-- --
-- B o d y --
-- --
--- Copyright (C) 1992-2008, Free Software Foundation, Inc. --
+-- Copyright (C) 1992-2010, 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- --
with Errout; use Errout;
with Eval_Fat; use Eval_Fat;
with Exp_Util; use Exp_Util;
+with Freeze; use Freeze;
with Lib; use Lib;
with Namet; use Namet;
with Nmake; use Nmake;
with Nlists; use Nlists;
with Opt; use Opt;
with Sem; use Sem;
+with Sem_Aux; use Sem_Aux;
with Sem_Cat; use Sem_Cat;
with Sem_Ch6; use Sem_Ch6;
with Sem_Ch8; use Sem_Ch8;
-- This is the actual cache, with entries consisting of node/value pairs,
-- and the impossible value Node_High_Bound used for unset entries.
+ type Range_Membership is (In_Range, Out_Of_Range, Unknown);
+ -- Range membership may either be statically known to be in range or out
+ -- of range, or not statically known. Used for Test_In_Range below.
+
-----------------------
-- Local Subprograms --
-----------------------
-- used for producing the result of the static evaluation of the
-- logical operators
+ function Find_Universal_Operator_Type (N : Node_Id) return Entity_Id;
+ -- Check whether an arithmetic operation with universal operands which
+ -- is a rewritten function call with an explicit scope indication is
+ -- ambiguous: P."+" (1, 2) will be ambiguous if there is more than one
+ -- visible numeric type declared in P and the context does not impose a
+ -- type on the result (e.g. in the expression of a type conversion).
+ -- If ambiguous, emit an error and return Empty, else return the result
+ -- type of the operator.
+
procedure Test_Expression_Is_Foldable
(N : Node_Id;
Op1 : Node_Id;
-- it is not technically static (e.g. the static lower bound of a range
-- whose upper bound is non-static).
--
- -- If Stat is set False on return, then Expression_Is_Foldable makes a
+ -- If Stat is set False on return, then Test_Expression_Is_Foldable makes a
-- call to Check_Non_Static_Context on the operand. If Fold is False on
-- return, then all processing is complete, and the caller should
-- return, since there is nothing else to do.
+ --
+ -- If Stat is set True on return, then Is_Static_Expression is also set
+ -- true in node N. There are some cases where this is over-enthusiastic,
+ -- e.g. in the two operand case below, for string comparison, the result
+ -- is not static even though the two operands are static. In such cases,
+ -- the caller must reset the Is_Static_Expression flag in N.
procedure Test_Expression_Is_Foldable
(N : Node_Id;
-- Same processing, except applies to an expression N with two operands
-- Op1 and Op2.
+ function Test_In_Range
+ (N : Node_Id;
+ Typ : Entity_Id;
+ Assume_Valid : Boolean;
+ Fixed_Int : Boolean;
+ Int_Real : Boolean) return Range_Membership;
+ -- Common processing for Is_In_Range and Is_Out_Of_Range:
+ -- Returns In_Range or Out_Of_Range if it can be guaranteed at compile time
+ -- that expression N is known to be in or out of range of the subtype Typ.
+ -- If not compile time known, Unknown is returned.
+ -- See documentation of Is_In_Range for complete description of parameters.
+
procedure To_Bits (U : Uint; B : out Bits);
-- Converts a Uint value to a bit string of length B'Length
if not Is_Static_Expression (N) then
if Is_Floating_Point_Type (T)
- and then Is_Out_Of_Range (N, Base_Type (T))
+ and then Is_Out_Of_Range (N, Base_Type (T), Assume_Valid => True)
then
Error_Msg_N
("?float value out of range, infinity will be generated", N);
-- number, so as not to lose case where value overflows in the
-- least significant bit or less. See B490001.
- if Is_Out_Of_Range (N, Base_Type (T)) then
+ if Is_Out_Of_Range (N, Base_Type (T), Assume_Valid => True) then
Out_Of_Range (N);
return;
end if;
-- Check out of range of base type
- elsif Is_Out_Of_Range (N, Base_Type (T)) then
+ elsif Is_Out_Of_Range (N, Base_Type (T), Assume_Valid => True) then
Out_Of_Range (N);
- -- Give warning if outside subtype (where one or both of the
- -- bounds of the subtype is static). This warning is omitted
- -- if the expression appears in a range that could be null
- -- (warnings are handled elsewhere for this case).
+ -- Give warning if outside subtype (where one or both of the bounds of
+ -- the subtype is static). This warning is omitted if the expression
+ -- appears in a range that could be null (warnings are handled elsewhere
+ -- for this case).
elsif T /= Base_Type (T)
and then Nkind (Parent (N)) /= N_Range
then
- if Is_In_Range (N, T) then
+ if Is_In_Range (N, T, Assume_Valid => True) then
null;
- elsif Is_Out_Of_Range (N, T) then
+ elsif Is_Out_Of_Range (N, T, Assume_Valid => True) then
Apply_Compile_Time_Constraint_Error
(N, "value not in range of}?", CE_Range_Check_Failed);
--------------------------
function Compile_Time_Compare
- (L, R : Node_Id;
- Rec : Boolean := False) return Compare_Result
+ (L, R : Node_Id;
+ Assume_Valid : Boolean) return Compare_Result
+ is
+ Discard : aliased Uint;
+ begin
+ return Compile_Time_Compare (L, R, Discard'Access, Assume_Valid);
+ end Compile_Time_Compare;
+
+ function Compile_Time_Compare
+ (L, R : Node_Id;
+ Diff : access Uint;
+ Assume_Valid : Boolean;
+ Rec : Boolean := False) return Compare_Result
is
- Ltyp : constant Entity_Id := Etype (L);
- Rtyp : constant Entity_Id := Etype (R);
+ Ltyp : Entity_Id := Underlying_Type (Etype (L));
+ Rtyp : Entity_Id := Underlying_Type (Etype (R));
+ -- These get reset to the base type for the case of entities where
+ -- Is_Known_Valid is not set. This takes care of handling possible
+ -- invalid representations using the value of the base type, in
+ -- accordance with RM 13.9.1(10).
+
+ Discard : aliased Uint;
procedure Compare_Decompose
(N : Node_Id;
R : out Node_Id;
V : out Uint);
- -- This procedure decomposes the node N into an expression node
- -- and a signed offset, so that the value of N is equal to the
- -- value of R plus the value V (which may be negative). If no
- -- such decomposition is possible, then on return R is a copy
- -- of N, and V is set to zero.
+ -- This procedure decomposes the node N into an expression node and a
+ -- signed offset, so that the value of N is equal to the value of R plus
+ -- the value V (which may be negative). If no such decomposition is
+ -- possible, then on return R is a copy of N, and V is set to zero.
function Compare_Fixup (N : Node_Id) return Node_Id;
- -- This function deals with replacing 'Last and 'First references
- -- with their corresponding type bounds, which we then can compare.
- -- The argument is the original node, the result is the identity,
- -- unless we have a 'Last/'First reference in which case the value
- -- returned is the appropriate type bound.
+ -- This function deals with replacing 'Last and 'First references with
+ -- their corresponding type bounds, which we then can compare. The
+ -- argument is the original node, the result is the identity, unless we
+ -- have a 'Last/'First reference in which case the value returned is the
+ -- appropriate type bound.
+
+ function Is_Known_Valid_Operand (Opnd : Node_Id) return Boolean;
+ -- Even if the context does not assume that values are valid, some
+ -- simple cases can be recognized.
function Is_Same_Value (L, R : Node_Id) return Boolean;
-- Returns True iff L and R represent expressions that definitely
return;
elsif Nkind (N) = N_Attribute_Reference then
-
if Attribute_Name (N) = Name_Succ then
R := First (Expressions (N));
V := Uint_1;
else -- Attribute_Name (N) = Name_Last
return Make_Integer_Literal (Sloc (N),
Intval => Intval (String_Literal_Low_Bound (Xtyp))
- + String_Literal_Length (Xtyp));
+ + String_Literal_Length (Xtyp));
end if;
end if;
return N;
end Compare_Fixup;
+ ----------------------------
+ -- Is_Known_Valid_Operand --
+ ----------------------------
+
+ function Is_Known_Valid_Operand (Opnd : Node_Id) return Boolean is
+ begin
+ return (Is_Entity_Name (Opnd)
+ and then
+ (Is_Known_Valid (Entity (Opnd))
+ or else Ekind (Entity (Opnd)) = E_In_Parameter
+ or else
+ (Ekind (Entity (Opnd)) in Object_Kind
+ and then Present (Current_Value (Entity (Opnd))))))
+ or else Is_OK_Static_Expression (Opnd);
+ end Is_Known_Valid_Operand;
+
-------------------
-- Is_Same_Value --
-------------------
Rf : constant Node_Id := Compare_Fixup (R);
function Is_Same_Subscript (L, R : List_Id) return Boolean;
- -- L, R are the Expressions values from two attribute nodes
- -- for First or Last attributes. Either may be set to No_List
- -- if no expressions are present (indicating subscript 1).
- -- The result is True if both expressions represent the same
- -- subscript (note that one case is where one subscript is
- -- missing and the other is explicitly set to 1).
+ -- L, R are the Expressions values from two attribute nodes for First
+ -- or Last attributes. Either may be set to No_List if no expressions
+ -- are present (indicating subscript 1). The result is True if both
+ -- expressions represent the same subscript (note one case is where
+ -- one subscript is missing and the other is explicitly set to 1).
-----------------------
-- Is_Same_Subscript --
-- Start of processing for Is_Same_Value
begin
- -- Values are the same if they are the same identifier and the
- -- identifier refers to a constant object (E_Constant). This
- -- does not however apply to Float types, since we may have two
- -- NaN values and they should never compare equal.
+ -- Values are the same if they refer to the same entity and the
+ -- entity is non-volatile. This does not however apply to Float
+ -- types, since we may have two NaN values and they should never
+ -- compare equal.
+
+ -- If the entity is a discriminant, the two expressions may be bounds
+ -- of components of objects of the same discriminated type. The
+ -- values of the discriminants are not static, and therefore the
+ -- result is unknown.
+
+ -- It would be better to comment individual branches of this test ???
- if Nkind (Lf) = N_Identifier and then Nkind (Rf) = N_Identifier
+ if Nkind_In (Lf, N_Identifier, N_Expanded_Name)
+ and then Nkind_In (Rf, N_Identifier, N_Expanded_Name)
and then Entity (Lf) = Entity (Rf)
+ and then Ekind (Entity (Lf)) /= E_Discriminant
+ and then Present (Entity (Lf))
and then not Is_Floating_Point_Type (Etype (L))
- and then Is_Constant_Object (Entity (Lf))
+ and then not Is_Volatile_Reference (L)
+ and then not Is_Volatile_Reference (R)
then
return True;
then
return True;
- -- Or if they are both 'First or 'Last values applying to the
- -- same entity (first and last don't change even if value does)
+ -- False if Nkind of the two nodes is different for remaining cases
+
+ elsif Nkind (Lf) /= Nkind (Rf) then
+ return False;
+
+ -- True if both 'First or 'Last values applying to the same entity
+ -- (first and last don't change even if value does). Note that we
+ -- need this even with the calls to Compare_Fixup, to handle the
+ -- case of unconstrained array attributes where Compare_Fixup
+ -- cannot find useful bounds.
elsif Nkind (Lf) = N_Attribute_Reference
- and then
- Nkind (Rf) = N_Attribute_Reference
and then Attribute_Name (Lf) = Attribute_Name (Rf)
and then (Attribute_Name (Lf) = Name_First
or else
Attribute_Name (Lf) = Name_Last)
- and then Is_Entity_Name (Prefix (Lf))
- and then Is_Entity_Name (Prefix (Rf))
+ and then Nkind_In (Prefix (Lf), N_Identifier, N_Expanded_Name)
+ and then Nkind_In (Prefix (Rf), N_Identifier, N_Expanded_Name)
and then Entity (Prefix (Lf)) = Entity (Prefix (Rf))
and then Is_Same_Subscript (Expressions (Lf), Expressions (Rf))
then
return True;
- -- All other cases, we can't tell
+ -- True if the same selected component from the same record
+
+ elsif Nkind (Lf) = N_Selected_Component
+ and then Selector_Name (Lf) = Selector_Name (Rf)
+ and then Is_Same_Value (Prefix (Lf), Prefix (Rf))
+ then
+ return True;
+
+ -- True if the same unary operator applied to the same operand
+
+ elsif Nkind (Lf) in N_Unary_Op
+ and then Is_Same_Value (Right_Opnd (Lf), Right_Opnd (Rf))
+ then
+ return True;
+
+ -- True if the same binary operator applied to the same operands
+
+ elsif Nkind (Lf) in N_Binary_Op
+ and then Is_Same_Value (Left_Opnd (Lf), Left_Opnd (Rf))
+ and then Is_Same_Value (Right_Opnd (Lf), Right_Opnd (Rf))
+ then
+ return True;
+
+ -- All other cases, we can't tell, so return False
else
return False;
-- Start of processing for Compile_Time_Compare
begin
+ Diff.all := No_Uint;
+
-- If either operand could raise constraint error, then we cannot
-- know the result at compile time (since CE may be raised!)
if L = R then
return EQ;
- -- If expressions have no types, then do not attempt to determine
- -- if they are the same, since something funny is going on. One
- -- case in which this happens is during generic template analysis,
- -- when bounds are not fully analyzed.
+ -- If expressions have no types, then do not attempt to determine if
+ -- they are the same, since something funny is going on. One case in
+ -- which this happens is during generic template analysis, when bounds
+ -- are not fully analyzed.
elsif No (Ltyp) or else No (Rtyp) then
return Unknown;
- -- We only attempt compile time analysis for scalar values, and
- -- not for packed arrays represented as modular types, where the
- -- semantics of comparison is quite different.
+ -- We do not attempt comparisons for packed arrays arrays represented as
+ -- modular types, where the semantics of comparison is quite different.
- elsif not Is_Scalar_Type (Ltyp)
- or else Is_Packed_Array_Type (Ltyp)
+ elsif Is_Packed_Array_Type (Ltyp)
+ and then Is_Modular_Integer_Type (Ltyp)
then
return Unknown;
+ -- For access types, the only time we know the result at compile time
+ -- (apart from identical operands, which we handled already) is if we
+ -- know one operand is null and the other is not, or both operands are
+ -- known null.
+
+ elsif Is_Access_Type (Ltyp) then
+ if Known_Null (L) then
+ if Known_Null (R) then
+ return EQ;
+ elsif Known_Non_Null (R) then
+ return NE;
+ else
+ return Unknown;
+ end if;
+
+ elsif Known_Non_Null (L) and then Known_Null (R) then
+ return NE;
+
+ else
+ return Unknown;
+ end if;
+
-- Case where comparison involves two compile time known values
elsif Compile_Time_Known_Value (L)
end if;
end;
- -- For the integer case we know exactly (note that this includes the
- -- fixed-point case, where we know the run time integer values now)
+ -- For string types, we have two string literals and we proceed to
+ -- compare them using the Ada style dictionary string comparison.
+
+ elsif not Is_Scalar_Type (Ltyp) then
+ declare
+ Lstring : constant String_Id := Strval (Expr_Value_S (L));
+ Rstring : constant String_Id := Strval (Expr_Value_S (R));
+ Llen : constant Nat := String_Length (Lstring);
+ Rlen : constant Nat := String_Length (Rstring);
+
+ begin
+ for J in 1 .. Nat'Min (Llen, Rlen) loop
+ declare
+ LC : constant Char_Code := Get_String_Char (Lstring, J);
+ RC : constant Char_Code := Get_String_Char (Rstring, J);
+ begin
+ if LC < RC then
+ return LT;
+ elsif LC > RC then
+ return GT;
+ end if;
+ end;
+ end loop;
+
+ if Llen < Rlen then
+ return LT;
+ elsif Llen > Rlen then
+ return GT;
+ else
+ return EQ;
+ end if;
+ end;
+
+ -- For remaining scalar cases we know exactly (note that this does
+ -- include the fixed-point case, where we know the run time integer
+ -- values now).
else
declare
begin
if Lo < Hi then
+ Diff.all := Hi - Lo;
return LT;
+
elsif Lo = Hi then
return EQ;
+
else
+ Diff.all := Lo - Hi;
return GT;
end if;
end;
-- Cases where at least one operand is not known at compile time
else
- -- Remaining checks apply only for non-generic discrete types
+ -- Remaining checks apply only for discrete types
if not Is_Discrete_Type (Ltyp)
or else not Is_Discrete_Type (Rtyp)
- or else Is_Generic_Type (Ltyp)
- or else Is_Generic_Type (Rtyp)
then
return Unknown;
end if;
+ -- Defend against generic types, or actually any expressions that
+ -- contain a reference to a generic type from within a generic
+ -- template. We don't want to do any range analysis of such
+ -- expressions for two reasons. First, the bounds of a generic type
+ -- itself are junk and cannot be used for any kind of analysis.
+ -- Second, we may have a case where the range at run time is indeed
+ -- known, but we don't want to do compile time analysis in the
+ -- template based on that range since in an instance the value may be
+ -- static, and able to be elaborated without reference to the bounds
+ -- of types involved. As an example, consider:
+
+ -- (F'Pos (F'Last) + 1) > Integer'Last
+
+ -- The expression on the left side of > is Universal_Integer and thus
+ -- acquires the type Integer for evaluation at run time, and at run
+ -- time it is true that this condition is always False, but within
+ -- an instance F may be a type with a static range greater than the
+ -- range of Integer, and the expression statically evaluates to True.
+
+ if References_Generic_Formal_Type (L)
+ or else
+ References_Generic_Formal_Type (R)
+ then
+ return Unknown;
+ end if;
+
+ -- Replace types by base types for the case of entities which are
+ -- not known to have valid representations. This takes care of
+ -- properly dealing with invalid representations.
+
+ if not Assume_Valid and then not Assume_No_Invalid_Values then
+ if Is_Entity_Name (L) and then not Is_Known_Valid (Entity (L)) then
+ Ltyp := Underlying_Type (Base_Type (Ltyp));
+ end if;
+
+ if Is_Entity_Name (R) and then not Is_Known_Valid (Entity (R)) then
+ Rtyp := Underlying_Type (Base_Type (Rtyp));
+ end if;
+ end if;
+
+ -- Try range analysis on variables and see if ranges are disjoint
+
+ declare
+ LOK, ROK : Boolean;
+ LLo, LHi : Uint;
+ RLo, RHi : Uint;
+
+ begin
+ Determine_Range (L, LOK, LLo, LHi, Assume_Valid);
+ Determine_Range (R, ROK, RLo, RHi, Assume_Valid);
+
+ if LOK and ROK then
+ if LHi < RLo then
+ return LT;
+
+ elsif RHi < LLo then
+ return GT;
+
+ elsif LLo = LHi
+ and then RLo = RHi
+ and then LLo = RLo
+ then
+
+ -- If the range includes a single literal and we can assume
+ -- validity then the result is known even if an operand is
+ -- not static.
+
+ if Assume_Valid then
+ return EQ;
+ else
+ return Unknown;
+ end if;
+
+ elsif LHi = RLo then
+ return LE;
+
+ elsif RHi = LLo then
+ return GE;
+
+ elsif not Is_Known_Valid_Operand (L)
+ and then not Assume_Valid
+ then
+ if Is_Same_Value (L, R) then
+ return EQ;
+ else
+ return Unknown;
+ end if;
+ end if;
+ end if;
+ end;
+
-- Here is where we check for comparisons against maximum bounds of
-- types, where we know that no value can be outside the bounds of
-- the subtype. Note that this routine is allowed to assume that all
-- attempt this optimization with generic types, since the type
-- bounds may not be meaningful in this case.
- -- We are in danger of an infinite recursion here. It does not seem
+ -- We are in danger of an infinite recursion here. It does not seem
-- useful to go more than one level deep, so the parameter Rec is
-- used to protect ourselves against this infinite recursion.
-- See if we can get a decisive check against one operand and
-- a bound of the other operand (four possible tests here).
+ -- Note that we avoid testing junk bounds of a generic type.
+
+ if not Is_Generic_Type (Rtyp) then
+ case Compile_Time_Compare (L, Type_Low_Bound (Rtyp),
+ Discard'Access,
+ Assume_Valid, Rec => True)
+ is
+ when LT => return LT;
+ when LE => return LE;
+ when EQ => return LE;
+ when others => null;
+ end case;
- case Compile_Time_Compare (L, Type_Low_Bound (Rtyp), True) is
- when LT => return LT;
- when LE => return LE;
- when EQ => return LE;
- when others => null;
- end case;
-
- case Compile_Time_Compare (L, Type_High_Bound (Rtyp), True) is
- when GT => return GT;
- when GE => return GE;
- when EQ => return GE;
- when others => null;
- end case;
+ case Compile_Time_Compare (L, Type_High_Bound (Rtyp),
+ Discard'Access,
+ Assume_Valid, Rec => True)
+ is
+ when GT => return GT;
+ when GE => return GE;
+ when EQ => return GE;
+ when others => null;
+ end case;
+ end if;
- case Compile_Time_Compare (Type_Low_Bound (Ltyp), R, True) is
- when GT => return GT;
- when GE => return GE;
- when EQ => return GE;
- when others => null;
- end case;
+ if not Is_Generic_Type (Ltyp) then
+ case Compile_Time_Compare (Type_Low_Bound (Ltyp), R,
+ Discard'Access,
+ Assume_Valid, Rec => True)
+ is
+ when GT => return GT;
+ when GE => return GE;
+ when EQ => return GE;
+ when others => null;
+ end case;
- case Compile_Time_Compare (Type_High_Bound (Ltyp), R, True) is
- when LT => return LT;
- when LE => return LE;
- when EQ => return LE;
- when others => null;
- end case;
+ case Compile_Time_Compare (Type_High_Bound (Ltyp), R,
+ Discard'Access,
+ Assume_Valid, Rec => True)
+ is
+ when LT => return LT;
+ when LE => return LE;
+ when EQ => return LE;
+ when others => null;
+ end case;
+ end if;
end if;
-- Next attempt is to decompose the expressions to extract
return EQ;
elsif Loffs < Roffs then
+ Diff.all := Roffs - Loffs;
return LT;
else
+ Diff.all := Loffs - Roffs;
return GT;
end if;
end if;
if Op = N_Op_Le then
Op := N_Op_Lt;
Opv := Opv + 1;
+
elsif Op = N_Op_Ge then
Op := N_Op_Gt;
Opv := Opv - 1;
Indx := First_Index (T);
while Present (Indx) loop
Typ := Underlying_Type (Etype (Indx));
+
+ -- Never look at junk bounds of a generic type
+
+ if Is_Generic_Type (Typ) then
+ return False;
+ end if;
+
+ -- Otherwise check bounds for compile time known
+
if not Compile_Time_Known_Value (Type_Low_Bound (Typ)) then
return False;
elsif not Compile_Time_Known_Value (Type_High_Bound (Typ)) then
return False;
end if;
- -- If this is not a static expression and we are in configurable run
- -- time mode, then we consider it not known at compile time. This
- -- avoids anomalies where whether something is permitted with a given
- -- configurable run-time library depends on how good the compiler is
- -- at optimizing and knowing that things are constant when they
- -- are non-static.
+ -- If this is not a static expression or a null literal, and we are in
+ -- configurable run-time mode, then we consider it not known at compile
+ -- time. This avoids anomalies where whether something is allowed with a
+ -- given configurable run-time library depends on how good the compiler
+ -- is at optimizing and knowing that things are constant when they are
+ -- nonstatic.
- if Configurable_Run_Time_Mode and then not Is_Static_Expression (Op) then
+ if Configurable_Run_Time_Mode
+ and then K /= N_Null
+ and then not Is_Static_Expression (Op)
+ then
return False;
end if;
Right : constant Node_Id := Right_Opnd (N);
Ltype : constant Entity_Id := Etype (Left);
Rtype : constant Entity_Id := Etype (Right);
+ Otype : Entity_Id := Empty;
Stat : Boolean;
Fold : Boolean;
return;
end if;
+ if Is_Universal_Numeric_Type (Etype (Left))
+ and then
+ Is_Universal_Numeric_Type (Etype (Right))
+ then
+ Otype := Find_Universal_Operator_Type (N);
+ end if;
+
-- Fold for cases where both operands are of integer type
if Is_Integer_Type (Ltype) and then Is_Integer_Type (Rtype) then
Fold_Uint (N, Result, Stat);
end;
- -- Cases where at least one operand is a real. We handle the cases
- -- of both reals, or mixed/real integer cases (the latter happen
- -- only for divide and multiply, and the result is always real).
+ -- Cases where at least one operand is a real. We handle the cases of
+ -- both reals, or mixed/real integer cases (the latter happen only for
+ -- divide and multiply, and the result is always real).
elsif Is_Real_Type (Ltype) or else Is_Real_Type (Rtype) then
declare
Fold_Ureal (N, Result, Stat);
end;
end if;
+
+ -- If the operator was resolved to a specific type, make sure that type
+ -- is frozen even if the expression is folded into a literal (which has
+ -- a universal type).
+
+ if Present (Otype) then
+ Freeze_Before (N, Otype);
+ end if;
end Eval_Arithmetic_Op;
----------------------------
and then Present (Alias (Entity (Name (N))))
and then Is_Enumeration_Type (Base_Type (Typ))
then
- Lit := Alias (Entity (Name (N)));
- while Present (Alias (Lit)) loop
- Lit := Alias (Lit);
- end loop;
+ Lit := Ultimate_Alias (Entity (Name (N)));
if Ekind (Lit) = E_Enumeration_Literal then
if Base_Type (Etype (Lit)) /= Base_Type (Typ) then
end if;
end Eval_Call;
+ --------------------------
+ -- Eval_Case_Expression --
+ --------------------------
+
+ -- Right now we do not attempt folding of any case expressions, and the
+ -- language does not require it, so the only required processing is to
+ -- do the check for all expressions appearing in the case expression.
+
+ procedure Eval_Case_Expression (N : Node_Id) is
+ Alt : Node_Id;
+
+ begin
+ Check_Non_Static_Context (Expression (N));
+
+ Alt := First (Alternatives (N));
+ while Present (Alt) loop
+ Check_Non_Static_Context (Expression (Alt));
+ Next (Alt);
+ end loop;
+ end Eval_Case_Expression;
+
------------------------
-- Eval_Concatenation --
------------------------
- -- Concatenation is a static function, so the result is static if
- -- both operands are static (RM 4.9(7), 4.9(21)).
+ -- Concatenation is a static function, so the result is static if both
+ -- operands are static (RM 4.9(7), 4.9(21)).
procedure Eval_Concatenation (N : Node_Id) is
Left : constant Node_Id := Left_Opnd (N);
Fold : Boolean;
begin
- -- Concatenation is never static in Ada 83, so if Ada 83
- -- check operand non-static context
+ -- Concatenation is never static in Ada 83, so if Ada 83 check operand
+ -- non-static context.
if Ada_Version = Ada_83
and then Comes_From_Source (N)
Test_Expression_Is_Foldable (N, Left, Right, Stat, Fold);
- if Is_Standard_Character_Type (C_Typ)
- and then Fold
- then
- null;
- else
+ if not (Is_Standard_Character_Type (C_Typ) and then Fold) then
Set_Is_Static_Expression (N, False);
return;
end if;
-- Compile time string concatenation
- -- ??? Note that operands that are aggregates can be marked as
- -- static, so we should attempt at a later stage to fold
- -- concatenations with such aggregates.
+ -- ??? Note that operands that are aggregates can be marked as static,
+ -- so we should attempt at a later stage to fold concatenations with
+ -- such aggregates.
declare
Left_Str : constant Node_Id := Get_String_Val (Left);
-- Eval_Conditional_Expression --
---------------------------------
- -- This GNAT internal construct can never be statically folded, so the
- -- only required processing is to do the check for non-static context
- -- for the two expression operands.
+ -- We can fold to a static expression if the condition and both constituent
+ -- expressions are static. Otherwise, the only required processing is to do
+ -- the check for non-static context for the then and else expressions.
procedure Eval_Conditional_Expression (N : Node_Id) is
- Condition : constant Node_Id := First (Expressions (N));
- Then_Expr : constant Node_Id := Next (Condition);
- Else_Expr : constant Node_Id := Next (Then_Expr);
+ Condition : constant Node_Id := First (Expressions (N));
+ Then_Expr : constant Node_Id := Next (Condition);
+ Else_Expr : constant Node_Id := Next (Then_Expr);
+ Result : Node_Id;
+ Non_Result : Node_Id;
+
+ Rstat : constant Boolean :=
+ Is_Static_Expression (Condition)
+ and then
+ Is_Static_Expression (Then_Expr)
+ and then
+ Is_Static_Expression (Else_Expr);
begin
- Check_Non_Static_Context (Then_Expr);
- Check_Non_Static_Context (Else_Expr);
+ -- If any operand is Any_Type, just propagate to result and do not try
+ -- to fold, this prevents cascaded errors.
+
+ if Etype (Condition) = Any_Type or else
+ Etype (Then_Expr) = Any_Type or else
+ Etype (Else_Expr) = Any_Type
+ then
+ Set_Etype (N, Any_Type);
+ Set_Is_Static_Expression (N, False);
+ return;
+
+ -- Static case where we can fold. Note that we don't try to fold cases
+ -- where the condition is known at compile time, but the result is
+ -- non-static. This avoids possible cases of infinite recursion where
+ -- the expander puts in a redundant test and we remove it. Instead we
+ -- deal with these cases in the expander.
+
+ elsif Rstat then
+
+ -- Select result operand
+
+ if Is_True (Expr_Value (Condition)) then
+ Result := Then_Expr;
+ Non_Result := Else_Expr;
+ else
+ Result := Else_Expr;
+ Non_Result := Then_Expr;
+ end if;
+
+ -- Note that it does not matter if the non-result operand raises a
+ -- Constraint_Error, but if the result raises constraint error then
+ -- we replace the node with a raise constraint error. This will
+ -- properly propagate Raises_Constraint_Error since this flag is
+ -- set in Result.
+
+ if Raises_Constraint_Error (Result) then
+ Rewrite_In_Raise_CE (N, Result);
+ Check_Non_Static_Context (Non_Result);
+
+ -- Otherwise the result operand replaces the original node
+
+ else
+ Rewrite (N, Relocate_Node (Result));
+ end if;
+
+ -- Case of condition not known at compile time
+
+ else
+ Check_Non_Static_Context (Condition);
+ Check_Non_Static_Context (Then_Expr);
+ Check_Non_Static_Context (Else_Expr);
+ end if;
+
+ Set_Is_Static_Expression (N, Rstat);
end Eval_Conditional_Expression;
----------------------
Atyp := Designated_Type (Atyp);
end if;
- -- If we have an array type (we should have but perhaps there
- -- are error cases where this is not the case), then see if we
- -- can do a constant evaluation of the array reference.
+ -- If we have an array type (we should have but perhaps there are
+ -- error cases where this is not the case), then see if we can do
+ -- a constant evaluation of the array reference.
- if Is_Array_Type (Atyp) then
+ if Is_Array_Type (Atyp) and then Atyp /= Any_Composite then
if Ekind (Atyp) = E_String_Literal_Subtype then
Lbd := String_Literal_Low_Bound (Atyp);
else
Set_Sloc (N, Loc);
end if;
end if;
+
+ -- We can also constant-fold if the prefix is a string literal.
+ -- This will be useful in an instantiation or an inlining.
+
+ elsif Compile_Time_Known_Value (Sub)
+ and then Nkind (Arr) = N_String_Literal
+ and then Compile_Time_Known_Value (Lbd)
+ and then Expr_Value (Lbd) = 1
+ and then Expr_Value (Sub) <=
+ String_Literal_Length (Etype (Arr))
+ then
+ declare
+ C : constant Char_Code :=
+ Get_String_Char (Strval (Arr),
+ UI_To_Int (Expr_Value (Sub)));
+ begin
+ Set_Character_Literal_Name (C);
+
+ Elm :=
+ Make_Character_Literal (Loc,
+ Chars => Name_Find,
+ Char_Literal_Value => UI_From_CC (C));
+ Set_Etype (Elm, Component_Type (Atyp));
+ Rewrite (N, Duplicate_Subexpr_No_Checks (Elm));
+ Set_Is_Static_Expression (N, False);
+ end;
end if;
end if;
end;
-- Numeric literals are static (RM 4.9(1)), and have already been marked
-- as static by the analyzer. The reason we did it that early is to allow
-- the possibility of turning off the Is_Static_Expression flag after
- -- analysis, but before resolution, when integer literals are generated
- -- in the expander that do not correspond to static expressions.
+ -- analysis, but before resolution, when integer literals are generated in
+ -- the expander that do not correspond to static expressions.
procedure Eval_Integer_Literal (N : Node_Id) is
T : constant Entity_Id := Etype (N);
function In_Any_Integer_Context return Boolean;
- -- If the literal is resolved with a specific type in a context
- -- where the expected type is Any_Integer, there are no range checks
- -- on the literal. By the time the literal is evaluated, it carries
- -- the type imposed by the enclosing expression, and we must recover
- -- the context to determine that Any_Integer is meant.
+ -- If the literal is resolved with a specific type in a context where
+ -- the expected type is Any_Integer, there are no range checks on the
+ -- literal. By the time the literal is evaluated, it carries the type
+ -- imposed by the enclosing expression, and we must recover the context
+ -- to determine that Any_Integer is meant.
----------------------------
- -- To_Any_Integer_Context --
+ -- In_Any_Integer_Context --
----------------------------
function In_Any_Integer_Context return Boolean is
begin
-- Any_Integer also appears in digits specifications for real types,
- -- but those have bounds smaller that those of any integer base
- -- type, so we can safely ignore these cases.
+ -- but those have bounds smaller that those of any integer base type,
+ -- so we can safely ignore these cases.
return K = N_Number_Declaration
or else K = N_Attribute_Reference
begin
-- If the literal appears in a non-expression context, then it is
- -- certainly appearing in a non-static context, so check it. This
- -- is actually a redundant check, since Check_Non_Static_Context
- -- would check it, but it seems worth while avoiding the call.
+ -- certainly appearing in a non-static context, so check it. This is
+ -- actually a redundant check, since Check_Non_Static_Context would
+ -- check it, but it seems worth while avoiding the call.
if Nkind (Parent (N)) not in N_Subexpr
and then not In_Any_Integer_Context
-- Modular integer literals must be in their base range
if Is_Modular_Integer_Type (T)
- and then Is_Out_Of_Range (N, Base_Type (T))
+ and then Is_Out_Of_Range (N, Base_Type (T), Assume_Valid => True)
then
Out_Of_Range (N);
end if;
Right_Int : constant Uint := Expr_Value (Right);
begin
- if Is_Modular_Integer_Type (Etype (N)) then
+ -- VMS includes bitwise operations on signed types
+
+ if Is_Modular_Integer_Type (Etype (N))
+ or else Is_VMS_Operator (Entity (N))
+ then
declare
Left_Bits : Bits (0 .. UI_To_Int (Esize (Etype (N))) - 1);
Right_Bits : Bits (0 .. UI_To_Int (Esize (Etype (N))) - 1);
-- Eval_Membership_Op --
------------------------
- -- A membership test is potentially static if the expression is static,
- -- and the range is a potentially static range, or is a subtype mark
- -- denoting a static subtype (RM 4.9(12)).
+ -- A membership test is potentially static if the expression is static, and
+ -- the range is a potentially static range, or is a subtype mark denoting a
+ -- static subtype (RM 4.9(12)).
procedure Eval_Membership_Op (N : Node_Id) is
Left : constant Node_Id := Left_Opnd (N);
Fold : Boolean;
begin
- -- Ignore if error in either operand, except to make sure that
- -- Any_Type is properly propagated to avoid junk cascaded errors.
+ -- Ignore if error in either operand, except to make sure that Any_Type
+ -- is properly propagated to avoid junk cascaded errors.
- if Etype (Left) = Any_Type
- or else Etype (Right) = Any_Type
- then
+ if Etype (Left) = Any_Type or else Etype (Right) = Any_Type then
Set_Etype (N, Any_Type);
return;
end if;
+ -- Ignore if types involved have predicates
+
+ if Present (Predicate_Function (Etype (Left)))
+ or else
+ Present (Predicate_Function (Etype (Right)))
+ then
+ return;
+ end if;
+
-- Case of right operand is a subtype name
if Is_Entity_Name (Right) then
return;
end if;
- -- For string membership tests we will check the length
- -- further below.
+ -- For string membership tests we will check the length further on
if not Is_String_Type (Def_Id) then
Lo := Type_Low_Bound (Def_Id);
declare
Typlen : constant Uint := String_Type_Len (Etype (Right));
Strlen : constant Uint :=
- UI_From_Int (String_Length (Strval (Get_String_Val (Left))));
+ UI_From_Int
+ (String_Length (Strval (Get_String_Val (Left))));
begin
Result := (Typlen = Strlen);
end;
end if;
- -- Fold the membership test. We know we have a static range and Lo
- -- and Hi are set to the expressions for the end points of this range.
+ -- Fold the membership test. We know we have a static range and Lo and
+ -- Hi are set to the expressions for the end points of this range.
elsif Is_Real_Type (Etype (Right)) then
declare
end if;
Fold_Uint (N, Test (Result), True);
+
Warn_On_Known_Condition (N);
end Eval_Membership_Op;
Result : Uint;
begin
- -- Exponentiation of an integer raises the exception
- -- Constraint_Error for a negative exponent (RM 4.5.6)
+ -- Exponentiation of an integer raises Constraint_Error for a
+ -- negative exponent (RM 4.5.6).
if Right_Int < 0 then
Apply_Compile_Time_Constraint_Error
Typ : constant Entity_Id := Etype (N);
begin
- -- Negation is equivalent to subtracting from the modulus minus
- -- one. For a binary modulus this is equivalent to the ones-
- -- component of the original value. For non-binary modulus this
- -- is an arbitrary but consistent definition.
+ -- Negation is equivalent to subtracting from the modulus minus one.
+ -- For a binary modulus this is equivalent to the ones-complement of
+ -- the original value. For non-binary modulus this is an arbitrary
+ -- but consistent definition.
if Is_Modular_Integer_Type (Typ) then
Fold_Uint (N, Modulus (Typ) - 1 - Rint, Stat);
Hex : Boolean;
begin
- -- Can only fold if target is string or scalar and subtype is static
- -- Also, do not fold if our parent is an allocator (this is because
- -- the qualified expression is really part of the syntactic structure
- -- of an allocator, and we do not want to end up with something that
+ -- Can only fold if target is string or scalar and subtype is static.
+ -- Also, do not fold if our parent is an allocator (this is because the
+ -- qualified expression is really part of the syntactic structure of an
+ -- allocator, and we do not want to end up with something that
-- corresponds to "new 1" where the 1 is the result of folding a
-- qualified expression).
then
Check_Non_Static_Context (Operand);
- -- If operand is known to raise constraint_error, set the
- -- flag on the expression so it does not get optimized away.
+ -- If operand is known to raise constraint_error, set the flag on the
+ -- expression so it does not get optimized away.
if Nkind (Operand) = N_Raise_Constraint_Error then
Set_Raises_Constraint_Error (N);
Set_Is_Static_Expression (N, Stat);
- if Is_Out_Of_Range (N, Etype (N)) then
+ if Is_Out_Of_Range (N, Etype (N), Assume_Valid => True) then
Out_Of_Range (N);
end if;
end Eval_Qualified_Expression;
PK : constant Node_Kind := Nkind (Parent (N));
begin
- -- If the literal appears in a non-expression context
- -- and not as part of a number declaration, then it is
- -- appearing in a non-static context, so check it.
+ -- If the literal appears in a non-expression context and not as part of
+ -- a number declaration, then it is appearing in a non-static context,
+ -- so check it.
if PK not in N_Subexpr and then PK /= N_Number_Declaration then
Check_Non_Static_Context (N);
-- Eval_Relational_Op --
------------------------
- -- Relational operations are static functions, so the result is static
- -- if both operands are static (RM 4.9(7), 4.9(20)).
+ -- Relational operations are static functions, so the result is static if
+ -- both operands are static (RM 4.9(7), 4.9(20)), except that for strings,
+ -- the result is never static, even if the operands are.
procedure Eval_Relational_Op (N : Node_Id) is
Left : constant Node_Id := Left_Opnd (N);
Right : constant Node_Id := Right_Opnd (N);
Typ : constant Entity_Id := Etype (Left);
+ Otype : Entity_Id := Empty;
Result : Boolean;
Stat : Boolean;
Fold : Boolean;
Length_Mismatch : declare
procedure Get_Static_Length (Op : Node_Id; Len : out Uint);
- -- If Op is an expression for a constrained array with a known
- -- at compile time length, then Len is set to this (non-negative
+ -- If Op is an expression for a constrained array with a known at
+ -- compile time length, then Len is set to this (non-negative
-- length). Otherwise Len is set to minus 1.
-----------------------
-- entity name, and the two X's are the same and K1 and K2 are
-- known at compile time, in this case, the length can also be
-- computed at compile time, even though the bounds are not
- -- known. A common case of this is e.g. (X'First..X'First+5).
+ -- known. A common case of this is e.g. (X'First .. X'First+5).
Extract_Length : declare
procedure Decompose_Expr
if Nkind (Expr) = N_Op_Add
and then Compile_Time_Known_Value (Right_Opnd (Expr))
then
- Exp := Left_Opnd (Expr);
+ Exp := Left_Opnd (Expr);
Cons := Expr_Value (Right_Opnd (Expr));
elsif Nkind (Expr) = N_Op_Subtract
and then Compile_Time_Known_Value (Right_Opnd (Expr))
then
- Exp := Left_Opnd (Expr);
+ Exp := Left_Opnd (Expr);
Cons := -Expr_Value (Right_Opnd (Expr));
+ -- If the bound is a constant created to remove side
+ -- effects, recover original expression to see if it has
+ -- one of the recognizable forms.
+
+ elsif Nkind (Expr) = N_Identifier
+ and then not Comes_From_Source (Entity (Expr))
+ and then Ekind (Entity (Expr)) = E_Constant
+ and then
+ Nkind (Parent (Entity (Expr))) = N_Object_Declaration
+ then
+ Exp := Expression (Parent (Entity (Expr)));
+ Decompose_Expr (Exp, Ent, Kind, Cons);
+
+ -- If original expression includes an entity, create a
+ -- reference to it for use below.
+
+ if Present (Ent) then
+ Exp := New_Occurrence_Of (Ent, Sloc (Ent));
+ end if;
+
else
- Exp := Expr;
+ Exp := Expr;
Cons := Uint_0;
end if;
if Nkind (Exp) = N_Attribute_Reference then
if Attribute_Name (Exp) = Name_First then
Kind := 'F';
+
elsif Attribute_Name (Exp) = Name_Last then
Kind := 'L';
+
else
Ent := Empty;
return;
-- Start of processing for Extract_Length
begin
- Decompose_Expr (Type_Low_Bound (T), Ent1, Kind1, Cons1);
- Decompose_Expr (Type_High_Bound (T), Ent2, Kind2, Cons2);
+ Decompose_Expr
+ (Original_Node (Type_Low_Bound (T)), Ent1, Kind1, Cons1);
+ Decompose_Expr
+ (Original_Node (Type_High_Bound (T)), Ent2, Kind2, Cons2);
if Present (Ent1)
and then Kind1 = Kind2
end Length_Mismatch;
end if;
- -- Another special case: comparisons of access types, where one or both
- -- operands are known to be null, so the result can be determined.
+ -- Test for expression being foldable
- if Is_Access_Type (Typ) then
- if Known_Null (Left) then
- if Known_Null (Right) then
- Fold_Uint (N, Test (Nkind (N) = N_Op_Eq), False);
- Warn_On_Known_Condition (N);
- return;
-
- elsif Known_Non_Null (Right) then
- Fold_Uint (N, Test (Nkind (N) = N_Op_Ne), False);
- Warn_On_Known_Condition (N);
- return;
- end if;
-
- elsif Known_Non_Null (Left) then
- if Known_Null (Right) then
- Fold_Uint (N, Test (Nkind (N) = N_Op_Ne), False);
- Warn_On_Known_Condition (N);
- return;
- end if;
- end if;
- end if;
+ Test_Expression_Is_Foldable (N, Left, Right, Stat, Fold);
- -- Can only fold if type is scalar (don't fold string ops)
+ -- Only comparisons of scalars can give static results. In particular,
+ -- comparisons of strings never yield a static result, even if both
+ -- operands are static strings.
if not Is_Scalar_Type (Typ) then
- Check_Non_Static_Context (Left);
- Check_Non_Static_Context (Right);
- return;
+ Stat := False;
+ Set_Is_Static_Expression (N, False);
end if;
- -- If not foldable we are done
-
- Test_Expression_Is_Foldable (N, Left, Right, Stat, Fold);
+ -- For operators on universal numeric types called as functions with
+ -- an explicit scope, determine appropriate specific numeric type, and
+ -- diagnose possible ambiguity.
- if not Fold then
- return;
+ if Is_Universal_Numeric_Type (Etype (Left))
+ and then
+ Is_Universal_Numeric_Type (Etype (Right))
+ then
+ Otype := Find_Universal_Operator_Type (N);
end if;
- -- Integer and Enumeration (discrete) type cases
-
- if Is_Discrete_Type (Typ) then
- declare
- Left_Int : constant Uint := Expr_Value (Left);
- Right_Int : constant Uint := Expr_Value (Right);
-
- begin
- case Nkind (N) is
- when N_Op_Eq => Result := Left_Int = Right_Int;
- when N_Op_Ne => Result := Left_Int /= Right_Int;
- when N_Op_Lt => Result := Left_Int < Right_Int;
- when N_Op_Le => Result := Left_Int <= Right_Int;
- when N_Op_Gt => Result := Left_Int > Right_Int;
- when N_Op_Ge => Result := Left_Int >= Right_Int;
-
- when others =>
- raise Program_Error;
- end case;
-
- Fold_Uint (N, Test (Result), Stat);
- end;
-
- -- Real type case
-
- else
- pragma Assert (Is_Real_Type (Typ));
+ -- For static real type expressions, we cannot use Compile_Time_Compare
+ -- since it worries about run-time results which are not exact.
+ if Stat and then Is_Real_Type (Typ) then
declare
Left_Real : constant Ureal := Expr_Value_R (Left);
Right_Real : constant Ureal := Expr_Value_R (Right);
raise Program_Error;
end case;
- Fold_Uint (N, Test (Result), Stat);
+ Fold_Uint (N, Test (Result), True);
end;
- end if;
- Warn_On_Known_Condition (N);
- end Eval_Relational_Op;
+ -- For all other cases, we use Compile_Time_Compare to do the compare
- ----------------
- -- Eval_Shift --
- ----------------
+ else
+ declare
+ CR : constant Compare_Result :=
+ Compile_Time_Compare (Left, Right, Assume_Valid => False);
- -- Shift operations are intrinsic operations that can never be static,
- -- so the only processing required is to perform the required check for
- -- a non static context for the two operands.
+ begin
+ if CR = Unknown then
+ return;
+ end if;
- -- Actually we could do some compile time evaluation here some time ???
+ case Nkind (N) is
+ when N_Op_Eq =>
+ if CR = EQ then
+ Result := True;
+ elsif CR = NE or else CR = GT or else CR = LT then
+ Result := False;
+ else
+ return;
+ end if;
- procedure Eval_Shift (N : Node_Id) is
- begin
- Check_Non_Static_Context (Left_Opnd (N));
- Check_Non_Static_Context (Right_Opnd (N));
+ when N_Op_Ne =>
+ if CR = NE or else CR = GT or else CR = LT then
+ Result := True;
+ elsif CR = EQ then
+ Result := False;
+ else
+ return;
+ end if;
+
+ when N_Op_Lt =>
+ if CR = LT then
+ Result := True;
+ elsif CR = EQ or else CR = GT or else CR = GE then
+ Result := False;
+ else
+ return;
+ end if;
+
+ when N_Op_Le =>
+ if CR = LT or else CR = EQ or else CR = LE then
+ Result := True;
+ elsif CR = GT then
+ Result := False;
+ else
+ return;
+ end if;
+
+ when N_Op_Gt =>
+ if CR = GT then
+ Result := True;
+ elsif CR = EQ or else CR = LT or else CR = LE then
+ Result := False;
+ else
+ return;
+ end if;
+
+ when N_Op_Ge =>
+ if CR = GT or else CR = EQ or else CR = GE then
+ Result := True;
+ elsif CR = LT then
+ Result := False;
+ else
+ return;
+ end if;
+
+ when others =>
+ raise Program_Error;
+ end case;
+ end;
+
+ Fold_Uint (N, Test (Result), Stat);
+ end if;
+
+ -- For the case of a folded relational operator on a specific numeric
+ -- type, freeze operand type now.
+
+ if Present (Otype) then
+ Freeze_Before (N, Otype);
+ end if;
+
+ Warn_On_Known_Condition (N);
+ end Eval_Relational_Op;
+
+ ----------------
+ -- Eval_Shift --
+ ----------------
+
+ -- Shift operations are intrinsic operations that can never be static, so
+ -- the only processing required is to perform the required check for a non
+ -- static context for the two operands.
+
+ -- Actually we could do some compile time evaluation here some time ???
+
+ procedure Eval_Shift (N : Node_Id) is
+ begin
+ Check_Non_Static_Context (Left_Opnd (N));
+ Check_Non_Static_Context (Right_Opnd (N));
end Eval_Shift;
------------------------
-- Eval_Short_Circuit --
------------------------
- -- A short circuit operation is potentially static if both operands
- -- are potentially static (RM 4.9 (13))
+ -- A short circuit operation is potentially static if both operands are
+ -- potentially static (RM 4.9 (13)).
procedure Eval_Short_Circuit (N : Node_Id) is
Kind : constant Node_Kind := Nkind (N);
Left : constant Node_Id := Left_Opnd (N);
Right : constant Node_Id := Right_Opnd (N);
Left_Int : Uint;
- Rstat : constant Boolean :=
- Is_Static_Expression (Left)
- and then Is_Static_Expression (Right);
+
+ Rstat : constant Boolean :=
+ Is_Static_Expression (Left)
+ and then
+ Is_Static_Expression (Right);
begin
-- Short circuit operations are never static in Ada 83
- if Ada_Version = Ada_83
- and then Comes_From_Source (N)
- then
+ if Ada_Version = Ada_83 and then Comes_From_Source (N) then
Check_Non_Static_Context (Left);
Check_Non_Static_Context (Right);
return;
-- are a special case, they can still be foldable, even if the right
-- operand raises constraint error.
- -- If either operand is Any_Type, just propagate to result and
- -- do not try to fold, this prevents cascaded errors.
+ -- If either operand is Any_Type, just propagate to result and do not
+ -- try to fold, this prevents cascaded errors.
if Etype (Left) = Any_Type or else Etype (Right) = Any_Type then
Set_Etype (N, Any_Type);
Left_Int := Expr_Value (Left);
if (Kind = N_And_Then and then Is_False (Left_Int))
- or else (Kind = N_Or_Else and Is_True (Left_Int))
+ or else
+ (Kind = N_Or_Else and then Is_True (Left_Int))
then
Fold_Uint (N, Left_Int, Rstat);
return;
-- Eval_Slice --
----------------
- -- Slices can never be static, so the only processing required is to
- -- check for non-static context if an explicit range is given.
+ -- Slices can never be static, so the only processing required is to check
+ -- for non-static context if an explicit range is given.
procedure Eval_Slice (N : Node_Id) is
Drange : constant Node_Id := Discrete_Range (N);
Check_Non_Static_Context (Low_Bound (Drange));
Check_Non_Static_Context (High_Bound (Drange));
end if;
+
+ -- A slice of the form A (subtype), when the subtype is the index of
+ -- the type of A, is redundant, the slice can be replaced with A, and
+ -- this is worth a warning.
+
+ if Is_Entity_Name (Prefix (N)) then
+ declare
+ E : constant Entity_Id := Entity (Prefix (N));
+ T : constant Entity_Id := Etype (E);
+ begin
+ if Ekind (E) = E_Constant
+ and then Is_Array_Type (T)
+ and then Is_Entity_Name (Drange)
+ then
+ if Is_Entity_Name (Original_Node (First_Index (T)))
+ and then Entity (Original_Node (First_Index (T)))
+ = Entity (Drange)
+ then
+ if Warn_On_Redundant_Constructs then
+ Error_Msg_N ("redundant slice denotes whole array?", N);
+ end if;
+
+ -- The following might be a useful optimization????
+
+ -- Rewrite (N, New_Occurrence_Of (E, Sloc (N)));
+ end if;
+ end if;
+ end;
+ end if;
end Eval_Slice;
-------------------------
begin
-- Nothing to do if error type (handles cases like default expressions
- -- or generics where we have not yet fully resolved the type)
+ -- or generics where we have not yet fully resolved the type).
if Bas = Any_Type or else Bas = Any_String then
return;
end if;
-- Here if Etype of string literal is normal Etype (not yet possible,
- -- but may be possible in future!)
+ -- but may be possible in future).
elsif not Is_OK_Static_Expression
(Type_Low_Bound (Etype (First_Index (Typ))))
return;
end if;
- -- Test for illegal Ada 95 cases. A string literal is illegal in
- -- Ada 95 if its bounds are outside the index base type and this
- -- index type is static. This can happen in only two ways. Either
- -- the string literal is too long, or it is null, and the lower
- -- bound is type'First. In either case it is the upper bound that
- -- is out of range of the index type.
+ -- Test for illegal Ada 95 cases. A string literal is illegal in Ada 95
+ -- if its bounds are outside the index base type and this index type is
+ -- static. This can happen in only two ways. Either the string literal
+ -- is too long, or it is null, and the lower bound is type'First. In
+ -- either case it is the upper bound that is out of range of the index
+ -- type.
if Ada_Version >= Ada_95 then
if Root_Type (Bas) = Standard_String
-- A type conversion is potentially static if its subtype mark is for a
-- static scalar subtype, and its operand expression is potentially static
- -- (RM 4.9 (10))
+ -- (RM 4.9(10)).
procedure Eval_Type_Conversion (N : Node_Id) is
Operand : constant Node_Id := Expression (N);
Fold : Boolean;
function To_Be_Treated_As_Integer (T : Entity_Id) return Boolean;
- -- Returns true if type T is an integer type, or if it is a
- -- fixed-point type to be treated as an integer (i.e. the flag
- -- Conversion_OK is set on the conversion node).
+ -- Returns true if type T is an integer type, or if it is a fixed-point
+ -- type to be treated as an integer (i.e. the flag Conversion_OK is set
+ -- on the conversion node).
function To_Be_Treated_As_Real (T : Entity_Id) return Boolean;
-- Returns true if type T is a floating-point type, or if it is a
Fold_Uint (N, Expr_Value (Operand), Stat);
end if;
- if Is_Out_Of_Range (N, Etype (N)) then
+ if Is_Out_Of_Range (N, Etype (N), Assume_Valid => True) then
Out_Of_Range (N);
end if;
-------------------
-- Predefined unary operators are static functions (RM 4.9(20)) and thus
- -- are potentially static if the operand is potentially static (RM 4.9(7))
+ -- are potentially static if the operand is potentially static (RM 4.9(7)).
procedure Eval_Unary_Op (N : Node_Id) is
Right : constant Node_Id := Right_Opnd (N);
+ Otype : Entity_Id := Empty;
Stat : Boolean;
Fold : Boolean;
return;
end if;
+ if Etype (Right) = Universal_Integer
+ or else
+ Etype (Right) = Universal_Real
+ then
+ Otype := Find_Universal_Operator_Type (N);
+ end if;
+
-- Fold for integer case
if Is_Integer_Type (Etype (N)) then
Fold_Ureal (N, Result, Stat);
end;
end if;
+
+ -- If the operator was resolved to a specific type, make sure that type
+ -- is frozen even if the expression is folded into a literal (which has
+ -- a universal type).
+
+ if Present (Otype) then
+ Freeze_Before (N, Otype);
+ end if;
end Eval_Unary_Op;
-------------------------------
if Is_Entity_Name (N) then
Ent := Entity (N);
- -- An enumeration literal that was either in the source or
- -- created as a result of static evaluation.
+ -- An enumeration literal that was either in the source or created
+ -- as a result of static evaluation.
if Ekind (Ent) = E_Enumeration_Literal then
return Enumeration_Rep (Ent);
return Expr_Rep_Value (Constant_Value (Ent));
end if;
- -- An integer literal that was either in the source or created
- -- as a result of static evaluation.
+ -- An integer literal that was either in the source or created as a
+ -- result of static evaluation.
elsif Kind = N_Integer_Literal then
return Intval (N);
pragma Assert (Kind = N_Character_Literal);
Ent := Entity (N);
- -- Since Character literals of type Standard.Character don't
- -- have any defining character literals built for them, they
- -- do not have their Entity set, so just use their Char
- -- code. Otherwise for user-defined character literals use
- -- their Pos value as usual which is the same as the Rep value.
+ -- Since Character literals of type Standard.Character don't have any
+ -- defining character literals built for them, they do not have their
+ -- Entity set, so just use their Char code. Otherwise for user-
+ -- defined character literals use their Pos value as usual which is
+ -- the same as the Rep value.
if No (Ent) then
return Char_Literal_Value (N);
if Is_Entity_Name (N) then
Ent := Entity (N);
- -- An enumeration literal that was either in the source or
- -- created as a result of static evaluation.
+ -- An enumeration literal that was either in the source or created as
+ -- a result of static evaluation.
if Ekind (Ent) = E_Enumeration_Literal then
Val := Enumeration_Pos (Ent);
Val := Expr_Value (Constant_Value (Ent));
end if;
- -- An integer literal that was either in the source or created
- -- as a result of static evaluation.
+ -- An integer literal that was either in the source or created as a
+ -- result of static evaluation.
elsif Kind = N_Integer_Literal then
Val := Intval (N);
return Ureal_0;
end if;
- -- If we fall through, we have a node that cannot be interpreted
- -- as a compile time constant. That is definitely an error.
+ -- If we fall through, we have a node that cannot be interpreted as a
+ -- compile time constant. That is definitely an error.
raise Program_Error;
end Expr_Value_R;
end if;
end Expr_Value_S;
+ ----------------------------------
+ -- Find_Universal_Operator_Type --
+ ----------------------------------
+
+ function Find_Universal_Operator_Type (N : Node_Id) return Entity_Id is
+ PN : constant Node_Id := Parent (N);
+ Call : constant Node_Id := Original_Node (N);
+ Is_Int : constant Boolean := Is_Integer_Type (Etype (N));
+
+ Is_Fix : constant Boolean :=
+ Nkind (N) in N_Binary_Op
+ and then Nkind (Right_Opnd (N)) /= Nkind (Left_Opnd (N));
+ -- A mixed-mode operation in this context indicates the presence of
+ -- fixed-point type in the designated package.
+
+ Is_Relational : constant Boolean := Etype (N) = Standard_Boolean;
+ -- Case where N is a relational (or membership) operator (else it is an
+ -- arithmetic one).
+
+ In_Membership : constant Boolean :=
+ Nkind (PN) in N_Membership_Test
+ and then
+ Nkind (Right_Opnd (PN)) = N_Range
+ and then
+ Is_Universal_Numeric_Type (Etype (Left_Opnd (PN)))
+ and then
+ Is_Universal_Numeric_Type
+ (Etype (Low_Bound (Right_Opnd (PN))))
+ and then
+ Is_Universal_Numeric_Type
+ (Etype (High_Bound (Right_Opnd (PN))));
+ -- Case where N is part of a membership test with a universal range
+
+ E : Entity_Id;
+ Pack : Entity_Id;
+ Typ1 : Entity_Id := Empty;
+ Priv_E : Entity_Id;
+
+ function Is_Mixed_Mode_Operand (Op : Node_Id) return Boolean;
+ -- Check whether one operand is a mixed-mode operation that requires the
+ -- presence of a fixed-point type. Given that all operands are universal
+ -- and have been constant-folded, retrieve the original function call.
+
+ ---------------------------
+ -- Is_Mixed_Mode_Operand --
+ ---------------------------
+
+ function Is_Mixed_Mode_Operand (Op : Node_Id) return Boolean is
+ Onod : constant Node_Id := Original_Node (Op);
+ begin
+ return Nkind (Onod) = N_Function_Call
+ and then Present (Next_Actual (First_Actual (Onod)))
+ and then Etype (First_Actual (Onod)) /=
+ Etype (Next_Actual (First_Actual (Onod)));
+ end Is_Mixed_Mode_Operand;
+
+ -- Start of processing for Find_Universal_Operator_Type
+
+ begin
+ if Nkind (Call) /= N_Function_Call
+ or else Nkind (Name (Call)) /= N_Expanded_Name
+ then
+ return Empty;
+
+ -- There are several cases where the context does not imply the type of
+ -- the operands:
+ -- - the universal expression appears in a type conversion;
+ -- - the expression is a relational operator applied to universal
+ -- operands;
+ -- - the expression is a membership test with a universal operand
+ -- and a range with universal bounds.
+
+ elsif Nkind (Parent (N)) = N_Type_Conversion
+ or else Is_Relational
+ or else In_Membership
+ then
+ Pack := Entity (Prefix (Name (Call)));
+
+ -- If the prefix is a package declared elsewhere, iterate over its
+ -- visible entities, otherwise iterate over all declarations in the
+ -- designated scope.
+
+ if Ekind (Pack) = E_Package
+ and then not In_Open_Scopes (Pack)
+ then
+ Priv_E := First_Private_Entity (Pack);
+ else
+ Priv_E := Empty;
+ end if;
+
+ Typ1 := Empty;
+ E := First_Entity (Pack);
+ while Present (E) and then E /= Priv_E loop
+ if Is_Numeric_Type (E)
+ and then Nkind (Parent (E)) /= N_Subtype_Declaration
+ and then Comes_From_Source (E)
+ and then Is_Integer_Type (E) = Is_Int
+ and then
+ (Nkind (N) in N_Unary_Op
+ or else Is_Relational
+ or else Is_Fixed_Point_Type (E) = Is_Fix)
+ then
+ if No (Typ1) then
+ Typ1 := E;
+
+ -- Before emitting an error, check for the presence of a
+ -- mixed-mode operation that specifies a fixed point type.
+
+ elsif Is_Relational
+ and then
+ (Is_Mixed_Mode_Operand (Left_Opnd (N))
+ or else Is_Mixed_Mode_Operand (Right_Opnd (N)))
+ and then Is_Fixed_Point_Type (E) /= Is_Fixed_Point_Type (Typ1)
+
+ then
+ if Is_Fixed_Point_Type (E) then
+ Typ1 := E;
+ end if;
+
+ else
+ -- More than one type of the proper class declared in P
+
+ Error_Msg_N ("ambiguous operation", N);
+ Error_Msg_Sloc := Sloc (Typ1);
+ Error_Msg_N ("\possible interpretation (inherited)#", N);
+ Error_Msg_Sloc := Sloc (E);
+ Error_Msg_N ("\possible interpretation (inherited)#", N);
+ return Empty;
+ end if;
+ end if;
+
+ Next_Entity (E);
+ end loop;
+ end if;
+
+ return Typ1;
+ end Find_Universal_Operator_Type;
+
--------------------------
-- Flag_Non_Static_Expr --
--------------------------
Ent : Entity_Id;
begin
- -- If we are folding a named number, retain the entity in the
- -- literal, for ASIS use.
+ -- If we are folding a named number, retain the entity in the literal,
+ -- for ASIS use.
if Is_Entity_Name (N)
and then Ekind (Entity (N)) = E_Named_Integer
-- For a result of type integer, substitute an N_Integer_Literal node
-- for the result of the compile time evaluation of the expression.
+ -- For ASIS use, set a link to the original named number when not in
+ -- a generic context.
if Is_Integer_Type (Typ) then
Rewrite (N, Make_Integer_Literal (Loc, Val));
+
Set_Original_Entity (N, Ent);
-- Otherwise we have an enumeration type, and we substitute either
Ent : Entity_Id;
begin
- -- If we are folding a named number, retain the entity in the
- -- literal, for ASIS use.
+ -- If we are folding a named number, retain the entity in the literal,
+ -- for ASIS use.
if Is_Entity_Name (N)
and then Ekind (Entity (N)) = E_Named_Real
end if;
Rewrite (N, Make_Real_Literal (Loc, Realval => Val));
+
+ -- Set link to original named number, for ASIS use
+
Set_Original_Entity (N, Ent);
-- Both the actual and expected type comes from the original expression
elsif not Is_Scalar_Type (T1) or else not Is_Scalar_Type (T1) then
return False;
+ -- If T1 has infinities but T2 doesn't have infinities, then T1 is
+ -- definitely not compatible with T2.
+
+ elsif Is_Floating_Point_Type (T1)
+ and then Has_Infinities (T1)
+ and then Is_Floating_Point_Type (T2)
+ and then not Has_Infinities (T2)
+ then
+ return False;
+
else
L1 := Type_Low_Bound (T1);
H1 := Type_High_Bound (T1);
-- Check bounds to see if comparison possible at compile time
- if Compile_Time_Compare (L1, L2) in Compare_GE
+ if Compile_Time_Compare (L1, L2, Assume_Valid => True) in Compare_GE
and then
- Compile_Time_Compare (H1, H2) in Compare_LE
+ Compile_Time_Compare (H1, H2, Assume_Valid => True) in Compare_LE
then
return True;
end if;
-----------------
function Is_In_Range
- (N : Node_Id;
- Typ : Entity_Id;
- Fixed_Int : Boolean := False;
- Int_Real : Boolean := False) return Boolean
+ (N : Node_Id;
+ Typ : Entity_Id;
+ Assume_Valid : Boolean := False;
+ Fixed_Int : Boolean := False;
+ Int_Real : Boolean := False) return Boolean
is
- Val : Uint;
- Valr : Ureal;
-
begin
- -- Universal types have no range limits, so always in range
-
- if Typ = Universal_Integer or else Typ = Universal_Real then
- return True;
-
- -- Never in range if not scalar type. Don't know if this can
- -- actually happen, but our spec allows it, so we must check!
-
- elsif not Is_Scalar_Type (Typ) then
- return False;
-
- -- Never in range unless we have a compile time known value
-
- elsif not Compile_Time_Known_Value (N) then
- return False;
-
- else
- declare
- Lo : constant Node_Id := Type_Low_Bound (Typ);
- Hi : constant Node_Id := Type_High_Bound (Typ);
- LB_Known : constant Boolean := Compile_Time_Known_Value (Lo);
- UB_Known : constant Boolean := Compile_Time_Known_Value (Hi);
-
- begin
- -- Fixed point types should be considered as such only in
- -- flag Fixed_Int is set to False.
-
- if Is_Floating_Point_Type (Typ)
- or else (Is_Fixed_Point_Type (Typ) and then not Fixed_Int)
- or else Int_Real
- then
- Valr := Expr_Value_R (N);
-
- if LB_Known and then Valr >= Expr_Value_R (Lo)
- and then UB_Known and then Valr <= Expr_Value_R (Hi)
- then
- return True;
- else
- return False;
- end if;
-
- else
- Val := Expr_Value (N);
-
- if LB_Known and then Val >= Expr_Value (Lo)
- and then UB_Known and then Val <= Expr_Value (Hi)
- then
- return True;
- else
- return False;
- end if;
- end if;
- end;
- end if;
+ return Test_In_Range (N, Typ, Assume_Valid, Fixed_Int, Int_Real)
+ = In_Range;
end Is_In_Range;
-------------------
-- Is_OK_Static_Subtype --
--------------------------
- -- Determines if Typ is a static subtype as defined in (RM 4.9(26))
- -- where neither bound raises constraint error when evaluated.
+ -- Determines if Typ is a static subtype as defined in (RM 4.9(26)) where
+ -- neither bound raises constraint error when evaluated.
function Is_OK_Static_Subtype (Typ : Entity_Id) return Boolean is
Base_T : constant Entity_Id := Base_Type (Typ);
return True;
else
- -- Scalar_Range (Typ) might be an N_Subtype_Indication, so
- -- use Get_Type_Low,High_Bound.
+ -- Scalar_Range (Typ) might be an N_Subtype_Indication, so use
+ -- Get_Type_{Low,High}_Bound.
return Is_OK_Static_Subtype (Anc_Subt)
and then Is_OK_Static_Expression (Type_Low_Bound (Typ))
---------------------
function Is_Out_Of_Range
- (N : Node_Id;
- Typ : Entity_Id;
- Fixed_Int : Boolean := False;
- Int_Real : Boolean := False) return Boolean
+ (N : Node_Id;
+ Typ : Entity_Id;
+ Assume_Valid : Boolean := False;
+ Fixed_Int : Boolean := False;
+ Int_Real : Boolean := False) return Boolean
is
- Val : Uint;
- Valr : Ureal;
-
begin
- -- Universal types have no range limits, so always in range
-
- if Typ = Universal_Integer or else Typ = Universal_Real then
- return False;
-
- -- Never out of range if not scalar type. Don't know if this can
- -- actually happen, but our spec allows it, so we must check!
-
- elsif not Is_Scalar_Type (Typ) then
- return False;
-
- -- Never out of range if this is a generic type, since the bounds
- -- of generic types are junk. Note that if we only checked for
- -- static expressions (instead of compile time known values) below,
- -- we would not need this check, because values of a generic type
- -- can never be static, but they can be known at compile time.
-
- elsif Is_Generic_Type (Typ) then
- return False;
-
- -- Never out of range unless we have a compile time known value
-
- elsif not Compile_Time_Known_Value (N) then
- return False;
-
- else
- declare
- Lo : constant Node_Id := Type_Low_Bound (Typ);
- Hi : constant Node_Id := Type_High_Bound (Typ);
- LB_Known : constant Boolean := Compile_Time_Known_Value (Lo);
- UB_Known : constant Boolean := Compile_Time_Known_Value (Hi);
-
- begin
- -- Real types (note that fixed-point types are not treated
- -- as being of a real type if the flag Fixed_Int is set,
- -- since in that case they are regarded as integer types).
-
- if Is_Floating_Point_Type (Typ)
- or else (Is_Fixed_Point_Type (Typ) and then not Fixed_Int)
- or else Int_Real
- then
- Valr := Expr_Value_R (N);
-
- if LB_Known and then Valr < Expr_Value_R (Lo) then
- return True;
-
- elsif UB_Known and then Expr_Value_R (Hi) < Valr then
- return True;
-
- else
- return False;
- end if;
-
- else
- Val := Expr_Value (N);
-
- if LB_Known and then Val < Expr_Value (Lo) then
- return True;
-
- elsif UB_Known and then Expr_Value (Hi) < Val then
- return True;
-
- else
- return False;
- end if;
- end if;
- end;
- end if;
+ return Test_In_Range (N, Typ, Assume_Valid, Fixed_Int, Int_Real)
+ = Out_Of_Range;
end Is_Out_Of_Range;
---------------------
begin
-- If we have the static expression case, then this is an illegality
-- in Ada 95 mode, except that in an instance, we never generate an
- -- error (if the error is legitimate, it was already diagnosed in
- -- the template). The expression to compute the length of a packed
- -- array is attached to the array type itself, and deserves a separate
- -- message.
+ -- error (if the error is legitimate, it was already diagnosed in the
+ -- template). The expression to compute the length of a packed array is
+ -- attached to the array type itself, and deserves a separate message.
if Is_Static_Expression (N)
and then not In_Instance
(N, "value not in range of}", CE_Range_Check_Failed);
end if;
- -- Here we generate a warning for the Ada 83 case, or when we are
- -- in an instance, or when we have a non-static expression case.
+ -- Here we generate a warning for the Ada 83 case, or when we are in an
+ -- instance, or when we have a non-static expression case.
else
Apply_Compile_Time_Constraint_Error
Typ : constant Entity_Id := Etype (N);
begin
- -- If we want to raise CE in the condition of a raise_CE node
- -- we may as well get rid of the condition
+ -- If we want to raise CE in the condition of a N_Raise_CE node
+ -- we may as well get rid of the condition.
if Present (Parent (N))
and then Nkind (Parent (N)) = N_Raise_Constraint_Error
then
Set_Condition (Parent (N), Empty);
- -- If the expression raising CE is a N_Raise_CE node, we can use
- -- that one. We just preserve the type of the context
+ -- If the expression raising CE is a N_Raise_CE node, we can use that
+ -- one. We just preserve the type of the context.
elsif Nkind (Exp) = N_Raise_Constraint_Error then
Rewrite (N, Exp);
Set_Etype (N, Typ);
- -- We have to build an explicit raise_ce node
+ -- Else build an explcit N_Raise_CE
else
Rewrite (N,
T2 : Entity_Id) return Boolean
is
begin
+ -- Scalar types
+
if Is_Scalar_Type (T1) then
-- Definitely compatible if we match
then
return True;
- -- Base types must match, but we don't check that (should
- -- we???) but we do at least check that both types are
- -- real, or both types are not real.
+ -- Base types must match, but we don't check that (should we???) but
+ -- we do at least check that both types are real, or both types are
+ -- not real.
elsif Is_Real_Type (T1) /= Is_Real_Type (T2) then
return False;
end;
end if;
+ -- Access types
+
elsif Is_Access_Type (T1) then
- return not Is_Constrained (T2)
- or else Subtypes_Statically_Match
- (Designated_Type (T1), Designated_Type (T2));
+ return (not Is_Constrained (T2)
+ or else (Subtypes_Statically_Match
+ (Designated_Type (T1), Designated_Type (T2))))
+ and then not (Can_Never_Be_Null (T2)
+ and then not Can_Never_Be_Null (T1));
+
+ -- All other cases
else
return (Is_Composite_Type (T1) and then not Is_Constrained (T2))
-- subtype, i.e. both types must be constrained or unconstrained.
-- To understand the requirement for this test, see RM 4.9.1(1).
- -- As is made clear in RM 3.5.4(11), type Integer, for example
- -- is a constrained subtype with constraint bounds matching the
- -- bounds of its corresponding unconstrained base type. In this
- -- situation, Integer and Integer'Base do not statically match,
- -- even though they have the same bounds.
+ -- As is made clear in RM 3.5.4(11), type Integer, for example is
+ -- a constrained subtype with constraint bounds matching the bounds
+ -- of its corresponding unconstrained base type. In this situation,
+ -- Integer and Integer'Base do not statically match, even though
+ -- they have the same bounds.
- -- We only apply this test to types in Standard and types that
- -- appear in user programs. That way, we do not have to be
- -- too careful about setting Is_Constrained right for itypes.
+ -- We only apply this test to types in Standard and types that appear
+ -- in user programs. That way, we do not have to be too careful about
+ -- setting Is_Constrained right for Itypes.
if Is_Numeric_Type (T1)
and then (Is_Constrained (T1) /= Is_Constrained (T2))
then
return False;
- -- A generic scalar type does not statically match its base
- -- type (AI-311). In this case we make sure that the formals,
- -- which are first subtypes of their bases, are constrained.
+ -- A generic scalar type does not statically match its base type
+ -- (AI-311). In this case we make sure that the formals, which are
+ -- first subtypes of their bases, are constrained.
elsif Is_Generic_Type (T1)
and then Is_Generic_Type (T2)
return False;
end if;
- -- If there was an error in either range, then just assume
- -- the types statically match to avoid further junk errors
+ -- If there was an error in either range, then just assume the types
+ -- statically match to avoid further junk errors.
- if Error_Posted (Scalar_Range (T1))
- or else
- Error_Posted (Scalar_Range (T2))
+ if No (Scalar_Range (T1)) or else No (Scalar_Range (T2))
+ or else Error_Posted (Scalar_Range (T1))
+ or else Error_Posted (Scalar_Range (T2))
then
return True;
end if;
then
return False;
- -- If either type has constraint error bounds, then say
- -- that they match to avoid junk cascaded errors here.
+ -- If either type has constraint error bounds, then say that
+ -- they match to avoid junk cascaded errors here.
elsif not Is_OK_Static_Subtype (T1)
or else not Is_OK_Static_Subtype (T2)
return True;
- -- A definite type does not match an indefinite or classwide type
+ -- A definite type does not match an indefinite or classwide type.
-- However, a generic type with unknown discriminants may be
-- instantiated with a type with no discriminants, and conformance
- -- checking on an inherited operation may compare the actual with
- -- the subtype that renames it in the instance.
+ -- checking on an inherited operation may compare the actual with the
+ -- subtype that renames it in the instance.
elsif
Has_Unknown_Discriminants (T1) /= Has_Unknown_Discriminants (T2)
elsif Is_Array_Type (T1) then
- -- If either subtype is unconstrained then both must be,
- -- and if both are unconstrained then no further checking
- -- is needed.
+ -- If either subtype is unconstrained then both must be, and if both
+ -- are unconstrained then no further checking is needed.
if not Is_Constrained (T1) or else not Is_Constrained (T2) then
return not (Is_Constrained (T1) or else Is_Constrained (T2));
end if;
- -- Both subtypes are constrained, so check that the index
- -- subtypes statically match.
+ -- Both subtypes are constrained, so check that the index subtypes
+ -- statically match.
declare
Index1 : Node_Id := First_Index (T1);
if Can_Never_Be_Null (T1) /= Can_Never_Be_Null (T2) then
return False;
- elsif Ekind (T1) = E_Access_Subprogram_Type
- or else Ekind (T1) = E_Anonymous_Access_Subprogram_Type
+ elsif Ekind_In (T1, E_Access_Subprogram_Type,
+ E_Anonymous_Access_Subprogram_Type)
then
return
Subtype_Conformant
Set_Etype (N, Any_Type);
return;
- -- If left operand raises constraint error, then replace node N with
- -- the raise constraint error node, and we are obviously not foldable.
+ -- If left operand raises constraint error, then replace node N with the
+ -- Raise_Constraint_Error node, and we are obviously not foldable.
-- Is_Static_Expression is set from the two operands in the normal way,
-- and we check the right operand if it is in a non-static context.
Set_Is_Static_Expression (N, Rstat);
return;
- -- Similar processing for the case of the right operand. Note that
- -- we don't use this routine for the short-circuit case, so we do
- -- not have to worry about that special case here.
+ -- Similar processing for the case of the right operand. Note that we
+ -- don't use this routine for the short-circuit case, so we do not have
+ -- to worry about that special case here.
elsif Raises_Constraint_Error (Op2) then
if not Rstat then
return;
-- If result is not static, then check non-static contexts on operands
- -- since one of them may be static and the other one may not be static
+ -- since one of them may be static and the other one may not be static.
elsif not Rstat then
Check_Non_Static_Context (Op1);
and then Compile_Time_Known_Value (Op2);
return;
- -- Else result is static and foldable. Both operands are static,
- -- and neither raises constraint error, so we can definitely fold.
+ -- Else result is static and foldable. Both operands are static, and
+ -- neither raises constraint error, so we can definitely fold.
else
Set_Is_Static_Expression (N);
end if;
end Test_Expression_Is_Foldable;
+ -------------------
+ -- Test_In_Range --
+ -------------------
+
+ function Test_In_Range
+ (N : Node_Id;
+ Typ : Entity_Id;
+ Assume_Valid : Boolean;
+ Fixed_Int : Boolean;
+ Int_Real : Boolean) return Range_Membership
+ is
+ Val : Uint;
+ Valr : Ureal;
+
+ pragma Warnings (Off, Assume_Valid);
+ -- For now Assume_Valid is unreferenced since the current implementation
+ -- always returns Unknown if N is not a compile time known value, but we
+ -- keep the parameter to allow for future enhancements in which we try
+ -- to get the information in the variable case as well.
+
+ begin
+ -- Universal types have no range limits, so always in range
+
+ if Typ = Universal_Integer or else Typ = Universal_Real then
+ return In_Range;
+
+ -- Never known if not scalar type. Don't know if this can actually
+ -- happen, but our spec allows it, so we must check!
+
+ elsif not Is_Scalar_Type (Typ) then
+ return Unknown;
+
+ -- Never known if this is a generic type, since the bounds of generic
+ -- types are junk. Note that if we only checked for static expressions
+ -- (instead of compile time known values) below, we would not need this
+ -- check, because values of a generic type can never be static, but they
+ -- can be known at compile time.
+
+ elsif Is_Generic_Type (Typ) then
+ return Unknown;
+
+ -- Never known unless we have a compile time known value
+
+ elsif not Compile_Time_Known_Value (N) then
+ return Unknown;
+
+ -- General processing with a known compile time value
+
+ else
+ declare
+ Lo : Node_Id;
+ Hi : Node_Id;
+
+ LB_Known : Boolean;
+ HB_Known : Boolean;
+
+ begin
+ Lo := Type_Low_Bound (Typ);
+ Hi := Type_High_Bound (Typ);
+
+ LB_Known := Compile_Time_Known_Value (Lo);
+ HB_Known := Compile_Time_Known_Value (Hi);
+
+ -- Fixed point types should be considered as such only if flag
+ -- Fixed_Int is set to False.
+
+ if Is_Floating_Point_Type (Typ)
+ or else (Is_Fixed_Point_Type (Typ) and then not Fixed_Int)
+ or else Int_Real
+ then
+ Valr := Expr_Value_R (N);
+
+ if LB_Known and HB_Known then
+ if Valr >= Expr_Value_R (Lo)
+ and then
+ Valr <= Expr_Value_R (Hi)
+ then
+ return In_Range;
+ else
+ return Out_Of_Range;
+ end if;
+
+ elsif (LB_Known and then Valr < Expr_Value_R (Lo))
+ or else
+ (HB_Known and then Valr > Expr_Value_R (Hi))
+ then
+ return Out_Of_Range;
+
+ else
+ return Unknown;
+ end if;
+
+ else
+ Val := Expr_Value (N);
+
+ if LB_Known and HB_Known then
+ if Val >= Expr_Value (Lo)
+ and then
+ Val <= Expr_Value (Hi)
+ then
+ return In_Range;
+ else
+ return Out_Of_Range;
+ end if;
+
+ elsif (LB_Known and then Val < Expr_Value (Lo))
+ or else
+ (HB_Known and then Val > Expr_Value (Hi))
+ then
+ return Out_Of_Range;
+
+ else
+ return Unknown;
+ end if;
+ end if;
+ end;
+ end if;
+ end Test_In_Range;
+
--------------
-- To_Bits --
--------------
E : Entity_Id;
procedure Why_Not_Static_List (L : List_Id);
- -- A version that can be called on a list of expressions. Finds
- -- all non-static violations in any element of the list.
+ -- A version that can be called on a list of expressions. Finds all
+ -- non-static violations in any element of the list.
-------------------------
-- Why_Not_Static_List --
-- Start of processing for Why_Not_Static
begin
- -- If in ACATS mode (debug flag 2), then suppress all these
- -- messages, this avoids massive updates to the ACATS base line.
+ -- If in ACATS mode (debug flag 2), then suppress all these messages,
+ -- this avoids massive updates to the ACATS base line.
if Debug_Flag_2 then
return;
"(RM 4.9(5))!", N, E);
end if;
- when N_Binary_Op | N_And_Then | N_Or_Else | N_Membership_Test =>
+ when N_Binary_Op | N_Short_Circuit | N_Membership_Test =>
if Nkind (N) in N_Op_Shift then
Error_Msg_N
("shift functions are never static (RM 4.9(6,18))!", N);
if Attribute_Name (N) = Name_Size then
Error_Msg_N
- ("size attribute is only static for scalar type " &
+ ("size attribute is only static for static scalar type " &
"(RM 4.9(7,8))", N);
-- Flag array cases
return;
- -- Special case generic types, since again this is a common
- -- source of confusion.
+ -- Special case generic types, since again this is a common source
+ -- of confusion.
elsif Is_Generic_Actual_Type (E)
or else
when N_Type_Conversion =>
Why_Not_Static (Expression (N));
- if not Is_Scalar_Type (Etype (Prefix (N)))
- or else not Is_Static_Subtype (Etype (Prefix (N)))
+ if not Is_Scalar_Type (Entity (Subtype_Mark (N)))
+ or else not Is_Static_Subtype (Entity (Subtype_Mark (N)))
then
Error_Msg_N
("static conversion requires static scalar subtype result " &
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