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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) 1992-2024, 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 ------------------------------------------------------------------------------
99 -----------------------
100 -- Local Subprograms --
101 -----------------------
103 -- Second pass (top-down) type checking and overload resolution procedures
104 -- Typ is the type required by context. These procedures propagate the
105 -- type information recursively to the descendants of N. If the node is not
106 -- overloaded, its Etype is established in the first pass. If overloaded,
107 -- the Resolve routines set the correct type. For arithmetic operators, the
108 -- Etype is the base type of the context.
110 -- Note that Resolve_Attribute is separated off in Sem_Attr
112 function Has_Applicable_User_Defined_Literal
115 -- Check whether N is a literal or a named number, and whether Typ has a
116 -- user-defined literal aspect that may apply to N. In this case, replace
117 -- N with a call to the corresponding function and return True.
120 -- Enforce the restrictions on the use of discriminants when constraining
121 -- a component of a discriminated type (record or concurrent type).
124 -- Given a node for an operator associated with type T, check that the
125 -- operator is visible. Operators all of whose operands are universal must
126 -- be checked for visibility during resolution because their type is not
127 -- determinable based on their operands.
129 procedure Check_Fully_Declared_Prefix
132 -- Check that the type of the prefix of a dereference is not incomplete
135 -- Given a call node, Call, which is known to occur immediately within the
136 -- subprogram being called, determines whether it is a detectable case of
137 -- an infinite recursion, and if so, outputs appropriate messages. Returns
138 -- True if an infinite recursion is detected, and False otherwise.
141 -- N is the node for a logical operator. If the operator is predefined, and
142 -- the root type of the operands is Standard.Boolean, then a check is made
143 -- for restriction No_Direct_Boolean_Operators. This procedure also handles
144 -- the style check for Style_Check_Boolean_And_Or.
147 -- N is either an indexed component or a selected component. This function
148 -- returns true if the prefix denotes an atomic object that has an address
149 -- clause (the case in which we may want to issue a warning).
152 -- Determine whether E is an access type declared by an access declaration,
153 -- and not an (anonymous) allocator type.
156 -- Utility to check whether the entity for an operator is a predefined
157 -- operator, in which case the expression is left as an operator in the
158 -- tree (else it is rewritten into a call). An instance of an intrinsic
159 -- conversion operation may be given an operator name, but is not treated
160 -- like an operator. Note that an operator that is an imported back-end
161 -- builtin has convention Intrinsic, but is expected to be rewritten into
162 -- a call, so such an operator is not treated as predefined by this
163 -- predicate.
165 procedure Preanalyze_And_Resolve
169 -- Subsidiary of public versions of Preanalyze_And_Resolve.
172 -- If a default expression in entry call N depends on the discriminants
173 -- of the task, it must be replaced with a reference to the discriminant
174 -- of the task being called.
176 procedure Resolve_Dependent_Expression
180 -- Internal procedure to resolve the dependent expression Expr of the
181 -- conditional expression N with type Typ.
183 procedure Resolve_Op_Concat_Arg
188 -- Internal procedure for Resolve_Op_Concat to resolve one operand of
189 -- concatenation operator. The operand is either of the array type or of
190 -- the component type. If the operand is an aggregate, and the component
191 -- type is composite, this is ambiguous if component type has aggregates.
194 -- Does the first part of the work of Resolve_Op_Concat
197 -- Does the "rest" of the work of Resolve_Op_Concat, after the left operand
198 -- has been resolved. See Resolve_Op_Concat for details.
215 procedure Resolve_Interpolated_String_Literal
241 function Operator_Kind
244 -- Utility to map the name of an operator into the corresponding Node. Used
245 -- by other node rewriting procedures.
248 -- Resolve actuals of call, and add default expressions for missing ones.
249 -- N is the Node_Id for the subprogram call, and Nam is the entity of the
250 -- called subprogram.
253 -- Called from Resolve_Call, when the prefix denotes an entry or element
254 -- of entry family. Actuals are resolved as for subprograms, and the node
255 -- is rebuilt as an entry call. Also called for protected operations. Typ
256 -- is the context type, which is used when the operation is a protected
257 -- function with no arguments, and the return value is indexed.
260 -- Called when P is the prefix of an indexed component, or of a selected
261 -- component, or of a slice. If P is of an access type, we unconditionally
262 -- rewrite it as an explicit dereference. This ensures that the expander
263 -- and the code generator have a fully explicit tree to work with.
266 -- A call to a user-defined intrinsic operator is rewritten as a call to
267 -- the corresponding predefined operator, with suitable conversions. Note
268 -- that this applies only for intrinsic operators that denote predefined
269 -- operators, not ones that are intrinsic imports of back-end builtins.
272 -- Ditto, for arithmetic unary operators
275 -- If an operator node resolves to a call to a user-defined operator,
276 -- rewrite the node as a function call.
278 procedure Make_Call_Into_Operator
282 -- Inverse transformation: if an operator is given in functional notation,
283 -- then after resolving the node, transform into an operator node, so that
284 -- operands are resolved properly. Recall that predefined operators do not
285 -- have a full signature and special resolution rules apply.
287 procedure Rewrite_Renamed_Operator
291 -- An operator can rename another, e.g. in an instantiation. In that
292 -- case, the proper operator node must be constructed and resolved.
295 -- The String_Literal_Subtype is built for all strings that are not
296 -- operands of a static concatenation operation. If the argument is not
297 -- a N_String_Literal node, then the call has no effect.
300 -- Build subtype of array type, with the range specified by the slice
303 -- Called after N has been resolved and evaluated, but before range checks
304 -- have been applied. This rewrites the conversion into a simpler form.
306 function Try_User_Defined_Literal
309 -- If the node is a literal or a named number or a conditional expression
310 -- whose dependent expressions are all literals or named numbers, and the
311 -- context type has a user-defined literal aspect, then rewrite the node
312 -- or its leaf nodes as calls to the corresponding function, which plays
313 -- the role of an implicit conversion.
315 function Try_User_Defined_Literal_For_Operator
318 -- If an operator node has a literal operand, check whether the type of the
319 -- context, or that of the other operand has a user-defined literal aspect
320 -- that can be applied to the literal to resolve the node. If such aspect
321 -- exists, replace literal with a call to the corresponding function and
322 -- return True, return false otherwise.
325 -- A universal_fixed expression in an universal context is unambiguous if
326 -- there is only one applicable fixed point type. Determining whether there
327 -- is only one requires a search over all visible entities, and happens
328 -- only in very pathological cases (see 6115-006).
330 -------------------------
331 -- Ambiguous_Character --
332 -------------------------
337 begin
341 -- First the ones in Standard
346 -- Include Wide_Wide_Character in Ada 2005 mode
352 -- Now any other types that match
362 -------------------------
363 -- Analyze_And_Resolve --
364 -------------------------
367 begin
373 begin
378 -- Versions with check(s) suppressed
380 procedure Analyze_And_Resolve
384 is
387 begin
389 declare
391 begin
397 else
398 declare
400 begin
408 and then Scope_Is_Transient
409 then
410 -- This can only happen if a transient scope was created for an inner
411 -- expression, which will be removed upon completion of the analysis
412 -- of an enclosing construct. The transient scope must have the
413 -- suppress status of the enclosing environment, not of this Analyze
414 -- call.
417 Scope_Suppress;
421 procedure Analyze_And_Resolve
424 is
427 begin
429 declare
431 begin
437 else
438 declare
440 begin
449 Scope_Suppress;
453 -------------------------------------
454 -- Has_Applicable_User_Defined_Literal --
455 -------------------------------------
457 function Has_Applicable_User_Defined_Literal
460 is
462 Literal_Aspect_Map :
483 begin
485 and then Present
487 or else
490 and then
491 Present
492 (Find_Aspect
494 then
495 Lit_Aspect :=
499 Callee :=
505 then
506 Callee :=
507 Corresponding_Primitive_Op
512 -- Handle an identifier that denotes a named number.
519 Start_String;
520 Store_String_Chars
525 else
527 Start_String;
533 Store_String_Chars
537 -- Note: Set_Etype is called below on Param1
540 Start_String;
541 Store_String_Chars
550 else
551 Error_Msg_NE
561 else
562 Param1 :=
563 Make_String_Literal
568 Call :=
569 Make_Function_Call
579 else
585 -- Conversion not needed if the result type of the call is class-wide
586 -- or if the result type matches the context type.
590 then
591 -- Conversion may be needed in case of an inherited
592 -- aspect of a derived type. For a null extension, we
593 -- use a null extension aggregate instead because the
594 -- downward type conversion would be illegal.
596 if Is_Null_Extension_Of
599 then
603 else
613 else
618 ----------------------------
619 -- Check_Discriminant_Use --
620 ----------------------------
628 begin
629 -- Any use in a spec-expression is legal
636 -- Discriminant cannot be used to constrain a scalar type
643 then
648 -- The following check catches the unusual case where a
649 -- discriminant appears within an index constraint that is part
650 -- of a larger expression within a constraint on a component,
651 -- e.g. "C : Int range 1 .. F (new A(1 .. D))". For now we only
652 -- check case of record components, and note that a similar check
653 -- should also apply in the case of discriminant constraints
654 -- below. ???
656 -- Note that the check for N_Subtype_Declaration below is to
657 -- detect the valid use of discriminants in the constraints of a
658 -- subtype declaration when this subtype declaration appears
659 -- inside the scope of a record type (which is syntactically
660 -- illegal, but which may be created as part of derived type
661 -- processing for records). See Sem_Ch3.Build_Derived_Record_Type
662 -- for more info.
666 and then not
668 and then
670 | N_Subtype_Declaration
672 then
673 Error_Msg_N
678 -- Detect a common error:
680 -- type R (D : Positive := 100) is record
681 -- Name : String (1 .. D);
682 -- end record;
684 -- The default value causes an object of type R to be allocated
685 -- with room for Positive'Last characters. The RM does not mandate
686 -- the allocation of the maximum size, but that is what GNAT does
687 -- so we should warn the programmer that there is a problem.
696 -- Return True if type T has a large enough range that any
697 -- array whose index type covered the whole range of the type
698 -- would likely raise Storage_Error.
700 ------------------------
701 -- Large_Storage_Type --
702 ------------------------
705 begin
706 -- The type is considered large if its bounds are known at
707 -- compile time and if it requires at least as many bits as
708 -- a Positive to store the possible values.
712 and then
717 -- Start of processing for Check_Large
719 begin
720 -- Check that the Disc has a large range
726 -- If the enclosing type is limited, we allocate only the
727 -- default value, not the maximum, and there is no need for
728 -- a warning.
734 -- Check that it is the high bound
738 then
742 -- Check the array allows a large range at this bound. First
743 -- find the array
757 -- Next, find the dimension
765 loop
774 -- Now, check the dimension has a large range
780 -- Warn about the danger
782 Error_Msg_N
792 -- Legal case is in index or discriminant constraint
795 | N_Discriminant_Association
796 then
798 Error_Msg_N
803 then
804 Error_Msg_N
810 -- Otherwise, context is an expression. It should not be within (i.e. a
811 -- subexpression of) a constraint for a component.
813 else
817 N_Component_Declaration | N_Subtype_Indication | N_Entry_Declaration
818 loop
824 -- If the discriminant is used in an expression that is a bound of a
825 -- scalar type, an Itype is created and the bounds are attached to
826 -- its range, not to the original subtype indication. Such use is of
827 -- course a double fault.
831 | N_Derived_Type_Definition
834 -- The constraint itself may be given by a subtype indication,
835 -- rather than by a more common discrete range.
838 and then
842 then
843 Error_Msg_N
849 --------------------------------
850 -- Check_For_Visible_Operator --
851 --------------------------------
854 begin
858 then
859 Error_Msg_NE -- CODEFIX
861 Error_Msg_N -- CODEFIX
866 ---------------------------------
867 -- Check_Fully_Declared_Prefix --
868 ---------------------------------
870 procedure Check_Fully_Declared_Prefix
873 is
874 begin
875 -- Check that the designated type of the prefix of a dereference is
876 -- not an incomplete type. This cannot be done unconditionally, because
877 -- dereferences of private types are legal in default expressions. This
878 -- case is taken care of in Check_Fully_Declared, called below. There
879 -- are also 2005 cases where it is legal for the prefix to be unfrozen.
881 -- This consideration also applies to similar checks for allocators,
882 -- qualified expressions, and type conversions.
884 -- An additional exception concerns other per-object expressions that
885 -- are not directly related to component declarations, in particular
886 -- representation pragmas for tasks. These will be per-object
887 -- expressions if they depend on discriminants or some global entity.
888 -- If the task has access discriminants, the designated type may be
889 -- incomplete at the point the expression is resolved. This resolution
890 -- takes place within the body of the initialization procedure, where
891 -- the discriminant is replaced by its discriminal.
895 then
898 -- Ada 2005 (AI-326): Tagged incomplete types allowed. The wrong usages
899 -- are handled by Analyze_Access_Attribute, Analyze_Assignment,
900 -- Analyze_Object_Renaming, and Freeze_Entity.
906 E_Incomplete_Type
908 then
910 else
915 ------------------------------
916 -- Check_Infinite_Recursion --
917 ------------------------------
921 -- Determine whether call N invokes the related enclosing subprogram
922 -- with actuals that differ from the subprogram's formals.
925 -- Determine whether arbitrary node N denotes a conditional construct
928 -- Determine whether arbitrary node N denotes a control flow statement
929 -- or a construct that may contains such a statement.
932 -- Determine whether arbitrary node N appears immediately within the
933 -- statements of an entry or subprogram body.
936 -- Determine whether arbitrary node N appears immediately within the
937 -- body of an entry or subprogram, and is preceded by a single raise
938 -- statement.
941 -- Determine whether arbitrary node N denotes a raise statement
944 -- Determine whether arbitrary node N is the sole source statement in
945 -- the body of the enclosing subprogram.
948 -- Determine whether arbitrary node N is preceded by a control flow
949 -- statement.
952 -- Determine whether arbitrary node N appears within a conditional
953 -- construct.
955 --------------------------------------
956 -- Invoked_With_Different_Arguments --
957 --------------------------------------
965 begin
966 -- Determine whether the formals of the invoked subprogram are not
967 -- used as actuals in the call.
973 -- The current actual does not match the current formal
977 then
988 ------------------------------
989 -- Is_Conditional_Statement --
990 ------------------------------
993 begin
994 return
996 | N_Case_Expression
997 | N_Case_Statement
998 | N_If_Expression
999 | N_If_Statement
1000 | N_Or_Else;
1003 -------------------------------
1004 -- Is_Control_Flow_Statement --
1005 -------------------------------
1008 begin
1009 -- It is assumed that all statements may affect the control flow in
1010 -- some way. A raise statement may be expanded into a non-statement
1011 -- node.
1016 --------------------------------
1017 -- Is_Immediately_Within_Body --
1018 --------------------------------
1023 begin
1024 return
1031 --------------------
1032 -- Is_Raise_Idiom --
1033 --------------------
1039 begin
1042 -- Assume that no raise statement has been seen yet
1046 -- Examine the statements preceding the input node, skipping
1047 -- internally-generated constructs.
1052 -- Multiple raise statements violate the idiom
1068 -- At this point the node must be preceded by a raise statement,
1069 -- and the raise statement has to be the sole statement within
1070 -- the enclosing entry or subprogram body.
1072 return
1079 ------------------------
1080 -- Is_Raise_Statement --
1081 ------------------------
1084 begin
1085 -- A raise statement may be transfomed into a Raise_xxx_Error node
1087 return
1092 -----------------------
1093 -- Is_Sole_Statement --
1094 -----------------------
1099 begin
1100 -- The input node appears within the statements of an entry or
1101 -- subprogram body. Examine the statements preceding the node.
1108 -- The statement is preceded by another statement or a source
1109 -- construct. This indicates that the node does not appear by
1110 -- itself.
1114 then
1124 -- The input node is within a construct nested inside the entry or
1125 -- subprogram body.
1130 ----------------------------------------
1131 -- Preceded_By_Control_Flow_Statement --
1132 ----------------------------------------
1134 function Preceded_By_Control_Flow_Statement
1136 is
1139 begin
1143 -- Examine the statements preceding the input node
1156 -- Assume that the node is part of some control flow statement
1161 ----------------------------------
1162 -- Within_Conditional_Statement --
1163 ----------------------------------
1168 begin
1174 -- Prevent the search from going too far
1186 -- Local variables
1191 -- Start of processing for Check_Infinite_Recursion
1193 begin
1194 -- The call is assumed to be safe when the enclosing subprogram is
1195 -- invoked with actuals other than its formals.
1196 --
1197 -- procedure Proc (F1 : ...; F2 : ...; ...; FN : ...) is
1198 -- begin
1199 -- ...
1200 -- Proc (A1, A2, ..., AN);
1201 -- ...
1202 -- end Proc;
1207 -- The call is assumed to be safe when the invocation of the enclosing
1208 -- subprogram depends on a conditional statement.
1209 --
1210 -- procedure Proc (F1 : ...; F2 : ...; ...; FN : ...) is
1211 -- begin
1212 -- ...
1213 -- if Some_Condition then
1214 -- Proc (F1, F2, ..., FN);
1215 -- end if;
1216 -- ...
1217 -- end Proc;
1222 -- The context of the call is assumed to be safe when the invocation of
1223 -- the enclosing subprogram is preceded by some control flow statement.
1224 --
1225 -- procedure Proc (F1 : ...; F2 : ...; ...; FN : ...) is
1226 -- begin
1227 -- ...
1228 -- if Some_Condition then
1229 -- ...
1230 -- end if;
1231 -- ...
1232 -- Proc (F1, F2, ..., FN);
1233 -- ...
1234 -- end Proc;
1239 -- Detect an idiom where the context of the call is preceded by a single
1240 -- raise statement.
1241 --
1242 -- procedure Proc (F1 : ...; F2 : ...; ...; FN : ...) is
1243 -- begin
1244 -- raise ...;
1245 -- Proc (F1, F2, ..., FN);
1246 -- end Proc;
1252 -- At this point it is certain that infinite recursion will take place
1253 -- as long as the call is executed. Detect a case where the context of
1254 -- the call is the sole source statement within the subprogram body.
1255 --
1256 -- procedure Proc (F1 : ...; F2 : ...; ...; FN : ...) is
1257 -- begin
1258 -- Proc (F1, F2, ..., FN);
1259 -- end Proc;
1260 --
1261 -- Install an explicit raise to prevent the infinite recursion.
1272 -- Otherwise infinite recursion could take place, considering other flow
1273 -- control constructs such as gotos, exit statements, etc.
1275 else
1284 ---------------------------------------
1285 -- Check_No_Direct_Boolean_Operators --
1286 ---------------------------------------
1289 begin
1292 then
1293 -- Restriction only applies to original source code
1300 -- Do style check (but skip if in instance, error is on template)
1309 ------------------------------
1310 -- Check_Parameterless_Call --
1311 ------------------------------
1317 -- If the prefix is of an access_to_subprogram type, the node must be
1318 -- rewritten as a call. Ditto if the prefix is overloaded and all its
1319 -- interpretations are access to subprograms.
1321 ---------------------------
1322 -- Prefix_Is_Access_Subp --
1323 ---------------------------
1329 begin
1330 -- If the context is an attribute reference that can apply to
1331 -- functions, this is never a parameterless call (RM 4.1.4(6)).
1335 in Name_Address | Name_Code_Address | Name_Access
1336 then
1341 return
1344 else
1349 then
1360 -- Start of processing for Check_Parameterless_Call
1362 begin
1363 -- Defend against junk stuff if errors already detected
1370 then
1377 -- If the context expects a value, and the name is a procedure, this is
1378 -- most likely a missing 'Access. Don't try to resolve the parameterless
1379 -- call, error will be caught when the outer call is analyzed.
1384 and then
1386 | N_Function_Call
1387 | N_Procedure_Call_Statement
1388 then
1392 -- Rewrite as call if overloadable entity that is (or could be, in the
1393 -- overloaded case) a function call. If we know for sure that the entity
1394 -- is an enumeration literal, we do not rewrite it.
1396 -- If the entity is the name of an operator, it cannot be a call because
1397 -- operators cannot have default parameters. In this case, this must be
1398 -- a string whose contents coincide with an operator name. Set the kind
1399 -- of the node appropriately.
1407 -- Rewrite as call if it is an explicit dereference of an expression of
1408 -- a subprogram access type, and the subprogram type is not that of a
1409 -- procedure or entry.
1411 or else
1414 -- Rewrite as call if it is a selected component which is a function,
1415 -- this is the case of a call to a protected function (which may be
1416 -- overloaded with other protected operations).
1418 or else
1421 or else
1423 E_Entry | E_Procedure
1426 -- If one of the above three conditions is met, rewrite as call. Apply
1427 -- the rewriting only once.
1429 then
1432 then
1434 -- This may be a prefixed call that was not fully analyzed, e.g.
1435 -- an actual in an instance.
1440 then
1448 -- The node is the name of the parameterless call. Preserve its
1449 -- descendants, which may be complex expressions.
1453 -- If overloaded, overload set belongs to new copy
1457 -- Change node to parameterless function call (note that the
1458 -- Parameter_Associations associations field is left set to Empty,
1459 -- its normal default value since there are no parameters)
1479 --------------------------------
1480 -- Is_Atomic_Ref_With_Address --
1481 --------------------------------
1486 begin
1490 else
1491 declare
1494 begin
1502 -----------------------------
1503 -- Is_Definite_Access_Type --
1504 -----------------------------
1508 begin
1514 ----------------------
1515 -- Is_Predefined_Op --
1516 ----------------------
1519 begin
1520 -- Predefined operators are intrinsic subprograms
1526 -- A call to a back-end builtin is never a predefined operator
1537 -----------------------------
1538 -- Make_Call_Into_Operator --
1539 -----------------------------
1541 procedure Make_Call_Into_Operator
1545 is
1560 -- If the operand is not universal, and the operator is given by an
1561 -- expanded name, verify that the operand has an interpretation with a
1562 -- type defined in the given scope of the operator.
1565 -- Find a type of the given class in package Pack that contains the
1566 -- operator.
1568 ---------------------------
1569 -- Operand_Type_In_Scope --
1570 ---------------------------
1577 begin
1581 else
1595 ---------------
1596 -- Type_In_P --
1597 ---------------
1603 -- Verify that node is not part of the type declaration for the
1604 -- candidate type, which would otherwise be invisible.
1606 -------------
1607 -- In_Decl --
1608 -------------
1614 begin
1623 else
1626 loop
1629 else
1638 -- Start of processing for Type_In_P
1640 begin
1641 -- If the context type is declared in the prefix package, this is the
1642 -- desired base type.
1647 else
1661 -- Start of processing for Make_Call_Into_Operator
1663 begin
1666 -- Preserve the Comes_From_Source flag on the result if the original
1667 -- call came from source. Although it is not strictly the case that the
1668 -- operator as such comes from the source, logically it corresponds
1669 -- exactly to the function call in the source, so it should be marked
1670 -- this way (e.g. to make sure that validity checks work fine).
1674 -- Ensure that the corresponding operator has the same parent as the
1675 -- original call. This guarantees that parent traversals performed by
1676 -- the ABE mechanism succeed.
1680 -- Binary operator
1690 -- Unary operator
1692 else
1698 -- If the operator is denoted by an expanded name, and the prefix is
1699 -- not Standard, but the operator is a predefined one whose scope is
1700 -- Standard, then this is an implicit_operator, inserted as an
1701 -- interpretation by the procedure of the same name. This procedure
1702 -- overestimates the presence of implicit operators, because it does
1703 -- not examine the type of the operands. Verify now that the operand
1704 -- type appears in the given scope. If right operand is universal,
1705 -- check the other operand. In the case of concatenation, either
1706 -- argument can be the component type, so check the type of the result.
1707 -- If both arguments are literals, look for a type of the right kind
1708 -- defined in the given scope. This elaborate nonsense is brought to
1709 -- you courtesy of b33302a. The type itself must be frozen, so we must
1710 -- find the type of the proper class in the given scope.
1712 -- A final wrinkle is the multiplication operator for fixed point types,
1713 -- which is defined in Standard only, and not in the scope of the
1714 -- fixed point type itself.
1719 -- If this is a package renaming, get renamed entity, which will be
1720 -- the scope of the operands if operaton is type-correct.
1726 -- If the entity being called is defined in the given package, it is
1727 -- a renaming of a predefined operator, and known to be legal.
1731 then
1734 -- Visibility does not need to be checked in an instance: if the
1735 -- operator was not visible in the generic it has been diagnosed
1736 -- already, else there is an implicit copy of it in the instance.
1744 then
1749 -- Ada 2005 AI-420: Predefined equality on Universal_Access is
1750 -- available.
1756 then
1759 else
1768 and then Is_Binary
1770 then
1776 -- Verify that the scope contains a type that corresponds to
1777 -- the given literal. Optimize the case where Pack is Standard.
1798 else
1807 else
1816 then
1819 -- If the type is defined elsewhere, and the operator is not
1820 -- defined in the given scope (by a renaming declaration, e.g.)
1821 -- then this is an error as well. If an extension of System is
1822 -- present, and the type may be defined there, Pack must be
1823 -- System itself.
1830 then
1833 else
1839 then
1846 Error_Msg_NE
1851 -- Detect a mismatch between the context type and the result type
1852 -- in the named package, which is otherwise not detected if the
1853 -- operands are universal. Check is only needed if source entity is
1854 -- an operator, not a function that renames an operator.
1861 and then not In_Instance
1862 then
1865 then
1866 -- Already checked above
1870 -- Operator may be defined in an extension of System
1875 then
1878 else
1879 -- Could we use Wrong_Type here??? (this would require setting
1880 -- Etype (N) to the actual type found where Typ was expected).
1891 else
1895 -- If this is a call to a function that renames a predefined equality,
1896 -- the renaming declaration provides a type that must be used to
1897 -- resolve the operands. This must be done now because resolution of
1898 -- the equality node will not resolve any remaining ambiguity, and it
1899 -- assumes that the first operand is not overloaded.
1904 then
1914 -- If this is an arithmetic operator and the result type is private,
1915 -- the operands and the result must be wrapped in conversion to
1916 -- expose the underlying numeric type and expand the proper checks,
1917 -- e.g. on division.
1921 when N_Op_Add
1922 | N_Op_Divide
1923 | N_Op_Expon
1924 | N_Op_Mod
1925 | N_Op_Multiply
1926 | N_Op_Rem
1927 | N_Op_Subtract
1928 =>
1931 when N_Op_Abs
1932 | N_Op_Minus
1933 | N_Op_Plus
1934 =>
1940 else
1945 -------------------
1946 -- Operator_Kind --
1947 -------------------
1949 function Operator_Kind
1952 is
1955 begin
1956 -- Use CASE statement or array???
1993 else
1997 -- Unary operators
1999 else
2008 else
2016 ----------------------------
2017 -- Preanalyze_And_Resolve --
2018 ----------------------------
2020 procedure Preanalyze_And_Resolve
2024 is
2028 Inside_Preanalysis_Without_Freezing;
2029 begin
2034 Inside_Preanalysis_Without_Freezing :=
2041 -- See also Preanalyze_And_Resolve in sem.adb for similar handling
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 GNATprove mode, most expansion is suppressed, and this
2050 -- later reanalysis and reexpansion may not occur. GNATprove mode does
2051 -- require the setting of checking flags for proof purposes, so we
2052 -- do the GNATprove 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.
2058 -- We also do not want to suppress checks if we are not dealing
2059 -- with a default expression. One such case that is known to reach
2060 -- this point is the expression of an expression function.
2064 else
2068 Expander_Mode_Restore;
2073 Inside_Preanalysis_Without_Freezing :=
2077 pragma Assert
2081 ----------------------------
2082 -- Preanalyze_And_Resolve --
2083 ----------------------------
2086 begin
2090 -- Version without context type
2095 begin
2102 Expander_Mode_Restore;
2106 ------------------------------------------
2107 -- Preanalyze_With_Freezing_And_Resolve --
2108 ------------------------------------------
2110 procedure Preanalyze_With_Freezing_And_Resolve
2113 is
2114 begin
2118 ----------------------------------
2119 -- Replace_Actual_Discriminants --
2120 ----------------------------------
2127 -- Comment needed???
2129 -------------------
2130 -- Process_Discr --
2131 -------------------
2136 begin
2142 then
2158 -- Start of processing for Replace_Actual_Discriminants
2160 begin
2164 -- Allow the replacement of concurrent discriminants in GNATprove even
2165 -- though this is a light expansion activity. Note that generic units
2166 -- are not modified.
2171 else
2187 -------------
2188 -- Resolve --
2189 -------------
2205 -- Determine whether a node comes from a predefined library unit or
2206 -- Standard.
2209 -- Try and fix up a literal so that it matches its expected type. New
2210 -- literals are manufactured if necessary to avoid cascaded errors.
2213 -- Additional diagnostics when an ambiguous call has an ambiguous
2214 -- argument (typically a controlling actual).
2217 -- Called when attempt at resolving current expression fails
2219 ------------------------------------
2220 -- Comes_From_Predefined_Lib_Unit --
2221 -------------------------------------
2224 begin
2225 return
2229 --------------------
2230 -- Patch_Up_Value --
2231 --------------------
2234 begin
2251 then
2256 Char_Literal_Value =>
2272 -------------------------------
2273 -- Report_Ambiguous_Argument --
2274 -------------------------------
2281 begin
2285 then
2288 -- Examine possible interpretations, and adapt the message
2289 -- for inherited subprograms declared by a type derivation.
2297 else
2305 -- Additional message and hint if the ambiguity involves an Ada 2022
2306 -- container aggregate.
2311 -----------------------
2312 -- Resolution_Failed --
2313 -----------------------
2316 begin
2319 -- Set the type to the desired one to minimize cascaded errors. Note
2320 -- that this is an approximation and does not work in all cases.
2327 -- The caller will return without calling the expander, so we need
2328 -- to set the analyzed flag. Note that it is fine to set Analyzed
2329 -- to True even if we are in the middle of a shallow analysis,
2330 -- (see the spec of sem for more details) since this is an error
2331 -- situation anyway, and there is no point in repeating the
2332 -- analysis later (indeed it won't work to repeat it later, since
2333 -- we haven't got a clear resolution of which entity is being
2334 -- referenced.)
2340 -- Start of processing for Resolve
2342 begin
2347 -- Access attribute on remote subprogram cannot be used for a non-remote
2348 -- access-to-subprogram type.
2352 | Name_Unrestricted_Access
2353 | Name_Unchecked_Access
2359 then
2360 Error_Msg_N
2364 -- If the context is a Remote_Access_To_Subprogram, access attributes
2365 -- must be resolved with the corresponding fat pointer. There is no need
2366 -- to check for the attribute name since the return type of an
2367 -- attribute is never a remote type.
2372 then
2373 declare
2381 begin
2382 -- Check that Typ is a remote access-to-subprogram type
2386 -- Prefix (N) must statically denote a remote subprogram
2387 -- declared in a package specification.
2391 Attr = Attribute_Unrestricted_Access
2392 then
2407 or else
2409 then
2411 Error_Msg_N
2413 N);
2416 -- If we are generating code in distributed mode, perform
2417 -- semantic checks against corresponding remote entities.
2419 if Expander_Active
2421 then
2422 Check_Subtype_Conformant
2424 Old_Id => Designated_Type
2450 then
2455 -- Return if already analyzed
2462 -- Any case of Any_Type as the Etype value means that we had a
2463 -- previous error.
2472 -- The resolution of an Expression_With_Actions is determined by
2473 -- its Expression, but if the node comes from source it is a
2474 -- Declare_Expression and requires scope management.
2479 else
2486 -- The resolution of a conditional expression that is the operand of a
2487 -- type conversion is determined by the conversion (RM 4.5.7(10/3)).
2491 then
2495 -- If not overloaded, then we know the type, and all that needs doing
2496 -- is to check that this type is compatible with the context. But note
2497 -- that we may have an operator with no interpretation in Ada 2022 for
2498 -- the case of possible user-defined literals as operands.
2504 else
2509 -- In the overloaded case, we must select the interpretation that
2510 -- is compatible with the context (i.e. the type passed to Resolve)
2512 else
2515 -- Loop through possible interpretations
2524 -- We are only interested in interpretations that are compatible
2525 -- with the expected type, any other interpretations are ignored.
2530 Write_Eol;
2533 else
2534 -- Skip the current interpretation if it is disabled by an
2535 -- abstract operator. This action is performed only when the
2536 -- type against which we are resolving is the same as the
2537 -- type of the interpretation.
2543 then
2551 -- First matching interpretation
2559 -- Matching interpretation that is not the first, maybe an
2560 -- error, but there are some cases where preference rules are
2561 -- used to choose between the two possibilities. These and
2562 -- some more obscure cases are handled in Disambiguate.
2564 else
2565 -- If the current statement is part of a predefined library
2566 -- unit, then all interpretations which come from user level
2567 -- packages should not be considered. Check previous and
2568 -- current one.
2576 -- Previous interpretation must be discarded
2586 -- Otherwise apply further disambiguation steps
2591 -- Disambiguation has succeeded. Skip the remaining
2592 -- interpretations.
2602 else
2603 -- Before we issue an ambiguity complaint, check for the
2604 -- case of a subprogram call where at least one of the
2605 -- arguments is Any_Type, and if so suppress the message,
2606 -- since it is a cascaded error. This can also happen for
2607 -- a generalized indexing operation.
2612 then
2613 declare
2617 begin
2633 Write_Eol;
2646 then
2651 then
2655 -- Not that special case, so issue message using the flag
2656 -- Ambiguous to control printing of the header message
2657 -- only at the start of an ambiguous set.
2662 then
2663 Error_Msg_N
2666 else
2667 Error_Msg_NE -- CODEFIX
2675 Error_Msg_N
2677 else
2678 Error_Msg_N -- CODEFIX
2684 then
2685 Report_Ambiguous_Argument;
2691 -- By default, the error message refers to the candidate
2692 -- interpretation. But if it is a predefined operator, it
2693 -- is implicitly declared at the declaration of the type
2694 -- of the operand. Recover the sloc of that declaration
2695 -- for the error message.
2701 Standard_Standard
2702 then
2707 then
2715 Standard_Standard
2716 then
2721 then
2725 -- If this is an indirect call, use the subprogram_type
2726 -- in the message, to have a meaningful location. Also
2727 -- indicate if this is an inherited operation, created
2728 -- by a type declaration.
2733 then
2735 Error_Msg_Sloc :=
2737 else
2744 then
2745 -- Special-case the message for universal_fixed
2746 -- operators, which are not declared with the type
2747 -- of the operand, but appear forever in Standard.
2751 then
2752 Error_Msg_N
2755 else
2756 Error_Msg_N
2760 elsif
2762 then
2763 Error_Msg_N
2765 else
2766 Error_Msg_N -- CODEFIX
2773 -- We have a matching interpretation, Expr_Type is the type
2774 -- from this interpretation, and Seen is the entity.
2776 -- For an operator, just set the entity name. The type will be
2777 -- set by the specific operator resolution routine.
2784 | N_Character_Literal
2785 | N_Delta_Aggregate
2786 | N_If_Expression
2787 then
2790 -- AI05-0139-2: Expression is overloaded because type has
2791 -- implicit dereference. The context may be the one that
2792 -- requires implicit dereferemce.
2798 -- If the expression is an entity, generate a reference
2799 -- to it, as this is not done for an overloaded construct
2800 -- during analysis.
2804 then
2807 -- Examine access discriminants of entity type,
2808 -- to check whether one of them yields the
2809 -- expected type.
2811 declare
2815 begin
2836 then
2837 -- If the node is a general indexing, the dereference is
2838 -- is inserted when resolving the rewritten form, else
2839 -- insert it now.
2843 then
2847 -- For an explicit dereference, attribute reference, range,
2848 -- short-circuit form (which is not an operator node), or call
2849 -- with a name that is an explicit dereference, there is
2850 -- nothing to be done at this point.
2853 | N_And_Then
2854 | N_Explicit_Dereference
2855 | N_Identifier
2856 | N_Indexed_Component
2857 | N_Or_Else
2858 | N_Range
2859 | N_Selected_Component
2860 | N_Slice
2862 then
2865 -- For procedure or function calls, set the type of the name,
2866 -- and also the entity pointer for the prefix.
2870 then
2877 then
2882 -- For all other cases, just set the type of the Name
2884 else
2892 -- Move to next interpretation
2900 -- At this stage Found indicates whether or not an acceptable
2901 -- interpretation exists. If not, then we have an error, except that if
2902 -- the context is Any_Type as a result of some other error, then we
2903 -- suppress the error report.
2908 -- If type we are looking for is Void, then this is the procedure
2909 -- call case, and the error is simply that what we gave is not a
2910 -- procedure name (we think of procedure calls as expressions with
2911 -- types internally, but the user doesn't think of them this way).
2915 -- Special case message if function used as a procedure
2920 then
2921 Error_Msg_NE
2924 Error_Msg_N
2928 -- Otherwise give general message (not clear what cases this
2929 -- covers, but no harm in providing for them).
2931 else
2937 -- Otherwise we do have a subexpression with the wrong type
2939 -- Check for the case of an allocator which uses an access type
2940 -- instead of the designated type. This is a common error and we
2941 -- specialize the message, posting an error on the operand of the
2942 -- allocator, complaining that we expected the designated type of
2943 -- the allocator.
2949 then
2953 -- Check for view mismatch on Null in instances, for which the
2954 -- view-swapping mechanism has no identifier.
2960 then
2965 -- Check for an aggregate. Sometimes we can get bogus aggregates
2966 -- from misuse of parentheses, and we are about to complain about
2967 -- the aggregate without even looking inside it.
2969 -- Instead, if we have an aggregate of type Any_Composite, then
2970 -- analyze and resolve the component fields, and then only issue
2971 -- another message if we get no errors doing this (otherwise
2972 -- assume that the errors in the aggregate caused the problem).
2976 then
2979 then
2988 -- Disable expansion in any case. If there is a type mismatch
2989 -- it may be fatal to try to expand the aggregate. The flag
2990 -- would otherwise be set to false when the error is posted.
2994 declare
2996 -- Check one aggregate, and set Found to True if we have a
2997 -- definite error in any of its elements
3000 -- Check one element of aggregate and set Found to True if
3001 -- we definitely have an error in the element.
3003 ----------------
3004 -- Check_Aggr --
3005 ----------------
3010 begin
3023 -- If this is a default-initialized component, then
3024 -- there is nothing to check. The box will be
3025 -- replaced by the appropriate call during late
3026 -- expansion.
3030 then
3039 ----------------
3040 -- Check_Elmt --
3041 ----------------
3044 begin
3045 -- If we have a nested aggregate, go inside it (to
3046 -- attempt a naked analyze-resolve of the aggregate can
3047 -- cause undesirable cascaded errors). Do not resolve
3048 -- expression if it needs a type from context, as for
3049 -- integer * fixed expression.
3054 else
3059 then
3069 begin
3074 -- Check whether the node is a literal or a named number or a
3075 -- conditional expression whose dependent expressions are all
3076 -- literals or named numbers.
3082 -- Looks like we have a type error, but check for special case
3083 -- of Address wanted, integer found, with the configuration pragma
3084 -- Allow_Integer_Address active. If we have this case, introduce
3085 -- an unchecked conversion to allow the integer expression to be
3086 -- treated as an Address. The reverse case of integer wanted,
3087 -- Address found, is treated in an analogous manner.
3094 -- Under relaxed RM semantics silently replace occurrences of null
3095 -- by System.Null_Address.
3103 -- That special Allow_Integer_Address check did not apply, so we
3104 -- have a real type error. If an error message was issued already,
3105 -- Found got reset to True, so if it's still False, issue standard
3106 -- Wrong_Type message.
3110 declare
3113 begin
3119 -- Protected operation: retrieve operation name
3123 else
3128 Error_Msg_NE
3134 declare
3138 begin
3145 Error_Msg_NE
3151 else
3155 -- Recognize the case of a quantified expression being mistaken
3156 -- for an iterated component association because the user
3157 -- forgot the "all" or "some" keyword after "for". Because the
3158 -- error message starts with "missing ALL", we automatically
3159 -- benefit from the associated CODEFIX, which requires that
3160 -- the message is located on the identifier following "for"
3161 -- in order for the CODEFIX to insert "all" in the right place.
3166 = N_Iterated_Component_Association
3168 then
3169 if Present
3170 (Iterator_Specification
3172 then
3173 Error_Msg_N -- CODEFIX
3175 Defining_Identifier
3176 (Iterator_Specification
3178 else
3179 Error_Msg_N -- CODEFIX
3181 Defining_Identifier
3185 -- For an operator with no interpretation, check whether one of
3186 -- its operands may be a user-defined literal.
3191 else
3195 else
3201 Resolution_Failed;
3204 -- Test if we have more than one interpretation for the context
3207 Resolution_Failed;
3210 -- Only one interpretation
3212 else
3213 -- Prevent implicit conversions between access-to-subprogram types
3214 -- with different strub modes. Explicit conversions are acceptable in
3215 -- some circumstances. We don't have to be concerned about data or
3216 -- access-to-data types. Conversions between data types can safely
3217 -- drop or add strub attributes from types, because strub effects are
3218 -- associated with the locations rather than values. E.g., converting
3219 -- a hypothetical Strub_Integer variable to Integer would load the
3220 -- value from the variable, enabling stack scrabbing for the
3221 -- enclosing subprogram, and then convert the value to Integer. As
3222 -- for conversions between access-to-data types, that's no different
3223 -- from any other case of type punning.
3229 then
3230 Check_Same_Strub_Mode
3234 -- In Ada 2005, if we have something like "X : T := 2 + 2;", where
3235 -- the "+" on T is abstract, and the operands are of universal type,
3236 -- the above code will have (incorrectly) resolved the "+" to the
3237 -- universal one in Standard. Therefore check for this case and give
3238 -- an error. We can't do this earlier, because it would cause legal
3239 -- cases to get errors (when some other type has an abstract "+").
3245 then
3250 then
3251 Nondispatching_Call_To_Abstract_Operation
3260 -- Here we have an acceptable interpretation for the context
3262 -- Propagate type information and normalize tree for various
3263 -- predefined operations. If the context only imposes a class of
3264 -- types, rather than a specific type, propagate the actual type
3265 -- downward.
3271 Typ = Any_Discrete
3272 then
3275 -- Any_Fixed is legal in a real context only if a specific fixed-
3276 -- point type is imposed. If Norman Cohen can be confused by this,
3277 -- it deserves a separate message.
3281 then
3288 -- A user-defined operator is transformed into a function call at
3289 -- this point, so that further processing knows that operators are
3290 -- really operators (i.e. are predefined operators). User-defined
3291 -- operators that are intrinsic are just renamings of the predefined
3292 -- ones, and need not be turned into calls either, but if they rename
3293 -- a different operator, we must transform the node accordingly.
3294 -- Instantiations of Unchecked_Conversion are intrinsic but are
3295 -- treated as functions, even if given an operator designator.
3300 then
3305 and then
3307 N_Subprogram_Renaming_Declaration
3308 then
3311 -- If the node is rewritten, it will be fully resolved in
3312 -- Rewrite_Renamed_Operator.
3321 when N_Aggregate =>
3322 Resolve_Aggregate (N, Ctx_Type);
3324 when N_Allocator =>
3325 Resolve_Allocator (N, Ctx_Type);
3327 when N_Short_Circuit =>
3328 Resolve_Short_Circuit (N, Ctx_Type);
3330 when N_Attribute_Reference =>
3331 Resolve_Attribute (N, Ctx_Type);
3333 when N_Case_Expression =>
3334 Resolve_Case_Expression (N, Ctx_Type);
3336 when N_Character_Literal =>
3337 Resolve_Character_Literal (N, Ctx_Type);
3339 when N_Delta_Aggregate =>
3340 Resolve_Delta_Aggregate (N, Ctx_Type);
3342 when N_Expanded_Name =>
3343 Resolve_Entity_Name (N, Ctx_Type);
3345 when N_Explicit_Dereference =>
3346 Resolve_Explicit_Dereference (N, Ctx_Type);
3348 when N_Expression_With_Actions =>
3349 Resolve_Expression_With_Actions (N, Ctx_Type);
3351 when N_Extension_Aggregate =>
3352 Resolve_Extension_Aggregate (N, Ctx_Type);
3354 when N_Function_Call =>
3355 Resolve_Call (N, Ctx_Type);
3357 when N_Identifier =>
3358 Resolve_Entity_Name (N, Ctx_Type);
3360 when N_If_Expression =>
3361 Resolve_If_Expression (N, Ctx_Type);
3363 when N_Indexed_Component =>
3364 Resolve_Indexed_Component (N, Ctx_Type);
3366 when N_Integer_Literal =>
3367 Resolve_Integer_Literal (N, Ctx_Type);
3369 when N_Membership_Test =>
3370 Resolve_Membership_Op (N, Ctx_Type);
3372 when N_Null =>
3373 Resolve_Null (N, Ctx_Type);
3375 when N_Op_And
3376 | N_Op_Or
3377 | N_Op_Xor
3378 =>
3379 Resolve_Logical_Op (N, Ctx_Type);
3381 when N_Op_Eq
3382 | N_Op_Ne
3383 =>
3384 Resolve_Equality_Op (N, Ctx_Type);
3386 when N_Op_Ge
3387 | N_Op_Gt
3388 | N_Op_Le
3389 | N_Op_Lt
3390 =>
3391 Resolve_Comparison_Op (N, Ctx_Type);
3393 when N_Op_Not =>
3394 Resolve_Op_Not (N, Ctx_Type);
3396 when N_Op_Add
3397 | N_Op_Divide
3398 | N_Op_Mod
3399 | N_Op_Multiply
3400 | N_Op_Rem
3401 | N_Op_Subtract
3402 =>
3403 Resolve_Arithmetic_Op (N, Ctx_Type);
3405 when N_Op_Concat =>
3406 Resolve_Op_Concat (N, Ctx_Type);
3408 when N_Op_Expon =>
3409 Resolve_Op_Expon (N, Ctx_Type);
3411 when N_Op_Abs
3412 | N_Op_Minus
3413 | N_Op_Plus
3414 =>
3415 Resolve_Unary_Op (N, Ctx_Type);
3417 when N_Op_Shift =>
3418 Resolve_Shift (N, Ctx_Type);
3420 when N_Procedure_Call_Statement =>
3421 Resolve_Call (N, Ctx_Type);
3423 when N_Operator_Symbol =>
3424 Resolve_Operator_Symbol (N, Ctx_Type);
3426 when N_Qualified_Expression =>
3427 Resolve_Qualified_Expression (N, Ctx_Type);
3429 -- Why is the following null, needs a comment ???
3431 when N_Quantified_Expression =>
3432 null;
3434 when N_Raise_Expression =>
3435 Resolve_Raise_Expression (N, Ctx_Type);
3437 when N_Raise_xxx_Error =>
3438 Set_Etype (N, Ctx_Type);
3440 when N_Range =>
3441 Resolve_Range (N, Ctx_Type);
3443 when N_Real_Literal =>
3444 Resolve_Real_Literal (N, Ctx_Type);
3446 when N_Reference =>
3447 Resolve_Reference (N, Ctx_Type);
3449 when N_Selected_Component =>
3450 Resolve_Selected_Component (N, Ctx_Type);
3452 when N_Slice =>
3453 Resolve_Slice (N, Ctx_Type);
3455 when N_String_Literal =>
3456 Resolve_String_Literal (N, Ctx_Type);
3458 when N_Interpolated_String_Literal =>
3459 Resolve_Interpolated_String_Literal (N, Ctx_Type);
3461 when N_Target_Name =>
3462 Resolve_Target_Name (N, Ctx_Type);
3464 when N_Type_Conversion =>
3465 Resolve_Type_Conversion (N, Ctx_Type);
3467 when N_Unchecked_Expression =>
3468 Resolve_Unchecked_Expression (N, Ctx_Type);
3470 when N_Unchecked_Type_Conversion =>
3471 Resolve_Unchecked_Type_Conversion (N, Ctx_Type);
3472 end case;
3474 -- Mark relevant use-type and use-package clauses as effective using
3475 -- the original node because constant folding may have occurred and
3476 -- removed references that need to be examined.
3478 if Nkind (Original_Node (N)) in N_Op then
3479 Mark_Use_Clauses (Original_Node (N));
3480 end if;
3482 -- Ada 2012 (AI05-0149): Apply an (implicit) conversion to an
3483 -- expression of an anonymous access type that occurs in the context
3484 -- of a named general access type, except when the expression is that
3485 -- of a membership test. This ensures proper legality checking in
3486 -- terms of allowed conversions (expressions that would be illegal to
3487 -- convert implicitly are allowed in membership tests).
3489 if Ada_Version >= Ada_2012
3490 and then Ekind (Base_Type (Ctx_Type)) = E_General_Access_Type
3491 and then Ekind (Etype (N)) = E_Anonymous_Access_Type
3492 and then Nkind (Parent (N)) not in N_Membership_Test
3493 then
3494 Rewrite (N, Convert_To (Ctx_Type, Relocate_Node (N)));
3495 Analyze_And_Resolve (N, Ctx_Type);
3496 end if;
3498 -- If the subexpression was replaced by a non-subexpression, then
3499 -- all we do is to expand it. The only legitimate case we know of
3500 -- is converting procedure call statement to entry call statements,
3501 -- but there may be others, so we are making this test general.
3503 if Nkind (N) not in N_Subexpr then
3504 Debug_A_Exit ("resolving ", N, " (done)");
3505 Expand (N);
3506 return;
3507 end if;
3509 -- The expression is definitely NOT overloaded at this point, so
3510 -- we reset the Is_Overloaded flag to avoid any confusion when
3511 -- reanalyzing the node.
3513 Set_Is_Overloaded (N, False);
3515 -- Freeze expression type, entity if it is a name, and designated
3516 -- type if it is an allocator (RM 13.14(10,11,13)).
3518 -- Now that the resolution of the type of the node is complete, and
3519 -- we did not detect an error, we can expand this node. We skip the
3520 -- expand call if we are in a default expression, see section
3521 -- "Handling of Default Expressions" in Sem spec.
3523 Debug_A_Exit ("resolving ", N, " (done)");
3525 -- We unconditionally freeze the expression, even if we are in
3526 -- default expression mode (the Freeze_Expression routine tests this
3527 -- flag and only freezes static types if it is set).
3529 -- Ada 2012 (AI05-177): The declaration of an expression function
3530 -- does not cause freezing, but we never reach here in that case.
3531 -- Here we are resolving the corresponding expanded body, so we do
3532 -- need to perform normal freezing.
3534 -- As elsewhere we do not emit freeze node within a generic.
3536 if not Inside_A_Generic then
3537 Freeze_Expression (N);
3538 end if;
3540 -- Now we can do the expansion
3542 Expand (N);
3543 end if;
3544 end Resolve;
3546 -------------
3547 -- Resolve --
3548 -------------
3550 -- Version with check(s) suppressed
3552 procedure Resolve (N : Node_Id; Typ : Entity_Id; Suppress : Check_Id) is
3553 begin
3554 if Suppress = All_Checks then
3555 declare
3556 Sva : constant Suppress_Array := Scope_Suppress.Suppress;
3557 begin
3558 Scope_Suppress.Suppress := (others => True);
3559 Resolve (N, Typ);
3560 Scope_Suppress.Suppress := Sva;
3561 end;
3563 else
3564 declare
3565 Svg : constant Boolean := Scope_Suppress.Suppress (Suppress);
3566 begin
3567 Scope_Suppress.Suppress (Suppress) := True;
3568 Resolve (N, Typ);
3569 Scope_Suppress.Suppress (Suppress) := Svg;
3570 end;
3571 end if;
3572 end Resolve;
3574 -------------
3575 -- Resolve --
3576 -------------
3578 -- Version with implicit type
3580 procedure Resolve (N : Node_Id) is
3581 begin
3582 Resolve (N, Etype (N));
3583 end Resolve;
3585 ---------------------
3586 -- Resolve_Actuals --
3587 ---------------------
3589 procedure Resolve_Actuals (N : Node_Id; Nam : Entity_Id) is
3590 Loc : constant Source_Ptr := Sloc (N);
3591 A : Node_Id;
3592 A_Typ : Entity_Id := Empty; -- init to avoid warning
3593 F : Entity_Id;
3594 F_Typ : Entity_Id;
3595 Prev : Node_Id := Empty;
3596 Orig_A : Node_Id;
3597 Real_F : Entity_Id := Empty; -- init to avoid warning
3599 Real_Subp : Entity_Id;
3600 -- If the subprogram being called is an inherited operation for
3601 -- a formal derived type in an instance, Real_Subp is the subprogram
3602 -- that will be called. It may have different formal names than the
3603 -- operation of the formal in the generic, so after actual is resolved
3604 -- the name of the actual in a named association must carry the name
3605 -- of the actual of the subprogram being called.
3607 procedure Check_Aliased_Parameter;
3608 -- Check rules on aliased parameters and related accessibility rules
3609 -- in (RM 3.10.2 (10.2-10.4)).
3611 procedure Check_Argument_Order;
3612 -- Performs a check for the case where the actuals are all simple
3613 -- identifiers that correspond to the formal names, but in the wrong
3614 -- order, which is considered suspicious and cause for a warning.
3616 procedure Check_Prefixed_Call;
3617 -- If the original node is an overloaded call in prefix notation,
3619 -- Try_Object_Operation has already verified that there is a valid
3620 -- interpretation, but the form of the actual can only be determined
3621 -- once the primitive operation is identified.
3624 -- If the actual is missing in a call, insert in the actuals list
3625 -- an instance of the default expression. The insertion is always
3626 -- a named association.
3629 -- Check whether T1 and T2, or their full views, are derived from a
3630 -- common type. Used to enforce the restrictions on array conversions
3631 -- of AI95-00246.
3634 -- Predicate to determine whether an actual that is a concatenation
3635 -- will be evaluated statically and does not need a transient scope.
3636 -- This must be determined before the actual is resolved and expanded
3637 -- because if needed the transient scope must be introduced earlier.
3639 -----------------------------
3640 -- Check_Aliased_Parameter --
3641 -----------------------------
3646 begin
3654 else
3661 -- In a generic body assume the worst for generic formals:
3662 -- they can have a constrained partial view (AI05-041).
3666 and then not Object_Type_Has_Constrained_Partial_View
3668 then
3671 else
3676 else
3688 then
3696 then
3697 Error_Msg_N
3703 --------------------------
3704 -- Check_Argument_Order --
3705 --------------------------
3708 begin
3709 -- Nothing to do if no parameters, or original node is neither a
3710 -- function call nor a procedure call statement (happens in the
3711 -- operator-transformed-to-function call case), or the call is to an
3712 -- operator symbol (which is usually in infix form), or the call does
3713 -- not come from source, or this warning is off.
3715 if not Warn_On_Parameter_Order
3721 N_Defining_Operator_Symbol)
3723 then
3727 declare
3730 begin
3731 -- Nothing to do if only one parameter
3737 -- Here if at least two arguments
3739 declare
3745 -- Set True if an out of order case is found
3747 begin
3748 -- Collect identifier names of actuals, fail if any actual is
3749 -- not a simple identifier, and record max length of name.
3755 else
3761 -- If we got this far, all actuals are identifiers and the list
3762 -- of their names is stored in the Actuals array.
3767 -- If we ran out of formals, that's odd, probably an error
3768 -- which will be detected elsewhere, but abandon the search.
3774 -- If name matches and is in order OK
3779 else
3780 -- If no match, see if it is elsewhere in list and if so
3781 -- flag potential wrong order if type is compatible.
3785 and then
3787 then
3793 -- No match
3801 -- If Formals left over, also probably an error, skip warning
3807 -- Here we give the warning if something was out of order
3810 Error_Msg_N
3817 -------------------------
3818 -- Check_Prefixed_Call --
3819 -------------------------
3828 begin
3829 -- Check whether the call is a prefixed call, with or without
3830 -- additional actuals.
3833 or else
3839 then
3842 then
3843 -- Introduce dereference on object in prefix
3845 New_A :=
3853 then
3854 -- Introduce an implicit 'Access in prefix
3857 Error_Msg_NE
3873 --------------------
3874 -- Insert_Default --
3875 --------------------
3881 begin
3882 -- Missing argument in call, nothing to insert
3887 else
3888 -- Note that we do a full New_Copy_Tree, so that any associated
3889 -- Itypes are properly copied. This may not be needed any more,
3890 -- but it does no harm as a safety measure. Defaults of a generic
3891 -- formal may be out of bounds of the corresponding actual (see
3892 -- cc1311b) and an additional check may be required.
3894 Actval :=
3895 New_Copy_Tree
3900 -- Propagate dimension information, if any.
3906 then
3912 then
3915 then
3916 -- If default is a real literal, do not introduce a
3917 -- conversion whose effect may depend on the run-time
3918 -- size of universal real.
3922 else
3933 -- Resolve aggregates with their base type, to avoid scope
3934 -- anomalies: the subtype was first built in the subprogram
3935 -- declaration, and the current call may be nested.
3939 else
3943 else
3946 -- See note above concerning aggregates
3950 then
3953 -- Resolve entities with their own type, which may differ from
3954 -- the type of a reference in a generic context because of the
3955 -- trick used in Save_Global_References.Set_Global_Type to set
3956 -- full views forcefully, which did not anticipate the need to
3957 -- re-analyze default values in calls.
3962 -- Ditto for calls whose name is an entity, for the same reason
3966 then
3969 else
3974 -- If default is a tag indeterminate function call, propagate tag
3975 -- to obtain proper dispatching.
3979 then
3984 -- If the default expression raises constraint error, then just
3985 -- silently replace it with an N_Raise_Constraint_Error node, since
3986 -- we already gave the warning on the subprogram spec. If node is
3987 -- already a Raise_Constraint_Error leave as is, to prevent loops in
3988 -- the warnings removal machinery.
3992 then
4001 Assoc :=
4006 -- Case of insertion is first named actual
4010 then
4017 else
4021 else
4025 -- Case of insertion is not first named actual
4027 else
4028 Set_Next_Named_Actual
4040 -------------------
4041 -- Same_Ancestor --
4042 -------------------
4048 begin
4051 then
4057 then
4064 --------------------------
4065 -- Static_Concatenation --
4066 --------------------------
4069 begin
4076 -- Concatenation is static when both operands are static and
4077 -- the concatenation operator is a predefined one.
4080 and then
4082 and then
4087 declare
4089 begin
4092 and then
4096 else
4102 -- Start of processing for Resolve_Actuals
4104 begin
4105 Check_Argument_Order;
4109 and then In_Instance
4112 then
4114 else
4119 Check_Prefixed_Call;
4133 -- If we have an error in any formal or actual, indicated by a type
4134 -- of Any_Type, then abandon resolution attempt, and set result type
4135 -- to Any_Type.
4142 -- For the peculiar case of a user-defined comparison or equality
4143 -- operator that does not return a boolean type, the operands may
4144 -- have been ambiguous for the predefined operator and, therefore,
4145 -- marked with Any_Type. Since the operation has been resolved to
4146 -- the user-defined operator, that is irrelevant, so reset Etype.
4150 then
4153 -- Also skip this if the actual is a Raise_Expression, whose type
4154 -- is imposed from context.
4159 else
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 -- For mode IN, if actual is an entity, and the type of the formal
4591 -- has warnings suppressed, then we reset Never_Set_In_Source for
4592 -- the calling entity. The reason for this is to catch cases like
4593 -- GNAT.Spitbol.Patterns.Vstring_Var where the called subprogram
4594 -- uses trickery to modify an IN parameter.
4601 then
4605 -- Perform error checks for IN and IN OUT parameters
4609 -- Check unset reference. For scalar parameters, it is clearly
4610 -- wrong to pass an uninitialized value as either an IN or
4611 -- IN-OUT parameter. For composites, it is also clearly an
4612 -- error to pass a completely uninitialized value as an IN
4613 -- parameter, but the case of IN OUT is trickier. We prefer
4614 -- not to give a warning here. For example, suppose there is
4615 -- a routine that sets some component of a record to False.
4616 -- It is perfectly reasonable to make this IN-OUT and allow
4617 -- either initialized or uninitialized records to be passed
4618 -- in this case.
4620 -- For partially initialized composite values, we also avoid
4621 -- warnings, since it is quite likely that we are passing a
4622 -- partially initialized value and only the initialized fields
4623 -- will in fact be read in the subprogram.
4628 then
4632 -- In Ada 83 we cannot pass an OUT parameter as an IN or IN OUT
4633 -- actual to a nested call, since this constitutes a reading of
4634 -- the parameter, which is not allowed.
4639 then
4644 -- In -gnatd.q mode, forget that a given array is constant when
4645 -- it is passed as an IN parameter to a foreign-convention
4646 -- subprogram. This is in case the subprogram evilly modifies the
4647 -- object. Of course, correct code would use IN OUT.
4649 if Debug_Flag_Dot_Q
4655 then
4659 -- Case of OUT or IN OUT parameter
4663 -- For an Out parameter, check for useless assignment. Note
4664 -- that we can't set Last_Assignment this early, because we may
4665 -- kill current values in Resolve_Call, and that call would
4666 -- clobber the Last_Assignment field.
4668 -- Note: call Warn_On_Useless_Assignment before doing the check
4669 -- below for Is_OK_Variable_For_Out_Formal so that the setting
4670 -- of Referenced_As_LHS/Referenced_As_Out_Formal properly
4671 -- reflects the last assignment, not this one.
4678 then
4683 -- Validate the form of the actual. Note that the call to
4684 -- Is_OK_Variable_For_Out_Formal generates the required
4685 -- reference in this case.
4687 -- A call to an initialization procedure for an aggregate
4688 -- component may initialize a nested component of a constant
4689 -- designated object. In this context the object is variable.
4693 then
4699 then
4700 Error_Msg_N
4705 Error_Msg_N
4712 -- What's the following about???
4716 else
4717 Kill_All_Checks;
4726 -- Apply appropriate constraint/predicate checks for IN [OUT] case
4730 -- Apply predicate tests except in certain special cases. Note
4731 -- that it might be more consistent to apply these only when
4732 -- expansion is active (in Exp_Ch6.Expand_Actuals), as we do
4733 -- for the outbound predicate tests ??? In any case indicate
4734 -- the function being called, for better warnings if the call
4735 -- leads to an infinite recursion.
4741 -- Apply required constraint checks
4754 then
4757 -- For view conversions of a discriminated object, apply
4758 -- check to object itself, the conversion alreay has the
4759 -- proper type.
4763 then
4770 then
4776 then
4779 else
4783 -- Ada 2005 (AI-231): Note that the controlling parameter case
4784 -- already existed in Ada 95, which is partially checked
4785 -- elsewhere (see Checks), and we don't want the warning
4786 -- message to differ.
4791 then
4793 Apply_Compile_Time_Constraint_Error
4799 Apply_Compile_Time_Constraint_Error
4808 -- Checks for OUT parameters and IN OUT parameters
4812 -- If there is a type conversion, make sure the return value
4813 -- meets the constraints of the variable before the conversion.
4818 -- Special case here tailored to Exp_Ch6.Is_Legal_Copy,
4819 -- which would prevent the check from being generated.
4820 -- This is for Starlet only though, so long obsolete.
4825 then
4827 else
4828 Apply_Scalar_Range_Check
4832 -- In addition the return value must meet the constraints
4833 -- of the object type (see the comment below).
4837 else
4838 Apply_Range_Check
4842 -- If no conversion, apply scalar range checks and length check
4843 -- based on the subtype of the actual (NOT that of the formal).
4844 -- This indicates that the check takes place on return from the
4845 -- call. During expansion the required constraint checks are
4846 -- inserted. In GNATprove mode, in the absence of expansion,
4847 -- the flag indicates that the returned value is valid.
4849 else
4855 then
4858 else
4863 -- Note: we do not apply the predicate checks for the case of
4864 -- OUT and IN OUT parameters. They are instead applied in the
4865 -- Expand_Actuals routine in Exp_Ch6.
4868 -- If the formal is of an unconstrained array subtype with fixed
4869 -- lower bound, then sliding to that bound may be needed.
4875 -- An actual associated with an access parameter is implicitly
4876 -- converted to the anonymous access type of the formal and must
4877 -- satisfy the legality checks for access conversions.
4881 Error_Msg_N
4885 -- If the actual is an access selected component of a variable,
4886 -- the call may modify its designated object. It is reasonable
4887 -- to treat this as a potential modification of the enclosing
4888 -- record, to prevent spurious warnings that it should be
4889 -- declared as a constant, because intuitively programmers
4890 -- regard the designated subcomponent as part of the record.
4895 then
4900 -- Check illegal cases of atomic/volatile/VFA actual (RM C.6(12))
4904 then
4907 then
4908 Error_Msg_NE
4911 Error_Msg_N
4916 then
4917 Error_Msg_NE
4920 Error_Msg_N
4925 then
4926 Error_Msg_NE
4929 Error_Msg_N
4933 -- Check for nonatomic subcomponent of a full access object
4934 -- in Ada 2022 (RM C.6 (12)).
4939 then
4940 Error_Msg_N
4943 Error_Msg_NE
4949 -- Check that subprograms don't have improper controlling
4950 -- arguments (RM 3.9.2 (9)).
4952 -- A primitive operation may have an access parameter of an
4953 -- incomplete tagged type, but a dispatching call is illegal
4954 -- if the type is still incomplete.
4960 declare
4962 begin
4966 then
4967 Error_Msg_NE
4978 -- Apply legality rule 3.9.2 (9/1)
4980 -- Skip this check on helpers and indirect-call wrappers built to
4981 -- support class-wide preconditions.
4986 and then not In_Instance
4989 then
4994 Error_Msg_NE
4998 -- Apply the checks described in 3.10.2(27): if the context is a
4999 -- specific access-to-object, the actual cannot be class-wide.
5000 -- Use base type to exclude access_to_subprogram cases.
5007 and then
5012 -- Disable these checks for call to imported C++ subprograms
5014 and then not
5018 then
5019 Error_Msg_N
5024 Error_Msg_NE
5029 Check_Aliased_Parameter;
5033 -- If it is a named association, treat the selector_name as a
5034 -- proper identifier, and mark the corresponding entity.
5038 -- Ignore reference in SPARK mode, as it refers to an entity not
5039 -- in scope at the point of reference, so the reference should
5040 -- be ignored for computing effects of subprograms.
5042 and then not GNATprove_Mode
5043 then
5044 -- If subprogram is overridden, use name of formal that
5045 -- is being called.
5051 else
5065 -- A formal parameter of a specific tagged type whose related
5066 -- subprogram is subject to pragma Extensions_Visible with value
5067 -- "False" cannot act as an actual in a subprogram with value
5068 -- "True" (SPARK RM 6.1.7(3)).
5070 -- No check needed for helpers and indirect-call wrappers built to
5071 -- support class-wide preconditions.
5075 Extensions_Visible_True
5076 and then not
5078 and then
5080 then
5081 Error_Msg_N
5084 Error_Msg_NE
5088 -- The actual parameter of a Ghost subprogram whose formal is of
5089 -- mode IN OUT or OUT must be a Ghost variable (SPARK RM 6.9(12)).
5097 then
5098 Error_Msg_NE
5104 else
5109 -- (AI12-0397): The target of a subprogram call that occurs within
5110 -- the expression of an Default_Initial_Condition aspect and has
5111 -- an actual that is the current instance of the type must be
5112 -- either a primitive of the type or a class-wide subprogram,
5113 -- because the type of the current instance in such an aspect is
5114 -- considered to be a notional formal derived type whose only
5115 -- operations correspond to the primitives of the enclosing type.
5116 -- Nonprimitives can be called, but the current instance must be
5117 -- converted rather than passed directly. Note that a current
5118 -- instance of a type with DIC will occur as a reference to an
5119 -- in-mode formal of an enclosing DIC procedure or partial DIC
5120 -- procedure. (It seems that this check should perhaps also apply
5121 -- to calls within Type_Invariant'Class, but not Type_Invariant,
5122 -- aspects???)
5130 -- We check Comes_From_Source to exclude inherited primitives
5131 -- from being flagged, because such subprograms turn out to not
5132 -- always have the Is_Primitive flag set. ???
5138 then
5139 Error_Msg_NE
5146 -- Case where actual is not present
5148 else
5149 Insert_Default;
5160 -----------------------
5161 -- Resolve_Allocator --
5162 -----------------------
5174 procedure Check_Allocator_Discrim_Accessibility
5177 -- Check that accessibility level associated with an access discriminant
5178 -- initialized in an allocator by the expression Disc_Exp is not deeper
5179 -- than the level of the allocator type Alloc_Typ. An error message is
5180 -- issued if this condition is violated. Specialized checks are done for
5181 -- the cases of a constraint expression which is an access attribute or
5182 -- an access discriminant.
5184 procedure Check_Allocator_Discrim_Accessibility_Exprs
5187 -- Dispatch checks performed by Check_Allocator_Discrim_Accessibility
5188 -- across all expressions within a given conditional expression.
5191 -- If the allocator is an actual in a call, it is allowed to be class-
5192 -- wide when the context is not because it is a controlling actual.
5194 -------------------------------------------
5195 -- Check_Allocator_Discrim_Accessibility --
5196 -------------------------------------------
5198 procedure Check_Allocator_Discrim_Accessibility
5201 is
5202 begin
5205 then
5206 Error_Msg_N
5209 -- When the expression is an Access attribute the level of the prefix
5210 -- object must not be deeper than that of the allocator's type.
5214 Attribute_Access
5215 and then Static_Accessibility_Level
5218 then
5219 Error_Msg_N
5221 Disc_Exp);
5223 -- When the expression is an access discriminant the check is against
5224 -- the level of the prefix object.
5228 and then Static_Accessibility_Level
5231 then
5232 Error_Msg_N
5234 Disc_Exp);
5236 -- All other cases are legal
5238 else
5243 -------------------------------------------------
5244 -- Check_Allocator_Discrim_Accessibility_Exprs --
5245 -------------------------------------------------
5247 procedure Check_Allocator_Discrim_Accessibility_Exprs
5250 is
5254 begin
5255 -- When conditional expressions are constant folded we know at
5256 -- compile time which expression to check - so don't bother with
5257 -- the rest of the cases.
5262 -- Non-constant-folded if expressions
5265 -- Check both expressions if they are still present in the face
5266 -- of expansion.
5273 Check_Allocator_Discrim_Accessibility_Exprs
5278 -- Non-constant-folded case expressions
5281 -- Check all alternatives
5285 Check_Allocator_Discrim_Accessibility_Exprs
5291 -- Base case, check the accessibility of the original node of the
5292 -- expression.
5294 else
5299 ----------------------------
5300 -- In_Dispatching_Context --
5301 ----------------------------
5306 begin
5312 -- Start of processing for Resolve_Allocator
5314 begin
5315 -- Replace general access with specific type
5325 -- For qualified expression, resolve the expression using the given
5326 -- subtype (nothing to do for type mark, subtype indication)
5331 and then not In_Dispatching_Context
5332 then
5333 Error_Msg_N
5337 -- Do a full resolution to apply constraint and predicate checks
5342 -- Allocators generated by the build-in-place expansion mechanism
5343 -- are explicitly marked as coming from source but do not need to be
5344 -- checked for limited initialization. To exclude this case, ensure
5345 -- that the parent of the allocator is a source node.
5346 -- The return statement constructed for an Expression_Function does
5347 -- not come from source but requires a limited check.
5351 and then
5353 or else
5357 and then not In_Instance_Body
5358 then
5361 Error_Msg_N
5364 else
5365 Error_Msg_N
5373 -- Calls to build-in-place functions are not currently supported in
5374 -- allocators for access types associated with a simple storage pool.
5375 -- Supporting such allocators may require passing additional implicit
5376 -- parameters to build-in-place functions (or a significant revision
5377 -- of the current b-i-p implementation to unify the handling for
5378 -- multiple kinds of storage pools). ???
5382 then
5383 declare
5386 begin
5388 and then
5389 Present (Get_Rep_Pragma
5391 then
5392 Error_Msg_N
5399 -- A special accessibility check is needed for allocators that
5400 -- constrain access discriminants. The level of the type of the
5401 -- expression used to constrain an access discriminant cannot be
5402 -- deeper than the type of the allocator (in contrast to access
5403 -- parameters, where the level of the actual can be arbitrary).
5405 -- We can't use Valid_Conversion to perform this check because in
5406 -- general the type of the allocator is unrelated to the type of
5407 -- the access discriminant.
5411 then
5418 then
5421 -- Get the first component expression of the aggregate
5431 else
5435 else
5441 Check_Allocator_Discrim_Accessibility_Exprs
5455 else
5460 else
5469 -- For a subtype mark or subtype indication, freeze the subtype
5471 else
5475 Error_Msg_N
5479 -- A special accessibility check is needed for allocators that
5480 -- constrain access discriminants. The level of the type of the
5481 -- expression used to constrain an access discriminant cannot be
5482 -- deeper than the type of the allocator (in contrast to access
5483 -- parameters, where the level of the actual can be arbitrary).
5484 -- We can't use Valid_Conversion to perform this check because
5485 -- in general the type of the allocator is unrelated to the type
5486 -- of the access discriminant.
5491 then
5501 else
5505 Check_Allocator_Discrim_Accessibility_Exprs
5516 -- Ada 2005 (AI-344): A class-wide allocator requires an accessibility
5517 -- check that the level of the type of the created object is not deeper
5518 -- than the level of the allocator's access type, since extensions can
5519 -- now occur at deeper levels than their ancestor types. This is a
5520 -- static accessibility level check; a run-time check is also needed in
5521 -- the case of an initialized allocator with a class-wide argument (see
5522 -- Expand_Allocator_Expression).
5526 then
5527 declare
5530 begin
5535 else
5541 then
5544 Error_Msg_N
5554 -- Do not apply Ada 2005 accessibility checks on a class-wide
5555 -- allocator if the type given in the allocator is a formal
5556 -- type or within a formal package. A run-time check will be
5557 -- performed in the instance.
5561 then
5562 Error_Msg_N
5570 -- Check for allocation from an empty storage pool. But do not complain
5571 -- if it's a return statement for a build-in-place function, because the
5572 -- allocator is there just in case the caller uses an allocator. If the
5573 -- caller does use an allocator, it will be caught at the call site.
5577 then
5580 -- If the context is an unchecked conversion, as may happen within an
5581 -- inlined subprogram, the allocator is being resolved with its own
5582 -- anonymous type. In that case, if the target type has a specific
5583 -- storage pool, it must be inherited explicitly by the allocator type.
5587 then
5588 Set_Associated_Storage_Pool
5596 -- Check that an allocator with task parts isn't for a nested access
5597 -- type when restriction No_Task_Hierarchy applies.
5601 then
5605 -- An illegal allocator may be rewritten as a raise Program_Error
5606 -- statement.
5610 -- Avoid coextension processing for an allocator that is the
5611 -- expansion of a build-in-place function call.
5615 N_Qualified_Expression
5617 N_Function_Call
5618 and then Is_Expanded_Build_In_Place_Call
5620 then
5623 else
5624 -- An anonymous access discriminant is the definition of a
5625 -- coextension.
5629 N_Discriminant_Specification
5630 then
5631 declare
5635 begin
5638 -- Ada 2012 AI05-0052: If the designated type of the
5639 -- allocator is limited, then the allocator shall not
5640 -- be used to define the value of an access discriminant
5641 -- unless the discriminated type is immutably limited.
5646 then
5647 Error_Msg_N
5650 N);
5654 -- Avoid marking an allocator as a dynamic coextension if it is
5655 -- within a static construct.
5660 -- Finalization and deallocation of coextensions utilizes an
5661 -- approximate implementation which does not directly adhere
5662 -- to the semantic rules. Warn on potential issues involving
5663 -- coextensions.
5666 Error_Msg_N
5669 else
5670 Error_Msg_N
5676 -- Cleanup for potential static coextensions
5678 else
5682 -- Objects allocated through anonymous access types are not
5683 -- finalized on time because this involves run-time ownership
5684 -- and currently this property is not available. In rare cases
5685 -- the object might not be finalized at all. Warn on potential
5686 -- issues involving anonymous access-to-controlled types.
5690 then
5691 Error_Msg_N
5701 -- Report a simple error: if the designated object is a local task,
5702 -- its body has not been seen yet, and its activation will fail an
5703 -- elaboration check.
5710 then
5716 -- Ada 2012 (AI05-0111-3): Detect an attempt to allocate a task or a
5717 -- type with a task component on a subpool. This action must raise
5718 -- Program_Error at runtime.
5724 then
5736 ---------------------------
5737 -- Resolve_Arithmetic_Op --
5738 ---------------------------
5740 -- Used for resolving all arithmetic operators except exponentiation
5751 -- We do the resolution using the base type, because intermediate values
5752 -- in expressions always are of the base type, not a subtype of it.
5755 -- Returns True if N is in a context that expects "any real type"
5758 -- Return True iff given type is Integer or universal real/integer
5761 -- Choose type of integer literal in fixed-point operation to conform
5762 -- to available fixed-point type. T is the type of the other operand,
5763 -- which is needed to determine the expected type of N.
5766 -- Set operand type to T if universal
5768 -------------------------------
5769 -- Expected_Type_Is_Any_Real --
5770 -------------------------------
5773 begin
5774 -- N is the expression after "delta" in a fixed_point_definition;
5775 -- see RM-3.5.9(6):
5778 | N_Decimal_Fixed_Point_Definition
5780 -- N is one of the bounds in a real_range_specification;
5781 -- see RM-3.5.7(5):
5783 | N_Real_Range_Specification
5785 -- N is the expression of a delta_constraint;
5786 -- see RM-J.3(3):
5788 | N_Delta_Constraint;
5791 -----------------------------
5792 -- Is_Integer_Or_Universal --
5793 -----------------------------
5800 begin
5805 else
5810 then
5821 ----------------------------
5822 -- Set_Mixed_Mode_Operand --
5823 ----------------------------
5829 begin
5832 -- A universal integer literal is resolved as standard integer
5833 -- except in the case of a fixed-point result, where we leave it
5834 -- as universal (to be handled by Exp_Fixd later on)
5838 else
5845 then
5846 -- A universal real can appear in a fixed-type context. We resolve
5847 -- the literal with that context, even though this might raise an
5848 -- exception prematurely (the other operand may be zero).
5855 then
5856 -- Integer arg in mixed-mode operation. Resolve with universal
5857 -- type, in case preference rule must be applied.
5863 -- If the operand is part of a fixed multiplication operation,
5864 -- a conversion will be applied to each operand, so resolve it
5865 -- with its own type.
5870 else
5871 -- Not a mixed-mode operation, resolve with context
5878 -- N may itself be a mixed-mode operation, so use context type
5885 then
5886 -- Must be (fixed * fixed) operation, operand must have one
5887 -- compatible interpretation.
5894 then
5895 -- C * F(X) in a fixed context, where C is a real literal or a
5896 -- fixed-point expression. F must have either a fixed type
5897 -- interpretation or an integer interpretation, but not both.
5904 else
5911 else
5919 -- Reanalyze the literal with the fixed type of the context. If
5920 -- context is Universal_Fixed, we are within a conversion, leave
5921 -- the literal as a universal real because there is no usable
5922 -- fixed type, and the target of the conversion plays no role in
5923 -- the resolution.
5925 declare
5929 begin
5932 else
5938 then
5940 else
5948 -- A universal real conditional expression can appear in a fixed-type
5949 -- context and must be resolved with that context to facilitate the
5950 -- code generation in the back end. However, If the context is
5951 -- Universal_fixed (i.e. as an operand of a multiplication/division
5952 -- involving a fixed-point operand) the conditional expression must
5953 -- resolve to a unique visible fixed_point type, normally Duration.
5958 then
5962 else
5966 else
5971 ----------------------
5972 -- Set_Operand_Type --
5973 ----------------------
5976 begin
5982 -- Start of processing for Resolve_Arithmetic_Op
5984 begin
5988 then
5993 -- Special-case for mixed-mode universal expressions or fixed point type
5994 -- operation: each argument is resolved separately. The same treatment
5995 -- is required if one of the operands of a fixed point operation is
5996 -- universal real, since in this case we don't do a conversion to a
5997 -- specific fixed-point type (instead the expander handles the case).
5999 -- Set the type of the node to its universal interpretation because
6000 -- legality checks on an exponentiation operand need the context.
6005 then
6016 or else
6019 then
6024 -- If context is a fixed type and one operand is integer, the other
6025 -- is resolved with the type of the context.
6030 then
6037 then
6041 -- If both operands are universal and the context is a floating
6042 -- point type, the operands are resolved to the type of the context.
6048 else
6053 -- Check the rule in RM05-4.5.5(19.1/2) disallowing universal_fixed
6054 -- multiplying operators from being used when the expected type is
6055 -- also universal_fixed. Note that B_Typ will be Universal_Fixed in
6056 -- some cases where the expected type is actually Any_Real;
6057 -- Expected_Type_Is_Any_Real takes care of that case.
6061 then
6065 N_Type_Conversion | N_Unchecked_Type_Conversion
6066 then
6073 else
6077 N_Type_Conversion | N_Unchecked_Type_Conversion
6078 then
6079 Error_Msg_N
6084 -- The expected type is "any real type" in contexts like
6086 -- type T is delta <universal_fixed-expression> ...
6088 -- in which case we need to set the type to Universal_Real
6089 -- so that static expression evaluation will work properly.
6093 else
6103 then
6108 -- If no previous errors, this is only possible if one operand is
6109 -- overloaded and the context is universal. Resolve as such.
6114 else
6116 and then
6118 then
6122 -- If the context is Universal_Fixed and the operands are also
6123 -- universal fixed, this is an error, unless there is only one
6124 -- applicable fixed_point type (usually Duration).
6132 else
6137 else
6142 -- If one of the arguments was resolved to a non-universal type.
6143 -- label the result of the operation itself with the same type.
6144 -- Do the same for the universal argument, if any.
6156 -- Set overflow and division checking bit
6163 -- Give warning if explicit division by zero
6167 then
6173 or else
6176 then
6177 -- Specialize the warning message according to the operation.
6178 -- When SPARK_Mode is On, force a warning instead of an error
6179 -- in that case, as this likely corresponds to deactivated
6180 -- code. The following warnings are for the case
6185 -- For division, we have two cases, for float division
6186 -- of an unconstrained float type, on a machine where
6187 -- Machine_Overflows is false, we don't get an exception
6188 -- at run-time, but rather an infinity or Nan. The Nan
6189 -- case is pretty obscure, so just warn about infinities.
6193 and then not Machine_Overflows_On_Target
6194 then
6195 Error_Msg_N
6199 -- For all other cases, we get a Constraint_Error
6201 else
6202 Apply_Compile_Time_Constraint_Error
6209 Apply_Compile_Time_Constraint_Error
6215 Apply_Compile_Time_Constraint_Error
6220 -- Division by zero can only happen with division, rem,
6221 -- and mod operations.
6227 -- Otherwise just set the flag to check at run time
6229 else
6234 -- If Restriction No_Implicit_Conditionals is active, then it is
6235 -- violated if either operand can be negative for mod, or for rem
6236 -- if both operands can be negative.
6240 then
6241 declare
6248 -- Set if corresponding operand might be negative
6250 begin
6251 Determine_Range
6255 Determine_Range
6259 -- Check if we will be generating conditionals. There are two
6260 -- cases where that can happen, first for REM, the only case
6261 -- is largest negative integer mod -1, where the division can
6262 -- overflow, but we still have to give the right result. The
6263 -- front end generates a test for this annoying case. Here we
6264 -- just test if both operands can be negative (that's what the
6265 -- expander does, so we match its logic here).
6267 -- The second case is mod where either operand can be negative.
6268 -- In this case, the back end has to generate additional tests.
6271 or else
6273 then
6284 ------------------
6285 -- Resolve_Call --
6286 ------------------
6301 begin
6302 -- Preserve relevant elaboration-related attributes of the context which
6303 -- are no longer available or very expensive to recompute once analysis,
6304 -- resolution, and expansion are over.
6306 Mark_Elaboration_Attributes
6312 -- The context imposes a unique interpretation with type Typ on a
6313 -- procedure or function call. Find the entity of the subprogram that
6314 -- yields the expected type, and propagate the corresponding formal
6315 -- constraints on the actuals. The caller has established that an
6316 -- interpretation exists, and emitted an error if not unique.
6318 -- First deal with the case of a call to an access-to-subprogram,
6319 -- dereference made explicit in Analyze_Call.
6325 else
6326 -- Find the interpretation whose type (a subprogram type) has a
6327 -- return type that is compatible with the context. Analysis of
6328 -- the node has established that one exists.
6347 -- If the prefix is not an entity, then resolve it
6353 -- For an indirect call, we always invalidate checks, since we do not
6354 -- know whether the subprogram is local or global. Yes we could do
6355 -- better here, e.g. by knowing that there are no local subprograms,
6356 -- but it does not seem worth the effort. Similarly, we kill all
6357 -- knowledge of current constant values.
6359 Kill_Current_Values;
6361 -- If this is a procedure call which is really an entry call, do
6362 -- the conversion of the procedure call to an entry call. Protected
6363 -- operations use the same circuitry because the name in the call
6364 -- can be an arbitrary expression with special resolution rules.
6368 then
6375 -- Annotate the tree by creating a call marker in case the original
6376 -- call is transformed by expansion. The call marker is automatically
6377 -- saved for later examination by the ABE Processing phase.
6381 -- Kill checks and constant values, as above for indirect case
6382 -- Who knows what happens when another task is activated?
6384 Kill_Current_Values;
6387 -- Normal subprogram call with name established in Resolve
6393 -- Otherwise we must have the case of an overloaded call
6395 else
6398 -- Initialize Nam to prevent warning (we know it will be assigned
6399 -- in the loop below, but the compiler does not know that).
6415 -- Check that a call to Current_Task does not occur in an entry body
6418 declare
6421 begin
6423 loop
6426 -- Exclude calls that occur within the default of a formal
6427 -- parameter of the entry, since those are evaluated outside
6428 -- of the body.
6435 then
6438 Error_Msg_NE
6452 -- Check that a procedure call does not occur in the context of the
6453 -- entry call statement of a conditional or timed entry call. Note that
6454 -- the case of a call to a subprogram renaming of an entry will also be
6455 -- rejected. The test for N not being an N_Entry_Call_Statement is
6456 -- defensive, covering the possibility that the processing of entry
6457 -- calls might reach this point due to later modifications of the code
6458 -- above.
6463 then
6467 -- Ada 2005 (AI-345): If a procedure_call_statement is used
6468 -- for a procedure_or_entry_call, the procedure_name or
6469 -- procedure_prefix of the procedure_call_statement shall denote
6470 -- an entry renamed by a procedure, or (a view of) a primitive
6471 -- subprogram of a limited interface whose first parameter is
6472 -- a controlling parameter.
6477 then
6478 Error_Msg_N
6483 -- Check that this is not a call to a protected procedure or entry from
6484 -- within a protected function.
6488 -- Freeze the subprogram name if not in a spec-expression. Note that
6489 -- we freeze procedure calls as well as function calls. Procedure calls
6490 -- are not frozen according to the rules (RM 13.14(14)) because it is
6491 -- impossible to have a procedure call to a non-frozen procedure in
6492 -- pure Ada, but in the code that we generate in the expander, this
6493 -- rule needs extending because we can generate procedure calls that
6494 -- need freezing.
6496 -- In Ada 2012, expression functions may be called within pre/post
6497 -- conditions of subsequent functions or expression functions. Such
6498 -- calls do not freeze when they appear within generated bodies,
6499 -- (including the body of another expression function) which would
6500 -- place the freeze node in the wrong scope. An expression function
6501 -- is frozen in the usual fashion, by the appearance of a real body,
6502 -- or at the end of a declarative part. However an implicit call to
6503 -- an expression function may appear when it is part of a default
6504 -- expression in a call to an initialization procedure, and must be
6505 -- frozen now, even if the body is inserted at a later point.
6506 -- Otherwise, the call freezes the expression if expander is active,
6507 -- for example as part of an object declaration.
6510 and then not In_Spec_Expression
6513 and then Is_Expression_Function_Or_Completion
6515 and then
6518 then
6521 -- Force freeze of expression function in call
6530 -- For a predefined operator, the type of the result is the type imposed
6531 -- by context, except for a predefined operation on universal fixed.
6532 -- Otherwise the type of the call is the type returned by the subprogram
6533 -- being called.
6540 -- If the subprogram returns an array type, and the context requires the
6541 -- component type of that array type, the node is really an indexing of
6542 -- the parameterless call. Resolve as such. A pathological case occurs
6543 -- when the type of the component is an access to the array type. In
6544 -- this case the call is truly ambiguous. If the call is to an intrinsic
6545 -- subprogram, it can't be an indexed component. This check is necessary
6546 -- because if it's Unchecked_Conversion, and we have "type T_Ptr is
6547 -- access T;" and "type T is array (...) of T_Ptr;" (i.e. an array of
6548 -- pointers to the same array), the compiler gets confused and does an
6549 -- infinite recursion.
6552 and then
6555 or else
6558 and then
6561 then
6562 declare
6567 begin
6568 -- If this is a parameterless call there is no ambiguity and the
6569 -- call has the type of the function.
6578 -- Annotate the tree by creating a call marker in case the
6579 -- original call is transformed by expansion. The call marker
6580 -- is automatically saved for later examination by the ABE
6581 -- Processing phase.
6588 then
6589 Error_Msg_N
6591 else
6594 -- The called entity may be an explicit dereference, in which
6595 -- case there is no entity to set.
6603 or else
6605 and then
6607 then
6610 -- Indexed call to a parameterless function
6612 Index_Node :=
6614 Prefix =>
6617 else
6618 -- An Ada 2005 prefixed call to a primitive operation
6619 -- whose first parameter is the prefix. This prefix was
6620 -- prepended to the parameter list, which is actually a
6621 -- list of indexes. Remove the prefix in order to build
6622 -- the proper indexed component.
6624 Index_Node :=
6626 Prefix =>
6629 Parameter_Associations =>
6630 New_List
6635 -- Preserve the parenthesis count of the node
6639 -- Since we are correcting a node classification error made
6640 -- by the parser, we call Replace rather than Rewrite.
6651 -- Annotate the tree by creating a call marker in case
6652 -- the original call is transformed by expansion. The call
6653 -- marker is automatically saved for later examination by
6654 -- the ABE Processing phase.
6665 else
6666 -- If the called function is not declared in the main unit and it
6667 -- returns the limited view of type then use the available view (as
6668 -- is done in Try_Object_Operation) to prevent back-end confusion;
6669 -- for the function entity itself. The call must appear in a context
6670 -- where the nonlimited view is available. If the function entity is
6671 -- in the extended main unit then no action is needed, because the
6672 -- back end handles this case. In either case the type of the call
6673 -- is the nonlimited view.
6677 then
6684 else
6689 -- In the case where the call is to an overloaded subprogram, Analyze
6690 -- calls Normalize_Actuals once per overloaded subprogram. Therefore in
6691 -- such a case Normalize_Actuals needs to be called once more to order
6692 -- the actuals correctly. Otherwise the call will have the ordering
6693 -- given by the last overloaded subprogram whether this is the correct
6694 -- one being called or not.
6701 -- In any case, call is fully resolved now. Reset Overload flag, to
6702 -- prevent subsequent overload resolution if node is analyzed again
6707 -- A Ghost entity must appear in a specific context
6714 Local_Restrict.Check_Call
6716 else
6720 -- If we are calling the current subprogram from immediately within its
6721 -- body, then that is the case where we can sometimes detect cases of
6722 -- infinite recursion statically. Do not try this in case restriction
6723 -- No_Recursion is in effect anyway, and do it only for source calls.
6728 -- Issue warning for possible infinite recursion in the absence
6729 -- of the No_Recursion restriction.
6735 then
6736 -- Here we detected and flagged an infinite recursion, so we do
6737 -- not need to test the case below for further warnings. Also we
6738 -- are all done if we now have a raise SE node.
6744 -- If call is to immediately containing subprogram, then check for
6745 -- the case of a possible run-time detectable infinite recursion.
6747 else
6751 -- Ada 2022 (AI12-0075): Static functions are never allowed
6752 -- to make a recursive call, as specified by 6.8(5.4/5).
6755 Error_Msg_N
6764 -- Although in general case, recursion is not statically
6765 -- checkable, the case of calling an immediately containing
6766 -- subprogram is easy to catch.
6772 -- If the recursive call is to a parameterless subprogram,
6773 -- then even if we can't statically detect infinite
6774 -- recursion, this is pretty suspicious, and we output a
6775 -- warning. Furthermore, we will try later to detect some
6776 -- cases here at run time by expanding checking code (see
6777 -- Detect_Infinite_Recursion in package Exp_Ch6).
6779 -- If the recursive call is within a handler, do not emit a
6780 -- warning, because this is a common idiom: loop until input
6781 -- is correct, catch illegal input in handler and restart.
6787 then
6788 -- For the case of a procedure call. We give the message
6789 -- only if the call is the first statement in a sequence
6790 -- of statements, or if all previous statements are
6791 -- simple assignments. This is simply a heuristic to
6792 -- decrease false positives, without losing too many good
6793 -- warnings. The idea is that these previous statements
6794 -- may affect global variables the procedure depends on.
6795 -- We also exclude raise statements, that may arise from
6796 -- constraint checks and are probably unrelated to the
6797 -- intended control flow.
6801 then
6802 declare
6804 begin
6808 | N_Raise_Constraint_Error
6809 then
6818 -- Do not give warning if we are in a conditional context
6820 declare
6822 begin
6828 then
6833 -- Here warning is to be issued
6849 -- Check obsolescent reference to Ada.Characters.Handling subprogram
6853 -- If subprogram name is a predefined operator, it was given in
6854 -- functional notation. Replace call node with operator node, so
6855 -- that actuals can be resolved appropriately.
6867 -- Create a transient scope if the expander is active and the resulting
6868 -- type requires it.
6870 -- There are several notable exceptions:
6872 -- a) Intrinsic subprograms (Unchecked_Conversion and source info
6873 -- functions) do not use the secondary stack even though the return
6874 -- type may be unconstrained.
6876 -- b) Subprograms that are ignored ghost entities do not return anything
6878 -- c) Calls to a build-in-place function, since such functions may
6879 -- allocate their result directly in a target object, and cases where
6880 -- the result does get allocated in the secondary stack are checked for
6881 -- within the specialized Exp_Ch6 procedures for expanding those
6882 -- build-in-place calls.
6884 -- d) Calls to inlinable expression functions do not use the secondary
6885 -- stack (since the call will be replaced by its returned object).
6887 -- e) If the subprogram is marked Inline, then even if it returns
6888 -- an unconstrained type the call does not require use of the secondary
6889 -- stack. However, inlining will only take place if the body to inline
6890 -- is already present. It may not be available if e.g. the subprogram is
6891 -- declared in a child instance.
6893 -- f) If the subprogram is a static expression function and the call is
6894 -- a static call (the actuals are all static expressions), then we never
6895 -- want to create a transient scope (this could occur in the case of a
6896 -- static string-returning call).
6898 -- g) If the call is the expression of a simple return statement that
6899 -- returns on the same stack, since it will be handled as a tail call
6900 -- by Expand_Simple_Function_Return.
6902 if Expander_Active
6912 N_Subprogram_Declaration
6913 and then
6917 and then
6918 Needs_Secondary_Stack
6919 (Etype
6920 (Return_Applies_To
6923 then
6926 -- If the call appears within the bounds of a loop, it will be
6927 -- rewritten and reanalyzed, nothing left to do here.
6934 -- A protected function cannot be called within the definition of the
6935 -- enclosing protected type, unless it is part of a pre/postcondition
6936 -- on another protected operation. This may appear in the entry wrapper
6937 -- created for an entry with preconditions.
6942 and then not In_Spec_Expression
6944 then
6945 Error_Msg_NE
6949 -- Propagate interpretation to actuals, and add default expressions
6950 -- where needed.
6955 -- Overloaded literals are rewritten as function calls, for purpose of
6956 -- resolution. After resolution, we can replace the call with the
6957 -- literal itself.
6963 -- Avoid validation, since it is a static function call
6969 -- If the subprogram is not global, then kill all saved values and
6970 -- checks. This is a bit conservative, since in many cases we could do
6971 -- better, but it is not worth the effort. Similarly, we kill constant
6972 -- values. However we do not need to do this for internal entities
6973 -- (unless they are inherited user-defined subprograms), since they
6974 -- are not in the business of molesting local values.
6976 -- If the flag Suppress_Value_Tracking_On_Calls is set, then we also
6977 -- kill all checks and values for calls to global subprograms. This
6978 -- takes care of the case where an access to a local subprogram is
6979 -- taken, and could be passed directly or indirectly and then called
6980 -- from almost any context.
6982 -- Note: we do not do this step till after resolving the actuals. That
6983 -- way we still take advantage of the current value information while
6984 -- scanning the actuals.
6986 -- We suppress killing values if we are processing the nodes associated
6987 -- with N_Freeze_Entity nodes. Otherwise the declaration of a tagged
6988 -- type kills all the values as part of analyzing the code that
6989 -- initializes the dispatch tables.
6993 or else Suppress_Value_Tracking_On_Call
6998 then
6999 Kill_Current_Values;
7002 -- If we are warning about unread OUT parameters, this is the place to
7003 -- set Last_Assignment for OUT and IN OUT parameters. We have to do this
7004 -- after the above call to Kill_Current_Values (since that call clears
7005 -- the Last_Assignment field of all local variables).
7010 then
7011 declare
7015 begin
7025 then
7035 -- If the subprogram is a primitive operation, check whether or not
7036 -- it is a correct dispatching call.
7041 -- If the subprogram is an abstract operation, then flag an error
7047 -- If this is a dispatching call, generate the appropriate reference,
7048 -- for better source navigation in GNAT Studio.
7053 -- Normal case, not a dispatching call: generate a call reference
7055 else
7063 -- Check for violation of restriction No_Specific_Termination_Handlers
7064 -- and warn on a potentially blocking call to Abort_Task.
7068 or else
7070 then
7077 -- A call to Ada.Real_Time.Timing_Events.Set_Handler to set a relative
7078 -- timing event violates restriction No_Relative_Delay (AI-0211). We
7079 -- need to check the second argument to determine whether it is an
7080 -- absolute or relative timing event.
7085 then
7089 -- Issue an error for a call to an eliminated subprogram. This routine
7090 -- will not perform the check if the call appears within a default
7091 -- expression.
7095 -- Implement rule in 12.5.1 (23.3/2): In an instance, if the actual is
7096 -- class-wide and the call dispatches on result in a context that does
7097 -- not provide a tag, the call raises Program_Error.
7100 and then In_Instance
7105 then
7106 -- Verify that none of the formals are controlling
7108 declare
7112 begin
7134 -- Check for calling a function with OUT or IN OUT parameter when the
7135 -- calling context (us right now) is not Ada 2012, so does not allow
7136 -- OUT or IN OUT parameters in function calls. Functions declared in
7137 -- a predefined unit are OK, as they may be called indirectly from a
7138 -- user-declared instantiation.
7144 then
7149 -- Check the dimensions of the actuals in the call. For function calls,
7150 -- propagate the dimensions from the returned type to N.
7154 -- Check unreachable code after calls to procedures with No_Return
7160 -- All done, evaluate call and deal with elaboration issues
7168 -- Annotate the tree by creating a call marker in case the original call
7169 -- is transformed by expansion. The call marker is automatically saved
7170 -- for later examination by the ABE Processing phase.
7178 -- Ada 2022 (AI12-0075): If the call is a static call to a static
7179 -- expression function, then we want to "inline" the call, replacing
7180 -- it with the folded static result. This is not done if the checking
7181 -- for a potentially static expression is enabled or if an error has
7182 -- been posted on the call (which may be due to the check for recursive
7183 -- calls, in which case we don't want to fall into infinite recursion
7184 -- when doing the inlining).
7186 if not Checking_Potentially_Static_Expression
7190 then
7193 -- In GNATprove mode, expansion is disabled, but we want to inline some
7194 -- subprograms to facilitate formal verification. Indirect calls through
7195 -- a subprogram type or within a generic cannot be inlined. Inlining is
7196 -- performed only for calls subject to SPARK_Mode => On.
7198 elsif GNATprove_Mode
7201 and then not Inside_A_Generic
7202 then
7209 -- Nothing to do if the subprogram is not inlined (because it is
7210 -- recursive, directly or indirectly), or is not eligible for
7211 -- inlining GNATprove mode (because of properties of the
7212 -- subprogram itself), or inlining has been disabled with switch
7213 -- -gnatdm.
7217 or else Debug_Flag_M
7218 then
7221 -- Calls cannot be inlined inside assertions, as GNATprove treats
7222 -- assertions as logic expressions. Only issue a message when the
7223 -- body has been seen, otherwise this leads to spurious messages
7224 -- on expression functions.
7227 Cannot_Inline
7231 -- Calls cannot be inlined inside default expressions
7234 Cannot_Inline
7237 -- Calls cannot be inlined inside potentially unevaluated
7238 -- expressions, as this would create complex actions inside
7239 -- expressions, that are not handled by GNATprove.
7242 Cannot_Inline
7246 -- Calls are not inlined inside the loop_parameter_specification
7247 -- or iterator_specification of the quantified expression, as they
7248 -- are only preanalyzed. Calls in the predicate part are handled
7249 -- by the previous test on potentially unevaluated expressions.
7252 Cannot_Inline
7255 -- Inlining should not be performed during preanalysis
7259 -- Do not inline calls inside expression functions or functions
7260 -- generated by the front end for subtype predicates, as this
7261 -- would prevent interpreting them as logical formulas in
7262 -- GNATprove. Only issue a message when the body has been seen,
7263 -- otherwise this leads to spurious messages on callees that
7264 -- are themselves expression functions.
7267 and then
7272 then
7273 declare
7277 begin
7279 Cannot_Inline
7284 Cannot_Inline
7289 Cannot_Inline
7293 else
7294 Cannot_Inline
7300 -- Cannot inline a call inside the definition of a record type,
7301 -- typically inside the constraints of the type. Calls in
7302 -- default expressions are also not inlined, but this is
7303 -- filtered out above when testing In_Default_Expr.
7306 Cannot_Inline
7309 -- With the one-pass inlining technique, a call cannot be
7310 -- inlined if the corresponding body has not been seen yet.
7313 Cannot_Inline
7316 -- Nothing to do if there is no body to inline, indicating that
7317 -- the subprogram is not suitable for inlining in GNATprove
7318 -- mode.
7323 -- Calls cannot be inlined inside the conditions of while
7324 -- loops, as this would create complex actions inside
7325 -- the condition, that are not handled by GNATprove.
7328 Cannot_Inline
7331 -- Do not inline calls which would possibly lead to missing a
7332 -- type conversion check on an input parameter.
7335 Cannot_Inline
7339 -- Otherwise, inline the call, issuing an info message when
7340 -- -gnatd_f is set.
7342 else
7344 Error_Msg_NE
7355 -----------------------------
7356 -- Resolve_Case_Expression --
7357 -----------------------------
7365 begin
7379 -- When the expression is of a scalar subtype different from the
7380 -- result subtype, then insert a conversion to ensure the generation
7381 -- of a constraint check.
7391 -- Apply RM 4.5.7 (17/3): whether the expression is statically or
7392 -- dynamically tagged must be known statically.
7400 Error_Msg_N
7414 -------------------------------
7415 -- Resolve_Character_Literal --
7416 -------------------------------
7422 begin
7423 -- Verify that the character does belong to the type of the context
7428 -- Wide_Wide_Character literals must always be defined, since the set
7429 -- of wide wide character literals is complete, i.e. if a character
7430 -- literal is accepted by the parser, then it is OK for wide wide
7431 -- character (out of range character literals are rejected).
7436 -- Always accept character literal for type Any_Character, which
7437 -- occurs in error situations and in comparisons of literals, both
7438 -- of which should accept all literals.
7443 -- For Standard.Character or a type derived from it, check that the
7444 -- literal is in range.
7451 -- For Standard.Wide_Character or a type derived from it, check that the
7452 -- literal is in range.
7459 -- If the entity is already set, this has already been resolved in a
7460 -- generic context, or comes from expansion. Nothing else to do.
7465 -- Otherwise we have a user defined character type, and we can use the
7466 -- standard visibility mechanisms to locate the referenced entity.
7468 else
7481 -- If we fall through, then the literal does not match any of the
7482 -- entries of the enumeration type. This isn't just a constraint error
7483 -- situation, it is an illegality (see RM 4.2).
7485 Error_Msg_NE
7489 ---------------------------
7490 -- Resolve_Comparison_Op --
7491 ---------------------------
7493 -- The operands must have compatible types and the boolean context does not
7494 -- participate in the resolution. The first pass verifies that the operands
7495 -- are not ambiguous and sets their type correctly, or to Any_Type in case
7496 -- of ambiguity. If both operands are strings or aggregates, then they are
7497 -- ambiguous even if they carry a single (universal) type.
7505 begin
7514 -- Deal with explicit ambiguity of operands
7523 -- Deal with other error cases
7527 T = Any_Character
7528 then
7531 else
7539 -- Resolve the operands if types OK
7549 -- Check comparison on unordered enumeration
7553 Error_Msg_NE
7563 --------------------------------
7564 -- Resolve_Declare_Expression --
7565 --------------------------------
7567 procedure Resolve_Declare_Expression
7570 is
7577 -- Use a tree traversal to replace each occurrence of the name of
7578 -- a local object declared in the construct, with the corresponding
7579 -- entity. This replaces the usual way to perform name capture by
7580 -- visibility, because it is not possible to place on the scope
7581 -- stack the fake scope created for the analysis of the local
7582 -- declarations; such a scope conflicts with the transient scopes
7583 -- that may be generated if the expression includes function calls
7584 -- requiring finalization.
7586 -------------------
7587 -- Replace_Local --
7588 -------------------
7591 begin
7592 -- The identifier may be the prefix of a selected component,
7593 -- but not a selector name, because the local entities do not
7594 -- have a scope that can be named: a selected component whose
7595 -- selector is a homonym of a local entity must denote some
7596 -- global entity.
7601 and then
7604 then
7614 -- Start of processing for Resolve_Declare_Expression
7616 begin
7622 N_Object_Declaration | N_Object_Renaming_Declaration
7624 then
7628 -- Traverse the expression to replace references to local
7629 -- variables that occur within declarations of the
7630 -- declare_expression.
7632 declare
7634 begin
7645 -- The end of the declarative list is a freeze point for the
7646 -- local declarations.
7657 -----------------------------------
7658 -- Resolve_Dependent_Expression --
7659 -----------------------------------
7661 procedure Resolve_Dependent_Expression
7665 is
7666 begin
7667 -- RM 4.5.7(8/3) says that the expected type of dependent expressions is
7668 -- that of the conditional expression but RM 4.5.7(10/3) forces the type
7669 -- of the conditional expression without changing the expected type (the
7670 -- expected type of the operand of a type conversion is any type), so we
7671 -- may have a gap between these two types that is bridged by the dynamic
7672 -- semantics specified by RM 4.5.7(20/3) with the associated legality
7673 -- rule RM 4.5.7(16/3) that will be automatically enforced.
7677 then
7680 else
7685 -----------------------------------------
7686 -- Resolve_Discrete_Subtype_Indication --
7687 -----------------------------------------
7689 procedure Resolve_Discrete_Subtype_Indication
7692 is
7696 begin
7704 else
7714 Error_Msg_NE
7717 -- Rewrite the constraint as a range of Typ
7718 -- to allow compilation to proceed further.
7730 else
7734 -- Additionally, we must check that the bounds are compatible
7735 -- with the given subtype, which might be different from the
7736 -- type of the context.
7740 -- ??? If the above check statically detects a Constraint_Error
7741 -- it replaces the offending bound(s) of the range R with a
7742 -- Constraint_Error node. When the itype which uses these bounds
7743 -- is frozen the resulting call to Duplicate_Subexpr generates
7744 -- a new temporary for the bounds.
7746 -- Unfortunately there are other itypes that are also made depend
7747 -- on these bounds, so when Duplicate_Subexpr is called they get
7748 -- a forward reference to the newly created temporaries and Gigi
7749 -- aborts on such forward references. This is probably sign of a
7750 -- more fundamental problem somewhere else in either the order of
7751 -- itype freezing or the way certain itypes are constructed.
7753 -- To get around this problem we call Remove_Side_Effects right
7754 -- away if either bounds of R are a Constraint_Error.
7756 declare
7760 begin
7776 -------------------------
7777 -- Resolve_Entity_Name --
7778 -------------------------
7780 -- Used to resolve identifiers and expanded names
7783 function Is_Assignment_Or_Object_Expression
7786 -- Determine whether node Context denotes an assignment statement or an
7787 -- object declaration whose expression is node Expr.
7790 -- Determine whether Expr is part of an N_Attribute_Reference
7791 -- expression.
7793 ----------------------------------------
7794 -- Is_Assignment_Or_Object_Expression --
7795 ----------------------------------------
7797 function Is_Assignment_Or_Object_Expression
7800 is
7801 begin
7804 then
7807 -- Check whether a construct that yields a name is the expression of
7808 -- an assignment statement or an object declaration.
7811 | N_Explicit_Dereference
7812 | N_Indexed_Component
7813 | N_Selected_Component
7814 | N_Slice
7816 or else
7818 | N_Unchecked_Type_Conversion
7820 then
7821 return
7822 Is_Assignment_Or_Object_Expression
7826 -- Otherwise the context is not an assignment statement or an object
7827 -- declaration.
7829 else
7834 -----------------------------
7835 -- Is_Attribute_Expression --
7836 -----------------------------
7840 begin
7845 -- Prevent the search from going too far
7857 -- Local variables
7862 -- Start of processing for Resolve_Entity_Name
7864 begin
7865 -- If garbage from errors, set to Any_Type and return
7872 -- Replace named numbers by corresponding literals. Note that this is
7873 -- the one case where Resolve_Entity_Name must reset the Etype, since
7874 -- it is currently marked as universal.
7884 -- For enumeration literals, we need to make sure that a proper style
7885 -- check is done, since such literals are overloaded, and thus we did
7886 -- not do a style check during the first phase of analysis.
7892 -- Case of (sub)type name appearing in a context where an expression
7893 -- is expected. This is legal if occurrence is a current instance.
7894 -- See RM 8.6 (17/3). It is also legal if the expression is
7895 -- part of a choice pattern for a case stmt/expr having a
7896 -- non-discrete selecting expression.
7902 -- Any other use is an error
7904 else
7905 Error_Msg_N
7909 -- Check discriminant use if entity is discriminant in current scope,
7910 -- i.e. discriminant of record or concurrent type currently being
7911 -- analyzed. Uses in corresponding body are unrestricted.
7916 then
7919 -- A parameterless generic function cannot appear in a context that
7920 -- requires resolution.
7925 -- In Ada 83 an OUT parameter cannot be read, but attributes of
7926 -- array types (i.e. bounds and length) are legal.
7934 or else Is_Assignment_Or_Object_Expression
7937 then
7942 -- In all other cases, just do the possible static evaluation
7944 else
7945 -- A deferred constant that appears in an expression must have a
7946 -- completion, unless it has been removed by in-place expansion of
7947 -- an aggregate. A constant that is a renaming does not need
7948 -- initialization.
7954 and then not In_Spec_Expression
7957 then
7961 then
7963 else
7964 Error_Msg_N
7974 -- When the entity appears in a parameter association, retrieve the
7975 -- related subprogram call.
7983 -- The following checks are only relevant when SPARK_Mode is On as
7984 -- they are not standard Ada legality rules.
7988 -- Check for possible elaboration issues with respect to reads of
7989 -- variables. The act of renaming the variable is not considered a
7990 -- read as it simply establishes an alias.
7992 if Legacy_Elaboration_Checks
7994 and then Dynamic_Elaboration_Checks
7996 then
8001 -- The variable may eventually become a constituent of a single
8002 -- protected/task type. Record the reference now and verify its
8003 -- legality when analyzing the contract of the variable
8004 -- (SPARK RM 9.3).
8010 -- A Ghost entity must appear in a specific context
8016 -- We may be resolving an entity within expanded code, so a reference
8017 -- to an entity should be ignored when calculating effective use
8018 -- clauses to avoid inappropriate marking.
8024 -------------------
8025 -- Resolve_Entry --
8026 -------------------
8038 -- If the bounds of the entry family being called depend on task
8039 -- discriminants, build a new index subtype where a discriminant is
8040 -- replaced with the value of the discriminant of the target task.
8041 -- The target task is the prefix of the entry name in the call.
8043 -----------------------
8044 -- Actual_Index_Type --
8045 -----------------------
8055 -- If the bound is given by a discriminant, replace with a reference
8056 -- to the discriminant of the same name in the target task. If the
8057 -- entry name is the target of a requeue statement and the entry is
8058 -- in the current protected object, the bound to be used is the
8059 -- discriminal of the object (see Apply_Range_Check for details of
8060 -- the transformation).
8062 -----------------------------
8063 -- Actual_Discriminant_Ref --
8064 -----------------------------
8070 begin
8075 then
8081 then
8082 -- Note: here Bound denotes a discriminant of the corresponding
8083 -- record type tskV, whose discriminal is a formal of the
8084 -- init-proc tskVIP. What we want is the body discriminal,
8085 -- which is associated to the discriminant of the original
8086 -- concurrent type tsk.
8088 return New_Occurrence_Of
8091 else
8092 Ref :=
8102 -- Start of processing for Actual_Index_Type
8104 begin
8107 then
8110 else
8124 -- Start of processing for Resolve_Entry
8126 begin
8127 -- Find name of entry being called, and resolve prefix of name with its
8128 -- own type. The prefix can be overloaded, and the name and signature of
8129 -- the entry must be taken into account.
8133 -- Case of dealing with entry family within the current tasks
8137 else
8143 -- Entry call to an entry (or entry family) in the current task. This
8144 -- is legal even though the task will deadlock. Rewrite as call to
8145 -- current task.
8147 -- This can also be a call to an entry in an enclosing task. If this
8148 -- is a single task, we have to retrieve its name, because the scope
8149 -- of the entry is the task type, not the object. If the enclosing
8150 -- task is a task type, the identity of the task is given by its own
8151 -- self variable.
8153 -- Finally this can be a requeue on an entry of the same task or
8154 -- protected object.
8161 then
8162 -- S is an enclosing task or protected object. The concurrent
8163 -- declaration has been converted into a type declaration, and
8164 -- the object itself has an object declaration that follows
8165 -- the type in the same declarative part.
8177 -- Call to current task. Will be transformed into call to Self
8184 New_N :=
8187 Selector_Name =>
8194 then
8195 -- Use the entry name (which must be unique at this point) to find
8196 -- the prefix that returns the corresponding task/protected type.
8198 declare
8204 begin
8226 -- We do not resolve the prefix because an Entry_Family has no type,
8227 -- although it has the semantics of an array since it can be indexed.
8228 -- In order to perform the associated range check, we would need to
8229 -- build an array type on the fly and set it on the prefix, but this
8230 -- would be wasteful since only the index type matters. Therefore we
8231 -- attach this index type directly, so that Actual_Index_Expression
8232 -- can pick it up later in order to generate the range check.
8239 -- Generate a reference for the index when it denotes an entity
8245 -- Up to this point the expression could have been the actual in a
8246 -- simple entry call, and be given by a named association.
8250 else
8256 ------------------------
8257 -- Resolve_Entry_Call --
8258 ------------------------
8269 begin
8270 -- We kill all checks here, because it does not seem worth the effort to
8271 -- do anything better, an entry call is a big operation.
8273 Kill_All_Checks;
8275 -- Processing of the name is similar for entry calls and protected
8276 -- operation calls. Once the entity is determined, we can complete
8277 -- the resolution of the actuals.
8279 -- The selector may be overloaded, in the case of a protected object
8280 -- with overloaded functions. The type of the context is used for
8281 -- resolution.
8286 then
8287 declare
8291 begin
8310 -- Simple entry or protected operation call
8323 -- Call to member of entry family
8330 -- We cannot in general check the maximum depth of protected entry calls
8331 -- at compile time. But we can tell that any protected entry call at all
8332 -- violates a specified nesting depth of zero.
8338 -- Use context type to disambiguate a protected function that can be
8339 -- called without actuals and that returns an array type, and where the
8340 -- argument list may be an indexing of the returned value.
8345 and then
8351 and then
8352 Covers
8355 then
8356 declare
8359 begin
8360 Index_Node :=
8362 Prefix =>
8366 -- Since we are correcting a node classification error made by the
8367 -- parser, we call Replace rather than Rewrite.
8381 then
8382 -- Note the entity being called before rewriting the call, so that
8383 -- it appears used at this point.
8387 -- Rewrite as call to the precondition wrapper, adding the task
8388 -- object to the list of actuals. If the call is to a member of an
8389 -- entry family, include the index as well.
8391 declare
8395 begin
8404 New_Call :=
8406 Name =>
8411 -- Preanalyze and resolve new call. Current procedure is called
8412 -- from Resolve_Call, after which expansion will take place.
8419 -- The operation name may have been overloaded. Order the actuals
8420 -- according to the formals of the resolved entity, and set the return
8421 -- type to that of the operation.
8428 -- Reset the Is_Overloaded flag, since resolution is now completed
8430 -- Simple entry call
8435 -- Call to a member of an entry family
8445 -- Create a call reference to the entry
8453 -- Verify that a procedure call cannot masquerade as an entry
8454 -- call where an entry call is expected.
8459 then
8464 then
8469 then
8474 -- After resolution, entry calls and protected procedure calls are
8475 -- changed into entry calls, for expansion. The structure of the node
8476 -- does not change, so it can safely be done in place. Protected
8477 -- function calls must keep their structure because they are
8478 -- subexpressions.
8482 -- A protected operation that is not a function may modify the
8483 -- corresponding object, and cannot apply to a constant. If this
8484 -- is an internal call, the prefix is the type itself.
8490 then
8491 Error_Msg_N
8493 Entry_Name);
8496 declare
8499 begin
8500 Entry_Call :=
8505 -- Inherit relevant attributes from the original call
8507 Set_First_Named_Actual
8510 Set_Is_Elaboration_Checks_OK_Node
8513 Set_Is_Elaboration_Warnings_OK_Node
8516 Set_Is_SPARK_Mode_On_Node
8523 -- Protected functions can return on the secondary stack, in which case
8524 -- we must trigger the transient scope mechanism.
8526 elsif Expander_Active
8528 then
8532 -- Now we know that this is not a call to a function that returns an
8533 -- array type; moreover, we know the name of the called entry. Detect
8534 -- overlapping actuals, just like for a subprogram call.
8539 -------------------------
8540 -- Resolve_Equality_Op --
8541 -------------------------
8543 -- The operands must have compatible types and the boolean context does not
8544 -- participate in the resolution. The first pass verifies that the operands
8545 -- are not ambiguous and sets their type correctly, or to Any_Type in case
8546 -- of ambiguity. If both operands are strings, aggregates, allocators, or
8547 -- null, they are ambiguous even if they carry a single (universal) type.
8557 and then not
8559 -- Whether this is a call to the implicit inequality operator created
8560 -- for a user-defined operator that is not an intrinsic subprogram, in
8561 -- which case we need to skip some processing.
8566 -- For any object, '[Unchecked_]Access of such object can never be
8567 -- passed as an operand to the Universal_Access equality operators.
8568 -- This is so because the expected type for Obj'Access in a call to
8569 -- these operators, whose formals are of type Universal_Access, is
8570 -- Universal_Access, and Universal_Access does not have a designated
8571 -- type. For more details, see RM 3.10.2(2/2) and 6.4.1(3).
8574 -- Check RM 4.5.2(9.6/2) on the given designated object types
8577 -- Check RM 4.5.2(9.7/2) on the given designated subprogram types
8580 -- The resolution rule for if expressions requires that each such must
8581 -- have a unique type. This means that if several dependent expressions
8582 -- are of a non-null anonymous access type, and the context does not
8583 -- impose an expected type (as can be the case in an equality operation)
8584 -- the expression must be rejected.
8587 -- Attempt to explain the nature of a redundant comparison with True. If
8588 -- the expression N is too complex, this routine issues a general error
8589 -- message.
8592 -- In the case of allocators and access attributes, the context must
8593 -- provide an indication of the specific access type to be used. If
8594 -- one operand is of such a "generic" access type, check whether there
8595 -- is a specific visible access type that has the same designated type.
8596 -- This is semantically dubious, and of no interest to any real code,
8597 -- but c48008a makes it all worthwhile.
8600 -- Returns True iff the parent node is a and/or/xor operation that
8601 -- could be the cause of confused priorities. Note that if the not is
8602 -- in parens, then False is returned.
8604 ----------------------------
8605 -- Check_Access_Attribute --
8606 ----------------------------
8609 begin
8612 then
8613 Error_Msg_N
8619 -----------------------------------
8620 -- Check_Designated_Object_Types --
8621 -----------------------------------
8624 begin
8628 then
8629 Error_Msg_N
8637 ---------------------------------------
8638 -- Check_Designated_Subprogram_Types --
8639 ---------------------------------------
8642 begin
8644 Error_Msg_N
8652 -------------------------
8653 -- Check_If_Expression --
8654 -------------------------
8660 begin
8667 then
8673 ------------------------
8674 -- Explain_Redundancy --
8675 ------------------------
8682 begin
8685 -- Strip the operand down to an entity
8687 loop
8690 else
8695 -- The construct denotes an entity
8700 -- Do not generate an error message when the comparison is done
8701 -- against the enumeration literal Standard.True.
8705 -- Build a customized error message
8732 -- The construct is too complex to disect, issue a general message
8734 else
8739 -----------------------------
8740 -- Find_Unique_Access_Type --
8741 -----------------------------
8748 begin
8750 then
8754 then
8756 else
8768 then
8781 ----------------------------------
8782 -- Suspicious_Prio_For_Equality --
8783 ----------------------------------
8788 begin
8789 -- Check if parent node is one of and/or/xor, not parenthesized
8790 -- explicitly, and its own parent is not of this kind. Otherwise,
8791 -- it's a case of chained Boolean conditions which is likely well
8792 -- parenthesized.
8797 then
8798 declare
8802 else
8804 begin
8805 -- Compar may have been rewritten, for example from (a /= b)
8806 -- into not (a = b). Use the Original_Node instead.
8810 -- If the other argument of the and/or/xor is also a
8811 -- comparison, or another and/or/xor then most likely
8812 -- the priorities are correctly set.
8817 else
8822 -- Start of processing for Resolve_Equality_Op
8824 begin
8833 -- Deal with explicit ambiguity of operands, unless this is a call
8834 -- to the implicit inequality operator created for a user-defined
8835 -- operator that is not an intrinsic subprogram, since the common
8836 -- resolution of operands done here does not apply to it.
8838 if not Implicit_NE_For_User_Defined_Operator
8840 then
8844 else
8846 -- For Ada 2022, check for user-defined literals when the type has
8847 -- the appropriate aspect.
8859 -- Deal with other error cases
8863 T = Any_Character
8864 then
8867 else
8876 then
8885 -- If expressions must have a single type, and if the context does
8886 -- not impose one the dependent expressions cannot be anonymous
8887 -- access types.
8889 -- Why no similar processing for case expressions???
8894 then
8899 -- RM 4.5.2(9.5/2): At least one of the operands of the equality
8900 -- operators for universal_access shall be of type universal_access,
8901 -- or both shall be of access-to-object types, or both shall be of
8902 -- access-to-subprogram types (RM 4.5.2(9.5/2)).
8907 then
8908 -- RM 4.5.2(9.6/2): When both are of access-to-object types, the
8909 -- designated types shall be the same or one shall cover the other
8910 -- and if the designated types are elementary or array types, then
8911 -- the designated subtypes shall statically match.
8915 then
8916 Check_Designated_Object_Types
8919 -- RM 4.5.2(9.7/2): When both are of access-to-subprogram types,
8920 -- the designated profiles shall be subtype conformant.
8924 then
8925 Check_Designated_Subprogram_Types
8930 -- Check another case of equality operators for universal_access
8941 -- AI12-0413: user-defined primitive equality of an untagged record
8942 -- type hides the predefined equality operator, including within a
8943 -- generic, and if it is declared abstract, results in an illegal
8944 -- instance if the operator is used in the spec, or in the raising
8945 -- of Program_Error if used in the body of an instance.
8948 and then In_Instance
8950 then
8951 declare
8956 begin
8960 then
8966 else
8976 -- If the unique type is a class-wide type then it will be expanded
8977 -- into a dispatching call to the predefined primitive. Therefore we
8978 -- check here for potential violation of such restriction.
8984 -- Only warn for redundant equality comparison to True for objects
8985 -- (e.g. "X = True") and operations (e.g. "(X < Y) = True"). For
8986 -- other expressions, it may be a matter of preference to write
8987 -- "Expr = True" or "Expr".
8989 if Warn_On_Redundant_Constructs
8994 and then
8996 or else
8998 then
8999 Error_Msg_N -- CODEFIX
9004 -- Warn on a (in)equality between boolean values which is not
9005 -- parenthesized when the parent expression is one of and/or/xor, as
9006 -- this is interpreted as (a = b) op c where most likely a = (b op c)
9007 -- was intended. Do not generate a warning in generic instances, as
9008 -- the problematic expression may be implicitly parenthesized in
9009 -- the generic itself if one of the operators is a generic formal.
9010 -- Also do not generate a warning for generated equality, for
9011 -- example from rewritting a membership test.
9013 if Warn_On_Questionable_Missing_Parens
9014 and then not In_Instance
9017 and then Suspicious_Prio_For_Equality
9018 then
9027 -- Unless this is a call to the implicit inequality operator created
9028 -- for a user-defined operator that is not an intrinsic subprogram,
9029 -- try to fold the operation.
9037 then
9043 ----------------------------------
9044 -- Resolve_Explicit_Dereference --
9045 ----------------------------------
9053 -- The candidate prefix type, if overloaded
9058 begin
9062 -- A useful optimization: check whether the dereference denotes an
9063 -- element of a container, and if so rewrite it as a call to the
9064 -- corresponding Element function.
9066 -- Disabled for now, on advice of ARG. A more restricted form of the
9067 -- predicate might be acceptable ???
9069 -- if Is_Container_Element (N) then
9070 -- return;
9071 -- end if;
9075 -- Use the context type to select the prefix that has the correct
9076 -- designated type. Keep the first match, which will be the inner-
9077 -- most.
9084 then
9089 -- Remove access types that do not match, but preserve access
9090 -- to subprogram interpretations, in case a further dereference
9091 -- is needed (see below).
9104 else
9105 -- If no interpretation covers the designated type of the prefix,
9106 -- this is the pathological case where not all implementations of
9107 -- the prefix allow the interpretation of the node as a call. Now
9108 -- that the expected type is known, Remove other interpretations
9109 -- from prefix, rewrite it as a call, and resolve again, so that
9110 -- the proper call node is generated.
9121 New_N :=
9123 Name =>
9134 -- If not overloaded, resolve P with its own type
9136 else
9140 -- If the prefix might be null, add an access check
9144 then
9148 -- If the designated type is a packed unconstrained array type, and the
9149 -- explicit dereference is not in the context of an attribute reference,
9150 -- then we must compute and set the actual subtype, since it is needed
9151 -- by Gigi. The reason we exclude the attribute case is that this is
9152 -- handled fine by Gigi, and in fact we use such attributes to build the
9153 -- actual subtype. We also exclude generated code (which builds actual
9154 -- subtypes directly if they are needed).
9160 then
9166 -- Note: No Eval processing is required for an explicit dereference,
9167 -- because such a name can never be static.
9171 -------------------------------------
9172 -- Resolve_Expression_With_Actions --
9173 -------------------------------------
9178 -- True if Act is an action of a declare_expression that is allowed in a
9179 -- static declare_expression.
9182 -- True if all actions of N are allowed in a static declare_expression.
9185 -- Expr is an expression with compile-time-known value. This returns the
9186 -- literal node that reprsents that value.
9188 -------------------
9189 -- OK_For_Static --
9190 -------------------
9193 begin
9198 then
9208 -- No other declarations, nor even pragmas, are allowed in a
9209 -- declare expression, so if we see something else, it must be
9210 -- an internally generated expression_with_actions.
9217 -----------------------
9218 -- All_OK_For_Static --
9219 -----------------------
9223 begin
9235 -----------------
9236 -- Get_Literal --
9237 -----------------
9242 begin
9247 else
9256 pragma Assert
9262 -- Local variables
9266 -- Start of processing for Resolve_Expression_With_Actions
9268 begin
9275 -- If the value of the expression is known at compile time, and all
9276 -- of the actions (if any) are suitable, then replace the declare
9277 -- expression with its expression. This allows the declare expression
9278 -- as a whole to be static if appropriate. See AI12-0368.
9284 Rewrite
9291 ----------------------------------
9292 -- Resolve_Generalized_Indexing --
9293 ----------------------------------
9297 begin
9302 ---------------------------
9303 -- Resolve_If_Expression --
9304 ---------------------------
9310 -- When a dependent expression is of a subtype different from
9311 -- the context subtype, then insert a qualification to ensure
9312 -- the generation of a constraint check. This was previously
9313 -- for scalar types. For array types apply a length check, given
9314 -- that the context in general allows sliding, while a qualified
9315 -- expression forces equality of bounds.
9317 -----------------
9318 -- Apply_Check --
9319 -----------------
9325 begin
9330 or else Inside_A_Generic
9331 then
9337 else
9347 -- Local variables
9353 -- So in most cases the type of the if_expression and of its
9354 -- dependent expressions is that of the context. However, if
9355 -- the expression is the index of an Indexed_Component, we must
9356 -- ensure that a proper index check is applied, rather than a
9357 -- range check on the index type (which might be discriminant
9358 -- dependent). In this case we resolve with the base type of the
9359 -- index type, and the index check is generated in the resolution
9360 -- of the indexed_component above.
9362 -- Start of processing for Resolve_If_Expression
9364 begin
9365 -- Defend against malformed expressions
9374 then
9377 else
9397 -- If ELSE expression present, just resolve using the determined type
9405 -- Apply RM 4.5.7 (17/3): whether the expression is statically or
9406 -- dynamically tagged must be known statically.
9411 then
9417 -- If no ELSE expression is present, root type must be Standard.Boolean
9418 -- and we provide a Standard.True result converted to the appropriate
9419 -- Boolean type (in case it is a derived boolean type).
9422 Else_Expr :=
9427 else
9441 ----------------------------------
9442 -- Resolve_Implicit_Dereference --
9443 ----------------------------------
9448 begin
9456 -------------------------------
9457 -- Resolve_Indexed_Component --
9458 -------------------------------
9466 begin
9474 -- Use the context type to select the prefix that yields the correct
9475 -- component type.
9477 declare
9483 begin
9490 and then
9491 Covers
9494 then
9503 else
9509 else
9520 else
9527 -- If the prefix's type is an access type, get to the real array type.
9528 -- Note: we do not apply an access check because an explicit dereference
9529 -- will be introduced later, and the check will happen there.
9535 -- If name was overloaded, set component type correctly now.
9536 -- If a misplaced call to an entry family (which has no index types)
9537 -- return. Error will be diagnosed from calling context.
9541 else
9548 -- The prefix may have resolved to a string literal, in which case its
9549 -- etype has a special representation. This is only possible currently
9550 -- if the prefix is a static concatenation, written in functional
9551 -- notation.
9556 else
9571 -- Do not generate the warning on suspicious index if we are analyzing
9572 -- package Ada.Tags; otherwise we will report the warning with the
9573 -- Prims_Ptr field of the dispatch table.
9576 or else not
9578 then
9583 -- If the array type is atomic and the component is not, then this is
9584 -- worth a warning before Ada 2022, since we have a situation where the
9585 -- access to the component may cause extra read/writes of the atomic
9586 -- object, or partial word accesses, both of which may be unexpected.
9592 and then Has_Atomic_Components
9596 then
9597 Error_Msg_N
9599 Error_Msg_N
9604 -----------------------------
9605 -- Resolve_Integer_Literal --
9606 -----------------------------
9609 begin
9614 -----------------------------------------
9615 -- Resolve_Interpolated_String_Literal --
9616 -----------------------------------------
9619 is
9622 begin
9628 -- Resolve string elements using the context type; for interpolated
9629 -- expressions there is no need to check if their type has a suitable
9630 -- image function because under Ada 2022 all the types have such
9631 -- function available.
9643 --------------------------------
9644 -- Resolve_Intrinsic_Operator --
9645 --------------------------------
9652 -- True if this is the special mod operator of System.Storage_Elements,
9653 -- which needs to be resolved to the type of the left operand in order
9654 -- to implement the correct semantics.
9660 -- The base type to be used for the operator
9663 -- If the operand is a literal, it cannot be the expression in a
9664 -- conversion. Use a qualified expression instead.
9666 ---------------------
9667 -- Convert_Operand --
9668 ---------------------
9674 begin
9676 Res :=
9682 else
9689 -- Local variables
9695 -- Start of processing for Resolve_Intrinsic_Operator
9697 begin
9698 -- We must preserve the original entity in a generic setting, so that
9699 -- the legality of the operation can be verified in an instance.
9714 -- If the result or operand types are private, rewrite with unchecked
9715 -- conversions on the operands and the result, to expose the proper
9716 -- underlying numeric type. Likewise for the special mod operator of
9717 -- System.Storage_Elements, to expose the modified base type.
9722 or else Is_Stoele_Mod
9723 then
9728 else
9749 then
9750 -- Add explicit conversion where needed, and save interpretations in
9751 -- case operands are overloaded.
9758 else
9764 else
9774 else
9779 --------------------------------------
9780 -- Resolve_Intrinsic_Unary_Operator --
9781 --------------------------------------
9783 procedure Resolve_Intrinsic_Unary_Operator
9786 is
9791 begin
9810 else
9815 ------------------------
9816 -- Resolve_Logical_Op --
9817 ------------------------
9822 begin
9825 -- Predefined operations on scalar types yield the base type. On the
9826 -- other hand, logical operations on arrays yield the type of the
9827 -- arguments (and the context).
9831 else
9835 -- The following test is required because the operands of the operation
9836 -- may be literals, in which case the resulting type appears to be
9837 -- compatible with a signed integer type, when in fact it is compatible
9838 -- only with modular types. If the context itself is universal, the
9839 -- operation is illegal.
9847 Error_Msg_N
9855 then
9859 -- Replace AND by AND THEN, or OR by OR ELSE, if Short_Circuit_And_Or
9860 -- is active and the result type is standard Boolean (do not mess with
9861 -- ops that return a nonstandard Boolean type, because something strange
9862 -- is going on).
9864 -- Note: you might expect this replacement to be done during expansion,
9865 -- but that doesn't work, because when the pragma Short_Circuit_And_Or
9866 -- is used, no part of the right operand of an "and" or "or" operator
9867 -- should be executed if the left operand would short-circuit the
9868 -- evaluation of the corresponding "and then" or "or else". If we left
9869 -- the replacement to expansion time, then run-time checks associated
9870 -- with such operands would be evaluated unconditionally, due to being
9871 -- before the condition prior to the rewriting as short-circuit forms
9872 -- during expansion.
9874 if Short_Circuit_And_Or
9877 then
9878 -- Mark the corresponding putative SCO operator as truly a logical
9879 -- (and short-circuit) operator.
9892 -- Case of OR changed to OR ELSE
9894 else
9902 -- Return now, since analysis of the rewritten ops will take care of
9903 -- other reference bookkeeping and expression folding.
9919 ---------------------------------
9920 -- Resolve_Membership_Equality --
9921 ---------------------------------
9926 begin
9927 -- RM 4.5.2(4.1/3): if the type is limited, then it shall have a visible
9928 -- primitive equality operator. This means that we can use the regular
9929 -- visibility-based resolution and reset Entity in order to trigger it.
9934 -- RM 4.5.2(28.1/3): if the type is a record, then the membership test
9935 -- uses the primitive equality for the type [even if it is not visible].
9936 -- We only deal with the untagged case here, because the tagged case is
9937 -- handled uniformly in the expander.
9940 declare
9943 begin
9951 ---------------------------
9952 -- Resolve_Membership_Op --
9953 ---------------------------
9955 -- The context can only be a boolean type, and does not determine the
9956 -- arguments. Arguments should be unambiguous, but the preference rule for
9957 -- universal types applies.
9967 -- Analysis has determined a unique type for the left operand. Use it as
9968 -- the basis to resolve the disjuncts.
9970 ----------------------------
9971 -- Resolve_Set_Membership --
9972 ----------------------------
9977 begin
9978 -- If the left operand is overloaded, find type compatible with not
9979 -- overloaded alternative of the right operand.
9988 else
9993 -- Unclear how to resolve expression if all alternatives are also
9994 -- overloaded.
10000 else
10009 -- Alternative is an expression, a range
10010 -- or a subtype mark.
10014 then
10021 -- Check for duplicates for discrete case
10024 declare
10033 begin
10034 -- Loop checking duplicates. This is quadratic, but giant sets
10035 -- are unlikely in this context so it's a reasonable choice.
10042 | N_Character_Literal
10043 | N_Has_Entity
10044 then
10061 -- RM 4.5.2 (28.1/3) specifies that for types other than records or
10062 -- limited types, evaluation of a membership test uses the predefined
10063 -- equality for the type. This may be confusing to users, and the
10064 -- following warning appears useful for the most common case.
10068 then
10069 Error_Msg_NE
10071 Error_Msg_N
10076 -- Start of processing for Resolve_Membership_Op
10078 begin
10084 Resolve_Set_Membership;
10090 then
10093 -- If the left operand is of a universal numeric type and the right
10094 -- operand is not, we do not resolve the operands to the tested type
10095 -- but to the universal type instead. If not conforming to the letter,
10096 -- it's conforming to the spirit of the specification of membership
10097 -- tests, which are typically used to guard a specific operation and
10098 -- ought not to fail a check in doing so. Without this, in the case of
10100 -- type Small_Length is range 1 .. 16;
10102 -- function Is_Small_String (S : String) return Boolean is
10103 -- begin
10104 -- return S'Length in Small_Length;
10105 -- end;
10107 -- the function Is_Small_String would fail a range check for strings
10108 -- larger than 127 characters.
10110 -- The test on the size is required in GNAT because universal_integer
10111 -- does not cover all the values of all the supported integer types,
10112 -- for example the large values of Long_Long_Long_Unsigned.
10117 or else
10119 and then
10121 or else
10123 then
10126 -- If the right operand is 'Range, we first need to resolve it (to
10127 -- the tested type) so that it is rewritten as an N_Range, before
10128 -- converting its bounds and resolving it again below.
10132 then
10136 -- If the right operand is an N_Range, we convert its bounds to the
10137 -- universal type before resolving it.
10147 -- Ada 2005 (AI-251): Support the following case:
10149 -- type I is interface;
10150 -- type T is tagged ...
10152 -- function Test (O : I'Class) is
10153 -- begin
10154 -- return O in T'Class.
10155 -- end Test;
10157 -- In this case we have nothing else to do. The membership test will be
10158 -- done at run time.
10164 then
10167 else
10171 -- If mixed-mode operations are present and operands are all literal,
10172 -- the only interpretation involves Duration, which is probably not
10173 -- the intention of the programmer.
10188 then
10194 else
10199 -- Here after resolving membership operation
10206 ------------------
10207 -- Resolve_Null --
10208 ------------------
10213 begin
10214 -- Handle restriction against anonymous null access values This
10215 -- restriction can be turned off using -gnatdj.
10217 -- Ada 2005 (AI-231): Remove restriction
10220 and then not Debug_Flag_J
10223 then
10224 -- In the common case of a call which uses an explicitly null value
10225 -- for an access parameter, give specialized error message.
10228 Error_Msg_N
10231 -- Standard message for all other cases (are there any?)
10233 else
10234 Error_Msg_N
10239 -- Ada 2005 (AI-231): Generate the null-excluding check in case of
10240 -- assignment to a null-excluding object.
10245 then
10248 -- Decide whether to generate an if_statement around our
10249 -- null-excluding check to avoid them on certain internal object
10250 -- declarations by looking at the type the current Init_Proc
10251 -- belongs to.
10253 -- Generate:
10254 -- if T1b_skip_null_excluding_check then
10255 -- [constraint_error "access check failed"]
10256 -- end if;
10258 if Needs_Conditional_Null_Excluding_Check
10260 then
10263 Condition =>
10265 New_External_Name
10267 Then_Statements =>
10268 New_List (
10272 -- Otherwise, simply create the check
10274 else
10279 else
10280 Insert_Action
10288 -- In a distributed context, null for a remote access to subprogram may
10289 -- need to be replaced with a special record aggregate. In this case,
10290 -- return after having done the transformation.
10295 then
10299 -- The null literal takes its type from the context
10304 -----------------------
10305 -- Resolve_Op_Concat --
10306 -----------------------
10310 -- We wish to avoid deep recursion, because concatenations are often
10311 -- deeply nested, as in A&B&...&Z. Therefore, we walk down the left
10312 -- operands nonrecursively until we find something that is not a simple
10313 -- concatenation (A in this case). We resolve that, and then walk back
10314 -- up the tree following Parent pointers, calling Resolve_Op_Concat_Rest
10315 -- to do the rest of the work at each level. The Parent pointers allow
10316 -- us to avoid recursion, and thus avoid running out of memory. See also
10317 -- Sem_Ch4.Analyze_Concatenation, where a similar approach is used.
10322 begin
10323 -- The following code is equivalent to:
10325 -- Resolve_Op_Concat_First (NN, Typ);
10326 -- Resolve_Op_Concat_Arg (N, ...);
10327 -- Resolve_Op_Concat_Rest (N, Typ);
10329 -- where the Resolve_Op_Concat_Arg call recurses back here if the left
10330 -- operand is a concatenation.
10332 -- Walk down left operands
10334 loop
10343 -- Now (given the above example) NN is A&B and Op1 is A
10345 -- First resolve Op1 ...
10349 -- ... then walk NN back up until we reach N (where we started), calling
10350 -- Resolve_Op_Concat_Rest along the way.
10352 loop
10359 ---------------------------
10360 -- Resolve_Op_Concat_Arg --
10361 ---------------------------
10363 procedure Resolve_Op_Concat_Arg
10368 is
10372 begin
10374 if Is_Comp
10378 then
10380 else
10384 -- If both Array & Array and Array & Component are visible, there is a
10385 -- potential ambiguity that must be reported.
10390 then
10394 -- If the operation is user-defined and not overloaded use its
10395 -- profile. The operation may be a renaming, in which case it has
10396 -- been rewritten, and we want the original profile.
10401 then
10403 Etype
10407 -- Otherwise an aggregate may match both the array type and the
10408 -- component type.
10410 else
10415 else
10419 then
10420 declare
10425 begin
10430 -- Special-case the error message when the overloading is
10431 -- caused by a function that yields an array and can be
10432 -- called without parameters.
10437 Error_Msg_NE
10439 Error_Msg_NE
10443 else
10451 or else
10453 then
10454 Error_Msg_N -- CODEFIX
10471 then
10472 -- Determine if the out-of-range violation constitutes a
10473 -- warning or an error according to the expression base type,
10474 -- according to Ada 2022 RM 4.9 (35/2).
10477 Apply_Compile_Time_Constraint_Error
10483 Apply_Compile_Time_Constraint_Error
10492 else
10497 else
10504 -----------------------------
10505 -- Resolve_Op_Concat_First --
10506 -----------------------------
10513 begin
10514 -- The parser folds an enormous sequence of concatenations of string
10515 -- literals into "" & "...", where the Is_Folded_In_Parser flag is set
10516 -- in the right operand. If the expression resolves to a predefined "&"
10517 -- operator, all is well. Otherwise, the parser's folding is wrong, so
10518 -- we give an error. See P_Simple_Expression in Par.Ch4.
10523 then
10538 ----------------------------
10539 -- Resolve_Op_Concat_Rest --
10540 ----------------------------
10546 begin
10555 -- If this is not a static concatenation, but the result is a string
10556 -- type (and not an array of strings) ensure that static string operands
10557 -- have their subtypes properly constructed.
10561 then
10567 ----------------------
10568 -- Resolve_Op_Expon --
10569 ----------------------
10574 begin
10575 -- Catch attempts to do fixed-point exponentiation with universal
10576 -- operands, which is a case where the illegality is not caught during
10577 -- normal operator analysis. This is not done in preanalysis mode
10578 -- since the tree is not fully decorated during preanalysis.
10590 then
10599 then
10609 -- We do the resolution using the base type, because intermediate values
10610 -- in expressions are always of the base type, not a subtype of it.
10615 -- For integer types, right argument must be in Natural range
10630 -- Evaluate the exponentiation operator for dimensioned type
10633 else
10637 -- Set overflow checking bit. Much cleverer code needed here eventually
10638 -- and perhaps the Resolve routines should be separated for the various
10639 -- arithmetic operations, since they will need different processing. ???
10648 --------------------
10649 -- Resolve_Op_Not --
10650 --------------------
10654 -- This function determines if the parent node is a boolean operator or
10655 -- operation (comparison op, membership test, or short circuit form) and
10656 -- the not in question is the left operand of this operation. Note that
10657 -- if the not is in parens, then false is returned.
10659 -----------------------
10660 -- Parent_Is_Boolean --
10661 -----------------------
10664 begin
10667 | N_Op_Boolean
10668 | N_Short_Circuit
10672 -- Local variables
10676 -- Start of processing for Resolve_Op_Not
10678 begin
10679 -- Predefined operations on scalar types yield the base type. On the
10680 -- other hand, logical operations on arrays yield the type of the
10681 -- arguments (and the context).
10685 else
10689 -- Straightforward case of incorrect arguments
10696 -- Special case of probable missing parens
10700 Error_Msg_N
10703 else
10704 Error_Msg_N
10711 -- OK resolution of NOT
10713 else
10714 -- Warn if non-boolean types involved. This is a case like not a < b
10715 -- where a and b are modular, where we will get (not a) < b and most
10716 -- likely not (a < b) was intended.
10718 if Warn_On_Questionable_Missing_Parens
10720 and then Parent_Is_Boolean
10721 then
10725 -- Warn on double negation if checking redundant constructs
10727 if Warn_On_Redundant_Constructs
10732 then
10736 -- Complete resolution and evaluation of NOT
10746 -----------------------------
10747 -- Resolve_Operator_Symbol --
10748 -----------------------------
10750 -- Nothing to be done, all resolved already
10756 begin
10760 ----------------------------------
10761 -- Resolve_Qualified_Expression --
10762 ----------------------------------
10770 begin
10774 -- A qualified expression requires an exact match of the type, class-
10775 -- wide matching is not allowed. However, if the qualifying type is
10776 -- specific and the expression has a class-wide type, it may still be
10777 -- okay, since it can be the result of the expansion of a call to a
10778 -- dispatching function, so we also have to check class-wideness of the
10779 -- type of the expression's original node.
10782 or else
10786 then
10790 -- If the target type is unconstrained, then we reset the type of the
10791 -- result from the type of the expression. For other cases, the actual
10792 -- subtype of the expression is the target type. But we avoid doing it
10793 -- for an allocator since this is not needed and might be problematic.
10798 then
10805 -- If we still have a qualified expression after the static evaluation,
10806 -- then apply a scalar range check if needed. The reason that we do this
10807 -- after the Eval call is that otherwise, the application of the range
10808 -- check may convert an illegal static expression and result in warning
10809 -- rather than giving an error (e.g Integer'(Integer'Last + 1)).
10813 then
10817 -- AI12-0100: Once the qualified expression is resolved, check whether
10818 -- operand satisfies a static predicate of the target subtype, if any.
10819 -- In the static expression case, a predicate check failure is an error.
10822 Check_Expression_Against_Static_Predicate
10827 ------------------------------
10828 -- Resolve_Raise_Expression --
10829 ------------------------------
10832 begin
10837 else
10840 -- Apply check for required parentheses in the enclosing
10841 -- context of raise_expressions (RM 11.3 (2)), including default
10842 -- expressions in contexts that can include aspect specifications,
10843 -- and ancestor parts of extension aggregates.
10845 declare
10849 begin
10852 loop
10859 then
10866 if not Parentheses_Found
10868 and then
10870 | N_Floating_Point_Definition
10871 | N_Ordinary_Fixed_Point_Definition
10872 | N_Decimal_Fixed_Point_Definition
10873 | N_Extension_Aggregate
10874 | N_Discriminant_Specification
10875 | N_Parameter_Specification
10876 | N_Formal_Object_Declaration
10879 and then
10881 then
10882 Error_Msg_N
10884 N);
10890 -------------------
10891 -- Resolve_Range --
10892 -------------------
10899 -- Returns True if N is of the form X'First .. X'Last where X is the
10900 -- same entity for both attributes.
10902 --------------------
10903 -- First_Last_Ref --
10904 --------------------
10910 begin
10915 then
10916 declare
10919 begin
10929 -- Start of processing for Resolve_Range
10931 begin
10937 -- Reanalyze the lower bound after both bounds have been analyzed, so
10938 -- that the range is known to be static or not by now. This may trigger
10939 -- more compile-time evaluation, which is useful for static analysis
10940 -- with GNATprove. This is not needed for compilation or static analysis
10941 -- with CodePeer, as full expansion does that evaluation then.
10948 -- Check for inappropriate range on unordered enumeration type
10952 -- Exclude X'First .. X'Last if X is the same entity for both
10954 and then not First_Last_Ref
10955 then
10957 Error_Msg_NE
10964 -- We have to check the bounds for being within the base range as
10965 -- required for a non-static context. Normally this is automatic and
10966 -- done as part of evaluating expressions, but the N_Range node is an
10967 -- exception, since in GNAT we consider this node to be a subexpression,
10968 -- even though in Ada it is not. The circuit in Sem_Eval could check for
10969 -- this, but that would put the test on the main evaluation path for
10970 -- expressions.
10975 -- Check for an ambiguous range over character literals. This will
10976 -- happen with a membership test involving only literals.
10984 -- If bounds are static, constant-fold them, so size computations are
10985 -- identical between front-end and back-end. Do not perform this
10986 -- transformation while analyzing generic units, as type information
10987 -- would be lost when reanalyzing the constant node in the instance.
10999 -- If we have a compile-time-known null range, we warn, because that is
11000 -- likely to be a mistake. (Dynamic null ranges make sense, but often
11001 -- compile-time-known ones do not.) Warn only if this is in a subtype
11002 -- declaration. We do this here, rather than while analyzing a subtype
11003 -- declaration, in case we decide to expand the cases. We do not want to
11004 -- warn in all cases, because some are idiomatic, such as an empty
11005 -- aggregate (1 .. 0 => <>).
11007 -- We don't warn in generics or their instances, because there might be
11008 -- some instances where the range is null, and some where it is not,
11009 -- which would lead to false alarms.
11013 and then Compile_Time_Compare
11019 then
11024 --------------------------
11025 -- Resolve_Real_Literal --
11026 --------------------------
11031 begin
11032 -- Special processing for fixed-point literals to make sure that the
11033 -- value is an exact multiple of the small where this is required. We
11034 -- skip this for the universal real case, and also for generic types.
11040 then
11041 -- We must freeze the base type to get the proper value of the small
11047 declare
11054 begin
11055 -- Case of literal is not an exact multiple of the Small
11059 -- For a source program literal for a decimal fixed-point type,
11060 -- this is statically illegal (RM 4.9(36)).
11065 then
11069 -- Generate a warning if literal from source
11072 and then Warn_On_Bad_Fixed_Value
11073 then
11074 Error_Msg_N
11076 N);
11079 -- Replace literal by a value that is the exact representation
11080 -- of a value of the type, i.e. a multiple of the small value,
11081 -- by truncation, since Machine_Rounds is false for all GNAT
11082 -- fixed-point types (RM 4.9(38)).
11092 -- In all cases, set the corresponding integer field
11098 -- Now replace the actual type by the expected type as usual
11104 -----------------------
11105 -- Resolve_Reference --
11106 -----------------------
11111 begin
11112 -- Replace general access with specific type
11120 -- If we are taking the reference of a volatile entity, then treat it as
11121 -- a potential modification of this entity. This is too conservative,
11122 -- but necessary because remove side effects can cause transformations
11123 -- of normal assignments into reference sequences that otherwise fail to
11124 -- notice the modification.
11131 --------------------------------
11132 -- Resolve_Selected_Component --
11133 --------------------------------
11148 -- Check whether this is the initialization of a component within an
11149 -- init proc (by assignment or call to another init proc). If true,
11150 -- there is no need for a discriminant check.
11152 --------------------
11153 -- Init_Component --
11154 --------------------
11157 begin
11158 return Inside_Init_Proc
11164 -- Start of processing for Resolve_Selected_Component
11166 begin
11169 -- Use the context type to select the prefix that has a selector
11170 -- of the correct name and type.
11178 else
11182 -- Locate selected component. For a private prefix the selector
11183 -- can denote a discriminant.
11187 -- The visible components of a class-wide type are those of
11188 -- the root type.
11198 then
11205 else
11209 Error_Msg_N
11214 else
11217 -- There may be an implicit dereference. Retrieve
11218 -- designated record type.
11222 else
11228 -- Resolution chooses the new interpretation.
11229 -- Find the component with the right name.
11234 loop
11251 -- There must be a legal interpretation at this point
11256 -- In general the expected type is the type of the context, not the
11257 -- type of the candidate selected component.
11262 -- The type of the context and that of the component are
11263 -- compatible and in general identical, but if they are anonymous
11264 -- access-to-subprogram types, the relevant type is that of the
11265 -- component. This matters in Unnest_Subprograms mode, where the
11266 -- relevant context is the one in which the type is declared, not
11267 -- the point of use. This determines what activation record to use.
11272 -- When the type of the component is an access to a class-wide type
11273 -- the relevant type is that of the component (since in such case we
11274 -- may need to generate implicit type conversions or dispatching
11275 -- calls).
11280 then
11284 else
11285 -- Resolve prefix with its type
11290 -- Generate cross-reference. We needed to wait until full overloading
11291 -- resolution was complete to do this, since otherwise we can't tell if
11292 -- we are an lvalue or not.
11296 else
11300 -- If the prefix's type is an access type, get to the real record type.
11301 -- Note: we do not apply an access check because an explicit dereference
11302 -- will be introduced later, and the check will happen there.
11308 else
11312 -- Set flag for expander if discriminant check required on a component
11313 -- appearing within a variant.
11319 and then
11322 and then not Init_Component
11323 then
11331 -- If the prefix is a record conversion, this may be a renamed
11332 -- discriminant whose bounds differ from those of the original
11333 -- one, so we must ensure that a range check is performed.
11338 then
11342 -- Eval_Selected_Component may e.g. fold statically known discriminants.
11348 -- If the record type is atomic and the component is not, then this
11349 -- is worth a warning before Ada 2022, since we have a situation
11350 -- where the access to the component may cause extra read/writes of
11351 -- the atomic object, or partial word accesses, both of which may be
11352 -- unexpected.
11358 then
11359 Error_Msg_N
11362 Error_Msg_N
11372 -------------------
11373 -- Resolve_Shift --
11374 -------------------
11381 begin
11382 -- We do the resolution using the base type, because intermediate values
11383 -- in expressions always are of the base type, not a subtype of it.
11396 ---------------------------
11397 -- Resolve_Short_Circuit --
11398 ---------------------------
11405 begin
11406 -- Ensure all actions associated with the left operand (e.g.
11407 -- finalization of transient objects) are fully evaluated locally within
11408 -- an expression with actions. This is particularly helpful for coverage
11409 -- analysis. However this should not happen in generics or if option
11410 -- Minimize_Expression_With_Actions is set.
11413 declare
11415 begin
11423 -- Set Comes_From_Source on L to preserve warnings for unset
11424 -- reference.
11433 -- Check for issuing warning for always False assert/check, this happens
11434 -- when assertions are turned off, in which case the pragma Assert/Check
11435 -- was transformed into:
11437 -- if False and then <condition> then ...
11439 -- and we detect this pattern
11441 if Warn_On_Assertion_Failure
11448 then
11449 declare
11452 begin
11453 -- Special handling of Asssert pragma
11457 then
11458 declare
11460 Original_Node
11461 (Expression
11464 begin
11465 -- Don't warn if original condition is explicit False,
11466 -- since obviously the failure is expected in this case.
11470 then
11473 -- Issue warning. We do not want the deletion of the
11474 -- IF/AND-THEN to take this message with it. We achieve this
11475 -- by making sure that the expanded code points to the Sloc
11476 -- of the expression, not the original pragma.
11478 else
11479 -- Note: Use Error_Msg_F here rather than Error_Msg_N.
11480 -- The source location of the expression is not usually
11481 -- the best choice here. For example, it gets located on
11482 -- the last AND keyword in a chain of boolean expressiond
11483 -- AND'ed together. It is best to put the message on the
11484 -- first character of the assertion, which is the effect
11485 -- of the First_Node call here.
11487 Error_Msg_F
11489 Expression
11494 -- Similar processing for Check pragma
11498 then
11499 -- Don't want to warn if original condition is explicit False
11501 declare
11503 Original_Node
11504 (Expression
11506 begin
11509 then
11512 -- Post warning
11514 else
11515 -- Again use Error_Msg_F rather than Error_Msg_N, see
11516 -- comment above for an explanation of why we do this.
11518 Error_Msg_F
11520 Expression
11528 -- Continue with processing of short circuit
11537 -------------------
11538 -- Resolve_Slice --
11539 -------------------
11548 begin
11551 -- Use the context type to select the prefix that yields the correct
11552 -- array type.
11554 declare
11560 begin
11568 then
11576 else
11581 else
11592 else
11598 -- If the prefix's type is an access type, get to the real array type.
11599 -- Note: we do not apply an access check because an explicit dereference
11600 -- will be introduced later, and the check will happen there.
11605 -- If the prefix is an access to an unconstrained array, we must use
11606 -- the actual subtype of the object to perform the index checks. The
11607 -- object denoted by the prefix is implicit in the node, so we build
11608 -- an explicit representation for it in order to compute the actual
11609 -- subtype.
11614 declare
11618 begin
11625 -- In CodePeer mode the attribute Image is not expanded, so when it
11626 -- acts as a prefix of a slice, we handle it like a call to function
11627 -- returning an unconstrained string. Same for the Wide variants of
11628 -- attribute Image.
11637 | Name_Wide_Image
11638 | Name_Wide_Wide_Image)
11639 then
11642 -- If the name is a selected component that depends on discriminants,
11643 -- build an actual subtype for it. This can happen only when the name
11644 -- itself is overloaded; otherwise the actual subtype is created when
11645 -- the selected component is analyzed.
11648 and then Full_Analysis
11650 then
11651 declare
11654 begin
11659 -- Maybe this should just be "else", instead of checking for the
11660 -- specific case of slice??? This is needed for the case where the
11661 -- prefix is an Image attribute, which gets expanded to a slice, and so
11662 -- has a constrained subtype which we want to use for the slice range
11663 -- check applied below (the range check won't get done if the
11664 -- unconstrained subtype of the 'Image is used).
11670 -- Obtain the type of the array index
11674 else
11678 -- If name was overloaded, set slice type correctly now
11682 -- Handle the generation of a range check that compares the array index
11683 -- against the discrete_range. The check is not applied to internally
11684 -- built nodes associated with the expansion of dispatch tables. Check
11685 -- that Ada.Tags has already been loaded to avoid extra dependencies on
11686 -- the unit.
11688 if Tagged_Type_Expansion
11694 then
11697 -- The discrete_range is specified by a subtype name. Create an
11698 -- equivalent range attribute, apply checks to this attribute, but
11699 -- insert them into the range expression of the slice itself.
11702 Dexpr :=
11703 Make_Attribute_Reference
11705 Prefix =>
11714 -- The discrete_range is a regular range (or a range attribute, which
11715 -- will be resolved into a regular range). Resolve the bounds and remove
11716 -- their side effects.
11718 else
11735 -- Check bad use of type with predicates
11737 declare
11740 begin
11743 then
11745 else
11750 Bad_Predicated_Subtype_Use
11755 -- Otherwise here is where we check suspicious indexes
11767 ----------------------------
11768 -- Resolve_String_Literal --
11769 ----------------------------
11780 begin
11781 -- For a string appearing in a concatenation, defer creation of the
11782 -- string_literal_subtype until the end of the resolution of the
11783 -- concatenation, because the literal may be constant-folded away. This
11784 -- is a useful optimization for long concatenation expressions.
11786 -- If the string is an aggregate built for a single character (which
11787 -- happens in a non-static context) or a is null string to which special
11788 -- checks may apply, we build the subtype. Wide strings must also get a
11789 -- string subtype if they come from a one character aggregate. Strings
11790 -- generated by attributes might be static, but it is often hard to
11791 -- determine whether the enclosing context is static, so we generate
11792 -- subtypes for them as well, thus losing some rarer optimizations ???
11793 -- Same for strings that come from a static conversion.
11795 Need_Check :=
11804 -- If the resolving type is itself a string literal subtype, we can just
11805 -- reuse it, since there is no point in creating another.
11811 and then not Need_Check
11813 | N_Attribute_Reference
11814 | N_Qualified_Expression
11815 | N_Type_Conversion
11816 then
11819 -- Do not generate a string literal subtype for the default expression
11820 -- of a formal parameter in GNATprove mode. This is because the string
11821 -- subtype is associated with the freezing actions of the subprogram,
11822 -- however freezing is disabled in GNATprove mode and as a result the
11823 -- subtype is unavailable.
11825 elsif GNATprove_Mode
11827 then
11830 -- Otherwise we must create a string literal subtype. Note that the
11831 -- whole idea of string literal subtypes is simply to avoid the need
11832 -- for building a full fledged array subtype for each literal.
11834 else
11840 or else Need_Check
11841 then
11848 then
11854 -- The validity of a null string has been checked in the call to
11855 -- Eval_String_Literal.
11860 -- Always accept string literal with component type Any_Character, which
11861 -- occurs in error situations and in comparisons of literals, both of
11862 -- which should accept all literals.
11867 -- If the type is bit-packed, then we always transform the string
11868 -- literal into a full fledged aggregate.
11873 -- Deal with cases of Wide_Wide_String, Wide_String, and String
11875 else
11876 -- For Standard.Wide_Wide_String, or any other type whose component
11877 -- type is Standard.Wide_Wide_Character, we know that all the
11878 -- characters in the string must be acceptable, since the parser
11879 -- accepted the characters as valid character literals.
11884 -- For the case of Standard.String, or any other type whose component
11885 -- type is Standard.Character, we must make sure that there are no
11886 -- wide characters in the string, i.e. that it is entirely composed
11887 -- of characters in range of type Character.
11889 -- If the string literal is the result of a static concatenation, the
11890 -- test has already been performed on the components, and need not be
11891 -- repeated.
11895 then
11899 -- If we are out of range, post error. This is one of the
11900 -- very few places that we place the flag in the middle of
11901 -- a token, right under the offending wide character. Not
11902 -- quite clear if this is right wrt wide character encoding
11903 -- sequences, but it's only an error message.
11905 Error_Msg
11912 -- For the case of Standard.Wide_String, or any other type whose
11913 -- component type is Standard.Wide_Character, we must make sure that
11914 -- there are no wide characters in the string, i.e. that it is
11915 -- entirely composed of characters in range of type Wide_Character.
11917 -- If the string literal is the result of a static concatenation,
11918 -- the test has already been performed on the components, and need
11919 -- not be repeated.
11923 then
11927 -- If we are out of range, post error. This is one of the
11928 -- very few places that we place the flag in the middle of
11929 -- a token, right under the offending wide character.
11931 -- This is not quite right, because characters in general
11932 -- will take more than one character position ???
11934 Error_Msg
11941 -- If the root type is not a standard character, then we will convert
11942 -- the string into an aggregate and will let the aggregate code do
11943 -- the checking. Standard Wide_Wide_Character is also OK here.
11945 else
11949 -- See if the component type of the array corresponding to the string
11950 -- has compile time known bounds. If yes we can directly check
11951 -- whether the evaluation of the string will raise constraint error.
11952 -- Otherwise we need to transform the string literal into the
11953 -- corresponding character aggregate and let the aggregate code do
11954 -- the checking. We use the same transformation if the component
11955 -- type has a static predicate, which will be applied to each
11956 -- character when the aggregate is resolved.
11960 -- Check for the case of full range, where we are definitely OK
11966 -- Here the range is not the complete base type range, so check
11968 declare
11976 begin
11979 then
11985 then
11986 Apply_Compile_Time_Constraint_Error
11988 CE_Range_Check_Failed,
12001 -- If we got here we meed to transform the string literal into the
12002 -- equivalent qualified positional array aggregate. This is rather
12003 -- heavy artillery for this situation, but it is hard work to avoid.
12005 declare
12010 begin
12011 -- Build the character literals, we give them source locations that
12012 -- correspond to the string positions, which is a bit tricky given
12013 -- the possible presence of wide character escape sequences.
12027 -- Should we have a call to Skip_Wide here ???
12029 -- ??? else
12030 -- Skip_Wide (P);
12038 Expression =>
12045 -------------------------
12046 -- Resolve_Target_Name --
12047 -------------------------
12050 begin
12054 -----------------------------
12055 -- Resolve_Type_Conversion --
12056 -----------------------------
12068 -- Set to False to suppress cases where we want to suppress the test
12069 -- for redundancy to avoid possible false positives on this warning.
12071 begin
12072 if not Conv_OK
12074 then
12078 -- If the Operand Etype is Universal_Fixed, then the conversion is
12079 -- never redundant. We need this check because by the time we have
12080 -- finished the rather complex transformation, the conversion looks
12081 -- redundant when it is not.
12086 -- If the operand is marked as Any_Fixed, then special processing is
12087 -- required. This is also a case where we suppress the test for a
12088 -- redundant conversion, since most certainly it is not redundant.
12093 -- Mixed-mode operation involving a literal. Context must be a fixed
12094 -- type which is applied to the literal subsequently.
12096 -- Multiplication and division involving two fixed type operands must
12097 -- yield a universal real because the result is computed in arbitrary
12098 -- precision.
12104 then
12110 or else
12112 then
12113 -- Return if expression is ambiguous
12118 -- If nothing else, the available fixed type is Duration
12120 else
12124 -- Resolve the real operand with largest available precision
12128 else
12134 -- If the operand is a literal (it could be a non-static and
12135 -- illegal exponentiation) check whether the use of Duration
12136 -- is potentially inaccurate.
12141 then
12142 Error_Msg_N
12145 Error_Msg_N
12152 then
12155 else
12166 -- Note: we do the Eval_Type_Conversion call before applying the
12167 -- required checks for a subtype conversion. This is important, since
12168 -- both are prepared under certain circumstances to change the type
12169 -- conversion to a constraint error node, but in the case of
12170 -- Eval_Type_Conversion this may reflect an illegality in the static
12171 -- case, and we would miss the illegality (getting only a warning
12172 -- message), if we applied the type conversion checks first.
12176 -- Even when evaluation is not possible, we may be able to simplify the
12177 -- conversion or its expression. This needs to be done before applying
12178 -- checks, since otherwise the checks may use the original expression
12179 -- and defeat the simplifications. This is specifically the case for
12180 -- elimination of the floating-point Truncation attribute in
12181 -- float-to-int conversions.
12185 -- If after evaluation we still have a type conversion, then we may need
12186 -- to apply checks required for a subtype conversion. But skip them if
12187 -- universal fixed operands are involved, since range checks are handled
12188 -- separately for these cases, after the expansion done by Exp_Fixd.
12194 then
12198 -- Issue warning for conversion of simple object to its own type. We
12199 -- have to test the original nodes, since they may have been rewritten
12200 -- by various optimizations.
12204 -- Here we test for a redundant conversion if the warning mode is
12205 -- active (and was not locally reset), and we have a type conversion
12206 -- from source not appearing in a generic instance.
12208 if Test_Redundant
12211 and then not In_Instance
12212 then
12216 -- If the node is part of a larger expression, the Target_Type
12217 -- may not be the original type of the node if the context is a
12218 -- condition. Recover original type to see if conversion is needed.
12222 then
12226 -- If we have an entity name, then give the warning if the entity
12227 -- is the right type, or if it is a loop parameter covered by the
12228 -- original type (that's needed because loop parameters have an
12229 -- odd subtype coming from the bounds).
12233 and then
12235 or else
12239 -- If not an entity, then type of expression must match
12242 then
12243 -- One more check, do not give warning if the analyzed conversion
12244 -- has an expression with non-static bounds, and the bounds of the
12245 -- target are static. This avoids junk warnings in cases where the
12246 -- conversion is necessary to establish staticness, for example in
12247 -- a case statement.
12251 then
12254 -- Never give a warning if the operand is a conditional expression
12255 -- because RM 4.5.7(10/3) forces its type to be the target type.
12260 -- Finally, if this type conversion occurs in a context requiring
12261 -- a prefix, and the expression is a qualified expression then the
12262 -- type conversion is not redundant, since a qualified expression
12263 -- is not a prefix, whereas a type conversion is. For example, "X
12264 -- := T'(Funx(...)).Y;" is illegal because a selected component
12265 -- requires a prefix, but a type conversion makes it legal: "X :=
12266 -- T(T'(Funx(...))).Y;"
12268 -- In Ada 2012, a qualified expression is a name, so this idiom is
12269 -- no longer needed, but we still suppress the warning because it
12270 -- seems unfriendly for warnings to pop up when you switch to the
12271 -- newer language version.
12275 | N_Indexed_Component
12276 | N_Selected_Component
12277 | N_Slice
12278 | N_Explicit_Dereference
12279 then
12282 -- Never warn on conversion to Long_Long_Integer'Base since
12283 -- that is most likely an artifact of the extended overflow
12284 -- checking and comes from complex expanded code.
12289 -- Do not warn on conversion to class-wide type on helpers of
12290 -- class-wide preconditions because in this context the warning
12291 -- would be spurious (since the class-wide precondition has been
12292 -- installed in the return statement of the helper, which has a
12293 -- class-wide formal type instead of a regular tagged type).
12298 then
12301 -- Here we give the redundant conversion warning. If it is an
12302 -- entity, give the name of the entity in the message. If not,
12303 -- just mention the expression.
12305 else
12308 Error_Msg_NE -- CODEFIX
12311 else
12312 Error_Msg_NE
12320 -- Ada 2005 (AI-251): Handle class-wide interface type conversions.
12321 -- No need to perform any interface conversion if the type of the
12322 -- expression coincides with the target type.
12325 and then Expander_Active
12327 then
12328 declare
12332 begin
12333 -- If the type of the operand is a limited view, use nonlimited
12334 -- view when available. If it is a class-wide type, recover the
12335 -- class-wide type of the nonlimited view.
12339 then
12344 -- It seems that Non_Limited_View should also be applied for
12345 -- Target when it has a limited view, but that leads to missing
12346 -- error checks on interface conversions further below. ???
12351 -- If the type of the operand is a limited view, use nonlimited
12352 -- view when available. If it is a class-wide type, recover the
12353 -- class-wide type of the nonlimited view.
12357 then
12365 -- If the target type is a limited view, use nonlimited view
12366 -- when available.
12370 then
12378 -- Conversion from interface type
12380 -- It seems that it would be better for the error checks below
12381 -- to be performed as part of Validate_Conversion (and maybe some
12382 -- of the error checks above could be moved as well?). ???
12386 -- Ada 2005 (AI-217): Handle entities from limited views
12390 Error_Msg_NE -- CODEFIX
12393 Error_Msg_N
12395 N);
12398 and then not
12401 then
12403 Error_Msg_NE -- CODEFIX
12406 Error_Msg_N
12408 N);
12410 else
12414 -- Conversion to interface type
12422 -- Ada 2012: Once the type conversion is resolved, check whether the
12423 -- operand satisfies a static predicate of the target subtype, if any.
12424 -- In the static expression case, a predicate check failure is an error.
12427 Check_Expression_Against_Static_Predicate
12431 -- If at this stage we have a fixed to integer conversion, make sure the
12432 -- Do_Range_Check flag is set, because such conversions in general need
12433 -- a range check. We only need this if expansion is off, see above why.
12436 and then not Expander_Active
12441 then
12445 -- Generating C code a type conversion of an access to constrained
12446 -- array type to access to unconstrained array type involves building
12447 -- a fat pointer which in general cannot be generated on the fly. We
12448 -- remove side effects in order to store the result of the conversion
12449 -- into a temporary.
12451 if Modify_Tree_For_C
12458 then
12463 ----------------------
12464 -- Resolve_Unary_Op --
12465 ----------------------
12474 begin
12475 -- Deal with intrinsic unary operators
12481 then
12486 -- Deal with universal cases
12495 -- Generate warning for negative literal of a modular type, unless it is
12496 -- enclosed directly in a type qualification or a type conversion, as it
12497 -- is likely not what the user intended. We don't issue the warning for
12498 -- the common use of -1 to denote OxFFFF_FFFF...
12500 if Warn_On_Suspicious_Modulus_Value
12506 | N_Type_Conversion
12508 then
12509 Error_Msg_N
12514 Error_Msg_N
12518 -- Generate warning for expressions like abs (x mod 2)
12520 if Warn_On_Redundant_Constructs
12522 then
12526 Error_Msg_N -- CODEFIX
12531 -- Deal with reference generation
12538 -- Set overflow checking bit. Much cleverer code needed here eventually
12539 -- and perhaps the Resolve routines should be separated for the various
12540 -- arithmetic operations, since they will need different processing ???
12548 -- Generate warning for expressions like -5 mod 3 for integers. No need
12549 -- to worry in the floating-point case, since parens do not affect the
12550 -- result so there is no point in giving in a warning.
12552 declare
12561 begin
12562 if Warn_On_Questionable_Missing_Parens
12566 then
12569 -- We are looking for cases where the right operand is not
12570 -- parenthesized, and is a binary operator, multiply, divide, or
12571 -- mod. These are the cases where the grouping can affect results.
12575 then
12576 -- For mod, we always give the warning, since the value is
12577 -- affected by the parenthesization (e.g. (-5) mod 315 /=
12578 -- -(5 mod 315)). But for the other cases, the only concern is
12579 -- overflow, e.g. for the case of 8 big signed (-(2 * 64)
12580 -- overflows, but (-2) * 64 does not). So we try to give the
12581 -- message only when overflow is possible.
12585 then
12590 else
12596 else
12600 -- Note that the test below is deliberately excluding the
12601 -- largest negative number, since that is a potentially
12602 -- troublesome case (e.g. -2 * x, where the result is the
12603 -- largest negative integer has an overflow with 2 * x).
12610 -- For the multiplication case, the only case we have to worry
12611 -- about is when (-a)*b is exactly the largest negative number
12612 -- so that -(a*b) can cause overflow. This can only happen if
12613 -- a is a power of 2, and more generally if any operand is a
12614 -- constant that is not a power of 2, then the parentheses
12615 -- cannot affect whether overflow occurs. We only bother to
12616 -- test the left most operand
12618 -- Loop looking at left operands for one that has known value
12625 -- Operand value of 0 or 1 skips warning
12630 -- Otherwise check power of 2, if power of 2, warn, if
12631 -- anything else, skip warning.
12633 else
12637 else
12646 -- Keep looking at left operands
12651 -- For rem or "/" we can only have a problematic situation
12652 -- if the divisor has a value of minus one or one. Otherwise
12653 -- overflow is impossible (divisor > 1) or we have a case of
12654 -- division by zero in any case.
12659 then
12663 -- If we fall through warning should be issued
12665 -- Shouldn't we test Warn_On_Questionable_Missing_Parens ???
12667 Error_Msg_N
12674 ----------------------------------
12675 -- Resolve_Unchecked_Expression --
12676 ----------------------------------
12678 procedure Resolve_Unchecked_Expression
12681 is
12682 begin
12687 ---------------------------------------
12688 -- Resolve_Unchecked_Type_Conversion --
12689 ---------------------------------------
12691 procedure Resolve_Unchecked_Type_Conversion
12694 is
12700 begin
12701 -- Resolve operand using its own type
12705 -- If the expression is a conversion to universal integer of an
12706 -- an expression with an integer type, then we can eliminate the
12707 -- intermediate conversion to universal integer.
12712 then
12717 -- In an inlined context, the unchecked conversion may be applied
12718 -- to a literal, in which case its type is the type of the context.
12719 -- (In other contexts conversions cannot apply to literals).
12721 if In_Inlined_Body
12725 then
12733 ------------------------------
12734 -- Rewrite_Operator_As_Call --
12735 ------------------------------
12742 begin
12749 New_N :=
12760 ------------------------------
12761 -- Rewrite_Renamed_Operator --
12762 ------------------------------
12764 procedure Rewrite_Renamed_Operator
12768 is
12773 begin
12774 -- Do not perform this transformation within a pre/postcondition,
12775 -- because the expression will be reanalyzed, and the transformation
12776 -- might affect the visibility of the operator, e.g. in an instance.
12777 -- Note that fully analyzed and expanded pre/postconditions appear as
12778 -- pragma Check equivalents.
12784 -- Likewise when an expression function is being preanalyzed, since the
12785 -- expression will be reanalyzed as part of the generated body.
12788 declare
12790 begin
12793 N_Expression_Function
12794 then
12810 -- Indicate that both the original entity and its renaming are
12811 -- referenced at this point.
12818 -- If the context type is private, add the appropriate conversions so
12819 -- that the operator is applied to the full view. This is done in the
12820 -- routines that resolve intrinsic operators.
12824 when N_Op_Add
12825 | N_Op_Divide
12826 | N_Op_Expon
12827 | N_Op_Mod
12828 | N_Op_Multiply
12829 | N_Op_Rem
12830 | N_Op_Subtract
12831 =>
12834 when N_Op_Abs
12835 | N_Op_Minus
12836 | N_Op_Plus
12837 =>
12846 -----------------------
12847 -- Set_Slice_Subtype --
12848 -----------------------
12850 -- Build an implicit subtype declaration to represent the type delivered by
12851 -- the slice. This is an abbreviated version of an array subtype. We define
12852 -- an index subtype for the slice, using either the subtype name or the
12853 -- discrete range of the slice. To be consistent with index usage elsewhere
12854 -- we create a list header to hold the single index. This list is not
12855 -- otherwise attached to the syntax tree.
12866 begin
12872 else
12873 -- We force the evaluation of a range. This is definitely needed in
12874 -- the renamed case, and seems safer to do unconditionally. Note in
12875 -- any case that since we will create and insert an Itype referring
12876 -- to this range, we must make sure any side effect removal actions
12877 -- are inserted before the Itype definition.
12883 -- If the discrete range is given by a subtype indication, the
12884 -- type of the slice is the base of the subtype mark.
12887 declare
12889 begin
12898 -- Take a new copy of Drange (where bounds have been rewritten to
12899 -- reference side-effect-free names). Using a separate tree ensures
12900 -- that further expansion (e.g. while rewriting a slice assignment
12901 -- into a FOR loop) does not attempt to remove side effects on the
12902 -- bounds again (which would cause the bounds in the index subtype
12903 -- definition to refer to temporaries before they are defined) (the
12904 -- reason is that some names are considered side effect free here
12905 -- for the subtype, but not in the context of a loop iteration
12906 -- scheme).
12928 -- The Etype of the existing Slice node is reset to this slice subtype.
12929 -- Its bounds are obtained from its first index.
12933 -- For bit-packed slice subtypes, freeze immediately (except in the case
12934 -- of being in a "spec expression" where we never freeze when we first
12935 -- see the expression).
12940 -- For all other cases insert an itype reference in the slice's actions
12941 -- so that the itype is frozen at the proper place in the tree (i.e. at
12942 -- the point where actions for the slice are analyzed). Note that this
12943 -- is different from freezing the itype immediately, which might be
12944 -- premature (e.g. if the slice is within a transient scope). This needs
12945 -- to be done only if expansion is enabled.
12952 --------------------------------
12953 -- Set_String_Literal_Subtype --
12954 --------------------------------
12962 begin
12974 -- The low bound is set from the low bound of the corresponding index
12975 -- type. Note that we do not store the high bound in the string literal
12976 -- subtype, but it can be deduced if necessary from the length and the
12977 -- low bound.
12982 -- If the lower bound is not static we create a range for the string
12983 -- literal, using the index type and the known length of the literal.
12984 -- If the length is 1, then the upper bound is set to a mere copy of
12985 -- the lower bound; or else, if the index type is a signed integer,
12986 -- then the upper bound is computed as Low_Bound + L - 1; otherwise,
12987 -- the upper bound is computed as T'Val (T'Pos (Low_Bound) + L - 1).
12989 else
12990 declare
13000 begin
13005 High_Bound :=
13010 else
13011 High_Bound :=
13014 Prefix =>
13018 Left_Opnd =>
13021 Prefix =>
13023 Expressions =>
13025 Right_Opnd =>
13030 Set_String_Literal_Low_Bound
13033 else
13034 -- If the index type is an enumeration type, build bounds
13035 -- expression with attributes.
13037 Set_String_Literal_Low_Bound
13041 Prefix =>
13045 Analyze_And_Resolve
13048 -- Build bona fide subtype for the string, and wrap it in an
13049 -- unchecked conversion, because the back end expects the
13050 -- String_Literal_Subtype to have a static lower bound.
13052 Index_Subtype :=
13059 -- In this context, the Index_Type may already have a constraint,
13060 -- so use common base type on string subtype. The base type may
13061 -- be used when generating attributes of the string, for example
13062 -- in the context of a slice assignment.
13084 ------------------------------
13085 -- Simplify_Type_Conversion --
13086 ------------------------------
13089 begin
13091 declare
13096 begin
13097 -- Special processing if the conversion is the expression of a
13098 -- Rounding or Truncation attribute reference. In this case we
13099 -- replace:
13101 -- ityp (ftyp'Rounding (x)) or ityp (ftyp'Truncation (x))
13103 -- by
13105 -- ityp (x)
13107 -- with the Float_Truncate flag set to False or True respectively,
13108 -- which is more efficient. We reuse Rounding for Machine_Rounding
13109 -- as System.Fat_Gen, which is a permissible behavior.
13112 and then
13118 | Name_Machine_Rounding
13119 | Name_Truncation
13120 then
13121 declare
13124 begin
13130 -- Special processing for the conversion of an integer literal to
13131 -- a dynamic type: we first convert the literal to the root type
13132 -- and then convert the result to the target type, the goal being
13133 -- to avoid doing range checks in universal integer.
13139 then
13143 -- If the expression is a conversion to universal integer of an
13144 -- an expression with an integer type, then we can eliminate the
13145 -- intermediate conversion to universal integer.
13150 then
13158 ------------------------------
13159 -- Try_User_Defined_Literal --
13160 ------------------------------
13162 function Try_User_Defined_Literal
13165 is
13166 begin
13171 -- Both dependent expressions must have the same type as the context
13173 declare
13178 begin
13192 -- All dependent expressions must have the same type as the context
13194 declare
13197 begin
13202 then
13203 declare
13206 begin
13230 -------------------------------------------
13231 -- Try_User_Defined_Literal_For_Operator --
13232 -------------------------------------------
13234 function Try_User_Defined_Literal_For_Operator
13237 is
13238 begin
13240 | N_Op_Divide
13241 | N_Op_Mod
13242 | N_Op_Multiply
13243 | N_Op_Rem
13244 | N_Op_Subtract
13245 then
13246 -- Both operands must have the same type as the context
13247 -- (ignoring for now fixed-point and exponentiation ops).
13252 then
13260 then
13267 -- For other binary operators the context does not impose a type on
13268 -- the operands, but their types must match.
13271 not in N_Integer_Literal | N_String_Literal | N_Real_Literal
13272 and then
13273 Has_Applicable_User_Defined_Literal
13275 then
13280 not in N_Integer_Literal | N_String_Literal | N_Real_Literal
13281 and then
13282 Has_Applicable_User_Defined_Literal
13284 then
13291 then
13299 -----------------------------
13300 -- Unique_Fixed_Point_Type --
13301 -----------------------------
13305 -- Give error messages for true ambiguity. Messages are posted on node
13306 -- N, and entities T1, T2 are the possible interpretations.
13308 -----------------------
13309 -- Fixed_Point_Error --
13310 -----------------------
13313 begin
13319 -- Local variables
13327 -- Start of processing for Unique_Fixed_Point_Type
13329 begin
13330 -- The operations on Duration are visible, so Duration is always a
13331 -- possible interpretation.
13335 -- Look for fixed-point types in enclosing scopes
13344 then
13348 else
13359 -- Look for visible fixed type declarations in the context
13370 then
13374 else
13389 else
13390 -- When the context is a type conversion, issue the warning on the
13391 -- expression of the conversion because it is the actual operation.
13395 else
13399 Error_Msg_NE
13406 ----------------------
13407 -- Valid_Conversion --
13408 ----------------------
13410 function Valid_Conversion
13415 is
13420 function Conversion_Check
13423 -- Little routine to post Msg if Valid is False, returns Valid value
13426 -- If Report_Errs, then calls Errout.Error_Msg_N with its arguments
13428 procedure Conversion_Error_NE
13432 -- If Report_Errs, then calls Errout.Error_Msg_NE with its arguments
13435 -- Return True if expression is within an instance but is not in one of
13436 -- the actuals of the instantiation. Type conversions within an instance
13437 -- are not rechecked because type visibility may lead to spurious errors
13438 -- but conversions in an actual for a formal object must be checked.
13440 function Is_Discrim_Of_Bad_Access_Conversion_Argument
13442 -- Implicit anonymous-to-named access type conversions are not allowed
13443 -- if the "statically deeper than" relationship does not apply to the
13444 -- type of the conversion operand. See RM 8.6(28.1) and AARM 8.6(28.d).
13445 -- We deal with most such cases elsewhere so that we can emit more
13446 -- specific error messages (e.g., if the operand is an access parameter
13447 -- or a saooaaat (stand-alone object of an anonymous access type)), but
13448 -- here is where we catch the case where the operand is an access
13449 -- discriminant selected from a dereference of another such "bad"
13450 -- conversion argument.
13452 function Valid_Tagged_Conversion
13455 -- Specifically test for validity of tagged conversions
13458 -- Check index and component conformance, and accessibility levels if
13459 -- the component types are anonymous access types (Ada 2005).
13461 ----------------------
13462 -- Conversion_Check --
13463 ----------------------
13465 function Conversion_Check
13468 is
13469 begin
13470 if not Valid
13472 -- A generic unit has already been analyzed and we have verified
13473 -- that a particular conversion is OK in that context. Since the
13474 -- instance is reanalyzed without relying on the relationships
13475 -- established during the analysis of the generic, it is possible
13476 -- to end up with inconsistent views of private types. Do not emit
13477 -- the error message in such cases. The rest of the machinery in
13478 -- Valid_Conversion still ensures the proper compatibility of
13479 -- target and operand types.
13481 and then not In_Instance_Code
13482 then
13489 ------------------------
13490 -- Conversion_Error_N --
13491 ------------------------
13494 begin
13500 -------------------------
13501 -- Conversion_Error_NE --
13502 -------------------------
13504 procedure Conversion_Error_NE
13508 is
13509 begin
13515 ----------------------
13516 -- In_Instance_Code --
13517 ----------------------
13522 begin
13526 else
13530 -- The expression is part of an actual object if it appears in
13531 -- the generated object declaration in the instance.
13535 then
13538 else
13539 exit when
13548 -- Otherwise the expression appears within the instantiated unit
13554 --------------------------------------------------
13555 -- Is_Discrim_Of_Bad_Access_Conversion_Argument --
13556 --------------------------------------------------
13558 function Is_Discrim_Of_Bad_Access_Conversion_Argument
13560 is
13566 begin
13578 -- return False if Expr not of form <prefix>.all.Some_Component
13582 then
13583 -- conditional expressions, declare expressions ???
13590 -- The "statically deeper relationship" does not apply
13591 -- to generic formal access types, so a prefix of such
13592 -- a type is a "bad" prefix.
13597 -- The "statically deeper relationship" does apply to
13598 -- any other named access type.
13607 -- The "statically deeper relationship" applies to some
13608 -- anonymous access types and not to others. Return
13609 -- True for the cases where it does not apply. Also check
13610 -- recursively for the
13611 -- <prefix>.all.Access_Discrim.all.Access_Discrim case,
13612 -- where the correct result depends on <prefix>.
13615 N_Procedure_Specification | -- access parameter
13616 N_Function_Specification | -- access parameter
13617 N_Object_Declaration -- saooaaat
13621 ----------------------------
13622 -- Valid_Array_Conversion --
13623 ----------------------------
13640 begin
13641 -- Error if wrong number of dimensions
13643 if
13645 then
13646 Conversion_Error_N
13650 -- Number of dimensions matches
13652 else
13653 -- Loop through indexes of the two arrays
13661 -- Error if index types are incompatible
13667 then
13668 Conversion_Error_N
13670 Operand);
13678 -- If component types have same base type, all set
13683 -- Here if base types of components are not the same. The only
13684 -- time this is allowed is if we have anonymous access types.
13686 -- The conversion of arrays of anonymous access types can lead
13687 -- to dangling pointers. AI-392 formalizes the accessibility
13688 -- checks that must be applied to such conversions to prevent
13689 -- out-of-scope references.
13692 E_Anonymous_Access_Type
13693 | E_Anonymous_Access_Subprogram_Type
13695 and then
13697 then
13700 then
13703 Conversion_Error_N
13713 -- Conversion not allowed because of accessibility levels
13715 else
13716 Conversion_Error_N
13722 else
13726 -- All other cases where component base types do not match
13728 else
13729 Conversion_Error_N
13731 Operand);
13735 -- Check that component subtypes statically match. For numeric
13736 -- types this means that both must be either constrained or
13737 -- unconstrained. For enumeration types the bounds must match.
13738 -- All of this is checked in Subtypes_Statically_Match.
13740 if not Subtypes_Statically_Match
13742 then
13743 Conversion_Error_N
13752 -----------------------------
13753 -- Valid_Tagged_Conversion --
13754 -----------------------------
13756 function Valid_Tagged_Conversion
13759 is
13760 begin
13761 -- Upward conversions are allowed (RM 4.6(22))
13765 then
13768 -- Downward conversion are allowed if the operand is class-wide
13769 -- (RM 4.6(23)).
13773 then
13778 then
13779 return
13783 -- Ada 2005 (AI-251): A conversion is valid if the operand and target
13784 -- types are both class-wide types and the specific type associated
13785 -- with at least one of them is an interface type (RM 4.6 (23.1/2));
13786 -- at run-time a check will verify the validity of this interface
13787 -- type conversion.
13793 then
13796 -- Report errors
13801 and then not Interface_Present_In_Ancestor
13804 then
13807 Conversion_Error_N
13815 and then not Interface_Present_In_Ancestor
13818 then
13821 Conversion_Error_N
13825 -- Search for interface types shared between the target type and
13826 -- the operand interface type to complete the text of the error
13827 -- since the source of this error is a missing type conversion
13828 -- to such interface type.
13831 declare
13838 begin
13840 Target_Ifaces_List);
13842 Operand_Ifaces_List);
13850 then
13851 Error_Msg_Name_1 :=
13856 Conversion_Error_N
13859 else
13860 Conversion_Error_N
13878 then
13879 Conversion_Error_N
13881 Conversion_Error_N
13887 then
13888 Conversion_Error_N
13893 else
13894 Conversion_Error_NE
13901 -- Start of processing for Valid_Conversion
13903 begin
13907 declare
13915 begin
13916 -- Remove procedure calls, which syntactically cannot appear in
13917 -- this context, but which cannot be removed by type checking,
13918 -- because the context does not impose a type.
13920 -- The node may be labelled overloaded, but still contain only one
13921 -- interpretation because others were discarded earlier. If this
13922 -- is the case, retain the single interpretation if legal.
13930 then
13931 -- More than one candidate interpretation is available
13939 -- When compiling for a system where Address is of a visible
13940 -- integer type, spurious ambiguities can be produced when
13941 -- arithmetic operations have a literal operand and return
13942 -- System.Address or a descendant of it. These ambiguities
13943 -- are usually resolved by the context, but for conversions
13944 -- there is no context type and the removal of the spurious
13945 -- operations must be done explicitly here.
13947 if not Address_Is_Private
13949 then
13974 Conversion_Error_N
13977 -- If the interpretation involves a standard operator, use
13978 -- the location of the type, which may be user-defined.
13982 else
13986 Conversion_Error_N -- CODEFIX
13991 else
13995 Conversion_Error_N -- CODEFIX
14007 -- Deal with conversion of integer type to address if the pragma
14008 -- Allow_Integer_Address is in effect. We convert the conversion to
14009 -- an unchecked conversion in this case and we are all done.
14017 -- If we are within a child unit, check whether the type of the
14018 -- expression has an ancestor in a parent unit, in which case it
14019 -- belongs to its derivation class even if the ancestor is private.
14020 -- See RM 7.3.1 (5.2/3).
14024 -- Numeric types
14028 -- A universal fixed expression can be converted to any numeric type
14033 -- Also no need to check when in an instance or inlined body, because
14034 -- the legality has been established when the template was analyzed.
14035 -- Furthermore, numeric conversions may occur where only a private
14036 -- view of the operand type is visible at the instantiation point.
14037 -- This results in a spurious error if we check that the operand type
14038 -- is a numeric type.
14040 -- Note: in a previous version of this unit, the following tests were
14041 -- applied only for generated code (Comes_From_Source set to False),
14042 -- but in fact the test is required for source code as well, since
14043 -- this situation can arise in source code.
14048 -- Otherwise we need the conversion check
14050 else
14051 return Conversion_Check
14053 or else
14059 -- Array types
14065 then
14066 Conversion_Error_N
14070 else
14074 -- Ada 2005 (AI-251): Internally generated conversions of access to
14075 -- interface types added to force the displacement of the pointer to
14076 -- reference the corresponding dispatch table.
14081 then
14084 -- Ada 2005 (AI-251): Anonymous access types where target references an
14085 -- interface type.
14089 E_General_Access_Type | E_Anonymous_Access_Type
14091 then
14092 -- Check the static accessibility rule of 4.6(17). Note that the
14093 -- check is not enforced when within an instance body, since the
14094 -- RM requires such cases to be caught at run time.
14096 -- If the operand is a rewriting of an allocator no check is needed
14097 -- because there are no accessibility issues.
14105 then
14106 -- In an instance, this is a run-time check, but one we know
14107 -- will fail, so generate an appropriate warning. The raise
14108 -- will be generated by Expand_N_Type_Conversion.
14112 Conversion_Error_N
14114 Operand);
14117 else
14118 Conversion_Error_N
14120 Operand);
14124 -- Special accessibility checks are needed in the case of access
14125 -- discriminants declared for a limited type.
14129 then
14130 -- When the operand is a selected access discriminant the check
14131 -- needs to be made against the level of the object denoted by
14132 -- the prefix of the selected name (Accessibility_Level handles
14133 -- checking the prefix of the operand for this case).
14136 and then Static_Accessibility_Level
14139 then
14140 -- In an instance, this is a run-time check, but one we know
14141 -- will fail, so generate an appropriate warning. The raise
14142 -- will be generated by Expand_N_Type_Conversion.
14146 Conversion_Error_N
14151 -- Real error if not in instance body
14153 else
14154 Conversion_Error_N
14161 -- The case of a reference to an access discriminant from
14162 -- within a limited type declaration (which will appear as
14163 -- a discriminal) is always illegal because the level of the
14164 -- discriminant is considered to be deeper than any (nameable)
14165 -- access type.
14169 and then
14172 then
14173 Conversion_Error_N
14175 Operand);
14183 -- General and anonymous access types
14186 E_General_Access_Type | E_Anonymous_Access_Type
14187 and then
14188 Conversion_Check
14190 and then
14192 E_Access_Subprogram_Type |
14193 E_Access_Protected_Subprogram_Type,
14195 then
14198 then
14199 Conversion_Error_N
14204 -- Check the static accessibility rule of 4.6(17). Note that the
14205 -- check is not enforced when within an instance body, since the RM
14206 -- requires such cases to be caught at run time.
14211 N_Object_Declaration
14212 then
14213 -- Ada 2012 (AI05-0149): Perform legality checking on implicit
14214 -- conversions from an anonymous access type to a named general
14215 -- access type. Such conversions are not allowed in the case of
14216 -- access parameters and stand-alone objects of an anonymous
14217 -- access type. The implicit conversion case is recognized by
14218 -- testing that Comes_From_Source is False and that it's been
14219 -- rewritten. The Comes_From_Source test isn't sufficient because
14220 -- nodes in inlined calls to predefined library routines can have
14221 -- Comes_From_Source set to False. (Is there a better way to test
14222 -- for implicit conversions???).
14223 --
14224 -- Do not treat a rewritten 'Old attribute reference like other
14225 -- rewrite substitutions. This makes a difference, for example,
14226 -- in the case where we are generating the expansion of a
14227 -- membership test of the form
14228 -- Saooaaat'Old in Named_Access_Type
14229 -- because in this case Valid_Conversion needs to return True
14230 -- (otherwise the expansion will be False - see the call site
14231 -- in exp_ch4.adb).
14239 then
14242 -- When applying restriction No_Dynamic_Accessibility_Check,
14243 -- implicit conversions are allowed when the operand type is
14244 -- not deeper than the target type.
14249 then
14250 Conversion_Error_N
14254 -- Implicit conversions aren't allowed for objects of an
14255 -- anonymous access type, since such objects have nonstatic
14256 -- levels in Ada 2012.
14259 = N_Object_Declaration
14260 then
14261 Conversion_Error_N
14266 -- Implicit conversions aren't allowed for anonymous access
14267 -- parameters. We exclude anonymous access results as well
14268 -- as universal_access "=".
14272 N_Function_Specification |
14273 N_Procedure_Specification
14275 then
14276 Conversion_Error_N
14281 -- Detect access discriminant values that are illegal
14282 -- implicit anonymous-to-named access conversion operands.
14285 then
14286 Conversion_Error_N
14291 -- In other cases, the level of the operand's type must be
14292 -- statically less deep than that of the target type, else
14293 -- implicit conversion is disallowed (by RM12-8.6(27.1/3)).
14297 then
14298 Conversion_Error_N
14305 -- Check if the operand is deeper than the target type, taking
14306 -- care to avoid the case where we are converting a result of a
14307 -- function returning an anonymous access type since the "master
14308 -- of the call" would be target type of the conversion unless
14309 -- the target type is anonymous access as well - see RM 3.10.2
14310 -- (10.3/3).
14312 -- Note that when the restriction No_Dynamic_Accessibility_Checks
14313 -- is in effect wei also want to proceed with the conversion check
14314 -- described above.
14319 /= N_Function_Specification
14323 -- Check we are not in a return value ???
14326 or else
14329 then
14330 -- In an instance, this is a run-time check, but one we know
14331 -- will fail, so generate an appropriate warning. The raise
14332 -- will be generated by Expand_N_Type_Conversion.
14336 Conversion_Error_N
14338 Operand);
14341 -- If not in an instance body, this is a real error
14343 else
14344 -- Avoid generation of spurious error message
14347 Conversion_Error_N
14349 Operand);
14355 -- Special accessibility checks are needed in the case of access
14356 -- discriminants declared for a limited type.
14360 then
14361 -- When the operand is a selected access discriminant the check
14362 -- needs to be made against the level of the object denoted by
14363 -- the prefix of the selected name (Accessibility_Level handles
14364 -- checking the prefix of the operand for this case).
14367 and then Static_Accessibility_Level
14370 then
14371 -- In an instance, this is a run-time check, but one we know
14372 -- will fail, so generate an appropriate warning. The raise
14373 -- will be generated by Expand_N_Type_Conversion.
14377 Conversion_Error_N
14382 -- If not in an instance body, this is a real error
14384 else
14385 Conversion_Error_N
14392 -- The case of a reference to an access discriminant from
14393 -- within a limited type declaration (which will appear as
14394 -- a discriminal) is always illegal because the level of the
14395 -- discriminant is considered to be deeper than any (nameable)
14396 -- access type.
14399 and then
14402 then
14403 Conversion_Error_N
14405 Operand);
14411 -- In the presence of limited_with clauses we have to use nonlimited
14412 -- views, if available.
14416 -- Helper function to handle limited views
14418 --------------------------
14419 -- Full_Designated_Type --
14420 --------------------------
14425 begin
14426 -- Handle the limited view of a type
14430 then
14432 else
14437 -- Local Declarations
14445 -- Start of processing for Check_Limited
14447 begin
14451 else
14453 Conversion_Error_NE
14458 -- Ada 2005 AI-384: legality rule is symmetric in both
14459 -- designated types. The conversion is legal (with possible
14460 -- constraint check) if either designated type is
14461 -- unconstrained.
14464 or else
14466 and then
14469 then
14470 -- Special case, if Value_Size has been used to make the
14471 -- sizes different, the conversion is not allowed even
14472 -- though the subtypes statically match.
14477 then
14478 Conversion_Error_NE
14481 Conversion_Error_NE
14486 -- Normal case where conversion is allowed
14488 else
14492 else
14493 Error_Msg_NE
14501 -- Access to subprogram types. If the operand is an access parameter,
14502 -- the type has a deeper accessibility that any master, and cannot be
14503 -- assigned. We must make an exception if the conversion is part of an
14504 -- assignment and the target is the return object of an extended return
14505 -- statement, because in that case the accessibility check takes place
14506 -- after the return.
14510 -- Note: this test of Opnd_Type is there to prevent entering this
14511 -- branch in the case of a remote access to subprogram type, which
14512 -- is internally represented as an E_Record_Type.
14515 then
14519 and then
14523 then
14524 Conversion_Error_N
14526 Operand);
14527 Conversion_Error_N
14530 Operand);
14532 Error_Msg_NE
14537 -- Check that the designated types are subtype conformant
14543 -- Check the static accessibility rule of 4.6(20)
14547 then
14548 Conversion_Error_N
14550 Operand);
14552 -- Check that if the operand type is declared in a generic body,
14553 -- then the target type must be declared within that same body
14554 -- (enforces last sentence of 4.6(20)).
14557 declare
14563 begin
14570 Conversion_Error_N
14577 -- Check that the strub modes are compatible.
14578 -- We wish to reject explicit conversions only for
14579 -- incompatible modes.
14581 return Conversion_Check
14582 (Compatible_Strub_Modes
14587 -- Remote access to subprogram types
14591 then
14592 -- It is valid to convert from one RAS type to another provided
14593 -- that their specification statically match.
14595 -- Note: at this point, remote access to subprogram types have been
14596 -- expanded to their E_Record_Type representation, and we need to
14597 -- go back to the original access type definition using the
14598 -- Corresponding_Remote_Type attribute in order to check that the
14599 -- designated profiles match.
14604 Check_Subtype_Conformant
14607 Old_Id =>
14609 Err_Loc =>
14610 N);
14612 -- Check that the strub modes are compatible.
14613 -- We wish to reject explicit conversions only for
14614 -- incompatible modes.
14616 return Conversion_Check
14617 (Compatible_Strub_Modes
14622 -- If it was legal in the generic, it's legal in the instance
14627 -- If both are tagged types, check legality of view conversions
14630 and then
14632 then
14635 -- Types derived from the same root type are convertible
14640 -- In an instance or an inlined body, there may be inconsistent views of
14641 -- the same type, or of types derived from a common root.
14644 and then
14647 then
14650 -- Special check for common access type error case
14654 then
14656 Conversion_Error_NE -- CODEFIX
14660 -- Here we have a real conversion error
14662 else
14663 -- Check for missing regular with_clause when only a limited view of
14664 -- target is available.
14667 Conversion_Error_NE
14670 Conversion_Error_NE
14675 and then In_Package_Body
14676 then
14677 Conversion_Error_NE
14679 Conversion_Error_NE
14683 else
14684 Conversion_Error_NE