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1474 | --
-- Copyright (C) 2014-2022, AdaCore
-- SPDX-License-Identifier: Apache-2.0
--
with Ada.Exceptions;
with Ada.Strings.Wide_Wide_Unbounded; use Ada.Strings.Wide_Wide_Unbounded;
with GNATCOLL.GMP.Integers.Misc;
with Libadalang.Analysis; use Libadalang.Analysis;
with Libadalang.Common; use Libadalang.Common;
with Libadalang.Sources; use Libadalang.Sources;
package body Libadalang.Expr_Eval is
use type GNATCOLL.GMP.Integers.Big_Integer;
use type GNATCOLL.GMP.Rational_Numbers.Rational;
function "+" (S : Wide_Wide_String) return Unbounded_Wide_Wide_String
renames To_Unbounded_Wide_Wide_String;
function Create_Enum_Result
(Expr_Type : LAL.Base_Type_Decl;
Value : LAL.Enum_Literal_Decl) return Eval_Result;
-- Helper to create Eval_Result values to wrap enumeration literals
function Create_Int_Result
(Expr_Type : LAL.Base_Type_Decl;
Value : Big_Integer) return Eval_Result;
function Create_Int_Result
(Expr_Type : LAL.Base_Type_Decl;
Value : Integer) return Eval_Result;
-- Helpers to create Eval_Result values to wrap integers
function Create_Real_Result
(Expr_Type : LAL.Base_Type_Decl;
Value : Rational) return Eval_Result;
-- Helper to create Eval_Result values to wrap real numbers
function Create_Bool_Result
(Value : Boolean; N : LAL.Ada_Node'Class) return Eval_Result;
-- Helper to create an Eval_Result with Enum_Lit_Kind which denotes
-- the standard True or False literal decls from the standard Boolean
-- type.
-- todo: N is only used to access the fake free function P_Std_Entity.
function Create_Result_From_Subst
(Expr_Type : LAL.Base_Type_Decl;
Value : Big_Integer) return Eval_Result;
-- Helper to create Eval_Result values from a given substitution value.
-- The resulting Eval_Result's Kind will depend on the given Expr_Type:
-- - If the Expr_Type is an rnum Type, the Kind will be Enum_Lit.
-- - If the Expr_Type is a real Type, the Kind will be Real.
-- - If the Expr_Type is a integer Type, the Kind will be Int.
procedure Raise_To_N (Left, Right : Big_Integer; Result : out Big_Integer);
-- Raise Left to the power of Right and return the result. If Right is too
-- big or if it is negative, raise a Property_Error.
function To_Integer (Big_Int : Big_Integer) return Integer;
-- Convert a Big_Integer to an Integer
function As_Bool (Self : Eval_Result) return Boolean;
-- Return ``Self`` as a Boolean, if it is indeed of type
-- ``Standard.Boolean``.
function Is_Std_Char_Type (Node : LAL.Base_Type_Decl) return Boolean;
-- Return whether ``Node`` is a standard character type
----------------------
-- Is_Std_Char_Type --
----------------------
function Is_Std_Char_Type (Node : LAL.Base_Type_Decl) return Boolean is
begin
-- Note: The condition below was previously implemented with
-- a membership expression ``Node_Type in Std_Char_Type | ...``
-- but Ada specifies that the predefined `"="` operator must be
-- used in that case even if user-defined operator hides it.
-- However, the predefined operator is too strict for us in
-- this case: we want the comparison to discard irrelevant
-- metadata (like how the node was retrieved) and so need to
-- make sure the custom equality operators are called instead.
return (Node = Node.P_Std_Char_Type
or else Node = Node.P_Std_Wide_Char_Type
or else Node = Node.P_Std_Wide_Wide_Char_Type);
end Is_Std_Char_Type;
------------------------
-- Create_Enum_Result --
------------------------
function Create_Enum_Result
(Expr_Type : LAL.Base_Type_Decl;
Value : LAL.Enum_Literal_Decl) return Eval_Result is
begin
return ((Kind => Enum_Lit,
Expr_Type => Expr_Type,
Enum_Result => Value));
end Create_Enum_Result;
-----------------------
-- Create_Int_Result --
-----------------------
function Create_Int_Result
(Expr_Type : LAL.Base_Type_Decl;
Value : Big_Integer) return Eval_Result is
begin
return Result : Eval_Result :=
(Kind => Int, Expr_Type => Expr_Type, Int_Result => <>)
do
Result.Int_Result.Set (Value);
end return;
end Create_Int_Result;
function Create_Int_Result
(Expr_Type : LAL.Base_Type_Decl;
Value : Integer) return Eval_Result is
begin
return Create_Int_Result
(Expr_Type, GNATCOLL.GMP.Integers.Make (Integer'Image (Value)));
end Create_Int_Result;
------------------------
-- Create_Real_Result --
------------------------
function Create_Real_Result
(Expr_Type : LAL.Base_Type_Decl;
Value : Rational) return Eval_Result is
begin
return Result : Eval_Result :=
(Kind => Real, Expr_Type => Expr_Type, Real_Result => <>)
do
Result.Real_Result.Set (Value);
end return;
end Create_Real_Result;
------------------------------
-- Create_Result_From_Subst --
------------------------------
function Create_Result_From_Subst
(Expr_Type : LAL.Base_Type_Decl;
Value : Big_Integer) return Eval_Result is
begin
if Expr_Type.P_Is_Enum_Type then
declare
Base_Type_Decl : constant LAL.Type_Decl :=
P_Base_Subtype (Expr_Type).As_Type_Decl;
Enum_Def : constant LAL.Enum_Type_Def :=
F_Type_Def (Base_Type_Decl).As_Enum_Type_Def;
begin
return Create_Enum_Result
(Expr_Type,
Child
(F_Enum_Literals (Enum_Def),
Positive (To_Integer (Value) + 1)).As_Enum_Literal_Decl);
end;
end if;
return Create_Int_Result (Expr_Type, Value);
end Create_Result_From_Subst;
------------------------
-- Create_Bool_Result --
------------------------
function Create_Bool_Result
(Value : Boolean; N : LAL.Ada_Node'Class) return Eval_Result
is
-- Get the standard Boolean type declaration
Bool_Type : constant LAL.Base_Type_Decl :=
N.P_Std_Entity (+"Boolean").As_Base_Type_Decl;
begin
-- Get the enumerator value declaration corresponding to
-- Result in Standard's Boolean.
return Create_Enum_Result
(Bool_Type,
N.P_Std_Entity (+To_Text (Value'Image))
.As_Enum_Literal_Decl);
end Create_Bool_Result;
----------------
-- Raise_To_N --
----------------
procedure Raise_To_N (Left, Right : Big_Integer; Result : out Big_Integer)
is
N : Unsigned_Long;
begin
if Right < 0 then
raise Property_Error with "Exponent must be positive";
end if;
begin
N := Unsigned_Long'Value (Right.Image);
exception
when Constraint_Error =>
raise Property_Error with "Exponent is too large";
end;
Result.Set (Left ** N);
end Raise_To_N;
----------------
-- To_Integer --
----------------
function To_Integer (Big_Int : Big_Integer) return Integer is
begin
return Integer'Value (Big_Int.Image);
exception
when Constraint_Error =>
raise Property_Error with "out of range big integer";
end To_Integer;
---------------
-- Expr_Eval --
---------------
function Expr_Eval (E : LAL.Expr) return Eval_Result is
begin
return Expr_Eval_In_Env (E, (1 .. 0 => <>));
end Expr_Eval;
----------------------
-- Expr_Eval_In_Env --
----------------------
function Expr_Eval_In_Env
(E : LAL.Expr; Env : LAL.Substitution_Array) return Eval_Result
is
type Range_Attr is (Range_First, Range_Last);
-- Reference to either the 'First or the 'Last attribute
function Eval_Decl (D : LAL.Basic_Decl) return Eval_Result;
-- Helper to evaluate the value associated to a declaration
function Eval_Range_Attr
(D : LAL.Ada_Node; A : Range_Attr) return Eval_Result;
-- Helper to evaluate a 'First or 'Last attribute reference
function Eval_Function_Attr
(AR : LAL.Attribute_Ref; Args : LAL.Assoc_List) return Eval_Result;
-- Helper to evaluate function attribute references
function Eval_Array_Index
(Call_Expr : LAL.Call_Expr; Index : LAL.Expr) return Eval_Result;
-- Helper to evaluate array indexes
function Eval_Array_Slice
(Call_Expr : LAL.Call_Expr; Bounds : LAL.Bin_Op) return Eval_Result;
-- Helper to evaluate function attribute references
function Expr_Eval (E : LAL.Expr) return Eval_Result;
-- Helper to evaluate the given expr in the current environment. Note
-- that this is a regular function (instead of an expression function)
-- to workaround a GNAT bug.
---------------
-- Eval_Decl --
---------------
function Eval_Decl (D : LAL.Basic_Decl) return Eval_Result is
begin
if D.Is_Null then
raise Property_Error with "Invalid decl";
end if;
-- Check if the environment contains a substitution for the given
-- basic declaration. If so, return the value from the substitution.
for Subst of Env loop
if From_Decl (Subst) = D then
return Create_Result_From_Subst
(Expr_Type => Value_Type (Subst).As_Base_Type_Decl,
Value => To_Value (Subst));
end if;
end loop;
case D.Kind is
when Ada_Enum_Literal_Decl =>
-- An enum literal declaration evaluates to itself
return (Enum_Lit,
D.As_Enum_Literal_Decl.P_Enum_Type.As_Base_Type_Decl,
D.As_Enum_Literal_Decl);
when Ada_Synthetic_Char_Enum_Lit =>
-- A synthesized character enum declaration evaluates to the
-- evaluation of its expression.
return Expr_Eval
(D.As_Synthetic_Char_Enum_Lit.P_Expr.As_Expr);
when Ada_Number_Decl =>
-- A number declaration evaluates to the evaluation of its
-- expression.
return Expr_Eval (D.As_Number_Decl.F_Expr);
when Ada_Object_Decl_Range =>
if not D.As_Object_Decl.F_Renaming_Clause.Is_Null then
return Expr_Eval
(D.As_Object_Decl.F_Renaming_Clause
.F_Renamed_Object.As_Expr);
elsif not D.As_Object_Decl.F_Default_Expr.Is_Null then
return Expr_Eval (D.As_Object_Decl.F_Default_Expr);
else
raise Property_Error with "Object decl does not have "
& "a default expression nor a renaming clause.";
end if;
when Ada_Anonymous_Expr_Decl =>
return Expr_Eval (D.As_Anonymous_Expr_Decl.F_Expr);
when others =>
raise Property_Error
with "Cannot eval decl " & D.Kind'Image;
end case;
end Eval_Decl;
---------------------
-- Eval_Range_Attr --
---------------------
function Eval_Range_Attr
(D : LAL.Ada_Node; A : Range_Attr) return Eval_Result is
begin
if D.Is_Null then
raise Property_Error with "Cannot resolve attribute prefix";
end if;
case D.Kind is
when Ada_Name =>
return Eval_Range_Attr
(D.As_Name.P_Referenced_Decl.As_Ada_Node, A);
when Ada_Type_Decl =>
return Eval_Range_Attr
(D.As_Type_Decl.F_Type_Def.As_Ada_Node, A);
when Ada_Subtype_Decl =>
declare
Subtype_Indication : constant LAL.Subtype_Indication :=
D.As_Subtype_Decl.F_Subtype;
Constraint : constant LAL.Range_Constraint :=
Subtype_Indication.F_Constraint.As_Range_Constraint;
-- If the subtype declaration has a range constraint, evaluate
-- this constraint. Else, recurse on the designated subtype.
Target : constant LAL.Ada_Node :=
(if Constraint.Is_Null
then Subtype_Indication.P_Designated_Type_Decl.As_Ada_Node
else Constraint.F_Range.F_Range.As_Ada_Node);
begin
return Eval_Range_Attr (Target, A);
end;
when Ada_Bin_Op_Range =>
declare
BO : constant LAL.Bin_Op := D.As_Bin_Op;
Expr : constant LAL.Expr :=
(case A is
when Range_First => BO.F_Left,
when Range_Last => BO.F_Right);
begin
return Expr_Eval (Expr);
end;
when Ada_Type_Def =>
case D.Kind is
when Ada_Derived_Type_Def =>
declare
Cst : constant LAL.Constraint :=
D.As_Derived_Type_Def.F_Subtype_Indication.F_Constraint;
-- If the derived type declaration has a range constraint,
-- evaluate it. Otherwise, recurse on the base type.
Target : constant Ada_Node :=
(if Cst.Is_Null
then D.Parent.As_Base_Type_Decl.P_Base_Type.As_Ada_Node
else Cst.As_Range_Constraint.F_Range.F_Range.As_Ada_Node);
begin
return Eval_Range_Attr (Target, A);
end;
when Ada_Signed_Int_Type_Def =>
return Eval_Range_Attr
(D.As_Signed_Int_Type_Def.F_Range.F_Range.As_Ada_Node, A);
when Ada_Enum_Type_Def =>
declare
Lits : constant LAL.Enum_Literal_Decl_List :=
D.As_Enum_Type_Def.F_Enum_Literals;
Lit_Index : constant Positive :=
(case A is
when Range_First => Lits.First_Child_Index,
when Range_Last => Lits.Last_Child_Index);
Char_Pos : Natural;
begin
if Is_Std_Char_Type (D.Parent.As_Base_Type_Decl) then
-- Due to how we define the Character type in our
-- artifical __standard unit (and its
-- Wide_Character and Wide_Wide_Character
-- variants), the 'First and 'Last attributes cannot
-- return an Enum_Literal_Decl since they are not
-- defined. In order to not fail the Eval_As_Int
-- function, we return the corresponding Integer
-- value instead.
Char_Pos :=
(case A is
when Range_First =>
Support.Text.Character_Type'Pos
(Support.Text.Character_Type'First),
when Range_Last =>
(if D.P_Std_Char_Type
.As_Base_Type_Decl = D.Parent.As_Base_Type_Decl
then
Character'Pos (Character'Last)
elsif D.P_Std_Wide_Char_Type
.As_Base_Type_Decl =
D.Parent.As_Base_Type_Decl
then
Wide_Character'Pos (Wide_Character'Last)
else
Support.Text.Character_Type'Pos
(Support.Text.Character_Type'Last)));
return Create_Int_Result (D.Parent.As_Base_Type_Decl,
Char_Pos);
else
return Eval_Decl (Lits.Child (Lit_Index).As_Basic_Decl);
end if;
end;
when Ada_Decimal_Fixed_Point_Def =>
declare
Def : constant LAL.Decimal_Fixed_Point_Def :=
D.As_Decimal_Fixed_Point_Def;
Rng : constant LAL.Range_Spec := Def.F_Range;
begin
-- If a range has been specified we simply recurse on it,
-- otherwise we need to manually compute its bounds using
-- the `digits` and `delta` values specified for this fixed
-- point type definition.
if Rng.Is_Null then
declare
Delta_Res : constant Eval_Result :=
Expr_Eval (Def.F_Delta);
Delta_Val : constant Double :=
(if Delta_Res.Kind in Real
then Delta_Res.Real_Result.To_Double
else raise Property_Error with
"delta must be real");
Digits_Res : constant Eval_Result :=
Expr_Eval (Def.F_Digits);
Digits_Val : constant Integer :=
(if Digits_Res.Kind in Int
then To_Integer (Digits_Res.Int_Result)
else raise Property_Error with
"digits must be an integer");
Bound : constant Double :=
(if Digits_Val > 0 and Delta_Val > 0.0
then (10.0 ** Digits_Val - 1.0) * Delta_Val
else raise Property_Error with
"delta and digits must be positive");
begin
return Result : Eval_Result :=
(Kind => Real,
Expr_Type => D.Parent.As_Base_Type_Decl,
Real_Result => <>)
do
Result.Real_Result.Set
(case A is
when Range_First => -Bound,
when Range_Last => Bound);
end return;
end;
else
return Eval_Range_Attr (Rng.F_Range.As_Ada_Node, A);
end if;
end;
when Ada_Ordinary_Fixed_Point_Def =>
return Eval_Range_Attr
(D.As_Ordinary_Fixed_Point_Def.F_Range.F_Range.As_Ada_Node,
A);
when others =>
raise Property_Error with
"Cannot get " & A'Image & " attribute of type def "
& D.Kind'Image;
end case;
when Ada_Object_Decl =>
declare
Val : constant Eval_Result := Eval_Decl (D.As_Basic_Decl);
Typ : constant LAL.Base_Type_Decl :=
D.As_Object_Decl.P_Type_Expression.P_Designated_Type_Decl;
Result : Big_Integer;
begin
if Val.Kind /= String_Lit then
raise Property_Error with
"Cannot eval " & A'Image & " on " & Val.Kind'Image;
end if;
case A is
when Range_First => Result.Set (GNATCOLL.GMP.Long (Val.First));
when Range_Last => Result.Set (GNATCOLL.GMP.Long (Val.Last));
end case;
return Create_Int_Result (Typ, Result);
end;
when others =>
raise Property_Error with
"Cannot eval " & A'Image & " attribute of " & D.Kind'Image;
end case;
end Eval_Range_Attr;
------------------------
-- Eval_Function_Attr --
------------------------
function Eval_Function_Attr
(AR : LAL.Attribute_Ref; Args : LAL.Assoc_List) return Eval_Result
is
Attr : constant LAL.Identifier := AR.F_Attribute;
Name : constant Wide_Wide_String :=
Canonicalize (Attr.Text).Symbol;
begin
if Name in "min" | "max" then
if Args.Is_Null or else Args.Children_Count /= 2 then
raise Property_Error with
"'Min/'Max require exactly two arguments";
end if;
declare
Typ : constant Base_Type_Decl :=
AR.F_Prefix.P_Name_Designated_Type;
Val_1 : constant Eval_Result :=
Expr_Eval (Args.Child (1).As_Param_Assoc.F_R_Expr);
Val_2 : constant Eval_Result :=
Expr_Eval (Args.Child (2).As_Param_Assoc.F_R_Expr);
begin
if Val_1.Kind /= Val_2.Kind then
raise Property_Error with
"Inconsistent inputs for 'Min/'Max";
end if;
case Val_1.Kind is
when Int =>
if Name = "min" then
return Create_Int_Result
(Typ,
Eval_Result'
(if Val_1.Int_Result < Val_2.Int_Result
then Val_1 else Val_2).Int_Result);
else
return Create_Int_Result
(Typ,
Eval_Result'
(if Val_1.Int_Result > Val_2.Int_Result
then Val_1 else Val_2).Int_Result);
end if;
when Real =>
if Name = "min" then
return Create_Real_Result
(Typ,
Eval_Result'
(if Val_1.Real_Result < Val_2.Real_Result
then Val_1 else Val_2).Real_Result);
else
return Create_Real_Result
(Typ,
Eval_Result'
(if Val_1.Real_Result > Val_2.Real_Result
then Val_1 else Val_2).Real_Result);
end if;
when others =>
raise Property_Error with
"'Min/'Max not applicable on enum types";
end case;
end;
elsif Name in "succ" | "pred" then
if Args.Is_Null or else Args.Children_Count /= 1 then
raise Property_Error with
"'Pred/'Succ require exactly one argument";
end if;
declare
Typ : constant Base_Type_Decl :=
AR.F_Prefix.P_Name_Designated_Type;
Val : constant Eval_Result :=
Expr_Eval (Args.Child (1).As_Param_Assoc.F_R_Expr);
Enum_Val : Enum_Literal_Decl;
begin
case Val.Kind is
when Int =>
-- TODO??? Properly handle modular types
return Create_Int_Result
(Typ,
(if Name = "succ"
then Val.Int_Result + 1
else Val.Int_Result - 1));
when Real =>
raise Property_Error with
"'Pred/'Succ not applicable to reals";
when others =>
Enum_Val := Ada_Node'
(if Name = "succ"
then Val.Enum_Result.Next_Sibling
else Val.Enum_Result.Previous_Sibling)
.As_Enum_Literal_Decl;
if Enum_Val.Is_Null then
raise Property_Error with
"out of bounds 'Pred/'Succ on enum";
end if;
return Create_Enum_Result (Typ, Enum_Val);
end case;
end;
elsif Name in "val" then
if Args.Is_Null or Args.Children_Count /= 1 then
raise Property_Error with
"'Val require exactly one argument";
end if;
declare
Typ : constant Base_Type_Decl :=
AR.F_Prefix.P_Name_Designated_Type;
Val : constant Eval_Result :=
Expr_Eval (Args.Child (1).As_Param_Assoc.F_R_Expr);
begin
if Val.Kind /= Int then
raise Property_Error with
"'Val expects an integer argument";
end if;
if Typ.P_Is_Int_Type then
return Create_Int_Result (Typ, Val.Int_Result);
elsif Typ.P_Is_Enum_Type then
declare
Index : constant Integer :=
To_Integer (Val.Int_Result);
Enum_Val : Enum_Literal_Decl :=
No_Enum_Literal_Decl;
Root_Type : constant LAL.Base_Type_Decl :=
Typ.P_Root_Type;
begin
if Index > -1 then
if (Index <= Character'Pos (Character'Last)
and then Root_Type = Typ.P_Std_Char_Type)
or else (Index <= Wide_Character'Pos
(Wide_Character'Last)
and then Root_Type =
Typ.P_Std_Wide_Char_Type)
or else Root_Type = Typ.P_Std_Wide_Wide_Char_Type
-- Do not need to check for Wide_Wide_Character'Last
-- here, a runtime exception will be raised if Index
-- is out of range.
then
-- Due to how we define the Character type in our
-- artifical __standard unit (and its
-- Wide_Character and Wide_Wide_Character
-- variants), the 'Val attribute cannot return an
-- Enum_Literal_Decl since they are not defined. In
-- order to not fail the Eval_As_Int function, we
-- return the corresponding Integer value instead.
return Create_Int_Result (Typ, Val.Int_Result);
end if;
Enum_Val := Child
(Root_Type.As_Type_Decl.F_Type_Def.As_Enum_Type_Def
.F_Enum_Literals, Index + 1).As_Enum_Literal_Decl;
end if;
if Enum_Val.Is_Null then
raise Property_Error with
"out of bounds 'Val on enum";
end if;
return Create_Enum_Result (Typ, Enum_Val);
end;
else
raise Property_Error with
"'Val only applicable to scalar types";
end if;
end;
elsif Name in "pos" then
if Args.Is_Null or Args.Children_Count /= 1 then
raise Property_Error with
"'Pos require exactly one argument";
end if;
declare
Typ : constant Base_Type_Decl :=
AR.F_Prefix.P_Name_Designated_Type;
Ret_Typ : constant Base_Type_Decl :=
AR.P_Universal_Int_Type.As_Base_Type_Decl;
Val : constant Eval_Result :=
Expr_Eval (Args.Child (1).As_Param_Assoc.F_R_Expr);
begin
if Typ.P_Is_Int_Type then
if Val.Kind /= Int then
raise Property_Error with
"'Pos expects an integer argument";
end if;
-- The evaluator doesn't check if Pos argument is in the
-- range of Typ, i.e., illegal code such as:
-- Positive'Pos (-2)
-- will return -2.
return Create_Int_Result (Ret_Typ, Val.Int_Result);
elsif Typ.P_Is_Enum_Type then
case Val.Kind is
when Int =>
return Create_Int_Result (Ret_Typ, Val.Int_Result);
-- This case allows to support Character enum literals
when Enum_Lit =>
return Create_Int_Result
(Ret_Typ, Val.Enum_Result.P_Enum_Rep);
when others =>
raise Property_Error with
"'Pos expects an argument of a discrete type";
end case;
else
raise Property_Error with
"'Pos only applicable to discrete types";
end if;
end;
elsif Name in "length" then
-- Current support of 'Length only works on Strings (Character
-- arrays). TODO??? Add support for all array types, including
-- multidimensional ones.
if not Args.Is_Null then
raise Property_Error with
"'Length require no argument";
end if;
-- Not true for multidimensional arrays. 'Length attribute can
-- take one argument standing for the Nth dimension of the
-- array length is requested.
declare
Typ : constant Base_Type_Decl :=
AR.F_Prefix.P_Name_Designated_Type;
Val : constant Eval_Result :=
Expr_Eval
(AR.F_Prefix.P_Referenced_Decl
.As_Object_Decl.F_Default_Expr);
Result : Big_Integer;
begin
if Val.Kind /= String_Lit then
raise Property_Error with
"'Length expects a string argument";
end if;
Result.Set (GNATCOLL.GMP.Long (Length (As_String (Val))));
return Create_Int_Result (Typ, Result);
end;
else
raise Property_Error
with "Unhandled attribute ref: " & Image (Attr.Text);
end if;
end Eval_Function_Attr;
----------------------
-- Eval_Array_Index --
----------------------
function Eval_Array_Index
(Call_Expr : LAL.Call_Expr; Index : LAL.Expr) return Eval_Result
is
Array_Val : constant Eval_Result :=
Eval_Decl (Call_Expr.P_Referenced_Decl);
Index_Val : constant Eval_Result := Expr_Eval (Index);
use GNATCOLL.GMP.Integers.Misc;
begin
if Array_Val.Kind = String_Lit then
declare
Str : constant Unbounded_Text_Type := As_String (Array_Val);
Index : constant Integer :=
Integer (As_Signed_Long (Index_Val.Int_Result));
begin
return Create_Int_Result
(Call_Expr.P_Expression_Type.P_Comp_Type,
Wide_Wide_Character'Pos (Element (Str, Index)));
end;
else
raise Property_Error with
"Cannot eval array index of kind " & Array_Val.Kind'Image;
end if;
end Eval_Array_Index;
----------------------
-- Eval_Array_Slice --
----------------------
function Eval_Array_Slice
(Call_Expr : LAL.Call_Expr; Bounds : LAL.Bin_Op) return Eval_Result
is
Array_Val : constant Eval_Result :=
Eval_Decl (Call_Expr.P_Referenced_Decl);
First_Val : constant Eval_Result := Expr_Eval (Bounds.F_Left);
Last_Val : constant Eval_Result := Expr_Eval (Bounds.F_Right);
use GNATCOLL.GMP.Integers.Misc;
begin
if Array_Val.Kind = String_Lit then
declare
Str : Unbounded_Text_Type := As_String (Array_Val);
First : constant Integer :=
Integer (As_Signed_Long (First_Val.Int_Result));
Last : constant Integer :=
Integer (As_Signed_Long (Last_Val.Int_Result));
Len : constant Positive := Length (Str);
begin
if First < Last then
-- Adjust Str regarding to requested bounds
Delete (Str, Len - (Array_Val.Last - Last - 1), Len);
Delete (Str, 1, First - Array_Val.First);
else
-- The empty string
Delete (Str, 1, Len);
end if;
return (String_Lit, Call_Expr.P_Expression_Type,
Str, First, Last);
end;
else
raise Property_Error with
"Cannot eval array slide of kind " & Array_Val.Kind'Image;
end if;
end Eval_Array_Slice;
---------------
-- Expr_Eval --
---------------
function Expr_Eval (E : LAL.Expr) return Eval_Result is
begin
return Expr_Eval_In_Env (E, Env);
end Expr_Eval;
begin
-- Processings on invalid Ada sources may lead to calling Expr_Eval on a
-- null node. In this case, regular Ada runtime checks in code below
-- will trigger a Constraint_Error, while we want here to propagate
-- Property_Error exceptions on invalid code. So do the check ourselves.
if E.Is_Null then
raise Property_Error with "attempt to evaluate a null node";
end if;
case E.Kind is
when Ada_Identifier | Ada_Dotted_Name =>
return Eval_Decl (E.As_Name.P_Referenced_Decl);
when Ada_Char_Literal =>
declare
Char : constant LAL.Char_Literal := E.As_Char_Literal;
Node_Type : constant LAL.Base_Type_Decl :=
Char.P_Expression_Type.P_Root_Type;
begin
-- A character literal is an enum value like any other and so
-- its value should be its position in the enum. However, due
-- to how we define our artificial __standard unit, this
-- assumption does not hold for the Character type and its
-- variants (Wide_Character, etc.) as they are not defined in
-- their exact shape. We must therefore implement a specific
-- path to handle them here.
if Is_Std_Char_Type (Node_Type) then
-- Note that Langkit_Support's Character_Type is a
-- Wide_Wide_Character which can therefore also be used to
-- handle the Character and Wide_Character types.
return Create_Int_Result
(Char.P_Expression_Type,
Support.Text.Character_Type'Pos
(Char.P_Denoted_Value));
else
-- If it's not a standard character type, evaluate it just
-- as any other enum literal.
return Eval_Decl (Char.P_Referenced_Decl);
end if;
end;
when Ada_Int_Literal =>
return (Int,
E.P_Universal_Int_Type.As_Base_Type_Decl,
E.As_Int_Literal.P_Denoted_Value);
when Ada_Real_Literal =>
return Result : Eval_Result :=
(Kind => Real,
Expr_Type => E.P_Universal_Real_Type.As_Base_Type_Decl,
Real_Result => <>)
do
Decode_Real_Literal (E.Text, Result.Real_Result);
end return;
when Ada_String_Literal =>
declare
Val : constant Unbounded_Text_Type :=
+E.As_String_Literal.P_Denoted_Value;
begin
return (String_Lit, E.P_Expression_Type, Val, 1, Length (Val));
end;
when Ada_Membership_Expr =>
declare
MB : constant LAL.Membership_Expr :=
E.As_Membership_Expr;
Result : Boolean := False;
Op : constant LAL.Op := F_Op (MB);
Alts : constant LAL.Expr_Alternatives_List :=
F_Membership_Exprs (MB);
Choice_Value : constant Big_Integer := As_Int
(Expr_Eval (F_Expr (MB)));
begin
for C of Alts.Children loop
Result := Result or else P_Choice_Match (C, Choice_Value);
end loop;
if Op.Kind = Ada_Op_Not_In then
Result := not Result;
end if;
return Create_Bool_Result (Result, E.As_Ada_Node);
end;
when Ada_Relation_Op =>
declare
function Bool (X : Boolean; N : LAL.Ada_Node'Class := E)
return Eval_Result renames Create_Bool_Result;
BO : constant LAL.Bin_Op := E.As_Bin_Op;
Op : constant LAL.Op := BO.F_Op;
L : constant Eval_Result := Expr_Eval (BO.F_Left);
R : constant Eval_Result := Expr_Eval (BO.F_Right);
begin
if L.Kind /= R.Kind then
raise Property_Error with "Unsupported type discrepancy";
end if;
case R.Kind is
when Int =>
case Op.Kind is
when Ada_Op_Eq =>
return Bool (L.Int_Result = R.Int_Result);
when Ada_Op_Neq =>
return Bool (L.Int_Result /= R.Int_Result);
when Ada_Op_Lt =>
return Bool (L.Int_Result < R.Int_Result);
when Ada_Op_Lte =>
return Bool (L.Int_Result <= R.Int_Result);
when Ada_Op_Gt =>
return Bool (L.Int_Result > R.Int_Result);
when Ada_Op_Gte =>
return Bool (L.Int_Result >= R.Int_Result);
when others =>
raise Program_Error with "Impossible path";
end case;
when Real =>
case Op.Kind is
when Ada_Op_Eq =>
return Bool (L.Real_Result = R.Real_Result);
when Ada_Op_Neq =>
return Bool (L.Real_Result /= R.Real_Result);
when Ada_Op_Lt =>
return Bool (L.Real_Result < R.Real_Result);
when Ada_Op_Lte =>
return Bool (L.Real_Result <= R.Real_Result);
when Ada_Op_Gt =>
return Bool (L.Real_Result > R.Real_Result);
when Ada_Op_Gte =>
return Bool (L.Real_Result >= R.Real_Result);
when others =>
raise Program_Error with "Impossible path";
end case;
when Enum_Lit =>
case Op.Kind is
when Ada_Op_Eq =>
return Bool (L.Enum_Result = R.Enum_Result);
when Ada_Op_Neq =>
return Bool (L.Enum_Result /= R.Enum_Result);
when others =>
raise Property_Error with
"Unhandled relation operator on enum values: "
& Op.Kind'Image;
end case;
when String_Lit =>
case Op.Kind is
when Ada_Op_Eq =>
return Bool
(Langkit_Support.Text."="
(L.String_Result, R.String_Result));
when Ada_Op_Neq =>
return Bool
(Langkit_Support.Text."/="
(L.String_Result, R.String_Result));
when others =>
raise Property_Error with
"Unhandled relation operator on string values: "
& Op.Kind'Image;
end case;
end case;
end;
when Ada_Bin_Op =>
declare
BO : constant LAL.Bin_Op := E.As_Bin_Op;
Op : constant LAL.Op := BO.F_Op;
L : constant Eval_Result := Expr_Eval (BO.F_Left);
R : constant Eval_Result := Expr_Eval (BO.F_Right);
begin
if L.Kind /= R.Kind then
if L.Kind = Int and then R.Kind = Real
and then Op.Kind = Ada_Op_Mult
then
declare
Result : Rational;
Left : Rational;
begin
Left.Set (L.Int_Result);
Result.Set (Left * R.Real_Result);
return Create_Real_Result (R.Expr_Type, Result);
end;
elsif L.Kind = Real and then R.Kind = Int
and then Op.Kind = Ada_Op_Mult
then
declare
Result : Rational;
Right : Rational;
begin
Right.Set (R.Int_Result);
Result.Set (L.Real_Result * Right);
return Create_Real_Result (L.Expr_Type, Result);
end;
elsif L.Kind = Real and then R.Kind = Int
and then Op.Kind = Ada_Op_Div
then
declare
Result : Rational;
Right : Rational;
begin
Right.Set (R.Int_Result);
Result.Set (L.Real_Result / Right);
return Create_Real_Result (L.Expr_Type, Result);
end;
elsif L.Kind = Real and then R.Kind = Int
and then Op.Kind = Ada_Op_Pow
then
declare
Result : Rational;
begin
Result.Set (L.Real_Result ** R.Int_Result);
return Create_Real_Result (L.Expr_Type, Result);
end;
else
raise Property_Error with "Unsupported type discrepancy";
end if;
end if;
case R.Kind is
when Int =>
-- Handle arithmetic operators on Int values
declare
Result : Big_Integer;
begin
case Op.Kind is
when Ada_Op_Plus =>
Result.Set (L.Int_Result + R.Int_Result);
when Ada_Op_Minus =>
Result.Set (L.Int_Result - R.Int_Result);
when Ada_Op_Mult =>
Result.Set (L.Int_Result * R.Int_Result);
when Ada_Op_Div =>
if R.Int_Result = 0 then
raise Property_Error with "Division by zero";
end if;
Result.Set (L.Int_Result / R.Int_Result);
when Ada_Op_Pow =>
Raise_To_N (L.Int_Result, R.Int_Result, Result);
when others =>
raise Property_Error with
"Unhandled operator: " & Op.Kind'Image;
end case;
return Create_Int_Result (R.Expr_Type, Result);
end;
when Real =>
-- Handle arithmetic operators on Real values
declare
Result : Rational;
begin
begin
case Op.Kind is
when Ada_Op_Plus =>
Result.Set (L.Real_Result + R.Real_Result);
when Ada_Op_Minus =>
Result.Set (L.Real_Result - R.Real_Result);
when Ada_Op_Mult =>
Result.Set (L.Real_Result * R.Real_Result);
when Ada_Op_Div =>
Result.Set (L.Real_Result / R.Real_Result);
when others =>
raise Property_Error with
"Unhandled operator: " & Op.Kind'Image;
end case;
exception
when Exc : Constraint_Error =>
raise Property_Error with
"Floating point computation error: "
& Ada.Exceptions.Exception_Message (Exc);
end;
return Create_Real_Result (R.Expr_Type, Result);
end;
when Enum_Lit =>
-- Handle relational operators on boolean values
declare
LB : constant Boolean := As_Bool (L);
RB : constant Boolean := As_Bool (R);
Result : Boolean;
begin
case Op.Kind is
when Ada_Op_And | Ada_Op_And_Then =>
Result := LB and then RB;
when Ada_Op_Or | Ada_Op_Or_Else =>
Result := LB or else RB;
when others =>
raise Property_Error with
"Wrong operator for boolean: " & Op.Kind'Image;
end case;
return Create_Bool_Result (Result, BO.As_Ada_Node);
end;
when String_Lit =>
raise Property_Error with
"Wrong operator for string: " & Op.Kind'Image;
end case;
end;
when Ada_Concat_Op =>
declare
CO : constant LAL.Concat_Op := E.As_Concat_Op;
Concat_Result : Unbounded_Text_Type;
First : Natural := 0;
begin
for I of CO.P_Operands loop
declare
ER : constant Eval_Result := Expr_Eval (I);
begin
if First = 0 then
First := ER.First;
end if;
Concat_Result := Concat_Result & ER.String_Result;
end;
end loop;
return
(String_Lit,
E.P_Expression_Type,
Concat_Result,
First,
First + Length (Concat_Result));
end;
when Ada_Un_Op =>
declare
UO : constant LAL.Un_Op := E.As_Un_Op;
Op : constant LAL.Op := UO.F_Op;
Operand_Val : constant Eval_Result := Expr_Eval (UO.F_Expr);
Operand_Type : LAL.Base_Type_Decl renames Operand_Val.Expr_Type;
subtype Valid_Unop_Kind is Ada_Node_Kind_Type with
Static_Predicate => Valid_Unop_Kind in
Ada_Op_Minus | Ada_Op_Plus | Ada_Op_Abs | Ada_Op_Not;
Op_Kind : constant Valid_Unop_Kind := Op.Kind;
-- Parsers can only build unary operators with the above
-- operations. Using a subtype here saves us from writing dead
-- code.
begin
case Operand_Val.Kind is
when Enum_Lit =>
-- Unary operators are not valid on enums. This is not a
-- legality check: since we process standard character types
-- as integers, this guard will not reject them, but at
-- least code below can assume we are dealing with integers
-- or reals.
raise Property_Error with
"Unary operator invalid on enumerations";
when String_Lit =>
raise Property_Error with
"Unary operator invalid on strings";
when Int =>
declare
Operand : Big_Integer renames Operand_Val.Int_Result;
Result : Big_Integer;
begin
case Op_Kind is
when Ada_Op_Minus =>
Result.Set (-Operand);
when Ada_Op_Plus =>
Result.Set (Operand);
when Ada_Op_Abs =>
Result.Set (abs Operand);
when Ada_Op_Not =>
-- TODO??? Here, we need to check that the operand
-- type is a modular type, and flip bits according to
-- its size.
raise Property_Error with
"""not"" not implemented yet";
end case;
return Create_Int_Result (Operand_Type, Result);
end;
when Real =>
declare
Operand : Rational renames Operand_Val.Real_Result;
Result : Rational;
begin
begin
case Op_Kind is
when Ada_Op_Minus =>
Result.Set (-Operand);
when Ada_Op_Plus =>
Result.Set (Operand);
when Ada_Op_Abs =>
Result.Set (abs Operand);
when Ada_Op_Not =>
raise Property_Error with
"Invalid ""not"" operator for floating point"
& " value";
end case;
exception
when Exc : Constraint_Error =>
raise Property_Error with
"Floating point computation error: "
& Ada.Exceptions.Exception_Message (Exc);
end;
return Create_Real_Result (Operand_Type, Result);
end;
end case;
end;
when Ada_Attribute_Ref =>
declare
AR : constant LAL.Attribute_Ref := E.As_Attribute_Ref;
Attr : constant LAL.Identifier := AR.F_Attribute;
Name : constant Wide_Wide_String :=
Canonicalize (Attr.Text).Symbol;
begin
if Name = "first" then
return Eval_Range_Attr
(As_Ada_Node (AR.F_Prefix), Range_First);
elsif Name = "last" then
return Eval_Range_Attr
(As_Ada_Node (AR.F_Prefix), Range_Last);
else
return Eval_Function_Attr (AR, LAL.No_Assoc_List);
end if;
end;
when Ada_Paren_Expr =>
return Expr_Eval (E.As_Paren_Expr.F_Expr);
when Ada_Call_Expr =>
declare
C : constant Call_Expr := E.As_Call_Expr;
S : constant Ada_Node := C.F_Suffix;
Arg : Expr;
Designated_Type : constant Base_Type_Decl :=
C.F_Name.P_Name_Designated_Type;
C_Kind : Call_Expr_Kind;
begin
-- Make sure that C's name designates a type and that C has
-- exactly one argument.
if C.F_Name.Kind in Ada_Attribute_Ref then
return Eval_Function_Attr
(C.F_Name.As_Attribute_Ref, S.As_Assoc_List);
end if;
-- Avoid displaying LAL's internal property errors on calls to
-- P_Kind when evaluating invalid code.
begin
C_Kind := C.P_Kind;
exception
when Property_Error =>
raise Property_Error with
"Unhandled call expr: " & Image (E.Text);
end;
if C_Kind in Array_Index then
return Eval_Array_Index
(C, S.Child (1).As_Param_Assoc.F_R_Expr);
elsif C_Kind in Array_Slice then
return Eval_Array_Slice
(C, S.As_Bin_Op);
elsif Designated_Type.Is_Null
or else S.Is_Null
or else S.Children_Count /= 1
then
raise Property_Error
with "Unhandled call expr: " & Image (E.Text);
end if;
Arg := S.Child (1).As_Param_Assoc.F_R_Expr;
if Designated_Type.P_Is_Float_Type then
declare
Arg_Val : constant Eval_Result := Expr_Eval (Arg);
Result : Rational;
begin
case Arg_Val.Kind is
when Int =>
Result.Set (Arg_Val.Int_Result);
when Real =>
Result.Set (Arg_Val.Real_Result);
when Enum_Lit =>
raise Property_Error with "Invalid enum argument";
when String_Lit =>
raise Property_Error with "Invalid string argument";
end case;
return Create_Real_Result (Designated_Type, Result);
end;
elsif Designated_Type.P_Is_Int_Type then
declare
Arg_Val : constant Eval_Result := Expr_Eval (Arg);
Result : Big_Integer;
begin
case Arg_Val.Kind is
when Int =>
Result.Set (Arg_Val.Int_Result);
when Real =>
Result.Set
(GNATCOLL.GMP.Long (Arg_Val.Real_Result.To_Double));
when Enum_Lit =>
raise Property_Error with "Invalid enum argument";
when String_Lit =>
raise Property_Error with "Invalid string argument";
end case;
return Create_Int_Result (Designated_Type, Result);
end;
elsif Designated_Type.P_Is_Enum_Type then
declare
Arg_Val : constant Eval_Result := Expr_Eval (Arg);
begin
case Arg_Val.Kind is
when Int =>
raise Property_Error with "Invalid integer argument";
when Real =>
raise Property_Error with "Invalid real argument";
when Enum_Lit =>
-- Convert an enum to another enum: return Arg_Val
-- with its new type.
return Create_Enum_Result
(Designated_Type, Arg_Val.Enum_Result);
when String_Lit =>
raise Property_Error with "Invalid string argument";
end case;
end;
else
raise Property_Error
with "Unhandled type conversion: " & Image (E.Text);
end if;
end;
when others =>
raise Property_Error with "Unhandled node: " & E.Kind'Img;
end case;
end Expr_Eval_In_Env;
------------
-- As_Int --
------------
function As_Int (Self : Eval_Result) return Big_Integer is
begin
return Result : Big_Integer do
case Self.Kind is
when Int =>
Result.Set (Self.Int_Result);
when Real =>
raise Property_Error;
when Enum_Lit =>
declare
Pos : constant Natural := Self.Enum_Result.Child_Index;
begin
Result.Set (GNATCOLL.GMP.Long (Pos));
end;
when String_Lit =>
raise Property_Error;
end case;
end return;
end As_Int;
-------------
-- As_Bool --
-------------
function As_Bool (Self : Eval_Result) return Boolean is
Bool_Type : LAL.Base_Type_Decl;
begin
case Self.Kind is
when Enum_Lit =>
Bool_Type :=
Self.Enum_Result.P_Std_Entity (+"Boolean").As_Base_Type_Decl;
if Self.Expr_Type /= Bool_Type then
raise Property_Error with "Wrong type for enum for As_Bool";
end if;
return Self.Enum_Result.Text = "True";
when others =>
raise Property_Error with "Wrong value kind for As_Bool";
end case;
end As_Bool;
---------------
-- As_String --
---------------
function As_String (Self : Eval_Result) return Unbounded_Text_Type is
begin
case Self.Kind is
when Int =>
raise Property_Error;
when Real =>
raise Property_Error;
when Enum_Lit =>
raise Property_Error;
when String_Lit =>
return Self.String_Result;
end case;
end As_String;
-----------
-- Image --
-----------
function Image (Self : Eval_Result) return String is
begin
return "<Eval_Result "
& Self.Kind'Image & " "
& (case Self.Kind is
when Int => Self.Int_Result.Image,
when Real => Self.Real_Result.Image,
when Enum_Lit => Self.Enum_Result.Image,
when String_Lit => Encode (To_Text (Self.String_Result), "UTF-8"))
& ">";
end Image;
end Libadalang.Expr_Eval;
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