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------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- S E M _ R E S --
-- --
-- B o d y --
-- --
-- $Revision$
-- --
-- Copyright (C) 1992-2001, Free Software Foundation, Inc. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- ware Foundation; either version 2, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
-- for more details. You should have received a copy of the GNU General --
-- Public License distributed with GNAT; see file COPYING. If not, write --
-- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
-- MA 02111-1307, USA. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
-- --
------------------------------------------------------------------------------
with Atree; use Atree;
with Checks; use Checks;
with Debug; use Debug;
with Debug_A; use Debug_A;
with Einfo; use Einfo;
with Errout; use Errout;
with Expander; use Expander;
with Exp_Ch7; use Exp_Ch7;
with Exp_Util; use Exp_Util;
with Freeze; use Freeze;
with Itypes; use Itypes;
with Lib; use Lib;
with Lib.Xref; use Lib.Xref;
with Namet; use Namet;
with Nmake; use Nmake;
with Nlists; use Nlists;
with Opt; use Opt;
with Output; use Output;
with Restrict; use Restrict;
with Rtsfind; use Rtsfind;
with Sem; use Sem;
with Sem_Aggr; use Sem_Aggr;
with Sem_Attr; use Sem_Attr;
with Sem_Cat; use Sem_Cat;
with Sem_Ch4; use Sem_Ch4;
with Sem_Ch6; use Sem_Ch6;
with Sem_Ch8; use Sem_Ch8;
with Sem_Disp; use Sem_Disp;
with Sem_Dist; use Sem_Dist;
with Sem_Elab; use Sem_Elab;
with Sem_Eval; use Sem_Eval;
with Sem_Intr; use Sem_Intr;
with Sem_Util; use Sem_Util;
with Sem_Type; use Sem_Type;
with Sem_Warn; use Sem_Warn;
with Sinfo; use Sinfo;
with Stand; use Stand;
with Stringt; use Stringt;
with Targparm; use Targparm;
with Tbuild; use Tbuild;
with Uintp; use Uintp;
with Urealp; use Urealp;
package body Sem_Res is
-----------------------
-- Local Subprograms --
-----------------------
-- Second pass (top-down) type checking and overload resolution procedures
-- Typ is the type required by context. These procedures propagate the
-- type information recursively to the descendants of N. If the node
-- is not overloaded, its Etype is established in the first pass. If
-- overloaded, the Resolve routines set the correct type. For arith.
-- operators, the Etype is the base type of the context.
-- Note that Resolve_Attribute is separated off in Sem_Attr
procedure Ambiguous_Character (C : Node_Id);
-- Give list of candidate interpretations when a character literal cannot
-- be resolved.
procedure Check_Discriminant_Use (N : Node_Id);
-- Enforce the restrictions on the use of discriminants when constraining
-- a component of a discriminated type (record or concurrent type).
procedure Check_For_Visible_Operator (N : Node_Id; T : Entity_Id);
-- Given a node for an operator associated with type T, check that
-- the operator is visible. Operators all of whose operands are
-- universal must be checked for visibility during resolution
-- because their type is not determinable based on their operands.
function Check_Infinite_Recursion (N : Node_Id) return Boolean;
-- Given a call node, N, which is known to occur immediately within the
-- subprogram being called, determines whether it is a detectable case of
-- an infinite recursion, and if so, outputs appropriate messages. Returns
-- True if an infinite recursion is detected, and False otherwise.
procedure Check_Initialization_Call (N : Entity_Id; Nam : Entity_Id);
-- If the type of the object being initialized uses the secondary stack
-- directly or indirectly, create a transient scope for the call to the
-- Init_Proc. This is because we do not create transient scopes for the
-- initialization of individual components within the init_proc itself.
-- Could be optimized away perhaps?
function Is_Predefined_Op (Nam : Entity_Id) return Boolean;
-- Utility to check whether the name in the call is a predefined
-- operator, in which case the call is made into an operator node.
-- An instance of an intrinsic conversion operation may be given
-- an operator name, but is not treated like an operator.
procedure Replace_Actual_Discriminants (N : Node_Id; Default : Node_Id);
-- If a default expression in entry call N depends on the discriminants
-- of the task, it must be replaced with a reference to the discriminant
-- of the task being called.
procedure Resolve_Allocator (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Arithmetic_Op (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Call (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Character_Literal (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Comparison_Op (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Conditional_Expression (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Equality_Op (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Explicit_Dereference (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Entity_Name (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Indexed_Component (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Integer_Literal (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Logical_Op (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Membership_Op (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Null (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Operator_Symbol (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Op_Concat (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Op_Expon (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Op_Not (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Qualified_Expression (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Range (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Real_Literal (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Reference (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Selected_Component (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Shift (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Short_Circuit (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Slice (N : Node_Id; Typ : Entity_Id);
procedure Resolve_String_Literal (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Subprogram_Info (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Type_Conversion (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Unary_Op (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Unchecked_Expression (N : Node_Id; Typ : Entity_Id);
procedure Resolve_Unchecked_Type_Conversion (N : Node_Id; Typ : Entity_Id);
function Operator_Kind
(Op_Name : Name_Id;
Is_Binary : Boolean)
return Node_Kind;
-- Utility to map the name of an operator into the corresponding Node. Used
-- by other node rewriting procedures.
procedure Resolve_Actuals (N : Node_Id; Nam : Entity_Id);
-- Resolve actuals of call, and add default expressions for missing ones.
procedure Resolve_Entry_Call (N : Node_Id; Typ : Entity_Id);
-- Called from Resolve_Call, when the prefix denotes an entry or element
-- of entry family. Actuals are resolved as for subprograms, and the node
-- is rebuilt as an entry call. Also called for protected operations. Typ
-- is the context type, which is used when the operation is a protected
-- function with no arguments, and the return value is indexed.
procedure Resolve_Intrinsic_Operator (N : Node_Id; Typ : Entity_Id);
-- A call to a user-defined intrinsic operator is rewritten as a call
-- to the corresponding predefined operator, with suitable conversions.
procedure Rewrite_Operator_As_Call (N : Node_Id; Nam : Entity_Id);
-- If an operator node resolves to a call to a user-defined operator,
-- rewrite the node as a function call.
procedure Make_Call_Into_Operator
(N : Node_Id;
Typ : Entity_Id;
Op_Id : Entity_Id);
-- Inverse transformation: if an operator is given in functional notation,
-- then after resolving the node, transform into an operator node, so
-- that operands are resolved properly. Recall that predefined operators
-- do not have a full signature and special resolution rules apply.
procedure Rewrite_Renamed_Operator (N : Node_Id; Op : Entity_Id);
-- An operator can rename another, e.g. in an instantiation. In that
-- case, the proper operator node must be constructed.
procedure Set_String_Literal_Subtype (N : Node_Id; Typ : Entity_Id);
-- The String_Literal_Subtype is built for all strings that are not
-- operands of a static concatenation operation. If the argument is not
-- a String the function is a no-op.
procedure Set_Slice_Subtype (N : Node_Id);
-- Build subtype of array type, with the range specified by the slice.
function Unique_Fixed_Point_Type (N : Node_Id) return Entity_Id;
-- A universal_fixed expression in an universal context is unambiguous if
-- there is only one applicable fixed point type. Determining whether
-- there is only one requires a search over all visible entities, and
-- happens only in very pathological cases (see 6115-006).
function Valid_Conversion
(N : Node_Id;
Target : Entity_Id;
Operand : Node_Id)
return Boolean;
-- Verify legality rules given in 4.6 (8-23). Target is the target
-- type of the conversion, which may be an implicit conversion of
-- an actual parameter to an anonymous access type (in which case
-- N denotes the actual parameter and N = Operand).
-------------------------
-- Ambiguous_Character --
-------------------------
procedure Ambiguous_Character (C : Node_Id) is
E : Entity_Id;
begin
if Nkind (C) = N_Character_Literal then
Error_Msg_N ("ambiguous character literal", C);
Error_Msg_N
("\possible interpretations: Character, Wide_Character!", C);
E := Current_Entity (C);
if Present (E) then
while Present (E) loop
Error_Msg_NE ("\possible interpretation:}!", C, Etype (E));
E := Homonym (E);
end loop;
end if;
end if;
end Ambiguous_Character;
-------------------------
-- Analyze_And_Resolve --
-------------------------
procedure Analyze_And_Resolve (N : Node_Id) is
begin
Analyze (N);
Resolve (N, Etype (N));
end Analyze_And_Resolve;
procedure Analyze_And_Resolve (N : Node_Id; Typ : Entity_Id) is
begin
Analyze (N);
Resolve (N, Typ);
end Analyze_And_Resolve;
-- Version withs check(s) suppressed
procedure Analyze_And_Resolve
(N : Node_Id;
Typ : Entity_Id;
Suppress : Check_Id)
is
Scop : Entity_Id := Current_Scope;
begin
if Suppress = All_Checks then
declare
Svg : constant Suppress_Record := Scope_Suppress;
begin
Scope_Suppress := (others => True);
Analyze_And_Resolve (N, Typ);
Scope_Suppress := Svg;
end;
else
declare
Svg : constant Boolean := Get_Scope_Suppress (Suppress);
begin
Set_Scope_Suppress (Suppress, True);
Analyze_And_Resolve (N, Typ);
Set_Scope_Suppress (Suppress, Svg);
end;
end if;
if Current_Scope /= Scop
and then Scope_Is_Transient
then
-- This can only happen if a transient scope was created
-- for an inner expression, which will be removed upon
-- completion of the analysis of an enclosing construct.
-- The transient scope must have the suppress status of
-- the enclosing environment, not of this Analyze call.
Scope_Stack.Table (Scope_Stack.Last).Save_Scope_Suppress :=
Scope_Suppress;
end if;
end Analyze_And_Resolve;
procedure Analyze_And_Resolve
(N : Node_Id;
Suppress : Check_Id)
is
Scop : Entity_Id := Current_Scope;
begin
if Suppress = All_Checks then
declare
Svg : constant Suppress_Record := Scope_Suppress;
begin
Scope_Suppress := (others => True);
Analyze_And_Resolve (N);
Scope_Suppress := Svg;
end;
else
declare
Svg : constant Boolean := Get_Scope_Suppress (Suppress);
begin
Set_Scope_Suppress (Suppress, True);
Analyze_And_Resolve (N);
Set_Scope_Suppress (Suppress, Svg);
end;
end if;
if Current_Scope /= Scop
and then Scope_Is_Transient
then
Scope_Stack.Table (Scope_Stack.Last).Save_Scope_Suppress :=
Scope_Suppress;
end if;
end Analyze_And_Resolve;
----------------------------
-- Check_Discriminant_Use --
----------------------------
procedure Check_Discriminant_Use (N : Node_Id) is
PN : constant Node_Id := Parent (N);
Disc : constant Entity_Id := Entity (N);
P : Node_Id;
D : Node_Id;
begin
-- Any use in a default expression is legal.
if In_Default_Expression then
null;
elsif Nkind (PN) = N_Range then
-- Discriminant cannot be used to constrain a scalar type.
P := Parent (PN);
if Nkind (P) = N_Range_Constraint
and then Nkind (Parent (P)) = N_Subtype_Indication
and then Nkind (Parent (Parent (P))) = N_Component_Declaration
then
Error_Msg_N ("discriminant cannot constrain scalar type", N);
elsif Nkind (P) = N_Index_Or_Discriminant_Constraint then
-- The following check catches the unusual case where
-- a discriminant appears within an index constraint
-- that is part of a larger expression within a constraint
-- on a component, e.g. "C : Int range 1 .. F (new A(1 .. D))".
-- For now we only check case of record components, and
-- note that a similar check should also apply in the
-- case of discriminant constraints below. ???
-- Note that the check for N_Subtype_Declaration below is to
-- detect the valid use of discriminants in the constraints of a
-- subtype declaration when this subtype declaration appears
-- inside the scope of a record type (which is syntactically
-- illegal, but which may be created as part of derived type
-- processing for records). See Sem_Ch3.Build_Derived_Record_Type
-- for more info.
if Ekind (Current_Scope) = E_Record_Type
and then Scope (Disc) = Current_Scope
and then not
(Nkind (Parent (P)) = N_Subtype_Indication
and then
(Nkind (Parent (Parent (P))) = N_Component_Declaration
or else Nkind (Parent (Parent (P))) = N_Subtype_Declaration)
and then Paren_Count (N) = 0)
then
Error_Msg_N
("discriminant must appear alone in component constraint", N);
return;
end if;
-- Detect a common beginner error:
-- type R (D : Positive := 100) is record
-- Name: String (1 .. D);
-- end record;
-- The default value causes an object of type R to be
-- allocated with room for Positive'Last characters.
declare
SI : Node_Id;
T : Entity_Id;
TB : Node_Id;
CB : Entity_Id;
function Large_Storage_Type (T : Entity_Id) return Boolean;
-- Return True if type T has a large enough range that
-- any array whose index type covered the whole range of
-- the type would likely raise Storage_Error.
function Large_Storage_Type (T : Entity_Id) return Boolean is
begin
return
T = Standard_Integer
or else
T = Standard_Positive
or else
T = Standard_Natural;
end Large_Storage_Type;
begin
-- Check that the Disc has a large range
if not Large_Storage_Type (Etype (Disc)) then
goto No_Danger;
end if;
-- If the enclosing type is limited, we allocate only the
-- default value, not the maximum, and there is no need for
-- a warning.
if Is_Limited_Type (Scope (Disc)) then
goto No_Danger;
end if;
-- Check that it is the high bound
if N /= High_Bound (PN)
or else not Present (Discriminant_Default_Value (Disc))
then
goto No_Danger;
end if;
-- Check the array allows a large range at this bound.
-- First find the array
SI := Parent (P);
if Nkind (SI) /= N_Subtype_Indication then
goto No_Danger;
end if;
T := Entity (Subtype_Mark (SI));
if not Is_Array_Type (T) then
goto No_Danger;
end if;
-- Next, find the dimension
TB := First_Index (T);
CB := First (Constraints (P));
while True
and then Present (TB)
and then Present (CB)
and then CB /= PN
loop
Next_Index (TB);
Next (CB);
end loop;
if CB /= PN then
goto No_Danger;
end if;
-- Now, check the dimension has a large range
if not Large_Storage_Type (Etype (TB)) then
goto No_Danger;
end if;
-- Warn about the danger
Error_Msg_N
("creation of object of this type may raise Storage_Error?",
N);
<<No_Danger>>
null;
end;
end if;
-- Legal case is in index or discriminant constraint
elsif Nkind (PN) = N_Index_Or_Discriminant_Constraint
or else Nkind (PN) = N_Discriminant_Association
then
if Paren_Count (N) > 0 then
Error_Msg_N
("discriminant in constraint must appear alone", N);
end if;
return;
-- Otherwise, context is an expression. It should not be within
-- (i.e. a subexpression of) a constraint for a component.
else
D := PN;
P := Parent (PN);
while Nkind (P) /= N_Component_Declaration
and then Nkind (P) /= N_Subtype_Indication
and then Nkind (P) /= N_Entry_Declaration
loop
D := P;
P := Parent (P);
exit when No (P);
end loop;
-- If the discriminant is used in an expression that is a bound
-- of a scalar type, an Itype is created and the bounds are attached
-- to its range, not to the original subtype indication. Such use
-- is of course a double fault.
if (Nkind (P) = N_Subtype_Indication
and then
(Nkind (Parent (P)) = N_Component_Declaration
or else Nkind (Parent (P)) = N_Derived_Type_Definition)
and then D = Constraint (P))
-- The constraint itself may be given by a subtype indication,
-- rather than by a more common discrete range.
or else (Nkind (P) = N_Subtype_Indication
and then Nkind (Parent (P)) = N_Index_Or_Discriminant_Constraint)
or else Nkind (P) = N_Entry_Declaration
or else Nkind (D) = N_Defining_Identifier
then
Error_Msg_N
("discriminant in constraint must appear alone", N);
end if;
end if;
end Check_Discriminant_Use;
--------------------------------
-- Check_For_Visible_Operator --
--------------------------------
procedure Check_For_Visible_Operator (N : Node_Id; T : Entity_Id) is
Orig_Node : Node_Id := Original_Node (N);
begin
if Comes_From_Source (Orig_Node)
and then not In_Open_Scopes (Scope (T))
and then not Is_Potentially_Use_Visible (T)
and then not In_Use (T)
and then not In_Use (Scope (T))
and then (not Present (Entity (N))
or else Ekind (Entity (N)) /= E_Function)
and then (Nkind (Orig_Node) /= N_Function_Call
or else Nkind (Name (Orig_Node)) /= N_Expanded_Name
or else Entity (Prefix (Name (Orig_Node))) /= Scope (T))
and then not In_Instance
then
Error_Msg_NE
("operator for} is not directly visible!", N, First_Subtype (T));
Error_Msg_N ("use clause would make operation legal!", N);
end if;
end Check_For_Visible_Operator;
------------------------------
-- Check_Infinite_Recursion --
------------------------------
function Check_Infinite_Recursion (N : Node_Id) return Boolean is
P : Node_Id;
C : Node_Id;
begin
-- Loop moving up tree, quitting if something tells us we are
-- definitely not in an infinite recursion situation.
C := N;
loop
P := Parent (C);
exit when Nkind (P) = N_Subprogram_Body;
if Nkind (P) = N_Or_Else or else
Nkind (P) = N_And_Then or else
Nkind (P) = N_If_Statement or else
Nkind (P) = N_Case_Statement
then
return False;
elsif Nkind (P) = N_Handled_Sequence_Of_Statements
and then C /= First (Statements (P))
then
return False;
else
C := P;
end if;
end loop;
Warn_On_Instance := True;
Error_Msg_N ("possible infinite recursion?", N);
Error_Msg_N ("\Storage_Error may be raised at run time?", N);
Warn_On_Instance := False;
return True;
end Check_Infinite_Recursion;
-------------------------------
-- Check_Initialization_Call --
-------------------------------
procedure Check_Initialization_Call (N : Entity_Id; Nam : Entity_Id) is
Typ : Entity_Id := Etype (First_Formal (Nam));
function Uses_SS (T : Entity_Id) return Boolean;
function Uses_SS (T : Entity_Id) return Boolean is
Comp : Entity_Id;
Expr : Node_Id;
begin
if Is_Controlled (T)
or else Has_Controlled_Component (T)
or else Functions_Return_By_DSP_On_Target
then
return False;
elsif Is_Array_Type (T) then
return Uses_SS (Component_Type (T));
elsif Is_Record_Type (T) then
Comp := First_Component (T);
while Present (Comp) loop
if Ekind (Comp) = E_Component
and then Nkind (Parent (Comp)) = N_Component_Declaration
then
Expr := Expression (Parent (Comp));
if Nkind (Expr) = N_Function_Call
and then Requires_Transient_Scope (Etype (Expr))
then
return True;
elsif Uses_SS (Etype (Comp)) then
return True;
end if;
end if;
Next_Component (Comp);
end loop;
return False;
else
return False;
end if;
end Uses_SS;
begin
if Uses_SS (Typ) then
Establish_Transient_Scope (First_Actual (N), Sec_Stack => True);
end if;
end Check_Initialization_Call;
------------------------------
-- Check_Parameterless_Call --
------------------------------
procedure Check_Parameterless_Call (N : Node_Id) is
Nam : Node_Id;
begin
if Nkind (N) in N_Has_Etype and then Etype (N) = Any_Type then
return;
end if;
-- Rewrite as call if overloadable entity that is (or could be, in
-- the overloaded case) a function call. If we know for sure that
-- the entity is an enumeration literal, we do not rewrite it.
if (Is_Entity_Name (N)
and then Is_Overloadable (Entity (N))
and then (Ekind (Entity (N)) /= E_Enumeration_Literal
or else Is_Overloaded (N)))
-- Rewrite as call if it is an explicit deference of an expression of
-- a subprogram access type, and the suprogram type is not that of a
-- procedure or entry.
or else
(Nkind (N) = N_Explicit_Dereference
and then Ekind (Etype (N)) = E_Subprogram_Type
and then Base_Type (Etype (Etype (N))) /= Standard_Void_Type)
-- Rewrite as call if it is a selected component which is a function,
-- this is the case of a call to a protected function (which may be
-- overloaded with other protected operations).
or else
(Nkind (N) = N_Selected_Component
and then (Ekind (Entity (Selector_Name (N))) = E_Function
or else ((Ekind (Entity (Selector_Name (N))) = E_Entry
or else
Ekind (Entity (Selector_Name (N))) = E_Procedure)
and then Is_Overloaded (Selector_Name (N)))))
-- If one of the above three conditions is met, rewrite as call.
-- Apply the rewriting only once.
then
if Nkind (Parent (N)) /= N_Function_Call
or else N /= Name (Parent (N))
then
Nam := New_Copy (N);
-- If overloaded, overload set belongs to new copy.
Save_Interps (N, Nam);
-- Change node to parameterless function call (note that the
-- Parameter_Associations associations field is left set to Empty,
-- its normal default value since there are no parameters)
Change_Node (N, N_Function_Call);
Set_Name (N, Nam);
Set_Sloc (N, Sloc (Nam));
Analyze_Call (N);
end if;
elsif Nkind (N) = N_Parameter_Association then
Check_Parameterless_Call (Explicit_Actual_Parameter (N));
end if;
end Check_Parameterless_Call;
----------------------
-- Is_Predefined_Op --
----------------------
function Is_Predefined_Op (Nam : Entity_Id) return Boolean is
begin
return Is_Intrinsic_Subprogram (Nam)
and then not Is_Generic_Instance (Nam)
and then Chars (Nam) in Any_Operator_Name
and then (No (Alias (Nam))
or else Is_Predefined_Op (Alias (Nam)));
end Is_Predefined_Op;
-----------------------------
-- Make_Call_Into_Operator --
-----------------------------
procedure Make_Call_Into_Operator
(N : Node_Id;
Typ : Entity_Id;
Op_Id : Entity_Id)
is
Op_Name : constant Name_Id := Chars (Op_Id);
Act1 : Node_Id := First_Actual (N);
Act2 : Node_Id := Next_Actual (Act1);
Error : Boolean := False;
Is_Binary : constant Boolean := Present (Act2);
Op_Node : Node_Id;
Opnd_Type : Entity_Id;
Orig_Type : Entity_Id := Empty;
Pack : Entity_Id;
type Kind_Test is access function (E : Entity_Id) return Boolean;
function Is_Definite_Access_Type (E : Entity_Id) return Boolean;
-- Determine whether E is an access type declared by an access decla-
-- ration, and not an (anonymous) allocator type.
function Operand_Type_In_Scope (S : Entity_Id) return Boolean;
-- If the operand is not universal, and the operator is given by a
-- expanded name, verify that the operand has an interpretation with
-- a type defined in the given scope of the operator.
function Type_In_P (Test : Kind_Test) return Entity_Id;
-- Find a type of the given class in the package Pack that contains
-- the operator.
-----------------------------
-- Is_Definite_Access_Type --
-----------------------------
function Is_Definite_Access_Type (E : Entity_Id) return Boolean is
Btyp : constant Entity_Id := Base_Type (E);
begin
return Ekind (Btyp) = E_Access_Type
or else (Ekind (Btyp) = E_Access_Subprogram_Type
and then Comes_From_Source (Btyp));
end Is_Definite_Access_Type;
---------------------------
-- Operand_Type_In_Scope --
---------------------------
function Operand_Type_In_Scope (S : Entity_Id) return Boolean is
Nod : constant Node_Id := Right_Opnd (Op_Node);
I : Interp_Index;
It : Interp;
begin
if not Is_Overloaded (Nod) then
return Scope (Base_Type (Etype (Nod))) = S;
else
Get_First_Interp (Nod, I, It);
while Present (It.Typ) loop
if Scope (Base_Type (It.Typ)) = S then
return True;
end if;
Get_Next_Interp (I, It);
end loop;
return False;
end if;
end Operand_Type_In_Scope;
---------------
-- Type_In_P --
---------------
function Type_In_P (Test : Kind_Test) return Entity_Id is
E : Entity_Id;
function In_Decl return Boolean;
-- Verify that node is not part of the type declaration for the
-- candidate type, which would otherwise be invisible.
-------------
-- In_Decl --
-------------
function In_Decl return Boolean is
Decl_Node : constant Node_Id := Parent (E);
N2 : Node_Id;
begin
N2 := N;
if Etype (E) = Any_Type then
return True;
elsif No (Decl_Node) then
return False;
else
while Present (N2)
and then Nkind (N2) /= N_Compilation_Unit
loop
if N2 = Decl_Node then
return True;
else
N2 := Parent (N2);
end if;
end loop;
return False;
end if;
end In_Decl;
-- Start of processing for Type_In_P
begin
-- If the context type is declared in the prefix package, this
-- is the desired base type.
if Scope (Base_Type (Typ)) = Pack
and then Test (Typ)
then
return Base_Type (Typ);
else
E := First_Entity (Pack);
while Present (E) loop
if Test (E)
and then not In_Decl
then
return E;
end if;
Next_Entity (E);
end loop;
return Empty;
end if;
end Type_In_P;
---------------------------
-- Operand_Type_In_Scope --
---------------------------
-- Start of processing for Make_Call_Into_Operator
begin
Op_Node := New_Node (Operator_Kind (Op_Name, Is_Binary), Sloc (N));
-- Binary operator
if Is_Binary then
Set_Left_Opnd (Op_Node, Relocate_Node (Act1));
Set_Right_Opnd (Op_Node, Relocate_Node (Act2));
Save_Interps (Act1, Left_Opnd (Op_Node));
Save_Interps (Act2, Right_Opnd (Op_Node));
Act1 := Left_Opnd (Op_Node);
Act2 := Right_Opnd (Op_Node);
-- Unary operator
else
Set_Right_Opnd (Op_Node, Relocate_Node (Act1));
Save_Interps (Act1, Right_Opnd (Op_Node));
Act1 := Right_Opnd (Op_Node);
end if;
-- If the operator is denoted by an expanded name, and the prefix is
-- not Standard, but the operator is a predefined one whose scope is
-- Standard, then this is an implicit_operator, inserted as an
-- interpretation by the procedure of the same name. This procedure
-- overestimates the presence of implicit operators, because it does
-- not examine the type of the operands. Verify now that the operand
-- type appears in the given scope. If right operand is universal,
-- check the other operand. In the case of concatenation, either
-- argument can be the component type, so check the type of the result.
-- If both arguments are literals, look for a type of the right kind
-- defined in the given scope. This elaborate nonsense is brought to
-- you courtesy of b33302a. The type itself must be frozen, so we must
-- find the type of the proper class in the given scope.
-- A final wrinkle is the multiplication operator for fixed point
-- types, which is defined in Standard only, and not in the scope of
-- the fixed_point type itself.
if Nkind (Name (N)) = N_Expanded_Name then
Pack := Entity (Prefix (Name (N)));
-- If the entity being called is defined in the given package,
-- it is a renaming of a predefined operator, and known to be
-- legal.
if Scope (Entity (Name (N))) = Pack
and then Pack /= Standard_Standard
then
null;
elsif (Op_Name = Name_Op_Multiply
or else Op_Name = Name_Op_Divide)
and then Is_Fixed_Point_Type (Etype (Left_Opnd (Op_Node)))
and then Is_Fixed_Point_Type (Etype (Right_Opnd (Op_Node)))
then
if Pack /= Standard_Standard then
Error := True;
end if;
else
Opnd_Type := Base_Type (Etype (Right_Opnd (Op_Node)));
if Op_Name = Name_Op_Concat then
Opnd_Type := Base_Type (Typ);
elsif (Scope (Opnd_Type) = Standard_Standard
and then Is_Binary)
or else (Nkind (Right_Opnd (Op_Node)) = N_Attribute_Reference
and then Is_Binary
and then not Comes_From_Source (Opnd_Type))
then
Opnd_Type := Base_Type (Etype (Left_Opnd (Op_Node)));
end if;
if Scope (Opnd_Type) = Standard_Standard then
-- Verify that the scope contains a type that corresponds to
-- the given literal. Optimize the case where Pack is Standard.
if Pack /= Standard_Standard then
if Opnd_Type = Universal_Integer then
Orig_Type := Type_In_P (Is_Integer_Type'Access);
elsif Opnd_Type = Universal_Real then
Orig_Type := Type_In_P (Is_Real_Type'Access);
elsif Opnd_Type = Any_String then
Orig_Type := Type_In_P (Is_String_Type'Access);
elsif Opnd_Type = Any_Access then
Orig_Type := Type_In_P (Is_Definite_Access_Type'Access);
elsif Opnd_Type = Any_Composite then
Orig_Type := Type_In_P (Is_Composite_Type'Access);
if Present (Orig_Type) then
if Has_Private_Component (Orig_Type) then
Orig_Type := Empty;
else
Set_Etype (Act1, Orig_Type);
if Is_Binary then
Set_Etype (Act2, Orig_Type);
end if;
end if;
end if;
else
Orig_Type := Empty;
end if;
Error := No (Orig_Type);
end if;
elsif Ekind (Opnd_Type) = E_Allocator_Type
and then No (Type_In_P (Is_Definite_Access_Type'Access))
then
Error := True;
-- If the type is defined elsewhere, and the operator is not
-- defined in the given scope (by a renaming declaration, e.g.)
-- then this is an error as well. If an extension of System is
-- present, and the type may be defined there, Pack must be
-- System itself.
elsif Scope (Opnd_Type) /= Pack
and then Scope (Op_Id) /= Pack
and then (No (System_Aux_Id)
or else Scope (Opnd_Type) /= System_Aux_Id
or else Pack /= Scope (System_Aux_Id))
then
Error := True;
elsif Pack = Standard_Standard
and then not Operand_Type_In_Scope (Standard_Standard)
then
Error := True;
end if;
end if;
if Error then
Error_Msg_Node_2 := Pack;
Error_Msg_NE
("& not declared in&", N, Selector_Name (Name (N)));
Set_Etype (N, Any_Type);
return;
end if;
end if;
Set_Chars (Op_Node, Op_Name);
Set_Etype (Op_Node, Base_Type (Etype (N)));
Set_Entity (Op_Node, Op_Id);
Generate_Reference (Op_Id, N, ' ');
Rewrite (N, Op_Node);
Resolve (N, Typ);
-- For predefined operators on literals, the operation freezes
-- their type.
if Present (Orig_Type) then
Set_Etype (Act1, Orig_Type);
Freeze_Expression (Act1);
end if;
end Make_Call_Into_Operator;
-------------------
-- Operator_Kind --
-------------------
function Operator_Kind
(Op_Name : Name_Id;
Is_Binary : Boolean)
return Node_Kind
is
Kind : Node_Kind;
begin
if Is_Binary then
if Op_Name = Name_Op_And then Kind := N_Op_And;
elsif Op_Name = Name_Op_Or then Kind := N_Op_Or;
elsif Op_Name = Name_Op_Xor then Kind := N_Op_Xor;
elsif Op_Name = Name_Op_Eq then Kind := N_Op_Eq;
elsif Op_Name = Name_Op_Ne then Kind := N_Op_Ne;
elsif Op_Name = Name_Op_Lt then Kind := N_Op_Lt;
elsif Op_Name = Name_Op_Le then Kind := N_Op_Le;
elsif Op_Name = Name_Op_Gt then Kind := N_Op_Gt;
elsif Op_Name = Name_Op_Ge then Kind := N_Op_Ge;
elsif Op_Name = Name_Op_Add then Kind := N_Op_Add;
elsif Op_Name = Name_Op_Subtract then Kind := N_Op_Subtract;
elsif Op_Name = Name_Op_Concat then Kind := N_Op_Concat;
elsif Op_Name = Name_Op_Multiply then Kind := N_Op_Multiply;
elsif Op_Name = Name_Op_Divide then Kind := N_Op_Divide;
elsif Op_Name = Name_Op_Mod then Kind := N_Op_Mod;
elsif Op_Name = Name_Op_Rem then Kind := N_Op_Rem;
elsif Op_Name = Name_Op_Expon then Kind := N_Op_Expon;
else
raise Program_Error;
end if;
-- Unary operators
else
if Op_Name = Name_Op_Add then Kind := N_Op_Plus;
elsif Op_Name = Name_Op_Subtract then Kind := N_Op_Minus;
elsif Op_Name = Name_Op_Abs then Kind := N_Op_Abs;
elsif Op_Name = Name_Op_Not then Kind := N_Op_Not;
else
raise Program_Error;
end if;
end if;
return Kind;
end Operator_Kind;
-----------------------------
-- Pre_Analyze_And_Resolve --
-----------------------------
procedure Pre_Analyze_And_Resolve (N : Node_Id; T : Entity_Id) is
Save_Full_Analysis : constant Boolean := Full_Analysis;
begin
Full_Analysis := False;
Expander_Mode_Save_And_Set (False);
-- We suppress all checks for this analysis, since the checks will
-- be applied properly, and in the right location, when the default
-- expression is reanalyzed and reexpanded later on.
Analyze_And_Resolve (N, T, Suppress => All_Checks);
Expander_Mode_Restore;
Full_Analysis := Save_Full_Analysis;
end Pre_Analyze_And_Resolve;
-- Version without context type.
procedure Pre_Analyze_And_Resolve (N : Node_Id) is
Save_Full_Analysis : constant Boolean := Full_Analysis;
begin
Full_Analysis := False;
Expander_Mode_Save_And_Set (False);
Analyze (N);
Resolve (N, Etype (N), Suppress => All_Checks);
Expander_Mode_Restore;
Full_Analysis := Save_Full_Analysis;
end Pre_Analyze_And_Resolve;
----------------------------------
-- Replace_Actual_Discriminants --
----------------------------------
procedure Replace_Actual_Discriminants (N : Node_Id; Default : Node_Id) is
Loc : constant Source_Ptr := Sloc (N);
Tsk : Node_Id := Empty;
function Process_Discr (Nod : Node_Id) return Traverse_Result;
-------------------
-- Process_Discr --
-------------------
function Process_Discr (Nod : Node_Id) return Traverse_Result is
Ent : Entity_Id;
begin
if Nkind (Nod) = N_Identifier then
Ent := Entity (Nod);
if Present (Ent)
and then Ekind (Ent) = E_Discriminant
then
Rewrite (Nod,
Make_Selected_Component (Loc,
Prefix => New_Copy_Tree (Tsk, New_Sloc => Loc),
Selector_Name => Make_Identifier (Loc, Chars (Ent))));
Set_Etype (Nod, Etype (Ent));
end if;
end if;
return OK;
end Process_Discr;
procedure Replace_Discrs is new Traverse_Proc (Process_Discr);
-- Start of processing for Replace_Actual_Discriminants
begin
if not Expander_Active then
return;
end if;
if Nkind (Name (N)) = N_Selected_Component then
Tsk := Prefix (Name (N));
elsif Nkind (Name (N)) = N_Indexed_Component then
Tsk := Prefix (Prefix (Name (N)));
end if;
if No (Tsk) then
return;
else
Replace_Discrs (Default);
end if;
end Replace_Actual_Discriminants;
-------------
-- Resolve --
-------------
procedure Resolve (N : Node_Id; Typ : Entity_Id) is
I : Interp_Index;
I1 : Interp_Index := 0; -- prevent junk warning
It : Interp;
It1 : Interp;
Found : Boolean := False;
Seen : Entity_Id := Empty; -- prevent junk warning
Ctx_Type : Entity_Id := Typ;
Expr_Type : Entity_Id := Empty; -- prevent junk warning
Ambiguous : Boolean := False;
procedure Patch_Up_Value (N : Node_Id; Typ : Entity_Id);
-- Try and fix up a literal so that it matches its expected type. New
-- literals are manufactured if necessary to avoid cascaded errors.
procedure Resolution_Failed;
-- Called when attempt at resolving current expression fails
--------------------
-- Patch_Up_Value --
--------------------
procedure Patch_Up_Value (N : Node_Id; Typ : Entity_Id) is
begin
if Nkind (N) = N_Integer_Literal
and then Is_Real_Type (Typ)
then
Rewrite (N,
Make_Real_Literal (Sloc (N),
Realval => UR_From_Uint (Intval (N))));
Set_Etype (N, Universal_Real);
Set_Is_Static_Expression (N);
elsif Nkind (N) = N_Real_Literal
and then Is_Integer_Type (Typ)
then
Rewrite (N,
Make_Integer_Literal (Sloc (N),
Intval => UR_To_Uint (Realval (N))));
Set_Etype (N, Universal_Integer);
Set_Is_Static_Expression (N);
elsif Nkind (N) = N_String_Literal
and then Is_Character_Type (Typ)
then
Set_Character_Literal_Name (Char_Code (Character'Pos ('A')));
Rewrite (N,
Make_Character_Literal (Sloc (N),
Chars => Name_Find,
Char_Literal_Value => Char_Code (Character'Pos ('A'))));
Set_Etype (N, Any_Character);
Set_Is_Static_Expression (N);
elsif Nkind (N) /= N_String_Literal
and then Is_String_Type (Typ)
then
Rewrite (N,
Make_String_Literal (Sloc (N),
Strval => End_String));
elsif Nkind (N) = N_Range then
Patch_Up_Value (Low_Bound (N), Typ);
Patch_Up_Value (High_Bound (N), Typ);
end if;
end Patch_Up_Value;
-----------------------
-- Resolution_Failed --
-----------------------
procedure Resolution_Failed is
begin
Patch_Up_Value (N, Typ);
Set_Etype (N, Typ);
Debug_A_Exit ("resolving ", N, " (done, resolution failed)");
Set_Is_Overloaded (N, False);
-- The caller will return without calling the expander, so we need
-- to set the analyzed flag. Note that it is fine to set Analyzed
-- to True even if we are in the middle of a shallow analysis,
-- (see the spec of sem for more details) since this is an error
-- situation anyway, and there is no point in repeating the
-- analysis later (indeed it won't work to repeat it later, since
-- we haven't got a clear resolution of which entity is being
-- referenced.)
Set_Analyzed (N, True);
return;
end Resolution_Failed;
-- Start of processing for Resolve
begin
if N = Error then
return;
end if;
-- Access attribute on remote subprogram cannot be used for
-- a non-remote access-to-subprogram type.
if Nkind (N) = N_Attribute_Reference
and then (Attribute_Name (N) = Name_Access
or else Attribute_Name (N) = Name_Unrestricted_Access
or else Attribute_Name (N) = Name_Unchecked_Access)
and then Comes_From_Source (N)
and then Is_Entity_Name (Prefix (N))
and then Is_Subprogram (Entity (Prefix (N)))
and then Is_Remote_Call_Interface (Entity (Prefix (N)))
and then not Is_Remote_Access_To_Subprogram_Type (Typ)
then
Error_Msg_N
("prefix must statically denote a non-remote subprogram", N);
end if;
-- If the context is a Remote_Access_To_Subprogram, access attributes
-- must be resolved with the corresponding fat pointer. There is no need
-- to check for the attribute name since the return type of an
-- attribute is never a remote type.
if Nkind (N) = N_Attribute_Reference
and then Comes_From_Source (N)
and then (Is_Remote_Call_Interface (Typ)
or else Is_Remote_Types (Typ))
then
declare
Attr : constant Attribute_Id :=
Get_Attribute_Id (Attribute_Name (N));
Pref : constant Node_Id := Prefix (N);
Decl : Node_Id;
Spec : Node_Id;
Is_Remote : Boolean := True;
begin
-- Check that Typ is a fat pointer with a reference to a RAS as
-- original access type.
if
(Ekind (Typ) = E_Access_Subprogram_Type
and then Present (Equivalent_Type (Typ)))
or else
(Ekind (Typ) = E_Record_Type
and then Present (Corresponding_Remote_Type (Typ)))
then
-- Prefix (N) must statically denote a remote subprogram
-- declared in a package specification.
if Attr = Attribute_Access then
Decl := Unit_Declaration_Node (Entity (Pref));
if Nkind (Decl) = N_Subprogram_Body then
Spec := Corresponding_Spec (Decl);
if not No (Spec) then
Decl := Unit_Declaration_Node (Spec);
end if;
end if;
Spec := Parent (Decl);
if not Is_Entity_Name (Prefix (N))
or else Nkind (Spec) /= N_Package_Specification
or else
not Is_Remote_Call_Interface (Defining_Entity (Spec))
then
Is_Remote := False;
Error_Msg_N
("prefix must statically denote a remote subprogram ",
N);
end if;
end if;
if Attr = Attribute_Access
or else Attr = Attribute_Unchecked_Access
or else Attr = Attribute_Unrestricted_Access
then
Check_Subtype_Conformant
(New_Id => Entity (Prefix (N)),
Old_Id => Designated_Type
(Corresponding_Remote_Type (Typ)),
Err_Loc => N);
if Is_Remote then
Process_Remote_AST_Attribute (N, Typ);
end if;
end if;
end if;
end;
end if;
Debug_A_Entry ("resolving ", N);
if Is_Fixed_Point_Type (Typ) then
Check_Restriction (No_Fixed_Point, N);
elsif Is_Floating_Point_Type (Typ)
and then Typ /= Universal_Real
and then Typ /= Any_Real
then
Check_Restriction (No_Floating_Point, N);
end if;
-- Return if already analyzed
if Analyzed (N) then
Debug_A_Exit ("resolving ", N, " (done, already analyzed)");
return;
-- Return if type = Any_Type (previous error encountered)
elsif Etype (N) = Any_Type then
Debug_A_Exit ("resolving ", N, " (done, Etype = Any_Type)");
return;
end if;
Check_Parameterless_Call (N);
-- If not overloaded, then we know the type, and all that needs doing
-- is to check that this type is compatible with the context.
if not Is_Overloaded (N) then
Found := Covers (Typ, Etype (N));
Expr_Type := Etype (N);
-- In the overloaded case, we must select the interpretation that
-- is compatible with the context (i.e. the type passed to Resolve)
else
Get_First_Interp (N, I, It);
-- Loop through possible interpretations
Interp_Loop : while Present (It.Typ) loop
-- We are only interested in interpretations that are compatible
-- with the expected type, any other interpretations are ignored
if Covers (Typ, It.Typ) then
-- First matching interpretation
if not Found then
Found := True;
I1 := I;
Seen := It.Nam;
Expr_Type := It.Typ;
-- Matching intepretation that is not the first, maybe an
-- error, but there are some cases where preference rules are
-- used to choose between the two possibilities. These and
-- some more obscure cases are handled in Disambiguate.
else
Error_Msg_Sloc := Sloc (Seen);
It1 := Disambiguate (N, I1, I, Typ);
if It1 = No_Interp then
-- Before we issue an ambiguity complaint, check for
-- the case of a subprogram call where at least one
-- of the arguments is Any_Type, and if so, suppress
-- the message, since it is a cascaded error.
if Nkind (N) = N_Function_Call
or else Nkind (N) = N_Procedure_Call_Statement
then
declare
A : Node_Id := First_Actual (N);
E : Node_Id;
begin
while Present (A) loop
E := A;
if Nkind (E) = N_Parameter_Association then
E := Explicit_Actual_Parameter (E);
end if;
if Etype (E) = Any_Type then
if Debug_Flag_V then
Write_Str ("Any_Type in call");
Write_Eol;
end if;
exit Interp_Loop;
end if;
Next_Actual (A);
end loop;
end;
elsif Nkind (N) in N_Binary_Op
and then (Etype (Left_Opnd (N)) = Any_Type
or else Etype (Right_Opnd (N)) = Any_Type)
then
exit Interp_Loop;
elsif Nkind (N) in N_Unary_Op
and then Etype (Right_Opnd (N)) = Any_Type
then
exit Interp_Loop;
end if;
-- Not that special case, so issue message using the
-- flag Ambiguous to control printing of the header
-- message only at the start of an ambiguous set.
if not Ambiguous then
Error_Msg_NE
("ambiguous expression (cannot resolve&)!",
N, It.Nam);
Error_Msg_N
("possible interpretation#!", N);
Ambiguous := True;
end if;
Error_Msg_Sloc := Sloc (It.Nam);
Error_Msg_N ("possible interpretation#!", N);
-- Disambiguation has succeeded. Skip the remaining
-- interpretations.
else
Seen := It1.Nam;
Expr_Type := It1.Typ;
while Present (It.Typ) loop
Get_Next_Interp (I, It);
end loop;
end if;
end if;
-- We have a matching interpretation, Expr_Type is the
-- type from this interpretation, and Seen is the entity.
-- For an operator, just set the entity name. The type will
-- be set by the specific operator resolution routine.
if Nkind (N) in N_Op then
Set_Entity (N, Seen);
Generate_Reference (Seen, N);
elsif Nkind (N) = N_Character_Literal then
Set_Etype (N, Expr_Type);
-- For an explicit dereference, attribute reference, range,
-- short-circuit form (which is not an operator node),
-- or a call with a name that is an explicit dereference,
-- there is nothing to be done at this point.
elsif Nkind (N) = N_Explicit_Dereference
or else Nkind (N) = N_Attribute_Reference
or else Nkind (N) = N_And_Then
or else Nkind (N) = N_Indexed_Component
or else Nkind (N) = N_Or_Else
or else Nkind (N) = N_Range
or else Nkind (N) = N_Selected_Component
or else Nkind (N) = N_Slice
or else Nkind (Name (N)) = N_Explicit_Dereference
then
null;
-- For procedure or function calls, set the type of the
-- name, and also the entity pointer for the prefix
elsif (Nkind (N) = N_Procedure_Call_Statement
or else Nkind (N) = N_Function_Call)
and then (Is_Entity_Name (Name (N))
or else Nkind (Name (N)) = N_Operator_Symbol)
then
Set_Etype (Name (N), Expr_Type);
Set_Entity (Name (N), Seen);
Generate_Reference (Seen, Name (N));
elsif Nkind (N) = N_Function_Call
and then Nkind (Name (N)) = N_Selected_Component
then
Set_Etype (Name (N), Expr_Type);
Set_Entity (Selector_Name (Name (N)), Seen);
Generate_Reference (Seen, Selector_Name (Name (N)));
-- For all other cases, just set the type of the Name
else
Set_Etype (Name (N), Expr_Type);
end if;
-- Here if interpetation is incompatible with context type
else
if Debug_Flag_V then
Write_Str (" intepretation incompatible with context");
Write_Eol;
end if;
end if;
-- Move to next interpretation
exit Interp_Loop when not Present (It.Typ);
Get_Next_Interp (I, It);
end loop Interp_Loop;
end if;
-- At this stage Found indicates whether or not an acceptable
-- interpretation exists. If not, then we have an error, except
-- that if the context is Any_Type as a result of some other error,
-- then we suppress the error report.
if not Found then
if Typ /= Any_Type then
-- If type we are looking for is Void, then this is the
-- procedure call case, and the error is simply that what
-- we gave is not a procedure name (we think of procedure
-- calls as expressions with types internally, but the user
-- doesn't think of them this way!)
if Typ = Standard_Void_Type then
Error_Msg_N ("expect procedure name in procedure call", N);
Found := True;
-- Otherwise we do have a subexpression with the wrong type
-- Check for the case of an allocator which uses an access
-- type instead of the designated type. This is a common
-- error and we specialize the message, posting an error
-- on the operand of the allocator, complaining that we
-- expected the designated type of the allocator.
elsif Nkind (N) = N_Allocator
and then Ekind (Typ) in Access_Kind
and then Ekind (Etype (N)) in Access_Kind
and then Designated_Type (Etype (N)) = Typ
then
Wrong_Type (Expression (N), Designated_Type (Typ));
Found := True;
-- Check for view mismatch on Null in instances, for
-- which the view-swapping mechanism has no identifier.
elsif (In_Instance or else In_Inlined_Body)
and then (Nkind (N) = N_Null)
and then Is_Private_Type (Typ)
and then Is_Access_Type (Full_View (Typ))
then
Resolve (N, Full_View (Typ));
Set_Etype (N, Typ);
return;
-- Check for an aggregate. Sometimes we can get bogus
-- aggregates from misuse of parentheses, and we are
-- about to complain about the aggregate without even
-- looking inside it.
-- Instead, if we have an aggregate of type Any_Composite,
-- then analyze and resolve the component fields, and then
-- only issue another message if we get no errors doing
-- this (otherwise assume that the errors in the aggregate
-- caused the problem).
elsif Nkind (N) = N_Aggregate
and then Etype (N) = Any_Composite
then
-- Disable expansion in any case. If there is a type mismatch
-- it may be fatal to try to expand the aggregate. The flag
-- would otherwise be set to false when the error is posted.
Expander_Active := False;
declare
procedure Check_Aggr (Aggr : Node_Id);
-- Check one aggregate, and set Found to True if we
-- have a definite error in any of its elements
procedure Check_Elmt (Aelmt : Node_Id);
-- Check one element of aggregate and set Found to
-- True if we definitely have an error in the element.
procedure Check_Aggr (Aggr : Node_Id) is
Elmt : Node_Id;
begin
if Present (Expressions (Aggr)) then
Elmt := First (Expressions (Aggr));
while Present (Elmt) loop
Check_Elmt (Elmt);
Next (Elmt);
end loop;
end if;
if Present (Component_Associations (Aggr)) then
Elmt := First (Component_Associations (Aggr));
while Present (Elmt) loop
Check_Elmt (Expression (Elmt));
Next (Elmt);
end loop;
end if;
end Check_Aggr;
procedure Check_Elmt (Aelmt : Node_Id) is
begin
-- If we have a nested aggregate, go inside it (to
-- attempt a naked analyze-resolve of the aggregate
-- can cause undesirable cascaded errors). Do not
-- resolve expression if it needs a type from context,
-- as for integer * fixed expression.
if Nkind (Aelmt) = N_Aggregate then
Check_Aggr (Aelmt);
else
Analyze (Aelmt);
if not Is_Overloaded (Aelmt)
and then Etype (Aelmt) /= Any_Fixed
then
Resolve (Aelmt, Etype (Aelmt));
end if;
if Etype (Aelmt) = Any_Type then
Found := True;
end if;
end if;
end Check_Elmt;
begin
Check_Aggr (N);
end;
end if;
-- If an error message was issued already, Found got reset
-- to True, so if it is still False, issue the standard
-- Wrong_Type message.
if not Found then
if Is_Overloaded (N)
and then Nkind (N) = N_Function_Call
then
Error_Msg_Node_2 := Typ;
Error_Msg_NE ("no visible interpretation of&" &
" matches expected type&", N, Name (N));
if All_Errors_Mode then
declare
Index : Interp_Index;
It : Interp;
begin
Error_Msg_N ("\possible interpretations:", N);
Get_First_Interp (Name (N), Index, It);
while Present (It.Nam) loop
Error_Msg_Sloc := Sloc (It.Nam);
Error_Msg_Node_2 := It.Typ;
Error_Msg_NE ("\& declared#, type&",
N, It.Nam);
Get_Next_Interp (Index, It);
end loop;
end;
else
Error_Msg_N ("\use -gnatf for details", N);
end if;
else
Wrong_Type (N, Typ);
end if;
end if;
end if;
Resolution_Failed;
return;
-- Test if we have more than one interpretation for the context
elsif Ambiguous then
Resolution_Failed;
return;
-- Here we have an acceptable interpretation for the context
else
-- A user-defined operator is tranformed into a function call at
-- this point, so that further processing knows that operators are
-- really operators (i.e. are predefined operators). User-defined
-- operators that are intrinsic are just renamings of the predefined
-- ones, and need not be turned into calls either, but if they rename
-- a different operator, we must transform the node accordingly.
-- Instantiations of Unchecked_Conversion are intrinsic but are
-- treated as functions, even if given an operator designator.
if Nkind (N) in N_Op
and then Present (Entity (N))
and then Ekind (Entity (N)) /= E_Operator
then
if not Is_Predefined_Op (Entity (N)) then
Rewrite_Operator_As_Call (N, Entity (N));
elsif Present (Alias (Entity (N))) then
Rewrite_Renamed_Operator (N, Alias (Entity (N)));
end if;
end if;
-- Propagate type information and normalize tree for various
-- predefined operations. If the context only imposes a class of
-- types, rather than a specific type, propagate the actual type
-- downward.
if Typ = Any_Integer
or else Typ = Any_Boolean
or else Typ = Any_Modular
or else Typ = Any_Real
or else Typ = Any_Discrete
then
Ctx_Type := Expr_Type;
-- Any_Fixed is legal in a real context only if a specific
-- fixed point type is imposed. If Norman Cohen can be
-- confused by this, it deserves a separate message.
if Typ = Any_Real
and then Expr_Type = Any_Fixed
then
Error_Msg_N ("Illegal context for mixed mode operation", N);
Set_Etype (N, Universal_Real);
Ctx_Type := Universal_Real;
end if;
end if;
case N_Subexpr'(Nkind (N)) is
when N_Aggregate => Resolve_Aggregate (N, Ctx_Type);
when N_Allocator => Resolve_Allocator (N, Ctx_Type);
when N_And_Then | N_Or_Else
=> Resolve_Short_Circuit (N, Ctx_Type);
when N_Attribute_Reference
=> Resolve_Attribute (N, Ctx_Type);
when N_Character_Literal
=> Resolve_Character_Literal (N, Ctx_Type);
when N_Conditional_Expression
=> Resolve_Conditional_Expression (N, Ctx_Type);
when N_Expanded_Name
=> Resolve_Entity_Name (N, Ctx_Type);
when N_Extension_Aggregate
=> Resolve_Extension_Aggregate (N, Ctx_Type);
when N_Explicit_Dereference
=> Resolve_Explicit_Dereference (N, Ctx_Type);
when N_Function_Call
=> Resolve_Call (N, Ctx_Type);
when N_Identifier
=> Resolve_Entity_Name (N, Ctx_Type);
when N_In | N_Not_In
=> Resolve_Membership_Op (N, Ctx_Type);
when N_Indexed_Component
=> Resolve_Indexed_Component (N, Ctx_Type);
when N_Integer_Literal
=> Resolve_Integer_Literal (N, Ctx_Type);
when N_Null => Resolve_Null (N, Ctx_Type);
when N_Op_And | N_Op_Or | N_Op_Xor
=> Resolve_Logical_Op (N, Ctx_Type);
when N_Op_Eq | N_Op_Ne
=> Resolve_Equality_Op (N, Ctx_Type);
when N_Op_Lt | N_Op_Le | N_Op_Gt | N_Op_Ge
=> Resolve_Comparison_Op (N, Ctx_Type);
when N_Op_Not => Resolve_Op_Not (N, Ctx_Type);
when N_Op_Add | N_Op_Subtract | N_Op_Multiply |
N_Op_Divide | N_Op_Mod | N_Op_Rem
=> Resolve_Arithmetic_Op (N, Ctx_Type);
when N_Op_Concat => Resolve_Op_Concat (N, Ctx_Type);
when N_Op_Expon => Resolve_Op_Expon (N, Ctx_Type);
when N_Op_Plus | N_Op_Minus | N_Op_Abs
=> Resolve_Unary_Op (N, Ctx_Type);
when N_Op_Shift => Resolve_Shift (N, Ctx_Type);
when N_Procedure_Call_Statement
=> Resolve_Call (N, Ctx_Type);
when N_Operator_Symbol
=> Resolve_Operator_Symbol (N, Ctx_Type);
when N_Qualified_Expression
=> Resolve_Qualified_Expression (N, Ctx_Type);
when N_Raise_xxx_Error
=> Set_Etype (N, Ctx_Type);
when N_Range => Resolve_Range (N, Ctx_Type);
when N_Real_Literal
=> Resolve_Real_Literal (N, Ctx_Type);
when N_Reference => Resolve_Reference (N, Ctx_Type);
when N_Selected_Component
=> Resolve_Selected_Component (N, Ctx_Type);
when N_Slice => Resolve_Slice (N, Ctx_Type);
when N_String_Literal
=> Resolve_String_Literal (N, Ctx_Type);
when N_Subprogram_Info
=> Resolve_Subprogram_Info (N, Ctx_Type);
when N_Type_Conversion
=> Resolve_Type_Conversion (N, Ctx_Type);
when N_Unchecked_Expression =>
Resolve_Unchecked_Expression (N, Ctx_Type);
when N_Unchecked_Type_Conversion =>
Resolve_Unchecked_Type_Conversion (N, Ctx_Type);
end case;
-- If the subexpression was replaced by a non-subexpression, then
-- all we do is to expand it. The only legitimate case we know of
-- is converting procedure call statement to entry call statements,
-- but there may be others, so we are making this test general.
if Nkind (N) not in N_Subexpr then
Debug_A_Exit ("resolving ", N, " (done)");
Expand (N);
return;
end if;
-- The expression is definitely NOT overloaded at this point, so
-- we reset the Is_Overloaded flag to avoid any confusion when
-- reanalyzing the node.
Set_Is_Overloaded (N, False);
-- Freeze expression type, entity if it is a name, and designated
-- type if it is an allocator (RM 13.14(9,10)).
-- Now that the resolution of the type of the node is complete,
-- and we did not detect an error, we can expand this node. We
-- skip the expand call if we are in a default expression, see
-- section "Handling of Default Expressions" in Sem spec.
Debug_A_Exit ("resolving ", N, " (done)");
-- We unconditionally freeze the expression, even if we are in
-- default expression mode (the Freeze_Expression routine tests
-- this flag and only freezes static types if it is set).
Freeze_Expression (N);
-- Now we can do the expansion
Expand (N);
end if;
end Resolve;
-- Version with check(s) suppressed
procedure Resolve (N : Node_Id; Typ : Entity_Id; Suppress : Check_Id) is
begin
if Suppress = All_Checks then
declare
Svg : constant Suppress_Record := Scope_Suppress;
begin
Scope_Suppress := (others => True);
Resolve (N, Typ);
Scope_Suppress := Svg;
end;
else
declare
Svg : constant Boolean := Get_Scope_Suppress (Suppress);
begin
Set_Scope_Suppress (Suppress, True);
Resolve (N, Typ);
Set_Scope_Suppress (Suppress, Svg);
end;
end if;
end Resolve;
---------------------
-- Resolve_Actuals --
---------------------
procedure Resolve_Actuals (N : Node_Id; Nam : Entity_Id) is
Loc : constant Source_Ptr := Sloc (N);
A : Node_Id;
F : Entity_Id;
A_Typ : Entity_Id;
F_Typ : Entity_Id;
Prev : Node_Id := Empty;
procedure Insert_Default;
-- If the actual is missing in a call, insert in the actuals list
-- an instance of the default expression. The insertion is always
-- a named association.
--------------------
-- Insert_Default --
--------------------
procedure Insert_Default is
Actval : Node_Id;
Assoc : Node_Id;
begin
-- Note that we do a full New_Copy_Tree, so that any associated
-- Itypes are properly copied. This may not be needed any more,
-- but it does no harm as a safety measure! Defaults of a generic
-- formal may be out of bounds of the corresponding actual (see
-- cc1311b) and an additional check may be required.
if Present (Default_Value (F)) then
Actval := New_Copy_Tree (Default_Value (F),
New_Scope => Current_Scope, New_Sloc => Loc);
if Is_Concurrent_Type (Scope (Nam))
and then Has_Discriminants (Scope (Nam))
then
Replace_Actual_Discriminants (N, Actval);
end if;
if Is_Overloadable (Nam)
and then Present (Alias (Nam))
then
if Base_Type (Etype (F)) /= Base_Type (Etype (Actval))
and then not Is_Tagged_Type (Etype (F))
then
-- If default is a real literal, do not introduce a
-- conversion whose effect may depend on the run-time
-- size of universal real.
if Nkind (Actval) = N_Real_Literal then
Set_Etype (Actval, Base_Type (Etype (F)));
else
Actval := Unchecked_Convert_To (Etype (F), Actval);
end if;
end if;
if Is_Scalar_Type (Etype (F)) then
Enable_Range_Check (Actval);
end if;
Set_Parent (Actval, N);
Analyze_And_Resolve (Actval, Etype (Actval));
else
Set_Parent (Actval, N);
-- Resolve aggregates with their base type, to avoid scope
-- anomalies: the subtype was first built in the suprogram
-- declaration, and the current call may be nested.
if Nkind (Actval) = N_Aggregate
and then Has_Discriminants (Etype (Actval))
then
Analyze_And_Resolve (Actval, Base_Type (Etype (Actval)));
else
Analyze_And_Resolve (Actval, Etype (Actval));
end if;
end if;
-- If default is a tag indeterminate function call, propagate
-- tag to obtain proper dispatching.
if Is_Controlling_Formal (F)
and then Nkind (Default_Value (F)) = N_Function_Call
then
Set_Is_Controlling_Actual (Actval);
end if;
else
-- Missing argument in call, nothing to insert.
return;
end if;
-- If the default expression raises constraint error, then just
-- silently replace it with an N_Raise_Constraint_Error node,
-- since we already gave the warning on the subprogram spec.
if Raises_Constraint_Error (Actval) then
Rewrite (Actval,
Make_Raise_Constraint_Error (Loc));
Set_Raises_Constraint_Error (Actval);
Set_Etype (Actval, Etype (F));
end if;
Assoc :=
Make_Parameter_Association (Loc,
Explicit_Actual_Parameter => Actval,
Selector_Name => Make_Identifier (Loc, Chars (F)));
-- Case of insertion is first named actual
if No (Prev) or else
Nkind (Parent (Prev)) /= N_Parameter_Association
then
Set_Next_Named_Actual (Assoc, First_Named_Actual (N));
Set_First_Named_Actual (N, Actval);
if No (Prev) then
if not Present (Parameter_Associations (N)) then
Set_Parameter_Associations (N, New_List (Assoc));
else
Append (Assoc, Parameter_Associations (N));
end if;
else
Insert_After (Prev, Assoc);
end if;
-- Case of insertion is not first named actual
else
Set_Next_Named_Actual
(Assoc, Next_Named_Actual (Parent (Prev)));
Set_Next_Named_Actual (Parent (Prev), Actval);
Append (Assoc, Parameter_Associations (N));
end if;
Mark_Rewrite_Insertion (Assoc);
Mark_Rewrite_Insertion (Actval);
Prev := Actval;
end Insert_Default;
-- Start of processing for Resolve_Actuals
begin
A := First_Actual (N);
F := First_Formal (Nam);
while Present (F) loop
if Present (A)
and then (Nkind (Parent (A)) /= N_Parameter_Association
or else
Chars (Selector_Name (Parent (A))) = Chars (F))
then
-- If the formal is Out or In_Out, do not resolve and expand the
-- conversion, because it is subsequently expanded into explicit
-- temporaries and assignments. However, the object of the
-- conversion can be resolved. An exception is the case of
-- a tagged type conversion with a class-wide actual. In that
-- case we want the tag check to occur and no temporary will
-- will be needed (no representation change can occur) and
-- the parameter is passed by reference, so we go ahead and
-- resolve the type conversion.
if Ekind (F) /= E_In_Parameter
and then Nkind (A) = N_Type_Conversion
and then not Is_Class_Wide_Type (Etype (Expression (A)))
then
if Conversion_OK (A)
or else Valid_Conversion (A, Etype (A), Expression (A))
then
Resolve (Expression (A), Etype (Expression (A)));
end if;
else
Resolve (A, Etype (F));
end if;
A_Typ := Etype (A);
F_Typ := Etype (F);
if Ekind (F) /= E_In_Parameter
and then not Is_OK_Variable_For_Out_Formal (A)
then
-- Specialize error message for protected procedure call
-- within function call of the same protected object.
if Is_Entity_Name (A)
and then Chars (Entity (A)) = Name_uObject
and then Ekind (Current_Scope) = E_Function
and then Convention (Current_Scope) = Convention_Protected
and then Ekind (Nam) /= E_Function
then
Error_Msg_N ("within protected function, protected " &
"object is constant", A);
Error_Msg_N ("\cannot call operation that may modify it", A);
else
Error_Msg_NE ("actual for& must be a variable", A, F);
end if;
end if;
if Ekind (F) /= E_Out_Parameter then
Check_Unset_Reference (A);
if Ada_83
and then Is_Entity_Name (A)
and then Ekind (Entity (A)) = E_Out_Parameter
then
Error_Msg_N ("(Ada 83) illegal reading of out parameter", A);
end if;
end if;
-- Apply appropriate range checks for in, out, and in-out
-- parameters. Out and in-out parameters also need a separate
-- check, if there is a type conversion, to make sure the return
-- value meets the constraints of the variable before the
-- conversion.
-- Gigi looks at the check flag and uses the appropriate types.
-- For now since one flag is used there is an optimization which
-- might not be done in the In Out case since Gigi does not do
-- any analysis. More thought required about this ???
if Ekind (F) = E_In_Parameter
or else Ekind (F) = E_In_Out_Parameter
then
if Is_Scalar_Type (Etype (A)) then
Apply_Scalar_Range_Check (A, F_Typ);
elsif Is_Array_Type (Etype (A)) then
Apply_Length_Check (A, F_Typ);
elsif Is_Record_Type (F_Typ)
and then Has_Discriminants (F_Typ)
and then Is_Constrained (F_Typ)
and then (not Is_Derived_Type (F_Typ)
or else Comes_From_Source (Nam))
then
Apply_Discriminant_Check (A, F_Typ);
elsif Is_Access_Type (F_Typ)
and then Is_Array_Type (Designated_Type (F_Typ))
and then Is_Constrained (Designated_Type (F_Typ))
then
Apply_Length_Check (A, F_Typ);
elsif Is_Access_Type (F_Typ)
and then Has_Discriminants (Designated_Type (F_Typ))
and then Is_Constrained (Designated_Type (F_Typ))
then
Apply_Discriminant_Check (A, F_Typ);
else
Apply_Range_Check (A, F_Typ);
end if;
end if;
if Ekind (F) = E_Out_Parameter
or else Ekind (F) = E_In_Out_Parameter
then
if Nkind (A) = N_Type_Conversion then
if Is_Scalar_Type (A_Typ) then
Apply_Scalar_Range_Check
(Expression (A), Etype (Expression (A)), A_Typ);
else
Apply_Range_Check
(Expression (A), Etype (Expression (A)), A_Typ);
end if;
else
if Is_Scalar_Type (F_Typ) then
Apply_Scalar_Range_Check (A, A_Typ, F_Typ);
elsif Is_Array_Type (F_Typ)
and then Ekind (F) = E_Out_Parameter
then
Apply_Length_Check (A, F_Typ);
else
Apply_Range_Check (A, A_Typ, F_Typ);
end if;
end if;
end if;
-- An actual associated with an access parameter is implicitly
-- converted to the anonymous access type of the formal and
-- must satisfy the legality checks for access conversions.
if Ekind (F_Typ) = E_Anonymous_Access_Type then
if not Valid_Conversion (A, F_Typ, A) then
Error_Msg_N
("invalid implicit conversion for access parameter", A);
end if;
end if;
-- Check bad case of atomic/volatile argument (RM C.6(12))
if Is_By_Reference_Type (Etype (F))
and then Comes_From_Source (N)
then
if Is_Atomic_Object (A)
and then not Is_Atomic (Etype (F))
then
Error_Msg_N
("cannot pass atomic argument to non-atomic formal",
N);
elsif Is_Volatile_Object (A)
and then not Is_Volatile (Etype (F))
then
Error_Msg_N
("cannot pass volatile argument to non-volatile formal",
N);
end if;
end if;
-- Check that subprograms don't have improper controlling
-- arguments (RM 3.9.2 (9))
if Is_Controlling_Formal (F) then
Set_Is_Controlling_Actual (A);
elsif Nkind (A) = N_Explicit_Dereference then
Validate_Remote_Access_To_Class_Wide_Type (A);
end if;
if (Is_Class_Wide_Type (A_Typ) or else Is_Dynamically_Tagged (A))
and then not Is_Class_Wide_Type (F_Typ)
and then not Is_Controlling_Formal (F)
then
Error_Msg_N ("class-wide argument not allowed here!", A);
if Is_Subprogram (Nam) then
Error_Msg_Node_2 := F_Typ;
Error_Msg_NE
("& is not a primitive operation of &!", A, Nam);
end if;
elsif Is_Access_Type (A_Typ)
and then Is_Access_Type (F_Typ)
and then Ekind (F_Typ) /= E_Access_Subprogram_Type
and then (Is_Class_Wide_Type (Designated_Type (A_Typ))
or else (Nkind (A) = N_Attribute_Reference
and then Is_Class_Wide_Type (Etype (Prefix (A)))))
and then not Is_Class_Wide_Type (Designated_Type (F_Typ))
and then not Is_Controlling_Formal (F)
then
Error_Msg_N
("access to class-wide argument not allowed here!", A);
if Is_Subprogram (Nam) then
Error_Msg_Node_2 := Designated_Type (F_Typ);
Error_Msg_NE
("& is not a primitive operation of &!", A, Nam);
end if;
end if;
Eval_Actual (A);
-- If it is a named association, treat the selector_name as
-- a proper identifier, and mark the corresponding entity.
if Nkind (Parent (A)) = N_Parameter_Association then
Set_Entity (Selector_Name (Parent (A)), F);
Generate_Reference (F, Selector_Name (Parent (A)));
Set_Etype (Selector_Name (Parent (A)), F_Typ);
Generate_Reference (F_Typ, N, ' ');
end if;
Prev := A;
Next_Actual (A);
else
Insert_Default;
end if;
Next_Formal (F);
end loop;
end Resolve_Actuals;
-----------------------
-- Resolve_Allocator --
-----------------------
procedure Resolve_Allocator (N : Node_Id; Typ : Entity_Id) is
E : constant Node_Id := Expression (N);
Subtyp : Entity_Id;
Discrim : Entity_Id;
Constr : Node_Id;
Disc_Exp : Node_Id;
begin
-- Replace general access with specific type
if Ekind (Etype (N)) = E_Allocator_Type then
Set_Etype (N, Base_Type (Typ));
end if;
if Is_Abstract (Typ) then
Error_Msg_N ("type of allocator cannot be abstract", N);
end if;
-- For qualified expression, resolve the expression using the
-- given subtype (nothing to do for type mark, subtype indication)
if Nkind (E) = N_Qualified_Expression then
if Is_Class_Wide_Type (Etype (E))
and then not Is_Class_Wide_Type (Designated_Type (Typ))
then
Error_Msg_N
("class-wide allocator not allowed for this access type", N);
end if;
Resolve (Expression (E), Etype (E));
Check_Unset_Reference (Expression (E));
-- For a subtype mark or subtype indication, freeze the subtype
else
Freeze_Expression (E);
if Is_Access_Constant (Typ) and then not No_Initialization (N) then
Error_Msg_N
("initialization required for access-to-constant allocator", N);
end if;
-- A special accessibility check is needed for allocators that
-- constrain access discriminants. The level of the type of the
-- expression used to contrain an access discriminant cannot be
-- deeper than the type of the allocator (in constrast to access
-- parameters, where the level of the actual can be arbitrary).
-- We can't use Valid_Conversion to perform this check because
-- in general the type of the allocator is unrelated to the type
-- of the access discriminant. Note that specialized checks are
-- needed for the cases of a constraint expression which is an
-- access attribute or an access discriminant.
if Nkind (Original_Node (E)) = N_Subtype_Indication
and then Ekind (Typ) /= E_Anonymous_Access_Type
then
Subtyp := Entity (Subtype_Mark (Original_Node (E)));
if Has_Discriminants (Subtyp) then
Discrim := First_Discriminant (Base_Type (Subtyp));
Constr := First (Constraints (Constraint (Original_Node (E))));
while Present (Discrim) and then Present (Constr) loop
if Ekind (Etype (Discrim)) = E_Anonymous_Access_Type then
if Nkind (Constr) = N_Discriminant_Association then
Disc_Exp := Original_Node (Expression (Constr));
else
Disc_Exp := Original_Node (Constr);
end if;
if Type_Access_Level (Etype (Disc_Exp))
> Type_Access_Level (Typ)
then
Error_Msg_N
("operand type has deeper level than allocator type",
Disc_Exp);
elsif Nkind (Disc_Exp) = N_Attribute_Reference
and then Get_Attribute_Id (Attribute_Name (Disc_Exp))
= Attribute_Access
and then Object_Access_Level (Prefix (Disc_Exp))
> Type_Access_Level (Typ)
then
Error_Msg_N
("prefix of attribute has deeper level than"
& " allocator type", Disc_Exp);
-- When the operand is an access discriminant the check
-- is against the level of the prefix object.
elsif Ekind (Etype (Disc_Exp)) = E_Anonymous_Access_Type
and then Nkind (Disc_Exp) = N_Selected_Component
and then Object_Access_Level (Prefix (Disc_Exp))
> Type_Access_Level (Typ)
then
Error_Msg_N
("access discriminant has deeper level than"
& " allocator type", Disc_Exp);
end if;
end if;
Next_Discriminant (Discrim);
Next (Constr);
end loop;
end if;
end if;
end if;
-- Check for allocation from an empty storage pool
if No_Pool_Assigned (Typ) then
declare
Loc : constant Source_Ptr := Sloc (N);
begin
Error_Msg_N ("?allocation from empty storage pool!", N);
Error_Msg_N ("?Storage_Error will be raised at run time!", N);
Insert_Action (N,
Make_Raise_Storage_Error (Loc));
end;
end if;
end Resolve_Allocator;
---------------------------
-- Resolve_Arithmetic_Op --
---------------------------
-- Used for resolving all arithmetic operators except exponentiation
procedure Resolve_Arithmetic_Op (N : Node_Id; Typ : Entity_Id) is
L : constant Node_Id := Left_Opnd (N);
R : constant Node_Id := Right_Opnd (N);
T : Entity_Id;
TL : Entity_Id := Base_Type (Etype (L));
TR : Entity_Id := Base_Type (Etype (R));
B_Typ : constant Entity_Id := Base_Type (Typ);
-- We do the resolution using the base type, because intermediate values
-- in expressions always are of the base type, not a subtype of it.
function Is_Integer_Or_Universal (N : Node_Id) return Boolean;
-- Return True iff given type is Integer or universal real/integer
procedure Set_Mixed_Mode_Operand (N : Node_Id; T : Entity_Id);
-- Choose type of integer literal in fixed-point operation to conform
-- to available fixed-point type. T is the type of the other operand,
-- which is needed to determine the expected type of N.
procedure Set_Operand_Type (N : Node_Id);
-- Set operand type to T if universal
function Universal_Interpretation (N : Node_Id) return Entity_Id;
-- Find universal type of operand, if any.
-----------------------------
-- Is_Integer_Or_Universal --
-----------------------------
function Is_Integer_Or_Universal (N : Node_Id) return Boolean is
T : Entity_Id;
Index : Interp_Index;
It : Interp;
begin
if not Is_Overloaded (N) then
T := Etype (N);
return Base_Type (T) = Base_Type (Standard_Integer)
or else T = Universal_Integer
or else T = Universal_Real;
else
Get_First_Interp (N, Index, It);
while Present (It.Typ) loop
if Base_Type (It.Typ) = Base_Type (Standard_Integer)
or else It.Typ = Universal_Integer
or else It.Typ = Universal_Real
then
return True;
end if;
Get_Next_Interp (Index, It);
end loop;
end if;
return False;
end Is_Integer_Or_Universal;
----------------------------
-- Set_Mixed_Mode_Operand --
----------------------------
procedure Set_Mixed_Mode_Operand (N : Node_Id; T : Entity_Id) is
Index : Interp_Index;
It : Interp;
begin
if Universal_Interpretation (N) = Universal_Integer then
-- A universal integer literal is resolved as standard integer
-- except in the case of a fixed-point result, where we leave
-- it as universal (to be handled by Exp_Fixd later on)
if Is_Fixed_Point_Type (T) then
Resolve (N, Universal_Integer);
else
Resolve (N, Standard_Integer);
end if;
elsif Universal_Interpretation (N) = Universal_Real
and then (T = Base_Type (Standard_Integer)
or else T = Universal_Integer
or else T = Universal_Real)
then
-- A universal real can appear in a fixed-type context. We resolve
-- the literal with that context, even though this might raise an
-- exception prematurely (the other operand may be zero).
Resolve (N, B_Typ);
elsif Etype (N) = Base_Type (Standard_Integer)
and then T = Universal_Real
and then Is_Overloaded (N)
then
-- Integer arg in mixed-mode operation. Resolve with universal
-- type, in case preference rule must be applied.
Resolve (N, Universal_Integer);
elsif Etype (N) = T
and then B_Typ /= Universal_Fixed
then
-- Not a mixed-mode operation. Resolve with context.
Resolve (N, B_Typ);
elsif Etype (N) = Any_Fixed then
-- N may itself be a mixed-mode operation, so use context type.
Resolve (N, B_Typ);
elsif Is_Fixed_Point_Type (T)
and then B_Typ = Universal_Fixed
and then Is_Overloaded (N)
then
-- Must be (fixed * fixed) operation, operand must have one
-- compatible interpretation.
Resolve (N, Any_Fixed);
elsif Is_Fixed_Point_Type (B_Typ)
and then (T = Universal_Real
or else Is_Fixed_Point_Type (T))
and then Is_Overloaded (N)
then
-- C * F(X) in a fixed context, where C is a real literal or a
-- fixed-point expression. F must have either a fixed type
-- interpretation or an integer interpretation, but not both.
Get_First_Interp (N, Index, It);
while Present (It.Typ) loop
if Base_Type (It.Typ) = Base_Type (Standard_Integer) then
if Analyzed (N) then
Error_Msg_N ("ambiguous operand in fixed operation", N);
else
Resolve (N, Standard_Integer);
end if;
elsif Is_Fixed_Point_Type (It.Typ) then
if Analyzed (N) then
Error_Msg_N ("ambiguous operand in fixed operation", N);
else
Resolve (N, It.Typ);
end if;
end if;
Get_Next_Interp (Index, It);
end loop;
-- Reanalyze the literal with the fixed type of the context.
if N = L then
Set_Analyzed (R, False);
Resolve (R, B_Typ);
else
Set_Analyzed (L, False);
Resolve (L, B_Typ);
end if;
else
Resolve (N, Etype (N));
end if;
end Set_Mixed_Mode_Operand;
----------------------
-- Set_Operand_Type --
----------------------
procedure Set_Operand_Type (N : Node_Id) is
begin
if Etype (N) = Universal_Integer
or else Etype (N) = Universal_Real
then
Set_Etype (N, T);
end if;
end Set_Operand_Type;
------------------------------
-- Universal_Interpretation --
------------------------------
function Universal_Interpretation (N : Node_Id) return Entity_Id is
Index : Interp_Index;
It : Interp;
begin
if not Is_Overloaded (N) then
if Etype (N) = Universal_Integer
or else Etype (N) = Universal_Real
then
return Etype (N);
else
return Empty;
end if;
else
Get_First_Interp (N, Index, It);
while Present (It.Typ) loop
if It.Typ = Universal_Integer
or else It.Typ = Universal_Real
then
return It.Typ;
end if;
Get_Next_Interp (Index, It);
end loop;
return Empty;
end if;
end Universal_Interpretation;
-- Start of processing for Resolve_Arithmetic_Op
begin
if Comes_From_Source (N)
and then Ekind (Entity (N)) = E_Function
and then Is_Imported (Entity (N))
and then Present (First_Rep_Item (Entity (N)))
then
Resolve_Intrinsic_Operator (N, Typ);
return;
-- Special-case for mixed-mode universal expressions or fixed point
-- type operation: each argument is resolved separately. The same
-- treatment is required if one of the operands of a fixed point
-- operation is universal real, since in this case we don't do a
-- conversion to a specific fixed-point type (instead the expander
-- takes care of the case).
elsif (B_Typ = Universal_Integer
or else B_Typ = Universal_Real)
and then Present (Universal_Interpretation (L))
and then Present (Universal_Interpretation (R))
then
Resolve (L, Universal_Interpretation (L));
Resolve (R, Universal_Interpretation (R));
Set_Etype (N, B_Typ);
elsif (B_Typ = Universal_Real
or else Etype (N) = Universal_Fixed
or else (Etype (N) = Any_Fixed
and then Is_Fixed_Point_Type (B_Typ))
or else (Is_Fixed_Point_Type (B_Typ)
and then (Is_Integer_Or_Universal (L)
or else
Is_Integer_Or_Universal (R))))
and then (Nkind (N) = N_Op_Multiply or else
Nkind (N) = N_Op_Divide)
then
if TL = Universal_Integer or else TR = Universal_Integer then
Check_For_Visible_Operator (N, B_Typ);
end if;
-- If context is a fixed type and one operand is integer, the
-- other is resolved with the type of the context.
if Is_Fixed_Point_Type (B_Typ)
and then (Base_Type (TL) = Base_Type (Standard_Integer)
or else TL = Universal_Integer)
then
Resolve (R, B_Typ);
Resolve (L, TL);
elsif Is_Fixed_Point_Type (B_Typ)
and then (Base_Type (TR) = Base_Type (Standard_Integer)
or else TR = Universal_Integer)
then
Resolve (L, B_Typ);
Resolve (R, TR);
else
Set_Mixed_Mode_Operand (L, TR);
Set_Mixed_Mode_Operand (R, TL);
end if;
if Etype (N) = Universal_Fixed
or else Etype (N) = Any_Fixed
then
if B_Typ = Universal_Fixed
and then Nkind (Parent (N)) /= N_Type_Conversion
and then Nkind (Parent (N)) /= N_Unchecked_Type_Conversion
then
Error_Msg_N
("type cannot be determined from context!", N);
Error_Msg_N
("\explicit conversion to result type required", N);
Set_Etype (L, Any_Type);
Set_Etype (R, Any_Type);
else
if Ada_83
and then Etype (N) = Universal_Fixed
and then Nkind (Parent (N)) /= N_Type_Conversion
and then Nkind (Parent (N)) /= N_Unchecked_Type_Conversion
then
Error_Msg_N
("(Ada 83) fixed-point operation " &
"needs explicit conversion",
N);
end if;
Set_Etype (N, B_Typ);
end if;
elsif Is_Fixed_Point_Type (B_Typ)
and then (Is_Integer_Or_Universal (L)
or else Nkind (L) = N_Real_Literal
or else Nkind (R) = N_Real_Literal
or else
Is_Integer_Or_Universal (R))
then
Set_Etype (N, B_Typ);
elsif Etype (N) = Any_Fixed then
-- If no previous errors, this is only possible if one operand
-- is overloaded and the context is universal. Resolve as such.
Set_Etype (N, B_Typ);
end if;
else
if (TL = Universal_Integer or else TL = Universal_Real)
and then (TR = Universal_Integer or else TR = Universal_Real)
then
Check_For_Visible_Operator (N, B_Typ);
end if;
-- If the context is Universal_Fixed and the operands are also
-- universal fixed, this is an error, unless there is only one
-- applicable fixed_point type (usually duration).
if B_Typ = Universal_Fixed
and then Etype (L) = Universal_Fixed
then
T := Unique_Fixed_Point_Type (N);
if T = Any_Type then
Set_Etype (N, T);
return;
else
Resolve (L, T);
Resolve (R, T);
end if;
else
Resolve (L, B_Typ);
Resolve (R, B_Typ);
end if;
-- If one of the arguments was resolved to a non-universal type.
-- label the result of the operation itself with the same type.
-- Do the same for the universal argument, if any.
T := Intersect_Types (L, R);
Set_Etype (N, Base_Type (T));
Set_Operand_Type (L);
Set_Operand_Type (R);
end if;
Generate_Operator_Reference (N);
Eval_Arithmetic_Op (N);
-- Set overflow and division checking bit. Much cleverer code needed
-- here eventually and perhaps the Resolve routines should be separated
-- for the various arithmetic operations, since they will need
-- different processing. ???
if Nkind (N) in N_Op then
if not Overflow_Checks_Suppressed (Etype (N)) then
Set_Do_Overflow_Check (N);
end if;
if (Nkind (N) = N_Op_Divide
or else Nkind (N) = N_Op_Rem
or else Nkind (N) = N_Op_Mod)
and then not Division_Checks_Suppressed (Etype (N))
then
Set_Do_Division_Check (N);
end if;
end if;
Check_Unset_Reference (L);
Check_Unset_Reference (R);
end Resolve_Arithmetic_Op;
------------------
-- Resolve_Call --
------------------
procedure Resolve_Call (N : Node_Id; Typ : Entity_Id) is
Loc : constant Source_Ptr := Sloc (N);
Subp : constant Node_Id := Name (N);
Nam : Entity_Id;
I : Interp_Index;
It : Interp;
Norm_OK : Boolean;
Scop : Entity_Id;
begin
-- The context imposes a unique interpretation with type Typ on
-- a procedure or function call. Find the entity of the subprogram
-- that yields the expected type, and propagate the corresponding
-- formal constraints on the actuals. The caller has established
-- that an interpretation exists, and emitted an error if not unique.
-- First deal with the case of a call to an access-to-subprogram,
-- dereference made explicit in Analyze_Call.
if Ekind (Etype (Subp)) = E_Subprogram_Type then
if not Is_Overloaded (Subp) then
Nam := Etype (Subp);
else
-- Find the interpretation whose type (a subprogram type)
-- has a return type that is compatible with the context.
-- Analysis of the node has established that one exists.
Get_First_Interp (Subp, I, It);
Nam := Empty;
while Present (It.Typ) loop
if Covers (Typ, Etype (It.Typ)) then
Nam := It.Typ;
exit;
end if;
Get_Next_Interp (I, It);
end loop;
if No (Nam) then
raise Program_Error;
end if;
end if;
-- If the prefix is not an entity, then resolve it
if not Is_Entity_Name (Subp) then
Resolve (Subp, Nam);
end if;
-- If this is a procedure call which is really an entry call, do
-- the conversion of the procedure call to an entry call. Protected
-- operations use the same circuitry because the name in the call
-- can be an arbitrary expression with special resolution rules.
elsif Nkind (Subp) = N_Selected_Component
or else Nkind (Subp) = N_Indexed_Component
or else (Is_Entity_Name (Subp)
and then Ekind (Entity (Subp)) = E_Entry)
then
Resolve_Entry_Call (N, Typ);
Check_Elab_Call (N);
return;
-- Normal subprogram call with name established in Resolve
elsif not (Is_Type (Entity (Subp))) then
Nam := Entity (Subp);
Set_Entity_With_Style_Check (Subp, Nam);
Generate_Reference (Nam, Subp);
-- Otherwise we must have the case of an overloaded call
else
pragma Assert (Is_Overloaded (Subp));
Nam := Empty; -- We know that it will be assigned in loop below.
Get_First_Interp (Subp, I, It);
while Present (It.Typ) loop
if Covers (Typ, It.Typ) then
Nam := It.Nam;
Set_Entity_With_Style_Check (Subp, Nam);
Generate_Reference (Nam, Subp);
exit;
end if;
Get_Next_Interp (I, It);
end loop;
end if;
-- Check that a call to Current_Task does not occur in an entry body
if Is_RTE (Nam, RE_Current_Task) then
declare
P : Node_Id;
begin
P := N;
loop
P := Parent (P);
exit when No (P);
if Nkind (P) = N_Entry_Body then
Error_Msg_NE
("& should not be used in entry body ('R'M C.7(17))",
N, Nam);
exit;
end if;
end loop;
end;
end if;
-- Check that a procedure call does not occur in the context
-- of the entry call statement of a conditional or timed
-- entry call. Note that the case of a call to a subprogram
-- renaming of an entry will also be rejected. The test
-- for N not being an N_Entry_Call_Statement is defensive,
-- covering the possibility that the processing of entry
-- calls might reach this point due to later modifications
-- of the code above.
if Nkind (Parent (N)) = N_Entry_Call_Alternative
and then Nkind (N) /= N_Entry_Call_Statement
and then Entry_Call_Statement (Parent (N)) = N
then
Error_Msg_N ("entry call required in select statement", N);
end if;
-- Freeze the subprogram name if not in default expression. Note
-- that we freeze procedure calls as well as function calls.
-- Procedure calls are not frozen according to the rules (RM
-- 13.14(14)) because it is impossible to have a procedure call to
-- a non-frozen procedure in pure Ada, but in the code that we
-- generate in the expander, this rule needs extending because we
-- can generate procedure calls that need freezing.
if Is_Entity_Name (Subp) and then not In_Default_Expression then
Freeze_Expression (Subp);
end if;
-- For a predefined operator, the type of the result is the type
-- imposed by context, except for a predefined operation on universal
-- fixed. Otherwise The type of the call is the type returned by the
-- subprogram being called.
if Is_Predefined_Op (Nam) then
if Etype (N) /= Universal_Fixed then
Set_Etype (N, Typ);
end if;
-- If the subprogram returns an array type, and the context
-- requires the component type of that array type, the node is
-- really an indexing of the parameterless call. Resolve as such.
elsif Needs_No_Actuals (Nam)
and then
((Is_Array_Type (Etype (Nam))
and then Covers (Typ, Component_Type (Etype (Nam))))
or else (Is_Access_Type (Etype (Nam))
and then Is_Array_Type (Designated_Type (Etype (Nam)))
and then
Covers (Typ,
Component_Type (Designated_Type (Etype (Nam))))))
then
declare
Index_Node : Node_Id;
begin
if Component_Type (Etype (Nam)) /= Any_Type then
Index_Node :=
Make_Indexed_Component (Loc,
Prefix =>
Make_Function_Call (Loc,
Name => New_Occurrence_Of (Nam, Loc)),
Expressions => Parameter_Associations (N));
-- Since we are correcting a node classification error made by
-- the parser, we call Replace rather than Rewrite.
Replace (N, Index_Node);
Set_Etype (Prefix (N), Etype (Nam));
Set_Etype (N, Typ);
Resolve_Indexed_Component (N, Typ);
Check_Elab_Call (Prefix (N));
end if;
return;
end;
else
Set_Etype (N, Etype (Nam));
end if;
-- In the case where the call is to an overloaded subprogram, Analyze
-- calls Normalize_Actuals once per overloaded subprogram. Therefore in
-- such a case Normalize_Actuals needs to be called once more to order
-- the actuals correctly. Otherwise the call will have the ordering
-- given by the last overloaded subprogram whether this is the correct
-- one being called or not.
if Is_Overloaded (Subp) then
Normalize_Actuals (N, Nam, False, Norm_OK);
pragma Assert (Norm_OK);
end if;
-- In any case, call is fully resolved now. Reset Overload flag, to
-- prevent subsequent overload resolution if node is analyzed again
Set_Is_Overloaded (Subp, False);
Set_Is_Overloaded (N, False);
-- If we are calling the current subprogram from immediately within
-- its body, then that is the case where we can sometimes detect
-- cases of infinite recursion statically. Do not try this in case
-- restriction No_Recursion is in effect anyway.
Scop := Current_Scope;
if Nam = Scop
and then not Restrictions (No_Recursion)
and then Check_Infinite_Recursion (N)
then
-- Here we detected and flagged an infinite recursion, so we do
-- not need to test the case below for further warnings.
null;
-- If call is to immediately containing subprogram, then check for
-- the case of a possible run-time detectable infinite recursion.
else
while Scop /= Standard_Standard loop
if Nam = Scop then
-- Although in general recursion is not statically checkable,
-- the case of calling an immediately containing subprogram
-- is easy to catch.
Check_Restriction (No_Recursion, N);
-- If the recursive call is to a parameterless procedure, then
-- even if we can't statically detect infinite recursion, this
-- is pretty suspicious, and we output a warning. Furthermore,
-- we will try later to detect some cases here at run time by
-- expanding checking code (see Detect_Infinite_Recursion in
-- package Exp_Ch6).
-- If the recursive call is within a handler we do not emit a
-- warning, because this is a common idiom: loop until input
-- is correct, catch illegal input in handler and restart.
if No (First_Formal (Nam))
and then Etype (Nam) = Standard_Void_Type
and then not Error_Posted (N)
and then Nkind (Parent (N)) /= N_Exception_Handler
then
Set_Has_Recursive_Call (Nam);
Error_Msg_N ("possible infinite recursion?", N);
Error_Msg_N ("Storage_Error may be raised at run time?", N);
end if;
exit;
end if;
Scop := Scope (Scop);
end loop;
end if;
-- If subprogram name is a predefined operator, it was given in
-- functional notation. Replace call node with operator node, so
-- that actuals can be resolved appropriately.
if Is_Predefined_Op (Nam) or else Ekind (Nam) = E_Operator then
Make_Call_Into_Operator (N, Typ, Entity (Name (N)));
return;
elsif Present (Alias (Nam))
and then Is_Predefined_Op (Alias (Nam))
then
Resolve_Actuals (N, Nam);
Make_Call_Into_Operator (N, Typ, Alias (Nam));
return;
end if;
-- Create a transient scope if the resulting type requires it.
-- There are 3 notable exceptions: in init_procs, the transient scope
-- overhead is not needed and even incorrect due to the actual expansion
-- of adjust calls; the second case is enumeration literal pseudo calls,
-- the other case is intrinsic subprograms (Unchecked_Conversion and
-- source information functions) that do not use the secondary stack
-- even though the return type is unconstrained.
-- If this is an initialization call for a type whose initialization
-- uses the secondary stack, we also need to create a transient scope
-- for it, precisely because we will not do it within the init_proc
-- itself.
if Expander_Active
and then Is_Type (Etype (Nam))
and then Requires_Transient_Scope (Etype (Nam))
and then Ekind (Nam) /= E_Enumeration_Literal
and then not Within_Init_Proc
and then not Is_Intrinsic_Subprogram (Nam)
then
Establish_Transient_Scope
(N, Sec_Stack => not Functions_Return_By_DSP_On_Target);
elsif Chars (Nam) = Name_uInit_Proc
and then not Within_Init_Proc
then
Check_Initialization_Call (N, Nam);
end if;
-- A protected function cannot be called within the definition of the
-- enclosing protected type.
if Is_Protected_Type (Scope (Nam))
and then In_Open_Scopes (Scope (Nam))
and then not Has_Completion (Scope (Nam))
then
Error_Msg_NE
("& cannot be called before end of protected definition", N, Nam);
end if;
-- Propagate interpretation to actuals, and add default expressions
-- where needed.
if Present (First_Formal (Nam)) then
Resolve_Actuals (N, Nam);
-- Overloaded literals are rewritten as function calls, for
-- purpose of resolution. After resolution, we can replace
-- the call with the literal itself.
elsif Ekind (Nam) = E_Enumeration_Literal then
Copy_Node (Subp, N);
Resolve_Entity_Name (N, Typ);
-- Avoid validation, since it is a static function call.
return;
end if;
-- If the subprogram is a primitive operation, check whether or not
-- it is a correct dispatching call.
if Is_Overloadable (Nam)
and then Is_Dispatching_Operation (Nam)
then
Check_Dispatching_Call (N);
-- If the subprogram is abstract, check that the call has a
-- controlling argument (i.e. is dispatching) or is disptaching on
-- result
if Is_Abstract (Nam)
and then No (Controlling_Argument (N))
and then not Is_Class_Wide_Type (Typ)
and then not Is_Tag_Indeterminate (N)
then
Error_Msg_N ("call to abstract subprogram must be dispatching", N);
end if;
elsif Is_Abstract (Nam)
and then not In_Instance
then
Error_Msg_NE ("cannot call abstract subprogram &!", N, Nam);
end if;
if Is_Intrinsic_Subprogram (Nam) then
Check_Intrinsic_Call (N);
end if;
-- If we fall through we definitely have a non-static call
Check_Elab_Call (N);
end Resolve_Call;
-------------------------------
-- Resolve_Character_Literal --
-------------------------------
procedure Resolve_Character_Literal (N : Node_Id; Typ : Entity_Id) is
B_Typ : constant Entity_Id := Base_Type (Typ);
C : Entity_Id;
begin
-- Verify that the character does belong to the type of the context
Set_Etype (N, B_Typ);
Eval_Character_Literal (N);
-- Wide_Character literals must always be defined, since the set of
-- wide character literals is complete, i.e. if a character literal
-- is accepted by the parser, then it is OK for wide character.
if Root_Type (B_Typ) = Standard_Wide_Character then
return;
-- Always accept character literal for type Any_Character, which
-- occurs in error situations and in comparisons of literals, both
-- of which should accept all literals.
elsif B_Typ = Any_Character then
return;
-- For Standard.Character or a type derived from it, check that
-- the literal is in range
elsif Root_Type (B_Typ) = Standard_Character then
if In_Character_Range (Char_Literal_Value (N)) then
return;
end if;
-- If the entity is already set, this has already been resolved in
-- a generic context, or comes from expansion. Nothing else to do.
elsif Present (Entity (N)) then
return;
-- Otherwise we have a user defined character type, and we can use
-- the standard visibility mechanisms to locate the referenced entity
else
C := Current_Entity (N);
while Present (C) loop
if Etype (C) = B_Typ then
Set_Entity_With_Style_Check (N, C);
Generate_Reference (C, N);
return;
end if;
C := Homonym (C);
end loop;
end if;
-- If we fall through, then the literal does not match any of the
-- entries of the enumeration type. This isn't just a constraint
-- error situation, it is an illegality (see RM 4.2).
Error_Msg_NE
("character not defined for }", N, First_Subtype (B_Typ));
end Resolve_Character_Literal;
---------------------------
-- Resolve_Comparison_Op --
---------------------------
-- Context requires a boolean type, and plays no role in resolution.
-- Processing identical to that for equality operators.
procedure Resolve_Comparison_Op (N : Node_Id; Typ : Entity_Id) is
L : constant Node_Id := Left_Opnd (N);
R : constant Node_Id := Right_Opnd (N);
T : Entity_Id;
begin
-- If this is an intrinsic operation which is not predefined, use
-- the types of its declared arguments to resolve the possibly
-- overloaded operands. Otherwise the operands are unambiguous and
-- specify the expected type.
if Scope (Entity (N)) /= Standard_Standard then
T := Etype (First_Entity (Entity (N)));
else
T := Find_Unique_Type (L, R);
if T = Any_Fixed then
T := Unique_Fixed_Point_Type (L);
end if;
end if;
Set_Etype (N, Typ);
Generate_Reference (T, N, ' ');
if T /= Any_Type then
if T = Any_String
or else T = Any_Composite
or else T = Any_Character
then
if T = Any_Character then
Ambiguous_Character (L);
else
Error_Msg_N ("ambiguous operands for comparison", N);
end if;
Set_Etype (N, Any_Type);
return;
else
if Comes_From_Source (N)
and then Has_Unchecked_Union (T)
then
Error_Msg_N
("cannot compare Unchecked_Union values", N);
end if;
Resolve (L, T);
Resolve (R, T);
Check_Unset_Reference (L);
Check_Unset_Reference (R);
Generate_Operator_Reference (N);
Eval_Relational_Op (N);
end if;
end if;
end Resolve_Comparison_Op;
------------------------------------
-- Resolve_Conditional_Expression --
------------------------------------
procedure Resolve_Conditional_Expression (N : Node_Id; Typ : Entity_Id) is
Condition : constant Node_Id := First (Expressions (N));
Then_Expr : constant Node_Id := Next (Condition);
Else_Expr : constant Node_Id := Next (Then_Expr);
begin
Resolve (Condition, Standard_Boolean);
Resolve (Then_Expr, Typ);
Resolve (Else_Expr, Typ);
Set_Etype (N, Typ);
Eval_Conditional_Expression (N);
end Resolve_Conditional_Expression;
-----------------------------------------
-- Resolve_Discrete_Subtype_Indication --
-----------------------------------------
procedure Resolve_Discrete_Subtype_Indication
(N : Node_Id;
Typ : Entity_Id)
is
R : Node_Id;
S : Entity_Id;
begin
Analyze (Subtype_Mark (N));
S := Entity (Subtype_Mark (N));
if Nkind (Constraint (N)) /= N_Range_Constraint then
Error_Msg_N ("expect range constraint for discrete type", N);
Set_Etype (N, Any_Type);
else
R := Range_Expression (Constraint (N));
if R = Error then
return;
end if;
Analyze (R);
if Base_Type (S) /= Base_Type (Typ) then
Error_Msg_NE
("expect subtype of }", N, First_Subtype (Typ));
-- Rewrite the constraint as a range of Typ
-- to allow compilation to proceed further.
Set_Etype (N, Typ);
Rewrite (Low_Bound (R),
Make_Attribute_Reference (Sloc (Low_Bound (R)),
Prefix => New_Occurrence_Of (Typ, Sloc (R)),
Attribute_Name => Name_First));
Rewrite (High_Bound (R),
Make_Attribute_Reference (Sloc (High_Bound (R)),
Prefix => New_Occurrence_Of (Typ, Sloc (R)),
Attribute_Name => Name_First));
else
Resolve (R, Typ);
Set_Etype (N, Etype (R));
-- Additionally, we must check that the bounds are compatible
-- with the given subtype, which might be different from the
-- type of the context.
Apply_Range_Check (R, S);
-- ??? If the above check statically detects a Constraint_Error
-- it replaces the offending bound(s) of the range R with a
-- Constraint_Error node. When the itype which uses these bounds
-- is frozen the resulting call to Duplicate_Subexpr generates
-- a new temporary for the bounds.
-- Unfortunately there are other itypes that are also made depend
-- on these bounds, so when Duplicate_Subexpr is called they get
-- a forward reference to the newly created temporaries and Gigi
-- aborts on such forward references. This is probably sign of a
-- more fundamental problem somewhere else in either the order of
-- itype freezing or the way certain itypes are constructed.
-- To get around this problem we call Remove_Side_Effects right
-- away if either bounds of R are a Constraint_Error.
declare
L : Node_Id := Low_Bound (R);
H : Node_Id := High_Bound (R);
begin
if Nkind (L) = N_Raise_Constraint_Error then
Remove_Side_Effects (L);
end if;
if Nkind (H) = N_Raise_Constraint_Error then
Remove_Side_Effects (H);
end if;
end;
Check_Unset_Reference (Low_Bound (R));
Check_Unset_Reference (High_Bound (R));
end if;
end if;
end Resolve_Discrete_Subtype_Indication;
-------------------------
-- Resolve_Entity_Name --
-------------------------
-- Used to resolve identifiers and expanded names
procedure Resolve_Entity_Name (N : Node_Id; Typ : Entity_Id) is
E : constant Entity_Id := Entity (N);
begin
-- Replace named numbers by corresponding literals. Note that this is
-- the one case where Resolve_Entity_Name must reset the Etype, since
-- it is currently marked as universal.
if Ekind (E) = E_Named_Integer then
Set_Etype (N, Typ);
Eval_Named_Integer (N);
elsif Ekind (E) = E_Named_Real then
Set_Etype (N, Typ);
Eval_Named_Real (N);
-- Allow use of subtype only if it is a concurrent type where we are
-- currently inside the body. This will eventually be expanded
-- into a call to Self (for tasks) or _object (for protected
-- objects). Any other use of a subtype is invalid.
elsif Is_Type (E) then
if Is_Concurrent_Type (E)
and then In_Open_Scopes (E)
then
null;
else
Error_Msg_N
("Invalid use of subtype mark in expression or call", N);
end if;
-- Check discriminant use if entity is discriminant in current scope,
-- i.e. discriminant of record or concurrent type currently being
-- analyzed. Uses in corresponding body are unrestricted.
elsif Ekind (E) = E_Discriminant
and then Scope (E) = Current_Scope
and then not Has_Completion (Current_Scope)
then
Check_Discriminant_Use (N);
-- A parameterless generic function cannot appear in a context that
-- requires resolution.
elsif Ekind (E) = E_Generic_Function then
Error_Msg_N ("illegal use of generic function", N);
elsif Ekind (E) = E_Out_Parameter
and then Ada_83
and then (Nkind (Parent (N)) in N_Op
or else (Nkind (Parent (N)) = N_Assignment_Statement
and then N = Expression (Parent (N)))
or else Nkind (Parent (N)) = N_Explicit_Dereference)
then
Error_Msg_N ("(Ada 83) illegal reading of out parameter", N);
-- In all other cases, just do the possible static evaluation
else
-- A deferred constant that appears in an expression must have
-- a completion, unless it has been removed by in-place expansion
-- of an aggregate.
if Ekind (E) = E_Constant
and then Comes_From_Source (E)
and then No (Constant_Value (E))
and then Is_Frozen (Etype (E))
and then not In_Default_Expression
and then not Is_Imported (E)
then
if No_Initialization (Parent (E))
or else (Present (Full_View (E))
and then No_Initialization (Parent (Full_View (E))))
then
null;
else
Error_Msg_N (
"deferred constant is frozen before completion", N);
end if;
end if;
Eval_Entity_Name (N);
end if;
end Resolve_Entity_Name;
-------------------
-- Resolve_Entry --
-------------------
procedure Resolve_Entry (Entry_Name : Node_Id) is
Loc : constant Source_Ptr := Sloc (Entry_Name);
Nam : Entity_Id;
New_N : Node_Id;
S : Entity_Id;
Tsk : Entity_Id;
E_Name : Node_Id;
Index : Node_Id;
function Actual_Index_Type (E : Entity_Id) return Entity_Id;
-- If the bounds of the entry family being called depend on task
-- discriminants, build a new index subtype where a discriminant is
-- replaced with the value of the discriminant of the target task.
-- The target task is the prefix of the entry name in the call.
-----------------------
-- Actual_Index_Type --
-----------------------
function Actual_Index_Type (E : Entity_Id) return Entity_Id is
Typ : Entity_Id := Entry_Index_Type (E);
Tsk : Entity_Id := Scope (E);
Lo : Node_Id := Type_Low_Bound (Typ);
Hi : Node_Id := Type_High_Bound (Typ);
New_T : Entity_Id;
function Actual_Discriminant_Ref (Bound : Node_Id) return Node_Id;
-- If the bound is given by a discriminant, replace with a reference
-- to the discriminant of the same name in the target task.
-- If the entry name is the target of a requeue statement and the
-- entry is in the current protected object, the bound to be used
-- is the discriminal of the object (see apply_range_checks for
-- details of the transformation).
-----------------------------
-- Actual_Discriminant_Ref --
-----------------------------
function Actual_Discriminant_Ref (Bound : Node_Id) return Node_Id is
Typ : Entity_Id := Etype (Bound);
Ref : Node_Id;
begin
Remove_Side_Effects (Bound);
if not Is_Entity_Name (Bound)
or else Ekind (Entity (Bound)) /= E_Discriminant
then
return Bound;
elsif Is_Protected_Type (Tsk)
and then In_Open_Scopes (Tsk)
and then Nkind (Parent (Entry_Name)) = N_Requeue_Statement
then
return New_Occurrence_Of (Discriminal (Entity (Bound)), Loc);
else
Ref :=
Make_Selected_Component (Loc,
Prefix => New_Copy_Tree (Prefix (Prefix (Entry_Name))),
Selector_Name => New_Occurrence_Of (Entity (Bound), Loc));
Analyze (Ref);
Resolve (Ref, Typ);
return Ref;
end if;
end Actual_Discriminant_Ref;
-- Start of processing for Actual_Index_Type
begin
if not Has_Discriminants (Tsk)
or else (not Is_Entity_Name (Lo)
and then not Is_Entity_Name (Hi))
then
return Entry_Index_Type (E);
else
New_T := Create_Itype (Ekind (Typ), Parent (Entry_Name));
Set_Etype (New_T, Base_Type (Typ));
Set_Size_Info (New_T, Typ);
Set_RM_Size (New_T, RM_Size (Typ));
Set_Scalar_Range (New_T,
Make_Range (Sloc (Entry_Name),
Low_Bound => Actual_Discriminant_Ref (Lo),
High_Bound => Actual_Discriminant_Ref (Hi)));
return New_T;
end if;
end Actual_Index_Type;
-- Start of processing of Resolve_Entry
begin
-- Find name of entry being called, and resolve prefix of name
-- with its own type. The prefix can be overloaded, and the name
-- and signature of the entry must be taken into account.
if Nkind (Entry_Name) = N_Indexed_Component then
-- Case of dealing with entry family within the current tasks
E_Name := Prefix (Entry_Name);
else
E_Name := Entry_Name;
end if;
if Is_Entity_Name (E_Name) then
-- Entry call to an entry (or entry family) in the current task.
-- This is legal even though the task will deadlock. Rewrite as
-- call to current task.
-- This can also be a call to an entry in an enclosing task.
-- If this is a single task, we have to retrieve its name,
-- because the scope of the entry is the task type, not the
-- object. If the enclosing task is a task type, the identity
-- of the task is given by its own self variable.
-- Finally this can be a requeue on an entry of the same task
-- or protected object.
S := Scope (Entity (E_Name));
for J in reverse 0 .. Scope_Stack.Last loop
if Is_Task_Type (Scope_Stack.Table (J).Entity)
and then not Comes_From_Source (S)
then
-- S is an enclosing task or protected object. The concurrent
-- declaration has been converted into a type declaration, and
-- the object itself has an object declaration that follows
-- the type in the same declarative part.
Tsk := Next_Entity (S);
while Etype (Tsk) /= S loop
Next_Entity (Tsk);
end loop;
S := Tsk;
exit;
elsif S = Scope_Stack.Table (J).Entity then
-- Call to current task. Will be transformed into call to Self
exit;
end if;
end loop;
New_N :=
Make_Selected_Component (Loc,
Prefix => New_Occurrence_Of (S, Loc),
Selector_Name =>
New_Occurrence_Of (Entity (E_Name), Loc));
Rewrite (E_Name, New_N);
Analyze (E_Name);
elsif Nkind (Entry_Name) = N_Selected_Component
and then Is_Overloaded (Prefix (Entry_Name))
then
-- Use the entry name (which must be unique at this point) to
-- find the prefix that returns the corresponding task type or
-- protected type.
declare
Pref : Node_Id := Prefix (Entry_Name);
I : Interp_Index;
It : Interp;
Ent : Entity_Id := Entity (Selector_Name (Entry_Name));
begin
Get_First_Interp (Pref, I, It);
while Present (It.Typ) loop
if Scope (Ent) = It.Typ then
Set_Etype (Pref, It.Typ);
exit;
end if;
Get_Next_Interp (I, It);
end loop;
end;
end if;
if Nkind (Entry_Name) = N_Selected_Component then
Resolve (Prefix (Entry_Name), Etype (Prefix (Entry_Name)));
else pragma Assert (Nkind (Entry_Name) = N_Indexed_Component);
Nam := Entity (Selector_Name (Prefix (Entry_Name)));
Resolve (Prefix (Prefix (Entry_Name)),
Etype (Prefix (Prefix (Entry_Name))));
Index := First (Expressions (Entry_Name));
Resolve (Index, Entry_Index_Type (Nam));
-- Up to this point the expression could have been the actual
-- in a simple entry call, and be given by a named association.
if Nkind (Index) = N_Parameter_Association then
Error_Msg_N ("expect expression for entry index", Index);
else
Apply_Range_Check (Index, Actual_Index_Type (Nam));
end if;
end if;
end Resolve_Entry;
------------------------
-- Resolve_Entry_Call --
------------------------
procedure Resolve_Entry_Call (N : Node_Id; Typ : Entity_Id) is
Entry_Name : constant Node_Id := Name (N);
Loc : constant Source_Ptr := Sloc (Entry_Name);
Actuals : List_Id;
First_Named : Node_Id;
Nam : Entity_Id;
Norm_OK : Boolean;
Obj : Node_Id;
Was_Over : Boolean;
begin
-- Processing of the name is similar for entry calls and protected
-- operation calls. Once the entity is determined, we can complete
-- the resolution of the actuals.
-- The selector may be overloaded, in the case of a protected object
-- with overloaded functions. The type of the context is used for
-- resolution.
if Nkind (Entry_Name) = N_Selected_Component
and then Is_Overloaded (Selector_Name (Entry_Name))
and then Typ /= Standard_Void_Type
then
declare
I : Interp_Index;
It : Interp;
begin
Get_First_Interp (Selector_Name (Entry_Name), I, It);
while Present (It.Typ) loop
if Covers (Typ, It.Typ) then
Set_Entity (Selector_Name (Entry_Name), It.Nam);
Set_Etype (Entry_Name, It.Typ);
Generate_Reference (It.Typ, N, ' ');
end if;
Get_Next_Interp (I, It);
end loop;
end;
end if;
Resolve_Entry (Entry_Name);
if Nkind (Entry_Name) = N_Selected_Component then
-- Simple entry call.
Nam := Entity (Selector_Name (Entry_Name));
Obj := Prefix (Entry_Name);
Was_Over := Is_Overloaded (Selector_Name (Entry_Name));
else pragma Assert (Nkind (Entry_Name) = N_Indexed_Component);
-- Call to member of entry family.
Nam := Entity (Selector_Name (Prefix (Entry_Name)));
Obj := Prefix (Prefix (Entry_Name));
Was_Over := Is_Overloaded (Selector_Name (Prefix (Entry_Name)));
end if;
-- Use context type to disambiguate a protected function that can be
-- called without actuals and that returns an array type, and where
-- the argument list may be an indexing of the returned value.
if Ekind (Nam) = E_Function
and then Needs_No_Actuals (Nam)
and then Present (Parameter_Associations (N))
and then
((Is_Array_Type (Etype (Nam))
and then Covers (Typ, Component_Type (Etype (Nam))))
or else (Is_Access_Type (Etype (Nam))
and then Is_Array_Type (Designated_Type (Etype (Nam)))
and then Covers (Typ,
Component_Type (Designated_Type (Etype (Nam))))))
then
declare
Index_Node : Node_Id;
begin
Index_Node :=
Make_Indexed_Component (Loc,
Prefix =>
Make_Function_Call (Loc,
Name => Relocate_Node (Entry_Name)),
Expressions => Parameter_Associations (N));
-- Since we are correcting a node classification error made by
-- the parser, we call Replace rather than Rewrite.
Replace (N, Index_Node);
Set_Etype (Prefix (N), Etype (Nam));
Set_Etype (N, Typ);
Resolve_Indexed_Component (N, Typ);
return;
end;
end if;
-- The operation name may have been overloaded. Order the actuals
-- according to the formals of the resolved entity.
if Was_Over then
Normalize_Actuals (N, Nam, False, Norm_OK);
pragma Assert (Norm_OK);
end if;
Resolve_Actuals (N, Nam);
Generate_Reference (Nam, Entry_Name);
if Ekind (Nam) = E_Entry
or else Ekind (Nam) = E_Entry_Family
then
Check_Potentially_Blocking_Operation (N);
end if;
-- Verify that a procedure call cannot masquerade as an entry
-- call where an entry call is expected.
if Ekind (Nam) = E_Procedure then
if Nkind (Parent (N)) = N_Entry_Call_Alternative
and then N = Entry_Call_Statement (Parent (N))
then
Error_Msg_N ("entry call required in select statement", N);
elsif Nkind (Parent (N)) = N_Triggering_Alternative
and then N = Triggering_Statement (Parent (N))
then
Error_Msg_N ("triggering statement cannot be procedure call", N);
elsif Ekind (Scope (Nam)) = E_Task_Type
and then not In_Open_Scopes (Scope (Nam))
then
Error_Msg_N ("Task has no entry with this name", Entry_Name);
end if;
end if;
-- After resolution, entry calls and protected procedure calls
-- are changed into entry calls, for expansion. The structure
-- of the node does not change, so it can safely be done in place.
-- Protected function calls must keep their structure because they
-- are subexpressions.
if Ekind (Nam) /= E_Function then
-- A protected operation that is not a function may modify the
-- corresponding object, and cannot apply to a constant.
-- If this is an internal call, the prefix is the type itself.
if Is_Protected_Type (Scope (Nam))
and then not Is_Variable (Obj)
and then (not Is_Entity_Name (Obj)
or else not Is_Type (Entity (Obj)))
then
Error_Msg_N
("prefix of protected procedure or entry call must be variable",
Entry_Name);
end if;
Actuals := Parameter_Associations (N);
First_Named := First_Named_Actual (N);
Rewrite (N,
Make_Entry_Call_Statement (Loc,
Name => Entry_Name,
Parameter_Associations => Actuals));
Set_First_Named_Actual (N, First_Named);
Set_Analyzed (N, True);
-- Protected functions can return on the secondary stack, in which
-- case we must trigger the transient scope mechanism
elsif Expander_Active
and then Requires_Transient_Scope (Etype (Nam))
then
Establish_Transient_Scope (N,
Sec_Stack => not Functions_Return_By_DSP_On_Target);
end if;
end Resolve_Entry_Call;
-------------------------
-- Resolve_Equality_Op --
-------------------------
-- Both arguments must have the same type, and the boolean context
-- does not participate in the resolution. The first pass verifies
-- that the interpretation is not ambiguous, and the type of the left
-- argument is correctly set, or is Any_Type in case of ambiguity.
-- If both arguments are strings or aggregates, allocators, or Null,
-- they are ambiguous even though they carry a single (universal) type.
-- Diagnose this case here.
procedure Resolve_Equality_Op (N : Node_Id; Typ : Entity_Id) is
L : constant Node_Id := Left_Opnd (N);
R : constant Node_Id := Right_Opnd (N);
T : Entity_Id := Find_Unique_Type (L, R);
function Find_Unique_Access_Type return Entity_Id;
-- In the case of allocators, make a last-ditch attempt to find a single
-- access type with the right designated type. This is semantically
-- dubious, and of no interest to any real code, but c48008a makes it
-- all worthwhile.
-----------------------------
-- Find_Unique_Access_Type --
-----------------------------
function Find_Unique_Access_Type return Entity_Id is
Acc : Entity_Id;
E : Entity_Id;
S : Entity_Id := Current_Scope;
begin
if Ekind (Etype (R)) = E_Allocator_Type then
Acc := Designated_Type (Etype (R));
elsif Ekind (Etype (L)) = E_Allocator_Type then
Acc := Designated_Type (Etype (L));
else
return Empty;
end if;
while S /= Standard_Standard loop
E := First_Entity (S);
while Present (E) loop
if Is_Type (E)
and then Is_Access_Type (E)
and then Ekind (E) /= E_Allocator_Type
and then Designated_Type (E) = Base_Type (Acc)
then
return E;
end if;
Next_Entity (E);
end loop;
S := Scope (S);
end loop;
return Empty;
end Find_Unique_Access_Type;
-- Start of processing for Resolve_Equality_Op
begin
Set_Etype (N, Base_Type (Typ));
Generate_Reference (T, N, ' ');
if T = Any_Fixed then
T := Unique_Fixed_Point_Type (L);
end if;
if T /= Any_Type then
if T = Any_String
or else T = Any_Composite
or else T = Any_Character
then
if T = Any_Character then
Ambiguous_Character (L);
else
Error_Msg_N ("ambiguous operands for equality", N);
end if;
Set_Etype (N, Any_Type);
return;
elsif T = Any_Access
or else Ekind (T) = E_Allocator_Type
then
T := Find_Unique_Access_Type;
if No (T) then
Error_Msg_N ("ambiguous operands for equality", N);
Set_Etype (N, Any_Type);
return;
end if;
end if;
if Comes_From_Source (N)
and then Has_Unchecked_Union (T)
then
Error_Msg_N
("cannot compare Unchecked_Union values", N);
end if;
Resolve (L, T);
Resolve (R, T);
Check_Unset_Reference (L);
Check_Unset_Reference (R);
Generate_Operator_Reference (N);
-- If this is an inequality, it may be the implicit inequality
-- created for a user-defined operation, in which case the corres-
-- ponding equality operation is not intrinsic, and the operation
-- cannot be constant-folded. Else fold.
if Nkind (N) = N_Op_Eq
or else Comes_From_Source (Entity (N))
or else Ekind (Entity (N)) = E_Operator
or else Is_Intrinsic_Subprogram
(Corresponding_Equality (Entity (N)))
then
Eval_Relational_Op (N);
elsif Nkind (N) = N_Op_Ne
and then Is_Abstract (Entity (N))
then
Error_Msg_NE ("cannot call abstract subprogram &!", N, Entity (N));
end if;
end if;
end Resolve_Equality_Op;
----------------------------------
-- Resolve_Explicit_Dereference --
----------------------------------
procedure Resolve_Explicit_Dereference (N : Node_Id; Typ : Entity_Id) is
P : constant Node_Id := Prefix (N);
I : Interp_Index;
It : Interp;
begin
-- Now that we know the type, check that this is not a
-- dereference of an uncompleted type. Note that this
-- is not entirely correct, because dereferences of
-- private types are legal in default expressions.
-- This consideration also applies to similar checks
-- for allocators, qualified expressions, and type
-- conversions. ???
Check_Fully_Declared (Typ, N);
if Is_Overloaded (P) then
-- Use the context type to select the prefix that has the
-- correct designated type.
Get_First_Interp (P, I, It);
while Present (It.Typ) loop
exit when Is_Access_Type (It.Typ)
and then Covers (Typ, Designated_Type (It.Typ));
Get_Next_Interp (I, It);
end loop;
Resolve (P, It.Typ);
Set_Etype (N, Designated_Type (It.Typ));
else
Resolve (P, Etype (P));
end if;
if Is_Access_Type (Etype (P)) then
Apply_Access_Check (N);
end if;
-- If the designated type is a packed unconstrained array type,
-- and the explicit dereference is not in the context of an
-- attribute reference, then we must compute and set the actual
-- subtype, since it is needed by Gigi. The reason we exclude
-- the attribute case is that this is handled fine by Gigi, and
-- in fact we use such attributes to build the actual subtype.
-- We also exclude generated code (which builds actual subtypes
-- directly if they are needed).
if Is_Array_Type (Etype (N))
and then Is_Packed (Etype (N))
and then not Is_Constrained (Etype (N))
and then Nkind (Parent (N)) /= N_Attribute_Reference
and then Comes_From_Source (N)
then
Set_Etype (N, Get_Actual_Subtype (N));
end if;
-- Note: there is no Eval processing required for an explicit
-- deference, because the type is known to be an allocators, and
-- allocator expressions can never be static.
end Resolve_Explicit_Dereference;
-------------------------------
-- Resolve_Indexed_Component --
-------------------------------
procedure Resolve_Indexed_Component (N : Node_Id; Typ : Entity_Id) is
Name : constant Node_Id := Prefix (N);
Expr : Node_Id;
Array_Type : Entity_Id := Empty; -- to prevent junk warning
Index : Node_Id;
begin
if Is_Overloaded (Name) then
-- Use the context type to select the prefix that yields the
-- correct component type.
declare
I : Interp_Index;
It : Interp;
I1 : Interp_Index := 0;
P : constant Node_Id := Prefix (N);
Found : Boolean := False;
begin
Get_First_Interp (P, I, It);
while Present (It.Typ) loop
if (Is_Array_Type (It.Typ)
and then Covers (Typ, Component_Type (It.Typ)))
or else (Is_Access_Type (It.Typ)
and then Is_Array_Type (Designated_Type (It.Typ))
and then Covers
(Typ, Component_Type (Designated_Type (It.Typ))))
then
if Found then
It := Disambiguate (P, I1, I, Any_Type);
if It = No_Interp then
Error_Msg_N ("ambiguous prefix for indexing", N);
Set_Etype (N, Typ);
return;
else
Found := True;
Array_Type := It.Typ;
I1 := I;
end if;
else
Found := True;
Array_Type := It.Typ;
I1 := I;
end if;
end if;
Get_Next_Interp (I, It);
end loop;
end;
else
Array_Type := Etype (Name);
end if;
Resolve (Name, Array_Type);
Array_Type := Get_Actual_Subtype_If_Available (Name);
-- If prefix is access type, dereference to get real array type.
-- Note: we do not apply an access check because the expander always
-- introduces an explicit dereference, and the check will happen there.
if Is_Access_Type (Array_Type) then
Array_Type := Designated_Type (Array_Type);
end if;
-- If name was overloaded, set component type correctly now.
Set_Etype (N, Component_Type (Array_Type));
Index := First_Index (Array_Type);
Expr := First (Expressions (N));
-- The prefix may have resolved to a string literal, in which case
-- its etype has a special representation. This is only possible
-- currently if the prefix is a static concatenation, written in
-- functional notation.
if Ekind (Array_Type) = E_String_Literal_Subtype then
Resolve (Expr, Standard_Positive);
else
while Present (Index) and Present (Expr) loop
Resolve (Expr, Etype (Index));
Check_Unset_Reference (Expr);
if Is_Scalar_Type (Etype (Expr)) then
Apply_Scalar_Range_Check (Expr, Etype (Index));
else
Apply_Range_Check (Expr, Get_Actual_Subtype (Index));
end if;
Next_Index (Index);
Next (Expr);
end loop;
end if;
Eval_Indexed_Component (N);
end Resolve_Indexed_Component;
-----------------------------
-- Resolve_Integer_Literal --
-----------------------------
procedure Resolve_Integer_Literal (N : Node_Id; Typ : Entity_Id) is
begin
Set_Etype (N, Typ);
Eval_Integer_Literal (N);
end Resolve_Integer_Literal;
---------------------------------
-- Resolve_Intrinsic_Operator --
---------------------------------
procedure Resolve_Intrinsic_Operator (N : Node_Id; Typ : Entity_Id) is
Op : Entity_Id;
Arg1 : Node_Id := Left_Opnd (N);
Arg2 : Node_Id := Right_Opnd (N);
begin
Op := Entity (N);
while Scope (Op) /= Standard_Standard loop
Op := Homonym (Op);
pragma Assert (Present (Op));
end loop;
Set_Entity (N, Op);
if Typ /= Etype (Arg1) or else Typ = Etype (Arg2) then
Rewrite (Left_Opnd (N), Convert_To (Typ, Arg1));
Rewrite (Right_Opnd (N), Convert_To (Typ, Arg2));
Analyze (Left_Opnd (N));
Analyze (Right_Opnd (N));
end if;
Resolve_Arithmetic_Op (N, Typ);
end Resolve_Intrinsic_Operator;
------------------------
-- Resolve_Logical_Op --
------------------------
procedure Resolve_Logical_Op (N : Node_Id; Typ : Entity_Id) is
B_Typ : Entity_Id;
begin
-- Predefined operations on scalar types yield the base type. On
-- the other hand, logical operations on arrays yield the type of
-- the arguments (and the context).
if Is_Array_Type (Typ) then
B_Typ := Typ;
else
B_Typ := Base_Type (Typ);
end if;
-- The following test is required because the operands of the operation
-- may be literals, in which case the resulting type appears to be
-- compatible with a signed integer type, when in fact it is compatible
-- only with modular types. If the context itself is universal, the
-- operation is illegal.
if not Valid_Boolean_Arg (Typ) then
Error_Msg_N ("invalid context for logical operation", N);
Set_Etype (N, Any_Type);
return;
elsif Typ = Any_Modular then
Error_Msg_N
("no modular type available in this context", N);
Set_Etype (N, Any_Type);
return;
end if;
Resolve (Left_Opnd (N), B_Typ);
Resolve (Right_Opnd (N), B_Typ);
Check_Unset_Reference (Left_Opnd (N));
Check_Unset_Reference (Right_Opnd (N));
Set_Etype (N, B_Typ);
Generate_Operator_Reference (N);
Eval_Logical_Op (N);
end Resolve_Logical_Op;
---------------------------
-- Resolve_Membership_Op --
---------------------------
-- The context can only be a boolean type, and does not determine
-- the arguments. Arguments should be unambiguous, but the preference
-- rule for universal types applies.
procedure Resolve_Membership_Op (N : Node_Id; Typ : Entity_Id) is
L : constant Node_Id := Left_Opnd (N);
R : constant Node_Id := Right_Opnd (N);
T : Entity_Id;
begin
if L = Error or else R = Error then
return;
end if;
if not Is_Overloaded (R)
and then
(Etype (R) = Universal_Integer or else
Etype (R) = Universal_Real)
and then Is_Overloaded (L)
then
T := Etype (R);
else
T := Intersect_Types (L, R);
end if;
Resolve (L, T);
Check_Unset_Reference (L);
if Nkind (R) = N_Range
and then not Is_Scalar_Type (T)
then
Error_Msg_N ("scalar type required for range", R);
end if;
if Is_Entity_Name (R) then
Freeze_Expression (R);
else
Resolve (R, T);
Check_Unset_Reference (R);
end if;
Eval_Membership_Op (N);
end Resolve_Membership_Op;
------------------
-- Resolve_Null --
------------------
procedure Resolve_Null (N : Node_Id; Typ : Entity_Id) is
begin
-- For now allow circumvention of the restriction against
-- anonymous null access values via a debug switch to allow
-- for easier transition.
if not Debug_Flag_J
and then Ekind (Typ) = E_Anonymous_Access_Type
and then Comes_From_Source (N)
then
-- In the common case of a call which uses an explicitly null
-- value for an access parameter, give specialized error msg
if Nkind (Parent (N)) = N_Procedure_Call_Statement
or else
Nkind (Parent (N)) = N_Function_Call
then
Error_Msg_N
("null is not allowed as argument for an access parameter", N);
-- Standard message for all other cases (are there any?)
else
Error_Msg_N
("null cannot be of an anonymous access type", N);
end if;
end if;
-- In a distributed context, null for a remote access to subprogram
-- may need to be replaced with a special record aggregate. In this
-- case, return after having done the transformation.
if (Ekind (Typ) = E_Record_Type
or else Is_Remote_Access_To_Subprogram_Type (Typ))
and then Remote_AST_Null_Value (N, Typ)
then
return;
end if;
-- The null literal takes its type from the context.
Set_Etype (N, Typ);
end Resolve_Null;
-----------------------
-- Resolve_Op_Concat --
-----------------------
procedure Resolve_Op_Concat (N : Node_Id; Typ : Entity_Id) is
Btyp : constant Entity_Id := Base_Type (Typ);
Op1 : constant Node_Id := Left_Opnd (N);
Op2 : constant Node_Id := Right_Opnd (N);
procedure Resolve_Concatenation_Arg (Arg : Node_Id; Is_Comp : Boolean);
-- Internal procedure to resolve one operand of concatenation operator.
-- The operand is either of the array type or of the component type.
-- If the operand is an aggregate, and the component type is composite,
-- this is ambiguous if component type has aggregates.
-------------------------------
-- Resolve_Concatenation_Arg --
-------------------------------
procedure Resolve_Concatenation_Arg (Arg : Node_Id; Is_Comp : Boolean) is
begin
if In_Instance then
if Is_Comp
or else (not Is_Overloaded (Arg)
and then Etype (Arg) /= Any_Composite
and then Covers (Component_Type (Typ), Etype (Arg)))
then
Resolve (Arg, Component_Type (Typ));
else
Resolve (Arg, Btyp);
end if;
elsif Has_Compatible_Type (Arg, Component_Type (Typ)) then
if Nkind (Arg) = N_Aggregate
and then Is_Composite_Type (Component_Type (Typ))
then
if Is_Private_Type (Component_Type (Typ)) then
Resolve (Arg, Btyp);
else
Error_Msg_N ("ambiguous aggregate must be qualified", Arg);
Set_Etype (Arg, Any_Type);
end if;
else
if Is_Overloaded (Arg)
and then Has_Compatible_Type (Arg, Typ)
and then Etype (Arg) /= Any_Type
then
Error_Msg_N ("ambiguous operand for concatenation!", Arg);
declare
I : Interp_Index;
It : Interp;
begin
Get_First_Interp (Arg, I, It);
while Present (It.Nam) loop
if Base_Type (Etype (It.Nam)) = Base_Type (Typ)
or else Base_Type (Etype (It.Nam)) =
Base_Type (Component_Type (Typ))
then
Error_Msg_Sloc := Sloc (It.Nam);
Error_Msg_N ("\possible interpretation#", Arg);
end if;
Get_Next_Interp (I, It);
end loop;
end;
end if;
Resolve (Arg, Component_Type (Typ));
if Arg = Left_Opnd (N) then
Set_Is_Component_Left_Opnd (N);
else
Set_Is_Component_Right_Opnd (N);
end if;
end if;
else
Resolve (Arg, Btyp);
end if;
Check_Unset_Reference (Arg);
end Resolve_Concatenation_Arg;
-- Start of processing for Resolve_Op_Concat
begin
Set_Etype (N, Btyp);
if Is_Limited_Composite (Btyp) then
Error_Msg_N ("concatenation not available for limited array", N);
end if;
-- If the operands are themselves concatenations, resolve them as
-- such directly. This removes several layers of recursion and allows
-- GNAT to handle larger multiple concatenations.
if Nkind (Op1) = N_Op_Concat
and then not Is_Array_Type (Component_Type (Typ))
and then Entity (Op1) = Entity (N)
then
Resolve_Op_Concat (Op1, Typ);
else
Resolve_Concatenation_Arg
(Op1, Is_Component_Left_Opnd (N));
end if;
if Nkind (Op2) = N_Op_Concat
and then not Is_Array_Type (Component_Type (Typ))
and then Entity (Op2) = Entity (N)
then
Resolve_Op_Concat (Op2, Typ);
else
Resolve_Concatenation_Arg
(Op2, Is_Component_Right_Opnd (N));
end if;
Generate_Operator_Reference (N);
if Is_String_Type (Typ) then
Eval_Concatenation (N);
end if;
-- If this is not a static concatenation, but the result is a
-- string type (and not an array of strings) insure that static
-- string operands have their subtypes properly constructed.
if Nkind (N) /= N_String_Literal
and then Is_Character_Type (Component_Type (Typ))
then
Set_String_Literal_Subtype (Op1, Typ);
Set_String_Literal_Subtype (Op2, Typ);
end if;
end Resolve_Op_Concat;
----------------------
-- Resolve_Op_Expon --
----------------------
procedure Resolve_Op_Expon (N : Node_Id; Typ : Entity_Id) is
B_Typ : constant Entity_Id := Base_Type (Typ);
begin
-- Catch attempts to do fixed-point exponentation with universal
-- operands, which is a case where the illegality is not caught
-- during normal operator analysis.
if Is_Fixed_Point_Type (Typ) and then Comes_From_Source (N) then
Error_Msg_N ("exponentiation not available for fixed point", N);
return;
end if;
if Etype (Left_Opnd (N)) = Universal_Integer
or else Etype (Left_Opnd (N)) = Universal_Real
then
Check_For_Visible_Operator (N, B_Typ);
end if;
-- We do the resolution using the base type, because intermediate values
-- in expressions always are of the base type, not a subtype of it.
Resolve (Left_Opnd (N), B_Typ);
Resolve (Right_Opnd (N), Standard_Integer);
Check_Unset_Reference (Left_Opnd (N));
Check_Unset_Reference (Right_Opnd (N));
Set_Etype (N, B_Typ);
Generate_Operator_Reference (N);
Eval_Op_Expon (N);
-- Set overflow checking bit. Much cleverer code needed here eventually
-- and perhaps the Resolve routines should be separated for the various
-- arithmetic operations, since they will need different processing. ???
if Nkind (N) in N_Op then
if not Overflow_Checks_Suppressed (Etype (N)) then
Set_Do_Overflow_Check (N, True);
end if;
end if;
end Resolve_Op_Expon;
--------------------
-- Resolve_Op_Not --
--------------------
procedure Resolve_Op_Not (N : Node_Id; Typ : Entity_Id) is
B_Typ : Entity_Id;
function Parent_Is_Boolean return Boolean;
-- This function determines if the parent node is a boolean operator
-- or operation (comparison op, membership test, or short circuit form)
-- and the not in question is the left operand of this operation.
-- Note that if the not is in parens, then false is returned.
function Parent_Is_Boolean return Boolean is
begin
if Paren_Count (N) /= 0 then
return False;
else
case Nkind (Parent (N)) is
when N_Op_And |
N_Op_Eq |
N_Op_Ge |
N_Op_Gt |
N_Op_Le |
N_Op_Lt |
N_Op_Ne |
N_Op_Or |
N_Op_Xor |
N_In |
N_Not_In |
N_And_Then |
N_Or_Else =>
return Left_Opnd (Parent (N)) = N;
when others =>
return False;
end case;
end if;
end Parent_Is_Boolean;
-- Start of processing for Resolve_Op_Not
begin
-- Predefined operations on scalar types yield the base type. On
-- the other hand, logical operations on arrays yield the type of
-- the arguments (and the context).
if Is_Array_Type (Typ) then
B_Typ := Typ;
else
B_Typ := Base_Type (Typ);
end if;
if not Valid_Boolean_Arg (Typ) then
Error_Msg_N ("invalid operand type for operator&", N);
Set_Etype (N, Any_Type);
return;
elsif (Typ = Universal_Integer
or else Typ = Any_Modular)
then
if Parent_Is_Boolean then
Error_Msg_N
("operand of not must be enclosed in parentheses",
Right_Opnd (N));
else
Error_Msg_N
("no modular type available in this context", N);
end if;
Set_Etype (N, Any_Type);
return;
else
if not Is_Boolean_Type (Typ)
and then Parent_Is_Boolean
then
Error_Msg_N ("?not expression should be parenthesized here", N);
end if;
Resolve (Right_Opnd (N), B_Typ);
Check_Unset_Reference (Right_Opnd (N));
Set_Etype (N, B_Typ);
Generate_Operator_Reference (N);
Eval_Op_Not (N);
end if;
end Resolve_Op_Not;
-----------------------------
-- Resolve_Operator_Symbol --
-----------------------------
-- Nothing to be done, all resolved already
procedure Resolve_Operator_Symbol (N : Node_Id; Typ : Entity_Id) is
begin
null;
end Resolve_Operator_Symbol;
----------------------------------
-- Resolve_Qualified_Expression --
----------------------------------
procedure Resolve_Qualified_Expression (N : Node_Id; Typ : Entity_Id) is
Target_Typ : constant Entity_Id := Entity (Subtype_Mark (N));
Expr : constant Node_Id := Expression (N);
begin
Resolve (Expr, Target_Typ);
-- A qualified expression requires an exact match of the type,
-- class-wide matching is not allowed.
if Is_Class_Wide_Type (Target_Typ)
and then Base_Type (Etype (Expr)) /= Base_Type (Target_Typ)
then
Wrong_Type (Expr, Target_Typ);
end if;
-- If the target type is unconstrained, then we reset the type of
-- the result from the type of the expression. For other cases, the
-- actual subtype of the expression is the target type.
if Is_Composite_Type (Target_Typ)
and then not Is_Constrained (Target_Typ)
then
Set_Etype (N, Etype (Expr));
end if;
Eval_Qualified_Expression (N);
end Resolve_Qualified_Expression;
-------------------
-- Resolve_Range --
-------------------
procedure Resolve_Range (N : Node_Id; Typ : Entity_Id) is
L : constant Node_Id := Low_Bound (N);
H : constant Node_Id := High_Bound (N);
begin
Set_Etype (N, Typ);
Resolve (L, Typ);
Resolve (H, Typ);
Check_Unset_Reference (L);
Check_Unset_Reference (H);
-- We have to check the bounds for being within the base range as
-- required for a non-static context. Normally this is automatic
-- and done as part of evaluating expressions, but the N_Range
-- node is an exception, since in GNAT we consider this node to
-- be a subexpression, even though in Ada it is not. The circuit
-- in Sem_Eval could check for this, but that would put the test
-- on the main evaluation path for expressions.
Check_Non_Static_Context (L);
Check_Non_Static_Context (H);
end Resolve_Range;
--------------------------
-- Resolve_Real_Literal --
--------------------------
procedure Resolve_Real_Literal (N : Node_Id; Typ : Entity_Id) is
Actual_Typ : constant Entity_Id := Etype (N);
begin
-- Special processing for fixed-point literals to make sure that the
-- value is an exact multiple of small where this is required. We
-- skip this for the universal real case, and also for generic types.
if Is_Fixed_Point_Type (Typ)
and then Typ /= Universal_Fixed
and then Typ /= Any_Fixed
and then not Is_Generic_Type (Typ)
then
declare
Val : constant Ureal := Realval (N);
Cintr : constant Ureal := Val / Small_Value (Typ);
Cint : constant Uint := UR_Trunc (Cintr);
Den : constant Uint := Norm_Den (Cintr);
Stat : Boolean;
begin
-- Case of literal is not an exact multiple of the Small
if Den /= 1 then
-- For a source program literal for a decimal fixed-point
-- type, this is statically illegal (RM 4.9(36)).
if Is_Decimal_Fixed_Point_Type (Typ)
and then Actual_Typ = Universal_Real
and then Comes_From_Source (N)
then
Error_Msg_N ("value has extraneous low order digits", N);
end if;
-- Replace literal by a value that is the exact representation
-- of a value of the type, i.e. a multiple of the small value,
-- by truncation, since Machine_Rounds is false for all GNAT
-- fixed-point types (RM 4.9(38)).
Stat := Is_Static_Expression (N);
Rewrite (N,
Make_Real_Literal (Sloc (N),
Realval => Small_Value (Typ) * Cint));
Set_Is_Static_Expression (N, Stat);
end if;
-- In all cases, set the corresponding integer field
Set_Corresponding_Integer_Value (N, Cint);
end;
end if;
-- Now replace the actual type by the expected type as usual
Set_Etype (N, Typ);
Eval_Real_Literal (N);
end Resolve_Real_Literal;
-----------------------
-- Resolve_Reference --
-----------------------
procedure Resolve_Reference (N : Node_Id; Typ : Entity_Id) is
P : constant Node_Id := Prefix (N);
begin
-- Replace general access with specific type
if Ekind (Etype (N)) = E_Allocator_Type then
Set_Etype (N, Base_Type (Typ));
end if;
Resolve (P, Designated_Type (Etype (N)));
-- If we are taking the reference of a volatile entity, then treat
-- it as a potential modification of this entity. This is much too
-- conservative, but is necessary because remove side effects can
-- result in transformations of normal assignments into reference
-- sequences that otherwise fail to notice the modification.
if Is_Entity_Name (P) and then Is_Volatile (Entity (P)) then
Note_Possible_Modification (P);
end if;
end Resolve_Reference;
--------------------------------
-- Resolve_Selected_Component --
--------------------------------
procedure Resolve_Selected_Component (N : Node_Id; Typ : Entity_Id) is
Comp : Entity_Id;
Comp1 : Entity_Id := Empty; -- prevent junk warning
P : constant Node_Id := Prefix (N);
S : constant Node_Id := Selector_Name (N);
T : Entity_Id := Etype (P);
I : Interp_Index;
I1 : Interp_Index := 0; -- prevent junk warning
It : Interp;
It1 : Interp;
Found : Boolean;
function Init_Component return Boolean;
-- Check whether this is the initialization of a component within an
-- init_proc (by assignment or call to another init_proc). If true,
-- there is no need for a discriminant check.
--------------------
-- Init_Component --
--------------------
function Init_Component return Boolean is
begin
return Inside_Init_Proc
and then Nkind (Prefix (N)) = N_Identifier
and then Chars (Prefix (N)) = Name_uInit
and then Nkind (Parent (Parent (N))) = N_Case_Statement_Alternative;
end Init_Component;
-- Start of processing for Resolve_Selected_Component
begin
if Is_Overloaded (P) then
-- Use the context type to select the prefix that has a selector
-- of the correct name and type.
Found := False;
Get_First_Interp (P, I, It);
Search : while Present (It.Typ) loop
if Is_Access_Type (It.Typ) then
T := Designated_Type (It.Typ);
else
T := It.Typ;
end if;
if Is_Record_Type (T) then
Comp := First_Entity (T);
while Present (Comp) loop
if Chars (Comp) = Chars (S)
and then Covers (Etype (Comp), Typ)
then
if not Found then
Found := True;
I1 := I;
It1 := It;
Comp1 := Comp;
else
It := Disambiguate (P, I1, I, Any_Type);
if It = No_Interp then
Error_Msg_N
("ambiguous prefix for selected component", N);
Set_Etype (N, Typ);
return;
else
It1 := It;
if Scope (Comp1) /= It1.Typ then
-- Resolution chooses the new interpretation.
-- Find the component with the right name.
Comp1 := First_Entity (It1.Typ);
while Present (Comp1)
and then Chars (Comp1) /= Chars (S)
loop
Comp1 := Next_Entity (Comp1);
end loop;
end if;
exit Search;
end if;
end if;
end if;
Comp := Next_Entity (Comp);
end loop;
end if;
Get_Next_Interp (I, It);
end loop Search;
Resolve (P, It1.Typ);
Set_Etype (N, Typ);
Set_Entity (S, Comp1);
else
-- Resolve prefix with its type.
Resolve (P, T);
end if;
-- Deal with access type case
if Is_Access_Type (Etype (P)) then
Apply_Access_Check (N);
T := Designated_Type (Etype (P));
else
T := Etype (P);
end if;
if Has_Discriminants (T)
and then Present (Original_Record_Component (Entity (S)))
and then Ekind (Original_Record_Component (Entity (S))) = E_Component
and then Present (Discriminant_Checking_Func
(Original_Record_Component (Entity (S))))
and then not Discriminant_Checks_Suppressed (T)
and then not Init_Component
then
Set_Do_Discriminant_Check (N);
end if;
if Ekind (Entity (S)) = E_Void then
Error_Msg_N ("premature use of component", S);
end if;
-- If the prefix is a record conversion, this may be a renamed
-- discriminant whose bounds differ from those of the original
-- one, so we must ensure that a range check is performed.
if Nkind (P) = N_Type_Conversion
and then Ekind (Entity (S)) = E_Discriminant
then
Set_Etype (N, Base_Type (Typ));
end if;
-- Note: No Eval processing is required, because the prefix is of a
-- record type, or protected type, and neither can possibly be static.
end Resolve_Selected_Component;
-------------------
-- Resolve_Shift --
-------------------
procedure Resolve_Shift (N : Node_Id; Typ : Entity_Id) is
B_Typ : constant Entity_Id := Base_Type (Typ);
L : constant Node_Id := Left_Opnd (N);
R : constant Node_Id := Right_Opnd (N);
begin
-- We do the resolution using the base type, because intermediate values
-- in expressions always are of the base type, not a subtype of it.
Resolve (L, B_Typ);
Resolve (R, Standard_Natural);
Check_Unset_Reference (L);
Check_Unset_Reference (R);
Set_Etype (N, B_Typ);
Generate_Operator_Reference (N);
Eval_Shift (N);
end Resolve_Shift;
---------------------------
-- Resolve_Short_Circuit --
---------------------------
procedure Resolve_Short_Circuit (N : Node_Id; Typ : Entity_Id) is
B_Typ : constant Entity_Id := Base_Type (Typ);
L : constant Node_Id := Left_Opnd (N);
R : constant Node_Id := Right_Opnd (N);
begin
Resolve (L, B_Typ);
Resolve (R, B_Typ);
Check_Unset_Reference (L);
Check_Unset_Reference (R);
Set_Etype (N, B_Typ);
Eval_Short_Circuit (N);
end Resolve_Short_Circuit;
-------------------
-- Resolve_Slice --
-------------------
procedure Resolve_Slice (N : Node_Id; Typ : Entity_Id) is
Name : constant Node_Id := Prefix (N);
Drange : constant Node_Id := Discrete_Range (N);
Array_Type : Entity_Id := Empty;
Index : Node_Id;
begin
if Is_Overloaded (Name) then
-- Use the context type to select the prefix that yields the
-- correct array type.
declare
I : Interp_Index;
I1 : Interp_Index := 0;
It : Interp;
P : constant Node_Id := Prefix (N);
Found : Boolean := False;
begin
Get_First_Interp (P, I, It);
while Present (It.Typ) loop
if (Is_Array_Type (It.Typ)
and then Covers (Typ, It.Typ))
or else (Is_Access_Type (It.Typ)
and then Is_Array_Type (Designated_Type (It.Typ))
and then Covers (Typ, Designated_Type (It.Typ)))
then
if Found then
It := Disambiguate (P, I1, I, Any_Type);
if It = No_Interp then
Error_Msg_N ("ambiguous prefix for slicing", N);
Set_Etype (N, Typ);
return;
else
Found := True;
Array_Type := It.Typ;
I1 := I;
end if;
else
Found := True;
Array_Type := It.Typ;
I1 := I;
end if;
end if;
Get_Next_Interp (I, It);
end loop;
end;
else
Array_Type := Etype (Name);
end if;
Resolve (Name, Array_Type);
if Is_Access_Type (Array_Type) then
Apply_Access_Check (N);
Array_Type := Designated_Type (Array_Type);
elsif Is_Entity_Name (Name)
or else (Nkind (Name) = N_Function_Call
and then not Is_Constrained (Etype (Name)))
then
Array_Type := Get_Actual_Subtype (Name);
end if;
-- If name was overloaded, set slice type correctly now
Set_Etype (N, Array_Type);
-- If the range is specified by a subtype mark, no resolution
-- is necessary.
if not Is_Entity_Name (Drange) then
Index := First_Index (Array_Type);
Resolve (Drange, Base_Type (Etype (Index)));
if Nkind (Drange) = N_Range then
Apply_Range_Check (Drange, Etype (Index));
end if;
end if;
Set_Slice_Subtype (N);
Eval_Slice (N);
end Resolve_Slice;
----------------------------
-- Resolve_String_Literal --
----------------------------
procedure Resolve_String_Literal (N : Node_Id; Typ : Entity_Id) is
C_Typ : constant Entity_Id := Component_Type (Typ);
R_Typ : constant Entity_Id := Root_Type (C_Typ);
Loc : constant Source_Ptr := Sloc (N);
Str : constant String_Id := Strval (N);
Strlen : constant Nat := String_Length (Str);
Subtype_Id : Entity_Id;
Need_Check : Boolean;
begin
-- For a string appearing in a concatenation, defer creation of the
-- string_literal_subtype until the end of the resolution of the
-- concatenation, because the literal may be constant-folded away.
-- This is a useful optimization for long concatenation expressions.
-- If the string is an aggregate built for a single character (which
-- happens in a non-static context) or a is null string to which special
-- checks may apply, we build the subtype. Wide strings must also get
-- a string subtype if they come from a one character aggregate. Strings
-- generated by attributes might be static, but it is often hard to
-- determine whether the enclosing context is static, so we generate
-- subtypes for them as well, thus losing some rarer optimizations ???
-- Same for strings that come from a static conversion.
Need_Check :=
(Strlen = 0 and then Typ /= Standard_String)
or else Nkind (Parent (N)) /= N_Op_Concat
or else (N /= Left_Opnd (Parent (N))
and then N /= Right_Opnd (Parent (N)))
or else (Typ = Standard_Wide_String
and then Nkind (Original_Node (N)) /= N_String_Literal);
-- If the resolving type is itself a string literal subtype, we
-- can just reuse it, since there is no point in creating another.
if Ekind (Typ) = E_String_Literal_Subtype then
Subtype_Id := Typ;
elsif Nkind (Parent (N)) = N_Op_Concat
and then not Need_Check
and then Nkind (Original_Node (N)) /= N_Character_Literal
and then Nkind (Original_Node (N)) /= N_Attribute_Reference
and then Nkind (Original_Node (N)) /= N_Qualified_Expression
and then Nkind (Original_Node (N)) /= N_Type_Conversion
then
Subtype_Id := Typ;
-- Otherwise we must create a string literal subtype. Note that the
-- whole idea of string literal subtypes is simply to avoid the need
-- for building a full fledged array subtype for each literal.
else
Set_String_Literal_Subtype (N, Typ);
Subtype_Id := Etype (N);
end if;
if Nkind (Parent (N)) /= N_Op_Concat
or else Need_Check
then
Set_Etype (N, Subtype_Id);
Eval_String_Literal (N);
end if;
if Is_Limited_Composite (Typ)
or else Is_Private_Composite (Typ)
then
Error_Msg_N ("string literal not available for private array", N);
Set_Etype (N, Any_Type);
return;
end if;
-- The validity of a null string has been checked in the
-- call to Eval_String_Literal.
if Strlen = 0 then
return;
-- Always accept string literal with component type Any_Character,
-- which occurs in error situations and in comparisons of literals,
-- both of which should accept all literals.
elsif R_Typ = Any_Character then
return;
-- If the type is bit-packed, then we always tranform the string
-- literal into a full fledged aggregate.
elsif Is_Bit_Packed_Array (Typ) then
null;
-- Deal with cases of Wide_String and String
else
-- For Standard.Wide_String, or any other type whose component
-- type is Standard.Wide_Character, we know that all the
-- characters in the string must be acceptable, since the parser
-- accepted the characters as valid character literals.
if R_Typ = Standard_Wide_Character then
null;
-- For the case of Standard.String, or any other type whose
-- component type is Standard.Character, we must make sure that
-- there are no wide characters in the string, i.e. that it is
-- entirely composed of characters in range of type String.
-- If the string literal is the result of a static concatenation,
-- the test has already been performed on the components, and need
-- not be repeated.
elsif R_Typ = Standard_Character
and then Nkind (Original_Node (N)) /= N_Op_Concat
then
for J in 1 .. Strlen loop
if not In_Character_Range (Get_String_Char (Str, J)) then
-- If we are out of range, post error. This is one of the
-- very few places that we place the flag in the middle of
-- a token, right under the offending wide character.
Error_Msg
("literal out of range of type Character",
Source_Ptr (Int (Loc) + J));
return;
end if;
end loop;
-- If the root type is not a standard character, then we will convert
-- the string into an aggregate and will let the aggregate code do
-- the checking.
else
null;
end if;
-- See if the component type of the array corresponding to the
-- string has compile time known bounds. If yes we can directly
-- check whether the evaluation of the string will raise constraint
-- error. Otherwise we need to transform the string literal into
-- the corresponding character aggregate and let the aggregate
-- code do the checking.
if R_Typ = Standard_Wide_Character
or else R_Typ = Standard_Character
then
-- Check for the case of full range, where we are definitely OK
if Component_Type (Typ) = Base_Type (Component_Type (Typ)) then
return;
end if;
-- Here the range is not the complete base type range, so check
declare
Comp_Typ_Lo : constant Node_Id :=
Type_Low_Bound (Component_Type (Typ));
Comp_Typ_Hi : constant Node_Id :=
Type_High_Bound (Component_Type (Typ));
Char_Val : Uint;
begin
if Compile_Time_Known_Value (Comp_Typ_Lo)
and then Compile_Time_Known_Value (Comp_Typ_Hi)
then
for J in 1 .. Strlen loop
Char_Val := UI_From_Int (Int (Get_String_Char (Str, J)));
if Char_Val < Expr_Value (Comp_Typ_Lo)
or else Char_Val > Expr_Value (Comp_Typ_Hi)
then
Apply_Compile_Time_Constraint_Error
(N, "character out of range?",
Loc => Source_Ptr (Int (Loc) + J));
end if;
end loop;
return;
end if;
end;
end if;
end if;
-- If we got here we meed to transform the string literal into the
-- equivalent qualified positional array aggregate. This is rather
-- heavy artillery for this situation, but it is hard work to avoid.
declare
Lits : List_Id := New_List;
P : Source_Ptr := Loc + 1;
C : Char_Code;
begin
-- Build the character literals, we give them source locations
-- that correspond to the string positions, which is a bit tricky
-- given the possible presence of wide character escape sequences.
for J in 1 .. Strlen loop
C := Get_String_Char (Str, J);
Set_Character_Literal_Name (C);
Append_To (Lits,
Make_Character_Literal (P, Name_Find, C));
if In_Character_Range (C) then
P := P + 1;
-- Should we have a call to Skip_Wide here ???
-- ??? else
-- Skip_Wide (P);
end if;
end loop;
Rewrite (N,
Make_Qualified_Expression (Loc,
Subtype_Mark => New_Reference_To (Typ, Loc),
Expression =>
Make_Aggregate (Loc, Expressions => Lits)));
Analyze_And_Resolve (N, Typ);
end;
end Resolve_String_Literal;
-----------------------------
-- Resolve_Subprogram_Info --
-----------------------------
procedure Resolve_Subprogram_Info (N : Node_Id; Typ : Entity_Id) is
begin
Set_Etype (N, Typ);
end Resolve_Subprogram_Info;
-----------------------------
-- Resolve_Type_Conversion --
-----------------------------
procedure Resolve_Type_Conversion (N : Node_Id; Typ : Entity_Id) is
Target_Type : constant Entity_Id := Etype (N);
Conv_OK : constant Boolean := Conversion_OK (N);
Operand : Node_Id;
Opnd_Type : Entity_Id;
Rop : Node_Id;
begin
Operand := Expression (N);
if not Conv_OK
and then not Valid_Conversion (N, Target_Type, Operand)
then
return;
end if;
if Etype (Operand) = Any_Fixed then
-- Mixed-mode operation involving a literal. Context must be a fixed
-- type which is applied to the literal subsequently.
if Is_Fixed_Point_Type (Typ) then
Set_Etype (Operand, Universal_Real);
elsif Is_Numeric_Type (Typ)
and then (Nkind (Operand) = N_Op_Multiply
or else Nkind (Operand) = N_Op_Divide)
and then (Etype (Right_Opnd (Operand)) = Universal_Real
or else Etype (Left_Opnd (Operand)) = Universal_Real)
then
if Unique_Fixed_Point_Type (N) = Any_Type then
return; -- expression is ambiguous.
else
Set_Etype (Operand, Standard_Duration);
end if;
if Etype (Right_Opnd (Operand)) = Universal_Real then
Rop := New_Copy_Tree (Right_Opnd (Operand));
else
Rop := New_Copy_Tree (Left_Opnd (Operand));
end if;
Resolve (Rop, Standard_Long_Long_Float);
if Realval (Rop) /= Ureal_0
and then abs (Realval (Rop)) < Delta_Value (Standard_Duration)
then
Error_Msg_N ("universal real operand can only be interpreted?",
Rop);
Error_Msg_N ("\as Duration, and will lose precision?", Rop);
end if;
else
Error_Msg_N ("invalid context for mixed mode operation", N);
Set_Etype (Operand, Any_Type);
return;
end if;
end if;
Opnd_Type := Etype (Operand);
Resolve (Operand, Opnd_Type);
-- Note: we do the Eval_Type_Conversion call before applying the
-- required checks for a subtype conversion. This is important,
-- since both are prepared under certain circumstances to change
-- the type conversion to a constraint error node, but in the case
-- of Eval_Type_Conversion this may reflect an illegality in the
-- static case, and we would miss the illegality (getting only a
-- warning message), if we applied the type conversion checks first.
Eval_Type_Conversion (N);
-- If after evaluation, we still have a type conversion, then we
-- may need to apply checks required for a subtype conversion.
-- Skip these type conversion checks if universal fixed operands
-- operands involved, since range checks are handled separately for
-- these cases (in the appropriate Expand routines in unit Exp_Fixd).
if Nkind (N) = N_Type_Conversion
and then not Is_Generic_Type (Root_Type (Target_Type))
and then Target_Type /= Universal_Fixed
and then Opnd_Type /= Universal_Fixed
then
Apply_Type_Conversion_Checks (N);
end if;
-- Issue warning for conversion of simple object to its own type
if Warn_On_Redundant_Constructs
and then Comes_From_Source (N)
and then Nkind (N) = N_Type_Conversion
and then Is_Entity_Name (Expression (N))
and then Etype (Entity (Expression (N))) = Target_Type
then
Error_Msg_NE
("?useless conversion, & has this type",
N, Entity (Expression (N)));
end if;
end Resolve_Type_Conversion;
----------------------
-- Resolve_Unary_Op --
----------------------
procedure Resolve_Unary_Op (N : Node_Id; Typ : Entity_Id) is
B_Typ : Entity_Id := Base_Type (Typ);
R : constant Node_Id := Right_Opnd (N);
begin
-- Generate warning for expressions like -5 mod 3
if Paren_Count (N) = 0
and then Nkind (N) = N_Op_Minus
and then Nkind (Right_Opnd (N)) = N_Op_Mod
then
Error_Msg_N
("?unary minus expression should be parenthesized here", N);
end if;
if Etype (R) = Universal_Integer
or else Etype (R) = Universal_Real
then
Check_For_Visible_Operator (N, B_Typ);
end if;
Set_Etype (N, B_Typ);
Resolve (R, B_Typ);
Check_Unset_Reference (R);
Generate_Operator_Reference (N);
Eval_Unary_Op (N);
-- Set overflow checking bit. Much cleverer code needed here eventually
-- and perhaps the Resolve routines should be separated for the various
-- arithmetic operations, since they will need different processing ???
if Nkind (N) in N_Op then
if not Overflow_Checks_Suppressed (Etype (N)) then
Set_Do_Overflow_Check (N, True);
end if;
end if;
end Resolve_Unary_Op;
----------------------------------
-- Resolve_Unchecked_Expression --
----------------------------------
procedure Resolve_Unchecked_Expression
(N : Node_Id;
Typ : Entity_Id)
is
begin
Resolve (Expression (N), Typ, Suppress => All_Checks);
Set_Etype (N, Typ);
end Resolve_Unchecked_Expression;
---------------------------------------
-- Resolve_Unchecked_Type_Conversion --
---------------------------------------
procedure Resolve_Unchecked_Type_Conversion
(N : Node_Id;
Typ : Entity_Id)
is
Operand : constant Node_Id := Expression (N);
Opnd_Type : constant Entity_Id := Etype (Operand);
begin
-- Resolve operand using its own type.
Resolve (Operand, Opnd_Type);
Eval_Unchecked_Conversion (N);
end Resolve_Unchecked_Type_Conversion;
------------------------------
-- Rewrite_Operator_As_Call --
------------------------------
procedure Rewrite_Operator_As_Call (N : Node_Id; Nam : Entity_Id) is
Loc : Source_Ptr := Sloc (N);
Actuals : List_Id := New_List;
New_N : Node_Id;
begin
if Nkind (N) in N_Binary_Op then
Append (Left_Opnd (N), Actuals);
end if;
Append (Right_Opnd (N), Actuals);
New_N :=
Make_Function_Call (Sloc => Loc,
Name => New_Occurrence_Of (Nam, Loc),
Parameter_Associations => Actuals);
Preserve_Comes_From_Source (New_N, N);
Preserve_Comes_From_Source (Name (New_N), N);
Rewrite (N, New_N);
Set_Etype (N, Etype (Nam));
end Rewrite_Operator_As_Call;
------------------------------
-- Rewrite_Renamed_Operator --
------------------------------
procedure Rewrite_Renamed_Operator (N : Node_Id; Op : Entity_Id) is
Nam : constant Name_Id := Chars (Op);
Is_Binary : constant Boolean := Nkind (N) in N_Binary_Op;
Op_Node : Node_Id;
begin
if Chars (N) /= Nam then
-- Rewrite the operator node using the real operator, not its
-- renaming.
Op_Node := New_Node (Operator_Kind (Nam, Is_Binary), Sloc (N));
Set_Chars (Op_Node, Nam);
Set_Etype (Op_Node, Etype (N));
Set_Entity (Op_Node, Op);
Set_Right_Opnd (Op_Node, Right_Opnd (N));
Generate_Reference (Op, N);
if Is_Binary then
Set_Left_Opnd (Op_Node, Left_Opnd (N));
end if;
Rewrite (N, Op_Node);
end if;
end Rewrite_Renamed_Operator;
-----------------------
-- Set_Slice_Subtype --
-----------------------
-- Build an implicit subtype declaration to represent the type delivered
-- by the slice. This is an abbreviated version of an array subtype. We
-- define an index subtype for the slice, using either the subtype name
-- or the discrete range of the slice. To be consistent with index usage
-- elsewhere, we create a list header to hold the single index. This list
-- is not otherwise attached to the syntax tree.
procedure Set_Slice_Subtype (N : Node_Id) is
Loc : constant Source_Ptr := Sloc (N);
Index : Node_Id;
Index_List : List_Id := New_List;
Index_Subtype : Entity_Id;
Index_Type : Entity_Id;
Slice_Subtype : Entity_Id;
Drange : constant Node_Id := Discrete_Range (N);
begin
if Is_Entity_Name (Drange) then
Index_Subtype := Entity (Drange);
else
-- We force the evaluation of a range. This is definitely needed in
-- the renamed case, and seems safer to do unconditionally. Note in
-- any case that since we will create and insert an Itype referring
-- to this range, we must make sure any side effect removal actions
-- are inserted before the Itype definition.
if Nkind (Drange) = N_Range then
Force_Evaluation (Low_Bound (Drange));
Force_Evaluation (High_Bound (Drange));
end if;
Index_Type := Base_Type (Etype (Drange));
Index_Subtype := Create_Itype (Subtype_Kind (Ekind (Index_Type)), N);
Set_Scalar_Range (Index_Subtype, Drange);
Set_Etype (Index_Subtype, Index_Type);
Set_Size_Info (Index_Subtype, Index_Type);
Set_RM_Size (Index_Subtype, RM_Size (Index_Type));
end if;
Slice_Subtype := Create_Itype (E_Array_Subtype, N);
Index := New_Occurrence_Of (Index_Subtype, Loc);
Set_Etype (Index, Index_Subtype);
Append (Index, Index_List);
Set_Component_Type (Slice_Subtype, Component_Type (Etype (N)));
Set_First_Index (Slice_Subtype, Index);
Set_Etype (Slice_Subtype, Base_Type (Etype (N)));
Set_Is_Constrained (Slice_Subtype, True);
Init_Size_Align (Slice_Subtype);
Check_Compile_Time_Size (Slice_Subtype);
-- The Etype of the existing Slice node is reset to this slice
-- subtype. Its bounds are obtained from its first index.
Set_Etype (N, Slice_Subtype);
-- In the packed case, this must be immediately frozen
-- Couldn't we always freeze here??? and if we did, then the above
-- call to Check_Compile_Time_Size could be eliminated, which would
-- be nice, because then that routine could be made private to Freeze.
if Is_Packed (Slice_Subtype) and not In_Default_Expression then
Freeze_Itype (Slice_Subtype, N);
end if;
end Set_Slice_Subtype;
--------------------------------
-- Set_String_Literal_Subtype --
--------------------------------
procedure Set_String_Literal_Subtype (N : Node_Id; Typ : Entity_Id) is
Subtype_Id : Entity_Id;
begin
if Nkind (N) /= N_String_Literal then
return;
else
Subtype_Id := Create_Itype (E_String_Literal_Subtype, N);
end if;
Set_Component_Type (Subtype_Id, Component_Type (Typ));
Set_String_Literal_Length (Subtype_Id,
UI_From_Int (String_Length (Strval (N))));
Set_Etype (Subtype_Id, Base_Type (Typ));
Set_Is_Constrained (Subtype_Id);
-- The low bound is set from the low bound of the corresponding
-- index type. Note that we do not store the high bound in the
-- string literal subtype, but it can be deduced if necssary
-- from the length and the low bound.
Set_String_Literal_Low_Bound
(Subtype_Id, Type_Low_Bound (Etype (First_Index (Typ))));
Set_Etype (N, Subtype_Id);
end Set_String_Literal_Subtype;
-----------------------------
-- Unique_Fixed_Point_Type --
-----------------------------
function Unique_Fixed_Point_Type (N : Node_Id) return Entity_Id is
T1 : Entity_Id := Empty;
T2 : Entity_Id;
Item : Node_Id;
Scop : Entity_Id;
procedure Fixed_Point_Error;
-- If true ambiguity, give details.
procedure Fixed_Point_Error is
begin
Error_Msg_N ("ambiguous universal_fixed_expression", N);
Error_Msg_NE ("\possible interpretation as}", N, T1);
Error_Msg_NE ("\possible interpretation as}", N, T2);
end Fixed_Point_Error;
begin
-- The operations on Duration are visible, so Duration is always a
-- possible interpretation.
T1 := Standard_Duration;
Scop := Current_Scope;
-- Look for fixed-point types in enclosing scopes.
while Scop /= Standard_Standard loop
T2 := First_Entity (Scop);
while Present (T2) loop
if Is_Fixed_Point_Type (T2)
and then Current_Entity (T2) = T2
and then Scope (Base_Type (T2)) = Scop
then
if Present (T1) then
Fixed_Point_Error;
return Any_Type;
else
T1 := T2;
end if;
end if;
Next_Entity (T2);
end loop;
Scop := Scope (Scop);
end loop;
-- Look for visible fixed type declarations in the context.
Item := First (Context_Items (Cunit (Current_Sem_Unit)));
while Present (Item) loop
if Nkind (Item) = N_With_Clause then
Scop := Entity (Name (Item));
T2 := First_Entity (Scop);
while Present (T2) loop
if Is_Fixed_Point_Type (T2)
and then Scope (Base_Type (T2)) = Scop
and then (Is_Potentially_Use_Visible (T2)
or else In_Use (T2))
then
if Present (T1) then
Fixed_Point_Error;
return Any_Type;
else
T1 := T2;
end if;
end if;
Next_Entity (T2);
end loop;
end if;
Next (Item);
end loop;
if Nkind (N) = N_Real_Literal then
Error_Msg_NE ("real literal interpreted as }?", N, T1);
else
Error_Msg_NE ("universal_fixed expression interpreted as }?", N, T1);
end if;
return T1;
end Unique_Fixed_Point_Type;
----------------------
-- Valid_Conversion --
----------------------
function Valid_Conversion
(N : Node_Id;
Target : Entity_Id;
Operand : Node_Id)
return Boolean
is
Target_Type : Entity_Id := Base_Type (Target);
Opnd_Type : Entity_Id := Etype (Operand);
function Conversion_Check
(Valid : Boolean;
Msg : String)
return Boolean;
-- Little routine to post Msg if Valid is False, returns Valid value
function Valid_Tagged_Conversion
(Target_Type : Entity_Id;
Opnd_Type : Entity_Id)
return Boolean;
-- Specifically test for validity of tagged conversions
----------------------
-- Conversion_Check --
----------------------
function Conversion_Check
(Valid : Boolean;
Msg : String)
return Boolean
is
begin
if not Valid then
Error_Msg_N (Msg, Operand);
end if;
return Valid;
end Conversion_Check;
-----------------------------
-- Valid_Tagged_Conversion --
-----------------------------
function Valid_Tagged_Conversion
(Target_Type : Entity_Id;
Opnd_Type : Entity_Id)
return Boolean
is
begin
-- Upward conversions are allowed (RM 4.6(22)).
if Covers (Target_Type, Opnd_Type)
or else Is_Ancestor (Target_Type, Opnd_Type)
then
return True;
-- Downward conversion are allowed if the operand is
-- is class-wide (RM 4.6(23)).
elsif Is_Class_Wide_Type (Opnd_Type)
and then Covers (Opnd_Type, Target_Type)
then
return True;
elsif Covers (Opnd_Type, Target_Type)
or else Is_Ancestor (Opnd_Type, Target_Type)
then
return
Conversion_Check (False,
"downward conversion of tagged objects not allowed");
else
Error_Msg_NE
("invalid tagged conversion, not compatible with}",
N, First_Subtype (Opnd_Type));
return False;
end if;
end Valid_Tagged_Conversion;
-- Start of processing for Valid_Conversion
begin
Check_Parameterless_Call (Operand);
if Is_Overloaded (Operand) then
declare
I : Interp_Index;
I1 : Interp_Index;
It : Interp;
It1 : Interp;
N1 : Entity_Id;
begin
-- Remove procedure calls, which syntactically cannot appear
-- in this context, but which cannot be removed by type checking,
-- because the context does not impose a type.
Get_First_Interp (Operand, I, It);
while Present (It.Typ) loop
if It.Typ = Standard_Void_Type then
Remove_Interp (I);
end if;
Get_Next_Interp (I, It);
end loop;
Get_First_Interp (Operand, I, It);
I1 := I;
It1 := It;
if No (It.Typ) then
Error_Msg_N ("illegal operand in conversion", Operand);
return False;
end if;
Get_Next_Interp (I, It);
if Present (It.Typ) then
N1 := It1.Nam;
It1 := Disambiguate (Operand, I1, I, Any_Type);
if It1 = No_Interp then
Error_Msg_N ("ambiguous operand in conversion", Operand);
Error_Msg_Sloc := Sloc (It.Nam);
Error_Msg_N ("possible interpretation#!", Operand);
Error_Msg_Sloc := Sloc (N1);
Error_Msg_N ("possible interpretation#!", Operand);
return False;
end if;
end if;
Set_Etype (Operand, It1.Typ);
Opnd_Type := It1.Typ;
end;
end if;
if Chars (Current_Scope) = Name_Unchecked_Conversion then
-- This check is dubious, what if there were a user defined
-- scope whose name was Unchecked_Conversion ???
return True;
elsif Is_Numeric_Type (Target_Type) then
if Opnd_Type = Universal_Fixed then
return True;
else
return Conversion_Check (Is_Numeric_Type (Opnd_Type),
"illegal operand for numeric conversion");
end if;
elsif Is_Array_Type (Target_Type) then
if not Is_Array_Type (Opnd_Type)
or else Opnd_Type = Any_Composite
or else Opnd_Type = Any_String
then
Error_Msg_N
("illegal operand for array conversion", Operand);
return False;
elsif Number_Dimensions (Target_Type) /=
Number_Dimensions (Opnd_Type)
then
Error_Msg_N
("incompatible number of dimensions for conversion", Operand);
return False;
else
declare
Target_Index : Node_Id := First_Index (Target_Type);
Opnd_Index : Node_Id := First_Index (Opnd_Type);
Target_Index_Type : Entity_Id;
Opnd_Index_Type : Entity_Id;
Target_Comp_Type : Entity_Id := Component_Type (Target_Type);
Opnd_Comp_Type : Entity_Id := Component_Type (Opnd_Type);
begin
while Present (Target_Index) and then Present (Opnd_Index) loop
Target_Index_Type := Etype (Target_Index);
Opnd_Index_Type := Etype (Opnd_Index);
if not (Is_Integer_Type (Target_Index_Type)
and then Is_Integer_Type (Opnd_Index_Type))
and then (Root_Type (Target_Index_Type)
/= Root_Type (Opnd_Index_Type))
then
Error_Msg_N
("incompatible index types for array conversion",
Operand);
return False;
end if;
Next_Index (Target_Index);
Next_Index (Opnd_Index);
end loop;
if Base_Type (Target_Comp_Type) /=
Base_Type (Opnd_Comp_Type)
then
Error_Msg_N
("incompatible component types for array conversion",
Operand);
return False;
elsif
Is_Constrained (Target_Comp_Type)
/= Is_Constrained (Opnd_Comp_Type)
or else not Subtypes_Statically_Match
(Target_Comp_Type, Opnd_Comp_Type)
then
Error_Msg_N
("component subtypes must statically match", Operand);
return False;
end if;
end;
end if;
return True;
elsif (Ekind (Target_Type) = E_General_Access_Type
or else Ekind (Target_Type) = E_Anonymous_Access_Type)
and then
Conversion_Check
(Is_Access_Type (Opnd_Type)
and then Ekind (Opnd_Type) /=
E_Access_Subprogram_Type
and then Ekind (Opnd_Type) /=
E_Access_Protected_Subprogram_Type,
"must be an access-to-object type")
then
if Is_Access_Constant (Opnd_Type)
and then not Is_Access_Constant (Target_Type)
then
Error_Msg_N
("access-to-constant operand type not allowed", Operand);
return False;
end if;
-- Check the static accessibility rule of 4.6(17). Note that
-- the check is not enforced when within an instance body, since
-- the RM requires such cases to be caught at run time.
if Ekind (Target_Type) /= E_Anonymous_Access_Type then
if Type_Access_Level (Opnd_Type)
> Type_Access_Level (Target_Type)
then
-- In an instance, this is a run-time check, but one we
-- know will fail, so generate an appropriate warning.
-- The raise will be generated by Expand_N_Type_Conversion.
if In_Instance_Body then
Error_Msg_N
("?cannot convert local pointer to non-local access type",
Operand);
Error_Msg_N
("?Program_Error will be raised at run time", Operand);
else
Error_Msg_N
("cannot convert local pointer to non-local access type",
Operand);
return False;
end if;
elsif Ekind (Opnd_Type) = E_Anonymous_Access_Type then
-- When the operand is a selected access discriminant
-- the check needs to be made against the level of the
-- object denoted by the prefix of the selected name.
-- (Object_Access_Level handles checking the prefix
-- of the operand for this case.)
if Nkind (Operand) = N_Selected_Component
and then Object_Access_Level (Operand)
> Type_Access_Level (Target_Type)
then
-- In an instance, this is a run-time check, but one we
-- know will fail, so generate an appropriate warning.
-- The raise will be generated by Expand_N_Type_Conversion.
if In_Instance_Body then
Error_Msg_N
("?cannot convert access discriminant to non-local" &
" access type", Operand);
Error_Msg_N
("?Program_Error will be raised at run time", Operand);
else
Error_Msg_N
("cannot convert access discriminant to non-local" &
" access type", Operand);
return False;
end if;
end if;
-- The case of a reference to an access discriminant
-- from within a type declaration (which will appear
-- as a discriminal) is always illegal because the
-- level of the discriminant is considered to be
-- deeper than any (namable) access type.
if Is_Entity_Name (Operand)
and then (Ekind (Entity (Operand)) = E_In_Parameter
or else Ekind (Entity (Operand)) = E_Constant)
and then Present (Discriminal_Link (Entity (Operand)))
then
Error_Msg_N
("discriminant has deeper accessibility level than target",
Operand);
return False;
end if;
end if;
end if;
declare
Target : constant Entity_Id := Designated_Type (Target_Type);
Opnd : constant Entity_Id := Designated_Type (Opnd_Type);
begin
if Is_Tagged_Type (Target) then
return Valid_Tagged_Conversion (Target, Opnd);
else
if Base_Type (Target) /= Base_Type (Opnd) then
Error_Msg_NE
("target designated type not compatible with }",
N, Base_Type (Opnd));
return False;
elsif not Subtypes_Statically_Match (Target, Opnd)
and then (not Has_Discriminants (Target)
or else Is_Constrained (Target))
then
Error_Msg_NE
("target designated subtype not compatible with }",
N, Opnd);
return False;
else
return True;
end if;
end if;
end;
elsif Ekind (Target_Type) = E_Access_Subprogram_Type
and then Conversion_Check
(Ekind (Base_Type (Opnd_Type)) = E_Access_Subprogram_Type,
"illegal operand for access subprogram conversion")
then
-- Check that the designated types are subtype conformant
if not Subtype_Conformant (Designated_Type (Opnd_Type),
Designated_Type (Target_Type))
then
Error_Msg_N
("operand type is not subtype conformant with target type",
Operand);
end if;
-- Check the static accessibility rule of 4.6(20)
if Type_Access_Level (Opnd_Type) >
Type_Access_Level (Target_Type)
then
Error_Msg_N
("operand type has deeper accessibility level than target",
Operand);
-- Check that if the operand type is declared in a generic body,
-- then the target type must be declared within that same body
-- (enforces last sentence of 4.6(20)).
elsif Present (Enclosing_Generic_Body (Opnd_Type)) then
declare
O_Gen : constant Node_Id :=
Enclosing_Generic_Body (Opnd_Type);
T_Gen : Node_Id :=
Enclosing_Generic_Body (Target_Type);
begin
while Present (T_Gen) and then T_Gen /= O_Gen loop
T_Gen := Enclosing_Generic_Body (T_Gen);
end loop;
if T_Gen /= O_Gen then
Error_Msg_N
("target type must be declared in same generic body"
& " as operand type", N);
end if;
end;
end if;
return True;
elsif Is_Remote_Access_To_Subprogram_Type (Target_Type)
and then Is_Remote_Access_To_Subprogram_Type (Opnd_Type)
then
-- It is valid to convert from one RAS type to another provided
-- that their specification statically match.
Check_Subtype_Conformant
(New_Id =>
Designated_Type (Corresponding_Remote_Type (Target_Type)),
Old_Id =>
Designated_Type (Corresponding_Remote_Type (Opnd_Type)),
Err_Loc =>
N);
return True;
elsif Is_Tagged_Type (Target_Type) then
return Valid_Tagged_Conversion (Target_Type, Opnd_Type);
-- Types derived from the same root type are convertible.
elsif Root_Type (Target_Type) = Root_Type (Opnd_Type) then
return True;
-- In an instance, there may be inconsistent views of the same
-- type, or types derived from the same type.
elsif In_Instance
and then Underlying_Type (Target_Type) = Underlying_Type (Opnd_Type)
then
return True;
-- Special check for common access type error case
elsif Ekind (Target_Type) = E_Access_Type
and then Is_Access_Type (Opnd_Type)
then
Error_Msg_N ("target type must be general access type!", N);
Error_Msg_NE ("add ALL to }!", N, Target_Type);
return False;
else
Error_Msg_NE ("invalid conversion, not compatible with }",
N, Opnd_Type);
return False;
end if;
end Valid_Conversion;
end Sem_Res;