path: root/gcc/ada/lib-writ.adb

------------------------------------------------------------------------------
--                                                                          --
--                         GNAT COMPILER COMPONENTS                         --
--                                                                          --
--                             L I B . W R I T                              --
--                                                                          --
--                                 B o d y                                  --
--                                                                          --
--                                                                          --
--          Copyright (C) 1992-2001 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 ALI;      use ALI;
with Atree;    use Atree;
with Casing;   use Casing;
with Einfo;    use Einfo;
with Errout;   use Errout;
with Fname;    use Fname;
with Fname.UF; use Fname.UF;
with Lib.Util; use Lib.Util;
with Lib.Xref; use Lib.Xref;
with Namet;    use Namet;
with Nlists;   use Nlists;
with Gnatvsn;  use Gnatvsn;
with Opt;      use Opt;
with Osint;    use Osint;
with Osint.C;  use Osint.C;
with Par;
with Restrict; use Restrict;
with Scn;      use Scn;
with Sinfo;    use Sinfo;
with Sinput;   use Sinput;
with Stringt;  use Stringt;
with Uname;    use Uname;

with System.WCh_Con; use System.WCh_Con;

package body Lib.Writ is

   ------------------------------
   -- Ensure_System_Dependency --
   ------------------------------

   procedure Ensure_System_Dependency is
      Discard : List_Id;

      System_Uname : Unit_Name_Type;
      --  Unit name for system spec if needed for dummy entry

      System_Fname : File_Name_Type;
      --  File name for system spec if needed for dummy entry

   begin
      --  Nothing to do if we already compiled System

      for Unum in Units.First .. Last_Unit loop
         if Units.Table (Unum).Source_Index = System_Source_File_Index then
            return;
         end if;
      end loop;

      --  If no entry for system.ads in the units table, then add a entry
      --  to the units table for system.ads, which will be referenced when
      --  the ali file is generated. We need this because every unit depends
      --  on system as a result of Targparm scanning the system.ads file to
      --  determine the target dependent parameters for the compilation.

      Name_Len := 6;
      Name_Buffer (1 .. 6) := "system";
      System_Uname := Name_To_Unit_Name (Name_Enter);
      System_Fname := File_Name (System_Source_File_Index);

      Units.Increment_Last;
      Units.Table (Units.Last) := (
        Unit_File_Name  => System_Fname,
        Unit_Name       => System_Uname,
        Expected_Unit   => System_Uname,
        Source_Index    => System_Source_File_Index,
        Cunit           => Empty,
        Cunit_Entity    => Empty,
        Dependency_Num  => 0,
        Dependent_Unit  => True,
        Dynamic_Elab    => False,
        Fatal_Error     => False,
        Generate_Code   => False,
        Has_RACW        => False,
        Ident_String    => Empty,
        Loading         => False,
        Main_Priority   => -1,
        Serial_Number   => 0,
        Version         => 0,
        Error_Location  => No_Location);

      --  Parse system.ads so that the checksum is set right

      Initialize_Scanner (Units.Last, System_Source_File_Index);
      Discard := Par (Configuration_Pragmas => False);
   end Ensure_System_Dependency;

   ---------------
   -- Write_ALI --
   ---------------

   procedure Write_ALI (Object : Boolean) is

      ----------------
      -- Local Data --
      ----------------

      Last_Unit : constant Unit_Number_Type := Units.Last;
      --  Record unit number of last unit. We capture this in case we
      --  have to add a dummy entry to the unit table for package System.

      With_Flags : array (Units.First .. Last_Unit) of Boolean;
      --  Array of flags to show which units are with'ed

      Elab_Flags : array (Units.First .. Last_Unit) of Boolean;
      --  Array of flags to show which units have pragma Elaborate set

      Elab_All_Flags : array (Units.First .. Last_Unit) of Boolean;
      --  Array of flags to show which units have pragma Elaborate All set

      Elab_Des_Flags : array (Units.First .. Last_Unit) of Boolean;
      --  Array of flags to show which units have Elaborate_All_Desirable set

      Sdep_Table : Unit_Ref_Table (1 .. Pos (Last_Unit - Units.First + 2));
      --  Sorted table of source dependencies. One extra entry in case we
      --  have to add a dummy entry for System.

      Num_Sdep : Nat := 0;
      --  Number of active entries in Sdep_Table

      -----------------------
      -- Local Subprograms --
      -----------------------

      procedure Collect_Withs (Cunit : Node_Id);
      --  Collect with lines for entries in the context clause of the
      --  given compilation unit, Cunit.

      procedure Update_Tables_From_ALI_File;
      --  Given an up to date ALI file (see Up_To_Date_ALI_file_Exists
      --  function), update tables from the ALI information, including
      --  specifically the Compilation_Switches table.

      function Up_To_Date_ALI_File_Exists return Boolean;
      --  If there exists an ALI file that is up to date, then this function
      --  initializes the tables in the ALI spec to contain information on
      --  this file (using Scan_ALI) and returns True. If no file exists,
      --  or the file is not up to date, then False is returned.

      procedure Write_Unit_Information (Unit_Num : Unit_Number_Type);
      --  Write out the library information for one unit for which code is
      --  generated (includes unit line and with lines).

      procedure Write_With_Lines;
      --  Write out with lines collected by calls to Collect_Withs

      -------------------
      -- Collect_Withs --
      -------------------

      procedure Collect_Withs (Cunit : Node_Id) is
         Item : Node_Id;
         Unum : Unit_Number_Type;

      begin
         Item := First (Context_Items (Cunit));
         while Present (Item) loop

            if Nkind (Item) = N_With_Clause then
               Unum := Get_Cunit_Unit_Number (Library_Unit (Item));
               With_Flags (Unum) := True;

               if Elaborate_Present (Item) then
                  Elab_Flags (Unum) := True;
               end if;

               if Elaborate_All_Present (Item) then
                  Elab_All_Flags (Unum) := True;
               end if;

               if Elaborate_All_Desirable (Cunit_Entity (Unum)) then
                  Elab_Des_Flags (Unum) := True;
               end if;
            end if;

            Next (Item);
         end loop;
      end Collect_Withs;

      --------------------------------
      -- Up_To_Date_ALI_File_Exists --
      --------------------------------

      function Up_To_Date_ALI_File_Exists return Boolean is
         Name : File_Name_Type;
         Text : Text_Buffer_Ptr;
         Id   : Sdep_Id;
         Sind : Source_File_Index;

      begin
         Opt.Check_Object_Consistency := True;
         Read_Library_Info (Name, Text);

         --  Return if we could not find an ALI file

         if Text = null then
            return False;
         end if;

         --  Return if ALI file has bad format

         Initialize_ALI;

         if Scan_ALI (Name, Text, False, Err => True) = No_ALI_Id then
            return False;
         end if;

         --  If we have an OK ALI file, check if it is up to date
         --  Note that we assume that the ALI read has all the entries
         --  we have in our table, plus some additional ones (that can
         --  come from expansion).

         Id := First_Sdep_Entry;
         for J in 1 .. Num_Sdep loop
            Sind := Units.Table (Sdep_Table (J)).Source_Index;

            while Sdep.Table (Id).Sfile /= File_Name (Sind) loop
               if Id = Sdep.Last then
                  return False;
               else
                  Id := Id + 1;
               end if;
            end loop;

            if Sdep.Table (Id).Stamp /= Time_Stamp (Sind) then
               return False;
            end if;
         end loop;

         return True;
      end Up_To_Date_ALI_File_Exists;

      ---------------------------------
      -- Update_Tables_From_ALI_File --
      ---------------------------------

      procedure Update_Tables_From_ALI_File is
      begin
         --  Build Compilation_Switches table

         Compilation_Switches.Init;

         for J in First_Arg_Entry .. Args.Last loop
            Compilation_Switches.Increment_Last;
            Compilation_Switches.Table (Compilation_Switches.Last) :=
              Args.Table (J);
         end loop;
      end Update_Tables_From_ALI_File;

      ----------------------------
      -- Write_Unit_Information --
      ----------------------------

      procedure Write_Unit_Information (Unit_Num : Unit_Number_Type) is
         Unode : constant Node_Id   := Cunit (Unit_Num);
         Ukind : constant Node_Kind := Nkind (Unit (Unode));
         Uent  : constant Entity_Id := Cunit_Entity (Unit_Num);
         Pnode : Node_Id;

      begin
         Write_Info_Initiate ('U');
         Write_Info_Char (' ');
         Write_Info_Name (Unit_Name (Unit_Num));
         Write_Info_Tab (25);
         Write_Info_Name (Unit_File_Name (Unit_Num));

         Write_Info_Tab (49);
         Write_Info_Str (Version_Get (Unit_Num));

         if Dynamic_Elab (Unit_Num) then
            Write_Info_Str (" DE");
         end if;

         --  We set the Elaborate_Body indication if either an explicit pragma
         --  was present, or if this is an instantiation. RM 12.3(20) requires
         --  that the body be immediately elaborated after the spec. We would
         --  normally do that anyway, but the EB we generate here ensures that
         --  this gets done even when we use the -p gnatbind switch.

         if Has_Pragma_Elaborate_Body (Uent)
           or else (Ukind = N_Package_Declaration
                     and then Is_Generic_Instance (Uent)
                     and then Present (Corresponding_Body (Unit (Unode))))
         then
            Write_Info_Str (" EB");
         end if;

         --  Now see if we should tell the binder that an elaboration entity
         --  is present, which must be reset to true during elaboration. We
         --  generate the indication if the following condition is met:

         --  If this is a spec ...

         if (Is_Subprogram (Uent)
               or else
             Ekind (Uent) = E_Package
               or else
             Is_Generic_Unit (Uent))

            --  and an elaboration entity was declared ...

            and then Present (Elaboration_Entity (Uent))

            --  and either the elaboration flag is required ...

            and then
              (Elaboration_Entity_Required (Uent)

               --  or this unit has elaboration code ...

               or else not Has_No_Elaboration_Code (Unode)

               --  or this unit has a separate body and this
               --  body has elaboration code.

               or else
                 (Ekind (Uent) = E_Package
                   and then Present (Body_Entity (Uent))
                   and then
                     not Has_No_Elaboration_Code
                           (Parent
                             (Declaration_Node
                               (Body_Entity (Uent))))))
         then
            Write_Info_Str (" EE");
         end if;

         if Has_No_Elaboration_Code (Unode) then
            Write_Info_Str (" NE");
         end if;

         if Is_Preelaborated (Uent) then
            Write_Info_Str (" PR");
         end if;

         if Is_Pure (Uent) then
            Write_Info_Str (" PU");
         end if;

         if Has_RACW (Unit_Num) then
            Write_Info_Str (" RA");
         end if;

         if Is_Remote_Call_Interface (Uent) then
            Write_Info_Str (" RC");
         end if;

         if Is_Remote_Types (Uent) then
            Write_Info_Str (" RT");
         end if;

         if Is_Shared_Passive (Uent) then
            Write_Info_Str (" SP");
         end if;

         if Ukind = N_Subprogram_Declaration
           or else Ukind = N_Subprogram_Body
         then
            Write_Info_Str (" SU");

         elsif Ukind = N_Package_Declaration
                 or else
               Ukind = N_Package_Body
         then
            --  If this is a wrapper package for a subprogram instantiation,
            --  the user view is the subprogram. Note that in this case the
            --  ali file contains both the spec and body of the instance.

            if Is_Wrapper_Package (Uent) then
               Write_Info_Str (" SU");
            else
               Write_Info_Str (" PK");
            end if;

         elsif Ukind = N_Generic_Package_Declaration then
            Write_Info_Str (" PK");

         end if;

         if Ukind in N_Generic_Declaration
           or else
             (Present (Library_Unit (Unode))
                and then
              Nkind (Unit (Library_Unit (Unode))) in N_Generic_Declaration)
         then
            Write_Info_Str (" GE");
         end if;

         if not Is_Internal_File_Name (Unit_File_Name (Unit_Num), True) then
            case Identifier_Casing (Source_Index (Unit_Num)) is
               when All_Lower_Case => Write_Info_Str (" IL");
               when All_Upper_Case => Write_Info_Str (" IU");
               when others         => null;
            end case;

            case Keyword_Casing (Source_Index (Unit_Num)) is
               when Mixed_Case     => Write_Info_Str (" KM");
               when All_Upper_Case => Write_Info_Str (" KU");
               when others         => null;
            end case;
         end if;

         if Initialize_Scalars then
            Write_Info_Str (" IS");
         end if;

         Write_Info_EOL;

         --  Generate with lines, first those that are directly with'ed

         for J in With_Flags'Range loop
            With_Flags (J) := False;
            Elab_Flags (J) := False;
            Elab_All_Flags (J) := False;
            Elab_Des_Flags (J) := False;
         end loop;

         Collect_Withs (Unode);

         --  For a body, we must also check for any subunits which belong to
         --  it and which have context clauses of their own, since these
         --  with'ed units are part of its own elaboration dependencies.

         if Nkind (Unit (Unode)) in N_Unit_Body then
            for S in Units.First .. Last_Unit loop

               --  We are only interested in subunits

               if Nkind (Unit (Cunit (S))) = N_Subunit then
                  Pnode := Library_Unit (Cunit (S));

                  --  In gnatc mode, the errors in the subunits will not
                  --  have been recorded, but the analysis of the subunit
                  --  may have failed. There is no information to add to
                  --  ALI file in this case.

                  if No (Pnode) then
                     exit;
                  end if;

                  --  Find ultimate parent of the subunit

                  while Nkind (Unit (Pnode)) = N_Subunit loop
                     Pnode := Library_Unit (Pnode);
                  end loop;

                  --  See if it belongs to current unit, and if so, include
                  --  its with_clauses.

                  if Pnode = Unode then
                     Collect_Withs (Cunit (S));
                  end if;
               end if;
            end loop;
         end if;

         Write_With_Lines;

         --  Output linker option lines

         for J in 1 .. Linker_Option_Lines.Last loop
            declare
               S : constant Linker_Option_Entry :=
                     Linker_Option_Lines.Table (J);
               C : Character;

            begin
               if S.Unit = Unit_Num then
                  Write_Info_Initiate ('L');
                  Write_Info_Str (" """);

                  for J in 1 .. String_Length (S.Option) loop
                     C := Get_Character (Get_String_Char (S.Option, J));

                     if C in Character'Val (16#20#) .. Character'Val (16#7E#)
                       and then C /= '{'
                     then
                        Write_Info_Char (C);

                        if C = '"' then
                           Write_Info_Char (C);
                        end if;

                     else
                        declare
                           Hex : array (0 .. 15) of Character :=
                                   "0123456789ABCDEF";

                        begin
                           Write_Info_Char ('{');
                           Write_Info_Char (Hex (Character'Pos (C) / 16));
                           Write_Info_Char (Hex (Character'Pos (C) mod 16));
                           Write_Info_Char ('}');
                        end;
                     end if;
                  end loop;

                  Write_Info_Char ('"');
                  Write_Info_EOL;
               end if;
            end;
         end loop;
      end Write_Unit_Information;

      ----------------------
      -- Write_With_Lines --
      ----------------------

      procedure Write_With_Lines is
         With_Table : Unit_Ref_Table (1 .. Pos (Last_Unit - Units.First + 1));
         Num_Withs  : Int := 0;
         Unum       : Unit_Number_Type;
         Cunit      : Node_Id;
         Cunite     : Entity_Id;
         Uname      : Unit_Name_Type;
         Fname      : File_Name_Type;
         Pname      : constant Unit_Name_Type :=
                        Get_Parent_Spec_Name (Unit_Name (Main_Unit));
         Body_Fname : File_Name_Type;

      begin
         --  Loop to build the with table. A with on the main unit itself
         --  is ignored (AARM 10.2(14a)). Such a with-clause can occur if
         --  the main unit is a subprogram with no spec, and a subunit of
         --  it unecessarily withs the parent.

         for J in Units.First + 1 .. Last_Unit loop

            --  Add element to with table if it is with'ed or if it is the
            --  parent spec of the main unit (case of main unit is a child
            --  unit). The latter with is not needed for semantic purposes,
            --  but is required by the binder for elaboration purposes.

            if (With_Flags (J) or else Unit_Name (J) = Pname)
              and then Units.Table (J).Dependent_Unit
            then
               Num_Withs := Num_Withs + 1;
               With_Table (Num_Withs) := J;
            end if;
         end loop;

         --  Sort and output the table

         Sort (With_Table (1 .. Num_Withs));

         for J in 1 .. Num_Withs loop
            Unum   := With_Table (J);
            Cunit  := Units.Table (Unum).Cunit;
            Cunite := Units.Table (Unum).Cunit_Entity;
            Uname  := Units.Table (Unum).Unit_Name;
            Fname  := Units.Table (Unum).Unit_File_Name;

            Write_Info_Initiate ('W');
            Write_Info_Char (' ');
            Write_Info_Name (Uname);

            --  Now we need to figure out the names of the files that contain
            --  the with'ed unit. These will usually be the files for the body,
            --  except in the case of a package that has no body.

            if (Nkind (Unit (Cunit)) not in N_Generic_Declaration
                  and then
                Nkind (Unit (Cunit)) not in N_Generic_Renaming_Declaration)
              or else Generic_Separately_Compiled (Cunite)
            then
               Write_Info_Tab (25);

               if Is_Spec_Name (Uname) then
                  Body_Fname :=
                    Get_File_Name (Get_Body_Name (Uname), Subunit => False);
               else
                  Body_Fname := Get_File_Name (Uname, Subunit => False);
               end if;

               --  A package is considered to have a body if it requires
               --  a body or if a body is present in Ada 83 mode.

               if Body_Required (Cunit)
                 or else (Ada_83
                           and then Full_Source_Name (Body_Fname) /= No_File)
               then
                  Write_Info_Name (Body_Fname);
                  Write_Info_Tab (49);
                  Write_Info_Name (Lib_File_Name (Body_Fname));
               else
                  Write_Info_Name (Fname);
                  Write_Info_Tab (49);
                  Write_Info_Name (Lib_File_Name (Fname));
               end if;

               if Elab_Flags (Unum) then
                  Write_Info_Str ("  E");
               end if;

               if Elab_All_Flags (Unum) then
                  Write_Info_Str ("  EA");
               end if;

               if Elab_Des_Flags (Unum) then
                  Write_Info_Str ("  ED");
               end if;
            end if;

            Write_Info_EOL;
         end loop;
      end Write_With_Lines;

   --  Start of processing for Writ_ALI

   begin
      --  Build sorted source dependency table. We do this right away,
      --  because it is referenced by Up_To_Date_ALI_File_Exists.

      for Unum in Units.First .. Last_Unit loop
         Num_Sdep := Num_Sdep + 1;
         Sdep_Table (Num_Sdep) := Unum;
      end loop;

      --  Sort the table so that the D lines are in order

      Lib.Sort (Sdep_Table (1 .. Num_Sdep));

      --  If we are not generating code, and there is an up to date
      --  ali file accessible, read it, and acquire the compilation
      --  arguments from this file.

      if Operating_Mode /= Generate_Code then
         if Up_To_Date_ALI_File_Exists then
            Update_Tables_From_ALI_File;
            return;
         end if;
      end if;

      --  Otherwise acquire compilation arguments and prepare to write
      --  out a new ali file.

      Create_Output_Library_Info;

      --  Output version line

      Write_Info_Initiate ('V');
      Write_Info_Str (" """);
      Write_Info_Str (Library_Version);
      Write_Info_Char ('"');

      Write_Info_EOL;

      --  Output main program line if this is acceptable main program

      declare
         U : Node_Id := Unit (Units.Table (Main_Unit).Cunit);
         S : Node_Id;

         procedure M_Parameters;
         --  Output parameters for main program line

         procedure M_Parameters is
         begin
            if Main_Priority (Main_Unit) /= Default_Main_Priority then
               Write_Info_Char (' ');
               Write_Info_Nat (Main_Priority (Main_Unit));
            end if;

            if Opt.Time_Slice_Set then
               Write_Info_Str (" T=");
               Write_Info_Nat (Opt.Time_Slice_Value);
            end if;

            Write_Info_Str (" W=");
            Write_Info_Char
              (WC_Encoding_Letters (Wide_Character_Encoding_Method));

            Write_Info_EOL;
         end M_Parameters;

      begin
         if Nkind (U) = N_Subprogram_Body
           or else (Nkind (U) = N_Package_Body
                      and then
                        (Nkind (Original_Node (U)) = N_Function_Instantiation
                           or else
                         Nkind (Original_Node (U)) =
                                                  N_Procedure_Instantiation))
         then
            --  If the unit is a subprogram instance, the entity for the
            --  subprogram is the alias of the visible entity, which is the
            --  related instance of the wrapper package. We retrieve the
            --  subprogram declaration of the desired entity.

            if Nkind (U) = N_Package_Body then
               U := Parent (Parent (
                   Alias (Related_Instance (Defining_Unit_Name
                     (Specification (Unit (Library_Unit (Parent (U)))))))));
            end if;

            S := Specification (U);

            if not Present (Parameter_Specifications (S)) then
               if Nkind (S) = N_Procedure_Specification then
                  Write_Info_Initiate ('M');
                  Write_Info_Str (" P");
                  M_Parameters;

               else
                  declare
                     Nam : Node_Id := Defining_Unit_Name (S);

                  begin
                     --  If it is a child unit, get its simple name.

                     if Nkind (Nam) = N_Defining_Program_Unit_Name then
                        Nam := Defining_Identifier (Nam);
                     end if;

                     if Is_Integer_Type (Etype (Nam)) then
                        Write_Info_Initiate ('M');
                        Write_Info_Str (" F");
                        M_Parameters;
                     end if;
                  end;
               end if;
            end if;
         end if;
      end;

      --  Write command argmument ('A') lines

      for A in 1 .. Compilation_Switches.Last loop
         Write_Info_Initiate ('A');
         Write_Info_Char (' ');
         Write_Info_Str (Compilation_Switches.Table (A).all);
         Write_Info_Terminate;
      end loop;

      --  Output parameters ('P') line

      Write_Info_Initiate ('P');

      if Compilation_Errors then
         Write_Info_Str (" CE");
      end if;

      if Opt.Float_Format /= ' ' then
         Write_Info_Str (" F");

         if Opt.Float_Format = 'I' then
            Write_Info_Char ('I');

         elsif Opt.Float_Format_Long = 'D' then
            Write_Info_Char ('D');

         else
            Write_Info_Char ('G');
         end if;
      end if;

      if Tasking_Used
        and then not Is_Predefined_File_Name (Unit_File_Name (Main_Unit))
      then
         if Locking_Policy /= ' ' then
            Write_Info_Str  (" L");
            Write_Info_Char (Locking_Policy);
         end if;

         if Queuing_Policy /= ' ' then
            Write_Info_Str  (" Q");
            Write_Info_Char (Queuing_Policy);
         end if;

         if Task_Dispatching_Policy /= ' ' then
            Write_Info_Str  (" T");
            Write_Info_Char (Task_Dispatching_Policy);
            Write_Info_Char (' ');
         end if;
      end if;

      if not Object then
         Write_Info_Str (" NO");
      end if;

      if No_Run_Time then
         Write_Info_Str (" NR");
      end if;

      if Normalize_Scalars then
         Write_Info_Str (" NS");
      end if;

      if Unreserve_All_Interrupts then
         Write_Info_Str (" UA");
      end if;

      if Exception_Mechanism /= Setjmp_Longjmp then
         if Unit_Exception_Table_Present then
            Write_Info_Str (" UX");
         end if;

         Write_Info_Str (" ZX");
      end if;

      Write_Info_EOL;

      --  Output restrictions line

      Write_Info_Initiate ('R');
      Write_Info_Char (' ');

      for J in All_Restrictions loop
         if Main_Restrictions (J) then
            Write_Info_Char ('r');
         elsif Violations (J) then
            Write_Info_Char ('v');
         else
            Write_Info_Char ('n');
         end if;
      end loop;

      Write_Info_EOL;

      --  Loop through file table to output information for all units for which
      --  we have generated code, as marked by the Generate_Code flag.

      for Unit in Units.First .. Last_Unit loop
         if Units.Table (Unit).Generate_Code
           or else Unit = Main_Unit
         then
            Write_Info_EOL; -- blank line
            Write_Unit_Information (Unit);
         end if;
      end loop;

      Write_Info_EOL; -- blank line

      --  Output external version reference lines

      for J in 1 .. Version_Ref.Last loop
         Write_Info_Initiate ('E');
         Write_Info_Char (' ');

         for K in 1 .. String_Length (Version_Ref.Table (J)) loop
            Write_Info_Char_Code (Get_String_Char (Version_Ref.Table (J), K));
         end loop;

         Write_Info_EOL;
      end loop;

      --  Prepare to output the source dependency lines

      declare
         Unum : Unit_Number_Type;
         --  Number of unit being output

         Sind : Source_File_Index;
         --  Index of corresponding source file

      begin
         for J in 1 .. Num_Sdep loop
            Unum := Sdep_Table (J);
            Units.Table (Unum).Dependency_Num := J;
            Sind := Units.Table (Unum).Source_Index;

            Write_Info_Initiate ('D');
            Write_Info_Char (' ');

            --  Normal case of a dependent unit entry with a source index

            if Sind /= No_Source_File
              and then Units.Table (Unum).Dependent_Unit
            then
               Write_Info_Name (File_Name (Sind));
               Write_Info_Tab (25);
               Write_Info_Str (String (Time_Stamp (Sind)));
               Write_Info_Char (' ');
               Write_Info_Str (Get_Hex_String (Source_Checksum (Sind)));

               --  If subunit, add unit name, omitting the %b at the end

               if Present (Cunit (Unum))
                 and then Nkind (Unit (Cunit (Unum))) = N_Subunit
               then
                  Get_Decoded_Name_String (Unit_Name (Unum));
                  Write_Info_Char (' ');
                  Write_Info_Str (Name_Buffer (1 .. Name_Len - 2));
               end if;

               --  If Source_Reference pragma used output information

               if Num_SRef_Pragmas (Sind) > 0 then
                  Write_Info_Char (' ');

                  if Num_SRef_Pragmas (Sind) = 1 then
                     Write_Info_Nat (Int (First_Mapped_Line (Sind)));
                  else
                     Write_Info_Nat (0);
                  end if;

                  Write_Info_Char (':');
                  Write_Info_Name (Reference_Name (Sind));
               end if;

            --  Case where there is no source index (happens for missing files)
            --  Also come here for non-dependent units.

            else
               Write_Info_Name (Unit_File_Name (Unum));
               Write_Info_Tab (25);
               Write_Info_Str (String (Dummy_Time_Stamp));
               Write_Info_Char (' ');
               Write_Info_Str (Get_Hex_String (0));
            end if;

            Write_Info_EOL;
         end loop;
      end;

      Output_References;
      Write_Info_Terminate;
      Close_Output_Library_Info;

   end Write_ALI;

end Lib.Writ;