| blob | fb4241a40aa2a64dabc260a1409eadf7b100b5bf |
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 -------------------
1827 -- List of freezing actions, left at No_List if none
1830 -- This flag gets set to true for a variable with default initialization
1833 -- N is a freezing action to be appended to the Result
1836 -- If Loc is a freeze_entity that appears after the last declaration
1837 -- in the scope, inhibit error messages on late completion.
1840 -- Check that an Access or Unchecked_Access attribute with a prefix
1841 -- which is the current instance type can only be applied when the type
1842 -- is limited.
1845 -- Give warning for modulus of 8, 16, 32, or 64 given as an explicit
1846 -- integer literal without an explicit corresponding size clause. The
1847 -- caller has checked that Utype is a modular integer type.
1850 -- Freeze array type, including freezing index and component types
1853 -- Create Freeze_Generic_Entity nodes for types declared in a generic
1854 -- package. Recurse on inner generic packages.
1857 -- Freeze record type, including freezing component types, and freezing
1858 -- primitive operations if this is a tagged type.
1861 -- Determine whether an arbitrary entity is subject to Boolean aspect
1862 -- Import and its value is specified as True.
1865 -- If E is an entity for an imported subprogram with pre/post-conditions
1866 -- then this procedure will create a wrapper to ensure that proper run-
1867 -- time checking of the pre/postconditions. See body for details.
1869 -------------------
1870 -- Add_To_Result --
1871 -------------------
1874 begin
1877 else
1882 ----------------------------
1883 -- After_Last_Declaration --
1884 ----------------------------
1888 begin
1894 else
1897 else
1902 ----------------------------
1903 -- Check_Current_Instance --
1904 ----------------------------
1909 -- Determine whether Typ is compatible with the rules for aliased
1910 -- views of types as defined in RM 3.10 in the various dialects.
1913 -- Process routine to apply check to given node
1915 -----------------------------
1916 -- Is_Aliased_View_Of_Type --
1917 -----------------------------
1922 begin
1923 -- Common case
1927 then
1930 -- The following paragraphs describe what a legal aliased view of
1931 -- a type is in the various dialects of Ada.
1933 -- Ada 95
1935 -- The current instance of a limited type, and a formal parameter
1936 -- or generic formal object of a tagged type.
1938 -- Ada 95 limited type
1939 -- * Type with reserved word "limited"
1940 -- * A protected or task type
1941 -- * A composite type with limited component
1946 -- Ada 2005
1948 -- The current instance of a limited tagged type, a protected
1949 -- type, a task type, or a type that has the reserved word
1950 -- "limited" in its full definition ... a formal parameter or
1951 -- generic formal object of a tagged type.
1953 -- Ada 2005 limited type
1954 -- * Type with reserved word "limited", "synchronized", "task"
1955 -- or "protected"
1956 -- * A composite type with limited component
1957 -- * A derived type whose parent is a non-interface limited type
1960 return
1962 or else
1967 -- Ada 2012 and beyond
1969 -- The current instance of an immutably limited type ... a formal
1970 -- parameter or generic formal object of a tagged type.
1972 -- Ada 2012 limited type
1973 -- * Type with reserved word "limited", "synchronized", "task"
1974 -- or "protected"
1975 -- * A composite type with limited component
1976 -- * A derived type whose parent is a non-interface limited type
1977 -- * An incomplete view
1979 -- Ada 2012 immutably limited type
1980 -- * Explicitly limited record type
1981 -- * Record extension with "limited" present
1982 -- * Non-formal limited private type that is either tagged
1983 -- or has at least one access discriminant with a default
1984 -- expression
1985 -- * Task type, protected type or synchronized interface
1986 -- * Type derived from immutably limited type
1988 else
1989 return
1995 -------------
1996 -- Process --
1997 -------------
2000 begin
2004 Name_Unchecked_Access)
2008 then
2010 Error_Msg_N
2013 else
2014 Error_Msg_N
2022 else
2032 -- Local variables
2037 -- Start of processing for Check_Current_Instance
2039 begin
2045 ------------------------------
2046 -- Check_Suspicious_Modulus --
2047 ------------------------------
2052 begin
2058 declare
2061 begin
2063 declare
2067 begin
2069 declare
2073 begin
2074 -- First case, modulus and size are the same. This
2075 -- happens if you have something like mod 32, with
2076 -- an explicit size of 32, this is for sure a case
2077 -- where the warning is given, since it is seems
2078 -- very unlikely that someone would want e.g. a
2079 -- five bit type stored in 32 bits. It is much
2080 -- more likely they wanted a 32-bit type.
2085 -- Second case, the modulus is 32 or 64 and no
2086 -- size clause is present. This is a less clear
2087 -- case for giving the warning, but in the case
2088 -- of 32/64 (5-bit or 6-bit types) these seem rare
2089 -- enough that it is a likely error (and in any
2090 -- case using 2**5 or 2**6 in these cases seems
2091 -- clearer. We don't include 8 or 16 here, simply
2092 -- because in practice 3-bit and 4-bit types are
2093 -- more common and too many false positives if
2094 -- we warn in these cases.
2098 then
2101 -- No warning needed
2103 else
2107 -- If we fall through, give warning
2110 Error_Msg_N
2112 Modulus);
2121 -----------------------
2122 -- Freeze_Array_Type --
2123 -----------------------
2131 -- Set true if any of the index types is an enumeration type with a
2132 -- non-standard representation.
2134 begin
2143 then
2150 -- Processing that is done only for base types
2154 -- Deal with default setting of reverse storage order
2158 -- Propagate flags for component type
2162 then
2170 -- Warn for pragma Pack overriding foreign convention
2174 then
2175 declare
2180 begin
2184 Error_Msg_N
2186 PP);
2188 Error_Msg_N
2195 -- If packing was requested or if the component size was
2196 -- set explicitly, then see if bit packing is required. This
2197 -- processing is only done for base types, since all of the
2198 -- representation aspects involved are type-related.
2200 -- This is not just an optimization, if we start processing the
2201 -- subtypes, they interfere with the settings on the base type
2202 -- (this is because Is_Packed has a slightly different meaning
2203 -- before and after freezing).
2205 declare
2209 begin
2213 then
2222 else
2225 -- We can set the component size if it is less than 16,
2226 -- rounding it up to the next storage unit size.
2232 else
2236 -- Set component size up to match alignment if it would
2237 -- otherwise be less than the alignment. This deals with
2238 -- cases of types whose alignment exceeds their size (the
2239 -- padded type cases).
2242 declare
2244 begin
2252 -- Case of component size that may result in packing
2255 declare
2261 Get_Attribute_Definition_Clause
2263 begin
2264 -- Warn if we have pack and component size so that the
2265 -- pack is ignored.
2267 -- Note: here we must check for the presence of a
2268 -- component size before checking for a Pack pragma to
2269 -- deal with the case where the array type is a derived
2270 -- type whose parent is currently private.
2274 and then Warn_On_Redundant_Constructs
2275 then
2277 Error_Msg_NE
2279 Error_Msg_N
2285 -- Set component size if not already set by a component
2286 -- size clause.
2292 -- Check for base type of 8, 16, 32 bits, where an
2293 -- unsigned subtype has a length one less than the
2294 -- base type (e.g. Natural subtype of Integer).
2296 -- In such cases, if a component size was not set
2297 -- explicitly, then generate a warning.
2303 then
2307 Error_Msg_N
2310 Error_Msg_N
2316 -- Actual packing is not needed for 8, 16, 32, 64. Also
2317 -- not needed for 24 if alignment is 1.
2324 then
2325 -- Here the array was requested to be packed, but
2326 -- the packing request had no effect, so Is_Packed
2327 -- is reset.
2329 -- Note: semantically this means that we lose track
2330 -- of the fact that a derived type inherited a pragma
2331 -- Pack that was non- effective, but that seems fine.
2333 -- We regard a Pack pragma as a request to set a
2334 -- representation characteristic, and this request
2335 -- may be ignored.
2342 then
2346 -- In all other cases, packing is indeed needed
2348 else
2357 -- Check for Atomic_Components or Aliased with unsuitable packing
2358 -- or explicit component size clause given.
2361 or else
2363 and then
2365 then
2369 -- Outputs error messages for incorrect CS clause or pragma
2370 -- Pack for aliased or atomic components (T is "aliased" or
2371 -- "atomic");
2373 -----------------
2374 -- Complain_CS --
2375 -----------------
2378 begin
2380 Clause :=
2381 Get_Attribute_Definition_Clause
2385 Error_Msg_N
2389 Error_Msg_N
2392 else
2393 Error_Msg_N
2398 else
2399 Error_Msg_N
2407 -- Start of processing for Alias_Atomic_Check
2409 begin
2410 -- If object size of component type isn't known, we cannot
2411 -- be sure so we defer to the back end.
2416 -- Case where component size has no effect. First check for
2417 -- object size of component type multiple of the storage
2418 -- unit size.
2422 -- OK in both packing case and component size case if RM
2423 -- size is known and static and same as the object size.
2425 and then
2429 -- Or if we have an explicit component size clause and
2430 -- the component size and object size are equal.
2432 or else
2435 then
2440 then
2445 then
2451 -- Warn for case of atomic type
2457 then
2458 Error_Msg_NE
2473 -- Check for scalar storage order
2475 declare
2477 begin
2478 Check_Component_Storage_Order
2481 ADC => Get_Attribute_Definition_Clause
2483 Attribute_Scalar_Storage_Order),
2487 -- Processing that is done only for subtypes
2489 else
2490 -- Acquire alignment from base type
2498 -- Specific checks for bit-packed arrays
2502 -- Check number of elements for bit packed arrays that come from
2503 -- source and have compile time known ranges. The bit-packed
2504 -- arrays circuitry does not support arrays with more than
2505 -- Integer'Last + 1 elements, and when this restriction is
2506 -- violated, causes incorrect data access.
2508 -- For the case where this is not compile time known, a run-time
2509 -- check should be generated???
2512 declare
2518 begin
2524 -- Never generate an error if any index is of a generic
2525 -- type. We will check this in instances.
2532 Ilen :=
2534 Prefix =>
2539 -- No attempt is made to check number of elements
2540 -- if not compile time known.
2553 then
2554 Error_Msg_N
2561 -- Check size
2564 declare
2570 begin
2571 -- It is not clear if it is possible to have no size clause
2572 -- at this stage, but it is not worth worrying about. Post
2573 -- error on the entity name in the size clause if present,
2574 -- else on the type entity itself.
2578 else
2585 -- If any of the index types was an enumeration type with a
2586 -- non-standard rep clause, then we indicate that the array type
2587 -- is always packed (even if it is not bit packed).
2596 -- If the array is packed, we must create the packed array type to be
2597 -- used to actually implement the type. This is only needed for real
2598 -- array types (not for string literal types, since they are present
2599 -- only for the front end).
2603 then
2607 -- Size information of packed array type is copied to the array
2608 -- type, since this is really the representation. But do not
2609 -- override explicit existing size values. If the ancestor subtype
2610 -- is constrained the Packed_Array_Impl_Type will be inherited
2611 -- from it, but the size may have been provided already, and
2612 -- must not be overridden either.
2615 and then
2618 then
2628 -- For non-packed arrays set the alignment of the array to the
2629 -- alignment of the component type if it is unknown. Skip this
2630 -- in atomic case (atomic arrays may need larger alignments).
2639 then
2644 -----------------------------
2645 -- Freeze_Generic_Entities --
2646 -----------------------------
2653 begin
2672 ------------------------
2673 -- Freeze_Record_Type --
2674 ------------------------
2686 -- Set True if the record type scope Rec has been pushed on the scope
2687 -- stack. Needed for the analysis of delayed aspects specified to the
2688 -- components of Rec.
2691 -- Scalar_Storage_Order attribute definition clause for the record
2694 -- Set True if we find at least one component with no component
2695 -- clause (used to warn about useless Pack pragmas).
2698 -- Set True if we find at least one component with a component
2699 -- clause (used to warn about useless Bit_Order pragmas, and also
2700 -- to detect cases where Implicit_Packing may have an effect).
2703 -- Set True if we find at least one component which is aliased. This
2704 -- is used to prevent Implicit_Packing of the record, since packing
2705 -- cannot modify the size of alignment of an aliased component.
2708 -- Set True if we find at least one component whose type has a
2709 -- Scalar_Storage_Order attribute definition clause.
2712 -- Set False if we encounter a component of a non-scalar type
2716 -- Accumulates total RM_Size values and total Esize values of all
2717 -- scalar components. Used for processing of Implicit_Packing.
2720 -- If N is an allocator, possibly wrapped in one or more level of
2721 -- qualified expression(s), return the inner allocator node, else
2722 -- return Empty.
2725 -- If the component subtype is an access to a constrained subtype of
2726 -- an already frozen type, make the subtype frozen as well. It might
2727 -- otherwise be frozen in the wrong scope, and a freeze node on
2728 -- subtype has no effect. Similarly, if the component subtype is a
2729 -- regular (not protected) access to subprogram, set the anonymous
2730 -- subprogram type to frozen as well, to prevent an out-of-scope
2731 -- freeze node at some eventual point of call. Protected operations
2732 -- are handled elsewhere.
2735 -- Make sure that all types mentioned in Discrete_Choices of the
2736 -- variants referenceed by the Variant_Part VP are frozen. This is
2737 -- a recursive routine to deal with nested variants.
2739 ---------------------
2740 -- Check_Allocator --
2741 ---------------------
2745 begin
2747 loop
2752 else
2758 -----------------
2759 -- Check_Itype --
2760 -----------------
2765 begin
2768 then
2771 -- In addition, add an Itype_Reference to ensure that the
2772 -- access subtype is elaborated early enough. This cannot be
2773 -- done if the subtype may depend on discriminants.
2778 then
2786 then
2791 ------------------------------------
2792 -- Freeze_Choices_In_Variant_Part --
2793 ------------------------------------
2802 begin
2803 -- Loop through variants
2808 -- Loop through choices, checking that all types are frozen
2814 then
2821 -- Check for nested variant part to process
2835 -- Start of processing for Freeze_Record_Type
2837 begin
2838 -- Deal with delayed aspect specifications for components. The
2839 -- analysis of the aspect is required to be delayed to the freeze
2840 -- point, thus we analyze the pragma or attribute definition
2841 -- clause in the tree at this point. We also analyze the aspect
2842 -- specification node at the freeze point when the aspect doesn't
2843 -- correspond to pragma/attribute definition clause.
2849 then
2854 -- The visibility to the discriminants must be restored in
2855 -- order to properly analyze the aspects.
2868 -- Pop the scope if Rec scope has been pushed on the scope stack
2869 -- during the delayed aspect analysis process.
2876 Pop_Scope;
2879 -- Freeze components and embedded subtypes
2888 -- Handle the component and discriminant case
2891 declare
2894 begin
2895 -- Freezing a record type freezes the type of each of its
2896 -- components. However, if the type of the component is
2897 -- part of this record, we do not want or need a separate
2898 -- Freeze_Node. Note that Is_Itype is wrong because that's
2899 -- also set in private type cases. We also can't check for
2900 -- the Scope being exactly Rec because of private types and
2901 -- record extensions.
2906 then
2912 -- Warn for pragma Pack overriding foreign convention
2917 -- Don't warn for aliased components, since override
2918 -- cannot happen in that case.
2921 then
2922 declare
2927 begin
2931 Error_Msg_N
2933 PP);
2935 Error_Msg_NE
2942 -- Check for error of component clause given for variable
2943 -- sized type. We have to delay this test till this point,
2944 -- since the component type has to be frozen for us to know
2945 -- if it is variable length.
2950 -- We omit this test in a generic context, it will be
2951 -- applied at instantiation time.
2956 -- Also omit this test in CodePeer mode, since we do not
2957 -- have sufficient info on size and rep clauses.
2962 -- Do the check
2964 elsif not
2965 Size_Known_At_Compile_Time
2967 then
2968 Error_Msg_N
2973 else
2977 -- Case of component requires byte alignment
2981 -- Set the enclosing record to also require byte align
2985 -- Check for component clause that is inconsistent with
2986 -- the required byte boundary alignment.
2991 then
2992 Error_Msg_N
3000 -- Gather data for possible Implicit_Packing later. Note that at
3001 -- this stage we might be dealing with a real component, or with
3002 -- an implicit subtype declaration.
3006 else
3007 Scalar_Component_Total_RM_Size :=
3009 Scalar_Component_Total_Esize :=
3013 -- If the component is an Itype with Delayed_Freeze and is either
3014 -- a record or array subtype and its base type has not yet been
3015 -- frozen, we must remove this from the entity list of this record
3016 -- and put it on the entity list of the scope of its base type.
3017 -- Note that we know that this is not the type of a component
3018 -- since we cleared Has_Delayed_Freeze for it in the previous
3019 -- loop. Thus this must be the Designated_Type of an access type,
3020 -- which is the type of a component.
3028 then
3029 declare
3033 begin
3034 -- We have a difficult case to handle here. Suppose Rec is
3035 -- subtype being defined in a subprogram that's created as
3036 -- part of the freezing of Rec'Base. In that case, we know
3037 -- that Comp'Base must have already been frozen by the time
3038 -- we get to elaborate this because Gigi doesn't elaborate
3039 -- any bodies until it has elaborated all of the declarative
3040 -- part. But Is_Frozen will not be set at this point because
3041 -- we are processing code in lexical order.
3043 -- We detect this case by going up the Scope chain of Rec
3044 -- and seeing if we have a subprogram scope before reaching
3045 -- the top of the scope chain or that of Comp'Base. If we
3046 -- do, then mark that Comp'Base will actually be frozen. If
3047 -- so, we merely undelay it.
3063 else
3066 else
3070 -- Insert in entity list of scope of base type (which
3071 -- must be an enclosing scope, because still unfrozen).
3077 -- If the component is an access type with an allocator as default
3078 -- value, the designated type will be frozen by the corresponding
3079 -- expression in init_proc. In order to place the freeze node for
3080 -- the designated type before that for the current record type,
3081 -- freeze it now.
3083 -- Same process if the component is an array of access types,
3084 -- initialized with an aggregate. If the designated type is
3085 -- private, it cannot contain allocators, and it is premature
3086 -- to freeze the type, so we check for this as well.
3091 then
3092 declare
3096 begin
3099 -- If component is pointer to a class-wide type, freeze
3100 -- the specific type in the expression being allocated.
3101 -- The expression may be a subtype indication, in which
3102 -- case freeze the subtype mark.
3104 if Is_Class_Wide_Type
3106 then
3108 Freeze_And_Append
3110 elsif
3112 then
3113 Freeze_And_Append
3121 else
3122 Freeze_And_Append
3130 then
3133 -- Freeze the designated type when initializing a component with
3134 -- an aggregate in case the aggregate contains allocators.
3136 -- type T is ...;
3137 -- type T_Ptr is access all T;
3138 -- type T_Array is array ... of T_Ptr;
3140 -- type Rec is record
3141 -- Comp : T_Array := (others => ...);
3142 -- end record;
3146 then
3147 declare
3150 Designated_Type
3153 begin
3154 -- The only case when this sort of freezing is not done is
3155 -- when the designated type is class-wide and the root type
3156 -- is the record owning the component. This scenario results
3157 -- in a circularity because the class-wide type requires
3158 -- primitives that have not been created yet as the root
3159 -- type is in the process of being frozen.
3161 -- type Rec is tagged;
3162 -- type Rec_Ptr is access all Rec'Class;
3163 -- type Rec_Array is array ... of Rec_Ptr;
3165 -- type Rec is record
3166 -- Comp : Rec_Array := (others => ...);
3167 -- end record;
3171 then
3179 then
3189 SSO_ADC := Get_Attribute_Definition_Clause
3192 -- Check consistent attribute setting on component types
3194 declare
3196 begin
3199 Check_Component_Storage_Order
3209 -- Deal with default setting of reverse storage order
3213 -- Now deal with reverse storage order/bit order issues
3217 -- Check compatibility of Scalar_Storage_Order with Bit_Order, if
3218 -- the former is specified.
3222 -- Note: report error on Rec, not on SSO_ADC, as ADC may apply
3223 -- to some ancestor type.
3226 Error_Msg_N
3231 -- Warn if there is an Scalar_Storage_Order attribute definition
3232 -- clause but no component clause, no component that itself has
3233 -- such an attribute definition, and no pragma Pack.
3236 or else
3237 SSO_ADC_Component
3238 or else
3240 then
3241 Error_Msg_N
3243 SSO_ADC);
3247 -- Deal with Bit_Order aspect
3255 then
3256 -- Warn if clause has no effect when no component clause is
3257 -- present, but suppress warning if the Bit_Order is required
3258 -- due to the presence of a Scalar_Storage_Order attribute.
3260 Error_Msg_N
3262 Error_Msg_N
3265 -- Here is where we do the processing to adjust component clauses
3266 -- for reversed bit order.
3270 then
3273 -- Case where we have both an explicit Bit_Order and the same
3274 -- Scalar_Storage_Order: leave record untouched, the back-end
3275 -- will take care of required layout conversions.
3277 else
3283 -- Complete error checking on record representation clause (e.g.
3284 -- overlap of components). This is called after adjusting the
3285 -- record for reverse bit order.
3287 declare
3289 begin
3295 -- Set OK_To_Reorder_Components depending on debug flags
3299 or else
3301 then
3306 -- Check for useless pragma Pack when all components placed. We only
3307 -- do this check for record types, not subtypes, since a subtype may
3308 -- have all its components placed, and it still makes perfectly good
3309 -- sense to pack other subtypes or the parent type. We do not give
3310 -- this warning if Optimize_Alignment is set to Space, since the
3311 -- pragma Pack does have an effect in this case (it always resets
3312 -- the alignment to one).
3316 and then not Unplaced_Component
3318 then
3319 -- Reset packed status. Probably not necessary, but we do it so
3320 -- that there is no chance of the back end doing something strange
3321 -- with this redundant indication of packing.
3325 -- Give warning if redundant constructs warnings on
3328 Error_Msg_N -- CODEFIX
3334 -- If this is the record corresponding to a remote type, freeze the
3335 -- remote type here since that is what we are semantically freezing.
3336 -- This prevents the freeze node for that type in an inner scope.
3343 -- Check for controlled components and unchecked unions.
3348 -- Do not set Has_Controlled_Component on a class-wide
3349 -- equivalent type. See Make_CW_Equivalent_Type.
3352 and then
3354 or else
3357 or else
3359 and then
3361 and then
3362 Has_Controlled_Component
3364 then
3372 -- Scan component declaration for likely misuses of current
3373 -- instance, either in a constraint or a default expression.
3383 -- Enforce the restriction that access attributes with a current
3384 -- instance prefix can only apply to limited types. This comment
3385 -- is floating here, but does not seem to belong here???
3387 -- Set component alignment if not otherwise already set
3391 -- For first subtypes, check if there are any fixed-point fields with
3392 -- component clauses, where we must check the size. This is not done
3393 -- till the freeze point since for fixed-point types, we do not know
3394 -- the size until the type is frozen. Similar processing applies to
3395 -- bit packed arrays.
3403 then
3404 Check_Size
3408 Junk);
3415 -- Generate warning for applying C or C++ convention to a record
3416 -- with discriminants. This is suppressed for the unchecked union
3417 -- case, since the whole point in this case is interface C. We also
3418 -- do not generate this within instantiations, since we will have
3419 -- generated a message on the template.
3424 or else
3427 and then not In_Instance
3430 then
3431 declare
3435 begin
3440 Error_Msg_N
3442 A2);
3443 else
3444 Error_Msg_N
3446 A2);
3449 Error_Msg_NE
3455 -- See if Size is too small as is (and implicit packing might help)
3459 -- No implicit packing if even one component is explicitly placed
3461 and then not Placed_Component
3463 -- Or even one component is aliased
3465 and then not Aliased_Component
3467 -- Must have size clause and all scalar components
3470 and then All_Scalar_Components
3472 -- Do not try implicit packing on records with discriminants, too
3473 -- complicated, especially in the variant record case.
3477 -- We can implicitly pack if the specified size of the record is
3478 -- less than the sum of the object sizes (no point in packing if
3479 -- this is not the case).
3483 -- And the total RM size cannot be greater than the specified size
3484 -- since otherwise packing will not get us where we have to be.
3488 -- Never do implicit packing in CodePeer or SPARK modes since
3489 -- we don't do any packing in these modes, since this generates
3490 -- over-complex code that confuses static analysis, and in
3491 -- general, neither CodePeer not GNATprove care about the
3492 -- internal representation of objects.
3495 then
3496 -- If implicit packing enabled, do it
3501 -- Otherwise flag the size clause
3503 else
3504 declare
3506 begin
3507 Error_Msg_NE -- CODEFIX
3509 Error_Msg_N -- CODEFIX
3516 -- The following checks are only relevant when SPARK_Mode is on as
3517 -- they are not standard Ada legality rules.
3522 -- A discriminated type cannot be effectively volatile
3523 -- (SPARK RM C.6(4)).
3528 -- A tagged type cannot be effectively volatile
3529 -- (SPARK RM C.6(5)).
3535 -- A non-effectively volatile record type cannot contain
3536 -- effectively volatile components (SPARK RM C.6(2)).
3538 else
3543 then
3545 Error_Msg_N
3555 -- All done if not a full record definition
3561 -- Finally we need to check the variant part to make sure that
3562 -- all types within choices are properly frozen as part of the
3563 -- freezing of the record type.
3570 begin
3571 -- Find component list
3583 then
3588 -- Case of variant part present
3594 -- Note: we used to call Check_Choices here, but it is too early,
3595 -- since predicated subtypes are frozen here, but their freezing
3596 -- actions are in Analyze_Freeze_Entity, which has not been called
3597 -- yet for entities frozen within this procedure, so we moved that
3598 -- call to the Analyze_Freeze_Entity for the record type.
3603 -------------------------------
3604 -- Has_Boolean_Aspect_Import --
3605 -------------------------------
3612 begin
3618 -- The value of aspect Import is True when the expression is
3619 -- either missing or it is explicitly set to True.
3625 then
3636 ------------------------------
3637 -- Wrap_Imported_Subprogram --
3638 ------------------------------
3640 -- The issue here is that our normal approach of checking preconditions
3641 -- and postconditions does not work for imported procedures, since we
3642 -- are not generating code for the body. To get around this we create
3643 -- a wrapper, as shown by the following example:
3645 -- procedure K (A : Integer);
3646 -- pragma Import (C, K);
3648 -- The spec is rewritten by removing the effects of pragma Import, but
3649 -- leaving the convention unchanged, as though the source had said:
3651 -- procedure K (A : Integer);
3652 -- pragma Convention (C, K);
3654 -- and we create a body, added to the entity K freeze actions, which
3655 -- looks like:
3657 -- procedure K (A : Integer) is
3658 -- procedure K (A : Integer);
3659 -- pragma Import (C, K);
3660 -- begin
3661 -- K (A);
3662 -- end K;
3664 -- Now the contract applies in the normal way to the outer procedure,
3665 -- and the inner procedure has no contracts, so there is no problem
3666 -- in just calling it to get the original effect.
3668 -- In the case of a function, we create an appropriate return statement
3669 -- for the subprogram body that calls the inner procedure.
3681 begin
3682 -- Nothing to do if not imported
3687 -- Test enabling conditions for wrapping
3692 and then not GNATprove_Mode
3693 then
3694 -- Here we do the wrap
3696 -- Note on calls to Copy_Separate_Tree. The trees we are copying
3697 -- here are fully analyzed, but we definitely want fully syntactic
3698 -- unanalyzed trees in the body we construct, so that the analysis
3699 -- generates the right visibility, and that is exactly what the
3700 -- calls to Copy_Separate_Tree give us.
3702 -- Acquire copy of Inline pragma
3706 -- Fix up spec to be not imported any more
3713 -- Grab the subprogram declaration and specification
3717 -- Build parameter list that we need
3726 -- Build the call
3729 Stmt :=
3731 Expression =>
3736 else
3737 Stmt :=
3743 -- Now build the body
3745 Bod :=
3747 Specification =>
3751 Specification =>
3753 Iprag),
3754 Handled_Statement_Sequence =>
3759 -- Append the body to freeze result
3764 -- Case of imported subprogram that does not get wrapped
3766 else
3767 -- Set Is_Public. All imported entities need an external symbol
3768 -- created for them since they are always referenced from another
3769 -- object file. Note this used to be set when we set Is_Imported
3770 -- back in Sem_Prag, but now we delay it to this point, since we
3771 -- don't want to set this flag if we wrap an imported subprogram.
3777 -- Start of processing for Freeze_Entity
3779 begin
3780 -- We are going to test for various reasons why this entity need not be
3781 -- frozen here, but in the case of an Itype that's defined within a
3782 -- record, that test actually applies to the record.
3788 then
3792 -- Do not freeze if already frozen since we only need one freeze node
3797 -- It is improper to freeze an external entity within a generic because
3798 -- its freeze node will appear in a non-valid context. The entity will
3799 -- be frozen in the proper scope after the current generic is analyzed.
3800 -- However, aspects must be analyzed because they may be queried later
3801 -- within the generic itself, and the corresponding pragma or attribute
3802 -- definition has not been analyzed yet.
3811 -- AI05-0213: A formal incomplete type does not freeze the actual. In
3812 -- the instance, the same applies to the subtype renaming the actual.
3818 then
3821 -- Generic types need no freeze node and have no delayed semantic
3822 -- checks.
3827 -- Do not freeze a global entity within an inner scope created during
3828 -- expansion. A call to subprogram E within some internal procedure
3829 -- (a stream attribute for example) might require freezing E, but the
3830 -- freeze node must appear in the same declarative part as E itself.
3831 -- The two-pass elaboration mechanism in gigi guarantees that E will
3832 -- be frozen before the inner call is elaborated. We exclude constants
3833 -- from this test, because deferred constants may be frozen early, and
3834 -- must be diagnosed (e.g. in the case of a deferred constant being used
3835 -- in a default expression). If the enclosing subprogram comes from
3836 -- source, or is a generic instance, then the freeze point is the one
3837 -- mandated by the language, and we freeze the entity. A subprogram that
3838 -- is a child unit body that acts as a spec does not have a spec that
3839 -- comes from source, but can only come from source.
3844 then
3845 declare
3848 begin
3855 then
3857 else
3866 -- Similarly, an inlined instance body may make reference to global
3867 -- entities, but these references cannot be the proper freezing point
3868 -- for them, and in the absence of inlining freezing will take place in
3869 -- their own scope. Normally instance bodies are analyzed after the
3870 -- enclosing compilation, and everything has been frozen at the proper
3871 -- place, but with front-end inlining an instance body is compiled
3872 -- before the end of the enclosing scope, and as a result out-of-order
3873 -- freezing must be prevented.
3875 elsif Front_End_Inlining
3876 and then In_Instance_Body
3878 then
3879 declare
3882 begin
3887 else
3901 -- Add checks to detect proper initialization of scalars that may appear
3902 -- as subprogram parameters.
3908 -- Deal with delayed aspect specifications. The analysis of the aspect
3909 -- is required to be delayed to the freeze point, thus we analyze the
3910 -- pragma or attribute definition clause in the tree at this point. We
3911 -- also analyze the aspect specification node at the freeze point when
3912 -- the aspect doesn't correspond to pragma/attribute definition clause.
3918 -- Here to freeze the entity
3922 -- Case of entity being frozen is other than a type
3926 -- If entity is exported or imported and does not have an external
3927 -- name, now is the time to provide the appropriate default name.
3928 -- Skip this if the entity is stubbed, since we don't need a name
3929 -- for any stubbed routine. For the case on intrinsics, if no
3930 -- external name is specified, then calls will be handled in
3931 -- Exp_Intr.Expand_Intrinsic_Call, and no name is needed. If an
3932 -- external name is provided, then Expand_Intrinsic_Call leaves
3933 -- calls in place for expansion by GIGI.
3939 then
3940 Set_Encoded_Interface_Name
3943 -- If entity is an atomic object appearing in a declaration and
3944 -- the expression is an aggregate, assign it to a temporary to
3945 -- ensure that the actual assignment is done atomically rather
3946 -- than component-wise (the assignment to the temp may be done
3947 -- component-wise, but that is harmless).
3954 then
3958 -- Subprogram case
3962 -- Check for needing to wrap imported subprogram
3966 -- Freeze all parameter types and the return type (RM 13.14(14)).
3967 -- However skip this for internal subprograms. This is also where
3968 -- any extra formal parameters are created since we now know
3969 -- whether the subprogram will use a foreign convention.
3972 declare
3977 begin
3978 -- Loop through formals
3984 -- AI05-0151 : incomplete types can appear in a profile.
3985 -- By the time the entity is frozen, the full view must
3986 -- be available, unless it is a limited view.
3991 then
4003 then
4004 -- If the type of a formal is incomplete, subprogram
4005 -- is being frozen prematurely. Within an instance
4006 -- (but not within a wrapper package) this is an
4007 -- artifact of our need to regard the end of an
4008 -- instantiation as a freeze point. Otherwise it is
4009 -- a definite error.
4015 elsif not After_Last_Declaration
4016 and then not Freezing_Library_Level_Tagged_Type
4017 then
4019 Error_Msg
4021 Loc);
4025 -- Check suspicious parameter for C function. These tests
4026 -- apply only to exported/imported subprograms.
4028 if Warn_On_Export_Import
4031 or else
4038 then
4039 -- Qualify mention of formals with subprogram name
4043 -- Check suspicious use of fat C pointer
4047 then
4048 Error_Msg_N
4050 Formal);
4052 -- Check suspicious return of boolean
4059 then
4060 Error_Msg_N
4062 Error_Msg_N
4066 -- Check suspicious tagged type
4070 and then
4071 Is_Tagged_Type
4074 then
4075 Error_Msg_N
4079 -- Check wrong convention subprogram pointer
4083 then
4084 Error_Msg_N
4088 Error_Msg_NE
4093 -- Turn off name qualification after message output
4098 -- Check for unconstrained array in exported foreign
4099 -- convention case.
4105 and then Warn_On_Export_Import
4107 -- Exclude VM case, since both .NET and JVM can handle
4108 -- unconstrained arrays without a problem.
4111 then
4114 -- If this is an inherited operation, place the
4115 -- warning on the derived type declaration, rather
4116 -- than on the original subprogram.
4119 N_Full_Type_Declaration
4120 then
4124 Error_Msg_NE
4127 else
4131 Error_Msg_NE
4134 Error_Msg_NE
4145 -- If the formal is an anonymous_access_to_subprogram
4146 -- freeze the subprogram type as well, to prevent
4147 -- scope anomalies in gigi, because there is no other
4148 -- clear point at which it could be frozen.
4152 then
4160 -- Case of function: similar checks on return type
4164 -- Freeze return type
4168 -- AI05-0151: the return type may have been incomplete
4169 -- at the point of declaration. Replace it with the full
4170 -- view, unless the current type is a limited view. In
4171 -- that case the full view is in a different unit, and
4172 -- gigi finds the non-limited view after the other unit
4173 -- is elaborated.
4178 then
4182 -- If the return type is a limited view and the non-
4183 -- limited view is still incomplete, the function has
4184 -- to be frozen at a later time.
4188 and then
4190 then
4197 -- Check suspicious return type for C function
4199 if Warn_On_Export_Import
4201 or else
4204 then
4205 -- Check suspicious return of fat C pointer
4211 then
4212 Error_Msg_N
4216 -- Check suspicious return of boolean
4224 then
4225 declare
4228 begin
4229 Error_Msg_NE
4232 Error_Msg_NE
4237 -- Check suspicious return tagged type
4241 and then
4242 Is_Tagged_Type
4247 then
4248 Error_Msg_N
4252 -- Check return of wrong convention subprogram pointer
4258 then
4259 Error_Msg_N
4263 Error_Msg_NE
4269 -- Give warning for suspicious return of a result of an
4270 -- unconstrained array type in a foreign convention
4271 -- function.
4275 -- We are looking for a return of unconstrained array
4280 -- Exclude imported routines, the warning does not
4281 -- belong on the import, but rather on the routine
4282 -- definition.
4286 -- Exclude VM case, since both .NET and JVM can handle
4287 -- return of unconstrained arrays without a problem.
4291 -- Check that general warning is enabled, and that it
4292 -- is not suppressed for this particular case.
4294 and then Warn_On_Export_Import
4297 then
4298 Error_Msg_N
4306 -- Must freeze its parent first if it is a derived subprogram
4312 -- We don't freeze internal subprograms, because we don't normally
4313 -- want addition of extra formals or mechanism setting to happen
4314 -- for those. However we do pass through predefined dispatching
4315 -- cases, since extra formals may be needed in some cases, such as
4316 -- for the stream 'Input function (build-in-place formals).
4320 then
4324 -- If warning on suspicious contracts then check for the case of
4325 -- a postcondition other than False for a No_Return subprogram.
4328 and then Warn_On_Suspicious_Contract
4330 then
4331 declare
4335 begin
4338 Name_Postcondition,
4339 Name_Refined_Post)
4340 then
4341 Exp :=
4342 Expression
4347 then
4348 Error_Msg_NE
4359 -- Here for other than a subprogram or type
4361 else
4362 -- If entity has a type, and it is not a generic unit, then
4363 -- freeze it first (RM 13.14(10)).
4367 then
4371 -- Special processing for objects created by object declaration
4375 -- Abstract type allowed only for C++ imported variables or
4376 -- constants.
4378 -- Note: we inhibit this check for objects that do not come
4379 -- from source because there is at least one case (the
4380 -- expansion of x'Class'Input where x is abstract) where we
4381 -- legitimately generate an abstract object.
4387 then
4392 Error_Msg_NE
4398 -- For object created by object declaration, perform required
4399 -- categorization (preelaborate and pure) checks. Defer these
4400 -- checks to freeze time since pragma Import inhibits default
4401 -- initialization and thus pragma Import affects these checks.
4405 -- If there is an address clause, check that it is valid
4409 -- Reset Is_True_Constant for aliased object. We consider that
4410 -- the fact that something is aliased may indicate that some
4411 -- funny business is going on, e.g. an aliased object is passed
4412 -- by reference to a procedure which captures the address of
4413 -- the object, which is later used to assign a new value. Such
4414 -- code is highly dubious, but we choose to make it "work" for
4415 -- aliased objects.
4417 -- However, we don't do that for internal entities. We figure
4418 -- that if we deliberately set Is_True_Constant for an internal
4419 -- entity, e.g. a dispatch table entry, then we mean it.
4423 then
4427 -- If the object needs any kind of default initialization, an
4428 -- error must be issued if No_Default_Initialization applies.
4429 -- The check doesn't apply to imported objects, which are not
4430 -- ever default initialized, and is why the check is deferred
4431 -- until freezing, at which point we know if Import applies.
4432 -- Deferred constants are also exempted from this test because
4433 -- their completion is explicit, or through an import pragma.
4437 then
4443 and then
4448 or else
4451 then
4453 Check_Restriction
4457 -- Check that a Thread_Local_Storage variable does not have
4458 -- default initialization, and any explicit initialization must
4459 -- either be the null constant or a static constant.
4462 declare
4464 begin
4465 if Has_Default_Initialization
4466 or else
4468 and then
4470 or else not
4472 or else
4474 then
4475 Error_Msg_NE
4478 Error_Msg_NE
4485 -- For imported objects, set Is_Public unless there is also an
4486 -- address clause, which means that there is no external symbol
4487 -- needed for the Import (Is_Public may still be set for other
4488 -- unrelated reasons). Note that we delayed this processing
4489 -- till freeze time so that we can be sure not to set the flag
4490 -- if there is an address clause. If there is such a clause,
4491 -- then the only purpose of the Import pragma is to suppress
4492 -- implicit initialization.
4498 -- For source objects that are not Imported and are library
4499 -- level, if no linker section pragma was given inherit the
4500 -- appropriate linker section from the corresponding type.
4506 then
4507 Set_Linker_Section_Pragma
4511 -- For convention C objects of an enumeration type, warn if
4512 -- the size is not integer size and no explicit size given.
4513 -- Skip warning for Boolean, and Character, assume programmer
4514 -- expects 8-bit sizes for these cases.
4517 or else
4524 then
4526 Error_Msg_N
4528 E);
4533 -- Check that a constant which has a pragma Volatile[_Components]
4534 -- or Atomic[_Components] also has a pragma Import (RM C.6(13)).
4536 -- Note: Atomic[_Components] also sets Volatile[_Components]
4542 then
4543 -- Make sure we actually have a pragma, and have not merely
4544 -- inherited the indication from elsewhere (e.g. an address
4545 -- clause, which is not good enough in RM terms).
4548 or else
4550 then
4551 Error_Msg_N
4556 or else
4558 then
4559 Error_Msg_N
4565 -- Static objects require special handling
4569 then
4573 -- Remaining step is to layout objects
4577 then
4581 -- For an object that does not have delayed freezing, and whose
4582 -- initialization actions have been captured in a compound
4583 -- statement, move them back now directly within the enclosing
4584 -- statement sequence.
4588 then
4593 -- Case of a type or subtype being frozen
4595 else
4596 -- We used to check here that a full type must have preelaborable
4597 -- initialization if it completes a private type specified with
4598 -- pragma Preelaborable_Initialization, but that missed cases where
4599 -- the types occur within a generic package, since the freezing
4600 -- that occurs within a containing scope generally skips traversal
4601 -- of a generic unit's declarations (those will be frozen within
4602 -- instances). This check was moved to Analyze_Package_Specification.
4604 -- The type may be defined in a generic unit. This can occur when
4605 -- freezing a generic function that returns the type (which is
4606 -- defined in a parent unit). It is clearly meaningless to freeze
4607 -- this type. However, if it is a subtype, its size may be determi-
4608 -- nable and used in subsequent checks, so might as well try to
4609 -- compute it.
4611 -- In Ada 2012, Freeze_Entities is also used in the front end to
4612 -- trigger the analysis of aspect expressions, so in this case we
4613 -- want to continue the freezing process.
4617 and then
4620 then
4625 -- Check for error of Type_Invariant'Class applied to an untagged
4626 -- type (check delayed to freeze time when full type is available).
4628 declare
4630 begin
4634 then
4635 Error_Msg_NE
4638 Error_Msg_N
4643 -- Deal with special cases of freezing for subtype
4647 -- Before we do anything else, a specialized test for the case of
4648 -- a size given for an array where the array needs to be packed,
4649 -- but was not so the size cannot be honored. This is the case
4650 -- where implicit packing may apply. The reason we do this so
4651 -- early is that if we have implicit packing, the layout of the
4652 -- base type is affected, so we must do this before we freeze
4653 -- the base type.
4655 -- We could do this processing only if implicit packing is enabled
4656 -- since in all other cases, the error would be caught by the back
4657 -- end. However, we choose to do the check even if we do not have
4658 -- implicit packing enabled, since this allows us to give a more
4659 -- useful error message (advising use of pragmas Implicit_Packing
4660 -- or Pack).
4663 declare
4674 -- Number of elements in array
4676 begin
4677 -- Check enabling conditions. These are straightforward
4678 -- except for the test for a limited composite type. This
4679 -- eliminates the rare case of a array of limited components
4680 -- where there are issues of whether or not we can go ahead
4681 -- and pack the array (since we can't freely pack and unpack
4682 -- arrays if they are limited).
4684 -- Note that we check the root type explicitly because the
4685 -- whole point is we are doing this test before we have had
4686 -- a chance to freeze the base type (and it is that freeze
4687 -- action that causes stuff to be inherited).
4700 then
4701 -- Compute number of elements in array
4709 and then
4711 then
4715 Num_Elmts :=
4716 Num_Elmts *
4722 -- What we are looking for here is the situation where
4723 -- the RM_Size given would be exactly right if there was
4724 -- a pragma Pack (resulting in the component size being
4725 -- the same as the RM_Size). Furthermore, the component
4726 -- type size must be an odd size (not a multiple of
4727 -- storage unit). If the component RM size is an exact
4728 -- number of storage units that is a power of two, the
4729 -- array is not packed and has a standard representation.
4733 then
4734 -- For implicit packing mode, just set the component
4735 -- size silently.
4743 -- Otherwise give an error message
4745 else
4746 Error_Msg_NE
4748 Error_Msg_N -- CODEFIX
4754 and then Implicit_Packing
4755 and then
4757 or else
4759 or else
4761 then
4762 -- Not a packed array, but indicate the desired
4763 -- component size, for the back-end.
4773 -- If ancestor subtype present, freeze that first. Note that this
4774 -- will also get the base type frozen. Need RM reference ???
4781 -- No ancestor subtype present
4783 else
4784 -- See if we have a nearest ancestor that has a predicate.
4785 -- That catches the case of derived type with a predicate.
4786 -- Need RM reference here ???
4794 -- Freeze base type before freezing the entity (RM 13.14(15))
4801 -- A subtype inherits all the type-related representation aspects
4802 -- from its parents (RM 13.1(8)).
4806 -- For a derived type, freeze its parent type first (RM 13.14(15))
4812 -- A derived type inherits each type-related representation aspect
4813 -- of its parent type that was directly specified before the
4814 -- declaration of the derived type (RM 13.1(15)).
4819 -- Check for incompatible size and alignment for record type
4821 if Warn_On_Size_Alignment
4825 -- If explicit Object_Size clause given assume that the programmer
4826 -- knows what he is doing, and expects the compiler behavior.
4830 -- Check for size not a multiple of alignment
4833 then
4834 declare
4840 begin
4843 -- Give a warning
4847 Error_Msg_NE
4853 else
4855 Error_Msg_NE
4868 -- Array type
4873 -- For a class-wide type, the corresponding specific type is
4874 -- frozen as well (RM 13.14(15))
4879 -- If the base type of the class-wide type is still incomplete,
4880 -- the class-wide remains unfrozen as well. This is legal when
4881 -- E is the formal of a primitive operation of some other type
4882 -- which is being frozen.
4889 -- The equivalent type associated with a class-wide subtype needs
4890 -- to be frozen to ensure that its layout is done.
4894 then
4898 -- Generate an itype reference for a library-level class-wide type
4899 -- at the freeze point. Otherwise the first explicit reference to
4900 -- the type may appear in an inner scope which will be rejected by
4901 -- the back-end.
4905 then
4906 declare
4909 begin
4912 -- From a gigi point of view, a class-wide subtype derives
4913 -- from its record equivalent type. As a result, the itype
4914 -- reference must appear after the freeze node of the
4915 -- equivalent type or gigi will reject the reference.
4919 then
4921 else
4927 -- For a record type or record subtype, freeze all component types
4928 -- (RM 13.14(15)). We test for E_Record_(sub)Type here, rather than
4929 -- using Is_Record_Type, because we don't want to attempt the freeze
4930 -- for the case of a private type with record extension (we will do
4931 -- that later when the full type is frozen).
4935 then
4938 -- For a concurrent type, freeze corresponding record type. This does
4939 -- not correspond to any specific rule in the RM, but the record type
4940 -- is essentially part of the concurrent type. Also freeze all local
4941 -- entities. This includes record types created for entry parameter
4942 -- blocks and whatever local entities may appear in the private part.
4956 -- The guard on the presence of the Etype seems to be needed
4957 -- for some CodePeer (-gnatcC) cases, but not clear why???
4962 then
4973 -- Private types are required to point to the same freeze node as
4974 -- their corresponding full views. The freeze node itself has to
4975 -- point to the partial view of the entity (because from the partial
4976 -- view, we can retrieve the full view, but not the reverse).
4977 -- However, in order to freeze correctly, we need to freeze the full
4978 -- view. If we are freezing at the end of a scope (or within the
4979 -- scope) of the private type, the partial and full views will have
4980 -- been swapped, the full view appears first in the entity chain and
4981 -- the swapping mechanism ensures that the pointers are properly set
4982 -- (on scope exit).
4984 -- If we encounter the partial view before the full view (e.g. when
4985 -- freezing from another scope), we freeze the full view, and then
4986 -- set the pointers appropriately since we cannot rely on swapping to
4987 -- fix things up (subtypes in an outer scope might not get swapped).
4989 -- If the full view is itself private, the above requirements apply
4990 -- to the underlying full view instead of the full view. But there is
4991 -- no swapping mechanism for the underlying full view so we need to
4992 -- set the pointers appropriately in both cases.
4996 then
4997 -- The construction of the dispatch table associated with library
4998 -- level tagged types forces freezing of all the primitives of the
4999 -- type, which may cause premature freezing of the partial view.
5000 -- For example:
5002 -- package Pkg is
5003 -- type T is tagged private;
5004 -- type DT is new T with private;
5005 -- procedure Prim (X : in out T; Y : in out DT'Class);
5006 -- private
5007 -- type T is tagged null record;
5008 -- Obj : T;
5009 -- type DT is new T with null record;
5010 -- end;
5012 -- In this case the type will be frozen later by the usual
5013 -- mechanism: an object declaration, an instantiation, or the
5014 -- end of a declarative part.
5018 then
5022 -- Case of full view present
5026 -- If full view has already been frozen, then no further
5027 -- processing is required
5033 -- Otherwise freeze full view and patch the pointers so that
5034 -- the freeze node will elaborate both views in the back end.
5035 -- However, if full view is itself private, freeze underlying
5036 -- full view instead and patch the pointers so that the freeze
5037 -- node will elaborate the three views in the back end.
5039 else
5040 declare
5043 begin
5046 then
5054 then
5061 else
5074 else
5075 -- {Incomplete,Private}_Subtypes with Full_Views
5076 -- constrained by discriminants.
5087 -- AI-117 requires that the convention of a partial view be the
5088 -- same as the convention of the full view. Note that this is a
5089 -- recognized breach of privacy, but it's essential for logical
5090 -- consistency of representation, and the lack of a rule in
5091 -- RM95 was an oversight.
5098 -- Size information is copied from the full view to the
5099 -- incomplete or private view for consistency.
5101 -- We skip this is the full view is not a type. This is very
5102 -- strange of course, and can only happen as a result of
5103 -- certain illegalities, such as a premature attempt to derive
5104 -- from an incomplete type.
5113 -- Case of underlying full view present
5117 then
5122 -- Patch the pointers so that the freeze node will elaborate
5123 -- both views in the back end.
5132 else
5142 -- Case of no full view present. If entity is derived or subtype,
5143 -- it is safe to freeze, correctness depends on the frozen status
5144 -- of parent. Otherwise it is either premature usage, or a Taft
5145 -- amendment type, so diagnosis is at the point of use and the
5146 -- type might be frozen later.
5151 else
5156 -- For access subprogram, freeze types of all formals, the return
5157 -- type was already frozen, since it is the Etype of the function.
5158 -- Formal types can be tagged Taft amendment types, but otherwise
5159 -- they cannot be incomplete.
5167 then
5171 -- AI05-151: Incomplete types are allowed in access to
5172 -- subprogram specifications.
5175 Error_Msg_NE
5186 -- For access to a protected subprogram, freeze the equivalent type
5187 -- (however this is not set if we are not generating code or if this
5188 -- is an anonymous type used just for resolution).
5196 -- Generic types are never seen by the back-end, and are also not
5197 -- processed by the expander (since the expander is turned off for
5198 -- generic processing), so we never need freeze nodes for them.
5204 -- Some special processing for non-generic types to complete
5205 -- representation details not known till the freeze point.
5210 -- Some error checks required for ordinary fixed-point type. Defer
5211 -- these till the freeze-point since we need the small and range
5212 -- values. We only do these checks for base types
5217 Error_Msg_N
5222 Error_Msg_N
5228 Error_Msg_N
5234 Error_Msg_N
5246 and then Warn_On_Suspicious_Modulus_Value
5247 then
5253 then
5254 -- If a pragma Default_Storage_Pool applies, and this type has no
5255 -- Storage_Pool or Storage_Size clause (which must have occurred
5256 -- before the freezing point), then use the default. This applies
5257 -- only to base types.
5259 -- None of this applies to access to subprograms, for which there
5260 -- are clearly no pools.
5266 then
5267 -- Case of pragma Default_Storage_Pool (null)
5272 -- Case of pragma Default_Storage_Pool (storage_pool_NAME)
5274 else
5279 -- Check restriction for standard storage pool
5285 -- Deal with error message for pure access type. This is not an
5286 -- error in Ada 2005 if there is no pool (see AI-366).
5292 then
5296 Error_Msg_N
5300 Error_Msg_N
5303 else
5304 Error_Msg_N
5311 -- Case of composite types
5315 -- AI-117 requires that all new primitives of a tagged type must
5316 -- inherit the convention of the full view of the type. Inherited
5317 -- and overriding operations are defined to inherit the convention
5318 -- of their parent or overridden subprogram (also specified in
5319 -- AI-117), which will have occurred earlier (in Derive_Subprogram
5320 -- and New_Overloaded_Entity). Here we set the convention of
5321 -- primitives that are still convention Ada, which will ensure
5322 -- that any new primitives inherit the type's convention. Class-
5323 -- wide types can have a foreign convention inherited from their
5324 -- specific type, but are excluded from this since they don't have
5325 -- any associated primitives.
5330 then
5331 declare
5335 begin
5347 -- If the type is a simple storage pool type, then this is where
5348 -- we attempt to locate and validate its Allocate, Deallocate, and
5349 -- Storage_Size operations (the first is required, and the latter
5350 -- two are optional). We also verify that the full type for a
5351 -- private type is allowed to be a simple storage pool type.
5355 then
5356 -- If the type is marked Has_Private_Declaration, then this is
5357 -- a full type for a private type that was specified with the
5358 -- pragma Simple_Storage_Pool_Type, and here we ensure that the
5359 -- pragma is allowed for the full type (for example, it can't
5360 -- be an array type, or a nonlimited record type).
5365 then
5367 Error_Msg_N
5378 procedure Validate_Simple_Pool_Op_Formal
5385 -- Validate one formal Pool_Op_Formal of the candidate pool
5386 -- operation Pool_Op. The formal must be of Expected_Type
5387 -- and have mode Expected_Mode. OK_Formal will be set to
5388 -- False if the formal doesn't match. If OK_Formal is False
5389 -- on entry, then the formal will effectively be ignored
5390 -- (because validation of the pool op has already failed).
5391 -- Upon return, Pool_Op_Formal will be updated to the next
5392 -- formal, if any.
5394 procedure Validate_Simple_Pool_Operation
5396 -- Search for and validate a simple pool operation with the
5397 -- name Op_Name. If the name is Allocate, then there must be
5398 -- exactly one such primitive operation for the simple pool
5399 -- type. If the name is Deallocate or Storage_Size, then
5400 -- there can be at most one such primitive operation. The
5401 -- profile of the located primitive must conform to what
5402 -- is expected for each operation.
5404 ------------------------------------
5405 -- Validate_Simple_Pool_Op_Formal --
5406 ------------------------------------
5408 procedure Validate_Simple_Pool_Op_Formal
5415 is
5416 begin
5417 -- If OK_Formal is False on entry, then simply ignore
5418 -- the formal, because an earlier formal has already
5419 -- been flagged.
5424 -- If no formal is passed in, then issue an error for a
5425 -- missing formal.
5428 Error_Msg_NE
5438 -- If the pool type was expected for this formal, then
5439 -- this will not be considered a candidate operation
5440 -- for the simple pool, so we unset OK_Formal so that
5441 -- the op and any later formals will be ignored.
5448 else
5449 Error_Msg_NE
5456 -- Issue error if formal's mode is not the expected one
5459 Error_Msg_N
5461 Pool_Op_Formal);
5464 -- Advance to the next formal
5469 ------------------------------------
5470 -- Validate_Simple_Pool_Operation --
5471 ------------------------------------
5473 procedure Validate_Simple_Pool_Operation
5475 is
5481 begin
5482 pragma Assert
5484 Name_Deallocate,
5485 Name_Storage_Size));
5489 -- For each homonym declared immediately in the scope
5490 -- of the simple storage pool type, determine whether
5491 -- the homonym is an operation of the pool type, and,
5492 -- if so, check that its profile is as expected for
5493 -- a simple pool operation of that name.
5499 then
5504 -- The first parameter must be of the pool type
5505 -- in order for the operation to qualify.
5508 Validate_Simple_Pool_Op_Formal
5511 else
5512 Validate_Simple_Pool_Op_Formal
5517 -- If another operation with this name has already
5518 -- been located for the type, then flag an error,
5519 -- since we only allow the type to have a single
5520 -- such primitive.
5523 Error_Msg_NE
5528 -- In the case of Allocate and Deallocate, a formal
5529 -- of type System.Address is required.
5532 Validate_Simple_Pool_Op_Formal
5537 Validate_Simple_Pool_Op_Formal
5542 -- In the case of Allocate and Deallocate, formals
5543 -- of type Storage_Count are required as the third
5544 -- and fourth parameters.
5547 Validate_Simple_Pool_Op_Formal
5550 Validate_Simple_Pool_Op_Formal
5555 -- If no mismatched formals have been found (Is_OK)
5556 -- and no excess formals are present, then this
5557 -- operation has been validated, so record it.
5567 -- There must be a valid Allocate operation for the type,
5568 -- so issue an error if none was found.
5572 then
5578 -- Simple pool operations can't be abstract
5581 Error_Msg_N
5586 -- The Storage_Size operation must be a function with
5587 -- Storage_Count as its result type.
5591 Error_Msg_N
5595 Error_Msg_NE
5600 -- Allocate and Deallocate must be procedures
5603 Error_Msg_N
5609 -- Start of processing for Validate_Simple_Pool_Ops
5611 begin
5619 -- Now that all types from which E may depend are frozen, see if the
5620 -- size is known at compile time, if it must be unsigned, or if
5621 -- strict alignment is required
5630 -- Do not allow a size clause for a type which does not have a size
5631 -- that is known at compile time
5635 then
5636 -- Suppress this message if errors posted on E, even if we are
5637 -- in all errors mode, since this is often a junk message
5640 Error_Msg_N
5646 -- Now we set/verify the representation information, in particular
5647 -- the size and alignment values. This processing is not required for
5648 -- generic types, since generic types do not play any part in code
5649 -- generation, and so the size and alignment values for such types
5650 -- are irrelevant. Ditto for types declared within a generic unit,
5651 -- which may have components that depend on generic parameters, and
5652 -- that will be recreated in an instance.
5657 -- Otherwise we call the layout procedure
5659 else
5663 -- If this is an access to subprogram whose designated type is itself
5664 -- a subprogram type, the return type of this anonymous subprogram
5665 -- type must be decorated as well.
5669 then
5673 -- If the type has a Defaut_Value/Default_Component_Value aspect,
5674 -- this is where we analye the expression (after the type is frozen,
5675 -- since in the case of Default_Value, we are analyzing with the
5676 -- type itself, and we treat Default_Component_Value similarly for
5677 -- the sake of uniformity).
5680 declare
5685 begin
5690 else
5701 Flag_Non_Static_Expr
5708 -- End of freeze processing for type entities
5711 -- Here is where we logically freeze the current entity. If it has a
5712 -- freeze node, then this is the point at which the freeze node is
5713 -- linked into the result list.
5717 -- If a freeze node is already allocated, use it, otherwise allocate
5718 -- a new one. The preallocation happens in the case of anonymous base
5719 -- types, where we preallocate so that we can set First_Subtype_Link.
5720 -- Note that we reset the Sloc to the current freeze location.
5726 else
5737 -- A final pass over record types with discriminants. If the type
5738 -- has an incomplete declaration, there may be constrained access
5739 -- subtypes declared elsewhere, which do not depend on the discrimi-
5740 -- nants of the type, and which are used as component types (i.e.
5741 -- the full view is a recursive type). The designated types of these
5742 -- subtypes can only be elaborated after the type itself, and they
5743 -- need an itype reference.
5747 then
5748 declare
5753 begin
5763 then
5775 -- When a type is frozen, the first subtype of the type is frozen as
5776 -- well (RM 13.14(15)). This has to be done after freezing the type,
5777 -- since obviously the first subtype depends on its own base type.
5782 -- If we just froze a tagged non-class wide record, then freeze the
5783 -- corresponding class-wide type. This must be done after the tagged
5784 -- type itself is frozen, because the class-wide type refers to the
5785 -- tagged type which generates the class.
5790 then
5797 -- Special handling for subprograms
5801 -- If subprogram has address clause then reset Is_Public flag, since
5802 -- we do not want the backend to generate external references.
5806 then
5814 -----------------------------
5815 -- Freeze_Enumeration_Type --
5816 -----------------------------
5819 begin
5820 -- By default, if no size clause is present, an enumeration type with
5821 -- Convention C is assumed to interface to a C enum, and has integer
5822 -- size. This applies to types. For subtypes, verify that its base
5823 -- type has no size clause either. Treat other foreign conventions
5824 -- in the same way, and also make sure alignment is set right.
5831 -- Don't do this if Short_Enums on target
5833 and then not Target_Short_Enums
5834 then
5838 -- Normal Ada case or size clause present or not Long_C_Enums on target
5840 else
5841 -- If the enumeration type interfaces to C, and it has a size clause
5842 -- that specifies less than int size, it warrants a warning. The
5843 -- user may intend the C type to be an enum or a char, so this is
5844 -- not by itself an error that the Ada compiler can detect, but it
5845 -- it is a worth a heads-up. For Boolean and Character types we
5846 -- assume that the programmer has the proper C type in mind.
5854 -- Don't do this if Short_Enums on target
5856 and then not Target_Short_Enums
5857 then
5858 Error_Msg_N
5866 -----------------------
5867 -- Freeze_Expression --
5868 -----------------------
5879 -- This flag is set true if the entity must be frozen outside the
5880 -- current subprogram. This happens in the case of expander generated
5881 -- subprograms (_Init_Proc, _Input, _Output, _Read, _Write) which do
5882 -- not freeze all entities like other bodies, but which nevertheless
5883 -- may reference entities that have to be frozen before the body and
5884 -- obviously cannot be frozen inside the body.
5887 -- Given an N_Handled_Sequence_Of_Statements node N, determines whether
5888 -- it is the handled statement sequence of an expander-generated
5889 -- subprogram (init proc, stream subprogram, or renaming as body).
5890 -- If so, this is not a freezing context.
5892 -----------------
5893 -- In_Exp_Body --
5894 -----------------
5900 begin
5903 else
5910 else
5913 -- Following complex conditional could use comments ???
5922 N_Subprogram_Renaming_Declaration,
5923 N_Expression_Function))
5924 then
5926 else
5932 -- Start of processing for Freeze_Expression
5934 begin
5935 -- Immediate return if freezing is inhibited. This flag is set by the
5936 -- analyzer to stop freezing on generated expressions that would cause
5937 -- freezing if they were in the source program, but which are not
5938 -- supposed to freeze, since they are created.
5944 -- If expression is non-static, then it does not freeze in a default
5945 -- expression, see section "Handling of Default Expressions" in the
5946 -- spec of package Sem for further details. Note that we have to make
5947 -- sure that we actually have a real expression (if we have a subtype
5948 -- indication, we can't test Is_OK_Static_Expression). However, we
5949 -- exclude the case of the prefix of an attribute of a static scalar
5950 -- subtype from this early return, because static subtype attributes
5951 -- should always cause freezing, even in default expressions, but
5952 -- the attribute may not have been marked as static yet (because in
5953 -- Resolve_Attribute, the call to Eval_Attribute follows the call of
5954 -- Freeze_Expression on the prefix).
5956 if In_Spec_Exp
5963 then
5967 -- Freeze type of expression if not frozen already
5975 -- Base type may be an derived numeric type that is frozen at
5976 -- the point of declaration, but first_subtype is still unfrozen.
5983 -- For entity name, freeze entity if not frozen already. A special
5984 -- exception occurs for an identifier that did not come from source.
5985 -- We don't let such identifiers freeze a non-internal entity, i.e.
5986 -- an entity that did come from source, since such an identifier was
5987 -- generated by the expander, and cannot have any semantic effect on
5988 -- the freezing semantics. For example, this stops the parameter of
5989 -- an initialization procedure from freezing the variable.
5996 then
6003 else
6007 -- For an allocator freeze designated type if not frozen already
6009 -- For an aggregate whose component type is an access type, freeze the
6010 -- designated type now, so that its freeze does not appear within the
6011 -- loop that might be created in the expansion of the aggregate. If the
6012 -- designated type is a private type without full view, the expression
6013 -- cannot contain an allocator, so the type is not frozen.
6015 -- For a function, we freeze the entity when the subprogram declaration
6016 -- is frozen, but a function call may appear in an initialization proc.
6017 -- before the declaration is frozen. We need to generate the extra
6018 -- formals, if any, to ensure that the expansion of the call includes
6019 -- the proper actuals. This only applies to Ada subprograms, not to
6020 -- imported ones.
6031 then
6035 when N_Selected_Component |
6036 N_Indexed_Component |
6037 N_Slice =>
6048 then
6059 then
6063 -- All done if nothing needs freezing
6068 then
6072 -- Examine the enclosing context by climbing the parent chain. The
6073 -- traversal serves two purposes - to detect scenarios where freezeing
6074 -- is not needed and to find the proper insertion point for the freeze
6075 -- nodes. Although somewhat similar to Insert_Actions, this traversal
6076 -- is freezing semantics-sensitive. Inserting freeze nodes blindly in
6077 -- the tree may result in types being frozen too early.
6080 loop
6083 -- If we don't have a parent, then we are not in a well-formed tree.
6084 -- This is an unusual case, but there are some legitimate situations
6085 -- in which this occurs, notably when the expressions in the range of
6086 -- a type declaration are resolved. We simply ignore the freeze
6087 -- request in this case. Is this right ???
6093 -- See if we have got to an appropriate point in the tree
6097 -- A special test for the exception of (RM 13.14(8)) for the case
6098 -- of per-object expressions (RM 3.8(18)) occurring in component
6099 -- definition or a discrete subtype definition. Note that we test
6100 -- for a component declaration which includes both cases we are
6101 -- interested in, and furthermore the tree does not have explicit
6102 -- nodes for either of these two constructs.
6106 -- The case we want to test for here is an identifier that is
6107 -- a per-object expression, this is either a discriminant that
6108 -- appears in a context other than the component declaration
6109 -- or it is a reference to the type of the enclosing construct.
6111 -- For either of these cases, we skip the freezing
6113 if not In_Spec_Expression
6116 then
6117 -- We recognize the discriminant case by just looking for
6118 -- a reference to a discriminant. It can only be one for
6119 -- the enclosing construct. Skip freezing in this case.
6124 -- For the case of a reference to the enclosing record,
6125 -- (or task or protected type), we look for a type that
6126 -- matches the current scope.
6133 -- If we have an enumeration literal that appears as the choice in
6134 -- the aggregate of an enumeration representation clause, then
6135 -- freezing does not occur (RM 13.14(10)).
6139 -- The case we are looking for is an enumeration literal
6143 then
6144 -- If enumeration literal appears directly as the choice,
6145 -- do not freeze (this is the normal non-overloaded case)
6149 then
6152 -- If enumeration literal appears as the name of function
6153 -- which is the choice, then also do not freeze. This
6154 -- happens in the overloaded literal case, where the
6155 -- enumeration literal is temporarily changed to a function
6156 -- call for overloading analysis purposes.
6159 and then
6161 and then
6163 then
6168 -- Normally if the parent is a handled sequence of statements,
6169 -- then the current node must be a statement, and that is an
6170 -- appropriate place to insert a freeze node.
6174 -- An exception occurs when the sequence of statements is for
6175 -- an expander generated body that did not do the usual freeze
6176 -- all operation. In this case we usually want to freeze
6177 -- outside this body, not inside it, and we skip past the
6178 -- subprogram body that we are inside.
6181 declare
6185 begin
6186 -- Freeze the entity only when it is declared inside the
6187 -- body of the expander generated procedure. This case
6188 -- is recognized by the scope of the entity or its type,
6189 -- which is either the spec for some enclosing body, or
6190 -- (in the case of init_procs, for which there are no
6191 -- separate specs) the current scope.
6197 or else
6199 then
6205 then
6210 -- An expression function may act as a completion of
6211 -- a function declaration. As such, it can reference
6212 -- entities declared between the two views:
6214 -- Hidden []; -- 1
6215 -- function F return ...;
6216 -- private
6217 -- function Hidden return ...;
6218 -- function F return ... is (Hidden); -- 2
6220 -- Refering to the example above, freezing the expression
6221 -- of F (2) would place Hidden's freeze node (1) in the
6222 -- wrong place. Avoid explicit freezing and let the usual
6223 -- scenarios do the job - for example, reaching the end
6224 -- of the private declarations.
6227 N_Expression_Function
6228 then
6231 -- Freeze outside the body
6233 else
6239 -- Here if normal case where we are in handled statement
6240 -- sequence and want to do the insertion right there.
6242 else
6246 -- If parent is a body or a spec or a block, then the current node
6247 -- is a statement or declaration and we can insert the freeze node
6248 -- before it.
6250 when N_Block_Statement |
6251 N_Entry_Body |
6252 N_Package_Body |
6253 N_Package_Specification |
6254 N_Protected_Body |
6255 N_Subprogram_Body |
6258 -- The expander is allowed to define types in any statements list,
6259 -- so any of the following parent nodes also mark a freezing point
6260 -- if the actual node is in a list of statements or declarations.
6262 when N_Abortable_Part |
6263 N_Accept_Alternative |
6264 N_And_Then |
6265 N_Case_Statement_Alternative |
6266 N_Compilation_Unit_Aux |
6267 N_Conditional_Entry_Call |
6268 N_Delay_Alternative |
6269 N_Elsif_Part |
6270 N_Entry_Call_Alternative |
6271 N_Exception_Handler |
6272 N_Extended_Return_Statement |
6273 N_Freeze_Entity |
6274 N_If_Statement |
6275 N_Or_Else |
6276 N_Selective_Accept |
6277 N_Triggering_Alternative =>
6281 -- Freeze nodes produced by an expression coming from the Actions
6282 -- list of a N_Expression_With_Actions node must remain within the
6283 -- Actions list. Inserting the freeze nodes further up the tree
6284 -- may lead to use before declaration issues in the case of array
6285 -- types.
6290 then
6294 -- Note: N_Loop_Statement is a special case. A type that appears
6295 -- in the source can never be frozen in a loop (this occurs only
6296 -- because of a loop expanded by the expander), so we keep on
6297 -- going. Otherwise we terminate the search. Same is true of any
6298 -- entity which comes from source. (if they have predefined type,
6299 -- that type does not appear to come from source, but the entity
6300 -- should not be frozen here).
6306 -- For all other cases, keep looking at parents
6312 -- We fall through the case if we did not yet find the proper
6313 -- place in the free for inserting the freeze node, so climb.
6318 -- If the expression appears in a record or an initialization procedure,
6319 -- the freeze nodes are collected and attached to the current scope, to
6320 -- be inserted and analyzed on exit from the scope, to insure that
6321 -- generated entities appear in the correct scope. If the expression is
6322 -- a default for a discriminant specification, the scope is still void.
6323 -- The expression can also appear in the discriminant part of a private
6324 -- or concurrent type.
6326 -- If the expression appears in a constrained subcomponent of an
6327 -- enclosing record declaration, the freeze nodes must be attached to
6328 -- the outer record type so they can eventually be placed in the
6329 -- enclosing declaration list.
6331 -- The other case requiring this special handling is if we are in a
6332 -- default expression, since in that case we are about to freeze a
6333 -- static type, and the freeze scope needs to be the outer scope, not
6334 -- the scope of the subprogram with the default parameter.
6336 -- For default expressions and other spec expressions in generic units,
6337 -- the Move_Freeze_Nodes mechanism (see sem_ch12.adb) takes care of
6338 -- placing them at the proper place, after the generic unit.
6341 or else Freeze_Outside
6346 then
6347 declare
6352 begin
6365 -- The current scope may be that of a constrained component of
6366 -- an enclosing record declaration, or of a loop of an enclosing
6367 -- quantified expression, which is above the current scope in the
6368 -- scope stack. Indeed in the context of a quantified expression,
6369 -- a scope is created and pushed above the current scope in order
6370 -- to emulate the loop-like behavior of the quantified expression.
6371 -- If the expression is within a top-level pragma, as for a pre-
6372 -- condition on a library-level subprogram, nothing to do.
6377 N_Quantified_Expression)
6378 then
6385 Freeze_Nodes;
6386 else
6396 -- Now we have the right place to do the freezing. First, a special
6397 -- adjustment, if we are in spec-expression analysis mode, these freeze
6398 -- actions must not be thrown away (normally all inserted actions are
6399 -- thrown away in this mode. However, the freeze actions are from static
6400 -- expressions and one of the important reasons we are doing this
6401 -- special analysis is to get these freeze actions. Therefore we turn
6402 -- off the In_Spec_Expression mode to propagate these freeze actions.
6403 -- This also means they get properly analyzed and expanded.
6407 -- Freeze the designated type of an allocator (RM 13.14(13))
6413 -- Freeze type of expression (RM 13.14(10)). Note that we took care of
6414 -- the enumeration representation clause exception in the loop above.
6420 -- Freeze name if one is present (RM 13.14(11))
6426 -- Restore In_Spec_Expression flag
6431 -----------------------------
6432 -- Freeze_Fixed_Point_Type --
6433 -----------------------------
6435 -- Certain fixed-point types and subtypes, including implicit base types
6436 -- and declared first subtypes, have not yet set up a range. This is
6437 -- because the range cannot be set until the Small and Size values are
6438 -- known, and these are not known till the type is frozen.
6440 -- To signal this case, Scalar_Range contains an unanalyzed syntactic range
6441 -- whose bounds are unanalyzed real literals. This routine will recognize
6442 -- this case, and transform this range node into a properly typed range
6443 -- with properly analyzed and resolved values.
6461 -- Returns size of type with given bounds. Also leaves these
6462 -- bounds set as the current bounds of the Typ.
6464 -----------
6465 -- Fsize --
6466 -----------
6469 begin
6475 -- Start of processing for Freeze_Fixed_Point_Type
6477 begin
6478 -- If Esize of a subtype has not previously been set, set it now
6485 else
6490 -- Immediate return if the range is already analyzed. This means that
6491 -- the range is already set, and does not need to be computed by this
6492 -- routine.
6498 -- Immediate return if either of the bounds raises Constraint_Error
6502 then
6509 -- Ordinary fixed-point case
6513 -- For the ordinary fixed-point case, we are allowed to fudge the
6514 -- end-points up or down by small. Generally we prefer to fudge up,
6515 -- i.e. widen the bounds for non-model numbers so that the end points
6516 -- are included. However there are cases in which this cannot be
6517 -- done, and indeed cases in which we may need to narrow the bounds.
6518 -- The following circuit makes the decision.
6520 -- Note: our terminology here is that Incl_EP means that the bounds
6521 -- are widened by Small if necessary to include the end points, and
6522 -- Excl_EP means that the bounds are narrowed by Small to exclude the
6523 -- end-points if this reduces the size.
6525 -- Note that in the Incl case, all we care about is including the
6526 -- end-points. In the Excl case, we want to narrow the bounds as
6527 -- much as permitted by the RM, to give the smallest possible size.
6544 begin
6545 -- First step. Base types are required to be symmetrical. Right
6546 -- now, the base type range is a copy of the first subtype range.
6547 -- This will be corrected before we are done, but right away we
6548 -- need to deal with the case where both bounds are non-negative.
6549 -- In this case, we set the low bound to the negative of the high
6550 -- bound, to make sure that the size is computed to include the
6551 -- required sign. Note that we do not need to worry about the
6552 -- case of both bounds negative, because the sign will be dealt
6553 -- with anyway. Furthermore we can't just go making such a bound
6554 -- symmetrical, since in a twos-complement system, there is an
6555 -- extra negative value which could not be accommodated on the
6556 -- positive side.
6561 then
6566 -- Compute the fudged bounds. If the number is a model number,
6567 -- then we do nothing to include it, but we are allowed to backoff
6568 -- to the next adjacent model number when we exclude it. If it is
6569 -- not a model number then we straddle the two values with the
6570 -- model numbers on either side.
6576 else
6580 -- The low value excluding the end point is Small greater, but
6581 -- we do not do this exclusion if the low value is positive,
6582 -- since it can't help the size and could actually hurt by
6583 -- crossing the high bound.
6588 -- If the value went from negative to zero, then we have the
6589 -- case where Loval_Incl_EP is the model number just below
6590 -- zero, so we want to stick to the negative value for the
6591 -- base type to maintain the condition that the size will
6592 -- include signed values.
6596 then
6600 else
6604 -- Similar processing for upper bound and high value
6610 else
6616 else
6620 -- One further adjustment is needed. In the case of subtypes, we
6621 -- cannot go outside the range of the base type, or we get
6622 -- peculiarities, and the base type range is already set. This
6623 -- only applies to the Incl values, since clearly the Excl values
6624 -- are already as restricted as they are allowed to be.
6631 -- Get size including and excluding end points
6636 -- No need to exclude end-points if it does not reduce size
6646 -- Now we set the actual size to be used. We want to use the
6647 -- bounds fudged up to include the end-points but only if this
6648 -- can be done without violating a specifically given size
6649 -- size clause or causing an unacceptable increase in size.
6651 -- Case of size clause given
6655 -- Use the inclusive size only if it is consistent with
6656 -- the explicitly specified size.
6663 -- If the inclusive size is too large, we try excluding
6664 -- the end-points (will be caught later if does not work).
6666 else
6672 -- Case of size clause not given
6674 else
6675 -- If we have a base type whose corresponding first subtype
6676 -- has an explicit size that is large enough to include our
6677 -- end-points, then do so. There is no point in working hard
6678 -- to get a base type whose size is smaller than the specified
6679 -- size of the first subtype.
6685 then
6690 -- If excluding the end-points makes the size smaller and
6691 -- results in a size of 8,16,32,64, then we take the smaller
6692 -- size. For the 64 case, this is compulsory. For the other
6693 -- cases, it seems reasonable. We like to include end points
6694 -- if we can, but not at the expense of moving to the next
6695 -- natural boundary of size.
6699 then
6704 -- Otherwise we can definitely include the end points
6706 else
6712 -- One pathological case: normally we never fudge a low bound
6713 -- down, since it would seem to increase the size (if it has
6714 -- any effect), but for ranges containing single value, or no
6715 -- values, the high bound can be small too large. Consider:
6717 -- type t is delta 2.0**(-14)
6718 -- range 131072.0 .. 0;
6720 -- That lower bound is *just* outside the range of 32 bits, and
6721 -- does need fudging down in this case. Note that the bounds
6722 -- will always have crossed here, since the high bound will be
6723 -- fudged down if necessary, as in the case of:
6725 -- type t is delta 2.0**(-14)
6726 -- range 131072.0 .. 131072.0;
6728 -- So we detect the situation by looking for crossed bounds,
6729 -- and if the bounds are crossed, and the low bound is greater
6730 -- than zero, we will always back it off by small, since this
6731 -- is completely harmless.
6738 -- And of course, we need to do exactly the same parallel
6739 -- fudge for flat ranges in the negative region.
6752 -- For the decimal case, none of this fudging is required, since there
6753 -- are no end-point problems in the decimal case (the end-points are
6754 -- always included).
6756 else
6760 -- At this stage, the actual size has been calculated and the proper
6761 -- required bounds are stored in the low and high bounds.
6765 Error_Msg_N
6767 Typ);
6771 -- Check size against explicit given size
6777 Error_Msg_NE
6781 else
6785 -- Increase size to next natural boundary if no size clause given
6787 else
6794 else
6802 -- If we have a base type, then expand the bounds so that they extend to
6803 -- the full width of the allocated size in bits, to avoid junk range
6804 -- checks on intermediate computations.
6811 -- Final step is to reanalyze the bounds using the proper type
6812 -- and set the Corresponding_Integer_Value fields of the literals.
6818 -- Resolve with universal fixed if the base type, and the base type if
6819 -- it is a subtype. Note we can't resolve the base type with itself,
6820 -- that would be a reference before definition.
6824 else
6828 -- Set corresponding integer value for bound
6830 Set_Corresponding_Integer_Value
6833 -- Similar processing for high bound
6841 else
6845 Set_Corresponding_Integer_Value
6848 -- Set type of range to correspond to bounds
6852 -- Set Esize to calculated size if not set already
6858 -- Set RM_Size if not already set. If already set, check value
6860 declare
6863 begin
6868 Error_Msg_NE
6873 else
6879 ------------------
6880 -- Freeze_Itype --
6881 ------------------
6886 begin
6895 --------------------------
6896 -- Freeze_Static_Object --
6897 --------------------------
6902 -- Exception raised if the type of a static object cannot be made
6903 -- static. This happens if the type depends on non-global objects.
6906 -- Called to ensure that an expression used as part of a type definition
6907 -- is statically allocatable, which means that the expression type is
6908 -- statically allocatable, and the expression is either static, or a
6909 -- reference to a library level constant.
6912 -- Called to mark a type as static, checking that it is possible
6913 -- to set the type as static. If it is not possible, then the
6914 -- exception Cannot_Be_Static is raised.
6916 -----------------------------
6917 -- Ensure_Expression_Is_SA --
6918 -----------------------------
6923 begin
6935 then
6943 -----------------------
6944 -- Ensure_Type_Is_SA --
6945 -----------------------
6951 begin
6952 -- If type is library level, we are all set
6958 -- We are also OK if the type already marked as statically allocated,
6959 -- which means we processed it before.
6965 -- Mark type as statically allocated
6969 -- Check that it is safe to statically allocate this type
6987 declare
6991 begin
7003 else
7012 then
7031 else
7036 -- Start of processing for Freeze_Static_Object
7038 begin
7041 exception
7044 -- If the object that cannot be static is imported or exported, then
7045 -- issue an error message saying that this object cannot be imported
7046 -- or exported. If it has an address clause it is an overlay in the
7047 -- current partition and the static requirement is not relevant.
7048 -- Do not issue any error message when ignoring rep clauses.
7055 Error_Msg_N
7059 -- Otherwise must be exported, something is wrong if compiler
7060 -- is marking something as statically allocated which cannot be).
7063 Error_Msg_N
7068 -----------------------
7069 -- Freeze_Subprogram --
7070 -----------------------
7076 begin
7077 -- Subprogram may not have an address clause unless it is imported
7081 Error_Msg_N
7088 -- Reset the Pure indication on an imported subprogram unless an
7089 -- explicit Pure_Function pragma was present or the subprogram is an
7090 -- intrinsic. We do this because otherwise it is an insidious error
7091 -- to call a non-pure function from pure unit and have calls
7092 -- mysteriously optimized away. What happens here is that the Import
7093 -- can bypass the normal check to ensure that pure units call only pure
7094 -- subprograms.
7096 -- The reason for the intrinsic exception is that in general, intrinsic
7097 -- functions (such as shifts) are pure anyway. The only exceptions are
7098 -- the intrinsics in GNAT.Source_Info, and that unit is not marked Pure
7099 -- in any case, so no problem arises.
7105 then
7109 -- For non-foreign convention subprograms, this is where we create
7110 -- the extra formals (for accessibility level and constrained bit
7111 -- information). We delay this till the freeze point precisely so
7112 -- that we know the convention.
7118 -- If this is convention Ada and a Valued_Procedure, that's odd
7123 and then Warn_On_Export_Import
7124 then
7125 Error_Msg_N
7130 -- Case of foreign convention
7132 else
7135 -- For foreign conventions, warn about return of unconstrained array
7140 -- If no return type, probably some other error, e.g. a
7141 -- missing full declaration, so ignore.
7146 -- If the return type is generic, we have emitted a warning
7147 -- earlier on, and there is nothing else to check here. Specific
7148 -- instantiations may lead to erroneous behavior.
7153 -- Display warning if returning unconstrained array
7158 -- Check appropriate warning is enabled (should we check for
7159 -- Warnings (Off) on specific entities here, probably so???)
7161 and then Warn_On_Export_Import
7163 -- Exclude the VM case, since return of unconstrained arrays
7164 -- is properly handled in both the JVM and .NET cases.
7167 then
7168 Error_Msg_N
7175 -- If any of the formals for an exported foreign convention
7176 -- subprogram have defaults, then emit an appropriate warning since
7177 -- this is odd (default cannot be used from non-Ada code)
7182 if Warn_On_Export_Import
7184 then
7185 Error_Msg_N
7195 -- Pragma Inline_Always is disallowed for dispatching subprograms
7196 -- because the address of such subprograms is saved in the dispatch
7197 -- table to support dispatching calls, and dispatching calls cannot
7198 -- be inlined. This is consistent with the restriction against using
7199 -- 'Access or 'Address on an Inline_Always subprogram.
7203 then
7204 Error_Msg_N
7208 -- Because of the implicit representation of inherited predefined
7209 -- operators in the front-end, the overriding status of the operation
7210 -- may be affected when a full view of a type is analyzed, and this is
7211 -- not captured by the analysis of the corresponding type declaration.
7212 -- Therefore the correctness of a not-overriding indicator must be
7213 -- rechecked when the subprogram is frozen.
7217 then
7222 ----------------------
7223 -- Is_Fully_Defined --
7224 ----------------------
7227 begin
7236 then
7237 -- Verify that the record type has no components with private types
7238 -- without completion.
7240 declare
7243 begin
7255 -- For the designated type of an access to subprogram, all types in
7256 -- the profile must be fully defined.
7259 declare
7262 begin
7275 else
7281 ---------------------------------
7282 -- Process_Default_Expressions --
7283 ---------------------------------
7285 procedure Process_Default_Expressions
7288 is
7295 begin
7298 -- A subprogram instance and its associated anonymous subprogram share
7299 -- their signature. The default expression functions are defined in the
7300 -- wrapper packages for the anonymous subprogram, and should not be
7301 -- generated again for the instance.
7306 then
7314 -- We work with a copy of the default expression because we
7315 -- do not want to disturb the original, since this would mess
7316 -- up the conformance checking.
7320 -- The analysis of the expression may generate insert actions,
7321 -- which of course must not be executed. We wrap those actions
7322 -- in a procedure that is not called, and later on eliminated.
7323 -- The following cases have no side-effects, and are analyzed
7324 -- directly.
7328 N_Integer_Literal,
7329 N_Character_Literal,
7330 N_String_Literal,
7331 N_Real_Literal)
7335 then
7336 -- If there is no default function, we must still do a full
7337 -- analyze call on the default value, to ensure that all error
7338 -- checks are performed, e.g. those associated with static
7339 -- evaluation. Note: this branch will always be taken if the
7340 -- analyzer is turned off (but we still need the error checks).
7342 -- Note: the setting of parent here is to meet the requirement
7343 -- that we can only analyze the expression while attached to
7344 -- the tree. Really the requirement is that the parent chain
7345 -- be set, we don't actually need to be in the tree.
7350 -- Default expressions are resolved with their own type if the
7351 -- context is generic, to avoid anomalies with private types.
7355 else
7359 -- If that resolved expression will raise constraint error,
7360 -- then flag the default value as raising constraint error.
7361 -- This allows a proper error message on the calls.
7367 -- If the default is a parameterless call, we use the name of
7368 -- the called function directly, and there is no body to build.
7372 then
7375 -- Else construct and analyze the body of a wrapper procedure
7376 -- that contains an object declaration to hold the expression.
7377 -- Given that this is done only to complete the analysis, it
7378 -- simpler to build a procedure than a function which might
7379 -- involve secondary stack expansion.
7381 else
7384 Dbody :=
7386 Specification =>
7393 Object_Definition =>
7397 Handled_Statement_Sequence =>
7414 ----------------------------------------
7415 -- Set_Component_Alignment_If_Not_Set --
7416 ----------------------------------------
7419 begin
7420 -- Ignore if not base type, subtypes don't need anything
7426 -- Do not override existing representation
7437 else
7438 Set_Component_Alignment
7444 --------------------------
7445 -- Set_SSO_From_Default --
7446 --------------------------
7449 begin
7452 then
7454 or else
7456 then
7457 -- If flags cause reverse storage order, then set the result. Note
7458 -- that we would have ignored the pragma setting the non default
7459 -- storage order in any case, hence the assertion at this point.
7467 ------------------
7468 -- Undelay_Type --
7469 ------------------
7472 begin
7476 -- Since we don't want T to have a Freeze_Node, we don't want its
7477 -- Full_View or Corresponding_Record_Type to have one either.
7479 -- ??? Fundamentally, this whole handling is unpleasant. What we really
7480 -- want is to be sure that for an Itype that's part of record R and is a
7481 -- subtype of type T, that it's frozen after the later of the freeze
7482 -- points of R and T. We have no way of doing that directly, so what we
7483 -- do is force most such Itypes to be frozen as part of freezing R via
7484 -- this procedure and only delay the ones that need to be delayed
7485 -- (mostly the designated types of access types that are defined as part
7486 -- of the record).
7492 then
7500 then
7505 ------------------
7506 -- Warn_Overlay --
7507 ------------------
7509 procedure Warn_Overlay
7513 is
7515 -- The object to which the address clause applies
7521 begin
7522 -- No warning if address clause overlay warnings are off
7528 -- No warning if there is an explicit initialization
7536 -- We only give the warning for non-imported entities of a type for
7537 -- which a non-null base init proc is defined, or for objects of access
7538 -- types with implicit null initialization, or when Normalize_Scalars
7539 -- applies and the type is scalar or a string type (the latter being
7540 -- tested for because predefined String types are initialized by inline
7541 -- code rather than by an init_proc). Note that we do not give the
7542 -- warning for Initialize_Scalars, since we suppressed initialization
7543 -- in this case. Also, do not warn if Suppress_Initialization is set.
7553 then
7556 then
7561 then
7568 then
7575 -- A function call (most likely to To_Address) is probably not an
7576 -- overlay, so skip warning. Ditto if the function call was inlined
7577 -- and transformed into an entity.
7585 -- If a pragma Import follows, we assume that it is for the current
7586 -- target of the address clause, and skip the warning.
7591 then
7597 Error_Msg_N
7599 Nam);
7600 else
7601 Error_Msg_N
7603 Nam);
7606 -- Add friendly warning if initialization comes from a packed array
7607 -- component.
7610 declare
7613 begin
7618 then
7622 then
7623 Error_Msg_NE
7628 else
7635 Error_Msg_N
7638 Nam);