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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) 1992-2019, 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 ------------------------------------------------------------------------------
74 -----------------------
75 -- Local Subprograms --
76 -----------------------
79 -- Typ is a type that is being frozen. If no size clause is given,
80 -- but a default Esize has been computed, then this default Esize is
81 -- adjusted up if necessary to be consistent with a given alignment,
82 -- but never to a value greater than Long_Long_Integer'Size. This
83 -- is used for all discrete types and for fixed-point types.
85 procedure Build_And_Analyze_Renamed_Body
89 -- Build body for a renaming declaration, insert in tree and analyze
92 -- Apply legality checks to address clauses for object declarations,
93 -- at the point the object is frozen. Also ensure any initialization is
94 -- performed only after the object has been frozen.
96 procedure Check_Component_Storage_Order
101 -- For an Encl_Type that has a Scalar_Storage_Order attribute definition
102 -- clause, verify that the component type has an explicit and compatible
103 -- attribute/aspect. For arrays, Comp is Empty; for records, it is the
104 -- entity of the component under consideration. For an Encl_Type that
105 -- does not have a Scalar_Storage_Order attribute definition clause,
106 -- verify that the component also does not have such a clause.
107 -- ADC is the attribute definition clause if present (or Empty). On return,
108 -- Comp_ADC_Present is set True if the component has a Scalar_Storage_Order
109 -- attribute definition clause.
112 -- As each entity is frozen, this routine is called to deal with the
113 -- setting of Debug_Info_Needed for the entity. This flag is set if
114 -- the entity comes from source, or if we are in Debug_Generated_Code
115 -- mode or if the -gnatdV debug flag is set. However, it never sets
116 -- the flag if Debug_Info_Off is set. This procedure also ensures that
117 -- subsidiary entities have the flag set as required.
120 -- When an expression function is frozen by a use of it, the expression
121 -- itself is frozen. Check that the expression does not include references
122 -- to deferred constants without completion. We report this at the freeze
123 -- point of the function, to provide a better error message.
124 --
125 -- In most cases the expression itself is frozen by the time the function
126 -- itself is frozen, because the formals will be frozen by then. However,
127 -- Attribute references to outer types are freeze points for those types;
128 -- this routine generates the required freeze nodes for them.
131 -- For a tagged derived type, create wrappers for inherited operations
132 -- that have a class-wide condition, so it can be properly rewritten if
133 -- it involves calls to other overriding primitives.
136 -- E is a base type. If E is tagged or has a component that is aliased
137 -- or tagged or contains something this is aliased or tagged, set
138 -- Strict_Alignment.
142 -- If E is a fixed-point or discrete type, then all the necessary work
143 -- to freeze it is completed except for possible setting of the flag
144 -- Is_Unsigned_Type, which is done by this procedure. The call has no
145 -- effect if the entity E is not a discrete or fixed-point type.
147 procedure Freeze_And_Append
151 -- Freezes Ent using Freeze_Entity, and appends the resulting list of
152 -- nodes to Result, modifying Result from No_List if necessary. N has
153 -- the same usage as in Freeze_Entity.
156 -- Freeze enumeration type. The Esize field is set as processing
157 -- proceeds (i.e. set by default when the type is declared and then
158 -- adjusted by rep clauses. What this procedure does is to make sure
159 -- that if a foreign convention is specified, and no specific size
160 -- is given, then the size must be at least Integer'Size.
163 -- If an object is frozen which has Is_Statically_Allocated set, then
164 -- all referenced types must also be marked with this flag. This routine
165 -- is in charge of meeting this requirement for the object entity E.
168 -- Perform freezing actions for a subprogram (create extra formals,
169 -- and set proper default mechanism values). Note that this routine
170 -- is not called for internal subprograms, for which neither of these
171 -- actions is needed (or desirable, we do not want for example to have
172 -- these extra formals present in initialization procedures, where they
173 -- would serve no purpose). In this call E is either a subprogram or
174 -- a subprogram type (i.e. an access to a subprogram).
177 -- True if T is not private and has no private components, or has a full
178 -- view. Used to determine whether the designated type of an access type
179 -- should be frozen when the access type is frozen. This is done when an
180 -- allocator is frozen, or an expression that may involve attributes of
181 -- the designated type. Otherwise freezing the access type does not freeze
182 -- the designated type.
184 procedure Process_Default_Expressions
187 -- This procedure is called for each subprogram to complete processing of
188 -- default expressions at the point where all types are known to be frozen.
189 -- The expressions must be analyzed in full, to make sure that all error
190 -- processing is done (they have only been preanalyzed). If the expression
191 -- is not an entity or literal, its analysis may generate code which must
192 -- not be executed. In that case we build a function body to hold that
193 -- code. This wrapper function serves no other purpose (it used to be
194 -- called to evaluate the default, but now the default is inlined at each
195 -- point of call).
198 -- Typ is a record or array type that is being frozen. This routine sets
199 -- the default component alignment from the scope stack values if the
200 -- alignment is otherwise not specified.
203 -- T is a record or array type that is being frozen. If it is a base type,
204 -- and if SSO_Set_Low/High_By_Default is set, then Reverse_Storage order
205 -- will be set appropriately. Note that an explicit occurrence of aspect
206 -- Scalar_Storage_Order or an explicit setting of this aspect with an
207 -- attribute definition clause occurs, then these two flags are reset in
208 -- any case, so call will have no effect.
211 -- T is a type of a component that we know to be an Itype. We don't want
212 -- this to have a Freeze_Node, so ensure it doesn't. Do the same for any
213 -- Full_View or Corresponding_Record_Type.
216 -- Expr is the expression for an address clause for entity Nam whose type
217 -- is Typ. If Typ has a default initialization, and there is no explicit
218 -- initialization in the source declaration, check whether the address
219 -- clause might cause overlaying of an entity, and emit a warning on the
220 -- side effect that the initialization will cause.
222 -------------------------------
223 -- Adjust_Esize_For_Alignment --
224 -------------------------------
229 begin
235 then
241 ------------------------------------
242 -- Build_And_Analyze_Renamed_Body --
243 ------------------------------------
245 procedure Build_And_Analyze_Renamed_Body
249 is
255 begin
256 -- If the renamed subprogram is intrinsic, there is no need for a
257 -- wrapper body: we set the alias that will be called and expanded which
258 -- completes the declaration. This transformation is only legal if the
259 -- renamed entity has already been elaborated.
261 -- Note that it is legal for a renaming_as_body to rename an intrinsic
262 -- subprogram, as long as the renaming occurs before the new entity
263 -- is frozen (RM 8.5.4 (5)).
267 then
269 else
275 and then
279 -- We can make the renaming entity intrinsic if the renamed function
280 -- has an interface name, or if it is one of the shift/rotate
281 -- operations known to the compiler.
283 and then
286 Name_Rotate_Right,
287 Name_Shift_Left,
288 Name_Shift_Right,
289 Name_Shift_Right_Arithmetic))
290 then
295 else
302 else
311 ------------------------
312 -- Build_Renamed_Body --
313 ------------------------
315 function Build_Renamed_Body
318 is
320 -- We use for the source location of the renamed body, the location of
321 -- the spec entity. It might seem more natural to use the location of
322 -- the renaming declaration itself, but that would be wrong, since then
323 -- the body we create would look as though it was created far too late,
324 -- and this could cause problems with elaboration order analysis,
325 -- particularly in connection with instantiations.
340 -- If the renamed entity is a primitive operation given in prefix form,
341 -- the prefix is the target object and it has to be added as the first
342 -- actual in the generated call.
344 begin
345 -- Determine the entity being renamed, which is the target of the call
346 -- statement. If the name is an explicit dereference, this is a renaming
347 -- of a subprogram type rather than a subprogram. The name itself is
348 -- fully analyzed.
359 else
366 else
372 -- If the renamed entity is a predefined operator, retain full name
373 -- to ensure its visibility.
377 then
379 else
383 else
386 and then
389 then
391 -- Retrieve the target object, to be added as a first actual
392 -- in the call.
397 else
401 -- Original name may have been overloaded, but is fully resolved now
406 -- For simple renamings, subsequent calls can be expanded directly as
407 -- calls to the renamed entity. The body must be generated in any case
408 -- for calls that may appear elsewhere. This is not done in the case
409 -- where the subprogram is an instantiation because the actual proper
410 -- body has not been built yet.
415 then
419 -- Check whether the return type is a limited view. If the subprogram
420 -- is already frozen the generated body may have a non-limited view
421 -- of the type, that must be used, because it is the one in the spec
422 -- of the renaming declaration.
426 then
427 declare
429 begin
431 Set_Result_Definition
437 -- The body generated for this renaming is an internal artifact, and
438 -- does not constitute a freeze point for the called entity.
445 declare
449 begin
450 -- The controlling formal may be an access parameter, or the
451 -- actual may be an access value, so adjust accordingly.
455 then
456 Actuals := New_List
461 then
462 Actuals :=
463 New_List (
467 else
475 else
486 -- If the renamed entity is an entry, inherit its profile. For other
487 -- renamings as bodies, both profiles must be subtype conformant, so it
488 -- is not necessary to replace the profile given in the declaration.
489 -- However, default values that are aggregates are rewritten when
490 -- partially analyzed, so we recover the original aggregate to insure
491 -- that subsequent conformity checking works. Similarly, if the default
492 -- expression was constant-folded, recover the original expression.
502 N_Access_Definition
503 then
511 then
522 -- If the renamed entity is a function, the generated body contains a
523 -- return statement. Otherwise, build a procedure call. If the entity is
524 -- an entry, subsequent analysis of the call will transform it into the
525 -- proper entry or protected operation call. If the renamed entity is
526 -- a character literal, return it directly.
532 then
533 Call_Node :=
535 Expression =>
541 Call_Node :=
546 Call_Node :=
549 else
550 Call_Node :=
556 -- Create entities for subprogram body and formals
569 Body_Node :=
573 Handled_Statement_Sequence =>
583 -- Link the body to the entity whose declaration it completes. If
584 -- the body is analyzed when the renamed entity is frozen, it may
585 -- be necessary to restore the proper scope (see package Exp_Ch13).
589 then
591 else
598 --------------------------
599 -- Check_Address_Clause --
600 --------------------------
611 begin
614 -- For a deferred constant, the initialization value is on full view
618 else
627 -- Has_Delayed_Freeze was set on E when the address clause was
628 -- analyzed, and must remain set because we want the address
629 -- clause to be elaborated only after any entity it references
630 -- has been elaborated.
633 -- If Rep_Clauses are to be ignored, remove address clause from
634 -- list attached to entity, because it may be illegal for gigi,
635 -- for example by breaking order of elaboration..
638 declare
641 begin
647 else
650 loop
660 -- And now remove the address clause
666 then
672 -- If a variable, or a non-imported constant, overlays a constant
673 -- object and has an initialization value, then the initialization
674 -- may end up writing into read-only memory. Detect the cases of
675 -- statically identical values and remove the initialization. In
676 -- the other cases, give a warning. We will give other warnings
677 -- later for the variable if it is assigned.
684 then
685 declare
689 begin
695 and then Compile_Time_Compare
699 then
704 and then Address_Clause_Overlay_Warnings
705 then
707 Error_Msg_NE
714 -- Remove side effects from initial expression, except in the case of
715 -- limited build-in-place calls and aggregates, which have their own
716 -- expansion elsewhere. This exception is necessary to avoid copying
717 -- limited objects.
721 -- Capture initialization value at point of declaration, and make
722 -- explicit assignment legal, because object may be a constant.
728 -- Move initialization to freeze actions, once the object has
729 -- been frozen and the address clause alignment check has been
730 -- performed.
739 -- If the object is tagged, check whether the tag must be
740 -- reassigned explicitly.
750 -----------------------------
751 -- Check_Compile_Time_Size --
752 -----------------------------
757 -- Sets the compile time known size (64 bits or less) in the RM_Size
758 -- field of T, checking for a size clause that was given which attempts
759 -- to give a smaller size.
762 -- Recursive function that does all the work
765 -- If T is a constrained subtype, its size is not known if any of its
766 -- discriminant constraints is not static and it is not a null record.
767 -- The test is conservative and doesn't check that the components are
768 -- in fact constrained by non-static discriminant values. Could be made
769 -- more precise ???
771 --------------------
772 -- Set_Small_Size --
773 --------------------
776 begin
780 -- Check for bad size clause given
785 Error_Msg_NE
790 -- Set size if not set already
797 ----------------
798 -- Size_Known --
799 ----------------
808 begin
812 -- Always True for elementary types, even generic formal elementary
813 -- types. We used to return False in the latter case, but the size
814 -- is known at compile time, even in the template, we just do not
815 -- know the exact size but that's not the point of this routine.
820 -- Array types
824 -- String literals always have known size, and we can set it
827 Set_Small_Size
831 -- Unconstrained types never have known at compile time size
836 -- Don't do any recursion on type with error posted, since we may
837 -- have a malformed type that leads us into a loop.
842 -- Otherwise if component size unknown, then array size unknown
848 -- Check for all indexes static, and also compute possible size
849 -- (in case it is not greater than 64 and may be packable).
851 declare
855 begin
864 else
872 then
875 else
880 else
892 -- For non-generic private types, go to underlying type if present
897 then
898 -- Don't do any recursion on type with error posted, since we may
899 -- have a malformed type that leads us into a loop.
903 else
907 -- Record types
911 -- A class-wide type is never considered to have a known size
916 -- A subtype of a variant record must not have non-static
917 -- discriminated components.
921 then
924 -- Don't do any recursion on type with error posted, since we may
925 -- have a malformed type that leads us into a loop.
931 -- Now look at the components of the record
933 declare
934 -- The following two variables are used to keep track of the
935 -- size of packed records if we can tell the size of the packed
936 -- record in the front end. Packed_Size_Known is True if so far
937 -- we can figure out the size. It is initialized to True for a
938 -- packed record, unless the record has discriminants or atomic
939 -- components or independent components.
941 -- The reason we eliminate the discriminated case is that
942 -- we don't know the way the back end lays out discriminated
943 -- packed records. If Packed_Size_Known is True, then
944 -- Packed_Size is the size in bits so far.
953 -- Size in bits so far
955 begin
956 -- Test for variant part present
962 N_Record_Definition
964 and then
965 Present (Variant_Part
967 then
968 -- If variant part is present, and type is unconstrained,
969 -- then we must have defaulted discriminants, or a size
970 -- clause must be present for the type, or else the size
971 -- is definitely not known at compile time.
974 and then
977 then
982 -- Loop through components
988 -- We do not know the packed size if there is a component
989 -- clause present (we possibly could, but this would only
990 -- help in the case of a record with partial rep clauses.
991 -- That's because in the case of full rep clauses, the
992 -- size gets figured out anyway by a different circuit).
998 -- We do not know the packed size for an atomic/VFA type
999 -- or component, or an independent type or component, or a
1000 -- by-reference type or aliased component (because packing
1001 -- does not touch these).
1009 then
1013 -- We need to identify a component that is an array where
1014 -- the index type is an enumeration type with non-standard
1015 -- representation, and some bound of the type depends on a
1016 -- discriminant.
1018 -- This is because gigi computes the size by doing a
1019 -- substitution of the appropriate discriminant value in
1020 -- the size expression for the base type, and gigi is not
1021 -- clever enough to evaluate the resulting expression (which
1022 -- involves a call to rep_to_pos) at compile time.
1024 -- It would be nice if gigi would either recognize that
1025 -- this expression can be computed at compile time, or
1026 -- alternatively figured out the size from the subtype
1027 -- directly, where all the information is at hand ???
1031 then
1032 declare
1040 begin
1047 then
1053 then
1058 then
1068 -- Clearly size of record is not known if the size of one of
1069 -- the components is not known.
1075 -- Accumulate packed size if possible
1079 -- We can deal with elementary types, small packed arrays
1080 -- if the representation is a modular type and also small
1081 -- record types (if the size is not greater than 64, but
1082 -- the condition is checked by Set_Small_Size).
1086 and then Present
1088 and then Is_Modular_Integer_Type
1091 then
1092 -- If RM_Size is known and static, then we can keep
1093 -- accumulating the packed size.
1099 -- If we have a field whose RM_Size is not known then
1100 -- we can't figure out the packed size here.
1102 else
1106 -- For other types we can't figure out the packed size
1108 else
1123 -- All other cases, size not known at compile time
1125 else
1130 -------------------------------------
1131 -- Static_Discriminated_Components --
1132 -------------------------------------
1134 function Static_Discriminated_Components
1136 is
1139 begin
1143 then
1157 -- Start of processing for Check_Compile_Time_Size
1159 begin
1163 -----------------------------------
1164 -- Check_Component_Storage_Order --
1165 -----------------------------------
1167 procedure Check_Component_Storage_Order
1172 is
1181 -- Set for the record case, True if Comp is aligned on byte boundaries
1182 -- (in which case it is allowed to have different storage order).
1185 -- Set True when the component is a nested composite, and it does not
1186 -- have the same scalar storage order as Encl_Type.
1188 begin
1189 -- Record case
1199 else
1200 -- If a component clause is present, check if the component starts
1201 -- and ends on byte boundaries. Otherwise conservatively assume it
1202 -- does so only in the case where the record is not packed.
1205 Comp_Byte_Aligned :=
1207 and then
1209 else
1216 -- Array case
1218 else
1225 -- Note: the Reverse_Storage_Order flag is set on the base type, but
1226 -- the attribute definition clause is attached to the first subtype.
1227 -- Also, if the base type is incomplete or private, go to full view
1228 -- if known
1240 Comp_ADC :=
1241 Get_Attribute_Definition_Clause
1245 -- Case of record or array component: check storage order compatibility.
1246 -- But, if the record has Complex_Representation, then it is treated as
1247 -- a scalar in the back end so the storage order is irrelevant.
1252 then
1253 Comp_SSO_Differs :=
1257 -- Parent and extension must have same storage order
1261 Error_Msg_N
1266 -- If component and composite SSO differs, check that component
1267 -- falls on byte boundaries and isn't bit packed.
1271 -- Component SSO differs from enclosing composite:
1273 -- Reject if composite is a bit-packed array, as it is rewritten
1274 -- into an array of scalars.
1277 Error_Msg_N
1281 -- Reject if not byte aligned
1284 and then not Comp_Byte_Aligned
1285 then
1286 Error_Msg_N
1290 -- Warn if specified only for the outer composite
1293 Error_Msg_NE
1299 -- Enclosing type has explicit SSO: non-composite component must not
1300 -- be aliased.
1303 Error_Msg_N
1309 -----------------------------
1310 -- Check_Debug_Info_Needed --
1311 -----------------------------
1314 begin
1319 or else Debug_Generated_Code
1320 or else Debug_Flag_VV
1322 then
1327 -------------------------------
1328 -- Check_Expression_Function --
1329 -------------------------------
1333 -- Function to search for deferred constant
1335 -------------------
1336 -- Find_Constant --
1337 -------------------
1340 begin
1341 -- When a constant is initialized with the result of a dispatching
1342 -- call, the constant declaration is rewritten as a renaming of the
1343 -- displaced function result. This scenario is not a premature use of
1344 -- a constant even though the Has_Completion flag is not set.
1351 N_Object_Declaration
1355 then
1356 Error_Msg_NE
1364 then
1374 -- Local variables
1378 -- Start of processing for Check_Expression_Function
1380 begin
1383 -- The subprogram body created for the expression function is not
1384 -- itself a freeze point.
1389 then
1394 --------------------------------
1395 -- Check_Inherited_Conditions --
1396 --------------------------------
1407 -- Build corresponding pragmas for an operation whose ancestor has
1408 -- class-wide pre/postconditions. If the operation is inherited, the
1409 -- pragmas force the creation of a wrapper for the inherited operation.
1410 -- If the ancestor is being overridden, the pragmas are constructed only
1411 -- to verify their legality, in case they contain calls to other
1412 -- primitives that may haven been overridden.
1414 ---------------------------------------
1415 -- Build_Inherited_Condition_Pragmas --
1416 ---------------------------------------
1423 begin
1428 Build_Class_Wide_Expression
1435 if Needs_Wrapper
1437 and then Expander_Active
1438 then
1447 Build_Class_Wide_Expression
1454 if Needs_Wrapper
1456 and then Expander_Active
1457 then
1463 -- Start of processing for Check_Inherited_Conditions
1465 begin
1470 -- Map the overridden primitive to the overriding one. This takes
1471 -- care of all overridings and is done only once.
1475 then
1483 -- Perform validity checks on the inherited conditions of overriding
1484 -- operations, for conformance with LSP, and apply SPARK-specific
1485 -- restrictions on inherited conditions.
1493 then
1496 -- Analyze the contract items of the overridden operation, before
1497 -- they are rewritten as pragmas.
1501 -- In GNATprove mode this is where we can collect the inherited
1502 -- conditions, because we do not create the Check pragmas that
1503 -- normally convey the the modified class-wide conditions on
1504 -- overriding operations.
1509 -- Otherwise build the corresponding pragmas to check for legality
1510 -- of the inherited condition.
1512 else
1520 -- Now examine the inherited operations to check whether they require
1521 -- a wrapper to handle inherited conditions that call other primitives,
1522 -- so that LSP can be verified/enforced.
1534 -- Analyze the contract items of the parent operation, and
1535 -- determine whether a wrapper is needed. This is determined
1536 -- when the condition is rewritten in sem_prag, using the
1537 -- mapping between overridden and overriding operations built
1538 -- in the loop above.
1544 if Needs_Wrapper
1546 and then Expander_Active
1547 then
1548 -- We need to build a new primitive that overrides the inherited
1549 -- one, and whose inherited expression has been updated above.
1550 -- These expressions are the arguments of pragmas that are part
1551 -- of the declarations of the wrapper. The wrapper holds a single
1552 -- statement that is a call to the class-wide clone, where the
1553 -- controlling actuals are conversions to the corresponding type
1554 -- in the parent primitive:
1556 -- procedure New_Prim (F1 : T1; ...);
1557 -- procedure New_Prim (F1 : T1; ...) is
1558 -- pragma Check (Precondition, Expr);
1559 -- begin
1560 -- Par_Prim_Clone (Par_Type (F1), ...);
1561 -- end;
1563 -- If the primitive is a function the statement is a return
1564 -- statement with a call.
1566 declare
1573 begin
1575 New_Decl :=
1579 -- Insert the declaration and the body of the wrapper after
1580 -- type declaration that generates inherited operation. For
1581 -- a null procedure, the declaration implies a null body.
1585 then
1588 else
1589 -- Build body as wrapper to a call to the already built
1590 -- class-wide clone.
1592 New_Body :=
1593 Build_Class_Wide_Clone_Call
1596 Insert_List_After_And_Analyze
1608 ----------------------------
1609 -- Check_Strict_Alignment --
1610 ----------------------------
1615 begin
1633 then
1643 -------------------------
1644 -- Check_Unsigned_Type --
1645 -------------------------
1652 begin
1657 -- Do not attempt to analyze case where range was in error
1663 -- The situation that is nontrivial is something like:
1665 -- subtype x1 is integer range -10 .. +10;
1666 -- subtype x2 is x1 range 0 .. V1;
1667 -- subtype x3 is x2 range V2 .. V3;
1668 -- subtype x4 is x3 range V4 .. V5;
1670 -- where Vn are variables. Here the base type is signed, but we still
1671 -- know that x4 is unsigned because of the lower bound of x2.
1673 -- The only way to deal with this is to look up the ancestor chain
1676 loop
1690 else
1693 -- If no ancestor had a static lower bound, go to base type
1697 -- Note: the reason we still check for a compile time known
1698 -- value for the base type is that at least in the case of
1699 -- generic formals, we can have bounds that fail this test,
1700 -- and there may be other cases in error situations.
1712 then
1722 -----------------------------
1723 -- Is_Atomic_VFA_Aggregate --
1724 -----------------------------
1733 begin
1736 -- Array may be qualified, so find outer context
1753 then
1762 then
1771 New_N :=
1783 -----------------------------------------------
1784 -- Explode_Initialization_Compound_Statement --
1785 -----------------------------------------------
1790 begin
1793 then
1796 -- Note that we rewrite Init_Stmts into a NULL statement, rather than
1797 -- just removing it, because Freeze_All may rely on this particular
1798 -- Node_Id still being present in the enclosing list to know where to
1799 -- stop freezing.
1807 ----------------
1808 -- Freeze_All --
1809 ----------------
1811 -- Note: the easy coding for this procedure would be to just build a
1812 -- single list of freeze nodes and then insert them and analyze them
1813 -- all at once. This won't work, because the analysis of earlier freeze
1814 -- nodes may recursively freeze types which would otherwise appear later
1815 -- on in the freeze list. So we must analyze and expand the freeze nodes
1816 -- as they are generated.
1820 -- This is the internal recursive routine that does freezing of entities
1821 -- (but NOT the analysis of default expressions, which should not be
1822 -- recursive, we don't want to analyze those till we are sure that ALL
1823 -- the types are frozen).
1825 --------------------
1826 -- Freeze_All_Ent --
1827 --------------------
1835 -- If freeze nodes are present, insert and analyze, and reset cursor
1836 -- for next insertion.
1838 -------------------
1839 -- Process_Flist --
1840 -------------------
1843 begin
1850 else
1856 -- Start of processing for Freeze_All_Ent
1858 begin
1862 -- If the entity is an inner package which is not a package
1863 -- renaming, then its entities must be frozen at this point. Note
1864 -- that such entities do NOT get frozen at the end of the nested
1865 -- package itself (only library packages freeze).
1867 -- Same is true for task declarations, where anonymous records
1868 -- created for entry parameters must be frozen.
1874 then
1885 then
1892 N_Task_Type_Declaration)
1893 then
1896 End_Scope;
1898 -- For a derived tagged type, we must ensure that all the
1899 -- primitive operations of the parent have been frozen, so that
1900 -- their addresses will be in the parent's dispatch table at the
1901 -- point it is inherited.
1907 then
1908 declare
1915 begin
1922 then
1924 Process_Flist;
1934 Process_Flist;
1936 -- If already frozen, and there are delayed aspects, this is where
1937 -- we do the visibility check for these aspects (see Sem_Ch13 spec
1938 -- for a description of how we handle aspect visibility).
1941 declare
1944 begin
1950 then
1959 -- If an incomplete type is still not frozen, this may be a
1960 -- premature freezing because of a body declaration that follows.
1961 -- Indicate where the freezing took place. Freezing will happen
1962 -- if the body comes from source, but not if it is internally
1963 -- generated, for example as the body of a type invariant.
1965 -- If the freezing is caused by the end of the current declarative
1966 -- part, it is a Taft Amendment type, and there is no error.
1970 then
1971 declare
1974 begin
1975 -- The presence of a body freezes all entities previously
1976 -- declared in the current list of declarations, but this
1977 -- does not apply if the body does not come from source.
1978 -- A type invariant is transformed into a subprogram body
1979 -- which is placed at the end of the private part of the
1980 -- current package, but this body does not freeze incomplete
1981 -- types that may be declared in this private part.
1984 N_Package_Body,
1985 N_Protected_Body,
1986 N_Subprogram_Body,
1987 N_Task_Body)
1989 and then
1992 then
1994 Error_Msg_NE
2005 -- Local variables
2011 -- Start of processing for Freeze_All
2013 begin
2016 -- Now that all types are frozen, we can deal with default expressions
2017 -- that require us to build a default expression functions. This is the
2018 -- point at which such functions are constructed (after all types that
2019 -- might be used in such expressions have been frozen).
2021 -- For subprograms that are renaming_as_body, we create the wrapper
2022 -- bodies as needed.
2024 -- We also add finalization chains to access types whose designated
2025 -- types are controlled. This is normally done when freezing the type,
2026 -- but this misses recursive type definitions where the later members
2027 -- of the recursion introduce controlled components.
2029 -- Loop through entities
2044 else
2050 and then
2052 N_Subprogram_Renaming_Declaration
2053 then
2054 Build_And_Analyze_Renamed_Body
2059 -- Freeze the default expressions of entries, entry families, and
2060 -- protected subprograms.
2067 then
2075 -- Historical note: We used to create a finalization master for an
2076 -- access type whose designated type is not controlled, but contains
2077 -- private controlled compoments. This form of postprocessing is no
2078 -- longer needed because the finalization master is now created when
2079 -- the access type is frozen (see Exp_Ch3.Freeze_Type).
2085 -----------------------
2086 -- Freeze_And_Append --
2087 -----------------------
2089 procedure Freeze_And_Append
2093 is
2095 begin
2099 else
2105 -------------------
2106 -- Freeze_Before --
2107 -------------------
2109 procedure Freeze_Before
2113 is
2114 -- Freeze T, then insert the generated Freeze nodes before the node N.
2115 -- Flag Freeze_Profile is used when T is an overloadable entity, and
2116 -- indicates whether its profile should be frozen at the same time.
2122 begin
2129 -- If the entity is a type declared in an inner package, it may be
2130 -- frozen by an outer declaration before the package itself is
2131 -- frozen. Install the package scope to analyze the freeze nodes,
2132 -- which may include generated subprograms such as predicate
2133 -- functions, etc.
2142 else
2148 -------------------
2149 -- Freeze_Entity --
2150 -------------------
2152 -- WARNING: This routine manages Ghost regions. Return statements must be
2153 -- replaced by gotos which jump to the end of the routine and restore the
2154 -- Ghost mode.
2156 function Freeze_Entity
2160 is
2165 -- Save the Ghost-related attributes to restore on exit
2174 -- List of freezing actions, left at No_List if none
2177 -- This could use a comment ???
2180 -- Add freeze action Fnod to list Result
2183 -- If Loc is a freeze_entity that appears after the last declaration
2184 -- in the scope, inhibit error messages on late completion.
2187 -- Check that an Access or Unchecked_Access attribute with a prefix
2188 -- which is the current instance type can only be applied when the type
2189 -- is limited.
2192 -- Give a warning for pragma Convention with language C or C++ applied
2193 -- to a discriminated record type. This is suppressed for the unchecked
2194 -- union case, since the whole point in this case is interface C. We
2195 -- also do not generate this within instantiations, since we will have
2196 -- generated a message on the template.
2199 -- Give warning for modulus of 8, 16, 32, or 64 given as an explicit
2200 -- integer literal without an explicit corresponding size clause. The
2201 -- caller has checked that Utype is a modular integer type.
2204 -- Freeze array type, including freezing index and component types
2207 -- Perform checks and generate freeze node if needed for a constant or
2208 -- variable declared by an object declaration.
2211 -- Create Freeze_Generic_Entity nodes for types declared in a generic
2212 -- package. Recurse on inner generic packages.
2215 -- Freeze formals and return type of subprogram. If some type in the
2216 -- profile is incomplete and we are in an instance, freezing of the
2217 -- entity will take place elsewhere, and the function returns False.
2220 -- Freeze record type, including freezing component types, and freezing
2221 -- primitive operations if this is a tagged type.
2224 -- Determine whether an arbitrary entity is subject to Boolean aspect
2225 -- Import and its value is specified as True.
2227 procedure Inherit_Freeze_Node
2230 -- Set type Typ's freeze node to refer to Fnode. This routine ensures
2231 -- that any attributes attached to Typ's original node are preserved.
2234 -- If E is an entity for an imported subprogram with pre/post-conditions
2235 -- then this procedure will create a wrapper to ensure that proper run-
2236 -- time checking of the pre/postconditions. See body for details.
2238 -------------------
2239 -- Add_To_Result --
2240 -------------------
2243 begin
2247 ----------------------------
2248 -- After_Last_Declaration --
2249 ----------------------------
2254 begin
2260 else
2264 else
2269 ----------------------------
2270 -- Check_Current_Instance --
2271 ----------------------------
2276 -- Determine whether Typ is compatible with the rules for aliased
2277 -- views of types as defined in RM 3.10 in the various dialects.
2280 -- Process routine to apply check to given node
2282 -----------------------------
2283 -- Is_Aliased_View_Of_Type --
2284 -----------------------------
2289 begin
2290 -- Common case
2294 then
2297 -- The following paragraphs describe what a legal aliased view of
2298 -- a type is in the various dialects of Ada.
2300 -- Ada 95
2302 -- The current instance of a limited type, and a formal parameter
2303 -- or generic formal object of a tagged type.
2305 -- Ada 95 limited type
2306 -- * Type with reserved word "limited"
2307 -- * A protected or task type
2308 -- * A composite type with limited component
2313 -- Ada 2005
2315 -- The current instance of a limited tagged type, a protected
2316 -- type, a task type, or a type that has the reserved word
2317 -- "limited" in its full definition ... a formal parameter or
2318 -- generic formal object of a tagged type.
2320 -- Ada 2005 limited type
2321 -- * Type with reserved word "limited", "synchronized", "task"
2322 -- or "protected"
2323 -- * A composite type with limited component
2324 -- * A derived type whose parent is a non-interface limited type
2327 return
2329 or else
2334 -- Ada 2012 and beyond
2336 -- The current instance of an immutably limited type ... a formal
2337 -- parameter or generic formal object of a tagged type.
2339 -- Ada 2012 limited type
2340 -- * Type with reserved word "limited", "synchronized", "task"
2341 -- or "protected"
2342 -- * A composite type with limited component
2343 -- * A derived type whose parent is a non-interface limited type
2344 -- * An incomplete view
2346 -- Ada 2012 immutably limited type
2347 -- * Explicitly limited record type
2348 -- * Record extension with "limited" present
2349 -- * Non-formal limited private type that is either tagged
2350 -- or has at least one access discriminant with a default
2351 -- expression
2352 -- * Task type, protected type or synchronized interface
2353 -- * Type derived from immutably limited type
2355 else
2356 return
2362 -------------
2363 -- Process --
2364 -------------
2367 begin
2371 Name_Unchecked_Access)
2375 then
2377 Error_Msg_N
2380 else
2381 Error_Msg_N
2388 else
2399 -- Local variables
2404 -- Start of processing for Check_Current_Instance
2406 begin
2412 ---------------------------------
2413 -- Check_Suspicious_Convention --
2414 ---------------------------------
2417 begin
2422 or else
2425 and then not In_Instance
2427 then
2428 declare
2433 begin
2438 Error_Msg_N
2441 else
2442 Error_Msg_N
2447 Error_Msg_NE
2455 ------------------------------
2456 -- Check_Suspicious_Modulus --
2457 ------------------------------
2462 begin
2468 declare
2471 begin
2473 declare
2477 begin
2479 declare
2483 begin
2484 -- First case, modulus and size are the same. This
2485 -- happens if you have something like mod 32, with
2486 -- an explicit size of 32, this is for sure a case
2487 -- where the warning is given, since it is seems
2488 -- very unlikely that someone would want e.g. a
2489 -- five bit type stored in 32 bits. It is much
2490 -- more likely they wanted a 32-bit type.
2495 -- Second case, the modulus is 32 or 64 and no
2496 -- size clause is present. This is a less clear
2497 -- case for giving the warning, but in the case
2498 -- of 32/64 (5-bit or 6-bit types) these seem rare
2499 -- enough that it is a likely error (and in any
2500 -- case using 2**5 or 2**6 in these cases seems
2501 -- clearer. We don't include 8 or 16 here, simply
2502 -- because in practice 3-bit and 4-bit types are
2503 -- more common and too many false positives if
2504 -- we warn in these cases.
2508 then
2511 -- No warning needed
2513 else
2517 -- If we fall through, give warning
2520 Error_Msg_N
2522 Modulus);
2531 -----------------------
2532 -- Freeze_Array_Type --
2533 -----------------------
2541 -- Set true if any of the index types is an enumeration type with a
2542 -- non-standard representation.
2544 begin
2553 then
2560 -- Processing that is done only for base types
2564 -- Deal with default setting of reverse storage order
2568 -- Propagate flags for component type
2572 then
2580 -- The array type requires its own invariant procedure in order to
2581 -- verify the component invariant over all elements. In GNATprove
2582 -- mode, the component invariants are checked by other means. They
2583 -- should not be added to the array type invariant procedure, so
2584 -- that the procedure can be used to check the array type
2585 -- invariants if any.
2588 and then not GNATprove_Mode
2589 then
2592 -- The array type is an implementation base type. Propagate the
2593 -- same property to the first subtype.
2600 -- Warn for pragma Pack overriding foreign convention
2604 then
2605 declare
2610 begin
2614 Error_Msg_N
2617 Error_Msg_N
2624 -- If packing was requested or if the component size was
2625 -- set explicitly, then see if bit packing is required. This
2626 -- processing is only done for base types, since all of the
2627 -- representation aspects involved are type-related.
2629 -- This is not just an optimization, if we start processing the
2630 -- subtypes, they interfere with the settings on the base type
2631 -- (this is because Is_Packed has a slightly different meaning
2632 -- before and after freezing).
2634 declare
2638 begin
2642 then
2651 else
2654 -- We can set the component size if it is less than 16,
2655 -- rounding it up to the next storage unit size.
2661 else
2665 -- Set component size up to match alignment if it would
2666 -- otherwise be less than the alignment. This deals with
2667 -- cases of types whose alignment exceeds their size (the
2668 -- padded type cases).
2671 declare
2673 begin
2681 -- Case of component size that may result in bit packing
2684 declare
2690 Get_Attribute_Definition_Clause
2693 begin
2694 -- Warn if we have pack and component size so that the
2695 -- pack is ignored.
2697 -- Note: here we must check for the presence of a
2698 -- component size before checking for a Pack pragma to
2699 -- deal with the case where the array type is a derived
2700 -- type whose parent is currently private.
2704 and then Warn_On_Redundant_Constructs
2705 then
2707 Error_Msg_NE
2709 Error_Msg_N
2715 -- Set component size if not already set by a component
2716 -- size clause.
2722 -- Check for base type of 8, 16, 32 bits, where an
2723 -- unsigned subtype has a length one less than the
2724 -- base type (e.g. Natural subtype of Integer).
2726 -- In such cases, if a component size was not set
2727 -- explicitly, then generate a warning.
2733 then
2737 Error_Msg_N
2739 Pack_Pragma);
2740 Error_Msg_N
2742 Pack_Pragma);
2746 -- Bit packing is never needed for 8, 16, 32, 64
2750 -- If the Esize of the component is known and equal to
2751 -- the component size then even packing is not needed.
2755 then
2756 -- Here the array was requested to be packed, but
2757 -- the packing request had no effect whatsoever,
2758 -- so flag Is_Packed is reset.
2760 -- Note: semantically this means that we lose track
2761 -- of the fact that a derived type inherited pragma
2762 -- Pack that was non-effective, but that is fine.
2764 -- We regard a Pack pragma as a request to set a
2765 -- representation characteristic, and this request
2766 -- may be ignored.
2770 else
2777 -- Bit packing is not needed for multiples of the storage
2778 -- unit if the type is composite because the back end can
2779 -- byte pack composite types.
2783 then
2788 -- In all other cases, bit packing is needed
2790 else
2799 -- Check for Aliased or Atomic_Components/Atomic/VFA with
2800 -- unsuitable packing or explicit component size clause given.
2805 and then
2807 then
2811 -- Outputs error messages for incorrect CS clause or pragma
2812 -- Pack for aliased or atomic/VFA components (T is "aliased"
2813 -- or "atomic/vfa");
2815 -----------------
2816 -- Complain_CS --
2817 -----------------
2820 begin
2822 Clause :=
2823 Get_Attribute_Definition_Clause
2826 Error_Msg_N
2830 Error_Msg_N
2833 else
2834 Error_Msg_N
2840 -- Start of processing for Alias_Atomic_Check
2842 begin
2843 -- If object size of component type isn't known, we cannot
2844 -- be sure so we defer to the back end.
2849 -- Case where component size has no effect. First check for
2850 -- object size of component type multiple of the storage
2851 -- unit size.
2855 -- OK in both packing case and component size case if RM
2856 -- size is known and static and same as the object size.
2858 and then
2862 -- Or if we have an explicit component size clause and
2863 -- the component size and object size are equal.
2865 or else
2868 then
2876 then
2885 -- Check for Independent_Components/Independent with unsuitable
2886 -- packing or explicit component size clause given.
2889 and then
2891 then
2892 begin
2893 -- If object size of component type isn't known, we cannot
2894 -- be sure so we defer to the back end.
2899 -- Case where component size has no effect. First check for
2900 -- object size of component type multiple of the storage
2901 -- unit size.
2905 -- OK in both packing case and component size case if RM
2906 -- size is known and multiple of the storage unit size.
2908 and then
2912 -- Or if we have an explicit component size clause and
2913 -- the component size is larger than the object size.
2915 or else
2918 then
2921 else
2923 Clause :=
2924 Get_Attribute_Definition_Clause
2927 Error_Msg_N
2931 Error_Msg_N
2934 else
2935 Error_Msg_N
2943 -- Warn for case of atomic type
2949 then
2950 Error_Msg_NE
2965 -- Check for scalar storage order
2967 declare
2969 begin
2970 Check_Component_Storage_Order
2973 ADC => Get_Attribute_Definition_Clause
2975 Attribute_Scalar_Storage_Order),
2979 -- Processing that is done only for subtypes
2981 else
2982 -- Acquire alignment from base type
2990 -- Specific checks for bit-packed arrays
2994 -- Check number of elements for bit-packed arrays that come from
2995 -- source and have compile time known ranges. The bit-packed
2996 -- arrays circuitry does not support arrays with more than
2997 -- Integer'Last + 1 elements, and when this restriction is
2998 -- violated, causes incorrect data access.
3000 -- For the case where this is not compile time known, a run-time
3001 -- check should be generated???
3004 declare
3010 begin
3016 -- Never generate an error if any index is of a generic
3017 -- type. We will check this in instances.
3024 Ilen :=
3030 -- No attempt is made to check number of elements if not
3031 -- compile time known.
3044 then
3045 Error_Msg_N
3052 -- Check size
3055 declare
3059 begin
3060 -- It is not clear if it is possible to have no size clause
3061 -- at this stage, but it is not worth worrying about. Post
3062 -- error on the entity name in the size clause if present,
3063 -- else on the type entity itself.
3067 else
3074 -- If any of the index types was an enumeration type with a non-
3075 -- standard rep clause, then we indicate that the array type is
3076 -- always packed (even if it is not bit-packed).
3085 -- If the array is packed and bit-packed or packed to eliminate holes
3086 -- in the non-contiguous enumeration index types, we must create the
3087 -- packed array type to be used to actually implement the type. This
3088 -- is only needed for real array types (not for string literal types,
3089 -- since they are present only for the front end).
3094 then
3098 -- Make sure that we have the necessary routines to implement the
3099 -- packing, and complain now if not. Note that we only test this
3100 -- for constrained array types.
3106 then
3107 declare
3111 begin
3114 then
3115 Error_Msg_CRT
3119 -- Cancel the packing
3129 -- Size information of packed array type is copied to the array
3130 -- type, since this is really the representation. But do not
3131 -- override explicit existing size values. If the ancestor subtype
3132 -- is constrained the Packed_Array_Impl_Type will be inherited
3133 -- from it, but the size may have been provided already, and
3134 -- must not be overridden either.
3137 and then
3140 then
3152 -- For non-packed arrays set the alignment of the array to the
3153 -- alignment of the component type if it is unknown. Skip this
3154 -- in atomic/VFA case (atomic/VFA arrays may need larger alignments).
3163 then
3167 -- A Ghost type cannot have a component of protected or task type
3168 -- (SPARK RM 6.9(19)).
3171 Error_Msg_N
3173 Arr);
3177 -------------------------------
3178 -- Freeze_Object_Declaration --
3179 -------------------------------
3183 -- Check that the size of array type Typ can be computed without
3184 -- overflow, and generates a Storage_Error otherwise. This is only
3185 -- relevant for array types whose index is a (mod 2**64) type, where
3186 -- wrap-around arithmetic might yield a meaningless value for the
3187 -- length of the array, or its corresponding attribute.
3190 -- Ensure that the initialization state of variable Var_Id subject
3191 -- to pragma Thread_Local_Storage agrees with the semantics of the
3192 -- pragma.
3194 function Has_Default_Initialization
3196 -- Determine whether object Obj_Id default initialized
3198 -------------------------------
3199 -- Check_Large_Modular_Array --
3200 -------------------------------
3206 begin
3207 -- Nothing to do when expansion is disabled because this routine
3208 -- generates a runtime check.
3213 -- Nothing to do for String literal subtypes because their index
3214 -- cannot be a modular type.
3219 -- Nothing to do for an imported object because the object will
3220 -- be created on the exporting side.
3225 -- Nothing to do for unconstrained array types. This case arises
3226 -- when the object declaration is illegal.
3234 -- To prevent arithmetic overflow with large values, we raise
3235 -- Storage_Error under the following guard:
3236 --
3237 -- (Arr'Last / 2 - Arr'First / 2) > (2 ** 30)
3238 --
3239 -- This takes care of the boundary case, but it is preferable to
3240 -- use a smaller limit, because even on 64-bit architectures an
3241 -- array of more than 2 ** 30 bytes is likely to raise
3242 -- Storage_Error.
3246 then
3249 Condition =>
3251 Left_Opnd =>
3253 Left_Opnd =>
3255 Left_Opnd =>
3257 Prefix =>
3260 Right_Opnd =>
3262 Right_Opnd =>
3264 Left_Opnd =>
3266 Prefix =>
3269 Right_Opnd =>
3271 Right_Opnd =>
3277 ---------------------------------------
3278 -- Check_Pragma_Thread_Local_Storage --
3279 ---------------------------------------
3282 function Has_Incompatible_Initialization
3284 -- Determine whether variable Var_Id with declaration Var_Decl is
3285 -- initialized with a value that violates the semantics of pragma
3286 -- Thread_Local_Storage.
3288 -------------------------------------
3289 -- Has_Incompatible_Initialization --
3290 -------------------------------------
3292 function Has_Incompatible_Initialization
3294 is
3297 begin
3298 -- The variable is default-initialized. This directly violates
3299 -- the semantics of the pragma.
3304 -- The variable has explicit initialization. In this case only
3305 -- a handful of values satisfy the semantics of the pragma.
3309 then
3310 -- "null" is a legal form of initialization
3315 -- A static expression is a legal form of initialization
3320 -- A static aggregate is a legal form of initialization
3324 then
3327 -- All other initialization expressions violate the semantic
3328 -- of the pragma.
3330 else
3334 -- The variable lacks any kind of initialization, which agrees
3335 -- with the semantics of the pragma.
3337 else
3342 -- Local declarations
3346 -- Start of processing for Check_Pragma_Thread_Local_Storage
3348 begin
3349 -- A variable whose initialization is suppressed lacks any kind of
3350 -- initialization.
3355 -- The variable has default initialization, or is explicitly
3356 -- initialized to a value other than null, static expression,
3357 -- or a static aggregate.
3360 Error_Msg_NE
3363 Error_Msg_NE
3369 --------------------------------
3370 -- Has_Default_Initialization --
3371 --------------------------------
3373 function Has_Default_Initialization
3375 is
3379 begin
3380 return
3384 and then
3388 or else
3393 -- Local variables
3398 -- Start of processing for Freeze_Object_Declaration
3400 begin
3401 -- Abstract type allowed only for C++ imported variables or constants
3403 -- Note: we inhibit this check for objects that do not come from
3404 -- source because there is at least one case (the expansion of
3405 -- x'Class'Input where x is abstract) where we legitimately
3406 -- generate an abstract object.
3411 then
3420 Error_Msg_N -- CODEFIX
3425 -- For object created by object declaration, perform required
3426 -- categorization (preelaborate and pure) checks. Defer these
3427 -- checks to freeze time since pragma Import inhibits default
3428 -- initialization and thus pragma Import affects these checks.
3432 -- If there is an address clause, check that it is valid and if need
3433 -- be move initialization to the freeze node.
3437 -- Similar processing is needed for aspects that may affect object
3438 -- layout, like Alignment, if there is an initialization expression.
3439 -- We don't do this if there is a pragma Linker_Section, because it
3440 -- would prevent the back end from statically initializing the
3441 -- object; we don't want elaboration code in that case.
3444 and then Expander_Active
3448 then
3449 declare
3453 begin
3454 -- Capture initialization value at point of declaration, and
3455 -- make explicit assignment legal, because object may be a
3456 -- constant.
3461 -- Move initialization to freeze actions
3469 -- Set_Is_Frozen (E, False);
3473 -- Reset Is_True_Constant for non-constant aliased object. We
3474 -- consider that the fact that a non-constant object is aliased may
3475 -- indicate that some funny business is going on, e.g. an aliased
3476 -- object is passed by reference to a procedure which captures the
3477 -- address of the object, which is later used to assign a new value,
3478 -- even though the compiler thinks that it is not modified. Such
3479 -- code is highly dubious, but we choose to make it "work" for
3480 -- non-constant aliased objects.
3482 -- Note that we used to do this for all aliased objects, whether or
3483 -- not constant, but this caused anomalies down the line because we
3484 -- ended up with static objects that were not Is_True_Constant. Not
3485 -- resetting Is_True_Constant for (aliased) constant objects ensures
3486 -- that this anomaly never occurs.
3488 -- However, we don't do that for internal entities. We figure that if
3489 -- we deliberately set Is_True_Constant for an internal entity, e.g.
3490 -- a dispatch table entry, then we mean it.
3495 then
3499 -- If the object needs any kind of default initialization, an error
3500 -- must be issued if No_Default_Initialization applies. The check
3501 -- doesn't apply to imported objects, which are not ever default
3502 -- initialized, and is why the check is deferred until freezing, at
3503 -- which point we know if Import applies. Deferred constants are also
3504 -- exempted from this test because their completion is explicit, or
3505 -- through an import pragma.
3511 Check_Restriction
3515 -- Ensure that a variable subject to pragma Thread_Local_Storage
3516 --
3517 -- * Lacks default initialization, or
3518 --
3519 -- * The initialization expression is either "null", a static
3520 -- constant, or a compile-time known aggregate.
3526 -- For imported objects, set Is_Public unless there is also an
3527 -- address clause, which means that there is no external symbol
3528 -- needed for the Import (Is_Public may still be set for other
3529 -- unrelated reasons). Note that we delayed this processing
3530 -- till freeze time so that we can be sure not to set the flag
3531 -- if there is an address clause. If there is such a clause,
3532 -- then the only purpose of the Import pragma is to suppress
3533 -- implicit initialization.
3539 -- For source objects that are not Imported and are library level, if
3540 -- no linker section pragma was given inherit the appropriate linker
3541 -- section from the corresponding type.
3547 then
3551 -- For convention C objects of an enumeration type, warn if the size
3552 -- is not integer size and no explicit size given. Skip warning for
3553 -- Boolean and Character, and assume programmer expects 8-bit sizes
3554 -- for these cases.
3557 or else
3564 then
3566 Error_Msg_N
3576 -----------------------------
3577 -- Freeze_Generic_Entities --
3578 -----------------------------
3585 begin
3604 --------------------
3605 -- Freeze_Profile --
3606 --------------------
3613 begin
3614 -- Loop through formals
3620 -- AI05-0151: incomplete types can appear in a profile. By the
3621 -- time the entity is frozen, the full view must be available,
3622 -- unless it is a limited view.
3627 then
3641 then
3642 -- If the type of a formal is incomplete, subprogram is being
3643 -- frozen prematurely. Within an instance (but not within a
3644 -- wrapper package) this is an artifact of our need to regard
3645 -- the end of an instantiation as a freeze point. Otherwise it
3646 -- is a definite error.
3653 elsif not After_Last_Declaration
3654 and then not Freezing_Library_Level_Tagged_Type
3655 then
3657 Error_Msg
3662 -- Check suspicious parameter for C function. These tests apply
3663 -- only to exported/imported subprograms.
3665 if Warn_On_Export_Import
3668 or else
3675 then
3676 -- Qualify mention of formals with subprogram name
3680 -- Check suspicious use of fat C pointer, but do not emit
3681 -- a warning on an access to subprogram when unnesting is
3682 -- active.
3688 then
3689 Error_Msg_N
3692 -- Check suspicious return of boolean
3698 then
3699 Error_Msg_N
3701 Error_Msg_N
3705 -- Check suspicious tagged type
3708 or else
3712 then
3713 Error_Msg_N
3717 -- Check wrong convention subprogram pointer
3721 then
3722 Error_Msg_N
3726 Error_Msg_NE
3731 -- Turn off name qualification after message output
3736 -- Check for unconstrained array in exported foreign convention
3737 -- case.
3743 and then Warn_On_Export_Import
3744 then
3747 -- If this is an inherited operation, place the warning on
3748 -- the derived type declaration, rather than on the original
3749 -- subprogram.
3752 then
3758 else
3774 -- If the formal is an anonymous_access_to_subprogram
3775 -- freeze the subprogram type as well, to prevent
3776 -- scope anomalies in gigi, because there is no other
3777 -- clear point at which it could be frozen.
3781 then
3789 -- Case of function: similar checks on return type
3793 -- Freeze return type
3797 -- AI05-0151: the return type may have been incomplete at the
3798 -- point of declaration. Replace it with the full view, unless the
3799 -- current type is a limited view. In that case the full view is
3800 -- in a different unit, and gigi finds the non-limited view after
3801 -- the other unit is elaborated.
3806 then
3813 -- Check suspicious return type for C function
3815 if Warn_On_Export_Import
3817 or else
3820 then
3821 -- Check suspicious return of fat C pointer
3827 then
3828 Error_Msg_N
3830 E);
3832 -- Check suspicious return of boolean
3839 then
3840 declare
3843 begin
3844 Error_Msg_NE
3846 Error_Msg_NE
3851 -- Check suspicious return tagged type
3855 and then
3856 Is_Tagged_Type
3861 then
3865 -- Check return of wrong convention subprogram pointer
3871 then
3875 Error_Msg_NE
3881 -- Give warning for suspicious return of a result of an
3882 -- unconstrained array type in a foreign convention function.
3886 -- We are looking for a return of unconstrained array
3891 -- Exclude imported routines, the warning does not belong on
3892 -- the import, but rather on the routine definition.
3896 -- Check that general warning is enabled, and that it is not
3897 -- suppressed for this particular case.
3899 and then Warn_On_Export_Import
3902 then
3903 Error_Msg_N
3909 -- Check suspicious use of Import in pure unit (cases where the RM
3910 -- allows calls to be omitted).
3914 -- It might be suspicious if the compilation unit has the Pure
3915 -- aspect/pragma.
3919 -- The RM allows omission of calls only in the case of
3920 -- library-level subprograms (see RM-10.2.1(18)).
3924 -- Ignore internally generated entity. This happens in some cases
3925 -- of subprograms in specs, where we generate an implied body.
3929 -- Assume run-time knows what it is doing
3931 and then not GNAT_Mode
3933 -- Assume explicit Pure_Function means import is pure
3937 -- Don't need warning in relaxed semantics mode
3939 and then not Relaxed_RM_Semantics
3941 -- Assume convention Intrinsic is OK, since this is specialized.
3942 -- This deals with the DEC unit current_exception.ads
3946 -- Assume that ASM interface knows what it is doing. This deals
3947 -- with e.g. unsigned.ads in the AAMP back end.
3950 then
3951 Error_Msg_N
3953 Error_Msg_NE
3961 ------------------------
3962 -- Freeze_Record_Type --
3963 ------------------------
3975 -- Set True if we find at least one component which is aliased. This
3976 -- is used to prevent Implicit_Packing of the record, since packing
3977 -- cannot modify the size of alignment of an aliased component.
3980 -- True if all components are of a type whose underlying type is
3981 -- elementary.
3984 -- True if all components have a known RM_Size
3987 -- True if all components have an RM_Size that is a multiple of the
3988 -- storage unit.
3991 -- Accumulates total Esize values of all elementary components. Used
3992 -- for processing of Implicit_Packing.
3995 -- Set True if we find at least one component with a component
3996 -- clause (used to warn about useless Bit_Order pragmas, and also
3997 -- to detect cases where Implicit_Packing may have an effect).
4000 -- Set True if the record type scope Rec has been pushed on the scope
4001 -- stack. Needed for the analysis of delayed aspects specified to the
4002 -- components of Rec.
4005 -- Accumulates total RM_Size values of all sized components. Used
4006 -- for processing of Implicit_Packing.
4009 -- Accumulates total RM_Size values of all sized components, rounded
4010 -- individually to a multiple of the storage unit.
4013 -- Scalar_Storage_Order attribute definition clause for the record
4016 -- Set True if we find at least one component whose type has a
4017 -- Scalar_Storage_Order attribute definition clause.
4020 -- Set True if we find at least one component with no component
4021 -- clause (used to warn about useless Pack pragmas).
4024 -- If N is an allocator, possibly wrapped in one or more level of
4025 -- qualified expression(s), return the inner allocator node, else
4026 -- return Empty.
4029 -- If the component subtype is an access to a constrained subtype of
4030 -- an already frozen type, make the subtype frozen as well. It might
4031 -- otherwise be frozen in the wrong scope, and a freeze node on
4032 -- subtype has no effect. Similarly, if the component subtype is a
4033 -- regular (not protected) access to subprogram, set the anonymous
4034 -- subprogram type to frozen as well, to prevent an out-of-scope
4035 -- freeze node at some eventual point of call. Protected operations
4036 -- are handled elsewhere.
4039 -- Make sure that all types mentioned in Discrete_Choices of the
4040 -- variants referenceed by the Variant_Part VP are frozen. This is
4041 -- a recursive routine to deal with nested variants.
4043 ---------------------
4044 -- Check_Allocator --
4045 ---------------------
4049 begin
4051 loop
4056 else
4062 -----------------
4063 -- Check_Itype --
4064 -----------------
4069 begin
4072 then
4075 -- In addition, add an Itype_Reference to ensure that the
4076 -- access subtype is elaborated early enough. This cannot be
4077 -- done if the subtype may depend on discriminants.
4082 then
4090 then
4095 ------------------------------------
4096 -- Freeze_Choices_In_Variant_Part --
4097 ------------------------------------
4106 begin
4107 -- Loop through variants
4112 -- Loop through choices, checking that all types are frozen
4118 then
4125 -- Check for nested variant part to process
4139 -- Start of processing for Freeze_Record_Type
4141 begin
4142 -- Deal with delayed aspect specifications for components. The
4143 -- analysis of the aspect is required to be delayed to the freeze
4144 -- point, thus we analyze the pragma or attribute definition
4145 -- clause in the tree at this point. We also analyze the aspect
4146 -- specification node at the freeze point when the aspect doesn't
4147 -- correspond to pragma/attribute definition clause.
4153 then
4158 -- The visibility to the discriminants must be restored in
4159 -- order to properly analyze the aspects.
4172 -- Pop the scope if Rec scope has been pushed on the scope stack
4173 -- during the delayed aspect analysis process.
4180 Pop_Scope;
4183 -- Freeze components and embedded subtypes
4192 -- Handle the component and discriminant case
4195 declare
4198 begin
4199 -- Freezing a record type freezes the type of each of its
4200 -- components. However, if the type of the component is
4201 -- part of this record, we do not want or need a separate
4202 -- Freeze_Node. Note that Is_Itype is wrong because that's
4203 -- also set in private type cases. We also can't check for
4204 -- the Scope being exactly Rec because of private types and
4205 -- record extensions.
4210 then
4216 -- Warn for pragma Pack overriding foreign convention
4221 -- Don't warn for aliased components, since override
4222 -- cannot happen in that case.
4225 then
4226 declare
4231 begin
4235 Error_Msg_N
4237 PP);
4239 Error_Msg_NE
4246 -- Check for error of component clause given for variable
4247 -- sized type. We have to delay this test till this point,
4248 -- since the component type has to be frozen for us to know
4249 -- if it is variable length.
4254 -- We omit this test in a generic context, it will be
4255 -- applied at instantiation time.
4260 -- Also omit this test in CodePeer mode, since we do not
4261 -- have sufficient info on size and rep clauses.
4266 -- Omit check if component has a generic type. This can
4267 -- happen in an instantiation within a generic in ASIS
4268 -- mode, where we force freeze actions without full
4269 -- expansion.
4274 -- Do the check
4276 elsif not
4277 Size_Known_At_Compile_Time
4279 then
4280 Error_Msg_N
4285 else
4289 -- Case of component requires byte alignment
4293 -- Set the enclosing record to also require byte align
4297 -- Check for component clause that is inconsistent with
4298 -- the required byte boundary alignment.
4303 then
4304 Error_Msg_N
4312 -- Gather data for possible Implicit_Packing later. Note that at
4313 -- this stage we might be dealing with a real component, or with
4314 -- an implicit subtype declaration.
4317 declare
4322 begin
4323 Sized_Component_Total_RM_Size :=
4326 Sized_Component_Total_Round_RM_Size :=
4327 Sized_Component_Total_Round_RM_Size +
4332 then
4333 Elem_Component_Total_Esize :=
4335 else
4343 else
4347 -- If the component is an Itype with Delayed_Freeze and is either
4348 -- a record or array subtype and its base type has not yet been
4349 -- frozen, we must remove this from the entity list of this record
4350 -- and put it on the entity list of the scope of its base type.
4351 -- Note that we know that this is not the type of a component
4352 -- since we cleared Has_Delayed_Freeze for it in the previous
4353 -- loop. Thus this must be the Designated_Type of an access type,
4354 -- which is the type of a component.
4362 then
4363 declare
4367 begin
4368 -- We have a difficult case to handle here. Suppose Rec is
4369 -- subtype being defined in a subprogram that's created as
4370 -- part of the freezing of Rec'Base. In that case, we know
4371 -- that Comp'Base must have already been frozen by the time
4372 -- we get to elaborate this because Gigi doesn't elaborate
4373 -- any bodies until it has elaborated all of the declarative
4374 -- part. But Is_Frozen will not be set at this point because
4375 -- we are processing code in lexical order.
4377 -- We detect this case by going up the Scope chain of Rec
4378 -- and seeing if we have a subprogram scope before reaching
4379 -- the top of the scope chain or that of Comp'Base. If we
4380 -- do, then mark that Comp'Base will actually be frozen. If
4381 -- so, we merely undelay it.
4398 else
4401 else
4405 -- Insert in entity list of scope of base type (which
4406 -- must be an enclosing scope, because still unfrozen).
4412 -- If the component is an access type with an allocator as default
4413 -- value, the designated type will be frozen by the corresponding
4414 -- expression in init_proc. In order to place the freeze node for
4415 -- the designated type before that for the current record type,
4416 -- freeze it now.
4418 -- Same process if the component is an array of access types,
4419 -- initialized with an aggregate. If the designated type is
4420 -- private, it cannot contain allocators, and it is premature
4421 -- to freeze the type, so we check for this as well.
4426 then
4427 declare
4431 begin
4434 -- If component is pointer to a class-wide type, freeze
4435 -- the specific type in the expression being allocated.
4436 -- The expression may be a subtype indication, in which
4437 -- case freeze the subtype mark.
4439 if Is_Class_Wide_Type
4441 then
4443 Freeze_And_Append
4447 then
4448 Freeze_And_Append
4456 else
4457 Freeze_And_Append
4465 then
4468 -- Freeze the designated type when initializing a component with
4469 -- an aggregate in case the aggregate contains allocators.
4471 -- type T is ...;
4472 -- type T_Ptr is access all T;
4473 -- type T_Array is array ... of T_Ptr;
4475 -- type Rec is record
4476 -- Comp : T_Array := (others => ...);
4477 -- end record;
4481 then
4482 declare
4485 Designated_Type
4488 begin
4489 -- The only case when this sort of freezing is not done is
4490 -- when the designated type is class-wide and the root type
4491 -- is the record owning the component. This scenario results
4492 -- in a circularity because the class-wide type requires
4493 -- primitives that have not been created yet as the root
4494 -- type is in the process of being frozen.
4496 -- type Rec is tagged;
4497 -- type Rec_Ptr is access all Rec'Class;
4498 -- type Rec_Array is array ... of Rec_Ptr;
4500 -- type Rec is record
4501 -- Comp : Rec_Array := (others => ...);
4502 -- end record;
4506 then
4514 then
4524 SSO_ADC :=
4525 Get_Attribute_Definition_Clause
4528 -- If the record type has Complex_Representation, then it is treated
4529 -- as a scalar in the back end so the storage order is irrelevant.
4533 Error_Msg_N
4535 SSO_ADC);
4538 else
4539 -- Deal with default setting of reverse storage order
4543 -- Check consistent attribute setting on component types
4545 declare
4547 begin
4550 Check_Component_Storage_Order
4560 -- Now deal with reverse storage order/bit order issues
4564 -- Check compatibility of Scalar_Storage_Order with Bit_Order,
4565 -- if the former is specified.
4569 -- Note: report error on Rec, not on SSO_ADC, as ADC may
4570 -- apply to some ancestor type.
4573 Error_Msg_N
4578 -- Warn if there is a Scalar_Storage_Order attribute definition
4579 -- clause but no component clause, no component that itself has
4580 -- such an attribute definition, and no pragma Pack.
4583 or else
4584 SSO_ADC_Component
4585 or else
4587 then
4588 Error_Msg_N
4595 -- Deal with Bit_Order aspect
4603 then
4604 -- Warn if clause has no effect when no component clause is
4605 -- present, but suppress warning if the Bit_Order is required
4606 -- due to the presence of a Scalar_Storage_Order attribute.
4608 Error_Msg_N
4610 Error_Msg_N
4613 -- Here is where we do the processing to adjust component clauses
4614 -- for reversed bit order, when not using reverse SSO. If an error
4615 -- has been reported on Rec already (such as SSO incompatible with
4616 -- bit order), don't bother adjusting as this may generate extra
4617 -- noise.
4622 then
4625 -- Case where we have both an explicit Bit_Order and the same
4626 -- Scalar_Storage_Order: leave record untouched, the back-end
4627 -- will take care of required layout conversions.
4629 else
4635 -- Complete error checking on record representation clause (e.g.
4636 -- overlap of components). This is called after adjusting the
4637 -- record for reverse bit order.
4639 declare
4641 begin
4647 -- Check for useless pragma Pack when all components placed. We only
4648 -- do this check for record types, not subtypes, since a subtype may
4649 -- have all its components placed, and it still makes perfectly good
4650 -- sense to pack other subtypes or the parent type. We do not give
4651 -- this warning if Optimize_Alignment is set to Space, since the
4652 -- pragma Pack does have an effect in this case (it always resets
4653 -- the alignment to one).
4657 and then not Unplaced_Component
4659 then
4660 -- Reset packed status. Probably not necessary, but we do it so
4661 -- that there is no chance of the back end doing something strange
4662 -- with this redundant indication of packing.
4666 -- Give warning if redundant constructs warnings on
4669 Error_Msg_N -- CODEFIX
4675 -- If this is the record corresponding to a remote type, freeze the
4676 -- remote type here since that is what we are semantically freezing.
4677 -- This prevents the freeze node for that type in an inner scope.
4684 -- Check for controlled components, unchecked unions, and type
4685 -- invariants.
4690 -- Do not set Has_Controlled_Component on a class-wide
4691 -- equivalent type. See Make_CW_Equivalent_Type.
4694 and then
4696 or else
4699 or else
4701 and then
4703 and then
4704 Has_Controlled_Component
4706 then
4714 -- The record type requires its own invariant procedure in
4715 -- order to verify the invariant of each individual component.
4716 -- Do not consider internal components such as _parent because
4717 -- parent class-wide invariants are always inherited.
4718 -- In GNATprove mode, the component invariants are checked by
4719 -- other means. They should not be added to the record type
4720 -- invariant procedure, so that the procedure can be used to
4721 -- check the recordy type invariants if any.
4725 and then not GNATprove_Mode
4726 then
4730 -- Scan component declaration for likely misuses of current
4731 -- instance, either in a constraint or a default expression.
4741 -- Enforce the restriction that access attributes with a current
4742 -- instance prefix can only apply to limited types. This comment
4743 -- is floating here, but does not seem to belong here???
4745 -- Set component alignment if not otherwise already set
4749 -- For first subtypes, check if there are any fixed-point fields with
4750 -- component clauses, where we must check the size. This is not done
4751 -- till the freeze point since for fixed-point types, we do not know
4752 -- the size until the type is frozen. Similar processing applies to
4753 -- bit-packed arrays.
4761 then
4762 Check_Size
4766 Junk);
4773 -- See if Size is too small as is (and implicit packing might help)
4777 -- No implicit packing if even one component is explicitly placed
4779 and then not Placed_Component
4781 -- Or even one component is aliased
4783 and then not Aliased_Component
4785 -- Must have size clause and all sized components
4788 and then All_Sized_Components
4790 -- Do not try implicit packing on records with discriminants, too
4791 -- complicated, especially in the variant record case.
4795 -- We want to implicitly pack if the specified size of the record
4796 -- is less than the sum of the object sizes (no point in packing
4797 -- if this is not the case), if we can compute it, i.e. if we have
4798 -- only elementary components. Otherwise, we have at least one
4799 -- composite component and we want to implicitly pack only if bit
4800 -- packing is required for it, as we are sure in this case that
4801 -- the back end cannot do the expected layout without packing.
4803 and then
4804 ((All_Elem_Components
4806 or else
4808 and then not All_Storage_Unit_Components
4811 -- And the total RM size cannot be greater than the specified size
4812 -- since otherwise packing will not get us where we have to be.
4816 -- Never do implicit packing in CodePeer or SPARK modes since
4817 -- we don't do any packing in these modes, since this generates
4818 -- over-complex code that confuses static analysis, and in
4819 -- general, neither CodePeer not GNATprove care about the
4820 -- internal representation of objects.
4823 then
4824 -- If implicit packing enabled, do it
4829 -- Otherwise flag the size clause
4831 else
4832 declare
4834 begin
4835 Error_Msg_NE -- CODEFIX
4837 Error_Msg_N -- CODEFIX
4844 -- The following checks are relevant only when SPARK_Mode is on as
4845 -- they are not standard Ada legality rules.
4849 -- A discriminated type cannot be effectively volatile
4850 -- (SPARK RM 7.1.3(5)).
4857 -- A non-effectively volatile record type cannot contain
4858 -- effectively volatile components (SPARK RM 7.1.3(6)).
4860 else
4865 then
4867 Error_Msg_N
4876 -- A type which does not yield a synchronized object cannot have
4877 -- a component that yields a synchronized object (SPARK RM 9.5).
4884 then
4886 Error_Msg_N
4895 -- A Ghost type cannot have a component of protected or task type
4896 -- (SPARK RM 6.9(19)).
4903 then
4905 Error_Msg_N
4907 Comp);
4915 -- Make sure that if we have an iterator aspect, then we have
4916 -- either Constant_Indexing or Variable_Indexing.
4918 declare
4921 begin
4930 or else
4932 then
4934 else
4935 Error_Msg_N
4937 Iterator_Aspect);
4942 -- All done if not a full record definition
4948 -- Finally we need to check the variant part to make sure that
4949 -- all types within choices are properly frozen as part of the
4950 -- freezing of the record type.
4957 begin
4958 -- Find component list
4970 then
4975 -- Case of variant part present
4981 -- Note: we used to call Check_Choices here, but it is too early,
4982 -- since predicated subtypes are frozen here, but their freezing
4983 -- actions are in Analyze_Freeze_Entity, which has not been called
4984 -- yet for entities frozen within this procedure, so we moved that
4985 -- call to the Analyze_Freeze_Entity for the record type.
4989 -- Check that all the primitives of an interface type are abstract
4990 -- or null procedures.
4994 then
4995 declare
4999 begin
5006 -- Avoid reporting the error on inherited primitives
5009 then
5014 Error_Msg_N
5018 else
5019 Error_Msg_N
5030 -- For a derived tagged type, check whether inherited primitives
5031 -- might require a wrapper to handle class-wide conditions.
5038 -------------------------------
5039 -- Has_Boolean_Aspect_Import --
5040 -------------------------------
5047 begin
5053 -- The value of aspect Import is True when the expression is
5054 -- either missing or it is explicitly set to True.
5060 then
5071 -------------------------
5072 -- Inherit_Freeze_Node --
5073 -------------------------
5075 procedure Inherit_Freeze_Node
5078 is
5081 begin
5085 -- The input type had an existing node. Propagate relevant attributes
5086 -- from the old freeze node to the inherited freeze node.
5088 -- ??? if both freeze nodes have attributes, would they differ?
5092 -- Attribute Access_Types_To_Process
5096 then
5101 -- Attribute Actions
5107 -- Attribute First_Subtype_Link
5111 then
5115 -- Attribute TSS_Elist
5119 then
5125 ------------------------------
5126 -- Wrap_Imported_Subprogram --
5127 ------------------------------
5129 -- The issue here is that our normal approach of checking preconditions
5130 -- and postconditions does not work for imported procedures, since we
5131 -- are not generating code for the body. To get around this we create
5132 -- a wrapper, as shown by the following example:
5134 -- procedure K (A : Integer);
5135 -- pragma Import (C, K);
5137 -- The spec is rewritten by removing the effects of pragma Import, but
5138 -- leaving the convention unchanged, as though the source had said:
5140 -- procedure K (A : Integer);
5141 -- pragma Convention (C, K);
5143 -- and we create a body, added to the entity K freeze actions, which
5144 -- looks like:
5146 -- procedure K (A : Integer) is
5147 -- procedure K (A : Integer);
5148 -- pragma Import (C, K);
5149 -- begin
5150 -- K (A);
5151 -- end K;
5153 -- Now the contract applies in the normal way to the outer procedure,
5154 -- and the inner procedure has no contracts, so there is no problem
5155 -- in just calling it to get the original effect.
5157 -- In the case of a function, we create an appropriate return statement
5158 -- for the subprogram body that calls the inner procedure.
5162 -- Obtain a copy of the Import_Pragma which belongs to subprogram E
5164 ------------------------
5165 -- Copy_Import_Pragma --
5166 ------------------------
5170 -- The subprogram should have an import pragma, otherwise it does
5171 -- need a wrapper.
5176 -- Save all semantic fields of the pragma
5185 begin
5186 -- Reset all semantic fields. This avoids a potential infinite
5187 -- loop when the pragma comes from an aspect as the duplication
5188 -- will copy the aspect, then copy the corresponding pragma and
5189 -- so on.
5198 -- Restore the original semantic fields
5208 -- Local variables
5219 -- Start of processing for Wrap_Imported_Subprogram
5221 begin
5222 -- Nothing to do if not imported
5227 -- Test enabling conditions for wrapping
5232 and then not GNATprove_Mode
5233 then
5234 -- Here we do the wrap
5236 -- Note on calls to Copy_Separate_Tree. The trees we are copying
5237 -- here are fully analyzed, but we definitely want fully syntactic
5238 -- unanalyzed trees in the body we construct, so that the analysis
5239 -- generates the right visibility, and that is exactly what the
5240 -- calls to Copy_Separate_Tree give us.
5244 -- Fix up spec so it is no longer imported and has convention Ada
5252 -- Grab the subprogram declaration and specification
5256 -- Build parameter list that we need
5265 -- Build the call
5267 -- An imported function whose result type is anonymous access
5268 -- creates a new anonymous access type when it is relocated into
5269 -- the declarations of the body generated below. As a result, the
5270 -- accessibility level of these two anonymous access types may not
5271 -- be compatible even though they are essentially the same type.
5272 -- Use an unchecked type conversion to reconcile this case. Note
5273 -- that the conversion is safe because in the named access type
5274 -- case, both the body and imported function utilize the same
5275 -- type.
5278 Stmt :=
5280 Expression =>
5286 else
5287 Stmt :=
5293 -- Now build the body
5295 Bod :=
5297 Specification =>
5302 Prag),
5303 Handled_Statement_Sequence =>
5308 -- Append the body to freeze result
5313 -- Case of imported subprogram that does not get wrapped
5315 else
5316 -- Set Is_Public. All imported entities need an external symbol
5317 -- created for them since they are always referenced from another
5318 -- object file. Note this used to be set when we set Is_Imported
5319 -- back in Sem_Prag, but now we delay it to this point, since we
5320 -- don't want to set this flag if we wrap an imported subprogram.
5326 -- Start of processing for Freeze_Entity
5328 begin
5329 -- The entity being frozen may be subject to pragma Ghost. Set the mode
5330 -- now to ensure that any nodes generated during freezing are properly
5331 -- flagged as Ghost.
5335 -- We are going to test for various reasons why this entity need not be
5336 -- frozen here, but in the case of an Itype that's defined within a
5337 -- record, that test actually applies to the record.
5344 then
5348 -- Do not freeze if already frozen since we only need one freeze node
5354 -- Do not freeze if we are preanalyzing without freezing
5364 -- It is improper to freeze an external entity within a generic because
5365 -- its freeze node will appear in a non-valid context. The entity will
5366 -- be frozen in the proper scope after the current generic is analyzed.
5367 -- However, aspects must be analyzed because they may be queried later
5368 -- within the generic itself, and the corresponding pragma or attribute
5369 -- definition has not been analyzed yet. After this, indicate that the
5370 -- entity has no further delayed aspects, to prevent a later aspect
5371 -- analysis out of the scope of the generic.
5382 -- AI05-0213: A formal incomplete type does not freeze the actual. In
5383 -- the instance, the same applies to the subtype renaming the actual.
5389 then
5393 -- Formal subprograms are never frozen
5399 -- Generic types are never frozen as they lack delayed semantic checks
5405 -- Do not freeze a global entity within an inner scope created during
5406 -- expansion. A call to subprogram E within some internal procedure
5407 -- (a stream attribute for example) might require freezing E, but the
5408 -- freeze node must appear in the same declarative part as E itself.
5409 -- The two-pass elaboration mechanism in gigi guarantees that E will
5410 -- be frozen before the inner call is elaborated. We exclude constants
5411 -- from this test, because deferred constants may be frozen early, and
5412 -- must be diagnosed (e.g. in the case of a deferred constant being used
5413 -- in a default expression). If the enclosing subprogram comes from
5414 -- source, or is a generic instance, then the freeze point is the one
5415 -- mandated by the language, and we freeze the entity. A subprogram that
5416 -- is a child unit body that acts as a spec does not have a spec that
5417 -- comes from source, but can only come from source.
5422 then
5423 declare
5426 begin
5433 then
5435 else
5445 -- Similarly, an inlined instance body may make reference to global
5446 -- entities, but these references cannot be the proper freezing point
5447 -- for them, and in the absence of inlining freezing will take place in
5448 -- their own scope. Normally instance bodies are analyzed after the
5449 -- enclosing compilation, and everything has been frozen at the proper
5450 -- place, but with front-end inlining an instance body is compiled
5451 -- before the end of the enclosing scope, and as a result out-of-order
5452 -- freezing must be prevented.
5454 elsif Front_End_Inlining
5455 and then In_Instance_Body
5457 then
5458 declare
5461 begin
5466 else
5478 -- Add checks to detect proper initialization of scalars that may appear
5479 -- as subprogram parameters.
5485 -- Deal with delayed aspect specifications. The analysis of the aspect
5486 -- is required to be delayed to the freeze point, thus we analyze the
5487 -- pragma or attribute definition clause in the tree at this point. We
5488 -- also analyze the aspect specification node at the freeze point when
5489 -- the aspect doesn't correspond to pragma/attribute definition clause.
5490 -- In addition, a derived type may have inherited aspects that were
5491 -- delayed in the parent, so these must also be captured now.
5495 then
5499 -- Here to freeze the entity
5503 -- Case of entity being frozen is other than a type
5507 -- If entity is exported or imported and does not have an external
5508 -- name, now is the time to provide the appropriate default name.
5509 -- Skip this if the entity is stubbed, since we don't need a name
5510 -- for any stubbed routine. For the case on intrinsics, if no
5511 -- external name is specified, then calls will be handled in
5512 -- Exp_Intr.Expand_Intrinsic_Call, and no name is needed. If an
5513 -- external name is provided, then Expand_Intrinsic_Call leaves
5514 -- calls in place for expansion by GIGI.
5520 then
5521 Set_Encoded_Interface_Name
5524 -- If entity is an atomic object appearing in a declaration and
5525 -- the expression is an aggregate, assign it to a temporary to
5526 -- ensure that the actual assignment is done atomically rather
5527 -- than component-wise (the assignment to the temp may be done
5528 -- component-wise, but that is harmless).
5535 then
5539 -- Subprogram case
5543 -- Check for needing to wrap imported subprogram
5547 -- Freeze all parameter types and the return type (RM 13.14(14)).
5548 -- However skip this for internal subprograms. This is also where
5549 -- any extra formal parameters are created since we now know
5550 -- whether the subprogram will use a foreign convention.
5552 -- In Ada 2012, freezing a subprogram does not always freeze the
5553 -- corresponding profile (see AI05-019). An attribute reference
5554 -- is not a freezing point of the profile. Flag Do_Freeze_Profile
5555 -- indicates whether the profile should be frozen now.
5556 -- Other constructs that should not freeze ???
5558 -- This processing doesn't apply to internal entities (see below)
5566 -- Must freeze its parent first if it is a derived subprogram
5572 -- We don't freeze internal subprograms, because we don't normally
5573 -- want addition of extra formals or mechanism setting to happen
5574 -- for those. However we do pass through predefined dispatching
5575 -- cases, since extra formals may be needed in some cases, such as
5576 -- for the stream 'Input function (build-in-place formals).
5580 then
5584 -- If warning on suspicious contracts then check for the case of
5585 -- a postcondition other than False for a No_Return subprogram.
5588 and then Warn_On_Suspicious_Contract
5590 then
5591 declare
5595 begin
5598 Name_Post,
5599 Name_Postcondition,
5600 Name_Refined_Post)
5601 then
5602 Exp :=
5603 Expression
5608 then
5609 Error_Msg_NE
5620 -- Here for other than a subprogram or type
5622 else
5623 -- If entity has a type, and it is not a generic unit, then freeze
5624 -- it first (RM 13.14(10)).
5628 then
5631 -- For an object of an anonymous array type, aspects on the
5632 -- object declaration apply to the type itself. This is the
5633 -- case for Atomic_Components, Volatile_Components, and
5634 -- Independent_Components. In these cases analysis of the
5635 -- generated pragma will mark the anonymous types accordingly,
5636 -- and the object itself does not require a freeze node.
5642 then
5649 -- Special processing for objects created by object declaration
5655 -- Check that a constant which has a pragma Volatile[_Components]
5656 -- or Atomic[_Components] also has a pragma Import (RM C.6(13)).
5658 -- Note: Atomic[_Components] also sets Volatile[_Components]
5664 then
5665 -- Make sure we actually have a pragma, and have not merely
5666 -- inherited the indication from elsewhere (e.g. an address
5667 -- clause, which is not good enough in RM terms).
5670 or else
5672 then
5673 Error_Msg_N
5678 or else
5680 then
5681 Error_Msg_N
5687 -- Static objects require special handling
5691 then
5695 -- Remaining step is to layout objects
5699 then
5703 -- For an object that does not have delayed freezing, and whose
5704 -- initialization actions have been captured in a compound
5705 -- statement, move them back now directly within the enclosing
5706 -- statement sequence.
5710 then
5714 -- Do not generate a freeze node for a generic unit
5722 -- Case of a type or subtype being frozen
5724 else
5725 -- Verify several SPARK legality rules related to Ghost types now
5726 -- that the type is frozen.
5730 -- We used to check here that a full type must have preelaborable
5731 -- initialization if it completes a private type specified with
5732 -- pragma Preelaborable_Initialization, but that missed cases where
5733 -- the types occur within a generic package, since the freezing
5734 -- that occurs within a containing scope generally skips traversal
5735 -- of a generic unit's declarations (those will be frozen within
5736 -- instances). This check was moved to Analyze_Package_Specification.
5738 -- The type may be defined in a generic unit. This can occur when
5739 -- freezing a generic function that returns the type (which is
5740 -- defined in a parent unit). It is clearly meaningless to freeze
5741 -- this type. However, if it is a subtype, its size may be determi-
5742 -- nable and used in subsequent checks, so might as well try to
5743 -- compute it.
5745 -- In Ada 2012, Freeze_Entities is also used in the front end to
5746 -- trigger the analysis of aspect expressions, so in this case we
5747 -- want to continue the freezing process.
5749 -- Is_Generic_Unit (Scope (E)) is dubious here, do we want instead
5750 -- In_Generic_Scope (E)???
5754 and then
5757 then
5763 -- Check for error of Type_Invariant'Class applied to an untagged
5764 -- type (check delayed to freeze time when full type is available).
5766 declare
5768 begin
5772 then
5773 Error_Msg_NE
5775 Error_Msg_N
5780 -- Deal with special cases of freezing for subtype
5784 -- Before we do anything else, a specific test for the case of a
5785 -- size given for an array where the array would need to be packed
5786 -- in order for the size to be honored, but is not. This is the
5787 -- case where implicit packing may apply. The reason we do this so
5788 -- early is that, if we have implicit packing, the layout of the
5789 -- base type is affected, so we must do this before we freeze the
5790 -- base type.
5792 -- We could do this processing only if implicit packing is enabled
5793 -- since in all other cases, the error would be caught by the back
5794 -- end. However, we choose to do the check even if we do not have
5795 -- implicit packing enabled, since this allows us to give a more
5796 -- useful error message (advising use of pragma Implicit_Packing
5797 -- or pragma Pack).
5800 declare
5812 -- Number of elements in array
5814 begin
5815 -- Check enabling conditions. These are straightforward
5816 -- except for the test for a limited composite type. This
5817 -- eliminates the rare case of a array of limited components
5818 -- where there are issues of whether or not we can go ahead
5819 -- and pack the array (since we can't freely pack and unpack
5820 -- arrays if they are limited).
5822 -- Note that we check the root type explicitly because the
5823 -- whole point is we are doing this test before we have had
5824 -- a chance to freeze the base type (and it is that freeze
5825 -- action that causes stuff to be inherited).
5827 -- The conditions on the size are identical to those used in
5828 -- Freeze_Array_Type to set the Is_Packed flag.
5846 then
5847 -- Compute number of elements in array
5854 and then
5856 then
5864 else
5871 -- What we are looking for here is the situation where
5872 -- the RM_Size given would be exactly right if there was
5873 -- a pragma Pack, resulting in the component size being
5874 -- the RM_Size of the component type.
5878 -- For implicit packing mode, just set the component
5879 -- size and Freeze_Array_Type will do the rest.
5884 -- Otherwise give an error message
5886 else
5887 Error_Msg_NE
5889 Error_Msg_N -- CODEFIX
5900 -- If ancestor subtype present, freeze that first. Note that this
5901 -- will also get the base type frozen. Need RM reference ???
5908 -- No ancestor subtype present
5910 else
5911 -- See if we have a nearest ancestor that has a predicate.
5912 -- That catches the case of derived type with a predicate.
5913 -- Need RM reference here ???
5921 -- Freeze base type before freezing the entity (RM 13.14(15))
5928 -- A subtype inherits all the type-related representation aspects
5929 -- from its parents (RM 13.1(8)).
5933 -- For a derived type, freeze its parent type first (RM 13.14(15))
5939 -- A derived type inherits each type-related representation aspect
5940 -- of its parent type that was directly specified before the
5941 -- declaration of the derived type (RM 13.1(15)).
5946 -- Check for incompatible size and alignment for record type
5948 if Warn_On_Size_Alignment
5952 -- If explicit Object_Size clause given assume that the programmer
5953 -- knows what he is doing, and expects the compiler behavior.
5957 -- Check for size not a multiple of alignment
5960 then
5961 declare
5967 begin
5970 -- Give a warning
5974 Error_Msg_NE
5981 else
5983 Error_Msg_NE
5997 -- Array type
6002 -- For a class-wide type, the corresponding specific type is
6003 -- frozen as well (RM 13.14(15))
6008 -- If the base type of the class-wide type is still incomplete,
6009 -- the class-wide remains unfrozen as well. This is legal when
6010 -- E is the formal of a primitive operation of some other type
6011 -- which is being frozen.
6018 -- The equivalent type associated with a class-wide subtype needs
6019 -- to be frozen to ensure that its layout is done.
6023 then
6027 -- Generate an itype reference for a library-level class-wide type
6028 -- at the freeze point. Otherwise the first explicit reference to
6029 -- the type may appear in an inner scope which will be rejected by
6030 -- the back-end.
6034 then
6035 declare
6038 begin
6041 -- From a gigi point of view, a class-wide subtype derives
6042 -- from its record equivalent type. As a result, the itype
6043 -- reference must appear after the freeze node of the
6044 -- equivalent type or gigi will reject the reference.
6048 then
6050 else
6056 -- For a record type or record subtype, freeze all component types
6057 -- (RM 13.14(15)). We test for E_Record_(sub)Type here, rather than
6058 -- using Is_Record_Type, because we don't want to attempt the freeze
6059 -- for the case of a private type with record extension (we will do
6060 -- that later when the full type is frozen).
6067 -- Report a warning if a discriminated record base type has a
6068 -- convention with language C or C++ applied to it. This check is
6069 -- done even within generic scopes (but not in instantiations),
6070 -- which is why we don't do it as part of Freeze_Record_Type.
6074 -- For a concurrent type, freeze corresponding record type. This does
6075 -- not correspond to any specific rule in the RM, but the record type
6076 -- is essentially part of the concurrent type. Also freeze all local
6077 -- entities. This includes record types created for entry parameter
6078 -- blocks and whatever local entities may appear in the private part.
6092 -- The guard on the presence of the Etype seems to be needed
6093 -- for some CodePeer (-gnatcC) cases, but not clear why???
6098 then
6109 -- Private types are required to point to the same freeze node as
6110 -- their corresponding full views. The freeze node itself has to
6111 -- point to the partial view of the entity (because from the partial
6112 -- view, we can retrieve the full view, but not the reverse).
6113 -- However, in order to freeze correctly, we need to freeze the full
6114 -- view. If we are freezing at the end of a scope (or within the
6115 -- scope) of the private type, the partial and full views will have
6116 -- been swapped, the full view appears first in the entity chain and
6117 -- the swapping mechanism ensures that the pointers are properly set
6118 -- (on scope exit).
6120 -- If we encounter the partial view before the full view (e.g. when
6121 -- freezing from another scope), we freeze the full view, and then
6122 -- set the pointers appropriately since we cannot rely on swapping to
6123 -- fix things up (subtypes in an outer scope might not get swapped).
6125 -- If the full view is itself private, the above requirements apply
6126 -- to the underlying full view instead of the full view. But there is
6127 -- no swapping mechanism for the underlying full view so we need to
6128 -- set the pointers appropriately in both cases.
6132 then
6133 -- The construction of the dispatch table associated with library
6134 -- level tagged types forces freezing of all the primitives of the
6135 -- type, which may cause premature freezing of the partial view.
6136 -- For example:
6138 -- package Pkg is
6139 -- type T is tagged private;
6140 -- type DT is new T with private;
6141 -- procedure Prim (X : in out T; Y : in out DT'Class);
6142 -- private
6143 -- type T is tagged null record;
6144 -- Obj : T;
6145 -- type DT is new T with null record;
6146 -- end;
6148 -- In this case the type will be frozen later by the usual
6149 -- mechanism: an object declaration, an instantiation, or the
6150 -- end of a declarative part.
6154 then
6158 -- Case of full view present
6162 -- If full view has already been frozen, then no further
6163 -- processing is required
6169 -- Otherwise freeze full view and patch the pointers so that
6170 -- the freeze node will elaborate both views in the back end.
6171 -- However, if full view is itself private, freeze underlying
6172 -- full view instead and patch the pointers so that the freeze
6173 -- node will elaborate the three views in the back end.
6175 else
6176 declare
6179 begin
6182 then
6190 then
6194 Inherit_Freeze_Node
6197 else
6207 Inherit_Freeze_Node
6210 else
6211 -- {Incomplete,Private}_Subtypes with Full_Views
6212 -- constrained by discriminants.
6223 -- AI-117 requires that the convention of a partial view be the
6224 -- same as the convention of the full view. Note that this is a
6225 -- recognized breach of privacy, but it's essential for logical
6226 -- consistency of representation, and the lack of a rule in
6227 -- RM95 was an oversight.
6234 -- Size information is copied from the full view to the
6235 -- incomplete or private view for consistency.
6237 -- We skip this is the full view is not a type. This is very
6238 -- strange of course, and can only happen as a result of
6239 -- certain illegalities, such as a premature attempt to derive
6240 -- from an incomplete type.
6249 -- Case of underlying full view present
6253 then
6258 -- Patch the pointers so that the freeze node will elaborate
6259 -- both views in the back end.
6265 Inherit_Freeze_Node
6268 else
6278 -- Case of no full view present. If entity is subtype or derived,
6279 -- it is safe to freeze, correctness depends on the frozen status
6280 -- of parent. Otherwise it is either premature usage, or a Taft
6281 -- amendment type, so diagnosis is at the point of use and the
6282 -- type might be frozen later.
6285 declare
6288 begin
6289 -- However, if the base type is itself private and has no
6290 -- (underlying) full view either, wait until the full type
6291 -- declaration is seen and all the full views are created.
6298 then
6308 else
6314 -- For access subprogram, freeze types of all formals, the return
6315 -- type was already frozen, since it is the Etype of the function.
6316 -- Formal types can be tagged Taft amendment types, but otherwise
6317 -- they cannot be incomplete.
6324 then
6328 -- AI05-151: Incomplete types are allowed in access to
6329 -- subprogram specifications.
6332 Error_Msg_NE
6343 -- For access to a protected subprogram, freeze the equivalent type
6344 -- (however this is not set if we are not generating code or if this
6345 -- is an anonymous type used just for resolution).
6353 -- Generic types are never seen by the back-end, and are also not
6354 -- processed by the expander (since the expander is turned off for
6355 -- generic processing), so we never need freeze nodes for them.
6361 -- Some special processing for non-generic types to complete
6362 -- representation details not known till the freeze point.
6367 -- Some error checks required for ordinary fixed-point type. Defer
6368 -- these till the freeze-point since we need the small and range
6369 -- values. We only do these checks for base types
6374 Error_Msg_N
6379 Error_Msg_N
6385 Error_Msg_N
6391 Error_Msg_N
6403 and then Warn_On_Suspicious_Modulus_Value
6404 then
6408 -- The pool applies to named and anonymous access types, but not
6409 -- to subprogram and to internal types generated for 'Access
6410 -- references.
6415 then
6416 -- If a pragma Default_Storage_Pool applies, and this type has no
6417 -- Storage_Pool or Storage_Size clause (which must have occurred
6418 -- before the freezing point), then use the default. This applies
6419 -- only to base types.
6421 -- None of this applies to access to subprograms, for which there
6422 -- are clearly no pools.
6428 then
6429 -- Case of pragma Default_Storage_Pool (null)
6434 -- Case of pragma Default_Storage_Pool (storage_pool_NAME)
6436 else
6441 -- Check restriction for standard storage pool
6447 -- Deal with error message for pure access type. This is not an
6448 -- error in Ada 2005 if there is no pool (see AI-366).
6454 then
6458 Error_Msg_N
6462 Error_Msg_N
6465 else
6466 Error_Msg_N
6473 -- Case of composite types
6477 -- AI-117 requires that all new primitives of a tagged type must
6478 -- inherit the convention of the full view of the type. Inherited
6479 -- and overriding operations are defined to inherit the convention
6480 -- of their parent or overridden subprogram (also specified in
6481 -- AI-117), which will have occurred earlier (in Derive_Subprogram
6482 -- and New_Overloaded_Entity). Here we set the convention of
6483 -- primitives that are still convention Ada, which will ensure
6484 -- that any new primitives inherit the type's convention. Class-
6485 -- wide types can have a foreign convention inherited from their
6486 -- specific type, but are excluded from this since they don't have
6487 -- any associated primitives.
6492 then
6493 declare
6497 begin
6509 -- If the type is a simple storage pool type, then this is where
6510 -- we attempt to locate and validate its Allocate, Deallocate, and
6511 -- Storage_Size operations (the first is required, and the latter
6512 -- two are optional). We also verify that the full type for a
6513 -- private type is allowed to be a simple storage pool type.
6517 then
6518 -- If the type is marked Has_Private_Declaration, then this is
6519 -- a full type for a private type that was specified with the
6520 -- pragma Simple_Storage_Pool_Type, and here we ensure that the
6521 -- pragma is allowed for the full type (for example, it can't
6522 -- be an array type, or a nonlimited record type).
6527 then
6529 Error_Msg_N
6540 procedure Validate_Simple_Pool_Op_Formal
6547 -- Validate one formal Pool_Op_Formal of the candidate pool
6548 -- operation Pool_Op. The formal must be of Expected_Type
6549 -- and have mode Expected_Mode. OK_Formal will be set to
6550 -- False if the formal doesn't match. If OK_Formal is False
6551 -- on entry, then the formal will effectively be ignored
6552 -- (because validation of the pool op has already failed).
6553 -- Upon return, Pool_Op_Formal will be updated to the next
6554 -- formal, if any.
6556 procedure Validate_Simple_Pool_Operation
6558 -- Search for and validate a simple pool operation with the
6559 -- name Op_Name. If the name is Allocate, then there must be
6560 -- exactly one such primitive operation for the simple pool
6561 -- type. If the name is Deallocate or Storage_Size, then
6562 -- there can be at most one such primitive operation. The
6563 -- profile of the located primitive must conform to what
6564 -- is expected for each operation.
6566 ------------------------------------
6567 -- Validate_Simple_Pool_Op_Formal --
6568 ------------------------------------
6570 procedure Validate_Simple_Pool_Op_Formal
6577 is
6578 begin
6579 -- If OK_Formal is False on entry, then simply ignore
6580 -- the formal, because an earlier formal has already
6581 -- been flagged.
6586 -- If no formal is passed in, then issue an error for a
6587 -- missing formal.
6590 Error_Msg_NE
6600 -- If the pool type was expected for this formal, then
6601 -- this will not be considered a candidate operation
6602 -- for the simple pool, so we unset OK_Formal so that
6603 -- the op and any later formals will be ignored.
6610 else
6611 Error_Msg_NE
6618 -- Issue error if formal's mode is not the expected one
6621 Error_Msg_N
6623 Pool_Op_Formal);
6626 -- Advance to the next formal
6631 ------------------------------------
6632 -- Validate_Simple_Pool_Operation --
6633 ------------------------------------
6635 procedure Validate_Simple_Pool_Operation
6637 is
6643 begin
6644 pragma Assert
6646 Name_Deallocate,
6647 Name_Storage_Size));
6651 -- For each homonym declared immediately in the scope
6652 -- of the simple storage pool type, determine whether
6653 -- the homonym is an operation of the pool type, and,
6654 -- if so, check that its profile is as expected for
6655 -- a simple pool operation of that name.
6661 then
6666 -- The first parameter must be of the pool type
6667 -- in order for the operation to qualify.
6670 Validate_Simple_Pool_Op_Formal
6673 else
6674 Validate_Simple_Pool_Op_Formal
6679 -- If another operation with this name has already
6680 -- been located for the type, then flag an error,
6681 -- since we only allow the type to have a single
6682 -- such primitive.
6685 Error_Msg_NE
6690 -- In the case of Allocate and Deallocate, a formal
6691 -- of type System.Address is required.
6694 Validate_Simple_Pool_Op_Formal
6699 Validate_Simple_Pool_Op_Formal
6704 -- In the case of Allocate and Deallocate, formals
6705 -- of type Storage_Count are required as the third
6706 -- and fourth parameters.
6709 Validate_Simple_Pool_Op_Formal
6712 Validate_Simple_Pool_Op_Formal
6717 -- If no mismatched formals have been found (Is_OK)
6718 -- and no excess formals are present, then this
6719 -- operation has been validated, so record it.
6729 -- There must be a valid Allocate operation for the type,
6730 -- so issue an error if none was found.
6734 then
6740 -- Simple pool operations can't be abstract
6743 Error_Msg_N
6748 -- The Storage_Size operation must be a function with
6749 -- Storage_Count as its result type.
6753 Error_Msg_N
6757 Error_Msg_NE
6762 -- Allocate and Deallocate must be procedures
6765 Error_Msg_N
6771 -- Start of processing for Validate_Simple_Pool_Ops
6773 begin
6781 -- Now that all types from which E may depend are frozen, see if the
6782 -- size is known at compile time, if it must be unsigned, or if
6783 -- strict alignment is required
6792 -- Do not allow a size clause for a type which does not have a size
6793 -- that is known at compile time
6797 then
6798 -- Suppress this message if errors posted on E, even if we are
6799 -- in all errors mode, since this is often a junk message
6802 Error_Msg_N
6808 -- Now we set/verify the representation information, in particular
6809 -- the size and alignment values. This processing is not required for
6810 -- generic types, since generic types do not play any part in code
6811 -- generation, and so the size and alignment values for such types
6812 -- are irrelevant. Ditto for types declared within a generic unit,
6813 -- which may have components that depend on generic parameters, and
6814 -- that will be recreated in an instance.
6819 -- Otherwise we call the layout procedure
6821 else
6825 -- If this is an access to subprogram whose designated type is itself
6826 -- a subprogram type, the return type of this anonymous subprogram
6827 -- type must be decorated as well.
6831 then
6835 -- If the type has a Defaut_Value/Default_Component_Value aspect,
6836 -- this is where we analye the expression (after the type is frozen,
6837 -- since in the case of Default_Value, we are analyzing with the
6838 -- type itself, and we treat Default_Component_Value similarly for
6839 -- the sake of uniformity).
6842 declare
6847 begin
6852 else
6863 Flag_Non_Static_Expr
6870 -- End of freeze processing for type entities
6873 -- Here is where we logically freeze the current entity. If it has a
6874 -- freeze node, then this is the point at which the freeze node is
6875 -- linked into the result list.
6879 -- If a freeze node is already allocated, use it, otherwise allocate
6880 -- a new one. The preallocation happens in the case of anonymous base
6881 -- types, where we preallocate so that we can set First_Subtype_Link.
6882 -- Note that we reset the Sloc to the current freeze location.
6888 else
6899 -- A final pass over record types with discriminants. If the type
6900 -- has an incomplete declaration, there may be constrained access
6901 -- subtypes declared elsewhere, which do not depend on the discrimi-
6902 -- nants of the type, and which are used as component types (i.e.
6903 -- the full view is a recursive type). The designated types of these
6904 -- subtypes can only be elaborated after the type itself, and they
6905 -- need an itype reference.
6908 declare
6913 begin
6923 then
6935 -- When a type is frozen, the first subtype of the type is frozen as
6936 -- well (RM 13.14(15)). This has to be done after freezing the type,
6937 -- since obviously the first subtype depends on its own base type.
6942 -- If we just froze a tagged non-class wide record, then freeze the
6943 -- corresponding class-wide type. This must be done after the tagged
6944 -- type itself is frozen, because the class-wide type refers to the
6945 -- tagged type which generates the class.
6950 then
6957 -- If subprogram has address clause then reset Is_Public flag, since we
6958 -- do not want the backend to generate external references.
6963 then
6967 -- The Ghost mode of the enclosing context is ignored, while the
6968 -- entity being frozen is living. Insert the freezing action prior
6969 -- to the start of the enclosing ignored Ghost region. As a result
6970 -- the freezeing action will be preserved when the ignored Ghost
6971 -- context is eliminated. The insertion must take place even when
6972 -- the context is a spec expression, otherwise "Handling of Default
6973 -- and Per-Object Expressions" will suppress the insertion, and the
6974 -- freeze node will be dropped on the floor.
6979 then
6980 Insert_Actions
6994 -----------------------------
6995 -- Freeze_Enumeration_Type --
6996 -----------------------------
6999 begin
7000 -- By default, if no size clause is present, an enumeration type with
7001 -- Convention C is assumed to interface to a C enum and has integer
7002 -- size, except for a boolean type because it is assumed to interface
7003 -- to _Bool introduced in C99. This applies to types. For subtypes,
7004 -- verify that its base type has no size clause either. Treat other
7005 -- foreign conventions in the same way, and also make sure alignment
7006 -- is set right.
7014 -- Don't do this if Short_Enums on target
7016 and then not Target_Short_Enums
7017 then
7021 -- Normal Ada case or size clause present or not Long_C_Enums on target
7023 else
7024 -- If the enumeration type interfaces to C, and it has a size clause
7025 -- that specifies less than int size, it warrants a warning. The
7026 -- user may intend the C type to be an enum or a char, so this is
7027 -- not by itself an error that the Ada compiler can detect, but it
7028 -- it is a worth a heads-up. For Boolean and Character types we
7029 -- assume that the programmer has the proper C type in mind.
7037 -- Don't do this if Short_Enums on target
7039 and then not Target_Short_Enums
7040 then
7041 Error_Msg_N
7049 -----------------------
7050 -- Freeze_Expression --
7051 -----------------------
7056 -- If the expression is an array aggregate, the type of the component
7057 -- expressions is also frozen. If the component type is an access type
7058 -- and the expressions include allocators, the designed type is frozen
7059 -- as well.
7062 -- Given an N_Handled_Sequence_Of_Statements node N, determines whether
7063 -- it is the handled statement sequence of an expander-generated
7064 -- subprogram (init proc, stream subprogram, or renaming as body).
7065 -- If so, this is not a freezing context.
7067 -----------------------------------------
7068 -- Find_Aggregate_Component_Desig_Type --
7069 -----------------------------------------
7075 begin
7101 ----------------------
7102 -- In_Expanded_Body --
7103 ----------------------
7109 begin
7112 else
7119 else
7122 -- The following are expander-created bodies, or bodies that
7123 -- are not freeze points.
7132 N_Subprogram_Renaming_Declaration,
7133 N_Expression_Function))
7134 then
7136 else
7142 -- Local variables
7153 -- This flag is set true if the entity must be frozen outside the
7154 -- current subprogram. This happens in the case of expander generated
7155 -- subprograms (_Init_Proc, _Input, _Output, _Read, _Write) which do
7156 -- not freeze all entities like other bodies, but which nevertheless
7157 -- may reference entities that have to be frozen before the body and
7158 -- obviously cannot be frozen inside the body.
7161 -- This entity is set if we are inside a subprogram body and the frozen
7162 -- entity is defined in the enclosing scope of this subprogram. In such
7163 -- case we must skip the subprogram body when climbing the parents chain
7164 -- to locate the correct placement for the freezing node.
7166 -- Start of processing for Freeze_Expression
7168 begin
7169 -- Immediate return if freezing is inhibited. This flag is set by the
7170 -- analyzer to stop freezing on generated expressions that would cause
7171 -- freezing if they were in the source program, but which are not
7172 -- supposed to freeze, since they are created.
7178 -- If expression is non-static, then it does not freeze in a default
7179 -- expression, see section "Handling of Default Expressions" in the
7180 -- spec of package Sem for further details. Note that we have to make
7181 -- sure that we actually have a real expression (if we have a subtype
7182 -- indication, we can't test Is_OK_Static_Expression). However, we
7183 -- exclude the case of the prefix of an attribute of a static scalar
7184 -- subtype from this early return, because static subtype attributes
7185 -- should always cause freezing, even in default expressions, but
7186 -- the attribute may not have been marked as static yet (because in
7187 -- Resolve_Attribute, the call to Eval_Attribute follows the call of
7188 -- Freeze_Expression on the prefix).
7190 if In_Spec_Exp
7197 then
7201 -- Freeze type of expression if not frozen already
7209 -- Base type may be an derived numeric type that is frozen at the
7210 -- point of declaration, but first_subtype is still unfrozen.
7217 -- For entity name, freeze entity if not frozen already. A special
7218 -- exception occurs for an identifier that did not come from source.
7219 -- We don't let such identifiers freeze a non-internal entity, i.e.
7220 -- an entity that did come from source, since such an identifier was
7221 -- generated by the expander, and cannot have any semantic effect on
7222 -- the freezing semantics. For example, this stops the parameter of
7223 -- an initialization procedure from freezing the variable.
7230 then
7237 else
7241 -- For an allocator freeze designated type if not frozen already
7243 -- For an aggregate whose component type is an access type, freeze the
7244 -- designated type now, so that its freeze does not appear within the
7245 -- loop that might be created in the expansion of the aggregate. If the
7246 -- designated type is a private type without full view, the expression
7247 -- cannot contain an allocator, so the type is not frozen.
7249 -- For a function, we freeze the entity when the subprogram declaration
7250 -- is frozen, but a function call may appear in an initialization proc.
7251 -- before the declaration is frozen. We need to generate the extra
7252 -- formals, if any, to ensure that the expansion of the call includes
7253 -- the proper actuals. This only applies to Ada subprograms, not to
7254 -- imported ones.
7265 then
7266 -- Check whether aggregate includes allocators
7271 when N_Indexed_Component
7272 | N_Selected_Component
7273 | N_Slice
7274 =>
7284 then
7295 then
7299 -- All done if nothing needs freezing
7304 then
7308 -- Check if we are inside a subprogram body and the frozen entity is
7309 -- defined in the enclosing scope of this subprogram. In such case we
7310 -- must skip the subprogram when climbing the parents chain to locate
7311 -- the correct placement for the freezing node.
7313 -- This is not needed for default expressions and other spec expressions
7314 -- in generic units since the Move_Freeze_Nodes mechanism (sem_ch12.adb)
7315 -- takes care of placing them at the proper place, after the generic
7316 -- unit.
7321 then
7322 declare
7325 begin
7328 loop
7342 -- Examine the enclosing context by climbing the parent chain
7344 -- If we identified that we must freeze the entity outside of a given
7345 -- subprogram then we just climb up to that subprogram checking if some
7346 -- enclosing node is marked as Must_Not_Freeze (since in such case we
7347 -- must not freeze yet this entity).
7352 loop
7353 -- Do not freeze the current expression if another expression in
7354 -- the chain of parents must not be frozen.
7362 -- If we don't have a parent, then we are not in a well-formed
7363 -- tree. This is an unusual case, but there are some legitimate
7364 -- situations in which this occurs, notably when the expressions
7365 -- in the range of a type declaration are resolved. We simply
7366 -- ignore the freeze request in this case.
7372 exit when
7375 Freeze_Outside_Subp;
7380 -- Otherwise the traversal serves two purposes - to detect scenarios
7381 -- where freezeing is not needed and to find the proper insertion point
7382 -- for the freeze nodes. Although somewhat similar to Insert_Actions,
7383 -- this traversal is freezing semantics-sensitive. Inserting freeze
7384 -- nodes blindly in the tree may result in types being frozen too early.
7386 else
7387 loop
7388 -- Do not freeze the current expression if another expression in
7389 -- the chain of parents must not be frozen.
7397 -- If we don't have a parent, then we are not in a well-formed
7398 -- tree. This is an unusual case, but there are some legitimate
7399 -- situations in which this occurs, notably when the expressions
7400 -- in the range of a type declaration are resolved. We simply
7401 -- ignore the freeze request in this case. Is this right ???
7407 -- See if we have got to an appropriate point in the tree
7411 -- A special test for the exception of (RM 13.14(8)) for the
7412 -- case of per-object expressions (RM 3.8(18)) occurring in
7413 -- component definition or a discrete subtype definition. Note
7414 -- that we test for a component declaration which includes both
7415 -- cases we are interested in, and furthermore the tree does
7416 -- not have explicit nodes for either of these two constructs.
7420 -- The case we want to test for here is an identifier that
7421 -- is a per-object expression, this is either a discriminant
7422 -- that appears in a context other than the component
7423 -- declaration or it is a reference to the type of the
7424 -- enclosing construct.
7426 -- For either of these cases, we skip the freezing
7428 if not In_Spec_Expression
7431 then
7432 -- We recognize the discriminant case by just looking for
7433 -- a reference to a discriminant. It can only be one for
7434 -- the enclosing construct. Skip freezing in this case.
7439 -- For the case of a reference to the enclosing record,
7440 -- (or task or protected type), we look for a type that
7441 -- matches the current scope.
7448 -- If we have an enumeration literal that appears as the choice
7449 -- in the aggregate of an enumeration representation clause,
7450 -- then freezing does not occur (RM 13.14(10)).
7454 -- The case we are looking for is an enumeration literal
7458 then
7459 -- If enumeration literal appears directly as the choice,
7460 -- do not freeze (this is the normal non-overloaded case)
7464 then
7467 -- If enumeration literal appears as the name of function
7468 -- which is the choice, then also do not freeze. This
7469 -- happens in the overloaded literal case, where the
7470 -- enumeration literal is temporarily changed to a
7471 -- function call for overloading analysis purposes.
7475 N_Component_Association
7478 then
7483 -- Normally if the parent is a handled sequence of statements,
7484 -- then the current node must be a statement, and that is an
7485 -- appropriate place to insert a freeze node.
7489 -- An exception occurs when the sequence of statements is
7490 -- for an expander generated body that did not do the usual
7491 -- freeze all operation. In this case we usually want to
7492 -- freeze outside this body, not inside it, and we skip
7493 -- past the subprogram body that we are inside.
7496 declare
7500 begin
7501 -- Freeze the entity only when it is declared inside
7502 -- the body of the expander generated procedure.
7503 -- This case is recognized by the scope of the entity
7504 -- or its type, which is either the spec for some
7505 -- enclosing body, or (in the case of init_procs,
7506 -- for which there are no separate specs) the current
7507 -- scope.
7513 or else
7515 then
7521 then
7526 -- An expression function may act as a completion of
7527 -- a function declaration. As such, it can reference
7528 -- entities declared between the two views:
7530 -- Hidden []; -- 1
7531 -- function F return ...;
7532 -- private
7533 -- function Hidden return ...;
7534 -- function F return ... is (Hidden); -- 2
7536 -- Refering to the example above, freezing the
7537 -- expression of F (2) would place Hidden's freeze
7538 -- node (1) in the wrong place. Avoid explicit
7539 -- freezing and let the usual scenarios do the job
7540 -- (for example, reaching the end of the private
7541 -- declarations, or a call to F.)
7544 then
7547 -- Freeze outside the body
7549 else
7555 -- Here if normal case where we are in handled statement
7556 -- sequence and want to do the insertion right there.
7558 else
7562 -- If parent is a body or a spec or a block, then the current
7563 -- node is a statement or declaration and we can insert the
7564 -- freeze node before it.
7566 when N_Block_Statement
7567 | N_Entry_Body
7568 | N_Package_Body
7569 | N_Package_Specification
7570 | N_Protected_Body
7571 | N_Subprogram_Body
7572 | N_Task_Body
7573 =>
7576 -- The expander is allowed to define types in any statements
7577 -- list, so any of the following parent nodes also mark a
7578 -- freezing point if the actual node is in a list of
7579 -- statements or declarations.
7581 when N_Abortable_Part
7582 | N_Accept_Alternative
7583 | N_And_Then
7584 | N_Case_Statement_Alternative
7585 | N_Compilation_Unit_Aux
7586 | N_Conditional_Entry_Call
7587 | N_Delay_Alternative
7588 | N_Elsif_Part
7589 | N_Entry_Call_Alternative
7590 | N_Exception_Handler
7591 | N_Extended_Return_Statement
7592 | N_Freeze_Entity
7593 | N_If_Statement
7594 | N_Or_Else
7595 | N_Selective_Accept
7596 | N_Triggering_Alternative
7597 =>
7600 -- Freeze nodes produced by an expression coming from the
7601 -- Actions list of a N_Expression_With_Actions node must remain
7602 -- within the Actions list. Inserting the freeze nodes further
7603 -- up the tree may lead to use before declaration issues in the
7604 -- case of array types.
7609 then
7613 -- Note: N_Loop_Statement is a special case. A type that
7614 -- appears in the source can never be frozen in a loop (this
7615 -- occurs only because of a loop expanded by the expander), so
7616 -- we keep on going. Otherwise we terminate the search. Same
7617 -- is true of any entity which comes from source. (if they
7618 -- have predefined type, that type does not appear to come
7619 -- from source, but the entity should not be frozen here).
7625 -- For all other cases, keep looking at parents
7631 -- We fall through the case if we did not yet find the proper
7632 -- place in the free for inserting the freeze node, so climb.
7638 -- If the expression appears in a record or an initialization procedure,
7639 -- the freeze nodes are collected and attached to the current scope, to
7640 -- be inserted and analyzed on exit from the scope, to insure that
7641 -- generated entities appear in the correct scope. If the expression is
7642 -- a default for a discriminant specification, the scope is still void.
7643 -- The expression can also appear in the discriminant part of a private
7644 -- or concurrent type.
7646 -- If the expression appears in a constrained subcomponent of an
7647 -- enclosing record declaration, the freeze nodes must be attached to
7648 -- the outer record type so they can eventually be placed in the
7649 -- enclosing declaration list.
7651 -- The other case requiring this special handling is if we are in a
7652 -- default expression, since in that case we are about to freeze a
7653 -- static type, and the freeze scope needs to be the outer scope, not
7654 -- the scope of the subprogram with the default parameter.
7656 -- For default expressions and other spec expressions in generic units,
7657 -- the Move_Freeze_Nodes mechanism (see sem_ch12.adb) takes care of
7658 -- placing them at the proper place, after the generic unit.
7661 or else Freeze_Outside
7666 then
7667 declare
7672 begin
7685 -- The current scope may be that of a constrained component of
7686 -- an enclosing record declaration, or of a loop of an enclosing
7687 -- quantified expression, which is above the current scope in the
7688 -- scope stack. Indeed in the context of a quantified expression,
7689 -- a scope is created and pushed above the current scope in order
7690 -- to emulate the loop-like behavior of the quantified expression.
7691 -- If the expression is within a top-level pragma, as for a pre-
7692 -- condition on a library-level subprogram, nothing to do.
7697 N_Quantified_Expression)
7698 then
7705 Freeze_Nodes;
7706 else
7716 -- Now we have the right place to do the freezing. First, a special
7717 -- adjustment, if we are in spec-expression analysis mode, these freeze
7718 -- actions must not be thrown away (normally all inserted actions are
7719 -- thrown away in this mode. However, the freeze actions are from static
7720 -- expressions and one of the important reasons we are doing this
7721 -- special analysis is to get these freeze actions. Therefore we turn
7722 -- off the In_Spec_Expression mode to propagate these freeze actions.
7723 -- This also means they get properly analyzed and expanded.
7727 -- Freeze the designated type of an allocator (RM 13.14(13))
7733 -- Freeze type of expression (RM 13.14(10)). Note that we took care of
7734 -- the enumeration representation clause exception in the loop above.
7740 -- Freeze name if one is present (RM 13.14(11))
7746 -- Restore In_Spec_Expression flag
7751 -----------------------
7752 -- Freeze_Expr_Types --
7753 -----------------------
7755 procedure Freeze_Expr_Types
7760 is
7762 -- Build a duplicate of the expression of the return statement that has
7763 -- no defining entities shared with the original expression.
7766 -- Freeze all types referenced in the subtree rooted at Node
7768 -----------------------
7769 -- Cloned_Expression --
7770 -----------------------
7774 -- Tree traversal routine that clones the defining identifier of
7775 -- iterator and loop parameter specification nodes.
7777 --------------
7778 -- Clone_Id --
7779 --------------
7782 begin
7784 N_Loop_Parameter_Specification)
7785 then
7786 Set_Defining_Identifier
7795 -- Local variable
7799 -- Start of processing for Cloned_Expression
7801 begin
7802 -- We must duplicate the expression with semantic information to
7803 -- inherit the decoration of global entities in generic instances.
7804 -- Set the parent of the new node to be the parent of the original
7805 -- to get the proper context, which is needed for complete error
7806 -- reporting and for semantic analysis.
7810 -- Replace the defining identifier of iterators and loop param
7811 -- specifications by a clone to ensure that the cloned expression
7812 -- and the original expression don't have shared identifiers;
7813 -- otherwise, as part of the preanalysis of the expression, these
7814 -- shared identifiers may be left decorated with itypes which
7815 -- will not be available in the tree passed to the backend.
7822 ----------------------
7823 -- Freeze_Type_Refs --
7824 ----------------------
7828 -- Check that Typ is fully declared and freeze it if so
7830 ---------------------------
7831 -- Check_And_Freeze_Type --
7832 ---------------------------
7835 begin
7836 -- Skip Itypes created by the preanalysis, and itypes whose
7837 -- scope is another type (i.e. component subtypes that depend
7838 -- on a discriminant),
7843 then
7847 -- This provides a better error message than generating primitives
7848 -- whose compilation fails much later. Refine the error message if
7849 -- possible.
7856 then
7860 else
7865 -- Start of processing for Freeze_Type_Refs
7867 begin
7868 -- Check that a type referenced by an entity can be frozen
7873 -- Check that the enclosing record type can be frozen
7879 -- Freezing an access type does not freeze the designated type, but
7880 -- freezing conversions between access to interfaces requires that
7881 -- the interface types themselves be frozen, so that dispatch table
7882 -- entities are properly created.
7884 -- Unclear whether a more general rule is needed ???
7889 then
7893 -- An implicit dereference freezes the designated type. In the case
7894 -- of a dispatching call whose controlling argument is an access
7895 -- type, the dereference is not made explicit, so we must check for
7896 -- such a call and freeze the designated type.
7903 then
7907 -- No point in posting several errors on the same expression
7911 else
7918 -- Local variables
7924 -- Start of processing for Freeze_Expr_Types
7926 begin
7927 -- Preanalyze a duplicate of the expression to have available the
7928 -- minimum decoration needed to locate referenced unfrozen types
7929 -- without adding any decoration to the function expression.
7931 -- This routine is also applied to expressions in the contract for
7932 -- the subprogram. If that happens when expanding the code for
7933 -- pre/postconditions during expansion of the subprogram body, the
7934 -- subprogram is already installed.
7941 End_Scope;
7942 else
7946 -- Restore certain attributes of Def_Id since the preanalysis may
7947 -- have introduced itypes to this scope, thus modifying attributes
7948 -- First_Entity and Last_Entity.
7957 -- Freeze all types referenced in the expression
7962 -----------------------------
7963 -- Freeze_Fixed_Point_Type --
7964 -----------------------------
7966 -- Certain fixed-point types and subtypes, including implicit base types
7967 -- and declared first subtypes, have not yet set up a range. This is
7968 -- because the range cannot be set until the Small and Size values are
7969 -- known, and these are not known till the type is frozen.
7971 -- To signal this case, Scalar_Range contains an unanalyzed syntactic range
7972 -- whose bounds are unanalyzed real literals. This routine will recognize
7973 -- this case, and transform this range node into a properly typed range
7974 -- with properly analyzed and resolved values.
7991 -- Save original bounds (for shaving tests)
7994 -- Actual size chosen
7997 -- Returns size of type with given bounds. Also leaves these
7998 -- bounds set as the current bounds of the Typ.
8000 -----------
8001 -- Fsize --
8002 -----------
8005 begin
8011 -- Start of processing for Freeze_Fixed_Point_Type
8013 begin
8014 -- The type, or its first subtype if we are freezing the anonymous
8015 -- base, may have a delayed Small aspect. It must be analyzed now,
8016 -- so that all characteristics of the type (size, bounds) can be
8017 -- computed and validated in the call to Minimum_Size that follows.
8024 -- If Esize of a subtype has not previously been set, set it now
8031 else
8036 -- Immediate return if the range is already analyzed. This means that
8037 -- the range is already set, and does not need to be computed by this
8038 -- routine.
8044 -- Immediate return if either of the bounds raises Constraint_Error
8048 then
8058 -- Ordinary fixed-point case
8062 -- For the ordinary fixed-point case, we are allowed to fudge the
8063 -- end-points up or down by small. Generally we prefer to fudge up,
8064 -- i.e. widen the bounds for non-model numbers so that the end points
8065 -- are included. However there are cases in which this cannot be
8066 -- done, and indeed cases in which we may need to narrow the bounds.
8067 -- The following circuit makes the decision.
8069 -- Note: our terminology here is that Incl_EP means that the bounds
8070 -- are widened by Small if necessary to include the end points, and
8071 -- Excl_EP means that the bounds are narrowed by Small to exclude the
8072 -- end-points if this reduces the size.
8074 -- Note that in the Incl case, all we care about is including the
8075 -- end-points. In the Excl case, we want to narrow the bounds as
8076 -- much as permitted by the RM, to give the smallest possible size.
8093 begin
8094 -- First step. Base types are required to be symmetrical. Right
8095 -- now, the base type range is a copy of the first subtype range.
8096 -- This will be corrected before we are done, but right away we
8097 -- need to deal with the case where both bounds are non-negative.
8098 -- In this case, we set the low bound to the negative of the high
8099 -- bound, to make sure that the size is computed to include the
8100 -- required sign. Note that we do not need to worry about the
8101 -- case of both bounds negative, because the sign will be dealt
8102 -- with anyway. Furthermore we can't just go making such a bound
8103 -- symmetrical, since in a twos-complement system, there is an
8104 -- extra negative value which could not be accommodated on the
8105 -- positive side.
8110 then
8115 -- Compute the fudged bounds. If the bound is a model number, (or
8116 -- greater if given low bound, smaller if high bound) then we do
8117 -- nothing to include it, but we are allowed to backoff to the
8118 -- next adjacent model number when we exclude it. If it is not a
8119 -- model number then we straddle the two values with the model
8120 -- numbers on either side.
8126 else
8130 -- The low value excluding the end point is Small greater, but
8131 -- we do not do this exclusion if the low value is positive,
8132 -- since it can't help the size and could actually hurt by
8133 -- crossing the high bound.
8138 -- If the value went from negative to zero, then we have the
8139 -- case where Loval_Incl_EP is the model number just below
8140 -- zero, so we want to stick to the negative value for the
8141 -- base type to maintain the condition that the size will
8142 -- include signed values.
8146 then
8150 else
8154 -- Similar processing for upper bound and high value
8160 else
8166 else
8170 -- One further adjustment is needed. In the case of subtypes, we
8171 -- cannot go outside the range of the base type, or we get
8172 -- peculiarities, and the base type range is already set. This
8173 -- only applies to the Incl values, since clearly the Excl values
8174 -- are already as restricted as they are allowed to be.
8181 -- Get size including and excluding end points
8186 -- No need to exclude end-points if it does not reduce size
8196 -- Now we set the actual size to be used. We want to use the
8197 -- bounds fudged up to include the end-points but only if this
8198 -- can be done without violating a specifically given size
8199 -- size clause or causing an unacceptable increase in size.
8201 -- Case of size clause given
8205 -- Use the inclusive size only if it is consistent with
8206 -- the explicitly specified size.
8213 -- If the inclusive size is too large, we try excluding
8214 -- the end-points (will be caught later if does not work).
8216 else
8222 -- Case of size clause not given
8224 else
8225 -- If we have a base type whose corresponding first subtype
8226 -- has an explicit size that is large enough to include our
8227 -- end-points, then do so. There is no point in working hard
8228 -- to get a base type whose size is smaller than the specified
8229 -- size of the first subtype.
8235 then
8240 -- If excluding the end-points makes the size smaller and
8241 -- results in a size of 8,16,32,64, then we take the smaller
8242 -- size. For the 64 case, this is compulsory. For the other
8243 -- cases, it seems reasonable. We like to include end points
8244 -- if we can, but not at the expense of moving to the next
8245 -- natural boundary of size.
8249 then
8254 -- Otherwise we can definitely include the end points
8256 else
8262 -- One pathological case: normally we never fudge a low bound
8263 -- down, since it would seem to increase the size (if it has
8264 -- any effect), but for ranges containing single value, or no
8265 -- values, the high bound can be small too large. Consider:
8267 -- type t is delta 2.0**(-14)
8268 -- range 131072.0 .. 0;
8270 -- That lower bound is *just* outside the range of 32 bits, and
8271 -- does need fudging down in this case. Note that the bounds
8272 -- will always have crossed here, since the high bound will be
8273 -- fudged down if necessary, as in the case of:
8275 -- type t is delta 2.0**(-14)
8276 -- range 131072.0 .. 131072.0;
8278 -- So we detect the situation by looking for crossed bounds,
8279 -- and if the bounds are crossed, and the low bound is greater
8280 -- than zero, we will always back it off by small, since this
8281 -- is completely harmless.
8288 -- And of course, we need to do exactly the same parallel
8289 -- fudge for flat ranges in the negative region.
8302 -- For the decimal case, none of this fudging is required, since there
8303 -- are no end-point problems in the decimal case (the end-points are
8304 -- always included).
8306 else
8310 -- At this stage, the actual size has been calculated and the proper
8311 -- required bounds are stored in the low and high bounds.
8315 Error_Msg_N
8317 Typ);
8321 -- Check size against explicit given size
8327 Error_Msg_NE
8331 else
8335 -- Increase size to next natural boundary if no size clause given
8337 else
8344 else
8352 -- If we have a base type, then expand the bounds so that they extend to
8353 -- the full width of the allocated size in bits, to avoid junk range
8354 -- checks on intermediate computations.
8361 -- Final step is to reanalyze the bounds using the proper type
8362 -- and set the Corresponding_Integer_Value fields of the literals.
8368 -- Resolve with universal fixed if the base type, and the base type if
8369 -- it is a subtype. Note we can't resolve the base type with itself,
8370 -- that would be a reference before definition.
8374 else
8378 -- Set corresponding integer value for bound
8380 Set_Corresponding_Integer_Value
8383 -- Similar processing for high bound
8391 else
8395 Set_Corresponding_Integer_Value
8398 -- Set type of range to correspond to bounds
8402 -- Set Esize to calculated size if not set already
8408 -- Set RM_Size if not already set. If already set, check value
8410 declare
8413 begin
8418 Error_Msg_NE
8423 else
8428 -- Check for shaving
8432 -- In SPARK mode the given bounds must be strictly representable
8436 Error_Msg_NE
8442 Error_Msg_NE
8447 else
8449 Error_Msg_N
8451 Error_Msg_N
8456 Error_Msg_N
8458 Typ);
8459 Error_Msg_N
8466 ------------------
8467 -- Freeze_Itype --
8468 ------------------
8473 begin
8482 --------------------------
8483 -- Freeze_Static_Object --
8484 --------------------------
8489 -- Exception raised if the type of a static object cannot be made
8490 -- static. This happens if the type depends on non-global objects.
8493 -- Called to ensure that an expression used as part of a type definition
8494 -- is statically allocatable, which means that the expression type is
8495 -- statically allocatable, and the expression is either static, or a
8496 -- reference to a library level constant.
8499 -- Called to mark a type as static, checking that it is possible
8500 -- to set the type as static. If it is not possible, then the
8501 -- exception Cannot_Be_Static is raised.
8503 -----------------------------
8504 -- Ensure_Expression_Is_SA --
8505 -----------------------------
8510 begin
8522 then
8530 -----------------------
8531 -- Ensure_Type_Is_SA --
8532 -----------------------
8538 begin
8539 -- If type is library level, we are all set
8545 -- We are also OK if the type already marked as statically allocated,
8546 -- which means we processed it before.
8552 -- Mark type as statically allocated
8556 -- Check that it is safe to statically allocate this type
8574 declare
8578 begin
8590 else
8599 then
8618 else
8623 -- Start of processing for Freeze_Static_Object
8625 begin
8628 exception
8631 -- If the object that cannot be static is imported or exported, then
8632 -- issue an error message saying that this object cannot be imported
8633 -- or exported. If it has an address clause it is an overlay in the
8634 -- current partition and the static requirement is not relevant.
8635 -- Do not issue any error message when ignoring rep clauses.
8642 Error_Msg_N
8646 -- Otherwise must be exported, something is wrong if compiler
8647 -- is marking something as statically allocated which cannot be).
8650 Error_Msg_N
8655 -----------------------
8656 -- Freeze_Subprogram --
8657 -----------------------
8661 -- Set the conventions of all anonymous access-to-subprogram formals and
8662 -- result subtype of subprogram Subp_Id to the convention of Subp_Id.
8664 ----------------------------
8665 -- Set_Profile_Convention --
8666 ----------------------------
8672 -- Set the convention of anonymous access-to-subprogram type Typ and
8673 -- its designated type to Conv.
8675 -------------------------
8676 -- Set_Type_Convention --
8677 -------------------------
8680 begin
8681 -- Set the convention on both the anonymous access-to-subprogram
8682 -- type and the subprogram type it points to because both types
8683 -- participate in conformance-related checks.
8691 -- Local variables
8695 -- Start of processing for Set_Profile_Convention
8697 begin
8709 -- Local variables
8714 -- Start of processing for Freeze_Subprogram
8716 begin
8717 -- Subprogram may not have an address clause unless it is imported
8721 Error_Msg_N
8727 -- Reset the Pure indication on an imported subprogram unless an
8728 -- explicit Pure_Function pragma was present or the subprogram is an
8729 -- intrinsic. We do this because otherwise it is an insidious error
8730 -- to call a non-pure function from pure unit and have calls
8731 -- mysteriously optimized away. What happens here is that the Import
8732 -- can bypass the normal check to ensure that pure units call only pure
8733 -- subprograms.
8735 -- The reason for the intrinsic exception is that in general, intrinsic
8736 -- functions (such as shifts) are pure anyway. The only exceptions are
8737 -- the intrinsics in GNAT.Source_Info, and that unit is not marked Pure
8738 -- in any case, so no problem arises.
8744 then
8748 -- We also reset the Pure indication on a subprogram with an Address
8749 -- parameter, because the parameter may be used as a pointer and the
8750 -- referenced data may change even if the address value does not.
8752 -- Note that if the programmer gave an explicit Pure_Function pragma,
8753 -- then we believe the programmer, and leave the subprogram Pure. We
8754 -- also suppress this check on run-time files.
8760 then
8764 -- Ensure that all anonymous access-to-subprogram types inherit the
8765 -- convention of their related subprogram (RM 6.3.1 13.1/3). This is
8766 -- not done for a defaulted convention Ada because those types also
8767 -- default to Ada. Convention Protected must not be propagated when
8768 -- the subprogram is an entry because this would be illegal. The only
8769 -- way to force convention Protected on these kinds of types is to
8770 -- include keyword "protected" in the access definition.
8774 then
8778 -- For non-foreign convention subprograms, this is where we create
8779 -- the extra formals (for accessibility level and constrained bit
8780 -- information). We delay this till the freeze point precisely so
8781 -- that we know the convention.
8790 -- If this is convention Ada and a Valued_Procedure, that's odd
8795 and then Warn_On_Export_Import
8796 then
8797 Error_Msg_N
8802 -- Case of foreign convention
8804 else
8807 -- For foreign conventions, warn about return of unconstrained array
8812 -- If no return type, probably some other error, e.g. a
8813 -- missing full declaration, so ignore.
8818 -- If the return type is generic, we have emitted a warning
8819 -- earlier on, and there is nothing else to check here. Specific
8820 -- instantiations may lead to erroneous behavior.
8825 -- Display warning if returning unconstrained array
8830 -- Check appropriate warning is enabled (should we check for
8831 -- Warnings (Off) on specific entities here, probably so???)
8833 and then Warn_On_Export_Import
8834 then
8835 Error_Msg_N
8842 -- If any of the formals for an exported foreign convention
8843 -- subprogram have defaults, then emit an appropriate warning since
8844 -- this is odd (default cannot be used from non-Ada code)
8849 if Warn_On_Export_Import
8851 then
8852 Error_Msg_N
8862 -- Pragma Inline_Always is disallowed for dispatching subprograms
8863 -- because the address of such subprograms is saved in the dispatch
8864 -- table to support dispatching calls, and dispatching calls cannot
8865 -- be inlined. This is consistent with the restriction against using
8866 -- 'Access or 'Address on an Inline_Always subprogram.
8870 then
8871 Error_Msg_N
8875 -- Because of the implicit representation of inherited predefined
8876 -- operators in the front-end, the overriding status of the operation
8877 -- may be affected when a full view of a type is analyzed, and this is
8878 -- not captured by the analysis of the corresponding type declaration.
8879 -- Therefore the correctness of a not-overriding indicator must be
8880 -- rechecked when the subprogram is frozen.
8884 then
8888 if Modify_Tree_For_C
8894 then
8899 ----------------------
8900 -- Is_Fully_Defined --
8901 ----------------------
8904 begin
8913 then
8914 -- Verify that the record type has no components with private types
8915 -- without completion.
8917 declare
8920 begin
8932 -- For the designated type of an access to subprogram, all types in
8933 -- the profile must be fully defined.
8936 declare
8939 begin
8952 else
8958 ---------------------------------
8959 -- Process_Default_Expressions --
8960 ---------------------------------
8962 procedure Process_Default_Expressions
8965 is
8972 begin
8975 -- A subprogram instance and its associated anonymous subprogram share
8976 -- their signature. The default expression functions are defined in the
8977 -- wrapper packages for the anonymous subprogram, and should not be
8978 -- generated again for the instance.
8983 then
8991 -- We work with a copy of the default expression because we
8992 -- do not want to disturb the original, since this would mess
8993 -- up the conformance checking.
8997 -- The analysis of the expression may generate insert actions,
8998 -- which of course must not be executed. We wrap those actions
8999 -- in a procedure that is not called, and later on eliminated.
9000 -- The following cases have no side effects, and are analyzed
9001 -- directly.
9005 N_Integer_Literal,
9006 N_Character_Literal,
9007 N_String_Literal,
9008 N_Real_Literal)
9012 then
9013 -- If there is no default function, we must still do a full
9014 -- analyze call on the default value, to ensure that all error
9015 -- checks are performed, e.g. those associated with static
9016 -- evaluation. Note: this branch will always be taken if the
9017 -- analyzer is turned off (but we still need the error checks).
9019 -- Note: the setting of parent here is to meet the requirement
9020 -- that we can only analyze the expression while attached to
9021 -- the tree. Really the requirement is that the parent chain
9022 -- be set, we don't actually need to be in the tree.
9027 -- Default expressions are resolved with their own type if the
9028 -- context is generic, to avoid anomalies with private types.
9032 else
9036 -- If that resolved expression will raise constraint error,
9037 -- then flag the default value as raising constraint error.
9038 -- This allows a proper error message on the calls.
9044 -- If the default is a parameterless call, we use the name of
9045 -- the called function directly, and there is no body to build.
9049 then
9052 -- Else construct and analyze the body of a wrapper procedure
9053 -- that contains an object declaration to hold the expression.
9054 -- Given that this is done only to complete the analysis, it is
9055 -- simpler to build a procedure than a function which might
9056 -- involve secondary stack expansion.
9058 else
9061 Dbody :=
9063 Specification =>
9070 Object_Definition =>
9074 Handled_Statement_Sequence =>
9091 ----------------------------------------
9092 -- Set_Component_Alignment_If_Not_Set --
9093 ----------------------------------------
9096 begin
9097 -- Ignore if not base type, subtypes don't need anything
9103 -- Do not override existing representation
9114 else
9115 Set_Component_Alignment
9121 --------------------------
9122 -- Set_SSO_From_Default --
9123 --------------------------
9128 begin
9129 -- Set default SSO for an array or record base type, except in case of
9130 -- a type extension (which always inherits the SSO of its parent type).
9137 then
9138 Reversed :=
9140 or else
9145 -- For a record type, if bit order is specified explicitly,
9146 -- then do not set SSO from default if not consistent. Note that
9147 -- we do not want to look at a Bit_Order attribute definition
9148 -- for a parent: if we were to inherit Bit_Order, then both
9149 -- SSO_Set_*_By_Default flags would have been cleared already
9150 -- (by Inherit_Aspects_At_Freeze_Point).
9152 and then not
9154 and then
9157 then
9158 -- If flags cause reverse storage order, then set the result. Note
9159 -- that we would have ignored the pragma setting the non default
9160 -- storage order in any case, hence the assertion at this point.
9162 pragma Assert
9167 -- For a record type, also set reversed bit order. Note: if a bit
9168 -- order has been specified explicitly, then this is a no-op.
9177 ------------------
9178 -- Undelay_Type --
9179 ------------------
9182 begin
9186 -- Since we don't want T to have a Freeze_Node, we don't want its
9187 -- Full_View or Corresponding_Record_Type to have one either.
9189 -- ??? Fundamentally, this whole handling is unpleasant. What we really
9190 -- want is to be sure that for an Itype that's part of record R and is a
9191 -- subtype of type T, that it's frozen after the later of the freeze
9192 -- points of R and T. We have no way of doing that directly, so what we
9193 -- do is force most such Itypes to be frozen as part of freezing R via
9194 -- this procedure and only delay the ones that need to be delayed
9195 -- (mostly the designated types of access types that are defined as part
9196 -- of the record).
9202 then
9210 then
9215 ------------------
9216 -- Warn_Overlay --
9217 ------------------
9221 -- The object to which the address clause applies
9227 begin
9228 -- No warning if address clause overlay warnings are off
9234 -- No warning if there is an explicit initialization
9242 -- We only give the warning for non-imported entities of a type for
9243 -- which a non-null base init proc is defined, or for objects of access
9244 -- types with implicit null initialization, or when Normalize_Scalars
9245 -- applies and the type is scalar or a string type (the latter being
9246 -- tested for because predefined String types are initialized by inline
9247 -- code rather than by an init_proc). Note that we do not give the
9248 -- warning for Initialize_Scalars, since we suppressed initialization
9249 -- in this case. Also, do not warn if Suppress_Initialization is set
9250 -- either on the type, or on the object via pragma or aspect.
9262 then
9265 then
9270 then
9277 then
9284 -- A function call (most likely to To_Address) is probably not an
9285 -- overlay, so skip warning. Ditto if the function call was inlined
9286 -- and transformed into an entity.
9292 -- If a pragma Import follows, we assume that it is for the current
9293 -- target of the address clause, and skip the warning. There may be
9294 -- a source pragma or an aspect that specifies import and generates
9295 -- the corresponding pragma. These will indicate that the entity is
9296 -- imported and that is checked above so that the spurious warning
9297 -- (generated when the entity is frozen) will be suppressed. The
9298 -- pragma may be attached to the aspect, so it is not yet a list
9299 -- member.
9307 then
9312 -- Otherwise give warning message
9316 Error_Msg_N
9318 Nam);
9319 else
9320 Error_Msg_N
9322 Nam);
9325 -- Add friendly warning if initialization comes from a packed array
9326 -- component.
9329 declare
9332 begin
9337 then
9341 then
9342 Error_Msg_NE
9347 else
9354 Error_Msg_N
9357 Nam);