a-textio.adb, [...]: Extensive changes to private part for wide character encoding

2007-12-06  Robert Dewar  <dewar@adacore.com>

	* a-textio.adb, a-textio.ads: 
	Extensive changes to private part for wide character encoding

	* a-witeio.ads, a-witeio.adb, a-ztexio.ads, a-ztexio.adb
	(Look_Ahead): Fix mishandling of encoded sequences
	Move declaration of Wch_Con to private part (should not be visible)

	* ali.adb (Scan_ALI): Set default encoding method to brackets instead of
	UTF-8. Probably this is never used, but if it is, brackets is
	clearly correct.

	* bindgen.adb (Get_WC_Encoding): New procedure to properly handle
	setting wide character encoding for no main program case and when
	encoding is specified using -W?
	Initialize stack limit of environment task if stack limit method of
	stack checking is enabled.
	(Gen_Adainit_Ada): Use Get_WC_Encoding to output encoding method
	(Gen_Adainit_C): Use Get_WC_Encoding to output encoding method
	(Get_Main_Unit_Name): New function.
	(Gen_Adainit_Ada): Add call to main program for .NET when needed.
	(Gen_Output_File): Set Bind_Main_Program to True for .NET

	* bindusg.adb: Add line for -Wx switch

	* s-wchcon.adb, s-wchcon.ads: (Is_Start_Of_Encoding): New function
	Add comments
	Add new useful constant WC_Longest_Sequences

	* switch-b.adb: Clean up handling of -Wx switch
	For -gnatWx, set Wide_Character_Encoding_Method_Specified

	* switch-c.adb: -gnatg activates warning on assertion errors
	For -gnatWx, set Wide_Character_Encoding_Method_Specified

	* s-wchcon.adb: (Is_Start_Of_Encoding): New function

From-SVN: r130817

13 files changed, 740 insertions, 163 deletions

diff --git a/gcc/ada/a-textio.adb b/gcc/ada/a-textio.adb
index c8d5843..3711ab0 100644
--- a/gcc/ada/a-textio.adb
+++ b/gcc/ada/a-textio.adb
@@ -36,6 +36,8 @@ with Interfaces.C_Streams; use Interfaces.C_Streams;
 
 with System.File_IO;
 with System.CRTL;
+with System.WCh_Cnv;       use System.WCh_Cnv;
+with System.WCh_Con;       use System.WCh_Con;
 
 with Ada.Unchecked_Conversion;
 with Ada.Unchecked_Deallocation;
@@ -55,6 +57,45 @@ package body Ada.Text_IO is
 
    use type System.CRTL.size_t;
 
+   WC_Encoding : Character;
+   pragma Import (C, WC_Encoding, "__gl_wc_encoding");
+
+   -----------------------
+   -- Local Subprograms --
+   -----------------------
+
+   function Getc_Immed (File : File_Type) return int;
+   --  This routine is identical to Getc, except that the read is done in
+   --  Get_Immediate mode (i.e. without waiting for a line return).
+
+   function Get_Upper_Half_Char
+     (C    : Character;
+      File : File_Type) return Character;
+   --  This function is shared by Get and Get_Immediate to extract an encoded
+   --  upper half character value from the given File. The first byte has
+   --  already been read and is passed in C. The character value is returned as
+   --  the result, and the file pointer is bumped past the character.
+   --  Constraint_Error is raised if the encoded value is outside the bounds of
+   --  type Character.
+
+   function Get_Upper_Half_Char_Immed
+     (C    : Character;
+      File : File_Type) return Character;
+   --  This routine is identical to Get_Upper_Half_Char, except that the reads
+   --  are done in Get_Immediate mode (i.e. without waiting for a line return).
+
+   function Has_Upper_Half_Character (Item : String) return Boolean;
+   --  Returns True if any of the characters is in the range 16#80#-16#FF#
+
+   procedure Put_Encoded (File : File_Type; Char : Character);
+   --  Called to output a character Char to the given File, when the encoding
+   --  method for the file is other than brackets, and Char is upper half.
+
+   procedure Set_WCEM (File : in out File_Type);
+   --  Called by Open and Create to set the wide character encoding method for
+   --  the file, processing a WCEM form parameter if one is present. File is
+   --  IN OUT because it may be closed in case of an error.
+
    -------------------
    -- AFCB_Allocate --
    -------------------
@@ -155,6 +196,7 @@ package body Ada.Text_IO is
                 Text      => True);
 
       File.Self := File;
+      Set_WCEM (File);
    end Create;
 
    -------------------
@@ -218,8 +260,10 @@ package body Ada.Text_IO is
    begin
       FIO.Check_Read_Status (AP (File));
 
-      if File.Before_LM then
+      if File.Before_Upper_Half_Character then
+         return False;
 
+      elsif File.Before_LM then
          if File.Before_LM_PM then
             return Nextc (File) = EOF;
          end if;
@@ -276,7 +320,10 @@ package body Ada.Text_IO is
    begin
       FIO.Check_Read_Status (AP (File));
 
-      if File.Before_LM then
+      if File.Before_Upper_Half_Character then
+         return False;
+
+      elsif File.Before_LM then
          return True;
 
       else
@@ -310,6 +357,9 @@ package body Ada.Text_IO is
       if not File.Is_Regular_File then
          return False;
 
+      elsif File.Before_Upper_Half_Character then
+         return False;
+
       elsif File.Before_LM then
          if File.Before_LM_PM then
             return True;
@@ -389,7 +439,11 @@ package body Ada.Text_IO is
    begin
       FIO.Check_Read_Status (AP (File));
 
-      if File.Before_LM then
+      if File.Before_Upper_Half_Character then
+         File.Before_Upper_Half_Character := False;
+         Item := File.Saved_Upper_Half_Character;
+
+      elsif File.Before_LM then
          File.Before_LM := False;
          File.Col := 1;
 
@@ -486,40 +540,39 @@ package body Ada.Text_IO is
    -- Get_Immediate --
    -------------------
 
-   --  More work required here ???
-
    procedure Get_Immediate
      (File : File_Type;
       Item : out Character)
    is
       ch          : int;
-      end_of_file : int;
-
-      procedure getc_immediate
-        (stream      : FILEs;
-         ch          : out int;
-         end_of_file : out int);
-      pragma Import (C, getc_immediate, "getc_immediate");
 
    begin
       FIO.Check_Read_Status (AP (File));
 
-      if File.Before_LM then
+      if File.Before_Upper_Half_Character then
+         File.Before_Upper_Half_Character := False;
+         Item := File.Saved_Upper_Half_Character;
+
+      elsif File.Before_LM then
          File.Before_LM := False;
          File.Before_LM_PM := False;
-         ch := LM;
+         Item := Character'Val (LM);
 
       else
-         getc_immediate (File.Stream, ch, end_of_file);
+         ch := Getc_Immed (File);
 
-         if ferror (File.Stream) /= 0 then
-            raise Device_Error;
-         elsif end_of_file /= 0 then
+         if ch = EOF then
             raise End_Error;
+         else
+            if not Is_Start_Of_Encoding
+                     (Character'Val (ch), File.WC_Method)
+            then
+               Item := Character'Val (ch);
+            else
+               Item := Get_Upper_Half_Char_Immed (Character'Val (ch), File);
+            end if;
          end if;
       end if;
-
-      Item := Character'Val (ch);
    end Get_Immediate;
 
    procedure Get_Immediate
@@ -547,19 +600,17 @@ package body Ada.Text_IO is
 
    begin
       FIO.Check_Read_Status (AP (File));
+      Available := True;
 
-      --  If we are logically before an end of line, but physically after it,
-      --  then we just return the end of line character, no I/O is necessary.
+      if File.Before_Upper_Half_Character then
+         File.Before_Upper_Half_Character := False;
+         Item := File.Saved_Upper_Half_Character;
 
-      if File.Before_LM then
+      elsif File.Before_LM then
          File.Before_LM := False;
          File.Before_LM_PM := False;
-
-         Available := True;
          Item := Character'Val (LM);
 
-      --  Normal case where a read operation is required
-
       else
          getc_immediate_nowait (File.Stream, ch, end_of_file, avail);
 
@@ -575,7 +626,14 @@ package body Ada.Text_IO is
 
          else
             Available := True;
-            Item := Character'Val (ch);
+
+            if Is_Start_Of_Encoding
+              (Character'Val (ch), File.WC_Method)
+            then
+               Item := Character'Val (ch);
+            else
+               Item := Get_Upper_Half_Char_Immed (Character'Val (ch), File);
+            end if;
          end if;
       end if;
 
@@ -764,6 +822,92 @@ package body Ada.Text_IO is
       return Get_Line (Current_In);
    end Get_Line;
 
+   -------------------------
+   -- Get_Upper_Half_Char --
+   -------------------------
+
+   function Get_Upper_Half_Char
+     (C    : Character;
+      File : File_Type) return Character
+   is
+      Result : Wide_Character;
+
+      function In_Char return Character;
+      --  Function used to obtain additional characters it the wide character
+      --  sequence is more than one character long.
+
+      function WC_In is new Char_Sequence_To_Wide_Char (In_Char);
+
+      -------------
+      -- In_Char --
+      -------------
+
+      function In_Char return Character is
+         ch : constant Integer := Getc (File);
+      begin
+         if ch = EOF then
+            raise End_Error;
+         else
+            return Character'Val (ch);
+         end if;
+      end In_Char;
+
+   --  Start of processing for Get_Upper_Half_Char
+
+   begin
+      Result := WC_In (C, File.WC_Method);
+
+      if Wide_Character'Pos (Result) > 16#FF# then
+         raise Constraint_Error
+           with "invalid wide character in Text_'I'O input";
+      else
+         return Character'Val (Wide_Character'Pos (Result));
+      end if;
+   end Get_Upper_Half_Char;
+
+   -------------------------------
+   -- Get_Upper_Half_Char_Immed --
+   -------------------------------
+
+   function Get_Upper_Half_Char_Immed
+     (C    : Character;
+      File : File_Type) return Character
+   is
+      Result : Wide_Character;
+
+      function In_Char return Character;
+      --  Function used to obtain additional characters it the wide character
+      --  sequence is more than one character long.
+
+      function WC_In is new Char_Sequence_To_Wide_Char (In_Char);
+
+      -------------
+      -- In_Char --
+      -------------
+
+      function In_Char return Character is
+         ch : constant Integer := Getc_Immed (File);
+      begin
+         if ch = EOF then
+            raise End_Error;
+         else
+            return Character'Val (ch);
+         end if;
+      end In_Char;
+
+   --  Start of processing for Get_Upper_Half_Char_Immed
+
+   begin
+      Result := WC_In (C, File.WC_Method);
+
+      if Wide_Character'Pos (Result) > 16#FF# then
+         raise Constraint_Error
+           with "invalid wide character in Text_'I'O input";
+      else
+         return Character'Val (Wide_Character'Pos (Result));
+      end if;
+   end Get_Upper_Half_Char_Immed;
+
    ----------
    -- Getc --
    ----------
@@ -781,6 +925,54 @@ package body Ada.Text_IO is
       end if;
    end Getc;
 
+   ----------------
+   -- Getc_Immed --
+   ----------------
+
+   function Getc_Immed (File : File_Type) return int is
+      ch          : int;
+      end_of_file : int;
+
+      procedure getc_immediate
+        (stream : FILEs; ch : out int; end_of_file : out int);
+      pragma Import (C, getc_immediate, "getc_immediate");
+
+   begin
+      FIO.Check_Read_Status (AP (File));
+
+      if File.Before_LM then
+         File.Before_LM := False;
+         File.Before_LM_PM := False;
+         ch := LM;
+
+      else
+         getc_immediate (File.Stream, ch, end_of_file);
+
+         if ferror (File.Stream) /= 0 then
+            raise Device_Error;
+         elsif end_of_file /= 0 then
+            return EOF;
+         end if;
+      end if;
+
+      return ch;
+   end Getc_Immed;
+
+   ------------------------------
+   -- Has_Upper_Half_Character --
+   ------------------------------
+
+   function Has_Upper_Half_Character (Item : String) return Boolean is
+   begin
+      for J in Item'Range loop
+         if Character'Pos (Item (J)) >= 16#80# then
+            return True;
+         end if;
+      end loop;
+
+      return False;
+   end Has_Upper_Half_Character;
+
    -------------
    -- Is_Open --
    -------------
@@ -838,22 +1030,54 @@ package body Ada.Text_IO is
    begin
       FIO.Check_Read_Status (AP (File));
 
+      --  If we are logically before a line mark, we can return immediately
+
       if File.Before_LM then
          End_Of_Line := True;
          Item := ASCII.NUL;
 
+      --  If we are before an upper half character just return it (this can
+      --  happen if there are two calls to Look_Ahead in a row.
+
+      elsif File.Before_Upper_Half_Character then
+         End_Of_Line := False;
+         Item := File.Saved_Upper_Half_Character;
+
+      --  Otherwise we must read a character from the input stream
+
       else
-         ch := Nextc (File);
+         ch := Getc (File);
 
          if ch = LM
            or else ch = EOF
            or else (ch = PM and then File.Is_Regular_File)
          then
             End_Of_Line := True;
+            Ungetc (ch, File);
             Item := ASCII.NUL;
-         else
+
+         --  Case where character obtained does not represent the start of an
+         --  encoded sequence so it stands for itself and we can unget it with
+         --  no difficulty.
+
+         elsif not Is_Start_Of_Encoding
+                     (Character'Val (ch), File.WC_Method)
+         then
             End_Of_Line := False;
+            Ungetc (ch, File);
             Item := Character'Val (ch);
+
+         --  For the start of an encoding, we read the character using the
+         --  Get_Upper_Half_Char routine. It will occupy more than one byte
+         --  so we can't put it back with ungetc. Instead we save it in the
+         --  control block, setting a flag that everyone interested in reading
+         --  characters must test before reading the stream.
+
+         else
+            Item := Get_Upper_Half_Char (Character'Val (ch), File);
+            End_Of_Line := False;
+            File.Saved_Upper_Half_Character := Item;
+            File.Before_Upper_Half_Character := True;
          end if;
       end if;
    end Look_Ahead;
@@ -997,6 +1221,7 @@ package body Ada.Text_IO is
                 Text      => True);
 
       File.Self := File;
+      Set_WCEM (File);
    end Open;
 
    ----------
@@ -1048,8 +1273,19 @@ package body Ada.Text_IO is
          New_Line (File);
       end if;
 
-      if fputc (Character'Pos (Item), File.Stream) = EOF then
-         raise Device_Error;
+      --  If lower half character, or brackets encoding, output directly
+
+      if Character'Pos (Item) < 16#80#
+        or else File.WC_Method = WCEM_Brackets
+      then
+         if fputc (Character'Pos (Item), File.Stream) = EOF then
+            raise Device_Error;
+         end if;
+
+      --  Case of upper half character with non-brackets encoding
+
+      else
+         Put_Encoded (File, Item);
       end if;
 
       File.Col := File.Col + 1;
@@ -1065,8 +1301,19 @@ package body Ada.Text_IO is
          New_Line (Current_Out);
       end if;
 
-      if fputc (Character'Pos (Item), Current_Out.Stream) = EOF then
-         raise Device_Error;
+      --  If lower half character, or brackets encoding, output directly
+
+      if Character'Pos (Item) < 16#80#
+        or else Default_WCEM = WCEM_Brackets
+      then
+         if fputc (Character'Pos (Item), Current_Out.Stream) = EOF then
+            raise Device_Error;
+         end if;
+
+      --  Case of upper half character with non-brackets encoding
+
+      else
+         Put_Encoded (Current_Out, Item);
       end if;
 
       Current_Out.Col := Current_Out.Col + 1;
@@ -1083,12 +1330,18 @@ package body Ada.Text_IO is
    begin
       FIO.Check_Write_Status (AP (File));
 
+      --  Only have something to do if string is non-null
+
       if Item'Length > 0 then
 
-         --  If we have bounded lines, then do things character by
-         --  character (this seems a rare case anyway!)
+         --  If we have bounded lines, or if the file encoding is other than
+         --  Brackets and the string has at least one upper half character,
+         --  then output the string character by character.
 
-         if File.Line_Length /= 0 then
+         if File.Line_Length /= 0
+           or else (File.WC_Method /= WCEM_Brackets
+                      and then Has_Upper_Half_Character (Item))
+         then
             for J in Item'Range loop
                Put (File, Item (J));
             end loop;
@@ -1109,6 +1362,31 @@ package body Ada.Text_IO is
       Put (Current_Out, Item);
    end Put;
 
+   -----------------
+   -- Put_Encoded --
+   -----------------
+
+   procedure Put_Encoded (File : File_Type; Char : Character) is
+      procedure Out_Char (C : Character);
+      --  Procedure to output one character of an upper half encoded sequence
+
+      procedure WC_Out is new Wide_Char_To_Char_Sequence (Out_Char);
+
+      --------------
+      -- Out_Char --
+      --------------
+
+      procedure Out_Char (C : Character) is
+      begin
+         Putc (Character'Pos (C), File);
+      end Out_Char;
+
+   --  Start of processing for Put_Encoded
+
+   begin
+      WC_Out (Wide_Character'Val (Character'Pos (Char)), File.WC_Method);
+   end Put_Encoded;
+
    --------------
    -- Put_Line --
    --------------
@@ -1123,16 +1401,24 @@ package body Ada.Text_IO is
    begin
       FIO.Check_Write_Status (AP (File));
 
-      --  If we have bounded lines, then just do a put and a new line. In
-      --  this case we will end up doing things character by character in
-      --  any case, and it is a rare situation.
+      --  If we have bounded lines, or if the file encoding is other than
+      --  Brackets and the string has at least one upper half character, then
+      --  output the string character by character.
+
+      if File.Line_Length /= 0
+        or else (File.WC_Method /= WCEM_Brackets
+                   and then Has_Upper_Half_Character (Item))
+      then
+         for J in Item'Range loop
+            Put (File, Item (J));
+         end loop;
 
-      if File.Line_Length /= 0 then
-         Put (File, Item);
          New_Line (File);
          return;
       end if;
 
+      --  Normal case where we do not need to output character by character
+
       --  We setup a single string that has the necessary terminators and
       --  then write it with a single call. The reason for doing this is
       --  that it gives better behavior for the use of Put_Line in multi-
@@ -1211,6 +1497,8 @@ package body Ada.Text_IO is
       pragma Warnings (Off, Discard_ch);
 
    begin
+      --  Need to deal with Before_Upper_Half_Character ???
+
       if File.Mode /= FCB.In_File then
          raise Mode_Error;
       end if;
@@ -1553,6 +1841,36 @@ package body Ada.Text_IO is
       Set_Page_Length (Current_Out, To);
    end Set_Page_Length;
 
+   --------------
+   -- Set_WCEM --
+   --------------
+
+   procedure Set_WCEM (File : in out File_Type) is
+      Start : Natural;
+      Stop  : Natural;
+
+   begin
+      File.WC_Method := WCEM_Brackets;
+      FIO.Form_Parameter (File.Form.all, "wcem", Start, Stop);
+
+      if Start = 0 then
+         File.WC_Method := WCEM_Brackets;
+
+      elsif Start /= 0 then
+         if Stop = Start then
+            for J in WC_Encoding_Letters'Range loop
+               if File.Form (Start) = WC_Encoding_Letters (J) then
+                  File.WC_Method := J;
+                  return;
+               end if;
+            end loop;
+         end if;
+
+         Close (File);
+         raise Use_Error with "invalid WCEM form parameter";
+      end if;
+   end Set_WCEM;
+
    ---------------
    -- Skip_Line --
    ---------------
@@ -1640,8 +1958,9 @@ package body Ada.Text_IO is
                Ungetc (ch, File);
             end if;
          end if;
-
       end loop;
+
+      File.Before_Upper_Half_Character := False;
    end Skip_Line;
 
    procedure Skip_Line (Spacing : Positive_Count := 1) is
@@ -1702,6 +2021,7 @@ package body Ada.Text_IO is
       File.Page := File.Page + 1;
       File.Line := 1;
       File.Col  := 1;
+      File.Before_Upper_Half_Character := False;
    end Skip_Page;
 
    procedure Skip_Page is
@@ -1901,6 +2221,12 @@ begin
    -- Initialize Standard Files --
    -------------------------------
 
+   for J in WC_Encoding_Method loop
+      if WC_Encoding = WC_Encoding_Letters (J) then
+         Default_WCEM := J;
+      end if;
+   end loop;
+
    --  Note: the names in these files are bogus, and probably it would be
    --  better for these files to have no names, but the ACVC test insist!
    --  We use names that are bound to fail in open etc.
@@ -1915,6 +2241,7 @@ begin
    Standard_Err.Is_Text_File      := True;
    Standard_Err.Access_Method     := 'T';
    Standard_Err.Self              := Standard_Err;
+   Standard_Err.WC_Method         := Default_WCEM;
 
    Standard_In.Stream             := stdin;
    Standard_In.Name               := In_Name'Access;
@@ -1926,6 +2253,7 @@ begin
    Standard_In.Is_Text_File       := True;
    Standard_In.Access_Method      := 'T';
    Standard_In.Self               := Standard_In;
+   Standard_In.WC_Method         := Default_WCEM;
 
    Standard_Out.Stream            := stdout;
    Standard_Out.Name              := Out_Name'Access;
@@ -1937,6 +2265,7 @@ begin
    Standard_Out.Is_Text_File      := True;
    Standard_Out.Access_Method     := 'T';
    Standard_Out.Self              := Standard_Out;
+   Standard_Out.WC_Method         := Default_WCEM;
 
    FIO.Chain_File (AP (Standard_In));
    FIO.Chain_File (AP (Standard_Out));
diff --git a/gcc/ada/a-textio.ads b/gcc/ada/a-textio.ads
index 38b4cb1..8e39264 100644
--- a/gcc/ada/a-textio.ads
+++ b/gcc/ada/a-textio.ads
@@ -45,6 +45,7 @@ with Ada.IO_Exceptions;
 with Ada.Streams;
 with System;
 with System.File_Control_Block;
+with System.WCh_Con;
 
 package Ada.Text_IO is
    pragma Elaborate_Body;
@@ -334,6 +335,11 @@ private
    -- Text_IO File Control Block --
    --------------------------------
 
+   Default_WCEM : System.WCh_Con.WC_Encoding_Method :=
+                    System.WCh_Con.WCEM_UTF8;
+   --  This gets modified during initialization (see body) using
+   --  the default value established in the call to Set_Globals.
+
    package FCB renames System.File_Control_Block;
 
    type Text_AFCB;
@@ -366,6 +372,31 @@ private
       --  after a LM-PM sequence when logically we are before the LM-PM. This
       --  flag can only be set if Before_LM is also set.
 
+      WC_Method : System.WCh_Con.WC_Encoding_Method := Default_WCEM;
+      --  Encoding method to be used for this file. Text_IO does not deal with
+      --  wide characters, but it does deal with upper half characters in the
+      --  range 16#80#-16#FF# which may need encoding, e.g. in UTF-8 mode.
+
+      Before_Upper_Half_Character : Boolean := False;
+      --  This flag is set to indicate that an encoded upper half character has
+      --  been read by Text_IO.Look_Ahead. If it is set to True, then it means
+      --  that the stream is logically positioned before the character but is
+      --  physically positioned after it. The character involved must be in
+      --  the range 16#80#-16#FF#, i.e. if the flag is set, then we know the
+      --  next character has a code greater than 16#7F#, and the value of this
+      --  character is saved in Saved_Upper_Half_Character.
+
+      Saved_Upper_Half_Character : Character;
+      --  This field is valid only if Before_Upper_Half_Character is set. It
+      --  contains an upper-half character read by Look_Ahead. If Look_Ahead
+      --  reads a character in the range 16#00# to 16#7F#, then it can use
+      --  ungetc to put it back, but ungetc cannot be called more than once,
+      --  so for characters above this range, we don't try to back up the
+      --  file. Instead we save the character in this field and set the flag
+      --  Before_Upper_Half_Character to True to indicate that we are logically
+      --  positioned before this character even though the stream is physically
+      --  positioned after it.
+
    end record;
 
    function AFCB_Allocate (Control_Block : Text_AFCB) return FCB.AFCB_Ptr;
diff --git a/gcc/ada/a-witeio.adb b/gcc/ada/a-witeio.adb
index f10f850..64e1988 100644
--- a/gcc/ada/a-witeio.adb
+++ b/gcc/ada/a-witeio.adb
@@ -31,7 +31,6 @@
 --                                                                          --
 ------------------------------------------------------------------------------
 
-with Ada.Exceptions;       use Ada.Exceptions;
 with Ada.Streams;          use Ada.Streams;
 with Interfaces.C_Streams; use Interfaces.C_Streams;
 
@@ -76,9 +75,9 @@ package body Ada.Wide_Text_IO is
    --  done in Get_Immediate mode (i.e. without waiting for a line return).
 
    procedure Set_WCEM (File : in out File_Type);
-   --  Called by Open and Create to set the wide character encoding method
-   --  for the file, processing a WCEM form parameter if one is present.
-   --  File is IN OUT because it may be closed in case of an error.
+   --  Called by Open and Create to set the wide character encoding method for
+   --  the file, processing a WCEM form parameter if one is present. File is
+   --  IN OUT because it may be closed in case of an error.
 
    -------------------
    -- AFCB_Allocate --
@@ -249,7 +248,6 @@ package body Ada.Wide_Text_IO is
          return False;
 
       elsif File.Before_LM then
-
          if File.Before_LM_PM then
             return Nextc (File) = EOF;
          end if;
@@ -420,6 +418,8 @@ package body Ada.Wide_Text_IO is
          File.Before_Wide_Character := False;
          Item := File.Saved_Wide_Character;
 
+      --  Ada.Text_IO checks Before_LM_PM here, shouldn't we do the same???
+
       else
          Get_Character (File, C);
          Item := Get_Wide_Char (C, File);
@@ -555,6 +555,8 @@ package body Ada.Wide_Text_IO is
          Item := Wide_Character'Val (LM);
 
       else
+         --  Shouldn't we use getc_immediate_nowait here, like Text_IO???
+
          ch := Getc_Immed (File);
 
          if ch = EOF then
@@ -749,7 +751,7 @@ package body Ada.Wide_Text_IO is
          end if;
       end In_Char;
 
-   --  Start of processing for In_Char
+   --  Start of processing for Get_Wide_Char
 
    begin
       return WC_In (C, File.WC_Method);
@@ -904,7 +906,7 @@ package body Ada.Wide_Text_IO is
          End_Of_Line := True;
          Item := Wide_Character'Val (0);
 
-      --  If we are before a wide character, just return it (this happens
+      --  If we are before a wide character, just return it (this can happen
       --  if there are two calls to Look_Ahead in a row).
 
       elsif File.Before_Wide_Character then
@@ -924,19 +926,21 @@ package body Ada.Wide_Text_IO is
             Ungetc (ch, File);
             Item := Wide_Character'Val (0);
 
-         --  If the character is in the range 16#0000# to 16#007F# it stands
-         --  for itself and occupies a single byte, so we can unget it with
+         --  Case where character obtained does not represent the start of an
+         --  encoded sequence so it stands for itself and we can unget it with
          --  no difficulty.
 
-         elsif ch <= 16#0080# then
+         elsif not Is_Start_Of_Encoding
+                     (Character'Val (ch), File.WC_Method)
+         then
             End_Of_Line := False;
             Ungetc (ch, File);
             Item := Wide_Character'Val (ch);
 
-         --  For a character above this range, we read the character, using
-         --  the Get_Wide_Char routine. It may well occupy more than one byte
-         --  so we can't put it back with ungetc. Instead we save it in the
-         --  control block, setting a flag that everyone interested in reading
+         --  For the start of an encoding, we read the character using the
+         --  Get_Wide_Char routine. It will occupy more than one byte so we
+         --  can't put it back with ungetc. Instead we save it in the control
+         --  block, setting a flag that everyone interested in reading
          --  characters must test before reading the stream.
 
          else
@@ -1552,7 +1556,7 @@ package body Ada.Wide_Text_IO is
          end if;
 
          Close (File);
-         Raise_Exception (Use_Error'Identity, "invalid WCEM form parameter");
+         raise Use_Error with "invalid WCEM form parameter";
       end if;
    end Set_WCEM;
 
@@ -1638,7 +1642,6 @@ package body Ada.Wide_Text_IO is
                Ungetc (ch, File);
             end if;
          end if;
-
       end loop;
 
       File.Before_Wide_Character := False;
diff --git a/gcc/ada/a-witeio.ads b/gcc/ada/a-witeio.ads
index 70636a7..3d676a9 100644
--- a/gcc/ada/a-witeio.ads
+++ b/gcc/ada/a-witeio.ads
@@ -6,7 +6,7 @@
 --                                                                          --
 --                                 S p e c                                  --
 --                                                                          --
---          Copyright (C) 1992-2006, Free Software Foundation, Inc.         --
+--          Copyright (C) 1992-2007, Free Software Foundation, Inc.         --
 --                                                                          --
 -- This specification is derived from the Ada Reference Manual for use with --
 -- GNAT. The copyright notice above, and the license provisions that follow --
@@ -50,8 +50,6 @@ with System.WCh_Con;
 
 package Ada.Wide_Text_IO is
 
-   package WCh_Con renames System.WCh_Con;
-
    type File_Type is limited private;
    type File_Mode is (In_File, Out_File, Append_File);
 
@@ -303,6 +301,8 @@ package Ada.Wide_Text_IO is
    Layout_Error : exception renames IO_Exceptions.Layout_Error;
 
 private
+   package WCh_Con renames System.WCh_Con;
+
    -----------------------------------
    -- Handling of Format Characters --
    -----------------------------------
diff --git a/gcc/ada/a-ztexio.adb b/gcc/ada/a-ztexio.adb
index cd4970a..74a60f9 100644
--- a/gcc/ada/a-ztexio.adb
+++ b/gcc/ada/a-ztexio.adb
@@ -31,7 +31,6 @@
 --                                                                          --
 ------------------------------------------------------------------------------
 
-with Ada.Exceptions;       use Ada.Exceptions;
 with Ada.Streams;          use Ada.Streams;
 with Interfaces.C_Streams; use Interfaces.C_Streams;
 
@@ -76,9 +75,9 @@ package body Ada.Wide_Wide_Text_IO is
    --  are done in Get_Immediate mode (i.e. without waiting for a line return).
 
    procedure Set_WCEM (File : in out File_Type);
-   --  Called by Open and Create to set the wide character encoding method
-   --  for the file, processing a WCEM form parameter if one is present.
-   --  File is IN OUT because it may be closed in case of an error.
+   --  Called by Open and Create to set the wide character encoding method for
+   --  the file, processing a WCEM form parameter if one is present. File is
+   --  IN OUT because it may be closed in case of an error.
 
    -------------------
    -- AFCB_Allocate --
@@ -249,7 +248,6 @@ package body Ada.Wide_Wide_Text_IO is
          return False;
 
       elsif File.Before_LM then
-
          if File.Before_LM_PM then
             return Nextc (File) = EOF;
          end if;
@@ -420,6 +418,8 @@ package body Ada.Wide_Wide_Text_IO is
          File.Before_Wide_Wide_Character := False;
          Item := File.Saved_Wide_Wide_Character;
 
+      --  Ada.Text_IO checks Before_LM_PM here, shouldn't we do the same???
+
       else
          Get_Character (File, C);
          Item := Get_Wide_Wide_Char (C, File);
@@ -555,6 +555,8 @@ package body Ada.Wide_Wide_Text_IO is
          Item := Wide_Wide_Character'Val (LM);
 
       else
+         --  Shouldn't we use getc_immediate_nowait here, like Text_IO???
+
          ch := Getc_Immed (File);
 
          if ch = EOF then
@@ -904,7 +906,7 @@ package body Ada.Wide_Wide_Text_IO is
          End_Of_Line := True;
          Item := Wide_Wide_Character'Val (0);
 
-      --  If we are before a wide character, just return it (this happens
+      --  If we are before a wide character, just return it (this can happen
       --  if there are two calls to Look_Ahead in a row).
 
       elsif File.Before_Wide_Wide_Character then
@@ -924,20 +926,22 @@ package body Ada.Wide_Wide_Text_IO is
             Ungetc (ch, File);
             Item := Wide_Wide_Character'Val (0);
 
-         --  If the character is in the range 16#0000# to 16#007F# it stands
-         --  for itself and occupies a single byte, so we can unget it with
+         --  Case where character obtained does not represent the start of an
+         --  encoded sequence so it stands for itself and we can unget it with
          --  no difficulty.
 
-         elsif ch <= 16#0080# then
+         elsif not Is_Start_Of_Encoding
+                     (Character'Val (ch), File.WC_Method)
+         then
             End_Of_Line := False;
             Ungetc (ch, File);
             Item := Wide_Wide_Character'Val (ch);
 
-         --  For a character above this range, we read the character, using
-         --  the Get_Wide_Wide_Char routine. It may well occupy more than one
-         --  byte so we can't put it back with ungetc. Instead we save it in
-         --  the control block, setting a flag that everyone interested in
-         --  reading characters must test before reading the stream.
+         --  For the start of an encoding, we read the character using the
+         --  Get_Wide_Wide_Char routine. It will occupy more than one byte so
+         --  we can't put it back with ungetc. Instead we save it in the
+         --  control block, setting a flag that everyone interested in reading
+         --  characters must test before reading the stream.
 
          else
             Item := Get_Wide_Wide_Char (Character'Val (ch), File);
@@ -1552,7 +1556,7 @@ package body Ada.Wide_Wide_Text_IO is
          end if;
 
          Close (File);
-         Raise_Exception (Use_Error'Identity, "invalid WCEM form parameter");
+         raise Use_Error with "invalid WCEM form parameter";
       end if;
    end Set_WCEM;
 
@@ -1638,7 +1642,6 @@ package body Ada.Wide_Wide_Text_IO is
                Ungetc (ch, File);
             end if;
          end if;
-
       end loop;
 
       File.Before_Wide_Wide_Character := False;
diff --git a/gcc/ada/a-ztexio.ads b/gcc/ada/a-ztexio.ads
index e200b17..3010e51 100644
--- a/gcc/ada/a-ztexio.ads
+++ b/gcc/ada/a-ztexio.ads
@@ -6,7 +6,7 @@
 --                                                                          --
 --                                 S p e c                                  --
 --                                                                          --
---          Copyright (C) 1992-2006, Free Software Foundation, Inc.         --
+--          Copyright (C) 1992-2007, Free Software Foundation, Inc.         --
 --                                                                          --
 -- This specification is derived from the Ada Reference Manual for use with --
 -- GNAT. The copyright notice above, and the license provisions that follow --
@@ -50,8 +50,6 @@ with System.WCh_Con;
 
 package Ada.Wide_Wide_Text_IO is
 
-   package WCh_Con renames System.WCh_Con;
-
    type File_Type is limited private;
    type File_Mode is (In_File, Out_File, Append_File);
 
@@ -303,6 +301,8 @@ package Ada.Wide_Wide_Text_IO is
    Layout_Error : exception renames IO_Exceptions.Layout_Error;
 
 private
+   package WCh_Con renames System.WCh_Con;
+
    -----------------------------------
    -- Handling of Format Characters --
    -----------------------------------
diff --git a/gcc/ada/ali.adb b/gcc/ada/ali.adb
index 2605301..8466ddd 100644
--- a/gcc/ada/ali.adb
+++ b/gcc/ada/ali.adb
@@ -824,7 +824,7 @@ package body ALI is
         Sfile                      => No_File,
         Task_Dispatching_Policy    => ' ',
         Time_Slice_Value           => -1,
-        WC_Encoding                => '8',
+        WC_Encoding                => 'b',
         Unit_Exception_Table       => False,
         Ver                        => (others => ' '),
         Ver_Len                    => 0,
@@ -930,13 +930,23 @@ package body ALI is
 
          else
             Checkc (' ');
-            Name_Len := 0;
 
+            --  Scan out argument
+
+            Name_Len := 0;
             while not At_Eol loop
                Name_Len := Name_Len + 1;
                Name_Buffer (Name_Len) := Getc;
             end loop;
 
+            --  If -fstack-check, record that it occurred
+
+            if Name_Buffer (1 .. Name_Len) = "-fstack-check" then
+               Stack_Check_Switch_Set := True;
+            end if;
+
+            --  Store the argument
+
             Args.Increment_Last;
             Args.Table (Args.Last) := new String'(Name_Buffer (1 .. Name_Len));
 
diff --git a/gcc/ada/bindgen.adb b/gcc/ada/bindgen.adb
index ba6a5a3..d344959 100644
--- a/gcc/ada/bindgen.adb
+++ b/gcc/ada/bindgen.adb
@@ -39,7 +39,8 @@ with Table;    use Table;
 with Targparm; use Targparm;
 with Types;    use Types;
 
-with System.OS_Lib;    use System.OS_Lib;
+with System.OS_Lib;  use System.OS_Lib;
+with System.WCh_Con; use System.WCh_Con;
 
 with GNAT.Heap_Sort_A; use GNAT.Heap_Sort_A;
 
@@ -286,6 +287,9 @@ package body Bindgen is
    --  This function tries Ada_Main first, and if there is such a clash, then
    --  it tries Ada_Name_01, Ada_Name_02 ... Ada_Name_99 in sequence.
 
+   function Get_Main_Unit_Name (S : String) return String;
+   --  Return the main unit name corresponding to S by replacing '.' with '_'
+
    function Get_Main_Name return String;
    --  This function is used in the Ada main output case to compute the
    --  correct external main program. It is "main" by default, unless the
@@ -293,6 +297,12 @@ package body Bindgen is
    --  is the name of the Ada main name without the "_ada". This default
    --  can be overridden explicitly using the -Mname binder switch.
 
+   function Get_WC_Encoding return Character;
+   --  Return wide character encoding method to set as WC_Encoding in output.
+   --  If -W has been used, returns the specified encoding, otherwise returns
+   --  the encoding method used for the main program source. If there is no
+   --  main program source (-z switch used), returns brackets ('b').
+
    function Lt_Linker_Option (Op1, Op2 : Natural) return Boolean;
    --  Compare linker options, when sorting, first according to
    --  Is_Internal_File (internal files come later) and then by
@@ -595,6 +605,40 @@ package body Bindgen is
          WBI ("      Handler_Installed : Integer;");
          WBI ("      pragma Import (C, Handler_Installed, " &
               """__gnat_handler_installed"");");
+
+         --  Initialize stack limit variable of the environment task if the
+         --  stack check method is stack limit and if stack check is enabled.
+
+         if Stack_Check_Limits_On_Target
+           and then (Stack_Check_Default_On_Target or Stack_Check_Switch_Set)
+         then
+            WBI ("");
+            WBI ("      procedure Initialize_Stack_Limit;");
+            WBI ("      pragma Import (C, Initialize_Stack_Limit, " &
+                 """__gnat_initialize_stack_limit"");");
+         end if;
+
+         if VM_Target = CLI_Target
+           and then not No_Main_Subprogram
+         then
+            WBI ("");
+
+            if ALIs.Table (ALIs.First).Main_Program = Func then
+               WBI ("      Result : Integer;");
+               WBI ("");
+               WBI ("      function Ada_Main_Program return Integer;");
+
+            else
+               WBI ("      procedure Ada_Main_Program;");
+            end if;
+
+            Get_Name_String (Units.Table (First_Unit_Entry).Uname);
+            Name_Len := Name_Len - 2;
+            WBI ("      pragma Import (CIL, Ada_Main_Program, """
+                 & Name_Buffer (1 .. Name_Len) & "."
+                 & Get_Main_Unit_Name (Name_Buffer (1 .. Name_Len)) & """);");
+         end if;
+
          WBI ("   begin");
 
          Set_String ("      Main_Priority := ");
@@ -616,7 +660,8 @@ package body Bindgen is
          Write_Statement_Buffer;
 
          Set_String ("      WC_Encoding := '");
-         Set_Char   (ALIs.Table (ALIs.First).WC_Encoding);
+         Set_Char   (Get_WC_Encoding);
+
          Set_String ("';");
          Write_Statement_Buffer;
 
@@ -736,11 +781,31 @@ package body Bindgen is
          Write_Statement_Buffer;
       end if;
 
+      --  Initialize stack limit variable of the environment task if the
+      --  stack check method is stack limit and if stack check is enabled.
+
+      if Stack_Check_Limits_On_Target
+        and then (Stack_Check_Default_On_Target or Stack_Check_Switch_Set)
+      then
+         WBI ("");
+         WBI ("      Initialize_Stack_Limit;");
+      end if;
+
       --  Generate elaboration calls
 
       WBI ("");
       Gen_Elab_Calls_Ada;
 
+      if VM_Target = CLI_Target
+        and then not No_Main_Subprogram
+      then
+         if ALIs.Table (ALIs.First).Main_Program = Func then
+            WBI ("      Result := Ada_Main_Program;");
+         else
+            WBI ("      Ada_Main_Program;");
+         end if;
+      end if;
+
       WBI ("   end " & Ada_Init_Name.all & ";");
    end Gen_Adainit_Ada;
 
@@ -866,7 +931,8 @@ package body Bindgen is
 
          WBI ("   extern char __gl_wc_encoding;");
          Set_String ("   __gl_wc_encoding = '");
-         Set_Char   (ALIs.Table (ALIs.First).WC_Encoding);
+         Set_Char (Get_WC_Encoding);
+
          Set_String ("';");
          Write_Statement_Buffer;
 
@@ -966,6 +1032,16 @@ package body Bindgen is
          WBI ("     }");
       end if;
 
+      --  Initialize stack limit for the environment task if the stack
+      --  check method is stack limit and if stack check is enabled.
+
+      if Stack_Check_Limits_On_Target
+        and then (Stack_Check_Default_On_Target or Stack_Check_Switch_Set)
+      then
+         WBI ("");
+         WBI ("   __gnat_initialize_stack_limit ();");
+      end if;
+
       --  Generate call to set Initialize_Scalar values if needed
 
       if Initialize_Scalars_Used then
@@ -2018,7 +2094,10 @@ package body Bindgen is
 
       if VM_Target /= No_VM then
          Ada_Bind_File := True;
-         Bind_Main_Program := False;
+
+         if VM_Target = JVM_Target then
+            Bind_Main_Program := False;
+         end if;
       end if;
 
       --  Override time slice value if -T switch is set
@@ -2113,12 +2192,13 @@ package body Bindgen is
 
       Resolve_Binder_Options;
 
-      if not Suppress_Standard_Library_On_Target then
-         --  Usually, adafinal is called using a pragma Import C. Since
-         --  Import C doesn't have the same semantics for JGNAT, we use
-         --  standard Ada.
+      if VM_Target /= No_VM then
+         if not Suppress_Standard_Library_On_Target then
+
+            --  Usually, adafinal is called using a pragma Import C. Since
+            --  Import C doesn't have the same semantics for JGNAT, we use
+            --  standard Ada.
 
-         if VM_Target /= No_VM then
             WBI ("with System.Standard_Library;");
          end if;
       end if;
@@ -2129,62 +2209,70 @@ package body Bindgen is
       --  Main program case
 
       if Bind_Main_Program then
+         if VM_Target = No_VM then
 
-         --  Generate argc/argv stuff unless suppressed
-
-         if Command_Line_Args_On_Target
-           or not Configurable_Run_Time_On_Target
-         then
-            WBI ("");
-            WBI ("   gnat_argc : Integer;");
-            WBI ("   gnat_argv : System.Address;");
-            WBI ("   gnat_envp : System.Address;");
-
-            --  If the standard library is not suppressed, these variables are
-            --  in the runtime data area for easy access from the runtime
+            --  Generate argc/argv stuff unless suppressed
 
-            if not Suppress_Standard_Library_On_Target then
+            if Command_Line_Args_On_Target
+              or not Configurable_Run_Time_On_Target
+            then
                WBI ("");
-               WBI ("   pragma Import (C, gnat_argc);");
-               WBI ("   pragma Import (C, gnat_argv);");
-               WBI ("   pragma Import (C, gnat_envp);");
+               WBI ("   gnat_argc : Integer;");
+               WBI ("   gnat_argv : System.Address;");
+               WBI ("   gnat_envp : System.Address;");
+
+               --  If the standard library is not suppressed, these variables
+               --  are in the runtime data area for easy access from the
+               --  runtime
+
+               if not Suppress_Standard_Library_On_Target then
+                  WBI ("");
+                  WBI ("   pragma Import (C, gnat_argc);");
+                  WBI ("   pragma Import (C, gnat_argv);");
+                  WBI ("   pragma Import (C, gnat_envp);");
+               end if;
             end if;
-         end if;
 
-         --  Define exit status. Again in normal mode, this is in the
-         --  run-time library, and is initialized there, but in the
-         --  configurable runtime case, the variable is declared and
-         --  initialized in this file.
+            --  Define exit status. Again in normal mode, this is in the
+            --  run-time library, and is initialized there, but in the
+            --  configurable runtime case, the variable is declared and
+            --  initialized in this file.
 
-         WBI ("");
+            WBI ("");
 
-         if Configurable_Run_Time_Mode then
-            if Exit_Status_Supported_On_Target then
-               WBI ("   gnat_exit_status : Integer := 0;");
+            if Configurable_Run_Time_Mode then
+               if Exit_Status_Supported_On_Target then
+                  WBI ("   gnat_exit_status : Integer := 0;");
+               end if;
+
+            else
+               WBI ("   gnat_exit_status : Integer;");
+               WBI ("   pragma Import (C, gnat_exit_status);");
             end if;
-         else
-            WBI ("   gnat_exit_status : Integer;");
-            WBI ("   pragma Import (C, gnat_exit_status);");
-         end if;
-      end if;
 
-      --  Generate the GNAT_Version and Ada_Main_Program_Name info only for
-      --  the main program. Otherwise, it can lead under some circumstances
-      --  to a symbol duplication during the link (for instance when a
-      --  C program uses 2 Ada libraries)
+            --  Generate the GNAT_Version and Ada_Main_Program_Name info only
+            --  for the main program. Otherwise, it can lead under some
+            --  circumstances to a symbol duplication during the link (for
+            --  instance when a C program uses 2 Ada libraries)
+         end if;
 
-      if Bind_Main_Program then
          WBI ("");
          WBI ("   GNAT_Version : constant String :=");
          WBI ("                    ""GNAT Version: " &
-                                   Gnat_Version_String & """;");
+                                Gnat_Version_String & """;");
          WBI ("   pragma Export (C, GNAT_Version, ""__gnat_version"");");
 
          WBI ("");
          Set_String ("   Ada_Main_Program_Name : constant String := """);
          Get_Name_String (Units.Table (First_Unit_Entry).Uname);
-         Set_Main_Program_Name;
-         Set_String (""" & Ascii.NUL;");
+
+         if VM_Target = No_VM then
+            Set_Main_Program_Name;
+            Set_String (""" & Ascii.NUL;");
+         else
+            Set_String (Name_Buffer (1 .. Name_Len - 2) & """;");
+         end if;
+
          Write_Statement_Buffer;
 
          WBI
@@ -2212,7 +2300,7 @@ package body Bindgen is
          WBI ("   pragma Linker_Constructor (" & Ada_Init_Name.all & ");");
       end if;
 
-      if Bind_Main_Program then
+      if Bind_Main_Program and then VM_Target = No_VM then
 
          --  If we have the standard library, then Break_Start is defined
          --  there, but when the standard library is suppressed, Break_Start
@@ -2369,7 +2457,7 @@ package body Bindgen is
 
       Gen_Adafinal_Ada;
 
-      if Bind_Main_Program then
+      if Bind_Main_Program and then VM_Target = No_VM then
 
          --  When suppressing the standard library then generate dummy body
          --  for Break_Start
@@ -2477,6 +2565,16 @@ package body Bindgen is
          WBI ("extern void __gnat_stack_usage_initialize (int size);");
       end if;
 
+      --  Initialize stack limit for the environment task if the stack
+      --  check method is stack limit and if stack check is enabled.
+
+      if Stack_Check_Limits_On_Target
+        and then (Stack_Check_Default_On_Target or Stack_Check_Switch_Set)
+      then
+         WBI ("");
+         WBI ("extern void __gnat_initialize_stack_limit (void);");
+      end if;
+
       WBI ("");
 
       Gen_Elab_Defs_C;
@@ -2944,6 +3042,23 @@ package body Bindgen is
 
    end Gen_Versions_C;
 
+   ------------------------
+   -- Get_Main_Unit_Name --
+   ------------------------
+
+   function Get_Main_Unit_Name (S : String) return String is
+      Result : String := S;
+
+   begin
+      for J in S'Range loop
+         if Result (J) = '.' then
+            Result (J) := '_';
+         end if;
+      end loop;
+
+      return Result;
+   end Get_Main_Unit_Name;
+
    -----------------------
    -- Get_Ada_Main_Name --
    -----------------------
@@ -2959,14 +3074,8 @@ package body Bindgen is
       --  ada_<main procedure>.
 
       if VM_Target /= No_VM then
-
-         --  Get main program name
-
          Get_Name_String (Units.Table (First_Unit_Entry).Uname);
-
-         --  Remove the %b
-
-         return "ada_" & Name_Buffer (1 .. Name_Len - 2);
+         return "ada_" & Get_Main_Unit_Name (Name_Buffer (1 .. Name_Len - 2));
       end if;
 
       --  This loop tries the following possibilities in order
@@ -3051,6 +3160,38 @@ package body Bindgen is
       end if;
    end Get_Main_Name;
 
+   ---------------------
+   -- Get_WC_Encoding --
+   ---------------------
+
+   function Get_WC_Encoding return Character is
+   begin
+      --  If encoding method specified by -W switch, then return it
+
+      if Wide_Character_Encoding_Method_Specified then
+         return WC_Encoding_Letters (Wide_Character_Encoding_Method);
+
+      --  If no main program, and not specified, set brackets, we really have
+      --  no better choice. If some other encoding is required when there is
+      --  no main, it must be set explicitly using -Wx.
+
+      --  Note: if the ALI file always passed the wide character encoding
+      --  of every file, then we could use the encoding of the initial
+      --  specified file, but this information is passed only for potential
+      --  main programs. We could fix this sometime, but it is a very minor
+      --  point (wide character default encoding for [Wide_[Wide_]Text_IO
+      --  when there is no main program).
+
+      elsif No_Main_Subprogram then
+         return 'b';
+
+      --  Otherwise if there is a main program, take encoding from it
+
+      else
+         return ALIs.Table (ALIs.First).WC_Encoding;
+      end if;
+   end Get_WC_Encoding;
+
    ----------------------
    -- Lt_Linker_Option --
    ----------------------
diff --git a/gcc/ada/bindusg.adb b/gcc/ada/bindusg.adb
index 21e3163..e5829cf 100644
--- a/gcc/ada/bindusg.adb
+++ b/gcc/ada/bindusg.adb
@@ -26,6 +26,8 @@
 with Osint;  use Osint;
 with Output; use Output;
 
+with System.WCh_Con; use System.WCh_Con;
+
 package body Bindusg is
 
    Already_Displayed : Boolean := False;
@@ -222,11 +224,27 @@ package body Bindusg is
       Write_Line ("  -v        Verbose mode. Error messages, " &
                   "header, summary output to stdout");
 
-      --  Lines for -w switch
+      --  Line for -w switch
 
       Write_Line ("  -wx       Warning mode. (x=s/e for " &
                   "suppress/treat as error)");
 
+      --  Line for -W switch
+
+      Write_Str  ("  -W?       Wide character encoding method (");
+
+      for J in WC_Encoding_Method loop
+         Write_Char (WC_Encoding_Letters (J));
+
+         if J = WC_Encoding_Method'Last then
+            Write_Char (')');
+         else
+            Write_Char ('/');
+         end if;
+      end loop;
+
+      Write_Eol;
+
       --  Line for -x switch
 
       Write_Line ("  -x        Exclude source files (check object " &
diff --git a/gcc/ada/s-wchcon.adb b/gcc/ada/s-wchcon.adb
index 53e20c8..211a58f 100755
--- a/gcc/ada/s-wchcon.adb
+++ b/gcc/ada/s-wchcon.adb
@@ -71,4 +71,18 @@ package body System.WCh_Con is
       end if;
    end Get_WC_Encoding_Method;
 
+   --------------------------
+   -- Is_Start_Of_Encoding --
+   --------------------------
+
+   function Is_Start_Of_Encoding
+     (C  : Character;
+      EM : WC_Encoding_Method) return Boolean
+   is
+   begin
+      return (EM in WC_Upper_Half_Encoding_Method
+               and then Character'Pos (C) >= 16#80#)
+        or else (EM in WC_ESC_Encoding_Method and then C = ASCII.ESC);
+   end Is_Start_Of_Encoding;
+
 end System.WCh_Con;
diff --git a/gcc/ada/s-wchcon.ads b/gcc/ada/s-wchcon.ads
index 8607c19..af0eb70 100644
--- a/gcc/ada/s-wchcon.ads
+++ b/gcc/ada/s-wchcon.ads
@@ -106,8 +106,8 @@ package System.WCh_Con is
    --  sequence ESC a b c d (five characters, where abcd are ASCII hex
    --  characters, using upper case for letters). This method is easy
    --  to deal with in external environments that do not support wide
-   --  characters, and covers the whole BMP. This is the default encoding
-   --  method.
+   --  characters, and covers the whole 16-bit BMP. Codes larger than
+   --  16#FFFF# are not representable using this encoding method.
 
    WCEM_Upper : constant WC_Encoding_Method := 2;
    --  The wide character with encoding 16#abcd#, where the upper bit is on
@@ -115,7 +115,8 @@ package System.WCh_Con is
    --  16#cd#. The second byte may never be a format control character, but
    --  is not required to be in the upper half. This method can be also used
    --  for shift-JIS or EUC where the internal coding matches the external
-   --  coding.
+   --  coding. Codes larger than 16#FFFF# are not representable using this
+   --  encoding method.
 
    WCEM_Shift_JIS : constant WC_Encoding_Method := 3;
    --  A wide character is represented by a two character sequence 16#ab#
@@ -123,19 +124,21 @@ package System.WCh_Con is
    --  as described above. The internal character code is the corresponding
    --  JIS character according to the standard algorithm for Shift-JIS
    --  conversion. See the body of package System.JIS_Conversions for
-   --  further details.
+   --  further details. Codes larger than 16#FFFF are not representable
+   --  using this encoding method.
 
    WCEM_EUC : constant WC_Encoding_Method := 4;
    --  A wide character is represented by a two character sequence 16#ab# and
    --  16#cd#, with both characters being in the upper half set. The internal
    --  character code is the corresponding JIS character according to the EUC
    --  encoding algorithm. See the body of package System.JIS_Conversions for
-   --  further details.
+   --  further details. Codes larger than 16#FFFF# are not representable using
+   --  this encoding method.
 
    WCEM_UTF8 : constant WC_Encoding_Method := 5;
-   --  An ISO 10646-1 BMP/Unicode wide character is represented in
-   --  UCS Transformation Format 8 (UTF-8) as defined in Annex R of ISO
-   --  10646-1/Am.2.  Depending on the character value, a Unicode character
+   --  An ISO 10646-1 BMP/Unicode wide character is represented in UCS
+   --  Transformation Format 8 (UTF-8), as defined in Annex R of ISO
+   --  10646-1/Am.2. Depending on the character value, a Unicode character
    --  is represented as the one to six byte sequence.
    --
    --    16#0000_0000#-16#0000_007f#: 2#0xxxxxxx#
@@ -151,7 +154,8 @@ package System.WCh_Con is
    --  where the xxx bits correspond to the left-padded bits of the
    --  16-bit character value. Note that all lower half ASCII characters
    --  are represented as ASCII bytes and all upper half characters and
-   --  other wide characters are represented as sequences of upper-half.
+   --  other wide characters are represented as sequences of upper-half. This
+   --  encoding method can represent the entire range of Wide_Wide_Character.
 
    WCEM_Brackets : constant WC_Encoding_Method := 6;
    --  A wide character is represented using one of the following sequences:
@@ -161,7 +165,10 @@ package System.WCh_Con is
    --    ["xxxxxx"]
    --    ["xxxxxxxx"]
    --
-   --  where xx are hexadecimal digits representing the character code.
+   --  where xx are hexadecimal digits representing the character code. This
+   --  encoding method can represent the entire range of Wide_Wide_Character
+   --  but in the general case results in ambiguous representations (there is
+   --  no ambiguity in Ada sources, since the above sequences are illegal Ada).
 
    WC_Encoding_Letters : constant array (WC_Encoding_Method) of Character :=
      (WCEM_Hex       => 'h',
@@ -183,10 +190,20 @@ package System.WCh_Con is
    --  Encoding methods using an upper half character (16#80#..16#FF) at
    --  the start of the sequence.
 
-   WC_Longest_Sequence : constant := 10;
+   WC_Longest_Sequence : constant := 12;
    --  The longest number of characters that can be used for a wide character
    --  or wide wide character sequence for any of the active encoding methods.
 
+   WC_Longest_Sequences : constant array (WC_Encoding_Method) of Natural :=
+     (WCEM_Hex       => 5,
+      WCEM_Upper     => 2,
+      WCEM_Shift_JIS => 2,
+      WCEM_EUC       => 2,
+      WCEM_UTF8      => 6,
+      WCEM_Brackets  => 12);
+   --  The longest number of characters that can be used for a wide character
+   --  or wide wide character sequence using the given encoding method.
+
    function Get_WC_Encoding_Method (C : Character) return WC_Encoding_Method;
    --  Given a character C, returns corresponding encoding method (see array
    --  WC_Encoding_Letters above). Raises Constraint_Error if not in list.
@@ -196,4 +213,12 @@ package System.WCh_Con is
    --  utf8, brackets, return the corresponding encoding method. Raises
    --  Constraint_Error if not in list.
 
+   function Is_Start_Of_Encoding
+     (C  : Character;
+      EM : WC_Encoding_Method) return Boolean;
+   pragma Inline (Is_Start_Of_Encoding);
+   --  Returns True if the Character C is the start of a multi-character
+   --  encoding sequence for the given encoding method EM. If EM is set to
+   --  WCEM_Brackets, this function always returns False.
+
 end System.WCh_Con;
diff --git a/gcc/ada/switch-b.adb b/gcc/ada/switch-b.adb
index 0938c10..793d8da 100644
--- a/gcc/ada/switch-b.adb
+++ b/gcc/ada/switch-b.adb
@@ -417,21 +417,21 @@ package body Switch.B is
          --  Processing for W switch
 
          when 'W' =>
-            if Ptr = Max then
-               Bad_Switch (Switch_Chars);
-            end if;
-
             Ptr := Ptr + 1;
 
-            for J in WC_Encoding_Method loop
-               if Switch_Chars (Ptr) = WC_Encoding_Letters (J) then
-                  Wide_Character_Encoding_Method := J;
-                  exit;
+            if Ptr > Max then
+               Bad_Switch (Switch_Chars);
+            end if;
 
-               elsif J = WC_Encoding_Method'Last then
+            begin
+               Wide_Character_Encoding_Method :=
+                 Get_WC_Encoding_Method (Switch_Chars (Ptr));
+            exception
+               when Constraint_Error =>
                   Bad_Switch (Switch_Chars);
-               end if;
-            end loop;
+            end;
+
+            Wide_Character_Encoding_Method_Specified := True;
 
             Upper_Half_Encoding :=
               Wide_Character_Encoding_Method in
diff --git a/gcc/ada/switch-c.adb b/gcc/ada/switch-c.adb
index 76c47f2..bd63fae 100644
--- a/gcc/ada/switch-c.adb
+++ b/gcc/ada/switch-c.adb
@@ -479,6 +479,7 @@ package body Switch.C is
                Constant_Condition_Warnings     := True;
                Implementation_Unit_Warnings    := True;
                Ineffective_Inline_Warnings     := True;
+               Warn_On_Assertion_Failure       := True;
                Warn_On_Assumed_Low_Bound       := True;
                Warn_On_Bad_Fixed_Value         := True;
                Warn_On_Constant                := True;
@@ -833,9 +834,11 @@ package body Switch.C is
                      Bad_Switch ("-gnatW" & Switch_Chars (Ptr .. Max));
                end;
 
+               Wide_Character_Encoding_Method_Specified := True;
+
                Upper_Half_Encoding :=
                  Wide_Character_Encoding_Method in
-                 WC_Upper_Half_Encoding_Method;
+                   WC_Upper_Half_Encoding_Method;
 
                Ptr := Ptr + 1;