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1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- S E M _ R E S --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1992-2021, 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 ------------------------------------------------------------------------------
94 -----------------------
95 -- Local Subprograms --
96 -----------------------
98 -- Second pass (top-down) type checking and overload resolution procedures
99 -- Typ is the type required by context. These procedures propagate the
100 -- type information recursively to the descendants of N. If the node is not
101 -- overloaded, its Etype is established in the first pass. If overloaded,
102 -- the Resolve routines set the correct type. For arithmetic operators, the
103 -- Etype is the base type of the context.
105 -- Note that Resolve_Attribute is separated off in Sem_Attr
107 function Has_Applicable_User_Defined_Literal
110 -- If N is a literal or a named number, check whether Typ
111 -- has a user-defined literal aspect that can apply to N.
112 -- If present, replace N with a call to the corresponding
113 -- function and return True.
116 -- Enforce the restrictions on the use of discriminants when constraining
117 -- a component of a discriminated type (record or concurrent type).
120 -- Given a node for an operator associated with type T, check that the
121 -- operator is visible. Operators all of whose operands are universal must
122 -- be checked for visibility during resolution because their type is not
123 -- determinable based on their operands.
125 procedure Check_Fully_Declared_Prefix
128 -- Check that the type of the prefix of a dereference is not incomplete
131 -- Given a call node, Call, which is known to occur immediately within the
132 -- subprogram being called, determines whether it is a detectable case of
133 -- an infinite recursion, and if so, outputs appropriate messages. Returns
134 -- True if an infinite recursion is detected, and False otherwise.
137 -- N is the node for a logical operator. If the operator is predefined, and
138 -- the root type of the operands is Standard.Boolean, then a check is made
139 -- for restriction No_Direct_Boolean_Operators. This procedure also handles
140 -- the style check for Style_Check_Boolean_And_Or.
143 -- N is either an indexed component or a selected component. This function
144 -- returns true if the prefix refers to an object that has an address
145 -- clause (the case in which we may want to issue a warning).
148 -- Determine whether E is an access type declared by an access declaration,
149 -- and not an (anonymous) allocator type.
152 -- Utility to check whether the entity for an operator is a predefined
153 -- operator, in which case the expression is left as an operator in the
154 -- tree (else it is rewritten into a call). An instance of an intrinsic
155 -- conversion operation may be given an operator name, but is not treated
156 -- like an operator. Note that an operator that is an imported back-end
157 -- builtin has convention Intrinsic, but is expected to be rewritten into
158 -- a call, so such an operator is not treated as predefined by this
159 -- predicate.
161 procedure Preanalyze_And_Resolve
165 -- Subsidiary of public versions of Preanalyze_And_Resolve.
168 -- If a default expression in entry call N depends on the discriminants
169 -- of the task, it must be replaced with a reference to the discriminant
170 -- of the task being called.
172 procedure Resolve_Op_Concat_Arg
177 -- Internal procedure for Resolve_Op_Concat to resolve one operand of
178 -- concatenation operator. The operand is either of the array type or of
179 -- the component type. If the operand is an aggregate, and the component
180 -- type is composite, this is ambiguous if component type has aggregates.
183 -- Does the first part of the work of Resolve_Op_Concat
186 -- Does the "rest" of the work of Resolve_Op_Concat, after the left operand
187 -- has been resolved. See Resolve_Op_Concat for details.
227 function Operator_Kind
230 -- Utility to map the name of an operator into the corresponding Node. Used
231 -- by other node rewriting procedures.
234 -- Resolve actuals of call, and add default expressions for missing ones.
235 -- N is the Node_Id for the subprogram call, and Nam is the entity of the
236 -- called subprogram.
239 -- Called from Resolve_Call, when the prefix denotes an entry or element
240 -- of entry family. Actuals are resolved as for subprograms, and the node
241 -- is rebuilt as an entry call. Also called for protected operations. Typ
242 -- is the context type, which is used when the operation is a protected
243 -- function with no arguments, and the return value is indexed.
246 -- Called when P is the prefix of an indexed component, or of a selected
247 -- component, or of a slice. If P is of an access type, we unconditionally
248 -- rewrite it as an explicit dereference. This ensures that the expander
249 -- and the code generator have a fully explicit tree to work with.
252 -- A call to a user-defined intrinsic operator is rewritten as a call to
253 -- the corresponding predefined operator, with suitable conversions. Note
254 -- that this applies only for intrinsic operators that denote predefined
255 -- operators, not ones that are intrinsic imports of back-end builtins.
258 -- Ditto, for arithmetic unary operators
261 -- If an operator node resolves to a call to a user-defined operator,
262 -- rewrite the node as a function call.
264 procedure Make_Call_Into_Operator
268 -- Inverse transformation: if an operator is given in functional notation,
269 -- then after resolving the node, transform into an operator node, so that
270 -- operands are resolved properly. Recall that predefined operators do not
271 -- have a full signature and special resolution rules apply.
273 procedure Rewrite_Renamed_Operator
277 -- An operator can rename another, e.g. in an instantiation. In that
278 -- case, the proper operator node must be constructed and resolved.
281 -- The String_Literal_Subtype is built for all strings that are not
282 -- operands of a static concatenation operation. If the argument is not
283 -- a N_String_Literal node, then the call has no effect.
286 -- Build subtype of array type, with the range specified by the slice
289 -- Called after N has been resolved and evaluated, but before range checks
290 -- have been applied. This rewrites the conversion into a simpler form.
293 -- A universal_fixed expression in an universal context is unambiguous if
294 -- there is only one applicable fixed point type. Determining whether there
295 -- is only one requires a search over all visible entities, and happens
296 -- only in very pathological cases (see 6115-006).
298 function Try_User_Defined_Literal
301 -- If an operator node has a literal operand, check whether the type
302 -- of the context, or the type of the other operand has a user-defined
303 -- literal aspect that can be applied to the literal to resolve the node.
304 -- If such aspect exists, replace literal with a call to the
305 -- corresponing function and return True, return false otherwise.
307 -------------------------
308 -- Ambiguous_Character --
309 -------------------------
314 begin
318 -- First the ones in Standard
323 -- Include Wide_Wide_Character in Ada 2005 mode
329 -- Now any other types that match
339 -------------------------
340 -- Analyze_And_Resolve --
341 -------------------------
344 begin
350 begin
355 -- Versions with check(s) suppressed
357 procedure Analyze_And_Resolve
361 is
364 begin
366 declare
368 begin
374 else
375 declare
377 begin
385 and then Scope_Is_Transient
386 then
387 -- This can only happen if a transient scope was created for an inner
388 -- expression, which will be removed upon completion of the analysis
389 -- of an enclosing construct. The transient scope must have the
390 -- suppress status of the enclosing environment, not of this Analyze
391 -- call.
394 Scope_Suppress;
398 procedure Analyze_And_Resolve
401 is
404 begin
406 declare
408 begin
414 else
415 declare
417 begin
426 Scope_Suppress;
430 -------------------------------------
431 -- Has_Applicable_User_Defined_Literal --
432 -------------------------------------
434 function Has_Applicable_User_Defined_Literal
437 is
439 Literal_Aspect_Map :
459 begin
461 and then Present
463 or else
466 and then
467 Present
468 (Find_Aspect
470 then
471 Lit_Aspect :=
475 Callee :=
482 then
483 Callee :=
484 Corresponding_Primitive_Op
489 -- Handle an identifier that denotes a named number.
496 Start_String;
497 Store_String_Chars
502 else
504 Start_String;
510 Store_String_Chars
514 -- Note: Set_Etype is called below on Param1
517 Start_String;
518 Store_String_Chars
527 else
528 Error_Msg_NE
538 else
539 Param1 :=
540 Make_String_Literal
545 Call :=
546 Make_Function_Call
556 else
563 -- Conversion may be needed in case of an inherited
564 -- aspect of a derived type. For a null extension, we
565 -- use a null extension aggregate instead because the
566 -- downward type conversion would be illegal.
568 if Is_Null_Extension_Of
571 then
575 else
584 else
589 ----------------------------
590 -- Check_Discriminant_Use --
591 ----------------------------
599 begin
600 -- Any use in a spec-expression is legal
607 -- Discriminant cannot be used to constrain a scalar type
614 then
619 -- The following check catches the unusual case where a
620 -- discriminant appears within an index constraint that is part
621 -- of a larger expression within a constraint on a component,
622 -- e.g. "C : Int range 1 .. F (new A(1 .. D))". For now we only
623 -- check case of record components, and note that a similar check
624 -- should also apply in the case of discriminant constraints
625 -- below. ???
627 -- Note that the check for N_Subtype_Declaration below is to
628 -- detect the valid use of discriminants in the constraints of a
629 -- subtype declaration when this subtype declaration appears
630 -- inside the scope of a record type (which is syntactically
631 -- illegal, but which may be created as part of derived type
632 -- processing for records). See Sem_Ch3.Build_Derived_Record_Type
633 -- for more info.
637 and then not
639 and then
641 | N_Subtype_Declaration
643 then
644 Error_Msg_N
649 -- Detect a common error:
651 -- type R (D : Positive := 100) is record
652 -- Name : String (1 .. D);
653 -- end record;
655 -- The default value causes an object of type R to be allocated
656 -- with room for Positive'Last characters. The RM does not mandate
657 -- the allocation of the maximum size, but that is what GNAT does
658 -- so we should warn the programmer that there is a problem.
667 -- Return True if type T has a large enough range that any
668 -- array whose index type covered the whole range of the type
669 -- would likely raise Storage_Error.
671 ------------------------
672 -- Large_Storage_Type --
673 ------------------------
676 begin
677 -- The type is considered large if its bounds are known at
678 -- compile time and if it requires at least as many bits as
679 -- a Positive to store the possible values.
683 and then
688 -- Start of processing for Check_Large
690 begin
691 -- Check that the Disc has a large range
697 -- If the enclosing type is limited, we allocate only the
698 -- default value, not the maximum, and there is no need for
699 -- a warning.
705 -- Check that it is the high bound
709 then
713 -- Check the array allows a large range at this bound. First
714 -- find the array
728 -- Next, find the dimension
736 loop
745 -- Now, check the dimension has a large range
751 -- Warn about the danger
753 Error_Msg_N
763 -- Legal case is in index or discriminant constraint
766 | N_Discriminant_Association
767 then
769 Error_Msg_N
774 then
775 Error_Msg_N
781 -- Otherwise, context is an expression. It should not be within (i.e. a
782 -- subexpression of) a constraint for a component.
784 else
788 N_Component_Declaration | N_Subtype_Indication | N_Entry_Declaration
789 loop
795 -- If the discriminant is used in an expression that is a bound of a
796 -- scalar type, an Itype is created and the bounds are attached to
797 -- its range, not to the original subtype indication. Such use is of
798 -- course a double fault.
802 | N_Derived_Type_Definition
805 -- The constraint itself may be given by a subtype indication,
806 -- rather than by a more common discrete range.
809 and then
813 then
814 Error_Msg_N
820 --------------------------------
821 -- Check_For_Visible_Operator --
822 --------------------------------
825 begin
827 Error_Msg_NE -- CODEFIX
829 Error_Msg_N -- CODEFIX
834 ---------------------------------
835 -- Check_Fully_Declared_Prefix --
836 ---------------------------------
838 procedure Check_Fully_Declared_Prefix
841 is
842 begin
843 -- Check that the designated type of the prefix of a dereference is
844 -- not an incomplete type. This cannot be done unconditionally, because
845 -- dereferences of private types are legal in default expressions. This
846 -- case is taken care of in Check_Fully_Declared, called below. There
847 -- are also 2005 cases where it is legal for the prefix to be unfrozen.
849 -- This consideration also applies to similar checks for allocators,
850 -- qualified expressions, and type conversions.
852 -- An additional exception concerns other per-object expressions that
853 -- are not directly related to component declarations, in particular
854 -- representation pragmas for tasks. These will be per-object
855 -- expressions if they depend on discriminants or some global entity.
856 -- If the task has access discriminants, the designated type may be
857 -- incomplete at the point the expression is resolved. This resolution
858 -- takes place within the body of the initialization procedure, where
859 -- the discriminant is replaced by its discriminal.
863 then
866 -- Ada 2005 (AI-326): Tagged incomplete types allowed. The wrong usages
867 -- are handled by Analyze_Access_Attribute, Analyze_Assignment,
868 -- Analyze_Object_Renaming, and Freeze_Entity.
874 E_Incomplete_Type
876 then
878 else
883 ------------------------------
884 -- Check_Infinite_Recursion --
885 ------------------------------
889 -- Return the nearest enclosing declaration or statement that houses
890 -- arbitrary node N.
893 -- Determine whether call N invokes the related enclosing subprogram
894 -- with actuals that differ from the subprogram's formals.
897 -- Determine whether arbitrary node N denotes a conditional construct
900 -- Determine whether arbitrary node N denotes a control flow statement
901 -- or a construct that may contains such a statement.
904 -- Determine whether arbitrary node N appears immediately within the
905 -- statements of an entry or subprogram body.
908 -- Determine whether arbitrary node N appears immediately within the
909 -- body of an entry or subprogram, and is preceded by a single raise
910 -- statement.
913 -- Determine whether arbitrary node N denotes a raise statement
916 -- Determine whether arbitrary node N is the sole source statement in
917 -- the body of the enclosing subprogram.
920 -- Determine whether arbitrary node N is preceded by a control flow
921 -- statement.
924 -- Determine whether arbitrary node N appears within a conditional
925 -- construct.
927 ----------------------------------------
928 -- Enclosing_Declaration_Or_Statement --
929 ----------------------------------------
931 function Enclosing_Declaration_Or_Statement
933 is
936 begin
942 -- Prevent the search from going too far
954 --------------------------------------
955 -- Invoked_With_Different_Arguments --
956 --------------------------------------
964 begin
965 -- Determine whether the formals of the invoked subprogram are not
966 -- used as actuals in the call.
972 -- The current actual does not match the current formal
976 then
987 ------------------------------
988 -- Is_Conditional_Statement --
989 ------------------------------
992 begin
993 return
995 | N_Case_Expression
996 | N_Case_Statement
997 | N_If_Expression
998 | N_If_Statement
999 | N_Or_Else;
1002 -------------------------------
1003 -- Is_Control_Flow_Statement --
1004 -------------------------------
1007 begin
1008 -- It is assumed that all statements may affect the control flow in
1009 -- some way. A raise statement may be expanded into a non-statement
1010 -- node.
1015 --------------------------------
1016 -- Is_Immediately_Within_Body --
1017 --------------------------------
1022 begin
1023 return
1030 --------------------
1031 -- Is_Raise_Idiom --
1032 --------------------
1038 begin
1041 -- Assume that no raise statement has been seen yet
1045 -- Examine the statements preceding the input node, skipping
1046 -- internally-generated constructs.
1051 -- Multiple raise statements violate the idiom
1067 -- At this point the node must be preceded by a raise statement,
1068 -- and the raise statement has to be the sole statement within
1069 -- the enclosing entry or subprogram body.
1071 return
1078 ------------------------
1079 -- Is_Raise_Statement --
1080 ------------------------
1083 begin
1084 -- A raise statement may be transfomed into a Raise_xxx_Error node
1086 return
1091 -----------------------
1092 -- Is_Sole_Statement --
1093 -----------------------
1098 begin
1099 -- The input node appears within the statements of an entry or
1100 -- subprogram body. Examine the statements preceding the node.
1107 -- The statement is preceded by another statement or a source
1108 -- construct. This indicates that the node does not appear by
1109 -- itself.
1113 then
1123 -- The input node is within a construct nested inside the entry or
1124 -- subprogram body.
1129 ----------------------------------------
1130 -- Preceded_By_Control_Flow_Statement --
1131 ----------------------------------------
1133 function Preceded_By_Control_Flow_Statement
1135 is
1138 begin
1142 -- Examine the statements preceding the input node
1155 -- Assume that the node is part of some control flow statement
1160 ----------------------------------
1161 -- Within_Conditional_Statement --
1162 ----------------------------------
1167 begin
1173 -- Prevent the search from going too far
1185 -- Local variables
1190 -- Start of processing for Check_Infinite_Recursion
1192 begin
1193 -- The call is assumed to be safe when the enclosing subprogram is
1194 -- invoked with actuals other than its formals.
1195 --
1196 -- procedure Proc (F1 : ...; F2 : ...; ...; FN : ...) is
1197 -- begin
1198 -- ...
1199 -- Proc (A1, A2, ..., AN);
1200 -- ...
1201 -- end Proc;
1206 -- The call is assumed to be safe when the invocation of the enclosing
1207 -- subprogram depends on a conditional statement.
1208 --
1209 -- procedure Proc (F1 : ...; F2 : ...; ...; FN : ...) is
1210 -- begin
1211 -- ...
1212 -- if Some_Condition then
1213 -- Proc (F1, F2, ..., FN);
1214 -- end if;
1215 -- ...
1216 -- end Proc;
1221 -- The context of the call is assumed to be safe when the invocation of
1222 -- the enclosing subprogram is preceded by some control flow statement.
1223 --
1224 -- procedure Proc (F1 : ...; F2 : ...; ...; FN : ...) is
1225 -- begin
1226 -- ...
1227 -- if Some_Condition then
1228 -- ...
1229 -- end if;
1230 -- ...
1231 -- Proc (F1, F2, ..., FN);
1232 -- ...
1233 -- end Proc;
1238 -- Detect an idiom where the context of the call is preceded by a single
1239 -- raise statement.
1240 --
1241 -- procedure Proc (F1 : ...; F2 : ...; ...; FN : ...) is
1242 -- begin
1243 -- raise ...;
1244 -- Proc (F1, F2, ..., FN);
1245 -- end Proc;
1251 -- At this point it is certain that infinite recursion will take place
1252 -- as long as the call is executed. Detect a case where the context of
1253 -- the call is the sole source statement within the subprogram body.
1254 --
1255 -- procedure Proc (F1 : ...; F2 : ...; ...; FN : ...) is
1256 -- begin
1257 -- Proc (F1, F2, ..., FN);
1258 -- end Proc;
1259 --
1260 -- Install an explicit raise to prevent the infinite recursion.
1271 -- Otherwise infinite recursion could take place, considering other flow
1272 -- control constructs such as gotos, exit statements, etc.
1274 else
1283 ---------------------------------------
1284 -- Check_No_Direct_Boolean_Operators --
1285 ---------------------------------------
1288 begin
1291 then
1292 -- Restriction only applies to original source code
1299 -- Do style check (but skip if in instance, error is on template)
1308 ------------------------------
1309 -- Check_Parameterless_Call --
1310 ------------------------------
1316 -- If the prefix is of an access_to_subprogram type, the node must be
1317 -- rewritten as a call. Ditto if the prefix is overloaded and all its
1318 -- interpretations are access to subprograms.
1320 ---------------------------
1321 -- Prefix_Is_Access_Subp --
1322 ---------------------------
1328 begin
1329 -- If the context is an attribute reference that can apply to
1330 -- functions, this is never a parameterless call (RM 4.1.4(6)).
1334 in Name_Address | Name_Code_Address | Name_Access
1335 then
1340 return
1343 else
1348 then
1359 -- Start of processing for Check_Parameterless_Call
1361 begin
1362 -- Defend against junk stuff if errors already detected
1369 then
1376 -- If the context expects a value, and the name is a procedure, this is
1377 -- most likely a missing 'Access. Don't try to resolve the parameterless
1378 -- call, error will be caught when the outer call is analyzed.
1383 and then
1385 | N_Function_Call
1386 | N_Procedure_Call_Statement
1387 then
1391 -- Rewrite as call if overloadable entity that is (or could be, in the
1392 -- overloaded case) a function call. If we know for sure that the entity
1393 -- is an enumeration literal, we do not rewrite it.
1395 -- If the entity is the name of an operator, it cannot be a call because
1396 -- operators cannot have default parameters. In this case, this must be
1397 -- a string whose contents coincide with an operator name. Set the kind
1398 -- of the node appropriately.
1406 -- Rewrite as call if it is an explicit dereference of an expression of
1407 -- a subprogram access type, and the subprogram type is not that of a
1408 -- procedure or entry.
1410 or else
1413 -- Rewrite as call if it is a selected component which is a function,
1414 -- this is the case of a call to a protected function (which may be
1415 -- overloaded with other protected operations).
1417 or else
1420 or else
1422 E_Entry | E_Procedure
1425 -- If one of the above three conditions is met, rewrite as call. Apply
1426 -- the rewriting only once.
1428 then
1431 then
1433 -- This may be a prefixed call that was not fully analyzed, e.g.
1434 -- an actual in an instance.
1439 then
1447 -- The node is the name of the parameterless call. Preserve its
1448 -- descendants, which may be complex expressions.
1452 -- If overloaded, overload set belongs to new copy
1456 -- Change node to parameterless function call (note that the
1457 -- Parameter_Associations associations field is left set to Empty,
1458 -- its normal default value since there are no parameters)
1478 --------------------------------
1479 -- Is_Atomic_Ref_With_Address --
1480 --------------------------------
1485 begin
1489 else
1490 declare
1493 begin
1501 -----------------------------
1502 -- Is_Definite_Access_Type --
1503 -----------------------------
1507 begin
1513 ----------------------
1514 -- Is_Predefined_Op --
1515 ----------------------
1518 begin
1519 -- Predefined operators are intrinsic subprograms
1525 -- A call to a back-end builtin is never a predefined operator
1536 -----------------------------
1537 -- Make_Call_Into_Operator --
1538 -----------------------------
1540 procedure Make_Call_Into_Operator
1544 is
1559 -- If the operand is not universal, and the operator is given by an
1560 -- expanded name, verify that the operand has an interpretation with a
1561 -- type defined in the given scope of the operator.
1564 -- Find a type of the given class in package Pack that contains the
1565 -- operator.
1567 ---------------------------
1568 -- Operand_Type_In_Scope --
1569 ---------------------------
1576 begin
1580 else
1594 ---------------
1595 -- Type_In_P --
1596 ---------------
1602 -- Verify that node is not part of the type declaration for the
1603 -- candidate type, which would otherwise be invisible.
1605 -------------
1606 -- In_Decl --
1607 -------------
1613 begin
1622 else
1625 loop
1628 else
1637 -- Start of processing for Type_In_P
1639 begin
1640 -- If the context type is declared in the prefix package, this is the
1641 -- desired base type.
1646 else
1660 -- Start of processing for Make_Call_Into_Operator
1662 begin
1665 -- Ensure that the corresponding operator has the same parent as the
1666 -- original call. This guarantees that parent traversals performed by
1667 -- the ABE mechanism succeed.
1671 -- Binary operator
1681 -- Unary operator
1683 else
1689 -- If the operator is denoted by an expanded name, and the prefix is
1690 -- not Standard, but the operator is a predefined one whose scope is
1691 -- Standard, then this is an implicit_operator, inserted as an
1692 -- interpretation by the procedure of the same name. This procedure
1693 -- overestimates the presence of implicit operators, because it does
1694 -- not examine the type of the operands. Verify now that the operand
1695 -- type appears in the given scope. If right operand is universal,
1696 -- check the other operand. In the case of concatenation, either
1697 -- argument can be the component type, so check the type of the result.
1698 -- If both arguments are literals, look for a type of the right kind
1699 -- defined in the given scope. This elaborate nonsense is brought to
1700 -- you courtesy of b33302a. The type itself must be frozen, so we must
1701 -- find the type of the proper class in the given scope.
1703 -- A final wrinkle is the multiplication operator for fixed point types,
1704 -- which is defined in Standard only, and not in the scope of the
1705 -- fixed point type itself.
1710 -- If this is a package renaming, get renamed entity, which will be
1711 -- the scope of the operands if operaton is type-correct.
1717 -- If the entity being called is defined in the given package, it is
1718 -- a renaming of a predefined operator, and known to be legal.
1722 then
1725 -- Visibility does not need to be checked in an instance: if the
1726 -- operator was not visible in the generic it has been diagnosed
1727 -- already, else there is an implicit copy of it in the instance.
1735 then
1740 -- Ada 2005 AI-420: Predefined equality on Universal_Access is
1741 -- available.
1747 then
1750 else
1759 and then Is_Binary
1761 then
1767 -- Verify that the scope contains a type that corresponds to
1768 -- the given literal. Optimize the case where Pack is Standard.
1789 else
1798 else
1807 then
1810 -- If the type is defined elsewhere, and the operator is not
1811 -- defined in the given scope (by a renaming declaration, e.g.)
1812 -- then this is an error as well. If an extension of System is
1813 -- present, and the type may be defined there, Pack must be
1814 -- System itself.
1821 then
1824 else
1830 then
1837 Error_Msg_NE
1842 -- Detect a mismatch between the context type and the result type
1843 -- in the named package, which is otherwise not detected if the
1844 -- operands are universal. Check is only needed if source entity is
1845 -- an operator, not a function that renames an operator.
1852 and then not In_Instance
1853 then
1856 then
1857 -- Already checked above
1861 -- Operator may be defined in an extension of System
1866 then
1869 else
1870 -- Could we use Wrong_Type here??? (this would require setting
1871 -- Etype (N) to the actual type found where Typ was expected).
1882 else
1886 -- If this is a call to a function that renames a predefined equality,
1887 -- the renaming declaration provides a type that must be used to
1888 -- resolve the operands. This must be done now because resolution of
1889 -- the equality node will not resolve any remaining ambiguity, and it
1890 -- assumes that the first operand is not overloaded.
1895 then
1903 -- Do rewrite setting Comes_From_Source on the result if the original
1904 -- call came from source. Although it is not strictly the case that the
1905 -- operator as such comes from the source, logically it corresponds
1906 -- exactly to the function call in the source, so it should be marked
1907 -- this way (e.g. to make sure that validity checks work fine).
1909 declare
1911 begin
1916 -- If this is an arithmetic operator and the result type is private,
1917 -- the operands and the result must be wrapped in conversion to
1918 -- expose the underlying numeric type and expand the proper checks,
1919 -- e.g. on division.
1923 when N_Op_Add
1924 | N_Op_Divide
1925 | N_Op_Expon
1926 | N_Op_Mod
1927 | N_Op_Multiply
1928 | N_Op_Rem
1929 | N_Op_Subtract
1930 =>
1933 when N_Op_Abs
1934 | N_Op_Minus
1935 | N_Op_Plus
1936 =>
1942 else
1947 -------------------
1948 -- Operator_Kind --
1949 -------------------
1951 function Operator_Kind
1954 is
1957 begin
1958 -- Use CASE statement or array???
1995 else
1999 -- Unary operators
2001 else
2010 else
2018 ----------------------------
2019 -- Preanalyze_And_Resolve --
2020 ----------------------------
2022 procedure Preanalyze_And_Resolve
2026 is
2030 Inside_Preanalysis_Without_Freezing;
2031 begin
2036 Inside_Preanalysis_Without_Freezing :=
2043 -- Normally, we suppress all checks for this preanalysis. There is no
2044 -- point in processing them now, since they will be applied properly
2045 -- and in the proper location when the default expressions reanalyzed
2046 -- and reexpanded later on. We will also have more information at that
2047 -- point for possible suppression of individual checks.
2049 -- However, in SPARK mode, most expansion is suppressed, and this
2050 -- later reanalysis and reexpansion may not occur. SPARK mode does
2051 -- require the setting of checking flags for proof purposes, so we
2052 -- do the SPARK preanalysis without suppressing checks.
2054 -- This special handling for SPARK mode is required for example in the
2055 -- case of Ada 2012 constructs such as quantified expressions, which are
2056 -- expanded in two separate steps.
2060 else
2064 Expander_Mode_Restore;
2069 Inside_Preanalysis_Without_Freezing :=
2073 pragma Assert
2077 ----------------------------
2078 -- Preanalyze_And_Resolve --
2079 ----------------------------
2082 begin
2086 -- Version without context type
2091 begin
2098 Expander_Mode_Restore;
2102 ------------------------------------------
2103 -- Preanalyze_With_Freezing_And_Resolve --
2104 ------------------------------------------
2106 procedure Preanalyze_With_Freezing_And_Resolve
2109 is
2110 begin
2114 ----------------------------------
2115 -- Replace_Actual_Discriminants --
2116 ----------------------------------
2123 -- Comment needed???
2125 -------------------
2126 -- Process_Discr --
2127 -------------------
2132 begin
2138 then
2154 -- Start of processing for Replace_Actual_Discriminants
2156 begin
2160 -- Allow the replacement of concurrent discriminants in GNATprove even
2161 -- though this is a light expansion activity. Note that generic units
2162 -- are not modified.
2167 else
2183 -------------
2184 -- Resolve --
2185 -------------
2201 -- Determine whether a node comes from a predefined library unit or
2202 -- Standard.
2205 -- Try and fix up a literal so that it matches its expected type. New
2206 -- literals are manufactured if necessary to avoid cascaded errors.
2209 -- Additional diagnostics when an ambiguous call has an ambiguous
2210 -- argument (typically a controlling actual).
2213 -- Called when attempt at resolving current expression fails
2215 ------------------------------------
2216 -- Comes_From_Predefined_Lib_Unit --
2217 -------------------------------------
2220 begin
2221 return
2225 --------------------
2226 -- Patch_Up_Value --
2227 --------------------
2230 begin
2247 then
2252 Char_Literal_Value =>
2268 -------------------------------
2269 -- Report_Ambiguous_Argument --
2270 -------------------------------
2277 begin
2281 then
2284 -- Examine possible interpretations, and adapt the message
2285 -- for inherited subprograms declared by a type derivation.
2293 else
2301 -- Additional message and hint if the ambiguity involves an Ada 2022
2302 -- container aggregate.
2307 -----------------------
2308 -- Resolution_Failed --
2309 -----------------------
2312 begin
2315 -- Set the type to the desired one to minimize cascaded errors. Note
2316 -- that this is an approximation and does not work in all cases.
2323 -- The caller will return without calling the expander, so we need
2324 -- to set the analyzed flag. Note that it is fine to set Analyzed
2325 -- to True even if we are in the middle of a shallow analysis,
2326 -- (see the spec of sem for more details) since this is an error
2327 -- situation anyway, and there is no point in repeating the
2328 -- analysis later (indeed it won't work to repeat it later, since
2329 -- we haven't got a clear resolution of which entity is being
2330 -- referenced.)
2336 -- Start of processing for Resolve
2338 begin
2343 -- Access attribute on remote subprogram cannot be used for a non-remote
2344 -- access-to-subprogram type.
2348 | Name_Unrestricted_Access
2349 | Name_Unchecked_Access
2355 then
2356 Error_Msg_N
2362 -- If the context is a Remote_Access_To_Subprogram, access attributes
2363 -- must be resolved with the corresponding fat pointer. There is no need
2364 -- to check for the attribute name since the return type of an
2365 -- attribute is never a remote type.
2370 then
2371 declare
2379 begin
2380 -- Check that Typ is a remote access-to-subprogram type
2384 -- Prefix (N) must statically denote a remote subprogram
2385 -- declared in a package specification.
2389 Attr = Attribute_Unrestricted_Access
2390 then
2405 or else
2407 then
2409 Error_Msg_N
2411 N);
2414 -- If we are generating code in distributed mode, perform
2415 -- semantic checks against corresponding remote entities.
2417 if Expander_Active
2419 then
2420 Check_Subtype_Conformant
2422 Old_Id => Designated_Type
2448 then
2453 -- Return if already analyzed
2460 -- Any case of Any_Type as the Etype value means that we had a
2461 -- previous error.
2470 -- The resolution of an Expression_With_Actions is determined by
2471 -- its Expression, but if the node comes from source it is a
2472 -- Declare_Expression and requires scope management.
2477 else
2484 -- If not overloaded, then we know the type, and all that needs doing
2485 -- is to check that this type is compatible with the context.
2491 -- In the overloaded case, we must select the interpretation that
2492 -- is compatible with the context (i.e. the type passed to Resolve)
2494 else
2495 -- Loop through possible interpretations
2504 -- We are only interested in interpretations that are compatible
2505 -- with the expected type, any other interpretations are ignored.
2510 Write_Eol;
2513 else
2514 -- Skip the current interpretation if it is disabled by an
2515 -- abstract operator. This action is performed only when the
2516 -- type against which we are resolving is the same as the
2517 -- type of the interpretation.
2523 then
2531 -- First matching interpretation
2539 -- Matching interpretation that is not the first, maybe an
2540 -- error, but there are some cases where preference rules are
2541 -- used to choose between the two possibilities. These and
2542 -- some more obscure cases are handled in Disambiguate.
2544 else
2545 -- If the current statement is part of a predefined library
2546 -- unit, then all interpretations which come from user level
2547 -- packages should not be considered. Check previous and
2548 -- current one.
2556 -- Previous interpretation must be discarded
2566 -- Otherwise apply further disambiguation steps
2571 -- Disambiguation has succeeded. Skip the remaining
2572 -- interpretations.
2582 else
2583 -- Before we issue an ambiguity complaint, check for the
2584 -- case of a subprogram call where at least one of the
2585 -- arguments is Any_Type, and if so suppress the message,
2586 -- since it is a cascaded error. This can also happen for
2587 -- a generalized indexing operation.
2592 then
2593 declare
2597 begin
2613 Write_Eol;
2626 then
2631 then
2635 -- Not that special case, so issue message using the flag
2636 -- Ambiguous to control printing of the header message
2637 -- only at the start of an ambiguous set.
2642 then
2643 Error_Msg_N
2646 else
2647 Error_Msg_NE -- CODEFIX
2655 Error_Msg_N
2657 else
2658 Error_Msg_N -- CODEFIX
2664 then
2665 Report_Ambiguous_Argument;
2671 -- By default, the error message refers to the candidate
2672 -- interpretation. But if it is a predefined operator, it
2673 -- is implicitly declared at the declaration of the type
2674 -- of the operand. Recover the sloc of that declaration
2675 -- for the error message.
2681 Standard_Standard
2682 then
2687 then
2695 Standard_Standard
2696 then
2701 then
2705 -- If this is an indirect call, use the subprogram_type
2706 -- in the message, to have a meaningful location. Also
2707 -- indicate if this is an inherited operation, created
2708 -- by a type declaration.
2713 then
2715 Error_Msg_Sloc :=
2717 else
2724 then
2725 -- Special-case the message for universal_fixed
2726 -- operators, which are not declared with the type
2727 -- of the operand, but appear forever in Standard.
2731 then
2732 Error_Msg_N
2735 else
2736 Error_Msg_N
2740 elsif
2742 then
2743 Error_Msg_N
2745 else
2746 Error_Msg_N -- CODEFIX
2753 -- We have a matching interpretation, Expr_Type is the type
2754 -- from this interpretation, and Seen is the entity.
2756 -- For an operator, just set the entity name. The type will be
2757 -- set by the specific operator resolution routine.
2764 | N_Character_Literal
2765 | N_Delta_Aggregate
2766 | N_If_Expression
2767 then
2770 -- AI05-0139-2: Expression is overloaded because type has
2771 -- implicit dereference. The context may be the one that
2772 -- requires implicit dereferemce.
2778 -- If the expression is an entity, generate a reference
2779 -- to it, as this is not done for an overloaded construct
2780 -- during analysis.
2784 then
2787 -- Examine access discriminants of entity type,
2788 -- to check whether one of them yields the
2789 -- expected type.
2791 declare
2795 begin
2816 then
2817 -- If the node is a general indexing, the dereference is
2818 -- is inserted when resolving the rewritten form, else
2819 -- insert it now.
2823 then
2827 -- For an explicit dereference, attribute reference, range,
2828 -- short-circuit form (which is not an operator node), or call
2829 -- with a name that is an explicit dereference, there is
2830 -- nothing to be done at this point.
2833 | N_And_Then
2834 | N_Explicit_Dereference
2835 | N_Identifier
2836 | N_Indexed_Component
2837 | N_Or_Else
2838 | N_Range
2839 | N_Selected_Component
2840 | N_Slice
2842 then
2845 -- For procedure or function calls, set the type of the name,
2846 -- and also the entity pointer for the prefix.
2850 then
2857 then
2862 -- For all other cases, just set the type of the Name
2864 else
2872 -- Move to next interpretation
2880 -- At this stage Found indicates whether or not an acceptable
2881 -- interpretation exists. If not, then we have an error, except that if
2882 -- the context is Any_Type as a result of some other error, then we
2883 -- suppress the error report.
2888 -- If type we are looking for is Void, then this is the procedure
2889 -- call case, and the error is simply that what we gave is not a
2890 -- procedure name (we think of procedure calls as expressions with
2891 -- types internally, but the user doesn't think of them this way).
2895 -- Special case message if function used as a procedure
2900 then
2901 Error_Msg_NE
2904 Error_Msg_N
2908 -- Otherwise give general message (not clear what cases this
2909 -- covers, but no harm in providing for them).
2911 else
2917 -- Otherwise we do have a subexpression with the wrong type
2919 -- Check for the case of an allocator which uses an access type
2920 -- instead of the designated type. This is a common error and we
2921 -- specialize the message, posting an error on the operand of the
2922 -- allocator, complaining that we expected the designated type of
2923 -- the allocator.
2929 then
2933 -- Check for view mismatch on Null in instances, for which the
2934 -- view-swapping mechanism has no identifier.
2940 then
2945 -- Check for an aggregate. Sometimes we can get bogus aggregates
2946 -- from misuse of parentheses, and we are about to complain about
2947 -- the aggregate without even looking inside it.
2949 -- Instead, if we have an aggregate of type Any_Composite, then
2950 -- analyze and resolve the component fields, and then only issue
2951 -- another message if we get no errors doing this (otherwise
2952 -- assume that the errors in the aggregate caused the problem).
2956 then
2959 then
2968 -- Disable expansion in any case. If there is a type mismatch
2969 -- it may be fatal to try to expand the aggregate. The flag
2970 -- would otherwise be set to false when the error is posted.
2974 declare
2976 -- Check one aggregate, and set Found to True if we have a
2977 -- definite error in any of its elements
2980 -- Check one element of aggregate and set Found to True if
2981 -- we definitely have an error in the element.
2983 ----------------
2984 -- Check_Aggr --
2985 ----------------
2990 begin
3003 -- If this is a default-initialized component, then
3004 -- there is nothing to check. The box will be
3005 -- replaced by the appropriate call during late
3006 -- expansion.
3010 then
3019 ----------------
3020 -- Check_Elmt --
3021 ----------------
3024 begin
3025 -- If we have a nested aggregate, go inside it (to
3026 -- attempt a naked analyze-resolve of the aggregate can
3027 -- cause undesirable cascaded errors). Do not resolve
3028 -- expression if it needs a type from context, as for
3029 -- integer * fixed expression.
3034 else
3039 then
3049 begin
3054 -- If node is a literal and context type has a user-defined
3055 -- literal aspect, rewrite node as a call to the corresponding
3056 -- function, which plays the role of an implicit conversion.
3059 N_Numeric_Or_String_Literal | N_Identifier
3061 then
3066 -- Looks like we have a type error, but check for special case
3067 -- of Address wanted, integer found, with the configuration pragma
3068 -- Allow_Integer_Address active. If we have this case, introduce
3069 -- an unchecked conversion to allow the integer expression to be
3070 -- treated as an Address. The reverse case of integer wanted,
3071 -- Address found, is treated in an analogous manner.
3078 -- Under relaxed RM semantics silently replace occurrences of null
3079 -- by System.Null_Address.
3087 -- That special Allow_Integer_Address check did not apply, so we
3088 -- have a real type error. If an error message was issued already,
3089 -- Found got reset to True, so if it's still False, issue standard
3090 -- Wrong_Type message.
3094 declare
3097 begin
3103 -- Protected operation: retrieve operation name
3107 else
3112 Error_Msg_NE
3118 declare
3122 begin
3129 Error_Msg_NE
3135 else
3139 -- Recognize the case of a quantified expression being mistaken
3140 -- for an iterated component association because the user
3141 -- forgot the "all" or "some" keyword after "for". Because the
3142 -- error message starts with "missing ALL", we automatically
3143 -- benefit from the associated CODEFIX, which requires that
3144 -- the message is located on the identifier following "for"
3145 -- in order for the CODEFIX to insert "all" in the right place.
3150 = N_Iterated_Component_Association
3152 then
3153 Error_Msg_N -- CODEFIX
3157 -- For an operator with no interpretation, check whether
3158 -- one of its operands may be a user-defined literal.
3162 then
3165 else
3171 Resolution_Failed;
3174 -- Test if we have more than one interpretation for the context
3177 Resolution_Failed;
3180 -- Only one interpretation
3182 else
3183 -- Prevent implicit conversions between access-to-subprogram types
3184 -- with different strub modes. Explicit conversions are acceptable in
3185 -- some circumstances. We don't have to be concerned about data or
3186 -- access-to-data types. Conversions between data types can safely
3187 -- drop or add strub attributes from types, because strub effects are
3188 -- associated with the locations rather than values. E.g., converting
3189 -- a hypothetical Strub_Integer variable to Integer would load the
3190 -- value from the variable, enabling stack scrabbing for the
3191 -- enclosing subprogram, and then convert the value to Integer. As
3192 -- for conversions between access-to-data types, that's no different
3193 -- from any other case of type punning.
3199 then
3200 Check_Same_Strub_Mode
3204 -- In Ada 2005, if we have something like "X : T := 2 + 2;", where
3205 -- the "+" on T is abstract, and the operands are of universal type,
3206 -- the above code will have (incorrectly) resolved the "+" to the
3207 -- universal one in Standard. Therefore check for this case and give
3208 -- an error. We can't do this earlier, because it would cause legal
3209 -- cases to get errors (when some other type has an abstract "+").
3215 then
3220 then
3221 Error_Msg_NE
3230 -- Here we have an acceptable interpretation for the context
3232 -- Propagate type information and normalize tree for various
3233 -- predefined operations. If the context only imposes a class of
3234 -- types, rather than a specific type, propagate the actual type
3235 -- downward.
3241 Typ = Any_Discrete
3242 then
3245 -- Any_Fixed is legal in a real context only if a specific fixed-
3246 -- point type is imposed. If Norman Cohen can be confused by this,
3247 -- it deserves a separate message.
3251 then
3258 -- A user-defined operator is transformed into a function call at
3259 -- this point, so that further processing knows that operators are
3260 -- really operators (i.e. are predefined operators). User-defined
3261 -- operators that are intrinsic are just renamings of the predefined
3262 -- ones, and need not be turned into calls either, but if they rename
3263 -- a different operator, we must transform the node accordingly.
3264 -- Instantiations of Unchecked_Conversion are intrinsic but are
3265 -- treated as functions, even if given an operator designator.
3270 then
3275 and then
3277 N_Subprogram_Renaming_Declaration
3278 then
3281 -- If the node is rewritten, it will be fully resolved in
3282 -- Rewrite_Renamed_Operator.
3291 when N_Aggregate =>
3292 Resolve_Aggregate (N, Ctx_Type);
3294 when N_Allocator =>
3295 Resolve_Allocator (N, Ctx_Type);
3297 when N_Short_Circuit =>
3298 Resolve_Short_Circuit (N, Ctx_Type);
3300 when N_Attribute_Reference =>
3301 Resolve_Attribute (N, Ctx_Type);
3303 when N_Case_Expression =>
3304 Resolve_Case_Expression (N, Ctx_Type);
3306 when N_Character_Literal =>
3307 Resolve_Character_Literal (N, Ctx_Type);
3309 when N_Delta_Aggregate =>
3310 Resolve_Delta_Aggregate (N, Ctx_Type);
3312 when N_Expanded_Name =>
3313 Resolve_Entity_Name (N, Ctx_Type);
3315 when N_Explicit_Dereference =>
3316 Resolve_Explicit_Dereference (N, Ctx_Type);
3318 when N_Expression_With_Actions =>
3319 Resolve_Expression_With_Actions (N, Ctx_Type);
3321 when N_Extension_Aggregate =>
3322 Resolve_Extension_Aggregate (N, Ctx_Type);
3324 when N_Function_Call =>
3325 Resolve_Call (N, Ctx_Type);
3327 when N_Identifier =>
3328 Resolve_Entity_Name (N, Ctx_Type);
3330 when N_If_Expression =>
3331 Resolve_If_Expression (N, Ctx_Type);
3333 when N_Indexed_Component =>
3334 Resolve_Indexed_Component (N, Ctx_Type);
3336 when N_Integer_Literal =>
3337 Resolve_Integer_Literal (N, Ctx_Type);
3339 when N_Membership_Test =>
3340 Resolve_Membership_Op (N, Ctx_Type);
3342 when N_Null =>
3343 Resolve_Null (N, Ctx_Type);
3345 when N_Op_And
3346 | N_Op_Or
3347 | N_Op_Xor
3348 =>
3349 Resolve_Logical_Op (N, Ctx_Type);
3351 when N_Op_Eq
3352 | N_Op_Ne
3353 =>
3354 Resolve_Equality_Op (N, Ctx_Type);
3356 when N_Op_Ge
3357 | N_Op_Gt
3358 | N_Op_Le
3359 | N_Op_Lt
3360 =>
3361 Resolve_Comparison_Op (N, Ctx_Type);
3363 when N_Op_Not =>
3364 Resolve_Op_Not (N, Ctx_Type);
3366 when N_Op_Add
3367 | N_Op_Divide
3368 | N_Op_Mod
3369 | N_Op_Multiply
3370 | N_Op_Rem
3371 | N_Op_Subtract
3372 =>
3373 Resolve_Arithmetic_Op (N, Ctx_Type);
3375 when N_Op_Concat =>
3376 Resolve_Op_Concat (N, Ctx_Type);
3378 when N_Op_Expon =>
3379 Resolve_Op_Expon (N, Ctx_Type);
3381 when N_Op_Abs
3382 | N_Op_Minus
3383 | N_Op_Plus
3384 =>
3385 Resolve_Unary_Op (N, Ctx_Type);
3387 when N_Op_Shift =>
3388 Resolve_Shift (N, Ctx_Type);
3390 when N_Procedure_Call_Statement =>
3391 Resolve_Call (N, Ctx_Type);
3393 when N_Operator_Symbol =>
3394 Resolve_Operator_Symbol (N, Ctx_Type);
3396 when N_Qualified_Expression =>
3397 Resolve_Qualified_Expression (N, Ctx_Type);
3399 -- Why is the following null, needs a comment ???
3401 when N_Quantified_Expression =>
3402 null;
3404 when N_Raise_Expression =>
3405 Resolve_Raise_Expression (N, Ctx_Type);
3407 when N_Raise_xxx_Error =>
3408 Set_Etype (N, Ctx_Type);
3410 when N_Range =>
3411 Resolve_Range (N, Ctx_Type);
3413 when N_Real_Literal =>
3414 Resolve_Real_Literal (N, Ctx_Type);
3416 when N_Reference =>
3417 Resolve_Reference (N, Ctx_Type);
3419 when N_Selected_Component =>
3420 Resolve_Selected_Component (N, Ctx_Type);
3422 when N_Slice =>
3423 Resolve_Slice (N, Ctx_Type);
3425 when N_String_Literal =>
3426 Resolve_String_Literal (N, Ctx_Type);
3428 when N_Target_Name =>
3429 Resolve_Target_Name (N, Ctx_Type);
3431 when N_Type_Conversion =>
3432 Resolve_Type_Conversion (N, Ctx_Type);
3434 when N_Unchecked_Expression =>
3435 Resolve_Unchecked_Expression (N, Ctx_Type);
3437 when N_Unchecked_Type_Conversion =>
3438 Resolve_Unchecked_Type_Conversion (N, Ctx_Type);
3439 end case;
3441 -- Mark relevant use-type and use-package clauses as effective using
3442 -- the original node because constant folding may have occured and
3443 -- removed references that need to be examined.
3445 if Nkind (Original_Node (N)) in N_Op then
3446 Mark_Use_Clauses (Original_Node (N));
3447 end if;
3449 -- Ada 2012 (AI05-0149): Apply an (implicit) conversion to an
3450 -- expression of an anonymous access type that occurs in the context
3451 -- of a named general access type, except when the expression is that
3452 -- of a membership test. This ensures proper legality checking in
3453 -- terms of allowed conversions (expressions that would be illegal to
3454 -- convert implicitly are allowed in membership tests).
3456 if Ada_Version >= Ada_2012
3457 and then Ekind (Base_Type (Ctx_Type)) = E_General_Access_Type
3458 and then Ekind (Etype (N)) = E_Anonymous_Access_Type
3459 and then Nkind (Parent (N)) not in N_Membership_Test
3460 then
3461 Rewrite (N, Convert_To (Ctx_Type, Relocate_Node (N)));
3462 Analyze_And_Resolve (N, Ctx_Type);
3463 end if;
3465 -- If the subexpression was replaced by a non-subexpression, then
3466 -- all we do is to expand it. The only legitimate case we know of
3467 -- is converting procedure call statement to entry call statements,
3468 -- but there may be others, so we are making this test general.
3470 if Nkind (N) not in N_Subexpr then
3471 Debug_A_Exit ("resolving ", N, " (done)");
3472 Expand (N);
3473 return;
3474 end if;
3476 -- The expression is definitely NOT overloaded at this point, so
3477 -- we reset the Is_Overloaded flag to avoid any confusion when
3478 -- reanalyzing the node.
3480 Set_Is_Overloaded (N, False);
3482 -- Freeze expression type, entity if it is a name, and designated
3483 -- type if it is an allocator (RM 13.14(10,11,13)).
3485 -- Now that the resolution of the type of the node is complete, and
3486 -- we did not detect an error, we can expand this node. We skip the
3487 -- expand call if we are in a default expression, see section
3488 -- "Handling of Default Expressions" in Sem spec.
3490 Debug_A_Exit ("resolving ", N, " (done)");
3492 -- We unconditionally freeze the expression, even if we are in
3493 -- default expression mode (the Freeze_Expression routine tests this
3494 -- flag and only freezes static types if it is set).
3496 -- Ada 2012 (AI05-177): The declaration of an expression function
3497 -- does not cause freezing, but we never reach here in that case.
3498 -- Here we are resolving the corresponding expanded body, so we do
3499 -- need to perform normal freezing.
3501 -- As elsewhere we do not emit freeze node within a generic.
3503 if not Inside_A_Generic then
3504 Freeze_Expression (N);
3505 end if;
3507 -- Now we can do the expansion
3509 Expand (N);
3510 end if;
3511 end Resolve;
3513 -------------
3514 -- Resolve --
3515 -------------
3517 -- Version with check(s) suppressed
3519 procedure Resolve (N : Node_Id; Typ : Entity_Id; Suppress : Check_Id) is
3520 begin
3521 if Suppress = All_Checks then
3522 declare
3523 Sva : constant Suppress_Array := Scope_Suppress.Suppress;
3524 begin
3525 Scope_Suppress.Suppress := (others => True);
3526 Resolve (N, Typ);
3527 Scope_Suppress.Suppress := Sva;
3528 end;
3530 else
3531 declare
3532 Svg : constant Boolean := Scope_Suppress.Suppress (Suppress);
3533 begin
3534 Scope_Suppress.Suppress (Suppress) := True;
3535 Resolve (N, Typ);
3536 Scope_Suppress.Suppress (Suppress) := Svg;
3537 end;
3538 end if;
3539 end Resolve;
3541 -------------
3542 -- Resolve --
3543 -------------
3545 -- Version with implicit type
3547 procedure Resolve (N : Node_Id) is
3548 begin
3549 Resolve (N, Etype (N));
3550 end Resolve;
3552 ---------------------
3553 -- Resolve_Actuals --
3554 ---------------------
3556 procedure Resolve_Actuals (N : Node_Id; Nam : Entity_Id) is
3557 Loc : constant Source_Ptr := Sloc (N);
3558 A : Node_Id;
3559 A_Typ : Entity_Id := Empty; -- init to avoid warning
3560 F : Entity_Id;
3561 F_Typ : Entity_Id;
3562 Prev : Node_Id := Empty;
3563 Orig_A : Node_Id;
3564 Real_F : Entity_Id := Empty; -- init to avoid warning
3566 Real_Subp : Entity_Id;
3567 -- If the subprogram being called is an inherited operation for
3568 -- a formal derived type in an instance, Real_Subp is the subprogram
3569 -- that will be called. It may have different formal names than the
3570 -- operation of the formal in the generic, so after actual is resolved
3571 -- the name of the actual in a named association must carry the name
3572 -- of the actual of the subprogram being called.
3574 procedure Check_Aliased_Parameter;
3575 -- Check rules on aliased parameters and related accessibility rules
3576 -- in (RM 3.10.2 (10.2-10.4)).
3578 procedure Check_Argument_Order;
3579 -- Performs a check for the case where the actuals are all simple
3580 -- identifiers that correspond to the formal names, but in the wrong
3581 -- order, which is considered suspicious and cause for a warning.
3583 procedure Check_Prefixed_Call;
3584 -- If the original node is an overloaded call in prefix notation,
3586 -- Try_Object_Operation has already verified that there is a valid
3587 -- interpretation, but the form of the actual can only be determined
3588 -- once the primitive operation is identified.
3591 -- Emit an error concerning the illegal usage of an effectively volatile
3592 -- object for reading in interfering context (SPARK RM 7.1.3(10)).
3595 -- If the actual is missing in a call, insert in the actuals list
3596 -- an instance of the default expression. The insertion is always
3597 -- a named association.
3600 -- Check whether T1 and T2, or their full views, are derived from a
3601 -- common type. Used to enforce the restrictions on array conversions
3602 -- of AI95-00246.
3605 -- Predicate to determine whether an actual that is a concatenation
3606 -- will be evaluated statically and does not need a transient scope.
3607 -- This must be determined before the actual is resolved and expanded
3608 -- because if needed the transient scope must be introduced earlier.
3610 -----------------------------
3611 -- Check_Aliased_Parameter --
3612 -----------------------------
3617 begin
3625 else
3632 -- In a generic body assume the worst for generic formals:
3633 -- they can have a constrained partial view (AI05-041).
3637 and then not Object_Type_Has_Constrained_Partial_View
3639 then
3642 else
3647 else
3659 then
3667 then
3668 Error_Msg_N
3674 --------------------------
3675 -- Check_Argument_Order --
3676 --------------------------
3679 begin
3680 -- Nothing to do if no parameters, or original node is neither a
3681 -- function call nor a procedure call statement (happens in the
3682 -- operator-transformed-to-function call case), or the call is to an
3683 -- operator symbol (which is usually in infix form), or the call does
3684 -- not come from source, or this warning is off.
3686 if not Warn_On_Parameter_Order
3692 N_Defining_Operator_Symbol)
3694 then
3698 declare
3701 begin
3702 -- Nothing to do if only one parameter
3708 -- Here if at least two arguments
3710 declare
3716 -- Set True if an out of order case is found
3718 begin
3719 -- Collect identifier names of actuals, fail if any actual is
3720 -- not a simple identifier, and record max length of name.
3726 else
3732 -- If we got this far, all actuals are identifiers and the list
3733 -- of their names is stored in the Actuals array.
3738 -- If we ran out of formals, that's odd, probably an error
3739 -- which will be detected elsewhere, but abandon the search.
3745 -- If name matches and is in order OK
3750 else
3751 -- If no match, see if it is elsewhere in list and if so
3752 -- flag potential wrong order if type is compatible.
3756 and then
3758 then
3764 -- No match
3772 -- If Formals left over, also probably an error, skip warning
3778 -- Here we give the warning if something was out of order
3781 Error_Msg_N
3788 -------------------------
3789 -- Check_Prefixed_Call --
3790 -------------------------
3799 begin
3800 -- Check whether the call is a prefixed call, with or without
3801 -- additional actuals.
3804 or else
3810 then
3813 then
3814 -- Introduce dereference on object in prefix
3816 New_A :=
3824 then
3825 -- Introduce an implicit 'Access in prefix
3828 Error_Msg_NE
3844 ---------------------------------------
3845 -- Flag_Effectively_Volatile_Objects --
3846 ---------------------------------------
3850 -- Determine whether arbitrary node N denotes an effectively volatile
3851 -- object for reading and if it does, emit an error.
3853 -----------------
3854 -- Flag_Object --
3855 -----------------
3860 begin
3862 -- Do not consider nested function calls because they have
3863 -- already been processed during their own resolution.
3874 and then
3878 then
3879 Error_Msg_N
3893 -- Start of processing for Flag_Effectively_Volatile_Objects
3895 begin
3899 --------------------
3900 -- Insert_Default --
3901 --------------------
3907 begin
3908 -- Missing argument in call, nothing to insert
3913 else
3914 -- Note that we do a full New_Copy_Tree, so that any associated
3915 -- Itypes are properly copied. This may not be needed any more,
3916 -- but it does no harm as a safety measure. Defaults of a generic
3917 -- formal may be out of bounds of the corresponding actual (see
3918 -- cc1311b) and an additional check may be required.
3920 Actval :=
3921 New_Copy_Tree
3926 -- Propagate dimension information, if any.
3932 then
3938 then
3941 then
3942 -- If default is a real literal, do not introduce a
3943 -- conversion whose effect may depend on the run-time
3944 -- size of universal real.
3948 else
3959 -- Resolve aggregates with their base type, to avoid scope
3960 -- anomalies: the subtype was first built in the subprogram
3961 -- declaration, and the current call may be nested.
3965 else
3969 else
3972 -- See note above concerning aggregates
3976 then
3979 -- Resolve entities with their own type, which may differ from
3980 -- the type of a reference in a generic context (the view
3981 -- swapping mechanism did not anticipate the re-analysis of
3982 -- default values in calls).
3987 else
3992 -- If default is a tag indeterminate function call, propagate tag
3993 -- to obtain proper dispatching.
3997 then
4002 -- If the default expression raises constraint error, then just
4003 -- silently replace it with an N_Raise_Constraint_Error node, since
4004 -- we already gave the warning on the subprogram spec. If node is
4005 -- already a Raise_Constraint_Error leave as is, to prevent loops in
4006 -- the warnings removal machinery.
4010 then
4019 Assoc :=
4024 -- Case of insertion is first named actual
4028 then
4035 else
4039 else
4043 -- Case of insertion is not first named actual
4045 else
4046 Set_Next_Named_Actual
4058 -------------------
4059 -- Same_Ancestor --
4060 -------------------
4066 begin
4069 then
4075 then
4082 --------------------------
4083 -- Static_Concatenation --
4084 --------------------------
4087 begin
4094 -- Concatenation is static when both operands are static and
4095 -- the concatenation operator is a predefined one.
4098 and then
4100 and then
4105 declare
4107 begin
4110 and then
4114 else
4120 -- Start of processing for Resolve_Actuals
4122 begin
4123 Check_Argument_Order;
4127 and then In_Instance
4130 then
4132 else
4137 Check_Prefixed_Call;
4151 -- If we have an error in any actual or formal, indicated by a type
4152 -- of Any_Type, then abandon resolution attempt, and set result type
4153 -- to Any_Type. Skip this if the actual is a Raise_Expression, whose
4154 -- type is imposed from context.
4158 then
4165 -- Case where actual is present
4167 -- If the actual is an entity, generate a reference to it now. We
4168 -- do this before the actual is resolved, because a formal of some
4169 -- protected subprogram, or a task discriminant, will be rewritten
4170 -- during expansion, and the source entity reference may be lost.
4175 then
4176 -- Annotate the tree by creating a variable reference marker when
4177 -- the actual denotes a variable reference, in case the reference
4178 -- is folded or optimized away. The variable reference marker is
4179 -- automatically saved for later examination by the ABE Processing
4180 -- phase. The status of the reference is set as follows:
4182 -- status mode
4183 -- read IN, IN OUT
4184 -- write IN OUT, OUT
4186 if Needs_Variable_Reference_Marker
4189 then
4190 Build_Variable_Reference_Marker
4201 then
4208 -- RM 6.4.1(12): For an out parameter that is passed by
4209 -- copy, the formal parameter object is created, and:
4211 -- * For an access type, the formal parameter is initialized
4212 -- from the value of the actual, without checking that the
4213 -- value satisfies any constraint, any predicate, or any
4214 -- exclusion of the null value.
4216 -- * For a scalar type that has the Default_Value aspect
4217 -- specified, the formal parameter is initialized from the
4218 -- value of the actual, without checking that the value
4219 -- satisfies any constraint or any predicate.
4220 -- I do not understand why this case is included??? this is
4221 -- not a case where an OUT parameter is treated as IN OUT.
4223 -- * For a composite type with discriminants or that has
4224 -- implicit initial values for any subcomponents, the
4225 -- behavior is as for an in out parameter passed by copy.
4227 -- Hence for these cases we generate the read reference now
4228 -- (the write reference will be generated later by
4229 -- Note_Possible_Modification).
4232 and then
4234 or else
4236 and then
4238 or else
4241 or else Is_Partially_Initialized_Type
4243 then
4253 then
4254 -- If style checking mode on, check match of formal name
4262 -- If the formal is Out or In_Out, do not resolve and expand the
4263 -- conversion, because it is subsequently expanded into explicit
4264 -- temporaries and assignments. However, the object of the
4265 -- conversion can be resolved. An exception is the case of tagged
4266 -- type conversion with a class-wide actual. In that case we want
4267 -- the tag check to occur and no temporary will be needed (no
4268 -- representation change can occur) and the parameter is passed by
4269 -- reference, so we go ahead and resolve the type conversion.
4270 -- Another exception is the case of reference to component or
4271 -- subcomponent of a bit-packed array, in which case we want to
4272 -- defer expansion to the point the in and out assignments are
4273 -- performed.
4279 then
4280 declare
4283 begin
4284 -- Check RM 4.6 (24.2/2)
4288 then
4289 -- In a view conversion, the conversion must be legal in
4290 -- both directions, and thus both component types must be
4291 -- aliased, or neither (4.6 (8)).
4293 -- Check RM 4.6 (24.8/2)
4297 then
4298 -- This normally illegal conversion is legal in an
4299 -- expanded instance body because of RM 12.3(11).
4300 -- At runtime, conversion must create a new object.
4303 Error_Msg_N
4308 -- Check RM 4.6 (24/3)
4311 -- Check view conv between unrelated by ref array
4312 -- types.
4316 then
4317 Error_Msg_N
4321 -- In Ada 2005 mode, check view conversion component
4322 -- type cannot be private, tagged, or volatile. Note
4323 -- that we only apply this to source conversions. The
4324 -- generated code can contain conversions which are
4325 -- not subject to this test, and we cannot extract the
4326 -- component type in such cases since it is not
4327 -- present.
4331 then
4332 declare
4335 begin
4340 then
4341 Error_Msg_N
4351 -- AI12-0074 & AI12-0377
4352 -- Check 6.4.1: If the mode is out, the actual parameter is
4353 -- a view conversion, and the type of the formal parameter
4354 -- is a scalar type, then either:
4355 -- - the target and operand type both do not have the
4356 -- Default_Value aspect specified; or
4357 -- - the target and operand type both have the
4358 -- Default_Value aspect specified, and there shall exist
4359 -- a type (other than a root numeric type) that is an
4360 -- ancestor of both the target type and the operand
4361 -- type.
4365 then
4368 then
4369 Error_Msg_N
4374 then
4375 Error_Msg_N
4382 -- Resolve expression if conversion is all OK
4387 then
4391 -- If the actual is a function call that returns a limited
4392 -- unconstrained object that needs finalization, create a
4393 -- transient scope for it, so that it can receive the proper
4394 -- finalization list.
4396 elsif Expander_Active
4402 then
4406 -- A small optimization: if one of the actuals is a concatenation
4407 -- create a block around a procedure call to recover stack space.
4408 -- This alleviates stack usage when several procedure calls in
4409 -- the same statement list use concatenation. We do not perform
4410 -- this wrapping for code statements, where the argument is a
4411 -- static string, and we want to preserve warnings involving
4412 -- sequences of such statements.
4414 elsif Expander_Active
4420 then
4424 else
4428 and then
4431 then
4432 Error_Msg_N
4445 -- (Ada 2005: AI-251): If the actual is an allocator whose
4446 -- directly designated type is a class-wide interface, we build
4447 -- an anonymous access type to use it as the type of the
4448 -- allocator. Later, when the subprogram call is expanded, if
4449 -- the interface has a secondary dispatch table the expander
4450 -- will add a type conversion to force the correct displacement
4451 -- of the pointer.
4454 declare
4458 begin
4459 -- Displace the pointer to the object to reference its
4460 -- secondary dispatch table.
4464 then
4470 -- Ada 2005, AI-162:If the actual is an allocator, the
4471 -- innermost enclosing statement is the master of the
4472 -- created object. This needs to be done with expansion
4473 -- enabled only, otherwise the transient scope will not
4474 -- be removed in the expansion of the wrapped construct.
4476 if Expander_Active
4479 then
4480 Establish_Transient_Scope
4490 -- (Ada 2005): The call may be to a primitive operation of a
4491 -- tagged synchronized type, declared outside of the type. In
4492 -- this case the controlling actual must be converted to its
4493 -- corresponding record type, which is the formal type. The
4494 -- actual may be a subtype, either because of a constraint or
4495 -- because it is a generic actual, so use base type to locate
4496 -- concurrent type.
4503 then
4504 -- If the actual is overloaded, look for an interpretation
4505 -- that has a synchronized type.
4510 else
4511 declare
4515 begin
4520 then
4530 declare
4533 begin
4536 else
4540 -- Tagged synchronized type (case 1): the actual is a
4541 -- concurrent type.
4545 then
4547 Unchecked_Convert_To
4551 -- Tagged synchronized type (case 2): the formal is a
4552 -- concurrent type.
4555 and then Present
4560 then
4563 -- Common case
4565 else
4570 -- Not a synchronized operation
4572 else
4580 -- An actual cannot be an untagged formal incomplete type
4585 then
4586 Error_Msg_N
4590 -- has warnings suppressed, then we reset Never_Set_In_Source for
4591 -- the calling entity. The reason for this is to catch cases like
4592 -- GNAT.Spitbol.Patterns.Vstring_Var where the called subprogram
4593 -- uses trickery to modify an IN parameter.
4600 then
4604 -- Perform error checks for IN and IN OUT parameters
4608 -- Check unset reference. For scalar parameters, it is clearly
4609 -- wrong to pass an uninitialized value as either an IN or
4610 -- IN-OUT parameter. For composites, it is also clearly an
4611 -- error to pass a completely uninitialized value as an IN
4612 -- parameter, but the case of IN OUT is trickier. We prefer
4613 -- not to give a warning here. For example, suppose there is
4614 -- a routine that sets some component of a record to False.
4615 -- It is perfectly reasonable to make this IN-OUT and allow
4616 -- either initialized or uninitialized records to be passed
4617 -- in this case.
4619 -- For partially initialized composite values, we also avoid
4620 -- warnings, since it is quite likely that we are passing a
4621 -- partially initialized value and only the initialized fields
4622 -- will in fact be read in the subprogram.
4627 then
4631 -- In Ada 83 we cannot pass an OUT parameter as an IN or IN OUT
4632 -- actual to a nested call, since this constitutes a reading of
4633 -- the parameter, which is not allowed.
4638 then
4643 -- In -gnatd.q mode, forget that a given array is constant when
4644 -- it is passed as an IN parameter to a foreign-convention
4645 -- subprogram. This is in case the subprogram evilly modifies the
4646 -- object. Of course, correct code would use IN OUT.
4648 if Debug_Flag_Dot_Q
4654 then
4658 -- Case of OUT or IN OUT parameter
4662 -- For an Out parameter, check for useless assignment. Note
4663 -- that we can't set Last_Assignment this early, because we may
4664 -- kill current values in Resolve_Call, and that call would
4665 -- clobber the Last_Assignment field.
4667 -- Note: call Warn_On_Useless_Assignment before doing the check
4668 -- below for Is_OK_Variable_For_Out_Formal so that the setting
4669 -- of Referenced_As_LHS/Referenced_As_Out_Formal properly
4670 -- reflects the last assignment, not this one.
4677 then
4682 -- Validate the form of the actual. Note that the call to
4683 -- Is_OK_Variable_For_Out_Formal generates the required
4684 -- reference in this case.
4686 -- A call to an initialization procedure for an aggregate
4687 -- component may initialize a nested component of a constant
4688 -- designated object. In this context the object is variable.
4692 then
4698 then
4699 Error_Msg_N
4704 Error_Msg_N
4711 -- What's the following about???
4715 else
4716 Kill_All_Checks;
4725 -- Apply appropriate constraint/predicate checks for IN [OUT] case
4729 -- Apply predicate tests except in certain special cases. Note
4730 -- that it might be more consistent to apply these only when
4731 -- expansion is active (in Exp_Ch6.Expand_Actuals), as we do
4732 -- for the outbound predicate tests ??? In any case indicate
4733 -- the function being called, for better warnings if the call
4734 -- leads to an infinite recursion.
4740 -- Apply required constraint checks
4753 then
4756 -- For view conversions of a discriminated object, apply
4757 -- check to object itself, the conversion alreay has the
4758 -- proper type.
4762 then
4769 then
4775 then
4778 else
4782 -- Ada 2005 (AI-231): Note that the controlling parameter case
4783 -- already existed in Ada 95, which is partially checked
4784 -- elsewhere (see Checks), and we don't want the warning
4785 -- message to differ.
4790 then
4792 Apply_Compile_Time_Constraint_Error
4798 Apply_Compile_Time_Constraint_Error
4807 -- Checks for OUT parameters and IN OUT parameters
4811 -- If there is a type conversion, make sure the return value
4812 -- meets the constraints of the variable before the conversion.
4817 -- Special case here tailored to Exp_Ch6.Is_Legal_Copy,
4818 -- which would prevent the check from being generated.
4819 -- This is for Starlet only though, so long obsolete.
4824 then
4826 else
4827 Apply_Scalar_Range_Check
4831 -- In addition the return value must meet the constraints
4832 -- of the object type (see the comment below).
4836 else
4837 Apply_Range_Check
4841 -- If no conversion, apply scalar range checks and length check
4842 -- based on the subtype of the actual (NOT that of the formal).
4843 -- This indicates that the check takes place on return from the
4844 -- call. During expansion the required constraint checks are
4845 -- inserted. In GNATprove mode, in the absence of expansion,
4846 -- the flag indicates that the returned value is valid.
4848 else
4854 then
4857 else
4862 -- Note: we do not apply the predicate checks for the case of
4863 -- OUT and IN OUT parameters. They are instead applied in the
4864 -- Expand_Actuals routine in Exp_Ch6.
4867 -- If the formal is of an unconstrained array subtype with fixed
4868 -- lower bound, then sliding to that bound may be needed.
4874 -- An actual associated with an access parameter is implicitly
4875 -- converted to the anonymous access type of the formal and must
4876 -- satisfy the legality checks for access conversions.
4880 Error_Msg_N
4884 -- If the actual is an access selected component of a variable,
4885 -- the call may modify its designated object. It is reasonable
4886 -- to treat this as a potential modification of the enclosing
4887 -- record, to prevent spurious warnings that it should be
4888 -- declared as a constant, because intuitively programmers
4889 -- regard the designated subcomponent as part of the record.
4894 then
4899 -- Check illegal cases of atomic/volatile/VFA actual (RM C.6(12))
4903 then
4906 then
4907 Error_Msg_NE
4910 Error_Msg_N
4915 then
4916 Error_Msg_NE
4919 Error_Msg_N
4924 then
4925 Error_Msg_NE
4928 Error_Msg_N
4932 -- Check for nonatomic subcomponent of a full access object
4933 -- in Ada 2022 (RM C.6 (12)).
4938 then
4939 Error_Msg_N
4942 Error_Msg_NE
4948 -- Check that subprograms don't have improper controlling
4949 -- arguments (RM 3.9.2 (9)).
4951 -- A primitive operation may have an access parameter of an
4952 -- incomplete tagged type, but a dispatching call is illegal
4953 -- if the type is still incomplete.
4959 declare
4961 begin
4965 then
4966 Error_Msg_NE
4977 -- Apply legality rule 3.9.2 (9/1)
4979 -- Skip this check on helpers and indirect-call wrappers built to
4980 -- support class-wide preconditions.
4985 and then not In_Instance
4988 then
4993 Error_Msg_NE
4997 -- Apply the checks described in 3.10.2(27): if the context is a
4998 -- specific access-to-object, the actual cannot be class-wide.
4999 -- Use base type to exclude access_to_subprogram cases.
5006 and then
5011 -- Disable these checks for call to imported C++ subprograms
5013 and then not
5017 then
5018 Error_Msg_N
5023 Error_Msg_NE
5028 Check_Aliased_Parameter;
5032 -- If it is a named association, treat the selector_name as a
5033 -- proper identifier, and mark the corresponding entity.
5037 -- Ignore reference in SPARK mode, as it refers to an entity not
5038 -- in scope at the point of reference, so the reference should
5039 -- be ignored for computing effects of subprograms.
5041 and then not GNATprove_Mode
5042 then
5043 -- If subprogram is overridden, use name of formal that
5044 -- is being called.
5050 else
5064 -- The following checks are only relevant when SPARK_Mode is on as
5065 -- they are not standard Ada legality rule. Internally generated
5066 -- temporaries are ignored.
5070 -- Inspect the expression and flag each effectively volatile
5071 -- object for reading as illegal because it appears within
5072 -- an interfering context. Note that this is usually done
5073 -- in Resolve_Entity_Name, but when the effectively volatile
5074 -- object for reading appears as an actual in a call, the call
5075 -- must be resolved first.
5080 -- A formal parameter of a specific tagged type whose related
5081 -- subprogram is subject to pragma Extensions_Visible with value
5082 -- "False" cannot act as an actual in a subprogram with value
5083 -- "True" (SPARK RM 6.1.7(3)).
5085 -- No check needed for helpers and indirect-call wrappers built to
5086 -- support class-wide preconditions.
5090 Extensions_Visible_True
5092 then
5093 Error_Msg_N
5096 Error_Msg_NE
5100 -- The actual parameter of a Ghost subprogram whose formal is of
5101 -- mode IN OUT or OUT must be a Ghost variable (SPARK RM 6.9(12)).
5109 then
5110 Error_Msg_NE
5116 else
5121 -- (AI12-0397): The target of a subprogram call that occurs within
5122 -- the expression of an Default_Initial_Condition aspect and has
5123 -- an actual that is the current instance of the type must be
5124 -- either a primitive of the type or a class-wide subprogram,
5125 -- because the type of the current instance in such an aspect is
5126 -- considered to be a notional formal derived type whose only
5127 -- operations correspond to the primitives of the enclosing type.
5128 -- Nonprimitives can be called, but the current instance must be
5129 -- converted rather than passed directly. Note that a current
5130 -- instance of a type with DIC will occur as a reference to an
5131 -- in-mode formal of an enclosing DIC procedure or partial DIC
5132 -- procedure. (It seems that this check should perhaps also apply
5133 -- to calls within Type_Invariant'Class, but not Type_Invariant,
5134 -- aspects???)
5142 -- We check Comes_From_Source to exclude inherited primitives
5143 -- from being flagged, because such subprograms turn out to not
5144 -- always have the Is_Primitive flag set. ???
5150 then
5151 Error_Msg_NE
5158 -- Case where actual is not present
5160 else
5161 Insert_Default;
5172 -----------------------
5173 -- Resolve_Allocator --
5174 -----------------------
5186 procedure Check_Allocator_Discrim_Accessibility
5189 -- Check that accessibility level associated with an access discriminant
5190 -- initialized in an allocator by the expression Disc_Exp is not deeper
5191 -- than the level of the allocator type Alloc_Typ. An error message is
5192 -- issued if this condition is violated. Specialized checks are done for
5193 -- the cases of a constraint expression which is an access attribute or
5194 -- an access discriminant.
5196 procedure Check_Allocator_Discrim_Accessibility_Exprs
5199 -- Dispatch checks performed by Check_Allocator_Discrim_Accessibility
5200 -- across all expressions within a given conditional expression.
5203 -- If the allocator is an actual in a call, it is allowed to be class-
5204 -- wide when the context is not because it is a controlling actual.
5206 -------------------------------------------
5207 -- Check_Allocator_Discrim_Accessibility --
5208 -------------------------------------------
5210 procedure Check_Allocator_Discrim_Accessibility
5213 is
5214 begin
5217 then
5218 Error_Msg_N
5221 -- When the expression is an Access attribute the level of the prefix
5222 -- object must not be deeper than that of the allocator's type.
5226 Attribute_Access
5227 and then Static_Accessibility_Level
5230 then
5231 Error_Msg_N
5233 Disc_Exp);
5235 -- When the expression is an access discriminant the check is against
5236 -- the level of the prefix object.
5240 and then Static_Accessibility_Level
5243 then
5244 Error_Msg_N
5246 Disc_Exp);
5248 -- All other cases are legal
5250 else
5255 -------------------------------------------------
5256 -- Check_Allocator_Discrim_Accessibility_Exprs --
5257 -------------------------------------------------
5259 procedure Check_Allocator_Discrim_Accessibility_Exprs
5262 is
5266 begin
5267 -- When conditional expressions are constant folded we know at
5268 -- compile time which expression to check - so don't bother with
5269 -- the rest of the cases.
5274 -- Non-constant-folded if expressions
5277 -- Check both expressions if they are still present in the face
5278 -- of expansion.
5285 Check_Allocator_Discrim_Accessibility_Exprs
5290 -- Non-constant-folded case expressions
5293 -- Check all alternatives
5297 Check_Allocator_Discrim_Accessibility_Exprs
5303 -- Base case, check the accessibility of the original node of the
5304 -- expression.
5306 else
5311 ----------------------------
5312 -- In_Dispatching_Context --
5313 ----------------------------
5318 begin
5324 -- Start of processing for Resolve_Allocator
5326 begin
5327 -- Replace general access with specific type
5337 -- For qualified expression, resolve the expression using the given
5338 -- subtype (nothing to do for type mark, subtype indication)
5343 and then not In_Dispatching_Context
5344 then
5345 Error_Msg_N
5349 -- Do a full resolution to apply constraint and predicate checks
5354 -- Allocators generated by the build-in-place expansion mechanism
5355 -- are explicitly marked as coming from source but do not need to be
5356 -- checked for limited initialization. To exclude this case, ensure
5357 -- that the parent of the allocator is a source node.
5358 -- The return statement constructed for an Expression_Function does
5359 -- not come from source but requires a limited check.
5363 and then
5365 or else
5369 and then not In_Instance_Body
5370 then
5373 Error_Msg_N
5376 else
5377 Error_Msg_N
5385 -- Calls to build-in-place functions are not currently supported in
5386 -- allocators for access types associated with a simple storage pool.
5387 -- Supporting such allocators may require passing additional implicit
5388 -- parameters to build-in-place functions (or a significant revision
5389 -- of the current b-i-p implementation to unify the handling for
5390 -- multiple kinds of storage pools). ???
5394 then
5395 declare
5398 begin
5400 and then
5401 Present (Get_Rep_Pragma
5403 then
5404 Error_Msg_N
5411 -- A special accessibility check is needed for allocators that
5412 -- constrain access discriminants. The level of the type of the
5413 -- expression used to constrain an access discriminant cannot be
5414 -- deeper than the type of the allocator (in contrast to access
5415 -- parameters, where the level of the actual can be arbitrary).
5417 -- We can't use Valid_Conversion to perform this check because in
5418 -- general the type of the allocator is unrelated to the type of
5419 -- the access discriminant.
5423 then
5430 then
5433 -- Get the first component expression of the aggregate
5443 else
5447 else
5453 Check_Allocator_Discrim_Accessibility_Exprs
5467 else
5472 else
5481 -- For a subtype mark or subtype indication, freeze the subtype
5483 else
5487 Error_Msg_N
5491 -- A special accessibility check is needed for allocators that
5492 -- constrain access discriminants. The level of the type of the
5493 -- expression used to constrain an access discriminant cannot be
5494 -- deeper than the type of the allocator (in contrast to access
5495 -- parameters, where the level of the actual can be arbitrary).
5496 -- We can't use Valid_Conversion to perform this check because
5497 -- in general the type of the allocator is unrelated to the type
5498 -- of the access discriminant.
5503 then
5513 else
5517 Check_Allocator_Discrim_Accessibility_Exprs
5528 -- Ada 2005 (AI-344): A class-wide allocator requires an accessibility
5529 -- check that the level of the type of the created object is not deeper
5530 -- than the level of the allocator's access type, since extensions can
5531 -- now occur at deeper levels than their ancestor types. This is a
5532 -- static accessibility level check; a run-time check is also needed in
5533 -- the case of an initialized allocator with a class-wide argument (see
5534 -- Expand_Allocator_Expression).
5538 then
5539 declare
5542 begin
5547 else
5553 then
5556 Error_Msg_N
5566 -- Do not apply Ada 2005 accessibility checks on a class-wide
5567 -- allocator if the type given in the allocator is a formal
5568 -- type or within a formal package. A run-time check will be
5569 -- performed in the instance.
5573 then
5574 Error_Msg_N
5582 -- Check for allocation from an empty storage pool. But do not complain
5583 -- if it's a return statement for a build-in-place function, because the
5584 -- allocator is there just in case the caller uses an allocator. If the
5585 -- caller does use an allocator, it will be caught at the call site.
5589 then
5592 -- If the context is an unchecked conversion, as may happen within an
5593 -- inlined subprogram, the allocator is being resolved with its own
5594 -- anonymous type. In that case, if the target type has a specific
5595 -- storage pool, it must be inherited explicitly by the allocator type.
5599 then
5600 Set_Associated_Storage_Pool
5608 -- Check that an allocator with task parts isn't for a nested access
5609 -- type when restriction No_Task_Hierarchy applies.
5613 then
5617 -- An illegal allocator may be rewritten as a raise Program_Error
5618 -- statement.
5622 -- Avoid coextension processing for an allocator that is the
5623 -- expansion of a build-in-place function call.
5627 N_Qualified_Expression
5629 N_Function_Call
5630 and then Is_Expanded_Build_In_Place_Call
5632 then
5635 else
5636 -- An anonymous access discriminant is the definition of a
5637 -- coextension.
5641 N_Discriminant_Specification
5642 then
5643 declare
5647 begin
5650 -- Ada 2012 AI05-0052: If the designated type of the
5651 -- allocator is limited, then the allocator shall not
5652 -- be used to define the value of an access discriminant
5653 -- unless the discriminated type is immutably limited.
5658 then
5659 Error_Msg_N
5662 N);
5666 -- Avoid marking an allocator as a dynamic coextension if it is
5667 -- within a static construct.
5672 -- Finalization and deallocation of coextensions utilizes an
5673 -- approximate implementation which does not directly adhere
5674 -- to the semantic rules. Warn on potential issues involving
5675 -- coextensions.
5678 Error_Msg_N
5681 else
5682 Error_Msg_N
5688 -- Cleanup for potential static coextensions
5690 else
5694 -- Anonymous access-to-controlled objects are not finalized on
5695 -- time because this involves run-time ownership and currently
5696 -- this property is not available. In rare cases the object may
5697 -- not be finalized at all. Warn on potential issues involving
5698 -- anonymous access-to-controlled objects.
5702 then
5703 Error_Msg_N
5713 -- Report a simple error: if the designated object is a local task,
5714 -- its body has not been seen yet, and its activation will fail an
5715 -- elaboration check.
5722 then
5728 -- Ada 2012 (AI05-0111-3): Detect an attempt to allocate a task or a
5729 -- type with a task component on a subpool. This action must raise
5730 -- Program_Error at runtime.
5736 then
5748 ---------------------------
5749 -- Resolve_Arithmetic_Op --
5750 ---------------------------
5752 -- Used for resolving all arithmetic operators except exponentiation
5763 -- We do the resolution using the base type, because intermediate values
5764 -- in expressions always are of the base type, not a subtype of it.
5767 -- Returns True if N is in a context that expects "any real type"
5770 -- Return True iff given type is Integer or universal real/integer
5773 -- Choose type of integer literal in fixed-point operation to conform
5774 -- to available fixed-point type. T is the type of the other operand,
5775 -- which is needed to determine the expected type of N.
5778 -- Set operand type to T if universal
5780 -------------------------------
5781 -- Expected_Type_Is_Any_Real --
5782 -------------------------------
5785 begin
5786 -- N is the expression after "delta" in a fixed_point_definition;
5787 -- see RM-3.5.9(6):
5790 | N_Decimal_Fixed_Point_Definition
5792 -- N is one of the bounds in a real_range_specification;
5793 -- see RM-3.5.7(5):
5795 | N_Real_Range_Specification
5797 -- N is the expression of a delta_constraint;
5798 -- see RM-J.3(3):
5800 | N_Delta_Constraint;
5803 -----------------------------
5804 -- Is_Integer_Or_Universal --
5805 -----------------------------
5812 begin
5817 else
5822 then
5833 ----------------------------
5834 -- Set_Mixed_Mode_Operand --
5835 ----------------------------
5841 begin
5844 -- A universal integer literal is resolved as standard integer
5845 -- except in the case of a fixed-point result, where we leave it
5846 -- as universal (to be handled by Exp_Fixd later on)
5850 else
5857 then
5858 -- A universal real can appear in a fixed-type context. We resolve
5859 -- the literal with that context, even though this might raise an
5860 -- exception prematurely (the other operand may be zero).
5867 then
5868 -- Integer arg in mixed-mode operation. Resolve with universal
5869 -- type, in case preference rule must be applied.
5875 -- If the operand is part of a fixed multiplication operation,
5876 -- a conversion will be applied to each operand, so resolve it
5877 -- with its own type.
5882 else
5883 -- Not a mixed-mode operation, resolve with context
5890 -- N may itself be a mixed-mode operation, so use context type
5897 then
5898 -- Must be (fixed * fixed) operation, operand must have one
5899 -- compatible interpretation.
5906 then
5907 -- C * F(X) in a fixed context, where C is a real literal or a
5908 -- fixed-point expression. F must have either a fixed type
5909 -- interpretation or an integer interpretation, but not both.
5916 else
5923 else
5931 -- Reanalyze the literal with the fixed type of the context. If
5932 -- context is Universal_Fixed, we are within a conversion, leave
5933 -- the literal as a universal real because there is no usable
5934 -- fixed type, and the target of the conversion plays no role in
5935 -- the resolution.
5937 declare
5941 begin
5944 else
5950 then
5952 else
5960 -- A universal real conditional expression can appear in a fixed-type
5961 -- context and must be resolved with that context to facilitate the
5962 -- code generation in the back end. However, If the context is
5963 -- Universal_fixed (i.e. as an operand of a multiplication/division
5964 -- involving a fixed-point operand) the conditional expression must
5965 -- resolve to a unique visible fixed_point type, normally Duration.
5970 then
5974 else
5978 else
5983 ----------------------
5984 -- Set_Operand_Type --
5985 ----------------------
5988 begin
5994 -- Start of processing for Resolve_Arithmetic_Op
5996 begin
6001 then
6005 -- Special-case for mixed-mode universal expressions or fixed point type
6006 -- operation: each argument is resolved separately. The same treatment
6007 -- is required if one of the operands of a fixed point operation is
6008 -- universal real, since in this case we don't do a conversion to a
6009 -- specific fixed-point type (instead the expander handles the case).
6011 -- Set the type of the node to its universal interpretation because
6012 -- legality checks on an exponentiation operand need the context.
6017 then
6028 or else
6031 then
6036 -- If context is a fixed type and one operand is integer, the other
6037 -- is resolved with the type of the context.
6042 then
6049 then
6053 -- If both operands are universal and the context is a floating
6054 -- point type, the operands are resolved to the type of the context.
6060 else
6065 -- Check the rule in RM05-4.5.5(19.1/2) disallowing universal_fixed
6066 -- multiplying operators from being used when the expected type is
6067 -- also universal_fixed. Note that B_Typ will be Universal_Fixed in
6068 -- some cases where the expected type is actually Any_Real;
6069 -- Expected_Type_Is_Any_Real takes care of that case.
6073 then
6077 N_Type_Conversion | N_Unchecked_Type_Conversion
6078 then
6085 else
6089 N_Type_Conversion | N_Unchecked_Type_Conversion
6090 then
6091 Error_Msg_N
6096 -- The expected type is "any real type" in contexts like
6098 -- type T is delta <universal_fixed-expression> ...
6100 -- in which case we need to set the type to Universal_Real
6101 -- so that static expression evaluation will work properly.
6105 else
6115 then
6120 -- If no previous errors, this is only possible if one operand is
6121 -- overloaded and the context is universal. Resolve as such.
6126 else
6128 and then
6130 then
6134 -- If the context is Universal_Fixed and the operands are also
6135 -- universal fixed, this is an error, unless there is only one
6136 -- applicable fixed_point type (usually Duration).
6144 else
6149 else
6154 -- If one of the arguments was resolved to a non-universal type.
6155 -- label the result of the operation itself with the same type.
6156 -- Do the same for the universal argument, if any.
6168 -- Set overflow and division checking bit
6175 -- Give warning if explicit division by zero
6179 then
6185 or else
6188 then
6189 -- Specialize the warning message according to the operation.
6190 -- When SPARK_Mode is On, force a warning instead of an error
6191 -- in that case, as this likely corresponds to deactivated
6192 -- code. The following warnings are for the case
6197 -- For division, we have two cases, for float division
6198 -- of an unconstrained float type, on a machine where
6199 -- Machine_Overflows is false, we don't get an exception
6200 -- at run-time, but rather an infinity or Nan. The Nan
6201 -- case is pretty obscure, so just warn about infinities.
6205 and then not Machine_Overflows_On_Target
6206 then
6207 Error_Msg_N
6211 -- For all other cases, we get a Constraint_Error
6213 else
6214 Apply_Compile_Time_Constraint_Error
6221 Apply_Compile_Time_Constraint_Error
6227 Apply_Compile_Time_Constraint_Error
6232 -- Division by zero can only happen with division, rem,
6233 -- and mod operations.
6239 -- Otherwise just set the flag to check at run time
6241 else
6246 -- If Restriction No_Implicit_Conditionals is active, then it is
6247 -- violated if either operand can be negative for mod, or for rem
6248 -- if both operands can be negative.
6252 then
6253 declare
6260 -- Set if corresponding operand might be negative
6262 begin
6263 Determine_Range
6267 Determine_Range
6271 -- Check if we will be generating conditionals. There are two
6272 -- cases where that can happen, first for REM, the only case
6273 -- is largest negative integer mod -1, where the division can
6274 -- overflow, but we still have to give the right result. The
6275 -- front end generates a test for this annoying case. Here we
6276 -- just test if both operands can be negative (that's what the
6277 -- expander does, so we match its logic here).
6279 -- The second case is mod where either operand can be negative.
6280 -- In this case, the back end has to generate additional tests.
6283 or else
6285 then
6296 ------------------
6297 -- Resolve_Call --
6298 ------------------
6313 begin
6314 -- Preserve relevant elaboration-related attributes of the context which
6315 -- are no longer available or very expensive to recompute once analysis,
6316 -- resolution, and expansion are over.
6318 Mark_Elaboration_Attributes
6324 -- The context imposes a unique interpretation with type Typ on a
6325 -- procedure or function call. Find the entity of the subprogram that
6326 -- yields the expected type, and propagate the corresponding formal
6327 -- constraints on the actuals. The caller has established that an
6328 -- interpretation exists, and emitted an error if not unique.
6330 -- First deal with the case of a call to an access-to-subprogram,
6331 -- dereference made explicit in Analyze_Call.
6337 else
6338 -- Find the interpretation whose type (a subprogram type) has a
6339 -- return type that is compatible with the context. Analysis of
6340 -- the node has established that one exists.
6359 -- If the prefix is not an entity, then resolve it
6365 -- For an indirect call, we always invalidate checks, since we do not
6366 -- know whether the subprogram is local or global. Yes we could do
6367 -- better here, e.g. by knowing that there are no local subprograms,
6368 -- but it does not seem worth the effort. Similarly, we kill all
6369 -- knowledge of current constant values.
6371 Kill_Current_Values;
6373 -- If this is a procedure call which is really an entry call, do
6374 -- the conversion of the procedure call to an entry call. Protected
6375 -- operations use the same circuitry because the name in the call
6376 -- can be an arbitrary expression with special resolution rules.
6380 then
6387 -- Annotate the tree by creating a call marker in case the original
6388 -- call is transformed by expansion. The call marker is automatically
6389 -- saved for later examination by the ABE Processing phase.
6393 -- Kill checks and constant values, as above for indirect case
6394 -- Who knows what happens when another task is activated?
6396 Kill_Current_Values;
6399 -- Normal subprogram call with name established in Resolve
6405 -- Otherwise we must have the case of an overloaded call
6407 else
6410 -- Initialize Nam to prevent warning (we know it will be assigned
6411 -- in the loop below, but the compiler does not know that).
6427 -- Check that a call to Current_Task does not occur in an entry body
6430 declare
6433 begin
6435 loop
6438 -- Exclude calls that occur within the default of a formal
6439 -- parameter of the entry, since those are evaluated outside
6440 -- of the body.
6447 then
6450 Error_Msg_NE
6464 -- Check that a procedure call does not occur in the context of the
6465 -- entry call statement of a conditional or timed entry call. Note that
6466 -- the case of a call to a subprogram renaming of an entry will also be
6467 -- rejected. The test for N not being an N_Entry_Call_Statement is
6468 -- defensive, covering the possibility that the processing of entry
6469 -- calls might reach this point due to later modifications of the code
6470 -- above.
6475 then
6479 -- Ada 2005 (AI-345): If a procedure_call_statement is used
6480 -- for a procedure_or_entry_call, the procedure_name or
6481 -- procedure_prefix of the procedure_call_statement shall denote
6482 -- an entry renamed by a procedure, or (a view of) a primitive
6483 -- subprogram of a limited interface whose first parameter is
6484 -- a controlling parameter.
6489 then
6490 Error_Msg_N
6495 -- Check that this is not a call to a protected procedure or entry from
6496 -- within a protected function.
6500 -- Freeze the subprogram name if not in a spec-expression. Note that
6501 -- we freeze procedure calls as well as function calls. Procedure calls
6502 -- are not frozen according to the rules (RM 13.14(14)) because it is
6503 -- impossible to have a procedure call to a non-frozen procedure in
6504 -- pure Ada, but in the code that we generate in the expander, this
6505 -- rule needs extending because we can generate procedure calls that
6506 -- need freezing.
6508 -- In Ada 2012, expression functions may be called within pre/post
6509 -- conditions of subsequent functions or expression functions. Such
6510 -- calls do not freeze when they appear within generated bodies,
6511 -- (including the body of another expression function) which would
6512 -- place the freeze node in the wrong scope. An expression function
6513 -- is frozen in the usual fashion, by the appearance of a real body,
6514 -- or at the end of a declarative part. However an implicit call to
6515 -- an expression function may appear when it is part of a default
6516 -- expression in a call to an initialization procedure, and must be
6517 -- frozen now, even if the body is inserted at a later point.
6518 -- Otherwise, the call freezes the expression if expander is active,
6519 -- for example as part of an object declaration.
6522 and then not In_Spec_Expression
6524 and then
6527 then
6530 -- Force freeze of expression function in call
6539 -- For a predefined operator, the type of the result is the type imposed
6540 -- by context, except for a predefined operation on universal fixed.
6541 -- Otherwise the type of the call is the type returned by the subprogram
6542 -- being called.
6549 -- If the subprogram returns an array type, and the context requires the
6550 -- component type of that array type, the node is really an indexing of
6551 -- the parameterless call. Resolve as such. A pathological case occurs
6552 -- when the type of the component is an access to the array type. In
6553 -- this case the call is truly ambiguous. If the call is to an intrinsic
6554 -- subprogram, it can't be an indexed component. This check is necessary
6555 -- because if it's Unchecked_Conversion, and we have "type T_Ptr is
6556 -- access T;" and "type T is array (...) of T_Ptr;" (i.e. an array of
6557 -- pointers to the same array), the compiler gets confused and does an
6558 -- infinite recursion.
6561 and then
6564 or else
6567 and then
6570 then
6571 declare
6576 begin
6577 -- If this is a parameterless call there is no ambiguity and the
6578 -- call has the type of the function.
6587 -- Annotate the tree by creating a call marker in case the
6588 -- original call is transformed by expansion. The call marker
6589 -- is automatically saved for later examination by the ABE
6590 -- Processing phase.
6597 then
6598 Error_Msg_N
6600 else
6603 -- The called entity may be an explicit dereference, in which
6604 -- case there is no entity to set.
6612 or else
6614 and then
6616 then
6619 -- Indexed call to a parameterless function
6621 Index_Node :=
6623 Prefix =>
6626 else
6627 -- An Ada 2005 prefixed call to a primitive operation
6628 -- whose first parameter is the prefix. This prefix was
6629 -- prepended to the parameter list, which is actually a
6630 -- list of indexes. Remove the prefix in order to build
6631 -- the proper indexed component.
6633 Index_Node :=
6635 Prefix =>
6638 Parameter_Associations =>
6639 New_List
6644 -- Preserve the parenthesis count of the node
6648 -- Since we are correcting a node classification error made
6649 -- by the parser, we call Replace rather than Rewrite.
6660 -- Annotate the tree by creating a call marker in case
6661 -- the original call is transformed by expansion. The call
6662 -- marker is automatically saved for later examination by
6663 -- the ABE Processing phase.
6674 else
6675 -- If the called function is not declared in the main unit and it
6676 -- returns the limited view of type then use the available view (as
6677 -- is done in Try_Object_Operation) to prevent back-end confusion;
6678 -- for the function entity itself. The call must appear in a context
6679 -- where the nonlimited view is available. If the function entity is
6680 -- in the extended main unit then no action is needed, because the
6681 -- back end handles this case. In either case the type of the call
6682 -- is the nonlimited view.
6686 then
6693 else
6698 -- In the case where the call is to an overloaded subprogram, Analyze
6699 -- calls Normalize_Actuals once per overloaded subprogram. Therefore in
6700 -- such a case Normalize_Actuals needs to be called once more to order
6701 -- the actuals correctly. Otherwise the call will have the ordering
6702 -- given by the last overloaded subprogram whether this is the correct
6703 -- one being called or not.
6710 -- In any case, call is fully resolved now. Reset Overload flag, to
6711 -- prevent subsequent overload resolution if node is analyzed again
6716 -- A Ghost entity must appear in a specific context
6722 -- If we are calling the current subprogram from immediately within its
6723 -- body, then that is the case where we can sometimes detect cases of
6724 -- infinite recursion statically. Do not try this in case restriction
6725 -- No_Recursion is in effect anyway, and do it only for source calls.
6730 -- Issue warning for possible infinite recursion in the absence
6731 -- of the No_Recursion restriction.
6737 then
6738 -- Here we detected and flagged an infinite recursion, so we do
6739 -- not need to test the case below for further warnings. Also we
6740 -- are all done if we now have a raise SE node.
6746 -- If call is to immediately containing subprogram, then check for
6747 -- the case of a possible run-time detectable infinite recursion.
6749 else
6753 -- Ada 2022 (AI12-0075): Static functions are never allowed
6754 -- to make a recursive call, as specified by 6.8(5.4/5).
6757 Error_Msg_N
6766 -- Although in general case, recursion is not statically
6767 -- checkable, the case of calling an immediately containing
6768 -- subprogram is easy to catch.
6774 -- If the recursive call is to a parameterless subprogram,
6775 -- then even if we can't statically detect infinite
6776 -- recursion, this is pretty suspicious, and we output a
6777 -- warning. Furthermore, we will try later to detect some
6778 -- cases here at run time by expanding checking code (see
6779 -- Detect_Infinite_Recursion in package Exp_Ch6).
6781 -- If the recursive call is within a handler, do not emit a
6782 -- warning, because this is a common idiom: loop until input
6783 -- is correct, catch illegal input in handler and restart.
6789 then
6790 -- For the case of a procedure call. We give the message
6791 -- only if the call is the first statement in a sequence
6792 -- of statements, or if all previous statements are
6793 -- simple assignments. This is simply a heuristic to
6794 -- decrease false positives, without losing too many good
6795 -- warnings. The idea is that these previous statements
6796 -- may affect global variables the procedure depends on.
6797 -- We also exclude raise statements, that may arise from
6798 -- constraint checks and are probably unrelated to the
6799 -- intended control flow.
6803 then
6804 declare
6806 begin
6810 | N_Raise_Constraint_Error
6811 then
6820 -- Do not give warning if we are in a conditional context
6822 declare
6824 begin
6830 then
6835 -- Here warning is to be issued
6851 -- Check obsolescent reference to Ada.Characters.Handling subprogram
6855 -- If subprogram name is a predefined operator, it was given in
6856 -- functional notation. Replace call node with operator node, so
6857 -- that actuals can be resolved appropriately.
6865 then
6871 -- Create a transient scope if the resulting type requires it
6873 -- There are several notable exceptions:
6875 -- a) In init procs, the transient scope overhead is not needed, and is
6876 -- even incorrect when the call is a nested initialization call for a
6877 -- component whose expansion may generate adjust calls. However, if the
6878 -- call is some other procedure call within an initialization procedure
6879 -- (for example a call to Create_Task in the init_proc of the task
6880 -- run-time record) a transient scope must be created around this call.
6882 -- b) Enumeration literal pseudo-calls need no transient scope
6884 -- c) Intrinsic subprograms (Unchecked_Conversion and source info
6885 -- functions) do not use the secondary stack even though the return
6886 -- type may be unconstrained.
6888 -- d) Calls to a build-in-place function, since such functions may
6889 -- allocate their result directly in a target object, and cases where
6890 -- the result does get allocated in the secondary stack are checked for
6891 -- within the specialized Exp_Ch6 procedures for expanding those
6892 -- build-in-place calls.
6894 -- e) Calls to inlinable expression functions do not use the secondary
6895 -- stack (since the call will be replaced by its returned object).
6897 -- f) If the subprogram is marked Inline_Always, then even if it returns
6898 -- an unconstrained type the call does not require use of the secondary
6899 -- stack. However, inlining will only take place if the body to inline
6900 -- is already present. It may not be available if e.g. the subprogram is
6901 -- declared in a child instance.
6903 -- g) If the subprogram is a static expression function and the call is
6904 -- a static call (the actuals are all static expressions), then we never
6905 -- want to create a transient scope (this could occur in the case of a
6906 -- static string-returning call).
6912 then
6920 then
6923 -- A return statement from an ignored Ghost function does not use the
6924 -- secondary stack (or any other one).
6926 elsif Expander_Active
6930 then
6933 -- If the call appears within the bounds of a loop, it will be
6934 -- rewritten and reanalyzed, nothing left to do here.
6941 -- A protected function cannot be called within the definition of the
6942 -- enclosing protected type, unless it is part of a pre/postcondition
6943 -- on another protected operation. This may appear in the entry wrapper
6944 -- created for an entry with preconditions.
6949 and then not In_Spec_Expression
6951 then
6952 Error_Msg_NE
6956 -- Propagate interpretation to actuals, and add default expressions
6957 -- where needed.
6962 -- Overloaded literals are rewritten as function calls, for purpose of
6963 -- resolution. After resolution, we can replace the call with the
6964 -- literal itself.
6970 -- Avoid validation, since it is a static function call
6976 -- If the subprogram is not global, then kill all saved values and
6977 -- checks. This is a bit conservative, since in many cases we could do
6978 -- better, but it is not worth the effort. Similarly, we kill constant
6979 -- values. However we do not need to do this for internal entities
6980 -- (unless they are inherited user-defined subprograms), since they
6981 -- are not in the business of molesting local values.
6983 -- If the flag Suppress_Value_Tracking_On_Calls is set, then we also
6984 -- kill all checks and values for calls to global subprograms. This
6985 -- takes care of the case where an access to a local subprogram is
6986 -- taken, and could be passed directly or indirectly and then called
6987 -- from almost any context.
6989 -- Note: we do not do this step till after resolving the actuals. That
6990 -- way we still take advantage of the current value information while
6991 -- scanning the actuals.
6993 -- We suppress killing values if we are processing the nodes associated
6994 -- with N_Freeze_Entity nodes. Otherwise the declaration of a tagged
6995 -- type kills all the values as part of analyzing the code that
6996 -- initializes the dispatch tables.
7000 or else Suppress_Value_Tracking_On_Call
7005 then
7006 Kill_Current_Values;
7009 -- If we are warning about unread OUT parameters, this is the place to
7010 -- set Last_Assignment for OUT and IN OUT parameters. We have to do this
7011 -- after the above call to Kill_Current_Values (since that call clears
7012 -- the Last_Assignment field of all local variables).
7017 then
7018 declare
7022 begin
7032 then
7042 -- If the subprogram is a primitive operation, check whether or not
7043 -- it is a correct dispatching call.
7047 then
7052 and then not In_Instance
7053 then
7057 -- If this is a dispatching call, generate the appropriate reference,
7058 -- for better source navigation in GNAT Studio.
7062 then
7065 -- Normal case, not a dispatching call: generate a call reference
7067 else
7075 -- Check for violation of restriction No_Specific_Termination_Handlers
7076 -- and warn on a potentially blocking call to Abort_Task.
7080 or else
7082 then
7089 -- A call to Ada.Real_Time.Timing_Events.Set_Handler to set a relative
7090 -- timing event violates restriction No_Relative_Delay (AI-0211). We
7091 -- need to check the second argument to determine whether it is an
7092 -- absolute or relative timing event.
7097 then
7101 -- Issue an error for a call to an eliminated subprogram. This routine
7102 -- will not perform the check if the call appears within a default
7103 -- expression.
7107 -- Implement rule in 12.5.1 (23.3/2): In an instance, if the actual is
7108 -- class-wide and the call dispatches on result in a context that does
7109 -- not provide a tag, the call raises Program_Error.
7112 and then In_Instance
7117 then
7118 -- Verify that none of the formals are controlling
7120 declare
7124 begin
7146 -- Check for calling a function with OUT or IN OUT parameter when the
7147 -- calling context (us right now) is not Ada 2012, so does not allow
7148 -- OUT or IN OUT parameters in function calls. Functions declared in
7149 -- a predefined unit are OK, as they may be called indirectly from a
7150 -- user-declared instantiation.
7156 then
7161 -- Check the dimensions of the actuals in the call. For function calls,
7162 -- propagate the dimensions from the returned type to N.
7166 -- All done, evaluate call and deal with elaboration issues
7174 -- Annotate the tree by creating a call marker in case the original call
7175 -- is transformed by expansion. The call marker is automatically saved
7176 -- for later examination by the ABE Processing phase.
7184 -- Ada 2022 (AI12-0075): If the call is a static call to a static
7185 -- expression function, then we want to "inline" the call, replacing
7186 -- it with the folded static result. This is not done if the checking
7187 -- for a potentially static expression is enabled or if an error has
7188 -- been posted on the call (which may be due to the check for recursive
7189 -- calls, in which case we don't want to fall into infinite recursion
7190 -- when doing the inlining).
7192 if not Checking_Potentially_Static_Expression
7196 then
7199 -- In GNATprove mode, expansion is disabled, but we want to inline some
7200 -- subprograms to facilitate formal verification. Indirect calls through
7201 -- a subprogram type or within a generic cannot be inlined. Inlining is
7202 -- performed only for calls subject to SPARK_Mode on.
7204 elsif GNATprove_Mode
7207 and then not Inside_A_Generic
7208 then
7215 -- Nothing to do if the subprogram is not eligible for inlining in
7216 -- GNATprove mode, or inlining is disabled with switch -gnatdm
7220 or else Debug_Flag_M
7221 then
7224 -- Calls cannot be inlined inside assertions, as GNATprove treats
7225 -- assertions as logic expressions. Only issue a message when the
7226 -- body has been seen, otherwise this leads to spurious messages
7227 -- on expression functions.
7230 Cannot_Inline
7234 -- Calls cannot be inlined inside default expressions
7237 Cannot_Inline
7240 -- Calls cannot be inlined inside quantified expressions, which
7241 -- are left in expression form for GNATprove. Since these
7242 -- expressions are only preanalyzed, we need to detect the failure
7243 -- to inline outside of the case for Full_Analysis below.
7246 Cannot_Inline
7249 -- Inlining should not be performed during preanalysis
7253 -- Do not inline calls inside expression functions or functions
7254 -- generated by the front end for subtype predicates, as this
7255 -- would prevent interpreting them as logical formulas in
7256 -- GNATprove. Only issue a message when the body has been seen,
7257 -- otherwise this leads to spurious messages on callees that
7258 -- are themselves expression functions.
7261 and then
7266 then
7269 then
7271 Cannot_Inline
7276 Cannot_Inline
7281 Cannot_Inline
7285 else
7286 Cannot_Inline
7292 -- Cannot inline a call inside the definition of a record type,
7293 -- typically inside the constraints of the type. Calls in
7294 -- default expressions are also not inlined, but this is
7295 -- filtered out above when testing In_Default_Expr.
7298 Cannot_Inline
7301 -- With the one-pass inlining technique, a call cannot be
7302 -- inlined if the corresponding body has not been seen yet.
7305 Cannot_Inline
7308 -- Nothing to do if there is no body to inline, indicating that
7309 -- the subprogram is not suitable for inlining in GNATprove
7310 -- mode.
7315 -- Calls cannot be inlined inside potentially unevaluated
7316 -- expressions, as this would create complex actions inside
7317 -- expressions, that are not handled by GNATprove.
7320 Cannot_Inline
7324 -- Calls cannot be inlined inside the conditions of while
7325 -- loops, as this would create complex actions inside
7326 -- the condition, that are not handled by GNATprove.
7329 Cannot_Inline
7332 -- Do not inline calls which would possibly lead to missing a
7333 -- type conversion check on an input parameter.
7336 Cannot_Inline
7340 -- Otherwise, inline the call, issuing an info message when
7341 -- -gnatd_f is set.
7343 else
7345 Error_Msg_NE
7356 -----------------------------
7357 -- Resolve_Case_Expression --
7358 -----------------------------
7366 begin
7378 -- When the expression is of a scalar subtype different from the
7379 -- result subtype, then insert a conversion to ensure the generation
7380 -- of a constraint check.
7390 -- Apply RM 4.5.7 (17/3): whether the expression is statically or
7391 -- dynamically tagged must be known statically.
7399 Error_Msg_N
7413 -------------------------------
7414 -- Resolve_Character_Literal --
7415 -------------------------------
7421 begin
7422 -- Verify that the character does belong to the type of the context
7427 -- Wide_Wide_Character literals must always be defined, since the set
7428 -- of wide wide character literals is complete, i.e. if a character
7429 -- literal is accepted by the parser, then it is OK for wide wide
7430 -- character (out of range character literals are rejected).
7435 -- Always accept character literal for type Any_Character, which
7436 -- occurs in error situations and in comparisons of literals, both
7437 -- of which should accept all literals.
7442 -- For Standard.Character or a type derived from it, check that the
7443 -- literal is in range.
7450 -- For Standard.Wide_Character or a type derived from it, check that the
7451 -- literal is in range.
7458 -- If the entity is already set, this has already been resolved in a
7459 -- generic context, or comes from expansion. Nothing else to do.
7464 -- Otherwise we have a user defined character type, and we can use the
7465 -- standard visibility mechanisms to locate the referenced entity.
7467 else
7480 -- If we fall through, then the literal does not match any of the
7481 -- entries of the enumeration type. This isn't just a constraint error
7482 -- situation, it is an illegality (see RM 4.2).
7484 Error_Msg_NE
7488 ---------------------------
7489 -- Resolve_Comparison_Op --
7490 ---------------------------
7492 -- Context requires a boolean type, and plays no role in resolution.
7493 -- Processing identical to that for equality operators. The result type is
7494 -- the base type, which matters when pathological subtypes of booleans with
7495 -- limited ranges are used.
7502 begin
7503 -- If this is an intrinsic operation which is not predefined, use the
7504 -- types of its declared arguments to resolve the possibly overloaded
7505 -- operands. Otherwise the operands are unambiguous and specify the
7506 -- expected type.
7511 else
7522 -- Skip remaining processing if already set to Any_Type
7528 -- Deal with other error cases
7532 T = Any_Character
7533 then
7536 else
7544 -- Resolve the operands if types OK
7553 -- Check comparison on unordered enumeration
7557 Error_Msg_NE
7567 --------------------------------
7568 -- Resolve_Declare_Expression --
7569 --------------------------------
7571 procedure Resolve_Declare_Expression
7574 is
7581 -- Use a tree traversal to replace each ocurrence of the name of
7582 -- a local object declared in the construct, with the corresponding
7583 -- entity. This replaces the usual way to perform name capture by
7584 -- visibility, because it is not possible to place on the scope
7585 -- stack the fake scope created for the analysis of the local
7586 -- declarations; such a scope conflicts with the transient scopes
7587 -- that may be generated if the expression includes function calls
7588 -- requiring finalization.
7590 -------------------
7591 -- Replace_Local --
7592 -------------------
7595 begin
7596 -- The identifier may be the prefix of a selected component,
7597 -- but not a selector name, because the local entities do not
7598 -- have a scope that can be named: a selected component whose
7599 -- selector is a homonym of a local entity must denote some
7600 -- global entity.
7605 and then
7608 then
7618 -- Start of processing for Resolve_Declare_Expression
7620 begin
7626 N_Object_Declaration | N_Object_Renaming_Declaration
7628 then
7636 -- The end of the declarative list is a freeze point for the
7637 -- local declarations.
7647 -----------------------------------------
7648 -- Resolve_Discrete_Subtype_Indication --
7649 -----------------------------------------
7651 procedure Resolve_Discrete_Subtype_Indication
7654 is
7658 begin
7666 else
7676 Error_Msg_NE
7679 -- Rewrite the constraint as a range of Typ
7680 -- to allow compilation to proceed further.
7692 else
7696 -- Additionally, we must check that the bounds are compatible
7697 -- with the given subtype, which might be different from the
7698 -- type of the context.
7702 -- ??? If the above check statically detects a Constraint_Error
7703 -- it replaces the offending bound(s) of the range R with a
7704 -- Constraint_Error node. When the itype which uses these bounds
7705 -- is frozen the resulting call to Duplicate_Subexpr generates
7706 -- a new temporary for the bounds.
7708 -- Unfortunately there are other itypes that are also made depend
7709 -- on these bounds, so when Duplicate_Subexpr is called they get
7710 -- a forward reference to the newly created temporaries and Gigi
7711 -- aborts on such forward references. This is probably sign of a
7712 -- more fundamental problem somewhere else in either the order of
7713 -- itype freezing or the way certain itypes are constructed.
7715 -- To get around this problem we call Remove_Side_Effects right
7716 -- away if either bounds of R are a Constraint_Error.
7718 declare
7722 begin
7738 -------------------------
7739 -- Resolve_Entity_Name --
7740 -------------------------
7742 -- Used to resolve identifiers and expanded names
7745 function Is_Assignment_Or_Object_Expression
7748 -- Determine whether node Context denotes an assignment statement or an
7749 -- object declaration whose expression is node Expr.
7752 -- Determine whether Expr is part of an N_Attribute_Reference
7753 -- expression.
7755 ----------------------------------------
7756 -- Is_Assignment_Or_Object_Expression --
7757 ----------------------------------------
7759 function Is_Assignment_Or_Object_Expression
7762 is
7763 begin
7766 then
7769 -- Check whether a construct that yields a name is the expression of
7770 -- an assignment statement or an object declaration.
7773 | N_Explicit_Dereference
7774 | N_Indexed_Component
7775 | N_Selected_Component
7776 | N_Slice
7778 or else
7780 | N_Unchecked_Type_Conversion
7782 then
7783 return
7784 Is_Assignment_Or_Object_Expression
7788 -- Otherwise the context is not an assignment statement or an object
7789 -- declaration.
7791 else
7796 -----------------------------
7797 -- Is_Attribute_Expression --
7798 -----------------------------
7802 begin
7807 -- Prevent the search from going too far
7819 -- Local variables
7824 -- Start of processing for Resolve_Entity_Name
7826 begin
7827 -- If garbage from errors, set to Any_Type and return
7834 -- Replace named numbers by corresponding literals. Note that this is
7835 -- the one case where Resolve_Entity_Name must reset the Etype, since
7836 -- it is currently marked as universal.
7846 -- For enumeration literals, we need to make sure that a proper style
7847 -- check is done, since such literals are overloaded, and thus we did
7848 -- not do a style check during the first phase of analysis.
7854 -- Case of (sub)type name appearing in a context where an expression
7855 -- is expected. This is legal if occurrence is a current instance.
7856 -- See RM 8.6 (17/3). It is also legal if the expression is
7857 -- part of a choice pattern for a case stmt/expr having a
7858 -- non-discrete selecting expression.
7864 -- Any other use is an error
7866 else
7867 Error_Msg_N
7871 -- Check discriminant use if entity is discriminant in current scope,
7872 -- i.e. discriminant of record or concurrent type currently being
7873 -- analyzed. Uses in corresponding body are unrestricted.
7878 then
7881 -- A parameterless generic function cannot appear in a context that
7882 -- requires resolution.
7887 -- In Ada 83 an OUT parameter cannot be read, but attributes of
7888 -- array types (i.e. bounds and length) are legal.
7896 or else Is_Assignment_Or_Object_Expression
7899 then
7904 -- In all other cases, just do the possible static evaluation
7906 else
7907 -- A deferred constant that appears in an expression must have a
7908 -- completion, unless it has been removed by in-place expansion of
7909 -- an aggregate. A constant that is a renaming does not need
7910 -- initialization.
7916 and then not In_Spec_Expression
7919 then
7923 then
7925 else
7926 Error_Msg_N
7936 -- When the entity appears in a parameter association, retrieve the
7937 -- related subprogram call.
7945 -- The following checks are only relevant when SPARK_Mode is on as
7946 -- they are not standard Ada legality rules.
7950 -- An effectively volatile object for reading must appear in
7951 -- non-interfering context (SPARK RM 7.1.3(10)).
7955 and then
7957 then
7958 SPARK_Msg_N
7963 -- Check for possible elaboration issues with respect to reads of
7964 -- variables. The act of renaming the variable is not considered a
7965 -- read as it simply establishes an alias.
7967 if Legacy_Elaboration_Checks
7969 and then Dynamic_Elaboration_Checks
7971 then
7976 -- The variable may eventually become a constituent of a single
7977 -- protected/task type. Record the reference now and verify its
7978 -- legality when analyzing the contract of the variable
7979 -- (SPARK RM 9.3).
7985 -- A Ghost entity must appear in a specific context
7992 -- We may be resolving an entity within expanded code, so a reference to
7993 -- an entity should be ignored when calculating effective use clauses to
7994 -- avoid inappropriate marking.
8001 -------------------
8002 -- Resolve_Entry --
8003 -------------------
8015 -- If the bounds of the entry family being called depend on task
8016 -- discriminants, build a new index subtype where a discriminant is
8017 -- replaced with the value of the discriminant of the target task.
8018 -- The target task is the prefix of the entry name in the call.
8020 -----------------------
8021 -- Actual_Index_Type --
8022 -----------------------
8032 -- If the bound is given by a discriminant, replace with a reference
8033 -- to the discriminant of the same name in the target task. If the
8034 -- entry name is the target of a requeue statement and the entry is
8035 -- in the current protected object, the bound to be used is the
8036 -- discriminal of the object (see Apply_Range_Check for details of
8037 -- the transformation).
8039 -----------------------------
8040 -- Actual_Discriminant_Ref --
8041 -----------------------------
8047 begin
8052 then
8058 then
8059 -- Note: here Bound denotes a discriminant of the corresponding
8060 -- record type tskV, whose discriminal is a formal of the
8061 -- init-proc tskVIP. What we want is the body discriminal,
8062 -- which is associated to the discriminant of the original
8063 -- concurrent type tsk.
8065 return New_Occurrence_Of
8068 else
8069 Ref :=
8079 -- Start of processing for Actual_Index_Type
8081 begin
8084 then
8087 else
8101 -- Start of processing for Resolve_Entry
8103 begin
8104 -- Find name of entry being called, and resolve prefix of name with its
8105 -- own type. The prefix can be overloaded, and the name and signature of
8106 -- the entry must be taken into account.
8110 -- Case of dealing with entry family within the current tasks
8114 else
8120 -- Entry call to an entry (or entry family) in the current task. This
8121 -- is legal even though the task will deadlock. Rewrite as call to
8122 -- current task.
8124 -- This can also be a call to an entry in an enclosing task. If this
8125 -- is a single task, we have to retrieve its name, because the scope
8126 -- of the entry is the task type, not the object. If the enclosing
8127 -- task is a task type, the identity of the task is given by its own
8128 -- self variable.
8130 -- Finally this can be a requeue on an entry of the same task or
8131 -- protected object.
8138 then
8139 -- S is an enclosing task or protected object. The concurrent
8140 -- declaration has been converted into a type declaration, and
8141 -- the object itself has an object declaration that follows
8142 -- the type in the same declarative part.
8154 -- Call to current task. Will be transformed into call to Self
8161 New_N :=
8164 Selector_Name =>
8171 then
8172 -- Use the entry name (which must be unique at this point) to find
8173 -- the prefix that returns the corresponding task/protected type.
8175 declare
8181 begin
8203 -- We do not resolve the prefix because an Entry_Family has no type,
8204 -- although it has the semantics of an array since it can be indexed.
8205 -- In order to perform the associated range check, we would need to
8206 -- build an array type on the fly and set it on the prefix, but this
8207 -- would be wasteful since only the index type matters. Therefore we
8208 -- attach this index type directly, so that Actual_Index_Expression
8209 -- can pick it up later in order to generate the range check.
8216 -- Generate a reference for the index when it denotes an entity
8222 -- Up to this point the expression could have been the actual in a
8223 -- simple entry call, and be given by a named association.
8227 else
8233 ------------------------
8234 -- Resolve_Entry_Call --
8235 ------------------------
8246 begin
8247 -- We kill all checks here, because it does not seem worth the effort to
8248 -- do anything better, an entry call is a big operation.
8250 Kill_All_Checks;
8252 -- Processing of the name is similar for entry calls and protected
8253 -- operation calls. Once the entity is determined, we can complete
8254 -- the resolution of the actuals.
8256 -- The selector may be overloaded, in the case of a protected object
8257 -- with overloaded functions. The type of the context is used for
8258 -- resolution.
8263 then
8264 declare
8268 begin
8287 -- Simple entry or protected operation call
8300 -- Call to member of entry family
8307 -- We cannot in general check the maximum depth of protected entry calls
8308 -- at compile time. But we can tell that any protected entry call at all
8309 -- violates a specified nesting depth of zero.
8315 -- Use context type to disambiguate a protected function that can be
8316 -- called without actuals and that returns an array type, and where the
8317 -- argument list may be an indexing of the returned value.
8322 and then
8328 and then
8329 Covers
8332 then
8333 declare
8336 begin
8337 Index_Node :=
8339 Prefix =>
8343 -- Since we are correcting a node classification error made by the
8344 -- parser, we call Replace rather than Rewrite.
8357 then
8358 -- Note the entity being called before rewriting the call, so that
8359 -- it appears used at this point.
8363 -- Rewrite as call to the precondition wrapper, adding the task
8364 -- object to the list of actuals. If the call is to a member of an
8365 -- entry family, include the index as well.
8367 declare
8371 begin
8380 New_Call :=
8382 Name =>
8387 -- Preanalyze and resolve new call. Current procedure is called
8388 -- from Resolve_Call, after which expansion will take place.
8395 -- The operation name may have been overloaded. Order the actuals
8396 -- according to the formals of the resolved entity, and set the return
8397 -- type to that of the operation.
8404 -- Reset the Is_Overloaded flag, since resolution is now completed
8406 -- Simple entry call
8411 -- Call to a member of an entry family
8421 -- Create a call reference to the entry
8429 -- Verify that a procedure call cannot masquerade as an entry
8430 -- call where an entry call is expected.
8435 then
8440 then
8445 then
8450 -- After resolution, entry calls and protected procedure calls are
8451 -- changed into entry calls, for expansion. The structure of the node
8452 -- does not change, so it can safely be done in place. Protected
8453 -- function calls must keep their structure because they are
8454 -- subexpressions.
8458 -- A protected operation that is not a function may modify the
8459 -- corresponding object, and cannot apply to a constant. If this
8460 -- is an internal call, the prefix is the type itself.
8466 then
8467 Error_Msg_N
8469 Entry_Name);
8472 declare
8475 begin
8476 Entry_Call :=
8481 -- Inherit relevant attributes from the original call
8483 Set_First_Named_Actual
8486 Set_Is_Elaboration_Checks_OK_Node
8489 Set_Is_Elaboration_Warnings_OK_Node
8492 Set_Is_SPARK_Mode_On_Node
8499 -- Protected functions can return on the secondary stack, in which case
8500 -- we must trigger the transient scope mechanism.
8502 elsif Expander_Active
8504 then
8508 -- Now we know that this is not a call to a function that returns an
8509 -- array type; moreover, we know the name of the called entry. Detect
8510 -- overlapping actuals, just like for a subprogram call.
8516 -------------------------
8517 -- Resolve_Equality_Op --
8518 -------------------------
8520 -- Both arguments must have the same type, and the boolean context does
8521 -- not participate in the resolution. The first pass verifies that the
8522 -- interpretation is not ambiguous, and the type of the left argument is
8523 -- correctly set, or is Any_Type in case of ambiguity. If both arguments
8524 -- are strings or aggregates, allocators, or Null, they are ambiguous even
8525 -- though they carry a single (universal) type. Diagnose this case here.
8533 -- The resolution rule for if expressions requires that each such must
8534 -- have a unique type. This means that if several dependent expressions
8535 -- are of a non-null anonymous access type, and the context does not
8536 -- impose an expected type (as can be the case in an equality operation)
8537 -- the expression must be rejected.
8540 -- Attempt to explain the nature of a redundant comparison with True. If
8541 -- the expression N is too complex, this routine issues a general error
8542 -- message.
8545 -- In the case of allocators and access attributes, the context must
8546 -- provide an indication of the specific access type to be used. If
8547 -- one operand is of such a "generic" access type, check whether there
8548 -- is a specific visible access type that has the same designated type.
8549 -- This is semantically dubious, and of no interest to any real code,
8550 -- but c48008a makes it all worthwhile.
8553 -- Returns True iff the parent node is a and/or/xor operation that
8554 -- could be the cause of confused priorities. Note that if the not is
8555 -- in parens, then False is returned.
8557 -------------------------
8558 -- Check_If_Expression --
8559 -------------------------
8565 begin
8572 then
8578 ------------------------
8579 -- Explain_Redundancy --
8580 ------------------------
8587 begin
8590 -- Strip the operand down to an entity
8592 loop
8595 else
8600 -- The construct denotes an entity
8605 -- Do not generate an error message when the comparison is done
8606 -- against the enumeration literal Standard.True.
8610 -- Build a customized error message
8637 -- The construct is too complex to disect, issue a general message
8639 else
8644 -----------------------------
8645 -- Find_Unique_Access_Type --
8646 -----------------------------
8653 begin
8655 then
8659 then
8661 else
8673 then
8686 ----------------------------------
8687 -- Suspicious_Prio_For_Equality --
8688 ----------------------------------
8693 begin
8694 -- Check if parent node is one of and/or/xor, not parenthesized
8695 -- explicitly, and its own parent is not of this kind. Otherwise,
8696 -- it's a case of chained Boolean conditions which is likely well
8697 -- parenthesized.
8702 then
8703 declare
8707 else
8709 begin
8710 -- Compar may have been rewritten, for example from (a /= b)
8711 -- into not (a = b). Use the Original_Node instead.
8715 -- If the other argument of the and/or/xor is also a
8716 -- comparison, or another and/or/xor then most likely
8717 -- the priorities are correctly set.
8722 else
8727 -- Start of processing for Resolve_Equality_Op
8729 begin
8740 T = Any_Character
8741 then
8744 else
8753 then
8762 -- If expressions must have a single type, and if the context does
8763 -- not impose one the dependent expressions cannot be anonymous
8764 -- access types.
8766 -- Why no similar processing for case expressions???
8771 then
8779 -- If the unique type is a class-wide type then it will be expanded
8780 -- into a dispatching call to the predefined primitive. Therefore we
8781 -- check here for potential violation of such restriction.
8787 -- Only warn for redundant equality comparison to True for objects
8788 -- (e.g. "X = True") and operations (e.g. "(X < Y) = True"). For
8789 -- other expressions, it may be a matter of preference to write
8790 -- "Expr = True" or "Expr".
8792 if Warn_On_Redundant_Constructs
8797 and then
8799 or else
8801 then
8802 Error_Msg_N -- CODEFIX
8807 -- Warn on a (in)equality between boolean values which is not
8808 -- parenthesized when the parent expression is one of and/or/xor, as
8809 -- this is interpreted as (a = b) op c where most likely a = (b op c)
8810 -- was intended. Do not generate a warning in generic instances, as
8811 -- the problematic expression may be implicitly parenthesized in
8812 -- the generic itself if one of the operators is a generic formal.
8813 -- Also do not generate a warning for generated equality, for
8814 -- example from rewritting a membership test.
8816 if Warn_On_Questionable_Missing_Parens
8817 and then not In_Instance
8820 and then Suspicious_Prio_For_Equality
8821 then
8825 -- If the equality is overloaded and the operands have resolved
8826 -- properly, set the proper equality operator on the node. The
8827 -- current setting is the first one found during analysis, which
8828 -- is not necessarily the one to which the node has resolved.
8831 declare
8835 begin
8838 -- If the equality is user-defined, the type of the operands
8839 -- matches that of the formals. For a predefined operator,
8840 -- it is the scope that matters, given that the predefined
8841 -- equality has Any_Type formals. In either case the result
8842 -- type (most often Boolean) must match the context. The scope
8843 -- is either that of the type, if there is a generated equality
8844 -- (when there is an equality for the component type), or else
8845 -- Standard otherwise.
8849 and then
8853 then
8863 -- If expansion is active and this is an inherited operation,
8864 -- replace it with its ancestor. This must not be done during
8865 -- preanalysis because the type may not be frozen yet, as when
8866 -- the context is a precondition or postcondition.
8879 -- If this is an inequality, it may be the implicit inequality
8880 -- created for a user-defined operation, in which case the corres-
8881 -- ponding equality operation is not intrinsic, and the operation
8882 -- cannot be constant-folded. Else fold.
8887 or else Is_Intrinsic_Subprogram
8889 then
8895 then
8899 -- Ada 2005: If one operand is an anonymous access type, convert the
8900 -- other operand to it, to ensure that the underlying types match in
8901 -- the back-end. Same for access_to_subprogram, and the conversion
8902 -- verifies that the types are subtype conformant.
8904 -- We apply the same conversion in the case one of the operands is a
8905 -- private subtype of the type of the other.
8907 -- Why the Expander_Active test here ???
8909 if Expander_Active
8910 and then
8912 | E_Anonymous_Access_Subprogram_Type
8914 then
8928 ----------------------------------
8929 -- Resolve_Explicit_Dereference --
8930 ----------------------------------
8938 -- The candidate prefix type, if overloaded
8943 begin
8947 -- A useful optimization: check whether the dereference denotes an
8948 -- element of a container, and if so rewrite it as a call to the
8949 -- corresponding Element function.
8951 -- Disabled for now, on advice of ARG. A more restricted form of the
8952 -- predicate might be acceptable ???
8954 -- if Is_Container_Element (N) then
8955 -- return;
8956 -- end if;
8960 -- Use the context type to select the prefix that has the correct
8961 -- designated type. Keep the first match, which will be the inner-
8962 -- most.
8969 then
8974 -- Remove access types that do not match, but preserve access
8975 -- to subprogram interpretations, in case a further dereference
8976 -- is needed (see below).
8989 else
8990 -- If no interpretation covers the designated type of the prefix,
8991 -- this is the pathological case where not all implementations of
8992 -- the prefix allow the interpretation of the node as a call. Now
8993 -- that the expected type is known, Remove other interpretations
8994 -- from prefix, rewrite it as a call, and resolve again, so that
8995 -- the proper call node is generated.
9006 New_N :=
9008 Name =>
9019 -- If not overloaded, resolve P with its own type
9021 else
9025 -- If the prefix might be null, add an access check
9029 then
9033 -- If the designated type is a packed unconstrained array type, and the
9034 -- explicit dereference is not in the context of an attribute reference,
9035 -- then we must compute and set the actual subtype, since it is needed
9036 -- by Gigi. The reason we exclude the attribute case is that this is
9037 -- handled fine by Gigi, and in fact we use such attributes to build the
9038 -- actual subtype. We also exclude generated code (which builds actual
9039 -- subtypes directly if they are needed).
9045 then
9051 -- Note: No Eval processing is required for an explicit dereference,
9052 -- because such a name can never be static.
9056 -------------------------------------
9057 -- Resolve_Expression_With_Actions --
9058 -------------------------------------
9063 -- True if Act is an action of a declare_expression that is allowed in a
9064 -- static declare_expression.
9067 -- True if all actions of N are allowed in a static declare_expression.
9070 -- Expr is an expression with compile-time-known value. This returns the
9071 -- literal node that reprsents that value.
9074 begin
9079 then
9089 -- No other declarations, nor even pragmas, are allowed in a
9090 -- declare expression, so if we see something else, it must be
9091 -- an internally generated expression_with_actions.
9100 begin
9115 begin
9120 else
9129 pragma Assert
9137 begin
9144 -- If the value of the expression is known at compile time, and all
9145 -- of the actions (if any) are suitable, then replace the declare
9146 -- expression with its expression. This allows the declare expression
9147 -- as a whole to be static if appropriate. See AI12-0368.
9153 Rewrite
9160 ----------------------------------
9161 -- Resolve_Generalized_Indexing --
9162 ----------------------------------
9166 begin
9171 ---------------------------
9172 -- Resolve_If_Expression --
9173 ---------------------------
9177 -- When a dependent expression is of a subtype different from
9178 -- the context subtype, then insert a qualification to ensure
9179 -- the generation of a constraint check. This was previously
9180 -- for scalar types. For array types apply a length check, given
9181 -- that the context in general allows sliding, while a qualified
9182 -- expression forces equality of bounds.
9185 -- So in most cases the type of the If_Expression and of its
9186 -- dependent expressions is that of the context. However, if
9187 -- the expression is the index of an Indexed_Component, we must
9188 -- ensure that a proper index check is applied, rather than a
9189 -- range check on the index type (which might be discriminant
9190 -- dependent). In this case we resolve with the base type of the
9191 -- index type, and the index check is generated in the resolution
9192 -- of the indexed_component above.
9194 -----------------
9195 -- Apply_Check --
9196 -----------------
9202 begin
9207 or else Inside_A_Generic
9208 then
9214 else
9224 -- Local variables
9230 -- Start of processing for Resolve_If_Expression
9232 begin
9233 -- Defend against malformed expressions
9242 then
9258 -- If ELSE expression present, just resolve using the determined type
9259 -- If type is universal, resolve to any member of the class.
9268 else
9274 -- Apply RM 4.5.7 (17/3): whether the expression is statically or
9275 -- dynamically tagged must be known statically.
9280 then
9286 -- If no ELSE expression is present, root type must be Standard.Boolean
9287 -- and we provide a Standard.True result converted to the appropriate
9288 -- Boolean type (in case it is a derived boolean type).
9291 Else_Expr :=
9296 else
9310 ----------------------------------
9311 -- Resolve_Implicit_Dereference --
9312 ----------------------------------
9317 begin
9318 -- In an instance the proper view may not always be correct for
9319 -- private types, see e.g. Sem_Type.Covers for similar handling.
9324 and then In_Instance
9325 then
9336 -------------------------------
9337 -- Resolve_Indexed_Component --
9338 -------------------------------
9346 begin
9354 -- Use the context type to select the prefix that yields the correct
9355 -- component type.
9357 declare
9363 begin
9370 and then
9371 Covers
9374 then
9383 else
9389 else
9400 else
9407 -- If the prefix's type is an access type, get to the real array type.
9408 -- Note: we do not apply an access check because an explicit dereference
9409 -- will be introduced later, and the check will happen there.
9415 -- If name was overloaded, set component type correctly now.
9416 -- If a misplaced call to an entry family (which has no index types)
9417 -- return. Error will be diagnosed from calling context.
9421 else
9428 -- The prefix may have resolved to a string literal, in which case its
9429 -- etype has a special representation. This is only possible currently
9430 -- if the prefix is a static concatenation, written in functional
9431 -- notation.
9436 else
9451 -- Do not generate the warning on suspicious index if we are analyzing
9452 -- package Ada.Tags; otherwise we will report the warning with the
9453 -- Prims_Ptr field of the dispatch table.
9456 or else not
9458 then
9463 -- If the array type is atomic and the component is not, then this is
9464 -- worth a warning before Ada 2022, since we have a situation where the
9465 -- access to the component may cause extra read/writes of the atomic
9466 -- object, or partial word accesses, both of which may be unexpected.
9472 and then Has_Atomic_Components
9476 then
9477 Error_Msg_N
9479 Error_Msg_N
9484 -----------------------------
9485 -- Resolve_Integer_Literal --
9486 -----------------------------
9489 begin
9494 --------------------------------
9495 -- Resolve_Intrinsic_Operator --
9496 --------------------------------
9505 -- If the operand is a literal, it cannot be the expression in a
9506 -- conversion. Use a qualified expression instead.
9508 ---------------------
9509 -- Convert_Operand --
9510 ---------------------
9516 begin
9518 Res :=
9524 else
9531 -- Start of processing for Resolve_Intrinsic_Operator
9533 begin
9534 -- We must preserve the original entity in a generic setting, so that
9535 -- the legality of the operation can be verified in an instance.
9550 -- If the result or operand types are private, rewrite with unchecked
9551 -- conversions on the operands and the result, to expose the proper
9552 -- underlying numeric type.
9557 then
9562 else
9583 then
9584 -- Add explicit conversion where needed, and save interpretations in
9585 -- case operands are overloaded.
9592 else
9598 else
9608 else
9613 --------------------------------------
9614 -- Resolve_Intrinsic_Unary_Operator --
9615 --------------------------------------
9617 procedure Resolve_Intrinsic_Unary_Operator
9620 is
9625 begin
9644 else
9649 ------------------------
9650 -- Resolve_Logical_Op --
9651 ------------------------
9656 begin
9659 -- Predefined operations on scalar types yield the base type. On the
9660 -- other hand, logical operations on arrays yield the type of the
9661 -- arguments (and the context).
9665 else
9669 -- The following test is required because the operands of the operation
9670 -- may be literals, in which case the resulting type appears to be
9671 -- compatible with a signed integer type, when in fact it is compatible
9672 -- only with modular types. If the context itself is universal, the
9673 -- operation is illegal.
9681 Error_Msg_N
9689 then
9693 -- Replace AND by AND THEN, or OR by OR ELSE, if Short_Circuit_And_Or
9694 -- is active and the result type is standard Boolean (do not mess with
9695 -- ops that return a nonstandard Boolean type, because something strange
9696 -- is going on).
9698 -- Note: you might expect this replacement to be done during expansion,
9699 -- but that doesn't work, because when the pragma Short_Circuit_And_Or
9700 -- is used, no part of the right operand of an "and" or "or" operator
9701 -- should be executed if the left operand would short-circuit the
9702 -- evaluation of the corresponding "and then" or "or else". If we left
9703 -- the replacement to expansion time, then run-time checks associated
9704 -- with such operands would be evaluated unconditionally, due to being
9705 -- before the condition prior to the rewriting as short-circuit forms
9706 -- during expansion.
9708 if Short_Circuit_And_Or
9711 then
9712 -- Mark the corresponding putative SCO operator as truly a logical
9713 -- (and short-circuit) operator.
9726 -- Case of OR changed to OR ELSE
9728 else
9736 -- Return now, since analysis of the rewritten ops will take care of
9737 -- other reference bookkeeping and expression folding.
9753 ---------------------------
9754 -- Resolve_Membership_Op --
9755 ---------------------------
9757 -- The context can only be a boolean type, and does not determine the
9758 -- arguments. Arguments should be unambiguous, but the preference rule for
9759 -- universal types applies.
9769 -- Analysis has determined a unique type for the left operand. Use it as
9770 -- the basis to resolve the disjuncts.
9772 ----------------------------
9773 -- Resolve_Set_Membership --
9774 ----------------------------
9779 begin
9780 -- If the left operand is overloaded, find type compatible with not
9781 -- overloaded alternative of the right operand.
9790 else
9795 -- Unclear how to resolve expression if all alternatives are also
9796 -- overloaded.
9802 else
9811 -- Alternative is an expression, a range
9812 -- or a subtype mark.
9816 then
9823 -- Check for duplicates for discrete case
9826 declare
9835 begin
9836 -- Loop checking duplicates. This is quadratic, but giant sets
9837 -- are unlikely in this context so it's a reasonable choice.
9844 | N_Character_Literal
9845 | N_Has_Entity
9846 then
9863 -- RM 4.5.2 (28.1/3) specifies that for types other than records or
9864 -- limited types, evaluation of a membership test uses the predefined
9865 -- equality for the type. This may be confusing to users, and the
9866 -- following warning appears useful for the most common case.
9870 then
9871 Error_Msg_NE
9873 Error_Msg_N
9878 -- Start of processing for Resolve_Membership_Op
9880 begin
9886 Resolve_Set_Membership;
9892 then
9895 -- Ada 2005 (AI-251): Support the following case:
9897 -- type I is interface;
9898 -- type T is tagged ...
9900 -- function Test (O : I'Class) is
9901 -- begin
9902 -- return O in T'Class.
9903 -- end Test;
9905 -- In this case we have nothing else to do. The membership test will be
9906 -- done at run time.
9912 then
9914 else
9918 -- If mixed-mode operations are present and operands are all literal,
9919 -- the only interpretation involves Duration, which is probably not
9920 -- the intention of the programmer.
9935 then
9941 else
9946 -- Here after resolving membership operation
9953 ------------------
9954 -- Resolve_Null --
9955 ------------------
9960 begin
9961 -- Handle restriction against anonymous null access values This
9962 -- restriction can be turned off using -gnatdj.
9964 -- Ada 2005 (AI-231): Remove restriction
9967 and then not Debug_Flag_J
9970 then
9971 -- In the common case of a call which uses an explicitly null value
9972 -- for an access parameter, give specialized error message.
9975 Error_Msg_N
9978 -- Standard message for all other cases (are there any?)
9980 else
9981 Error_Msg_N
9986 -- Ada 2005 (AI-231): Generate the null-excluding check in case of
9987 -- assignment to a null-excluding object.
9992 then
9995 -- Decide whether to generate an if_statement around our
9996 -- null-excluding check to avoid them on certain internal object
9997 -- declarations by looking at the type the current Init_Proc
9998 -- belongs to.
10000 -- Generate:
10001 -- if T1b_skip_null_excluding_check then
10002 -- [constraint_error "access check failed"]
10003 -- end if;
10005 if Needs_Conditional_Null_Excluding_Check
10007 then
10010 Condition =>
10012 New_External_Name
10014 Then_Statements =>
10015 New_List (
10019 -- Otherwise, simply create the check
10021 else
10026 else
10027 Insert_Action
10035 -- In a distributed context, null for a remote access to subprogram may
10036 -- need to be replaced with a special record aggregate. In this case,
10037 -- return after having done the transformation.
10042 then
10046 -- The null literal takes its type from the context
10051 -----------------------
10052 -- Resolve_Op_Concat --
10053 -----------------------
10057 -- We wish to avoid deep recursion, because concatenations are often
10058 -- deeply nested, as in A&B&...&Z. Therefore, we walk down the left
10059 -- operands nonrecursively until we find something that is not a simple
10060 -- concatenation (A in this case). We resolve that, and then walk back
10061 -- up the tree following Parent pointers, calling Resolve_Op_Concat_Rest
10062 -- to do the rest of the work at each level. The Parent pointers allow
10063 -- us to avoid recursion, and thus avoid running out of memory. See also
10064 -- Sem_Ch4.Analyze_Concatenation, where a similar approach is used.
10069 begin
10070 -- The following code is equivalent to:
10072 -- Resolve_Op_Concat_First (NN, Typ);
10073 -- Resolve_Op_Concat_Arg (N, ...);
10074 -- Resolve_Op_Concat_Rest (N, Typ);
10076 -- where the Resolve_Op_Concat_Arg call recurses back here if the left
10077 -- operand is a concatenation.
10079 -- Walk down left operands
10081 loop
10090 -- Now (given the above example) NN is A&B and Op1 is A
10092 -- First resolve Op1 ...
10096 -- ... then walk NN back up until we reach N (where we started), calling
10097 -- Resolve_Op_Concat_Rest along the way.
10099 loop
10106 ---------------------------
10107 -- Resolve_Op_Concat_Arg --
10108 ---------------------------
10110 procedure Resolve_Op_Concat_Arg
10115 is
10119 begin
10121 if Is_Comp
10125 then
10127 else
10131 -- If both Array & Array and Array & Component are visible, there is a
10132 -- potential ambiguity that must be reported.
10137 then
10141 -- If the operation is user-defined and not overloaded use its
10142 -- profile. The operation may be a renaming, in which case it has
10143 -- been rewritten, and we want the original profile.
10148 then
10150 Etype
10154 -- Otherwise an aggregate may match both the array type and the
10155 -- component type.
10157 else
10162 else
10166 then
10167 declare
10172 begin
10177 -- Special-case the error message when the overloading is
10178 -- caused by a function that yields an array and can be
10179 -- called without parameters.
10184 Error_Msg_NE
10186 Error_Msg_NE
10190 else
10198 or else
10200 then
10201 Error_Msg_N -- CODEFIX
10219 else
10224 else
10231 -----------------------------
10232 -- Resolve_Op_Concat_First --
10233 -----------------------------
10240 begin
10241 -- The parser folds an enormous sequence of concatenations of string
10242 -- literals into "" & "...", where the Is_Folded_In_Parser flag is set
10243 -- in the right operand. If the expression resolves to a predefined "&"
10244 -- operator, all is well. Otherwise, the parser's folding is wrong, so
10245 -- we give an error. See P_Simple_Expression in Par.Ch4.
10250 then
10265 ----------------------------
10266 -- Resolve_Op_Concat_Rest --
10267 ----------------------------
10273 begin
10282 -- If this is not a static concatenation, but the result is a string
10283 -- type (and not an array of strings) ensure that static string operands
10284 -- have their subtypes properly constructed.
10288 then
10294 ----------------------
10295 -- Resolve_Op_Expon --
10296 ----------------------
10301 begin
10302 -- Catch attempts to do fixed-point exponentiation with universal
10303 -- operands, which is a case where the illegality is not caught during
10304 -- normal operator analysis. This is not done in preanalysis mode
10305 -- since the tree is not fully decorated during preanalysis.
10317 then
10327 then
10336 -- We do the resolution using the base type, because intermediate values
10337 -- in expressions are always of the base type, not a subtype of it.
10342 -- For integer types, right argument must be in Natural range
10357 -- Evaluate the exponentiation operator for dimensioned type
10360 else
10364 -- Set overflow checking bit. Much cleverer code needed here eventually
10365 -- and perhaps the Resolve routines should be separated for the various
10366 -- arithmetic operations, since they will need different processing. ???
10375 --------------------
10376 -- Resolve_Op_Not --
10377 --------------------
10381 -- This function determines if the parent node is a boolean operator or
10382 -- operation (comparison op, membership test, or short circuit form) and
10383 -- the not in question is the left operand of this operation. Note that
10384 -- if the not is in parens, then false is returned.
10386 -----------------------
10387 -- Parent_Is_Boolean --
10388 -----------------------
10391 begin
10394 | N_Op_Boolean
10395 | N_Short_Circuit
10399 -- Local variables
10403 -- Start of processing for Resolve_Op_Not
10405 begin
10406 -- Predefined operations on scalar types yield the base type. On the
10407 -- other hand, logical operations on arrays yield the type of the
10408 -- arguments (and the context).
10412 else
10416 -- Straightforward case of incorrect arguments
10423 -- Special case of probable missing parens
10427 Error_Msg_N
10430 else
10431 Error_Msg_N
10438 -- OK resolution of NOT
10440 else
10441 -- Warn if non-boolean types involved. This is a case like not a < b
10442 -- where a and b are modular, where we will get (not a) < b and most
10443 -- likely not (a < b) was intended.
10445 if Warn_On_Questionable_Missing_Parens
10447 and then Parent_Is_Boolean
10448 then
10452 -- Warn on double negation if checking redundant constructs
10454 if Warn_On_Redundant_Constructs
10459 then
10463 -- Complete resolution and evaluation of NOT
10464 -- If argument is an equality and expected type is boolean, that
10465 -- expected type has no effect on resolution, and there are
10466 -- special rules for resolution of Eq, Neq in the presence of
10467 -- overloaded operands, so we directly call its resolution routines.
10469 declare
10473 begin
10477 then
10483 then
10493 else
10506 -----------------------------
10507 -- Resolve_Operator_Symbol --
10508 -----------------------------
10510 -- Nothing to be done, all resolved already
10516 begin
10520 ----------------------------------
10521 -- Resolve_Qualified_Expression --
10522 ----------------------------------
10530 begin
10533 -- A qualified expression requires an exact match of the type, class-
10534 -- wide matching is not allowed. However, if the qualifying type is
10535 -- specific and the expression has a class-wide type, it may still be
10536 -- okay, since it can be the result of the expansion of a call to a
10537 -- dispatching function, so we also have to check class-wideness of the
10538 -- type of the expression's original node.
10541 or else
10545 then
10549 -- If the target type is unconstrained, then we reset the type of the
10550 -- result from the type of the expression. For other cases, the actual
10551 -- subtype of the expression is the target type. But we avoid doing it
10552 -- for an allocator since this is not needed and might be problematic.
10557 then
10564 -- If we still have a qualified expression after the static evaluation,
10565 -- then apply a scalar range check if needed. The reason that we do this
10566 -- after the Eval call is that otherwise, the application of the range
10567 -- check may convert an illegal static expression and result in warning
10568 -- rather than giving an error (e.g Integer'(Integer'Last + 1)).
10572 then
10576 -- AI12-0100: Once the qualified expression is resolved, check whether
10577 -- operand statisfies a static predicate of the target subtype, if any.
10578 -- In the static expression case, a predicate check failure is an error.
10581 Check_Expression_Against_Static_Predicate
10586 ------------------------------
10587 -- Resolve_Raise_Expression --
10588 ------------------------------
10591 begin
10596 else
10599 -- Apply check for required parentheses in the enclosing
10600 -- context of raise_expressions (RM 11.3 (2)), including default
10601 -- expressions in contexts that can include aspect specifications,
10602 -- and ancestor parts of extension aggregates.
10604 declare
10608 begin
10611 loop
10618 then
10625 if not Parentheses_Found
10627 and then
10629 | N_Floating_Point_Definition
10630 | N_Ordinary_Fixed_Point_Definition
10631 | N_Decimal_Fixed_Point_Definition
10632 | N_Extension_Aggregate
10633 | N_Discriminant_Specification
10634 | N_Parameter_Specification
10635 | N_Formal_Object_Declaration)
10638 and then
10640 then
10641 Error_Msg_N
10643 N);
10649 -------------------
10650 -- Resolve_Range --
10651 -------------------
10658 -- Returns True if N is of the form X'First .. X'Last where X is the
10659 -- same entity for both attributes.
10661 --------------------
10662 -- First_Last_Ref --
10663 --------------------
10669 begin
10674 then
10675 declare
10678 begin
10688 -- Start of processing for Resolve_Range
10690 begin
10696 -- Reanalyze the lower bound after both bounds have been analyzed, so
10697 -- that the range is known to be static or not by now. This may trigger
10698 -- more compile-time evaluation, which is useful for static analysis
10699 -- with GNATprove. This is not needed for compilation or static analysis
10700 -- with CodePeer, as full expansion does that evaluation then.
10707 -- Check for inappropriate range on unordered enumeration type
10711 -- Exclude X'First .. X'Last if X is the same entity for both
10713 and then not First_Last_Ref
10714 then
10716 Error_Msg_NE
10723 -- We have to check the bounds for being within the base range as
10724 -- required for a non-static context. Normally this is automatic and
10725 -- done as part of evaluating expressions, but the N_Range node is an
10726 -- exception, since in GNAT we consider this node to be a subexpression,
10727 -- even though in Ada it is not. The circuit in Sem_Eval could check for
10728 -- this, but that would put the test on the main evaluation path for
10729 -- expressions.
10734 -- Check for an ambiguous range over character literals. This will
10735 -- happen with a membership test involving only literals.
10743 -- If bounds are static, constant-fold them, so size computations are
10744 -- identical between front-end and back-end. Do not perform this
10745 -- transformation while analyzing generic units, as type information
10746 -- would be lost when reanalyzing the constant node in the instance.
10759 --------------------------
10760 -- Resolve_Real_Literal --
10761 --------------------------
10766 begin
10767 -- Special processing for fixed-point literals to make sure that the
10768 -- value is an exact multiple of the small where this is required. We
10769 -- skip this for the universal real case, and also for generic types.
10775 then
10776 -- We must freeze the base type to get the proper value of the small
10782 declare
10789 begin
10790 -- Case of literal is not an exact multiple of the Small
10794 -- For a source program literal for a decimal fixed-point type,
10795 -- this is statically illegal (RM 4.9(36)).
10800 then
10804 -- Generate a warning if literal from source
10807 and then Warn_On_Bad_Fixed_Value
10808 then
10809 Error_Msg_N
10811 N);
10814 -- Replace literal by a value that is the exact representation
10815 -- of a value of the type, i.e. a multiple of the small value,
10816 -- by truncation, since Machine_Rounds is false for all GNAT
10817 -- fixed-point types (RM 4.9(38)).
10827 -- In all cases, set the corresponding integer field
10833 -- Now replace the actual type by the expected type as usual
10839 -----------------------
10840 -- Resolve_Reference --
10841 -----------------------
10846 begin
10847 -- Replace general access with specific type
10855 -- If we are taking the reference of a volatile entity, then treat it as
10856 -- a potential modification of this entity. This is too conservative,
10857 -- but necessary because remove side effects can cause transformations
10858 -- of normal assignments into reference sequences that otherwise fail to
10859 -- notice the modification.
10866 --------------------------------
10867 -- Resolve_Selected_Component --
10868 --------------------------------
10883 -- Check whether this is the initialization of a component within an
10884 -- init proc (by assignment or call to another init proc). If true,
10885 -- there is no need for a discriminant check.
10887 --------------------
10888 -- Init_Component --
10889 --------------------
10892 begin
10893 return Inside_Init_Proc
10899 -- Start of processing for Resolve_Selected_Component
10901 begin
10904 -- Use the context type to select the prefix that has a selector
10905 -- of the correct name and type.
10913 else
10917 -- Locate selected component. For a private prefix the selector
10918 -- can denote a discriminant.
10922 -- The visible components of a class-wide type are those of
10923 -- the root type.
10933 then
10940 else
10944 Error_Msg_N
10949 else
10952 -- There may be an implicit dereference. Retrieve
10953 -- designated record type.
10957 else
10963 -- Resolution chooses the new interpretation.
10964 -- Find the component with the right name.
10969 loop
10986 -- There must be a legal interpretation at this point
10991 -- In general the expected type is the type of the context, not the
10992 -- type of the candidate selected component.
10997 -- The type of the context and that of the component are
10998 -- compatible and in general identical, but if they are anonymous
10999 -- access-to-subprogram types, the relevant type is that of the
11000 -- component. This matters in Unnest_Subprograms mode, where the
11001 -- relevant context is the one in which the type is declared, not
11002 -- the point of use. This determines what activation record to use.
11007 -- When the type of the component is an access to a class-wide type
11008 -- the relevant type is that of the component (since in such case we
11009 -- may need to generate implicit type conversions or dispatching
11010 -- calls).
11015 then
11019 else
11020 -- Resolve prefix with its type
11025 -- Generate cross-reference. We needed to wait until full overloading
11026 -- resolution was complete to do this, since otherwise we can't tell if
11027 -- we are an lvalue or not.
11031 else
11035 -- If the prefix's type is an access type, get to the real record type.
11036 -- Note: we do not apply an access check because an explicit dereference
11037 -- will be introduced later, and the check will happen there.
11043 else
11046 -- If the prefix is an entity it may have a deferred reference set
11047 -- during analysis of the selected component. After resolution we
11048 -- can transform it into a proper reference. This prevents spurious
11049 -- warnings on useless assignments when the same selected component
11050 -- is the actual for an out parameter in a subsequent call.
11054 then
11057 else
11063 -- Set flag for expander if discriminant check required on a component
11064 -- appearing within a variant.
11070 and then
11073 and then not Init_Component
11074 then
11082 -- If the prefix is a record conversion, this may be a renamed
11083 -- discriminant whose bounds differ from those of the original
11084 -- one, so we must ensure that a range check is performed.
11089 then
11093 -- Eval_Selected_Component may e.g. fold statically known discriminants.
11099 -- If the record type is atomic and the component is not, then this
11100 -- is worth a warning before Ada 2022, since we have a situation
11101 -- where the access to the component may cause extra read/writes of
11102 -- the atomic object, or partial word accesses, both of which may be
11103 -- unexpected.
11109 then
11110 Error_Msg_N
11113 Error_Msg_N
11123 -------------------
11124 -- Resolve_Shift --
11125 -------------------
11132 begin
11133 -- We do the resolution using the base type, because intermediate values
11134 -- in expressions always are of the base type, not a subtype of it.
11147 ---------------------------
11148 -- Resolve_Short_Circuit --
11149 ---------------------------
11156 begin
11157 -- Ensure all actions associated with the left operand (e.g.
11158 -- finalization of transient objects) are fully evaluated locally within
11159 -- an expression with actions. This is particularly helpful for coverage
11160 -- analysis. However this should not happen in generics or if option
11161 -- Minimize_Expression_With_Actions is set.
11164 declare
11166 begin
11174 -- Set Comes_From_Source on L to preserve warnings for unset
11175 -- reference.
11184 -- Check for issuing warning for always False assert/check, this happens
11185 -- when assertions are turned off, in which case the pragma Assert/Check
11186 -- was transformed into:
11188 -- if False and then <condition> then ...
11190 -- and we detect this pattern
11192 if Warn_On_Assertion_Failure
11199 then
11200 declare
11203 begin
11204 -- Special handling of Asssert pragma
11208 then
11209 declare
11211 Original_Node
11212 (Expression
11215 begin
11216 -- Don't warn if original condition is explicit False,
11217 -- since obviously the failure is expected in this case.
11221 then
11224 -- Issue warning. We do not want the deletion of the
11225 -- IF/AND-THEN to take this message with it. We achieve this
11226 -- by making sure that the expanded code points to the Sloc
11227 -- of the expression, not the original pragma.
11229 else
11230 -- Note: Use Error_Msg_F here rather than Error_Msg_N.
11231 -- The source location of the expression is not usually
11232 -- the best choice here. For example, it gets located on
11233 -- the last AND keyword in a chain of boolean expressiond
11234 -- AND'ed together. It is best to put the message on the
11235 -- first character of the assertion, which is the effect
11236 -- of the First_Node call here.
11238 Error_Msg_F
11240 Expression
11245 -- Similar processing for Check pragma
11249 then
11250 -- Don't want to warn if original condition is explicit False
11252 declare
11254 Original_Node
11255 (Expression
11257 begin
11260 then
11263 -- Post warning
11265 else
11266 -- Again use Error_Msg_F rather than Error_Msg_N, see
11267 -- comment above for an explanation of why we do this.
11269 Error_Msg_F
11271 Expression
11279 -- Continue with processing of short circuit
11288 -------------------
11289 -- Resolve_Slice --
11290 -------------------
11299 begin
11302 -- Use the context type to select the prefix that yields the correct
11303 -- array type.
11305 declare
11311 begin
11319 then
11327 else
11332 else
11343 else
11349 -- If the prefix's type is an access type, get to the real array type.
11350 -- Note: we do not apply an access check because an explicit dereference
11351 -- will be introduced later, and the check will happen there.
11356 -- If the prefix is an access to an unconstrained array, we must use
11357 -- the actual subtype of the object to perform the index checks. The
11358 -- object denoted by the prefix is implicit in the node, so we build
11359 -- an explicit representation for it in order to compute the actual
11360 -- subtype.
11365 declare
11369 begin
11376 -- In CodePeer mode the attribute Image is not expanded, so when it
11377 -- acts as a prefix of a slice, we handle it like a call to function
11378 -- returning an unconstrained string. Same for the Wide variants of
11379 -- attribute Image.
11388 | Name_Wide_Image
11389 | Name_Wide_Wide_Image)
11390 then
11393 -- If the name is a selected component that depends on discriminants,
11394 -- build an actual subtype for it. This can happen only when the name
11395 -- itself is overloaded; otherwise the actual subtype is created when
11396 -- the selected component is analyzed.
11399 and then Full_Analysis
11401 then
11402 declare
11405 begin
11410 -- Maybe this should just be "else", instead of checking for the
11411 -- specific case of slice??? This is needed for the case where the
11412 -- prefix is an Image attribute, which gets expanded to a slice, and so
11413 -- has a constrained subtype which we want to use for the slice range
11414 -- check applied below (the range check won't get done if the
11415 -- unconstrained subtype of the 'Image is used).
11421 -- Obtain the type of the array index
11425 else
11429 -- If name was overloaded, set slice type correctly now
11433 -- Handle the generation of a range check that compares the array index
11434 -- against the discrete_range. The check is not applied to internally
11435 -- built nodes associated with the expansion of dispatch tables. Check
11436 -- that Ada.Tags has already been loaded to avoid extra dependencies on
11437 -- the unit.
11439 if Tagged_Type_Expansion
11445 then
11448 -- The discrete_range is specified by a subtype name. Create an
11449 -- equivalent range attribute, apply checks to this attribute, but
11450 -- insert them into the range expression of the slice itself.
11453 Dexpr :=
11454 Make_Attribute_Reference
11456 Prefix =>
11465 -- The discrete_range is a regular range (or a range attribute, which
11466 -- will be resolved into a regular range). Resolve the bounds and remove
11467 -- their side effects.
11469 else
11486 -- Check bad use of type with predicates
11488 declare
11491 begin
11494 then
11496 else
11501 Bad_Predicated_Subtype_Use
11506 -- Otherwise here is where we check suspicious indexes
11518 ----------------------------
11519 -- Resolve_String_Literal --
11520 ----------------------------
11531 begin
11532 -- For a string appearing in a concatenation, defer creation of the
11533 -- string_literal_subtype until the end of the resolution of the
11534 -- concatenation, because the literal may be constant-folded away. This
11535 -- is a useful optimization for long concatenation expressions.
11537 -- If the string is an aggregate built for a single character (which
11538 -- happens in a non-static context) or a is null string to which special
11539 -- checks may apply, we build the subtype. Wide strings must also get a
11540 -- string subtype if they come from a one character aggregate. Strings
11541 -- generated by attributes might be static, but it is often hard to
11542 -- determine whether the enclosing context is static, so we generate
11543 -- subtypes for them as well, thus losing some rarer optimizations ???
11544 -- Same for strings that come from a static conversion.
11546 Need_Check :=
11555 -- If the resolving type is itself a string literal subtype, we can just
11556 -- reuse it, since there is no point in creating another.
11562 and then not Need_Check
11564 | N_Attribute_Reference
11565 | N_Qualified_Expression
11566 | N_Type_Conversion
11567 then
11570 -- Do not generate a string literal subtype for the default expression
11571 -- of a formal parameter in GNATprove mode. This is because the string
11572 -- subtype is associated with the freezing actions of the subprogram,
11573 -- however freezing is disabled in GNATprove mode and as a result the
11574 -- subtype is unavailable.
11576 elsif GNATprove_Mode
11578 then
11581 -- Otherwise we must create a string literal subtype. Note that the
11582 -- whole idea of string literal subtypes is simply to avoid the need
11583 -- for building a full fledged array subtype for each literal.
11585 else
11591 or else Need_Check
11592 then
11599 then
11605 -- The validity of a null string has been checked in the call to
11606 -- Eval_String_Literal.
11611 -- Always accept string literal with component type Any_Character, which
11612 -- occurs in error situations and in comparisons of literals, both of
11613 -- which should accept all literals.
11618 -- If the type is bit-packed, then we always transform the string
11619 -- literal into a full fledged aggregate.
11624 -- Deal with cases of Wide_Wide_String, Wide_String, and String
11626 else
11627 -- For Standard.Wide_Wide_String, or any other type whose component
11628 -- type is Standard.Wide_Wide_Character, we know that all the
11629 -- characters in the string must be acceptable, since the parser
11630 -- accepted the characters as valid character literals.
11635 -- For the case of Standard.String, or any other type whose component
11636 -- type is Standard.Character, we must make sure that there are no
11637 -- wide characters in the string, i.e. that it is entirely composed
11638 -- of characters in range of type Character.
11640 -- If the string literal is the result of a static concatenation, the
11641 -- test has already been performed on the components, and need not be
11642 -- repeated.
11646 then
11650 -- If we are out of range, post error. This is one of the
11651 -- very few places that we place the flag in the middle of
11652 -- a token, right under the offending wide character. Not
11653 -- quite clear if this is right wrt wide character encoding
11654 -- sequences, but it's only an error message.
11656 Error_Msg
11663 -- For the case of Standard.Wide_String, or any other type whose
11664 -- component type is Standard.Wide_Character, we must make sure that
11665 -- there are no wide characters in the string, i.e. that it is
11666 -- entirely composed of characters in range of type Wide_Character.
11668 -- If the string literal is the result of a static concatenation,
11669 -- the test has already been performed on the components, and need
11670 -- not be repeated.
11674 then
11678 -- If we are out of range, post error. This is one of the
11679 -- very few places that we place the flag in the middle of
11680 -- a token, right under the offending wide character.
11682 -- This is not quite right, because characters in general
11683 -- will take more than one character position ???
11685 Error_Msg
11692 -- If the root type is not a standard character, then we will convert
11693 -- the string into an aggregate and will let the aggregate code do
11694 -- the checking. Standard Wide_Wide_Character is also OK here.
11696 else
11700 -- See if the component type of the array corresponding to the string
11701 -- has compile time known bounds. If yes we can directly check
11702 -- whether the evaluation of the string will raise constraint error.
11703 -- Otherwise we need to transform the string literal into the
11704 -- corresponding character aggregate and let the aggregate code do
11705 -- the checking. We use the same transformation if the component
11706 -- type has a static predicate, which will be applied to each
11707 -- character when the aggregate is resolved.
11711 -- Check for the case of full range, where we are definitely OK
11717 -- Here the range is not the complete base type range, so check
11719 declare
11727 begin
11730 then
11736 then
11737 Apply_Compile_Time_Constraint_Error
11739 CE_Range_Check_Failed,
11752 -- If we got here we meed to transform the string literal into the
11753 -- equivalent qualified positional array aggregate. This is rather
11754 -- heavy artillery for this situation, but it is hard work to avoid.
11756 declare
11761 begin
11762 -- Build the character literals, we give them source locations that
11763 -- correspond to the string positions, which is a bit tricky given
11764 -- the possible presence of wide character escape sequences.
11778 -- Should we have a call to Skip_Wide here ???
11780 -- ??? else
11781 -- Skip_Wide (P);
11789 Expression =>
11796 -------------------------
11797 -- Resolve_Target_Name --
11798 -------------------------
11801 begin
11805 -----------------------------
11806 -- Resolve_Type_Conversion --
11807 -----------------------------
11819 -- Set to False to suppress cases where we want to suppress the test
11820 -- for redundancy to avoid possible false positives on this warning.
11822 begin
11823 if not Conv_OK
11825 then
11829 -- If the Operand Etype is Universal_Fixed, then the conversion is
11830 -- never redundant. We need this check because by the time we have
11831 -- finished the rather complex transformation, the conversion looks
11832 -- redundant when it is not.
11837 -- If the operand is marked as Any_Fixed, then special processing is
11838 -- required. This is also a case where we suppress the test for a
11839 -- redundant conversion, since most certainly it is not redundant.
11844 -- Mixed-mode operation involving a literal. Context must be a fixed
11845 -- type which is applied to the literal subsequently.
11847 -- Multiplication and division involving two fixed type operands must
11848 -- yield a universal real because the result is computed in arbitrary
11849 -- precision.
11855 then
11861 or else
11863 then
11864 -- Return if expression is ambiguous
11869 -- If nothing else, the available fixed type is Duration
11871 else
11875 -- Resolve the real operand with largest available precision
11879 else
11885 -- If the operand is a literal (it could be a non-static and
11886 -- illegal exponentiation) check whether the use of Duration
11887 -- is potentially inaccurate.
11892 then
11893 Error_Msg_N
11896 Error_Msg_N
11903 then
11906 else
11917 -- Note: we do the Eval_Type_Conversion call before applying the
11918 -- required checks for a subtype conversion. This is important, since
11919 -- both are prepared under certain circumstances to change the type
11920 -- conversion to a constraint error node, but in the case of
11921 -- Eval_Type_Conversion this may reflect an illegality in the static
11922 -- case, and we would miss the illegality (getting only a warning
11923 -- message), if we applied the type conversion checks first.
11927 -- Even when evaluation is not possible, we may be able to simplify the
11928 -- conversion or its expression. This needs to be done before applying
11929 -- checks, since otherwise the checks may use the original expression
11930 -- and defeat the simplifications. This is specifically the case for
11931 -- elimination of the floating-point Truncation attribute in
11932 -- float-to-int conversions.
11936 -- If after evaluation we still have a type conversion, then we may need
11937 -- to apply checks required for a subtype conversion. But skip them if
11938 -- universal fixed operands are involved, since range checks are handled
11939 -- separately for these cases, after the expansion done by Exp_Fixd.
11945 then
11949 -- Issue warning for conversion of simple object to its own type. We
11950 -- have to test the original nodes, since they may have been rewritten
11951 -- by various optimizations.
11955 -- Here we test for a redundant conversion if the warning mode is
11956 -- active (and was not locally reset), and we have a type conversion
11957 -- from source not appearing in a generic instance.
11959 if Test_Redundant
11962 and then not In_Instance
11963 then
11967 -- If the node is part of a larger expression, the Target_Type
11968 -- may not be the original type of the node if the context is a
11969 -- condition. Recover original type to see if conversion is needed.
11973 then
11977 -- If we have an entity name, then give the warning if the entity
11978 -- is the right type, or if it is a loop parameter covered by the
11979 -- original type (that's needed because loop parameters have an
11980 -- odd subtype coming from the bounds).
11984 and then
11986 or else
11990 -- If not an entity, then type of expression must match
11993 then
11994 -- One more check, do not give warning if the analyzed conversion
11995 -- has an expression with non-static bounds, and the bounds of the
11996 -- target are static. This avoids junk warnings in cases where the
11997 -- conversion is necessary to establish staticness, for example in
11998 -- a case statement.
12002 then
12005 -- Finally, if this type conversion occurs in a context requiring
12006 -- a prefix, and the expression is a qualified expression then the
12007 -- type conversion is not redundant, since a qualified expression
12008 -- is not a prefix, whereas a type conversion is. For example, "X
12009 -- := T'(Funx(...)).Y;" is illegal because a selected component
12010 -- requires a prefix, but a type conversion makes it legal: "X :=
12011 -- T(T'(Funx(...))).Y;"
12013 -- In Ada 2012, a qualified expression is a name, so this idiom is
12014 -- no longer needed, but we still suppress the warning because it
12015 -- seems unfriendly for warnings to pop up when you switch to the
12016 -- newer language version.
12020 | N_Indexed_Component
12021 | N_Selected_Component
12022 | N_Slice
12023 | N_Explicit_Dereference
12024 then
12027 -- Never warn on conversion to Long_Long_Integer'Base since
12028 -- that is most likely an artifact of the extended overflow
12029 -- checking and comes from complex expanded code.
12034 -- Here we give the redundant conversion warning. If it is an
12035 -- entity, give the name of the entity in the message. If not,
12036 -- just mention the expression.
12038 else
12041 Error_Msg_NE -- CODEFIX
12044 else
12045 Error_Msg_NE
12053 -- Ada 2005 (AI-251): Handle class-wide interface type conversions.
12054 -- No need to perform any interface conversion if the type of the
12055 -- expression coincides with the target type.
12058 and then Expander_Active
12060 then
12061 declare
12065 begin
12066 -- If the type of the operand is a limited view, use nonlimited
12067 -- view when available. If it is a class-wide type, recover the
12068 -- class-wide type of the nonlimited view.
12072 then
12077 -- It seems that Non_Limited_View should also be applied for
12078 -- Target when it has a limited view, but that leads to missing
12079 -- error checks on interface conversions further below. ???
12084 -- If the type of the operand is a limited view, use nonlimited
12085 -- view when available. If it is a class-wide type, recover the
12086 -- class-wide type of the nonlimited view.
12090 then
12098 -- If the target type is a limited view, use nonlimited view
12099 -- when available.
12103 then
12111 -- Conversion from interface type
12113 -- It seems that it would be better for the error checks below
12114 -- to be performed as part of Validate_Conversion (and maybe some
12115 -- of the error checks above could be moved as well?). ???
12119 -- Ada 2005 (AI-217): Handle entities from limited views
12123 Error_Msg_NE -- CODEFIX
12126 Error_Msg_N
12128 N);
12131 and then not
12134 then
12136 Error_Msg_NE -- CODEFIX
12139 Error_Msg_N
12141 N);
12143 else
12147 -- Conversion to interface type
12151 -- Handle subtypes
12158 or else Interface_Present_In_Ancestor
12161 then
12163 else
12166 Error_Msg_N
12174 -- Ada 2012: Once the type conversion is resolved, check whether the
12175 -- operand statisfies a static predicate of the target subtype, if any.
12176 -- In the static expression case, a predicate check failure is an error.
12179 Check_Expression_Against_Static_Predicate
12183 -- If at this stage we have a fixed to integer conversion, make sure the
12184 -- Do_Range_Check flag is set, because such conversions in general need
12185 -- a range check. We only need this if expansion is off, see above why.
12188 and then not Expander_Active
12193 then
12197 -- Generating C code a type conversion of an access to constrained
12198 -- array type to access to unconstrained array type involves building
12199 -- a fat pointer which in general cannot be generated on the fly. We
12200 -- remove side effects in order to store the result of the conversion
12201 -- into a temporary.
12203 if Modify_Tree_For_C
12210 then
12215 ----------------------
12216 -- Resolve_Unary_Op --
12217 ----------------------
12226 begin
12227 -- Deal with intrinsic unary operators
12233 then
12238 -- Deal with universal cases
12247 -- Generate warning for negative literal of a modular type, unless it is
12248 -- enclosed directly in a type qualification or a type conversion, as it
12249 -- is likely not what the user intended. We don't issue the warning for
12250 -- the common use of -1 to denote OxFFFF_FFFF...
12252 if Warn_On_Suspicious_Modulus_Value
12257 | N_Type_Conversion
12259 then
12260 Error_Msg_N
12265 Error_Msg_N
12269 -- Generate warning for expressions like abs (x mod 2)
12271 if Warn_On_Redundant_Constructs
12273 then
12277 Error_Msg_N -- CODEFIX
12282 -- Deal with reference generation
12289 -- Set overflow checking bit. Much cleverer code needed here eventually
12290 -- and perhaps the Resolve routines should be separated for the various
12291 -- arithmetic operations, since they will need different processing ???
12299 -- Generate warning for expressions like -5 mod 3 for integers. No need
12300 -- to worry in the floating-point case, since parens do not affect the
12301 -- result so there is no point in giving in a warning.
12303 declare
12312 begin
12313 if Warn_On_Questionable_Missing_Parens
12317 then
12320 -- We are looking for cases where the right operand is not
12321 -- parenthesized, and is a binary operator, multiply, divide, or
12322 -- mod. These are the cases where the grouping can affect results.
12326 then
12327 -- For mod, we always give the warning, since the value is
12328 -- affected by the parenthesization (e.g. (-5) mod 315 /=
12329 -- -(5 mod 315)). But for the other cases, the only concern is
12330 -- overflow, e.g. for the case of 8 big signed (-(2 * 64)
12331 -- overflows, but (-2) * 64 does not). So we try to give the
12332 -- message only when overflow is possible.
12336 then
12341 else
12347 else
12351 -- Note that the test below is deliberately excluding the
12352 -- largest negative number, since that is a potentially
12353 -- troublesome case (e.g. -2 * x, where the result is the
12354 -- largest negative integer has an overflow with 2 * x).
12361 -- For the multiplication case, the only case we have to worry
12362 -- about is when (-a)*b is exactly the largest negative number
12363 -- so that -(a*b) can cause overflow. This can only happen if
12364 -- a is a power of 2, and more generally if any operand is a
12365 -- constant that is not a power of 2, then the parentheses
12366 -- cannot affect whether overflow occurs. We only bother to
12367 -- test the left most operand
12369 -- Loop looking at left operands for one that has known value
12376 -- Operand value of 0 or 1 skips warning
12381 -- Otherwise check power of 2, if power of 2, warn, if
12382 -- anything else, skip warning.
12384 else
12388 else
12397 -- Keep looking at left operands
12402 -- For rem or "/" we can only have a problematic situation
12403 -- if the divisor has a value of minus one or one. Otherwise
12404 -- overflow is impossible (divisor > 1) or we have a case of
12405 -- division by zero in any case.
12410 then
12414 -- If we fall through warning should be issued
12416 -- Shouldn't we test Warn_On_Questionable_Missing_Parens ???
12418 Error_Msg_N
12425 ----------------------------------
12426 -- Resolve_Unchecked_Expression --
12427 ----------------------------------
12429 procedure Resolve_Unchecked_Expression
12432 is
12433 begin
12438 ---------------------------------------
12439 -- Resolve_Unchecked_Type_Conversion --
12440 ---------------------------------------
12442 procedure Resolve_Unchecked_Type_Conversion
12445 is
12451 begin
12452 -- Resolve operand using its own type
12456 -- If the expression is a conversion to universal integer of an
12457 -- an expression with an integer type, then we can eliminate the
12458 -- intermediate conversion to universal integer.
12463 then
12468 -- In an inlined context, the unchecked conversion may be applied
12469 -- to a literal, in which case its type is the type of the context.
12470 -- (In other contexts conversions cannot apply to literals).
12472 if In_Inlined_Body
12476 then
12484 ------------------------------
12485 -- Rewrite_Operator_As_Call --
12486 ------------------------------
12493 begin
12500 New_N :=
12511 ------------------------------
12512 -- Rewrite_Renamed_Operator --
12513 ------------------------------
12515 procedure Rewrite_Renamed_Operator
12519 is
12524 begin
12525 -- Do not perform this transformation within a pre/postcondition,
12526 -- because the expression will be reanalyzed, and the transformation
12527 -- might affect the visibility of the operator, e.g. in an instance.
12528 -- Note that fully analyzed and expanded pre/postconditions appear as
12529 -- pragma Check equivalents.
12535 -- Likewise when an expression function is being preanalyzed, since the
12536 -- expression will be reanalyzed as part of the generated body.
12539 declare
12541 begin
12544 N_Expression_Function
12545 then
12551 -- Rewrite the operator node using the real operator, not its renaming.
12552 -- Exclude user-defined intrinsic operations of the same name, which are
12553 -- treated separately and rewritten as calls.
12562 -- Indicate that both the original entity and its renaming are
12563 -- referenced at this point.
12574 -- If the context type is private, add the appropriate conversions so
12575 -- that the operator is applied to the full view. This is done in the
12576 -- routines that resolve intrinsic operators.
12580 when N_Op_Add
12581 | N_Op_Divide
12582 | N_Op_Expon
12583 | N_Op_Mod
12584 | N_Op_Multiply
12585 | N_Op_Rem
12586 | N_Op_Subtract
12587 =>
12590 when N_Op_Abs
12591 | N_Op_Minus
12592 | N_Op_Plus
12593 =>
12603 -- Operator renames a user-defined operator of the same name. Use the
12604 -- original operator in the node, which is the one Gigi knows about.
12611 -----------------------
12612 -- Set_Slice_Subtype --
12613 -----------------------
12615 -- Build an implicit subtype declaration to represent the type delivered by
12616 -- the slice. This is an abbreviated version of an array subtype. We define
12617 -- an index subtype for the slice, using either the subtype name or the
12618 -- discrete range of the slice. To be consistent with index usage elsewhere
12619 -- we create a list header to hold the single index. This list is not
12620 -- otherwise attached to the syntax tree.
12631 begin
12637 else
12638 -- We force the evaluation of a range. This is definitely needed in
12639 -- the renamed case, and seems safer to do unconditionally. Note in
12640 -- any case that since we will create and insert an Itype referring
12641 -- to this range, we must make sure any side effect removal actions
12642 -- are inserted before the Itype definition.
12648 -- If the discrete range is given by a subtype indication, the
12649 -- type of the slice is the base of the subtype mark.
12652 declare
12654 begin
12663 -- Take a new copy of Drange (where bounds have been rewritten to
12664 -- reference side-effect-free names). Using a separate tree ensures
12665 -- that further expansion (e.g. while rewriting a slice assignment
12666 -- into a FOR loop) does not attempt to remove side effects on the
12667 -- bounds again (which would cause the bounds in the index subtype
12668 -- definition to refer to temporaries before they are defined) (the
12669 -- reason is that some names are considered side effect free here
12670 -- for the subtype, but not in the context of a loop iteration
12671 -- scheme).
12693 -- The Etype of the existing Slice node is reset to this slice subtype.
12694 -- Its bounds are obtained from its first index.
12698 -- For bit-packed slice subtypes, freeze immediately (except in the case
12699 -- of being in a "spec expression" where we never freeze when we first
12700 -- see the expression).
12705 -- For all other cases insert an itype reference in the slice's actions
12706 -- so that the itype is frozen at the proper place in the tree (i.e. at
12707 -- the point where actions for the slice are analyzed). Note that this
12708 -- is different from freezing the itype immediately, which might be
12709 -- premature (e.g. if the slice is within a transient scope). This needs
12710 -- to be done only if expansion is enabled.
12717 --------------------------------
12718 -- Set_String_Literal_Subtype --
12719 --------------------------------
12727 begin
12739 -- The low bound is set from the low bound of the corresponding index
12740 -- type. Note that we do not store the high bound in the string literal
12741 -- subtype, but it can be deduced if necessary from the length and the
12742 -- low bound.
12747 -- If the lower bound is not static we create a range for the string
12748 -- literal, using the index type and the known length of the literal.
12749 -- If the length is 1, then the upper bound is set to a mere copy of
12750 -- the lower bound; or else, if the index type is a signed integer,
12751 -- then the upper bound is computed as Low_Bound + L - 1; otherwise,
12752 -- the upper bound is computed as T'Val (T'Pos (Low_Bound) + L - 1).
12754 else
12755 declare
12765 begin
12770 High_Bound :=
12775 else
12776 High_Bound :=
12779 Prefix =>
12783 Left_Opnd =>
12786 Prefix =>
12788 Expressions =>
12790 Right_Opnd =>
12795 Set_String_Literal_Low_Bound
12798 else
12799 -- If the index type is an enumeration type, build bounds
12800 -- expression with attributes.
12802 Set_String_Literal_Low_Bound
12806 Prefix =>
12810 Analyze_And_Resolve
12813 -- Build bona fide subtype for the string, and wrap it in an
12814 -- unchecked conversion, because the back end expects the
12815 -- String_Literal_Subtype to have a static lower bound.
12817 Index_Subtype :=
12824 -- In this context, the Index_Type may already have a constraint,
12825 -- so use common base type on string subtype. The base type may
12826 -- be used when generating attributes of the string, for example
12827 -- in the context of a slice assignment.
12849 ------------------------------
12850 -- Simplify_Type_Conversion --
12851 ------------------------------
12854 begin
12856 declare
12861 begin
12862 -- Special processing if the conversion is the expression of a
12863 -- Rounding or Truncation attribute reference. In this case we
12864 -- replace:
12866 -- ityp (ftyp'Rounding (x)) or ityp (ftyp'Truncation (x))
12868 -- by
12870 -- ityp (x)
12872 -- with the Float_Truncate flag set to False or True respectively,
12873 -- which is more efficient. We reuse Rounding for Machine_Rounding
12874 -- as System.Fat_Gen, which is a permissible behavior.
12877 and then
12883 | Name_Machine_Rounding
12884 | Name_Truncation
12885 then
12886 declare
12889 begin
12895 -- Special processing for the conversion of an integer literal to
12896 -- a dynamic type: we first convert the literal to the root type
12897 -- and then convert the result to the target type, the goal being
12898 -- to avoid doing range checks in universal integer.
12904 then
12908 -- If the expression is a conversion to universal integer of an
12909 -- an expression with an integer type, then we can eliminate the
12910 -- intermediate conversion to universal integer.
12915 then
12923 ------------------------------
12924 -- Try_User_Defined_Literal --
12925 ------------------------------
12927 function Try_User_Defined_Literal
12930 is
12931 begin
12933 | N_Op_Rem | N_Op_Subtract
12934 then
12936 -- Both operands must have the same type as the context.
12937 -- (ignoring for now fixed-point and exponentiation ops).
12945 if
12947 then
12952 else
12957 -- For other operators the context does not impose a type on
12958 -- the operands, but their types must match.
12962 and then
12963 Has_Applicable_User_Defined_Literal
12965 then
12971 and then
12972 Has_Applicable_User_Defined_Literal
12974 then
12977 else
12982 and then
12984 then
12993 -----------------------------
12994 -- Unique_Fixed_Point_Type --
12995 -----------------------------
12999 -- Give error messages for true ambiguity. Messages are posted on node
13000 -- N, and entities T1, T2 are the possible interpretations.
13002 -----------------------
13003 -- Fixed_Point_Error --
13004 -----------------------
13007 begin
13013 -- Local variables
13021 -- Start of processing for Unique_Fixed_Point_Type
13023 begin
13024 -- The operations on Duration are visible, so Duration is always a
13025 -- possible interpretation.
13029 -- Look for fixed-point types in enclosing scopes
13038 then
13042 else
13053 -- Look for visible fixed type declarations in the context
13064 then
13068 else
13083 else
13084 -- When the context is a type conversion, issue the warning on the
13085 -- expression of the conversion because it is the actual operation.
13089 else
13093 Error_Msg_NE
13100 ----------------------
13101 -- Valid_Conversion --
13102 ----------------------
13104 function Valid_Conversion
13109 is
13114 function Conversion_Check
13117 -- Little routine to post Msg if Valid is False, returns Valid value
13120 -- If Report_Errs, then calls Errout.Error_Msg_N with its arguments
13122 procedure Conversion_Error_NE
13126 -- If Report_Errs, then calls Errout.Error_Msg_NE with its arguments
13129 -- Return True if expression is within an instance but is not in one of
13130 -- the actuals of the instantiation. Type conversions within an instance
13131 -- are not rechecked because type visbility may lead to spurious errors,
13132 -- but conversions in an actual for a formal object must be checked.
13134 function Is_Discrim_Of_Bad_Access_Conversion_Argument
13136 -- Implicit anonymous-to-named access type conversions are not allowed
13137 -- if the "statically deeper than" relationship does not apply to the
13138 -- type of the conversion operand. See RM 8.6(28.1) and AARM 8.6(28.d).
13139 -- We deal with most such cases elsewhere so that we can emit more
13140 -- specific error messages (e.g., if the operand is an access parameter
13141 -- or a saooaaat (stand-alone object of an anonymous access type)), but
13142 -- here is where we catch the case where the operand is an access
13143 -- discriminant selected from a dereference of another such "bad"
13144 -- conversion argument.
13146 function Valid_Tagged_Conversion
13149 -- Specifically test for validity of tagged conversions
13152 -- Check index and component conformance, and accessibility levels if
13153 -- the component types are anonymous access types (Ada 2005).
13155 ----------------------
13156 -- Conversion_Check --
13157 ----------------------
13159 function Conversion_Check
13162 is
13163 begin
13164 if not Valid
13166 -- A generic unit has already been analyzed and we have verified
13167 -- that a particular conversion is OK in that context. Since the
13168 -- instance is reanalyzed without relying on the relationships
13169 -- established during the analysis of the generic, it is possible
13170 -- to end up with inconsistent views of private types. Do not emit
13171 -- the error message in such cases. The rest of the machinery in
13172 -- Valid_Conversion still ensures the proper compatibility of
13173 -- target and operand types.
13175 and then not In_Instance_Code
13176 then
13183 ------------------------
13184 -- Conversion_Error_N --
13185 ------------------------
13188 begin
13194 -------------------------
13195 -- Conversion_Error_NE --
13196 -------------------------
13198 procedure Conversion_Error_NE
13202 is
13203 begin
13209 ----------------------
13210 -- In_Instance_Code --
13211 ----------------------
13216 begin
13220 else
13224 -- The expression is part of an actual object if it appears in
13225 -- the generated object declaration in the instance.
13229 then
13232 else
13233 exit when
13242 -- Otherwise the expression appears within the instantiated unit
13248 --------------------------------------------------
13249 -- Is_Discrim_Of_Bad_Access_Conversion_Argument --
13250 --------------------------------------------------
13252 function Is_Discrim_Of_Bad_Access_Conversion_Argument
13254 is
13260 begin
13272 -- return False if Expr not of form <prefix>.all.Some_Component
13276 then
13277 -- conditional expressions, declare expressions ???
13284 -- The "statically deeper relationship" does not apply
13285 -- to generic formal access types, so a prefix of such
13286 -- a type is a "bad" prefix.
13291 -- The "statically deeper relationship" does apply to
13292 -- any other named access type.
13301 -- The "statically deeper relationship" applies to some
13302 -- anonymous access types and not to others. Return
13303 -- True for the cases where it does not apply. Also check
13304 -- recursively for the
13305 -- <prefix>.all.Access_Discrim.all.Access_Discrim case,
13306 -- where the correct result depends on <prefix>.
13309 N_Procedure_Specification | -- access parameter
13310 N_Function_Specification | -- access parameter
13311 N_Object_Declaration -- saooaaat
13315 ----------------------------
13316 -- Valid_Array_Conversion --
13317 ----------------------------
13334 begin
13335 -- Error if wrong number of dimensions
13337 if
13339 then
13340 Conversion_Error_N
13344 -- Number of dimensions matches
13346 else
13347 -- Loop through indexes of the two arrays
13355 -- Error if index types are incompatible
13361 then
13362 Conversion_Error_N
13364 Operand);
13372 -- If component types have same base type, all set
13377 -- Here if base types of components are not the same. The only
13378 -- time this is allowed is if we have anonymous access types.
13380 -- The conversion of arrays of anonymous access types can lead
13381 -- to dangling pointers. AI-392 formalizes the accessibility
13382 -- checks that must be applied to such conversions to prevent
13383 -- out-of-scope references.
13386 E_Anonymous_Access_Type
13387 | E_Anonymous_Access_Subprogram_Type
13389 and then
13391 then
13394 then
13397 Conversion_Error_N
13407 -- Conversion not allowed because of accessibility levels
13409 else
13410 Conversion_Error_N
13416 else
13420 -- All other cases where component base types do not match
13422 else
13423 Conversion_Error_N
13425 Operand);
13429 -- Check that component subtypes statically match. For numeric
13430 -- types this means that both must be either constrained or
13431 -- unconstrained. For enumeration types the bounds must match.
13432 -- All of this is checked in Subtypes_Statically_Match.
13434 if not Subtypes_Statically_Match
13436 then
13437 Conversion_Error_N
13446 -----------------------------
13447 -- Valid_Tagged_Conversion --
13448 -----------------------------
13450 function Valid_Tagged_Conversion
13453 is
13454 begin
13455 -- Upward conversions are allowed (RM 4.6(22))
13459 then
13462 -- Downward conversion are allowed if the operand is class-wide
13463 -- (RM 4.6(23)).
13467 then
13472 then
13473 return
13477 -- Ada 2005 (AI-251): The conversion to/from interface types is
13478 -- always valid. The types involved may be class-wide (sub)types.
13482 then
13485 -- If the operand is a class-wide type obtained through a limited_
13486 -- with clause, and the context includes the nonlimited view, use
13487 -- it to determine whether the conversion is legal.
13493 then
13498 then
13501 else
13502 Conversion_Error_NE
13509 -- Start of processing for Valid_Conversion
13511 begin
13515 declare
13523 begin
13524 -- Remove procedure calls, which syntactically cannot appear in
13525 -- this context, but which cannot be removed by type checking,
13526 -- because the context does not impose a type.
13528 -- The node may be labelled overloaded, but still contain only one
13529 -- interpretation because others were discarded earlier. If this
13530 -- is the case, retain the single interpretation if legal.
13538 then
13539 -- More than one candidate interpretation is available
13547 -- When compiling for a system where Address is of a visible
13548 -- integer type, spurious ambiguities can be produced when
13549 -- arithmetic operations have a literal operand and return
13550 -- System.Address or a descendant of it. These ambiguities
13551 -- are usually resolved by the context, but for conversions
13552 -- there is no context type and the removal of the spurious
13553 -- operations must be done explicitly here.
13555 if not Address_Is_Private
13557 then
13582 Conversion_Error_N
13585 -- If the interpretation involves a standard operator, use
13586 -- the location of the type, which may be user-defined.
13590 else
13594 Conversion_Error_N -- CODEFIX
13599 else
13603 Conversion_Error_N -- CODEFIX
13615 -- Deal with conversion of integer type to address if the pragma
13616 -- Allow_Integer_Address is in effect. We convert the conversion to
13617 -- an unchecked conversion in this case and we are all done.
13625 -- If we are within a child unit, check whether the type of the
13626 -- expression has an ancestor in a parent unit, in which case it
13627 -- belongs to its derivation class even if the ancestor is private.
13628 -- See RM 7.3.1 (5.2/3).
13632 -- Numeric types
13636 -- A universal fixed expression can be converted to any numeric type
13641 -- Also no need to check when in an instance or inlined body, because
13642 -- the legality has been established when the template was analyzed.
13643 -- Furthermore, numeric conversions may occur where only a private
13644 -- view of the operand type is visible at the instantiation point.
13645 -- This results in a spurious error if we check that the operand type
13646 -- is a numeric type.
13648 -- Note: in a previous version of this unit, the following tests were
13649 -- applied only for generated code (Comes_From_Source set to False),
13650 -- but in fact the test is required for source code as well, since
13651 -- this situation can arise in source code.
13656 -- Otherwise we need the conversion check
13658 else
13659 return Conversion_Check
13661 or else
13667 -- Array types
13673 then
13674 Conversion_Error_N
13678 else
13682 -- Ada 2005 (AI-251): Internally generated conversions of access to
13683 -- interface types added to force the displacement of the pointer to
13684 -- reference the corresponding dispatch table.
13689 then
13692 -- Ada 2005 (AI-251): Anonymous access types where target references an
13693 -- interface type.
13697 E_General_Access_Type | E_Anonymous_Access_Type
13699 then
13700 -- Check the static accessibility rule of 4.6(17). Note that the
13701 -- check is not enforced when within an instance body, since the
13702 -- RM requires such cases to be caught at run time.
13704 -- If the operand is a rewriting of an allocator no check is needed
13705 -- because there are no accessibility issues.
13713 then
13714 -- In an instance, this is a run-time check, but one we know
13715 -- will fail, so generate an appropriate warning. The raise
13716 -- will be generated by Expand_N_Type_Conversion.
13720 Conversion_Error_N
13722 Operand);
13725 else
13726 Conversion_Error_N
13728 Operand);
13732 -- Special accessibility checks are needed in the case of access
13733 -- discriminants declared for a limited type.
13737 then
13738 -- When the operand is a selected access discriminant the check
13739 -- needs to be made against the level of the object denoted by
13740 -- the prefix of the selected name (Accessibility_Level handles
13741 -- checking the prefix of the operand for this case).
13744 and then Static_Accessibility_Level
13747 then
13748 -- In an instance, this is a run-time check, but one we know
13749 -- will fail, so generate an appropriate warning. The raise
13750 -- will be generated by Expand_N_Type_Conversion.
13754 Conversion_Error_N
13759 -- Real error if not in instance body
13761 else
13762 Conversion_Error_N
13769 -- The case of a reference to an access discriminant from
13770 -- within a limited type declaration (which will appear as
13771 -- a discriminal) is always illegal because the level of the
13772 -- discriminant is considered to be deeper than any (nameable)
13773 -- access type.
13777 and then
13780 then
13781 Conversion_Error_N
13783 Operand);
13791 -- General and anonymous access types
13794 E_General_Access_Type | E_Anonymous_Access_Type
13795 and then
13796 Conversion_Check
13798 and then
13800 E_Access_Subprogram_Type |
13801 E_Access_Protected_Subprogram_Type,
13803 then
13806 then
13807 Conversion_Error_N
13812 -- Check the static accessibility rule of 4.6(17). Note that the
13813 -- check is not enforced when within an instance body, since the RM
13814 -- requires such cases to be caught at run time.
13819 N_Object_Declaration
13820 then
13821 -- Ada 2012 (AI05-0149): Perform legality checking on implicit
13822 -- conversions from an anonymous access type to a named general
13823 -- access type. Such conversions are not allowed in the case of
13824 -- access parameters and stand-alone objects of an anonymous
13825 -- access type. The implicit conversion case is recognized by
13826 -- testing that Comes_From_Source is False and that it's been
13827 -- rewritten. The Comes_From_Source test isn't sufficient because
13828 -- nodes in inlined calls to predefined library routines can have
13829 -- Comes_From_Source set to False. (Is there a better way to test
13830 -- for implicit conversions???).
13831 --
13832 -- Do not treat a rewritten 'Old attribute reference like other
13833 -- rewrite substitutions. This makes a difference, for example,
13834 -- in the case where we are generating the expansion of a
13835 -- membership test of the form
13836 -- Saooaaat'Old in Named_Access_Type
13837 -- because in this case Valid_Conversion needs to return True
13838 -- (otherwise the expansion will be False - see the call site
13839 -- in exp_ch4.adb).
13847 then
13850 -- When applying restriction No_Dynamic_Accessibility_Check,
13851 -- implicit conversions are allowed when the operand type is
13852 -- not deeper than the target type.
13857 then
13858 Conversion_Error_N
13862 -- Implicit conversions aren't allowed for objects of an
13863 -- anonymous access type, since such objects have nonstatic
13864 -- levels in Ada 2012.
13867 = N_Object_Declaration
13868 then
13869 Conversion_Error_N
13874 -- Implicit conversions aren't allowed for anonymous access
13875 -- parameters. We exclude anonymous access results as well
13876 -- as universal_access "=".
13880 N_Function_Specification |
13881 N_Procedure_Specification
13883 then
13884 Conversion_Error_N
13889 -- Detect access discriminant values that are illegal
13890 -- implicit anonymous-to-named access conversion operands.
13893 then
13894 Conversion_Error_N
13899 -- In other cases, the level of the operand's type must be
13900 -- statically less deep than that of the target type, else
13901 -- implicit conversion is disallowed (by RM12-8.6(27.1/3)).
13905 then
13906 Conversion_Error_N
13913 -- Check if the operand is deeper than the target type, taking
13914 -- care to avoid the case where we are converting a result of a
13915 -- function returning an anonymous access type since the "master
13916 -- of the call" would be target type of the conversion unless
13917 -- the target type is anonymous access as well - see RM 3.10.2
13918 -- (10.3/3).
13920 -- Note that when the restriction No_Dynamic_Accessibility_Checks
13921 -- is in effect wei also want to proceed with the conversion check
13922 -- described above.
13927 /= N_Function_Specification
13931 -- Check we are not in a return value ???
13934 or else
13937 then
13938 -- In an instance, this is a run-time check, but one we know
13939 -- will fail, so generate an appropriate warning. The raise
13940 -- will be generated by Expand_N_Type_Conversion.
13944 Conversion_Error_N
13946 Operand);
13949 -- If not in an instance body, this is a real error
13951 else
13952 -- Avoid generation of spurious error message
13955 Conversion_Error_N
13957 Operand);
13963 -- Special accessibility checks are needed in the case of access
13964 -- discriminants declared for a limited type.
13968 then
13969 -- When the operand is a selected access discriminant the check
13970 -- needs to be made against the level of the object denoted by
13971 -- the prefix of the selected name (Accessibility_Level handles
13972 -- checking the prefix of the operand for this case).
13975 and then Static_Accessibility_Level
13978 then
13979 -- In an instance, this is a run-time check, but one we know
13980 -- will fail, so generate an appropriate warning. The raise
13981 -- will be generated by Expand_N_Type_Conversion.
13985 Conversion_Error_N
13990 -- If not in an instance body, this is a real error
13992 else
13993 Conversion_Error_N
14000 -- The case of a reference to an access discriminant from
14001 -- within a limited type declaration (which will appear as
14002 -- a discriminal) is always illegal because the level of the
14003 -- discriminant is considered to be deeper than any (nameable)
14004 -- access type.
14007 and then
14010 then
14011 Conversion_Error_N
14013 Operand);
14019 -- In the presence of limited_with clauses we have to use nonlimited
14020 -- views, if available.
14024 -- Helper function to handle limited views
14026 --------------------------
14027 -- Full_Designated_Type --
14028 --------------------------
14033 begin
14034 -- Handle the limited view of a type
14038 then
14040 else
14045 -- Local Declarations
14053 -- Start of processing for Check_Limited
14055 begin
14059 else
14061 Conversion_Error_NE
14066 -- Ada 2005 AI-384: legality rule is symmetric in both
14067 -- designated types. The conversion is legal (with possible
14068 -- constraint check) if either designated type is
14069 -- unconstrained.
14072 or else
14074 and then
14077 then
14078 -- Special case, if Value_Size has been used to make the
14079 -- sizes different, the conversion is not allowed even
14080 -- though the subtypes statically match.
14085 then
14086 Conversion_Error_NE
14089 Conversion_Error_NE
14094 -- Normal case where conversion is allowed
14096 else
14100 else
14101 Error_Msg_NE
14109 -- Access to subprogram types. If the operand is an access parameter,
14110 -- the type has a deeper accessibility that any master, and cannot be
14111 -- assigned. We must make an exception if the conversion is part of an
14112 -- assignment and the target is the return object of an extended return
14113 -- statement, because in that case the accessibility check takes place
14114 -- after the return.
14118 -- Note: this test of Opnd_Type is there to prevent entering this
14119 -- branch in the case of a remote access to subprogram type, which
14120 -- is internally represented as an E_Record_Type.
14123 then
14127 and then
14131 then
14132 Conversion_Error_N
14134 Operand);
14135 Conversion_Error_N
14138 Operand);
14140 Error_Msg_NE
14145 -- Check that the designated types are subtype conformant
14151 -- Check the static accessibility rule of 4.6(20)
14155 then
14156 Conversion_Error_N
14158 Operand);
14160 -- Check that if the operand type is declared in a generic body,
14161 -- then the target type must be declared within that same body
14162 -- (enforces last sentence of 4.6(20)).
14165 declare
14171 begin
14178 Conversion_Error_N
14185 -- Check that the strub modes are compatible.
14186 -- We wish to reject explicit conversions only for
14187 -- incompatible modes.
14189 return Conversion_Check
14190 (Compatible_Strub_Modes
14195 -- Remote access to subprogram types
14199 then
14200 -- It is valid to convert from one RAS type to another provided
14201 -- that their specification statically match.
14203 -- Note: at this point, remote access to subprogram types have been
14204 -- expanded to their E_Record_Type representation, and we need to
14205 -- go back to the original access type definition using the
14206 -- Corresponding_Remote_Type attribute in order to check that the
14207 -- designated profiles match.
14212 Check_Subtype_Conformant
14215 Old_Id =>
14217 Err_Loc =>
14218 N);
14220 -- Check that the strub modes are compatible.
14221 -- We wish to reject explicit conversions only for
14222 -- incompatible modes.
14224 return Conversion_Check
14225 (Compatible_Strub_Modes
14230 -- If it was legal in the generic, it's legal in the instance
14235 -- If both are tagged types, check legality of view conversions
14238 and then
14240 then
14243 -- Types derived from the same root type are convertible
14248 -- In an instance or an inlined body, there may be inconsistent views of
14249 -- the same type, or of types derived from a common root.
14252 and then
14255 then
14258 -- Special check for common access type error case
14262 then
14264 Conversion_Error_NE -- CODEFIX
14268 -- Here we have a real conversion error
14270 else
14271 -- Check for missing regular with_clause when only a limited view of
14272 -- target is available.
14275 Conversion_Error_NE
14278 Conversion_Error_NE
14283 and then In_Package_Body
14284 then
14285 Conversion_Error_NE
14287 Conversion_Error_NE
14291 else
14292 Conversion_Error_NE