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1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- F R E E Z E --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1992-2014, Free Software Foundation, Inc. --
10 -- --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
20 -- --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
23 -- --
24 ------------------------------------------------------------------------------
72 -----------------------
73 -- Local Subprograms --
74 -----------------------
77 -- Typ is a type that is being frozen. If no size clause is given,
78 -- but a default Esize has been computed, then this default Esize is
79 -- adjusted up if necessary to be consistent with a given alignment,
80 -- but never to a value greater than Long_Long_Integer'Size. This
81 -- is used for all discrete types and for fixed-point types.
83 procedure Build_And_Analyze_Renamed_Body
87 -- Build body for a renaming declaration, insert in tree and analyze
90 -- Apply legality checks to address clauses for object declarations,
91 -- at the point the object is frozen. Also ensure any initialization is
92 -- performed only after the object has been frozen.
94 procedure Check_Component_Storage_Order
99 -- For an Encl_Type that has a Scalar_Storage_Order attribute definition
100 -- clause, verify that the component type has an explicit and compatible
101 -- attribute/aspect. For arrays, Comp is Empty; for records, it is the
102 -- entity of the component under consideration. For an Encl_Type that
103 -- does not have a Scalar_Storage_Order attribute definition clause,
104 -- verify that the component also does not have such a clause.
105 -- ADC is the attribute definition clause if present (or Empty). On return,
106 -- Comp_ADC_Present is set True if the component has a Scalar_Storage_Order
107 -- attribute definition clause.
110 -- When an expression function is frozen by a use of it, the expression
111 -- itself is frozen. Check that the expression does not include references
112 -- to deferred constants without completion. We report this at the freeze
113 -- point of the function, to provide a better error message.
116 -- E is a base type. If E is tagged or has a component that is aliased
117 -- or tagged or contains something this is aliased or tagged, set
118 -- Strict_Alignment.
122 -- If E is a fixed-point or discrete type, then all the necessary work
123 -- to freeze it is completed except for possible setting of the flag
124 -- Is_Unsigned_Type, which is done by this procedure. The call has no
125 -- effect if the entity E is not a discrete or fixed-point type.
127 procedure Freeze_And_Append
131 -- Freezes Ent using Freeze_Entity, and appends the resulting list of
132 -- nodes to Result, modifying Result from No_List if necessary. N has
133 -- the same usage as in Freeze_Entity.
136 -- Freeze enumeration type. The Esize field is set as processing
137 -- proceeds (i.e. set by default when the type is declared and then
138 -- adjusted by rep clauses. What this procedure does is to make sure
139 -- that if a foreign convention is specified, and no specific size
140 -- is given, then the size must be at least Integer'Size.
143 -- If an object is frozen which has Is_Statically_Allocated set, then
144 -- all referenced types must also be marked with this flag. This routine
145 -- is in charge of meeting this requirement for the object entity E.
148 -- Perform freezing actions for a subprogram (create extra formals,
149 -- and set proper default mechanism values). Note that this routine
150 -- is not called for internal subprograms, for which neither of these
151 -- actions is needed (or desirable, we do not want for example to have
152 -- these extra formals present in initialization procedures, where they
153 -- would serve no purpose). In this call E is either a subprogram or
154 -- a subprogram type (i.e. an access to a subprogram).
157 -- True if T is not private and has no private components, or has a full
158 -- view. Used to determine whether the designated type of an access type
159 -- should be frozen when the access type is frozen. This is done when an
160 -- allocator is frozen, or an expression that may involve attributes of
161 -- the designated type. Otherwise freezing the access type does not freeze
162 -- the designated type.
164 procedure Process_Default_Expressions
167 -- This procedure is called for each subprogram to complete processing of
168 -- default expressions at the point where all types are known to be frozen.
169 -- The expressions must be analyzed in full, to make sure that all error
170 -- processing is done (they have only been pre-analyzed). If the expression
171 -- is not an entity or literal, its analysis may generate code which must
172 -- not be executed. In that case we build a function body to hold that
173 -- code. This wrapper function serves no other purpose (it used to be
174 -- called to evaluate the default, but now the default is inlined at each
175 -- point of call).
178 -- Typ is a record or array type that is being frozen. This routine sets
179 -- the default component alignment from the scope stack values if the
180 -- alignment is otherwise not specified.
183 -- As each entity is frozen, this routine is called to deal with the
184 -- setting of Debug_Info_Needed for the entity. This flag is set if
185 -- the entity comes from source, or if we are in Debug_Generated_Code
186 -- mode or if the -gnatdV debug flag is set. However, it never sets
187 -- the flag if Debug_Info_Off is set. This procedure also ensures that
188 -- subsidiary entities have the flag set as required.
191 -- T is a record or array type that is being frozen. If it is a base type,
192 -- and if SSO_Set_Low/High_By_Default is set, then Reverse_Storage order
193 -- will be set appropriately. Note that an explicit occurrence of aspect
194 -- Scalar_Storage_Order or an explicit setting of this aspect with an
195 -- attribute definition clause occurs, then these two flags are reset in
196 -- any case, so call will have no effect.
199 -- T is a type of a component that we know to be an Itype. We don't want
200 -- this to have a Freeze_Node, so ensure it doesn't. Do the same for any
201 -- Full_View or Corresponding_Record_Type.
203 procedure Warn_Overlay
207 -- Expr is the expression for an address clause for entity Nam whose type
208 -- is Typ. If Typ has a default initialization, and there is no explicit
209 -- initialization in the source declaration, check whether the address
210 -- clause might cause overlaying of an entity, and emit a warning on the
211 -- side effect that the initialization will cause.
213 -------------------------------
214 -- Adjust_Esize_For_Alignment --
215 -------------------------------
220 begin
226 then
232 ------------------------------------
233 -- Build_And_Analyze_Renamed_Body --
234 ------------------------------------
236 procedure Build_And_Analyze_Renamed_Body
240 is
246 begin
247 -- If the renamed subprogram is intrinsic, there is no need for a
248 -- wrapper body: we set the alias that will be called and expanded which
249 -- completes the declaration. This transformation is only legal if the
250 -- renamed entity has already been elaborated.
252 -- Note that it is legal for a renaming_as_body to rename an intrinsic
253 -- subprogram, as long as the renaming occurs before the new entity
254 -- is frozen (RM 8.5.4 (5)).
258 then
260 else
266 and then
270 -- We can make the renaming entity intrinsic if the renamed function
271 -- has an interface name, or if it is one of the shift/rotate
272 -- operations known to the compiler.
274 and then
277 Name_Rotate_Right,
278 Name_Shift_Left,
279 Name_Shift_Right,
280 Name_Shift_Right_Arithmetic))
281 then
286 else
293 else
302 ------------------------
303 -- Build_Renamed_Body --
304 ------------------------
306 function Build_Renamed_Body
309 is
311 -- We use for the source location of the renamed body, the location of
312 -- the spec entity. It might seem more natural to use the location of
313 -- the renaming declaration itself, but that would be wrong, since then
314 -- the body we create would look as though it was created far too late,
315 -- and this could cause problems with elaboration order analysis,
316 -- particularly in connection with instantiations.
331 -- If the renamed entity is a primitive operation given in prefix form,
332 -- the prefix is the target object and it has to be added as the first
333 -- actual in the generated call.
335 begin
336 -- Determine the entity being renamed, which is the target of the call
337 -- statement. If the name is an explicit dereference, this is a renaming
338 -- of a subprogram type rather than a subprogram. The name itself is
339 -- fully analyzed.
350 else
357 else
363 -- If the renamed entity is a predefined operator, retain full name
364 -- to ensure its visibility.
368 then
370 else
374 else
377 and then
380 then
382 -- Retrieve the target object, to be added as a first actual
383 -- in the call.
388 else
392 -- Original name may have been overloaded, but is fully resolved now
397 -- For simple renamings, subsequent calls can be expanded directly as
398 -- calls to the renamed entity. The body must be generated in any case
399 -- for calls that may appear elsewhere. This is not done in the case
400 -- where the subprogram is an instantiation because the actual proper
401 -- body has not been built yet.
406 then
410 -- The body generated for this renaming is an internal artifact, and
411 -- does not constitute a freeze point for the called entity.
418 declare
422 begin
423 -- The controlling formal may be an access parameter, or the
424 -- actual may be an access value, so adjust accordingly.
428 then
429 Actuals := New_List
434 then
435 Actuals := New_List
439 else
447 else
458 -- If the renamed entity is an entry, inherit its profile. For other
459 -- renamings as bodies, both profiles must be subtype conformant, so it
460 -- is not necessary to replace the profile given in the declaration.
461 -- However, default values that are aggregates are rewritten when
462 -- partially analyzed, so we recover the original aggregate to insure
463 -- that subsequent conformity checking works. Similarly, if the default
464 -- expression was constant-folded, recover the original expression.
474 N_Access_Definition
475 then
483 then
494 -- If the renamed entity is a function, the generated body contains a
495 -- return statement. Otherwise, build a procedure call. If the entity is
496 -- an entry, subsequent analysis of the call will transform it into the
497 -- proper entry or protected operation call. If the renamed entity is
498 -- a character literal, return it directly.
504 then
505 Call_Node :=
507 Expression =>
513 Call_Node :=
518 Call_Node :=
522 else
523 Call_Node :=
529 -- Create entities for subprogram body and formals
542 Body_Node :=
546 Handled_Statement_Sequence =>
556 -- Link the body to the entity whose declaration it completes. If
557 -- the body is analyzed when the renamed entity is frozen, it may
558 -- be necessary to restore the proper scope (see package Exp_Ch13).
562 then
564 else
571 --------------------------
572 -- Check_Address_Clause --
573 --------------------------
582 begin
589 -- Has_Delayed_Freeze was set on E when the address clause was
590 -- analyzed, and must remain set because we want the address
591 -- clause to be elaborated only after any entity it references
592 -- has been elaborated.
595 -- If Rep_Clauses are to be ignored, remove address clause from
596 -- list attached to entity, because it may be illegal for gigi,
597 -- for example by breaking order of elaboration..
600 declare
603 begin
609 else
612 loop
622 -- And now remove the address clause
628 then
634 -- Capture initialization value at point of declaration
638 -- Move initialization to freeze actions (once the object has
639 -- been frozen, and the address clause alignment check has been
640 -- performed.
652 -----------------------------
653 -- Check_Compile_Time_Size --
654 -----------------------------
659 -- Sets the compile time known size (32 bits or less) in the Esize
660 -- field, of T checking for a size clause that was given which attempts
661 -- to give a smaller size, and also checking for an alignment clause.
664 -- Recursive function that does all the work
667 -- If T is a constrained subtype, its size is not known if any of its
668 -- discriminant constraints is not static and it is not a null record.
669 -- The test is conservative and doesn't check that the components are
670 -- in fact constrained by non-static discriminant values. Could be made
671 -- more precise ???
673 --------------------
674 -- Set_Small_Size --
675 --------------------
678 begin
682 -- Check for bad size clause given
687 Error_Msg_NE
692 -- Set size if not set already
699 ----------------
700 -- Size_Known --
701 ----------------
710 begin
714 -- Always True for scalar types. This is true even for generic formal
715 -- scalar types. We used to return False in the latter case, but the
716 -- size is known at compile time, even in the template, we just do
717 -- not know the exact size but that's not the point of this routine.
721 then
724 -- Array types
728 -- String literals always have known size, and we can set it
735 -- Unconstrained types never have known at compile time size
740 -- Don't do any recursion on type with error posted, since we may
741 -- have a malformed type that leads us into a loop.
746 -- Otherwise if component size unknown, then array size unknown
752 -- Check for all indexes static, and also compute possible size
753 -- (in case it is less than 32 and may be packable).
755 declare
759 begin
768 else
776 then
779 else
784 else
796 -- Access types always have known at compile time sizes
801 -- For non-generic private types, go to underlying type if present
806 then
807 -- Don't do any recursion on type with error posted, since we may
808 -- have a malformed type that leads us into a loop.
812 else
816 -- Record types
820 -- A class-wide type is never considered to have a known size
825 -- A subtype of a variant record must not have non-static
826 -- discriminated components.
830 then
833 -- Don't do any recursion on type with error posted, since we may
834 -- have a malformed type that leads us into a loop.
840 -- Now look at the components of the record
842 declare
843 -- The following two variables are used to keep track of the
844 -- size of packed records if we can tell the size of the packed
845 -- record in the front end. Packed_Size_Known is True if so far
846 -- we can figure out the size. It is initialized to True for a
847 -- packed record, unless the record has discriminants or atomic
848 -- components or independent components.
850 -- The reason we eliminate the discriminated case is that
851 -- we don't know the way the back end lays out discriminated
852 -- packed records. If Packed_Size_Known is True, then
853 -- Packed_Size is the size in bits so far.
862 -- Size in bits so far
864 begin
865 -- Test for variant part present
871 N_Record_Definition
873 and then
874 Present (Variant_Part
876 then
877 -- If variant part is present, and type is unconstrained,
878 -- then we must have defaulted discriminants, or a size
879 -- clause must be present for the type, or else the size
880 -- is definitely not known at compile time.
883 and then
886 then
891 -- Loop through components
897 -- We do not know the packed size if there is a component
898 -- clause present (we possibly could, but this would only
899 -- help in the case of a record with partial rep clauses.
900 -- That's because in the case of full rep clauses, the
901 -- size gets figured out anyway by a different circuit).
907 -- We do not know the packed size if we have a by reference
908 -- type, or an atomic type or an atomic component, or an
909 -- aliased component (because packing does not touch these).
915 then
919 -- We need to identify a component that is an array where
920 -- the index type is an enumeration type with non-standard
921 -- representation, and some bound of the type depends on a
922 -- discriminant.
924 -- This is because gigi computes the size by doing a
925 -- substitution of the appropriate discriminant value in
926 -- the size expression for the base type, and gigi is not
927 -- clever enough to evaluate the resulting expression (which
928 -- involves a call to rep_to_pos) at compile time.
930 -- It would be nice if gigi would either recognize that
931 -- this expression can be computed at compile time, or
932 -- alternatively figured out the size from the subtype
933 -- directly, where all the information is at hand ???
937 then
938 declare
946 begin
953 then
959 then
964 then
974 -- Clearly size of record is not known if the size of one of
975 -- the components is not known.
981 -- Accumulate packed size if possible
985 -- We can only deal with elementary types, since for
986 -- non-elementary components, alignment enters into the
987 -- picture, and we don't know enough to handle proper
988 -- alignment in this context. Packed arrays count as
989 -- elementary if the representation is a modular type.
993 and then Present
995 and then Is_Modular_Integer_Type
997 then
998 -- Packed size unknown if we have an atomic type
999 -- or a by reference type, since the back end
1000 -- knows how these are layed out.
1004 then
1007 -- If RM_Size is known and static, then we can keep
1008 -- accumulating the packed size
1012 -- A little glitch, to be removed sometime ???
1013 -- gigi does not understand zero sizes yet.
1018 -- Normal case where we can keep accumulating the
1019 -- packed array size.
1021 else
1025 -- If we have a field whose RM_Size is not known then
1026 -- we can't figure out the packed size here.
1028 else
1032 -- If we have a non-elementary type we can't figure out
1033 -- the packed array size (alignment issues).
1035 else
1050 -- All other cases, size not known at compile time
1052 else
1057 -------------------------------------
1058 -- Static_Discriminated_Components --
1059 -------------------------------------
1061 function Static_Discriminated_Components
1063 is
1066 begin
1070 then
1084 -- Start of processing for Check_Compile_Time_Size
1086 begin
1090 -----------------------------------
1091 -- Check_Component_Storage_Order --
1092 -----------------------------------
1094 procedure Check_Component_Storage_Order
1099 is
1105 -- Set for the record case, True if Comp starts on a byte boundary
1106 -- (in which case it is allowed to have different storage order).
1109 -- Set True when the component is a nested composite, and it does not
1110 -- have the same scalar storage order as Encl_Type.
1114 begin
1115 -- Record case
1125 else
1126 -- If a component clause is present, check if the component starts
1127 -- on a storage element boundary. Otherwise conservatively assume
1128 -- it does so only in the case where the record is not packed.
1131 Comp_Byte_Aligned :=
1133 else
1140 -- Array case
1142 else
1149 -- Note: the Reverse_Storage_Order flag is set on the base type, but
1150 -- the attribute definition clause is attached to the first subtype.
1153 Comp_ADC := Get_Attribute_Definition_Clause
1155 Attribute_Scalar_Storage_Order);
1158 -- Case of record or array component: check storage order compatibility
1161 Comp_SSO_Differs :=
1163 /=
1166 -- Parent and extension must have same storage order
1170 Error_Msg_N
1175 -- If enclosing composite has explicit SSO then nested composite must
1176 -- have explicit SSO as well.
1182 -- If component and composite SSO differs, check that component
1183 -- falls on byte boundaries and isn't packed.
1187 -- Component SSO differs from enclosing composite:
1189 -- Reject if component is a packed array, as it may be represented
1190 -- as a scalar internally.
1193 Error_Msg_N
1197 -- Reject if composite is a packed array, as it may be rewritten
1198 -- into an array of scalars.
1204 -- Reject if not byte aligned
1207 and then not Comp_Byte_Aligned
1208 then
1209 Error_Msg_N
1215 -- Enclosing type has explicit SSO: non-composite component must not
1216 -- be aliased.
1219 Error_Msg_N
1225 -----------------------------
1226 -- Check_Debug_Info_Needed --
1227 -----------------------------
1230 begin
1235 or else Debug_Generated_Code
1236 or else Debug_Flag_VV
1238 then
1243 -------------------------------
1244 -- Check_Expression_Function --
1245 -------------------------------
1251 -- Function to search for deferred constant
1253 -------------------
1254 -- Find_Constant --
1255 -------------------
1258 begin
1259 -- When a constant is initialized with the result of a dispatching
1260 -- call, the constant declaration is rewritten as a renaming of the
1261 -- displaced function result. This scenario is not a premature use of
1262 -- a constant even though the Has_Completion flag is not set.
1269 N_Object_Declaration
1272 then
1273 Error_Msg_NE
1282 -- Start of processing for Check_Expression_Function
1284 begin
1289 then
1294 ----------------------------
1295 -- Check_Strict_Alignment --
1296 ----------------------------
1301 begin
1319 then
1329 -------------------------
1330 -- Check_Unsigned_Type --
1331 -------------------------
1338 begin
1343 -- Do not attempt to analyze case where range was in error
1349 -- The situation that is non trivial is something like
1351 -- subtype x1 is integer range -10 .. +10;
1352 -- subtype x2 is x1 range 0 .. V1;
1353 -- subtype x3 is x2 range V2 .. V3;
1354 -- subtype x4 is x3 range V4 .. V5;
1356 -- where Vn are variables. Here the base type is signed, but we still
1357 -- know that x4 is unsigned because of the lower bound of x2.
1359 -- The only way to deal with this is to look up the ancestor chain
1362 loop
1376 else
1379 -- If no ancestor had a static lower bound, go to base type
1383 -- Note: the reason we still check for a compile time known
1384 -- value for the base type is that at least in the case of
1385 -- generic formals, we can have bounds that fail this test,
1386 -- and there may be other cases in error situations.
1398 then
1408 -------------------------
1409 -- Is_Atomic_Aggregate --
1410 -------------------------
1412 function Is_Atomic_Aggregate
1415 is
1421 begin
1424 -- Array may be qualified, so find outer context
1432 then
1434 New_N :=
1445 else
1450 -----------------------------------------------
1451 -- Explode_Initialization_Compound_Statement --
1452 -----------------------------------------------
1457 begin
1460 then
1463 -- Note that we rewrite Init_Stmts into a NULL statement, rather than
1464 -- just removing it, because Freeze_All may rely on this particular
1465 -- Node_Id still being present in the enclosing list to know where to
1466 -- stop freezing.
1474 ----------------
1475 -- Freeze_All --
1476 ----------------
1478 -- Note: the easy coding for this procedure would be to just build a
1479 -- single list of freeze nodes and then insert them and analyze them
1480 -- all at once. This won't work, because the analysis of earlier freeze
1481 -- nodes may recursively freeze types which would otherwise appear later
1482 -- on in the freeze list. So we must analyze and expand the freeze nodes
1483 -- as they are generated.
1490 -- This is the internal recursive routine that does freezing of entities
1491 -- (but NOT the analysis of default expressions, which should not be
1492 -- recursive, we don't want to analyze those till we are sure that ALL
1493 -- the types are frozen).
1495 --------------------
1496 -- Freeze_All_Ent --
1497 --------------------
1505 -- If freeze nodes are present, insert and analyze, and reset cursor
1506 -- for next insertion.
1508 -------------------
1509 -- Process_Flist --
1510 -------------------
1513 begin
1520 else
1526 -- Start or processing for Freeze_All_Ent
1528 begin
1532 -- If the entity is an inner package which is not a package
1533 -- renaming, then its entities must be frozen at this point. Note
1534 -- that such entities do NOT get frozen at the end of the nested
1535 -- package itself (only library packages freeze).
1537 -- Same is true for task declarations, where anonymous records
1538 -- created for entry parameters must be frozen.
1544 then
1555 then
1562 N_Single_Task_Declaration)
1563 then
1566 End_Scope;
1568 -- For a derived tagged type, we must ensure that all the
1569 -- primitive operations of the parent have been frozen, so that
1570 -- their addresses will be in the parent's dispatch table at the
1571 -- point it is inherited.
1577 then
1578 declare
1585 begin
1592 then
1594 Process_Flist;
1604 Process_Flist;
1606 -- If already frozen, and there are delayed aspects, this is where
1607 -- we do the visibility check for these aspects (see Sem_Ch13 spec
1608 -- for a description of how we handle aspect visibility).
1612 -- Retrieve the visibility to the discriminants in order to
1613 -- analyze properly the aspects.
1617 declare
1620 begin
1626 then
1637 -- If an incomplete type is still not frozen, this may be a
1638 -- premature freezing because of a body declaration that follows.
1639 -- Indicate where the freezing took place. Freezing will happen
1640 -- if the body comes from source, but not if it is internally
1641 -- generated, for example as the body of a type invariant.
1643 -- If the freezing is caused by the end of the current declarative
1644 -- part, it is a Taft Amendment type, and there is no error.
1648 then
1649 declare
1652 begin
1653 -- The presence of a body freezes all entities previously
1654 -- declared in the current list of declarations, but this
1655 -- does not apply if the body does not come from source.
1656 -- A type invariant is transformed into a subprogram body
1657 -- which is placed at the end of the private part of the
1658 -- current package, but this body does not freeze incomplete
1659 -- types that may be declared in this private part.
1662 N_Entry_Body,
1663 N_Package_Body,
1664 N_Protected_Body,
1665 N_Task_Body)
1667 and then
1670 then
1672 Error_Msg_NE
1683 -- Start of processing for Freeze_All
1685 begin
1688 -- Now that all types are frozen, we can deal with default expressions
1689 -- that require us to build a default expression functions. This is the
1690 -- point at which such functions are constructed (after all types that
1691 -- might be used in such expressions have been frozen).
1693 -- For subprograms that are renaming_as_body, we create the wrapper
1694 -- bodies as needed.
1696 -- We also add finalization chains to access types whose designated
1697 -- types are controlled. This is normally done when freezing the type,
1698 -- but this misses recursive type definitions where the later members
1699 -- of the recursion introduce controlled components.
1701 -- Loop through entities
1717 else
1723 and then
1725 = N_Subprogram_Renaming_Declaration
1726 then
1727 Build_And_Analyze_Renamed_Body
1734 N_Single_Task_Declaration)
1735 then
1736 declare
1739 begin
1744 then
1752 -- We add finalization masters to access types whose designated types
1753 -- require finalization. This is normally done when freezing the
1754 -- type, but this misses recursive type definitions where the later
1755 -- members of the recursion introduce controlled components (such as
1756 -- can happen when incomplete types are involved), as well cases
1757 -- where a component type is private and the controlled full type
1758 -- occurs after the access type is frozen. Cases that don't need a
1759 -- finalization master are generic formal types (the actual type will
1760 -- have it) and types derived from them, and types with Java and CIL
1761 -- conventions, since those are used for API bindings.
1762 -- (Are there any other cases that should be excluded here???)
1768 then
1776 -----------------------
1777 -- Freeze_And_Append --
1778 -----------------------
1780 procedure Freeze_And_Append
1784 is
1786 begin
1790 else
1796 -------------------
1797 -- Freeze_Before --
1798 -------------------
1803 begin
1813 -------------------
1814 -- Freeze_Entity --
1815 -------------------
1826 -- This could use a comment ???
1829 -- Used to detect attempt to freeze function declared in another unit
1832 -- List of freezing actions, left at No_List if none
1835 -- This flag gets set to true for a variable with default initialization
1838 -- N is a freezing action to be appended to the Result
1841 -- If Loc is a freeze_entity that appears after the last declaration
1842 -- in the scope, inhibit error messages on late completion.
1845 -- Check that an Access or Unchecked_Access attribute with a prefix
1846 -- which is the current instance type can only be applied when the type
1847 -- is limited.
1850 -- Give warning for modulus of 8, 16, 32, or 64 given as an explicit
1851 -- integer literal without an explicit corresponding size clause. The
1852 -- caller has checked that Utype is a modular integer type.
1855 -- Freeze array type, including freezing index and component types
1858 -- Create Freeze_Generic_Entity nodes for types declared in a generic
1859 -- package. Recurse on inner generic packages.
1862 -- Freeze record type, including freezing component types, and freezing
1863 -- primitive operations if this is a tagged type.
1866 -- Determine whether an arbitrary entity is subject to Boolean aspect
1867 -- Import and its value is specified as True.
1870 -- Following AI05-151, a function can return a limited view of a type
1871 -- declared elsewhere. In that case the function cannot be frozen at
1872 -- the end of its enclosing package. If its first use is in a different
1873 -- unit, it cannot be frozen there, but if the call is legal the full
1874 -- view of the return type is available and the subprogram can now be
1875 -- frozen. However the freeze node cannot be inserted at the point of
1876 -- call, but rather must go in the package holding the function, so that
1877 -- the backend can process it in the proper context.
1880 -- If E is an entity for an imported subprogram with pre/post-conditions
1881 -- then this procedure will create a wrapper to ensure that proper run-
1882 -- time checking of the pre/postconditions. See body for details.
1884 -------------------
1885 -- Add_To_Result --
1886 -------------------
1889 begin
1892 else
1897 ----------------------------
1898 -- After_Last_Declaration --
1899 ----------------------------
1904 begin
1910 else
1914 else
1919 ----------------------------
1920 -- Check_Current_Instance --
1921 ----------------------------
1926 -- Determine whether Typ is compatible with the rules for aliased
1927 -- views of types as defined in RM 3.10 in the various dialects.
1930 -- Process routine to apply check to given node
1932 -----------------------------
1933 -- Is_Aliased_View_Of_Type --
1934 -----------------------------
1939 begin
1940 -- Common case
1944 then
1947 -- The following paragraphs describe what a legal aliased view of
1948 -- a type is in the various dialects of Ada.
1950 -- Ada 95
1952 -- The current instance of a limited type, and a formal parameter
1953 -- or generic formal object of a tagged type.
1955 -- Ada 95 limited type
1956 -- * Type with reserved word "limited"
1957 -- * A protected or task type
1958 -- * A composite type with limited component
1963 -- Ada 2005
1965 -- The current instance of a limited tagged type, a protected
1966 -- type, a task type, or a type that has the reserved word
1967 -- "limited" in its full definition ... a formal parameter or
1968 -- generic formal object of a tagged type.
1970 -- Ada 2005 limited type
1971 -- * Type with reserved word "limited", "synchronized", "task"
1972 -- or "protected"
1973 -- * A composite type with limited component
1974 -- * A derived type whose parent is a non-interface limited type
1977 return
1979 or else
1984 -- Ada 2012 and beyond
1986 -- The current instance of an immutably limited type ... a formal
1987 -- parameter or generic formal object of a tagged type.
1989 -- Ada 2012 limited type
1990 -- * Type with reserved word "limited", "synchronized", "task"
1991 -- or "protected"
1992 -- * A composite type with limited component
1993 -- * A derived type whose parent is a non-interface limited type
1994 -- * An incomplete view
1996 -- Ada 2012 immutably limited type
1997 -- * Explicitly limited record type
1998 -- * Record extension with "limited" present
1999 -- * Non-formal limited private type that is either tagged
2000 -- or has at least one access discriminant with a default
2001 -- expression
2002 -- * Task type, protected type or synchronized interface
2003 -- * Type derived from immutably limited type
2005 else
2006 return
2012 -------------
2013 -- Process --
2014 -------------
2017 begin
2021 Name_Unchecked_Access)
2025 then
2027 Error_Msg_N
2030 else
2031 Error_Msg_N
2038 else
2048 -- Local variables
2053 -- Start of processing for Check_Current_Instance
2055 begin
2061 ------------------------------
2062 -- Check_Suspicious_Modulus --
2063 ------------------------------
2068 begin
2074 declare
2077 begin
2079 declare
2083 begin
2085 declare
2089 begin
2090 -- First case, modulus and size are the same. This
2091 -- happens if you have something like mod 32, with
2092 -- an explicit size of 32, this is for sure a case
2093 -- where the warning is given, since it is seems
2094 -- very unlikely that someone would want e.g. a
2095 -- five bit type stored in 32 bits. It is much
2096 -- more likely they wanted a 32-bit type.
2101 -- Second case, the modulus is 32 or 64 and no
2102 -- size clause is present. This is a less clear
2103 -- case for giving the warning, but in the case
2104 -- of 32/64 (5-bit or 6-bit types) these seem rare
2105 -- enough that it is a likely error (and in any
2106 -- case using 2**5 or 2**6 in these cases seems
2107 -- clearer. We don't include 8 or 16 here, simply
2108 -- because in practice 3-bit and 4-bit types are
2109 -- more common and too many false positives if
2110 -- we warn in these cases.
2114 then
2117 -- No warning needed
2119 else
2123 -- If we fall through, give warning
2126 Error_Msg_N
2128 Modulus);
2137 -----------------------
2138 -- Freeze_Array_Type --
2139 -----------------------
2147 -- Set true if any of the index types is an enumeration type with a
2148 -- non-standard representation.
2150 begin
2159 then
2166 -- Processing that is done only for base types
2170 -- Deal with default setting of reverse storage order
2174 -- Propagate flags for component type
2178 then
2186 -- Warn for pragma Pack overriding foreign convention
2190 then
2191 declare
2196 begin
2200 Error_Msg_N
2203 Error_Msg_N
2210 -- If packing was requested or if the component size was
2211 -- set explicitly, then see if bit packing is required. This
2212 -- processing is only done for base types, since all of the
2213 -- representation aspects involved are type-related.
2215 -- This is not just an optimization, if we start processing the
2216 -- subtypes, they interfere with the settings on the base type
2217 -- (this is because Is_Packed has a slightly different meaning
2218 -- before and after freezing).
2220 declare
2224 begin
2228 then
2237 else
2240 -- We can set the component size if it is less than 16,
2241 -- rounding it up to the next storage unit size.
2247 else
2251 -- Set component size up to match alignment if it would
2252 -- otherwise be less than the alignment. This deals with
2253 -- cases of types whose alignment exceeds their size (the
2254 -- padded type cases).
2257 declare
2259 begin
2267 -- Case of component size that may result in packing
2270 declare
2276 Get_Attribute_Definition_Clause
2279 begin
2280 -- Warn if we have pack and component size so that the
2281 -- pack is ignored.
2283 -- Note: here we must check for the presence of a
2284 -- component size before checking for a Pack pragma to
2285 -- deal with the case where the array type is a derived
2286 -- type whose parent is currently private.
2290 and then Warn_On_Redundant_Constructs
2291 then
2293 Error_Msg_NE
2295 Error_Msg_N
2301 -- Set component size if not already set by a component
2302 -- size clause.
2308 -- Check for base type of 8, 16, 32 bits, where an
2309 -- unsigned subtype has a length one less than the
2310 -- base type (e.g. Natural subtype of Integer).
2312 -- In such cases, if a component size was not set
2313 -- explicitly, then generate a warning.
2319 then
2323 Error_Msg_N
2325 Pack_Pragma);
2326 Error_Msg_N
2328 Pack_Pragma);
2332 -- Actual packing is not needed for 8, 16, 32, 64. Also
2333 -- not needed for 24 if alignment is 1.
2340 then
2341 -- Here the array was requested to be packed, but
2342 -- the packing request had no effect, so Is_Packed
2343 -- is reset.
2345 -- Note: semantically this means that we lose track
2346 -- of the fact that a derived type inherited a pragma
2347 -- Pack that was non- effective, but that seems fine.
2349 -- We regard a Pack pragma as a request to set a
2350 -- representation characteristic, and this request
2351 -- may be ignored.
2358 then
2362 -- In all other cases, packing is indeed needed
2364 else
2373 -- Check for Atomic_Components or Aliased with unsuitable packing
2374 -- or explicit component size clause given.
2377 or else
2379 and then
2381 then
2385 -- Outputs error messages for incorrect CS clause or pragma
2386 -- Pack for aliased or atomic components (T is "aliased" or
2387 -- "atomic");
2389 -----------------
2390 -- Complain_CS --
2391 -----------------
2394 begin
2396 Clause :=
2397 Get_Attribute_Definition_Clause
2401 Error_Msg_N
2405 Error_Msg_N
2408 else
2409 Error_Msg_N
2414 else
2415 Error_Msg_N
2423 -- Start of processing for Alias_Atomic_Check
2425 begin
2426 -- If object size of component type isn't known, we cannot
2427 -- be sure so we defer to the back end.
2432 -- Case where component size has no effect. First check for
2433 -- object size of component type multiple of the storage
2434 -- unit size.
2438 -- OK in both packing case and component size case if RM
2439 -- size is known and static and same as the object size.
2441 and then
2445 -- Or if we have an explicit component size clause and
2446 -- the component size and object size are equal.
2448 or else
2451 then
2456 then
2461 then
2467 -- Warn for case of atomic type
2473 then
2474 Error_Msg_NE
2489 -- Check for scalar storage order
2491 declare
2493 begin
2494 Check_Component_Storage_Order
2497 ADC => Get_Attribute_Definition_Clause
2499 Attribute_Scalar_Storage_Order),
2503 -- Processing that is done only for subtypes
2505 else
2506 -- Acquire alignment from base type
2514 -- Specific checks for bit-packed arrays
2518 -- Check number of elements for bit packed arrays that come from
2519 -- source and have compile time known ranges. The bit-packed
2520 -- arrays circuitry does not support arrays with more than
2521 -- Integer'Last + 1 elements, and when this restriction is
2522 -- violated, causes incorrect data access.
2524 -- For the case where this is not compile time known, a run-time
2525 -- check should be generated???
2528 declare
2534 begin
2540 -- Never generate an error if any index is of a generic
2541 -- type. We will check this in instances.
2548 Ilen :=
2554 -- No attempt is made to check number of elements
2555 -- if not compile time known.
2568 then
2569 Error_Msg_N
2576 -- Check size
2579 declare
2583 begin
2584 -- It is not clear if it is possible to have no size clause
2585 -- at this stage, but it is not worth worrying about. Post
2586 -- error on the entity name in the size clause if present,
2587 -- else on the type entity itself.
2591 else
2598 -- If any of the index types was an enumeration type with a
2599 -- non-standard rep clause, then we indicate that the array type
2600 -- is always packed (even if it is not bit packed).
2609 -- If the array is packed, we must create the packed array type to be
2610 -- used to actually implement the type. This is only needed for real
2611 -- array types (not for string literal types, since they are present
2612 -- only for the front end).
2616 then
2620 -- Size information of packed array type is copied to the array
2621 -- type, since this is really the representation. But do not
2622 -- override explicit existing size values. If the ancestor subtype
2623 -- is constrained the Packed_Array_Impl_Type will be inherited
2624 -- from it, but the size may have been provided already, and
2625 -- must not be overridden either.
2628 and then
2631 then
2641 -- For non-packed arrays set the alignment of the array to the
2642 -- alignment of the component type if it is unknown. Skip this
2643 -- in atomic case (atomic arrays may need larger alignments).
2652 then
2657 -----------------------------
2658 -- Freeze_Generic_Entities --
2659 -----------------------------
2666 begin
2685 ------------------------
2686 -- Freeze_Record_Type --
2687 ------------------------
2699 -- Set True if the record type scope Rec has been pushed on the scope
2700 -- stack. Needed for the analysis of delayed aspects specified to the
2701 -- components of Rec.
2704 -- Scalar_Storage_Order attribute definition clause for the record
2707 -- Set True if we find at least one component with no component
2708 -- clause (used to warn about useless Pack pragmas).
2711 -- Set True if we find at least one component with a component
2712 -- clause (used to warn about useless Bit_Order pragmas, and also
2713 -- to detect cases where Implicit_Packing may have an effect).
2716 -- Set True if we find at least one component which is aliased. This
2717 -- is used to prevent Implicit_Packing of the record, since packing
2718 -- cannot modify the size of alignment of an aliased component.
2721 -- Set True if we find at least one component whose type has a
2722 -- Scalar_Storage_Order attribute definition clause.
2725 -- Set False if we encounter a component of a non-scalar type
2729 -- Accumulates total RM_Size values and total Esize values of all
2730 -- scalar components. Used for processing of Implicit_Packing.
2733 -- If N is an allocator, possibly wrapped in one or more level of
2734 -- qualified expression(s), return the inner allocator node, else
2735 -- return Empty.
2738 -- If the component subtype is an access to a constrained subtype of
2739 -- an already frozen type, make the subtype frozen as well. It might
2740 -- otherwise be frozen in the wrong scope, and a freeze node on
2741 -- subtype has no effect. Similarly, if the component subtype is a
2742 -- regular (not protected) access to subprogram, set the anonymous
2743 -- subprogram type to frozen as well, to prevent an out-of-scope
2744 -- freeze node at some eventual point of call. Protected operations
2745 -- are handled elsewhere.
2748 -- Make sure that all types mentioned in Discrete_Choices of the
2749 -- variants referenceed by the Variant_Part VP are frozen. This is
2750 -- a recursive routine to deal with nested variants.
2752 ---------------------
2753 -- Check_Allocator --
2754 ---------------------
2758 begin
2760 loop
2765 else
2771 -----------------
2772 -- Check_Itype --
2773 -----------------
2778 begin
2781 then
2784 -- In addition, add an Itype_Reference to ensure that the
2785 -- access subtype is elaborated early enough. This cannot be
2786 -- done if the subtype may depend on discriminants.
2791 then
2799 then
2804 ------------------------------------
2805 -- Freeze_Choices_In_Variant_Part --
2806 ------------------------------------
2815 begin
2816 -- Loop through variants
2821 -- Loop through choices, checking that all types are frozen
2827 then
2834 -- Check for nested variant part to process
2848 -- Start of processing for Freeze_Record_Type
2850 begin
2851 -- Deal with delayed aspect specifications for components. The
2852 -- analysis of the aspect is required to be delayed to the freeze
2853 -- point, thus we analyze the pragma or attribute definition
2854 -- clause in the tree at this point. We also analyze the aspect
2855 -- specification node at the freeze point when the aspect doesn't
2856 -- correspond to pragma/attribute definition clause.
2862 then
2867 -- The visibility to the discriminants must be restored in
2868 -- order to properly analyze the aspects.
2881 -- Pop the scope if Rec scope has been pushed on the scope stack
2882 -- during the delayed aspect analysis process.
2889 Pop_Scope;
2892 -- Freeze components and embedded subtypes
2901 -- Handle the component and discriminant case
2904 declare
2907 begin
2908 -- Freezing a record type freezes the type of each of its
2909 -- components. However, if the type of the component is
2910 -- part of this record, we do not want or need a separate
2911 -- Freeze_Node. Note that Is_Itype is wrong because that's
2912 -- also set in private type cases. We also can't check for
2913 -- the Scope being exactly Rec because of private types and
2914 -- record extensions.
2919 then
2925 -- Warn for pragma Pack overriding foreign convention
2930 -- Don't warn for aliased components, since override
2931 -- cannot happen in that case.
2934 then
2935 declare
2940 begin
2944 Error_Msg_N
2946 PP);
2948 Error_Msg_NE
2955 -- Check for error of component clause given for variable
2956 -- sized type. We have to delay this test till this point,
2957 -- since the component type has to be frozen for us to know
2958 -- if it is variable length.
2963 -- We omit this test in a generic context, it will be
2964 -- applied at instantiation time.
2969 -- Also omit this test in CodePeer mode, since we do not
2970 -- have sufficient info on size and rep clauses.
2975 -- Do the check
2977 elsif not
2978 Size_Known_At_Compile_Time
2980 then
2981 Error_Msg_N
2986 else
2990 -- Case of component requires byte alignment
2994 -- Set the enclosing record to also require byte align
2998 -- Check for component clause that is inconsistent with
2999 -- the required byte boundary alignment.
3004 then
3005 Error_Msg_N
3013 -- Gather data for possible Implicit_Packing later. Note that at
3014 -- this stage we might be dealing with a real component, or with
3015 -- an implicit subtype declaration.
3019 else
3020 Scalar_Component_Total_RM_Size :=
3022 Scalar_Component_Total_Esize :=
3026 -- If the component is an Itype with Delayed_Freeze and is either
3027 -- a record or array subtype and its base type has not yet been
3028 -- frozen, we must remove this from the entity list of this record
3029 -- and put it on the entity list of the scope of its base type.
3030 -- Note that we know that this is not the type of a component
3031 -- since we cleared Has_Delayed_Freeze for it in the previous
3032 -- loop. Thus this must be the Designated_Type of an access type,
3033 -- which is the type of a component.
3041 then
3042 declare
3046 begin
3047 -- We have a difficult case to handle here. Suppose Rec is
3048 -- subtype being defined in a subprogram that's created as
3049 -- part of the freezing of Rec'Base. In that case, we know
3050 -- that Comp'Base must have already been frozen by the time
3051 -- we get to elaborate this because Gigi doesn't elaborate
3052 -- any bodies until it has elaborated all of the declarative
3053 -- part. But Is_Frozen will not be set at this point because
3054 -- we are processing code in lexical order.
3056 -- We detect this case by going up the Scope chain of Rec
3057 -- and seeing if we have a subprogram scope before reaching
3058 -- the top of the scope chain or that of Comp'Base. If we
3059 -- do, then mark that Comp'Base will actually be frozen. If
3060 -- so, we merely undelay it.
3077 else
3080 else
3084 -- Insert in entity list of scope of base type (which
3085 -- must be an enclosing scope, because still unfrozen).
3091 -- If the component is an access type with an allocator as default
3092 -- value, the designated type will be frozen by the corresponding
3093 -- expression in init_proc. In order to place the freeze node for
3094 -- the designated type before that for the current record type,
3095 -- freeze it now.
3097 -- Same process if the component is an array of access types,
3098 -- initialized with an aggregate. If the designated type is
3099 -- private, it cannot contain allocators, and it is premature
3100 -- to freeze the type, so we check for this as well.
3105 then
3106 declare
3110 begin
3113 -- If component is pointer to a class-wide type, freeze
3114 -- the specific type in the expression being allocated.
3115 -- The expression may be a subtype indication, in which
3116 -- case freeze the subtype mark.
3118 if Is_Class_Wide_Type
3120 then
3122 Freeze_And_Append
3126 then
3127 Freeze_And_Append
3135 else
3136 Freeze_And_Append
3144 then
3147 -- Freeze the designated type when initializing a component with
3148 -- an aggregate in case the aggregate contains allocators.
3150 -- type T is ...;
3151 -- type T_Ptr is access all T;
3152 -- type T_Array is array ... of T_Ptr;
3154 -- type Rec is record
3155 -- Comp : T_Array := (others => ...);
3156 -- end record;
3160 then
3161 declare
3164 Designated_Type
3167 begin
3168 -- The only case when this sort of freezing is not done is
3169 -- when the designated type is class-wide and the root type
3170 -- is the record owning the component. This scenario results
3171 -- in a circularity because the class-wide type requires
3172 -- primitives that have not been created yet as the root
3173 -- type is in the process of being frozen.
3175 -- type Rec is tagged;
3176 -- type Rec_Ptr is access all Rec'Class;
3177 -- type Rec_Array is array ... of Rec_Ptr;
3179 -- type Rec is record
3180 -- Comp : Rec_Array := (others => ...);
3181 -- end record;
3185 then
3193 then
3203 SSO_ADC := Get_Attribute_Definition_Clause
3206 -- Check consistent attribute setting on component types
3208 declare
3210 begin
3213 Check_Component_Storage_Order
3223 -- Deal with default setting of reverse storage order
3227 -- Now deal with reverse storage order/bit order issues
3231 -- Check compatibility of Scalar_Storage_Order with Bit_Order, if
3232 -- the former is specified.
3236 -- Note: report error on Rec, not on SSO_ADC, as ADC may apply
3237 -- to some ancestor type.
3240 Error_Msg_N
3245 -- Warn if there is an Scalar_Storage_Order attribute definition
3246 -- clause but no component clause, no component that itself has
3247 -- such an attribute definition, and no pragma Pack.
3250 or else
3251 SSO_ADC_Component
3252 or else
3254 then
3255 Error_Msg_N
3257 SSO_ADC);
3261 -- Deal with Bit_Order aspect
3269 then
3270 -- Warn if clause has no effect when no component clause is
3271 -- present, but suppress warning if the Bit_Order is required
3272 -- due to the presence of a Scalar_Storage_Order attribute.
3274 Error_Msg_N
3276 Error_Msg_N
3279 -- Here is where we do the processing to adjust component clauses
3280 -- for reversed bit order, when not using reverse SSO.
3284 then
3287 -- Case where we have both an explicit Bit_Order and the same
3288 -- Scalar_Storage_Order: leave record untouched, the back-end
3289 -- will take care of required layout conversions.
3291 else
3297 -- Complete error checking on record representation clause (e.g.
3298 -- overlap of components). This is called after adjusting the
3299 -- record for reverse bit order.
3301 declare
3303 begin
3309 -- Set OK_To_Reorder_Components depending on debug flags
3313 or else
3315 then
3320 -- Check for useless pragma Pack when all components placed. We only
3321 -- do this check for record types, not subtypes, since a subtype may
3322 -- have all its components placed, and it still makes perfectly good
3323 -- sense to pack other subtypes or the parent type. We do not give
3324 -- this warning if Optimize_Alignment is set to Space, since the
3325 -- pragma Pack does have an effect in this case (it always resets
3326 -- the alignment to one).
3330 and then not Unplaced_Component
3332 then
3333 -- Reset packed status. Probably not necessary, but we do it so
3334 -- that there is no chance of the back end doing something strange
3335 -- with this redundant indication of packing.
3339 -- Give warning if redundant constructs warnings on
3342 Error_Msg_N -- CODEFIX
3348 -- If this is the record corresponding to a remote type, freeze the
3349 -- remote type here since that is what we are semantically freezing.
3350 -- This prevents the freeze node for that type in an inner scope.
3357 -- Check for controlled components and unchecked unions.
3362 -- Do not set Has_Controlled_Component on a class-wide
3363 -- equivalent type. See Make_CW_Equivalent_Type.
3366 and then
3368 or else
3371 or else
3373 and then
3375 and then
3376 Has_Controlled_Component
3378 then
3386 -- Scan component declaration for likely misuses of current
3387 -- instance, either in a constraint or a default expression.
3397 -- Enforce the restriction that access attributes with a current
3398 -- instance prefix can only apply to limited types. This comment
3399 -- is floating here, but does not seem to belong here???
3401 -- Set component alignment if not otherwise already set
3405 -- For first subtypes, check if there are any fixed-point fields with
3406 -- component clauses, where we must check the size. This is not done
3407 -- till the freeze point since for fixed-point types, we do not know
3408 -- the size until the type is frozen. Similar processing applies to
3409 -- bit packed arrays.
3417 then
3418 Check_Size
3422 Junk);
3429 -- Generate warning for applying C or C++ convention to a record
3430 -- with discriminants. This is suppressed for the unchecked union
3431 -- case, since the whole point in this case is interface C. We also
3432 -- do not generate this within instantiations, since we will have
3433 -- generated a message on the template.
3438 or else
3441 and then not In_Instance
3444 then
3445 declare
3449 begin
3454 Error_Msg_N
3456 A2);
3457 else
3458 Error_Msg_N
3460 A2);
3463 Error_Msg_NE
3469 -- See if Size is too small as is (and implicit packing might help)
3473 -- No implicit packing if even one component is explicitly placed
3475 and then not Placed_Component
3477 -- Or even one component is aliased
3479 and then not Aliased_Component
3481 -- Must have size clause and all scalar components
3484 and then All_Scalar_Components
3486 -- Do not try implicit packing on records with discriminants, too
3487 -- complicated, especially in the variant record case.
3491 -- We can implicitly pack if the specified size of the record is
3492 -- less than the sum of the object sizes (no point in packing if
3493 -- this is not the case).
3497 -- And the total RM size cannot be greater than the specified size
3498 -- since otherwise packing will not get us where we have to be.
3502 -- Never do implicit packing in CodePeer or SPARK modes since
3503 -- we don't do any packing in these modes, since this generates
3504 -- over-complex code that confuses static analysis, and in
3505 -- general, neither CodePeer not GNATprove care about the
3506 -- internal representation of objects.
3509 then
3510 -- If implicit packing enabled, do it
3515 -- Otherwise flag the size clause
3517 else
3518 declare
3520 begin
3521 Error_Msg_NE -- CODEFIX
3523 Error_Msg_N -- CODEFIX
3530 -- The following checks are only relevant when SPARK_Mode is on as
3531 -- they are not standard Ada legality rules.
3536 -- A discriminated type cannot be effectively volatile
3537 -- (SPARK RM C.6(4)).
3542 -- A tagged type cannot be effectively volatile
3543 -- (SPARK RM C.6(5)).
3549 -- A non-effectively volatile record type cannot contain
3550 -- effectively volatile components (SPARK RM C.6(2)).
3552 else
3557 then
3559 Error_Msg_N
3569 -- All done if not a full record definition
3575 -- Finally we need to check the variant part to make sure that
3576 -- all types within choices are properly frozen as part of the
3577 -- freezing of the record type.
3584 begin
3585 -- Find component list
3597 then
3602 -- Case of variant part present
3608 -- Note: we used to call Check_Choices here, but it is too early,
3609 -- since predicated subtypes are frozen here, but their freezing
3610 -- actions are in Analyze_Freeze_Entity, which has not been called
3611 -- yet for entities frozen within this procedure, so we moved that
3612 -- call to the Analyze_Freeze_Entity for the record type.
3617 -------------------------------
3618 -- Has_Boolean_Aspect_Import --
3619 -------------------------------
3626 begin
3632 -- The value of aspect Import is True when the expression is
3633 -- either missing or it is explicitly set to True.
3639 then
3650 ----------------------------
3651 -- Late_Freeze_Subprogram --
3652 ----------------------------
3659 begin
3662 else
3669 ------------------------------
3670 -- Wrap_Imported_Subprogram --
3671 ------------------------------
3673 -- The issue here is that our normal approach of checking preconditions
3674 -- and postconditions does not work for imported procedures, since we
3675 -- are not generating code for the body. To get around this we create
3676 -- a wrapper, as shown by the following example:
3678 -- procedure K (A : Integer);
3679 -- pragma Import (C, K);
3681 -- The spec is rewritten by removing the effects of pragma Import, but
3682 -- leaving the convention unchanged, as though the source had said:
3684 -- procedure K (A : Integer);
3685 -- pragma Convention (C, K);
3687 -- and we create a body, added to the entity K freeze actions, which
3688 -- looks like:
3690 -- procedure K (A : Integer) is
3691 -- procedure K (A : Integer);
3692 -- pragma Import (C, K);
3693 -- begin
3694 -- K (A);
3695 -- end K;
3697 -- Now the contract applies in the normal way to the outer procedure,
3698 -- and the inner procedure has no contracts, so there is no problem
3699 -- in just calling it to get the original effect.
3701 -- In the case of a function, we create an appropriate return statement
3702 -- for the subprogram body that calls the inner procedure.
3714 begin
3715 -- Nothing to do if not imported
3720 -- Test enabling conditions for wrapping
3725 and then not GNATprove_Mode
3726 then
3727 -- Here we do the wrap
3729 -- Note on calls to Copy_Separate_Tree. The trees we are copying
3730 -- here are fully analyzed, but we definitely want fully syntactic
3731 -- unanalyzed trees in the body we construct, so that the analysis
3732 -- generates the right visibility, and that is exactly what the
3733 -- calls to Copy_Separate_Tree give us.
3735 -- Acquire copy of Inline pragma
3739 -- Fix up spec to be not imported any more
3746 -- Grab the subprogram declaration and specification
3750 -- Build parameter list that we need
3759 -- Build the call
3762 Stmt :=
3764 Expression =>
3769 else
3770 Stmt :=
3776 -- Now build the body
3778 Bod :=
3780 Specification =>
3784 Specification =>
3786 Iprag),
3787 Handled_Statement_Sequence =>
3792 -- Append the body to freeze result
3797 -- Case of imported subprogram that does not get wrapped
3799 else
3800 -- Set Is_Public. All imported entities need an external symbol
3801 -- created for them since they are always referenced from another
3802 -- object file. Note this used to be set when we set Is_Imported
3803 -- back in Sem_Prag, but now we delay it to this point, since we
3804 -- don't want to set this flag if we wrap an imported subprogram.
3810 -- Start of processing for Freeze_Entity
3812 begin
3813 -- We are going to test for various reasons why this entity need not be
3814 -- frozen here, but in the case of an Itype that's defined within a
3815 -- record, that test actually applies to the record.
3821 then
3825 -- Do not freeze if already frozen since we only need one freeze node
3830 -- It is improper to freeze an external entity within a generic because
3831 -- its freeze node will appear in a non-valid context. The entity will
3832 -- be frozen in the proper scope after the current generic is analyzed.
3833 -- However, aspects must be analyzed because they may be queried later
3834 -- within the generic itself, and the corresponding pragma or attribute
3835 -- definition has not been analyzed yet.
3844 -- AI05-0213: A formal incomplete type does not freeze the actual. In
3845 -- the instance, the same applies to the subtype renaming the actual.
3851 then
3854 -- Formal subprograms are never frozen
3859 -- Generic types are never frozen as they lack delayed semantic checks
3864 -- Do not freeze a global entity within an inner scope created during
3865 -- expansion. A call to subprogram E within some internal procedure
3866 -- (a stream attribute for example) might require freezing E, but the
3867 -- freeze node must appear in the same declarative part as E itself.
3868 -- The two-pass elaboration mechanism in gigi guarantees that E will
3869 -- be frozen before the inner call is elaborated. We exclude constants
3870 -- from this test, because deferred constants may be frozen early, and
3871 -- must be diagnosed (e.g. in the case of a deferred constant being used
3872 -- in a default expression). If the enclosing subprogram comes from
3873 -- source, or is a generic instance, then the freeze point is the one
3874 -- mandated by the language, and we freeze the entity. A subprogram that
3875 -- is a child unit body that acts as a spec does not have a spec that
3876 -- comes from source, but can only come from source.
3881 then
3882 declare
3885 begin
3892 then
3894 else
3903 -- Similarly, an inlined instance body may make reference to global
3904 -- entities, but these references cannot be the proper freezing point
3905 -- for them, and in the absence of inlining freezing will take place in
3906 -- their own scope. Normally instance bodies are analyzed after the
3907 -- enclosing compilation, and everything has been frozen at the proper
3908 -- place, but with front-end inlining an instance body is compiled
3909 -- before the end of the enclosing scope, and as a result out-of-order
3910 -- freezing must be prevented.
3912 elsif Front_End_Inlining
3913 and then In_Instance_Body
3915 then
3916 declare
3919 begin
3924 else
3938 -- Add checks to detect proper initialization of scalars that may appear
3939 -- as subprogram parameters.
3945 -- Deal with delayed aspect specifications. The analysis of the aspect
3946 -- is required to be delayed to the freeze point, thus we analyze the
3947 -- pragma or attribute definition clause in the tree at this point. We
3948 -- also analyze the aspect specification node at the freeze point when
3949 -- the aspect doesn't correspond to pragma/attribute definition clause.
3955 -- Here to freeze the entity
3959 -- Case of entity being frozen is other than a type
3963 -- If entity is exported or imported and does not have an external
3964 -- name, now is the time to provide the appropriate default name.
3965 -- Skip this if the entity is stubbed, since we don't need a name
3966 -- for any stubbed routine. For the case on intrinsics, if no
3967 -- external name is specified, then calls will be handled in
3968 -- Exp_Intr.Expand_Intrinsic_Call, and no name is needed. If an
3969 -- external name is provided, then Expand_Intrinsic_Call leaves
3970 -- calls in place for expansion by GIGI.
3976 then
3977 Set_Encoded_Interface_Name
3980 -- If entity is an atomic object appearing in a declaration and
3981 -- the expression is an aggregate, assign it to a temporary to
3982 -- ensure that the actual assignment is done atomically rather
3983 -- than component-wise (the assignment to the temp may be done
3984 -- component-wise, but that is harmless).
3991 then
3995 -- Subprogram case
3999 -- Check for needing to wrap imported subprogram
4003 -- Freeze all parameter types and the return type (RM 13.14(14)).
4004 -- However skip this for internal subprograms. This is also where
4005 -- any extra formal parameters are created since we now know
4006 -- whether the subprogram will use a foreign convention.
4009 declare
4014 begin
4015 -- Loop through formals
4021 -- AI05-0151: incomplete types can appear in a profile.
4022 -- By the time the entity is frozen, the full view must
4023 -- be available, unless it is a limited view.
4028 then
4040 then
4041 -- If the type of a formal is incomplete, subprogram
4042 -- is being frozen prematurely. Within an instance
4043 -- (but not within a wrapper package) this is an
4044 -- artifact of our need to regard the end of an
4045 -- instantiation as a freeze point. Otherwise it is
4046 -- a definite error.
4052 elsif not After_Last_Declaration
4053 and then not Freezing_Library_Level_Tagged_Type
4054 then
4056 Error_Msg
4058 Loc);
4062 -- Check suspicious parameter for C function. These tests
4063 -- apply only to exported/imported subprograms.
4065 if Warn_On_Export_Import
4068 or else
4075 then
4076 -- Qualify mention of formals with subprogram name
4080 -- Check suspicious use of fat C pointer
4084 then
4085 Error_Msg_N
4087 Formal);
4089 -- Check suspicious return of boolean
4096 then
4097 Error_Msg_N
4099 Error_Msg_N
4103 -- Check suspicious tagged type
4107 and then
4108 Is_Tagged_Type
4111 then
4112 Error_Msg_N
4116 -- Check wrong convention subprogram pointer
4120 then
4121 Error_Msg_N
4125 Error_Msg_NE
4130 -- Turn off name qualification after message output
4135 -- Check for unconstrained array in exported foreign
4136 -- convention case.
4142 and then Warn_On_Export_Import
4144 -- Exclude VM case, since both .NET and JVM can handle
4145 -- unconstrained arrays without a problem.
4148 then
4151 -- If this is an inherited operation, place the
4152 -- warning on the derived type declaration, rather
4153 -- than on the original subprogram.
4156 N_Full_Type_Declaration
4157 then
4161 Error_Msg_NE
4164 else
4168 Error_Msg_NE
4171 Error_Msg_NE
4182 -- If the formal is an anonymous_access_to_subprogram
4183 -- freeze the subprogram type as well, to prevent
4184 -- scope anomalies in gigi, because there is no other
4185 -- clear point at which it could be frozen.
4189 then
4197 -- Case of function: similar checks on return type
4201 -- Check whether function is declared elsewhere.
4203 Late_Freezing :=
4208 -- Freeze return type
4212 -- AI05-0151: the return type may have been incomplete
4213 -- at the point of declaration. Replace it with the full
4214 -- view, unless the current type is a limited view. In
4215 -- that case the full view is in a different unit, and
4216 -- gigi finds the non-limited view after the other unit
4217 -- is elaborated.
4222 then
4226 -- If the return type is a limited view and the non-
4227 -- limited view is still incomplete, the function has
4228 -- to be frozen at a later time.
4232 and then
4234 then
4242 -- Check suspicious return type for C function
4244 if Warn_On_Export_Import
4246 or else
4249 then
4250 -- Check suspicious return of fat C pointer
4256 then
4257 Error_Msg_N
4261 -- Check suspicious return of boolean
4269 then
4270 declare
4273 begin
4274 Error_Msg_NE
4277 Error_Msg_NE
4282 -- Check suspicious return tagged type
4286 and then
4287 Is_Tagged_Type
4292 then
4293 Error_Msg_N
4297 -- Check return of wrong convention subprogram pointer
4303 then
4304 Error_Msg_N
4308 Error_Msg_NE
4314 -- Give warning for suspicious return of a result of an
4315 -- unconstrained array type in a foreign convention
4316 -- function.
4320 -- We are looking for a return of unconstrained array
4325 -- Exclude imported routines, the warning does not
4326 -- belong on the import, but rather on the routine
4327 -- definition.
4331 -- Exclude VM case, since both .NET and JVM can handle
4332 -- return of unconstrained arrays without a problem.
4336 -- Check that general warning is enabled, and that it
4337 -- is not suppressed for this particular case.
4339 and then Warn_On_Export_Import
4342 then
4343 Error_Msg_N
4351 -- Must freeze its parent first if it is a derived subprogram
4357 -- We don't freeze internal subprograms, because we don't normally
4358 -- want addition of extra formals or mechanism setting to happen
4359 -- for those. However we do pass through predefined dispatching
4360 -- cases, since extra formals may be needed in some cases, such as
4361 -- for the stream 'Input function (build-in-place formals).
4365 then
4374 -- If warning on suspicious contracts then check for the case of
4375 -- a postcondition other than False for a No_Return subprogram.
4378 and then Warn_On_Suspicious_Contract
4380 then
4381 declare
4385 begin
4388 Name_Postcondition,
4389 Name_Refined_Post)
4390 then
4391 Exp :=
4392 Expression
4397 then
4398 Error_Msg_NE
4409 -- Here for other than a subprogram or type
4411 else
4412 -- If entity has a type, and it is not a generic unit, then
4413 -- freeze it first (RM 13.14(10)).
4417 then
4421 -- Special processing for objects created by object declaration
4425 -- Abstract type allowed only for C++ imported variables or
4426 -- constants.
4428 -- Note: we inhibit this check for objects that do not come
4429 -- from source because there is at least one case (the
4430 -- expansion of x'Class'Input where x is abstract) where we
4431 -- legitimately generate an abstract object.
4437 then
4442 Error_Msg_NE
4448 -- For object created by object declaration, perform required
4449 -- categorization (preelaborate and pure) checks. Defer these
4450 -- checks to freeze time since pragma Import inhibits default
4451 -- initialization and thus pragma Import affects these checks.
4455 -- If there is an address clause, check that it is valid
4459 -- Reset Is_True_Constant for aliased object. We consider that
4460 -- the fact that something is aliased may indicate that some
4461 -- funny business is going on, e.g. an aliased object is passed
4462 -- by reference to a procedure which captures the address of
4463 -- the object, which is later used to assign a new value. Such
4464 -- code is highly dubious, but we choose to make it "work" for
4465 -- aliased objects.
4467 -- However, we don't do that for internal entities. We figure
4468 -- that if we deliberately set Is_True_Constant for an internal
4469 -- entity, e.g. a dispatch table entry, then we mean it.
4473 then
4477 -- If the object needs any kind of default initialization, an
4478 -- error must be issued if No_Default_Initialization applies.
4479 -- The check doesn't apply to imported objects, which are not
4480 -- ever default initialized, and is why the check is deferred
4481 -- until freezing, at which point we know if Import applies.
4482 -- Deferred constants are also exempted from this test because
4483 -- their completion is explicit, or through an import pragma.
4487 then
4493 and then
4498 or else
4501 then
4503 Check_Restriction
4507 -- Check that a Thread_Local_Storage variable does not have
4508 -- default initialization, and any explicit initialization must
4509 -- either be the null constant or a static constant.
4512 declare
4514 begin
4515 if Has_Default_Initialization
4516 or else
4518 and then
4520 or else not
4522 or else
4524 then
4525 Error_Msg_NE
4528 Error_Msg_NE
4535 -- For imported objects, set Is_Public unless there is also an
4536 -- address clause, which means that there is no external symbol
4537 -- needed for the Import (Is_Public may still be set for other
4538 -- unrelated reasons). Note that we delayed this processing
4539 -- till freeze time so that we can be sure not to set the flag
4540 -- if there is an address clause. If there is such a clause,
4541 -- then the only purpose of the Import pragma is to suppress
4542 -- implicit initialization.
4548 -- For source objects that are not Imported and are library
4549 -- level, if no linker section pragma was given inherit the
4550 -- appropriate linker section from the corresponding type.
4556 then
4557 Set_Linker_Section_Pragma
4561 -- For convention C objects of an enumeration type, warn if
4562 -- the size is not integer size and no explicit size given.
4563 -- Skip warning for Boolean, and Character, assume programmer
4564 -- expects 8-bit sizes for these cases.
4567 or else
4574 then
4576 Error_Msg_N
4578 E);
4583 -- Check that a constant which has a pragma Volatile[_Components]
4584 -- or Atomic[_Components] also has a pragma Import (RM C.6(13)).
4586 -- Note: Atomic[_Components] also sets Volatile[_Components]
4592 then
4593 -- Make sure we actually have a pragma, and have not merely
4594 -- inherited the indication from elsewhere (e.g. an address
4595 -- clause, which is not good enough in RM terms).
4598 or else
4600 then
4601 Error_Msg_N
4606 or else
4608 then
4609 Error_Msg_N
4615 -- Static objects require special handling
4619 then
4623 -- Remaining step is to layout objects
4627 then
4631 -- For an object that does not have delayed freezing, and whose
4632 -- initialization actions have been captured in a compound
4633 -- statement, move them back now directly within the enclosing
4634 -- statement sequence.
4638 then
4643 -- Case of a type or subtype being frozen
4645 else
4646 -- We used to check here that a full type must have preelaborable
4647 -- initialization if it completes a private type specified with
4648 -- pragma Preelaborable_Initialization, but that missed cases where
4649 -- the types occur within a generic package, since the freezing
4650 -- that occurs within a containing scope generally skips traversal
4651 -- of a generic unit's declarations (those will be frozen within
4652 -- instances). This check was moved to Analyze_Package_Specification.
4654 -- The type may be defined in a generic unit. This can occur when
4655 -- freezing a generic function that returns the type (which is
4656 -- defined in a parent unit). It is clearly meaningless to freeze
4657 -- this type. However, if it is a subtype, its size may be determi-
4658 -- nable and used in subsequent checks, so might as well try to
4659 -- compute it.
4661 -- In Ada 2012, Freeze_Entities is also used in the front end to
4662 -- trigger the analysis of aspect expressions, so in this case we
4663 -- want to continue the freezing process.
4667 and then
4670 then
4675 -- Check for error of Type_Invariant'Class applied to an untagged
4676 -- type (check delayed to freeze time when full type is available).
4678 declare
4680 begin
4684 then
4685 Error_Msg_NE
4688 Error_Msg_N
4693 -- Deal with special cases of freezing for subtype
4697 -- Before we do anything else, a specialized test for the case of
4698 -- a size given for an array where the array needs to be packed,
4699 -- but was not so the size cannot be honored. This is the case
4700 -- where implicit packing may apply. The reason we do this so
4701 -- early is that if we have implicit packing, the layout of the
4702 -- base type is affected, so we must do this before we freeze
4703 -- the base type.
4705 -- We could do this processing only if implicit packing is enabled
4706 -- since in all other cases, the error would be caught by the back
4707 -- end. However, we choose to do the check even if we do not have
4708 -- implicit packing enabled, since this allows us to give a more
4709 -- useful error message (advising use of pragmas Implicit_Packing
4710 -- or Pack).
4713 declare
4724 -- Number of elements in array
4726 begin
4727 -- Check enabling conditions. These are straightforward
4728 -- except for the test for a limited composite type. This
4729 -- eliminates the rare case of a array of limited components
4730 -- where there are issues of whether or not we can go ahead
4731 -- and pack the array (since we can't freely pack and unpack
4732 -- arrays if they are limited).
4734 -- Note that we check the root type explicitly because the
4735 -- whole point is we are doing this test before we have had
4736 -- a chance to freeze the base type (and it is that freeze
4737 -- action that causes stuff to be inherited).
4750 then
4751 -- Compute number of elements in array
4759 and then
4761 then
4765 Num_Elmts :=
4766 Num_Elmts *
4772 -- What we are looking for here is the situation where
4773 -- the RM_Size given would be exactly right if there was
4774 -- a pragma Pack (resulting in the component size being
4775 -- the same as the RM_Size). Furthermore, the component
4776 -- type size must be an odd size (not a multiple of
4777 -- storage unit). If the component RM size is an exact
4778 -- number of storage units that is a power of two, the
4779 -- array is not packed and has a standard representation.
4783 then
4784 -- For implicit packing mode, just set the component
4785 -- size silently.
4793 -- Otherwise give an error message
4795 else
4796 Error_Msg_NE
4798 Error_Msg_N -- CODEFIX
4804 and then Implicit_Packing
4805 and then
4807 or else
4809 or else
4811 then
4812 -- Not a packed array, but indicate the desired
4813 -- component size, for the back-end.
4823 -- If ancestor subtype present, freeze that first. Note that this
4824 -- will also get the base type frozen. Need RM reference ???
4831 -- No ancestor subtype present
4833 else
4834 -- See if we have a nearest ancestor that has a predicate.
4835 -- That catches the case of derived type with a predicate.
4836 -- Need RM reference here ???
4844 -- Freeze base type before freezing the entity (RM 13.14(15))
4851 -- A subtype inherits all the type-related representation aspects
4852 -- from its parents (RM 13.1(8)).
4856 -- For a derived type, freeze its parent type first (RM 13.14(15))
4862 -- A derived type inherits each type-related representation aspect
4863 -- of its parent type that was directly specified before the
4864 -- declaration of the derived type (RM 13.1(15)).
4869 -- Check for incompatible size and alignment for record type
4871 if Warn_On_Size_Alignment
4875 -- If explicit Object_Size clause given assume that the programmer
4876 -- knows what he is doing, and expects the compiler behavior.
4880 -- Check for size not a multiple of alignment
4883 then
4884 declare
4890 begin
4893 -- Give a warning
4897 Error_Msg_NE
4903 else
4905 Error_Msg_NE
4918 -- Array type
4923 -- For a class-wide type, the corresponding specific type is
4924 -- frozen as well (RM 13.14(15))
4929 -- If the base type of the class-wide type is still incomplete,
4930 -- the class-wide remains unfrozen as well. This is legal when
4931 -- E is the formal of a primitive operation of some other type
4932 -- which is being frozen.
4939 -- The equivalent type associated with a class-wide subtype needs
4940 -- to be frozen to ensure that its layout is done.
4944 then
4948 -- Generate an itype reference for a library-level class-wide type
4949 -- at the freeze point. Otherwise the first explicit reference to
4950 -- the type may appear in an inner scope which will be rejected by
4951 -- the back-end.
4955 then
4956 declare
4959 begin
4962 -- From a gigi point of view, a class-wide subtype derives
4963 -- from its record equivalent type. As a result, the itype
4964 -- reference must appear after the freeze node of the
4965 -- equivalent type or gigi will reject the reference.
4969 then
4971 else
4977 -- For a record type or record subtype, freeze all component types
4978 -- (RM 13.14(15)). We test for E_Record_(sub)Type here, rather than
4979 -- using Is_Record_Type, because we don't want to attempt the freeze
4980 -- for the case of a private type with record extension (we will do
4981 -- that later when the full type is frozen).
4985 then
4988 -- For a concurrent type, freeze corresponding record type. This does
4989 -- not correspond to any specific rule in the RM, but the record type
4990 -- is essentially part of the concurrent type. Also freeze all local
4991 -- entities. This includes record types created for entry parameter
4992 -- blocks and whatever local entities may appear in the private part.
5006 -- The guard on the presence of the Etype seems to be needed
5007 -- for some CodePeer (-gnatcC) cases, but not clear why???
5012 then
5023 -- Private types are required to point to the same freeze node as
5024 -- their corresponding full views. The freeze node itself has to
5025 -- point to the partial view of the entity (because from the partial
5026 -- view, we can retrieve the full view, but not the reverse).
5027 -- However, in order to freeze correctly, we need to freeze the full
5028 -- view. If we are freezing at the end of a scope (or within the
5029 -- scope) of the private type, the partial and full views will have
5030 -- been swapped, the full view appears first in the entity chain and
5031 -- the swapping mechanism ensures that the pointers are properly set
5032 -- (on scope exit).
5034 -- If we encounter the partial view before the full view (e.g. when
5035 -- freezing from another scope), we freeze the full view, and then
5036 -- set the pointers appropriately since we cannot rely on swapping to
5037 -- fix things up (subtypes in an outer scope might not get swapped).
5039 -- If the full view is itself private, the above requirements apply
5040 -- to the underlying full view instead of the full view. But there is
5041 -- no swapping mechanism for the underlying full view so we need to
5042 -- set the pointers appropriately in both cases.
5046 then
5047 -- The construction of the dispatch table associated with library
5048 -- level tagged types forces freezing of all the primitives of the
5049 -- type, which may cause premature freezing of the partial view.
5050 -- For example:
5052 -- package Pkg is
5053 -- type T is tagged private;
5054 -- type DT is new T with private;
5055 -- procedure Prim (X : in out T; Y : in out DT'Class);
5056 -- private
5057 -- type T is tagged null record;
5058 -- Obj : T;
5059 -- type DT is new T with null record;
5060 -- end;
5062 -- In this case the type will be frozen later by the usual
5063 -- mechanism: an object declaration, an instantiation, or the
5064 -- end of a declarative part.
5068 then
5072 -- Case of full view present
5076 -- If full view has already been frozen, then no further
5077 -- processing is required
5083 -- Otherwise freeze full view and patch the pointers so that
5084 -- the freeze node will elaborate both views in the back end.
5085 -- However, if full view is itself private, freeze underlying
5086 -- full view instead and patch the pointers so that the freeze
5087 -- node will elaborate the three views in the back end.
5089 else
5090 declare
5093 begin
5096 then
5104 then
5111 else
5124 else
5125 -- {Incomplete,Private}_Subtypes with Full_Views
5126 -- constrained by discriminants.
5137 -- AI-117 requires that the convention of a partial view be the
5138 -- same as the convention of the full view. Note that this is a
5139 -- recognized breach of privacy, but it's essential for logical
5140 -- consistency of representation, and the lack of a rule in
5141 -- RM95 was an oversight.
5148 -- Size information is copied from the full view to the
5149 -- incomplete or private view for consistency.
5151 -- We skip this is the full view is not a type. This is very
5152 -- strange of course, and can only happen as a result of
5153 -- certain illegalities, such as a premature attempt to derive
5154 -- from an incomplete type.
5163 -- Case of underlying full view present
5167 then
5172 -- Patch the pointers so that the freeze node will elaborate
5173 -- both views in the back end.
5182 else
5192 -- Case of no full view present. If entity is derived or subtype,
5193 -- it is safe to freeze, correctness depends on the frozen status
5194 -- of parent. Otherwise it is either premature usage, or a Taft
5195 -- amendment type, so diagnosis is at the point of use and the
5196 -- type might be frozen later.
5201 else
5206 -- For access subprogram, freeze types of all formals, the return
5207 -- type was already frozen, since it is the Etype of the function.
5208 -- Formal types can be tagged Taft amendment types, but otherwise
5209 -- they cannot be incomplete.
5217 then
5221 -- AI05-151: Incomplete types are allowed in access to
5222 -- subprogram specifications.
5225 Error_Msg_NE
5236 -- For access to a protected subprogram, freeze the equivalent type
5237 -- (however this is not set if we are not generating code or if this
5238 -- is an anonymous type used just for resolution).
5246 -- Generic types are never seen by the back-end, and are also not
5247 -- processed by the expander (since the expander is turned off for
5248 -- generic processing), so we never need freeze nodes for them.
5254 -- Some special processing for non-generic types to complete
5255 -- representation details not known till the freeze point.
5260 -- Some error checks required for ordinary fixed-point type. Defer
5261 -- these till the freeze-point since we need the small and range
5262 -- values. We only do these checks for base types
5267 Error_Msg_N
5272 Error_Msg_N
5278 Error_Msg_N
5284 Error_Msg_N
5296 and then Warn_On_Suspicious_Modulus_Value
5297 then
5303 then
5304 -- If a pragma Default_Storage_Pool applies, and this type has no
5305 -- Storage_Pool or Storage_Size clause (which must have occurred
5306 -- before the freezing point), then use the default. This applies
5307 -- only to base types.
5309 -- None of this applies to access to subprograms, for which there
5310 -- are clearly no pools.
5316 then
5317 -- Case of pragma Default_Storage_Pool (null)
5322 -- Case of pragma Default_Storage_Pool (storage_pool_NAME)
5324 else
5329 -- Check restriction for standard storage pool
5335 -- Deal with error message for pure access type. This is not an
5336 -- error in Ada 2005 if there is no pool (see AI-366).
5342 then
5346 Error_Msg_N
5350 Error_Msg_N
5353 else
5354 Error_Msg_N
5361 -- Case of composite types
5365 -- AI-117 requires that all new primitives of a tagged type must
5366 -- inherit the convention of the full view of the type. Inherited
5367 -- and overriding operations are defined to inherit the convention
5368 -- of their parent or overridden subprogram (also specified in
5369 -- AI-117), which will have occurred earlier (in Derive_Subprogram
5370 -- and New_Overloaded_Entity). Here we set the convention of
5371 -- primitives that are still convention Ada, which will ensure
5372 -- that any new primitives inherit the type's convention. Class-
5373 -- wide types can have a foreign convention inherited from their
5374 -- specific type, but are excluded from this since they don't have
5375 -- any associated primitives.
5380 then
5381 declare
5385 begin
5397 -- If the type is a simple storage pool type, then this is where
5398 -- we attempt to locate and validate its Allocate, Deallocate, and
5399 -- Storage_Size operations (the first is required, and the latter
5400 -- two are optional). We also verify that the full type for a
5401 -- private type is allowed to be a simple storage pool type.
5405 then
5406 -- If the type is marked Has_Private_Declaration, then this is
5407 -- a full type for a private type that was specified with the
5408 -- pragma Simple_Storage_Pool_Type, and here we ensure that the
5409 -- pragma is allowed for the full type (for example, it can't
5410 -- be an array type, or a nonlimited record type).
5415 then
5417 Error_Msg_N
5428 procedure Validate_Simple_Pool_Op_Formal
5435 -- Validate one formal Pool_Op_Formal of the candidate pool
5436 -- operation Pool_Op. The formal must be of Expected_Type
5437 -- and have mode Expected_Mode. OK_Formal will be set to
5438 -- False if the formal doesn't match. If OK_Formal is False
5439 -- on entry, then the formal will effectively be ignored
5440 -- (because validation of the pool op has already failed).
5441 -- Upon return, Pool_Op_Formal will be updated to the next
5442 -- formal, if any.
5444 procedure Validate_Simple_Pool_Operation
5446 -- Search for and validate a simple pool operation with the
5447 -- name Op_Name. If the name is Allocate, then there must be
5448 -- exactly one such primitive operation for the simple pool
5449 -- type. If the name is Deallocate or Storage_Size, then
5450 -- there can be at most one such primitive operation. The
5451 -- profile of the located primitive must conform to what
5452 -- is expected for each operation.
5454 ------------------------------------
5455 -- Validate_Simple_Pool_Op_Formal --
5456 ------------------------------------
5458 procedure Validate_Simple_Pool_Op_Formal
5465 is
5466 begin
5467 -- If OK_Formal is False on entry, then simply ignore
5468 -- the formal, because an earlier formal has already
5469 -- been flagged.
5474 -- If no formal is passed in, then issue an error for a
5475 -- missing formal.
5478 Error_Msg_NE
5488 -- If the pool type was expected for this formal, then
5489 -- this will not be considered a candidate operation
5490 -- for the simple pool, so we unset OK_Formal so that
5491 -- the op and any later formals will be ignored.
5498 else
5499 Error_Msg_NE
5506 -- Issue error if formal's mode is not the expected one
5509 Error_Msg_N
5511 Pool_Op_Formal);
5514 -- Advance to the next formal
5519 ------------------------------------
5520 -- Validate_Simple_Pool_Operation --
5521 ------------------------------------
5523 procedure Validate_Simple_Pool_Operation
5525 is
5531 begin
5532 pragma Assert
5534 Name_Deallocate,
5535 Name_Storage_Size));
5539 -- For each homonym declared immediately in the scope
5540 -- of the simple storage pool type, determine whether
5541 -- the homonym is an operation of the pool type, and,
5542 -- if so, check that its profile is as expected for
5543 -- a simple pool operation of that name.
5549 then
5554 -- The first parameter must be of the pool type
5555 -- in order for the operation to qualify.
5558 Validate_Simple_Pool_Op_Formal
5561 else
5562 Validate_Simple_Pool_Op_Formal
5567 -- If another operation with this name has already
5568 -- been located for the type, then flag an error,
5569 -- since we only allow the type to have a single
5570 -- such primitive.
5573 Error_Msg_NE
5578 -- In the case of Allocate and Deallocate, a formal
5579 -- of type System.Address is required.
5582 Validate_Simple_Pool_Op_Formal
5587 Validate_Simple_Pool_Op_Formal
5592 -- In the case of Allocate and Deallocate, formals
5593 -- of type Storage_Count are required as the third
5594 -- and fourth parameters.
5597 Validate_Simple_Pool_Op_Formal
5600 Validate_Simple_Pool_Op_Formal
5605 -- If no mismatched formals have been found (Is_OK)
5606 -- and no excess formals are present, then this
5607 -- operation has been validated, so record it.
5617 -- There must be a valid Allocate operation for the type,
5618 -- so issue an error if none was found.
5622 then
5628 -- Simple pool operations can't be abstract
5631 Error_Msg_N
5636 -- The Storage_Size operation must be a function with
5637 -- Storage_Count as its result type.
5641 Error_Msg_N
5645 Error_Msg_NE
5650 -- Allocate and Deallocate must be procedures
5653 Error_Msg_N
5659 -- Start of processing for Validate_Simple_Pool_Ops
5661 begin
5669 -- Now that all types from which E may depend are frozen, see if the
5670 -- size is known at compile time, if it must be unsigned, or if
5671 -- strict alignment is required
5680 -- Do not allow a size clause for a type which does not have a size
5681 -- that is known at compile time
5685 then
5686 -- Suppress this message if errors posted on E, even if we are
5687 -- in all errors mode, since this is often a junk message
5690 Error_Msg_N
5696 -- Now we set/verify the representation information, in particular
5697 -- the size and alignment values. This processing is not required for
5698 -- generic types, since generic types do not play any part in code
5699 -- generation, and so the size and alignment values for such types
5700 -- are irrelevant. Ditto for types declared within a generic unit,
5701 -- which may have components that depend on generic parameters, and
5702 -- that will be recreated in an instance.
5707 -- Otherwise we call the layout procedure
5709 else
5713 -- If this is an access to subprogram whose designated type is itself
5714 -- a subprogram type, the return type of this anonymous subprogram
5715 -- type must be decorated as well.
5719 then
5723 -- If the type has a Defaut_Value/Default_Component_Value aspect,
5724 -- this is where we analye the expression (after the type is frozen,
5725 -- since in the case of Default_Value, we are analyzing with the
5726 -- type itself, and we treat Default_Component_Value similarly for
5727 -- the sake of uniformity).
5730 declare
5735 begin
5740 else
5751 Flag_Non_Static_Expr
5758 -- End of freeze processing for type entities
5761 -- Here is where we logically freeze the current entity. If it has a
5762 -- freeze node, then this is the point at which the freeze node is
5763 -- linked into the result list.
5767 -- If a freeze node is already allocated, use it, otherwise allocate
5768 -- a new one. The preallocation happens in the case of anonymous base
5769 -- types, where we preallocate so that we can set First_Subtype_Link.
5770 -- Note that we reset the Sloc to the current freeze location.
5776 else
5787 -- A final pass over record types with discriminants. If the type
5788 -- has an incomplete declaration, there may be constrained access
5789 -- subtypes declared elsewhere, which do not depend on the discrimi-
5790 -- nants of the type, and which are used as component types (i.e.
5791 -- the full view is a recursive type). The designated types of these
5792 -- subtypes can only be elaborated after the type itself, and they
5793 -- need an itype reference.
5797 then
5798 declare
5803 begin
5813 then
5825 -- When a type is frozen, the first subtype of the type is frozen as
5826 -- well (RM 13.14(15)). This has to be done after freezing the type,
5827 -- since obviously the first subtype depends on its own base type.
5832 -- If we just froze a tagged non-class wide record, then freeze the
5833 -- corresponding class-wide type. This must be done after the tagged
5834 -- type itself is frozen, because the class-wide type refers to the
5835 -- tagged type which generates the class.
5840 then
5847 -- Special handling for subprograms
5851 -- If subprogram has address clause then reset Is_Public flag, since
5852 -- we do not want the backend to generate external references.
5856 then
5864 -----------------------------
5865 -- Freeze_Enumeration_Type --
5866 -----------------------------
5869 begin
5870 -- By default, if no size clause is present, an enumeration type with
5871 -- Convention C is assumed to interface to a C enum, and has integer
5872 -- size. This applies to types. For subtypes, verify that its base
5873 -- type has no size clause either. Treat other foreign conventions
5874 -- in the same way, and also make sure alignment is set right.
5881 -- Don't do this if Short_Enums on target
5883 and then not Target_Short_Enums
5884 then
5888 -- Normal Ada case or size clause present or not Long_C_Enums on target
5890 else
5891 -- If the enumeration type interfaces to C, and it has a size clause
5892 -- that specifies less than int size, it warrants a warning. The
5893 -- user may intend the C type to be an enum or a char, so this is
5894 -- not by itself an error that the Ada compiler can detect, but it
5895 -- it is a worth a heads-up. For Boolean and Character types we
5896 -- assume that the programmer has the proper C type in mind.
5904 -- Don't do this if Short_Enums on target
5906 and then not Target_Short_Enums
5907 then
5908 Error_Msg_N
5916 -----------------------
5917 -- Freeze_Expression --
5918 -----------------------
5929 -- This flag is set true if the entity must be frozen outside the
5930 -- current subprogram. This happens in the case of expander generated
5931 -- subprograms (_Init_Proc, _Input, _Output, _Read, _Write) which do
5932 -- not freeze all entities like other bodies, but which nevertheless
5933 -- may reference entities that have to be frozen before the body and
5934 -- obviously cannot be frozen inside the body.
5937 -- Given an N_Handled_Sequence_Of_Statements node N, determines whether
5938 -- it is the handled statement sequence of an expander-generated
5939 -- subprogram (init proc, stream subprogram, or renaming as body).
5940 -- If so, this is not a freezing context.
5942 -----------------
5943 -- In_Exp_Body --
5944 -----------------
5950 begin
5953 else
5960 else
5963 -- Following complex conditional could use comments ???
5972 N_Subprogram_Renaming_Declaration,
5973 N_Expression_Function))
5974 then
5976 else
5982 -- Start of processing for Freeze_Expression
5984 begin
5985 -- Immediate return if freezing is inhibited. This flag is set by the
5986 -- analyzer to stop freezing on generated expressions that would cause
5987 -- freezing if they were in the source program, but which are not
5988 -- supposed to freeze, since they are created.
5994 -- If expression is non-static, then it does not freeze in a default
5995 -- expression, see section "Handling of Default Expressions" in the
5996 -- spec of package Sem for further details. Note that we have to make
5997 -- sure that we actually have a real expression (if we have a subtype
5998 -- indication, we can't test Is_OK_Static_Expression). However, we
5999 -- exclude the case of the prefix of an attribute of a static scalar
6000 -- subtype from this early return, because static subtype attributes
6001 -- should always cause freezing, even in default expressions, but
6002 -- the attribute may not have been marked as static yet (because in
6003 -- Resolve_Attribute, the call to Eval_Attribute follows the call of
6004 -- Freeze_Expression on the prefix).
6006 if In_Spec_Exp
6013 then
6017 -- Freeze type of expression if not frozen already
6025 -- Base type may be an derived numeric type that is frozen at
6026 -- the point of declaration, but first_subtype is still unfrozen.
6033 -- For entity name, freeze entity if not frozen already. A special
6034 -- exception occurs for an identifier that did not come from source.
6035 -- We don't let such identifiers freeze a non-internal entity, i.e.
6036 -- an entity that did come from source, since such an identifier was
6037 -- generated by the expander, and cannot have any semantic effect on
6038 -- the freezing semantics. For example, this stops the parameter of
6039 -- an initialization procedure from freezing the variable.
6046 then
6053 else
6057 -- For an allocator freeze designated type if not frozen already
6059 -- For an aggregate whose component type is an access type, freeze the
6060 -- designated type now, so that its freeze does not appear within the
6061 -- loop that might be created in the expansion of the aggregate. If the
6062 -- designated type is a private type without full view, the expression
6063 -- cannot contain an allocator, so the type is not frozen.
6065 -- For a function, we freeze the entity when the subprogram declaration
6066 -- is frozen, but a function call may appear in an initialization proc.
6067 -- before the declaration is frozen. We need to generate the extra
6068 -- formals, if any, to ensure that the expansion of the call includes
6069 -- the proper actuals. This only applies to Ada subprograms, not to
6070 -- imported ones.
6081 then
6085 when N_Selected_Component |
6086 N_Indexed_Component |
6087 N_Slice =>
6098 then
6109 then
6113 -- All done if nothing needs freezing
6118 then
6122 -- Examine the enclosing context by climbing the parent chain. The
6123 -- traversal serves two purposes - to detect scenarios where freezeing
6124 -- is not needed and to find the proper insertion point for the freeze
6125 -- nodes. Although somewhat similar to Insert_Actions, this traversal
6126 -- is freezing semantics-sensitive. Inserting freeze nodes blindly in
6127 -- the tree may result in types being frozen too early.
6130 loop
6133 -- If we don't have a parent, then we are not in a well-formed tree.
6134 -- This is an unusual case, but there are some legitimate situations
6135 -- in which this occurs, notably when the expressions in the range of
6136 -- a type declaration are resolved. We simply ignore the freeze
6137 -- request in this case. Is this right ???
6143 -- See if we have got to an appropriate point in the tree
6147 -- A special test for the exception of (RM 13.14(8)) for the case
6148 -- of per-object expressions (RM 3.8(18)) occurring in component
6149 -- definition or a discrete subtype definition. Note that we test
6150 -- for a component declaration which includes both cases we are
6151 -- interested in, and furthermore the tree does not have explicit
6152 -- nodes for either of these two constructs.
6156 -- The case we want to test for here is an identifier that is
6157 -- a per-object expression, this is either a discriminant that
6158 -- appears in a context other than the component declaration
6159 -- or it is a reference to the type of the enclosing construct.
6161 -- For either of these cases, we skip the freezing
6163 if not In_Spec_Expression
6166 then
6167 -- We recognize the discriminant case by just looking for
6168 -- a reference to a discriminant. It can only be one for
6169 -- the enclosing construct. Skip freezing in this case.
6174 -- For the case of a reference to the enclosing record,
6175 -- (or task or protected type), we look for a type that
6176 -- matches the current scope.
6183 -- If we have an enumeration literal that appears as the choice in
6184 -- the aggregate of an enumeration representation clause, then
6185 -- freezing does not occur (RM 13.14(10)).
6189 -- The case we are looking for is an enumeration literal
6193 then
6194 -- If enumeration literal appears directly as the choice,
6195 -- do not freeze (this is the normal non-overloaded case)
6199 then
6202 -- If enumeration literal appears as the name of function
6203 -- which is the choice, then also do not freeze. This
6204 -- happens in the overloaded literal case, where the
6205 -- enumeration literal is temporarily changed to a function
6206 -- call for overloading analysis purposes.
6209 and then
6211 and then
6213 then
6218 -- Normally if the parent is a handled sequence of statements,
6219 -- then the current node must be a statement, and that is an
6220 -- appropriate place to insert a freeze node.
6224 -- An exception occurs when the sequence of statements is for
6225 -- an expander generated body that did not do the usual freeze
6226 -- all operation. In this case we usually want to freeze
6227 -- outside this body, not inside it, and we skip past the
6228 -- subprogram body that we are inside.
6231 declare
6235 begin
6236 -- Freeze the entity only when it is declared inside the
6237 -- body of the expander generated procedure. This case
6238 -- is recognized by the scope of the entity or its type,
6239 -- which is either the spec for some enclosing body, or
6240 -- (in the case of init_procs, for which there are no
6241 -- separate specs) the current scope.
6247 or else
6249 then
6255 then
6260 -- An expression function may act as a completion of
6261 -- a function declaration. As such, it can reference
6262 -- entities declared between the two views:
6264 -- Hidden []; -- 1
6265 -- function F return ...;
6266 -- private
6267 -- function Hidden return ...;
6268 -- function F return ... is (Hidden); -- 2
6270 -- Refering to the example above, freezing the expression
6271 -- of F (2) would place Hidden's freeze node (1) in the
6272 -- wrong place. Avoid explicit freezing and let the usual
6273 -- scenarios do the job - for example, reaching the end
6274 -- of the private declarations.
6277 N_Expression_Function
6278 then
6281 -- Freeze outside the body
6283 else
6289 -- Here if normal case where we are in handled statement
6290 -- sequence and want to do the insertion right there.
6292 else
6296 -- If parent is a body or a spec or a block, then the current node
6297 -- is a statement or declaration and we can insert the freeze node
6298 -- before it.
6300 when N_Block_Statement |
6301 N_Entry_Body |
6302 N_Package_Body |
6303 N_Package_Specification |
6304 N_Protected_Body |
6305 N_Subprogram_Body |
6308 -- The expander is allowed to define types in any statements list,
6309 -- so any of the following parent nodes also mark a freezing point
6310 -- if the actual node is in a list of statements or declarations.
6312 when N_Abortable_Part |
6313 N_Accept_Alternative |
6314 N_And_Then |
6315 N_Case_Statement_Alternative |
6316 N_Compilation_Unit_Aux |
6317 N_Conditional_Entry_Call |
6318 N_Delay_Alternative |
6319 N_Elsif_Part |
6320 N_Entry_Call_Alternative |
6321 N_Exception_Handler |
6322 N_Extended_Return_Statement |
6323 N_Freeze_Entity |
6324 N_If_Statement |
6325 N_Or_Else |
6326 N_Selective_Accept |
6327 N_Triggering_Alternative =>
6331 -- Freeze nodes produced by an expression coming from the Actions
6332 -- list of a N_Expression_With_Actions node must remain within the
6333 -- Actions list. Inserting the freeze nodes further up the tree
6334 -- may lead to use before declaration issues in the case of array
6335 -- types.
6340 then
6344 -- Note: N_Loop_Statement is a special case. A type that appears
6345 -- in the source can never be frozen in a loop (this occurs only
6346 -- because of a loop expanded by the expander), so we keep on
6347 -- going. Otherwise we terminate the search. Same is true of any
6348 -- entity which comes from source. (if they have predefined type,
6349 -- that type does not appear to come from source, but the entity
6350 -- should not be frozen here).
6356 -- For all other cases, keep looking at parents
6362 -- We fall through the case if we did not yet find the proper
6363 -- place in the free for inserting the freeze node, so climb.
6368 -- If the expression appears in a record or an initialization procedure,
6369 -- the freeze nodes are collected and attached to the current scope, to
6370 -- be inserted and analyzed on exit from the scope, to insure that
6371 -- generated entities appear in the correct scope. If the expression is
6372 -- a default for a discriminant specification, the scope is still void.
6373 -- The expression can also appear in the discriminant part of a private
6374 -- or concurrent type.
6376 -- If the expression appears in a constrained subcomponent of an
6377 -- enclosing record declaration, the freeze nodes must be attached to
6378 -- the outer record type so they can eventually be placed in the
6379 -- enclosing declaration list.
6381 -- The other case requiring this special handling is if we are in a
6382 -- default expression, since in that case we are about to freeze a
6383 -- static type, and the freeze scope needs to be the outer scope, not
6384 -- the scope of the subprogram with the default parameter.
6386 -- For default expressions and other spec expressions in generic units,
6387 -- the Move_Freeze_Nodes mechanism (see sem_ch12.adb) takes care of
6388 -- placing them at the proper place, after the generic unit.
6391 or else Freeze_Outside
6396 then
6397 declare
6402 begin
6415 -- The current scope may be that of a constrained component of
6416 -- an enclosing record declaration, or of a loop of an enclosing
6417 -- quantified expression, which is above the current scope in the
6418 -- scope stack. Indeed in the context of a quantified expression,
6419 -- a scope is created and pushed above the current scope in order
6420 -- to emulate the loop-like behavior of the quantified expression.
6421 -- If the expression is within a top-level pragma, as for a pre-
6422 -- condition on a library-level subprogram, nothing to do.
6427 N_Quantified_Expression)
6428 then
6435 Freeze_Nodes;
6436 else
6446 -- Now we have the right place to do the freezing. First, a special
6447 -- adjustment, if we are in spec-expression analysis mode, these freeze
6448 -- actions must not be thrown away (normally all inserted actions are
6449 -- thrown away in this mode. However, the freeze actions are from static
6450 -- expressions and one of the important reasons we are doing this
6451 -- special analysis is to get these freeze actions. Therefore we turn
6452 -- off the In_Spec_Expression mode to propagate these freeze actions.
6453 -- This also means they get properly analyzed and expanded.
6457 -- Freeze the designated type of an allocator (RM 13.14(13))
6463 -- Freeze type of expression (RM 13.14(10)). Note that we took care of
6464 -- the enumeration representation clause exception in the loop above.
6470 -- Freeze name if one is present (RM 13.14(11))
6476 -- Restore In_Spec_Expression flag
6481 -----------------------------
6482 -- Freeze_Fixed_Point_Type --
6483 -----------------------------
6485 -- Certain fixed-point types and subtypes, including implicit base types
6486 -- and declared first subtypes, have not yet set up a range. This is
6487 -- because the range cannot be set until the Small and Size values are
6488 -- known, and these are not known till the type is frozen.
6490 -- To signal this case, Scalar_Range contains an unanalyzed syntactic range
6491 -- whose bounds are unanalyzed real literals. This routine will recognize
6492 -- this case, and transform this range node into a properly typed range
6493 -- with properly analyzed and resolved values.
6511 -- Returns size of type with given bounds. Also leaves these
6512 -- bounds set as the current bounds of the Typ.
6514 -----------
6515 -- Fsize --
6516 -----------
6519 begin
6525 -- Start of processing for Freeze_Fixed_Point_Type
6527 begin
6528 -- If Esize of a subtype has not previously been set, set it now
6535 else
6540 -- Immediate return if the range is already analyzed. This means that
6541 -- the range is already set, and does not need to be computed by this
6542 -- routine.
6548 -- Immediate return if either of the bounds raises Constraint_Error
6552 then
6559 -- Ordinary fixed-point case
6563 -- For the ordinary fixed-point case, we are allowed to fudge the
6564 -- end-points up or down by small. Generally we prefer to fudge up,
6565 -- i.e. widen the bounds for non-model numbers so that the end points
6566 -- are included. However there are cases in which this cannot be
6567 -- done, and indeed cases in which we may need to narrow the bounds.
6568 -- The following circuit makes the decision.
6570 -- Note: our terminology here is that Incl_EP means that the bounds
6571 -- are widened by Small if necessary to include the end points, and
6572 -- Excl_EP means that the bounds are narrowed by Small to exclude the
6573 -- end-points if this reduces the size.
6575 -- Note that in the Incl case, all we care about is including the
6576 -- end-points. In the Excl case, we want to narrow the bounds as
6577 -- much as permitted by the RM, to give the smallest possible size.
6594 begin
6595 -- First step. Base types are required to be symmetrical. Right
6596 -- now, the base type range is a copy of the first subtype range.
6597 -- This will be corrected before we are done, but right away we
6598 -- need to deal with the case where both bounds are non-negative.
6599 -- In this case, we set the low bound to the negative of the high
6600 -- bound, to make sure that the size is computed to include the
6601 -- required sign. Note that we do not need to worry about the
6602 -- case of both bounds negative, because the sign will be dealt
6603 -- with anyway. Furthermore we can't just go making such a bound
6604 -- symmetrical, since in a twos-complement system, there is an
6605 -- extra negative value which could not be accommodated on the
6606 -- positive side.
6611 then
6616 -- Compute the fudged bounds. If the number is a model number,
6617 -- then we do nothing to include it, but we are allowed to backoff
6618 -- to the next adjacent model number when we exclude it. If it is
6619 -- not a model number then we straddle the two values with the
6620 -- model numbers on either side.
6626 else
6630 -- The low value excluding the end point is Small greater, but
6631 -- we do not do this exclusion if the low value is positive,
6632 -- since it can't help the size and could actually hurt by
6633 -- crossing the high bound.
6638 -- If the value went from negative to zero, then we have the
6639 -- case where Loval_Incl_EP is the model number just below
6640 -- zero, so we want to stick to the negative value for the
6641 -- base type to maintain the condition that the size will
6642 -- include signed values.
6646 then
6650 else
6654 -- Similar processing for upper bound and high value
6660 else
6666 else
6670 -- One further adjustment is needed. In the case of subtypes, we
6671 -- cannot go outside the range of the base type, or we get
6672 -- peculiarities, and the base type range is already set. This
6673 -- only applies to the Incl values, since clearly the Excl values
6674 -- are already as restricted as they are allowed to be.
6681 -- Get size including and excluding end points
6686 -- No need to exclude end-points if it does not reduce size
6696 -- Now we set the actual size to be used. We want to use the
6697 -- bounds fudged up to include the end-points but only if this
6698 -- can be done without violating a specifically given size
6699 -- size clause or causing an unacceptable increase in size.
6701 -- Case of size clause given
6705 -- Use the inclusive size only if it is consistent with
6706 -- the explicitly specified size.
6713 -- If the inclusive size is too large, we try excluding
6714 -- the end-points (will be caught later if does not work).
6716 else
6722 -- Case of size clause not given
6724 else
6725 -- If we have a base type whose corresponding first subtype
6726 -- has an explicit size that is large enough to include our
6727 -- end-points, then do so. There is no point in working hard
6728 -- to get a base type whose size is smaller than the specified
6729 -- size of the first subtype.
6735 then
6740 -- If excluding the end-points makes the size smaller and
6741 -- results in a size of 8,16,32,64, then we take the smaller
6742 -- size. For the 64 case, this is compulsory. For the other
6743 -- cases, it seems reasonable. We like to include end points
6744 -- if we can, but not at the expense of moving to the next
6745 -- natural boundary of size.
6749 then
6754 -- Otherwise we can definitely include the end points
6756 else
6762 -- One pathological case: normally we never fudge a low bound
6763 -- down, since it would seem to increase the size (if it has
6764 -- any effect), but for ranges containing single value, or no
6765 -- values, the high bound can be small too large. Consider:
6767 -- type t is delta 2.0**(-14)
6768 -- range 131072.0 .. 0;
6770 -- That lower bound is *just* outside the range of 32 bits, and
6771 -- does need fudging down in this case. Note that the bounds
6772 -- will always have crossed here, since the high bound will be
6773 -- fudged down if necessary, as in the case of:
6775 -- type t is delta 2.0**(-14)
6776 -- range 131072.0 .. 131072.0;
6778 -- So we detect the situation by looking for crossed bounds,
6779 -- and if the bounds are crossed, and the low bound is greater
6780 -- than zero, we will always back it off by small, since this
6781 -- is completely harmless.
6788 -- And of course, we need to do exactly the same parallel
6789 -- fudge for flat ranges in the negative region.
6802 -- For the decimal case, none of this fudging is required, since there
6803 -- are no end-point problems in the decimal case (the end-points are
6804 -- always included).
6806 else
6810 -- At this stage, the actual size has been calculated and the proper
6811 -- required bounds are stored in the low and high bounds.
6815 Error_Msg_N
6817 Typ);
6821 -- Check size against explicit given size
6827 Error_Msg_NE
6831 else
6835 -- Increase size to next natural boundary if no size clause given
6837 else
6844 else
6852 -- If we have a base type, then expand the bounds so that they extend to
6853 -- the full width of the allocated size in bits, to avoid junk range
6854 -- checks on intermediate computations.
6861 -- Final step is to reanalyze the bounds using the proper type
6862 -- and set the Corresponding_Integer_Value fields of the literals.
6868 -- Resolve with universal fixed if the base type, and the base type if
6869 -- it is a subtype. Note we can't resolve the base type with itself,
6870 -- that would be a reference before definition.
6874 else
6878 -- Set corresponding integer value for bound
6880 Set_Corresponding_Integer_Value
6883 -- Similar processing for high bound
6891 else
6895 Set_Corresponding_Integer_Value
6898 -- Set type of range to correspond to bounds
6902 -- Set Esize to calculated size if not set already
6908 -- Set RM_Size if not already set. If already set, check value
6910 declare
6913 begin
6918 Error_Msg_NE
6923 else
6929 ------------------
6930 -- Freeze_Itype --
6931 ------------------
6936 begin
6945 --------------------------
6946 -- Freeze_Static_Object --
6947 --------------------------
6952 -- Exception raised if the type of a static object cannot be made
6953 -- static. This happens if the type depends on non-global objects.
6956 -- Called to ensure that an expression used as part of a type definition
6957 -- is statically allocatable, which means that the expression type is
6958 -- statically allocatable, and the expression is either static, or a
6959 -- reference to a library level constant.
6962 -- Called to mark a type as static, checking that it is possible
6963 -- to set the type as static. If it is not possible, then the
6964 -- exception Cannot_Be_Static is raised.
6966 -----------------------------
6967 -- Ensure_Expression_Is_SA --
6968 -----------------------------
6973 begin
6985 then
6993 -----------------------
6994 -- Ensure_Type_Is_SA --
6995 -----------------------
7001 begin
7002 -- If type is library level, we are all set
7008 -- We are also OK if the type already marked as statically allocated,
7009 -- which means we processed it before.
7015 -- Mark type as statically allocated
7019 -- Check that it is safe to statically allocate this type
7037 declare
7041 begin
7053 else
7062 then
7081 else
7086 -- Start of processing for Freeze_Static_Object
7088 begin
7091 exception
7094 -- If the object that cannot be static is imported or exported, then
7095 -- issue an error message saying that this object cannot be imported
7096 -- or exported. If it has an address clause it is an overlay in the
7097 -- current partition and the static requirement is not relevant.
7098 -- Do not issue any error message when ignoring rep clauses.
7105 Error_Msg_N
7109 -- Otherwise must be exported, something is wrong if compiler
7110 -- is marking something as statically allocated which cannot be).
7113 Error_Msg_N
7118 -----------------------
7119 -- Freeze_Subprogram --
7120 -----------------------
7126 begin
7127 -- Subprogram may not have an address clause unless it is imported
7131 Error_Msg_N
7138 -- Reset the Pure indication on an imported subprogram unless an
7139 -- explicit Pure_Function pragma was present or the subprogram is an
7140 -- intrinsic. We do this because otherwise it is an insidious error
7141 -- to call a non-pure function from pure unit and have calls
7142 -- mysteriously optimized away. What happens here is that the Import
7143 -- can bypass the normal check to ensure that pure units call only pure
7144 -- subprograms.
7146 -- The reason for the intrinsic exception is that in general, intrinsic
7147 -- functions (such as shifts) are pure anyway. The only exceptions are
7148 -- the intrinsics in GNAT.Source_Info, and that unit is not marked Pure
7149 -- in any case, so no problem arises.
7155 then
7159 -- For non-foreign convention subprograms, this is where we create
7160 -- the extra formals (for accessibility level and constrained bit
7161 -- information). We delay this till the freeze point precisely so
7162 -- that we know the convention.
7168 -- If this is convention Ada and a Valued_Procedure, that's odd
7173 and then Warn_On_Export_Import
7174 then
7175 Error_Msg_N
7180 -- Case of foreign convention
7182 else
7185 -- For foreign conventions, warn about return of unconstrained array
7190 -- If no return type, probably some other error, e.g. a
7191 -- missing full declaration, so ignore.
7196 -- If the return type is generic, we have emitted a warning
7197 -- earlier on, and there is nothing else to check here. Specific
7198 -- instantiations may lead to erroneous behavior.
7203 -- Display warning if returning unconstrained array
7208 -- Check appropriate warning is enabled (should we check for
7209 -- Warnings (Off) on specific entities here, probably so???)
7211 and then Warn_On_Export_Import
7213 -- Exclude the VM case, since return of unconstrained arrays
7214 -- is properly handled in both the JVM and .NET cases.
7217 then
7218 Error_Msg_N
7225 -- If any of the formals for an exported foreign convention
7226 -- subprogram have defaults, then emit an appropriate warning since
7227 -- this is odd (default cannot be used from non-Ada code)
7232 if Warn_On_Export_Import
7234 then
7235 Error_Msg_N
7245 -- Pragma Inline_Always is disallowed for dispatching subprograms
7246 -- because the address of such subprograms is saved in the dispatch
7247 -- table to support dispatching calls, and dispatching calls cannot
7248 -- be inlined. This is consistent with the restriction against using
7249 -- 'Access or 'Address on an Inline_Always subprogram.
7253 then
7254 Error_Msg_N
7258 -- Because of the implicit representation of inherited predefined
7259 -- operators in the front-end, the overriding status of the operation
7260 -- may be affected when a full view of a type is analyzed, and this is
7261 -- not captured by the analysis of the corresponding type declaration.
7262 -- Therefore the correctness of a not-overriding indicator must be
7263 -- rechecked when the subprogram is frozen.
7267 then
7272 ----------------------
7273 -- Is_Fully_Defined --
7274 ----------------------
7277 begin
7286 then
7287 -- Verify that the record type has no components with private types
7288 -- without completion.
7290 declare
7293 begin
7305 -- For the designated type of an access to subprogram, all types in
7306 -- the profile must be fully defined.
7309 declare
7312 begin
7325 else
7331 ---------------------------------
7332 -- Process_Default_Expressions --
7333 ---------------------------------
7335 procedure Process_Default_Expressions
7338 is
7345 begin
7348 -- A subprogram instance and its associated anonymous subprogram share
7349 -- their signature. The default expression functions are defined in the
7350 -- wrapper packages for the anonymous subprogram, and should not be
7351 -- generated again for the instance.
7356 then
7364 -- We work with a copy of the default expression because we
7365 -- do not want to disturb the original, since this would mess
7366 -- up the conformance checking.
7370 -- The analysis of the expression may generate insert actions,
7371 -- which of course must not be executed. We wrap those actions
7372 -- in a procedure that is not called, and later on eliminated.
7373 -- The following cases have no side-effects, and are analyzed
7374 -- directly.
7378 N_Integer_Literal,
7379 N_Character_Literal,
7380 N_String_Literal,
7381 N_Real_Literal)
7385 then
7386 -- If there is no default function, we must still do a full
7387 -- analyze call on the default value, to ensure that all error
7388 -- checks are performed, e.g. those associated with static
7389 -- evaluation. Note: this branch will always be taken if the
7390 -- analyzer is turned off (but we still need the error checks).
7392 -- Note: the setting of parent here is to meet the requirement
7393 -- that we can only analyze the expression while attached to
7394 -- the tree. Really the requirement is that the parent chain
7395 -- be set, we don't actually need to be in the tree.
7400 -- Default expressions are resolved with their own type if the
7401 -- context is generic, to avoid anomalies with private types.
7405 else
7409 -- If that resolved expression will raise constraint error,
7410 -- then flag the default value as raising constraint error.
7411 -- This allows a proper error message on the calls.
7417 -- If the default is a parameterless call, we use the name of
7418 -- the called function directly, and there is no body to build.
7422 then
7425 -- Else construct and analyze the body of a wrapper procedure
7426 -- that contains an object declaration to hold the expression.
7427 -- Given that this is done only to complete the analysis, it
7428 -- simpler to build a procedure than a function which might
7429 -- involve secondary stack expansion.
7431 else
7434 Dbody :=
7436 Specification =>
7443 Object_Definition =>
7447 Handled_Statement_Sequence =>
7464 ----------------------------------------
7465 -- Set_Component_Alignment_If_Not_Set --
7466 ----------------------------------------
7469 begin
7470 -- Ignore if not base type, subtypes don't need anything
7476 -- Do not override existing representation
7487 else
7488 Set_Component_Alignment
7494 --------------------------
7495 -- Set_SSO_From_Default --
7496 --------------------------
7499 begin
7502 then
7504 or else
7507 -- For a record type, if native bit order is specified explicitly,
7508 -- then never set reverse SSO from default.
7510 and then not
7514 then
7515 -- If flags cause reverse storage order, then set the result. Note
7516 -- that we would have ignored the pragma setting the non default
7517 -- storage order in any case, hence the assertion at this point.
7522 -- For a record type, also set reversed bit order. Note that if
7523 -- a bit order has been specified explicitly, then this is a
7524 -- no-op, as per the guard above.
7533 ------------------
7534 -- Undelay_Type --
7535 ------------------
7538 begin
7542 -- Since we don't want T to have a Freeze_Node, we don't want its
7543 -- Full_View or Corresponding_Record_Type to have one either.
7545 -- ??? Fundamentally, this whole handling is unpleasant. What we really
7546 -- want is to be sure that for an Itype that's part of record R and is a
7547 -- subtype of type T, that it's frozen after the later of the freeze
7548 -- points of R and T. We have no way of doing that directly, so what we
7549 -- do is force most such Itypes to be frozen as part of freezing R via
7550 -- this procedure and only delay the ones that need to be delayed
7551 -- (mostly the designated types of access types that are defined as part
7552 -- of the record).
7558 then
7566 then
7571 ------------------
7572 -- Warn_Overlay --
7573 ------------------
7575 procedure Warn_Overlay
7579 is
7581 -- The object to which the address clause applies
7587 begin
7588 -- No warning if address clause overlay warnings are off
7594 -- No warning if there is an explicit initialization
7602 -- We only give the warning for non-imported entities of a type for
7603 -- which a non-null base init proc is defined, or for objects of access
7604 -- types with implicit null initialization, or when Normalize_Scalars
7605 -- applies and the type is scalar or a string type (the latter being
7606 -- tested for because predefined String types are initialized by inline
7607 -- code rather than by an init_proc). Note that we do not give the
7608 -- warning for Initialize_Scalars, since we suppressed initialization
7609 -- in this case. Also, do not warn if Suppress_Initialization is set.
7619 then
7622 then
7627 then
7634 then
7641 -- A function call (most likely to To_Address) is probably not an
7642 -- overlay, so skip warning. Ditto if the function call was inlined
7643 -- and transformed into an entity.
7651 -- If a pragma Import follows, we assume that it is for the current
7652 -- target of the address clause, and skip the warning.
7657 then
7663 Error_Msg_N
7665 Nam);
7666 else
7667 Error_Msg_N
7669 Nam);
7672 -- Add friendly warning if initialization comes from a packed array
7673 -- component.
7676 declare
7679 begin
7684 then
7688 then
7689 Error_Msg_NE
7694 else
7701 Error_Msg_N
7704 Nam);