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1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- F R E E Z E --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1992-2014, Free Software Foundation, Inc. --
10 -- --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
20 -- --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
23 -- --
24 ------------------------------------------------------------------------------
72 -----------------------
73 -- Local Subprograms --
74 -----------------------
77 -- Typ is a type that is being frozen. If no size clause is given,
78 -- but a default Esize has been computed, then this default Esize is
79 -- adjusted up if necessary to be consistent with a given alignment,
80 -- but never to a value greater than Long_Long_Integer'Size. This
81 -- is used for all discrete types and for fixed-point types.
83 procedure Build_And_Analyze_Renamed_Body
87 -- Build body for a renaming declaration, insert in tree and analyze
90 -- Apply legality checks to address clauses for object declarations,
91 -- at the point the object is frozen. Also ensure any initialization is
92 -- performed only after the object has been frozen.
94 procedure Check_Component_Storage_Order
99 -- For an Encl_Type that has a Scalar_Storage_Order attribute definition
100 -- clause, verify that the component type has an explicit and compatible
101 -- attribute/aspect. For arrays, Comp is Empty; for records, it is the
102 -- entity of the component under consideration. For an Encl_Type that
103 -- does not have a Scalar_Storage_Order attribute definition clause,
104 -- verify that the component also does not have such a clause.
105 -- ADC is the attribute definition clause if present (or Empty). On return,
106 -- Comp_ADC_Present is set True if the component has a Scalar_Storage_Order
107 -- attribute definition clause.
110 -- When an expression function is frozen by a use of it, the expression
111 -- itself is frozen. Check that the expression does not include references
112 -- to deferred constants without completion. We report this at the freeze
113 -- point of the function, to provide a better error message.
114 --
115 -- In most cases the expression itself is frozen by the time the function
116 -- itself is frozen, because the formals will be frozen by then. However,
117 -- Attribute references to outer types are freeze points for those types;
118 -- this routine generates the required freeze nodes for them.
121 -- E is a base type. If E is tagged or has a component that is aliased
122 -- or tagged or contains something this is aliased or tagged, set
123 -- Strict_Alignment.
127 -- If E is a fixed-point or discrete type, then all the necessary work
128 -- to freeze it is completed except for possible setting of the flag
129 -- Is_Unsigned_Type, which is done by this procedure. The call has no
130 -- effect if the entity E is not a discrete or fixed-point type.
132 procedure Freeze_And_Append
136 -- Freezes Ent using Freeze_Entity, and appends the resulting list of
137 -- nodes to Result, modifying Result from No_List if necessary. N has
138 -- the same usage as in Freeze_Entity.
141 -- Freeze enumeration type. The Esize field is set as processing
142 -- proceeds (i.e. set by default when the type is declared and then
143 -- adjusted by rep clauses. What this procedure does is to make sure
144 -- that if a foreign convention is specified, and no specific size
145 -- is given, then the size must be at least Integer'Size.
148 -- If an object is frozen which has Is_Statically_Allocated set, then
149 -- all referenced types must also be marked with this flag. This routine
150 -- is in charge of meeting this requirement for the object entity E.
153 -- Perform freezing actions for a subprogram (create extra formals,
154 -- and set proper default mechanism values). Note that this routine
155 -- is not called for internal subprograms, for which neither of these
156 -- actions is needed (or desirable, we do not want for example to have
157 -- these extra formals present in initialization procedures, where they
158 -- would serve no purpose). In this call E is either a subprogram or
159 -- a subprogram type (i.e. an access to a subprogram).
162 -- True if T is not private and has no private components, or has a full
163 -- view. Used to determine whether the designated type of an access type
164 -- should be frozen when the access type is frozen. This is done when an
165 -- allocator is frozen, or an expression that may involve attributes of
166 -- the designated type. Otherwise freezing the access type does not freeze
167 -- the designated type.
169 procedure Process_Default_Expressions
172 -- This procedure is called for each subprogram to complete processing of
173 -- default expressions at the point where all types are known to be frozen.
174 -- The expressions must be analyzed in full, to make sure that all error
175 -- processing is done (they have only been pre-analyzed). If the expression
176 -- is not an entity or literal, its analysis may generate code which must
177 -- not be executed. In that case we build a function body to hold that
178 -- code. This wrapper function serves no other purpose (it used to be
179 -- called to evaluate the default, but now the default is inlined at each
180 -- point of call).
183 -- Typ is a record or array type that is being frozen. This routine sets
184 -- the default component alignment from the scope stack values if the
185 -- alignment is otherwise not specified.
188 -- As each entity is frozen, this routine is called to deal with the
189 -- setting of Debug_Info_Needed for the entity. This flag is set if
190 -- the entity comes from source, or if we are in Debug_Generated_Code
191 -- mode or if the -gnatdV debug flag is set. However, it never sets
192 -- the flag if Debug_Info_Off is set. This procedure also ensures that
193 -- subsidiary entities have the flag set as required.
196 -- T is a record or array type that is being frozen. If it is a base type,
197 -- and if SSO_Set_Low/High_By_Default is set, then Reverse_Storage order
198 -- will be set appropriately. Note that an explicit occurrence of aspect
199 -- Scalar_Storage_Order or an explicit setting of this aspect with an
200 -- attribute definition clause occurs, then these two flags are reset in
201 -- any case, so call will have no effect.
204 -- T is a type of a component that we know to be an Itype. We don't want
205 -- this to have a Freeze_Node, so ensure it doesn't. Do the same for any
206 -- Full_View or Corresponding_Record_Type.
208 procedure Warn_Overlay
212 -- Expr is the expression for an address clause for entity Nam whose type
213 -- is Typ. If Typ has a default initialization, and there is no explicit
214 -- initialization in the source declaration, check whether the address
215 -- clause might cause overlaying of an entity, and emit a warning on the
216 -- side effect that the initialization will cause.
218 -------------------------------
219 -- Adjust_Esize_For_Alignment --
220 -------------------------------
225 begin
231 then
237 ------------------------------------
238 -- Build_And_Analyze_Renamed_Body --
239 ------------------------------------
241 procedure Build_And_Analyze_Renamed_Body
245 is
251 begin
252 -- If the renamed subprogram is intrinsic, there is no need for a
253 -- wrapper body: we set the alias that will be called and expanded which
254 -- completes the declaration. This transformation is only legal if the
255 -- renamed entity has already been elaborated.
257 -- Note that it is legal for a renaming_as_body to rename an intrinsic
258 -- subprogram, as long as the renaming occurs before the new entity
259 -- is frozen (RM 8.5.4 (5)).
263 then
265 else
271 and then
275 -- We can make the renaming entity intrinsic if the renamed function
276 -- has an interface name, or if it is one of the shift/rotate
277 -- operations known to the compiler.
279 and then
282 Name_Rotate_Right,
283 Name_Shift_Left,
284 Name_Shift_Right,
285 Name_Shift_Right_Arithmetic))
286 then
291 else
298 else
307 ------------------------
308 -- Build_Renamed_Body --
309 ------------------------
311 function Build_Renamed_Body
314 is
316 -- We use for the source location of the renamed body, the location of
317 -- the spec entity. It might seem more natural to use the location of
318 -- the renaming declaration itself, but that would be wrong, since then
319 -- the body we create would look as though it was created far too late,
320 -- and this could cause problems with elaboration order analysis,
321 -- particularly in connection with instantiations.
336 -- If the renamed entity is a primitive operation given in prefix form,
337 -- the prefix is the target object and it has to be added as the first
338 -- actual in the generated call.
340 begin
341 -- Determine the entity being renamed, which is the target of the call
342 -- statement. If the name is an explicit dereference, this is a renaming
343 -- of a subprogram type rather than a subprogram. The name itself is
344 -- fully analyzed.
355 else
362 else
368 -- If the renamed entity is a predefined operator, retain full name
369 -- to ensure its visibility.
373 then
375 else
379 else
382 and then
385 then
387 -- Retrieve the target object, to be added as a first actual
388 -- in the call.
393 else
397 -- Original name may have been overloaded, but is fully resolved now
402 -- For simple renamings, subsequent calls can be expanded directly as
403 -- calls to the renamed entity. The body must be generated in any case
404 -- for calls that may appear elsewhere. This is not done in the case
405 -- where the subprogram is an instantiation because the actual proper
406 -- body has not been built yet.
411 then
415 -- The body generated for this renaming is an internal artifact, and
416 -- does not constitute a freeze point for the called entity.
423 declare
427 begin
428 -- The controlling formal may be an access parameter, or the
429 -- actual may be an access value, so adjust accordingly.
433 then
434 Actuals := New_List
439 then
440 Actuals := New_List
444 else
452 else
463 -- If the renamed entity is an entry, inherit its profile. For other
464 -- renamings as bodies, both profiles must be subtype conformant, so it
465 -- is not necessary to replace the profile given in the declaration.
466 -- However, default values that are aggregates are rewritten when
467 -- partially analyzed, so we recover the original aggregate to insure
468 -- that subsequent conformity checking works. Similarly, if the default
469 -- expression was constant-folded, recover the original expression.
479 N_Access_Definition
480 then
488 then
499 -- If the renamed entity is a function, the generated body contains a
500 -- return statement. Otherwise, build a procedure call. If the entity is
501 -- an entry, subsequent analysis of the call will transform it into the
502 -- proper entry or protected operation call. If the renamed entity is
503 -- a character literal, return it directly.
509 then
510 Call_Node :=
512 Expression =>
518 Call_Node :=
523 Call_Node :=
527 else
528 Call_Node :=
534 -- Create entities for subprogram body and formals
547 Body_Node :=
551 Handled_Statement_Sequence =>
561 -- Link the body to the entity whose declaration it completes. If
562 -- the body is analyzed when the renamed entity is frozen, it may
563 -- be necessary to restore the proper scope (see package Exp_Ch13).
567 then
569 else
576 --------------------------
577 -- Check_Address_Clause --
578 --------------------------
589 begin
596 -- Has_Delayed_Freeze was set on E when the address clause was
597 -- analyzed, and must remain set because we want the address
598 -- clause to be elaborated only after any entity it references
599 -- has been elaborated.
602 -- If Rep_Clauses are to be ignored, remove address clause from
603 -- list attached to entity, because it may be illegal for gigi,
604 -- for example by breaking order of elaboration..
607 declare
610 begin
616 else
619 loop
629 -- And now remove the address clause
635 then
641 -- Capture initialization value at point of declaration,
642 -- and make explicit assignment legal, because object may
643 -- be a constant.
649 -- Move initialization to freeze actions (once the object has
650 -- been frozen, and the address clause alignment check has been
651 -- performed.
660 -- If the objet is tagged, check whether the tag must be
661 -- reassigned expliitly.
671 -----------------------------
672 -- Check_Compile_Time_Size --
673 -----------------------------
678 -- Sets the compile time known size (32 bits or less) in the Esize
679 -- field, of T checking for a size clause that was given which attempts
680 -- to give a smaller size, and also checking for an alignment clause.
683 -- Recursive function that does all the work
686 -- If T is a constrained subtype, its size is not known if any of its
687 -- discriminant constraints is not static and it is not a null record.
688 -- The test is conservative and doesn't check that the components are
689 -- in fact constrained by non-static discriminant values. Could be made
690 -- more precise ???
692 --------------------
693 -- Set_Small_Size --
694 --------------------
697 begin
701 -- Check for bad size clause given
706 Error_Msg_NE
711 -- Set size if not set already
718 ----------------
719 -- Size_Known --
720 ----------------
729 begin
733 -- Always True for scalar types. This is true even for generic formal
734 -- scalar types. We used to return False in the latter case, but the
735 -- size is known at compile time, even in the template, we just do
736 -- not know the exact size but that's not the point of this routine.
740 then
743 -- Array types
747 -- String literals always have known size, and we can set it
754 -- Unconstrained types never have known at compile time size
759 -- Don't do any recursion on type with error posted, since we may
760 -- have a malformed type that leads us into a loop.
765 -- Otherwise if component size unknown, then array size unknown
771 -- Check for all indexes static, and also compute possible size
772 -- (in case it is less than 32 and may be packable).
774 declare
778 begin
787 else
795 then
798 else
803 else
815 -- Access types always have known at compile time sizes
820 -- For non-generic private types, go to underlying type if present
825 then
826 -- Don't do any recursion on type with error posted, since we may
827 -- have a malformed type that leads us into a loop.
831 else
835 -- Record types
839 -- A class-wide type is never considered to have a known size
844 -- A subtype of a variant record must not have non-static
845 -- discriminated components.
849 then
852 -- Don't do any recursion on type with error posted, since we may
853 -- have a malformed type that leads us into a loop.
859 -- Now look at the components of the record
861 declare
862 -- The following two variables are used to keep track of the
863 -- size of packed records if we can tell the size of the packed
864 -- record in the front end. Packed_Size_Known is True if so far
865 -- we can figure out the size. It is initialized to True for a
866 -- packed record, unless the record has discriminants or atomic
867 -- components or independent components.
869 -- The reason we eliminate the discriminated case is that
870 -- we don't know the way the back end lays out discriminated
871 -- packed records. If Packed_Size_Known is True, then
872 -- Packed_Size is the size in bits so far.
881 -- Size in bits so far
883 begin
884 -- Test for variant part present
890 N_Record_Definition
892 and then
893 Present (Variant_Part
895 then
896 -- If variant part is present, and type is unconstrained,
897 -- then we must have defaulted discriminants, or a size
898 -- clause must be present for the type, or else the size
899 -- is definitely not known at compile time.
902 and then
905 then
910 -- Loop through components
916 -- We do not know the packed size if there is a component
917 -- clause present (we possibly could, but this would only
918 -- help in the case of a record with partial rep clauses.
919 -- That's because in the case of full rep clauses, the
920 -- size gets figured out anyway by a different circuit).
926 -- We do not know the packed size if we have a by reference
927 -- type, or an atomic type or an atomic component, or an
928 -- aliased component (because packing does not touch these).
934 then
938 -- We need to identify a component that is an array where
939 -- the index type is an enumeration type with non-standard
940 -- representation, and some bound of the type depends on a
941 -- discriminant.
943 -- This is because gigi computes the size by doing a
944 -- substitution of the appropriate discriminant value in
945 -- the size expression for the base type, and gigi is not
946 -- clever enough to evaluate the resulting expression (which
947 -- involves a call to rep_to_pos) at compile time.
949 -- It would be nice if gigi would either recognize that
950 -- this expression can be computed at compile time, or
951 -- alternatively figured out the size from the subtype
952 -- directly, where all the information is at hand ???
956 then
957 declare
965 begin
972 then
978 then
983 then
993 -- Clearly size of record is not known if the size of one of
994 -- the components is not known.
1000 -- Accumulate packed size if possible
1004 -- We can only deal with elementary types, since for
1005 -- non-elementary components, alignment enters into the
1006 -- picture, and we don't know enough to handle proper
1007 -- alignment in this context. Packed arrays count as
1008 -- elementary if the representation is a modular type.
1012 and then Present
1014 and then Is_Modular_Integer_Type
1016 then
1017 -- Packed size unknown if we have an atomic type
1018 -- or a by reference type, since the back end
1019 -- knows how these are layed out.
1023 then
1026 -- If RM_Size is known and static, then we can keep
1027 -- accumulating the packed size
1031 -- A little glitch, to be removed sometime ???
1032 -- gigi does not understand zero sizes yet.
1037 -- Normal case where we can keep accumulating the
1038 -- packed array size.
1040 else
1044 -- If we have a field whose RM_Size is not known then
1045 -- we can't figure out the packed size here.
1047 else
1051 -- If we have a non-elementary type we can't figure out
1052 -- the packed array size (alignment issues).
1054 else
1069 -- All other cases, size not known at compile time
1071 else
1076 -------------------------------------
1077 -- Static_Discriminated_Components --
1078 -------------------------------------
1080 function Static_Discriminated_Components
1082 is
1085 begin
1089 then
1103 -- Start of processing for Check_Compile_Time_Size
1105 begin
1109 -----------------------------------
1110 -- Check_Component_Storage_Order --
1111 -----------------------------------
1113 procedure Check_Component_Storage_Order
1118 is
1124 -- Set for the record case, True if Comp starts on a byte boundary
1125 -- (in which case it is allowed to have different storage order).
1128 -- Set True when the component is a nested composite, and it does not
1129 -- have the same scalar storage order as Encl_Type.
1133 begin
1134 -- Record case
1144 else
1145 -- If a component clause is present, check if the component starts
1146 -- on a storage element boundary. Otherwise conservatively assume
1147 -- it does so only in the case where the record is not packed.
1150 Comp_Byte_Aligned :=
1152 else
1159 -- Array case
1161 else
1168 -- Note: the Reverse_Storage_Order flag is set on the base type, but
1169 -- the attribute definition clause is attached to the first subtype.
1172 Comp_ADC := Get_Attribute_Definition_Clause
1174 Attribute_Scalar_Storage_Order);
1177 -- Case of record or array component: check storage order compatibility
1180 Comp_SSO_Differs :=
1182 /=
1185 -- Parent and extension must have same storage order
1189 Error_Msg_N
1194 -- If enclosing composite has explicit SSO then nested composite must
1195 -- have explicit SSO as well.
1201 -- If component and composite SSO differs, check that component
1202 -- falls on byte boundaries and isn't packed.
1206 -- Component SSO differs from enclosing composite:
1208 -- Reject if component is a packed array, as it may be represented
1209 -- as a scalar internally.
1212 Error_Msg_N
1216 -- Reject if composite is a packed array, as it may be rewritten
1217 -- into an array of scalars.
1223 -- Reject if not byte aligned
1226 and then not Comp_Byte_Aligned
1227 then
1228 Error_Msg_N
1234 -- Enclosing type has explicit SSO: non-composite component must not
1235 -- be aliased.
1238 Error_Msg_N
1244 -----------------------------
1245 -- Check_Debug_Info_Needed --
1246 -----------------------------
1249 begin
1254 or else Debug_Generated_Code
1255 or else Debug_Flag_VV
1257 then
1262 -------------------------------
1263 -- Check_Expression_Function --
1264 -------------------------------
1270 -- Function to search for deferred constant
1272 -------------------
1273 -- Find_Constant --
1274 -------------------
1277 begin
1278 -- When a constant is initialized with the result of a dispatching
1279 -- call, the constant declaration is rewritten as a renaming of the
1280 -- displaced function result. This scenario is not a premature use of
1281 -- a constant even though the Has_Completion flag is not set.
1288 N_Object_Declaration
1291 then
1292 Error_Msg_NE
1300 then
1310 -- Start of processing for Check_Expression_Function
1312 begin
1317 then
1322 ----------------------------
1323 -- Check_Strict_Alignment --
1324 ----------------------------
1329 begin
1347 then
1357 -------------------------
1358 -- Check_Unsigned_Type --
1359 -------------------------
1366 begin
1371 -- Do not attempt to analyze case where range was in error
1377 -- The situation that is non trivial is something like
1379 -- subtype x1 is integer range -10 .. +10;
1380 -- subtype x2 is x1 range 0 .. V1;
1381 -- subtype x3 is x2 range V2 .. V3;
1382 -- subtype x4 is x3 range V4 .. V5;
1384 -- where Vn are variables. Here the base type is signed, but we still
1385 -- know that x4 is unsigned because of the lower bound of x2.
1387 -- The only way to deal with this is to look up the ancestor chain
1390 loop
1404 else
1407 -- If no ancestor had a static lower bound, go to base type
1411 -- Note: the reason we still check for a compile time known
1412 -- value for the base type is that at least in the case of
1413 -- generic formals, we can have bounds that fail this test,
1414 -- and there may be other cases in error situations.
1426 then
1436 -------------------------
1437 -- Is_Atomic_Aggregate --
1438 -------------------------
1440 function Is_Atomic_Aggregate
1443 is
1449 begin
1452 -- Array may be qualified, so find outer context
1460 then
1462 New_N :=
1473 else
1478 -----------------------------------------------
1479 -- Explode_Initialization_Compound_Statement --
1480 -----------------------------------------------
1485 begin
1488 then
1491 -- Note that we rewrite Init_Stmts into a NULL statement, rather than
1492 -- just removing it, because Freeze_All may rely on this particular
1493 -- Node_Id still being present in the enclosing list to know where to
1494 -- stop freezing.
1502 ----------------
1503 -- Freeze_All --
1504 ----------------
1506 -- Note: the easy coding for this procedure would be to just build a
1507 -- single list of freeze nodes and then insert them and analyze them
1508 -- all at once. This won't work, because the analysis of earlier freeze
1509 -- nodes may recursively freeze types which would otherwise appear later
1510 -- on in the freeze list. So we must analyze and expand the freeze nodes
1511 -- as they are generated.
1518 -- This is the internal recursive routine that does freezing of entities
1519 -- (but NOT the analysis of default expressions, which should not be
1520 -- recursive, we don't want to analyze those till we are sure that ALL
1521 -- the types are frozen).
1523 --------------------
1524 -- Freeze_All_Ent --
1525 --------------------
1533 -- If freeze nodes are present, insert and analyze, and reset cursor
1534 -- for next insertion.
1536 -------------------
1537 -- Process_Flist --
1538 -------------------
1541 begin
1548 else
1554 -- Start or processing for Freeze_All_Ent
1556 begin
1560 -- If the entity is an inner package which is not a package
1561 -- renaming, then its entities must be frozen at this point. Note
1562 -- that such entities do NOT get frozen at the end of the nested
1563 -- package itself (only library packages freeze).
1565 -- Same is true for task declarations, where anonymous records
1566 -- created for entry parameters must be frozen.
1572 then
1583 then
1590 N_Single_Task_Declaration)
1591 then
1594 End_Scope;
1596 -- For a derived tagged type, we must ensure that all the
1597 -- primitive operations of the parent have been frozen, so that
1598 -- their addresses will be in the parent's dispatch table at the
1599 -- point it is inherited.
1605 then
1606 declare
1613 begin
1620 then
1622 Process_Flist;
1632 Process_Flist;
1634 -- If already frozen, and there are delayed aspects, this is where
1635 -- we do the visibility check for these aspects (see Sem_Ch13 spec
1636 -- for a description of how we handle aspect visibility).
1640 -- Retrieve the visibility to the discriminants in order to
1641 -- analyze properly the aspects.
1645 declare
1648 begin
1654 then
1665 -- If an incomplete type is still not frozen, this may be a
1666 -- premature freezing because of a body declaration that follows.
1667 -- Indicate where the freezing took place. Freezing will happen
1668 -- if the body comes from source, but not if it is internally
1669 -- generated, for example as the body of a type invariant.
1671 -- If the freezing is caused by the end of the current declarative
1672 -- part, it is a Taft Amendment type, and there is no error.
1676 then
1677 declare
1680 begin
1681 -- The presence of a body freezes all entities previously
1682 -- declared in the current list of declarations, but this
1683 -- does not apply if the body does not come from source.
1684 -- A type invariant is transformed into a subprogram body
1685 -- which is placed at the end of the private part of the
1686 -- current package, but this body does not freeze incomplete
1687 -- types that may be declared in this private part.
1690 N_Entry_Body,
1691 N_Package_Body,
1692 N_Protected_Body,
1693 N_Task_Body)
1695 and then
1698 then
1700 Error_Msg_NE
1711 -- Start of processing for Freeze_All
1713 begin
1716 -- Now that all types are frozen, we can deal with default expressions
1717 -- that require us to build a default expression functions. This is the
1718 -- point at which such functions are constructed (after all types that
1719 -- might be used in such expressions have been frozen).
1721 -- For subprograms that are renaming_as_body, we create the wrapper
1722 -- bodies as needed.
1724 -- We also add finalization chains to access types whose designated
1725 -- types are controlled. This is normally done when freezing the type,
1726 -- but this misses recursive type definitions where the later members
1727 -- of the recursion introduce controlled components.
1729 -- Loop through entities
1744 else
1750 and then
1752 = N_Subprogram_Renaming_Declaration
1753 then
1754 Build_And_Analyze_Renamed_Body
1761 N_Single_Task_Declaration)
1762 then
1763 declare
1766 begin
1771 then
1779 -- We add finalization masters to access types whose designated types
1780 -- require finalization. This is normally done when freezing the
1781 -- type, but this misses recursive type definitions where the later
1782 -- members of the recursion introduce controlled components (such as
1783 -- can happen when incomplete types are involved), as well cases
1784 -- where a component type is private and the controlled full type
1785 -- occurs after the access type is frozen. Cases that don't need a
1786 -- finalization master are generic formal types (the actual type will
1787 -- have it) and types derived from them, and types with Java and CIL
1788 -- conventions, since those are used for API bindings.
1789 -- (Are there any other cases that should be excluded here???)
1795 then
1803 -----------------------
1804 -- Freeze_And_Append --
1805 -----------------------
1807 procedure Freeze_And_Append
1811 is
1813 begin
1817 else
1823 -------------------
1824 -- Freeze_Before --
1825 -------------------
1830 begin
1840 -------------------
1841 -- Freeze_Entity --
1842 -------------------
1853 -- This could use a comment ???
1856 -- Used to detect attempt to freeze function declared in another unit
1859 -- List of freezing actions, left at No_List if none
1862 -- This flag gets set to true for a variable with default initialization
1865 -- N is a freezing action to be appended to the Result
1868 -- If Loc is a freeze_entity that appears after the last declaration
1869 -- in the scope, inhibit error messages on late completion.
1872 -- Check that an Access or Unchecked_Access attribute with a prefix
1873 -- which is the current instance type can only be applied when the type
1874 -- is limited.
1877 -- Give warning for modulus of 8, 16, 32, or 64 given as an explicit
1878 -- integer literal without an explicit corresponding size clause. The
1879 -- caller has checked that Utype is a modular integer type.
1882 -- Freeze array type, including freezing index and component types
1885 -- Create Freeze_Generic_Entity nodes for types declared in a generic
1886 -- package. Recurse on inner generic packages.
1889 -- Freeze formals and return type of subprogram. If some type in the
1890 -- profile is a limited view, freezing of the entity will take place
1891 -- elsewhere, and the function returns False. This routine will be
1892 -- modified if and when we can implement AI05-019 efficiently ???
1895 -- Freeze record type, including freezing component types, and freezing
1896 -- primitive operations if this is a tagged type.
1899 -- Determine whether an arbitrary entity is subject to Boolean aspect
1900 -- Import and its value is specified as True.
1903 -- Following AI05-151, a function can return a limited view of a type
1904 -- declared elsewhere. In that case the function cannot be frozen at
1905 -- the end of its enclosing package. If its first use is in a different
1906 -- unit, it cannot be frozen there, but if the call is legal the full
1907 -- view of the return type is available and the subprogram can now be
1908 -- frozen. However the freeze node cannot be inserted at the point of
1909 -- call, but rather must go in the package holding the function, so that
1910 -- the backend can process it in the proper context.
1913 -- If E is an entity for an imported subprogram with pre/post-conditions
1914 -- then this procedure will create a wrapper to ensure that proper run-
1915 -- time checking of the pre/postconditions. See body for details.
1917 -------------------
1918 -- Add_To_Result --
1919 -------------------
1922 begin
1925 else
1930 ----------------------------
1931 -- After_Last_Declaration --
1932 ----------------------------
1937 begin
1943 else
1947 else
1952 ----------------------------
1953 -- Check_Current_Instance --
1954 ----------------------------
1959 -- Determine whether Typ is compatible with the rules for aliased
1960 -- views of types as defined in RM 3.10 in the various dialects.
1963 -- Process routine to apply check to given node
1965 -----------------------------
1966 -- Is_Aliased_View_Of_Type --
1967 -----------------------------
1972 begin
1973 -- Common case
1977 then
1980 -- The following paragraphs describe what a legal aliased view of
1981 -- a type is in the various dialects of Ada.
1983 -- Ada 95
1985 -- The current instance of a limited type, and a formal parameter
1986 -- or generic formal object of a tagged type.
1988 -- Ada 95 limited type
1989 -- * Type with reserved word "limited"
1990 -- * A protected or task type
1991 -- * A composite type with limited component
1996 -- Ada 2005
1998 -- The current instance of a limited tagged type, a protected
1999 -- type, a task type, or a type that has the reserved word
2000 -- "limited" in its full definition ... a formal parameter or
2001 -- generic formal object of a tagged type.
2003 -- Ada 2005 limited type
2004 -- * Type with reserved word "limited", "synchronized", "task"
2005 -- or "protected"
2006 -- * A composite type with limited component
2007 -- * A derived type whose parent is a non-interface limited type
2010 return
2012 or else
2017 -- Ada 2012 and beyond
2019 -- The current instance of an immutably limited type ... a formal
2020 -- parameter or generic formal object of a tagged type.
2022 -- Ada 2012 limited type
2023 -- * Type with reserved word "limited", "synchronized", "task"
2024 -- or "protected"
2025 -- * A composite type with limited component
2026 -- * A derived type whose parent is a non-interface limited type
2027 -- * An incomplete view
2029 -- Ada 2012 immutably limited type
2030 -- * Explicitly limited record type
2031 -- * Record extension with "limited" present
2032 -- * Non-formal limited private type that is either tagged
2033 -- or has at least one access discriminant with a default
2034 -- expression
2035 -- * Task type, protected type or synchronized interface
2036 -- * Type derived from immutably limited type
2038 else
2039 return
2045 -------------
2046 -- Process --
2047 -------------
2050 begin
2054 Name_Unchecked_Access)
2058 then
2060 Error_Msg_N
2063 else
2064 Error_Msg_N
2071 else
2081 -- Local variables
2086 -- Start of processing for Check_Current_Instance
2088 begin
2094 ------------------------------
2095 -- Check_Suspicious_Modulus --
2096 ------------------------------
2101 begin
2107 declare
2110 begin
2112 declare
2116 begin
2118 declare
2122 begin
2123 -- First case, modulus and size are the same. This
2124 -- happens if you have something like mod 32, with
2125 -- an explicit size of 32, this is for sure a case
2126 -- where the warning is given, since it is seems
2127 -- very unlikely that someone would want e.g. a
2128 -- five bit type stored in 32 bits. It is much
2129 -- more likely they wanted a 32-bit type.
2134 -- Second case, the modulus is 32 or 64 and no
2135 -- size clause is present. This is a less clear
2136 -- case for giving the warning, but in the case
2137 -- of 32/64 (5-bit or 6-bit types) these seem rare
2138 -- enough that it is a likely error (and in any
2139 -- case using 2**5 or 2**6 in these cases seems
2140 -- clearer. We don't include 8 or 16 here, simply
2141 -- because in practice 3-bit and 4-bit types are
2142 -- more common and too many false positives if
2143 -- we warn in these cases.
2147 then
2150 -- No warning needed
2152 else
2156 -- If we fall through, give warning
2159 Error_Msg_N
2161 Modulus);
2170 -----------------------
2171 -- Freeze_Array_Type --
2172 -----------------------
2180 -- Set true if any of the index types is an enumeration type with a
2181 -- non-standard representation.
2183 begin
2192 then
2199 -- Processing that is done only for base types
2203 -- Deal with default setting of reverse storage order
2207 -- Propagate flags for component type
2211 then
2219 -- Warn for pragma Pack overriding foreign convention
2223 then
2224 declare
2229 begin
2233 Error_Msg_N
2236 Error_Msg_N
2243 -- If packing was requested or if the component size was
2244 -- set explicitly, then see if bit packing is required. This
2245 -- processing is only done for base types, since all of the
2246 -- representation aspects involved are type-related.
2248 -- This is not just an optimization, if we start processing the
2249 -- subtypes, they interfere with the settings on the base type
2250 -- (this is because Is_Packed has a slightly different meaning
2251 -- before and after freezing).
2253 declare
2257 begin
2261 then
2270 else
2273 -- We can set the component size if it is less than 16,
2274 -- rounding it up to the next storage unit size.
2280 else
2284 -- Set component size up to match alignment if it would
2285 -- otherwise be less than the alignment. This deals with
2286 -- cases of types whose alignment exceeds their size (the
2287 -- padded type cases).
2290 declare
2292 begin
2300 -- Case of component size that may result in packing
2303 declare
2309 Get_Attribute_Definition_Clause
2312 begin
2313 -- Warn if we have pack and component size so that the
2314 -- pack is ignored.
2316 -- Note: here we must check for the presence of a
2317 -- component size before checking for a Pack pragma to
2318 -- deal with the case where the array type is a derived
2319 -- type whose parent is currently private.
2323 and then Warn_On_Redundant_Constructs
2324 then
2326 Error_Msg_NE
2328 Error_Msg_N
2334 -- Set component size if not already set by a component
2335 -- size clause.
2341 -- Check for base type of 8, 16, 32 bits, where an
2342 -- unsigned subtype has a length one less than the
2343 -- base type (e.g. Natural subtype of Integer).
2345 -- In such cases, if a component size was not set
2346 -- explicitly, then generate a warning.
2352 then
2356 Error_Msg_N
2358 Pack_Pragma);
2359 Error_Msg_N
2361 Pack_Pragma);
2365 -- Actual packing is not needed for 8, 16, 32, 64. Also
2366 -- not needed for 24 if alignment is 1.
2373 then
2374 -- Here the array was requested to be packed, but
2375 -- the packing request had no effect, so Is_Packed
2376 -- is reset.
2378 -- Note: semantically this means that we lose track
2379 -- of the fact that a derived type inherited a pragma
2380 -- Pack that was non- effective, but that seems fine.
2382 -- We regard a Pack pragma as a request to set a
2383 -- representation characteristic, and this request
2384 -- may be ignored.
2391 then
2395 -- In all other cases, packing is indeed needed
2397 else
2406 -- Check for Atomic_Components or Aliased with unsuitable packing
2407 -- or explicit component size clause given.
2410 or else
2412 and then
2414 then
2418 -- Outputs error messages for incorrect CS clause or pragma
2419 -- Pack for aliased or atomic components (T is "aliased" or
2420 -- "atomic");
2422 -----------------
2423 -- Complain_CS --
2424 -----------------
2427 begin
2429 Clause :=
2430 Get_Attribute_Definition_Clause
2434 Error_Msg_N
2438 Error_Msg_N
2441 else
2442 Error_Msg_N
2447 else
2448 Error_Msg_N
2456 -- Start of processing for Alias_Atomic_Check
2458 begin
2459 -- If object size of component type isn't known, we cannot
2460 -- be sure so we defer to the back end.
2465 -- Case where component size has no effect. First check for
2466 -- object size of component type multiple of the storage
2467 -- unit size.
2471 -- OK in both packing case and component size case if RM
2472 -- size is known and static and same as the object size.
2474 and then
2478 -- Or if we have an explicit component size clause and
2479 -- the component size and object size are equal.
2481 or else
2484 then
2489 then
2494 then
2500 -- Warn for case of atomic type
2506 then
2507 Error_Msg_NE
2522 -- Check for scalar storage order
2524 declare
2526 begin
2527 Check_Component_Storage_Order
2530 ADC => Get_Attribute_Definition_Clause
2532 Attribute_Scalar_Storage_Order),
2536 -- Processing that is done only for subtypes
2538 else
2539 -- Acquire alignment from base type
2547 -- Specific checks for bit-packed arrays
2551 -- Check number of elements for bit packed arrays that come from
2552 -- source and have compile time known ranges. The bit-packed
2553 -- arrays circuitry does not support arrays with more than
2554 -- Integer'Last + 1 elements, and when this restriction is
2555 -- violated, causes incorrect data access.
2557 -- For the case where this is not compile time known, a run-time
2558 -- check should be generated???
2561 declare
2567 begin
2573 -- Never generate an error if any index is of a generic
2574 -- type. We will check this in instances.
2581 Ilen :=
2587 -- No attempt is made to check number of elements if not
2588 -- compile time known.
2601 then
2602 Error_Msg_N
2609 -- Check size
2612 declare
2616 begin
2617 -- It is not clear if it is possible to have no size clause
2618 -- at this stage, but it is not worth worrying about. Post
2619 -- error on the entity name in the size clause if present,
2620 -- else on the type entity itself.
2624 else
2631 -- If any of the index types was an enumeration type with a non-
2632 -- standard rep clause, then we indicate that the array type is
2633 -- always packed (even if it is not bit packed).
2642 -- If the array is packed, we must create the packed array type to be
2643 -- used to actually implement the type. This is only needed for real
2644 -- array types (not for string literal types, since they are present
2645 -- only for the front end).
2649 then
2653 -- Make sure that we have the necessary routines to implement the
2654 -- packing, and complain now if not. Note that we only test this
2655 -- for constrained array types.
2661 then
2662 declare
2666 begin
2669 then
2670 Error_Msg_CRT
2674 -- Cancel the packing
2684 -- Size information of packed array type is copied to the array
2685 -- type, since this is really the representation. But do not
2686 -- override explicit existing size values. If the ancestor subtype
2687 -- is constrained the Packed_Array_Impl_Type will be inherited
2688 -- from it, but the size may have been provided already, and
2689 -- must not be overridden either.
2692 and then
2695 then
2707 -- For non-packed arrays set the alignment of the array to the
2708 -- alignment of the component type if it is unknown. Skip this
2709 -- in atomic case (atomic arrays may need larger alignments).
2718 then
2723 -----------------------------
2724 -- Freeze_Generic_Entities --
2725 -----------------------------
2732 begin
2751 --------------------
2752 -- Freeze_Profile --
2753 --------------------
2760 begin
2761 -- Loop through formals
2767 -- AI05-0151: incomplete types can appear in a profile. By the
2768 -- time the entity is frozen, the full view must be available,
2769 -- unless it is a limited view.
2774 then
2786 then
2787 -- If the type of a formal is incomplete, subprogram is being
2788 -- frozen prematurely. Within an instance (but not within a
2789 -- wrapper package) this is an artifact of our need to regard
2790 -- the end of an instantiation as a freeze point. Otherwise it
2791 -- is a definite error.
2798 elsif not After_Last_Declaration
2799 and then not Freezing_Library_Level_Tagged_Type
2800 then
2802 Error_Msg
2807 -- Check suspicious parameter for C function. These tests apply
2808 -- only to exported/imported subprograms.
2810 if Warn_On_Export_Import
2813 or else
2820 then
2821 -- Qualify mention of formals with subprogram name
2825 -- Check suspicious use of fat C pointer
2829 then
2830 Error_Msg_N
2833 -- Check suspicious return of boolean
2840 then
2841 Error_Msg_N
2843 Error_Msg_N
2847 -- Check suspicious tagged type
2850 or else
2854 then
2855 Error_Msg_N
2859 -- Check wrong convention subprogram pointer
2863 then
2864 Error_Msg_N
2868 Error_Msg_NE
2873 -- Turn off name qualification after message output
2878 -- Check for unconstrained array in exported foreign convention
2879 -- case.
2885 and then Warn_On_Export_Import
2887 -- Exclude VM case, since both .NET and JVM can handle
2888 -- unconstrained arrays without a problem.
2891 then
2894 -- If this is an inherited operation, place the warning on
2895 -- the derived type declaration, rather than on the original
2896 -- subprogram.
2899 then
2905 else
2921 -- If the formal is an anonymous_access_to_subprogram
2922 -- freeze the subprogram type as well, to prevent
2923 -- scope anomalies in gigi, because there is no other
2924 -- clear point at which it could be frozen.
2928 then
2936 -- Case of function: similar checks on return type
2940 -- Check whether function is declared elsewhere.
2942 Late_Freezing :=
2947 -- Freeze return type
2951 -- AI05-0151: the return type may have been incomplete
2952 -- at the point of declaration. Replace it with the full
2953 -- view, unless the current type is a limited view. In
2954 -- that case the full view is in a different unit, and
2955 -- gigi finds the non-limited view after the other unit
2956 -- is elaborated.
2961 then
2965 -- If the return type is a limited view and the non-
2966 -- limited view is still incomplete, the function has
2967 -- to be frozen at a later time.
2971 and then
2973 then
2981 -- Check suspicious return type for C function
2983 if Warn_On_Export_Import
2985 or else
2988 then
2989 -- Check suspicious return of fat C pointer
2995 then
2999 -- Check suspicious return of boolean
3007 then
3008 declare
3011 begin
3012 Error_Msg_NE
3014 Error_Msg_NE
3019 -- Check suspicious return tagged type
3023 and then
3024 Is_Tagged_Type
3029 then
3033 -- Check return of wrong convention subprogram pointer
3039 then
3043 Error_Msg_NE
3049 -- Give warning for suspicious return of a result of an
3050 -- unconstrained array type in a foreign convention function.
3054 -- We are looking for a return of unconstrained array
3059 -- Exclude imported routines, the warning does not belong on
3060 -- the import, but rather on the routine definition.
3064 -- Exclude VM case, since both .NET and JVM can handle return
3065 -- of unconstrained arrays without a problem.
3069 -- Check that general warning is enabled, and that it is not
3070 -- suppressed for this particular case.
3072 and then Warn_On_Export_Import
3075 then
3084 ------------------------
3085 -- Freeze_Record_Type --
3086 ------------------------
3098 -- Set True if the record type scope Rec has been pushed on the scope
3099 -- stack. Needed for the analysis of delayed aspects specified to the
3100 -- components of Rec.
3103 -- Scalar_Storage_Order attribute definition clause for the record
3106 -- Set True if we find at least one component with no component
3107 -- clause (used to warn about useless Pack pragmas).
3110 -- Set True if we find at least one component with a component
3111 -- clause (used to warn about useless Bit_Order pragmas, and also
3112 -- to detect cases where Implicit_Packing may have an effect).
3115 -- Set True if we find at least one component which is aliased. This
3116 -- is used to prevent Implicit_Packing of the record, since packing
3117 -- cannot modify the size of alignment of an aliased component.
3120 -- Set True if we find at least one component whose type has a
3121 -- Scalar_Storage_Order attribute definition clause.
3124 -- Set False if we encounter a component of a non-scalar type
3128 -- Accumulates total RM_Size values and total Esize values of all
3129 -- scalar components. Used for processing of Implicit_Packing.
3132 -- If N is an allocator, possibly wrapped in one or more level of
3133 -- qualified expression(s), return the inner allocator node, else
3134 -- return Empty.
3137 -- If the component subtype is an access to a constrained subtype of
3138 -- an already frozen type, make the subtype frozen as well. It might
3139 -- otherwise be frozen in the wrong scope, and a freeze node on
3140 -- subtype has no effect. Similarly, if the component subtype is a
3141 -- regular (not protected) access to subprogram, set the anonymous
3142 -- subprogram type to frozen as well, to prevent an out-of-scope
3143 -- freeze node at some eventual point of call. Protected operations
3144 -- are handled elsewhere.
3147 -- Make sure that all types mentioned in Discrete_Choices of the
3148 -- variants referenceed by the Variant_Part VP are frozen. This is
3149 -- a recursive routine to deal with nested variants.
3151 ---------------------
3152 -- Check_Allocator --
3153 ---------------------
3157 begin
3159 loop
3164 else
3170 -----------------
3171 -- Check_Itype --
3172 -----------------
3177 begin
3180 then
3183 -- In addition, add an Itype_Reference to ensure that the
3184 -- access subtype is elaborated early enough. This cannot be
3185 -- done if the subtype may depend on discriminants.
3190 then
3198 then
3203 ------------------------------------
3204 -- Freeze_Choices_In_Variant_Part --
3205 ------------------------------------
3214 begin
3215 -- Loop through variants
3220 -- Loop through choices, checking that all types are frozen
3226 then
3233 -- Check for nested variant part to process
3247 -- Start of processing for Freeze_Record_Type
3249 begin
3250 -- Deal with delayed aspect specifications for components. The
3251 -- analysis of the aspect is required to be delayed to the freeze
3252 -- point, thus we analyze the pragma or attribute definition
3253 -- clause in the tree at this point. We also analyze the aspect
3254 -- specification node at the freeze point when the aspect doesn't
3255 -- correspond to pragma/attribute definition clause.
3261 then
3266 -- The visibility to the discriminants must be restored in
3267 -- order to properly analyze the aspects.
3280 -- Pop the scope if Rec scope has been pushed on the scope stack
3281 -- during the delayed aspect analysis process.
3288 Pop_Scope;
3291 -- Freeze components and embedded subtypes
3300 -- Handle the component and discriminant case
3303 declare
3306 begin
3307 -- Freezing a record type freezes the type of each of its
3308 -- components. However, if the type of the component is
3309 -- part of this record, we do not want or need a separate
3310 -- Freeze_Node. Note that Is_Itype is wrong because that's
3311 -- also set in private type cases. We also can't check for
3312 -- the Scope being exactly Rec because of private types and
3313 -- record extensions.
3318 then
3324 -- Warn for pragma Pack overriding foreign convention
3329 -- Don't warn for aliased components, since override
3330 -- cannot happen in that case.
3333 then
3334 declare
3339 begin
3343 Error_Msg_N
3345 PP);
3347 Error_Msg_NE
3354 -- Check for error of component clause given for variable
3355 -- sized type. We have to delay this test till this point,
3356 -- since the component type has to be frozen for us to know
3357 -- if it is variable length.
3362 -- We omit this test in a generic context, it will be
3363 -- applied at instantiation time.
3368 -- Also omit this test in CodePeer mode, since we do not
3369 -- have sufficient info on size and rep clauses.
3374 -- Omit check if component has a generic type. This can
3375 -- happen in an instantiation within a generic in ASIS
3376 -- mode, where we force freeze actions without full
3377 -- expansion.
3382 -- Do the check
3384 elsif not
3385 Size_Known_At_Compile_Time
3387 then
3388 Error_Msg_N
3393 else
3397 -- Case of component requires byte alignment
3401 -- Set the enclosing record to also require byte align
3405 -- Check for component clause that is inconsistent with
3406 -- the required byte boundary alignment.
3411 then
3412 Error_Msg_N
3420 -- Gather data for possible Implicit_Packing later. Note that at
3421 -- this stage we might be dealing with a real component, or with
3422 -- an implicit subtype declaration.
3426 else
3427 Scalar_Component_Total_RM_Size :=
3429 Scalar_Component_Total_Esize :=
3433 -- If the component is an Itype with Delayed_Freeze and is either
3434 -- a record or array subtype and its base type has not yet been
3435 -- frozen, we must remove this from the entity list of this record
3436 -- and put it on the entity list of the scope of its base type.
3437 -- Note that we know that this is not the type of a component
3438 -- since we cleared Has_Delayed_Freeze for it in the previous
3439 -- loop. Thus this must be the Designated_Type of an access type,
3440 -- which is the type of a component.
3448 then
3449 declare
3453 begin
3454 -- We have a difficult case to handle here. Suppose Rec is
3455 -- subtype being defined in a subprogram that's created as
3456 -- part of the freezing of Rec'Base. In that case, we know
3457 -- that Comp'Base must have already been frozen by the time
3458 -- we get to elaborate this because Gigi doesn't elaborate
3459 -- any bodies until it has elaborated all of the declarative
3460 -- part. But Is_Frozen will not be set at this point because
3461 -- we are processing code in lexical order.
3463 -- We detect this case by going up the Scope chain of Rec
3464 -- and seeing if we have a subprogram scope before reaching
3465 -- the top of the scope chain or that of Comp'Base. If we
3466 -- do, then mark that Comp'Base will actually be frozen. If
3467 -- so, we merely undelay it.
3484 else
3487 else
3491 -- Insert in entity list of scope of base type (which
3492 -- must be an enclosing scope, because still unfrozen).
3498 -- If the component is an access type with an allocator as default
3499 -- value, the designated type will be frozen by the corresponding
3500 -- expression in init_proc. In order to place the freeze node for
3501 -- the designated type before that for the current record type,
3502 -- freeze it now.
3504 -- Same process if the component is an array of access types,
3505 -- initialized with an aggregate. If the designated type is
3506 -- private, it cannot contain allocators, and it is premature
3507 -- to freeze the type, so we check for this as well.
3512 then
3513 declare
3517 begin
3520 -- If component is pointer to a class-wide type, freeze
3521 -- the specific type in the expression being allocated.
3522 -- The expression may be a subtype indication, in which
3523 -- case freeze the subtype mark.
3525 if Is_Class_Wide_Type
3527 then
3529 Freeze_And_Append
3533 then
3534 Freeze_And_Append
3542 else
3543 Freeze_And_Append
3551 then
3554 -- Freeze the designated type when initializing a component with
3555 -- an aggregate in case the aggregate contains allocators.
3557 -- type T is ...;
3558 -- type T_Ptr is access all T;
3559 -- type T_Array is array ... of T_Ptr;
3561 -- type Rec is record
3562 -- Comp : T_Array := (others => ...);
3563 -- end record;
3567 then
3568 declare
3571 Designated_Type
3574 begin
3575 -- The only case when this sort of freezing is not done is
3576 -- when the designated type is class-wide and the root type
3577 -- is the record owning the component. This scenario results
3578 -- in a circularity because the class-wide type requires
3579 -- primitives that have not been created yet as the root
3580 -- type is in the process of being frozen.
3582 -- type Rec is tagged;
3583 -- type Rec_Ptr is access all Rec'Class;
3584 -- type Rec_Array is array ... of Rec_Ptr;
3586 -- type Rec is record
3587 -- Comp : Rec_Array := (others => ...);
3588 -- end record;
3592 then
3600 then
3610 -- Deal with default setting of reverse storage order
3614 -- Check consistent attribute setting on component types
3616 SSO_ADC := Get_Attribute_Definition_Clause
3619 declare
3621 begin
3624 Check_Component_Storage_Order
3634 -- Now deal with reverse storage order/bit order issues
3638 -- Check compatibility of Scalar_Storage_Order with Bit_Order, if
3639 -- the former is specified.
3643 -- Note: report error on Rec, not on SSO_ADC, as ADC may apply
3644 -- to some ancestor type.
3647 Error_Msg_N
3652 -- Warn if there is an Scalar_Storage_Order attribute definition
3653 -- clause but no component clause, no component that itself has
3654 -- such an attribute definition, and no pragma Pack.
3657 or else
3658 SSO_ADC_Component
3659 or else
3661 then
3662 Error_Msg_N
3664 SSO_ADC);
3668 -- Deal with Bit_Order aspect
3676 then
3677 -- Warn if clause has no effect when no component clause is
3678 -- present, but suppress warning if the Bit_Order is required
3679 -- due to the presence of a Scalar_Storage_Order attribute.
3681 Error_Msg_N
3683 Error_Msg_N
3686 -- Here is where we do the processing to adjust component clauses
3687 -- for reversed bit order, when not using reverse SSO.
3691 then
3694 -- Case where we have both an explicit Bit_Order and the same
3695 -- Scalar_Storage_Order: leave record untouched, the back-end
3696 -- will take care of required layout conversions.
3698 else
3704 -- Complete error checking on record representation clause (e.g.
3705 -- overlap of components). This is called after adjusting the
3706 -- record for reverse bit order.
3708 declare
3710 begin
3716 -- Set OK_To_Reorder_Components depending on debug flags
3720 or else
3722 then
3727 -- Check for useless pragma Pack when all components placed. We only
3728 -- do this check for record types, not subtypes, since a subtype may
3729 -- have all its components placed, and it still makes perfectly good
3730 -- sense to pack other subtypes or the parent type. We do not give
3731 -- this warning if Optimize_Alignment is set to Space, since the
3732 -- pragma Pack does have an effect in this case (it always resets
3733 -- the alignment to one).
3737 and then not Unplaced_Component
3739 then
3740 -- Reset packed status. Probably not necessary, but we do it so
3741 -- that there is no chance of the back end doing something strange
3742 -- with this redundant indication of packing.
3746 -- Give warning if redundant constructs warnings on
3749 Error_Msg_N -- CODEFIX
3755 -- If this is the record corresponding to a remote type, freeze the
3756 -- remote type here since that is what we are semantically freezing.
3757 -- This prevents the freeze node for that type in an inner scope.
3764 -- Check for controlled components and unchecked unions.
3769 -- Do not set Has_Controlled_Component on a class-wide
3770 -- equivalent type. See Make_CW_Equivalent_Type.
3773 and then
3775 or else
3778 or else
3780 and then
3782 and then
3783 Has_Controlled_Component
3785 then
3793 -- Scan component declaration for likely misuses of current
3794 -- instance, either in a constraint or a default expression.
3804 -- Enforce the restriction that access attributes with a current
3805 -- instance prefix can only apply to limited types. This comment
3806 -- is floating here, but does not seem to belong here???
3808 -- Set component alignment if not otherwise already set
3812 -- For first subtypes, check if there are any fixed-point fields with
3813 -- component clauses, where we must check the size. This is not done
3814 -- till the freeze point since for fixed-point types, we do not know
3815 -- the size until the type is frozen. Similar processing applies to
3816 -- bit packed arrays.
3824 then
3825 Check_Size
3829 Junk);
3836 -- Generate warning for applying C or C++ convention to a record
3837 -- with discriminants. This is suppressed for the unchecked union
3838 -- case, since the whole point in this case is interface C. We also
3839 -- do not generate this within instantiations, since we will have
3840 -- generated a message on the template.
3845 or else
3848 and then not In_Instance
3851 then
3852 declare
3856 begin
3861 Error_Msg_N
3863 A2);
3864 else
3865 Error_Msg_N
3867 A2);
3870 Error_Msg_NE
3876 -- See if Size is too small as is (and implicit packing might help)
3880 -- No implicit packing if even one component is explicitly placed
3882 and then not Placed_Component
3884 -- Or even one component is aliased
3886 and then not Aliased_Component
3888 -- Must have size clause and all scalar components
3891 and then All_Scalar_Components
3893 -- Do not try implicit packing on records with discriminants, too
3894 -- complicated, especially in the variant record case.
3898 -- We can implicitly pack if the specified size of the record is
3899 -- less than the sum of the object sizes (no point in packing if
3900 -- this is not the case).
3904 -- And the total RM size cannot be greater than the specified size
3905 -- since otherwise packing will not get us where we have to be.
3909 -- Never do implicit packing in CodePeer or SPARK modes since
3910 -- we don't do any packing in these modes, since this generates
3911 -- over-complex code that confuses static analysis, and in
3912 -- general, neither CodePeer not GNATprove care about the
3913 -- internal representation of objects.
3916 then
3917 -- If implicit packing enabled, do it
3922 -- Otherwise flag the size clause
3924 else
3925 declare
3927 begin
3928 Error_Msg_NE -- CODEFIX
3930 Error_Msg_N -- CODEFIX
3937 -- The following checks are only relevant when SPARK_Mode is on as
3938 -- they are not standard Ada legality rules.
3943 -- A discriminated type cannot be effectively volatile
3944 -- (SPARK RM C.6(4)).
3949 -- A tagged type cannot be effectively volatile
3950 -- (SPARK RM C.6(5)).
3956 -- A non-effectively volatile record type cannot contain
3957 -- effectively volatile components (SPARK RM C.6(2)).
3959 else
3964 then
3966 Error_Msg_N
3976 -- All done if not a full record definition
3982 -- Finally we need to check the variant part to make sure that
3983 -- all types within choices are properly frozen as part of the
3984 -- freezing of the record type.
3991 begin
3992 -- Find component list
4004 then
4009 -- Case of variant part present
4015 -- Note: we used to call Check_Choices here, but it is too early,
4016 -- since predicated subtypes are frozen here, but their freezing
4017 -- actions are in Analyze_Freeze_Entity, which has not been called
4018 -- yet for entities frozen within this procedure, so we moved that
4019 -- call to the Analyze_Freeze_Entity for the record type.
4023 -- Check that all the primitives of an interface type are abstract
4024 -- or null procedures.
4028 then
4029 declare
4033 begin
4040 -- Avoid reporting the error on inherited primitives
4043 then
4048 Error_Msg_N
4052 else
4053 Error_Msg_N
4065 -------------------------------
4066 -- Has_Boolean_Aspect_Import --
4067 -------------------------------
4074 begin
4080 -- The value of aspect Import is True when the expression is
4081 -- either missing or it is explicitly set to True.
4087 then
4098 ----------------------------
4099 -- Late_Freeze_Subprogram --
4100 ----------------------------
4107 begin
4110 else
4117 ------------------------------
4118 -- Wrap_Imported_Subprogram --
4119 ------------------------------
4121 -- The issue here is that our normal approach of checking preconditions
4122 -- and postconditions does not work for imported procedures, since we
4123 -- are not generating code for the body. To get around this we create
4124 -- a wrapper, as shown by the following example:
4126 -- procedure K (A : Integer);
4127 -- pragma Import (C, K);
4129 -- The spec is rewritten by removing the effects of pragma Import, but
4130 -- leaving the convention unchanged, as though the source had said:
4132 -- procedure K (A : Integer);
4133 -- pragma Convention (C, K);
4135 -- and we create a body, added to the entity K freeze actions, which
4136 -- looks like:
4138 -- procedure K (A : Integer) is
4139 -- procedure K (A : Integer);
4140 -- pragma Import (C, K);
4141 -- begin
4142 -- K (A);
4143 -- end K;
4145 -- Now the contract applies in the normal way to the outer procedure,
4146 -- and the inner procedure has no contracts, so there is no problem
4147 -- in just calling it to get the original effect.
4149 -- In the case of a function, we create an appropriate return statement
4150 -- for the subprogram body that calls the inner procedure.
4162 begin
4163 -- Nothing to do if not imported
4168 -- Test enabling conditions for wrapping
4173 and then not GNATprove_Mode
4174 then
4175 -- Here we do the wrap
4177 -- Note on calls to Copy_Separate_Tree. The trees we are copying
4178 -- here are fully analyzed, but we definitely want fully syntactic
4179 -- unanalyzed trees in the body we construct, so that the analysis
4180 -- generates the right visibility, and that is exactly what the
4181 -- calls to Copy_Separate_Tree give us.
4183 -- Acquire copy of Inline pragma
4187 -- Fix up spec to be not imported any more
4194 -- Grab the subprogram declaration and specification
4198 -- Build parameter list that we need
4207 -- Build the call
4210 Stmt :=
4212 Expression =>
4217 else
4218 Stmt :=
4224 -- Now build the body
4226 Bod :=
4228 Specification =>
4232 Specification =>
4234 Iprag),
4235 Handled_Statement_Sequence =>
4240 -- Append the body to freeze result
4245 -- Case of imported subprogram that does not get wrapped
4247 else
4248 -- Set Is_Public. All imported entities need an external symbol
4249 -- created for them since they are always referenced from another
4250 -- object file. Note this used to be set when we set Is_Imported
4251 -- back in Sem_Prag, but now we delay it to this point, since we
4252 -- don't want to set this flag if we wrap an imported subprogram.
4258 -- Start of processing for Freeze_Entity
4260 begin
4261 -- We are going to test for various reasons why this entity need not be
4262 -- frozen here, but in the case of an Itype that's defined within a
4263 -- record, that test actually applies to the record.
4269 then
4273 -- Do not freeze if already frozen since we only need one freeze node
4278 -- It is improper to freeze an external entity within a generic because
4279 -- its freeze node will appear in a non-valid context. The entity will
4280 -- be frozen in the proper scope after the current generic is analyzed.
4281 -- However, aspects must be analyzed because they may be queried later
4282 -- within the generic itself, and the corresponding pragma or attribute
4283 -- definition has not been analyzed yet.
4292 -- AI05-0213: A formal incomplete type does not freeze the actual. In
4293 -- the instance, the same applies to the subtype renaming the actual.
4299 then
4302 -- Formal subprograms are never frozen
4307 -- Generic types are never frozen as they lack delayed semantic checks
4312 -- Do not freeze a global entity within an inner scope created during
4313 -- expansion. A call to subprogram E within some internal procedure
4314 -- (a stream attribute for example) might require freezing E, but the
4315 -- freeze node must appear in the same declarative part as E itself.
4316 -- The two-pass elaboration mechanism in gigi guarantees that E will
4317 -- be frozen before the inner call is elaborated. We exclude constants
4318 -- from this test, because deferred constants may be frozen early, and
4319 -- must be diagnosed (e.g. in the case of a deferred constant being used
4320 -- in a default expression). If the enclosing subprogram comes from
4321 -- source, or is a generic instance, then the freeze point is the one
4322 -- mandated by the language, and we freeze the entity. A subprogram that
4323 -- is a child unit body that acts as a spec does not have a spec that
4324 -- comes from source, but can only come from source.
4329 then
4330 declare
4333 begin
4340 then
4342 else
4351 -- Similarly, an inlined instance body may make reference to global
4352 -- entities, but these references cannot be the proper freezing point
4353 -- for them, and in the absence of inlining freezing will take place in
4354 -- their own scope. Normally instance bodies are analyzed after the
4355 -- enclosing compilation, and everything has been frozen at the proper
4356 -- place, but with front-end inlining an instance body is compiled
4357 -- before the end of the enclosing scope, and as a result out-of-order
4358 -- freezing must be prevented.
4360 elsif Front_End_Inlining
4361 and then In_Instance_Body
4363 then
4364 declare
4367 begin
4372 else
4386 -- Add checks to detect proper initialization of scalars that may appear
4387 -- as subprogram parameters.
4393 -- Deal with delayed aspect specifications. The analysis of the aspect
4394 -- is required to be delayed to the freeze point, thus we analyze the
4395 -- pragma or attribute definition clause in the tree at this point. We
4396 -- also analyze the aspect specification node at the freeze point when
4397 -- the aspect doesn't correspond to pragma/attribute definition clause.
4403 -- Here to freeze the entity
4407 -- Case of entity being frozen is other than a type
4411 -- If entity is exported or imported and does not have an external
4412 -- name, now is the time to provide the appropriate default name.
4413 -- Skip this if the entity is stubbed, since we don't need a name
4414 -- for any stubbed routine. For the case on intrinsics, if no
4415 -- external name is specified, then calls will be handled in
4416 -- Exp_Intr.Expand_Intrinsic_Call, and no name is needed. If an
4417 -- external name is provided, then Expand_Intrinsic_Call leaves
4418 -- calls in place for expansion by GIGI.
4424 then
4425 Set_Encoded_Interface_Name
4428 -- If entity is an atomic object appearing in a declaration and
4429 -- the expression is an aggregate, assign it to a temporary to
4430 -- ensure that the actual assignment is done atomically rather
4431 -- than component-wise (the assignment to the temp may be done
4432 -- component-wise, but that is harmless).
4439 then
4443 -- Subprogram case
4447 -- Check for needing to wrap imported subprogram
4451 -- Freeze all parameter types and the return type (RM 13.14(14)).
4452 -- However skip this for internal subprograms. This is also where
4453 -- any extra formal parameters are created since we now know
4454 -- whether the subprogram will use a foreign convention.
4456 -- In Ada 2012, freezing a subprogram does not always freeze
4457 -- the corresponding profile (see AI05-019). An attribute
4458 -- reference is not a freezing point of the profile.
4459 -- Other constructs that should not freeze ???
4461 -- This processing doesn't apply to internal entities (see below)
4469 -- Must freeze its parent first if it is a derived subprogram
4475 -- We don't freeze internal subprograms, because we don't normally
4476 -- want addition of extra formals or mechanism setting to happen
4477 -- for those. However we do pass through predefined dispatching
4478 -- cases, since extra formals may be needed in some cases, such as
4479 -- for the stream 'Input function (build-in-place formals).
4483 then
4492 -- If warning on suspicious contracts then check for the case of
4493 -- a postcondition other than False for a No_Return subprogram.
4496 and then Warn_On_Suspicious_Contract
4498 then
4499 declare
4503 begin
4506 Name_Postcondition,
4507 Name_Refined_Post)
4508 then
4509 Exp :=
4510 Expression
4515 then
4516 Error_Msg_NE
4527 -- Here for other than a subprogram or type
4529 else
4530 -- If entity has a type, and it is not a generic unit, then
4531 -- freeze it first (RM 13.14(10)).
4535 then
4538 -- For an object of an anonymous array type, aspects on the
4539 -- object declaration apply to the type itself. This is the
4540 -- case for Atomic_Components, Volatile_Components, and
4541 -- Independent_Components. In these cases analysis of the
4542 -- generated pragma will mark the anonymous types accordingly,
4543 -- and the object itself does not require a freeze node.
4549 then
4556 -- Special processing for objects created by object declaration
4560 -- Abstract type allowed only for C++ imported variables or
4561 -- constants.
4563 -- Note: we inhibit this check for objects that do not come
4564 -- from source because there is at least one case (the
4565 -- expansion of x'Class'Input where x is abstract) where we
4566 -- legitimately generate an abstract object.
4572 then
4577 Error_Msg_NE
4582 Error_Msg_N -- CODEFIX
4588 -- For object created by object declaration, perform required
4589 -- categorization (preelaborate and pure) checks. Defer these
4590 -- checks to freeze time since pragma Import inhibits default
4591 -- initialization and thus pragma Import affects these checks.
4595 -- If there is an address clause, check that it is valid
4599 -- Reset Is_True_Constant for aliased object. We consider that
4600 -- the fact that something is aliased may indicate that some
4601 -- funny business is going on, e.g. an aliased object is passed
4602 -- by reference to a procedure which captures the address of
4603 -- the object, which is later used to assign a new value. Such
4604 -- code is highly dubious, but we choose to make it "work" for
4605 -- aliased objects.
4607 -- However, we don't do that for internal entities. We figure
4608 -- that if we deliberately set Is_True_Constant for an internal
4609 -- entity, e.g. a dispatch table entry, then we mean it.
4613 then
4617 -- If the object needs any kind of default initialization, an
4618 -- error must be issued if No_Default_Initialization applies.
4619 -- The check doesn't apply to imported objects, which are not
4620 -- ever default initialized, and is why the check is deferred
4621 -- until freezing, at which point we know if Import applies.
4622 -- Deferred constants are also exempted from this test because
4623 -- their completion is explicit, or through an import pragma.
4627 then
4633 and then
4638 or else
4641 then
4643 Check_Restriction
4647 -- Check that a Thread_Local_Storage variable does not have
4648 -- default initialization, and any explicit initialization must
4649 -- either be the null constant or a static constant.
4652 declare
4654 begin
4655 if Has_Default_Initialization
4656 or else
4658 and then
4660 or else not
4662 or else
4664 then
4665 Error_Msg_NE
4668 Error_Msg_NE
4675 -- For imported objects, set Is_Public unless there is also an
4676 -- address clause, which means that there is no external symbol
4677 -- needed for the Import (Is_Public may still be set for other
4678 -- unrelated reasons). Note that we delayed this processing
4679 -- till freeze time so that we can be sure not to set the flag
4680 -- if there is an address clause. If there is such a clause,
4681 -- then the only purpose of the Import pragma is to suppress
4682 -- implicit initialization.
4688 -- For source objects that are not Imported and are library
4689 -- level, if no linker section pragma was given inherit the
4690 -- appropriate linker section from the corresponding type.
4696 then
4697 Set_Linker_Section_Pragma
4701 -- For convention C objects of an enumeration type, warn if
4702 -- the size is not integer size and no explicit size given.
4703 -- Skip warning for Boolean, and Character, assume programmer
4704 -- expects 8-bit sizes for these cases.
4707 or else
4714 then
4716 Error_Msg_N
4718 E);
4723 -- Check that a constant which has a pragma Volatile[_Components]
4724 -- or Atomic[_Components] also has a pragma Import (RM C.6(13)).
4726 -- Note: Atomic[_Components] also sets Volatile[_Components]
4732 then
4733 -- Make sure we actually have a pragma, and have not merely
4734 -- inherited the indication from elsewhere (e.g. an address
4735 -- clause, which is not good enough in RM terms).
4738 or else
4740 then
4741 Error_Msg_N
4746 or else
4748 then
4749 Error_Msg_N
4755 -- Static objects require special handling
4759 then
4763 -- Remaining step is to layout objects
4767 then
4771 -- For an object that does not have delayed freezing, and whose
4772 -- initialization actions have been captured in a compound
4773 -- statement, move them back now directly within the enclosing
4774 -- statement sequence.
4778 then
4783 -- Case of a type or subtype being frozen
4785 else
4786 -- We used to check here that a full type must have preelaborable
4787 -- initialization if it completes a private type specified with
4788 -- pragma Preelaborable_Initialization, but that missed cases where
4789 -- the types occur within a generic package, since the freezing
4790 -- that occurs within a containing scope generally skips traversal
4791 -- of a generic unit's declarations (those will be frozen within
4792 -- instances). This check was moved to Analyze_Package_Specification.
4794 -- The type may be defined in a generic unit. This can occur when
4795 -- freezing a generic function that returns the type (which is
4796 -- defined in a parent unit). It is clearly meaningless to freeze
4797 -- this type. However, if it is a subtype, its size may be determi-
4798 -- nable and used in subsequent checks, so might as well try to
4799 -- compute it.
4801 -- In Ada 2012, Freeze_Entities is also used in the front end to
4802 -- trigger the analysis of aspect expressions, so in this case we
4803 -- want to continue the freezing process.
4807 and then
4810 then
4815 -- Check for error of Type_Invariant'Class applied to an untagged
4816 -- type (check delayed to freeze time when full type is available).
4818 declare
4820 begin
4824 then
4825 Error_Msg_NE
4828 Error_Msg_N
4833 -- A Ghost type cannot be effectively volatile (SPARK RM 6.9(8))
4837 then
4841 -- Deal with special cases of freezing for subtype
4845 -- Before we do anything else, a specialized test for the case of
4846 -- a size given for an array where the array needs to be packed,
4847 -- but was not so the size cannot be honored. This is the case
4848 -- where implicit packing may apply. The reason we do this so
4849 -- early is that if we have implicit packing, the layout of the
4850 -- base type is affected, so we must do this before we freeze
4851 -- the base type.
4853 -- We could do this processing only if implicit packing is enabled
4854 -- since in all other cases, the error would be caught by the back
4855 -- end. However, we choose to do the check even if we do not have
4856 -- implicit packing enabled, since this allows us to give a more
4857 -- useful error message (advising use of pragmas Implicit_Packing
4858 -- or Pack).
4861 declare
4872 -- Number of elements in array
4874 begin
4875 -- Check enabling conditions. These are straightforward
4876 -- except for the test for a limited composite type. This
4877 -- eliminates the rare case of a array of limited components
4878 -- where there are issues of whether or not we can go ahead
4879 -- and pack the array (since we can't freely pack and unpack
4880 -- arrays if they are limited).
4882 -- Note that we check the root type explicitly because the
4883 -- whole point is we are doing this test before we have had
4884 -- a chance to freeze the base type (and it is that freeze
4885 -- action that causes stuff to be inherited).
4898 then
4899 -- Compute number of elements in array
4907 and then
4909 then
4913 Num_Elmts :=
4914 Num_Elmts *
4920 -- What we are looking for here is the situation where
4921 -- the RM_Size given would be exactly right if there was
4922 -- a pragma Pack (resulting in the component size being
4923 -- the same as the RM_Size). Furthermore, the component
4924 -- type size must be an odd size (not a multiple of
4925 -- storage unit). If the component RM size is an exact
4926 -- number of storage units that is a power of two, the
4927 -- array is not packed and has a standard representation.
4931 then
4932 -- For implicit packing mode, just set the component
4933 -- size silently.
4941 -- Otherwise give an error message
4943 else
4944 Error_Msg_NE
4946 Error_Msg_N -- CODEFIX
4952 and then Implicit_Packing
4953 and then
4955 or else
4957 or else
4959 then
4960 -- Not a packed array, but indicate the desired
4961 -- component size, for the back-end.
4971 -- If ancestor subtype present, freeze that first. Note that this
4972 -- will also get the base type frozen. Need RM reference ???
4979 -- No ancestor subtype present
4981 else
4982 -- See if we have a nearest ancestor that has a predicate.
4983 -- That catches the case of derived type with a predicate.
4984 -- Need RM reference here ???
4992 -- Freeze base type before freezing the entity (RM 13.14(15))
4999 -- A subtype inherits all the type-related representation aspects
5000 -- from its parents (RM 13.1(8)).
5004 -- For a derived type, freeze its parent type first (RM 13.14(15))
5010 -- A derived type inherits each type-related representation aspect
5011 -- of its parent type that was directly specified before the
5012 -- declaration of the derived type (RM 13.1(15)).
5017 -- Check for incompatible size and alignment for record type
5019 if Warn_On_Size_Alignment
5023 -- If explicit Object_Size clause given assume that the programmer
5024 -- knows what he is doing, and expects the compiler behavior.
5028 -- Check for size not a multiple of alignment
5031 then
5032 declare
5038 begin
5041 -- Give a warning
5045 Error_Msg_NE
5051 else
5053 Error_Msg_NE
5066 -- Array type
5071 -- For a class-wide type, the corresponding specific type is
5072 -- frozen as well (RM 13.14(15))
5077 -- If the base type of the class-wide type is still incomplete,
5078 -- the class-wide remains unfrozen as well. This is legal when
5079 -- E is the formal of a primitive operation of some other type
5080 -- which is being frozen.
5087 -- The equivalent type associated with a class-wide subtype needs
5088 -- to be frozen to ensure that its layout is done.
5092 then
5096 -- Generate an itype reference for a library-level class-wide type
5097 -- at the freeze point. Otherwise the first explicit reference to
5098 -- the type may appear in an inner scope which will be rejected by
5099 -- the back-end.
5103 then
5104 declare
5107 begin
5110 -- From a gigi point of view, a class-wide subtype derives
5111 -- from its record equivalent type. As a result, the itype
5112 -- reference must appear after the freeze node of the
5113 -- equivalent type or gigi will reject the reference.
5117 then
5119 else
5125 -- For a record type or record subtype, freeze all component types
5126 -- (RM 13.14(15)). We test for E_Record_(sub)Type here, rather than
5127 -- using Is_Record_Type, because we don't want to attempt the freeze
5128 -- for the case of a private type with record extension (we will do
5129 -- that later when the full type is frozen).
5134 then
5137 -- For a concurrent type, freeze corresponding record type. This does
5138 -- not correspond to any specific rule in the RM, but the record type
5139 -- is essentially part of the concurrent type. Also freeze all local
5140 -- entities. This includes record types created for entry parameter
5141 -- blocks and whatever local entities may appear in the private part.
5155 -- The guard on the presence of the Etype seems to be needed
5156 -- for some CodePeer (-gnatcC) cases, but not clear why???
5161 then
5172 -- Private types are required to point to the same freeze node as
5173 -- their corresponding full views. The freeze node itself has to
5174 -- point to the partial view of the entity (because from the partial
5175 -- view, we can retrieve the full view, but not the reverse).
5176 -- However, in order to freeze correctly, we need to freeze the full
5177 -- view. If we are freezing at the end of a scope (or within the
5178 -- scope) of the private type, the partial and full views will have
5179 -- been swapped, the full view appears first in the entity chain and
5180 -- the swapping mechanism ensures that the pointers are properly set
5181 -- (on scope exit).
5183 -- If we encounter the partial view before the full view (e.g. when
5184 -- freezing from another scope), we freeze the full view, and then
5185 -- set the pointers appropriately since we cannot rely on swapping to
5186 -- fix things up (subtypes in an outer scope might not get swapped).
5188 -- If the full view is itself private, the above requirements apply
5189 -- to the underlying full view instead of the full view. But there is
5190 -- no swapping mechanism for the underlying full view so we need to
5191 -- set the pointers appropriately in both cases.
5195 then
5196 -- The construction of the dispatch table associated with library
5197 -- level tagged types forces freezing of all the primitives of the
5198 -- type, which may cause premature freezing of the partial view.
5199 -- For example:
5201 -- package Pkg is
5202 -- type T is tagged private;
5203 -- type DT is new T with private;
5204 -- procedure Prim (X : in out T; Y : in out DT'Class);
5205 -- private
5206 -- type T is tagged null record;
5207 -- Obj : T;
5208 -- type DT is new T with null record;
5209 -- end;
5211 -- In this case the type will be frozen later by the usual
5212 -- mechanism: an object declaration, an instantiation, or the
5213 -- end of a declarative part.
5217 then
5221 -- Case of full view present
5225 -- If full view has already been frozen, then no further
5226 -- processing is required
5232 -- Otherwise freeze full view and patch the pointers so that
5233 -- the freeze node will elaborate both views in the back end.
5234 -- However, if full view is itself private, freeze underlying
5235 -- full view instead and patch the pointers so that the freeze
5236 -- node will elaborate the three views in the back end.
5238 else
5239 declare
5242 begin
5245 then
5253 then
5260 else
5273 else
5274 -- {Incomplete,Private}_Subtypes with Full_Views
5275 -- constrained by discriminants.
5286 -- AI-117 requires that the convention of a partial view be the
5287 -- same as the convention of the full view. Note that this is a
5288 -- recognized breach of privacy, but it's essential for logical
5289 -- consistency of representation, and the lack of a rule in
5290 -- RM95 was an oversight.
5297 -- Size information is copied from the full view to the
5298 -- incomplete or private view for consistency.
5300 -- We skip this is the full view is not a type. This is very
5301 -- strange of course, and can only happen as a result of
5302 -- certain illegalities, such as a premature attempt to derive
5303 -- from an incomplete type.
5312 -- Case of underlying full view present
5316 then
5321 -- Patch the pointers so that the freeze node will elaborate
5322 -- both views in the back end.
5331 else
5341 -- Case of no full view present. If entity is derived or subtype,
5342 -- it is safe to freeze, correctness depends on the frozen status
5343 -- of parent. Otherwise it is either premature usage, or a Taft
5344 -- amendment type, so diagnosis is at the point of use and the
5345 -- type might be frozen later.
5350 else
5355 -- For access subprogram, freeze types of all formals, the return
5356 -- type was already frozen, since it is the Etype of the function.
5357 -- Formal types can be tagged Taft amendment types, but otherwise
5358 -- they cannot be incomplete.
5366 then
5370 -- AI05-151: Incomplete types are allowed in access to
5371 -- subprogram specifications.
5374 Error_Msg_NE
5385 -- For access to a protected subprogram, freeze the equivalent type
5386 -- (however this is not set if we are not generating code or if this
5387 -- is an anonymous type used just for resolution).
5395 -- Generic types are never seen by the back-end, and are also not
5396 -- processed by the expander (since the expander is turned off for
5397 -- generic processing), so we never need freeze nodes for them.
5403 -- Some special processing for non-generic types to complete
5404 -- representation details not known till the freeze point.
5409 -- Some error checks required for ordinary fixed-point type. Defer
5410 -- these till the freeze-point since we need the small and range
5411 -- values. We only do these checks for base types
5416 Error_Msg_N
5421 Error_Msg_N
5427 Error_Msg_N
5433 Error_Msg_N
5445 and then Warn_On_Suspicious_Modulus_Value
5446 then
5450 -- The pool applies to named and anonymous access types, but not
5451 -- to subprogram and to internal types generated for 'Access
5452 -- references.
5457 then
5458 -- If a pragma Default_Storage_Pool applies, and this type has no
5459 -- Storage_Pool or Storage_Size clause (which must have occurred
5460 -- before the freezing point), then use the default. This applies
5461 -- only to base types.
5463 -- None of this applies to access to subprograms, for which there
5464 -- are clearly no pools.
5470 then
5471 -- Case of pragma Default_Storage_Pool (null)
5476 -- Case of pragma Default_Storage_Pool (storage_pool_NAME)
5478 else
5483 -- Check restriction for standard storage pool
5489 -- Deal with error message for pure access type. This is not an
5490 -- error in Ada 2005 if there is no pool (see AI-366).
5496 then
5500 Error_Msg_N
5504 Error_Msg_N
5507 else
5508 Error_Msg_N
5515 -- Case of composite types
5519 -- AI-117 requires that all new primitives of a tagged type must
5520 -- inherit the convention of the full view of the type. Inherited
5521 -- and overriding operations are defined to inherit the convention
5522 -- of their parent or overridden subprogram (also specified in
5523 -- AI-117), which will have occurred earlier (in Derive_Subprogram
5524 -- and New_Overloaded_Entity). Here we set the convention of
5525 -- primitives that are still convention Ada, which will ensure
5526 -- that any new primitives inherit the type's convention. Class-
5527 -- wide types can have a foreign convention inherited from their
5528 -- specific type, but are excluded from this since they don't have
5529 -- any associated primitives.
5534 then
5535 declare
5539 begin
5551 -- If the type is a simple storage pool type, then this is where
5552 -- we attempt to locate and validate its Allocate, Deallocate, and
5553 -- Storage_Size operations (the first is required, and the latter
5554 -- two are optional). We also verify that the full type for a
5555 -- private type is allowed to be a simple storage pool type.
5559 then
5560 -- If the type is marked Has_Private_Declaration, then this is
5561 -- a full type for a private type that was specified with the
5562 -- pragma Simple_Storage_Pool_Type, and here we ensure that the
5563 -- pragma is allowed for the full type (for example, it can't
5564 -- be an array type, or a nonlimited record type).
5569 then
5571 Error_Msg_N
5582 procedure Validate_Simple_Pool_Op_Formal
5589 -- Validate one formal Pool_Op_Formal of the candidate pool
5590 -- operation Pool_Op. The formal must be of Expected_Type
5591 -- and have mode Expected_Mode. OK_Formal will be set to
5592 -- False if the formal doesn't match. If OK_Formal is False
5593 -- on entry, then the formal will effectively be ignored
5594 -- (because validation of the pool op has already failed).
5595 -- Upon return, Pool_Op_Formal will be updated to the next
5596 -- formal, if any.
5598 procedure Validate_Simple_Pool_Operation
5600 -- Search for and validate a simple pool operation with the
5601 -- name Op_Name. If the name is Allocate, then there must be
5602 -- exactly one such primitive operation for the simple pool
5603 -- type. If the name is Deallocate or Storage_Size, then
5604 -- there can be at most one such primitive operation. The
5605 -- profile of the located primitive must conform to what
5606 -- is expected for each operation.
5608 ------------------------------------
5609 -- Validate_Simple_Pool_Op_Formal --
5610 ------------------------------------
5612 procedure Validate_Simple_Pool_Op_Formal
5619 is
5620 begin
5621 -- If OK_Formal is False on entry, then simply ignore
5622 -- the formal, because an earlier formal has already
5623 -- been flagged.
5628 -- If no formal is passed in, then issue an error for a
5629 -- missing formal.
5632 Error_Msg_NE
5642 -- If the pool type was expected for this formal, then
5643 -- this will not be considered a candidate operation
5644 -- for the simple pool, so we unset OK_Formal so that
5645 -- the op and any later formals will be ignored.
5652 else
5653 Error_Msg_NE
5660 -- Issue error if formal's mode is not the expected one
5663 Error_Msg_N
5665 Pool_Op_Formal);
5668 -- Advance to the next formal
5673 ------------------------------------
5674 -- Validate_Simple_Pool_Operation --
5675 ------------------------------------
5677 procedure Validate_Simple_Pool_Operation
5679 is
5685 begin
5686 pragma Assert
5688 Name_Deallocate,
5689 Name_Storage_Size));
5693 -- For each homonym declared immediately in the scope
5694 -- of the simple storage pool type, determine whether
5695 -- the homonym is an operation of the pool type, and,
5696 -- if so, check that its profile is as expected for
5697 -- a simple pool operation of that name.
5703 then
5708 -- The first parameter must be of the pool type
5709 -- in order for the operation to qualify.
5712 Validate_Simple_Pool_Op_Formal
5715 else
5716 Validate_Simple_Pool_Op_Formal
5721 -- If another operation with this name has already
5722 -- been located for the type, then flag an error,
5723 -- since we only allow the type to have a single
5724 -- such primitive.
5727 Error_Msg_NE
5732 -- In the case of Allocate and Deallocate, a formal
5733 -- of type System.Address is required.
5736 Validate_Simple_Pool_Op_Formal
5741 Validate_Simple_Pool_Op_Formal
5746 -- In the case of Allocate and Deallocate, formals
5747 -- of type Storage_Count are required as the third
5748 -- and fourth parameters.
5751 Validate_Simple_Pool_Op_Formal
5754 Validate_Simple_Pool_Op_Formal
5759 -- If no mismatched formals have been found (Is_OK)
5760 -- and no excess formals are present, then this
5761 -- operation has been validated, so record it.
5771 -- There must be a valid Allocate operation for the type,
5772 -- so issue an error if none was found.
5776 then
5782 -- Simple pool operations can't be abstract
5785 Error_Msg_N
5790 -- The Storage_Size operation must be a function with
5791 -- Storage_Count as its result type.
5795 Error_Msg_N
5799 Error_Msg_NE
5804 -- Allocate and Deallocate must be procedures
5807 Error_Msg_N
5813 -- Start of processing for Validate_Simple_Pool_Ops
5815 begin
5823 -- Now that all types from which E may depend are frozen, see if the
5824 -- size is known at compile time, if it must be unsigned, or if
5825 -- strict alignment is required
5834 -- Do not allow a size clause for a type which does not have a size
5835 -- that is known at compile time
5839 then
5840 -- Suppress this message if errors posted on E, even if we are
5841 -- in all errors mode, since this is often a junk message
5844 Error_Msg_N
5850 -- Now we set/verify the representation information, in particular
5851 -- the size and alignment values. This processing is not required for
5852 -- generic types, since generic types do not play any part in code
5853 -- generation, and so the size and alignment values for such types
5854 -- are irrelevant. Ditto for types declared within a generic unit,
5855 -- which may have components that depend on generic parameters, and
5856 -- that will be recreated in an instance.
5861 -- Otherwise we call the layout procedure
5863 else
5867 -- If this is an access to subprogram whose designated type is itself
5868 -- a subprogram type, the return type of this anonymous subprogram
5869 -- type must be decorated as well.
5873 then
5877 -- If the type has a Defaut_Value/Default_Component_Value aspect,
5878 -- this is where we analye the expression (after the type is frozen,
5879 -- since in the case of Default_Value, we are analyzing with the
5880 -- type itself, and we treat Default_Component_Value similarly for
5881 -- the sake of uniformity).
5884 declare
5889 begin
5894 else
5905 Flag_Non_Static_Expr
5912 -- End of freeze processing for type entities
5915 -- Here is where we logically freeze the current entity. If it has a
5916 -- freeze node, then this is the point at which the freeze node is
5917 -- linked into the result list.
5921 -- If a freeze node is already allocated, use it, otherwise allocate
5922 -- a new one. The preallocation happens in the case of anonymous base
5923 -- types, where we preallocate so that we can set First_Subtype_Link.
5924 -- Note that we reset the Sloc to the current freeze location.
5930 else
5941 -- A final pass over record types with discriminants. If the type
5942 -- has an incomplete declaration, there may be constrained access
5943 -- subtypes declared elsewhere, which do not depend on the discrimi-
5944 -- nants of the type, and which are used as component types (i.e.
5945 -- the full view is a recursive type). The designated types of these
5946 -- subtypes can only be elaborated after the type itself, and they
5947 -- need an itype reference.
5951 then
5952 declare
5957 begin
5967 then
5979 -- When a type is frozen, the first subtype of the type is frozen as
5980 -- well (RM 13.14(15)). This has to be done after freezing the type,
5981 -- since obviously the first subtype depends on its own base type.
5986 -- If we just froze a tagged non-class wide record, then freeze the
5987 -- corresponding class-wide type. This must be done after the tagged
5988 -- type itself is frozen, because the class-wide type refers to the
5989 -- tagged type which generates the class.
5994 then
6001 -- Special handling for subprograms
6005 -- If subprogram has address clause then reset Is_Public flag, since
6006 -- we do not want the backend to generate external references.
6010 then
6018 -----------------------------
6019 -- Freeze_Enumeration_Type --
6020 -----------------------------
6023 begin
6024 -- By default, if no size clause is present, an enumeration type with
6025 -- Convention C is assumed to interface to a C enum, and has integer
6026 -- size. This applies to types. For subtypes, verify that its base
6027 -- type has no size clause either. Treat other foreign conventions
6028 -- in the same way, and also make sure alignment is set right.
6035 -- Don't do this if Short_Enums on target
6037 and then not Target_Short_Enums
6038 then
6042 -- Normal Ada case or size clause present or not Long_C_Enums on target
6044 else
6045 -- If the enumeration type interfaces to C, and it has a size clause
6046 -- that specifies less than int size, it warrants a warning. The
6047 -- user may intend the C type to be an enum or a char, so this is
6048 -- not by itself an error that the Ada compiler can detect, but it
6049 -- it is a worth a heads-up. For Boolean and Character types we
6050 -- assume that the programmer has the proper C type in mind.
6058 -- Don't do this if Short_Enums on target
6060 and then not Target_Short_Enums
6061 then
6062 Error_Msg_N
6070 -----------------------
6071 -- Freeze_Expression --
6072 -----------------------
6083 -- This flag is set true if the entity must be frozen outside the
6084 -- current subprogram. This happens in the case of expander generated
6085 -- subprograms (_Init_Proc, _Input, _Output, _Read, _Write) which do
6086 -- not freeze all entities like other bodies, but which nevertheless
6087 -- may reference entities that have to be frozen before the body and
6088 -- obviously cannot be frozen inside the body.
6091 -- If the expression is an array aggregate, the type of the component
6092 -- expressions is also frozen. If the component type is an access type
6093 -- and the expressions include allocators, the designed type is frozen
6094 -- as well.
6097 -- Given an N_Handled_Sequence_Of_Statements node N, determines whether
6098 -- it is the handled statement sequence of an expander-generated
6099 -- subprogram (init proc, stream subprogram, or renaming as body).
6100 -- If so, this is not a freezing context.
6102 -----------------------------------------
6103 -- Find_Aggregate_Component_Desig_Type --
6104 -----------------------------------------
6110 begin
6136 ----------------------
6137 -- In_Expanded_Body --
6138 ----------------------
6144 begin
6147 else
6154 else
6157 -- The following are expander-created bodies, or bodies that
6158 -- are not freeze points.
6167 N_Subprogram_Renaming_Declaration,
6168 N_Expression_Function))
6169 then
6171 else
6177 -- Start of processing for Freeze_Expression
6179 begin
6180 -- Immediate return if freezing is inhibited. This flag is set by the
6181 -- analyzer to stop freezing on generated expressions that would cause
6182 -- freezing if they were in the source program, but which are not
6183 -- supposed to freeze, since they are created.
6189 -- If expression is non-static, then it does not freeze in a default
6190 -- expression, see section "Handling of Default Expressions" in the
6191 -- spec of package Sem for further details. Note that we have to make
6192 -- sure that we actually have a real expression (if we have a subtype
6193 -- indication, we can't test Is_OK_Static_Expression). However, we
6194 -- exclude the case of the prefix of an attribute of a static scalar
6195 -- subtype from this early return, because static subtype attributes
6196 -- should always cause freezing, even in default expressions, but
6197 -- the attribute may not have been marked as static yet (because in
6198 -- Resolve_Attribute, the call to Eval_Attribute follows the call of
6199 -- Freeze_Expression on the prefix).
6201 if In_Spec_Exp
6208 then
6212 -- Freeze type of expression if not frozen already
6220 -- Base type may be an derived numeric type that is frozen at
6221 -- the point of declaration, but first_subtype is still unfrozen.
6228 -- For entity name, freeze entity if not frozen already. A special
6229 -- exception occurs for an identifier that did not come from source.
6230 -- We don't let such identifiers freeze a non-internal entity, i.e.
6231 -- an entity that did come from source, since such an identifier was
6232 -- generated by the expander, and cannot have any semantic effect on
6233 -- the freezing semantics. For example, this stops the parameter of
6234 -- an initialization procedure from freezing the variable.
6241 then
6248 else
6252 -- For an allocator freeze designated type if not frozen already
6254 -- For an aggregate whose component type is an access type, freeze the
6255 -- designated type now, so that its freeze does not appear within the
6256 -- loop that might be created in the expansion of the aggregate. If the
6257 -- designated type is a private type without full view, the expression
6258 -- cannot contain an allocator, so the type is not frozen.
6260 -- For a function, we freeze the entity when the subprogram declaration
6261 -- is frozen, but a function call may appear in an initialization proc.
6262 -- before the declaration is frozen. We need to generate the extra
6263 -- formals, if any, to ensure that the expansion of the call includes
6264 -- the proper actuals. This only applies to Ada subprograms, not to
6265 -- imported ones.
6276 then
6278 -- Check whether aggregate includes allocators.
6283 when N_Selected_Component |
6284 N_Indexed_Component |
6285 N_Slice =>
6296 then
6307 then
6311 -- All done if nothing needs freezing
6316 then
6320 -- Examine the enclosing context by climbing the parent chain. The
6321 -- traversal serves two purposes - to detect scenarios where freezeing
6322 -- is not needed and to find the proper insertion point for the freeze
6323 -- nodes. Although somewhat similar to Insert_Actions, this traversal
6324 -- is freezing semantics-sensitive. Inserting freeze nodes blindly in
6325 -- the tree may result in types being frozen too early.
6328 loop
6331 -- If we don't have a parent, then we are not in a well-formed tree.
6332 -- This is an unusual case, but there are some legitimate situations
6333 -- in which this occurs, notably when the expressions in the range of
6334 -- a type declaration are resolved. We simply ignore the freeze
6335 -- request in this case. Is this right ???
6341 -- See if we have got to an appropriate point in the tree
6345 -- A special test for the exception of (RM 13.14(8)) for the case
6346 -- of per-object expressions (RM 3.8(18)) occurring in component
6347 -- definition or a discrete subtype definition. Note that we test
6348 -- for a component declaration which includes both cases we are
6349 -- interested in, and furthermore the tree does not have explicit
6350 -- nodes for either of these two constructs.
6354 -- The case we want to test for here is an identifier that is
6355 -- a per-object expression, this is either a discriminant that
6356 -- appears in a context other than the component declaration
6357 -- or it is a reference to the type of the enclosing construct.
6359 -- For either of these cases, we skip the freezing
6361 if not In_Spec_Expression
6364 then
6365 -- We recognize the discriminant case by just looking for
6366 -- a reference to a discriminant. It can only be one for
6367 -- the enclosing construct. Skip freezing in this case.
6372 -- For the case of a reference to the enclosing record,
6373 -- (or task or protected type), we look for a type that
6374 -- matches the current scope.
6381 -- If we have an enumeration literal that appears as the choice in
6382 -- the aggregate of an enumeration representation clause, then
6383 -- freezing does not occur (RM 13.14(10)).
6387 -- The case we are looking for is an enumeration literal
6391 then
6392 -- If enumeration literal appears directly as the choice,
6393 -- do not freeze (this is the normal non-overloaded case)
6397 then
6400 -- If enumeration literal appears as the name of function
6401 -- which is the choice, then also do not freeze. This
6402 -- happens in the overloaded literal case, where the
6403 -- enumeration literal is temporarily changed to a function
6404 -- call for overloading analysis purposes.
6407 and then
6409 and then
6411 then
6416 -- Normally if the parent is a handled sequence of statements,
6417 -- then the current node must be a statement, and that is an
6418 -- appropriate place to insert a freeze node.
6422 -- An exception occurs when the sequence of statements is for
6423 -- an expander generated body that did not do the usual freeze
6424 -- all operation. In this case we usually want to freeze
6425 -- outside this body, not inside it, and we skip past the
6426 -- subprogram body that we are inside.
6429 declare
6433 begin
6434 -- Freeze the entity only when it is declared inside the
6435 -- body of the expander generated procedure. This case
6436 -- is recognized by the scope of the entity or its type,
6437 -- which is either the spec for some enclosing body, or
6438 -- (in the case of init_procs, for which there are no
6439 -- separate specs) the current scope.
6445 or else
6447 then
6453 then
6458 -- An expression function may act as a completion of
6459 -- a function declaration. As such, it can reference
6460 -- entities declared between the two views:
6462 -- Hidden []; -- 1
6463 -- function F return ...;
6464 -- private
6465 -- function Hidden return ...;
6466 -- function F return ... is (Hidden); -- 2
6468 -- Refering to the example above, freezing the expression
6469 -- of F (2) would place Hidden's freeze node (1) in the
6470 -- wrong place. Avoid explicit freezing and let the usual
6471 -- scenarios do the job - for example, reaching the end
6472 -- of the private declarations, or a call to F.
6475 N_Expression_Function
6476 then
6479 -- Freeze outside the body
6481 else
6487 -- Here if normal case where we are in handled statement
6488 -- sequence and want to do the insertion right there.
6490 else
6494 -- If parent is a body or a spec or a block, then the current node
6495 -- is a statement or declaration and we can insert the freeze node
6496 -- before it.
6498 when N_Block_Statement |
6499 N_Entry_Body |
6500 N_Package_Body |
6501 N_Package_Specification |
6502 N_Protected_Body |
6503 N_Subprogram_Body |
6506 -- The expander is allowed to define types in any statements list,
6507 -- so any of the following parent nodes also mark a freezing point
6508 -- if the actual node is in a list of statements or declarations.
6510 when N_Abortable_Part |
6511 N_Accept_Alternative |
6512 N_And_Then |
6513 N_Case_Statement_Alternative |
6514 N_Compilation_Unit_Aux |
6515 N_Conditional_Entry_Call |
6516 N_Delay_Alternative |
6517 N_Elsif_Part |
6518 N_Entry_Call_Alternative |
6519 N_Exception_Handler |
6520 N_Extended_Return_Statement |
6521 N_Freeze_Entity |
6522 N_If_Statement |
6523 N_Or_Else |
6524 N_Selective_Accept |
6525 N_Triggering_Alternative =>
6529 -- Freeze nodes produced by an expression coming from the Actions
6530 -- list of a N_Expression_With_Actions node must remain within the
6531 -- Actions list. Inserting the freeze nodes further up the tree
6532 -- may lead to use before declaration issues in the case of array
6533 -- types.
6538 then
6542 -- Note: N_Loop_Statement is a special case. A type that appears
6543 -- in the source can never be frozen in a loop (this occurs only
6544 -- because of a loop expanded by the expander), so we keep on
6545 -- going. Otherwise we terminate the search. Same is true of any
6546 -- entity which comes from source. (if they have predefined type,
6547 -- that type does not appear to come from source, but the entity
6548 -- should not be frozen here).
6554 -- For all other cases, keep looking at parents
6560 -- We fall through the case if we did not yet find the proper
6561 -- place in the free for inserting the freeze node, so climb.
6566 -- If the expression appears in a record or an initialization procedure,
6567 -- the freeze nodes are collected and attached to the current scope, to
6568 -- be inserted and analyzed on exit from the scope, to insure that
6569 -- generated entities appear in the correct scope. If the expression is
6570 -- a default for a discriminant specification, the scope is still void.
6571 -- The expression can also appear in the discriminant part of a private
6572 -- or concurrent type.
6574 -- If the expression appears in a constrained subcomponent of an
6575 -- enclosing record declaration, the freeze nodes must be attached to
6576 -- the outer record type so they can eventually be placed in the
6577 -- enclosing declaration list.
6579 -- The other case requiring this special handling is if we are in a
6580 -- default expression, since in that case we are about to freeze a
6581 -- static type, and the freeze scope needs to be the outer scope, not
6582 -- the scope of the subprogram with the default parameter.
6584 -- For default expressions and other spec expressions in generic units,
6585 -- the Move_Freeze_Nodes mechanism (see sem_ch12.adb) takes care of
6586 -- placing them at the proper place, after the generic unit.
6589 or else Freeze_Outside
6594 then
6595 declare
6600 begin
6613 -- The current scope may be that of a constrained component of
6614 -- an enclosing record declaration, or of a loop of an enclosing
6615 -- quantified expression, which is above the current scope in the
6616 -- scope stack. Indeed in the context of a quantified expression,
6617 -- a scope is created and pushed above the current scope in order
6618 -- to emulate the loop-like behavior of the quantified expression.
6619 -- If the expression is within a top-level pragma, as for a pre-
6620 -- condition on a library-level subprogram, nothing to do.
6625 N_Quantified_Expression)
6626 then
6633 Freeze_Nodes;
6634 else
6644 -- Now we have the right place to do the freezing. First, a special
6645 -- adjustment, if we are in spec-expression analysis mode, these freeze
6646 -- actions must not be thrown away (normally all inserted actions are
6647 -- thrown away in this mode. However, the freeze actions are from static
6648 -- expressions and one of the important reasons we are doing this
6649 -- special analysis is to get these freeze actions. Therefore we turn
6650 -- off the In_Spec_Expression mode to propagate these freeze actions.
6651 -- This also means they get properly analyzed and expanded.
6655 -- Freeze the designated type of an allocator (RM 13.14(13))
6661 -- Freeze type of expression (RM 13.14(10)). Note that we took care of
6662 -- the enumeration representation clause exception in the loop above.
6668 -- Freeze name if one is present (RM 13.14(11))
6674 -- Restore In_Spec_Expression flag
6679 -----------------------------
6680 -- Freeze_Fixed_Point_Type --
6681 -----------------------------
6683 -- Certain fixed-point types and subtypes, including implicit base types
6684 -- and declared first subtypes, have not yet set up a range. This is
6685 -- because the range cannot be set until the Small and Size values are
6686 -- known, and these are not known till the type is frozen.
6688 -- To signal this case, Scalar_Range contains an unanalyzed syntactic range
6689 -- whose bounds are unanalyzed real literals. This routine will recognize
6690 -- this case, and transform this range node into a properly typed range
6691 -- with properly analyzed and resolved values.
6709 -- Returns size of type with given bounds. Also leaves these
6710 -- bounds set as the current bounds of the Typ.
6712 -----------
6713 -- Fsize --
6714 -----------
6717 begin
6723 -- Start of processing for Freeze_Fixed_Point_Type
6725 begin
6726 -- If Esize of a subtype has not previously been set, set it now
6733 else
6738 -- Immediate return if the range is already analyzed. This means that
6739 -- the range is already set, and does not need to be computed by this
6740 -- routine.
6746 -- Immediate return if either of the bounds raises Constraint_Error
6750 then
6757 -- Ordinary fixed-point case
6761 -- For the ordinary fixed-point case, we are allowed to fudge the
6762 -- end-points up or down by small. Generally we prefer to fudge up,
6763 -- i.e. widen the bounds for non-model numbers so that the end points
6764 -- are included. However there are cases in which this cannot be
6765 -- done, and indeed cases in which we may need to narrow the bounds.
6766 -- The following circuit makes the decision.
6768 -- Note: our terminology here is that Incl_EP means that the bounds
6769 -- are widened by Small if necessary to include the end points, and
6770 -- Excl_EP means that the bounds are narrowed by Small to exclude the
6771 -- end-points if this reduces the size.
6773 -- Note that in the Incl case, all we care about is including the
6774 -- end-points. In the Excl case, we want to narrow the bounds as
6775 -- much as permitted by the RM, to give the smallest possible size.
6792 begin
6793 -- First step. Base types are required to be symmetrical. Right
6794 -- now, the base type range is a copy of the first subtype range.
6795 -- This will be corrected before we are done, but right away we
6796 -- need to deal with the case where both bounds are non-negative.
6797 -- In this case, we set the low bound to the negative of the high
6798 -- bound, to make sure that the size is computed to include the
6799 -- required sign. Note that we do not need to worry about the
6800 -- case of both bounds negative, because the sign will be dealt
6801 -- with anyway. Furthermore we can't just go making such a bound
6802 -- symmetrical, since in a twos-complement system, there is an
6803 -- extra negative value which could not be accommodated on the
6804 -- positive side.
6809 then
6814 -- Compute the fudged bounds. If the number is a model number,
6815 -- then we do nothing to include it, but we are allowed to backoff
6816 -- to the next adjacent model number when we exclude it. If it is
6817 -- not a model number then we straddle the two values with the
6818 -- model numbers on either side.
6824 else
6828 -- The low value excluding the end point is Small greater, but
6829 -- we do not do this exclusion if the low value is positive,
6830 -- since it can't help the size and could actually hurt by
6831 -- crossing the high bound.
6836 -- If the value went from negative to zero, then we have the
6837 -- case where Loval_Incl_EP is the model number just below
6838 -- zero, so we want to stick to the negative value for the
6839 -- base type to maintain the condition that the size will
6840 -- include signed values.
6844 then
6848 else
6852 -- Similar processing for upper bound and high value
6858 else
6864 else
6868 -- One further adjustment is needed. In the case of subtypes, we
6869 -- cannot go outside the range of the base type, or we get
6870 -- peculiarities, and the base type range is already set. This
6871 -- only applies to the Incl values, since clearly the Excl values
6872 -- are already as restricted as they are allowed to be.
6879 -- Get size including and excluding end points
6884 -- No need to exclude end-points if it does not reduce size
6894 -- Now we set the actual size to be used. We want to use the
6895 -- bounds fudged up to include the end-points but only if this
6896 -- can be done without violating a specifically given size
6897 -- size clause or causing an unacceptable increase in size.
6899 -- Case of size clause given
6903 -- Use the inclusive size only if it is consistent with
6904 -- the explicitly specified size.
6911 -- If the inclusive size is too large, we try excluding
6912 -- the end-points (will be caught later if does not work).
6914 else
6920 -- Case of size clause not given
6922 else
6923 -- If we have a base type whose corresponding first subtype
6924 -- has an explicit size that is large enough to include our
6925 -- end-points, then do so. There is no point in working hard
6926 -- to get a base type whose size is smaller than the specified
6927 -- size of the first subtype.
6933 then
6938 -- If excluding the end-points makes the size smaller and
6939 -- results in a size of 8,16,32,64, then we take the smaller
6940 -- size. For the 64 case, this is compulsory. For the other
6941 -- cases, it seems reasonable. We like to include end points
6942 -- if we can, but not at the expense of moving to the next
6943 -- natural boundary of size.
6947 then
6952 -- Otherwise we can definitely include the end points
6954 else
6960 -- One pathological case: normally we never fudge a low bound
6961 -- down, since it would seem to increase the size (if it has
6962 -- any effect), but for ranges containing single value, or no
6963 -- values, the high bound can be small too large. Consider:
6965 -- type t is delta 2.0**(-14)
6966 -- range 131072.0 .. 0;
6968 -- That lower bound is *just* outside the range of 32 bits, and
6969 -- does need fudging down in this case. Note that the bounds
6970 -- will always have crossed here, since the high bound will be
6971 -- fudged down if necessary, as in the case of:
6973 -- type t is delta 2.0**(-14)
6974 -- range 131072.0 .. 131072.0;
6976 -- So we detect the situation by looking for crossed bounds,
6977 -- and if the bounds are crossed, and the low bound is greater
6978 -- than zero, we will always back it off by small, since this
6979 -- is completely harmless.
6986 -- And of course, we need to do exactly the same parallel
6987 -- fudge for flat ranges in the negative region.
7000 -- For the decimal case, none of this fudging is required, since there
7001 -- are no end-point problems in the decimal case (the end-points are
7002 -- always included).
7004 else
7008 -- At this stage, the actual size has been calculated and the proper
7009 -- required bounds are stored in the low and high bounds.
7013 Error_Msg_N
7015 Typ);
7019 -- Check size against explicit given size
7025 Error_Msg_NE
7029 else
7033 -- Increase size to next natural boundary if no size clause given
7035 else
7042 else
7050 -- If we have a base type, then expand the bounds so that they extend to
7051 -- the full width of the allocated size in bits, to avoid junk range
7052 -- checks on intermediate computations.
7059 -- Final step is to reanalyze the bounds using the proper type
7060 -- and set the Corresponding_Integer_Value fields of the literals.
7066 -- Resolve with universal fixed if the base type, and the base type if
7067 -- it is a subtype. Note we can't resolve the base type with itself,
7068 -- that would be a reference before definition.
7072 else
7076 -- Set corresponding integer value for bound
7078 Set_Corresponding_Integer_Value
7081 -- Similar processing for high bound
7089 else
7093 Set_Corresponding_Integer_Value
7096 -- Set type of range to correspond to bounds
7100 -- Set Esize to calculated size if not set already
7106 -- Set RM_Size if not already set. If already set, check value
7108 declare
7111 begin
7116 Error_Msg_NE
7121 else
7127 ------------------
7128 -- Freeze_Itype --
7129 ------------------
7134 begin
7143 --------------------------
7144 -- Freeze_Static_Object --
7145 --------------------------
7150 -- Exception raised if the type of a static object cannot be made
7151 -- static. This happens if the type depends on non-global objects.
7154 -- Called to ensure that an expression used as part of a type definition
7155 -- is statically allocatable, which means that the expression type is
7156 -- statically allocatable, and the expression is either static, or a
7157 -- reference to a library level constant.
7160 -- Called to mark a type as static, checking that it is possible
7161 -- to set the type as static. If it is not possible, then the
7162 -- exception Cannot_Be_Static is raised.
7164 -----------------------------
7165 -- Ensure_Expression_Is_SA --
7166 -----------------------------
7171 begin
7183 then
7191 -----------------------
7192 -- Ensure_Type_Is_SA --
7193 -----------------------
7199 begin
7200 -- If type is library level, we are all set
7206 -- We are also OK if the type already marked as statically allocated,
7207 -- which means we processed it before.
7213 -- Mark type as statically allocated
7217 -- Check that it is safe to statically allocate this type
7235 declare
7239 begin
7251 else
7260 then
7279 else
7284 -- Start of processing for Freeze_Static_Object
7286 begin
7289 exception
7292 -- If the object that cannot be static is imported or exported, then
7293 -- issue an error message saying that this object cannot be imported
7294 -- or exported. If it has an address clause it is an overlay in the
7295 -- current partition and the static requirement is not relevant.
7296 -- Do not issue any error message when ignoring rep clauses.
7303 Error_Msg_N
7307 -- Otherwise must be exported, something is wrong if compiler
7308 -- is marking something as statically allocated which cannot be).
7311 Error_Msg_N
7316 -----------------------
7317 -- Freeze_Subprogram --
7318 -----------------------
7324 begin
7325 -- Subprogram may not have an address clause unless it is imported
7329 Error_Msg_N
7336 -- Reset the Pure indication on an imported subprogram unless an
7337 -- explicit Pure_Function pragma was present or the subprogram is an
7338 -- intrinsic. We do this because otherwise it is an insidious error
7339 -- to call a non-pure function from pure unit and have calls
7340 -- mysteriously optimized away. What happens here is that the Import
7341 -- can bypass the normal check to ensure that pure units call only pure
7342 -- subprograms.
7344 -- The reason for the intrinsic exception is that in general, intrinsic
7345 -- functions (such as shifts) are pure anyway. The only exceptions are
7346 -- the intrinsics in GNAT.Source_Info, and that unit is not marked Pure
7347 -- in any case, so no problem arises.
7353 then
7357 -- For non-foreign convention subprograms, this is where we create
7358 -- the extra formals (for accessibility level and constrained bit
7359 -- information). We delay this till the freeze point precisely so
7360 -- that we know the convention.
7366 -- If this is convention Ada and a Valued_Procedure, that's odd
7371 and then Warn_On_Export_Import
7372 then
7373 Error_Msg_N
7378 -- Case of foreign convention
7380 else
7383 -- For foreign conventions, warn about return of unconstrained array
7388 -- If no return type, probably some other error, e.g. a
7389 -- missing full declaration, so ignore.
7394 -- If the return type is generic, we have emitted a warning
7395 -- earlier on, and there is nothing else to check here. Specific
7396 -- instantiations may lead to erroneous behavior.
7401 -- Display warning if returning unconstrained array
7406 -- Check appropriate warning is enabled (should we check for
7407 -- Warnings (Off) on specific entities here, probably so???)
7409 and then Warn_On_Export_Import
7411 -- Exclude the VM case, since return of unconstrained arrays
7412 -- is properly handled in both the JVM and .NET cases.
7415 then
7416 Error_Msg_N
7423 -- If any of the formals for an exported foreign convention
7424 -- subprogram have defaults, then emit an appropriate warning since
7425 -- this is odd (default cannot be used from non-Ada code)
7430 if Warn_On_Export_Import
7432 then
7433 Error_Msg_N
7443 -- Pragma Inline_Always is disallowed for dispatching subprograms
7444 -- because the address of such subprograms is saved in the dispatch
7445 -- table to support dispatching calls, and dispatching calls cannot
7446 -- be inlined. This is consistent with the restriction against using
7447 -- 'Access or 'Address on an Inline_Always subprogram.
7451 then
7452 Error_Msg_N
7456 -- Because of the implicit representation of inherited predefined
7457 -- operators in the front-end, the overriding status of the operation
7458 -- may be affected when a full view of a type is analyzed, and this is
7459 -- not captured by the analysis of the corresponding type declaration.
7460 -- Therefore the correctness of a not-overriding indicator must be
7461 -- rechecked when the subprogram is frozen.
7465 then
7470 ----------------------
7471 -- Is_Fully_Defined --
7472 ----------------------
7475 begin
7484 then
7485 -- Verify that the record type has no components with private types
7486 -- without completion.
7488 declare
7491 begin
7503 -- For the designated type of an access to subprogram, all types in
7504 -- the profile must be fully defined.
7507 declare
7510 begin
7523 else
7529 ---------------------------------
7530 -- Process_Default_Expressions --
7531 ---------------------------------
7533 procedure Process_Default_Expressions
7536 is
7543 begin
7546 -- A subprogram instance and its associated anonymous subprogram share
7547 -- their signature. The default expression functions are defined in the
7548 -- wrapper packages for the anonymous subprogram, and should not be
7549 -- generated again for the instance.
7554 then
7562 -- We work with a copy of the default expression because we
7563 -- do not want to disturb the original, since this would mess
7564 -- up the conformance checking.
7568 -- The analysis of the expression may generate insert actions,
7569 -- which of course must not be executed. We wrap those actions
7570 -- in a procedure that is not called, and later on eliminated.
7571 -- The following cases have no side-effects, and are analyzed
7572 -- directly.
7576 N_Integer_Literal,
7577 N_Character_Literal,
7578 N_String_Literal,
7579 N_Real_Literal)
7583 then
7584 -- If there is no default function, we must still do a full
7585 -- analyze call on the default value, to ensure that all error
7586 -- checks are performed, e.g. those associated with static
7587 -- evaluation. Note: this branch will always be taken if the
7588 -- analyzer is turned off (but we still need the error checks).
7590 -- Note: the setting of parent here is to meet the requirement
7591 -- that we can only analyze the expression while attached to
7592 -- the tree. Really the requirement is that the parent chain
7593 -- be set, we don't actually need to be in the tree.
7598 -- Default expressions are resolved with their own type if the
7599 -- context is generic, to avoid anomalies with private types.
7603 else
7607 -- If that resolved expression will raise constraint error,
7608 -- then flag the default value as raising constraint error.
7609 -- This allows a proper error message on the calls.
7615 -- If the default is a parameterless call, we use the name of
7616 -- the called function directly, and there is no body to build.
7620 then
7623 -- Else construct and analyze the body of a wrapper procedure
7624 -- that contains an object declaration to hold the expression.
7625 -- Given that this is done only to complete the analysis, it
7626 -- simpler to build a procedure than a function which might
7627 -- involve secondary stack expansion.
7629 else
7632 Dbody :=
7634 Specification =>
7641 Object_Definition =>
7645 Handled_Statement_Sequence =>
7662 ----------------------------------------
7663 -- Set_Component_Alignment_If_Not_Set --
7664 ----------------------------------------
7667 begin
7668 -- Ignore if not base type, subtypes don't need anything
7674 -- Do not override existing representation
7685 else
7686 Set_Component_Alignment
7692 --------------------------
7693 -- Set_SSO_From_Default --
7694 --------------------------
7697 begin
7700 then
7702 or else
7705 -- For a record type, if native bit order is specified explicitly,
7706 -- then never set reverse SSO from default.
7708 and then not
7712 then
7713 -- If flags cause reverse storage order, then set the result. Note
7714 -- that we would have ignored the pragma setting the non default
7715 -- storage order in any case, hence the assertion at this point.
7720 -- For a record type, also set reversed bit order. Note that if
7721 -- a bit order has been specified explicitly, then this is a
7722 -- no-op, as per the guard above.
7731 ------------------
7732 -- Undelay_Type --
7733 ------------------
7736 begin
7740 -- Since we don't want T to have a Freeze_Node, we don't want its
7741 -- Full_View or Corresponding_Record_Type to have one either.
7743 -- ??? Fundamentally, this whole handling is unpleasant. What we really
7744 -- want is to be sure that for an Itype that's part of record R and is a
7745 -- subtype of type T, that it's frozen after the later of the freeze
7746 -- points of R and T. We have no way of doing that directly, so what we
7747 -- do is force most such Itypes to be frozen as part of freezing R via
7748 -- this procedure and only delay the ones that need to be delayed
7749 -- (mostly the designated types of access types that are defined as part
7750 -- of the record).
7756 then
7764 then
7769 ------------------
7770 -- Warn_Overlay --
7771 ------------------
7773 procedure Warn_Overlay
7777 is
7779 -- The object to which the address clause applies
7785 begin
7786 -- No warning if address clause overlay warnings are off
7792 -- No warning if there is an explicit initialization
7800 -- We only give the warning for non-imported entities of a type for
7801 -- which a non-null base init proc is defined, or for objects of access
7802 -- types with implicit null initialization, or when Normalize_Scalars
7803 -- applies and the type is scalar or a string type (the latter being
7804 -- tested for because predefined String types are initialized by inline
7805 -- code rather than by an init_proc). Note that we do not give the
7806 -- warning for Initialize_Scalars, since we suppressed initialization
7807 -- in this case. Also, do not warn if Suppress_Initialization is set.
7817 then
7820 then
7825 then
7832 then
7839 -- A function call (most likely to To_Address) is probably not an
7840 -- overlay, so skip warning. Ditto if the function call was inlined
7841 -- and transformed into an entity.
7849 -- If a pragma Import follows, we assume that it is for the current
7850 -- target of the address clause, and skip the warning.
7855 then
7861 Error_Msg_N
7863 Nam);
7864 else
7865 Error_Msg_N
7867 Nam);
7870 -- Add friendly warning if initialization comes from a packed array
7871 -- component.
7874 declare
7877 begin
7882 then
7886 then
7887 Error_Msg_NE
7892 else
7899 Error_Msg_N
7902 Nam);