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------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- S E M _ C A S E --
-- --
-- B o d y --
-- --
-- Copyright (C) 1996-2002 Free Software Foundation, Inc. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- ware Foundation; either version 2, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
-- for more details. You should have received a copy of the GNU General --
-- Public License distributed with GNAT; see file COPYING. If not, write --
-- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
-- MA 02111-1307, USA. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
with Atree; use Atree;
with Einfo; use Einfo;
with Errout; use Errout;
with Namet; use Namet;
with Nlists; use Nlists;
with Sem; use Sem;
with Sem_Eval; use Sem_Eval;
with Sem_Res; use Sem_Res;
with Sem_Util; use Sem_Util;
with Sem_Type; use Sem_Type;
with Snames; use Snames;
with Stand; use Stand;
with Sinfo; use Sinfo;
with Uintp; use Uintp;
with GNAT.Heap_Sort_A; use GNAT.Heap_Sort_A;
package body Sem_Case is
-----------------------
-- Local Subprograms --
-----------------------
type Sort_Choice_Table_Type is array (Nat range <>) of Choice_Bounds;
-- This new array type is used as the actual table type for sorting
-- discrete choices. The reason for not using Choice_Table_Type, is that
-- in Sort_Choice_Table_Type we reserve entry 0 for the sorting algortim
-- (this is not absolutely necessary but it makes the code more
-- efficient).
procedure Check_Choices
(Choice_Table : in out Sort_Choice_Table_Type;
Bounds_Type : Entity_Id;
Others_Present : Boolean;
Msg_Sloc : Source_Ptr);
-- This is the procedure which verifies that a set of case statement,
-- array aggregate or record variant choices has no duplicates, and
-- covers the range specified by Bounds_Type. Choice_Table contains the
-- discrete choices to check. These must start at position 1.
-- Furthermore Choice_Table (0) must exist. This element is used by
-- the sorting algorithm as a temporary. Others_Present is a flag
-- indicating whether or not an Others choice is present. Finally
-- Msg_Sloc gives the source location of the construct containing the
-- choices in the Choice_Table.
function Choice_Image (Value : Uint; Ctype : Entity_Id) return Name_Id;
-- Given a Pos value of enumeration type Ctype, returns the name
-- ID of an appropriate string to be used in error message output.
-------------------
-- Check_Choices --
-------------------
procedure Check_Choices
(Choice_Table : in out Sort_Choice_Table_Type;
Bounds_Type : Entity_Id;
Others_Present : Boolean;
Msg_Sloc : Source_Ptr)
is
function Lt_Choice (C1, C2 : Natural) return Boolean;
-- Comparison routine for comparing Choice_Table entries.
-- Use the lower bound of each Choice as the key.
procedure Move_Choice (From : Natural; To : Natural);
-- Move routine for sorting the Choice_Table.
procedure Issue_Msg (Value1 : Node_Id; Value2 : Node_Id);
procedure Issue_Msg (Value1 : Node_Id; Value2 : Uint);
procedure Issue_Msg (Value1 : Uint; Value2 : Node_Id);
procedure Issue_Msg (Value1 : Uint; Value2 : Uint);
-- Issue an error message indicating that there are missing choices,
-- followed by the image of the missing choices themselves which lie
-- between Value1 and Value2 inclusive.
---------------
-- Issue_Msg --
---------------
procedure Issue_Msg (Value1 : Node_Id; Value2 : Node_Id) is
begin
Issue_Msg (Expr_Value (Value1), Expr_Value (Value2));
end Issue_Msg;
procedure Issue_Msg (Value1 : Node_Id; Value2 : Uint) is
begin
Issue_Msg (Expr_Value (Value1), Value2);
end Issue_Msg;
procedure Issue_Msg (Value1 : Uint; Value2 : Node_Id) is
begin
Issue_Msg (Value1, Expr_Value (Value2));
end Issue_Msg;
procedure Issue_Msg (Value1 : Uint; Value2 : Uint) is
begin
-- In some situations, we call this with a null range, and
-- obviously we don't want to complain in this case!
if Value1 > Value2 then
return;
end if;
-- Case of only one value that is missing
if Value1 = Value2 then
if Is_Integer_Type (Bounds_Type) then
Error_Msg_Uint_1 := Value1;
Error_Msg ("missing case value: ^!", Msg_Sloc);
else
Error_Msg_Name_1 := Choice_Image (Value1, Bounds_Type);
Error_Msg ("missing case value: %!", Msg_Sloc);
end if;
-- More than one choice value, so print range of values
else
if Is_Integer_Type (Bounds_Type) then
Error_Msg_Uint_1 := Value1;
Error_Msg_Uint_2 := Value2;
Error_Msg ("missing case values: ^ .. ^!", Msg_Sloc);
else
Error_Msg_Name_1 := Choice_Image (Value1, Bounds_Type);
Error_Msg_Name_2 := Choice_Image (Value2, Bounds_Type);
Error_Msg ("missing case values: % .. %!", Msg_Sloc);
end if;
end if;
end Issue_Msg;
---------------
-- Lt_Choice --
---------------
function Lt_Choice (C1, C2 : Natural) return Boolean is
begin
return
Expr_Value (Choice_Table (Nat (C1)).Lo)
<= Expr_Value (Choice_Table (Nat (C2)).Lo);
end Lt_Choice;
-----------------
-- Move_Choice --
-----------------
procedure Move_Choice (From : Natural; To : Natural) is
begin
Choice_Table (Nat (To)) := Choice_Table (Nat (From));
end Move_Choice;
-- Variables local to Check_Choices
Choice : Node_Id;
Bounds_Lo : constant Node_Id := Type_Low_Bound (Bounds_Type);
Bounds_Hi : constant Node_Id := Type_High_Bound (Bounds_Type);
Prev_Choice : Node_Id;
Hi : Uint;
Lo : Uint;
Prev_Hi : Uint;
-- Start processing for Check_Choices
begin
-- Choice_Table must start at 0 which is an unused location used
-- by the sorting algorithm. However the first valid position for
-- a discrete choice is 1.
pragma Assert (Choice_Table'First = 0);
if Choice_Table'Last = 0 then
if not Others_Present then
Issue_Msg (Bounds_Lo, Bounds_Hi);
end if;
return;
end if;
Sort
(Positive (Choice_Table'Last),
Move_Choice'Unrestricted_Access,
Lt_Choice'Unrestricted_Access);
Lo := Expr_Value (Choice_Table (1).Lo);
Hi := Expr_Value (Choice_Table (1).Hi);
Prev_Hi := Hi;
if not Others_Present and then Expr_Value (Bounds_Lo) < Lo then
Issue_Msg (Bounds_Lo, Lo - 1);
end if;
for J in 2 .. Choice_Table'Last loop
Lo := Expr_Value (Choice_Table (J).Lo);
Hi := Expr_Value (Choice_Table (J).Hi);
if Lo <= Prev_Hi then
Prev_Choice := Choice_Table (J - 1).Node;
Choice := Choice_Table (J).Node;
if Sloc (Prev_Choice) <= Sloc (Choice) then
Error_Msg_Sloc := Sloc (Prev_Choice);
Error_Msg_N ("duplication of choice value#", Choice);
else
Error_Msg_Sloc := Sloc (Choice);
Error_Msg_N ("duplication of choice value#", Prev_Choice);
end if;
elsif not Others_Present and then Lo /= Prev_Hi + 1 then
Issue_Msg (Prev_Hi + 1, Lo - 1);
end if;
Prev_Hi := Hi;
end loop;
if not Others_Present and then Expr_Value (Bounds_Hi) > Hi then
Issue_Msg (Hi + 1, Bounds_Hi);
end if;
end Check_Choices;
------------------
-- Choice_Image --
------------------
function Choice_Image (Value : Uint; Ctype : Entity_Id) return Name_Id is
Rtp : constant Entity_Id := Root_Type (Ctype);
Lit : Entity_Id;
C : Int;
begin
-- For character, or wide character. If we are in 7-bit ASCII graphic
-- range, then build and return appropriate character literal name
if Rtp = Standard_Character
or else Rtp = Standard_Wide_Character
then
C := UI_To_Int (Value);
if C in 16#20# .. 16#7E# then
Set_Character_Literal_Name (Char_Code (UI_To_Int (Value)));
return Name_Find;
end if;
-- For user defined enumeration type, find enum/char literal
else
Lit := First_Literal (Rtp);
for J in 1 .. UI_To_Int (Value) loop
Next_Literal (Lit);
end loop;
-- If enumeration literal, just return its value
if Nkind (Lit) = N_Defining_Identifier then
return Chars (Lit);
-- For character literal, get the name and use it if it is
-- for a 7-bit ASCII graphic character in 16#20#..16#7E#.
else
Get_Decoded_Name_String (Chars (Lit));
if Name_Len = 3
and then Name_Buffer (2) in
Character'Val (16#20#) .. Character'Val (16#7E#)
then
return Chars (Lit);
end if;
end if;
end if;
-- If we fall through, we have a character literal which is not in
-- the 7-bit ASCII graphic set. For such cases, we construct the
-- name "type'val(nnn)" where type is the choice type, and nnn is
-- the pos value passed as an argument to Choice_Image.
Get_Name_String (Chars (First_Subtype (Ctype)));
Name_Len := Name_Len + 1;
Name_Buffer (Name_Len) := ''';
Name_Len := Name_Len + 1;
Name_Buffer (Name_Len) := 'v';
Name_Len := Name_Len + 1;
Name_Buffer (Name_Len) := 'a';
Name_Len := Name_Len + 1;
Name_Buffer (Name_Len) := 'l';
Name_Len := Name_Len + 1;
Name_Buffer (Name_Len) := '(';
UI_Image (Value);
for J in 1 .. UI_Image_Length loop
Name_Len := Name_Len + 1;
Name_Buffer (Name_Len) := UI_Image_Buffer (J);
end loop;
Name_Len := Name_Len + 1;
Name_Buffer (Name_Len) := ')';
return Name_Find;
end Choice_Image;
-----------
-- No_OP --
-----------
procedure No_OP (C : Node_Id) is
pragma Warnings (Off, C);
begin
null;
end No_OP;
--------------------------------
-- Generic_Choices_Processing --
--------------------------------
package body Generic_Choices_Processing is
---------------------
-- Analyze_Choices --
---------------------
procedure Analyze_Choices
(N : Node_Id;
Subtyp : Entity_Id;
Choice_Table : in out Choice_Table_Type;
Last_Choice : out Nat;
Raises_CE : out Boolean;
Others_Present : out Boolean)
is
Nb_Choices : constant Nat := Choice_Table'Length;
Sort_Choice_Table : Sort_Choice_Table_Type (0 .. Nb_Choices);
Choice_Type : constant Entity_Id := Base_Type (Subtyp);
-- The actual type against which the discrete choices are
-- resolved. Note that this type is always the base type not the
-- subtype of the ruling expression, index or discriminant.
Bounds_Type : Entity_Id;
-- The type from which are derived the bounds of the values
-- covered by th discrete choices (see 3.8.1 (4)). If a discrete
-- choice specifies a value outside of these bounds we have an error.
Bounds_Lo : Uint;
Bounds_Hi : Uint;
-- The actual bounds of the above type.
Expected_Type : Entity_Id;
-- The expected type of each choice. Equal to Choice_Type, except
-- if the expression is universal, in which case the choices can
-- be of any integer type.
procedure Check (Choice : Node_Id; Lo, Hi : Node_Id);
-- Checks the validity of the bounds of a choice. When the bounds
-- are static and no error occurred the bounds are entered into
-- the choices table so that they can be sorted later on.
-----------
-- Check --
-----------
procedure Check (Choice : Node_Id; Lo, Hi : Node_Id) is
Lo_Val : Uint;
Hi_Val : Uint;
begin
-- First check if an error was already detected on either bounds
if Etype (Lo) = Any_Type or else Etype (Hi) = Any_Type then
return;
-- Do not insert non static choices in the table to be sorted
elsif not Is_Static_Expression (Lo)
or else not Is_Static_Expression (Hi)
then
Process_Non_Static_Choice (Choice);
return;
-- Ignore range which raise constraint error
elsif Raises_Constraint_Error (Lo)
or else Raises_Constraint_Error (Hi)
then
Raises_CE := True;
return;
-- Otherwise we have an OK static choice
else
Lo_Val := Expr_Value (Lo);
Hi_Val := Expr_Value (Hi);
-- Do not insert null ranges in the choices table
if Lo_Val > Hi_Val then
Process_Empty_Choice (Choice);
return;
end if;
end if;
-- Check for bound out of range.
if Lo_Val < Bounds_Lo then
if Is_Integer_Type (Bounds_Type) then
Error_Msg_Uint_1 := Bounds_Lo;
Error_Msg_N ("minimum allowed choice value is^", Lo);
else
Error_Msg_Name_1 := Choice_Image (Bounds_Lo, Bounds_Type);
Error_Msg_N ("minimum allowed choice value is%", Lo);
end if;
elsif Hi_Val > Bounds_Hi then
if Is_Integer_Type (Bounds_Type) then
Error_Msg_Uint_1 := Bounds_Hi;
Error_Msg_N ("maximum allowed choice value is^", Hi);
else
Error_Msg_Name_1 := Choice_Image (Bounds_Hi, Bounds_Type);
Error_Msg_N ("maximum allowed choice value is%", Hi);
end if;
end if;
-- We still store the bounds in the table, even if they are out
-- of range, since this may prevent unnecessary cascaded errors
-- for values that are covered by such an excessive range.
Last_Choice := Last_Choice + 1;
Sort_Choice_Table (Last_Choice).Lo := Lo;
Sort_Choice_Table (Last_Choice).Hi := Hi;
Sort_Choice_Table (Last_Choice).Node := Choice;
end Check;
-- Variables local to Analyze_Choices
Alt : Node_Id;
-- A case statement alternative, an array aggregate component
-- association or a variant in a record type declaration
Choice : Node_Id;
Kind : Node_Kind;
-- The node kind of the current Choice.
E : Entity_Id;
-- Start of processing for Analyze_Choices
begin
Last_Choice := 0;
Raises_CE := False;
Others_Present := False;
-- If Subtyp is not a static subtype Ada 95 requires then we use
-- the bounds of its base type to determine the values covered by
-- the discrete choices.
if Is_OK_Static_Subtype (Subtyp) then
Bounds_Type := Subtyp;
else
Bounds_Type := Choice_Type;
end if;
-- Obtain static bounds of type, unless this is a generic formal
-- discrete type for which all choices will be non-static.
if not Is_Generic_Type (Root_Type (Bounds_Type))
or else Ekind (Bounds_Type) /= E_Enumeration_Type
then
Bounds_Lo := Expr_Value (Type_Low_Bound (Bounds_Type));
Bounds_Hi := Expr_Value (Type_High_Bound (Bounds_Type));
end if;
if Choice_Type = Universal_Integer then
Expected_Type := Any_Integer;
else
Expected_Type := Choice_Type;
end if;
-- Now loop through the case statement alternatives or array
-- aggregate component associations or record variants.
Alt := First (Get_Alternatives (N));
while Present (Alt) loop
-- If pragma, just analyze it
if Nkind (Alt) = N_Pragma then
Analyze (Alt);
-- Otherwise check each choice against its base type
else
Choice := First (Get_Choices (Alt));
while Present (Choice) loop
Analyze (Choice);
Kind := Nkind (Choice);
-- Choice is a Range
if Kind = N_Range
or else (Kind = N_Attribute_Reference
and then Attribute_Name (Choice) = Name_Range)
then
Resolve (Choice, Expected_Type);
Check (Choice, Low_Bound (Choice), High_Bound (Choice));
-- Choice is a subtype name
elsif Is_Entity_Name (Choice)
and then Is_Type (Entity (Choice))
then
if not Covers (Expected_Type, Etype (Choice)) then
Wrong_Type (Choice, Choice_Type);
else
E := Entity (Choice);
if not Is_Static_Subtype (E) then
Process_Non_Static_Choice (Choice);
else
Check
(Choice, Type_Low_Bound (E), Type_High_Bound (E));
end if;
end if;
-- Choice is a subtype indication
elsif Kind = N_Subtype_Indication then
Resolve_Discrete_Subtype_Indication
(Choice, Expected_Type);
if Etype (Choice) /= Any_Type then
declare
C : constant Node_Id := Constraint (Choice);
R : constant Node_Id := Range_Expression (C);
L : constant Node_Id := Low_Bound (R);
H : constant Node_Id := High_Bound (R);
begin
E := Entity (Subtype_Mark (Choice));
if not Is_Static_Subtype (E) then
Process_Non_Static_Choice (Choice);
else
if Is_OK_Static_Expression (L)
and then Is_OK_Static_Expression (H)
then
if Expr_Value (L) > Expr_Value (H) then
Process_Empty_Choice (Choice);
else
if Is_Out_Of_Range (L, E) then
Apply_Compile_Time_Constraint_Error
(L, "static value out of range",
CE_Range_Check_Failed);
end if;
if Is_Out_Of_Range (H, E) then
Apply_Compile_Time_Constraint_Error
(H, "static value out of range",
CE_Range_Check_Failed);
end if;
end if;
end if;
Check (Choice, L, H);
end if;
end;
end if;
-- The others choice is only allowed for the last
-- alternative and as its only choice.
elsif Kind = N_Others_Choice then
if not (Choice = First (Get_Choices (Alt))
and then Choice = Last (Get_Choices (Alt))
and then Alt = Last (Get_Alternatives (N)))
then
Error_Msg_N
("the choice OTHERS must appear alone and last",
Choice);
return;
end if;
Others_Present := True;
-- Only other possibility is an expression
else
Resolve (Choice, Expected_Type);
Check (Choice, Choice, Choice);
end if;
Next (Choice);
end loop;
Process_Associated_Node (Alt);
end if;
Next (Alt);
end loop;
Check_Choices
(Sort_Choice_Table (0 .. Last_Choice),
Bounds_Type,
Others_Present or else (Choice_Type = Universal_Integer),
Sloc (N));
-- Now copy the sorted discrete choices
for J in 1 .. Last_Choice loop
Choice_Table (Choice_Table'First - 1 + J) := Sort_Choice_Table (J);
end loop;
end Analyze_Choices;
-----------------------
-- Number_Of_Choices --
-----------------------
function Number_Of_Choices (N : Node_Id) return Nat is
Alt : Node_Id;
-- A case statement alternative, an array aggregate component
-- association or a record variant.
Choice : Node_Id;
Count : Nat := 0;
begin
if not Present (Get_Alternatives (N)) then
return 0;
end if;
Alt := First_Non_Pragma (Get_Alternatives (N));
while Present (Alt) loop
Choice := First (Get_Choices (Alt));
while Present (Choice) loop
if Nkind (Choice) /= N_Others_Choice then
Count := Count + 1;
end if;
Next (Choice);
end loop;
Next_Non_Pragma (Alt);
end loop;
return Count;
end Number_Of_Choices;
end Generic_Choices_Processing;
end Sem_Case;
|