is completely harmless.
4859 -- And of course, we need to do exactly the same parallel
4860 -- fudge for flat ranges in the negative region.
4873 -- For the decimal case, none of this fudging is required, since there
4874 -- are no end-point problems in the decimal case (the end-points are
4875 -- always included).
4877 else
4881 -- At this stage, the actual size has been calculated and the proper
4882 -- required bounds are stored in the low and high bounds.
4886 Error_Msg_N
4888 Typ);
4892 -- Check size against explicit given size
4898 Error_Msg_NE
4902 else
4906 -- Increase size to next natural boundary if no size clause given
4908 else
4915 else
4923 -- If we have a base type, then expand the bounds so that they extend to
4924 -- the full width of the allocated size in bits, to avoid junk range
4925 -- checks on intermediate computations.
4932 -- Final step is to reanalyze the bounds using the proper type
4933 -- and set the Corresponding_Integer_Value fields of the literals.
4939 -- Resolve with universal fixed if the base type, and the base type if
4940 -- it is a subtype. Note we can't resolve the base type with itself,
4941 -- that would be a reference before definition.
4945 else
4949 -- Set corresponding integer value for bound
4951 Set_Corresponding_Integer_Value
4954 -- Similar processing for high bound
4962 else
4966 Set_Corresponding_Integer_Value
4969 -- Set type of range to correspond to bounds
4973 -- Set Esize to calculated size if not set already
4979 -- Set RM_Size if not already set. If already set, check value
4981 declare
4984 begin
4989 Error_Msg_NE
4994 else
5000 ------------------
5001 -- Freeze_Itype --
5002 ------------------
5007 begin
5016 --------------------------
5017 -- Freeze_Static_Object --
5018 --------------------------
5023 -- Exception raised if the type of a static object cannot be made
5024 -- static. This happens if the type depends on non-global objects.
5027 -- Called to ensure that an expression used as part of a type definition
5028 -- is statically allocatable, which means that the expression type is
5029 -- statically allocatable, and the expression is either static, or a
5030 -- reference to a library level constant.
5033 -- Called to mark a type as static, checking that it is possible
5034 -- to set the type as static. If it is not possible, then the
5035 -- exception Cannot_Be_Static is raised.
5037 -----------------------------
5038 -- Ensure_Expression_Is_SA --
5039 -----------------------------
5044 begin
5056 then
5064 -----------------------
5065 -- Ensure_Type_Is_SA --
5066 -----------------------
5072 begin
5073 -- If type is library level, we are all set
5079 -- We are also OK if the type already marked as statically allocated,
5080 -- which means we processed it before.
5086 -- Mark type as statically allocated
5090 -- Check that it is safe to statically allocate this type
5108 declare
5112 begin
5125 else
5134 then
5153 else
5158 -- Start of processing for Freeze_Static_Object
5160 begin
5163 exception
5166 -- If the object that cannot be static is imported or exported, then
5167 -- issue an error message saying that this object cannot be imported
5168 -- or exported. If it has an address clause it is an overlay in the
5169 -- current partition and the static requirement is not relevant.
5172 Error_Msg_N
5175 -- Otherwise must be exported, something is wrong if compiler
5176 -- is marking something as statically allocated which cannot be).
5179 Error_Msg_N
5184 -----------------------
5185 -- Freeze_Subprogram --
5186 -----------------------
5192 begin
5193 -- Subprogram may not have an address clause unless it is imported
5197 Error_Msg_N
5204 -- Reset the Pure indication on an imported subprogram unless an
5205 -- explicit Pure_Function pragma was present. We do this because
5206 -- otherwise it is an insidious error to call a non-pure function from
5207 -- pure unit and have calls mysteriously optimized away. What happens
5208 -- here is that the Import can bypass the normal check to ensure that
5209 -- pure units call only pure subprograms.
5214 then
5218 -- For non-foreign convention subprograms, this is where we create
5219 -- the extra formals (for accessibility level and constrained bit
5220 -- information). We delay this till the freeze point precisely so
5221 -- that we know the convention!
5227 -- If this is convention Ada and a Valued_Procedure, that's odd
5232 and then Warn_On_Export_Import
5233 then
5234 Error_Msg_N
5239 -- Case of foreign convention
5241 else
5244 -- For foreign conventions, warn about return of an
5245 -- unconstrained array.
5247 -- Note: we *do* allow a return by descriptor for the VMS case,
5248 -- though here there is probably more to be done ???
5253 -- If no return type, probably some other error, e.g. a
5254 -- missing full declaration, so ignore.
5259 -- If the return type is generic, we have emitted a warning
5260 -- earlier on, and there is nothing else to check here. Specific
5261 -- instantiations may lead to erroneous behavior.
5266 -- Display warning if returning unconstrained array
5271 -- Exclude cases where descriptor mechanism is set, since the
5272 -- VMS descriptor mechanisms allow such unconstrained returns.
5276 -- Check appropriate warning is enabled (should we check for
5277 -- Warnings (Off) on specific entities here, probably so???)
5279 and then Warn_On_Export_Import
5281 -- Exclude the VM case, since return of unconstrained arrays
5282 -- is properly handled in both the JVM and .NET cases.
5285 then
5286 Error_Msg_N
5293 -- If any of the formals for an exported foreign convention
5294 -- subprogram have defaults, then emit an appropriate warning since
5295 -- this is odd (default cannot be used from non-Ada code)
5300 if Warn_On_Export_Import
5302 then
5303 Error_Msg_N
5313 -- For VMS, descriptor mechanisms for parameters are allowed only for
5314 -- imported/exported subprograms. Moreover, the NCA descriptor is not
5315 -- allowed for parameters of exported subprograms.
5322 Error_Msg_N
5324 Error_Msg_N
5335 Error_Msg_N
5337 Error_Msg_N
5346 -- Pragma Inline_Always is disallowed for dispatching subprograms
5347 -- because the address of such subprograms is saved in the dispatch
5348 -- table to support dispatching calls, and dispatching calls cannot
5349 -- be inlined. This is consistent with the restriction against using
5350 -- 'Access or 'Address on an Inline_Always subprogram.
5354 then
5355 Error_Msg_N
5359 -- Because of the implicit representation of inherited predefined
5360 -- operators in the front-end, the overriding status of the operation
5361 -- may be affected when a full view of a type is analyzed, and this is
5362 -- not captured by the analysis of the corresponding type declaration.
5363 -- Therefore the correctness of a not-overriding indicator must be
5364 -- rechecked when the subprogram is frozen.
5368 then
5373 ----------------------
5374 -- Is_Fully_Defined --
5375 ----------------------
5378 begin
5387 then
5388 -- Verify that the record type has no components with private types
5389 -- without completion.
5391 declare
5394 begin
5407 else
5413 ---------------------------------
5414 -- Process_Default_Expressions --
5415 ---------------------------------
5417 procedure Process_Default_Expressions
5420 is
5427 begin
5430 -- A subprogram instance and its associated anonymous subprogram share
5431 -- their signature. The default expression functions are defined in the
5432 -- wrapper packages for the anonymous subprogram, and should not be
5433 -- generated again for the instance.
5438 then
5446 -- We work with a copy of the default expression because we
5447 -- do not want to disturb the original, since this would mess
5448 -- up the conformance checking.
5452 -- The analysis of the expression may generate insert actions,
5453 -- which of course must not be executed. We wrap those actions
5454 -- in a procedure that is not called, and later on eliminated.
5455 -- The following cases have no side-effects, and are analyzed
5456 -- directly.
5467 and then
5469 then
5471 -- If there is no default function, we must still do a full
5472 -- analyze call on the default value, to ensure that all error
5473 -- checks are performed, e.g. those associated with static
5474 -- evaluation. Note: this branch will always be taken if the
5475 -- analyzer is turned off (but we still need the error checks).
5477 -- Note: the setting of parent here is to meet the requirement
5478 -- that we can only analyze the expression while attached to
5479 -- the tree. Really the requirement is that the parent chain
5480 -- be set, we don't actually need to be in the tree.
5485 -- Default expressions are resolved with their own type if the
5486 -- context is generic, to avoid anomalies with private types.
5490 else
5494 -- If that resolved expression will raise constraint error,
5495 -- then flag the default value as raising constraint error.
5496 -- This allows a proper error message on the calls.
5502 -- If the default is a parameterless call, we use the name of
5503 -- the called function directly, and there is no body to build.
5507 then
5510 -- Else construct and analyze the body of a wrapper procedure
5511 -- that contains an object declaration to hold the expression.
5512 -- Given that this is done only to complete the analysis, it
5513 -- simpler to build a procedure than a function which might
5514 -- involve secondary stack expansion.
5516 else
5517 Dnam :=
5520 Dbody :=
5522 Specification =>
5528 Defining_Identifier =>
5531 Object_Definition =>
5535 Handled_Statement_Sequence =>
5552 ----------------------------------------
5553 -- Set_Component_Alignment_If_Not_Set --
5554 ----------------------------------------
5557 begin
5558 -- Ignore if not base type, subtypes don't need anything
5564 -- Do not override existing representation
5575 else
5576 Set_Component_Alignment
5582 ------------------
5583 -- Undelay_Type --
5584 ------------------
5587 begin
5591 -- Since we don't want T to have a Freeze_Node, we don't want its
5592 -- Full_View or Corresponding_Record_Type to have one either.
5594 -- ??? Fundamentally, this whole handling is a kludge. What we really
5595 -- want is to be sure that for an Itype that's part of record R and is a
5596 -- subtype of type T, that it's frozen after the later of the freeze
5597 -- points of R and T. We have no way of doing that directly, so what we
5598 -- do is force most such Itypes to be frozen as part of freezing R via
5599 -- this procedure and only delay the ones that need to be delayed
5600 -- (mostly the designated types of access types that are defined as part
5601 -- of the record).
5607 then
5615 then
5620 ------------------
5621 -- Warn_Overlay --
5622 ------------------
5624 procedure Warn_Overlay
5628 is
5630 -- The object to which the address clause applies
5636 begin
5637 -- No warning if address clause overlay warnings are off
5643 -- No warning if there is an explicit initialization
5651 -- We only give the warning for non-imported entities of a type for
5652 -- which a non-null base init proc is defined, or for objects of access
5653 -- types with implicit null initialization, or when Initialize_Scalars
5654 -- applies and the type is scalar or a string type (the latter being
5655 -- tested for because predefined String types are initialized by inline
5656 -- code rather than by an init_proc).
5665 then
5668 then
5673 then
5680 then
5687 -- A function call (most likely to To_Address) is probably not an
5688 -- overlay, so skip warning. Ditto if the function call was inlined
5689 -- and transformed into an entity.
5697 -- If a pragma Import follows, we assume that it is for the current
5698 -- target of the address clause, and skip the warning.
5703 then
5709 Error_Msg_N
5711 Nam);
5712 else
5713 Error_Msg_N
5715 Nam);
5718 -- Add friendly warning if initialization comes from a packed array
5719 -- component.
5722 declare
5725 begin
5731 then
5735 then
5736 Error_Msg_NE
5741 else
5748 Error_Msg_N
5751 Nam);