path: root/gcc/ada/ali.adb

------------------------------------------------------------------------------
--                                                                          --
--                         GNAT COMPILER COMPONENTS                         --
--                                                                          --
--                                  A L I                                   --
--                                                                          --
--                                 B o d y                                  --
--                                                                          --
--          Copyright (C) 1992-2004 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 Butil;  use Butil;
with Debug;  use Debug;
with Fname;  use Fname;
with Namet;  use Namet;
with Opt;    use Opt;
with Osint;  use Osint;
with Output; use Output;

package body ALI is

   use ASCII;
   --  Make control characters visible

   --  The following variable records which characters currently are
   --  used as line type markers in the ALI file. This is used in
   --  Scan_ALI to detect (or skip) invalid lines.

   Known_ALI_Lines : constant array (Character range 'A' .. 'Z') of Boolean :=
     ('V'    => True,   -- version
      'M'    => True,   -- main program
      'A'    => True,   -- argument
      'P'    => True,   -- program
      'R'    => True,   -- restriction
      'I'    => True,   -- interrupt
      'U'    => True,   -- unit
      'W'    => True,   -- with
      'L'    => True,   -- linker option
      'E'    => True,   -- external
      'D'    => True,   -- dependency
      'X'    => True,   -- xref
      others => False);

   --------------------
   -- Initialize_ALI --
   --------------------

   procedure Initialize_ALI is
   begin
      --  When (re)initializing ALI data structures the ALI user expects to
      --  get a fresh set of data structures. Thus we first need to erase the
      --  marks put in the name table by the previous set of ALI routine calls.
      --  These two loops are empty and harmless the first time in.

      for J in ALIs.First .. ALIs.Last loop
         Set_Name_Table_Info (ALIs.Table (J).Afile, 0);
      end loop;

      for J in Units.First .. Units.Last loop
         Set_Name_Table_Info (Units.Table (J).Uname, 0);
      end loop;

      --  Free argument table strings

      for J in Args.First .. Args.Last loop
         Free (Args.Table (J));
      end loop;

      --  Initialize all tables

      ALIs.Init;
      Units.Init;
      Withs.Init;
      Sdep.Init;
      Linker_Options.Init;
      Xref_Section.Init;
      Xref_Entity.Init;
      Xref.Init;
      Version_Ref.Reset;

      --  Add dummy zero'th item in Linker_Options for the sort function

      Linker_Options.Increment_Last;

      --  Initialize global variables recording cumulative options in all
      --  ALI files that are read for a given processing run in gnatbind.

      Dynamic_Elaboration_Checks_Specified := False;
      Float_Format_Specified               := ' ';
      Locking_Policy_Specified             := ' ';
      No_Normalize_Scalars_Specified       := False;
      No_Object_Specified                  := False;
      Normalize_Scalars_Specified          := False;
      Queuing_Policy_Specified             := ' ';
      Static_Elaboration_Model_Used        := False;
      Task_Dispatching_Policy_Specified    := ' ';
      Unreserve_All_Interrupts_Specified   := False;
      Zero_Cost_Exceptions_Specified       := False;
   end Initialize_ALI;

   --------------
   -- Scan_ALI --
   --------------

   function Scan_ALI
     (F             : File_Name_Type;
      T             : Text_Buffer_Ptr;
      Ignore_ED     : Boolean;
      Err           : Boolean;
      Read_Xref     : Boolean := False;
      Read_Lines    : String  := "";
      Ignore_Lines  : String  := "X";
      Ignore_Errors : Boolean := False) return ALI_Id
   is
      P         : Text_Ptr := T'First;
      Line      : Logical_Line_Number := 1;
      Id        : ALI_Id;
      C         : Character;
      NS_Found  : Boolean;
      First_Arg : Arg_Id;

      Ignore : array (Character range 'A' .. 'Z') of Boolean;
      --  Ignore (X) is set to True if lines starting with X are to
      --  be ignored by Scan_ALI and skipped, and False if the lines
      --  are to be read and processed.

      Restrictions_Initial : Rident.Restrictions_Info;
      pragma Warnings (Off, Restrictions_Initial);
      --  This variable, which should really be a constant (but that's not
      --  allowed by the language) is used only for initialization, and the
      --  reason we are declaring it is to get the default initialization
      --  set for the object.

      Bad_ALI_Format : exception;
      --  Exception raised by Fatal_Error if Err is True

      function At_Eol return Boolean;
      --  Test if at end of line

      function At_End_Of_Field return Boolean;
      --  Test if at end of line, or if at blank or horizontal tab

      procedure Check_At_End_Of_Field;
      --  Check if we are at end of field, fatal error if not

      procedure Checkc (C : Character);
      --  Check next character is C. If so bump past it, if not fatal error

      procedure Check_Unknown_Line;
      --  If Ignore_Errors mode, then checks C to make sure that it is not
      --  an unknown ALI line type characters, and if so, skips lines
      --  until the first character of the line is one of these characters,
      --  at which point it does a Getc to put that character in C. The
      --  call has no effect if C is already an appropriate character.
      --  If not in Ignore_Errors mode, a fatal error is signalled if the
      --  line is unknown. Note that if C is an EOL on entry, the line is
      --  skipped (it is assumed that blank lines are never significant).
      --  If C is EOF on entry, the call has no effect (it is assumed that
      --  the caller will properly handle this case).

      procedure Fatal_Error;
      --  Generate fatal error message for badly formatted ALI file if
      --  Err is false, or raise Bad_ALI_Format if Err is True.

      procedure Fatal_Error_Ignore;
      pragma Inline (Fatal_Error_Ignore);
      --  In Ignore_Errors mode, has no effect, otherwise same as Fatal_Error

      function Getc return Character;
      --  Get next character, bumping P past the character obtained

      function Get_Name
        (Lower         : Boolean := False;
         Ignore_Spaces : Boolean := False) return Name_Id;
      --  Skip blanks, then scan out a name (name is left in Name_Buffer with
      --  length in Name_Len, as well as being returned in Name_Id form).
      --  If Lower is set to True then the Name_Buffer will be converted to
      --  all lower case, for systems where file names are not case sensitive.
      --  This ensures that gnatbind works correctly regardless of the case
      --  of the file name on all systems. The name is terminated by a either
      --  white space (when Ignore_Spaces is False) or a typeref bracket or
      --  an equal sign except for the special case of an operator name
      --  starting with a double quite which is terminated by another double
      --  quote.

      function Get_Nat return Nat;
      --  Skip blanks, then scan out an unsigned integer value in Nat range.

      function Get_Stamp return Time_Stamp_Type;
      --  Skip blanks, then scan out a time stamp

      function Nextc return Character;
      --  Return current character without modifying pointer P

      procedure Skip_Eol;
      --  Skip past spaces, then skip past end of line (fatal error if not
      --  at end of line). Also skips past any following blank lines.

      procedure Skip_Line;
      --  Skip rest of current line and any following blank lines.

      procedure Skip_Space;
      --  Skip past white space (blanks or horizontal tab)

      procedure Skipc;
      --  Skip past next character, does not affect value in C. This call
      --  is like calling Getc and ignoring the returned result.

      ---------------------
      -- At_End_Of_Field --
      ---------------------

      function At_End_Of_Field return Boolean is
      begin
         return Nextc <= ' ';
      end At_End_Of_Field;

      ------------
      -- At_Eol --
      ------------

      function At_Eol return Boolean is
      begin
         return Nextc = EOF or else Nextc = CR or else Nextc = LF;
      end At_Eol;

      ---------------------------
      -- Check_At_End_Of_Field --
      ---------------------------

      procedure Check_At_End_Of_Field is
      begin
         if not At_End_Of_Field then
            if Ignore_Errors then
               while Nextc > ' ' loop
                  P := P + 1;
               end loop;
            else
               Fatal_Error;
            end if;
         end if;
      end Check_At_End_Of_Field;

      ------------
      -- Checkc --
      ------------

      procedure Checkc (C : Character) is
      begin
         if Nextc = C then
            P := P + 1;
         elsif Ignore_Errors then
            P := P + 1;
         else
            Fatal_Error;
         end if;
      end Checkc;

      ------------------------
      -- Check_Unknown_Line --
      ------------------------

      procedure Check_Unknown_Line is
      begin
         while C not in 'A' .. 'Z'
           or else not Known_ALI_Lines (C)
         loop
            if C = CR or else C = LF then
               Skip_Line;
               C := Nextc;

            elsif C = EOF then
               return;

            elsif Ignore_Errors then
               Skip_Line;
               C := Getc;

            else
               Fatal_Error;
            end if;
         end loop;
      end Check_Unknown_Line;

      -----------------
      -- Fatal_Error --
      -----------------

      procedure Fatal_Error is
         Ptr1 : Text_Ptr;
         Ptr2 : Text_Ptr;
         Col  : Int;

         procedure Wchar (C : Character);
         --  Write a single character, replacing horizontal tab by spaces

         procedure Wchar (C : Character) is
         begin
            if C = HT then
               loop
                  Wchar (' ');
                  exit when Col mod 8 = 0;
               end loop;

            else
               Write_Char (C);
               Col := Col + 1;
            end if;
         end Wchar;

      --  Start of processing for Fatal_Error

      begin
         if Err then
            raise Bad_ALI_Format;
         end if;

         Set_Standard_Error;
         Write_Str ("fatal error: file ");
         Write_Name (F);
         Write_Str (" is incorrectly formatted");
         Write_Eol;
         Write_Str
           ("make sure you are using consistent versions of gcc/gnatbind");
         Write_Eol;

         --  Find start of line

         Ptr1 := P;

         while Ptr1 > T'First
           and then T (Ptr1 - 1) /= CR
           and then T (Ptr1 - 1) /= LF
         loop
            Ptr1 := Ptr1 - 1;
         end loop;

         Write_Int (Int (Line));
         Write_Str (". ");

         if Line < 100 then
            Write_Char (' ');
         end if;

         if Line < 10 then
            Write_Char (' ');
         end if;

         Col := 0;
         Ptr2 := Ptr1;

         while Ptr2 < T'Last
           and then T (Ptr2) /= CR
           and then T (Ptr2) /= LF
         loop
            Wchar (T (Ptr2));
            Ptr2 := Ptr2 + 1;
         end loop;

         Write_Eol;

         Write_Str ("     ");
         Col := 0;

         while Ptr1 < P loop
            if T (Ptr1) = HT then
               Wchar (HT);
            else
               Wchar (' ');
            end if;

            Ptr1 := Ptr1 + 1;
         end loop;

         Wchar ('|');
         Write_Eol;

         Exit_Program (E_Fatal);
      end Fatal_Error;

      ------------------------
      -- Fatal_Error_Ignore --
      ------------------------

      procedure Fatal_Error_Ignore is
      begin
         if not Ignore_Errors then
            Fatal_Error;
         end if;
      end Fatal_Error_Ignore;

      --------------
      -- Get_Name --
      --------------

      function Get_Name
        (Lower         : Boolean := False;
         Ignore_Spaces : Boolean := False) return Name_Id
      is
      begin
         Name_Len := 0;
         Skip_Space;

         if At_Eol then
            if Ignore_Errors then
               return Error_Name;
            else
               Fatal_Error;
            end if;
         end if;

         loop
            Name_Len := Name_Len + 1;
            Name_Buffer (Name_Len) := Getc;

            exit when At_End_Of_Field and not Ignore_Spaces;

            if Name_Buffer (1) = '"' then
               exit when Name_Len > 1 and then Name_Buffer (Name_Len) = '"';

            else
               exit when (At_End_Of_Field and not Ignore_Spaces)
                 or else Nextc = '(' or else Nextc = ')'
                 or else Nextc = '{' or else Nextc = '}'
                 or else Nextc = '<' or else Nextc = '>'
                 or else Nextc = '=';
            end if;
         end loop;

         --  Convert file name to all lower case if file names are not case
         --  sensitive. This ensures that we handle names in the canonical
         --  lower case format, regardless of the actual case.

         if Lower and not File_Names_Case_Sensitive then
            Canonical_Case_File_Name (Name_Buffer (1 .. Name_Len));
         end if;

         return Name_Find;
      end Get_Name;

      -------------
      -- Get_Nat --
      -------------

      function Get_Nat return Nat is
         V : Nat;

      begin
         Skip_Space;

         V := 0;
         loop
            V := V * 10 + (Character'Pos (Getc) - Character'Pos ('0'));
            exit when At_End_Of_Field;
            exit when Nextc < '0' or Nextc > '9';
         end loop;

         return V;
      end Get_Nat;

      ---------------
      -- Get_Stamp --
      ---------------

      function Get_Stamp return Time_Stamp_Type is
         T     : Time_Stamp_Type;
         Start : Integer;

      begin
         Skip_Space;

         if At_Eol then
            if Ignore_Errors then
               return Dummy_Time_Stamp;
            else
               Fatal_Error;
            end if;
         end if;

         --  Following reads old style time stamp missing first two digits

         if Nextc in '7' .. '9' then
            T (1) := '1';
            T (2) := '9';
            Start := 3;

         --  Normal case of full year in time stamp

         else
            Start := 1;
         end if;

         for J in Start .. T'Last loop
            T (J) := Getc;
         end loop;

         return T;
      end Get_Stamp;

      ----------
      -- Getc --
      ----------

      function Getc return Character is
      begin
         if P = T'Last then
            return EOF;
         else
            P := P + 1;
            return T (P - 1);
         end if;
      end Getc;

      -----------
      -- Nextc --
      -----------

      function Nextc return Character is
      begin
         return T (P);
      end Nextc;

      --------------
      -- Skip_Eol --
      --------------

      procedure Skip_Eol is
      begin
         Skip_Space;

         if not At_Eol then
            if Ignore_Errors then
               while not At_Eol loop
                  P := P + 1;
               end loop;
            else
               Fatal_Error;
            end if;
         end if;

         --  Loop to skip past blank lines (first time through skips this EOL)

         while Nextc < ' ' and then Nextc /= EOF loop
            if Nextc = LF then
               Line := Line + 1;
            end if;

            P := P + 1;
         end loop;
      end Skip_Eol;

      ---------------
      -- Skip_Line --
      ---------------

      procedure Skip_Line is
      begin
         while not At_Eol loop
            P := P + 1;
         end loop;

         Skip_Eol;
      end Skip_Line;

      ----------------
      -- Skip_Space --
      ----------------

      procedure Skip_Space is
      begin
         while Nextc = ' ' or else Nextc = HT loop
            P := P + 1;
         end loop;
      end Skip_Space;

      -----------
      -- Skipc --
      -----------

      procedure Skipc is
      begin
         if P /= T'Last then
            P := P + 1;
         end if;
      end Skipc;

   --  Start of processing for Scan_ALI

   begin
      First_Sdep_Entry := Sdep.Last + 1;

      --  Acquire lines to be ignored

      if Read_Xref then
         Ignore := ('U' | 'W' | 'D' | 'X' => False, others => True);

      --  Read_Lines parameter given

      elsif Read_Lines /= "" then
         Ignore := ('U' => False, others => True);

         for J in Read_Lines'Range loop
            Ignore (Read_Lines (J)) := False;
         end loop;

      --  Process Ignore_Lines parameter

      else
         Ignore := (others => False);

         for J in Ignore_Lines'Range loop
            pragma Assert (Ignore_Lines (J) /= 'U');
            Ignore (Ignore_Lines (J)) := True;
         end loop;
      end if;

      --  Setup ALI Table entry with appropriate defaults

      ALIs.Increment_Last;
      Id := ALIs.Last;
      Set_Name_Table_Info (F, Int (Id));

      ALIs.Table (Id) := (
        Afile                      => F,
        Compile_Errors             => False,
        First_Interrupt_State      => Interrupt_States.Last + 1,
        First_Sdep                 => No_Sdep_Id,
        First_Unit                 => No_Unit_Id,
        Float_Format               => 'I',
        Last_Interrupt_State       => Interrupt_States.Last,
        Last_Sdep                  => No_Sdep_Id,
        Last_Unit                  => No_Unit_Id,
        Locking_Policy             => ' ',
        Main_Priority              => -1,
        Main_Program               => None,
        No_Object                  => False,
        Normalize_Scalars          => False,
        Ofile_Full_Name            => Full_Object_File_Name,
        Queuing_Policy             => ' ',
        Restrictions               => Restrictions_Initial,
        Sfile                      => No_Name,
        Task_Dispatching_Policy    => ' ',
        Time_Slice_Value           => -1,
        WC_Encoding                => '8',
        Unit_Exception_Table       => False,
        Ver                        => (others => ' '),
        Ver_Len                    => 0,
        Interface                  => False,
        Zero_Cost_Exceptions       => False);

      --  Now we acquire the input lines from the ALI file. Note that the
      --  convention in the following code is that as we enter each section,
      --  C is set to contain the first character of the following line.

      C := Getc;
      Check_Unknown_Line;

      --  Acquire library version

      if C /= 'V' then

         --  The V line missing really indicates trouble, most likely it
         --  means we don't have an ALI file at all, so here we give a
         --  fatal error even if we are in Ignore_Errors mode.

         Fatal_Error;

      elsif Ignore ('V') then
         Skip_Line;

      else
         Checkc (' ');
         Skip_Space;
         Checkc ('"');

         for J in 1 .. Ver_Len_Max loop
            C := Getc;
            exit when C = '"';
            ALIs.Table (Id).Ver (J) := C;
            ALIs.Table (Id).Ver_Len := J;
         end loop;

         Skip_Eol;
      end if;

      C := Getc;
      Check_Unknown_Line;

      --  Acquire main program line if present

      if C = 'M' then
         if Ignore ('M') then
            Skip_Line;

         else
            Checkc (' ');
            Skip_Space;

            C := Getc;

            if C = 'F' then
               ALIs.Table (Id).Main_Program := Func;
            elsif C = 'P' then
               ALIs.Table (Id).Main_Program := Proc;
            else
               P := P - 1;
               Fatal_Error;
            end if;

            Skip_Space;

            if not At_Eol then
               if Nextc < 'A' then
                  ALIs.Table (Id).Main_Priority := Get_Nat;
               end if;

               Skip_Space;

               if Nextc = 'T' then
                  P := P + 1;
                  Checkc ('=');
                  ALIs.Table (Id).Time_Slice_Value := Get_Nat;
               end if;

               Skip_Space;

               Checkc ('W');
               Checkc ('=');
               ALIs.Table (Id).WC_Encoding := Getc;
            end if;

            Skip_Eol;
         end if;

         C := Getc;
      end if;

      --  Acquire argument lines

      First_Arg := Args.Last + 1;

      A_Loop : loop
         Check_Unknown_Line;
         exit A_Loop when C /= 'A';

         if Ignore ('A') then
            Skip_Line;

         else
            Checkc (' ');
            Name_Len := 0;

            while not At_Eol loop
               Name_Len := Name_Len + 1;
               Name_Buffer (Name_Len) := Getc;
            end loop;

            Args.Increment_Last;
            Args.Table (Args.Last) := new String'(Name_Buffer (1 .. Name_Len));

            Skip_Eol;
         end if;

         C := Getc;
      end loop A_Loop;

      --  Acquire P line

      Check_Unknown_Line;

      while C /= 'P' loop
         if Ignore_Errors then
            if C = EOF then
               Fatal_Error;
            else
               Skip_Line;
               C := Nextc;
            end if;
         else
            Fatal_Error;
         end if;
      end loop;

      if Ignore ('P') then
         Skip_Line;

      --  Process P line

      else
         NS_Found := False;

         while not At_Eol loop
            Checkc (' ');
            Skip_Space;
            C := Getc;

            --  Processing for CE

            if C = 'C' then
               Checkc ('E');
               ALIs.Table (Id).Compile_Errors := True;

            --  Processing for DB

            elsif C = 'D' then
               Checkc ('B');
               Detect_Blocking := True;

            --  Processing for FD/FG/FI

            elsif C = 'F' then
               Float_Format_Specified := Getc;
               ALIs.Table (Id).Float_Format := Float_Format_Specified;

            --  Processing for Lx

            elsif C = 'L' then
               Locking_Policy_Specified := Getc;
               ALIs.Table (Id).Locking_Policy := Locking_Policy_Specified;

            --  Processing for flags starting with N

            elsif C = 'N' then
               C := Getc;

               --  Processing for NO

               if C = 'O' then
                  ALIs.Table (Id).No_Object := True;
                  No_Object_Specified := True;

               --  Processing for NR

               elsif C = 'R' then
                  No_Run_Time_Mode           := True;
                  Configurable_Run_Time_Mode := True;

               --  Processing for NS

               elsif C = 'S' then
                  ALIs.Table (Id).Normalize_Scalars := True;
                  Normalize_Scalars_Specified := True;
                  NS_Found := True;

               --  Invalid switch starting with N

               else
                  Fatal_Error_Ignore;
               end if;

            --  Processing for Qx

            elsif C = 'Q' then
               Queuing_Policy_Specified := Getc;
               ALIs.Table (Id).Queuing_Policy := Queuing_Policy_Specified;

            --  Processing for flags starting with S

            elsif C = 'S' then
               C := Getc;

               --  Processing for SL

               if C = 'L' then
                  ALIs.Table (Id).Interface := True;

               --  Processing for SS

               elsif C = 'S' then
                  Opt.Sec_Stack_Used := True;

               --  Invalid switch starting with S

               else
                  Fatal_Error_Ignore;
               end if;

            --  Processing for Tx

            elsif C = 'T' then
               Task_Dispatching_Policy_Specified := Getc;
               ALIs.Table (Id).Task_Dispatching_Policy :=
                 Task_Dispatching_Policy_Specified;

            --  Processing for switch starting with U

            elsif C = 'U' then
               C := Getc;

               --  Processing for UA

               if C  = 'A' then
                  Unreserve_All_Interrupts_Specified := True;

               --  Processing for UX

               elsif C = 'X' then
                  ALIs.Table (Id).Unit_Exception_Table := True;

               --  Invalid switches starting with U

               else
                  Fatal_Error_Ignore;
               end if;

            --  Processing for ZX

            elsif C = 'Z' then
               C := Getc;

               if C = 'X' then
                  ALIs.Table (Id).Zero_Cost_Exceptions := True;
                  Zero_Cost_Exceptions_Specified := True;
               else
                  Fatal_Error_Ignore;
               end if;

            --  Invalid parameter

            else
               C := Getc;
               Fatal_Error_Ignore;
            end if;
         end loop;

         if not NS_Found then
            No_Normalize_Scalars_Specified := True;
         end if;

         Skip_Eol;
      end if;

      C := Getc;
      Check_Unknown_Line;

      --  Acquire restrictions line

      while C /= 'R' loop
         if Ignore_Errors then
            if C = EOF then
               Fatal_Error;
            else
               Skip_Line;
               C := Nextc;
            end if;
         else
            Fatal_Error;
         end if;
      end loop;

      if Ignore ('R') then
         Skip_Line;

      --  Process restrictions line

      else
         Scan_Restrictions : declare
            Save_R : constant Restrictions_Info := Cumulative_Restrictions;
            --  Save cumulative restrictions in case we have a fatal error

            Bad_R_Line : exception;
            --  Signal bad restrictions line

         begin
            Checkc (' ');
            Skip_Space;

            --  Acquire information for boolean restrictions

            for R in All_Boolean_Restrictions loop
               C := Getc;

               case C is
                  when 'v' =>
                     ALIs.Table (Id).Restrictions.Violated (R) := True;
                     Cumulative_Restrictions.Violated (R) := True;

                  when 'r' =>
                     ALIs.Table (Id).Restrictions.Set (R) := True;
                     Cumulative_Restrictions.Set (R) := True;

                  when 'n' =>
                     null;

                  when others =>
                     Fatal_Error;
               end case;
            end loop;

            --  Acquire information for parameter restrictions

            for RP in All_Parameter_Restrictions loop

               --  Acquire restrictions pragma information

               case Getc is
                  when 'n' =>
                     null;

                  when 'r' =>
                     ALIs.Table (Id).Restrictions.Set (RP) := True;

                     declare
                        N : constant Integer := Integer (Get_Nat);
                     begin
                        ALIs.Table (Id).Restrictions.Value (RP) := N;

                        if Cumulative_Restrictions.Set (RP) then
                           Cumulative_Restrictions.Value (RP) :=
                             Integer'Min
                               (Cumulative_Restrictions.Value (RP), N);
                        else
                           Cumulative_Restrictions.Set (RP) := True;
                           Cumulative_Restrictions.Value (RP) := N;
                        end if;
                     end;

                  when others =>
                     Fatal_Error;
               end case;

               --  Acquire restrictions violations information

               case Getc is
                  when 'n' =>
                     null;

                  when 'v' =>
                     ALIs.Table (Id).Restrictions.Violated (RP) := True;
                     Cumulative_Restrictions.Violated (RP) := True;

                     declare
                        N : constant Integer := Integer (Get_Nat);
                        pragma Unsuppress (Overflow_Check);

                     begin
                        ALIs.Table (Id).Restrictions.Count (RP) := N;

                        if RP in Checked_Max_Parameter_Restrictions then
                           Cumulative_Restrictions.Count (RP) :=
                             Integer'Max
                               (Cumulative_Restrictions.Count (RP), N);
                        else
                           Cumulative_Restrictions.Count (RP) :=
                             Cumulative_Restrictions.Count (RP) + N;
                        end if;

                     exception
                        when Constraint_Error =>

                           --  A constraint error comes from the addition in
                           --  the else branch. We reset to the maximum and
                           --  indicate that the real value is now unknown.

                           Cumulative_Restrictions.Value (RP) := Integer'Last;
                           Cumulative_Restrictions.Unknown (RP) := True;
                     end;

                     if Nextc = '+' then
                        Skipc;
                        ALIs.Table (Id).Restrictions.Unknown (RP) := True;
                        Cumulative_Restrictions.Unknown (RP) := True;
                     end if;

                  when others =>
                     Fatal_Error;
               end case;
            end loop;

            Skip_Eol;

         --  Here if error during scanning of restrictions line

         exception
            when Bad_R_Line =>

               --  In Ignore_Errors mode, undo any changes to restrictions
               --  from this unit, and continue on.

               if Ignore_Errors then
                  Cumulative_Restrictions := Save_R;
                  ALIs.Table (Id).Restrictions := Restrictions_Initial;

               --  In normal mode, this is a fatal error

               else
                  Fatal_Error;
               end if;

         end Scan_Restrictions;
      end if;

      --  Acquire 'I' lines if present

      C := Getc;
      Check_Unknown_Line;

      while C = 'I' loop
         if Ignore ('I') then
            Skip_Line;

         else
            declare
               Int_Num : Nat;
               I_State : Character;
               Line_No : Nat;

            begin
               Int_Num := Get_Nat;
               Skip_Space;
               I_State := Getc;
               Line_No := Get_Nat;

               Interrupt_States.Append (
                 (Interrupt_Id    => Int_Num,
                  Interrupt_State => I_State,
                  IS_Pragma_Line  => Line_No));

               ALIs.Table (Id).Last_Interrupt_State := Interrupt_States.Last;
               Skip_Eol;
            end;
         end if;

         C := Getc;
      end loop;

      --  Loop to acquire unit entries

      U_Loop : loop
         Check_Unknown_Line;
         exit U_Loop when C /= 'U';

         --  Note: as per spec, we never ignore U lines

         Checkc (' ');
         Skip_Space;
         Units.Increment_Last;

         if ALIs.Table (Id).First_Unit = No_Unit_Id then
            ALIs.Table (Id).First_Unit := Units.Last;
         end if;

         Units.Table (Units.Last).Uname           := Get_Name;
         Units.Table (Units.Last).Predefined      := Is_Predefined_Unit;
         Units.Table (Units.Last).Internal        := Is_Internal_Unit;
         Units.Table (Units.Last).My_ALI          := Id;
         Units.Table (Units.Last).Sfile           := Get_Name (Lower => True);
         Units.Table (Units.Last).Pure            := False;
         Units.Table (Units.Last).Preelab         := False;
         Units.Table (Units.Last).No_Elab         := False;
         Units.Table (Units.Last).Shared_Passive  := False;
         Units.Table (Units.Last).RCI             := False;
         Units.Table (Units.Last).Remote_Types    := False;
         Units.Table (Units.Last).Has_RACW        := False;
         Units.Table (Units.Last).Init_Scalars    := False;
         Units.Table (Units.Last).Is_Generic      := False;
         Units.Table (Units.Last).Icasing         := Mixed_Case;
         Units.Table (Units.Last).Kcasing         := All_Lower_Case;
         Units.Table (Units.Last).Dynamic_Elab    := False;
         Units.Table (Units.Last).Elaborate_Body  := False;
         Units.Table (Units.Last).Set_Elab_Entity := False;
         Units.Table (Units.Last).Version         := "00000000";
         Units.Table (Units.Last).First_With      := Withs.Last + 1;
         Units.Table (Units.Last).First_Arg       := First_Arg;
         Units.Table (Units.Last).Elab_Position   := 0;
         Units.Table (Units.Last).Interface       := ALIs.Table (Id).Interface;
         Units.Table (Units.Last).Body_Needed_For_SAL := False;

         if Debug_Flag_U then
            Write_Str (" ----> reading unit ");
            Write_Int (Int (Units.Last));
            Write_Str ("  ");
            Write_Unit_Name (Units.Table (Units.Last).Uname);
            Write_Str (" from file ");
            Write_Name (Units.Table (Units.Last).Sfile);
            Write_Eol;
         end if;

         --  Check for duplicated unit in different files

         declare
            Info : constant Int := Get_Name_Table_Info
                                     (Units.Table (Units.Last).Uname);
         begin
            if Info /= 0
              and then Units.Table (Units.Last).Sfile /=
                       Units.Table (Unit_Id (Info)).Sfile
            then
               --  If Err is set then ignore duplicate unit name. This is the
               --  case of a call from gnatmake, where the situation can arise
               --  from substitution of source files. In such situations, the
               --  processing in gnatmake will always result in any required
               --  recompilations in any case, and if we consider this to be
               --  an error we get strange cases (for example when a generic
               --  instantiation is replaced by a normal package) where we
               --  read the old ali file, decide to recompile, and then decide
               --  that the old and new ali files are incompatible.

               if Err then
                  null;

               --  If Err is not set, then this is a fatal error. This is
               --  the case of being called from the binder, where we must
               --  definitely diagnose this as an error.

               else
                  Set_Standard_Error;
                  Write_Str ("error: duplicate unit name: ");
                  Write_Eol;

                  Write_Str ("error: unit """);
                  Write_Unit_Name (Units.Table (Units.Last).Uname);
                  Write_Str (""" found in file """);
                  Write_Name_Decoded (Units.Table (Units.Last).Sfile);
                  Write_Char ('"');
                  Write_Eol;

                  Write_Str ("error: unit """);
                  Write_Unit_Name (Units.Table (Unit_Id (Info)).Uname);
                  Write_Str (""" found in file """);
                  Write_Name_Decoded (Units.Table (Unit_Id (Info)).Sfile);
                  Write_Char ('"');
                  Write_Eol;

                  Exit_Program (E_Fatal);
               end if;
            end if;
         end;

         Set_Name_Table_Info
           (Units.Table (Units.Last).Uname, Int (Units.Last));

         --  Scan out possible version and other parameters

         loop
            Skip_Space;
            exit when At_Eol;
            C := Getc;

            --  Version field

            if C in '0' .. '9' or else C in 'a' .. 'f' then
               Units.Table (Units.Last).Version (1) := C;

               for J in 2 .. 8 loop
                  C := Getc;
                  Units.Table (Units.Last).Version (J) := C;
               end loop;

            --  BN parameter (Body needed)

            elsif C = 'B' then
               C := Getc;

               if C = 'N' then
                  Check_At_End_Of_Field;
                  Units.Table (Units.Last).Body_Needed_For_SAL := True;
               else
                  Fatal_Error_Ignore;
               end if;


            --  DE parameter (Dynamic elaboration checks)

            elsif C = 'D' then
               C := Getc;

               if C = 'E' then
                  Check_At_End_Of_Field;
                  Units.Table (Units.Last).Dynamic_Elab := True;
                  Dynamic_Elaboration_Checks_Specified := True;
               else
                  Fatal_Error_Ignore;
               end if;

            --  EB/EE parameters

            elsif C = 'E' then
               C := Getc;

               if C = 'B' then
                  Units.Table (Units.Last).Elaborate_Body := True;
               elsif C = 'E' then
                  Units.Table (Units.Last).Set_Elab_Entity := True;
               else
                  Fatal_Error_Ignore;
               end if;

               Check_At_End_Of_Field;

            --  GE parameter (generic)

            elsif C = 'G' then
               C := Getc;

               if C = 'E' then
                  Check_At_End_Of_Field;
                  Units.Table (Units.Last).Is_Generic := True;
               else
                  Fatal_Error_Ignore;
               end if;

            --  IL/IS/IU parameters

            elsif C = 'I' then
               C := Getc;

               if C = 'L' then
                  Units.Table (Units.Last).Icasing := All_Lower_Case;
               elsif C = 'S' then
                  Units.Table (Units.Last).Init_Scalars := True;
                  Initialize_Scalars_Used := True;
               elsif C = 'U' then
                  Units.Table (Units.Last).Icasing := All_Upper_Case;
               else
                  Fatal_Error_Ignore;
               end if;

               Check_At_End_Of_Field;

            --  KM/KU parameters

            elsif C = 'K' then
               C := Getc;

               if C = 'M' then
                  Units.Table (Units.Last).Kcasing := Mixed_Case;
               elsif C = 'U' then
                  Units.Table (Units.Last).Kcasing := All_Upper_Case;
               else
                  Fatal_Error_Ignore;
               end if;

               Check_At_End_Of_Field;

            --  NE parameter

            elsif C = 'N' then
               C := Getc;

               if C = 'E' then
                  Units.Table (Units.Last).No_Elab := True;
                  Check_At_End_Of_Field;
               else
                  Fatal_Error_Ignore;
               end if;


            --  PR/PU/PK parameters

            elsif C = 'P' then
               C := Getc;

               if C = 'R' then
                  Units.Table (Units.Last).Preelab := True;
               elsif C = 'U' then
                  Units.Table (Units.Last).Pure := True;
               elsif C = 'K' then
                  Units.Table (Units.Last).Unit_Kind := 'p';
               else
                  Fatal_Error_Ignore;
               end if;

               Check_At_End_Of_Field;

            --  RC/RT parameters

            elsif C = 'R' then
               C := Getc;

               if C = 'C' then
                  Units.Table (Units.Last).RCI := True;
               elsif C = 'T' then
                  Units.Table (Units.Last).Remote_Types := True;
               elsif C = 'A' then
                  Units.Table (Units.Last).Has_RACW := True;
               else
                  Fatal_Error_Ignore;
               end if;

               Check_At_End_Of_Field;

            elsif C = 'S' then
               C := Getc;

               if C = 'P' then
                  Units.Table (Units.Last).Shared_Passive := True;
               elsif C = 'U' then
                  Units.Table (Units.Last).Unit_Kind := 's';
               else
                  Fatal_Error_Ignore;
               end if;

               Check_At_End_Of_Field;

            else
               C := Getc;
               Fatal_Error_Ignore;
            end if;
         end loop;

         Skip_Eol;

         --  Check if static elaboration model used

         if not Units.Table (Units.Last).Dynamic_Elab
           and then not Units.Table (Units.Last).Internal
         then
            Static_Elaboration_Model_Used := True;
         end if;

         C := Getc;

         --  Scan out With lines for this unit

         With_Loop : loop
            Check_Unknown_Line;
            exit With_Loop when C /= 'W';

            if Ignore ('W') then
               Skip_Line;

            else
               Checkc (' ');
               Skip_Space;
               Withs.Increment_Last;
               Withs.Table (Withs.Last).Uname              := Get_Name;
               Withs.Table (Withs.Last).Elaborate          := False;
               Withs.Table (Withs.Last).Elaborate_All      := False;
               Withs.Table (Withs.Last).Elab_All_Desirable := False;
               Withs.Table (Withs.Last).Interface          := False;

               --  Generic case with no object file available

               if At_Eol then
                  Withs.Table (Withs.Last).Sfile := No_File;
                  Withs.Table (Withs.Last).Afile := No_File;

               --  Normal case

               else
                  Withs.Table (Withs.Last).Sfile := Get_Name (Lower => True);
                  Withs.Table (Withs.Last).Afile := Get_Name;

                  --  Scan out possible E, EA, and NE parameters

                  while not At_Eol loop
                     Skip_Space;

                     if Nextc = 'E' then
                        P := P + 1;

                        if At_End_Of_Field then
                           Withs.Table (Withs.Last).Elaborate := True;

                        elsif Nextc = 'A' then
                           P := P + 1;
                           Check_At_End_Of_Field;
                           Withs.Table (Withs.Last).Elaborate_All := True;

                        else
                           Checkc ('D');
                           Check_At_End_Of_Field;

                           --  Store ED indication unless ignore required

                           if not Ignore_ED then
                              Withs.Table (Withs.Last).Elab_All_Desirable :=
                                True;
                           end if;
                        end if;
                     end if;
                  end loop;
               end if;

               Skip_Eol;
            end if;

            C := Getc;
         end loop With_Loop;

         Units.Table (Units.Last).Last_With := Withs.Last;
         Units.Table (Units.Last).Last_Arg  := Args.Last;

         --  If there are linker options lines present, scan them

         Name_Len := 0;

         Linker_Options_Loop : loop
            Check_Unknown_Line;
            exit Linker_Options_Loop when C /= 'L';

            if Ignore ('L') then
               Skip_Line;

            else
               Checkc (' ');
               Skip_Space;
               Checkc ('"');

               loop
                  C := Getc;

                  if C < Character'Val (16#20#)
                    or else C > Character'Val (16#7E#)
                  then
                     Fatal_Error_Ignore;

                  elsif C = '{' then
                     C := Character'Val (0);

                     declare
                        V : Natural;

                     begin
                        V := 0;
                        for J in 1 .. 2 loop
                           C := Getc;

                           if C in '0' .. '9' then
                              V := V * 16 +
                                     Character'Pos (C) -
                                       Character'Pos ('0');

                           elsif C in 'A' .. 'F' then
                              V := V * 16 +
                                     Character'Pos (C) -
                                       Character'Pos ('A') +
                                         10;

                           else
                              Fatal_Error_Ignore;
                           end if;
                        end loop;

                        Checkc ('}');
                        Add_Char_To_Name_Buffer (Character'Val (V));
                     end;

                  else
                     if C = '"' then
                        exit when Nextc /= '"';
                        C := Getc;
                     end if;

                     Add_Char_To_Name_Buffer (C);
                  end if;
               end loop;

               Add_Char_To_Name_Buffer (nul);
               Skip_Eol;
            end if;

            C := Getc;
         end loop Linker_Options_Loop;

         --  Store the linker options entry if one was found

         if Name_Len /= 0 then
            Linker_Options.Increment_Last;

            Linker_Options.Table (Linker_Options.Last).Name :=
              Name_Enter;

            Linker_Options.Table (Linker_Options.Last).Unit :=
              Units.Last;

            Linker_Options.Table (Linker_Options.Last).Internal_File :=
              Is_Internal_File_Name (F);

            Linker_Options.Table (Linker_Options.Last).Original_Pos :=
              Linker_Options.Last;
         end if;
      end loop U_Loop;

      --  End loop through units for one ALI file

      ALIs.Table (Id).Last_Unit := Units.Last;
      ALIs.Table (Id).Sfile := Units.Table (ALIs.Table (Id).First_Unit).Sfile;

      --  Set types of the units (there can be at most 2 of them)

      if ALIs.Table (Id).First_Unit /= ALIs.Table (Id).Last_Unit then
         Units.Table (ALIs.Table (Id).First_Unit).Utype := Is_Body;
         Units.Table (ALIs.Table (Id).Last_Unit).Utype  := Is_Spec;

      else
         --  Deal with body only and spec only cases, note that the reason we
         --  do our own checking of the name (rather than using Is_Body_Name)
         --  is that Uname drags in far too much compiler junk!

         Get_Name_String (Units.Table (Units.Last).Uname);

         if Name_Buffer (Name_Len) = 'b' then
            Units.Table (Units.Last).Utype := Is_Body_Only;
         else
            Units.Table (Units.Last).Utype := Is_Spec_Only;
         end if;
      end if;

      --  Scan out external version references and put in hash table

      E_Loop : loop
         Check_Unknown_Line;
         exit E_Loop when C /= 'E';

         if Ignore ('E') then
            Skip_Line;

         else
            Checkc (' ');
            Skip_Space;

            Name_Len := 0;
            Name_Len := 0;
            loop
               C := Getc;

               if C < ' ' then
                  Fatal_Error;
               end if;

               exit when At_End_Of_Field;
               Add_Char_To_Name_Buffer (C);
            end loop;

            Version_Ref.Set (new String'(Name_Buffer (1 .. Name_Len)), True);
            Skip_Eol;
         end if;

         C := Getc;
      end loop E_Loop;

      --  Scan out source dependency lines for this ALI file

      ALIs.Table (Id).First_Sdep := Sdep.Last + 1;

      D_Loop : loop
         Check_Unknown_Line;
         exit D_Loop when C /= 'D';

         if Ignore ('D') then
            Skip_Line;

         else
            Checkc (' ');
            Skip_Space;
            Sdep.Increment_Last;
            Sdep.Table (Sdep.Last).Sfile := Get_Name (Lower => True);
            Sdep.Table (Sdep.Last).Stamp := Get_Stamp;
            Sdep.Table (Sdep.Last).Dummy_Entry :=
              (Sdep.Table (Sdep.Last).Stamp = Dummy_Time_Stamp);

            --  Acquire checksum value

            Skip_Space;

            declare
               Ctr : Natural;
               Chk : Word;

            begin
               Ctr := 0;
               Chk := 0;

               loop
                  exit when At_Eol or else Ctr = 8;

                  if Nextc in '0' .. '9' then
                     Chk := Chk * 16 +
                              Character'Pos (Nextc) - Character'Pos ('0');

                  elsif Nextc in 'a' .. 'f' then
                     Chk := Chk * 16 +
                              Character'Pos (Nextc) - Character'Pos ('a') + 10;

                  else
                     exit;
                  end if;

                  Ctr := Ctr + 1;
                  P := P + 1;
               end loop;

               if Ctr = 8 and then At_End_Of_Field then
                  Sdep.Table (Sdep.Last).Checksum := Chk;
               else
                  Fatal_Error;
               end if;
            end;

            --  Acquire subunit and reference file name entries

            Sdep.Table (Sdep.Last).Subunit_Name := No_Name;
            Sdep.Table (Sdep.Last).Rfile        :=
              Sdep.Table (Sdep.Last).Sfile;
            Sdep.Table (Sdep.Last).Start_Line   := 1;

            if not At_Eol then
               Skip_Space;

               --  Here for subunit name

               if Nextc not in '0' .. '9' then
                  Name_Len := 0;

                  while not At_End_Of_Field loop
                     Name_Len := Name_Len + 1;
                     Name_Buffer (Name_Len) := Getc;
                  end loop;

                  Sdep.Table (Sdep.Last).Subunit_Name := Name_Enter;
                  Skip_Space;
               end if;

               --  Here for reference file name entry

               if Nextc in '0' .. '9' then
                  Sdep.Table (Sdep.Last).Start_Line := Get_Nat;
                  Checkc (':');

                  Name_Len := 0;

                  while not At_End_Of_Field loop
                     Name_Len := Name_Len + 1;
                     Name_Buffer (Name_Len) := Getc;
                  end loop;

                  Sdep.Table (Sdep.Last).Rfile := Name_Enter;
               end if;
            end if;

            Skip_Eol;
         end if;

         C := Getc;
      end loop D_Loop;

      ALIs.Table (Id).Last_Sdep := Sdep.Last;

      --  We must at this stage be at an Xref line or the end of file

      if C = EOF then
         return Id;
      end if;

      Check_Unknown_Line;

      if C /= 'X' then
         Fatal_Error;
      end if;

      --  If we are ignoring Xref sections we are done (we ignore all
      --  remaining lines since only xref related lines follow X).

      if Ignore ('X') and then not Debug_Flag_X then
         return Id;
      end if;

      --  Loop through Xref sections

      X_Loop : loop
         Check_Unknown_Line;
         exit X_Loop when C /= 'X';

         --  Make new entry in section table

         Xref_Section.Increment_Last;

         Read_Refs_For_One_File : declare
            XS : Xref_Section_Record renames
                   Xref_Section.Table (Xref_Section.Last);

            Current_File_Num : Sdep_Id;
            --  Keeps track of the current file number (changed by nn|)

         begin
            XS.File_Num     := Sdep_Id (Get_Nat + Nat (First_Sdep_Entry) - 1);
            XS.File_Name    := Get_Name;
            XS.First_Entity := Xref_Entity.Last + 1;

            Current_File_Num := XS.File_Num;

            Skip_Space;

            Skip_Eol;
            C := Nextc;

            --  Loop through Xref entities

            while C /= 'X' and then C /= EOF loop
               Xref_Entity.Increment_Last;

               Read_Refs_For_One_Entity : declare
                  XE : Xref_Entity_Record renames
                         Xref_Entity.Table (Xref_Entity.Last);
                  N  : Nat;

                  procedure Read_Instantiation_Reference;
                  --  Acquire instantiation reference. Caller has checked
                  --  that current character is '[' and on return the cursor
                  --  is skipped past the corresponding closing ']'.

                  ----------------------------------
                  -- Read_Instantiation_Reference --
                  ----------------------------------

                  procedure Read_Instantiation_Reference is
                     Local_File_Num : Sdep_Id := Current_File_Num;

                  begin
                     Xref.Increment_Last;

                     declare
                        XR : Xref_Record renames Xref.Table (Xref.Last);

                     begin
                        P := P + 1; -- skip [
                        N := Get_Nat;

                        if Nextc = '|' then
                           XR.File_Num :=
                             Sdep_Id (N + Nat (First_Sdep_Entry) - 1);
                           Local_File_Num := XR.File_Num;
                           P := P + 1;
                           N := Get_Nat;

                        else
                           XR.File_Num := Local_File_Num;
                        end if;

                        XR.Line  := N;
                        XR.Rtype := ' ';
                        XR.Col   := 0;

                        --  Recursive call for next reference

                        if Nextc = '[' then
                           pragma Warnings (Off); -- kill recursion warning
                           Read_Instantiation_Reference;
                           pragma Warnings (On);
                        end if;

                        --  Skip closing bracket after recursive call

                        P := P + 1;
                     end;
                  end Read_Instantiation_Reference;

               --  Start of processing for Read_Refs_For_One_Entity

               begin
                  XE.Line   := Get_Nat;
                  XE.Etype  := Getc;
                  XE.Col    := Get_Nat;
                  XE.Lib    := (Getc = '*');
                  XE.Entity := Get_Name;

                  Current_File_Num := XS.File_Num;

                  --  Renaming reference is present

                  if Nextc = '=' then
                     P := P + 1;
                     XE.Rref_Line := Get_Nat;

                     if Getc /= ':' then
                        Fatal_Error;
                     end if;

                     XE.Rref_Col := Get_Nat;

                  --  No renaming reference present

                  else
                     XE.Rref_Line := 0;
                     XE.Rref_Col  := 0;
                  end if;

                  Skip_Space;

                  --  See if type reference present

                  case Nextc is
                     when '<'    => XE.Tref := Tref_Derived;
                     when '('    => XE.Tref := Tref_Access;
                     when '{'    => XE.Tref := Tref_Type;
                     when others => XE.Tref := Tref_None;
                  end case;

                  --  Case of typeref field present

                  if XE.Tref /= Tref_None then
                     P := P + 1; -- skip opening bracket

                     if Nextc in 'a' .. 'z' then
                        XE.Tref_File_Num        := No_Sdep_Id;
                        XE.Tref_Line            := 0;
                        XE.Tref_Type            := ' ';
                        XE.Tref_Col             := 0;
                        XE.Tref_Standard_Entity :=
                          Get_Name (Ignore_Spaces => True);

                     else
                        N := Get_Nat;

                        if Nextc = '|' then
                           XE.Tref_File_Num :=
                             Sdep_Id (N + Nat (First_Sdep_Entry) - 1);
                           P := P + 1;
                           N := Get_Nat;

                        else
                           XE.Tref_File_Num := Current_File_Num;
                        end if;

                        XE.Tref_Line            := N;
                        XE.Tref_Type            := Getc;
                        XE.Tref_Col             := Get_Nat;
                        XE.Tref_Standard_Entity := No_Name;
                     end if;

                     --  ??? Temporary workaround for nested generics case:
                     --     4i4 Directories{1|4I9[4|6[3|3]]}
                     --  See C918-002

                     declare
                        Nested_Brackets : Natural := 0;

                     begin
                        loop
                           case Nextc is
                              when '['   =>
                                 Nested_Brackets := Nested_Brackets + 1;
                              when ']' =>
                                 Nested_Brackets := Nested_Brackets - 1;
                              when others =>
                                 if Nested_Brackets = 0 then
                                    exit;
                                 end if;
                           end case;

                           Skipc;
                        end loop;
                     end;

                     P := P + 1; -- skip closing bracket
                     Skip_Space;

                  --  No typeref entry present

                  else
                     XE.Tref_File_Num        := No_Sdep_Id;
                     XE.Tref_Line            := 0;
                     XE.Tref_Type            := ' ';
                     XE.Tref_Col             := 0;
                     XE.Tref_Standard_Entity := No_Name;
                  end if;

                  XE.First_Xref := Xref.Last + 1;

                  --  Loop through cross-references for this entity

                  loop
                     Skip_Space;

                     if At_Eol then
                        Skip_Eol;
                        exit when Nextc /= '.';
                        P := P + 1;
                     end if;

                     Xref.Increment_Last;

                     declare
                        XR : Xref_Record renames Xref.Table (Xref.Last);

                     begin
                        N := Get_Nat;

                        if Nextc = '|' then
                           XR.File_Num :=
                             Sdep_Id (N + Nat (First_Sdep_Entry) - 1);
                           Current_File_Num := XR.File_Num;
                           P := P + 1;
                           N := Get_Nat;
                        else
                           XR.File_Num := Current_File_Num;
                        end if;

                        XR.Line  := N;
                        XR.Rtype := Getc;

                        --  Imported entities reference as in:
                        --    494b<c,__gnat_copy_attribs>25
                        --  ??? Simply skipped for now

                        if Nextc = '<' then
                           while Getc /= '>' loop
                              null;
                           end loop;
                        end if;

                        XR.Col   := Get_Nat;

                        if Nextc = '[' then
                           Read_Instantiation_Reference;
                        end if;
                     end;
                  end loop;

                  --  Record last cross-reference

                  XE.Last_Xref := Xref.Last;
                  C := Nextc;
               end Read_Refs_For_One_Entity;
            end loop;

            --  Record last entity

            XS.Last_Entity := Xref_Entity.Last;

         end Read_Refs_For_One_File;

         C := Getc;
      end loop X_Loop;

      --  Here after dealing with xref sections

      if C /= EOF and then C /= 'X' then
         Fatal_Error;
      end if;

      return Id;

   exception
      when Bad_ALI_Format =>
         return No_ALI_Id;

   end Scan_ALI;

   ---------
   -- SEq --
   ---------

   function SEq (F1, F2 : String_Ptr) return Boolean is
   begin
      return F1.all = F2.all;
   end SEq;

   -----------
   -- SHash --
   -----------

   function SHash (S : String_Ptr) return Vindex is
      H : Word;

   begin
      H := 0;
      for J in S.all'Range loop
         H := H * 2 + Character'Pos (S (J));
      end loop;

      return Vindex (Vindex'First + Vindex (H mod Vindex'Range_Length));
   end SHash;

end ALI;