----------------------
+------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- --
-- B o d y --
-- --
--- $Revision$
--- --
--- Copyright (C) 1992-2002 Free Software Foundation, Inc. --
+-- Copyright (C) 1992-2009, Free Software Foundation, Inc. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
--- ware Foundation; either version 2, or (at your option) any later ver- --
+-- ware Foundation; either version 3, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
-- for more details. You should have received a copy of the GNU General --
--- Public License distributed with GNAT; see file COPYING. If not, write --
--- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
--- MA 02111-1307, USA. --
+-- Public License distributed with GNAT; see file COPYING3. If not, go to --
+-- http://www.gnu.org/licenses for a complete copy of the license. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
--- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
+-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
with Elists; use Elists;
with Errout; use Errout;
with Eval_Fat; use Eval_Fat;
+with Exp_Util; use Exp_Util;
+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;
with Sem_Res; use Sem_Res;
with Sem_Util; use Sem_Util;
-----------------------------------------
-- The compile time evaluation of expressions is distributed over several
- -- Eval_xxx procedures. These procedures are called immediatedly after
+ -- Eval_xxx procedures. These procedures are called immediately after
-- a subexpression is resolved and is therefore accomplished in a bottom
-- up fashion. The flags are synthesized using the following approach.
-- Local Subprograms --
-----------------------
- function Constant_Array_Ref (Op : Node_Id) return Node_Id;
- -- The caller has checked that Op is an array reference (i.e. that its
- -- node kind is N_Indexed_Component). If the array reference is constant
- -- at compile time, and yields a constant value of a discrete type, then
- -- the expression node for the constant value is returned. otherwise Empty
- -- is returned. This is used by Compile_Time_Known_Value, as well as by
- -- Expr_Value and Expr_Rep_Value.
-
function From_Bits (B : Bits; T : Entity_Id) return Uint;
-- Converts a bit string of length B'Length to a Uint value to be used
-- for a target of type T, which is a modular type. This procedure
-- 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 comaprison, 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;
------------------------------
procedure Check_Non_Static_Context (N : Node_Id) is
- T : Entity_Id := Etype (N);
- Checks_On : constant Boolean :=
+ T : constant Entity_Id := Etype (N);
+ Checks_On : constant Boolean :=
not Index_Checks_Suppressed (T)
and not Range_Checks_Suppressed (T);
begin
- -- We need the check only for static expressions not raising CE
- -- We can also ignore cases in which the type is Any_Type
+ -- Ignore cases of non-scalar types or error types
- if not Is_OK_Static_Expression (N)
- or else Etype (N) = Any_Type
- then
+ if T = Any_Type or else not Is_Scalar_Type (T) then
return;
+ end if;
- -- Skip this check for non-scalar expressions
+ -- At this stage we have a scalar type. If we have an expression
+ -- that raises CE, then we already issued a warning or error msg
+ -- so there is nothing more to be done in this routine.
+
+ if Raises_Constraint_Error (N) then
+ return;
+ end if;
+
+ -- Now we have a scalar type which is not marked as raising a
+ -- constraint error exception. The main purpose of this routine
+ -- is to deal with static expressions appearing in a non-static
+ -- context. That means that if we do not have a static expression
+ -- then there is not much to do. The one case that we deal with
+ -- here is that if we have a floating-point value that is out of
+ -- range, then we post a warning that an infinity will result.
+
+ if not Is_Static_Expression (N) then
+ if Is_Floating_Point_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);
+ end if;
- elsif not Is_Scalar_Type (T) then
return;
end if;
-- 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;
(N, Corresponding_Integer_Value (N) * Small_Value (T));
elsif not UR_Is_Zero (Realval (N)) then
- declare
- RT : constant Entity_Id := Base_Type (T);
- X : constant Ureal := Machine (RT, Realval (N), Round);
- begin
- -- Warn if result of static rounding actually differs from
- -- runtime evaluation, which uses round to even.
+ -- Note: even though RM 4.9(38) specifies biased rounding,
+ -- this has been modified by AI-100 in order to prevent
+ -- confusing differences in rounding between static and
+ -- non-static expressions. AI-100 specifies that the effect
+ -- of such rounding is implementation dependent, and in GNAT
+ -- we round to nearest even to match the run-time behavior.
- if Warn_On_Biased_Rounding and Rounding_Was_Biased then
- Error_Msg_N ("static expression does not round to even"
- & " ('R'M 4.9(38))?", N);
- end if;
-
- Set_Realval (N, X);
- end;
+ Set_Realval
+ (N, Machine (Base_Type (T), Realval (N), Round_Even, N));
end if;
Set_Is_Machine_Number (N);
-- 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);
-- Compile_Time_Compare --
--------------------------
- function Compile_Time_Compare (L, R : Node_Id) return Compare_Result is
- Ltyp : constant Entity_Id := Etype (L);
- Rtyp : constant Entity_Id := Etype (R);
+ function Compile_Time_Compare
+ (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 : 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 --
-------------------
Lf : constant Node_Id := Compare_Fixup (L);
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 one case is where
+ -- one subscript is missing and the other is explicitly set to 1).
+
+ -----------------------
+ -- Is_Same_Subscript --
+ -----------------------
+
+ function Is_Same_Subscript (L, R : List_Id) return Boolean is
+ begin
+ if L = No_List then
+ if R = No_List then
+ return True;
+ else
+ return Expr_Value (First (R)) = Uint_1;
+ end if;
+
+ else
+ if R = No_List then
+ return Expr_Value (First (L)) = Uint_1;
+ else
+ return Expr_Value (First (L)) = Expr_Value (First (R));
+ end if;
+ end if;
+ end 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)
+ -- 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 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_Constant or else
- Ekind (Entity (Lf)) = E_In_Parameter or else
- Ekind (Entity (Lf)) = E_Loop_Parameter)
+ and then Present (Entity (Lf))
+ and then not Is_Floating_Point_Type (Etype (L))
+ 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;
+
+ -- 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
+ -- 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
+ -- 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 discrete types
+
+ if not Is_Discrete_Type (Ltyp)
+ or else not Is_Discrete_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.
- if Is_Discrete_Type (Ltyp)
- and then not Is_Generic_Type (Ltyp)
- and then not Is_Generic_Type (Rtyp)
- then
- if Is_Same_Value (R, Type_High_Bound (Ltyp)) then
- return LE;
-
- elsif Is_Same_Value (R, Type_Low_Bound (Ltyp)) then
- return GE;
-
- elsif Is_Same_Value (L, Type_High_Bound (Rtyp)) then
- return GE;
+ -- 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.
+
+ if not Rec then
+
+ -- 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_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;
- elsif Is_Same_Value (L, Type_Low_Bound (Ltyp)) then
- return LE;
+ 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,
+ 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;
return EQ;
elsif Loffs < Roffs then
+ Diff.all := Roffs - Loffs;
return LT;
else
+ Diff.all := Loffs - Roffs;
return GT;
end if;
+ end if;
+ end;
+
+ -- Next attempt is to see if we have an entity compared with a
+ -- compile time known value, where there is a current value
+ -- conditional for the entity which can tell us the result.
+
+ declare
+ Var : Node_Id;
+ -- Entity variable (left operand)
+
+ Val : Uint;
+ -- Value (right operand)
+
+ Inv : Boolean;
+ -- If False, we have reversed the operands
+
+ Op : Node_Kind;
+ -- Comparison operator kind from Get_Current_Value_Condition call
+
+ Opn : Node_Id;
+ -- Value from Get_Current_Value_Condition call
+
+ Opv : Uint;
+ -- Value of Opn
+
+ Result : Compare_Result;
+ -- Known result before inversion
+
+ begin
+ if Is_Entity_Name (L)
+ and then Compile_Time_Known_Value (R)
+ then
+ Var := L;
+ Val := Expr_Value (R);
+ Inv := False;
+
+ elsif Is_Entity_Name (R)
+ and then Compile_Time_Known_Value (L)
+ then
+ Var := R;
+ Val := Expr_Value (L);
+ Inv := True;
- -- If the expressions are different, we cannot say at compile
- -- time how they compare, so we return the Unknown indication.
+ -- That was the last chance at finding a compile time result
else
return Unknown;
end if;
+
+ Get_Current_Value_Condition (Var, Op, Opn);
+
+ -- That was the last chance, so if we got nothing return
+
+ if No (Opn) then
+ return Unknown;
+ end if;
+
+ Opv := Expr_Value (Opn);
+
+ -- We got a comparison, so we might have something interesting
+
+ -- Convert LE to LT and GE to GT, just so we have fewer cases
+
+ 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;
+ end if;
+
+ -- Deal with equality case
+
+ if Op = N_Op_Eq then
+ if Val = Opv then
+ Result := EQ;
+ elsif Opv < Val then
+ Result := LT;
+ else
+ Result := GT;
+ end if;
+
+ -- Deal with inequality case
+
+ elsif Op = N_Op_Ne then
+ if Val = Opv then
+ Result := NE;
+ else
+ return Unknown;
+ end if;
+
+ -- Deal with greater than case
+
+ elsif Op = N_Op_Gt then
+ if Opv >= Val then
+ Result := GT;
+ elsif Opv = Val - 1 then
+ Result := GE;
+ else
+ return Unknown;
+ end if;
+
+ -- Deal with less than case
+
+ else pragma Assert (Op = N_Op_Lt);
+ if Opv <= Val then
+ Result := LT;
+ elsif Opv = Val + 1 then
+ Result := LE;
+ else
+ return Unknown;
+ end if;
+ end if;
+
+ -- Deal with inverting result
+
+ if Inv then
+ case Result is
+ when GT => return LT;
+ when GE => return LE;
+ when LT => return GT;
+ when LE => return GE;
+ when others => return Result;
+ end case;
+ end if;
+
+ return Result;
end;
end if;
end Compile_Time_Compare;
+ -------------------------------
+ -- Compile_Time_Known_Bounds --
+ -------------------------------
+
+ function Compile_Time_Known_Bounds (T : Entity_Id) return Boolean is
+ Indx : Node_Id;
+ Typ : Entity_Id;
+
+ begin
+ if not Is_Array_Type (T) then
+ return False;
+ end if;
+
+ 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;
+ else
+ Next_Index (Indx);
+ end if;
+ end loop;
+
+ return True;
+ end Compile_Time_Known_Bounds;
+
------------------------------
-- Compile_Time_Known_Value --
------------------------------
function Compile_Time_Known_Value (Op : Node_Id) return Boolean is
K : constant Node_Kind := Nkind (Op);
CV_Ent : CV_Entry renames CV_Cache (Nat (Op) mod CV_Cache_Size);
- Val : Node_Id;
begin
-- Never known at compile time if bad type or raises constraint error
return False;
end if;
+ -- 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 K /= N_Null
+ and then not Is_Static_Expression (Op)
+ then
+ return False;
+ end if;
+
-- If we have an entity name, then see if it is the name of a constant
-- and if so, test the corresponding constant value, or the name of
-- an enumeration literal, which is always a constant.
elsif K = N_Attribute_Reference then
return Attribute_Name (Op) = Name_Null_Parameter;
-
- -- A reference to an element of a constant array may be constant.
-
- elsif K = N_Indexed_Component then
- Val := Constant_Array_Ref (Op);
-
- if Present (Val) then
- CV_Ent.N := Op;
- CV_Ent.V := Expr_Value (Val);
- return True;
- end if;
end if;
end if;
end if;
end Compile_Time_Known_Value_Or_Aggr;
- ------------------------
- -- Constant_Array_Ref --
- ------------------------
-
- function Constant_Array_Ref (Op : Node_Id) return Node_Id is
- begin
- if List_Length (Expressions (Op)) = 1
- and then Is_Entity_Name (Prefix (Op))
- and then Ekind (Entity (Prefix (Op))) = E_Constant
- then
- declare
- Arr : constant Node_Id := Constant_Value (Entity (Prefix (Op)));
- Sub : constant Node_Id := First (Expressions (Op));
- Ind : constant Node_Id := First_Index (Etype (Arr));
- Lbd : constant Node_Id := Type_Low_Bound (Etype (Ind));
-
- Lin : Nat;
- -- Linear one's origin subscript value for array reference
-
- Elm : Node_Id;
- -- Value from constant array
-
- begin
- if Compile_Time_Known_Value (Sub)
- and then Nkind (Arr) = N_Aggregate
- and then Compile_Time_Known_Value (Lbd)
- and then Is_Discrete_Type (Component_Type (Etype (Arr)))
- then
- Lin := UI_To_Int (Expr_Value (Sub) - Expr_Value (Lbd)) + 1;
-
- if List_Length (Expressions (Arr)) >= Lin then
- Elm := Pick (Expressions (Arr), Lin);
-
- if Compile_Time_Known_Value (Elm) then
- return Elm;
- end if;
- end if;
- end if;
- end;
- end if;
-
- return Empty;
- end Constant_Array_Ref;
-
-----------------
-- Eval_Actual --
-----------------
if Right_Int = 0 then
Apply_Compile_Time_Constraint_Error
- (N, "division by zero", CE_Divide_By_Zero);
+ (N, "division by zero",
+ CE_Divide_By_Zero,
+ Warn => not Stat);
return;
+
else
Result := Left_Int / Right_Int;
end if;
if Right_Int = 0 then
Apply_Compile_Time_Constraint_Error
- (N, "mod with zero divisor", CE_Divide_By_Zero);
+ (N, "mod with zero divisor",
+ CE_Divide_By_Zero,
+ Warn => not Stat);
return;
else
Result := Left_Int mod Right_Int;
if Right_Int = 0 then
Apply_Compile_Time_Constraint_Error
- (N, "rem with zero divisor", CE_Divide_By_Zero);
+ (N, "rem with zero divisor",
+ CE_Divide_By_Zero,
+ Warn => not Stat);
return;
+
else
Result := Left_Int rem Right_Int;
end if;
if Is_Modular_Integer_Type (Ltype) then
Result := Result mod Modulus (Ltype);
+
+ -- For a signed integer type, check non-static overflow
+
+ elsif (not Stat) and then Is_Signed_Integer_Type (Ltype) then
+ declare
+ BT : constant Entity_Id := Base_Type (Ltype);
+ Lo : constant Uint := Expr_Value (Type_Low_Bound (BT));
+ Hi : constant Uint := Expr_Value (Type_High_Bound (BT));
+ begin
+ if Result < Lo or else Result > Hi then
+ Apply_Compile_Time_Constraint_Error
+ (N, "value not in range of }?",
+ CE_Overflow_Check_Failed,
+ Ent => BT);
+ return;
+ end if;
+ end;
end if;
- Fold_Uint (N, Result);
+ -- If we get here we can fold the result
+
+ Fold_Uint (N, Result, Stat);
end;
-- Cases where at least one operand is a real. We handle the cases
Result := Left_Real / Right_Real;
end if;
- Fold_Ureal (N, Result);
+ Fold_Ureal (N, Result, Stat);
end;
end if;
-
- Set_Is_Static_Expression (N, Stat);
-
end Eval_Arithmetic_Op;
----------------------------
procedure Eval_Character_Literal (N : Node_Id) is
pragma Warnings (Off, N);
-
begin
null;
end Eval_Character_Literal;
+ ---------------
+ -- Eval_Call --
+ ---------------
+
+ -- Static function calls are either calls to predefined operators
+ -- with static arguments, or calls to functions that rename a literal.
+ -- Only the latter case is handled here, predefined operators are
+ -- constant-folded elsewhere.
+
+ -- If the function is itself inherited (see 7423-001) the literal of
+ -- the parent type must be explicitly converted to the return type
+ -- of the function.
+
+ procedure Eval_Call (N : Node_Id) is
+ Loc : constant Source_Ptr := Sloc (N);
+ Typ : constant Entity_Id := Etype (N);
+ Lit : Entity_Id;
+
+ begin
+ if Nkind (N) = N_Function_Call
+ and then No (Parameter_Associations (N))
+ and then Is_Entity_Name (Name (N))
+ 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;
+
+ if Ekind (Lit) = E_Enumeration_Literal then
+ if Base_Type (Etype (Lit)) /= Base_Type (Typ) then
+ Rewrite
+ (N, Convert_To (Typ, New_Occurrence_Of (Lit, Loc)));
+ else
+ Rewrite (N, New_Occurrence_Of (Lit, Loc));
+ end if;
+
+ Resolve (N, Typ);
+ end if;
+ end if;
+ end Eval_Call;
+
------------------------
-- 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_83
+ if Ada_Version = Ada_83
and then Comes_From_Source (N)
then
Check_Non_Static_Context (Left);
Test_Expression_Is_Foldable (N, Left, Right, Stat, Fold);
- if (C_Typ = Standard_Character
- or else C_Typ = Standard_Wide_Character)
- 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.
+ -- 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);
- Left_Len : Nat;
- Right_Str : constant Node_Id := Get_String_Val (Right);
+ Left_Str : constant Node_Id := Get_String_Val (Left);
+ Left_Len : Nat;
+ Right_Str : constant Node_Id := Get_String_Val (Right);
+ Folded_Val : String_Id;
begin
-- Establish new string literal, and store left operand. We make
if Nkind (Left_Str) = N_String_Literal then
Left_Len := String_Length (Strval (Left_Str));
- Start_String (Strval (Left_Str));
+
+ -- If the left operand is the empty string, and the right operand
+ -- is a string literal (the case of "" & "..."), the result is the
+ -- value of the right operand. This optimization is important when
+ -- Is_Folded_In_Parser, to avoid copying an enormous right
+ -- operand.
+
+ if Left_Len = 0 and then Nkind (Right_Str) = N_String_Literal then
+ Folded_Val := Strval (Right_Str);
+ else
+ Start_String (Strval (Left_Str));
+ end if;
+
else
Start_String;
- Store_String_Char (Char_Literal_Value (Left_Str));
+ Store_String_Char (UI_To_CC (Char_Literal_Value (Left_Str)));
Left_Len := 1;
end if;
- -- Now append the characters of the right operand
+ -- Now append the characters of the right operand, unless we
+ -- optimized the "" & "..." case above.
if Nkind (Right_Str) = N_String_Literal then
- declare
- S : constant String_Id := Strval (Right_Str);
-
- begin
- for J in 1 .. String_Length (S) loop
- Store_String_Char (Get_String_Char (S, J));
- end loop;
- end;
+ if Left_Len /= 0 then
+ Store_String_Chars (Strval (Right_Str));
+ Folded_Val := End_String;
+ end if;
else
- Store_String_Char (Char_Literal_Value (Right_Str));
+ Store_String_Char (UI_To_CC (Char_Literal_Value (Right_Str)));
+ Folded_Val := End_String;
end if;
Set_Is_Static_Expression (N, Stat);
Set_Etype (N, Etype (Right));
end if;
- Fold_Str (N, End_String);
+ Fold_Str (N, Folded_Val, Static => True);
end if;
end;
end Eval_Concatenation;
end if;
end if;
- -- Fall through if the name is not static.
+ -- Fall through if the name is not static
Validate_Static_Object_Name (N);
end Eval_Entity_Name;
-- Eval_Indexed_Component --
----------------------------
- -- Indexed components are never static, so the only required processing
- -- is to perform the check for non-static context on the index values.
+ -- Indexed components are never static, so we need to perform the check
+ -- for non-static context on the index values. Then, we check if the
+ -- value can be obtained at compile time, even though it is non-static.
procedure Eval_Indexed_Component (N : Node_Id) is
Expr : Node_Id;
begin
+ -- Check for non-static context on index values
+
Expr := First (Expressions (N));
while Present (Expr) loop
Check_Non_Static_Context (Expr);
Next (Expr);
end loop;
+ -- If the indexed component appears in an object renaming declaration
+ -- then we do not want to try to evaluate it, since in this case we
+ -- need the identity of the array element.
+
+ if Nkind (Parent (N)) = N_Object_Renaming_Declaration then
+ return;
+
+ -- Similarly if the indexed component appears as the prefix of an
+ -- attribute we don't want to evaluate it, because at least for
+ -- some cases of attributes we need the identify (e.g. Access, Size)
+
+ elsif Nkind (Parent (N)) = N_Attribute_Reference then
+ return;
+ end if;
+
+ -- Note: there are other cases, such as the left side of an assignment,
+ -- or an OUT parameter for a call, where the replacement results in the
+ -- illegal use of a constant, But these cases are illegal in the first
+ -- place, so the replacement, though silly, is harmless.
+
+ -- Now see if this is a constant array reference
+
+ if List_Length (Expressions (N)) = 1
+ and then Is_Entity_Name (Prefix (N))
+ and then Ekind (Entity (Prefix (N))) = E_Constant
+ and then Present (Constant_Value (Entity (Prefix (N))))
+ then
+ declare
+ Loc : constant Source_Ptr := Sloc (N);
+ Arr : constant Node_Id := Constant_Value (Entity (Prefix (N)));
+ Sub : constant Node_Id := First (Expressions (N));
+
+ Atyp : Entity_Id;
+ -- Type of array
+
+ Lin : Nat;
+ -- Linear one's origin subscript value for array reference
+
+ Lbd : Node_Id;
+ -- Lower bound of the first array index
+
+ Elm : Node_Id;
+ -- Value from constant array
+
+ begin
+ Atyp := Etype (Arr);
+
+ if Is_Access_Type (Atyp) then
+ 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 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
+ Lbd := Type_Low_Bound (Etype (First_Index (Atyp)));
+ end if;
+
+ if Compile_Time_Known_Value (Sub)
+ and then Nkind (Arr) = N_Aggregate
+ and then Compile_Time_Known_Value (Lbd)
+ and then Is_Discrete_Type (Component_Type (Atyp))
+ then
+ Lin := UI_To_Int (Expr_Value (Sub) - Expr_Value (Lbd)) + 1;
+
+ if List_Length (Expressions (Arr)) >= Lin then
+ Elm := Pick (Expressions (Arr), Lin);
+
+ -- If the resulting expression is compile time known,
+ -- then we can rewrite the indexed component with this
+ -- value, being sure to mark the result as non-static.
+ -- We also reset the Sloc, in case this generates an
+ -- error later on (e.g. 136'Access).
+
+ if Compile_Time_Known_Value (Elm) then
+ Rewrite (N, Duplicate_Subexpr_No_Checks (Elm));
+ Set_Is_Static_Expression (N, False);
+ 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;
+ end if;
end Eval_Indexed_Component;
--------------------------
-- 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.
+
+ ----------------------------
+ -- In_Any_Integer_Context --
+ ----------------------------
+
+ function In_Any_Integer_Context return Boolean is
+ Par : constant Node_Id := Parent (N);
+ K : constant Node_Kind := Nkind (Par);
+
+ 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.
+
+ return K = N_Number_Declaration
+ or else K = N_Attribute_Reference
+ or else K = N_Attribute_Definition_Clause
+ or else K = N_Modular_Type_Definition
+ or else K = N_Signed_Integer_Type_Definition;
+ end In_Any_Integer_Context;
+
+ -- Start of processing for Eval_Integer_Literal
+
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 then
+ if Nkind (Parent (N)) not in N_Subexpr
+ and then not In_Any_Integer_Context
+ then
Check_Non_Static_Context (N);
end if;
-- 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;
end loop;
end if;
- Fold_Uint (N, From_Bits (Left_Bits, Etype (N)));
+ Fold_Uint (N, From_Bits (Left_Bits, Etype (N)), Stat);
end;
else
if Nkind (N) = N_Op_And then
Fold_Uint (N,
- Test (Is_True (Left_Int) and then Is_True (Right_Int)));
+ Test (Is_True (Left_Int) and then Is_True (Right_Int)), Stat);
elsif Nkind (N) = N_Op_Or then
Fold_Uint (N,
- Test (Is_True (Left_Int) or else Is_True (Right_Int)));
+ Test (Is_True (Left_Int) or else Is_True (Right_Int)), Stat);
else
pragma Assert (Nkind (N) = N_Op_Xor);
Fold_Uint (N,
- Test (Is_True (Left_Int) xor Is_True (Right_Int)));
+ Test (Is_True (Left_Int) xor Is_True (Right_Int)), Stat);
end if;
end if;
-
- Set_Is_Static_Expression (N, Stat);
end;
end Eval_Logical_Op;
-- 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
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);
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
Result := not Result;
end if;
- Fold_Uint (N, Test (Result));
+ Fold_Uint (N, Test (Result), True);
Warn_On_Known_Condition (N);
-
end Eval_Membership_Op;
------------------------
procedure Eval_Named_Integer (N : Node_Id) is
begin
Fold_Uint (N,
- Expr_Value (Expression (Declaration_Node (Entity (N)))));
+ Expr_Value (Expression (Declaration_Node (Entity (N)))), True);
end Eval_Named_Integer;
---------------------
procedure Eval_Named_Real (N : Node_Id) is
begin
Fold_Ureal (N,
- Expr_Value_R (Expression (Declaration_Node (Entity (N)))));
+ Expr_Value_R (Expression (Declaration_Node (Entity (N)))), True);
end Eval_Named_Real;
-------------------
if Right_Int < 0 then
Apply_Compile_Time_Constraint_Error
- (N, "integer exponent negative", CE_Range_Check_Failed);
+ (N, "integer exponent negative",
+ CE_Range_Check_Failed,
+ Warn => not Stat);
return;
else
Result := Result mod Modulus (Etype (N));
end if;
- Fold_Uint (N, Result);
+ Fold_Uint (N, Result, Stat);
end if;
end;
if Right_Int < 0 then
Apply_Compile_Time_Constraint_Error
- (N, "zero ** negative integer", CE_Range_Check_Failed);
+ (N, "zero ** negative integer",
+ CE_Range_Check_Failed,
+ Warn => not Stat);
return;
else
- Fold_Ureal (N, Ureal_0);
+ Fold_Ureal (N, Ureal_0, Stat);
end if;
else
- Fold_Ureal (N, Left_Real ** Right_Int);
+ Fold_Ureal (N, Left_Real ** Right_Int, Stat);
end if;
end;
end if;
-
- Set_Is_Static_Expression (N, Stat);
end;
end Eval_Op_Expon;
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);
+ Fold_Uint (N, Modulus (Typ) - 1 - Rint, Stat);
else
pragma Assert (Is_Boolean_Type (Typ));
- Fold_Uint (N, Test (not Is_True (Rint)));
+ Fold_Uint (N, Test (not Is_True (Rint)), Stat);
end if;
Set_Is_Static_Expression (N, Stat);
Hex : Boolean;
begin
- -- Can only fold if target is string or scalar and subtype is static
+ -- 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
or else Nkind (Parent (N)) = N_Allocator
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 Nkind (Operand) = N_Raise_Constraint_Error then
+ Set_Raises_Constraint_Error (N);
+ end if;
+
return;
end if;
-- Fold the result of qualification
if Is_Discrete_Type (Target_Type) then
- Fold_Uint (N, Expr_Value (Operand));
- Set_Is_Static_Expression (N, Stat);
+ Fold_Uint (N, Expr_Value (Operand), Stat);
-- Preserve Print_In_Hex indication
end if;
elsif Is_Real_Type (Target_Type) then
- Fold_Ureal (N, Expr_Value_R (Operand));
- Set_Is_Static_Expression (N, Stat);
+ Fold_Ureal (N, Expr_Value_R (Operand), Stat);
else
- Fold_Str (N, Strval (Get_String_Val (Operand)));
+ Fold_Str (N, Strval (Get_String_Val (Operand)), Stat);
if not Stat then
Set_Is_Static_Expression (N, False);
return;
end if;
- if Is_Out_Of_Range (N, Etype (N)) then
+ -- The expression may be foldable but not static
+
+ Set_Is_Static_Expression (N, Stat);
+
+ if Is_Out_Of_Range (N, Etype (N), Assume_Valid => True) then
Out_Of_Range (N);
end if;
-
end Eval_Qualified_Expression;
-----------------------
-- in the expander that do not correspond to static expressions.
procedure Eval_Real_Literal (N : Node_Id) is
+ PK : constant Node_Kind := Nkind (Parent (N));
+
begin
- -- If the literal appears in a non-expression context, then it is
- -- certainly 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 Nkind (Parent (N)) not in N_Subexpr then
+ if PK not in N_Subexpr and then PK /= N_Number_Declaration then
Check_Non_Static_Context (N);
end if;
-
end Eval_Real_Literal;
------------------------
------------------------
-- Relational operations are static functions, so the result is static
- -- if both operands are static (RM 4.9(7), 4.9(20)).
+ -- 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);
Fold : Boolean;
begin
- -- One special case to deal with first. If we can tell that
- -- the result will be false because the lengths of one or
- -- more index subtypes are compile time known and different,
- -- then we can replace the entire result by False. We only
- -- do this for one dimensional arrays, because the case of
- -- multi-dimensional arrays is rare and too much trouble!
+ -- One special case to deal with first. If we can tell that the result
+ -- will be false because the lengths of one or more index subtypes are
+ -- compile time known and different, then we can replace the entire
+ -- result by False. We only do this for one dimensional arrays, because
+ -- the case of multi-dimensional arrays is rare and too much trouble! If
+ -- one of the operands is an illegal aggregate, its type might still be
+ -- an arbitrary composite type, so nothing to do.
if Is_Array_Type (Typ)
+ and then Typ /= Any_Composite
and then Number_Dimensions (Typ) = 1
- and then (Nkind (N) = N_Op_Eq
- or else Nkind (N) = N_Op_Ne)
+ and then (Nkind (N) = N_Op_Eq or else Nkind (N) = N_Op_Ne)
then
if Raises_Constraint_Error (Left)
or else Raises_Constraint_Error (Right)
return;
end if;
- declare
+ -- OK, we have the case where we may be able to do this fold
+
+ 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 length). Otherwise Len is set to minus 1.
+ -- 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.
+
+ -----------------------
+ -- Get_Static_Length --
+ -----------------------
procedure Get_Static_Length (Op : Node_Id; Len : out Uint) is
T : Entity_Id;
begin
+ -- First easy case string literal
+
if Nkind (Op) = N_String_Literal then
Len := UI_From_Int (String_Length (Strval (Op)));
+ return;
+ end if;
+
+ -- Second easy case, not constrained subtype, so no length
- elsif not Is_Constrained (Etype (Op)) then
+ if not Is_Constrained (Etype (Op)) then
Len := Uint_Minus_1;
+ return;
+ end if;
- else
- T := Etype (First_Index (Etype (Op)));
+ -- General case
- if Is_Discrete_Type (T)
- and then
- Compile_Time_Known_Value (Type_Low_Bound (T))
- and then
- Compile_Time_Known_Value (Type_High_Bound (T))
+ T := Etype (First_Index (Etype (Op)));
+
+ -- The simple case, both bounds are known at compile time
+
+ if Is_Discrete_Type (T)
+ and then
+ Compile_Time_Known_Value (Type_Low_Bound (T))
+ and then
+ Compile_Time_Known_Value (Type_High_Bound (T))
+ then
+ Len := UI_Max (Uint_0,
+ Expr_Value (Type_High_Bound (T)) -
+ Expr_Value (Type_Low_Bound (T)) + 1);
+ return;
+ end if;
+
+ -- A more complex case, where the bounds are of the form
+ -- X [+/- K1] .. X [+/- K2]), where X is an expression that is
+ -- either A'First or A'Last (with A an entity name), or X is an
+ -- 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).
+
+ Extract_Length : declare
+ procedure Decompose_Expr
+ (Expr : Node_Id;
+ Ent : out Entity_Id;
+ Kind : out Character;
+ Cons : out Uint);
+ -- Given an expression, see if is of the form above,
+ -- X [+/- K]. If so Ent is set to the entity in X,
+ -- Kind is 'F','L','E' for 'First/'Last/simple entity,
+ -- and Cons is the value of K. If the expression is
+ -- not of the required form, Ent is set to Empty.
+
+ --------------------
+ -- Decompose_Expr --
+ --------------------
+
+ procedure Decompose_Expr
+ (Expr : Node_Id;
+ Ent : out Entity_Id;
+ Kind : out Character;
+ Cons : out Uint)
+ is
+ Exp : Node_Id;
+
+ begin
+ if Nkind (Expr) = N_Op_Add
+ and then Compile_Time_Known_Value (Right_Opnd (Expr))
+ then
+ 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);
+ Cons := -Expr_Value (Right_Opnd (Expr));
+
+ else
+ Exp := Expr;
+ Cons := Uint_0;
+ end if;
+
+ -- At this stage Exp is set to the potential X
+
+ 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;
+ end if;
+
+ Exp := Prefix (Exp);
+
+ else
+ Kind := 'E';
+ end if;
+
+ if Is_Entity_Name (Exp)
+ and then Present (Entity (Exp))
+ then
+ Ent := Entity (Exp);
+ else
+ Ent := Empty;
+ end if;
+ end Decompose_Expr;
+
+ -- Local Variables
+
+ Ent1, Ent2 : Entity_Id;
+ Kind1, Kind2 : Character;
+ Cons1, Cons2 : Uint;
+
+ -- Start of processing for Extract_Length
+
+ begin
+ 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
+ and then Ent1 = Ent2
then
- Len := UI_Max (Uint_0,
- Expr_Value (Type_High_Bound (T)) -
- Expr_Value (Type_Low_Bound (T)) + 1);
+ Len := Cons2 - Cons1 + 1;
else
Len := Uint_Minus_1;
end if;
- end if;
+ end Extract_Length;
end Get_Static_Length;
+ -- Local Variables
+
Len_L : Uint;
Len_R : Uint;
+ -- Start of processing for Length_Mismatch
+
begin
Get_Static_Length (Left, Len_L);
Get_Static_Length (Right, Len_R);
and then Len_R /= Uint_Minus_1
and then Len_L /= Len_R
then
- Fold_Uint (N, Test (Nkind (N) = N_Op_Ne));
- Set_Is_Static_Expression (N, False);
+ Fold_Uint (N, Test (Nkind (N) = N_Op_Ne), False);
Warn_On_Known_Condition (N);
return;
end if;
- end;
+ end Length_Mismatch;
end if;
- -- Can only fold if type is scalar (don't fold string ops)
-
- if not Is_Scalar_Type (Typ) then
- Check_Non_Static_Context (Left);
- Check_Non_Static_Context (Right);
- return;
- end if;
-
- -- If not foldable we are done
+ -- Test for expression being foldable
Test_Expression_Is_Foldable (N, Left, Right, Stat, Fold);
- if not Fold then
- return;
+ -- 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
+ Stat := False;
+ Set_Is_Static_Expression (N, False);
end if;
- -- Integer and Enumeration (discrete) type cases
+ -- For static real type expressions, we cannot use Compile_Time_Compare
+ -- since it worries about run-time results which are not exact.
- if Is_Discrete_Type (Typ) then
+ if Stat and then Is_Real_Type (Typ) then
declare
- Left_Int : constant Uint := Expr_Value (Left);
- Right_Int : constant Uint := Expr_Value (Right);
+ Left_Real : constant Ureal := Expr_Value_R (Left);
+ Right_Real : constant Ureal := Expr_Value_R (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 N_Op_Eq => Result := (Left_Real = Right_Real);
+ when N_Op_Ne => Result := (Left_Real /= Right_Real);
+ when N_Op_Lt => Result := (Left_Real < Right_Real);
+ when N_Op_Le => Result := (Left_Real <= Right_Real);
+ when N_Op_Gt => Result := (Left_Real > Right_Real);
+ when N_Op_Ge => Result := (Left_Real >= Right_Real);
when others =>
raise Program_Error;
end case;
- Fold_Uint (N, Test (Result));
+ Fold_Uint (N, Test (Result), True);
end;
- -- Real type case
+ -- For all other cases, we use Compile_Time_Compare to do the compare
else
- pragma Assert (Is_Real_Type (Typ));
-
declare
- Left_Real : constant Ureal := Expr_Value_R (Left);
- Right_Real : constant Ureal := Expr_Value_R (Right);
+ CR : constant Compare_Result :=
+ Compile_Time_Compare (Left, Right, Assume_Valid => False);
begin
+ if CR = Unknown then
+ return;
+ end if;
+
case Nkind (N) is
- when N_Op_Eq => Result := (Left_Real = Right_Real);
- when N_Op_Ne => Result := (Left_Real /= Right_Real);
- when N_Op_Lt => Result := (Left_Real < Right_Real);
- when N_Op_Le => Result := (Left_Real <= Right_Real);
- when N_Op_Gt => Result := (Left_Real > Right_Real);
- when N_Op_Ge => Result := (Left_Real >= Right_Real);
+ 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;
+
+ 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;
-
- Fold_Uint (N, Test (Result));
end;
+
+ Fold_Uint (N, Test (Result), Stat);
end if;
- Set_Is_Static_Expression (N, Stat);
Warn_On_Known_Condition (N);
end Eval_Relational_Op;
begin
-- Short circuit operations are never static in Ada 83
- if Ada_83
+ if Ada_Version = Ada_83
and then Comes_From_Source (N)
then
Check_Non_Static_Context (Left);
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);
+ Fold_Uint (N, Left_Int, Rstat);
return;
end if;
-- Otherwise the result depends on the right operand
- Fold_Uint (N, Expr_Value (Right));
+ Fold_Uint (N, Expr_Value (Right), Rstat);
return;
-
end Eval_Short_Circuit;
----------------
procedure Eval_Slice (N : Node_Id) is
Drange : constant Node_Id := Discrete_Range (N);
-
begin
if Nkind (Drange) = N_Range then
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;
-------------------------
-------------------------
procedure Eval_String_Literal (N : Node_Id) is
- T : constant Entity_Id := Etype (N);
- B : constant Entity_Id := Base_Type (T);
- I : Entity_Id;
+ Typ : constant Entity_Id := Etype (N);
+ Bas : constant Entity_Id := Base_Type (Typ);
+ Xtp : Entity_Id;
+ Len : Nat;
+ Lo : Node_Id;
begin
-- Nothing to do if error type (handles cases like default expressions
-- or generics where we have not yet fully resolved the type)
- if B = Any_Type or else B = Any_String then
+ if Bas = Any_Type or else Bas = Any_String then
return;
+ end if;
-- String literals are static if the subtype is static (RM 4.9(2)), so
-- reset the static expression flag (it was set unconditionally in
-- Analyze_String_Literal) if the subtype is non-static. We tell if
-- the subtype is static by looking at the lower bound.
- elsif not Is_OK_Static_Expression (String_Literal_Low_Bound (T)) then
+ if Ekind (Typ) = E_String_Literal_Subtype then
+ if not Is_OK_Static_Expression (String_Literal_Low_Bound (Typ)) then
+ Set_Is_Static_Expression (N, False);
+ return;
+ end if;
+
+ -- Here if Etype of string literal is normal Etype (not yet possible,
+ -- but may be possible in future!)
+
+ elsif not Is_OK_Static_Expression
+ (Type_Low_Bound (Etype (First_Index (Typ))))
+ then
Set_Is_Static_Expression (N, False);
+ return;
+ end if;
+
+ -- If original node was a type conversion, then result if non-static
- elsif Nkind (Original_Node (N)) = N_Type_Conversion then
+ if Nkind (Original_Node (N)) = N_Type_Conversion then
Set_Is_Static_Expression (N, False);
+ 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 hapen in only two ways. Either
+ -- 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.
- elsif Ada_95 then
- if Root_Type (B) = Standard_String
- or else Root_Type (B) = Standard_Wide_String
+ if Ada_Version >= Ada_95 then
+ if Root_Type (Bas) = Standard_String
+ or else
+ Root_Type (Bas) = Standard_Wide_String
then
- I := Standard_Positive;
+ Xtp := Standard_Positive;
+ else
+ Xtp := Etype (First_Index (Bas));
+ end if;
+
+ if Ekind (Typ) = E_String_Literal_Subtype then
+ Lo := String_Literal_Low_Bound (Typ);
else
- I := Etype (First_Index (B));
+ Lo := Type_Low_Bound (Etype (First_Index (Typ)));
end if;
- if String_Literal_Length (T) > String_Type_Len (B) then
+ Len := String_Length (Strval (N));
+
+ if UI_From_Int (Len) > String_Type_Len (Bas) then
Apply_Compile_Time_Constraint_Error
(N, "string literal too long for}", CE_Length_Check_Failed,
- Ent => B,
- Typ => First_Subtype (B));
+ Ent => Bas,
+ Typ => First_Subtype (Bas));
- elsif String_Literal_Length (T) = 0
- and then not Is_Generic_Type (I)
- and then Expr_Value (String_Literal_Low_Bound (T)) =
- Expr_Value (Type_Low_Bound (Base_Type (I)))
+ elsif Len = 0
+ and then not Is_Generic_Type (Xtp)
+ and then
+ Expr_Value (Lo) = Expr_Value (Type_Low_Bound (Base_Type (Xtp)))
then
Apply_Compile_Time_Constraint_Error
(N, "null string literal not allowed for}",
CE_Length_Check_Failed,
- Ent => B,
- Typ => First_Subtype (B));
+ Ent => Bas,
+ Typ => First_Subtype (Bas));
end if;
end if;
-
end Eval_String_Literal;
--------------------------
-- fixed-point type that is not to be treated as an integer (i.e. the
-- flag Conversion_OK is not set on the conversion node).
+ ------------------------------
+ -- To_Be_Treated_As_Integer --
+ ------------------------------
+
function To_Be_Treated_As_Integer (T : Entity_Id) return Boolean is
begin
return
or else (Is_Fixed_Point_Type (T) and then Conversion_OK (N));
end To_Be_Treated_As_Integer;
+ ---------------------------
+ -- To_Be_Treated_As_Real --
+ ---------------------------
+
function To_Be_Treated_As_Real (T : Entity_Id) return Boolean is
begin
return
-- Start of processing for Eval_Type_Conversion
begin
- -- Cannot fold if target type is non-static or if semantic error.
+ -- Cannot fold if target type is non-static or if semantic error
if not Is_Static_Subtype (Target_Type) then
Check_Non_Static_Context (Operand);
-- following type test, fixed-point counts as real unless the flag
-- Conversion_OK is set, in which case it counts as integer.
- -- Fold conversion, case of string type. The result is not static.
+ -- Fold conversion, case of string type. The result is not static
if Is_String_Type (Target_Type) then
- Fold_Str (N, Strval (Get_String_Val (Operand)));
- Set_Is_Static_Expression (N, False);
+ Fold_Str (N, Strval (Get_String_Val (Operand)), Static => False);
return;
if Is_Fixed_Point_Type (Target_Type) then
Fold_Ureal
- (N, UR_From_Uint (Result) * Small_Value (Target_Type));
+ (N, UR_From_Uint (Result) * Small_Value (Target_Type), Stat);
-- Otherwise result is integer literal
else
- Fold_Uint (N, Result);
+ Fold_Uint (N, Result, Stat);
end if;
end;
Result := UR_From_Uint (Expr_Value (Operand));
end if;
- Fold_Ureal (N, Result);
+ Fold_Ureal (N, Result, Stat);
end;
-- Enumeration types
else
- Fold_Uint (N, Expr_Value (Operand));
+ Fold_Uint (N, Expr_Value (Operand), Stat);
end if;
- 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;
Result := abs Rint;
end if;
- Fold_Uint (N, Result);
+ Fold_Uint (N, Result, Stat);
end;
-- Fold for real case
Result := abs Rreal;
end if;
- Fold_Ureal (N, Result);
+ Fold_Ureal (N, Result, Stat);
end;
end if;
-
- Set_Is_Static_Expression (N, Stat);
-
end Eval_Unary_Op;
-------------------------------
function Expr_Rep_Value (N : Node_Id) return Uint is
Kind : constant Node_Kind := Nkind (N);
Ent : Entity_Id;
- Vexp : Node_Id;
begin
if Is_Entity_Name (N) then
then
return Uint_0;
- -- Array reference case
-
- elsif Kind = N_Indexed_Component then
- Vexp := Constant_Array_Ref (N);
- pragma Assert (Present (Vexp));
- return Expr_Rep_Value (Vexp);
-
-- Otherwise must be character literal
+
else
pragma Assert (Kind = N_Character_Literal);
Ent := Entity (N);
-- their Pos value as usual which is the same as the Rep value.
if No (Ent) then
- return UI_From_Int (Int (Char_Literal_Value (N)));
+ return Char_Literal_Value (N);
else
return Enumeration_Rep (Ent);
end if;
CV_Ent : CV_Entry renames CV_Cache (Nat (N) mod CV_Cache_Size);
Ent : Entity_Id;
Val : Uint;
- Vexp : Node_Id;
begin
- -- If already in cache, then we know it's compile time known and
- -- we can return the value that was previously stored in the cache
- -- since compile time known values cannot change :-)
+ -- If already in cache, then we know it's compile time known and we can
+ -- return the value that was previously stored in the cache since
+ -- compile time known values cannot change.
if CV_Ent.N = N then
return CV_Ent.V;
then
Val := Uint_0;
- -- Array reference case
-
- elsif Kind = N_Indexed_Component then
- Vexp := Constant_Array_Ref (N);
- pragma Assert (Present (Vexp));
- Val := Expr_Value (Vexp);
-
-- Otherwise must be character literal
else
-- their Pos value as usual.
if No (Ent) then
- Val := UI_From_Int (Int (Char_Literal_Value (N)));
+ Val := Char_Literal_Value (N);
else
Val := Enumeration_Pos (Ent);
end if;
return Ureal_0;
end if;
- -- If we fall through, we have a node that cannot be interepreted
+ -- 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 if;
end Expr_Value_S;
+ --------------------------
+ -- Flag_Non_Static_Expr --
+ --------------------------
+
+ procedure Flag_Non_Static_Expr (Msg : String; Expr : Node_Id) is
+ begin
+ if Error_Posted (Expr) and then not All_Errors_Mode then
+ return;
+ else
+ Error_Msg_F (Msg, Expr);
+ Why_Not_Static (Expr);
+ end if;
+ end Flag_Non_Static_Expr;
+
--------------
-- Fold_Str --
--------------
- procedure Fold_Str (N : Node_Id; Val : String_Id) is
+ procedure Fold_Str (N : Node_Id; Val : String_Id; Static : Boolean) is
Loc : constant Source_Ptr := Sloc (N);
Typ : constant Entity_Id := Etype (N);
begin
Rewrite (N, Make_String_Literal (Loc, Strval => Val));
- Analyze_And_Resolve (N, Typ);
+
+ -- We now have the literal with the right value, both the actual type
+ -- and the expected type of this literal are taken from the expression
+ -- that was evaluated.
+
+ Analyze (N);
+ Set_Is_Static_Expression (N, Static);
+ Set_Etype (N, Typ);
+ Resolve (N);
end Fold_Str;
---------------
-- Fold_Uint --
---------------
- procedure Fold_Uint (N : Node_Id; Val : Uint) is
+ procedure Fold_Uint (N : Node_Id; Val : Uint; Static : Boolean) is
Loc : constant Source_Ptr := Sloc (N);
- Typ : constant Entity_Id := Etype (N);
+ Typ : Entity_Id := Etype (N);
+ Ent : Entity_Id;
begin
- -- For a result of type integer, subsitute an N_Integer_Literal node
+ -- 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
+ then
+ Ent := Entity (N);
+ else
+ Ent := Empty;
+ end if;
+
+ if Is_Private_Type (Typ) then
+ Typ := Full_View (Typ);
+ end if;
+
+ -- 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 (Etype (N)) then
+ 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
-- an N_Identifier or N_Character_Literal to represent the enumeration
-- literal corresponding to the given value, which must always be in
-- range, because appropriate tests have already been made for this.
- else pragma Assert (Is_Enumeration_Type (Etype (N)));
+ else pragma Assert (Is_Enumeration_Type (Typ));
Rewrite (N, Get_Enum_Lit_From_Pos (Etype (N), Val, Loc));
end if;
-- that was evaluated.
Analyze (N);
+ Set_Is_Static_Expression (N, Static);
Set_Etype (N, Typ);
- Resolve (N, Typ);
+ Resolve (N);
end Fold_Uint;
----------------
-- Fold_Ureal --
----------------
- procedure Fold_Ureal (N : Node_Id; Val : Ureal) is
+ procedure Fold_Ureal (N : Node_Id; Val : Ureal; Static : Boolean) is
Loc : constant Source_Ptr := Sloc (N);
Typ : constant Entity_Id := Etype (N);
+ Ent : Entity_Id;
begin
+ -- 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
+ then
+ Ent := Entity (N);
+ else
+ Ent := Empty;
+ end if;
+
Rewrite (N, Make_Real_Literal (Loc, Realval => Val));
- Analyze (N);
+
+ -- 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
+ Analyze (N);
+ Set_Is_Static_Expression (N, Static);
Set_Etype (N, Typ);
- Resolve (N, Typ);
+ Resolve (N);
end Fold_Ureal;
---------------
end if;
end Get_String_Val;
+ ----------------
+ -- Initialize --
+ ----------------
+
+ procedure Initialize is
+ begin
+ CV_Cache := (others => (Node_High_Bound, Uint_0));
+ end Initialize;
+
--------------------
-- In_Subrange_Of --
--------------------
function In_Subrange_Of
(T1 : Entity_Id;
T2 : Entity_Id;
- Fixed_Int : Boolean := False)
- return Boolean
+ Fixed_Int : Boolean := False) return Boolean
is
L1 : Node_Id;
H1 : Node_Id;
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;
end if;
-- If any exception occurs, it means that we have some bug in the compiler
- -- possibly triggered by a previous error, or by some unforseen peculiar
+ -- possibly triggered by a previous error, or by some unforeseen peculiar
-- occurrence. However, this is only an optimization attempt, so there is
-- really no point in crashing the compiler. Instead we just decide, too
-- bad, we can't figure out the answer in this case after all.
-----------------
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;
+ pragma Warnings (Off, Assume_Valid);
+ -- For now Assume_Valid is unreferenced since the current implementation
+ -- always returns False 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.
+ -- Universal types have no range limits, so always in range
if Typ = Universal_Integer or else Typ = Universal_Real then
return True;
elsif not Is_Scalar_Type (Typ) then
return False;
- -- Never in range unless we have a compile time known value.
+ -- Never in range unless we have a compile time known value
elsif not Compile_Time_Known_Value (N) then
return False;
+ -- General processing with a known compile time value
+
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);
+ Lo : Node_Id;
+ Hi : Node_Id;
+ LB_Known : Boolean;
+ UB_Known : Boolean;
begin
+ Lo := Type_Low_Bound (Typ);
+ Hi := Type_High_Bound (Typ);
+
+ LB_Known := Compile_Time_Known_Value (Lo);
+ UB_Known := Compile_Time_Known_Value (Hi);
+
-- Fixed point types should be considered as such only in
-- flag Fixed_Int is set to False.
---------------------
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;
+ pragma Warnings (Off, Assume_Valid);
+ -- For now Assume_Valid is unreferenced since the current implementation
+ -- always returns False 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.
+ -- Universal types have no range limits, so always in range
if Typ = Universal_Integer or else Typ = Universal_Real then
return False;
elsif Is_Generic_Type (Typ) then
return False;
- -- Never out of range unless we have a compile time known value.
+ -- 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);
+ Lo : Node_Id;
+ Hi : Node_Id;
+ LB_Known : Boolean;
+ UB_Known : Boolean;
begin
+ Lo := Type_Low_Bound (Typ);
+ Hi := Type_High_Bound (Typ);
+
+ LB_Known := Compile_Time_Known_Value (Lo);
+ UB_Known := Compile_Time_Known_Value (Hi);
+
-- 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).
-- Is_Static_Subtype --
-----------------------
- -- Determines if Typ is a static subtype as defined in (RM 4.9(26)).
+ -- Determines if Typ is a static subtype as defined in (RM 4.9(26))
function Is_Static_Subtype (Typ : Entity_Id) return Boolean is
Base_T : constant Entity_Id := Base_Type (Typ);
if Is_Static_Expression (N)
and then not In_Instance
- and then Ada_95
+ and then not In_Inlined_Body
+ and then Ada_Version >= Ada_95
then
-
if Nkind (Parent (N)) = N_Defining_Identifier
and then Is_Array_Type (Parent (N))
and then Present (Packed_Array_Type (Parent (N)))
-- in an instance, or when we have a non-static expression case.
else
- Warn_On_Instance := True;
Apply_Compile_Time_Constraint_Error
(N, "value not in range of}?", CE_Range_Check_Failed);
- Warn_On_Instance := False;
end if;
end Out_Of_Range;
------------------------------------
function Subtypes_Statically_Compatible
- (T1 : Entity_Id;
- T2 : Entity_Id)
- return Boolean
+ (T1 : Entity_Id;
+ T2 : Entity_Id) return Boolean
is
begin
if Is_Scalar_Type (T1) then
-- 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
+ elsif Is_Real_Type (T1) /= Is_Real_Type (T2) then
return False;
-- Here we check the bounds
-- 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 uncontrained base type. In this
+ -- 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.
or else Comes_From_Source (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.
+
+ elsif Is_Generic_Type (T1)
+ and then Is_Generic_Type (T2)
+ and then (Is_Constrained (T1) /= Is_Constrained (T2))
+ then
+ return False;
end if;
-- If there was an error in either range, then just assume
-- Type with discriminants
elsif Has_Discriminants (T1) or else Has_Discriminants (T2) then
+
+ -- Because of view exchanges in multiple instantiations, conformance
+ -- checking might try to match a partial view of a type with no
+ -- discriminants with a full view that has defaulted discriminants.
+ -- In such a case, use the discriminant constraint of the full view,
+ -- which must exist because we know that the two subtypes have the
+ -- same base type.
+
if Has_Discriminants (T1) /= Has_Discriminants (T2) then
- return False;
+ if In_Instance then
+ if Is_Private_Type (T2)
+ and then Present (Full_View (T2))
+ and then Has_Discriminants (Full_View (T2))
+ then
+ return Subtypes_Statically_Match (T1, Full_View (T2));
+
+ elsif Is_Private_Type (T1)
+ and then Present (Full_View (T1))
+ and then Has_Discriminants (Full_View (T1))
+ then
+ return Subtypes_Statically_Match (Full_View (T1), T2);
+
+ else
+ return False;
+ end if;
+ else
+ return False;
+ end if;
end if;
declare
DL1 : constant Elist_Id := Discriminant_Constraint (T1);
DL2 : constant Elist_Id := Discriminant_Constraint (T2);
- DA1 : Elmt_Id := First_Elmt (DL1);
- DA2 : Elmt_Id := First_Elmt (DL2);
+ DA1 : Elmt_Id;
+ DA2 : Elmt_Id;
begin
if DL1 = DL2 then
return True;
-
elsif Is_Constrained (T1) /= Is_Constrained (T2) then
return False;
end if;
- while Present (DA1) loop
- declare
- Expr1 : constant Node_Id := Node (DA1);
- Expr2 : constant Node_Id := Node (DA2);
+ -- Now loop through the discriminant constraints
- begin
- if not Is_Static_Expression (Expr1)
- or else not Is_Static_Expression (Expr2)
- then
- return False;
+ -- Note: the guard here seems necessary, since it is possible at
+ -- least for DL1 to be No_Elist. Not clear this is reasonable ???
- -- If either expression raised a constraint error,
- -- consider the expressions as matching, since this
- -- helps to prevent cascading errors.
+ if Present (DL1) and then Present (DL2) then
+ DA1 := First_Elmt (DL1);
+ DA2 := First_Elmt (DL2);
+ while Present (DA1) loop
+ declare
+ Expr1 : constant Node_Id := Node (DA1);
+ Expr2 : constant Node_Id := Node (DA2);
- elsif Raises_Constraint_Error (Expr1)
- or else Raises_Constraint_Error (Expr2)
- then
- null;
+ begin
+ if not Is_Static_Expression (Expr1)
+ or else not Is_Static_Expression (Expr2)
+ then
+ return False;
- elsif Expr_Value (Expr1) /= Expr_Value (Expr2) then
- return False;
- end if;
- end;
+ -- If either expression raised a constraint error,
+ -- consider the expressions as matching, since this
+ -- helps to prevent cascading errors.
- Next_Elmt (DA1);
- Next_Elmt (DA2);
- end loop;
+ elsif Raises_Constraint_Error (Expr1)
+ or else Raises_Constraint_Error (Expr2)
+ then
+ null;
+
+ elsif Expr_Value (Expr1) /= Expr_Value (Expr2) then
+ return False;
+ end if;
+ end;
+
+ Next_Elmt (DA1);
+ Next_Elmt (DA2);
+ end loop;
+ end if;
end;
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.
elsif
Has_Unknown_Discriminants (T1) /= Has_Unknown_Discriminants (T2)
then
- return False;
+ return
+ Is_Generic_Actual_Type (T1) or else Is_Generic_Actual_Type (T2);
-- Array type
end;
elsif Is_Access_Type (T1) then
- return Subtypes_Statically_Match
- (Designated_Type (T1),
- Designated_Type (T2));
+ 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
+ then
+ return
+ Subtype_Conformant
+ (Designated_Type (T1),
+ Designated_Type (T2));
+ else
+ return
+ Subtypes_Statically_Match
+ (Designated_Type (T1),
+ Designated_Type (T2))
+ and then Is_Access_Constant (T1) = Is_Access_Constant (T2);
+ end if;
-- All other types definitely match
is
begin
Stat := False;
+ Fold := False;
+
+ if Debug_Flag_Dot_F and then In_Extended_Main_Source_Unit (N) then
+ return;
+ end if;
-- If operand is Any_Type, just propagate to result and do not
-- try to fold, this prevents cascaded errors.
if Etype (Op1) = Any_Type then
Set_Etype (N, Any_Type);
- Fold := False;
return;
-- If operand raises constraint error, then replace node N with the
elsif Raises_Constraint_Error (Op1) then
Rewrite_In_Raise_CE (N, Op1);
- Fold := False;
return;
-- If the operand is not static, then the result is not static, and
and then Is_Generic_Type (Etype (Op1))
then
Check_Non_Static_Context (Op1);
- Fold := False;
return;
-- Here we have the case of an operand whose type is OK, which is
begin
Stat := False;
+ Fold := False;
+
+ if Debug_Flag_Dot_F and then In_Extended_Main_Source_Unit (N) then
+ return;
+ end if;
-- If either operand is Any_Type, just propagate to result and
-- do not try to fold, this prevents cascaded errors.
if Etype (Op1) = Any_Type or else Etype (Op2) = Any_Type then
Set_Etype (N, Any_Type);
- Fold := False;
return;
-- If left operand raises constraint error, then replace node N with
Rewrite_In_Raise_CE (N, Op1);
Set_Is_Static_Expression (N, Rstat);
- Fold := False;
return;
-- Similar processing for the case of the right operand. Note that
Rewrite_In_Raise_CE (N, Op2);
Set_Is_Static_Expression (N, Rstat);
- Fold := False;
return;
- -- Exclude expressions of a generic modular type, as above.
+ -- Exclude expressions of a generic modular type, as above
elsif Is_Modular_Integer_Type (Etype (Op1))
and then Is_Generic_Type (Etype (Op1))
then
Check_Non_Static_Context (Op1);
- Fold := False;
return;
-- If result is not static, then check non-static contexts on operands
end loop;
end To_Bits;
+ --------------------
+ -- Why_Not_Static --
+ --------------------
+
+ procedure Why_Not_Static (Expr : Node_Id) is
+ N : constant Node_Id := Original_Node (Expr);
+ Typ : Entity_Id;
+ 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.
+
+ -------------------------
+ -- Why_Not_Static_List --
+ -------------------------
+
+ procedure Why_Not_Static_List (L : List_Id) is
+ N : Node_Id;
+
+ begin
+ if Is_Non_Empty_List (L) then
+ N := First (L);
+ while Present (N) loop
+ Why_Not_Static (N);
+ Next (N);
+ end loop;
+ end if;
+ end 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 Debug_Flag_2 then
+ return;
+ end if;
+
+ -- Ignore call on error or empty node
+
+ if No (Expr) or else Nkind (Expr) = N_Error then
+ return;
+ end if;
+
+ -- Preprocessing for sub expressions
+
+ if Nkind (Expr) in N_Subexpr then
+
+ -- Nothing to do if expression is static
+
+ if Is_OK_Static_Expression (Expr) then
+ return;
+ end if;
+
+ -- Test for constraint error raised
+
+ if Raises_Constraint_Error (Expr) then
+ Error_Msg_N
+ ("expression raises exception, cannot be static " &
+ "(RM 4.9(34))!", N);
+ return;
+ end if;
+
+ -- If no type, then something is pretty wrong, so ignore
+
+ Typ := Etype (Expr);
+
+ if No (Typ) then
+ return;
+ end if;
+
+ -- Type must be scalar or string type
+
+ if not Is_Scalar_Type (Typ)
+ and then not Is_String_Type (Typ)
+ then
+ Error_Msg_N
+ ("static expression must have scalar or string type " &
+ "(RM 4.9(2))!", N);
+ return;
+ end if;
+ end if;
+
+ -- If we got through those checks, test particular node kind
+
+ case Nkind (N) is
+ when N_Expanded_Name | N_Identifier | N_Operator_Symbol =>
+ E := Entity (N);
+
+ if Is_Named_Number (E) then
+ null;
+
+ elsif Ekind (E) = E_Constant then
+ if not Is_Static_Expression (Constant_Value (E)) then
+ Error_Msg_NE
+ ("& is not a static constant (RM 4.9(5))!", N, E);
+ end if;
+
+ else
+ Error_Msg_NE
+ ("& is not static constant or named number " &
+ "(RM 4.9(5))!", N, E);
+ end if;
+
+ 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);
+
+ else
+ Why_Not_Static (Left_Opnd (N));
+ Why_Not_Static (Right_Opnd (N));
+ end if;
+
+ when N_Unary_Op =>
+ Why_Not_Static (Right_Opnd (N));
+
+ when N_Attribute_Reference =>
+ Why_Not_Static_List (Expressions (N));
+
+ E := Etype (Prefix (N));
+
+ if E = Standard_Void_Type then
+ return;
+ end if;
+
+ -- Special case non-scalar'Size since this is a common error
+
+ if Attribute_Name (N) = Name_Size then
+ Error_Msg_N
+ ("size attribute is only static for static scalar type " &
+ "(RM 4.9(7,8))", N);
+
+ -- Flag array cases
+
+ elsif Is_Array_Type (E) then
+ if Attribute_Name (N) /= Name_First
+ and then
+ Attribute_Name (N) /= Name_Last
+ and then
+ Attribute_Name (N) /= Name_Length
+ then
+ Error_Msg_N
+ ("static array attribute must be Length, First, or Last " &
+ "(RM 4.9(8))!", N);
+
+ -- Since we know the expression is not-static (we already
+ -- tested for this, must mean array is not static).
+
+ else
+ Error_Msg_N
+ ("prefix is non-static array (RM 4.9(8))!", Prefix (N));
+ end if;
+
+ return;
+
+ -- Special case generic types, since again this is a common
+ -- source of confusion.
+
+ elsif Is_Generic_Actual_Type (E)
+ or else
+ Is_Generic_Type (E)
+ then
+ Error_Msg_N
+ ("attribute of generic type is never static " &
+ "(RM 4.9(7,8))!", N);
+
+ elsif Is_Static_Subtype (E) then
+ null;
+
+ elsif Is_Scalar_Type (E) then
+ Error_Msg_N
+ ("prefix type for attribute is not static scalar subtype " &
+ "(RM 4.9(7))!", N);
+
+ else
+ Error_Msg_N
+ ("static attribute must apply to array/scalar type " &
+ "(RM 4.9(7,8))!", N);
+ end if;
+
+ when N_String_Literal =>
+ Error_Msg_N
+ ("subtype of string literal is non-static (RM 4.9(4))!", N);
+
+ when N_Explicit_Dereference =>
+ Error_Msg_N
+ ("explicit dereference is never static (RM 4.9)!", N);
+
+ when N_Function_Call =>
+ Why_Not_Static_List (Parameter_Associations (N));
+ Error_Msg_N ("non-static function call (RM 4.9(6,18))!", N);
+
+ when N_Parameter_Association =>
+ Why_Not_Static (Explicit_Actual_Parameter (N));
+
+ when N_Indexed_Component =>
+ Error_Msg_N
+ ("indexed component is never static (RM 4.9)!", N);
+
+ when N_Procedure_Call_Statement =>
+ Error_Msg_N
+ ("procedure call is never static (RM 4.9)!", N);
+
+ when N_Qualified_Expression =>
+ Why_Not_Static (Expression (N));
+
+ when N_Aggregate | N_Extension_Aggregate =>
+ Error_Msg_N
+ ("an aggregate is never static (RM 4.9)!", N);
+
+ when N_Range =>
+ Why_Not_Static (Low_Bound (N));
+ Why_Not_Static (High_Bound (N));
+
+ when N_Range_Constraint =>
+ Why_Not_Static (Range_Expression (N));
+
+ when N_Subtype_Indication =>
+ Why_Not_Static (Constraint (N));
+
+ when N_Selected_Component =>
+ Error_Msg_N
+ ("selected component is never static (RM 4.9)!", N);
+
+ when N_Slice =>
+ Error_Msg_N
+ ("slice is never static (RM 4.9)!", N);
+
+ 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)))
+ then
+ Error_Msg_N
+ ("static conversion requires static scalar subtype result " &
+ "(RM 4.9(9))!", N);
+ end if;
+
+ when N_Unchecked_Type_Conversion =>
+ Error_Msg_N
+ ("unchecked type conversion is never static (RM 4.9)!", N);
+
+ when others =>
+ null;
+
+ end case;
+ end Why_Not_Static;
+
end Sem_Eval;
OSDN Git Service
