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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) 1992-2023, 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 ------------------------------------------------------------------------------
98 -----------------------
99 -- Local Subprograms --
100 -----------------------
102 -- Second pass (top-down) type checking and overload resolution procedures
103 -- Typ is the type required by context. These procedures propagate the
104 -- type information recursively to the descendants of N. If the node is not
105 -- overloaded, its Etype is established in the first pass. If overloaded,
106 -- the Resolve routines set the correct type. For arithmetic operators, the
107 -- Etype is the base type of the context.
109 -- Note that Resolve_Attribute is separated off in Sem_Attr
111 function Has_Applicable_User_Defined_Literal
114 -- Check whether N is a literal or a named number, and whether Typ has a
115 -- user-defined literal aspect that may apply to N. In this case, replace
116 -- N with a call to the corresponding function and return True.
119 -- Enforce the restrictions on the use of discriminants when constraining
120 -- a component of a discriminated type (record or concurrent type).
123 -- Given a node for an operator associated with type T, check that the
124 -- operator is visible. Operators all of whose operands are universal must
125 -- be checked for visibility during resolution because their type is not
126 -- determinable based on their operands.
128 procedure Check_Fully_Declared_Prefix
131 -- Check that the type of the prefix of a dereference is not incomplete
134 -- Given a call node, Call, which is known to occur immediately within the
135 -- subprogram being called, determines whether it is a detectable case of
136 -- an infinite recursion, and if so, outputs appropriate messages. Returns
137 -- True if an infinite recursion is detected, and False otherwise.
140 -- N is the node for a logical operator. If the operator is predefined, and
141 -- the root type of the operands is Standard.Boolean, then a check is made
142 -- for restriction No_Direct_Boolean_Operators. This procedure also handles
143 -- the style check for Style_Check_Boolean_And_Or.
146 -- N is either an indexed component or a selected component. This function
147 -- returns true if the prefix denotes an atomic object that has an address
148 -- clause (the case in which we may want to issue a warning).
151 -- Determine whether E is an access type declared by an access declaration,
152 -- and not an (anonymous) allocator type.
155 -- Utility to check whether the entity for an operator is a predefined
156 -- operator, in which case the expression is left as an operator in the
157 -- tree (else it is rewritten into a call). An instance of an intrinsic
158 -- conversion operation may be given an operator name, but is not treated
159 -- like an operator. Note that an operator that is an imported back-end
160 -- builtin has convention Intrinsic, but is expected to be rewritten into
161 -- a call, so such an operator is not treated as predefined by this
162 -- predicate.
164 procedure Preanalyze_And_Resolve
168 -- Subsidiary of public versions of Preanalyze_And_Resolve.
171 -- If a default expression in entry call N depends on the discriminants
172 -- of the task, it must be replaced with a reference to the discriminant
173 -- of the task being called.
175 procedure Resolve_Dependent_Expression
179 -- Internal procedure to resolve the dependent expression Expr of the
180 -- conditional expression N with type Typ.
182 procedure Resolve_Op_Concat_Arg
187 -- Internal procedure for Resolve_Op_Concat to resolve one operand of
188 -- concatenation operator. The operand is either of the array type or of
189 -- the component type. If the operand is an aggregate, and the component
190 -- type is composite, this is ambiguous if component type has aggregates.
193 -- Does the first part of the work of Resolve_Op_Concat
196 -- Does the "rest" of the work of Resolve_Op_Concat, after the left operand
197 -- has been resolved. See Resolve_Op_Concat for details.
214 procedure Resolve_Interpolated_String_Literal
240 function Operator_Kind
243 -- Utility to map the name of an operator into the corresponding Node. Used
244 -- by other node rewriting procedures.
247 -- Resolve actuals of call, and add default expressions for missing ones.
248 -- N is the Node_Id for the subprogram call, and Nam is the entity of the
249 -- called subprogram.
252 -- Called from Resolve_Call, when the prefix denotes an entry or element
253 -- of entry family. Actuals are resolved as for subprograms, and the node
254 -- is rebuilt as an entry call. Also called for protected operations. Typ
255 -- is the context type, which is used when the operation is a protected
256 -- function with no arguments, and the return value is indexed.
259 -- Called when P is the prefix of an indexed component, or of a selected
260 -- component, or of a slice. If P is of an access type, we unconditionally
261 -- rewrite it as an explicit dereference. This ensures that the expander
262 -- and the code generator have a fully explicit tree to work with.
265 -- A call to a user-defined intrinsic operator is rewritten as a call to
266 -- the corresponding predefined operator, with suitable conversions. Note
267 -- that this applies only for intrinsic operators that denote predefined
268 -- operators, not ones that are intrinsic imports of back-end builtins.
271 -- Ditto, for arithmetic unary operators
274 -- If an operator node resolves to a call to a user-defined operator,
275 -- rewrite the node as a function call.
277 procedure Make_Call_Into_Operator
281 -- Inverse transformation: if an operator is given in functional notation,
282 -- then after resolving the node, transform into an operator node, so that
283 -- operands are resolved properly. Recall that predefined operators do not
284 -- have a full signature and special resolution rules apply.
286 procedure Rewrite_Renamed_Operator
290 -- An operator can rename another, e.g. in an instantiation. In that
291 -- case, the proper operator node must be constructed and resolved.
294 -- The String_Literal_Subtype is built for all strings that are not
295 -- operands of a static concatenation operation. If the argument is not
296 -- a N_String_Literal node, then the call has no effect.
299 -- Build subtype of array type, with the range specified by the slice
302 -- Called after N has been resolved and evaluated, but before range checks
303 -- have been applied. This rewrites the conversion into a simpler form.
305 function Try_User_Defined_Literal
308 -- If the node is a literal or a named number or a conditional expression
309 -- whose dependent expressions are all literals or named numbers, and the
310 -- context type has a user-defined literal aspect, then rewrite the node
311 -- or its leaf nodes as calls to the corresponding function, which plays
312 -- the role of an implicit conversion.
314 function Try_User_Defined_Literal_For_Operator
317 -- If an operator node has a literal operand, check whether the type of the
318 -- context, or that of the other operand has a user-defined literal aspect
319 -- that can be applied to the literal to resolve the node. If such aspect
320 -- exists, replace literal with a call to the corresponding function and
321 -- return True, return false otherwise.
324 -- A universal_fixed expression in an universal context is unambiguous if
325 -- there is only one applicable fixed point type. Determining whether there
326 -- is only one requires a search over all visible entities, and happens
327 -- only in very pathological cases (see 6115-006).
329 -------------------------
330 -- Ambiguous_Character --
331 -------------------------
336 begin
340 -- First the ones in Standard
345 -- Include Wide_Wide_Character in Ada 2005 mode
351 -- Now any other types that match
361 -------------------------
362 -- Analyze_And_Resolve --
363 -------------------------
366 begin
372 begin
377 -- Versions with check(s) suppressed
379 procedure Analyze_And_Resolve
383 is
386 begin
388 declare
390 begin
396 else
397 declare
399 begin
407 and then Scope_Is_Transient
408 then
409 -- This can only happen if a transient scope was created for an inner
410 -- expression, which will be removed upon completion of the analysis
411 -- of an enclosing construct. The transient scope must have the
412 -- suppress status of the enclosing environment, not of this Analyze
413 -- call.
416 Scope_Suppress;
420 procedure Analyze_And_Resolve
423 is
426 begin
428 declare
430 begin
436 else
437 declare
439 begin
448 Scope_Suppress;
452 -------------------------------------
453 -- Has_Applicable_User_Defined_Literal --
454 -------------------------------------
456 function Has_Applicable_User_Defined_Literal
459 is
461 Literal_Aspect_Map :
482 begin
484 and then Present
486 or else
489 and then
490 Present
491 (Find_Aspect
493 then
494 Lit_Aspect :=
498 Callee :=
504 then
505 Callee :=
506 Corresponding_Primitive_Op
511 -- Handle an identifier that denotes a named number.
518 Start_String;
519 Store_String_Chars
524 else
526 Start_String;
532 Store_String_Chars
536 -- Note: Set_Etype is called below on Param1
539 Start_String;
540 Store_String_Chars
549 else
550 Error_Msg_NE
560 else
561 Param1 :=
562 Make_String_Literal
567 Call :=
568 Make_Function_Call
578 else
584 -- Conversion not needed if the result type of the call is class-wide
585 -- or if the result type matches the context type.
589 then
590 -- Conversion may be needed in case of an inherited
591 -- aspect of a derived type. For a null extension, we
592 -- use a null extension aggregate instead because the
593 -- downward type conversion would be illegal.
595 if Is_Null_Extension_Of
598 then
602 else
612 else
617 ----------------------------
618 -- Check_Discriminant_Use --
619 ----------------------------
627 begin
628 -- Any use in a spec-expression is legal
635 -- Discriminant cannot be used to constrain a scalar type
642 then
647 -- The following check catches the unusual case where a
648 -- discriminant appears within an index constraint that is part
649 -- of a larger expression within a constraint on a component,
650 -- e.g. "C : Int range 1 .. F (new A(1 .. D))". For now we only
651 -- check case of record components, and note that a similar check
652 -- should also apply in the case of discriminant constraints
653 -- below. ???
655 -- Note that the check for N_Subtype_Declaration below is to
656 -- detect the valid use of discriminants in the constraints of a
657 -- subtype declaration when this subtype declaration appears
658 -- inside the scope of a record type (which is syntactically
659 -- illegal, but which may be created as part of derived type
660 -- processing for records). See Sem_Ch3.Build_Derived_Record_Type
661 -- for more info.
665 and then not
667 and then
669 | N_Subtype_Declaration
671 then
672 Error_Msg_N
677 -- Detect a common error:
679 -- type R (D : Positive := 100) is record
680 -- Name : String (1 .. D);
681 -- end record;
683 -- The default value causes an object of type R to be allocated
684 -- with room for Positive'Last characters. The RM does not mandate
685 -- the allocation of the maximum size, but that is what GNAT does
686 -- so we should warn the programmer that there is a problem.
695 -- Return True if type T has a large enough range that any
696 -- array whose index type covered the whole range of the type
697 -- would likely raise Storage_Error.
699 ------------------------
700 -- Large_Storage_Type --
701 ------------------------
704 begin
705 -- The type is considered large if its bounds are known at
706 -- compile time and if it requires at least as many bits as
707 -- a Positive to store the possible values.
711 and then
716 -- Start of processing for Check_Large
718 begin
719 -- Check that the Disc has a large range
725 -- If the enclosing type is limited, we allocate only the
726 -- default value, not the maximum, and there is no need for
727 -- a warning.
733 -- Check that it is the high bound
737 then
741 -- Check the array allows a large range at this bound. First
742 -- find the array
756 -- Next, find the dimension
764 loop
773 -- Now, check the dimension has a large range
779 -- Warn about the danger
781 Error_Msg_N
791 -- Legal case is in index or discriminant constraint
794 | N_Discriminant_Association
795 then
797 Error_Msg_N
802 then
803 Error_Msg_N
809 -- Otherwise, context is an expression. It should not be within (i.e. a
810 -- subexpression of) a constraint for a component.
812 else
816 N_Component_Declaration | N_Subtype_Indication | N_Entry_Declaration
817 loop
823 -- If the discriminant is used in an expression that is a bound of a
824 -- scalar type, an Itype is created and the bounds are attached to
825 -- its range, not to the original subtype indication. Such use is of
826 -- course a double fault.
830 | N_Derived_Type_Definition
833 -- The constraint itself may be given by a subtype indication,
834 -- rather than by a more common discrete range.
837 and then
841 then
842 Error_Msg_N
848 --------------------------------
849 -- Check_For_Visible_Operator --
850 --------------------------------
853 begin
857 then
858 Error_Msg_NE -- CODEFIX
860 Error_Msg_N -- CODEFIX
865 ---------------------------------
866 -- Check_Fully_Declared_Prefix --
867 ---------------------------------
869 procedure Check_Fully_Declared_Prefix
872 is
873 begin
874 -- Check that the designated type of the prefix of a dereference is
875 -- not an incomplete type. This cannot be done unconditionally, because
876 -- dereferences of private types are legal in default expressions. This
877 -- case is taken care of in Check_Fully_Declared, called below. There
878 -- are also 2005 cases where it is legal for the prefix to be unfrozen.
880 -- This consideration also applies to similar checks for allocators,
881 -- qualified expressions, and type conversions.
883 -- An additional exception concerns other per-object expressions that
884 -- are not directly related to component declarations, in particular
885 -- representation pragmas for tasks. These will be per-object
886 -- expressions if they depend on discriminants or some global entity.
887 -- If the task has access discriminants, the designated type may be
888 -- incomplete at the point the expression is resolved. This resolution
889 -- takes place within the body of the initialization procedure, where
890 -- the discriminant is replaced by its discriminal.
894 then
897 -- Ada 2005 (AI-326): Tagged incomplete types allowed. The wrong usages
898 -- are handled by Analyze_Access_Attribute, Analyze_Assignment,
899 -- Analyze_Object_Renaming, and Freeze_Entity.
905 E_Incomplete_Type
907 then
909 else
914 ------------------------------
915 -- Check_Infinite_Recursion --
916 ------------------------------
920 -- Determine whether call N invokes the related enclosing subprogram
921 -- with actuals that differ from the subprogram's formals.
924 -- Determine whether arbitrary node N denotes a conditional construct
927 -- Determine whether arbitrary node N denotes a control flow statement
928 -- or a construct that may contains such a statement.
931 -- Determine whether arbitrary node N appears immediately within the
932 -- statements of an entry or subprogram body.
935 -- Determine whether arbitrary node N appears immediately within the
936 -- body of an entry or subprogram, and is preceded by a single raise
937 -- statement.
940 -- Determine whether arbitrary node N denotes a raise statement
943 -- Determine whether arbitrary node N is the sole source statement in
944 -- the body of the enclosing subprogram.
947 -- Determine whether arbitrary node N is preceded by a control flow
948 -- statement.
951 -- Determine whether arbitrary node N appears within a conditional
952 -- construct.
954 --------------------------------------
955 -- Invoked_With_Different_Arguments --
956 --------------------------------------
964 begin
965 -- Determine whether the formals of the invoked subprogram are not
966 -- used as actuals in the call.
972 -- The current actual does not match the current formal
976 then
987 ------------------------------
988 -- Is_Conditional_Statement --
989 ------------------------------
992 begin
993 return
995 | N_Case_Expression
996 | N_Case_Statement
997 | N_If_Expression
998 | N_If_Statement
999 | N_Or_Else;
1002 -------------------------------
1003 -- Is_Control_Flow_Statement --
1004 -------------------------------
1007 begin
1008 -- It is assumed that all statements may affect the control flow in
1009 -- some way. A raise statement may be expanded into a non-statement
1010 -- node.
1015 --------------------------------
1016 -- Is_Immediately_Within_Body --
1017 --------------------------------
1022 begin
1023 return
1030 --------------------
1031 -- Is_Raise_Idiom --
1032 --------------------
1038 begin
1041 -- Assume that no raise statement has been seen yet
1045 -- Examine the statements preceding the input node, skipping
1046 -- internally-generated constructs.
1051 -- Multiple raise statements violate the idiom
1067 -- At this point the node must be preceded by a raise statement,
1068 -- and the raise statement has to be the sole statement within
1069 -- the enclosing entry or subprogram body.
1071 return
1078 ------------------------
1079 -- Is_Raise_Statement --
1080 ------------------------
1083 begin
1084 -- A raise statement may be transfomed into a Raise_xxx_Error node
1086 return
1091 -----------------------
1092 -- Is_Sole_Statement --
1093 -----------------------
1098 begin
1099 -- The input node appears within the statements of an entry or
1100 -- subprogram body. Examine the statements preceding the node.
1107 -- The statement is preceded by another statement or a source
1108 -- construct. This indicates that the node does not appear by
1109 -- itself.
1113 then
1123 -- The input node is within a construct nested inside the entry or
1124 -- subprogram body.
1129 ----------------------------------------
1130 -- Preceded_By_Control_Flow_Statement --
1131 ----------------------------------------
1133 function Preceded_By_Control_Flow_Statement
1135 is
1138 begin
1142 -- Examine the statements preceding the input node
1155 -- Assume that the node is part of some control flow statement
1160 ----------------------------------
1161 -- Within_Conditional_Statement --
1162 ----------------------------------
1167 begin
1173 -- Prevent the search from going too far
1185 -- Local variables
1190 -- Start of processing for Check_Infinite_Recursion
1192 begin
1193 -- The call is assumed to be safe when the enclosing subprogram is
1194 -- invoked with actuals other than its formals.
1195 --
1196 -- procedure Proc (F1 : ...; F2 : ...; ...; FN : ...) is
1197 -- begin
1198 -- ...
1199 -- Proc (A1, A2, ..., AN);
1200 -- ...
1201 -- end Proc;
1206 -- The call is assumed to be safe when the invocation of the enclosing
1207 -- subprogram depends on a conditional statement.
1208 --
1209 -- procedure Proc (F1 : ...; F2 : ...; ...; FN : ...) is
1210 -- begin
1211 -- ...
1212 -- if Some_Condition then
1213 -- Proc (F1, F2, ..., FN);
1214 -- end if;
1215 -- ...
1216 -- end Proc;
1221 -- The context of the call is assumed to be safe when the invocation of
1222 -- the enclosing subprogram is preceded by some control flow statement.
1223 --
1224 -- procedure Proc (F1 : ...; F2 : ...; ...; FN : ...) is
1225 -- begin
1226 -- ...
1227 -- if Some_Condition then
1228 -- ...
1229 -- end if;
1230 -- ...
1231 -- Proc (F1, F2, ..., FN);
1232 -- ...
1233 -- end Proc;
1238 -- Detect an idiom where the context of the call is preceded by a single
1239 -- raise statement.
1240 --
1241 -- procedure Proc (F1 : ...; F2 : ...; ...; FN : ...) is
1242 -- begin
1243 -- raise ...;
1244 -- Proc (F1, F2, ..., FN);
1245 -- end Proc;
1251 -- At this point it is certain that infinite recursion will take place
1252 -- as long as the call is executed. Detect a case where the context of
1253 -- the call is the sole source statement within the subprogram body.
1254 --
1255 -- procedure Proc (F1 : ...; F2 : ...; ...; FN : ...) is
1256 -- begin
1257 -- Proc (F1, F2, ..., FN);
1258 -- end Proc;
1259 --
1260 -- Install an explicit raise to prevent the infinite recursion.
1271 -- Otherwise infinite recursion could take place, considering other flow
1272 -- control constructs such as gotos, exit statements, etc.
1274 else
1283 ---------------------------------------
1284 -- Check_No_Direct_Boolean_Operators --
1285 ---------------------------------------
1288 begin
1291 then
1292 -- Restriction only applies to original source code
1299 -- Do style check (but skip if in instance, error is on template)
1308 ------------------------------
1309 -- Check_Parameterless_Call --
1310 ------------------------------
1316 -- If the prefix is of an access_to_subprogram type, the node must be
1317 -- rewritten as a call. Ditto if the prefix is overloaded and all its
1318 -- interpretations are access to subprograms.
1320 ---------------------------
1321 -- Prefix_Is_Access_Subp --
1322 ---------------------------
1328 begin
1329 -- If the context is an attribute reference that can apply to
1330 -- functions, this is never a parameterless call (RM 4.1.4(6)).
1334 in Name_Address | Name_Code_Address | Name_Access
1335 then
1340 return
1343 else
1348 then
1359 -- Start of processing for Check_Parameterless_Call
1361 begin
1362 -- Defend against junk stuff if errors already detected
1369 then
1376 -- If the context expects a value, and the name is a procedure, this is
1377 -- most likely a missing 'Access. Don't try to resolve the parameterless
1378 -- call, error will be caught when the outer call is analyzed.
1383 and then
1385 | N_Function_Call
1386 | N_Procedure_Call_Statement
1387 then
1391 -- Rewrite as call if overloadable entity that is (or could be, in the
1392 -- overloaded case) a function call. If we know for sure that the entity
1393 -- is an enumeration literal, we do not rewrite it.
1395 -- If the entity is the name of an operator, it cannot be a call because
1396 -- operators cannot have default parameters. In this case, this must be
1397 -- a string whose contents coincide with an operator name. Set the kind
1398 -- of the node appropriately.
1406 -- Rewrite as call if it is an explicit dereference of an expression of
1407 -- a subprogram access type, and the subprogram type is not that of a
1408 -- procedure or entry.
1410 or else
1413 -- Rewrite as call if it is a selected component which is a function,
1414 -- this is the case of a call to a protected function (which may be
1415 -- overloaded with other protected operations).
1417 or else
1420 or else
1422 E_Entry | E_Procedure
1425 -- If one of the above three conditions is met, rewrite as call. Apply
1426 -- the rewriting only once.
1428 then
1431 then
1433 -- This may be a prefixed call that was not fully analyzed, e.g.
1434 -- an actual in an instance.
1439 then
1447 -- The node is the name of the parameterless call. Preserve its
1448 -- descendants, which may be complex expressions.
1452 -- If overloaded, overload set belongs to new copy
1456 -- Change node to parameterless function call (note that the
1457 -- Parameter_Associations associations field is left set to Empty,
1458 -- its normal default value since there are no parameters)
1478 --------------------------------
1479 -- Is_Atomic_Ref_With_Address --
1480 --------------------------------
1485 begin
1489 else
1490 declare
1493 begin
1501 -----------------------------
1502 -- Is_Definite_Access_Type --
1503 -----------------------------
1507 begin
1513 ----------------------
1514 -- Is_Predefined_Op --
1515 ----------------------
1518 begin
1519 -- Predefined operators are intrinsic subprograms
1525 -- A call to a back-end builtin is never a predefined operator
1536 -----------------------------
1537 -- Make_Call_Into_Operator --
1538 -----------------------------
1540 procedure Make_Call_Into_Operator
1544 is
1559 -- If the operand is not universal, and the operator is given by an
1560 -- expanded name, verify that the operand has an interpretation with a
1561 -- type defined in the given scope of the operator.
1564 -- Find a type of the given class in package Pack that contains the
1565 -- operator.
1567 ---------------------------
1568 -- Operand_Type_In_Scope --
1569 ---------------------------
1576 begin
1580 else
1594 ---------------
1595 -- Type_In_P --
1596 ---------------
1602 -- Verify that node is not part of the type declaration for the
1603 -- candidate type, which would otherwise be invisible.
1605 -------------
1606 -- In_Decl --
1607 -------------
1613 begin
1622 else
1625 loop
1628 else
1637 -- Start of processing for Type_In_P
1639 begin
1640 -- If the context type is declared in the prefix package, this is the
1641 -- desired base type.
1646 else
1660 -- Start of processing for Make_Call_Into_Operator
1662 begin
1665 -- Preserve the Comes_From_Source flag on the result if the original
1666 -- call came from source. Although it is not strictly the case that the
1667 -- operator as such comes from the source, logically it corresponds
1668 -- exactly to the function call in the source, so it should be marked
1669 -- this way (e.g. to make sure that validity checks work fine).
1673 -- Ensure that the corresponding operator has the same parent as the
1674 -- original call. This guarantees that parent traversals performed by
1675 -- the ABE mechanism succeed.
1679 -- Binary operator
1689 -- Unary operator
1691 else
1697 -- If the operator is denoted by an expanded name, and the prefix is
1698 -- not Standard, but the operator is a predefined one whose scope is
1699 -- Standard, then this is an implicit_operator, inserted as an
1700 -- interpretation by the procedure of the same name. This procedure
1701 -- overestimates the presence of implicit operators, because it does
1702 -- not examine the type of the operands. Verify now that the operand
1703 -- type appears in the given scope. If right operand is universal,
1704 -- check the other operand. In the case of concatenation, either
1705 -- argument can be the component type, so check the type of the result.
1706 -- If both arguments are literals, look for a type of the right kind
1707 -- defined in the given scope. This elaborate nonsense is brought to
1708 -- you courtesy of b33302a. The type itself must be frozen, so we must
1709 -- find the type of the proper class in the given scope.
1711 -- A final wrinkle is the multiplication operator for fixed point types,
1712 -- which is defined in Standard only, and not in the scope of the
1713 -- fixed point type itself.
1718 -- If this is a package renaming, get renamed entity, which will be
1719 -- the scope of the operands if operaton is type-correct.
1725 -- If the entity being called is defined in the given package, it is
1726 -- a renaming of a predefined operator, and known to be legal.
1730 then
1733 -- Visibility does not need to be checked in an instance: if the
1734 -- operator was not visible in the generic it has been diagnosed
1735 -- already, else there is an implicit copy of it in the instance.
1743 then
1748 -- Ada 2005 AI-420: Predefined equality on Universal_Access is
1749 -- available.
1755 then
1758 else
1767 and then Is_Binary
1769 then
1775 -- Verify that the scope contains a type that corresponds to
1776 -- the given literal. Optimize the case where Pack is Standard.
1797 else
1806 else
1815 then
1818 -- If the type is defined elsewhere, and the operator is not
1819 -- defined in the given scope (by a renaming declaration, e.g.)
1820 -- then this is an error as well. If an extension of System is
1821 -- present, and the type may be defined there, Pack must be
1822 -- System itself.
1829 then
1832 else
1838 then
1845 Error_Msg_NE
1850 -- Detect a mismatch between the context type and the result type
1851 -- in the named package, which is otherwise not detected if the
1852 -- operands are universal. Check is only needed if source entity is
1853 -- an operator, not a function that renames an operator.
1860 and then not In_Instance
1861 then
1864 then
1865 -- Already checked above
1869 -- Operator may be defined in an extension of System
1874 then
1877 else
1878 -- Could we use Wrong_Type here??? (this would require setting
1879 -- Etype (N) to the actual type found where Typ was expected).
1890 else
1894 -- If this is a call to a function that renames a predefined equality,
1895 -- the renaming declaration provides a type that must be used to
1896 -- resolve the operands. This must be done now because resolution of
1897 -- the equality node will not resolve any remaining ambiguity, and it
1898 -- assumes that the first operand is not overloaded.
1903 then
1913 -- If this is an arithmetic operator and the result type is private,
1914 -- the operands and the result must be wrapped in conversion to
1915 -- expose the underlying numeric type and expand the proper checks,
1916 -- e.g. on division.
1920 when N_Op_Add
1921 | N_Op_Divide
1922 | N_Op_Expon
1923 | N_Op_Mod
1924 | N_Op_Multiply
1925 | N_Op_Rem
1926 | N_Op_Subtract
1927 =>
1930 when N_Op_Abs
1931 | N_Op_Minus
1932 | N_Op_Plus
1933 =>
1939 else
1944 -------------------
1945 -- Operator_Kind --
1946 -------------------
1948 function Operator_Kind
1951 is
1954 begin
1955 -- Use CASE statement or array???
1992 else
1996 -- Unary operators
1998 else
2007 else
2015 ----------------------------
2016 -- Preanalyze_And_Resolve --
2017 ----------------------------
2019 procedure Preanalyze_And_Resolve
2023 is
2027 Inside_Preanalysis_Without_Freezing;
2028 begin
2033 Inside_Preanalysis_Without_Freezing :=
2040 -- See also Preanalyze_And_Resolve in sem.adb for similar handling
2042 -- Normally, we suppress all checks for this preanalysis. There is no
2043 -- point in processing them now, since they will be applied properly
2044 -- and in the proper location when the default expressions reanalyzed
2045 -- and reexpanded later on. We will also have more information at that
2046 -- point for possible suppression of individual checks.
2048 -- However, in GNATprove mode, most expansion is suppressed, and this
2049 -- later reanalysis and reexpansion may not occur. GNATprove mode does
2050 -- require the setting of checking flags for proof purposes, so we
2051 -- do the GNATprove preanalysis without suppressing checks.
2053 -- This special handling for SPARK mode is required for example in the
2054 -- case of Ada 2012 constructs such as quantified expressions, which are
2055 -- expanded in two separate steps.
2057 -- We also do not want to suppress checks if we are not dealing
2058 -- with a default expression. One such case that is known to reach
2059 -- this point is the expression of an expression function.
2063 else
2067 Expander_Mode_Restore;
2072 Inside_Preanalysis_Without_Freezing :=
2076 pragma Assert
2080 ----------------------------
2081 -- Preanalyze_And_Resolve --
2082 ----------------------------
2085 begin
2089 -- Version without context type
2094 begin
2101 Expander_Mode_Restore;
2105 ------------------------------------------
2106 -- Preanalyze_With_Freezing_And_Resolve --
2107 ------------------------------------------
2109 procedure Preanalyze_With_Freezing_And_Resolve
2112 is
2113 begin
2117 ----------------------------------
2118 -- Replace_Actual_Discriminants --
2119 ----------------------------------
2126 -- Comment needed???
2128 -------------------
2129 -- Process_Discr --
2130 -------------------
2135 begin
2141 then
2157 -- Start of processing for Replace_Actual_Discriminants
2159 begin
2163 -- Allow the replacement of concurrent discriminants in GNATprove even
2164 -- though this is a light expansion activity. Note that generic units
2165 -- are not modified.
2170 else
2186 -------------
2187 -- Resolve --
2188 -------------
2204 -- Determine whether a node comes from a predefined library unit or
2205 -- Standard.
2208 -- Try and fix up a literal so that it matches its expected type. New
2209 -- literals are manufactured if necessary to avoid cascaded errors.
2212 -- Additional diagnostics when an ambiguous call has an ambiguous
2213 -- argument (typically a controlling actual).
2216 -- Called when attempt at resolving current expression fails
2218 ------------------------------------
2219 -- Comes_From_Predefined_Lib_Unit --
2220 -------------------------------------
2223 begin
2224 return
2228 --------------------
2229 -- Patch_Up_Value --
2230 --------------------
2233 begin
2250 then
2255 Char_Literal_Value =>
2271 -------------------------------
2272 -- Report_Ambiguous_Argument --
2273 -------------------------------
2280 begin
2284 then
2287 -- Examine possible interpretations, and adapt the message
2288 -- for inherited subprograms declared by a type derivation.
2296 else
2304 -- Additional message and hint if the ambiguity involves an Ada 2022
2305 -- container aggregate.
2310 -----------------------
2311 -- Resolution_Failed --
2312 -----------------------
2315 begin
2318 -- Set the type to the desired one to minimize cascaded errors. Note
2319 -- that this is an approximation and does not work in all cases.
2326 -- The caller will return without calling the expander, so we need
2327 -- to set the analyzed flag. Note that it is fine to set Analyzed
2328 -- to True even if we are in the middle of a shallow analysis,
2329 -- (see the spec of sem for more details) since this is an error
2330 -- situation anyway, and there is no point in repeating the
2331 -- analysis later (indeed it won't work to repeat it later, since
2332 -- we haven't got a clear resolution of which entity is being
2333 -- referenced.)
2339 -- Start of processing for Resolve
2341 begin
2346 -- Access attribute on remote subprogram cannot be used for a non-remote
2347 -- access-to-subprogram type.
2351 | Name_Unrestricted_Access
2352 | Name_Unchecked_Access
2358 then
2359 Error_Msg_N
2363 -- If the context is a Remote_Access_To_Subprogram, access attributes
2364 -- must be resolved with the corresponding fat pointer. There is no need
2365 -- to check for the attribute name since the return type of an
2366 -- attribute is never a remote type.
2371 then
2372 declare
2380 begin
2381 -- Check that Typ is a remote access-to-subprogram type
2385 -- Prefix (N) must statically denote a remote subprogram
2386 -- declared in a package specification.
2390 Attr = Attribute_Unrestricted_Access
2391 then
2406 or else
2408 then
2410 Error_Msg_N
2412 N);
2415 -- If we are generating code in distributed mode, perform
2416 -- semantic checks against corresponding remote entities.
2418 if Expander_Active
2420 then
2421 Check_Subtype_Conformant
2423 Old_Id => Designated_Type
2449 then
2454 -- Return if already analyzed
2461 -- Any case of Any_Type as the Etype value means that we had a
2462 -- previous error.
2471 -- The resolution of an Expression_With_Actions is determined by
2472 -- its Expression, but if the node comes from source it is a
2473 -- Declare_Expression and requires scope management.
2478 else
2485 -- The resolution of a conditional expression that is the operand of a
2486 -- type conversion is determined by the conversion (RM 4.5.7(10/3)).
2490 then
2494 -- If not overloaded, then we know the type, and all that needs doing
2495 -- is to check that this type is compatible with the context. But note
2496 -- that we may have an operator with no interpretation in Ada 2022 for
2497 -- the case of possible user-defined literals as operands.
2503 else
2508 -- In the overloaded case, we must select the interpretation that
2509 -- is compatible with the context (i.e. the type passed to Resolve)
2511 else
2514 -- Loop through possible interpretations
2523 -- We are only interested in interpretations that are compatible
2524 -- with the expected type, any other interpretations are ignored.
2529 Write_Eol;
2532 else
2533 -- Skip the current interpretation if it is disabled by an
2534 -- abstract operator. This action is performed only when the
2535 -- type against which we are resolving is the same as the
2536 -- type of the interpretation.
2542 then
2550 -- First matching interpretation
2558 -- Matching interpretation that is not the first, maybe an
2559 -- error, but there are some cases where preference rules are
2560 -- used to choose between the two possibilities. These and
2561 -- some more obscure cases are handled in Disambiguate.
2563 else
2564 -- If the current statement is part of a predefined library
2565 -- unit, then all interpretations which come from user level
2566 -- packages should not be considered. Check previous and
2567 -- current one.
2575 -- Previous interpretation must be discarded
2585 -- Otherwise apply further disambiguation steps
2590 -- Disambiguation has succeeded. Skip the remaining
2591 -- interpretations.
2601 else
2602 -- Before we issue an ambiguity complaint, check for the
2603 -- case of a subprogram call where at least one of the
2604 -- arguments is Any_Type, and if so suppress the message,
2605 -- since it is a cascaded error. This can also happen for
2606 -- a generalized indexing operation.
2611 then
2612 declare
2616 begin
2632 Write_Eol;
2645 then
2650 then
2654 -- Not that special case, so issue message using the flag
2655 -- Ambiguous to control printing of the header message
2656 -- only at the start of an ambiguous set.
2661 then
2662 Error_Msg_N
2665 else
2666 Error_Msg_NE -- CODEFIX
2674 Error_Msg_N
2676 else
2677 Error_Msg_N -- CODEFIX
2683 then
2684 Report_Ambiguous_Argument;
2690 -- By default, the error message refers to the candidate
2691 -- interpretation. But if it is a predefined operator, it
2692 -- is implicitly declared at the declaration of the type
2693 -- of the operand. Recover the sloc of that declaration
2694 -- for the error message.
2700 Standard_Standard
2701 then
2706 then
2714 Standard_Standard
2715 then
2720 then
2724 -- If this is an indirect call, use the subprogram_type
2725 -- in the message, to have a meaningful location. Also
2726 -- indicate if this is an inherited operation, created
2727 -- by a type declaration.
2732 then
2734 Error_Msg_Sloc :=
2736 else
2743 then
2744 -- Special-case the message for universal_fixed
2745 -- operators, which are not declared with the type
2746 -- of the operand, but appear forever in Standard.
2750 then
2751 Error_Msg_N
2754 else
2755 Error_Msg_N
2759 elsif
2761 then
2762 Error_Msg_N
2764 else
2765 Error_Msg_N -- CODEFIX
2772 -- We have a matching interpretation, Expr_Type is the type
2773 -- from this interpretation, and Seen is the entity.
2775 -- For an operator, just set the entity name. The type will be
2776 -- set by the specific operator resolution routine.
2783 | N_Character_Literal
2784 | N_Delta_Aggregate
2785 | N_If_Expression
2786 then
2789 -- AI05-0139-2: Expression is overloaded because type has
2790 -- implicit dereference. The context may be the one that
2791 -- requires implicit dereferemce.
2797 -- If the expression is an entity, generate a reference
2798 -- to it, as this is not done for an overloaded construct
2799 -- during analysis.
2803 then
2806 -- Examine access discriminants of entity type,
2807 -- to check whether one of them yields the
2808 -- expected type.
2810 declare
2814 begin
2835 then
2836 -- If the node is a general indexing, the dereference is
2837 -- is inserted when resolving the rewritten form, else
2838 -- insert it now.
2842 then
2846 -- For an explicit dereference, attribute reference, range,
2847 -- short-circuit form (which is not an operator node), or call
2848 -- with a name that is an explicit dereference, there is
2849 -- nothing to be done at this point.
2852 | N_And_Then
2853 | N_Explicit_Dereference
2854 | N_Identifier
2855 | N_Indexed_Component
2856 | N_Or_Else
2857 | N_Range
2858 | N_Selected_Component
2859 | N_Slice
2861 then
2864 -- For procedure or function calls, set the type of the name,
2865 -- and also the entity pointer for the prefix.
2869 then
2876 then
2881 -- For all other cases, just set the type of the Name
2883 else
2891 -- Move to next interpretation
2899 -- At this stage Found indicates whether or not an acceptable
2900 -- interpretation exists. If not, then we have an error, except that if
2901 -- the context is Any_Type as a result of some other error, then we
2902 -- suppress the error report.
2907 -- If type we are looking for is Void, then this is the procedure
2908 -- call case, and the error is simply that what we gave is not a
2909 -- procedure name (we think of procedure calls as expressions with
2910 -- types internally, but the user doesn't think of them this way).
2914 -- Special case message if function used as a procedure
2919 then
2920 Error_Msg_NE
2923 Error_Msg_N
2927 -- Otherwise give general message (not clear what cases this
2928 -- covers, but no harm in providing for them).
2930 else
2936 -- Otherwise we do have a subexpression with the wrong type
2938 -- Check for the case of an allocator which uses an access type
2939 -- instead of the designated type. This is a common error and we
2940 -- specialize the message, posting an error on the operand of the
2941 -- allocator, complaining that we expected the designated type of
2942 -- the allocator.
2948 then
2952 -- Check for view mismatch on Null in instances, for which the
2953 -- view-swapping mechanism has no identifier.
2959 then
2964 -- Check for an aggregate. Sometimes we can get bogus aggregates
2965 -- from misuse of parentheses, and we are about to complain about
2966 -- the aggregate without even looking inside it.
2968 -- Instead, if we have an aggregate of type Any_Composite, then
2969 -- analyze and resolve the component fields, and then only issue
2970 -- another message if we get no errors doing this (otherwise
2971 -- assume that the errors in the aggregate caused the problem).
2975 then
2978 then
2987 -- Disable expansion in any case. If there is a type mismatch
2988 -- it may be fatal to try to expand the aggregate. The flag
2989 -- would otherwise be set to false when the error is posted.
2993 declare
2995 -- Check one aggregate, and set Found to True if we have a
2996 -- definite error in any of its elements
2999 -- Check one element of aggregate and set Found to True if
3000 -- we definitely have an error in the element.
3002 ----------------
3003 -- Check_Aggr --
3004 ----------------
3009 begin
3022 -- If this is a default-initialized component, then
3023 -- there is nothing to check. The box will be
3024 -- replaced by the appropriate call during late
3025 -- expansion.
3029 then
3038 ----------------
3039 -- Check_Elmt --
3040 ----------------
3043 begin
3044 -- If we have a nested aggregate, go inside it (to
3045 -- attempt a naked analyze-resolve of the aggregate can
3046 -- cause undesirable cascaded errors). Do not resolve
3047 -- expression if it needs a type from context, as for
3048 -- integer * fixed expression.
3053 else
3058 then
3068 begin
3073 -- Check whether the node is a literal or a named number or a
3074 -- conditional expression whose dependent expressions are all
3075 -- literals or named numbers.
3081 -- Looks like we have a type error, but check for special case
3082 -- of Address wanted, integer found, with the configuration pragma
3083 -- Allow_Integer_Address active. If we have this case, introduce
3084 -- an unchecked conversion to allow the integer expression to be
3085 -- treated as an Address. The reverse case of integer wanted,
3086 -- Address found, is treated in an analogous manner.
3093 -- Under relaxed RM semantics silently replace occurrences of null
3094 -- by System.Null_Address.
3102 -- That special Allow_Integer_Address check did not apply, so we
3103 -- have a real type error. If an error message was issued already,
3104 -- Found got reset to True, so if it's still False, issue standard
3105 -- Wrong_Type message.
3109 declare
3112 begin
3118 -- Protected operation: retrieve operation name
3122 else
3127 Error_Msg_NE
3133 declare
3137 begin
3144 Error_Msg_NE
3150 else
3154 -- Recognize the case of a quantified expression being mistaken
3155 -- for an iterated component association because the user
3156 -- forgot the "all" or "some" keyword after "for". Because the
3157 -- error message starts with "missing ALL", we automatically
3158 -- benefit from the associated CODEFIX, which requires that
3159 -- the message is located on the identifier following "for"
3160 -- in order for the CODEFIX to insert "all" in the right place.
3165 = N_Iterated_Component_Association
3167 then
3168 if Present
3169 (Iterator_Specification
3171 then
3172 Error_Msg_N -- CODEFIX
3174 Defining_Identifier
3175 (Iterator_Specification
3177 else
3178 Error_Msg_N -- CODEFIX
3180 Defining_Identifier
3184 -- For an operator with no interpretation, check whether one of
3185 -- its operands may be a user-defined literal.
3190 else
3194 else
3200 Resolution_Failed;
3203 -- Test if we have more than one interpretation for the context
3206 Resolution_Failed;
3209 -- Only one interpretation
3211 else
3212 -- Prevent implicit conversions between access-to-subprogram types
3213 -- with different strub modes. Explicit conversions are acceptable in
3214 -- some circumstances. We don't have to be concerned about data or
3215 -- access-to-data types. Conversions between data types can safely
3216 -- drop or add strub attributes from types, because strub effects are
3217 -- associated with the locations rather than values. E.g., converting
3218 -- a hypothetical Strub_Integer variable to Integer would load the
3219 -- value from the variable, enabling stack scrabbing for the
3220 -- enclosing subprogram, and then convert the value to Integer. As
3221 -- for conversions between access-to-data types, that's no different
3222 -- from any other case of type punning.
3228 then
3229 Check_Same_Strub_Mode
3233 -- In Ada 2005, if we have something like "X : T := 2 + 2;", where
3234 -- the "+" on T is abstract, and the operands are of universal type,
3235 -- the above code will have (incorrectly) resolved the "+" to the
3236 -- universal one in Standard. Therefore check for this case and give
3237 -- an error. We can't do this earlier, because it would cause legal
3238 -- cases to get errors (when some other type has an abstract "+").
3244 then
3249 then
3250 Nondispatching_Call_To_Abstract_Operation
3259 -- Here we have an acceptable interpretation for the context
3261 -- Propagate type information and normalize tree for various
3262 -- predefined operations. If the context only imposes a class of
3263 -- types, rather than a specific type, propagate the actual type
3264 -- downward.
3270 Typ = Any_Discrete
3271 then
3274 -- Any_Fixed is legal in a real context only if a specific fixed-
3275 -- point type is imposed. If Norman Cohen can be confused by this,
3276 -- it deserves a separate message.
3280 then
3287 -- A user-defined operator is transformed into a function call at
3288 -- this point, so that further processing knows that operators are
3289 -- really operators (i.e. are predefined operators). User-defined
3290 -- operators that are intrinsic are just renamings of the predefined
3291 -- ones, and need not be turned into calls either, but if they rename
3292 -- a different operator, we must transform the node accordingly.
3293 -- Instantiations of Unchecked_Conversion are intrinsic but are
3294 -- treated as functions, even if given an operator designator.
3299 then
3304 and then
3306 N_Subprogram_Renaming_Declaration
3307 then
3310 -- If the node is rewritten, it will be fully resolved in
3311 -- Rewrite_Renamed_Operator.
3320 when N_Aggregate =>
3321 Resolve_Aggregate (N, Ctx_Type);
3323 when N_Allocator =>
3324 Resolve_Allocator (N, Ctx_Type);
3326 when N_Short_Circuit =>
3327 Resolve_Short_Circuit (N, Ctx_Type);
3329 when N_Attribute_Reference =>
3330 Resolve_Attribute (N, Ctx_Type);
3332 when N_Case_Expression =>
3333 Resolve_Case_Expression (N, Ctx_Type);
3335 when N_Character_Literal =>
3336 Resolve_Character_Literal (N, Ctx_Type);
3338 when N_Delta_Aggregate =>
3339 Resolve_Delta_Aggregate (N, Ctx_Type);
3341 when N_Expanded_Name =>
3342 Resolve_Entity_Name (N, Ctx_Type);
3344 when N_Explicit_Dereference =>
3345 Resolve_Explicit_Dereference (N, Ctx_Type);
3347 when N_Expression_With_Actions =>
3348 Resolve_Expression_With_Actions (N, Ctx_Type);
3350 when N_Extension_Aggregate =>
3351 Resolve_Extension_Aggregate (N, Ctx_Type);
3353 when N_Function_Call =>
3354 Resolve_Call (N, Ctx_Type);
3356 when N_Identifier =>
3357 Resolve_Entity_Name (N, Ctx_Type);
3359 when N_If_Expression =>
3360 Resolve_If_Expression (N, Ctx_Type);
3362 when N_Indexed_Component =>
3363 Resolve_Indexed_Component (N, Ctx_Type);
3365 when N_Integer_Literal =>
3366 Resolve_Integer_Literal (N, Ctx_Type);
3368 when N_Membership_Test =>
3369 Resolve_Membership_Op (N, Ctx_Type);
3371 when N_Null =>
3372 Resolve_Null (N, Ctx_Type);
3374 when N_Op_And
3375 | N_Op_Or
3376 | N_Op_Xor
3377 =>
3378 Resolve_Logical_Op (N, Ctx_Type);
3380 when N_Op_Eq
3381 | N_Op_Ne
3382 =>
3383 Resolve_Equality_Op (N, Ctx_Type);
3385 when N_Op_Ge
3386 | N_Op_Gt
3387 | N_Op_Le
3388 | N_Op_Lt
3389 =>
3390 Resolve_Comparison_Op (N, Ctx_Type);
3392 when N_Op_Not =>
3393 Resolve_Op_Not (N, Ctx_Type);
3395 when N_Op_Add
3396 | N_Op_Divide
3397 | N_Op_Mod
3398 | N_Op_Multiply
3399 | N_Op_Rem
3400 | N_Op_Subtract
3401 =>
3402 Resolve_Arithmetic_Op (N, Ctx_Type);
3404 when N_Op_Concat =>
3405 Resolve_Op_Concat (N, Ctx_Type);
3407 when N_Op_Expon =>
3408 Resolve_Op_Expon (N, Ctx_Type);
3410 when N_Op_Abs
3411 | N_Op_Minus
3412 | N_Op_Plus
3413 =>
3414 Resolve_Unary_Op (N, Ctx_Type);
3416 when N_Op_Shift =>
3417 Resolve_Shift (N, Ctx_Type);
3419 when N_Procedure_Call_Statement =>
3420 Resolve_Call (N, Ctx_Type);
3422 when N_Operator_Symbol =>
3423 Resolve_Operator_Symbol (N, Ctx_Type);
3425 when N_Qualified_Expression =>
3426 Resolve_Qualified_Expression (N, Ctx_Type);
3428 -- Why is the following null, needs a comment ???
3430 when N_Quantified_Expression =>
3431 null;
3433 when N_Raise_Expression =>
3434 Resolve_Raise_Expression (N, Ctx_Type);
3436 when N_Raise_xxx_Error =>
3437 Set_Etype (N, Ctx_Type);
3439 when N_Range =>
3440 Resolve_Range (N, Ctx_Type);
3442 when N_Real_Literal =>
3443 Resolve_Real_Literal (N, Ctx_Type);
3445 when N_Reference =>
3446 Resolve_Reference (N, Ctx_Type);
3448 when N_Selected_Component =>
3449 Resolve_Selected_Component (N, Ctx_Type);
3451 when N_Slice =>
3452 Resolve_Slice (N, Ctx_Type);
3454 when N_String_Literal =>
3455 Resolve_String_Literal (N, Ctx_Type);
3457 when N_Interpolated_String_Literal =>
3458 Resolve_Interpolated_String_Literal (N, Ctx_Type);
3460 when N_Target_Name =>
3461 Resolve_Target_Name (N, Ctx_Type);
3463 when N_Type_Conversion =>
3464 Resolve_Type_Conversion (N, Ctx_Type);
3466 when N_Unchecked_Expression =>
3467 Resolve_Unchecked_Expression (N, Ctx_Type);
3469 when N_Unchecked_Type_Conversion =>
3470 Resolve_Unchecked_Type_Conversion (N, Ctx_Type);
3471 end case;
3473 -- Mark relevant use-type and use-package clauses as effective using
3474 -- the original node because constant folding may have occurred and
3475 -- removed references that need to be examined.
3477 if Nkind (Original_Node (N)) in N_Op then
3478 Mark_Use_Clauses (Original_Node (N));
3479 end if;
3481 -- Ada 2012 (AI05-0149): Apply an (implicit) conversion to an
3482 -- expression of an anonymous access type that occurs in the context
3483 -- of a named general access type, except when the expression is that
3484 -- of a membership test. This ensures proper legality checking in
3485 -- terms of allowed conversions (expressions that would be illegal to
3486 -- convert implicitly are allowed in membership tests).
3488 if Ada_Version >= Ada_2012
3489 and then Ekind (Base_Type (Ctx_Type)) = E_General_Access_Type
3490 and then Ekind (Etype (N)) = E_Anonymous_Access_Type
3491 and then Nkind (Parent (N)) not in N_Membership_Test
3492 then
3493 Rewrite (N, Convert_To (Ctx_Type, Relocate_Node (N)));
3494 Analyze_And_Resolve (N, Ctx_Type);
3495 end if;
3497 -- If the subexpression was replaced by a non-subexpression, then
3498 -- all we do is to expand it. The only legitimate case we know of
3499 -- is converting procedure call statement to entry call statements,
3500 -- but there may be others, so we are making this test general.
3502 if Nkind (N) not in N_Subexpr then
3503 Debug_A_Exit ("resolving ", N, " (done)");
3504 Expand (N);
3505 return;
3506 end if;
3508 -- The expression is definitely NOT overloaded at this point, so
3509 -- we reset the Is_Overloaded flag to avoid any confusion when
3510 -- reanalyzing the node.
3512 Set_Is_Overloaded (N, False);
3514 -- Freeze expression type, entity if it is a name, and designated
3515 -- type if it is an allocator (RM 13.14(10,11,13)).
3517 -- Now that the resolution of the type of the node is complete, and
3518 -- we did not detect an error, we can expand this node. We skip the
3519 -- expand call if we are in a default expression, see section
3520 -- "Handling of Default Expressions" in Sem spec.
3522 Debug_A_Exit ("resolving ", N, " (done)");
3524 -- We unconditionally freeze the expression, even if we are in
3525 -- default expression mode (the Freeze_Expression routine tests this
3526 -- flag and only freezes static types if it is set).
3528 -- Ada 2012 (AI05-177): The declaration of an expression function
3529 -- does not cause freezing, but we never reach here in that case.
3530 -- Here we are resolving the corresponding expanded body, so we do
3531 -- need to perform normal freezing.
3533 -- As elsewhere we do not emit freeze node within a generic.
3535 if not Inside_A_Generic then
3536 Freeze_Expression (N);
3537 end if;
3539 -- Now we can do the expansion
3541 Expand (N);
3542 end if;
3543 end Resolve;
3545 -------------
3546 -- Resolve --
3547 -------------
3549 -- Version with check(s) suppressed
3551 procedure Resolve (N : Node_Id; Typ : Entity_Id; Suppress : Check_Id) is
3552 begin
3553 if Suppress = All_Checks then
3554 declare
3555 Sva : constant Suppress_Array := Scope_Suppress.Suppress;
3556 begin
3557 Scope_Suppress.Suppress := (others => True);
3558 Resolve (N, Typ);
3559 Scope_Suppress.Suppress := Sva;
3560 end;
3562 else
3563 declare
3564 Svg : constant Boolean := Scope_Suppress.Suppress (Suppress);
3565 begin
3566 Scope_Suppress.Suppress (Suppress) := True;
3567 Resolve (N, Typ);
3568 Scope_Suppress.Suppress (Suppress) := Svg;
3569 end;
3570 end if;
3571 end Resolve;
3573 -------------
3574 -- Resolve --
3575 -------------
3577 -- Version with implicit type
3579 procedure Resolve (N : Node_Id) is
3580 begin
3581 Resolve (N, Etype (N));
3582 end Resolve;
3584 ---------------------
3585 -- Resolve_Actuals --
3586 ---------------------
3588 procedure Resolve_Actuals (N : Node_Id; Nam : Entity_Id) is
3589 Loc : constant Source_Ptr := Sloc (N);
3590 A : Node_Id;
3591 A_Typ : Entity_Id := Empty; -- init to avoid warning
3592 F : Entity_Id;
3593 F_Typ : Entity_Id;
3594 Prev : Node_Id := Empty;
3595 Orig_A : Node_Id;
3596 Real_F : Entity_Id := Empty; -- init to avoid warning
3598 Real_Subp : Entity_Id;
3599 -- If the subprogram being called is an inherited operation for
3600 -- a formal derived type in an instance, Real_Subp is the subprogram
3601 -- that will be called. It may have different formal names than the
3602 -- operation of the formal in the generic, so after actual is resolved
3603 -- the name of the actual in a named association must carry the name
3604 -- of the actual of the subprogram being called.
3606 procedure Check_Aliased_Parameter;
3607 -- Check rules on aliased parameters and related accessibility rules
3608 -- in (RM 3.10.2 (10.2-10.4)).
3610 procedure Check_Argument_Order;
3611 -- Performs a check for the case where the actuals are all simple
3612 -- identifiers that correspond to the formal names, but in the wrong
3613 -- order, which is considered suspicious and cause for a warning.
3615 procedure Check_Prefixed_Call;
3616 -- If the original node is an overloaded call in prefix notation,
3618 -- Try_Object_Operation has already verified that there is a valid
3619 -- interpretation, but the form of the actual can only be determined
3620 -- once the primitive operation is identified.
3623 -- Emit an error concerning the illegal usage of an effectively volatile
3624 -- object for reading in interfering context (SPARK RM 7.1.3(10)).
3627 -- If the actual is missing in a call, insert in the actuals list
3628 -- an instance of the default expression. The insertion is always
3629 -- a named association.
3632 -- Check whether T1 and T2, or their full views, are derived from a
3633 -- common type. Used to enforce the restrictions on array conversions
3634 -- of AI95-00246.
3637 -- Predicate to determine whether an actual that is a concatenation
3638 -- will be evaluated statically and does not need a transient scope.
3639 -- This must be determined before the actual is resolved and expanded
3640 -- because if needed the transient scope must be introduced earlier.
3642 -----------------------------
3643 -- Check_Aliased_Parameter --
3644 -----------------------------
3649 begin
3657 else
3664 -- In a generic body assume the worst for generic formals:
3665 -- they can have a constrained partial view (AI05-041).
3669 and then not Object_Type_Has_Constrained_Partial_View
3671 then
3674 else
3679 else
3691 then
3699 then
3700 Error_Msg_N
3706 --------------------------
3707 -- Check_Argument_Order --
3708 --------------------------
3711 begin
3712 -- Nothing to do if no parameters, or original node is neither a
3713 -- function call nor a procedure call statement (happens in the
3714 -- operator-transformed-to-function call case), or the call is to an
3715 -- operator symbol (which is usually in infix form), or the call does
3716 -- not come from source, or this warning is off.
3718 if not Warn_On_Parameter_Order
3724 N_Defining_Operator_Symbol)
3726 then
3730 declare
3733 begin
3734 -- Nothing to do if only one parameter
3740 -- Here if at least two arguments
3742 declare
3748 -- Set True if an out of order case is found
3750 begin
3751 -- Collect identifier names of actuals, fail if any actual is
3752 -- not a simple identifier, and record max length of name.
3758 else
3764 -- If we got this far, all actuals are identifiers and the list
3765 -- of their names is stored in the Actuals array.
3770 -- If we ran out of formals, that's odd, probably an error
3771 -- which will be detected elsewhere, but abandon the search.
3777 -- If name matches and is in order OK
3782 else
3783 -- If no match, see if it is elsewhere in list and if so
3784 -- flag potential wrong order if type is compatible.
3788 and then
3790 then
3796 -- No match
3804 -- If Formals left over, also probably an error, skip warning
3810 -- Here we give the warning if something was out of order
3813 Error_Msg_N
3820 -------------------------
3821 -- Check_Prefixed_Call --
3822 -------------------------
3831 begin
3832 -- Check whether the call is a prefixed call, with or without
3833 -- additional actuals.
3836 or else
3842 then
3845 then
3846 -- Introduce dereference on object in prefix
3848 New_A :=
3856 then
3857 -- Introduce an implicit 'Access in prefix
3860 Error_Msg_NE
3876 ---------------------------------------
3877 -- Flag_Effectively_Volatile_Objects --
3878 ---------------------------------------
3882 -- Determine whether arbitrary node N denotes an effectively volatile
3883 -- object for reading and if it does, emit an error.
3885 -----------------
3886 -- Flag_Object --
3887 -----------------
3892 begin
3894 -- Do not consider nested function calls because they have
3895 -- already been processed during their own resolution.
3903 -- Identifiers of components and discriminants are not names
3904 -- in the sense of Ada RM 4.1. They can only occur as a
3905 -- selector_name in selected_component or as a choice in
3906 -- component_association.
3912 and then
3916 then
3918 Error_Msg_N
3920 N);
3932 -- Start of processing for Flag_Effectively_Volatile_Objects
3934 begin
3938 --------------------
3939 -- Insert_Default --
3940 --------------------
3946 begin
3947 -- Missing argument in call, nothing to insert
3952 else
3953 -- Note that we do a full New_Copy_Tree, so that any associated
3954 -- Itypes are properly copied. This may not be needed any more,
3955 -- but it does no harm as a safety measure. Defaults of a generic
3956 -- formal may be out of bounds of the corresponding actual (see
3957 -- cc1311b) and an additional check may be required.
3959 Actval :=
3960 New_Copy_Tree
3965 -- Propagate dimension information, if any.
3971 then
3977 then
3980 then
3981 -- If default is a real literal, do not introduce a
3982 -- conversion whose effect may depend on the run-time
3983 -- size of universal real.
3987 else
3998 -- Resolve aggregates with their base type, to avoid scope
3999 -- anomalies: the subtype was first built in the subprogram
4000 -- declaration, and the current call may be nested.
4004 else
4008 else
4011 -- See note above concerning aggregates
4015 then
4018 -- Resolve entities with their own type, which may differ from
4019 -- the type of a reference in a generic context (the view
4020 -- swapping mechanism did not anticipate the re-analysis of
4021 -- default values in calls).
4026 else
4031 -- If default is a tag indeterminate function call, propagate tag
4032 -- to obtain proper dispatching.
4036 then
4041 -- If the default expression raises constraint error, then just
4042 -- silently replace it with an N_Raise_Constraint_Error node, since
4043 -- we already gave the warning on the subprogram spec. If node is
4044 -- already a Raise_Constraint_Error leave as is, to prevent loops in
4045 -- the warnings removal machinery.
4049 then
4058 Assoc :=
4063 -- Case of insertion is first named actual
4067 then
4074 else
4078 else
4082 -- Case of insertion is not first named actual
4084 else
4085 Set_Next_Named_Actual
4097 -------------------
4098 -- Same_Ancestor --
4099 -------------------
4105 begin
4108 then
4114 then
4121 --------------------------
4122 -- Static_Concatenation --
4123 --------------------------
4126 begin
4133 -- Concatenation is static when both operands are static and
4134 -- the concatenation operator is a predefined one.
4137 and then
4139 and then
4144 declare
4146 begin
4149 and then
4153 else
4159 -- Start of processing for Resolve_Actuals
4161 begin
4162 Check_Argument_Order;
4166 and then In_Instance
4169 then
4171 else
4176 Check_Prefixed_Call;
4190 -- If we have an error in any formal or actual, indicated by a type
4191 -- of Any_Type, then abandon resolution attempt, and set result type
4192 -- to Any_Type.
4199 -- For the peculiar case of a user-defined comparison or equality
4200 -- operator that does not return a boolean type, the operands may
4201 -- have been ambiguous for the predefined operator and, therefore,
4202 -- marked with Any_Type. Since the operation has been resolved to
4203 -- the user-defined operator, that is irrelevant, so reset Etype.
4207 then
4210 -- Also skip this if the actual is a Raise_Expression, whose type
4211 -- is imposed from context.
4216 else
4222 -- Case where actual is present
4224 -- If the actual is an entity, generate a reference to it now. We
4225 -- do this before the actual is resolved, because a formal of some
4226 -- protected subprogram, or a task discriminant, will be rewritten
4227 -- during expansion, and the source entity reference may be lost.
4232 then
4233 -- Annotate the tree by creating a variable reference marker when
4234 -- the actual denotes a variable reference, in case the reference
4235 -- is folded or optimized away. The variable reference marker is
4236 -- automatically saved for later examination by the ABE Processing
4237 -- phase. The status of the reference is set as follows:
4239 -- status mode
4240 -- read IN, IN OUT
4241 -- write IN OUT, OUT
4243 if Needs_Variable_Reference_Marker
4246 then
4247 Build_Variable_Reference_Marker
4258 then
4265 -- RM 6.4.1(12): For an out parameter that is passed by
4266 -- copy, the formal parameter object is created, and:
4268 -- * For an access type, the formal parameter is initialized
4269 -- from the value of the actual, without checking that the
4270 -- value satisfies any constraint, any predicate, or any
4271 -- exclusion of the null value.
4273 -- * For a scalar type that has the Default_Value aspect
4274 -- specified, the formal parameter is initialized from the
4275 -- value of the actual, without checking that the value
4276 -- satisfies any constraint or any predicate.
4277 -- I do not understand why this case is included??? this is
4278 -- not a case where an OUT parameter is treated as IN OUT.
4280 -- * For a composite type with discriminants or that has
4281 -- implicit initial values for any subcomponents, the
4282 -- behavior is as for an in out parameter passed by copy.
4284 -- Hence for these cases we generate the read reference now
4285 -- (the write reference will be generated later by
4286 -- Note_Possible_Modification).
4289 and then
4291 or else
4293 and then
4295 or else
4298 or else Is_Partially_Initialized_Type
4300 then
4310 then
4311 -- If style checking mode on, check match of formal name
4319 -- If the formal is Out or In_Out, do not resolve and expand the
4320 -- conversion, because it is subsequently expanded into explicit
4321 -- temporaries and assignments. However, the object of the
4322 -- conversion can be resolved. An exception is the case of tagged
4323 -- type conversion with a class-wide actual. In that case we want
4324 -- the tag check to occur and no temporary will be needed (no
4325 -- representation change can occur) and the parameter is passed by
4326 -- reference, so we go ahead and resolve the type conversion.
4327 -- Another exception is the case of reference to component or
4328 -- subcomponent of a bit-packed array, in which case we want to
4329 -- defer expansion to the point the in and out assignments are
4330 -- performed.
4336 then
4337 declare
4340 begin
4341 -- Check RM 4.6 (24.2/2)
4345 then
4346 -- In a view conversion, the conversion must be legal in
4347 -- both directions, and thus both component types must be
4348 -- aliased, or neither (4.6 (8)).
4350 -- Check RM 4.6 (24.8/2)
4354 then
4355 -- This normally illegal conversion is legal in an
4356 -- expanded instance body because of RM 12.3(11).
4357 -- At runtime, conversion must create a new object.
4360 Error_Msg_N
4365 -- Check RM 4.6 (24/3)
4368 -- Check view conv between unrelated by ref array
4369 -- types.
4373 then
4374 Error_Msg_N
4378 -- In Ada 2005 mode, check view conversion component
4379 -- type cannot be private, tagged, or volatile. Note
4380 -- that we only apply this to source conversions. The
4381 -- generated code can contain conversions which are
4382 -- not subject to this test, and we cannot extract the
4383 -- component type in such cases since it is not
4384 -- present.
4388 then
4389 declare
4392 begin
4397 then
4398 Error_Msg_N
4408 -- AI12-0074 & AI12-0377
4409 -- Check 6.4.1: If the mode is out, the actual parameter is
4410 -- a view conversion, and the type of the formal parameter
4411 -- is a scalar type, then either:
4412 -- - the target and operand type both do not have the
4413 -- Default_Value aspect specified; or
4414 -- - the target and operand type both have the
4415 -- Default_Value aspect specified, and there shall exist
4416 -- a type (other than a root numeric type) that is an
4417 -- ancestor of both the target type and the operand
4418 -- type.
4422 then
4425 then
4426 Error_Msg_N
4431 then
4432 Error_Msg_N
4439 -- Resolve expression if conversion is all OK
4444 then
4448 -- If the actual is a function call that returns a limited
4449 -- unconstrained object that needs finalization, create a
4450 -- transient scope for it, so that it can receive the proper
4451 -- finalization list.
4453 elsif Expander_Active
4459 then
4463 -- A small optimization: if one of the actuals is a concatenation
4464 -- create a block around a procedure call to recover stack space.
4465 -- This alleviates stack usage when several procedure calls in
4466 -- the same statement list use concatenation. We do not perform
4467 -- this wrapping for code statements, where the argument is a
4468 -- static string, and we want to preserve warnings involving
4469 -- sequences of such statements.
4471 elsif Expander_Active
4477 then
4481 else
4485 and then
4488 then
4489 Error_Msg_N
4502 -- (Ada 2005: AI-251): If the actual is an allocator whose
4503 -- directly designated type is a class-wide interface, we build
4504 -- an anonymous access type to use it as the type of the
4505 -- allocator. Later, when the subprogram call is expanded, if
4506 -- the interface has a secondary dispatch table the expander
4507 -- will add a type conversion to force the correct displacement
4508 -- of the pointer.
4511 declare
4515 begin
4516 -- Displace the pointer to the object to reference its
4517 -- secondary dispatch table.
4521 then
4527 -- Ada 2005, AI-162:If the actual is an allocator, the
4528 -- innermost enclosing statement is the master of the
4529 -- created object. This needs to be done with expansion
4530 -- enabled only, otherwise the transient scope will not
4531 -- be removed in the expansion of the wrapped construct.
4533 if Expander_Active
4536 then
4537 Establish_Transient_Scope
4547 -- (Ada 2005): The call may be to a primitive operation of a
4548 -- tagged synchronized type, declared outside of the type. In
4549 -- this case the controlling actual must be converted to its
4550 -- corresponding record type, which is the formal type. The
4551 -- actual may be a subtype, either because of a constraint or
4552 -- because it is a generic actual, so use base type to locate
4553 -- concurrent type.
4560 then
4561 -- If the actual is overloaded, look for an interpretation
4562 -- that has a synchronized type.
4567 else
4568 declare
4572 begin
4577 then
4587 declare
4590 begin
4593 else
4597 -- Tagged synchronized type (case 1): the actual is a
4598 -- concurrent type.
4602 then
4604 Unchecked_Convert_To
4608 -- Tagged synchronized type (case 2): the formal is a
4609 -- concurrent type.
4612 and then Present
4617 then
4620 -- Common case
4622 else
4627 -- Not a synchronized operation
4629 else
4637 -- An actual cannot be an untagged formal incomplete type
4642 then
4643 Error_Msg_N
4647 -- For mode IN, if actual is an entity, and the type of the formal
4648 -- has warnings suppressed, then we reset Never_Set_In_Source for
4649 -- the calling entity. The reason for this is to catch cases like
4650 -- GNAT.Spitbol.Patterns.Vstring_Var where the called subprogram
4651 -- uses trickery to modify an IN parameter.
4658 then
4662 -- Perform error checks for IN and IN OUT parameters
4666 -- Check unset reference. For scalar parameters, it is clearly
4667 -- wrong to pass an uninitialized value as either an IN or
4668 -- IN-OUT parameter. For composites, it is also clearly an
4669 -- error to pass a completely uninitialized value as an IN
4670 -- parameter, but the case of IN OUT is trickier. We prefer
4671 -- not to give a warning here. For example, suppose there is
4672 -- a routine that sets some component of a record to False.
4673 -- It is perfectly reasonable to make this IN-OUT and allow
4674 -- either initialized or uninitialized records to be passed
4675 -- in this case.
4677 -- For partially initialized composite values, we also avoid
4678 -- warnings, since it is quite likely that we are passing a
4679 -- partially initialized value and only the initialized fields
4680 -- will in fact be read in the subprogram.
4685 then
4689 -- In Ada 83 we cannot pass an OUT parameter as an IN or IN OUT
4690 -- actual to a nested call, since this constitutes a reading of
4691 -- the parameter, which is not allowed.
4696 then
4701 -- In -gnatd.q mode, forget that a given array is constant when
4702 -- it is passed as an IN parameter to a foreign-convention
4703 -- subprogram. This is in case the subprogram evilly modifies the
4704 -- object. Of course, correct code would use IN OUT.
4706 if Debug_Flag_Dot_Q
4712 then
4716 -- Case of OUT or IN OUT parameter
4720 -- For an Out parameter, check for useless assignment. Note
4721 -- that we can't set Last_Assignment this early, because we may
4722 -- kill current values in Resolve_Call, and that call would
4723 -- clobber the Last_Assignment field.
4725 -- Note: call Warn_On_Useless_Assignment before doing the check
4726 -- below for Is_OK_Variable_For_Out_Formal so that the setting
4727 -- of Referenced_As_LHS/Referenced_As_Out_Formal properly
4728 -- reflects the last assignment, not this one.
4735 then
4740 -- Validate the form of the actual. Note that the call to
4741 -- Is_OK_Variable_For_Out_Formal generates the required
4742 -- reference in this case.
4744 -- A call to an initialization procedure for an aggregate
4745 -- component may initialize a nested component of a constant
4746 -- designated object. In this context the object is variable.
4750 then
4756 then
4757 Error_Msg_N
4762 Error_Msg_N
4769 -- What's the following about???
4773 else
4774 Kill_All_Checks;
4783 -- Apply appropriate constraint/predicate checks for IN [OUT] case
4787 -- Apply predicate tests except in certain special cases. Note
4788 -- that it might be more consistent to apply these only when
4789 -- expansion is active (in Exp_Ch6.Expand_Actuals), as we do
4790 -- for the outbound predicate tests ??? In any case indicate
4791 -- the function being called, for better warnings if the call
4792 -- leads to an infinite recursion.
4798 -- Apply required constraint checks
4811 then
4814 -- For view conversions of a discriminated object, apply
4815 -- check to object itself, the conversion alreay has the
4816 -- proper type.
4820 then
4827 then
4833 then
4836 else
4840 -- Ada 2005 (AI-231): Note that the controlling parameter case
4841 -- already existed in Ada 95, which is partially checked
4842 -- elsewhere (see Checks), and we don't want the warning
4843 -- message to differ.
4848 then
4850 Apply_Compile_Time_Constraint_Error
4856 Apply_Compile_Time_Constraint_Error
4865 -- Checks for OUT parameters and IN OUT parameters
4869 -- If there is a type conversion, make sure the return value
4870 -- meets the constraints of the variable before the conversion.
4875 -- Special case here tailored to Exp_Ch6.Is_Legal_Copy,
4876 -- which would prevent the check from being generated.
4877 -- This is for Starlet only though, so long obsolete.
4882 then
4884 else
4885 Apply_Scalar_Range_Check
4889 -- In addition the return value must meet the constraints
4890 -- of the object type (see the comment below).
4894 else
4895 Apply_Range_Check
4899 -- If no conversion, apply scalar range checks and length check
4900 -- based on the subtype of the actual (NOT that of the formal).
4901 -- This indicates that the check takes place on return from the
4902 -- call. During expansion the required constraint checks are
4903 -- inserted. In GNATprove mode, in the absence of expansion,
4904 -- the flag indicates that the returned value is valid.
4906 else
4912 then
4915 else
4920 -- Note: we do not apply the predicate checks for the case of
4921 -- OUT and IN OUT parameters. They are instead applied in the
4922 -- Expand_Actuals routine in Exp_Ch6.
4925 -- If the formal is of an unconstrained array subtype with fixed
4926 -- lower bound, then sliding to that bound may be needed.
4932 -- An actual associated with an access parameter is implicitly
4933 -- converted to the anonymous access type of the formal and must
4934 -- satisfy the legality checks for access conversions.
4938 Error_Msg_N
4942 -- If the actual is an access selected component of a variable,
4943 -- the call may modify its designated object. It is reasonable
4944 -- to treat this as a potential modification of the enclosing
4945 -- record, to prevent spurious warnings that it should be
4946 -- declared as a constant, because intuitively programmers
4947 -- regard the designated subcomponent as part of the record.
4952 then
4957 -- Check illegal cases of atomic/volatile/VFA actual (RM C.6(12))
4961 then
4964 then
4965 Error_Msg_NE
4968 Error_Msg_N
4973 then
4974 Error_Msg_NE
4977 Error_Msg_N
4982 then
4983 Error_Msg_NE
4986 Error_Msg_N
4990 -- Check for nonatomic subcomponent of a full access object
4991 -- in Ada 2022 (RM C.6 (12)).
4996 then
4997 Error_Msg_N
5000 Error_Msg_NE
5006 -- Check that subprograms don't have improper controlling
5007 -- arguments (RM 3.9.2 (9)).
5009 -- A primitive operation may have an access parameter of an
5010 -- incomplete tagged type, but a dispatching call is illegal
5011 -- if the type is still incomplete.
5017 declare
5019 begin
5023 then
5024 Error_Msg_NE
5035 -- Apply legality rule 3.9.2 (9/1)
5037 -- Skip this check on helpers and indirect-call wrappers built to
5038 -- support class-wide preconditions.
5043 and then not In_Instance
5046 then
5051 Error_Msg_NE
5055 -- Apply the checks described in 3.10.2(27): if the context is a
5056 -- specific access-to-object, the actual cannot be class-wide.
5057 -- Use base type to exclude access_to_subprogram cases.
5064 and then
5069 -- Disable these checks for call to imported C++ subprograms
5071 and then not
5075 then
5076 Error_Msg_N
5081 Error_Msg_NE
5086 Check_Aliased_Parameter;
5090 -- If it is a named association, treat the selector_name as a
5091 -- proper identifier, and mark the corresponding entity.
5095 -- Ignore reference in SPARK mode, as it refers to an entity not
5096 -- in scope at the point of reference, so the reference should
5097 -- be ignored for computing effects of subprograms.
5099 and then not GNATprove_Mode
5100 then
5101 -- If subprogram is overridden, use name of formal that
5102 -- is being called.
5108 else
5122 -- The following checks are only relevant when SPARK_Mode is on as
5123 -- they are not standard Ada legality rule. Internally generated
5124 -- temporaries are ignored.
5128 -- Inspect the expression and flag each effectively volatile
5129 -- object for reading as illegal because it appears within
5130 -- an interfering context. Note that this is usually done
5131 -- in Resolve_Entity_Name, but when the effectively volatile
5132 -- object for reading appears as an actual in a call, the call
5133 -- must be resolved first.
5138 -- A formal parameter of a specific tagged type whose related
5139 -- subprogram is subject to pragma Extensions_Visible with value
5140 -- "False" cannot act as an actual in a subprogram with value
5141 -- "True" (SPARK RM 6.1.7(3)).
5143 -- No check needed for helpers and indirect-call wrappers built to
5144 -- support class-wide preconditions.
5148 Extensions_Visible_True
5149 and then not
5151 and then
5153 then
5154 Error_Msg_N
5157 Error_Msg_NE
5161 -- The actual parameter of a Ghost subprogram whose formal is of
5162 -- mode IN OUT or OUT must be a Ghost variable (SPARK RM 6.9(12)).
5170 then
5171 Error_Msg_NE
5177 else
5182 -- (AI12-0397): The target of a subprogram call that occurs within
5183 -- the expression of an Default_Initial_Condition aspect and has
5184 -- an actual that is the current instance of the type must be
5185 -- either a primitive of the type or a class-wide subprogram,
5186 -- because the type of the current instance in such an aspect is
5187 -- considered to be a notional formal derived type whose only
5188 -- operations correspond to the primitives of the enclosing type.
5189 -- Nonprimitives can be called, but the current instance must be
5190 -- converted rather than passed directly. Note that a current
5191 -- instance of a type with DIC will occur as a reference to an
5192 -- in-mode formal of an enclosing DIC procedure or partial DIC
5193 -- procedure. (It seems that this check should perhaps also apply
5194 -- to calls within Type_Invariant'Class, but not Type_Invariant,
5195 -- aspects???)
5203 -- We check Comes_From_Source to exclude inherited primitives
5204 -- from being flagged, because such subprograms turn out to not
5205 -- always have the Is_Primitive flag set. ???
5211 then
5212 Error_Msg_NE
5219 -- Case where actual is not present
5221 else
5222 Insert_Default;
5233 -----------------------
5234 -- Resolve_Allocator --
5235 -----------------------
5247 procedure Check_Allocator_Discrim_Accessibility
5250 -- Check that accessibility level associated with an access discriminant
5251 -- initialized in an allocator by the expression Disc_Exp is not deeper
5252 -- than the level of the allocator type Alloc_Typ. An error message is
5253 -- issued if this condition is violated. Specialized checks are done for
5254 -- the cases of a constraint expression which is an access attribute or
5255 -- an access discriminant.
5257 procedure Check_Allocator_Discrim_Accessibility_Exprs
5260 -- Dispatch checks performed by Check_Allocator_Discrim_Accessibility
5261 -- across all expressions within a given conditional expression.
5264 -- If the allocator is an actual in a call, it is allowed to be class-
5265 -- wide when the context is not because it is a controlling actual.
5267 -------------------------------------------
5268 -- Check_Allocator_Discrim_Accessibility --
5269 -------------------------------------------
5271 procedure Check_Allocator_Discrim_Accessibility
5274 is
5275 begin
5278 then
5279 Error_Msg_N
5282 -- When the expression is an Access attribute the level of the prefix
5283 -- object must not be deeper than that of the allocator's type.
5287 Attribute_Access
5288 and then Static_Accessibility_Level
5291 then
5292 Error_Msg_N
5294 Disc_Exp);
5296 -- When the expression is an access discriminant the check is against
5297 -- the level of the prefix object.
5301 and then Static_Accessibility_Level
5304 then
5305 Error_Msg_N
5307 Disc_Exp);
5309 -- All other cases are legal
5311 else
5316 -------------------------------------------------
5317 -- Check_Allocator_Discrim_Accessibility_Exprs --
5318 -------------------------------------------------
5320 procedure Check_Allocator_Discrim_Accessibility_Exprs
5323 is
5327 begin
5328 -- When conditional expressions are constant folded we know at
5329 -- compile time which expression to check - so don't bother with
5330 -- the rest of the cases.
5335 -- Non-constant-folded if expressions
5338 -- Check both expressions if they are still present in the face
5339 -- of expansion.
5346 Check_Allocator_Discrim_Accessibility_Exprs
5351 -- Non-constant-folded case expressions
5354 -- Check all alternatives
5358 Check_Allocator_Discrim_Accessibility_Exprs
5364 -- Base case, check the accessibility of the original node of the
5365 -- expression.
5367 else
5372 ----------------------------
5373 -- In_Dispatching_Context --
5374 ----------------------------
5379 begin
5385 -- Start of processing for Resolve_Allocator
5387 begin
5388 -- Replace general access with specific type
5398 -- For qualified expression, resolve the expression using the given
5399 -- subtype (nothing to do for type mark, subtype indication)
5404 and then not In_Dispatching_Context
5405 then
5406 Error_Msg_N
5410 -- Do a full resolution to apply constraint and predicate checks
5415 -- Allocators generated by the build-in-place expansion mechanism
5416 -- are explicitly marked as coming from source but do not need to be
5417 -- checked for limited initialization. To exclude this case, ensure
5418 -- that the parent of the allocator is a source node.
5419 -- The return statement constructed for an Expression_Function does
5420 -- not come from source but requires a limited check.
5424 and then
5426 or else
5430 and then not In_Instance_Body
5431 then
5434 Error_Msg_N
5437 else
5438 Error_Msg_N
5446 -- Calls to build-in-place functions are not currently supported in
5447 -- allocators for access types associated with a simple storage pool.
5448 -- Supporting such allocators may require passing additional implicit
5449 -- parameters to build-in-place functions (or a significant revision
5450 -- of the current b-i-p implementation to unify the handling for
5451 -- multiple kinds of storage pools). ???
5455 then
5456 declare
5459 begin
5461 and then
5462 Present (Get_Rep_Pragma
5464 then
5465 Error_Msg_N
5472 -- A special accessibility check is needed for allocators that
5473 -- constrain access discriminants. The level of the type of the
5474 -- expression used to constrain an access discriminant cannot be
5475 -- deeper than the type of the allocator (in contrast to access
5476 -- parameters, where the level of the actual can be arbitrary).
5478 -- We can't use Valid_Conversion to perform this check because in
5479 -- general the type of the allocator is unrelated to the type of
5480 -- the access discriminant.
5484 then
5491 then
5494 -- Get the first component expression of the aggregate
5504 else
5508 else
5514 Check_Allocator_Discrim_Accessibility_Exprs
5528 else
5533 else
5542 -- For a subtype mark or subtype indication, freeze the subtype
5544 else
5548 Error_Msg_N
5552 -- A special accessibility check is needed for allocators that
5553 -- constrain access discriminants. The level of the type of the
5554 -- expression used to constrain an access discriminant cannot be
5555 -- deeper than the type of the allocator (in contrast to access
5556 -- parameters, where the level of the actual can be arbitrary).
5557 -- We can't use Valid_Conversion to perform this check because
5558 -- in general the type of the allocator is unrelated to the type
5559 -- of the access discriminant.
5564 then
5574 else
5578 Check_Allocator_Discrim_Accessibility_Exprs
5589 -- Ada 2005 (AI-344): A class-wide allocator requires an accessibility
5590 -- check that the level of the type of the created object is not deeper
5591 -- than the level of the allocator's access type, since extensions can
5592 -- now occur at deeper levels than their ancestor types. This is a
5593 -- static accessibility level check; a run-time check is also needed in
5594 -- the case of an initialized allocator with a class-wide argument (see
5595 -- Expand_Allocator_Expression).
5599 then
5600 declare
5603 begin
5608 else
5614 then
5617 Error_Msg_N
5627 -- Do not apply Ada 2005 accessibility checks on a class-wide
5628 -- allocator if the type given in the allocator is a formal
5629 -- type or within a formal package. A run-time check will be
5630 -- performed in the instance.
5634 then
5635 Error_Msg_N
5643 -- Check for allocation from an empty storage pool. But do not complain
5644 -- if it's a return statement for a build-in-place function, because the
5645 -- allocator is there just in case the caller uses an allocator. If the
5646 -- caller does use an allocator, it will be caught at the call site.
5650 then
5653 -- If the context is an unchecked conversion, as may happen within an
5654 -- inlined subprogram, the allocator is being resolved with its own
5655 -- anonymous type. In that case, if the target type has a specific
5656 -- storage pool, it must be inherited explicitly by the allocator type.
5660 then
5661 Set_Associated_Storage_Pool
5669 -- Check that an allocator with task parts isn't for a nested access
5670 -- type when restriction No_Task_Hierarchy applies.
5674 then
5678 -- An illegal allocator may be rewritten as a raise Program_Error
5679 -- statement.
5683 -- Avoid coextension processing for an allocator that is the
5684 -- expansion of a build-in-place function call.
5688 N_Qualified_Expression
5690 N_Function_Call
5691 and then Is_Expanded_Build_In_Place_Call
5693 then
5696 else
5697 -- An anonymous access discriminant is the definition of a
5698 -- coextension.
5702 N_Discriminant_Specification
5703 then
5704 declare
5708 begin
5711 -- Ada 2012 AI05-0052: If the designated type of the
5712 -- allocator is limited, then the allocator shall not
5713 -- be used to define the value of an access discriminant
5714 -- unless the discriminated type is immutably limited.
5719 then
5720 Error_Msg_N
5723 N);
5727 -- Avoid marking an allocator as a dynamic coextension if it is
5728 -- within a static construct.
5733 -- Finalization and deallocation of coextensions utilizes an
5734 -- approximate implementation which does not directly adhere
5735 -- to the semantic rules. Warn on potential issues involving
5736 -- coextensions.
5739 Error_Msg_N
5742 else
5743 Error_Msg_N
5749 -- Cleanup for potential static coextensions
5751 else
5755 -- Anonymous access-to-controlled objects are not finalized on
5756 -- time because this involves run-time ownership and currently
5757 -- this property is not available. In rare cases the object may
5758 -- not be finalized at all. Warn on potential issues involving
5759 -- anonymous access-to-controlled objects.
5763 then
5764 Error_Msg_N
5774 -- Report a simple error: if the designated object is a local task,
5775 -- its body has not been seen yet, and its activation will fail an
5776 -- elaboration check.
5783 then
5789 -- Ada 2012 (AI05-0111-3): Detect an attempt to allocate a task or a
5790 -- type with a task component on a subpool. This action must raise
5791 -- Program_Error at runtime.
5797 then
5809 ---------------------------
5810 -- Resolve_Arithmetic_Op --
5811 ---------------------------
5813 -- Used for resolving all arithmetic operators except exponentiation
5824 -- We do the resolution using the base type, because intermediate values
5825 -- in expressions always are of the base type, not a subtype of it.
5828 -- Returns True if N is in a context that expects "any real type"
5831 -- Return True iff given type is Integer or universal real/integer
5834 -- Choose type of integer literal in fixed-point operation to conform
5835 -- to available fixed-point type. T is the type of the other operand,
5836 -- which is needed to determine the expected type of N.
5839 -- Set operand type to T if universal
5841 -------------------------------
5842 -- Expected_Type_Is_Any_Real --
5843 -------------------------------
5846 begin
5847 -- N is the expression after "delta" in a fixed_point_definition;
5848 -- see RM-3.5.9(6):
5851 | N_Decimal_Fixed_Point_Definition
5853 -- N is one of the bounds in a real_range_specification;
5854 -- see RM-3.5.7(5):
5856 | N_Real_Range_Specification
5858 -- N is the expression of a delta_constraint;
5859 -- see RM-J.3(3):
5861 | N_Delta_Constraint;
5864 -----------------------------
5865 -- Is_Integer_Or_Universal --
5866 -----------------------------
5873 begin
5878 else
5883 then
5894 ----------------------------
5895 -- Set_Mixed_Mode_Operand --
5896 ----------------------------
5902 begin
5905 -- A universal integer literal is resolved as standard integer
5906 -- except in the case of a fixed-point result, where we leave it
5907 -- as universal (to be handled by Exp_Fixd later on)
5911 else
5918 then
5919 -- A universal real can appear in a fixed-type context. We resolve
5920 -- the literal with that context, even though this might raise an
5921 -- exception prematurely (the other operand may be zero).
5928 then
5929 -- Integer arg in mixed-mode operation. Resolve with universal
5930 -- type, in case preference rule must be applied.
5936 -- If the operand is part of a fixed multiplication operation,
5937 -- a conversion will be applied to each operand, so resolve it
5938 -- with its own type.
5943 else
5944 -- Not a mixed-mode operation, resolve with context
5951 -- N may itself be a mixed-mode operation, so use context type
5958 then
5959 -- Must be (fixed * fixed) operation, operand must have one
5960 -- compatible interpretation.
5967 then
5968 -- C * F(X) in a fixed context, where C is a real literal or a
5969 -- fixed-point expression. F must have either a fixed type
5970 -- interpretation or an integer interpretation, but not both.
5977 else
5984 else
5992 -- Reanalyze the literal with the fixed type of the context. If
5993 -- context is Universal_Fixed, we are within a conversion, leave
5994 -- the literal as a universal real because there is no usable
5995 -- fixed type, and the target of the conversion plays no role in
5996 -- the resolution.
5998 declare
6002 begin
6005 else
6011 then
6013 else
6021 -- A universal real conditional expression can appear in a fixed-type
6022 -- context and must be resolved with that context to facilitate the
6023 -- code generation in the back end. However, If the context is
6024 -- Universal_fixed (i.e. as an operand of a multiplication/division
6025 -- involving a fixed-point operand) the conditional expression must
6026 -- resolve to a unique visible fixed_point type, normally Duration.
6031 then
6035 else
6039 else
6044 ----------------------
6045 -- Set_Operand_Type --
6046 ----------------------
6049 begin
6055 -- Start of processing for Resolve_Arithmetic_Op
6057 begin
6061 then
6066 -- Special-case for mixed-mode universal expressions or fixed point type
6067 -- operation: each argument is resolved separately. The same treatment
6068 -- is required if one of the operands of a fixed point operation is
6069 -- universal real, since in this case we don't do a conversion to a
6070 -- specific fixed-point type (instead the expander handles the case).
6072 -- Set the type of the node to its universal interpretation because
6073 -- legality checks on an exponentiation operand need the context.
6078 then
6089 or else
6092 then
6097 -- If context is a fixed type and one operand is integer, the other
6098 -- is resolved with the type of the context.
6103 then
6110 then
6114 -- If both operands are universal and the context is a floating
6115 -- point type, the operands are resolved to the type of the context.
6121 else
6126 -- Check the rule in RM05-4.5.5(19.1/2) disallowing universal_fixed
6127 -- multiplying operators from being used when the expected type is
6128 -- also universal_fixed. Note that B_Typ will be Universal_Fixed in
6129 -- some cases where the expected type is actually Any_Real;
6130 -- Expected_Type_Is_Any_Real takes care of that case.
6134 then
6138 N_Type_Conversion | N_Unchecked_Type_Conversion
6139 then
6146 else
6150 N_Type_Conversion | N_Unchecked_Type_Conversion
6151 then
6152 Error_Msg_N
6157 -- The expected type is "any real type" in contexts like
6159 -- type T is delta <universal_fixed-expression> ...
6161 -- in which case we need to set the type to Universal_Real
6162 -- so that static expression evaluation will work properly.
6166 else
6176 then
6181 -- If no previous errors, this is only possible if one operand is
6182 -- overloaded and the context is universal. Resolve as such.
6187 else
6189 and then
6191 then
6195 -- If the context is Universal_Fixed and the operands are also
6196 -- universal fixed, this is an error, unless there is only one
6197 -- applicable fixed_point type (usually Duration).
6205 else
6210 else
6215 -- If one of the arguments was resolved to a non-universal type.
6216 -- label the result of the operation itself with the same type.
6217 -- Do the same for the universal argument, if any.
6229 -- Set overflow and division checking bit
6236 -- Give warning if explicit division by zero
6240 then
6246 or else
6249 then
6250 -- Specialize the warning message according to the operation.
6251 -- When SPARK_Mode is On, force a warning instead of an error
6252 -- in that case, as this likely corresponds to deactivated
6253 -- code. The following warnings are for the case
6258 -- For division, we have two cases, for float division
6259 -- of an unconstrained float type, on a machine where
6260 -- Machine_Overflows is false, we don't get an exception
6261 -- at run-time, but rather an infinity or Nan. The Nan
6262 -- case is pretty obscure, so just warn about infinities.
6266 and then not Machine_Overflows_On_Target
6267 then
6268 Error_Msg_N
6272 -- For all other cases, we get a Constraint_Error
6274 else
6275 Apply_Compile_Time_Constraint_Error
6282 Apply_Compile_Time_Constraint_Error
6288 Apply_Compile_Time_Constraint_Error
6293 -- Division by zero can only happen with division, rem,
6294 -- and mod operations.
6300 -- Otherwise just set the flag to check at run time
6302 else
6307 -- If Restriction No_Implicit_Conditionals is active, then it is
6308 -- violated if either operand can be negative for mod, or for rem
6309 -- if both operands can be negative.
6313 then
6314 declare
6321 -- Set if corresponding operand might be negative
6323 begin
6324 Determine_Range
6328 Determine_Range
6332 -- Check if we will be generating conditionals. There are two
6333 -- cases where that can happen, first for REM, the only case
6334 -- is largest negative integer mod -1, where the division can
6335 -- overflow, but we still have to give the right result. The
6336 -- front end generates a test for this annoying case. Here we
6337 -- just test if both operands can be negative (that's what the
6338 -- expander does, so we match its logic here).
6340 -- The second case is mod where either operand can be negative.
6341 -- In this case, the back end has to generate additional tests.
6344 or else
6346 then
6357 ------------------
6358 -- Resolve_Call --
6359 ------------------
6374 begin
6375 -- Preserve relevant elaboration-related attributes of the context which
6376 -- are no longer available or very expensive to recompute once analysis,
6377 -- resolution, and expansion are over.
6379 Mark_Elaboration_Attributes
6385 -- The context imposes a unique interpretation with type Typ on a
6386 -- procedure or function call. Find the entity of the subprogram that
6387 -- yields the expected type, and propagate the corresponding formal
6388 -- constraints on the actuals. The caller has established that an
6389 -- interpretation exists, and emitted an error if not unique.
6391 -- First deal with the case of a call to an access-to-subprogram,
6392 -- dereference made explicit in Analyze_Call.
6398 else
6399 -- Find the interpretation whose type (a subprogram type) has a
6400 -- return type that is compatible with the context. Analysis of
6401 -- the node has established that one exists.
6420 -- If the prefix is not an entity, then resolve it
6426 -- For an indirect call, we always invalidate checks, since we do not
6427 -- know whether the subprogram is local or global. Yes we could do
6428 -- better here, e.g. by knowing that there are no local subprograms,
6429 -- but it does not seem worth the effort. Similarly, we kill all
6430 -- knowledge of current constant values.
6432 Kill_Current_Values;
6434 -- If this is a procedure call which is really an entry call, do
6435 -- the conversion of the procedure call to an entry call. Protected
6436 -- operations use the same circuitry because the name in the call
6437 -- can be an arbitrary expression with special resolution rules.
6441 then
6448 -- Annotate the tree by creating a call marker in case the original
6449 -- call is transformed by expansion. The call marker is automatically
6450 -- saved for later examination by the ABE Processing phase.
6454 -- Kill checks and constant values, as above for indirect case
6455 -- Who knows what happens when another task is activated?
6457 Kill_Current_Values;
6460 -- Normal subprogram call with name established in Resolve
6466 -- Otherwise we must have the case of an overloaded call
6468 else
6471 -- Initialize Nam to prevent warning (we know it will be assigned
6472 -- in the loop below, but the compiler does not know that).
6488 -- Check that a call to Current_Task does not occur in an entry body
6491 declare
6494 begin
6496 loop
6499 -- Exclude calls that occur within the default of a formal
6500 -- parameter of the entry, since those are evaluated outside
6501 -- of the body.
6508 then
6511 Error_Msg_NE
6525 -- Check that a procedure call does not occur in the context of the
6526 -- entry call statement of a conditional or timed entry call. Note that
6527 -- the case of a call to a subprogram renaming of an entry will also be
6528 -- rejected. The test for N not being an N_Entry_Call_Statement is
6529 -- defensive, covering the possibility that the processing of entry
6530 -- calls might reach this point due to later modifications of the code
6531 -- above.
6536 then
6540 -- Ada 2005 (AI-345): If a procedure_call_statement is used
6541 -- for a procedure_or_entry_call, the procedure_name or
6542 -- procedure_prefix of the procedure_call_statement shall denote
6543 -- an entry renamed by a procedure, or (a view of) a primitive
6544 -- subprogram of a limited interface whose first parameter is
6545 -- a controlling parameter.
6550 then
6551 Error_Msg_N
6556 -- Check that this is not a call to a protected procedure or entry from
6557 -- within a protected function.
6561 -- Freeze the subprogram name if not in a spec-expression. Note that
6562 -- we freeze procedure calls as well as function calls. Procedure calls
6563 -- are not frozen according to the rules (RM 13.14(14)) because it is
6564 -- impossible to have a procedure call to a non-frozen procedure in
6565 -- pure Ada, but in the code that we generate in the expander, this
6566 -- rule needs extending because we can generate procedure calls that
6567 -- need freezing.
6569 -- In Ada 2012, expression functions may be called within pre/post
6570 -- conditions of subsequent functions or expression functions. Such
6571 -- calls do not freeze when they appear within generated bodies,
6572 -- (including the body of another expression function) which would
6573 -- place the freeze node in the wrong scope. An expression function
6574 -- is frozen in the usual fashion, by the appearance of a real body,
6575 -- or at the end of a declarative part. However an implicit call to
6576 -- an expression function may appear when it is part of a default
6577 -- expression in a call to an initialization procedure, and must be
6578 -- frozen now, even if the body is inserted at a later point.
6579 -- Otherwise, the call freezes the expression if expander is active,
6580 -- for example as part of an object declaration.
6583 and then not In_Spec_Expression
6585 and then
6588 then
6591 -- Force freeze of expression function in call
6600 -- For a predefined operator, the type of the result is the type imposed
6601 -- by context, except for a predefined operation on universal fixed.
6602 -- Otherwise the type of the call is the type returned by the subprogram
6603 -- being called.
6610 -- If the subprogram returns an array type, and the context requires the
6611 -- component type of that array type, the node is really an indexing of
6612 -- the parameterless call. Resolve as such. A pathological case occurs
6613 -- when the type of the component is an access to the array type. In
6614 -- this case the call is truly ambiguous. If the call is to an intrinsic
6615 -- subprogram, it can't be an indexed component. This check is necessary
6616 -- because if it's Unchecked_Conversion, and we have "type T_Ptr is
6617 -- access T;" and "type T is array (...) of T_Ptr;" (i.e. an array of
6618 -- pointers to the same array), the compiler gets confused and does an
6619 -- infinite recursion.
6622 and then
6625 or else
6628 and then
6631 then
6632 declare
6637 begin
6638 -- If this is a parameterless call there is no ambiguity and the
6639 -- call has the type of the function.
6648 -- Annotate the tree by creating a call marker in case the
6649 -- original call is transformed by expansion. The call marker
6650 -- is automatically saved for later examination by the ABE
6651 -- Processing phase.
6658 then
6659 Error_Msg_N
6661 else
6664 -- The called entity may be an explicit dereference, in which
6665 -- case there is no entity to set.
6673 or else
6675 and then
6677 then
6680 -- Indexed call to a parameterless function
6682 Index_Node :=
6684 Prefix =>
6687 else
6688 -- An Ada 2005 prefixed call to a primitive operation
6689 -- whose first parameter is the prefix. This prefix was
6690 -- prepended to the parameter list, which is actually a
6691 -- list of indexes. Remove the prefix in order to build
6692 -- the proper indexed component.
6694 Index_Node :=
6696 Prefix =>
6699 Parameter_Associations =>
6700 New_List
6705 -- Preserve the parenthesis count of the node
6709 -- Since we are correcting a node classification error made
6710 -- by the parser, we call Replace rather than Rewrite.
6721 -- Annotate the tree by creating a call marker in case
6722 -- the original call is transformed by expansion. The call
6723 -- marker is automatically saved for later examination by
6724 -- the ABE Processing phase.
6735 else
6736 -- If the called function is not declared in the main unit and it
6737 -- returns the limited view of type then use the available view (as
6738 -- is done in Try_Object_Operation) to prevent back-end confusion;
6739 -- for the function entity itself. The call must appear in a context
6740 -- where the nonlimited view is available. If the function entity is
6741 -- in the extended main unit then no action is needed, because the
6742 -- back end handles this case. In either case the type of the call
6743 -- is the nonlimited view.
6747 then
6754 else
6759 -- In the case where the call is to an overloaded subprogram, Analyze
6760 -- calls Normalize_Actuals once per overloaded subprogram. Therefore in
6761 -- such a case Normalize_Actuals needs to be called once more to order
6762 -- the actuals correctly. Otherwise the call will have the ordering
6763 -- given by the last overloaded subprogram whether this is the correct
6764 -- one being called or not.
6771 -- In any case, call is fully resolved now. Reset Overload flag, to
6772 -- prevent subsequent overload resolution if node is analyzed again
6777 -- A Ghost entity must appear in a specific context
6783 -- If we are calling the current subprogram from immediately within its
6784 -- body, then that is the case where we can sometimes detect cases of
6785 -- infinite recursion statically. Do not try this in case restriction
6786 -- No_Recursion is in effect anyway, and do it only for source calls.
6791 -- Issue warning for possible infinite recursion in the absence
6792 -- of the No_Recursion restriction.
6798 then
6799 -- Here we detected and flagged an infinite recursion, so we do
6800 -- not need to test the case below for further warnings. Also we
6801 -- are all done if we now have a raise SE node.
6807 -- If call is to immediately containing subprogram, then check for
6808 -- the case of a possible run-time detectable infinite recursion.
6810 else
6814 -- Ada 2022 (AI12-0075): Static functions are never allowed
6815 -- to make a recursive call, as specified by 6.8(5.4/5).
6818 Error_Msg_N
6827 -- Although in general case, recursion is not statically
6828 -- checkable, the case of calling an immediately containing
6829 -- subprogram is easy to catch.
6835 -- If the recursive call is to a parameterless subprogram,
6836 -- then even if we can't statically detect infinite
6837 -- recursion, this is pretty suspicious, and we output a
6838 -- warning. Furthermore, we will try later to detect some
6839 -- cases here at run time by expanding checking code (see
6840 -- Detect_Infinite_Recursion in package Exp_Ch6).
6842 -- If the recursive call is within a handler, do not emit a
6843 -- warning, because this is a common idiom: loop until input
6844 -- is correct, catch illegal input in handler and restart.
6850 then
6851 -- For the case of a procedure call. We give the message
6852 -- only if the call is the first statement in a sequence
6853 -- of statements, or if all previous statements are
6854 -- simple assignments. This is simply a heuristic to
6855 -- decrease false positives, without losing too many good
6856 -- warnings. The idea is that these previous statements
6857 -- may affect global variables the procedure depends on.
6858 -- We also exclude raise statements, that may arise from
6859 -- constraint checks and are probably unrelated to the
6860 -- intended control flow.
6864 then
6865 declare
6867 begin
6871 | N_Raise_Constraint_Error
6872 then
6881 -- Do not give warning if we are in a conditional context
6883 declare
6885 begin
6891 then
6896 -- Here warning is to be issued
6912 -- Check obsolescent reference to Ada.Characters.Handling subprogram
6916 -- If subprogram name is a predefined operator, it was given in
6917 -- functional notation. Replace call node with operator node, so
6918 -- that actuals can be resolved appropriately.
6930 -- Create a transient scope if the expander is active and the resulting
6931 -- type requires it.
6933 -- There are several notable exceptions:
6935 -- a) Intrinsic subprograms (Unchecked_Conversion and source info
6936 -- functions) do not use the secondary stack even though the return
6937 -- type may be unconstrained.
6939 -- b) Subprograms that are ignored ghost entities do not return anything
6941 -- c) Calls to a build-in-place function, since such functions may
6942 -- allocate their result directly in a target object, and cases where
6943 -- the result does get allocated in the secondary stack are checked for
6944 -- within the specialized Exp_Ch6 procedures for expanding those
6945 -- build-in-place calls.
6947 -- d) Calls to inlinable expression functions do not use the secondary
6948 -- stack (since the call will be replaced by its returned object).
6950 -- e) If the subprogram is marked Inline, then even if it returns
6951 -- an unconstrained type the call does not require use of the secondary
6952 -- stack. However, inlining will only take place if the body to inline
6953 -- is already present. It may not be available if e.g. the subprogram is
6954 -- declared in a child instance.
6956 -- f) If the subprogram is a static expression function and the call is
6957 -- a static call (the actuals are all static expressions), then we never
6958 -- want to create a transient scope (this could occur in the case of a
6959 -- static string-returning call).
6961 -- g) If the call is the expression of a simple return statement that
6962 -- returns on the same stack, since it will be handled as a tail call
6963 -- by Expand_Simple_Function_Return.
6965 if Expander_Active
6975 N_Subprogram_Declaration
6976 and then
6980 and then
6981 Needs_Secondary_Stack
6982 (Etype
6983 (Return_Applies_To
6986 then
6989 -- If the call appears within the bounds of a loop, it will be
6990 -- rewritten and reanalyzed, nothing left to do here.
6997 -- A protected function cannot be called within the definition of the
6998 -- enclosing protected type, unless it is part of a pre/postcondition
6999 -- on another protected operation. This may appear in the entry wrapper
7000 -- created for an entry with preconditions.
7005 and then not In_Spec_Expression
7007 then
7008 Error_Msg_NE
7012 -- Propagate interpretation to actuals, and add default expressions
7013 -- where needed.
7018 -- Overloaded literals are rewritten as function calls, for purpose of
7019 -- resolution. After resolution, we can replace the call with the
7020 -- literal itself.
7026 -- Avoid validation, since it is a static function call
7032 -- If the subprogram is not global, then kill all saved values and
7033 -- checks. This is a bit conservative, since in many cases we could do
7034 -- better, but it is not worth the effort. Similarly, we kill constant
7035 -- values. However we do not need to do this for internal entities
7036 -- (unless they are inherited user-defined subprograms), since they
7037 -- are not in the business of molesting local values.
7039 -- If the flag Suppress_Value_Tracking_On_Calls is set, then we also
7040 -- kill all checks and values for calls to global subprograms. This
7041 -- takes care of the case where an access to a local subprogram is
7042 -- taken, and could be passed directly or indirectly and then called
7043 -- from almost any context.
7045 -- Note: we do not do this step till after resolving the actuals. That
7046 -- way we still take advantage of the current value information while
7047 -- scanning the actuals.
7049 -- We suppress killing values if we are processing the nodes associated
7050 -- with N_Freeze_Entity nodes. Otherwise the declaration of a tagged
7051 -- type kills all the values as part of analyzing the code that
7052 -- initializes the dispatch tables.
7056 or else Suppress_Value_Tracking_On_Call
7061 then
7062 Kill_Current_Values;
7065 -- If we are warning about unread OUT parameters, this is the place to
7066 -- set Last_Assignment for OUT and IN OUT parameters. We have to do this
7067 -- after the above call to Kill_Current_Values (since that call clears
7068 -- the Last_Assignment field of all local variables).
7073 then
7074 declare
7078 begin
7088 then
7098 -- If the subprogram is a primitive operation, check whether or not
7099 -- it is a correct dispatching call.
7104 -- If the subprogram is an abstract operation, then flag an error
7110 -- If this is a dispatching call, generate the appropriate reference,
7111 -- for better source navigation in GNAT Studio.
7116 -- Normal case, not a dispatching call: generate a call reference
7118 else
7126 -- Check for violation of restriction No_Specific_Termination_Handlers
7127 -- and warn on a potentially blocking call to Abort_Task.
7131 or else
7133 then
7140 -- A call to Ada.Real_Time.Timing_Events.Set_Handler to set a relative
7141 -- timing event violates restriction No_Relative_Delay (AI-0211). We
7142 -- need to check the second argument to determine whether it is an
7143 -- absolute or relative timing event.
7148 then
7152 -- Issue an error for a call to an eliminated subprogram. This routine
7153 -- will not perform the check if the call appears within a default
7154 -- expression.
7158 -- Implement rule in 12.5.1 (23.3/2): In an instance, if the actual is
7159 -- class-wide and the call dispatches on result in a context that does
7160 -- not provide a tag, the call raises Program_Error.
7163 and then In_Instance
7168 then
7169 -- Verify that none of the formals are controlling
7171 declare
7175 begin
7197 -- Check for calling a function with OUT or IN OUT parameter when the
7198 -- calling context (us right now) is not Ada 2012, so does not allow
7199 -- OUT or IN OUT parameters in function calls. Functions declared in
7200 -- a predefined unit are OK, as they may be called indirectly from a
7201 -- user-declared instantiation.
7207 then
7212 -- Check the dimensions of the actuals in the call. For function calls,
7213 -- propagate the dimensions from the returned type to N.
7217 -- Check unreachable code after calls to procedures with No_Return
7223 -- All done, evaluate call and deal with elaboration issues
7231 -- Annotate the tree by creating a call marker in case the original call
7232 -- is transformed by expansion. The call marker is automatically saved
7233 -- for later examination by the ABE Processing phase.
7241 -- Ada 2022 (AI12-0075): If the call is a static call to a static
7242 -- expression function, then we want to "inline" the call, replacing
7243 -- it with the folded static result. This is not done if the checking
7244 -- for a potentially static expression is enabled or if an error has
7245 -- been posted on the call (which may be due to the check for recursive
7246 -- calls, in which case we don't want to fall into infinite recursion
7247 -- when doing the inlining).
7249 if not Checking_Potentially_Static_Expression
7253 then
7256 -- In GNATprove mode, expansion is disabled, but we want to inline some
7257 -- subprograms to facilitate formal verification. Indirect calls through
7258 -- a subprogram type or within a generic cannot be inlined. Inlining is
7259 -- performed only for calls subject to SPARK_Mode on.
7261 elsif GNATprove_Mode
7264 and then not Inside_A_Generic
7265 then
7272 -- Nothing to do if the subprogram is not eligible for inlining in
7273 -- GNATprove mode, or inlining is disabled with switch -gnatdm
7277 or else Debug_Flag_M
7278 then
7281 -- Calls cannot be inlined inside assertions, as GNATprove treats
7282 -- assertions as logic expressions. Only issue a message when the
7283 -- body has been seen, otherwise this leads to spurious messages
7284 -- on expression functions.
7287 Cannot_Inline
7291 -- Calls cannot be inlined inside default expressions
7294 Cannot_Inline
7297 -- Calls cannot be inlined inside potentially unevaluated
7298 -- expressions, as this would create complex actions inside
7299 -- expressions, that are not handled by GNATprove.
7302 Cannot_Inline
7306 -- Calls are not inlined inside the loop_parameter_specification
7307 -- or iterator_specification of the quantified expression, as they
7308 -- are only preanalyzed. Calls in the predicate part are handled
7309 -- by the previous test on potentially unevaluated expressions.
7312 Cannot_Inline
7315 -- Inlining should not be performed during preanalysis
7319 -- Do not inline calls inside expression functions or functions
7320 -- generated by the front end for subtype predicates, as this
7321 -- would prevent interpreting them as logical formulas in
7322 -- GNATprove. Only issue a message when the body has been seen,
7323 -- otherwise this leads to spurious messages on callees that
7324 -- are themselves expression functions.
7327 and then
7332 then
7333 declare
7337 begin
7339 Cannot_Inline
7344 Cannot_Inline
7349 Cannot_Inline
7353 else
7354 Cannot_Inline
7360 -- Cannot inline a call inside the definition of a record type,
7361 -- typically inside the constraints of the type. Calls in
7362 -- default expressions are also not inlined, but this is
7363 -- filtered out above when testing In_Default_Expr.
7366 Cannot_Inline
7369 -- With the one-pass inlining technique, a call cannot be
7370 -- inlined if the corresponding body has not been seen yet.
7373 Cannot_Inline
7376 -- Nothing to do if there is no body to inline, indicating that
7377 -- the subprogram is not suitable for inlining in GNATprove
7378 -- mode.
7383 -- Calls cannot be inlined inside the conditions of while
7384 -- loops, as this would create complex actions inside
7385 -- the condition, that are not handled by GNATprove.
7388 Cannot_Inline
7391 -- Do not inline calls which would possibly lead to missing a
7392 -- type conversion check on an input parameter.
7395 Cannot_Inline
7399 -- Otherwise, inline the call, issuing an info message when
7400 -- -gnatd_f is set.
7402 else
7404 Error_Msg_NE
7415 -----------------------------
7416 -- Resolve_Case_Expression --
7417 -----------------------------
7425 begin
7439 -- When the expression is of a scalar subtype different from the
7440 -- result subtype, then insert a conversion to ensure the generation
7441 -- of a constraint check.
7451 -- Apply RM 4.5.7 (17/3): whether the expression is statically or
7452 -- dynamically tagged must be known statically.
7460 Error_Msg_N
7474 -------------------------------
7475 -- Resolve_Character_Literal --
7476 -------------------------------
7482 begin
7483 -- Verify that the character does belong to the type of the context
7488 -- Wide_Wide_Character literals must always be defined, since the set
7489 -- of wide wide character literals is complete, i.e. if a character
7490 -- literal is accepted by the parser, then it is OK for wide wide
7491 -- character (out of range character literals are rejected).
7496 -- Always accept character literal for type Any_Character, which
7497 -- occurs in error situations and in comparisons of literals, both
7498 -- of which should accept all literals.
7503 -- For Standard.Character or a type derived from it, check that the
7504 -- literal is in range.
7511 -- For Standard.Wide_Character or a type derived from it, check that the
7512 -- literal is in range.
7519 -- If the entity is already set, this has already been resolved in a
7520 -- generic context, or comes from expansion. Nothing else to do.
7525 -- Otherwise we have a user defined character type, and we can use the
7526 -- standard visibility mechanisms to locate the referenced entity.
7528 else
7541 -- If we fall through, then the literal does not match any of the
7542 -- entries of the enumeration type. This isn't just a constraint error
7543 -- situation, it is an illegality (see RM 4.2).
7545 Error_Msg_NE
7549 ---------------------------
7550 -- Resolve_Comparison_Op --
7551 ---------------------------
7553 -- The operands must have compatible types and the boolean context does not
7554 -- participate in the resolution. The first pass verifies that the operands
7555 -- are not ambiguous and sets their type correctly, or to Any_Type in case
7556 -- of ambiguity. If both operands are strings or aggregates, then they are
7557 -- ambiguous even if they carry a single (universal) type.
7565 begin
7574 -- Deal with explicit ambiguity of operands
7583 -- Deal with other error cases
7587 T = Any_Character
7588 then
7591 else
7599 -- Resolve the operands if types OK
7608 -- Check comparison on unordered enumeration
7612 Error_Msg_NE
7622 --------------------------------
7623 -- Resolve_Declare_Expression --
7624 --------------------------------
7626 procedure Resolve_Declare_Expression
7629 is
7636 -- Use a tree traversal to replace each occurrence of the name of
7637 -- a local object declared in the construct, with the corresponding
7638 -- entity. This replaces the usual way to perform name capture by
7639 -- visibility, because it is not possible to place on the scope
7640 -- stack the fake scope created for the analysis of the local
7641 -- declarations; such a scope conflicts with the transient scopes
7642 -- that may be generated if the expression includes function calls
7643 -- requiring finalization.
7645 -------------------
7646 -- Replace_Local --
7647 -------------------
7650 begin
7651 -- The identifier may be the prefix of a selected component,
7652 -- but not a selector name, because the local entities do not
7653 -- have a scope that can be named: a selected component whose
7654 -- selector is a homonym of a local entity must denote some
7655 -- global entity.
7660 and then
7663 then
7673 -- Start of processing for Resolve_Declare_Expression
7675 begin
7681 N_Object_Declaration | N_Object_Renaming_Declaration
7683 then
7687 -- Traverse the expression to replace references to local
7688 -- variables that occur within declarations of the
7689 -- declare_expression.
7691 declare
7693 begin
7704 -- The end of the declarative list is a freeze point for the
7705 -- local declarations.
7716 -----------------------------------
7717 -- Resolve_Dependent_Expression --
7718 -----------------------------------
7720 procedure Resolve_Dependent_Expression
7724 is
7725 begin
7726 -- RM 4.5.7(8/3) says that the expected type of dependent expressions is
7727 -- that of the conditional expression but RM 4.5.7(10/3) forces the type
7728 -- of the conditional expression without changing the expected type (the
7729 -- expected type of the operand of a type conversion is any type), so we
7730 -- may have a gap between these two types that is bridged by the dynamic
7731 -- semantics specified by RM 4.5.7(20/3) with the associated legality
7732 -- rule RM 4.5.7(16/3) that will be automatically enforced.
7736 then
7739 else
7744 -----------------------------------------
7745 -- Resolve_Discrete_Subtype_Indication --
7746 -----------------------------------------
7748 procedure Resolve_Discrete_Subtype_Indication
7751 is
7755 begin
7763 else
7773 Error_Msg_NE
7776 -- Rewrite the constraint as a range of Typ
7777 -- to allow compilation to proceed further.
7789 else
7793 -- Additionally, we must check that the bounds are compatible
7794 -- with the given subtype, which might be different from the
7795 -- type of the context.
7799 -- ??? If the above check statically detects a Constraint_Error
7800 -- it replaces the offending bound(s) of the range R with a
7801 -- Constraint_Error node. When the itype which uses these bounds
7802 -- is frozen the resulting call to Duplicate_Subexpr generates
7803 -- a new temporary for the bounds.
7805 -- Unfortunately there are other itypes that are also made depend
7806 -- on these bounds, so when Duplicate_Subexpr is called they get
7807 -- a forward reference to the newly created temporaries and Gigi
7808 -- aborts on such forward references. This is probably sign of a
7809 -- more fundamental problem somewhere else in either the order of
7810 -- itype freezing or the way certain itypes are constructed.
7812 -- To get around this problem we call Remove_Side_Effects right
7813 -- away if either bounds of R are a Constraint_Error.
7815 declare
7819 begin
7835 -------------------------
7836 -- Resolve_Entity_Name --
7837 -------------------------
7839 -- Used to resolve identifiers and expanded names
7842 function Is_Assignment_Or_Object_Expression
7845 -- Determine whether node Context denotes an assignment statement or an
7846 -- object declaration whose expression is node Expr.
7849 -- Determine whether Expr is part of an N_Attribute_Reference
7850 -- expression.
7853 -- Determine whether Expr is in attribute Old
7855 function Within_Exceptional_Cases_Consequence
7858 -- Determine whether Expr is part of an Exceptional_Cases consequence
7860 ----------------------------------------
7861 -- Is_Assignment_Or_Object_Expression --
7862 ----------------------------------------
7864 function Is_Assignment_Or_Object_Expression
7867 is
7868 begin
7871 then
7874 -- Check whether a construct that yields a name is the expression of
7875 -- an assignment statement or an object declaration.
7878 | N_Explicit_Dereference
7879 | N_Indexed_Component
7880 | N_Selected_Component
7881 | N_Slice
7883 or else
7885 | N_Unchecked_Type_Conversion
7887 then
7888 return
7889 Is_Assignment_Or_Object_Expression
7893 -- Otherwise the context is not an assignment statement or an object
7894 -- declaration.
7896 else
7901 ----------------------
7902 -- In_Attribute_Old --
7903 ----------------------
7907 begin
7911 then
7914 -- Prevent the search from going too far
7926 -----------------------------
7927 -- Is_Attribute_Expression --
7928 -----------------------------
7932 begin
7937 -- Prevent the search from going too far
7949 ------------------------------------------
7950 -- Within_Exceptional_Cases_Consequence --
7951 ------------------------------------------
7953 function Within_Exceptional_Cases_Consequence
7956 is
7958 begin
7962 -- In Exceptional_Cases references to formal parameters are
7963 -- only allowed within consequences, so it is enough to
7964 -- recognize the pragma itself.
7970 -- Prevent the search from going too far
7982 -- Local variables
7987 -- Start of processing for Resolve_Entity_Name
7989 begin
7990 -- If garbage from errors, set to Any_Type and return
7997 -- Replace named numbers by corresponding literals. Note that this is
7998 -- the one case where Resolve_Entity_Name must reset the Etype, since
7999 -- it is currently marked as universal.
8009 -- For enumeration literals, we need to make sure that a proper style
8010 -- check is done, since such literals are overloaded, and thus we did
8011 -- not do a style check during the first phase of analysis.
8017 -- Case of (sub)type name appearing in a context where an expression
8018 -- is expected. This is legal if occurrence is a current instance.
8019 -- See RM 8.6 (17/3). It is also legal if the expression is
8020 -- part of a choice pattern for a case stmt/expr having a
8021 -- non-discrete selecting expression.
8027 -- Any other use is an error
8029 else
8030 Error_Msg_N
8034 -- Check discriminant use if entity is discriminant in current scope,
8035 -- i.e. discriminant of record or concurrent type currently being
8036 -- analyzed. Uses in corresponding body are unrestricted.
8041 then
8044 -- A parameterless generic function cannot appear in a context that
8045 -- requires resolution.
8050 -- In Ada 83 an OUT parameter cannot be read, but attributes of
8051 -- array types (i.e. bounds and length) are legal.
8059 or else Is_Assignment_Or_Object_Expression
8062 then
8067 -- In all other cases, just do the possible static evaluation
8069 else
8070 -- A deferred constant that appears in an expression must have a
8071 -- completion, unless it has been removed by in-place expansion of
8072 -- an aggregate. A constant that is a renaming does not need
8073 -- initialization.
8079 and then not In_Spec_Expression
8082 then
8086 then
8088 else
8089 Error_Msg_N
8099 -- When the entity appears in a parameter association, retrieve the
8100 -- related subprogram call.
8108 -- The following checks are only relevant when SPARK_Mode is On as
8109 -- they are not standard Ada legality rules.
8113 -- An effectively volatile object for reading must appear in
8114 -- non-interfering context (SPARK RM 7.1.3(10)).
8118 and then
8120 then
8122 SPARK_Msg_N
8126 -- Parameters of modes OUT or IN OUT of the subprogram shall not
8127 -- occur in the consequences of an exceptional contract unless
8128 -- they are either passed by reference or occur in the prefix
8129 -- of a reference to the 'Old attribute. For convenience, we also
8130 -- allow them as prefixes of attributes that do not actually read
8131 -- data from the object.
8138 and then
8140 | Name_First
8141 | Name_Last
8142 | Name_Length
8143 | Name_Range)
8146 then
8148 Error_Msg_N
8151 else
8152 Error_Msg_N
8156 Error_Msg_N
8160 -- Check for possible elaboration issues with respect to reads of
8161 -- variables. The act of renaming the variable is not considered a
8162 -- read as it simply establishes an alias.
8164 if Legacy_Elaboration_Checks
8166 and then Dynamic_Elaboration_Checks
8168 then
8173 -- The variable may eventually become a constituent of a single
8174 -- protected/task type. Record the reference now and verify its
8175 -- legality when analyzing the contract of the variable
8176 -- (SPARK RM 9.3).
8182 -- A Ghost entity must appear in a specific context
8188 -- We may be resolving an entity within expanded code, so a reference
8189 -- to an entity should be ignored when calculating effective use
8190 -- clauses to avoid inappropriate marking.
8196 -------------------
8197 -- Resolve_Entry --
8198 -------------------
8210 -- If the bounds of the entry family being called depend on task
8211 -- discriminants, build a new index subtype where a discriminant is
8212 -- replaced with the value of the discriminant of the target task.
8213 -- The target task is the prefix of the entry name in the call.
8215 -----------------------
8216 -- Actual_Index_Type --
8217 -----------------------
8227 -- If the bound is given by a discriminant, replace with a reference
8228 -- to the discriminant of the same name in the target task. If the
8229 -- entry name is the target of a requeue statement and the entry is
8230 -- in the current protected object, the bound to be used is the
8231 -- discriminal of the object (see Apply_Range_Check for details of
8232 -- the transformation).
8234 -----------------------------
8235 -- Actual_Discriminant_Ref --
8236 -----------------------------
8242 begin
8247 then
8253 then
8254 -- Note: here Bound denotes a discriminant of the corresponding
8255 -- record type tskV, whose discriminal is a formal of the
8256 -- init-proc tskVIP. What we want is the body discriminal,
8257 -- which is associated to the discriminant of the original
8258 -- concurrent type tsk.
8260 return New_Occurrence_Of
8263 else
8264 Ref :=
8274 -- Start of processing for Actual_Index_Type
8276 begin
8279 then
8282 else
8296 -- Start of processing for Resolve_Entry
8298 begin
8299 -- Find name of entry being called, and resolve prefix of name with its
8300 -- own type. The prefix can be overloaded, and the name and signature of
8301 -- the entry must be taken into account.
8305 -- Case of dealing with entry family within the current tasks
8309 else
8315 -- Entry call to an entry (or entry family) in the current task. This
8316 -- is legal even though the task will deadlock. Rewrite as call to
8317 -- current task.
8319 -- This can also be a call to an entry in an enclosing task. If this
8320 -- is a single task, we have to retrieve its name, because the scope
8321 -- of the entry is the task type, not the object. If the enclosing
8322 -- task is a task type, the identity of the task is given by its own
8323 -- self variable.
8325 -- Finally this can be a requeue on an entry of the same task or
8326 -- protected object.
8333 then
8334 -- S is an enclosing task or protected object. The concurrent
8335 -- declaration has been converted into a type declaration, and
8336 -- the object itself has an object declaration that follows
8337 -- the type in the same declarative part.
8349 -- Call to current task. Will be transformed into call to Self
8356 New_N :=
8359 Selector_Name =>
8366 then
8367 -- Use the entry name (which must be unique at this point) to find
8368 -- the prefix that returns the corresponding task/protected type.
8370 declare
8376 begin
8398 -- We do not resolve the prefix because an Entry_Family has no type,
8399 -- although it has the semantics of an array since it can be indexed.
8400 -- In order to perform the associated range check, we would need to
8401 -- build an array type on the fly and set it on the prefix, but this
8402 -- would be wasteful since only the index type matters. Therefore we
8403 -- attach this index type directly, so that Actual_Index_Expression
8404 -- can pick it up later in order to generate the range check.
8411 -- Generate a reference for the index when it denotes an entity
8417 -- Up to this point the expression could have been the actual in a
8418 -- simple entry call, and be given by a named association.
8422 else
8428 ------------------------
8429 -- Resolve_Entry_Call --
8430 ------------------------
8441 begin
8442 -- We kill all checks here, because it does not seem worth the effort to
8443 -- do anything better, an entry call is a big operation.
8445 Kill_All_Checks;
8447 -- Processing of the name is similar for entry calls and protected
8448 -- operation calls. Once the entity is determined, we can complete
8449 -- the resolution of the actuals.
8451 -- The selector may be overloaded, in the case of a protected object
8452 -- with overloaded functions. The type of the context is used for
8453 -- resolution.
8458 then
8459 declare
8463 begin
8482 -- Simple entry or protected operation call
8495 -- Call to member of entry family
8502 -- We cannot in general check the maximum depth of protected entry calls
8503 -- at compile time. But we can tell that any protected entry call at all
8504 -- violates a specified nesting depth of zero.
8510 -- Use context type to disambiguate a protected function that can be
8511 -- called without actuals and that returns an array type, and where the
8512 -- argument list may be an indexing of the returned value.
8517 and then
8523 and then
8524 Covers
8527 then
8528 declare
8531 begin
8532 Index_Node :=
8534 Prefix =>
8538 -- Since we are correcting a node classification error made by the
8539 -- parser, we call Replace rather than Rewrite.
8553 then
8554 -- Note the entity being called before rewriting the call, so that
8555 -- it appears used at this point.
8559 -- Rewrite as call to the precondition wrapper, adding the task
8560 -- object to the list of actuals. If the call is to a member of an
8561 -- entry family, include the index as well.
8563 declare
8567 begin
8576 New_Call :=
8578 Name =>
8583 -- Preanalyze and resolve new call. Current procedure is called
8584 -- from Resolve_Call, after which expansion will take place.
8591 -- The operation name may have been overloaded. Order the actuals
8592 -- according to the formals of the resolved entity, and set the return
8593 -- type to that of the operation.
8600 -- Reset the Is_Overloaded flag, since resolution is now completed
8602 -- Simple entry call
8607 -- Call to a member of an entry family
8617 -- Create a call reference to the entry
8625 -- Verify that a procedure call cannot masquerade as an entry
8626 -- call where an entry call is expected.
8631 then
8636 then
8641 then
8646 -- After resolution, entry calls and protected procedure calls are
8647 -- changed into entry calls, for expansion. The structure of the node
8648 -- does not change, so it can safely be done in place. Protected
8649 -- function calls must keep their structure because they are
8650 -- subexpressions.
8654 -- A protected operation that is not a function may modify the
8655 -- corresponding object, and cannot apply to a constant. If this
8656 -- is an internal call, the prefix is the type itself.
8662 then
8663 Error_Msg_N
8665 Entry_Name);
8668 declare
8671 begin
8672 Entry_Call :=
8677 -- Inherit relevant attributes from the original call
8679 Set_First_Named_Actual
8682 Set_Is_Elaboration_Checks_OK_Node
8685 Set_Is_Elaboration_Warnings_OK_Node
8688 Set_Is_SPARK_Mode_On_Node
8695 -- Protected functions can return on the secondary stack, in which case
8696 -- we must trigger the transient scope mechanism.
8698 elsif Expander_Active
8700 then
8704 -- Now we know that this is not a call to a function that returns an
8705 -- array type; moreover, we know the name of the called entry. Detect
8706 -- overlapping actuals, just like for a subprogram call.
8711 -------------------------
8712 -- Resolve_Equality_Op --
8713 -------------------------
8715 -- The operands must have compatible types and the boolean context does not
8716 -- participate in the resolution. The first pass verifies that the operands
8717 -- are not ambiguous and sets their type correctly, or to Any_Type in case
8718 -- of ambiguity. If both operands are strings, aggregates, allocators, or
8719 -- null, they are ambiguous even if they carry a single (universal) type.
8729 and then not
8731 -- Whether this is a call to the implicit inequality operator created
8732 -- for a user-defined operator that is not an intrinsic subprogram, in
8733 -- which case we need to skip some processing.
8738 -- For any object, '[Unchecked_]Access of such object can never be
8739 -- passed as an operand to the Universal_Access equality operators.
8740 -- This is so because the expected type for Obj'Access in a call to
8741 -- these operators, whose formals are of type Universal_Access, is
8742 -- Universal_Access, and Universal_Access does not have a designated
8743 -- type. For more details, see RM 3.10.2(2/2) and 6.4.1(3).
8746 -- Check RM 4.5.2(9.6/2) on the given designated object types
8749 -- Check RM 4.5.2(9.7/2) on the given designated subprogram types
8752 -- The resolution rule for if expressions requires that each such must
8753 -- have a unique type. This means that if several dependent expressions
8754 -- are of a non-null anonymous access type, and the context does not
8755 -- impose an expected type (as can be the case in an equality operation)
8756 -- the expression must be rejected.
8759 -- Attempt to explain the nature of a redundant comparison with True. If
8760 -- the expression N is too complex, this routine issues a general error
8761 -- message.
8764 -- In the case of allocators and access attributes, the context must
8765 -- provide an indication of the specific access type to be used. If
8766 -- one operand is of such a "generic" access type, check whether there
8767 -- is a specific visible access type that has the same designated type.
8768 -- This is semantically dubious, and of no interest to any real code,
8769 -- but c48008a makes it all worthwhile.
8772 -- Returns True iff the parent node is a and/or/xor operation that
8773 -- could be the cause of confused priorities. Note that if the not is
8774 -- in parens, then False is returned.
8776 ----------------------------
8777 -- Check_Access_Attribute --
8778 ----------------------------
8781 begin
8784 then
8785 Error_Msg_N
8791 -----------------------------------
8792 -- Check_Designated_Object_Types --
8793 -----------------------------------
8796 begin
8800 then
8801 Error_Msg_N
8809 ---------------------------------------
8810 -- Check_Designated_Subprogram_Types --
8811 ---------------------------------------
8814 begin
8816 Error_Msg_N
8824 -------------------------
8825 -- Check_If_Expression --
8826 -------------------------
8832 begin
8839 then
8845 ------------------------
8846 -- Explain_Redundancy --
8847 ------------------------
8854 begin
8857 -- Strip the operand down to an entity
8859 loop
8862 else
8867 -- The construct denotes an entity
8872 -- Do not generate an error message when the comparison is done
8873 -- against the enumeration literal Standard.True.
8877 -- Build a customized error message
8904 -- The construct is too complex to disect, issue a general message
8906 else
8911 -----------------------------
8912 -- Find_Unique_Access_Type --
8913 -----------------------------
8920 begin
8922 then
8926 then
8928 else
8940 then
8953 ----------------------------------
8954 -- Suspicious_Prio_For_Equality --
8955 ----------------------------------
8960 begin
8961 -- Check if parent node is one of and/or/xor, not parenthesized
8962 -- explicitly, and its own parent is not of this kind. Otherwise,
8963 -- it's a case of chained Boolean conditions which is likely well
8964 -- parenthesized.
8969 then
8970 declare
8974 else
8976 begin
8977 -- Compar may have been rewritten, for example from (a /= b)
8978 -- into not (a = b). Use the Original_Node instead.
8982 -- If the other argument of the and/or/xor is also a
8983 -- comparison, or another and/or/xor then most likely
8984 -- the priorities are correctly set.
8989 else
8994 -- Start of processing for Resolve_Equality_Op
8996 begin
9005 -- Deal with explicit ambiguity of operands, unless this is a call
9006 -- to the implicit inequality operator created for a user-defined
9007 -- operator that is not an intrinsic subprogram, since the common
9008 -- resolution of operands done here does not apply to it.
9010 if not Implicit_NE_For_User_Defined_Operator
9012 then
9016 else
9018 -- For Ada 2022, check for user-defined literals when the type has
9019 -- the appropriate aspect.
9031 -- Deal with other error cases
9035 T = Any_Character
9036 then
9039 else
9048 then
9057 -- If expressions must have a single type, and if the context does
9058 -- not impose one the dependent expressions cannot be anonymous
9059 -- access types.
9061 -- Why no similar processing for case expressions???
9066 then
9071 -- RM 4.5.2(9.5/2): At least one of the operands of the equality
9072 -- operators for universal_access shall be of type universal_access,
9073 -- or both shall be of access-to-object types, or both shall be of
9074 -- access-to-subprogram types (RM 4.5.2(9.5/2)).
9079 then
9080 -- RM 4.5.2(9.6/2): When both are of access-to-object types, the
9081 -- designated types shall be the same or one shall cover the other
9082 -- and if the designated types are elementary or array types, then
9083 -- the designated subtypes shall statically match.
9087 then
9088 Check_Designated_Object_Types
9091 -- RM 4.5.2(9.7/2): When both are of access-to-subprogram types,
9092 -- the designated profiles shall be subtype conformant.
9096 then
9097 Check_Designated_Subprogram_Types
9102 -- Check another case of equality operators for universal_access
9112 -- AI12-0413: user-defined primitive equality of an untagged record
9113 -- type hides the predefined equality operator, including within a
9114 -- generic, and if it is declared abstract, results in an illegal
9115 -- instance if the operator is used in the spec, or in the raising
9116 -- of Program_Error if used in the body of an instance.
9119 and then In_Instance
9121 then
9122 declare
9127 begin
9131 then
9137 else
9147 -- If the unique type is a class-wide type then it will be expanded
9148 -- into a dispatching call to the predefined primitive. Therefore we
9149 -- check here for potential violation of such restriction.
9155 -- Only warn for redundant equality comparison to True for objects
9156 -- (e.g. "X = True") and operations (e.g. "(X < Y) = True"). For
9157 -- other expressions, it may be a matter of preference to write
9158 -- "Expr = True" or "Expr".
9160 if Warn_On_Redundant_Constructs
9165 and then
9167 or else
9169 then
9170 Error_Msg_N -- CODEFIX
9175 -- Warn on a (in)equality between boolean values which is not
9176 -- parenthesized when the parent expression is one of and/or/xor, as
9177 -- this is interpreted as (a = b) op c where most likely a = (b op c)
9178 -- was intended. Do not generate a warning in generic instances, as
9179 -- the problematic expression may be implicitly parenthesized in
9180 -- the generic itself if one of the operators is a generic formal.
9181 -- Also do not generate a warning for generated equality, for
9182 -- example from rewritting a membership test.
9184 if Warn_On_Questionable_Missing_Parens
9185 and then not In_Instance
9188 and then Suspicious_Prio_For_Equality
9189 then
9198 -- Unless this is a call to the implicit inequality operator created
9199 -- for a user-defined operator that is not an intrinsic subprogram,
9200 -- try to fold the operation.
9208 then
9214 ----------------------------------
9215 -- Resolve_Explicit_Dereference --
9216 ----------------------------------
9224 -- The candidate prefix type, if overloaded
9229 begin
9233 -- A useful optimization: check whether the dereference denotes an
9234 -- element of a container, and if so rewrite it as a call to the
9235 -- corresponding Element function.
9237 -- Disabled for now, on advice of ARG. A more restricted form of the
9238 -- predicate might be acceptable ???
9240 -- if Is_Container_Element (N) then
9241 -- return;
9242 -- end if;
9246 -- Use the context type to select the prefix that has the correct
9247 -- designated type. Keep the first match, which will be the inner-
9248 -- most.
9255 then
9260 -- Remove access types that do not match, but preserve access
9261 -- to subprogram interpretations, in case a further dereference
9262 -- is needed (see below).
9275 else
9276 -- If no interpretation covers the designated type of the prefix,
9277 -- this is the pathological case where not all implementations of
9278 -- the prefix allow the interpretation of the node as a call. Now
9279 -- that the expected type is known, Remove other interpretations
9280 -- from prefix, rewrite it as a call, and resolve again, so that
9281 -- the proper call node is generated.
9292 New_N :=
9294 Name =>
9305 -- If not overloaded, resolve P with its own type
9307 else
9311 -- If the prefix might be null, add an access check
9315 then
9319 -- If the designated type is a packed unconstrained array type, and the
9320 -- explicit dereference is not in the context of an attribute reference,
9321 -- then we must compute and set the actual subtype, since it is needed
9322 -- by Gigi. The reason we exclude the attribute case is that this is
9323 -- handled fine by Gigi, and in fact we use such attributes to build the
9324 -- actual subtype. We also exclude generated code (which builds actual
9325 -- subtypes directly if they are needed).
9331 then
9337 -- Note: No Eval processing is required for an explicit dereference,
9338 -- because such a name can never be static.
9342 -------------------------------------
9343 -- Resolve_Expression_With_Actions --
9344 -------------------------------------
9349 -- True if Act is an action of a declare_expression that is allowed in a
9350 -- static declare_expression.
9353 -- True if all actions of N are allowed in a static declare_expression.
9356 -- Expr is an expression with compile-time-known value. This returns the
9357 -- literal node that reprsents that value.
9359 -------------------
9360 -- OK_For_Static --
9361 -------------------
9364 begin
9369 then
9379 -- No other declarations, nor even pragmas, are allowed in a
9380 -- declare expression, so if we see something else, it must be
9381 -- an internally generated expression_with_actions.
9388 -----------------------
9389 -- All_OK_For_Static --
9390 -----------------------
9394 begin
9406 -----------------
9407 -- Get_Literal --
9408 -----------------
9413 begin
9418 else
9427 pragma Assert
9433 -- Local variables
9437 -- Start of processing for Resolve_Expression_With_Actions
9439 begin
9446 -- If the value of the expression is known at compile time, and all
9447 -- of the actions (if any) are suitable, then replace the declare
9448 -- expression with its expression. This allows the declare expression
9449 -- as a whole to be static if appropriate. See AI12-0368.
9455 Rewrite
9462 ----------------------------------
9463 -- Resolve_Generalized_Indexing --
9464 ----------------------------------
9468 begin
9473 ---------------------------
9474 -- Resolve_If_Expression --
9475 ---------------------------
9481 -- When a dependent expression is of a subtype different from
9482 -- the context subtype, then insert a qualification to ensure
9483 -- the generation of a constraint check. This was previously
9484 -- for scalar types. For array types apply a length check, given
9485 -- that the context in general allows sliding, while a qualified
9486 -- expression forces equality of bounds.
9488 -----------------
9489 -- Apply_Check --
9490 -----------------
9496 begin
9501 or else Inside_A_Generic
9502 then
9508 else
9518 -- Local variables
9524 -- So in most cases the type of the if_expression and of its
9525 -- dependent expressions is that of the context. However, if
9526 -- the expression is the index of an Indexed_Component, we must
9527 -- ensure that a proper index check is applied, rather than a
9528 -- range check on the index type (which might be discriminant
9529 -- dependent). In this case we resolve with the base type of the
9530 -- index type, and the index check is generated in the resolution
9531 -- of the indexed_component above.
9533 -- Start of processing for Resolve_If_Expression
9535 begin
9536 -- Defend against malformed expressions
9545 then
9548 else
9568 -- If ELSE expression present, just resolve using the determined type
9576 -- Apply RM 4.5.7 (17/3): whether the expression is statically or
9577 -- dynamically tagged must be known statically.
9582 then
9588 -- If no ELSE expression is present, root type must be Standard.Boolean
9589 -- and we provide a Standard.True result converted to the appropriate
9590 -- Boolean type (in case it is a derived boolean type).
9593 Else_Expr :=
9598 else
9612 ----------------------------------
9613 -- Resolve_Implicit_Dereference --
9614 ----------------------------------
9619 begin
9627 -------------------------------
9628 -- Resolve_Indexed_Component --
9629 -------------------------------
9637 begin
9645 -- Use the context type to select the prefix that yields the correct
9646 -- component type.
9648 declare
9654 begin
9661 and then
9662 Covers
9665 then
9674 else
9680 else
9691 else
9698 -- If the prefix's type is an access type, get to the real array type.
9699 -- Note: we do not apply an access check because an explicit dereference
9700 -- will be introduced later, and the check will happen there.
9706 -- If name was overloaded, set component type correctly now.
9707 -- If a misplaced call to an entry family (which has no index types)
9708 -- return. Error will be diagnosed from calling context.
9712 else
9719 -- The prefix may have resolved to a string literal, in which case its
9720 -- etype has a special representation. This is only possible currently
9721 -- if the prefix is a static concatenation, written in functional
9722 -- notation.
9727 else
9742 -- Do not generate the warning on suspicious index if we are analyzing
9743 -- package Ada.Tags; otherwise we will report the warning with the
9744 -- Prims_Ptr field of the dispatch table.
9747 or else not
9749 then
9754 -- If the array type is atomic and the component is not, then this is
9755 -- worth a warning before Ada 2022, since we have a situation where the
9756 -- access to the component may cause extra read/writes of the atomic
9757 -- object, or partial word accesses, both of which may be unexpected.
9763 and then Has_Atomic_Components
9767 then
9768 Error_Msg_N
9770 Error_Msg_N
9775 -----------------------------
9776 -- Resolve_Integer_Literal --
9777 -----------------------------
9780 begin
9785 -----------------------------------------
9786 -- Resolve_Interpolated_String_Literal --
9787 -----------------------------------------
9790 is
9793 begin
9799 -- Resolve string elements using the context type; for interpolated
9800 -- expressions there is no need to check if their type has a suitable
9801 -- image function because under Ada 2022 all the types have such
9802 -- function available.
9814 --------------------------------
9815 -- Resolve_Intrinsic_Operator --
9816 --------------------------------
9823 -- True if this is the special mod operator of System.Storage_Elements,
9824 -- which needs to be resolved to the type of the left operand in order
9825 -- to implement the correct semantics.
9831 -- The base type to be used for the operator
9834 -- If the operand is a literal, it cannot be the expression in a
9835 -- conversion. Use a qualified expression instead.
9837 ---------------------
9838 -- Convert_Operand --
9839 ---------------------
9845 begin
9847 Res :=
9853 else
9860 -- Local variables
9866 -- Start of processing for Resolve_Intrinsic_Operator
9868 begin
9869 -- We must preserve the original entity in a generic setting, so that
9870 -- the legality of the operation can be verified in an instance.
9885 -- If the result or operand types are private, rewrite with unchecked
9886 -- conversions on the operands and the result, to expose the proper
9887 -- underlying numeric type. Likewise for the special mod operator of
9888 -- System.Storage_Elements, to expose the modified base type.
9893 or else Is_Stoele_Mod
9894 then
9899 else
9920 then
9921 -- Add explicit conversion where needed, and save interpretations in
9922 -- case operands are overloaded.
9929 else
9935 else
9945 else
9950 --------------------------------------
9951 -- Resolve_Intrinsic_Unary_Operator --
9952 --------------------------------------
9954 procedure Resolve_Intrinsic_Unary_Operator
9957 is
9962 begin
9981 else
9986 ------------------------
9987 -- Resolve_Logical_Op --
9988 ------------------------
9993 begin
9996 -- Predefined operations on scalar types yield the base type. On the
9997 -- other hand, logical operations on arrays yield the type of the
9998 -- arguments (and the context).
10002 else
10006 -- The following test is required because the operands of the operation
10007 -- may be literals, in which case the resulting type appears to be
10008 -- compatible with a signed integer type, when in fact it is compatible
10009 -- only with modular types. If the context itself is universal, the
10010 -- operation is illegal.
10018 Error_Msg_N
10026 then
10030 -- Replace AND by AND THEN, or OR by OR ELSE, if Short_Circuit_And_Or
10031 -- is active and the result type is standard Boolean (do not mess with
10032 -- ops that return a nonstandard Boolean type, because something strange
10033 -- is going on).
10035 -- Note: you might expect this replacement to be done during expansion,
10036 -- but that doesn't work, because when the pragma Short_Circuit_And_Or
10037 -- is used, no part of the right operand of an "and" or "or" operator
10038 -- should be executed if the left operand would short-circuit the
10039 -- evaluation of the corresponding "and then" or "or else". If we left
10040 -- the replacement to expansion time, then run-time checks associated
10041 -- with such operands would be evaluated unconditionally, due to being
10042 -- before the condition prior to the rewriting as short-circuit forms
10043 -- during expansion.
10045 if Short_Circuit_And_Or
10048 then
10049 -- Mark the corresponding putative SCO operator as truly a logical
10050 -- (and short-circuit) operator.
10063 -- Case of OR changed to OR ELSE
10065 else
10073 -- Return now, since analysis of the rewritten ops will take care of
10074 -- other reference bookkeeping and expression folding.
10090 ---------------------------------
10091 -- Resolve_Membership_Equality --
10092 ---------------------------------
10097 begin
10098 -- RM 4.5.2(4.1/3): if the type is limited, then it shall have a visible
10099 -- primitive equality operator. This means that we can use the regular
10100 -- visibility-based resolution and reset Entity in order to trigger it.
10105 -- RM 4.5.2(28.1/3): if the type is a record, then the membership test
10106 -- uses the primitive equality for the type [even if it is not visible].
10107 -- We only deal with the untagged case here, because the tagged case is
10108 -- handled uniformly in the expander.
10111 declare
10114 begin
10122 ---------------------------
10123 -- Resolve_Membership_Op --
10124 ---------------------------
10126 -- The context can only be a boolean type, and does not determine the
10127 -- arguments. Arguments should be unambiguous, but the preference rule for
10128 -- universal types applies.
10138 -- Analysis has determined a unique type for the left operand. Use it as
10139 -- the basis to resolve the disjuncts.
10141 ----------------------------
10142 -- Resolve_Set_Membership --
10143 ----------------------------
10148 begin
10149 -- If the left operand is overloaded, find type compatible with not
10150 -- overloaded alternative of the right operand.
10159 else
10164 -- Unclear how to resolve expression if all alternatives are also
10165 -- overloaded.
10171 else
10180 -- Alternative is an expression, a range
10181 -- or a subtype mark.
10185 then
10192 -- Check for duplicates for discrete case
10195 declare
10204 begin
10205 -- Loop checking duplicates. This is quadratic, but giant sets
10206 -- are unlikely in this context so it's a reasonable choice.
10213 | N_Character_Literal
10214 | N_Has_Entity
10215 then
10232 -- RM 4.5.2 (28.1/3) specifies that for types other than records or
10233 -- limited types, evaluation of a membership test uses the predefined
10234 -- equality for the type. This may be confusing to users, and the
10235 -- following warning appears useful for the most common case.
10239 then
10240 Error_Msg_NE
10242 Error_Msg_N
10247 -- Start of processing for Resolve_Membership_Op
10249 begin
10255 Resolve_Set_Membership;
10261 then
10264 -- If the left operand is of a universal numeric type and the right
10265 -- operand is not, we do not resolve the operands to the tested type
10266 -- but to the universal type instead. If not conforming to the letter,
10267 -- it's conforming to the spirit of the specification of membership
10268 -- tests, which are typically used to guard a specific operation and
10269 -- ought not to fail a check in doing so. Without this, in the case of
10271 -- type Small_Length is range 1 .. 16;
10273 -- function Is_Small_String (S : String) return Boolean is
10274 -- begin
10275 -- return S'Length in Small_Length;
10276 -- end;
10278 -- the function Is_Small_String would fail a range check for strings
10279 -- larger than 127 characters.
10281 -- The test on the size is required in GNAT because universal_integer
10282 -- does not cover all the values of all the supported integer types,
10283 -- for example the large values of Long_Long_Long_Unsigned.
10288 or else
10290 and then
10292 or else
10294 then
10297 -- If the right operand is 'Range, we first need to resolve it (to
10298 -- the tested type) so that it is rewritten as an N_Range, before
10299 -- converting its bounds and resolving it again below.
10303 then
10307 -- If the right operand is an N_Range, we convert its bounds to the
10308 -- universal type before resolving it.
10318 -- Ada 2005 (AI-251): Support the following case:
10320 -- type I is interface;
10321 -- type T is tagged ...
10323 -- function Test (O : I'Class) is
10324 -- begin
10325 -- return O in T'Class.
10326 -- end Test;
10328 -- In this case we have nothing else to do. The membership test will be
10329 -- done at run time.
10335 then
10338 else
10342 -- If mixed-mode operations are present and operands are all literal,
10343 -- the only interpretation involves Duration, which is probably not
10344 -- the intention of the programmer.
10359 then
10365 else
10370 -- Here after resolving membership operation
10377 ------------------
10378 -- Resolve_Null --
10379 ------------------
10384 begin
10385 -- Handle restriction against anonymous null access values This
10386 -- restriction can be turned off using -gnatdj.
10388 -- Ada 2005 (AI-231): Remove restriction
10391 and then not Debug_Flag_J
10394 then
10395 -- In the common case of a call which uses an explicitly null value
10396 -- for an access parameter, give specialized error message.
10399 Error_Msg_N
10402 -- Standard message for all other cases (are there any?)
10404 else
10405 Error_Msg_N
10410 -- Ada 2005 (AI-231): Generate the null-excluding check in case of
10411 -- assignment to a null-excluding object.
10416 then
10419 -- Decide whether to generate an if_statement around our
10420 -- null-excluding check to avoid them on certain internal object
10421 -- declarations by looking at the type the current Init_Proc
10422 -- belongs to.
10424 -- Generate:
10425 -- if T1b_skip_null_excluding_check then
10426 -- [constraint_error "access check failed"]
10427 -- end if;
10429 if Needs_Conditional_Null_Excluding_Check
10431 then
10434 Condition =>
10436 New_External_Name
10438 Then_Statements =>
10439 New_List (
10443 -- Otherwise, simply create the check
10445 else
10450 else
10451 Insert_Action
10459 -- In a distributed context, null for a remote access to subprogram may
10460 -- need to be replaced with a special record aggregate. In this case,
10461 -- return after having done the transformation.
10466 then
10470 -- The null literal takes its type from the context
10475 -----------------------
10476 -- Resolve_Op_Concat --
10477 -----------------------
10481 -- We wish to avoid deep recursion, because concatenations are often
10482 -- deeply nested, as in A&B&...&Z. Therefore, we walk down the left
10483 -- operands nonrecursively until we find something that is not a simple
10484 -- concatenation (A in this case). We resolve that, and then walk back
10485 -- up the tree following Parent pointers, calling Resolve_Op_Concat_Rest
10486 -- to do the rest of the work at each level. The Parent pointers allow
10487 -- us to avoid recursion, and thus avoid running out of memory. See also
10488 -- Sem_Ch4.Analyze_Concatenation, where a similar approach is used.
10493 begin
10494 -- The following code is equivalent to:
10496 -- Resolve_Op_Concat_First (NN, Typ);
10497 -- Resolve_Op_Concat_Arg (N, ...);
10498 -- Resolve_Op_Concat_Rest (N, Typ);
10500 -- where the Resolve_Op_Concat_Arg call recurses back here if the left
10501 -- operand is a concatenation.
10503 -- Walk down left operands
10505 loop
10514 -- Now (given the above example) NN is A&B and Op1 is A
10516 -- First resolve Op1 ...
10520 -- ... then walk NN back up until we reach N (where we started), calling
10521 -- Resolve_Op_Concat_Rest along the way.
10523 loop
10530 ---------------------------
10531 -- Resolve_Op_Concat_Arg --
10532 ---------------------------
10534 procedure Resolve_Op_Concat_Arg
10539 is
10543 begin
10545 if Is_Comp
10549 then
10551 else
10555 -- If both Array & Array and Array & Component are visible, there is a
10556 -- potential ambiguity that must be reported.
10561 then
10565 -- If the operation is user-defined and not overloaded use its
10566 -- profile. The operation may be a renaming, in which case it has
10567 -- been rewritten, and we want the original profile.
10572 then
10574 Etype
10578 -- Otherwise an aggregate may match both the array type and the
10579 -- component type.
10581 else
10586 else
10590 then
10591 declare
10596 begin
10601 -- Special-case the error message when the overloading is
10602 -- caused by a function that yields an array and can be
10603 -- called without parameters.
10608 Error_Msg_NE
10610 Error_Msg_NE
10614 else
10622 or else
10624 then
10625 Error_Msg_N -- CODEFIX
10642 then
10643 -- Determine if the out-of-range violation constitutes a
10644 -- warning or an error according to the expression base type,
10645 -- according to Ada 2022 RM 4.9 (35/2).
10648 Apply_Compile_Time_Constraint_Error
10654 Apply_Compile_Time_Constraint_Error
10663 else
10668 else
10675 -----------------------------
10676 -- Resolve_Op_Concat_First --
10677 -----------------------------
10684 begin
10685 -- The parser folds an enormous sequence of concatenations of string
10686 -- literals into "" & "...", where the Is_Folded_In_Parser flag is set
10687 -- in the right operand. If the expression resolves to a predefined "&"
10688 -- operator, all is well. Otherwise, the parser's folding is wrong, so
10689 -- we give an error. See P_Simple_Expression in Par.Ch4.
10694 then
10709 ----------------------------
10710 -- Resolve_Op_Concat_Rest --
10711 ----------------------------
10717 begin
10726 -- If this is not a static concatenation, but the result is a string
10727 -- type (and not an array of strings) ensure that static string operands
10728 -- have their subtypes properly constructed.
10732 then
10738 ----------------------
10739 -- Resolve_Op_Expon --
10740 ----------------------
10745 begin
10746 -- Catch attempts to do fixed-point exponentiation with universal
10747 -- operands, which is a case where the illegality is not caught during
10748 -- normal operator analysis. This is not done in preanalysis mode
10749 -- since the tree is not fully decorated during preanalysis.
10761 then
10770 then
10780 -- We do the resolution using the base type, because intermediate values
10781 -- in expressions are always of the base type, not a subtype of it.
10786 -- For integer types, right argument must be in Natural range
10801 -- Evaluate the exponentiation operator for dimensioned type
10804 else
10808 -- Set overflow checking bit. Much cleverer code needed here eventually
10809 -- and perhaps the Resolve routines should be separated for the various
10810 -- arithmetic operations, since they will need different processing. ???
10819 --------------------
10820 -- Resolve_Op_Not --
10821 --------------------
10825 -- This function determines if the parent node is a boolean operator or
10826 -- operation (comparison op, membership test, or short circuit form) and
10827 -- the not in question is the left operand of this operation. Note that
10828 -- if the not is in parens, then false is returned.
10830 -----------------------
10831 -- Parent_Is_Boolean --
10832 -----------------------
10835 begin
10838 | N_Op_Boolean
10839 | N_Short_Circuit
10843 -- Local variables
10847 -- Start of processing for Resolve_Op_Not
10849 begin
10850 -- Predefined operations on scalar types yield the base type. On the
10851 -- other hand, logical operations on arrays yield the type of the
10852 -- arguments (and the context).
10856 else
10860 -- Straightforward case of incorrect arguments
10867 -- Special case of probable missing parens
10871 Error_Msg_N
10874 else
10875 Error_Msg_N
10882 -- OK resolution of NOT
10884 else
10885 -- Warn if non-boolean types involved. This is a case like not a < b
10886 -- where a and b are modular, where we will get (not a) < b and most
10887 -- likely not (a < b) was intended.
10889 if Warn_On_Questionable_Missing_Parens
10891 and then Parent_Is_Boolean
10892 then
10896 -- Warn on double negation if checking redundant constructs
10898 if Warn_On_Redundant_Constructs
10903 then
10907 -- Complete resolution and evaluation of NOT
10917 -----------------------------
10918 -- Resolve_Operator_Symbol --
10919 -----------------------------
10921 -- Nothing to be done, all resolved already
10927 begin
10931 ----------------------------------
10932 -- Resolve_Qualified_Expression --
10933 ----------------------------------
10941 begin
10945 -- A qualified expression requires an exact match of the type, class-
10946 -- wide matching is not allowed. However, if the qualifying type is
10947 -- specific and the expression has a class-wide type, it may still be
10948 -- okay, since it can be the result of the expansion of a call to a
10949 -- dispatching function, so we also have to check class-wideness of the
10950 -- type of the expression's original node.
10953 or else
10957 then
10961 -- If the target type is unconstrained, then we reset the type of the
10962 -- result from the type of the expression. For other cases, the actual
10963 -- subtype of the expression is the target type. But we avoid doing it
10964 -- for an allocator since this is not needed and might be problematic.
10969 then
10976 -- If we still have a qualified expression after the static evaluation,
10977 -- then apply a scalar range check if needed. The reason that we do this
10978 -- after the Eval call is that otherwise, the application of the range
10979 -- check may convert an illegal static expression and result in warning
10980 -- rather than giving an error (e.g Integer'(Integer'Last + 1)).
10984 then
10988 -- AI12-0100: Once the qualified expression is resolved, check whether
10989 -- operand satisfies a static predicate of the target subtype, if any.
10990 -- In the static expression case, a predicate check failure is an error.
10993 Check_Expression_Against_Static_Predicate
10998 ------------------------------
10999 -- Resolve_Raise_Expression --
11000 ------------------------------
11003 begin
11008 else
11011 -- Apply check for required parentheses in the enclosing
11012 -- context of raise_expressions (RM 11.3 (2)), including default
11013 -- expressions in contexts that can include aspect specifications,
11014 -- and ancestor parts of extension aggregates.
11016 declare
11020 begin
11023 loop
11030 then
11037 if not Parentheses_Found
11039 and then
11041 | N_Floating_Point_Definition
11042 | N_Ordinary_Fixed_Point_Definition
11043 | N_Decimal_Fixed_Point_Definition
11044 | N_Extension_Aggregate
11045 | N_Discriminant_Specification
11046 | N_Parameter_Specification
11047 | N_Formal_Object_Declaration
11050 and then
11052 then
11053 Error_Msg_N
11055 N);
11061 -------------------
11062 -- Resolve_Range --
11063 -------------------
11070 -- Returns True if N is of the form X'First .. X'Last where X is the
11071 -- same entity for both attributes.
11073 --------------------
11074 -- First_Last_Ref --
11075 --------------------
11081 begin
11086 then
11087 declare
11090 begin
11100 -- Start of processing for Resolve_Range
11102 begin
11108 -- Reanalyze the lower bound after both bounds have been analyzed, so
11109 -- that the range is known to be static or not by now. This may trigger
11110 -- more compile-time evaluation, which is useful for static analysis
11111 -- with GNATprove. This is not needed for compilation or static analysis
11112 -- with CodePeer, as full expansion does that evaluation then.
11119 -- Check for inappropriate range on unordered enumeration type
11123 -- Exclude X'First .. X'Last if X is the same entity for both
11125 and then not First_Last_Ref
11126 then
11128 Error_Msg_NE
11135 -- We have to check the bounds for being within the base range as
11136 -- required for a non-static context. Normally this is automatic and
11137 -- done as part of evaluating expressions, but the N_Range node is an
11138 -- exception, since in GNAT we consider this node to be a subexpression,
11139 -- even though in Ada it is not. The circuit in Sem_Eval could check for
11140 -- this, but that would put the test on the main evaluation path for
11141 -- expressions.
11146 -- Check for an ambiguous range over character literals. This will
11147 -- happen with a membership test involving only literals.
11155 -- If bounds are static, constant-fold them, so size computations are
11156 -- identical between front-end and back-end. Do not perform this
11157 -- transformation while analyzing generic units, as type information
11158 -- would be lost when reanalyzing the constant node in the instance.
11170 -- If we have a compile-time-known null range, we warn, because that is
11171 -- likely to be a mistake. (Dynamic null ranges make sense, but often
11172 -- compile-time-known ones do not.) Warn only if this is in a subtype
11173 -- declaration. We do this here, rather than while analyzing a subtype
11174 -- declaration, in case we decide to expand the cases. We do not want to
11175 -- warn in all cases, because some are idiomatic, such as an empty
11176 -- aggregate (1 .. 0 => <>).
11178 -- We don't warn in generics or their instances, because there might be
11179 -- some instances where the range is null, and some where it is not,
11180 -- which would lead to false alarms.
11184 and then Compile_Time_Compare
11190 then
11195 --------------------------
11196 -- Resolve_Real_Literal --
11197 --------------------------
11202 begin
11203 -- Special processing for fixed-point literals to make sure that the
11204 -- value is an exact multiple of the small where this is required. We
11205 -- skip this for the universal real case, and also for generic types.
11211 then
11212 -- We must freeze the base type to get the proper value of the small
11218 declare
11225 begin
11226 -- Case of literal is not an exact multiple of the Small
11230 -- For a source program literal for a decimal fixed-point type,
11231 -- this is statically illegal (RM 4.9(36)).
11236 then
11240 -- Generate a warning if literal from source
11243 and then Warn_On_Bad_Fixed_Value
11244 then
11245 Error_Msg_N
11247 N);
11250 -- Replace literal by a value that is the exact representation
11251 -- of a value of the type, i.e. a multiple of the small value,
11252 -- by truncation, since Machine_Rounds is false for all GNAT
11253 -- fixed-point types (RM 4.9(38)).
11263 -- In all cases, set the corresponding integer field
11269 -- Now replace the actual type by the expected type as usual
11275 -----------------------
11276 -- Resolve_Reference --
11277 -----------------------
11282 begin
11283 -- Replace general access with specific type
11291 -- If we are taking the reference of a volatile entity, then treat it as
11292 -- a potential modification of this entity. This is too conservative,
11293 -- but necessary because remove side effects can cause transformations
11294 -- of normal assignments into reference sequences that otherwise fail to
11295 -- notice the modification.
11302 --------------------------------
11303 -- Resolve_Selected_Component --
11304 --------------------------------
11319 -- Check whether this is the initialization of a component within an
11320 -- init proc (by assignment or call to another init proc). If true,
11321 -- there is no need for a discriminant check.
11323 --------------------
11324 -- Init_Component --
11325 --------------------
11328 begin
11329 return Inside_Init_Proc
11335 -- Start of processing for Resolve_Selected_Component
11337 begin
11340 -- Use the context type to select the prefix that has a selector
11341 -- of the correct name and type.
11349 else
11353 -- Locate selected component. For a private prefix the selector
11354 -- can denote a discriminant.
11358 -- The visible components of a class-wide type are those of
11359 -- the root type.
11369 then
11376 else
11380 Error_Msg_N
11385 else
11388 -- There may be an implicit dereference. Retrieve
11389 -- designated record type.
11393 else
11399 -- Resolution chooses the new interpretation.
11400 -- Find the component with the right name.
11405 loop
11422 -- There must be a legal interpretation at this point
11427 -- In general the expected type is the type of the context, not the
11428 -- type of the candidate selected component.
11433 -- The type of the context and that of the component are
11434 -- compatible and in general identical, but if they are anonymous
11435 -- access-to-subprogram types, the relevant type is that of the
11436 -- component. This matters in Unnest_Subprograms mode, where the
11437 -- relevant context is the one in which the type is declared, not
11438 -- the point of use. This determines what activation record to use.
11443 -- When the type of the component is an access to a class-wide type
11444 -- the relevant type is that of the component (since in such case we
11445 -- may need to generate implicit type conversions or dispatching
11446 -- calls).
11451 then
11455 else
11456 -- Resolve prefix with its type
11461 -- Generate cross-reference. We needed to wait until full overloading
11462 -- resolution was complete to do this, since otherwise we can't tell if
11463 -- we are an lvalue or not.
11467 else
11471 -- If the prefix's type is an access type, get to the real record type.
11472 -- Note: we do not apply an access check because an explicit dereference
11473 -- will be introduced later, and the check will happen there.
11479 else
11483 -- Set flag for expander if discriminant check required on a component
11484 -- appearing within a variant.
11490 and then
11493 and then not Init_Component
11494 then
11502 -- If the prefix is a record conversion, this may be a renamed
11503 -- discriminant whose bounds differ from those of the original
11504 -- one, so we must ensure that a range check is performed.
11509 then
11513 -- Eval_Selected_Component may e.g. fold statically known discriminants.
11519 -- If the record type is atomic and the component is not, then this
11520 -- is worth a warning before Ada 2022, since we have a situation
11521 -- where the access to the component may cause extra read/writes of
11522 -- the atomic object, or partial word accesses, both of which may be
11523 -- unexpected.
11529 then
11530 Error_Msg_N
11533 Error_Msg_N
11543 -------------------
11544 -- Resolve_Shift --
11545 -------------------
11552 begin
11553 -- We do the resolution using the base type, because intermediate values
11554 -- in expressions always are of the base type, not a subtype of it.
11567 ---------------------------
11568 -- Resolve_Short_Circuit --
11569 ---------------------------
11576 begin
11577 -- Ensure all actions associated with the left operand (e.g.
11578 -- finalization of transient objects) are fully evaluated locally within
11579 -- an expression with actions. This is particularly helpful for coverage
11580 -- analysis. However this should not happen in generics or if option
11581 -- Minimize_Expression_With_Actions is set.
11584 declare
11586 begin
11594 -- Set Comes_From_Source on L to preserve warnings for unset
11595 -- reference.
11604 -- Check for issuing warning for always False assert/check, this happens
11605 -- when assertions are turned off, in which case the pragma Assert/Check
11606 -- was transformed into:
11608 -- if False and then <condition> then ...
11610 -- and we detect this pattern
11612 if Warn_On_Assertion_Failure
11619 then
11620 declare
11623 begin
11624 -- Special handling of Asssert pragma
11628 then
11629 declare
11631 Original_Node
11632 (Expression
11635 begin
11636 -- Don't warn if original condition is explicit False,
11637 -- since obviously the failure is expected in this case.
11641 then
11644 -- Issue warning. We do not want the deletion of the
11645 -- IF/AND-THEN to take this message with it. We achieve this
11646 -- by making sure that the expanded code points to the Sloc
11647 -- of the expression, not the original pragma.
11649 else
11650 -- Note: Use Error_Msg_F here rather than Error_Msg_N.
11651 -- The source location of the expression is not usually
11652 -- the best choice here. For example, it gets located on
11653 -- the last AND keyword in a chain of boolean expressiond
11654 -- AND'ed together. It is best to put the message on the
11655 -- first character of the assertion, which is the effect
11656 -- of the First_Node call here.
11658 Error_Msg_F
11660 Expression
11665 -- Similar processing for Check pragma
11669 then
11670 -- Don't want to warn if original condition is explicit False
11672 declare
11674 Original_Node
11675 (Expression
11677 begin
11680 then
11683 -- Post warning
11685 else
11686 -- Again use Error_Msg_F rather than Error_Msg_N, see
11687 -- comment above for an explanation of why we do this.
11689 Error_Msg_F
11691 Expression
11699 -- Continue with processing of short circuit
11708 -------------------
11709 -- Resolve_Slice --
11710 -------------------
11719 begin
11722 -- Use the context type to select the prefix that yields the correct
11723 -- array type.
11725 declare
11731 begin
11739 then
11747 else
11752 else
11763 else
11769 -- If the prefix's type is an access type, get to the real array type.
11770 -- Note: we do not apply an access check because an explicit dereference
11771 -- will be introduced later, and the check will happen there.
11776 -- If the prefix is an access to an unconstrained array, we must use
11777 -- the actual subtype of the object to perform the index checks. The
11778 -- object denoted by the prefix is implicit in the node, so we build
11779 -- an explicit representation for it in order to compute the actual
11780 -- subtype.
11785 declare
11789 begin
11796 -- In CodePeer mode the attribute Image is not expanded, so when it
11797 -- acts as a prefix of a slice, we handle it like a call to function
11798 -- returning an unconstrained string. Same for the Wide variants of
11799 -- attribute Image.
11808 | Name_Wide_Image
11809 | Name_Wide_Wide_Image)
11810 then
11813 -- If the name is a selected component that depends on discriminants,
11814 -- build an actual subtype for it. This can happen only when the name
11815 -- itself is overloaded; otherwise the actual subtype is created when
11816 -- the selected component is analyzed.
11819 and then Full_Analysis
11821 then
11822 declare
11825 begin
11830 -- Maybe this should just be "else", instead of checking for the
11831 -- specific case of slice??? This is needed for the case where the
11832 -- prefix is an Image attribute, which gets expanded to a slice, and so
11833 -- has a constrained subtype which we want to use for the slice range
11834 -- check applied below (the range check won't get done if the
11835 -- unconstrained subtype of the 'Image is used).
11841 -- Obtain the type of the array index
11845 else
11849 -- If name was overloaded, set slice type correctly now
11853 -- Handle the generation of a range check that compares the array index
11854 -- against the discrete_range. The check is not applied to internally
11855 -- built nodes associated with the expansion of dispatch tables. Check
11856 -- that Ada.Tags has already been loaded to avoid extra dependencies on
11857 -- the unit.
11859 if Tagged_Type_Expansion
11865 then
11868 -- The discrete_range is specified by a subtype name. Create an
11869 -- equivalent range attribute, apply checks to this attribute, but
11870 -- insert them into the range expression of the slice itself.
11873 Dexpr :=
11874 Make_Attribute_Reference
11876 Prefix =>
11885 -- The discrete_range is a regular range (or a range attribute, which
11886 -- will be resolved into a regular range). Resolve the bounds and remove
11887 -- their side effects.
11889 else
11906 -- Check bad use of type with predicates
11908 declare
11911 begin
11914 then
11916 else
11921 Bad_Predicated_Subtype_Use
11926 -- Otherwise here is where we check suspicious indexes
11938 ----------------------------
11939 -- Resolve_String_Literal --
11940 ----------------------------
11951 begin
11952 -- For a string appearing in a concatenation, defer creation of the
11953 -- string_literal_subtype until the end of the resolution of the
11954 -- concatenation, because the literal may be constant-folded away. This
11955 -- is a useful optimization for long concatenation expressions.
11957 -- If the string is an aggregate built for a single character (which
11958 -- happens in a non-static context) or a is null string to which special
11959 -- checks may apply, we build the subtype. Wide strings must also get a
11960 -- string subtype if they come from a one character aggregate. Strings
11961 -- generated by attributes might be static, but it is often hard to
11962 -- determine whether the enclosing context is static, so we generate
11963 -- subtypes for them as well, thus losing some rarer optimizations ???
11964 -- Same for strings that come from a static conversion.
11966 Need_Check :=
11975 -- If the resolving type is itself a string literal subtype, we can just
11976 -- reuse it, since there is no point in creating another.
11982 and then not Need_Check
11984 | N_Attribute_Reference
11985 | N_Qualified_Expression
11986 | N_Type_Conversion
11987 then
11990 -- Do not generate a string literal subtype for the default expression
11991 -- of a formal parameter in GNATprove mode. This is because the string
11992 -- subtype is associated with the freezing actions of the subprogram,
11993 -- however freezing is disabled in GNATprove mode and as a result the
11994 -- subtype is unavailable.
11996 elsif GNATprove_Mode
11998 then
12001 -- Otherwise we must create a string literal subtype. Note that the
12002 -- whole idea of string literal subtypes is simply to avoid the need
12003 -- for building a full fledged array subtype for each literal.
12005 else
12011 or else Need_Check
12012 then
12019 then
12025 -- The validity of a null string has been checked in the call to
12026 -- Eval_String_Literal.
12031 -- Always accept string literal with component type Any_Character, which
12032 -- occurs in error situations and in comparisons of literals, both of
12033 -- which should accept all literals.
12038 -- If the type is bit-packed, then we always transform the string
12039 -- literal into a full fledged aggregate.
12044 -- Deal with cases of Wide_Wide_String, Wide_String, and String
12046 else
12047 -- For Standard.Wide_Wide_String, or any other type whose component
12048 -- type is Standard.Wide_Wide_Character, we know that all the
12049 -- characters in the string must be acceptable, since the parser
12050 -- accepted the characters as valid character literals.
12055 -- For the case of Standard.String, or any other type whose component
12056 -- type is Standard.Character, we must make sure that there are no
12057 -- wide characters in the string, i.e. that it is entirely composed
12058 -- of characters in range of type Character.
12060 -- If the string literal is the result of a static concatenation, the
12061 -- test has already been performed on the components, and need not be
12062 -- repeated.
12066 then
12070 -- If we are out of range, post error. This is one of the
12071 -- very few places that we place the flag in the middle of
12072 -- a token, right under the offending wide character. Not
12073 -- quite clear if this is right wrt wide character encoding
12074 -- sequences, but it's only an error message.
12076 Error_Msg
12083 -- For the case of Standard.Wide_String, or any other type whose
12084 -- component type is Standard.Wide_Character, we must make sure that
12085 -- there are no wide characters in the string, i.e. that it is
12086 -- entirely composed of characters in range of type Wide_Character.
12088 -- If the string literal is the result of a static concatenation,
12089 -- the test has already been performed on the components, and need
12090 -- not be repeated.
12094 then
12098 -- If we are out of range, post error. This is one of the
12099 -- very few places that we place the flag in the middle of
12100 -- a token, right under the offending wide character.
12102 -- This is not quite right, because characters in general
12103 -- will take more than one character position ???
12105 Error_Msg
12112 -- If the root type is not a standard character, then we will convert
12113 -- the string into an aggregate and will let the aggregate code do
12114 -- the checking. Standard Wide_Wide_Character is also OK here.
12116 else
12120 -- See if the component type of the array corresponding to the string
12121 -- has compile time known bounds. If yes we can directly check
12122 -- whether the evaluation of the string will raise constraint error.
12123 -- Otherwise we need to transform the string literal into the
12124 -- corresponding character aggregate and let the aggregate code do
12125 -- the checking. We use the same transformation if the component
12126 -- type has a static predicate, which will be applied to each
12127 -- character when the aggregate is resolved.
12131 -- Check for the case of full range, where we are definitely OK
12137 -- Here the range is not the complete base type range, so check
12139 declare
12147 begin
12150 then
12156 then
12157 Apply_Compile_Time_Constraint_Error
12159 CE_Range_Check_Failed,
12172 -- If we got here we meed to transform the string literal into the
12173 -- equivalent qualified positional array aggregate. This is rather
12174 -- heavy artillery for this situation, but it is hard work to avoid.
12176 declare
12181 begin
12182 -- Build the character literals, we give them source locations that
12183 -- correspond to the string positions, which is a bit tricky given
12184 -- the possible presence of wide character escape sequences.
12198 -- Should we have a call to Skip_Wide here ???
12200 -- ??? else
12201 -- Skip_Wide (P);
12209 Expression =>
12216 -------------------------
12217 -- Resolve_Target_Name --
12218 -------------------------
12221 begin
12225 -----------------------------
12226 -- Resolve_Type_Conversion --
12227 -----------------------------
12239 -- Set to False to suppress cases where we want to suppress the test
12240 -- for redundancy to avoid possible false positives on this warning.
12242 begin
12243 if not Conv_OK
12245 then
12249 -- If the Operand Etype is Universal_Fixed, then the conversion is
12250 -- never redundant. We need this check because by the time we have
12251 -- finished the rather complex transformation, the conversion looks
12252 -- redundant when it is not.
12257 -- If the operand is marked as Any_Fixed, then special processing is
12258 -- required. This is also a case where we suppress the test for a
12259 -- redundant conversion, since most certainly it is not redundant.
12264 -- Mixed-mode operation involving a literal. Context must be a fixed
12265 -- type which is applied to the literal subsequently.
12267 -- Multiplication and division involving two fixed type operands must
12268 -- yield a universal real because the result is computed in arbitrary
12269 -- precision.
12275 then
12281 or else
12283 then
12284 -- Return if expression is ambiguous
12289 -- If nothing else, the available fixed type is Duration
12291 else
12295 -- Resolve the real operand with largest available precision
12299 else
12305 -- If the operand is a literal (it could be a non-static and
12306 -- illegal exponentiation) check whether the use of Duration
12307 -- is potentially inaccurate.
12312 then
12313 Error_Msg_N
12316 Error_Msg_N
12323 then
12326 else
12337 -- Note: we do the Eval_Type_Conversion call before applying the
12338 -- required checks for a subtype conversion. This is important, since
12339 -- both are prepared under certain circumstances to change the type
12340 -- conversion to a constraint error node, but in the case of
12341 -- Eval_Type_Conversion this may reflect an illegality in the static
12342 -- case, and we would miss the illegality (getting only a warning
12343 -- message), if we applied the type conversion checks first.
12347 -- Even when evaluation is not possible, we may be able to simplify the
12348 -- conversion or its expression. This needs to be done before applying
12349 -- checks, since otherwise the checks may use the original expression
12350 -- and defeat the simplifications. This is specifically the case for
12351 -- elimination of the floating-point Truncation attribute in
12352 -- float-to-int conversions.
12356 -- If after evaluation we still have a type conversion, then we may need
12357 -- to apply checks required for a subtype conversion. But skip them if
12358 -- universal fixed operands are involved, since range checks are handled
12359 -- separately for these cases, after the expansion done by Exp_Fixd.
12365 then
12369 -- Issue warning for conversion of simple object to its own type. We
12370 -- have to test the original nodes, since they may have been rewritten
12371 -- by various optimizations.
12375 -- Here we test for a redundant conversion if the warning mode is
12376 -- active (and was not locally reset), and we have a type conversion
12377 -- from source not appearing in a generic instance.
12379 if Test_Redundant
12382 and then not In_Instance
12383 then
12387 -- If the node is part of a larger expression, the Target_Type
12388 -- may not be the original type of the node if the context is a
12389 -- condition. Recover original type to see if conversion is needed.
12393 then
12397 -- If we have an entity name, then give the warning if the entity
12398 -- is the right type, or if it is a loop parameter covered by the
12399 -- original type (that's needed because loop parameters have an
12400 -- odd subtype coming from the bounds).
12404 and then
12406 or else
12410 -- If not an entity, then type of expression must match
12413 then
12414 -- One more check, do not give warning if the analyzed conversion
12415 -- has an expression with non-static bounds, and the bounds of the
12416 -- target are static. This avoids junk warnings in cases where the
12417 -- conversion is necessary to establish staticness, for example in
12418 -- a case statement.
12422 then
12425 -- Never give a warning if the operand is a conditional expression
12426 -- because RM 4.5.7(10/3) forces its type to be the target type.
12431 -- Finally, if this type conversion occurs in a context requiring
12432 -- a prefix, and the expression is a qualified expression then the
12433 -- type conversion is not redundant, since a qualified expression
12434 -- is not a prefix, whereas a type conversion is. For example, "X
12435 -- := T'(Funx(...)).Y;" is illegal because a selected component
12436 -- requires a prefix, but a type conversion makes it legal: "X :=
12437 -- T(T'(Funx(...))).Y;"
12439 -- In Ada 2012, a qualified expression is a name, so this idiom is
12440 -- no longer needed, but we still suppress the warning because it
12441 -- seems unfriendly for warnings to pop up when you switch to the
12442 -- newer language version.
12446 | N_Indexed_Component
12447 | N_Selected_Component
12448 | N_Slice
12449 | N_Explicit_Dereference
12450 then
12453 -- Never warn on conversion to Long_Long_Integer'Base since
12454 -- that is most likely an artifact of the extended overflow
12455 -- checking and comes from complex expanded code.
12460 -- Do not warn on conversion to class-wide type on helpers of
12461 -- class-wide preconditions because in this context the warning
12462 -- would be spurious (since the class-wide precondition has been
12463 -- installed in the return statement of the helper, which has a
12464 -- class-wide formal type instead of a regular tagged type).
12469 then
12472 -- Here we give the redundant conversion warning. If it is an
12473 -- entity, give the name of the entity in the message. If not,
12474 -- just mention the expression.
12476 else
12479 Error_Msg_NE -- CODEFIX
12482 else
12483 Error_Msg_NE
12491 -- Ada 2005 (AI-251): Handle class-wide interface type conversions.
12492 -- No need to perform any interface conversion if the type of the
12493 -- expression coincides with the target type.
12496 and then Expander_Active
12498 then
12499 declare
12503 begin
12504 -- If the type of the operand is a limited view, use nonlimited
12505 -- view when available. If it is a class-wide type, recover the
12506 -- class-wide type of the nonlimited view.
12510 then
12515 -- It seems that Non_Limited_View should also be applied for
12516 -- Target when it has a limited view, but that leads to missing
12517 -- error checks on interface conversions further below. ???
12522 -- If the type of the operand is a limited view, use nonlimited
12523 -- view when available. If it is a class-wide type, recover the
12524 -- class-wide type of the nonlimited view.
12528 then
12536 -- If the target type is a limited view, use nonlimited view
12537 -- when available.
12541 then
12549 -- Conversion from interface type
12551 -- It seems that it would be better for the error checks below
12552 -- to be performed as part of Validate_Conversion (and maybe some
12553 -- of the error checks above could be moved as well?). ???
12557 -- Ada 2005 (AI-217): Handle entities from limited views
12561 Error_Msg_NE -- CODEFIX
12564 Error_Msg_N
12566 N);
12569 and then not
12572 then
12574 Error_Msg_NE -- CODEFIX
12577 Error_Msg_N
12579 N);
12581 else
12585 -- Conversion to interface type
12593 -- Ada 2012: Once the type conversion is resolved, check whether the
12594 -- operand satisfies a static predicate of the target subtype, if any.
12595 -- In the static expression case, a predicate check failure is an error.
12598 Check_Expression_Against_Static_Predicate
12602 -- If at this stage we have a fixed to integer conversion, make sure the
12603 -- Do_Range_Check flag is set, because such conversions in general need
12604 -- a range check. We only need this if expansion is off, see above why.
12607 and then not Expander_Active
12612 then
12616 -- Generating C code a type conversion of an access to constrained
12617 -- array type to access to unconstrained array type involves building
12618 -- a fat pointer which in general cannot be generated on the fly. We
12619 -- remove side effects in order to store the result of the conversion
12620 -- into a temporary.
12622 if Modify_Tree_For_C
12629 then
12634 ----------------------
12635 -- Resolve_Unary_Op --
12636 ----------------------
12645 begin
12646 -- Deal with intrinsic unary operators
12652 then
12657 -- Deal with universal cases
12666 -- Generate warning for negative literal of a modular type, unless it is
12667 -- enclosed directly in a type qualification or a type conversion, as it
12668 -- is likely not what the user intended. We don't issue the warning for
12669 -- the common use of -1 to denote OxFFFF_FFFF...
12671 if Warn_On_Suspicious_Modulus_Value
12677 | N_Type_Conversion
12679 then
12680 Error_Msg_N
12685 Error_Msg_N
12689 -- Generate warning for expressions like abs (x mod 2)
12691 if Warn_On_Redundant_Constructs
12693 then
12697 Error_Msg_N -- CODEFIX
12702 -- Deal with reference generation
12709 -- Set overflow checking bit. Much cleverer code needed here eventually
12710 -- and perhaps the Resolve routines should be separated for the various
12711 -- arithmetic operations, since they will need different processing ???
12719 -- Generate warning for expressions like -5 mod 3 for integers. No need
12720 -- to worry in the floating-point case, since parens do not affect the
12721 -- result so there is no point in giving in a warning.
12723 declare
12732 begin
12733 if Warn_On_Questionable_Missing_Parens
12737 then
12740 -- We are looking for cases where the right operand is not
12741 -- parenthesized, and is a binary operator, multiply, divide, or
12742 -- mod. These are the cases where the grouping can affect results.
12746 then
12747 -- For mod, we always give the warning, since the value is
12748 -- affected by the parenthesization (e.g. (-5) mod 315 /=
12749 -- -(5 mod 315)). But for the other cases, the only concern is
12750 -- overflow, e.g. for the case of 8 big signed (-(2 * 64)
12751 -- overflows, but (-2) * 64 does not). So we try to give the
12752 -- message only when overflow is possible.
12756 then
12761 else
12767 else
12771 -- Note that the test below is deliberately excluding the
12772 -- largest negative number, since that is a potentially
12773 -- troublesome case (e.g. -2 * x, where the result is the
12774 -- largest negative integer has an overflow with 2 * x).
12781 -- For the multiplication case, the only case we have to worry
12782 -- about is when (-a)*b is exactly the largest negative number
12783 -- so that -(a*b) can cause overflow. This can only happen if
12784 -- a is a power of 2, and more generally if any operand is a
12785 -- constant that is not a power of 2, then the parentheses
12786 -- cannot affect whether overflow occurs. We only bother to
12787 -- test the left most operand
12789 -- Loop looking at left operands for one that has known value
12796 -- Operand value of 0 or 1 skips warning
12801 -- Otherwise check power of 2, if power of 2, warn, if
12802 -- anything else, skip warning.
12804 else
12808 else
12817 -- Keep looking at left operands
12822 -- For rem or "/" we can only have a problematic situation
12823 -- if the divisor has a value of minus one or one. Otherwise
12824 -- overflow is impossible (divisor > 1) or we have a case of
12825 -- division by zero in any case.
12830 then
12834 -- If we fall through warning should be issued
12836 -- Shouldn't we test Warn_On_Questionable_Missing_Parens ???
12838 Error_Msg_N
12845 ----------------------------------
12846 -- Resolve_Unchecked_Expression --
12847 ----------------------------------
12849 procedure Resolve_Unchecked_Expression
12852 is
12853 begin
12858 ---------------------------------------
12859 -- Resolve_Unchecked_Type_Conversion --
12860 ---------------------------------------
12862 procedure Resolve_Unchecked_Type_Conversion
12865 is
12871 begin
12872 -- Resolve operand using its own type
12876 -- If the expression is a conversion to universal integer of an
12877 -- an expression with an integer type, then we can eliminate the
12878 -- intermediate conversion to universal integer.
12883 then
12888 -- In an inlined context, the unchecked conversion may be applied
12889 -- to a literal, in which case its type is the type of the context.
12890 -- (In other contexts conversions cannot apply to literals).
12892 if In_Inlined_Body
12896 then
12904 ------------------------------
12905 -- Rewrite_Operator_As_Call --
12906 ------------------------------
12913 begin
12920 New_N :=
12931 ------------------------------
12932 -- Rewrite_Renamed_Operator --
12933 ------------------------------
12935 procedure Rewrite_Renamed_Operator
12939 is
12944 begin
12945 -- Do not perform this transformation within a pre/postcondition,
12946 -- because the expression will be reanalyzed, and the transformation
12947 -- might affect the visibility of the operator, e.g. in an instance.
12948 -- Note that fully analyzed and expanded pre/postconditions appear as
12949 -- pragma Check equivalents.
12955 -- Likewise when an expression function is being preanalyzed, since the
12956 -- expression will be reanalyzed as part of the generated body.
12959 declare
12961 begin
12964 N_Expression_Function
12965 then
12981 -- Indicate that both the original entity and its renaming are
12982 -- referenced at this point.
12989 -- If the context type is private, add the appropriate conversions so
12990 -- that the operator is applied to the full view. This is done in the
12991 -- routines that resolve intrinsic operators.
12995 when N_Op_Add
12996 | N_Op_Divide
12997 | N_Op_Expon
12998 | N_Op_Mod
12999 | N_Op_Multiply
13000 | N_Op_Rem
13001 | N_Op_Subtract
13002 =>
13005 when N_Op_Abs
13006 | N_Op_Minus
13007 | N_Op_Plus
13008 =>
13017 -----------------------
13018 -- Set_Slice_Subtype --
13019 -----------------------
13021 -- Build an implicit subtype declaration to represent the type delivered by
13022 -- the slice. This is an abbreviated version of an array subtype. We define
13023 -- an index subtype for the slice, using either the subtype name or the
13024 -- discrete range of the slice. To be consistent with index usage elsewhere
13025 -- we create a list header to hold the single index. This list is not
13026 -- otherwise attached to the syntax tree.
13037 begin
13043 else
13044 -- We force the evaluation of a range. This is definitely needed in
13045 -- the renamed case, and seems safer to do unconditionally. Note in
13046 -- any case that since we will create and insert an Itype referring
13047 -- to this range, we must make sure any side effect removal actions
13048 -- are inserted before the Itype definition.
13054 -- If the discrete range is given by a subtype indication, the
13055 -- type of the slice is the base of the subtype mark.
13058 declare
13060 begin
13069 -- Take a new copy of Drange (where bounds have been rewritten to
13070 -- reference side-effect-free names). Using a separate tree ensures
13071 -- that further expansion (e.g. while rewriting a slice assignment
13072 -- into a FOR loop) does not attempt to remove side effects on the
13073 -- bounds again (which would cause the bounds in the index subtype
13074 -- definition to refer to temporaries before they are defined) (the
13075 -- reason is that some names are considered side effect free here
13076 -- for the subtype, but not in the context of a loop iteration
13077 -- scheme).
13099 -- The Etype of the existing Slice node is reset to this slice subtype.
13100 -- Its bounds are obtained from its first index.
13104 -- For bit-packed slice subtypes, freeze immediately (except in the case
13105 -- of being in a "spec expression" where we never freeze when we first
13106 -- see the expression).
13111 -- For all other cases insert an itype reference in the slice's actions
13112 -- so that the itype is frozen at the proper place in the tree (i.e. at
13113 -- the point where actions for the slice are analyzed). Note that this
13114 -- is different from freezing the itype immediately, which might be
13115 -- premature (e.g. if the slice is within a transient scope). This needs
13116 -- to be done only if expansion is enabled.
13123 --------------------------------
13124 -- Set_String_Literal_Subtype --
13125 --------------------------------
13133 begin
13145 -- The low bound is set from the low bound of the corresponding index
13146 -- type. Note that we do not store the high bound in the string literal
13147 -- subtype, but it can be deduced if necessary from the length and the
13148 -- low bound.
13153 -- If the lower bound is not static we create a range for the string
13154 -- literal, using the index type and the known length of the literal.
13155 -- If the length is 1, then the upper bound is set to a mere copy of
13156 -- the lower bound; or else, if the index type is a signed integer,
13157 -- then the upper bound is computed as Low_Bound + L - 1; otherwise,
13158 -- the upper bound is computed as T'Val (T'Pos (Low_Bound) + L - 1).
13160 else
13161 declare
13171 begin
13176 High_Bound :=
13181 else
13182 High_Bound :=
13185 Prefix =>
13189 Left_Opnd =>
13192 Prefix =>
13194 Expressions =>
13196 Right_Opnd =>
13201 Set_String_Literal_Low_Bound
13204 else
13205 -- If the index type is an enumeration type, build bounds
13206 -- expression with attributes.
13208 Set_String_Literal_Low_Bound
13212 Prefix =>
13216 Analyze_And_Resolve
13219 -- Build bona fide subtype for the string, and wrap it in an
13220 -- unchecked conversion, because the back end expects the
13221 -- String_Literal_Subtype to have a static lower bound.
13223 Index_Subtype :=
13230 -- In this context, the Index_Type may already have a constraint,
13231 -- so use common base type on string subtype. The base type may
13232 -- be used when generating attributes of the string, for example
13233 -- in the context of a slice assignment.
13255 ------------------------------
13256 -- Simplify_Type_Conversion --
13257 ------------------------------
13260 begin
13262 declare
13267 begin
13268 -- Special processing if the conversion is the expression of a
13269 -- Rounding or Truncation attribute reference. In this case we
13270 -- replace:
13272 -- ityp (ftyp'Rounding (x)) or ityp (ftyp'Truncation (x))
13274 -- by
13276 -- ityp (x)
13278 -- with the Float_Truncate flag set to False or True respectively,
13279 -- which is more efficient. We reuse Rounding for Machine_Rounding
13280 -- as System.Fat_Gen, which is a permissible behavior.
13283 and then
13289 | Name_Machine_Rounding
13290 | Name_Truncation
13291 then
13292 declare
13295 begin
13301 -- Special processing for the conversion of an integer literal to
13302 -- a dynamic type: we first convert the literal to the root type
13303 -- and then convert the result to the target type, the goal being
13304 -- to avoid doing range checks in universal integer.
13310 then
13314 -- If the expression is a conversion to universal integer of an
13315 -- an expression with an integer type, then we can eliminate the
13316 -- intermediate conversion to universal integer.
13321 then
13329 ------------------------------
13330 -- Try_User_Defined_Literal --
13331 ------------------------------
13333 function Try_User_Defined_Literal
13336 is
13337 begin
13342 -- Both dependent expressions must have the same type as the context
13344 declare
13349 begin
13363 -- All dependent expressions must have the same type as the context
13365 declare
13368 begin
13373 then
13374 declare
13377 begin
13401 -------------------------------------------
13402 -- Try_User_Defined_Literal_For_Operator --
13403 -------------------------------------------
13405 function Try_User_Defined_Literal_For_Operator
13408 is
13409 begin
13411 | N_Op_Divide
13412 | N_Op_Mod
13413 | N_Op_Multiply
13414 | N_Op_Rem
13415 | N_Op_Subtract
13416 then
13417 -- Both operands must have the same type as the context
13418 -- (ignoring for now fixed-point and exponentiation ops).
13423 then
13431 then
13438 -- For other binary operators the context does not impose a type on
13439 -- the operands, but their types must match.
13442 not in N_Integer_Literal | N_String_Literal | N_Real_Literal
13443 and then
13444 Has_Applicable_User_Defined_Literal
13446 then
13451 not in N_Integer_Literal | N_String_Literal | N_Real_Literal
13452 and then
13453 Has_Applicable_User_Defined_Literal
13455 then
13462 then
13470 -----------------------------
13471 -- Unique_Fixed_Point_Type --
13472 -----------------------------
13476 -- Give error messages for true ambiguity. Messages are posted on node
13477 -- N, and entities T1, T2 are the possible interpretations.
13479 -----------------------
13480 -- Fixed_Point_Error --
13481 -----------------------
13484 begin
13490 -- Local variables
13498 -- Start of processing for Unique_Fixed_Point_Type
13500 begin
13501 -- The operations on Duration are visible, so Duration is always a
13502 -- possible interpretation.
13506 -- Look for fixed-point types in enclosing scopes
13515 then
13519 else
13530 -- Look for visible fixed type declarations in the context
13541 then
13545 else
13560 else
13561 -- When the context is a type conversion, issue the warning on the
13562 -- expression of the conversion because it is the actual operation.
13566 else
13570 Error_Msg_NE
13577 ----------------------
13578 -- Valid_Conversion --
13579 ----------------------
13581 function Valid_Conversion
13586 is
13591 function Conversion_Check
13594 -- Little routine to post Msg if Valid is False, returns Valid value
13597 -- If Report_Errs, then calls Errout.Error_Msg_N with its arguments
13599 procedure Conversion_Error_NE
13603 -- If Report_Errs, then calls Errout.Error_Msg_NE with its arguments
13606 -- Return True if expression is within an instance but is not in one of
13607 -- the actuals of the instantiation. Type conversions within an instance
13608 -- are not rechecked because type visibility may lead to spurious errors
13609 -- but conversions in an actual for a formal object must be checked.
13611 function Is_Discrim_Of_Bad_Access_Conversion_Argument
13613 -- Implicit anonymous-to-named access type conversions are not allowed
13614 -- if the "statically deeper than" relationship does not apply to the
13615 -- type of the conversion operand. See RM 8.6(28.1) and AARM 8.6(28.d).
13616 -- We deal with most such cases elsewhere so that we can emit more
13617 -- specific error messages (e.g., if the operand is an access parameter
13618 -- or a saooaaat (stand-alone object of an anonymous access type)), but
13619 -- here is where we catch the case where the operand is an access
13620 -- discriminant selected from a dereference of another such "bad"
13621 -- conversion argument.
13623 function Valid_Tagged_Conversion
13626 -- Specifically test for validity of tagged conversions
13629 -- Check index and component conformance, and accessibility levels if
13630 -- the component types are anonymous access types (Ada 2005).
13632 ----------------------
13633 -- Conversion_Check --
13634 ----------------------
13636 function Conversion_Check
13639 is
13640 begin
13641 if not Valid
13643 -- A generic unit has already been analyzed and we have verified
13644 -- that a particular conversion is OK in that context. Since the
13645 -- instance is reanalyzed without relying on the relationships
13646 -- established during the analysis of the generic, it is possible
13647 -- to end up with inconsistent views of private types. Do not emit
13648 -- the error message in such cases. The rest of the machinery in
13649 -- Valid_Conversion still ensures the proper compatibility of
13650 -- target and operand types.
13652 and then not In_Instance_Code
13653 then
13660 ------------------------
13661 -- Conversion_Error_N --
13662 ------------------------
13665 begin
13671 -------------------------
13672 -- Conversion_Error_NE --
13673 -------------------------
13675 procedure Conversion_Error_NE
13679 is
13680 begin
13686 ----------------------
13687 -- In_Instance_Code --
13688 ----------------------
13693 begin
13697 else
13701 -- The expression is part of an actual object if it appears in
13702 -- the generated object declaration in the instance.
13706 then
13709 else
13710 exit when
13719 -- Otherwise the expression appears within the instantiated unit
13725 --------------------------------------------------
13726 -- Is_Discrim_Of_Bad_Access_Conversion_Argument --
13727 --------------------------------------------------
13729 function Is_Discrim_Of_Bad_Access_Conversion_Argument
13731 is
13737 begin
13749 -- return False if Expr not of form <prefix>.all.Some_Component
13753 then
13754 -- conditional expressions, declare expressions ???
13761 -- The "statically deeper relationship" does not apply
13762 -- to generic formal access types, so a prefix of such
13763 -- a type is a "bad" prefix.
13768 -- The "statically deeper relationship" does apply to
13769 -- any other named access type.
13778 -- The "statically deeper relationship" applies to some
13779 -- anonymous access types and not to others. Return
13780 -- True for the cases where it does not apply. Also check
13781 -- recursively for the
13782 -- <prefix>.all.Access_Discrim.all.Access_Discrim case,
13783 -- where the correct result depends on <prefix>.
13786 N_Procedure_Specification | -- access parameter
13787 N_Function_Specification | -- access parameter
13788 N_Object_Declaration -- saooaaat
13792 ----------------------------
13793 -- Valid_Array_Conversion --
13794 ----------------------------
13811 begin
13812 -- Error if wrong number of dimensions
13814 if
13816 then
13817 Conversion_Error_N
13821 -- Number of dimensions matches
13823 else
13824 -- Loop through indexes of the two arrays
13832 -- Error if index types are incompatible
13838 then
13839 Conversion_Error_N
13841 Operand);
13849 -- If component types have same base type, all set
13854 -- Here if base types of components are not the same. The only
13855 -- time this is allowed is if we have anonymous access types.
13857 -- The conversion of arrays of anonymous access types can lead
13858 -- to dangling pointers. AI-392 formalizes the accessibility
13859 -- checks that must be applied to such conversions to prevent
13860 -- out-of-scope references.
13863 E_Anonymous_Access_Type
13864 | E_Anonymous_Access_Subprogram_Type
13866 and then
13868 then
13871 then
13874 Conversion_Error_N
13884 -- Conversion not allowed because of accessibility levels
13886 else
13887 Conversion_Error_N
13893 else
13897 -- All other cases where component base types do not match
13899 else
13900 Conversion_Error_N
13902 Operand);
13906 -- Check that component subtypes statically match. For numeric
13907 -- types this means that both must be either constrained or
13908 -- unconstrained. For enumeration types the bounds must match.
13909 -- All of this is checked in Subtypes_Statically_Match.
13911 if not Subtypes_Statically_Match
13913 then
13914 Conversion_Error_N
13923 -----------------------------
13924 -- Valid_Tagged_Conversion --
13925 -----------------------------
13927 function Valid_Tagged_Conversion
13930 is
13931 begin
13932 -- Upward conversions are allowed (RM 4.6(22))
13936 then
13939 -- Downward conversion are allowed if the operand is class-wide
13940 -- (RM 4.6(23)).
13944 then
13949 then
13950 return
13954 -- Ada 2005 (AI-251): A conversion is valid if the operand and target
13955 -- types are both class-wide types and the specific type associated
13956 -- with at least one of them is an interface type (RM 4.6 (23.1/2));
13957 -- at run-time a check will verify the validity of this interface
13958 -- type conversion.
13964 then
13967 -- Report errors
13972 and then not Interface_Present_In_Ancestor
13975 then
13978 Conversion_Error_N
13986 and then not Interface_Present_In_Ancestor
13989 then
13992 Conversion_Error_N
13996 -- Search for interface types shared between the target type and
13997 -- the operand interface type to complete the text of the error
13998 -- since the source of this error is a missing type conversion
13999 -- to such interface type.
14002 declare
14009 begin
14011 Target_Ifaces_List);
14013 Operand_Ifaces_List);
14021 then
14022 Error_Msg_Name_1 :=
14027 Conversion_Error_N
14030 else
14031 Conversion_Error_N
14049 then
14050 Conversion_Error_N
14052 Conversion_Error_N
14058 then
14059 Conversion_Error_N
14064 else
14065 Conversion_Error_NE
14072 -- Start of processing for Valid_Conversion
14074 begin
14078 declare
14086 begin
14087 -- Remove procedure calls, which syntactically cannot appear in
14088 -- this context, but which cannot be removed by type checking,
14089 -- because the context does not impose a type.
14091 -- The node may be labelled overloaded, but still contain only one
14092 -- interpretation because others were discarded earlier. If this
14093 -- is the case, retain the single interpretation if legal.
14101 then
14102 -- More than one candidate interpretation is available
14110 -- When compiling for a system where Address is of a visible
14111 -- integer type, spurious ambiguities can be produced when
14112 -- arithmetic operations have a literal operand and return
14113 -- System.Address or a descendant of it. These ambiguities
14114 -- are usually resolved by the context, but for conversions
14115 -- there is no context type and the removal of the spurious
14116 -- operations must be done explicitly here.
14118 if not Address_Is_Private
14120 then
14145 Conversion_Error_N
14148 -- If the interpretation involves a standard operator, use
14149 -- the location of the type, which may be user-defined.
14153 else
14157 Conversion_Error_N -- CODEFIX
14162 else
14166 Conversion_Error_N -- CODEFIX
14178 -- Deal with conversion of integer type to address if the pragma
14179 -- Allow_Integer_Address is in effect. We convert the conversion to
14180 -- an unchecked conversion in this case and we are all done.
14188 -- If we are within a child unit, check whether the type of the
14189 -- expression has an ancestor in a parent unit, in which case it
14190 -- belongs to its derivation class even if the ancestor is private.
14191 -- See RM 7.3.1 (5.2/3).
14195 -- Numeric types
14199 -- A universal fixed expression can be converted to any numeric type
14204 -- Also no need to check when in an instance or inlined body, because
14205 -- the legality has been established when the template was analyzed.
14206 -- Furthermore, numeric conversions may occur where only a private
14207 -- view of the operand type is visible at the instantiation point.
14208 -- This results in a spurious error if we check that the operand type
14209 -- is a numeric type.
14211 -- Note: in a previous version of this unit, the following tests were
14212 -- applied only for generated code (Comes_From_Source set to False),
14213 -- but in fact the test is required for source code as well, since
14214 -- this situation can arise in source code.
14219 -- Otherwise we need the conversion check
14221 else
14222 return Conversion_Check
14224 or else
14230 -- Array types
14236 then
14237 Conversion_Error_N
14241 else
14245 -- Ada 2005 (AI-251): Internally generated conversions of access to
14246 -- interface types added to force the displacement of the pointer to
14247 -- reference the corresponding dispatch table.
14252 then
14255 -- Ada 2005 (AI-251): Anonymous access types where target references an
14256 -- interface type.
14260 E_General_Access_Type | E_Anonymous_Access_Type
14262 then
14263 -- Check the static accessibility rule of 4.6(17). Note that the
14264 -- check is not enforced when within an instance body, since the
14265 -- RM requires such cases to be caught at run time.
14267 -- If the operand is a rewriting of an allocator no check is needed
14268 -- because there are no accessibility issues.
14276 then
14277 -- In an instance, this is a run-time check, but one we know
14278 -- will fail, so generate an appropriate warning. The raise
14279 -- will be generated by Expand_N_Type_Conversion.
14283 Conversion_Error_N
14285 Operand);
14288 else
14289 Conversion_Error_N
14291 Operand);
14295 -- Special accessibility checks are needed in the case of access
14296 -- discriminants declared for a limited type.
14300 then
14301 -- When the operand is a selected access discriminant the check
14302 -- needs to be made against the level of the object denoted by
14303 -- the prefix of the selected name (Accessibility_Level handles
14304 -- checking the prefix of the operand for this case).
14307 and then Static_Accessibility_Level
14310 then
14311 -- In an instance, this is a run-time check, but one we know
14312 -- will fail, so generate an appropriate warning. The raise
14313 -- will be generated by Expand_N_Type_Conversion.
14317 Conversion_Error_N
14322 -- Real error if not in instance body
14324 else
14325 Conversion_Error_N
14332 -- The case of a reference to an access discriminant from
14333 -- within a limited type declaration (which will appear as
14334 -- a discriminal) is always illegal because the level of the
14335 -- discriminant is considered to be deeper than any (nameable)
14336 -- access type.
14340 and then
14343 then
14344 Conversion_Error_N
14346 Operand);
14354 -- General and anonymous access types
14357 E_General_Access_Type | E_Anonymous_Access_Type
14358 and then
14359 Conversion_Check
14361 and then
14363 E_Access_Subprogram_Type |
14364 E_Access_Protected_Subprogram_Type,
14366 then
14369 then
14370 Conversion_Error_N
14375 -- Check the static accessibility rule of 4.6(17). Note that the
14376 -- check is not enforced when within an instance body, since the RM
14377 -- requires such cases to be caught at run time.
14382 N_Object_Declaration
14383 then
14384 -- Ada 2012 (AI05-0149): Perform legality checking on implicit
14385 -- conversions from an anonymous access type to a named general
14386 -- access type. Such conversions are not allowed in the case of
14387 -- access parameters and stand-alone objects of an anonymous
14388 -- access type. The implicit conversion case is recognized by
14389 -- testing that Comes_From_Source is False and that it's been
14390 -- rewritten. The Comes_From_Source test isn't sufficient because
14391 -- nodes in inlined calls to predefined library routines can have
14392 -- Comes_From_Source set to False. (Is there a better way to test
14393 -- for implicit conversions???).
14394 --
14395 -- Do not treat a rewritten 'Old attribute reference like other
14396 -- rewrite substitutions. This makes a difference, for example,
14397 -- in the case where we are generating the expansion of a
14398 -- membership test of the form
14399 -- Saooaaat'Old in Named_Access_Type
14400 -- because in this case Valid_Conversion needs to return True
14401 -- (otherwise the expansion will be False - see the call site
14402 -- in exp_ch4.adb).
14410 then
14413 -- When applying restriction No_Dynamic_Accessibility_Check,
14414 -- implicit conversions are allowed when the operand type is
14415 -- not deeper than the target type.
14420 then
14421 Conversion_Error_N
14425 -- Implicit conversions aren't allowed for objects of an
14426 -- anonymous access type, since such objects have nonstatic
14427 -- levels in Ada 2012.
14430 = N_Object_Declaration
14431 then
14432 Conversion_Error_N
14437 -- Implicit conversions aren't allowed for anonymous access
14438 -- parameters. We exclude anonymous access results as well
14439 -- as universal_access "=".
14443 N_Function_Specification |
14444 N_Procedure_Specification
14446 then
14447 Conversion_Error_N
14452 -- Detect access discriminant values that are illegal
14453 -- implicit anonymous-to-named access conversion operands.
14456 then
14457 Conversion_Error_N
14462 -- In other cases, the level of the operand's type must be
14463 -- statically less deep than that of the target type, else
14464 -- implicit conversion is disallowed (by RM12-8.6(27.1/3)).
14468 then
14469 Conversion_Error_N
14476 -- Check if the operand is deeper than the target type, taking
14477 -- care to avoid the case where we are converting a result of a
14478 -- function returning an anonymous access type since the "master
14479 -- of the call" would be target type of the conversion unless
14480 -- the target type is anonymous access as well - see RM 3.10.2
14481 -- (10.3/3).
14483 -- Note that when the restriction No_Dynamic_Accessibility_Checks
14484 -- is in effect wei also want to proceed with the conversion check
14485 -- described above.
14490 /= N_Function_Specification
14494 -- Check we are not in a return value ???
14497 or else
14500 then
14501 -- In an instance, this is a run-time check, but one we know
14502 -- will fail, so generate an appropriate warning. The raise
14503 -- will be generated by Expand_N_Type_Conversion.
14507 Conversion_Error_N
14509 Operand);
14512 -- If not in an instance body, this is a real error
14514 else
14515 -- Avoid generation of spurious error message
14518 Conversion_Error_N
14520 Operand);
14526 -- Special accessibility checks are needed in the case of access
14527 -- discriminants declared for a limited type.
14531 then
14532 -- When the operand is a selected access discriminant the check
14533 -- needs to be made against the level of the object denoted by
14534 -- the prefix of the selected name (Accessibility_Level handles
14535 -- checking the prefix of the operand for this case).
14538 and then Static_Accessibility_Level
14541 then
14542 -- In an instance, this is a run-time check, but one we know
14543 -- will fail, so generate an appropriate warning. The raise
14544 -- will be generated by Expand_N_Type_Conversion.
14548 Conversion_Error_N
14553 -- If not in an instance body, this is a real error
14555 else
14556 Conversion_Error_N
14563 -- The case of a reference to an access discriminant from
14564 -- within a limited type declaration (which will appear as
14565 -- a discriminal) is always illegal because the level of the
14566 -- discriminant is considered to be deeper than any (nameable)
14567 -- access type.
14570 and then
14573 then
14574 Conversion_Error_N
14576 Operand);
14582 -- In the presence of limited_with clauses we have to use nonlimited
14583 -- views, if available.
14587 -- Helper function to handle limited views
14589 --------------------------
14590 -- Full_Designated_Type --
14591 --------------------------
14596 begin
14597 -- Handle the limited view of a type
14601 then
14603 else
14608 -- Local Declarations
14616 -- Start of processing for Check_Limited
14618 begin
14622 else
14624 Conversion_Error_NE
14629 -- Ada 2005 AI-384: legality rule is symmetric in both
14630 -- designated types. The conversion is legal (with possible
14631 -- constraint check) if either designated type is
14632 -- unconstrained.
14635 or else
14637 and then
14640 then
14641 -- Special case, if Value_Size has been used to make the
14642 -- sizes different, the conversion is not allowed even
14643 -- though the subtypes statically match.
14648 then
14649 Conversion_Error_NE
14652 Conversion_Error_NE
14657 -- Normal case where conversion is allowed
14659 else
14663 else
14664 Error_Msg_NE
14672 -- Access to subprogram types. If the operand is an access parameter,
14673 -- the type has a deeper accessibility that any master, and cannot be
14674 -- assigned. We must make an exception if the conversion is part of an
14675 -- assignment and the target is the return object of an extended return
14676 -- statement, because in that case the accessibility check takes place
14677 -- after the return.
14681 -- Note: this test of Opnd_Type is there to prevent entering this
14682 -- branch in the case of a remote access to subprogram type, which
14683 -- is internally represented as an E_Record_Type.
14686 then
14690 and then
14694 then
14695 Conversion_Error_N
14697 Operand);
14698 Conversion_Error_N
14701 Operand);
14703 Error_Msg_NE
14708 -- Check that the designated types are subtype conformant
14714 -- Check the static accessibility rule of 4.6(20)
14718 then
14719 Conversion_Error_N
14721 Operand);
14723 -- Check that if the operand type is declared in a generic body,
14724 -- then the target type must be declared within that same body
14725 -- (enforces last sentence of 4.6(20)).
14728 declare
14734 begin
14741 Conversion_Error_N
14748 -- Check that the strub modes are compatible.
14749 -- We wish to reject explicit conversions only for
14750 -- incompatible modes.
14752 return Conversion_Check
14753 (Compatible_Strub_Modes
14758 -- Remote access to subprogram types
14762 then
14763 -- It is valid to convert from one RAS type to another provided
14764 -- that their specification statically match.
14766 -- Note: at this point, remote access to subprogram types have been
14767 -- expanded to their E_Record_Type representation, and we need to
14768 -- go back to the original access type definition using the
14769 -- Corresponding_Remote_Type attribute in order to check that the
14770 -- designated profiles match.
14775 Check_Subtype_Conformant
14778 Old_Id =>
14780 Err_Loc =>
14781 N);
14783 -- Check that the strub modes are compatible.
14784 -- We wish to reject explicit conversions only for
14785 -- incompatible modes.
14787 return Conversion_Check
14788 (Compatible_Strub_Modes
14793 -- If it was legal in the generic, it's legal in the instance
14798 -- If both are tagged types, check legality of view conversions
14801 and then
14803 then
14806 -- Types derived from the same root type are convertible
14811 -- In an instance or an inlined body, there may be inconsistent views of
14812 -- the same type, or of types derived from a common root.
14815 and then
14818 then
14821 -- Special check for common access type error case
14825 then
14827 Conversion_Error_NE -- CODEFIX
14831 -- Here we have a real conversion error
14833 else
14834 -- Check for missing regular with_clause when only a limited view of
14835 -- target is available.
14838 Conversion_Error_NE
14841 Conversion_Error_NE
14846 and then In_Package_Body
14847 then
14848 Conversion_Error_NE
14850 Conversion_Error_NE
14854 else
14855 Conversion_Error_NE