------------------------------------------------------------------------------
--                                                                          --
--                           GPR PROJECT MANAGER                            --
--                                                                          --
--          Copyright (C) 2000-2022, Free Software Foundation, Inc.         --
--                                                                          --
-- This library is free software;  you can redistribute it and/or modify it --
-- under terms of the  GNU General Public License  as published by the Free --
-- Software  Foundation;  either version 3,  or (at your  option) any later --
-- version. This library is distributed in the hope that it will be useful, --
-- but WITHOUT ANY WARRANTY;  without even the implied warranty of MERCHAN- --
-- TABILITY or FITNESS FOR A PARTICULAR PURPOSE.                            --
--                                                                          --
-- As a special exception under Section 7 of GPL version 3, you are granted --
-- additional permissions described in the GCC Runtime Library Exception,   --
-- version 3.1, as published by the Free Software Foundation.               --
--                                                                          --
-- You should have received a copy of the GNU General Public License and    --
-- a copy of the GCC Runtime Library Exception along with this program;     --
-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
-- <http://www.gnu.org/licenses/>.                                          --
--                                                                          --
------------------------------------------------------------------------------

with Ada;                        use Ada;
with Ada.Characters.Handling;    use Ada.Characters.Handling;
with Ada.Directories;            use Ada.Directories;
with Ada.Strings;                use Ada.Strings;
with Ada.Strings.Fixed;          use Ada.Strings.Fixed;
with Ada.Strings.Maps.Constants; use Ada.Strings.Maps.Constants;
with Ada.Text_IO;                use Ada.Text_IO;

with Ada.Containers.Hashed_Maps;
with Ada.Containers.Indefinite_Vectors;
with Ada.Strings.Hash_Case_Insensitive;
with Ada.Strings.Equal_Case_Insensitive;

with GNAT.Directory_Operations; use GNAT.Directory_Operations;
with GNAT.Dynamic_HTables;
with GNAT.Regexp;               use GNAT.Regexp;
with GNAT.Table;

with GPR.Com;
with GPR.Debug;
with GPR.Env;     use GPR.Env;
with GPR.Err;     use GPR.Err;
with GPR.Erroutc; use GPR.Erroutc;
with GPR.Names;   use GPR.Names;
with GPR.Opt;     use GPR.Opt;
with GPR.Osint;   use GPR.Osint;
with GPR.Output;  use GPR.Output;
with GPR.Sinput;  use GPR.Sinput;
with GPR.Tree;    use GPR.Tree;
with GPR.Util;    use GPR.Util;
with GPR.Snames;  use GPR.Snames;

package body GPR.Nmsc is

   No_Continuation_String : aliased String := "";
   Continuation_String    : aliased String := "\";
   --  Used in Check_Library for continuation error messages at the same
   --  location.

   type Name_Location is record
      Name     : File_Name_Type;
      --  Key is duplicated, so that it is known when using functions Get_First
      --  and Get_Next, as these functions only return an Element.

      Location : Source_Ptr;
      Source   : Source_Id := No_Source;
      Listed   : Boolean := False;
      Found    : Boolean := False;
   end record;

   No_Name_Location : constant Name_Location :=
                        (Name     => No_File,
                         Location => No_Location,
                         Source   => No_Source,
                         Listed   => False,
                         Found    => False);

   package Source_Names_Htable is new GNAT.Dynamic_HTables.Simple_HTable
     (Header_Num => Header_Num,
      Element    => Name_Location,
      No_Element => No_Name_Location,
      Key        => File_Name_Type,
      Hash       => Hash,
      Equal      => "=");
   --  File name information found in string list attribute (Source_Files or
   --  Source_List_File). Used to check that all referenced files were indeed
   --  found on the disk.

   type Unit_Exception is record
      Name : Name_Id;
      --  Key is duplicated, so that it is known when using functions Get_First
      --  and Get_Next, as these functions only return an Element.

      Spec : File_Name_Type;
      Impl : File_Name_Type;
   end record;

   No_Unit_Exception : constant Unit_Exception := (No_Name, No_File, No_File);

   package Unit_Exceptions_Htable is new GNAT.Dynamic_HTables.Simple_HTable
     (Header_Num => Header_Num,
      Element    => Unit_Exception,
      No_Element => No_Unit_Exception,
      Key        => Name_Id,
      Hash       => Hash,
      Equal      => "=");
   --  Record special naming schemes for Ada units (name of spec file and name
   --  of implementation file). The elements in this list come from the naming
   --  exceptions specified in the project files.

   type File_Found is record
      File      : File_Name_Type := No_File;
      Excl_File : File_Name_Type := No_File;
      Excl_Line : Natural        := 0;
      Found     : Boolean        := False;
      Location  : Source_Ptr     := No_Location;
      Project   : Project_Id     := No_Project;
   end record;

   No_File_Found : constant File_Found :=
                     (No_File, No_File, 0, False, No_Location, No_Project);

   package Excluded_Sources_Htable is new GNAT.Dynamic_HTables.Simple_HTable
     (Header_Num => Header_Num,
      Element    => File_Found,
      No_Element => No_File_Found,
      Key        => File_Name_Type,
      Hash       => Hash,
      Equal      => "=");
   --  A hash table to store the base names of excluded files, if any

   package Object_File_Names_Htable is new GNAT.Dynamic_HTables.Simple_HTable
     (Header_Num => Header_Num,
      Element    => Source_Id,
      No_Element => No_Source,
      Key        => File_Name_Type,
      Hash       => Hash,
      Equal      => "=");
   --  A hash table to store the object file names for a project, to check that
   --  two different sources have different object file names.

   type Project_Processing_Data is record
      Project         : Project_Id;
      Source_Names    : Source_Names_Htable.Instance;
      Unit_Exceptions : Unit_Exceptions_Htable.Instance;
      Excluded        : Excluded_Sources_Htable.Instance;

      Source_List_File_Location : Source_Ptr;
      --  Location of the Source_List_File attribute, for error messages
   end record;
   --  This is similar to Tree_Processing_Data, but contains project-specific
   --  information which is only useful while processing the project, and can
   --  be discarded as soon as we have finished processing the project

   type Tree_Processing_Data is record
      Tree             : Project_Tree_Ref;
      Node_Tree        : GPR.Tree.Project_Node_Tree_Ref;
      Flags            : GPR.Processing_Flags;
      In_Aggregate_Lib : Boolean;
   end record;
   --  Temporary data which is needed while parsing a project. It does not need
   --  to be kept in memory once a project has been fully loaded, but is
   --  necessary while performing consistency checks (duplicate sources,...)
   --  This data must be initialized before processing any project, and the
   --  same data is used for processing all projects in the tree.

   type Lib_Data is record
      Name : Name_Id;
      Proj : Project_Id;
      Tree : Project_Tree_Ref;
   end record;

   package Lib_Data_Table is new GNAT.Table
     (Table_Component_Type => Lib_Data,
      Table_Index_Type     => Natural,
      Table_Low_Bound      => 1,
      Table_Initial        => 10,
      Table_Increment      => 100);
   --  A table to record library names in order to check that two library
   --  projects do not have the same library names.

   type Error_Message (Length : Positive) is record
      Flags    : Processing_Flags;
      Location : Source_Ptr;
      Project  : Project_Id;
      Msg      : String (1 .. Length);
   end record;

   package Hold_Errors is new Ada.Containers.Indefinite_Vectors
     (Positive, Error_Message);

   Errors_Holder : Hold_Errors.Vector;
   --  Keep error messages until decision is it error, warning or should be
   --  forgotten.

   procedure Initialize
     (Data      : out Tree_Processing_Data;
      Tree      : Project_Tree_Ref;
      Node_Tree : GPR.Tree.Project_Node_Tree_Ref;
      Flags     : GPR.Processing_Flags);
   --  Initialize Data

   procedure Free (Data : in out Tree_Processing_Data);
   --  Free the memory occupied by Data

   procedure Initialize
     (Data    : in out Project_Processing_Data;
      Project : Project_Id);
   procedure Free (Data : in out Project_Processing_Data);
   --  Initialize or free memory for a project-specific data

   procedure Find_Excluded_Sources
     (Project : in out Project_Processing_Data;
      Data    : in out Tree_Processing_Data);
   --  Find the list of files that should not be considered as source files
   --  for this project. Sets the list in the Project.Excluded_Sources_Htable.

   procedure Override_Kind (Source : Source_Id; Kind : Source_Kind);
   --  Override the reference kind for a source file. This properly updates
   --  the unit data if necessary.

   procedure Load_Naming_Exceptions
     (Project : in out Project_Processing_Data;
      Data    : in out Tree_Processing_Data);
   --  All source files in Data.First_Source are considered as naming
   --  exceptions, and copied into the Source_Names and Unit_Exceptions tables
   --  as appropriate.

   type Search_Type is (Search_Project_Files, Search_Source_Directories);
   --  Search_Project_Files is to find project files.
   --  Search_Source_Directories is to find source directories.

   procedure Expand_Subdirectory_Pattern
     (Project       : Project_Id;
      Data          : in out Tree_Processing_Data;
      Patterns      : String_List_Id;
      Ignore        : String_List_Id;
      Search_For    : Search_Type;
      Resolve_Links : Boolean;
      Callback      : access procedure
        (Path : Path_Information; Pattern_Index : Natural));
   --  Search the subdirectories of Project's directory for files or
   --  directories that match the globbing patterns found in Patterns (for
   --  instance "**/*.adb"). Typically, Patterns will be the value of the
   --  Source_Dirs or Excluded_Source_Dirs attributes.
   --
   --  Every time such a file or directory is found, the callback is called.
   --  Resolve_Links indicates whether we should resolve links while
   --  normalizing names.
   --
   --  In the callback, Pattern_Index is the index within Patterns where the
   --  expanded pattern was found (1 for the first element of Patterns and
   --  all its matching directories, then 2,...).
   --
   --  We use a generic and not an access-to-subprogram because in some cases
   --  this code is compiled with the restriction No_Implicit_Dynamic_Code.
   --  An error message is raised if a pattern does not match any file.

   procedure Add_Source
     (Id                  : out Source_Id;
      Data                : in out Tree_Processing_Data;
      Project             : Project_Id;
      Source_Dir_Rank     : Natural;
      Lang_Id             : Language_Ptr;
      Kind                : Source_Kind;
      File_Name           : File_Name_Type;
      Display_File        : File_Name_Type;
      Naming_Exception    : Naming_Exception_Type := No;
      Path                : Path_Information      := No_Path_Information;
      Alternate_Languages : Language_List         := null;
      Unit                : Name_Id               := No_Name;
      Index               : Int                   := 0;
      Locally_Removed     : Boolean               := False;
      Location            : Source_Ptr            := No_Location);
   --  Add a new source to the different lists: list of all sources in the
   --  project tree, list of source of a project and list of sources of a
   --  language. If Path is specified, the file is also added to
   --  Source_Paths_HT. Location is used for error messages

   function Canonical_Case_File_Name (Name : Name_Id) return File_Name_Type;
   --  Same as Osint.Canonical_Case_File_Name but applies to Name_Id.
   --  This alters Name_Buffer.

   function Suffix_Matches
     (Filename : String;
      Suffix   : File_Name_Type) return Boolean;
   --  True if the file name ends with the given suffix. Always returns False
   --  if Suffix is No_Name.

   procedure Replace_Into_Name_Buffer
     (Str         : String;
      Pattern     : String;
      Replacement : Character);
   --  Copy Str into Name_Buffer, replacing Pattern with Replacement. Str is
   --  converted to lower-case at the same time.

   procedure Check_Abstract_Project
     (Project : Project_Id;
      Data    : in out Tree_Processing_Data);
   --  Check abstract projects attributes

   procedure Check_Configuration
     (Project : Project_Id;
      Data    : in out Tree_Processing_Data);
   --  Check the configuration attributes for the project

   procedure Check_If_Externally_Built
     (Project : Project_Id;
      Data    : in out Tree_Processing_Data);
   --  Check attribute Externally_Built of project Project in project tree
   --  Data.Tree and modify its data Data if it has the value "true".

   procedure Check_Interfaces
     (Project : Project_Id;
      Data    : in out Tree_Processing_Data);
   --  If a list of sources is specified in attribute Interfaces, set
   --  In_Interfaces only for the sources specified in the list.

   procedure Check_Library_Attributes
     (Project    : Project_Id;
      No_Sources : Boolean;
      Data       : in out Tree_Processing_Data);
   --  Check the library attributes of project Project in project tree
   --  and modify its data Data accordingly. If the declared library attributes
   --  makes the project a library project, report an error when No_Sources
   --  is True.

   procedure Check_Package_Naming
     (Project : Project_Id;
      Data    : in out Tree_Processing_Data);
   --  Check the naming scheme part of Data, and initialize the naming scheme
   --  data in the config of the various languages.

   procedure Check_Programming_Languages
     (Project : Project_Id;
      Data    : in out Tree_Processing_Data);
   --  Check attribute Languages for the project with data Data in project
   --  tree Data.Tree and set the components of Data for all the programming
   --  languages indicated in attribute Languages, if any.

   procedure Check_Stand_Alone_Library
     (Project : Project_Id;
      Data    : in out Tree_Processing_Data);
   --  Check if project Project in project tree Data.Tree is a Stand-Alone
   --  Library project, and modify its data Data accordingly if it is one.

   procedure Check_Unit_Name (Name : String; Unit : out Name_Id);
   --  Check that a name is a valid unit name

   function Compute_Directory_Last (Dir : String) return Natural;
   --  Return the index of the last significant character in Dir. This is used
   --  to avoid duplicate '/' (slash) characters at the end of directory names.

   procedure Search_Directories
     (Project         : in out Project_Processing_Data;
      Data            : in out Tree_Processing_Data;
      For_All_Sources : Boolean);
   --  Search the source directories to find the sources. If For_All_Sources is
   --  True, check each regular file name against the naming schemes of the
   --  various languages. Otherwise consider only the file names in hash table
   --  Source_Names. If Allow_Duplicate_Basenames then files with identical
   --  base names are permitted within a project for source-based languages
   --  (never for unit based languages).

   procedure Check_File
     (Project           : in out Project_Processing_Data;
      Data              : in out Tree_Processing_Data;
      Source_Dir_Rank   : Natural;
      Path              : Path_Name_Type;
      Display_Path      : Path_Name_Type;
      File_Name         : File_Name_Type;
      Display_File_Name : File_Name_Type;
      Locally_Removed   : Boolean;
      For_All_Sources   : Boolean);
   --  Check if file File_Name is a valid source of the project. This is used
   --  in multi-language mode only. When the file matches one of the naming
   --  schemes, it is added to various htables through Add_Source and to
   --  Source_Paths_Htable.
   --
   --  File_Name is the same as Display_File_Name, but has been normalized.
   --  They do not include the directory information.
   --
   --  Path and Display_Path on the other hand are the full path to the file.
   --  Path must have been normalized (canonical casing and possibly links
   --  resolved).
   --
   --  Source_Directory is the directory in which the file was found. It is
   --  neither normalized nor has had links resolved, and must not end with a
   --  a directory separator, to avoid duplicates later on.
   --
   --  If For_All_Sources is True, then all possible file names are analyzed
   --  otherwise only those currently set in the Source_Names hash table.

   procedure Check_File_Naming_Schemes
     (Project               : Project_Processing_Data;
      File_Name             : File_Name_Type;
      Alternate_Languages   : out Language_List;
      Language              : out Language_Ptr;
      Display_Language_Name : out Name_Id;
      Unit                  : out Name_Id;
      Lang_Kind             : out Language_Kind;
      Kind                  : out Source_Kind);
   --  Check if the file name File_Name conforms to one of the naming schemes
   --  of the project. If the file does not match one of the naming schemes,
   --  set Language to No_Language_Index. Filename is the name of the file
   --  being investigated. It has been normalized (case-folded). File_Name is
   --  the same value.

   procedure Get_Object_Directory
     (Project    : Project_Id;
      Data       : in out Tree_Processing_Data;
      No_Sources : Boolean := False);
   --  Get the object directory of a project.

   procedure Get_Directories
     (Project    : Project_Id;
      Data       : in out Tree_Processing_Data;
      No_Sources : out Boolean);
   --  Get the object directory, the exec directory and the source directories
   --  of a project. Set No_Sources to True if there are no sources in the
   --  project and the project is not an extending project.

   procedure Get_Mains
     (Project : Project_Id;
      Data    : in out Tree_Processing_Data);
   --  Get the mains of a project from attribute Main, if it exists, and put
   --  them in the project data.

   procedure Get_Sources_From_File
     (Path     : String;
      Location : Source_Ptr;
      Project  : in out Project_Processing_Data;
      Data     : in out Tree_Processing_Data);
   --  Get the list of sources from a text file and put them in hash table
   --  Source_Names.

   procedure Find_Sources
     (Project : in out Project_Processing_Data;
      Data    : in out Tree_Processing_Data);
   --  Process the Source_Files and Source_List_File attributes, and store the
   --  list of source files into the Source_Names htable. When these attributes
   --  are not defined, find all files matching the naming schemes in the
   --  source directories. If Allow_Duplicate_Basenames, then files with the
   --  same base names are authorized within a project for source-based
   --  languages (never for unit based languages)

   procedure Compute_Unit_Name
     (File_Name : File_Name_Type;
      Naming    : Lang_Naming_Data;
      Kind      : out Source_Kind;
      Unit      : out Name_Id;
      Project   : Project_Processing_Data);
   --  Check whether the file matches the naming scheme. If it does,
   --  compute its unit name. If Unit is set to No_Name on exit, none of the
   --  other out parameters are relevant.

   procedure Check_Illegal_Suffix
     (Project         : Project_Id;
      Suffix          : File_Name_Type;
      Dot_Replacement : File_Name_Type;
      Attribute_Name  : String;
      Location        : Source_Ptr;
      Data            : in out Tree_Processing_Data);
   --  Display an error message if the given suffix is illegal for some reason.
   --  The name of the attribute we are testing is specified in Attribute_Name,
   --  which is used in the error message. Location is the location where the
   --  suffix is defined.

   procedure Locate_Directory
     (Project          : Project_Id;
      Name             : File_Name_Type;
      Path             : out Path_Information;
      Dir_Exists       : out Boolean;
      Data             : in out Tree_Processing_Data;
      Create           : String := "";
      Location         : Source_Ptr := No_Location;
      Must_Exist       : Boolean := True;
      Externally_Built : Boolean := False);
   --  Locate a directory. Name is the directory name. Relative paths are
   --  resolved relative to the project's directory. If the directory does
   --  not exist:
   --    - if Must_Exit is False, we return without checking for its existence
   --    - otherwise, if Create is a non-empty string, it might get created,
   --      following the behavior prescribed by Create_Dirs.
   --  In all cases, Dir_Exists indicates whether the directory now exists.
   --  Create is also used for debugging traces to show which path we are
   --  computing.

   procedure Look_For_Sources
     (Project : in out Project_Processing_Data;
      Data    : in out Tree_Processing_Data);
   --  Find all the sources of project Project in project tree Data.Tree and
   --  update its Data accordingly. This assumes that the special naming
   --  exceptions have already been processed.

   function Path_Name_Of
     (File_Name : File_Name_Type;
      Directory : Path_Name_Type) return String;
   --  Returns the path name of a (non project) file. Returns an empty string
   --  if file cannot be found.

   procedure Remove_Source
     (Tree        : Project_Tree_Ref;
      Id          : Source_Id;
      Replaced_By : Source_Id);
   --  Remove a file from the list of sources of a project. This might be
   --  because the file is replaced by another one in an extending project,
   --  or because a file was added as a naming exception but was not found
   --  in the end.

   procedure Report_No_Sources
     (Project      : Project_Id;
      Lang_Name    : String;
      Data         : Tree_Processing_Data;
      Location     : Source_Ptr;
      Continuation : Boolean := False);
   --  Report an error or a warning depending on the value of When_No_Sources
   --  when there are no sources for language Lang_Name.

   procedure Show_Source_Dirs
     (Project : Project_Id;
      Shared  : Shared_Project_Tree_Data_Access);
   --  List all the source directories of a project

   procedure Write_Attr (Name, Value : String);
   --  Debug print a value for a specific property. Does nothing when not in
   --  debug mode

   procedure Error_Or_Warning
     (Flags    : Processing_Flags;
      Kind     : Error_Warning;
      Msg      : String;
      Location : Source_Ptr;
      Project  : Project_Id);
   --  Process a message depending on Kind.
   --  Error or Warning going to be printed.
   --  Silent going to be ignored.
   --  Decide_Later going to be kept until call to Messages_Decision,

   function No_Space_Img (N : Natural) return String;
   --  Image of a Natural without the initial space

   ----------------------
   -- Error_Or_Warning --
   ----------------------

   procedure Error_Or_Warning
     (Flags    : Processing_Flags;
      Kind     : Error_Warning;
      Msg      : String;
      Location : Source_Ptr;
      Project  : Project_Id) is
   begin
      case Kind is
         when Silent       => null;
         when Error        => Error_Msg (Flags, Msg, Location, Project);
         when Warning      => Error_Msg (Flags, "?" & Msg, Location, Project);
         when Decide_Later =>
            Errors_Holder.Append
              (Error_Message'(Msg'Length, Flags, Location, Project, Msg));
      end case;
   end Error_Or_Warning;

   -----------------------
   -- Messages_Decision --
   -----------------------

   procedure Messages_Decision (Kind : Decided_Message) is
   begin
      for M of Errors_Holder loop
         Error_Or_Warning (M.Flags, Kind, M.Msg, M.Location, M.Project);
      end loop;

      Errors_Holder.Clear;
   end Messages_Decision;

   ------------------------------
   -- Replace_Into_Name_Buffer --
   ------------------------------

   procedure Replace_Into_Name_Buffer
     (Str         : String;
      Pattern     : String;
      Replacement : Character)
   is
      Max : constant Integer := Str'Last - Pattern'Length + 1;
      J   : Positive;

   begin
      Name_Len := 0;

      J := Str'First;
      while J <= Str'Last loop
         Name_Len := Name_Len + 1;

         if J <= Max and then Str (J .. J + Pattern'Length - 1) = Pattern then
            Name_Buffer (Name_Len) := Replacement;
            J := J + Pattern'Length;
         else
            Name_Buffer (Name_Len) := To_Lower (Str (J));
            J := J + 1;
         end if;
      end loop;
   end Replace_Into_Name_Buffer;

   --------------------
   -- Suffix_Matches --
   --------------------

   function Suffix_Matches
     (Filename : String;
      Suffix   : File_Name_Type) return Boolean
   is
      Min_Prefix_Length : Natural := 0;

   begin
      if Suffix in No_File | Empty_File then
         return False;
      end if;

      declare
         Suf : String := Get_Name_String (Suffix);

      begin
         --  On non case-sensitive systems, use proper suffix casing

         Canonical_Case_File_Name (Suf);

         --  The file name must end with the suffix (which is not an extension)
         --  For instance a suffix "configure.in" must match a file with the
         --  same name. To avoid dummy cases, though, a suffix starting with
         --  '.' requires a file that is at least one character longer ('.cpp'
         --  should not match a file with the same name).

         if Suf (Suf'First) = '.' then
            Min_Prefix_Length := 1;
         end if;

         return Filename'Length >= Suf'Length + Min_Prefix_Length
           and then
             Filename (Filename'Last - Suf'Length + 1 .. Filename'Last) = Suf;
      end;
   end Suffix_Matches;

   ----------------
   -- Write_Attr --
   ----------------

   procedure Write_Attr (Name, Value : String) is
   begin
      if Current_Verbosity = High then
         Debug_Output (Name & " = """ & Value & '"');
      end if;
   end Write_Attr;

   ----------------
   -- Add_Source --
   ----------------

   procedure Add_Source
     (Id                  : out Source_Id;
      Data                : in out Tree_Processing_Data;
      Project             : Project_Id;
      Source_Dir_Rank     : Natural;
      Lang_Id             : Language_Ptr;
      Kind                : Source_Kind;
      File_Name           : File_Name_Type;
      Display_File        : File_Name_Type;
      Naming_Exception    : Naming_Exception_Type := No;
      Path                : Path_Information      := No_Path_Information;
      Alternate_Languages : Language_List         := null;
      Unit                : Name_Id               := No_Name;
      Index               : Int                   := 0;
      Locally_Removed     : Boolean               := False;
      Location            : Source_Ptr            := No_Location)
   is
      Config            : constant Language_Config := Lang_Id.Config;
      UData             : Unit_Index;
      Add_Src           : Boolean;
      Source            : Source_Id;
      Prev_Unit         : Unit_Index := No_Unit_Index;
      Source_To_Replace : Source_Id := No_Source;

      S_Or_B : Spec_Or_Body;

   begin
      --  Check if the same file name or unit is used in the prj tree

      Add_Src := True;

      if Kind = Sep then
         S_Or_B := Impl;
      else
         S_Or_B := Kind;
      end if;

      if Unit /= No_Name then
         Prev_Unit := Units_Htable.Get (Data.Tree.Units_HT, Unit);
      end if;

      if Prev_Unit /= No_Unit_Index
        and then Prev_Unit.File_Names (S_Or_B) /= null
      then
         --  Suspicious, we need to check later whether this is authorized

         Add_Src := False;
         Source := Prev_Unit.File_Names (S_Or_B);

      else
         Source := Source_Files_Htable.Get
           (Data.Tree.Source_Files_HT, File_Name);

         if Source /= No_Source and then Source.Index = Index then
            Add_Src := False;
         end if;
      end if;

      --  Always add the source if it is locally removed, to avoid incorrect
      --  duplicate checks.

      if Locally_Removed then
         Add_Src := True;

         --  A locally removed source may first replace a source in a project
         --  being extended.

         if Source /= No_Source
           and then Is_Extending (Project, Source.Project)
           and then Naming_Exception /= Inherited
         then
            Source_To_Replace := Source;
         end if;

      else
         --  Duplication of file/unit in same project is allowed if order of
         --  source directories is known, or if there is no compiler for the
         --  language.

         if Add_Src = False then
            Add_Src := True;

            if Project = Source.Project then
               if Prev_Unit = No_Unit_Index then
                  if Data.Flags.Allow_Duplicate_Basenames then
                     Add_Src := True;

                  elsif Lang_Id.Config.Compiler_Driver = Empty_File then
                     Add_Src := True;

                  elsif Source_Dir_Rank /= Source.Source_Dir_Rank then
                     Add_Src := False;

                  else
                     Error_Msg_File_1 := File_Name;
                     Error_Msg
                       (Data.Flags, "duplicate source file name {",
                        Location, Project);
                     Add_Src := False;
                  end if;

               else
                  if Source_Dir_Rank /= Source.Source_Dir_Rank then
                     Add_Src := False;

                     --  We might be seeing the same file through a different
                     --  path (for instance because of symbolic links).

                  elsif Source.Path.Name /= Path.Name then
                     if not Source.Duplicate_Unit then
                        Error_Msg_Name_1 := Unit;
                        Error_Msg
                          (Data.Flags, "\duplicate unit %%", Location,
                           Project);

                        if Verbose_Mode then
                           Error_Msg_Name_1 := Name_Id (Source.Path.Name);
                           Error_Msg (Data.Flags, "\   %%", Location, Project);
                           Error_Msg_Name_1 := Name_Id (Path.Name);
                           Error_Msg (Data.Flags, "\   %%", Location, Project);
                        end if;

                        Source.Duplicate_Unit := True;
                     end if;

                     Add_Src := False;
                  end if;
               end if;

               --  Do not allow the same unit name in different projects,
               --  except if one is extending the other.

               --  For a file based language, the same file name replaces a
               --  file in a project being extended, but it is allowed to have
               --  the same file name in unrelated projects.

            elsif Is_Extending (Project, Source.Project) then
               if not Locally_Removed and then Naming_Exception /= Inherited
               then
                  Source_To_Replace := Source;
               end if;

            elsif Prev_Unit /= No_Unit_Index
              and then Prev_Unit.File_Names (Kind) /= null
              and then not Source.Locally_Removed
              and then Source.Replaced_By = No_Source
              and then not Data.In_Aggregate_Lib
            then
               --  Path is set if this is a source we found on the disk, in
               --  which case we can provide more explicit error message. Path
               --  is unset when the source is added from one of the naming
               --  exceptions in the project.

               if Path /= No_Path_Information then
                  Error_Msg_Name_1 := Unit;
                  Error_Msg
                    (Data.Flags,
                     "unit %% cannot belong to several projects",
                     Location, Project);

                  Error_Msg_Name_1 := Project.Name;
                  Error_Msg_Name_2 := Name_Id (Path.Display_Name);
                  Error_Msg
                    (Data.Flags, "\  project %%, %%", Location, Project);

                  Error_Msg_Name_1 := Source.Project.Name;
                  Error_Msg_Name_2 := Name_Id (Source.Path.Display_Name);
                  Error_Msg
                    (Data.Flags, "\  project %%, %%", Location, Project);

               else
                  Error_Msg_Name_1 := Unit;
                  Error_Msg_Name_2 := Source.Project.Name;
                  Error_Msg
                    (Data.Flags, "unit %% already belongs to project %%",
                     Location, Project);
               end if;

               Add_Src := False;

            elsif not Source.Locally_Removed
              and then Source.Replaced_By = No_Source
              and then not Data.Flags.Allow_Duplicate_Basenames
              and then Lang_Id.Config.Kind = File_Based
              and then Source.Language.Config.Kind = File_Based
              and then not Data.In_Aggregate_Lib
            then

               if Path /= No_Path_Information
                 and then Path = Source.Path
               then
                  Error_Msg_Name_1 := Name_Id (Path.Display_Name);
                  Error_Msg_Name_2 := Source.Project.Name;
                  Error_Msg
                    (Data.Flags,
                     "%% is already a source of project %%",
                     Location,
                     Project);

                  Add_Src := False;
               else
                  Add_Src := True;
               end if;

            elsif not Source.Locally_Removed
              and then Source.Replaced_By /= No_Source
              and then not Data.Flags.Allow_Duplicate_Basenames
              and then Lang_Id.Config.Kind = Unit_Based
              and then Source.Language.Config.Kind = Unit_Based
              and then not Data.In_Aggregate_Lib
            then
               Error_Msg_File_1 := File_Name;
               Error_Msg_File_2 := File_Name_Type (Source.Project.Name);
               Error_Msg
                 (Data.Flags,
                  "{ is already a source of project {", Location, Project);

               --  Add the file anyway, to avoid further warnings like
               --  "language unknown".

               Add_Src := True;
            end if;
         end if;
      end if;

      if not Add_Src then
         return;
      end if;

      --  Add the new file

      Id := new Source_Data;

      if Current_Verbosity = High then
         Debug_Indent;
         Write_Str ("adding source File: ");
         Write_Str (Get_Name_String (Display_File));

         if Index /= 0 then
            Write_Str (" at" & Index'Img);
         end if;

         if Lang_Id.Config.Kind = Unit_Based then
            Write_Str (" Unit: ");

            --  ??? in gprclean, it seems we sometimes pass an empty Unit name
            --  (see test extended_projects).

            if Unit /= No_Name then
               Write_Str (Get_Name_String (Unit));
            end if;

            Write_Str (" Kind: ");
            Write_Str (Source_Kind'Image (Kind));
         end if;

         Write_Eol;
      end if;

      Id.Project             := Project;
      Id.Location            := Location;
      Id.Source_Dir_Rank     := Source_Dir_Rank;
      Id.Language            := Lang_Id;
      Id.Kind                := Kind;
      Id.Alternate_Languages := Alternate_Languages;
      Id.Locally_Removed     := Locally_Removed;
      Id.Index               := Index;
      Id.File                := File_Name;
      Id.Display_File        := Display_File;
      Id.Dep_Name            := Dependency_Name
                                  (File_Name, Lang_Id.Config.Dependency_Kind);
      Id.Naming_Exception    := Naming_Exception;
      Id.Object              := Object_Name
                                  (File_Name, Config.Object_File_Suffix);
      Id.Switches            := Switches_Name (File_Name);

      --  Add the source id to the Unit_Sources_HT hash table, if the unit name
      --  is not null.

      if Unit /= No_Name then

         --  Note: we might be creating a dummy unit here, when we in fact have
         --  a separate. For instance, file file-bar.adb will initially be
         --  assumed to be the IMPL of unit "file.bar". Only later on (in
         --  Check_Object_Files) will we parse those units that only have an
         --  impl and no spec to make sure whether we have a Separate in fact
         --  (that significantly reduces the number of times we need to parse
         --  the files, since we are then only interested in those with no
         --  spec). We still need those dummy units in the table, since that's
         --  the name we find in the ALI file

         UData := Units_Htable.Get (Data.Tree.Units_HT, Unit);

         if UData = No_Unit_Index then
            UData := new Unit_Data;
            UData.Name := Unit;

            if Naming_Exception /= Inherited then
               Units_Htable.Set (Data.Tree.Units_HT, Unit, UData);
            end if;
         end if;

         Id.Unit := UData;

         --  Note that this updates Unit information as well

         if Naming_Exception /= Inherited and then not Locally_Removed then
            Override_Kind (Id, Kind);
         end if;
      end if;

      if Path /= No_Path_Information then
         Id.Path := Path;
         Source_Paths_Htable.Set (Data.Tree.Source_Paths_HT, Path.Name, Id);
      end if;

      Id.Next_With_File_Name :=
        Source_Files_Htable.Get (Data.Tree.Source_Files_HT, File_Name);
      Source_Files_Htable.Set (Data.Tree.Source_Files_HT, File_Name, Id);

      if Index /= 0 then
         Project.Has_Multi_Unit_Sources := True;
      end if;

      --  Add the source to the language list

      Id.Next_In_Lang := Lang_Id.First_Source;
      Lang_Id.First_Source := Id;

      if Source_To_Replace /= No_Source then
         Remove_Source (Data.Tree, Source_To_Replace, Id);
      end if;

      if Data.Tree.Replaced_Source_Number > 0
        and then
          Replaced_Source_HTable.Get
            (Data.Tree.Replaced_Sources, Id.File) /= No_File
      then
         Replaced_Source_HTable.Remove (Data.Tree.Replaced_Sources, Id.File);
         Data.Tree.Replaced_Source_Number :=
           Data.Tree.Replaced_Source_Number - 1;
      end if;
   end Add_Source;

   ------------------------------
   -- Canonical_Case_File_Name --
   ------------------------------

   function Canonical_Case_File_Name (Name : Name_Id) return File_Name_Type is
   begin
      if Name = No_Name then
         return File_Name_Type (Name);
      else
         Get_Name_String (Name);
         Canonical_Case_File_Name (Name_Buffer (1 .. Name_Len));
         return Name_Find;
      end if;
   end Canonical_Case_File_Name;

   ---------------------------------
   -- Process_Aggregated_Projects --
   ---------------------------------

   procedure Process_Aggregated_Projects
     (Tree      : Project_Tree_Ref;
      Project   : Project_Id;
      Node_Tree : GPR.Tree.Project_Node_Tree_Ref;
      Flags     : Processing_Flags)
   is
      Data : Tree_Processing_Data :=
               (Tree             => Tree,
                Node_Tree        => Node_Tree,
                Flags            => Flags,
                In_Aggregate_Lib => False);

      Project_Files : constant GPR.Variable_Value :=
                        GPR.Util.Value_Of
                          (Snames.Name_Project_Files,
                           Project.Decl.Attributes,
                           Tree.Shared);

      Project_Path_For_Aggregate : GPR.Env.Project_Search_Path;

      procedure Found_Project_File (Path : Path_Information; Rank : Natural);
      --  Called for each project file aggregated by Project

      ------------------------
      -- Found_Project_File --
      ------------------------

      procedure Found_Project_File (Path : Path_Information; Rank : Natural) is
         pragma Unreferenced (Rank);

      begin
         if Path.Name /= Project.Path.Name then
            Debug_Output ("aggregates: ", Name_Id (Path.Display_Name));

            --  For usual "with" statement, this phase will have been done when
            --  parsing the project itself. However, for aggregate projects, we
            --  can only do this when processing the aggregate project, since
            --  the exact list of project files or project directories can
            --  depend on scenario variables.
            --
            --  We only load the projects explicitly here, but do not process
            --  them. For the processing, GPR.Proc will take care of
            --  processing them, within the same call to Recursive_Process
            --  (thus avoiding the processing of a given project multiple
            --  times).
            --
            --  ??? We might already have loaded the project

            Add_Aggregated_Project (Project, Path => Path.Display_Name);

         else
            Debug_Output ("pattern returned the aggregate itself, ignored");
         end if;
      end Found_Project_File;

   --  Start of processing for Check_Aggregate_Project

   begin
      pragma Assert (Project.Qualifier in Aggregate_Project);

      if Project_Files.Default then
         Error_Msg_Name_1 := Snames.Name_Project_Files;
         Error_Msg
           (Flags,
            "Attribute %% must be specified in aggregate project",
            Project.Location, Project);
         return;
      end if;

      --  The aggregated projects are only searched relative to the directory
      --  of the aggregate project, not in the default project path.

      Initialize_Empty (Project_Path_For_Aggregate);

      Free (Project.Aggregated_Projects);

      --  Look for aggregated projects. For similarity with source files and
      --  dirs, the aggregated project files are not searched for on the
      --  project path, and are only found through the path specified in
      --  the Project_Files attribute.

      Expand_Subdirectory_Pattern
        (Project       => Project,
         Data          => Data,
         Patterns      => Project_Files.Values,
         Ignore        => Nil_String,
         Search_For    => Search_Project_Files,
         Resolve_Links => Opt.Follow_Links_For_Files,
         Callback      => Found_Project_File'Access);

      Free (Project_Path_For_Aggregate);
   end Process_Aggregated_Projects;

   ----------------------------
   -- Check_Abstract_Project --
   ----------------------------

   procedure Check_Abstract_Project
     (Project : Project_Id;
      Data    : in out Tree_Processing_Data)
   is
      Shared : constant Shared_Project_Tree_Data_Access := Data.Tree.Shared;

      Source_Dirs      : constant Variable_Value :=
                           Util.Value_Of
                             (Name_Source_Dirs,
                              Project.Decl.Attributes, Shared);
      Source_Files     : constant Variable_Value :=
                           Util.Value_Of
                             (Name_Source_Files,
                              Project.Decl.Attributes, Shared);
      Source_List_File : constant Variable_Value :=
                           Util.Value_Of
                             (Name_Source_List_File,
                              Project.Decl.Attributes, Shared);
      Languages        : constant Variable_Value :=
                           Util.Value_Of
                             (Name_Languages,
                              Project.Decl.Attributes, Shared);

   begin
      if Project.Source_Dirs /= Nil_String then
         if Source_Dirs.Values = Nil_String
           and then Source_Files.Values = Nil_String
           and then Languages.Values = Nil_String
           and then Source_List_File.Default
         then
            Project.Source_Dirs := Nil_String;

         else
            Error_Msg
              (Data.Flags,
               "non-empty set of sources can''t be defined in an abstract"
               & " project",
               Project.Location, Project);
         end if;
      end if;
   end Check_Abstract_Project;

   -------------------------
   -- Check_Configuration --
   -------------------------

   procedure Check_Configuration
     (Project : Project_Id;
      Data    : in out Tree_Processing_Data)
   is
      Shared          : constant Shared_Project_Tree_Data_Access :=
                          Data.Tree.Shared;

      Dot_Replacement : File_Name_Type := No_File;
      Casing          : Casing_Type    := All_Lower_Case;
      Separate_Suffix : File_Name_Type := No_File;

      Lang_Index : Language_Ptr := No_Language_Index;
      --  The index of the language data being checked

      procedure Process_Project_Level_Simple_Attributes;
      --  Process the simple attributes at the project level

      procedure Process_Project_Level_Array_Attributes;
      --  Process the associate array attributes at the project level

      procedure Process_Packages;
      --  Read the packages of the project

      ----------------------
      -- Process_Packages --
      ----------------------

      procedure Process_Packages is
         Packages : Package_Id;
         Element  : Package_Element;

         procedure Process_Binder (Arrays : Array_Id);
         --  Process the associated array attributes of package Binder

         procedure Process_Builder (Attributes : Variable_Id);
         --  Process the simple attributes of package Builder

         procedure Process_Clean (Attributes : Variable_Id);
         --  Process the simple attributes of package Clean

         procedure Process_Clean  (Arrays : Array_Id);
         --  Process the associated array attributes of package Clean

         procedure Process_Compiler (Attributes : Variable_Id);
         --  Process the simple attributes of package Compiler

         procedure Process_Compiler (Arrays : Array_Id);
         --  Process the associated array attributes of package Compiler

         procedure Process_Naming (Attributes : Variable_Id);
         --  Process the simple attributes of package Naming

         procedure Process_Naming (Arrays : Array_Id);
         --  Process the associated array attributes of package Naming

         procedure Process_Linker (Attributes : Variable_Id);
         --  Process the simple attributes of package Linker of a
         --  configuration project.

         procedure Process_Linker (Arrays : Array_Id);
         --  Process the associated array attributes of package Linker

         procedure Resp_File_Format
           (Name    : Name_Id;
            Format  : out Response_File_Format;
            Success : out Boolean);
         --  Get a response file format named Name. Success is True if Name is
         --  a valine response file format name.

         --------------------
         -- Process_Binder --
         --------------------

         procedure Process_Binder (Arrays : Array_Id) is
            Current_Array_Id : Array_Id;
            Current_Array    : Array_Data;
            Element_Id       : Array_Element_Id;
            Element          : Array_Element;

         begin
            --  Process the associative array attribute of package Binder

            Current_Array_Id := Arrays;
            while Current_Array_Id /= No_Array loop
               Current_Array := Shared.Arrays.Table (Current_Array_Id);

               Element_Id := Current_Array.Value;
               while Element_Id /= No_Array_Element loop
                  Element := Shared.Array_Elements.Table (Element_Id);

                  if Element.Index /= All_Other_Names then

                     --  Get the name of the language

                     Lang_Index :=
                       Get_Language_From_Name
                         (Project, Get_Name_String (Element.Index));

                     if Lang_Index /= No_Language_Index then
                        if Current_Array.Name = Name_Driver then

                           --  Attribute Driver (<language>)

                           Lang_Index.Config.Binder_Driver :=
                             File_Name_Type (Element.Value.Value);

                        elsif Current_Array.Name = Name_Required_Switches then
                           Put
                             (Into_List =>
                                Lang_Index.Config.Binder_Required_Switches,
                              From_List => Element.Value.Values,
                              In_Tree   => Data.Tree);

                        elsif Current_Array.Name = Name_Prefix then

                           --  Attribute Prefix (<language>)

                           Lang_Index.Config.Binder_Prefix :=
                             Element.Value.Value;

                        elsif Current_Array.Name = Name_Objects_Path then

                           --  Attribute Objects_Path (<language>)

                           Lang_Index.Config.Objects_Path :=
                             Element.Value.Value;

                        elsif Current_Array.Name = Name_Objects_Path_File then

                           --  Attribute Objects_Path (<language>)

                           Lang_Index.Config.Objects_Path_File :=
                             Element.Value.Value;
                        end if;
                     end if;
                  end if;

                  Element_Id := Element.Next;
               end loop;

               Current_Array_Id := Current_Array.Next;
            end loop;
         end Process_Binder;

         ---------------------
         -- Process_Builder --
         ---------------------

         procedure Process_Builder (Attributes : Variable_Id) is
            Attribute_Id : Variable_Id;
            Attribute    : Variable;

         begin
            --  Process non associated array attribute from package Builder

            Attribute_Id := Attributes;
            while Attribute_Id /= No_Variable loop
               Attribute := Shared.Variable_Elements.Table (Attribute_Id);

               if not Attribute.Value.Default then
                  if Attribute.Name = Name_Executable_Suffix then

                     --  Attribute Executable_Suffix: the suffix of the
                     --  executables.

                     Project.Config.Executable_Suffix :=
                       Attribute.Value.Value;
                  end if;
               end if;

               Attribute_Id := Attribute.Next;
            end loop;
         end Process_Builder;

         -------------------
         -- Process_Clean --
         -------------------

         procedure Process_Clean (Attributes : Variable_Id) is
            Attribute_Id : Variable_Id;
            Attribute    : Variable;
            List         : String_List_Id;

         begin
            --  Process non associated array attributes from package Clean

            Attribute_Id := Attributes;
            while Attribute_Id /= No_Variable loop
               Attribute := Shared.Variable_Elements.Table (Attribute_Id);

               if not Attribute.Value.Default then
                  if Attribute.Name = Name_Artifacts_In_Exec_Dir then

                     --  Attribute Artifacts_In_Exec_Dir: the list of file
                     --  names to be cleaned in the exec dir of the main
                     --  project.

                     List := Attribute.Value.Values;

                     if List /= Nil_String then
                        Put (Into_List =>
                               Project.Config.Artifacts_In_Exec_Dir,
                             From_List => List,
                             In_Tree   => Data.Tree);
                     end if;

                  elsif Attribute.Name = Name_Artifacts_In_Object_Dir then

                     --  Attribute Artifacts_In_Exec_Dir: the list of file
                     --  names to be cleaned in the object dir of every
                     --  project.

                     List := Attribute.Value.Values;

                     if List /= Nil_String then
                        Put (Into_List =>
                               Project.Config.Artifacts_In_Object_Dir,
                             From_List => List,
                             In_Tree   => Data.Tree);
                     end if;
                  end if;
               end if;

               Attribute_Id := Attribute.Next;
            end loop;
         end Process_Clean;

         procedure Process_Clean  (Arrays : Array_Id) is
            Current_Array_Id : Array_Id;
            Current_Array    : Array_Data;
            Element_Id       : Array_Element_Id;
            Element          : Array_Element;
            List             : String_List_Id;

         begin
            --  Process the associated array attributes of package Clean

            Current_Array_Id := Arrays;
            while Current_Array_Id /= No_Array loop
               Current_Array := Shared.Arrays.Table (Current_Array_Id);

               Element_Id := Current_Array.Value;
               while Element_Id /= No_Array_Element loop
                  Element := Shared.Array_Elements.Table (Element_Id);

                  --  Get the name of the language

                  Lang_Index :=
                    Get_Language_From_Name
                      (Project, Get_Name_String (Element.Index));

                  if Lang_Index /= No_Language_Index then
                     --  Attribute Object_Artifact_Extensions (<language>)

                     if Current_Array.Name =
                          Name_Object_Artifact_Extensions
                     then
                        List := Element.Value.Values;

                        if List /= Nil_String then
                           Put (Into_List =>
                                  Lang_Index.Config.Clean_Object_Artifacts,
                                From_List => List,
                                In_Tree   => Data.Tree);
                        end if;

                        --  Attribute Source_Artifact_Extensions (<language>)

                     elsif Current_Array.Name =
                             Name_Source_Artifact_Extensions
                     then
                        List := Element.Value.Values;

                        if List /= Nil_String then
                           Put (Into_List =>
                                  Lang_Index.Config.Clean_Source_Artifacts,
                                From_List => List,
                                In_Tree   => Data.Tree);
                        end if;

                     end if;
                  end if;

                  Element_Id := Element.Next;
               end loop;

               Current_Array_Id := Current_Array.Next;
            end loop;
         end Process_Clean;

         ----------------------
         -- Process_Compiler --
         ----------------------

         procedure Process_Compiler (Attributes : Variable_Id) is
            Attribute_Id : Variable_Id;
            Attribute    : Variable;

         begin
            --  Process non associated array attributes from package Compiler

            Attribute_Id := Attributes;
            while Attribute_Id /= No_Variable loop
               Attribute := Shared.Variable_Elements.Table (Attribute_Id);

               if not Attribute.Value.Default then
                  if Attribute.Name = Name_Max_Command_Line_Length then
                     declare
                        Value : Natural;

                     begin
                        Value :=
                          Natural'Value (Get_Name_String
                                         (Attribute.Value.Value));

                        if Project.Config.Max_Command_Line_Length = 0 or else
                          Value < Project.Config.Max_Command_Line_Length
                        then
                           Project.Config.Max_Command_Line_Length := Value;
                        end if;

                     exception
                        when Constraint_Error =>
                           Error_Msg
                             (Data.Flags,
                              "value must be positive or equal to 0",
                              Attribute.Value.Location, Project);
                     end;
                  end if;
               end if;

               Attribute_Id := Attribute.Next;
            end loop;
         end Process_Compiler;

         procedure Process_Compiler (Arrays : Array_Id) is
            Current_Array_Id : Array_Id;
            Current_Array    : Array_Data;
            Element_Id       : Array_Element_Id;
            Element          : Array_Element;
            List             : String_List_Id;

         begin
            --  Process the associative array attribute of package Compiler

            Current_Array_Id := Arrays;
            while Current_Array_Id /= No_Array loop
               Current_Array := Shared.Arrays.Table (Current_Array_Id);

               Element_Id := Current_Array.Value;
               while Element_Id /= No_Array_Element loop
                  Element := Shared.Array_Elements.Table (Element_Id);

                  if Element.Index /= All_Other_Names then

                     --  Get the name of the language

                     Lang_Index := Get_Language_From_Name
                       (Project, Get_Name_String (Element.Index));

                     if Lang_Index /= No_Language_Index then
                        --  Attribute Dependency_Kind (<language>)

                        if Current_Array.Name = Name_Dependency_Kind then
                           Get_Name_String (Element.Value.Value);

                           begin
                              Lang_Index.Config.Dependency_Kind :=
                                Dependency_File_Kind'Value
                                  (Name_Buffer (1 .. Name_Len));

                           exception
                              when Constraint_Error =>
                                 Error_Msg
                                   (Data.Flags,
                                    "illegal value for Dependency_Kind",
                                    Element.Value.Location,
                                    Project);
                           end;

                           --  Attribute Dependency_Switches (<language>)

                        elsif
                          Current_Array.Name = Name_Dependency_Switches
                        then
                           if Lang_Index.Config.Dependency_Kind = None then
                              Lang_Index.Config.Dependency_Kind := Makefile;
                           end if;

                           List := Element.Value.Values;

                           if List /= Nil_String then
                              Put (Into_List =>
                                     Lang_Index.Config.Dependency_Option,
                                   From_List => List,
                                   In_Tree   => Data.Tree);
                           end if;

                           --  Attribute Dependency_Driver (<language>)

                        elsif Current_Array.Name = Name_Dependency_Driver then
                           if Lang_Index.Config.Dependency_Kind = None then
                              Lang_Index.Config.Dependency_Kind := Makefile;
                           end if;

                           List := Element.Value.Values;

                           if List /= Nil_String then
                              Put (Into_List =>
                                     Lang_Index.Config.Compute_Dependency,
                                   From_List => List,
                                   In_Tree   => Data.Tree);
                           end if;

                           --  Attribute Language_Kind (<language>)

                        elsif Current_Array.Name = Name_Language_Kind then
                           Get_Name_String (Element.Value.Value);

                           begin
                              Lang_Index.Config.Kind :=
                                Language_Kind'Value
                                  (Name_Buffer (1 .. Name_Len));

                           exception
                              when Constraint_Error =>
                                 Error_Msg
                                   (Data.Flags,
                                    "illegal value for Language_Kind",
                                    Element.Value.Location,
                                    Project);
                           end;

                           --  Attribute Include_Switches (<language>)

                        elsif Current_Array.Name = Name_Include_Switches then
                           List := Element.Value.Values;

                           if List = Nil_String then
                              Error_Msg
                                (Data.Flags, "include option cannot be null",
                                 Element.Value.Location, Project);
                           end if;

                           Put (Into_List => Lang_Index.Config.Include_Option,
                                From_List => List,
                                In_Tree   => Data.Tree);

                           --  Attribute Include_Switches_Via_Spec
                           --             (<language>)

                        elsif Current_Array.Name =
                          Name_Include_Switches_Via_Spec
                        then
                           List := Element.Value.Values;

                           if List = Nil_String then
                              Error_Msg
                                (Data.Flags,
                                 "include switches via spec cannot be null",
                                 Element.Value.Location, Project);
                           end if;

                           Put (Into_List =>
                                  Lang_Index.Config.Include_Switches_Via_Spec,
                                From_List => List,
                                In_Tree   => Data.Tree);

                           --  Attribute Include_Path (<language>)

                        elsif Current_Array.Name = Name_Include_Path then
                           Lang_Index.Config.Include_Path :=
                             Element.Value.Value;

                           --  Attribute Include_Path_File (<language>)

                        elsif Current_Array.Name = Name_Include_Path_File then
                           Lang_Index.Config.Include_Path_File :=
                             Element.Value.Value;

                           --  Attribute Driver (<language>)

                        elsif Current_Array.Name = Name_Driver then
                           Lang_Index.Config.Compiler_Driver :=
                             File_Name_Type (Element.Value.Value);

                           --  Attributes Required_Switches (<language>) and
                           --  Leading_Required_Switches (<language>.

                        elsif Current_Array.Name = Name_Required_Switches
                          or else
                            Current_Array.Name = Name_Leading_Required_Switches
                        then
                           Put (Into_List =>
                                  Lang_Index.Config.
                                    Compiler_Leading_Required_Switches,
                                From_List => Element.Value.Values,
                                In_Tree   => Data.Tree);

                           --  Attribute Trailing_Required_Switches (<language>

                        elsif
                          Current_Array.Name = Name_Trailing_Required_Switches
                        then
                           Put (Into_List =>
                                  Lang_Index.Config.
                                    Compiler_Trailing_Required_Switches,
                                From_List => Element.Value.Values,
                                In_Tree   => Data.Tree);

                           --  Attribute Multi_Unit_Switches (<language>)

                        elsif
                          Current_Array.Name = Name_Multi_Unit_Switches
                        then
                           Put (Into_List =>
                                  Lang_Index.Config.Multi_Unit_Switches,
                                From_List => Element.Value.Values,
                                In_Tree   => Data.Tree);

                           --  Attribute Multi_Unit_Object_Separator (lang)

                        elsif
                          Current_Array.Name = Name_Multi_Unit_Object_Separator
                        then
                           Get_Name_String (Element.Value.Value);

                           if Name_Len /= 1 then
                              Error_Msg
                                (Data.Flags,
                                 "multi-unit object separator must have a"
                                 & " single character",
                                 Element.Value.Location, Project);

                           elsif Name_Buffer (1) = ' ' then
                              Error_Msg
                                (Data.Flags,
                                 "multi-unit object separator cannot be a"
                                 & " space",
                                 Element.Value.Location, Project);

                           else
                              Lang_Index.Config.Multi_Unit_Object_Separator :=
                                Name_Buffer (1);
                           end if;

                           --  Attribute Source_File_Switches (<language>)

                        elsif
                          Current_Array.Name = Name_Source_File_Switches
                        then
                           Put (Into_List =>
                                  Lang_Index.Config.Source_File_Switches,
                                From_List => Element.Value.Values,
                                In_Tree   => Data.Tree);

                           --  Attribute Object_File_Suffix (<language>)

                        elsif Current_Array.Name = Name_Object_File_Suffix then
                           if Get_Name_String (Element.Value.Value) = "" then
                              Error_Msg
                                (Data.Flags,
                                 "object file suffix cannot be empty",
                                 Element.Value.Location, Project);

                           else
                              Lang_Index.Config.Object_File_Suffix :=
                                Element.Value.Value;
                           end if;

                           --  Attribute Object_File_Switches (<language>)

                        elsif
                          Current_Array.Name = Name_Object_File_Switches
                        then
                           Put (Into_List =>
                                  Lang_Index.Config.Object_File_Switches,
                                From_List => Element.Value.Values,
                                In_Tree   => Data.Tree);

                           --  Attribute Object_Path_Switches (<language>)

                        elsif
                          Current_Array.Name = Name_Object_Path_Switches
                        then
                           Put (Into_List =>
                                  Lang_Index.Config.Object_Path_Switches,
                                From_List => Element.Value.Values,
                                In_Tree   => Data.Tree);

                           --  Attribute Compiler_Pic_Option (<language>)

                        elsif Current_Array.Name = Name_Pic_Option then
                           List := Element.Value.Values;

                           if List = Nil_String then
                              Error_Msg
                                (Data.Flags,
                                 "compiler PIC option cannot be null",
                                 Element.Value.Location, Project);
                           end if;

                           Put (Into_List =>
                                  Lang_Index.Config.Compilation_PIC_Option,
                                From_List => List,
                                In_Tree   => Data.Tree);

                           --  Attribute Mapping_File_Switches (<language>)

                        elsif
                          Current_Array.Name = Name_Mapping_File_Switches
                        then
                           List := Element.Value.Values;

                           if List = Nil_String then
                              Error_Msg
                                (Data.Flags,
                                 "mapping file switches cannot be null",
                                 Element.Value.Location, Project);
                           end if;

                           Put (Into_List =>
                                  Lang_Index.Config.Mapping_File_Switches,
                                From_List => List,
                                In_Tree   => Data.Tree);

                           --  Attribute Mapping_Spec_Suffix (<language>)

                        elsif
                          Current_Array.Name = Name_Mapping_Spec_Suffix
                        then
                           Lang_Index.Config.Mapping_Spec_Suffix :=
                             File_Name_Type (Element.Value.Value);

                           --  Attribute Mapping_Body_Suffix (<language>)

                        elsif
                          Current_Array.Name = Name_Mapping_Body_Suffix
                        then
                           Lang_Index.Config.Mapping_Body_Suffix :=
                             File_Name_Type (Element.Value.Value);

                           --  Attribute Config_File_Switches (<language>)

                        elsif
                          Current_Array.Name = Name_Config_File_Switches
                        then
                           List := Element.Value.Values;

                           if List = Nil_String then
                              Error_Msg
                                (Data.Flags,
                                 "config file switches cannot be null",
                                 Element.Value.Location, Project);
                           end if;

                           Put (Into_List =>
                                  Lang_Index.Config.Config_File_Switches,
                                From_List => List,
                                In_Tree   => Data.Tree);

                           --  Attribute Objects_Path (<language>)

                        elsif Current_Array.Name = Name_Objects_Path then
                           Lang_Index.Config.Objects_Path :=
                             Element.Value.Value;

                           --  Attribute Objects_Path_File (<language>)

                        elsif Current_Array.Name = Name_Objects_Path_File then
                           Lang_Index.Config.Objects_Path_File :=
                             Element.Value.Value;

                           --  Attribute Config_Body_File_Name (<language>)

                        elsif
                          Current_Array.Name = Name_Config_Body_File_Name
                        then
                           Lang_Index.Config.Config_Body :=
                             Element.Value.Value;

                           --  Attribute Config_Body_File_Name_Index (<lang>)

                        elsif
                          Current_Array.Name = Name_Config_Body_File_Name_Index
                        then
                           Lang_Index.Config.Config_Body_Index :=
                             Element.Value.Value;

                           --  Attribute Config_Body_File_Name_Pattern(<lang>)

                        elsif
                          Current_Array.Name =
                            Name_Config_Body_File_Name_Pattern
                        then
                           Lang_Index.Config.Config_Body_Pattern :=
                             Element.Value.Value;

                           --  Attribute Config_Spec_File_Name (<language>)

                        elsif
                          Current_Array.Name = Name_Config_Spec_File_Name
                        then
                           Lang_Index.Config.Config_Spec :=
                             Element.Value.Value;

                           --  Attribute Config_Spec_File_Name_Index (<lang>)

                        elsif
                          Current_Array.Name = Name_Config_Spec_File_Name_Index
                        then
                           Lang_Index.Config.Config_Spec_Index :=
                             Element.Value.Value;

                           --  Attribute Config_Spec_File_Name_Pattern(<lang>)

                        elsif
                          Current_Array.Name =
                            Name_Config_Spec_File_Name_Pattern
                        then
                           Lang_Index.Config.Config_Spec_Pattern :=
                             Element.Value.Value;

                        --  Attribute Config_File_Dependency_Support (<lang>)

                        elsif
                          Current_Array.Name =
                            Name_Config_File_Dependency_Support
                        then
                           begin
                              Lang_Index.Config.Config_File_Dependency_Support
                                := Boolean'Value
                                     (Get_Name_String (Element.Value.Value));
                           exception
                              when Constraint_Error =>
                                 Error_Msg
                                   (Data.Flags,
                                    "illegal value for "
                                    & "Config_File_Dependency_Support",
                                    Element.Value.Location, Project);
                           end;

                        --  Attribute Config_File_Unique (<language>)

                        elsif Current_Array.Name = Name_Config_File_Unique then
                           begin
                              Lang_Index.Config.Config_File_Unique :=
                                Boolean'Value
                                  (Get_Name_String (Element.Value.Value));
                           exception
                              when Constraint_Error =>
                                 Error_Msg
                                   (Data.Flags,
                                    "illegal value for Config_File_Unique",
                                    Element.Value.Location, Project);
                           end;

                           --  Attribute Response_File_Format (<language>)

                        elsif
                          Current_Array.Name = Name_Response_File_Format
                        then
                           declare
                              Success : Boolean;
                           begin
                              Resp_File_Format
                                (Element.Value.Value,
                                 Lang_Index.Config.Resp_File_Format,
                                 Success);

                              if not Success then
                                 Error_Msg
                                   (Data.Flags,
                                    "illegal response file format",
                                    Element.Value.Location, Project);
                              end if;
                           end;

                           --  Attribute Response_File_Switches (<language>)

                        elsif
                          Current_Array.Name = Name_Response_File_Switches
                        then
                           Put
                             (Into_List => Lang_Index.Config.Resp_File_Options,
                              From_List => Element.Value.Values,
                              In_Tree   => Data.Tree);
                        end if;
                     end if;
                  end if;

                  Element_Id := Element.Next;
               end loop;

               Current_Array_Id := Current_Array.Next;
            end loop;
         end Process_Compiler;

         --------------------
         -- Process_Naming --
         --------------------

         procedure Process_Naming (Attributes : Variable_Id) is
            Attribute_Id : Variable_Id;
            Attribute    : Variable;

         begin
            --  Process non associated array attribute from package Naming

            Attribute_Id := Attributes;
            while Attribute_Id /= No_Variable loop
               Attribute := Shared.Variable_Elements.Table (Attribute_Id);

               if not Attribute.Value.Default then
                  if Attribute.Name = Name_Separate_Suffix then

                     --  Attribute Separate_Suffix

                     Get_Name_String (Attribute.Value.Value);
                     Canonical_Case_File_Name (Name_Buffer (1 .. Name_Len));
                     Separate_Suffix := Name_Find;

                  elsif Attribute.Name = Name_Casing then

                     --  Attribute Casing

                     begin
                        if Attribute.Value.Value /= No_Name then
                           Casing :=
                             Value (Get_Name_String (Attribute.Value.Value));
                        end if;

                     exception
                        when Constraint_Error =>
                           Error_Msg
                             (Data.Flags,
                              "invalid value for Casing",
                              Attribute.Value.Location, Project);
                     end;

                  elsif Attribute.Name = Name_Dot_Replacement then

                     --  Attribute Dot_Replacement

                     Dot_Replacement := File_Name_Type (Attribute.Value.Value);

                  end if;
               end if;

               Attribute_Id := Attribute.Next;
            end loop;
         end Process_Naming;

         procedure Process_Naming (Arrays : Array_Id) is
            Current_Array_Id : Array_Id;
            Current_Array    : Array_Data;
            Element_Id       : Array_Element_Id;
            Element          : Array_Element;

         begin
            --  Process the associative array attribute of package Naming

            Current_Array_Id := Arrays;
            while Current_Array_Id /= No_Array loop
               Current_Array := Shared.Arrays.Table (Current_Array_Id);

               Element_Id := Current_Array.Value;
               while Element_Id /= No_Array_Element loop
                  Element := Shared.Array_Elements.Table (Element_Id);

                  --  Get the name of the language

                  Lang_Index := Get_Language_From_Name
                    (Project, Get_Name_String (Element.Index));

                  if Lang_Index /= No_Language_Index
                    and then Element.Value.Kind = Single
                    and then Element.Value.Value /= No_Name
                  then
                     if Current_Array.Name = Name_Spec_Suffix
                       or else Current_Array.Name = Name_Specification_Suffix
                     then

                        --  Attribute Spec_Suffix (<language>)

                        Get_Name_String (Element.Value.Value);
                        Canonical_Case_File_Name
                          (Name_Buffer (1 .. Name_Len));
                        Lang_Index.Config.Naming_Data.Spec_Suffix :=
                          Name_Find;

                     elsif Current_Array.Name = Name_Implementation_Suffix
                       or else Current_Array.Name = Name_Body_Suffix
                     then

                        Get_Name_String (Element.Value.Value);
                        Canonical_Case_File_Name
                          (Name_Buffer (1 .. Name_Len));

                        --  Attribute Body_Suffix (<language>)

                        Lang_Index.Config.Naming_Data.Body_Suffix :=
                          Name_Find;
                        Lang_Index.Config.Naming_Data.Separate_Suffix :=
                          Lang_Index.Config.Naming_Data.Body_Suffix;
                     end if;
                  end if;

                  Element_Id := Element.Next;
               end loop;

               Current_Array_Id := Current_Array.Next;
            end loop;
         end Process_Naming;

         --------------------
         -- Process_Linker --
         --------------------

         procedure Process_Linker (Attributes : Variable_Id) is
            Attribute_Id : Variable_Id;
            Attribute    : Variable;

         begin
            --  Process non associated array attribute from package Linker

            Attribute_Id := Attributes;
            while Attribute_Id /= No_Variable loop
               Attribute := Shared.Variable_Elements.Table (Attribute_Id);

               if not Attribute.Value.Default then
                  if Attribute.Name = Name_Driver then

                     --  Attribute Linker'Driver: the default linker to use

                     Project.Config.Linker :=
                       Path_Name_Type (Attribute.Value.Value);

                     --  Linker'Driver is also used to link shared libraries
                     --  if the obsolescent attribute Library_GCC has not been
                     --  specified.

                     if Project.Config.Shared_Lib_Driver = No_File then
                        Project.Config.Shared_Lib_Driver :=
                          File_Name_Type (Attribute.Value.Value);
                     end if;

                  elsif Attribute.Name = Name_Required_Switches then

                     --  Attribute Required_Switches: the minimum trailing
                     --  options to use when invoking the linker

                     Put (Into_List =>
                            Project.Config.Trailing_Linker_Required_Switches,
                          From_List => Attribute.Value.Values,
                          In_Tree   => Data.Tree);

                  elsif Attribute.Name = Name_Map_File_Option then
                     Project.Config.Map_File_Option := Attribute.Value.Value;

                  elsif Attribute.Name = Name_Max_Command_Line_Length then
                     declare
                        Value : Natural;

                     begin
                        Value :=
                          Natural'Value (Get_Name_String
                                         (Attribute.Value.Value));

                        if Project.Config.Max_Command_Line_Length = 0 or else
                          Value < Project.Config.Max_Command_Line_Length
                        then
                           Project.Config.Max_Command_Line_Length := Value;
                        end if;

                     exception
                        when Constraint_Error =>
                           Error_Msg
                             (Data.Flags,
                              "value must be positive or equal to 0",
                              Attribute.Value.Location, Project);
                     end;

                  elsif Attribute.Name = Name_Response_File_Format then
                     declare
                        Success : Boolean;
                     begin
                        Resp_File_Format
                          (Name    => Attribute.Value.Value,
                           Format  => Project.Config.Resp_File_Format,
                           Success => Success);

                        if not Success then
                           Error_Msg
                             (Data.Flags,
                              "illegal response file format",
                              Attribute.Value.Location, Project);
                        end if;
                     end;

                  elsif Attribute.Name = Name_Response_File_Switches then
                     Put (Into_List => Project.Config.Resp_File_Options,
                          From_List => Attribute.Value.Values,
                          In_Tree   => Data.Tree);

                  elsif Attribute.Name = Name_Export_File_Switch then

                     Project.Config.Export_File_Switch :=
                       Attribute.Value.Value;

                  elsif Attribute.Name = Name_Export_File_Format then

                     declare
                        Name : constant Name_Id :=
                                 Get_Lower_Name_Id
                                   (Get_Name_String (Attribute.Value.Value));
                     begin
                        if Name = Name_None then
                           Project.Config.Export_File_Format := None;

                        elsif Name = Name_Gnu then
                           Project.Config.Export_File_Format := GNU;

                        elsif Name = Name_Def then
                           Project.Config.Export_File_Format := Def;

                        elsif Name = Name_Flat then
                           Project.Config.Export_File_Format := Flat;

                        else
                           Error_Msg
                             (Data.Flags,
                              "illegal export file format",
                              Attribute.Value.Location, Project);
                        end if;
                     end;
                  end if;
               end if;

               Attribute_Id := Attribute.Next;
            end loop;
         end Process_Linker;

         procedure Process_Linker (Arrays : Array_Id) is
            Current_Array_Id : Array_Id;
            Current_Array    : Array_Data;
            Element_Id       : Array_Element_Id;
            Element          : Array_Element;

         begin
            --  Process the associated array attributes of package Clean

            Current_Array_Id := Arrays;

            while Current_Array_Id /= No_Array loop
               Current_Array := Shared.Arrays.Table (Current_Array_Id);

               if Current_Array.Name = Name_Unconditional_Linking then
                  Element_Id := Current_Array.Value;

                  while Element_Id /= No_Array_Element loop
                     Element := Shared.Array_Elements.Table (Element_Id);

                     --  Get the name of the language

                     Lang_Index :=
                       Get_Language_From_Name
                         (Project, Get_Name_String (Element.Index));

                     if Lang_Index /= No_Language_Index then
                        --  Attribute Unconditional_Linking (<language>)

                        begin
                           Lang_Index.Unconditional_Linking :=
                             Boolean'Value
                               (Get_Name_String (Element.Value.Value));
                        exception
                           when Constraint_Error =>
                              Error_Msg
                                (Data.Flags,
                                 "illegal value for Unconditional_Linking",
                                 Element.Value.Location,
                                 Project);
                        end;
                     end if;

                     Element_Id := Element.Next;
                  end loop;
               end if;

               Current_Array_Id := Current_Array.Next;
            end loop;
         end Process_Linker;

         ----------------------
         -- Resp_File_Format --
         ----------------------

         procedure Resp_File_Format
           (Name    : Name_Id;
            Format  : out Response_File_Format;
            Success : out Boolean)
         is
            Low_Name : constant Name_Id :=
                         Get_Lower_Name_Id (Get_Name_String (Name));
         begin
            Success := True;

            if Low_Name = Name_None then
               Format := None;

            elsif Low_Name = Name_Gnu then
               Format := GNU;

            elsif Low_Name = Name_Object_List then
               Format := Object_List;

            elsif Low_Name = Name_Option_List then
               Format := Option_List;

            elsif Low_Name = Name_Gcc then
               Format := GCC;

            elsif Low_Name = Name_Gcc_Gnu then
               Format := GCC_GNU;

            elsif Low_Name = Name_Gcc_Option_List then
               Format := GCC_Option_List;

            elsif Low_Name = Name_Gcc_Object_List then
               Format := GCC_Object_List;

            else
               Success := False;
               Format  := None;
            end if;
         end Resp_File_Format;

      --  Start of processing for Process_Packages

      begin
         Packages := Project.Decl.Packages;
         while Packages /= No_Package loop
            Element := Shared.Packages.Table (Packages);

            if Element.Name = Name_Binder then

               --  Process attributes of package Binder

               Process_Binder (Element.Decl.Arrays);

            elsif Element.Name = Name_Builder then

               --  Process attributes of package Builder

               Process_Builder (Element.Decl.Attributes);

            elsif Element.Name = Name_Clean then

               --  Process attributes of package Clean

               Process_Clean (Element.Decl.Attributes);
               Process_Clean (Element.Decl.Arrays);

            elsif Element.Name = Name_Compiler then

               --  Process attributes of package Compiler

               Process_Compiler (Element.Decl.Attributes);
               Process_Compiler (Element.Decl.Arrays);

            elsif Element.Name = Name_Linker then

               --  Process attributes of package Linker

               Process_Linker (Element.Decl.Attributes);
               Process_Linker (Element.Decl.Arrays);

            elsif Element.Name = Name_Naming then

               --  Process attributes of package Naming

               Process_Naming (Element.Decl.Attributes);
               Process_Naming (Element.Decl.Arrays);

            end if;

            Packages := Element.Next;
         end loop;
      end Process_Packages;

      ---------------------------------------------
      -- Process_Project_Level_Simple_Attributes --
      ---------------------------------------------

      procedure Process_Project_Level_Simple_Attributes is
         Attribute_Id : Variable_Id;
         Attribute    : Variable;
         List         : String_List_Id;

      begin
         --  Process non associated array attribute at project level

         Attribute_Id := Project.Decl.Attributes;
         while Attribute_Id /= No_Variable loop
            Attribute := Shared.Variable_Elements.Table (Attribute_Id);

            if not Attribute.Value.Default then
               if Attribute.Name = Name_Target then

                  --  Attribute Target: the target specified

                  Project.Config.Target := Attribute.Value.Value;

               elsif Attribute.Name = Name_Library_Builder then

                  --  Attribute Library_Builder: the application to invoke
                  --  to build libraries.

                  Project.Config.Library_Builder :=
                    Path_Name_Type (Attribute.Value.Value);

               elsif Attribute.Name = Name_Archive_Builder then

                  --  Attribute Archive_Builder: the archive builder
                  --  (usually "ar") and its minimum options (usually "cr").

                  List := Attribute.Value.Values;

                  if List = Nil_String then
                     Error_Msg
                       (Data.Flags,
                        "archive builder cannot be null",
                        Attribute.Value.Location, Project);
                  end if;

                  Put (Into_List => Project.Config.Archive_Builder,
                       From_List => List,
                       In_Tree   => Data.Tree);

               elsif Attribute.Name = Name_Archive_Builder_Append_Option then

                  --  Attribute Archive_Builder: the archive builder
                  --  (usually "ar") and its minimum options (usually "cr").

                  List := Attribute.Value.Values;

                  if List /= Nil_String then
                     Put
                       (Into_List =>
                          Project.Config.Archive_Builder_Append_Option,
                        From_List => List,
                        In_Tree   => Data.Tree);
                  end if;

               elsif Attribute.Name = Name_Archive_Indexer then

                  --  Attribute Archive_Indexer: the optional archive
                  --  indexer (usually "ranlib") with its minimum options
                  --  (usually none).

                  List := Attribute.Value.Values;

                  if List = Nil_String then
                     Error_Msg
                       (Data.Flags,
                        "archive indexer cannot be null",
                        Attribute.Value.Location, Project);
                  end if;

                  Put (Into_List => Project.Config.Archive_Indexer,
                       From_List => List,
                       In_Tree   => Data.Tree);

               elsif Attribute.Name = Name_Object_Lister then

                  --  Attribute Object_Lister: the optional object
                  --  lister (usually "nm") with its minimum options.

                  List := Attribute.Value.Values;

                  if List = Nil_String then
                     Error_Msg
                       (Data.Flags,
                        "object lister cannot be null",
                        Attribute.Value.Location, Project);
                  end if;

                  Put (Into_List => Project.Config.Object_Lister,
                       From_List => List,
                       In_Tree   => Data.Tree);

               elsif Attribute.Name = Name_Object_Lister_Matcher then

                  --  Attribute Object_Lister_Matcher: mandatory when
                  --  object lister (usually "nm") is defined.

                  Project.Config.Object_Lister_Matcher :=
                    Attribute.Value.Value;

               elsif Attribute.Name = Name_Library_Partial_Linker then
                  --  Attribute Library_Partial_Linker: the optional linker
                  --  driver with its minimum options, to partially link
                  --  archives.

                  Put (Into_List => Project.Config.Lib_Partial_Linker,
                       From_List => Attribute.Value.Values,
                       In_Tree   => Data.Tree);

               elsif Attribute.Name = Name_Library_GCC then
                  Project.Config.Shared_Lib_Driver :=
                    File_Name_Type (Attribute.Value.Value);
                  Error_Msg
                    (Data.Flags,
                     "?Library_'G'C'C is an obsolescent attribute, use"
                     & " Linker''Driver instead",
                     Attribute.Value.Location, Project);

               elsif Attribute.Name = Name_Archive_Suffix then
                  Project.Config.Archive_Suffix :=
                    File_Name_Type (Attribute.Value.Value);

               elsif Attribute.Name = Name_Linker_Executable_Option then

                  --  Attribute Linker_Executable_Option: optional options
                  --  to specify an executable name. Defaults to "-o".

                  List := Attribute.Value.Values;

                  if List = Nil_String then
                     Error_Msg
                       (Data.Flags,
                        "linker executable option cannot be null",
                        Attribute.Value.Location, Project);
                  end if;

                  Put (Into_List => Project.Config.Linker_Executable_Option,
                       From_List => List,
                       In_Tree   => Data.Tree);

               elsif Attribute.Name = Name_Linker_Lib_Dir_Option then

                  --  Attribute Linker_Lib_Dir_Option: optional options
                  --  to specify a library search directory. Defaults to
                  --  "-L".

                  Get_Name_String (Attribute.Value.Value);

                  if Name_Len = 0 then
                     Error_Msg
                       (Data.Flags,
                        "linker library directory option cannot be empty",
                        Attribute.Value.Location, Project);
                  end if;

                  Project.Config.Linker_Lib_Dir_Option :=
                    Attribute.Value.Value;

               elsif Attribute.Name = Name_Linker_Lib_Name_Option then

                  --  Attribute Linker_Lib_Name_Option: optional options
                  --  to specify the name of a library to be linked in.
                  --  Defaults to "-l".

                  Get_Name_String (Attribute.Value.Value);

                  if Name_Len = 0 then
                     Error_Msg
                       (Data.Flags,
                        "linker library name option cannot be empty",
                        Attribute.Value.Location, Project);
                  end if;

                  Project.Config.Linker_Lib_Name_Option :=
                    Attribute.Value.Value;

               elsif Attribute.Name = Name_Run_Path_Option then

                  --  Attribute Run_Path_Option: optional options to
                  --  specify a path for libraries.

                  List := Attribute.Value.Values;

                  if List /= Nil_String then
                     Put (Into_List => Project.Config.Run_Path_Option,
                          From_List => List,
                          In_Tree   => Data.Tree);
                  end if;

               elsif Attribute.Name = Name_Run_Path_Origin then
                  Get_Name_String (Attribute.Value.Value);

                  if Name_Len = 0 then
                     Error_Msg
                       (Data.Flags,
                        "run path origin cannot be empty",
                        Attribute.Value.Location, Project);
                  end if;

                  Project.Config.Run_Path_Origin := Attribute.Value.Value;

               elsif Attribute.Name = Name_Library_Install_Name_Option then
                  Project.Config.Library_Install_Name_Option :=
                    Attribute.Value.Value;

               elsif Attribute.Name = Name_Separate_Run_Path_Options then
                  declare
                     pragma Unsuppress (All_Checks);
                  begin
                     Project.Config.Separate_Run_Path_Options :=
                       Boolean'Value (Get_Name_String (Attribute.Value.Value));
                  exception
                     when Constraint_Error =>
                        Error_Msg
                          (Data.Flags,
                           "invalid value """
                           & Get_Name_String (Attribute.Value.Value)
                           & """ for Separate_Run_Path_Options",
                           Attribute.Value.Location, Project);
                  end;

               elsif Attribute.Name = Name_Library_Support then
                  declare
                     pragma Unsuppress (All_Checks);
                  begin
                     Project.Config.Lib_Support :=
                       Library_Support'Value (Get_Name_String
                                              (Attribute.Value.Value));
                  exception
                     when Constraint_Error =>
                        Error_Msg
                          (Data.Flags,
                           "invalid value """
                           & Get_Name_String (Attribute.Value.Value)
                           & """ for Library_Support",
                           Attribute.Value.Location, Project);
                  end;

               elsif
                 Attribute.Name = Name_Library_Encapsulated_Supported
               then
                  declare
                     pragma Unsuppress (All_Checks);
                  begin
                     Project.Config.Lib_Encapsulated_Supported :=
                       Boolean'Value (Get_Name_String (Attribute.Value.Value));
                  exception
                     when Constraint_Error =>
                        Error_Msg
                          (Data.Flags,
                           "invalid value """
                           & Get_Name_String (Attribute.Value.Value)
                           & """ for Library_Encapsulated_Supported",
                           Attribute.Value.Location, Project);
                  end;

               elsif Attribute.Name = Name_Shared_Library_Prefix then
                  Project.Config.Shared_Lib_Prefix :=
                    File_Name_Type (Attribute.Value.Value);

               elsif Attribute.Name = Name_Shared_Library_Suffix then
                  Project.Config.Shared_Lib_Suffix :=
                    File_Name_Type (Attribute.Value.Value);

               elsif Attribute.Name = Name_Symbolic_Link_Supported then
                  declare
                     pragma Unsuppress (All_Checks);
                  begin
                     Project.Config.Symbolic_Link_Supported :=
                       Boolean'Value (Get_Name_String
                                      (Attribute.Value.Value));
                  exception
                     when Constraint_Error =>
                        Error_Msg
                          (Data.Flags,
                           "invalid value """
                           & Get_Name_String (Attribute.Value.Value)
                           & """ for Symbolic_Link_Supported",
                           Attribute.Value.Location, Project);
                  end;

               elsif
                 Attribute.Name = Name_Library_Major_Minor_Id_Supported
               then
                  declare
                     pragma Unsuppress (All_Checks);
                  begin
                     Project.Config.Lib_Maj_Min_Id_Supported :=
                       Boolean'Value (Get_Name_String
                                      (Attribute.Value.Value));
                  exception
                     when Constraint_Error =>
                        Error_Msg
                          (Data.Flags,
                           "invalid value """
                           & Get_Name_String (Attribute.Value.Value)
                           & """ for Library_Major_Minor_Id_Supported",
                           Attribute.Value.Location, Project);
                  end;

               elsif Attribute.Name = Name_Library_Auto_Init_Supported then
                  declare
                     pragma Unsuppress (All_Checks);
                  begin
                     Project.Config.Auto_Init_Supported :=
                       Boolean'Value (Get_Name_String (Attribute.Value.Value));
                  exception
                     when Constraint_Error =>
                        Error_Msg
                          (Data.Flags,
                           "invalid value """
                           & Get_Name_String (Attribute.Value.Value)
                           & """ for Library_Auto_Init_Supported",
                           Attribute.Value.Location, Project);
                  end;

               elsif Attribute.Name = Name_Shared_Library_Minimum_Switches then
                  List := Attribute.Value.Values;

                  if List /= Nil_String then
                     Put (Into_List => Project.Config.Shared_Lib_Min_Options,
                          From_List => List,
                          In_Tree   => Data.Tree);
                  end if;

               elsif Attribute.Name = Name_Library_Version_Switches then
                  List := Attribute.Value.Values;

                  if List /= Nil_String then
                     Put (Into_List => Project.Config.Lib_Version_Options,
                          From_List => List,
                          In_Tree   => Data.Tree);
                  end if;

               elsif Attribute.Name = Name_Warning_Message then
                  if Project.Extended_By = No_Project then
                     declare
                        Message : constant Name_Id := Attribute.Value.Value;
                     begin
                        if Message not in No_Name | The_Empty_String then
                           Error_Msg
                             (Data.Flags,
                              "?"
                              & Mask_Control_Characters
                                  (Get_Name_String (Message)),
                              Project.Location,
                              Project);
                        end if;
                     end;
                  end if;
               end if;
            end if;

            Attribute_Id := Attribute.Next;
         end loop;
      end Process_Project_Level_Simple_Attributes;

      --------------------------------------------
      -- Process_Project_Level_Array_Attributes --
      --------------------------------------------

      procedure Process_Project_Level_Array_Attributes is
         Current_Array_Id : Array_Id;
         Current_Array    : Array_Data;
         Element_Id       : Array_Element_Id;
         Element          : Array_Element;
         List             : String_List_Id;

      begin
         --  Process the associative array attributes at project level

         Current_Array_Id := Project.Decl.Arrays;
         while Current_Array_Id /= No_Array loop
            Current_Array := Shared.Arrays.Table (Current_Array_Id);

            Element_Id := Current_Array.Value;
            while Element_Id /= No_Array_Element loop
               Element := Shared.Array_Elements.Table (Element_Id);

               --  Get the name of the language

               Lang_Index :=
                 Get_Language_From_Name
                   (Project, Get_Name_String (Element.Index));

               if Lang_Index /= No_Language_Index then
                  if Current_Array.Name = Name_Inherit_Source_Path then
                     List := Element.Value.Values;

                     if List /= Nil_String then
                        Put
                          (Into_List  =>
                             Lang_Index.Config.Include_Compatible_Languages,
                           From_List  => List,
                           In_Tree    => Data.Tree,
                           Lower_Case => True);
                     end if;

                  elsif Current_Array.Name = Name_Toolchain_Description then

                     --  Attribute Toolchain_Description (<language>)

                     Lang_Index.Config.Toolchain_Description :=
                       Element.Value.Value;

                  elsif Current_Array.Name = Name_Toolchain_Version then

                     --  Attribute Toolchain_Version (<language>)

                     Lang_Index.Config.Toolchain_Version :=
                       Element.Value.Value;

                     --  For Ada, set proper checksum computation mode,
                     --  which has changed from version to version.

                     if Lang_Index.Name = Name_Ada then
                        declare
                           Vers : constant String :=
                             Get_Name_String (Element.Value.Value);
                           pragma Assert (Vers'First = 1);

                        begin
                           --  Version 6.3 or earlier

                           if Vers'Length >= 8
                             and then Vers (1 .. 5) = GNAT_And_Space
                             and then Vers (7) = '.'
                             and then
                               (Vers (6) < '6'
                                or else
                                  (Vers (6) = '6' and then Vers (8) < '4'))
                           then
                              Checksum_GNAT_6_3 := True;

                              --  Version 5.03 or earlier

                              if Vers (6) < '5'
                                or else (Vers (6) = '5'
                                         and then Vers (Vers'Last) < '4')
                              then
                                 Checksum_GNAT_5_03 := True;

                                 --  Version 5.02 or earlier (no checksums)

                                 if Vers (6) /= '5'
                                   or else Vers (Vers'Last) < '3'
                                 then
                                    Checksum_Accumulate_Token_Checksum :=
                                      False;
                                 end if;
                              end if;
                           end if;
                        end;
                     end if;

                  elsif Current_Array.Name = Name_Required_Toolchain_Version
                  then

                     --  Attribute Required_Toolchain_Version (<language>)

                     Lang_Index.Config.Required_Toolchain_Version :=
                       Element.Value.Value;

                  elsif Current_Array.Name = Name_Runtime_Library_Dir then

                     --  Attribute Runtime_Library_Dir (<language>)

                     if Lang_Index.Config.Runtime_Library_Dirs = No_Name_List
                     then
                        Name_List_Table.Append
                          (Shared.Name_Lists,
                           New_Val => (Element.Value.Value, No_Name_List));
                        Lang_Index.Config.Runtime_Library_Dirs :=
                          Name_List_Table.Last (Shared.Name_Lists);
                     end if;

                  elsif Current_Array.Name = Name_Runtime_Library_Dirs then

                     --  Attribute Runtime_Library_Dirs (<language>)

                     declare
                        Dirs    : String_List_Id := Element.Value.Values;
                        Elem    : String_Element;
                     begin
                        Lang_Index.Config.Runtime_Library_Dirs := No_Name_List;
                        Shared.Ada_Runtime_Dir := No_Name;

                        while Dirs /= Nil_String loop
                           Elem := Shared.String_Elements.Table (Dirs);
                           Name_List_Table.Append
                          (Shared.Name_Lists,
                           New_Val =>
                             (Elem.Value,
                              Lang_Index.Config.Runtime_Library_Dirs));
                           Lang_Index.Config.Runtime_Library_Dirs :=
                             Name_List_Table.Last (Shared.Name_Lists);

                           Dirs := Elem.Next;
                        end loop;
                     end;

                  elsif Current_Array.Name = Name_Runtime_Source_Dir then

                     --  Attribute Runtime_Source_Dir (<language>)

                     if Lang_Index.Config.Runtime_Source_Dirs = No_Name_List
                     then
                        Name_List_Table.Append
                          (Shared.Name_Lists,
                           New_Val => (Element.Value.Value, No_Name_List));
                        Lang_Index.Config.Runtime_Source_Dirs :=
                          Name_List_Table.Last (Shared.Name_Lists);
                     end if;

                  elsif Current_Array.Name = Name_Runtime_Source_Dirs then

                     --  Attribute Runtime_Source_Dirs (<language>)

                     declare
                        Dirs    : String_List_Id := Element.Value.Values;
                        Elem    : String_Element;
                     begin
                        Lang_Index.Config.Runtime_Source_Dirs := No_Name_List;

                        while Dirs /= Nil_String loop
                           Elem := Shared.String_Elements.Table (Dirs);
                           Name_List_Table.Append
                          (Shared.Name_Lists,
                           New_Val =>
                             (Elem.Value,
                              Lang_Index.Config.Runtime_Source_Dirs));
                           Lang_Index.Config.Runtime_Source_Dirs :=
                             Name_List_Table.Last (Shared.Name_Lists);

                           Dirs := Elem.Next;
                        end loop;
                     end;

                  elsif Current_Array.Name = Name_Runtime_Dir then
                     declare
                        Runtime_Dir : constant String :=
                          Get_Name_String (Element.Value.Value);

                        procedure Get_Directories
                          (Runtime_Dirs : in out Name_List_Index;
                           Path_File_Name : String;
                           Directory      : String);
                        --  Get the runtime source directories or the runtime
                        --  library directories.

                        ---------------------
                        -- Get_Directories --
                        ---------------------

                        procedure Get_Directories
                          (Runtime_Dirs : in out Name_List_Index;
                           Path_File_Name : String;
                           Directory      : String)
                        is
                           Path : constant String :=
                             Runtime_Dir &
                             Directory_Separator &
                             Path_File_Name;
                           File : Ada.Text_IO.File_Type;
                           Line : String (1 .. 1_000);
                           Last : Natural;
                           Last_Name : Name_List_Index;
                           Local_Runtime_Dirs : Name_List_Index :=
                                                 No_Name_List;
                        begin
                           Runtime_Dirs := No_Name_List;

                           if Is_Regular_File (Path) then
                              Open (File, In_File, Path);
                              while not End_Of_File (File) loop
                                 Get_Line (File, Line, Last);
                                 if Last > 0 then
                                    if Is_Absolute_Path (Line (1 .. Last)) then
                                       Name_Len := 0;
                                    else
                                       Set_Name_Buffer
                                         (Runtime_Dir & Directory_Separator);
                                    end if;

                                    Add_Str_To_Name_Buffer (Line (1 .. Last));

                                    Name_List_Table.Append
                                      (Shared.Name_Lists,
                                       New_Val => (Name_Find, No_Name_List));

                                    Last_Name :=
                                      Name_List_Table.Last (Shared.Name_Lists);

                                    if Local_Runtime_Dirs = No_Name_List then
                                       Runtime_Dirs := Last_Name;

                                    else
                                       Shared.Name_Lists.Table
                                         (Local_Runtime_Dirs).Next :=
                                         Last_Name;
                                    end if;

                                    Local_Runtime_Dirs := Last_Name;
                                 end if;
                              end loop;

                              Close (File);

                           else
                              Name_List_Table.Append
                                (Shared.Name_Lists,
                                 New_Val => (Get_Name_Id
                                               (Runtime_Dir
                                                & Directory_Separator
                                                & Directory),
                                             No_Name_List));
                              Runtime_Dirs :=
                                Name_List_Table.Last (Shared.Name_Lists);
                           end if;
                        end Get_Directories;

                     begin
                        Lang_Index.Config.Runtime_Dir := Element.Value.Value;

                        if Lang_Index.Name = Name_Ada then
                           if Shared.Ada_Runtime_Dir = Element.Value.Value then
                              Lang_Index.Config.Runtime_Library_Dirs :=
                                Shared.Ada_Runtime_Library_Dirs;
                              Lang_Index.Config.Runtime_Source_Dirs :=
                                Shared.Ada_Runtime_Source_Dirs;
                              Lang_Index.Config.Runtime_Library_Version :=
                                Shared.Ada_Runtime_Library_Version;

                           else
                              Get_Directories
                                (Runtime_Dirs   =>
                                   Lang_Index.Config.Runtime_Source_Dirs,
                                 Path_File_Name => "ada_source_path",
                                 Directory      => "adainclude");
                              Get_Directories
                                (Runtime_Dirs   =>
                                   Lang_Index.Config.Runtime_Library_Dirs,
                                 Path_File_Name => "ada_object_path",
                                 Directory      => "adalib");

                              declare
                                 Lib_Dirs : Name_List_Index :=
                                   Lang_Index.Config.Runtime_Library_Dirs;
                                 Library_Dir : Name_Node;
                                 Version : Name_Id := No_Name;

                              begin
                                 while Lib_Dirs /= No_Name_List loop
                                    Library_Dir :=
                                      Shared.Name_Lists.Table
                                        (Lib_Dirs);

                                    if Is_Regular_File
                                      (Get_Name_String
                                         (Library_Dir.Name) & "/system.ali")
                                    then
                                       declare
                                          File : File_Type;
                                          Line : String (1 .. 1_000);
                                          Last : Natural;
                                          Start : Natural;
                                       begin
                                          Open
                                            (File,
                                             In_File,
                                             Get_Name_String
                                               (Library_Dir.Name) &
                                               "/system.ali");
                                          Get_Line (File, Line, Last);
                                          Close (File);
                                          Start :=
                                            Index (Line (1 .. Last), " v");

                                          if Start /= 0 then
                                             Set_Name_Buffer
                                               (GNAT_And_Space);
                                             Add_Str_To_Name_Buffer
                                               (Line (Start + 2 .. Last - 1));
                                             Version := Name_Find;
                                          end if;

                                          exit;
                                       end;
                                    end if;

                                    Lib_Dirs := Library_Dir.Next;
                                 end loop;

                                 if Version /= No_Name then
                                    Lang_Index.Config.
                                      Runtime_Library_Version := Version;
                                 else
                                    Lang_Index.Config.
                                      Runtime_Library_Version :=
                                      Lang_Index.Config.Toolchain_Version;
                                 end if;

                                 Shared.Ada_Runtime_Dir := Element.Value.Value;
                                 Shared.Ada_Runtime_Library_Dirs :=
                                   Lang_Index.Config.Runtime_Library_Dirs;
                                 Shared.Ada_Runtime_Source_Dirs :=
                                   Lang_Index.Config.Runtime_Source_Dirs;
                                 Shared.Ada_Runtime_Library_Version :=
                                   Lang_Index.Config.Runtime_Library_Version;
                              end;
                           end if;
                        end if;
                     end;

                  elsif Current_Array.Name = Name_Runtime_Library_Version then

                     --  Attribute Runtime_Library_Version (<language>)

                     Lang_Index.Config.Runtime_Library_Version :=
                       Element.Value.Value;

                  elsif Current_Array.Name = Name_Object_Generated then
                     declare
                        pragma Unsuppress (All_Checks);
                        Value : Boolean;

                     begin
                        Value :=
                          Boolean'Value
                            (Get_Name_String (Element.Value.Value));

                        Lang_Index.Config.Object_Generated := Value;

                        --  If no object is generated, no object may be
                        --  linked.

                        if not Value then
                           Lang_Index.Config.Objects_Linked := False;
                        end if;

                     exception
                        when Constraint_Error =>
                           Error_Msg
                             (Data.Flags,
                              "invalid value """
                              & Get_Name_String (Element.Value.Value)
                              & """ for Object_Generated",
                              Element.Value.Location, Project);
                     end;

                  elsif Current_Array.Name = Name_Objects_Linked then
                     declare
                        pragma Unsuppress (All_Checks);
                        Value : Boolean;

                     begin
                        Value :=
                          Boolean'Value
                            (Get_Name_String (Element.Value.Value));

                        --  No change if Object_Generated is False, as this
                        --  forces Objects_Linked to be False too.

                        if Lang_Index.Config.Object_Generated then
                           Lang_Index.Config.Objects_Linked := Value;
                        end if;

                     exception
                        when Constraint_Error =>
                           Error_Msg
                             (Data.Flags,
                              "invalid value """
                              & Get_Name_String (Element.Value.Value)
                              & """ for Objects_Linked",
                              Element.Value.Location, Project);
                     end;

                  elsif Current_Array.Name = Name_Only_Dirs_With_Sources then
                     declare
                        pragma Unsuppress (All_Checks);
                        Value : Boolean;

                     begin
                        Value :=
                          Boolean'Value
                            (Get_Name_String (Element.Value.Value));

                        --  No change if Object_Generated is False, as this
                        --  forces Objects_Linked to be False too.

                        Lang_Index.Config.Only_Dirs_With_Sources := Value;

                     exception
                        when Constraint_Error =>
                           Error_Msg
                             (Data.Flags,
                              "invalid value """
                              & Get_Name_String (Element.Value.Value)
                              & """ for Only_Dirs_With_Sources",
                              Element.Value.Location, Project);
                     end;
                  end if;
               end if;

               Element_Id := Element.Next;
            end loop;

            Current_Array_Id := Current_Array.Next;
         end loop;
      end Process_Project_Level_Array_Attributes;

   --  Start of processing for Check_Configuration

   begin
      Process_Project_Level_Simple_Attributes;
      Process_Project_Level_Array_Attributes;
      Process_Packages;

      --  For unit based languages, set Casing, Dot_Replacement and
      --  Separate_Suffix in Naming_Data.

      Lang_Index := Project.Languages;
      while Lang_Index /= No_Language_Index loop
         if Lang_Index.Config.Required_Toolchain_Version /= No_Name
           and then Lang_Index.Config.Toolchain_Version /=
             Lang_Index.Config.Required_Toolchain_Version
         then
            declare
               function No_GNAT_Prefix (Id : Name_Id) return String;
               --  Returns version string without "GNAT " prefix for Ada
               --  language if prefix exists. Returns version string as is for
               --  non Ada languages.

               --------------------
               -- No_GNAT_Prefix --
               --------------------

               function No_GNAT_Prefix (Id : Name_Id) return String is
                  Result : constant String := Get_Name_String_Or_Null (Id);
               begin
                  if Lang_Index.Name = Name_Ada
                    and then Starts_With (Result, GNAT_And_Space)
                  then
                     return Result
                       (Result'First + GNAT_And_Space'Length .. Result'Last);
                  else
                     return Result;
                  end if;
               end No_GNAT_Prefix;

               TVC : constant String :=
                       No_GNAT_Prefix (Lang_Index.Config.Toolchain_Version);
               TVR : constant String :=
                       No_GNAT_Prefix
                         (Lang_Index.Config.Required_Toolchain_Version);
            begin
               if TVC /= TVR then
                  Error_Msg
                    (Data.Flags,
                     "Toolchain version "
                     & (if TVC = "" then "" else '"' & TVC & """ ")
                     & "for language "
                     & Get_Name_String (Lang_Index.Name)
                     & " differs from the required one """ & TVR & '"',
                     No_Location, Project);
               end if;
            end;
         end if;

         if Lang_Index.Config.Kind = Unit_Based then
            Lang_Index.Config.Naming_Data.Casing := Casing;
            Lang_Index.Config.Naming_Data.Dot_Replacement := Dot_Replacement;

            if Separate_Suffix /= No_File then
               Lang_Index.Config.Naming_Data.Separate_Suffix :=
                 Separate_Suffix;
            end if;

            exit;
         end if;

         Lang_Index := Lang_Index.Next;
      end loop;

      --  Give empty names to various prefixes/suffixes, if they have not
      --  been specified in the configuration.

      if Project.Config.Archive_Suffix = No_File then
         Project.Config.Archive_Suffix := Empty_File;
      end if;

      if Project.Config.Shared_Lib_Prefix = No_File then
         Project.Config.Shared_Lib_Prefix := Empty_File;
      end if;

      if Project.Config.Shared_Lib_Suffix = No_File then
         Project.Config.Shared_Lib_Suffix := Empty_File;
      end if;

      Lang_Index := Project.Languages;
      while Lang_Index /= No_Language_Index loop
         if Is_Allowed_Language (Lang_Index.Name) then
            --  For all languages, Compiler_Driver should be specified. But
            --  there is no warning if it is not, as there may not be any
            --  source of the language. If there is such a source, then an
            --  error will be reported when trying to compile this source.

            if Lang_Index.Config.Compiler_Driver /= No_File
              or else Project.Externally_Built
              or else not Is_Allowed_Language (Lang_Index.Name)
            then
               if Lang_Index.Config.Kind = Unit_Based then
                  --  For unit based languages, Dot_Replacement, Spec_Suffix
                  --  and Body_Suffix need to be specified.

                  if Lang_Index.Config.Naming_Data.Dot_Replacement = No_File
                  then
                     Error_Msg
                       (Data.Flags,
                        "Dot_Replacement not specified for "
                        & Get_Name_String (Lang_Index.Name),
                        No_Location, Project);
                  end if;

                  if Lang_Index.Config.Naming_Data.Spec_Suffix = No_File then
                     Error_Msg
                       (Data.Flags,
                        "\Spec_Suffix not specified for "
                        & Get_Name_String (Lang_Index.Name),
                        No_Location, Project);
                  end if;

                  if Lang_Index.Config.Naming_Data.Body_Suffix = No_File then
                     Error_Msg
                       (Data.Flags,
                        "\Body_Suffix not specified for "
                        & Get_Name_String (Lang_Index.Name),
                        No_Location, Project);
                  end if;

               else
                  --  For file based languages, either Spec_Suffix or
                  --  Body_Suffix need to be specified.

                  if Data.Flags.Require_Sources_Other_Lang
                    and then
                      Lang_Index.Config.Naming_Data.Spec_Suffix = No_File
                    and then
                      Lang_Index.Config.Naming_Data.Body_Suffix = No_File
                  then
                     Error_Msg_Name_1 := Lang_Index.Display_Name;
                     Error_Msg
                       (Data.Flags,
                        "\no suffixes specified for %%",
                        No_Location, Project);
                  end if;
               end if;
            end if;
         end if;

         Lang_Index := Lang_Index.Next;
      end loop;
   end Check_Configuration;

   -------------------------------
   -- Check_If_Externally_Built --
   -------------------------------

   procedure Check_If_Externally_Built
     (Project : Project_Id;
      Data    : in out Tree_Processing_Data)
   is
      Shared   : constant Shared_Project_Tree_Data_Access := Data.Tree.Shared;
      Externally_Built : constant Variable_Value :=
                           Util.Value_Of
                            (Name_Externally_Built,
                             Project.Decl.Attributes, Shared);

   begin
      if not Externally_Built.Default then
         declare
            Lower_Value : constant String :=
                            To_Lower
                              (Get_Name_String (Externally_Built.Value));
         begin
            if Lower_Value = "true" then
               Project.Externally_Built := True;

            elsif Lower_Value /= "false" then
               Error_Msg
                 (Data.Flags,
                  "Externally_Built may only be true or false",
                  Externally_Built.Location, Project);
            end if;
         end;
      end if;

      --  A virtual project extending an externally built project is itself
      --  externally built.

      if Project.Virtual and then Project.Extends /= No_Project then
         Project.Externally_Built := Project.Extends.Externally_Built;
      end if;

      if Project.Externally_Built then
         Debug_Output ("project is externally built");
      else
         Debug_Output ("project is not externally built");
      end if;
   end Check_If_Externally_Built;

   ----------------------
   -- Check_Interfaces --
   ----------------------

   procedure Check_Interfaces
     (Project : Project_Id;
      Data    : in out Tree_Processing_Data)
   is
      Shared : constant Shared_Project_Tree_Data_Access := Data.Tree.Shared;

      Interfaces : constant GPR.Variable_Value :=
                     GPR.Util.Value_Of
                       (Snames.Name_Interfaces,
                        Project.Decl.Attributes,
                        Shared);

      Library_Interface : constant GPR.Variable_Value :=
                            GPR.Util.Value_Of
                              (Snames.Name_Library_Interface,
                               Project.Decl.Attributes,
                               Shared);

      List       : String_List_Id;
      Element    : String_Element;
      Name       : File_Name_Type;
      Iter       : Source_Iterator;
      Source     : Source_Id;
      Project_2  : Project_Id;
      Other      : Source_Id;
      Unit_Found : Boolean;

      Interface_ALIs   : String_List_Id := Nil_String;
      Other_Interfaces : String_List_Id := Nil_String;

      procedure Init_Interfaces;
      --  Set In_Interfaces to False for all sources. It will be set to True
      --  later for the sources in the [Library_]Interface list.
      --  Set In_Interfaces to True for sources from --src-subdirs directory.

      procedure Append_Interface_ALIs;

      procedure Append_Interfaces
        (List : in out String_List_Id; Value, Display_Value : File_Name_Type);

      -----------------------
      -- Append_Interfaces --
      -----------------------

      procedure Append_Interfaces
        (List : in out String_List_Id; Value, Display_Value : File_Name_Type)
      is
      begin
         String_Element_Table.Increment_Last (Shared.String_Elements);

         Shared.String_Elements.Table
           (String_Element_Table.Last (Shared.String_Elements)) :=
             (Value         => Name_Id (Value),
              Index         => 0,
              Display_Value => Name_Id (Display_Value),
              Location      => No_Location,
              Next          => List);

         List := String_Element_Table.Last (Shared.String_Elements);
      end Append_Interfaces;

      ---------------------------
      -- Append_Interface_ALIs --
      ---------------------------

      procedure Append_Interface_ALIs is
         Src : Source_Id;
      begin
         if Source.Kind = Spec then
            Src := Other_Part (Source);
         end if;

         if Src = No_Source then
            Src := Source;
         end if;

         Append_Interfaces (Interface_ALIs, Src.Dep_Name, Src.Dep_Name);
      end Append_Interface_ALIs;

      ---------------------
      -- Init_Interfaces --
      ---------------------

      procedure Init_Interfaces is
      begin
         Project_2 := Project;
         while Project_2 /= No_Project loop
            Iter := For_Each_Source (Data.Tree, Project_2);
            loop
               Source := GPR.Element (Iter);
               exit when Source = No_Source;

               if Source.In_Src_Subdir then
                  Append_Interface_ALIs;
               else
                  Source.In_Interfaces := False;
               end if;

               Next (Iter);
            end loop;

            Project_2 := Project_2.Extends;
         end loop;
      end Init_Interfaces;

   begin
      if not Interfaces.Default then
         Init_Interfaces;

         List := Interfaces.Values;
         while List /= Nil_String loop
            Element := Shared.String_Elements.Table (List);
            Name := Canonical_Case_File_Name (Element.Value);

            Project_2 := Project;
            Big_Loop : while Project_2 /= No_Project loop
               if Project.Qualifier = Aggregate_Library then

                  --  For an aggregate library we want to consider sources of
                  --  all aggregated projects.

                  Iter := For_Each_Source (Data.Tree);

               else
                  Iter := For_Each_Source (Data.Tree, Project_2);
               end if;

               loop
                  Source := GPR.Element (Iter);
                  exit when Source = No_Source;

                  if Source.File = Name then
                     if not Source.Locally_Removed then
                        Source.In_Interfaces := True;
                        Source.Declared_In_Interfaces := True;

                        Other := Other_Part (Source);

                        if Other /= No_Source then
                           Other.In_Interfaces := True;
                           Other.Declared_In_Interfaces := True;
                        end if;

                        --  Unit based case

                        if Source.Language.Config.Kind = Unit_Based then
                           Append_Interface_ALIs;

                        --  File based case

                        else
                           Append_Interfaces
                             (Other_Interfaces,
                              Source.File, Source.Display_File);
                        end if;

                        Debug_Output
                          ("interface: ", Name_Id (Source.Path.Name));
                     end if;

                     exit Big_Loop;
                  end if;

                  Next (Iter);
               end loop;

               Project_2 := Project_2.Extends;
            end loop Big_Loop;

            if Source = No_Source and then not Languages_Are_Restricted then
               Error_Msg_File_1 := File_Name_Type (Element.Value);
               Error_Msg_Name_1 := Project.Name;

               Error_Msg
                 (Data.Flags,
                  "{ cannot be an interface of project %% "
                  & "as it is not one of its sources",
                  Element.Location, Project);
            end if;

            List := Element.Next;
         end loop;

         Project.Interfaces_Defined := True;
         Project.Lib_Interface_ALIs := Interface_ALIs;
         Project.Other_Interfaces   := Other_Interfaces;

      elsif Project.Library and then not Library_Interface.Default then
         Init_Interfaces;

         List := Library_Interface.Values;
         while List /= Nil_String loop
            Element := Shared.String_Elements.Table (List);
            Name := File_Name_Type
              (Get_Lower_Name_Id (Get_Name_String (Element.Value)));
            Unit_Found := False;

            Project_2 := Project;
            Big_Loop_2 : while Project_2 /= No_Project loop
               if Project.Qualifier = Aggregate_Library then

                  --  For an aggregate library we want to consider sources of
                  --  all aggregated projects.

                  Iter := For_Each_Source (Data.Tree);

               else
                  Iter := For_Each_Source (Data.Tree, Project_2);
               end if;

               loop
                  Source := GPR.Element (Iter);
                  exit when Source = No_Source;

                  if Source.Unit /= No_Unit_Index
                    and then Source.Unit.Name = Name_Id (Name)
                  then
                     if not Source.Locally_Removed then
                        Source.In_Interfaces := True;
                        Source.Declared_In_Interfaces := True;
                        Project.Interfaces_Defined := True;

                        Other := Other_Part (Source);

                        if Other /= No_Source then
                           Other.In_Interfaces := True;
                           Other.Declared_In_Interfaces := True;
                        end if;

                        Debug_Output
                          ("interface: ", Name_Id (Source.Path.Name));

                        Append_Interface_ALIs;
                     end if;

                     Unit_Found := True;
                     exit Big_Loop_2;
                  end if;

                  Next (Iter);
               end loop;

               Project_2 := Project_2.Extends;
            end loop Big_Loop_2;

            if not Unit_Found then
               Error_Msg_Name_1 := Name_Id (Name);

               Error_Msg
                 (Data.Flags,
                  "%% is not a unit of this project",
                  Element.Location, Project);
            end if;

            List := Element.Next;
         end loop;

         Project.Lib_Interface_ALIs := Interface_ALIs;

      elsif Project.Extends /= No_Project
        and then Project.Extends.Interfaces_Defined
      then
         Project.Interfaces_Defined := True;

         Iter := For_Each_Source (Data.Tree, Project);
         loop
            Source := GPR.Element (Iter);
            exit when Source = No_Source;

            if not Source.Declared_In_Interfaces then
               Source.In_Interfaces := False;
            end if;

            Next (Iter);
         end loop;

         Project.Lib_Interface_ALIs := Project.Extends.Lib_Interface_ALIs;
      end if;
   end Check_Interfaces;

   ------------------------------
   -- Check_Library_Attributes --
   ------------------------------

   --  This procedure is awfully long (over 700 lines) should be broken up???

   procedure Check_Library_Attributes
     (Project    : Project_Id;
      No_Sources : Boolean;
      Data       : in out Tree_Processing_Data)
   is
      Shared : constant Shared_Project_Tree_Data_Access := Data.Tree.Shared;

      Attributes     : constant Variable_Id := Project.Decl.Attributes;

      Lib_Dir        : constant Variable_Value :=
                         GPR.Util.Value_Of
                           (Snames.Name_Library_Dir, Attributes, Shared);

      Lib_Name       : constant GPR.Variable_Value :=
                         GPR.Util.Value_Of
                           (Snames.Name_Library_Name, Attributes, Shared);

      Lib_Standalone : constant GPR.Variable_Value :=
                         GPR.Util.Value_Of
                           (Snames.Name_Library_Standalone,
                            Attributes, Shared);

      Lib_Version    : constant GPR.Variable_Value :=
                         GPR.Util.Value_Of
                           (Snames.Name_Library_Version, Attributes, Shared);

      Lib_ALI_Dir    : constant GPR.Variable_Value :=
                         GPR.Util.Value_Of
                           (Snames.Name_Library_Ali_Dir, Attributes, Shared);

      Lib_GCC        : constant GPR.Variable_Value :=
                         GPR.Util.Value_Of
                           (Snames.Name_Library_GCC, Attributes, Shared);

      The_Lib_Kind   : constant GPR.Variable_Value :=
                         GPR.Util.Value_Of
                           (Snames.Name_Library_Kind, Attributes, Shared);

      Imported_Project_List : Project_List;
      Continuation          : String_Access := No_Continuation_String'Access;
      Support_For_Libraries : Library_Support;

      Library_Directory_Present : Boolean;

      procedure Check_Library (Proj : Project_Id; Extends : Boolean);
      --  Check if an imported or extended project if also a library project

      procedure Check_Aggregate_Library_Dirs;
      --  Check that the library directory and the library ALI directory of an
      --  aggregate library project are not the same as the object directory or
      --  the library directory of any of its aggregated projects.

      ----------------------------------
      -- Check_Aggregate_Library_Dirs --
      ----------------------------------

      procedure Check_Aggregate_Library_Dirs is
         procedure Process_Aggregate (Proj : Project_Id);
         --  Recursive procedure to check the aggregated projects, as they may
         --  also be aggregated library projects.

         -----------------------
         -- Process_Aggregate --
         -----------------------

         procedure Process_Aggregate (Proj : Project_Id) is
            Agg : Aggregated_Project_List;

         begin
            Agg := Proj.Aggregated_Projects;
            while Agg /= null loop
               Error_Msg_Name_1 := Agg.Project.Name;

               if Agg.Project.Qualifier /= Aggregate_Library
                 and then Project.Library_ALI_Dir.Name =
                                        Agg.Project.Object_Directory.Name
               then
                  Error_Msg
                    (Data.Flags,
                     "aggregate library 'A'L'I directory cannot be shared with"
                     & " object directory of aggregated project %%",
                     The_Lib_Kind.Location, Project);

               elsif Project.Library_ALI_Dir.Name =
                                        Agg.Project.Library_Dir.Name
               then
                  Error_Msg
                    (Data.Flags,
                     "aggregate library 'A'L'I directory cannot be shared with"
                     & " library directory of aggregated project %%",
                     The_Lib_Kind.Location, Project);

               elsif Agg.Project.Qualifier /= Aggregate_Library
                 and then Project.Library_Dir.Name =
                                        Agg.Project.Object_Directory.Name
               then
                  Error_Msg
                    (Data.Flags,
                     "aggregate library directory cannot be shared with"
                     & " object directory of aggregated project %%",
                     The_Lib_Kind.Location, Project);

               elsif Project.Library_Dir.Name =
                                        Agg.Project.Library_Dir.Name
               then
                  Error_Msg
                    (Data.Flags,
                     "aggregate library directory cannot be shared with"
                     & " library directory of aggregated project %%",
                     The_Lib_Kind.Location, Project);
               end if;

               if Agg.Project.Qualifier = Aggregate_Library then
                  Process_Aggregate (Agg.Project);
               end if;

               Agg := Agg.Next;
            end loop;
         end Process_Aggregate;

      --  Start of processing for Check_Aggregate_Library_Dirs

      begin
         if Project.Qualifier = Aggregate_Library then
            Process_Aggregate (Project);
         end if;
      end Check_Aggregate_Library_Dirs;

      -------------------
      -- Check_Library --
      -------------------

      procedure Check_Library (Proj : Project_Id; Extends : Boolean) is
         Src_Id : Source_Id;
         Iter   : Source_Iterator;

      begin
         if Proj /= No_Project then
            if not Proj.Library then

               --  The only not library projects that are OK are those that
               --  have no sources. However, header files from non-Ada
               --  languages are OK, as there is nothing to compile.

               Iter := For_Each_Source (Data.Tree, Proj);
               loop
                  Src_Id := GPR.Element (Iter);
                  exit when Src_Id = No_Source
                    or else Src_Id.Language.Config.Kind /= File_Based
                    or else Src_Id.Kind /= Spec;
                  Next (Iter);
               end loop;

               if Src_Id /= No_Source then
                  Error_Msg_Name_1 := Project.Name;
                  Error_Msg_Name_2 := Proj.Name;

                  if Extends then
                     if Project.Library_Kind /= Static then
                        Error_Msg
                          (Data.Flags,
                           Continuation.all
                           & "shared library project %% cannot extend project"
                           & " %% that is not a library project",
                           Project.Location, Project);
                        Continuation := Continuation_String'Access;
                     end if;

                  elsif not Unchecked_Shared_Lib_Imports
                    and then Project.Library_Kind /= Static
                  then
                     Error_Msg
                       (Data.Flags,
                        Continuation.all
                        & "shared library project %% cannot import project %%"
                        & " that is not a shared library project",
                        Project.Location, Project);
                     Continuation := Continuation_String'Access;
                  end if;
               end if;

            elsif not Extends
              and then Project.Library_Kind /= Static
              and then not Lib_Standalone.Default
              and then
                To_Lower (Get_Name_String (Lib_Standalone.Value)) =
                  "encapsulated"
              and then Proj.Library_Kind in Relocatable | Dynamic
            then
               --  An encapsulated library must depend only on static libraries

               Error_Msg_Name_1 := Project.Name;
               Error_Msg_Name_2 := Proj.Name;

               Error_Msg
                 (Data.Flags,
                  Continuation.all
                  & "encapsulated library project %% cannot import shared "
                  & "library project %%",
                  Project.Location, Project);
               Continuation := Continuation_String'Access;

            elsif Project.Library_Kind /= Static
              and then Proj.Library_Kind = Static
              and then
                (Lib_Standalone.Default
                  or else
                 To_Lower (Get_Name_String (Lib_Standalone.Value)) /=
                   "encapsulated")
            then
               Error_Msg_Name_1 := Project.Name;
               Error_Msg_Name_2 := Proj.Name;

               if Extends then
                  Error_Msg
                    (Data.Flags,
                     Continuation.all
                     & "shared library project %% cannot extend static"
                     & " library project %%",
                     Project.Location, Project);
                  Continuation := Continuation_String'Access;

               elsif not Unchecked_Shared_Lib_Imports then
                  Error_Msg
                    (Data.Flags,
                     Continuation.all
                     & "shared library project %% cannot import static"
                     & " library project %%",
                     Project.Location, Project);
                  Continuation := Continuation_String'Access;
               end if;

            end if;
         end if;
      end Check_Library;

      Dir_Exists : Boolean;

   --  Start of processing for Check_Library_Attributes

   begin
      Library_Directory_Present := Lib_Dir.Value not in No_Name | Empty_String;

      --  Special case of extending project

      if Project.Extends /= No_Project then

         --  If the project extended is a library project, we inherit the
         --  library name, if it is not redefined; we check that the library
         --  directory is specified.

         if Project.Extends.Library then
            if Project.Qualifier = Standard then
               Error_Msg
                 (Data.Flags,
                  "a standard project cannot extend a library project",
                  Project.Location, Project);

            else
               if Lib_Name.Default then
                  Project.Library_Name := Project.Extends.Library_Name;
               end if;

               if Lib_Dir.Default then
                  if not Project.Virtual then
                     Error_Msg
                       (Data.Flags,
                        "a project extending a library project must specify an"
                        & " attribute Library_Dir",
                        Project.Location, Project);

                  else
                     --  For a virtual project extending a library project,
                     --  inherit library directory and library kind.

                     Project.Library_Dir := Project.Extends.Library_Dir;
                     Library_Directory_Present := True;
                     Project.Library_Kind := Project.Extends.Library_Kind;
                  end if;
               end if;
            end if;
         end if;
      end if;

      pragma Assert (Lib_Name.Kind = Single);

      if Lib_Name.Value = Empty_String then
         if Current_Verbosity = High
           and then Project.Library_Name = No_Name
         then
            Debug_Indent;
            Write_Line ("no library name");
         end if;

      else
         --  There is no restriction on the syntax of library names

         Project.Library_Name := Lib_Name.Value;
      end if;

      if Project.Library_Name /= No_Name then
         if Current_Verbosity = High then
            Write_Attr
              ("Library name: ", Get_Name_String (Project.Library_Name));
         end if;

         pragma Assert (Lib_Dir.Kind = Single);

         if not Library_Directory_Present then
            Debug_Output ("no library directory");

         else
            --  Find path name (unless inherited), check that it is a directory

            if Project.Library_Dir = No_Path_Information then
               Locate_Directory
                 (Project,
                  File_Name_Type (Lib_Dir.Value),
                  Path             => Project.Library_Dir,
                  Dir_Exists       => Dir_Exists,
                  Data             => Data,
                  Create           => "library",
                  Must_Exist       => False,
                  Location         => Lib_Dir.Location,
                  Externally_Built => Project.Externally_Built);

            else
               Dir_Exists :=
                 Is_Directory
                   (Get_Name_String (Project.Library_Dir.Display_Name));
            end if;

            if not Dir_Exists then
               if Directories_Must_Exist_In_Projects
                 and then Project.Qualifier /= Abstract_Project
               then

                  --  Get the absolute name of the library directory that does
                  --  not exist, to report an error.

                  Error_Msg_File_1 :=
                    File_Name_Type (Project.Library_Dir.Display_Name);
                  Error_Or_Warning
                    (Data.Flags, Data.Flags.Require_Obj_Dirs,
                     "library directory { does not exist",
                     Lib_Dir.Location, Project);
               end if;

            --  Checks for object/source directories

            elsif not Project.Externally_Built

              --  An aggregate library does not have sources or objects, so
              --  these tests are not required in this case.

              and then Project.Qualifier /= Aggregate_Library

              and then not No_Sources

            then
               --  Library directory cannot be the same as Object directory

               if Project.Library_Dir.Name = Project.Object_Directory.Name then
                  Error_Msg
                    (Data.Flags,
                     "library directory cannot be the same as object"
                     & " directory",
                     Lib_Dir.Location, Project);
                  Project.Library_Dir := No_Path_Information;

               else
                  declare
                     OK       : Boolean := True;
                     Dirs_Id  : String_List_Id;
                     Dir_Elem : String_Element;
                     Pid      : Project_List;

                  begin
                     --  The library directory cannot be the same as a source
                     --  directory of the current project.

                     Dirs_Id := Project.Source_Dirs;
                     while Dirs_Id /= Nil_String loop
                        Dir_Elem := Shared.String_Elements.Table (Dirs_Id);
                        Dirs_Id  := Dir_Elem.Next;

                        if Project.Library_Dir.Name =
                          Path_Name_Type (Dir_Elem.Value)
                        then
                           Error_Msg_File_1 :=
                             File_Name_Type (Dir_Elem.Value);
                           Error_Msg
                             (Data.Flags,
                              "library directory cannot be the same as source"
                              & " directory {",
                              Lib_Dir.Location, Project);
                           OK := False;
                           exit;
                        end if;
                     end loop;

                     if OK then

                        --  The library directory cannot be the same as a
                        --  source directory of another project either.

                        Pid := Data.Tree.Projects;
                        Project_Loop : loop
                           exit Project_Loop when Pid = null;

                           if Pid.Project /= Project then
                              Dirs_Id := Pid.Project.Source_Dirs;

                              Dir_Loop : while Dirs_Id /= Nil_String loop
                                 Dir_Elem :=
                                   Shared.String_Elements.Table (Dirs_Id);
                                 Dirs_Id  := Dir_Elem.Next;

                                 if Project.Library_Dir.Name =
                                   Path_Name_Type (Dir_Elem.Value)
                                 then
                                    Error_Msg_File_1 :=
                                      File_Name_Type (Dir_Elem.Value);
                                    Error_Msg_Name_1 :=
                                      Pid.Project.Name;

                                    Error_Msg
                                      (Data.Flags,
                                       "library directory cannot be the same"
                                       & " as source directory { of project"
                                       & " %%",
                                       Lib_Dir.Location, Project);
                                    OK := False;
                                    exit Project_Loop;
                                 end if;
                              end loop Dir_Loop;
                           end if;

                           Pid := Pid.Next;
                        end loop Project_Loop;
                     end if;

                     if not OK then
                        Project.Library_Dir := No_Path_Information;

                     elsif Current_Verbosity = High then

                        --  Display the Library directory in high verbosity

                        Write_Attr
                          ("Library directory",
                           Get_Name_String (Project.Library_Dir.Display_Name));
                     end if;
                  end;
               end if;
            end if;
         end if;

      end if;

      Project.Library :=
        Project.Library_Dir /= No_Path_Information
          and then Project.Library_Name /= No_Name;

      if Project.Library and then No_Sources then
         Project.Library := False;
         Project.Library_Dir := No_Path_Information;
         Project.Library_Name := No_Name;
         Error_Msg
           (Data.Flags,
            "a project with no sources cannot be a library project",
            Project.Location, Project);
         return;

      elsif Project.Extends = No_Project then
         case Project.Qualifier is
            when Standard =>
               if Project.Library then
                  Error_Msg
                    (Data.Flags,
                     "a standard project cannot be a library project",
                     Lib_Name.Location, Project);
               end if;

            when Library | Aggregate_Library =>
               if not Project.Library then
                  if Project.Library_Name = No_Name then
                     Error_Msg
                       (Data.Flags,
                        "attribute Library_Name not declared",
                        Project.Location, Project);

                     if not Library_Directory_Present then
                        Error_Msg
                          (Data.Flags,
                           "\attribute Library_Dir not declared",
                           Project.Location, Project);
                     end if;

                  elsif Project.Library_Dir = No_Path_Information then
                     Error_Msg
                       (Data.Flags,
                        "attribute Library_Dir not declared",
                        Project.Location, Project);
                  end if;
               end if;

            when others =>
               null;
         end case;
      end if;

      if Project.Library then
         Support_For_Libraries := Project.Config.Lib_Support;

         if not Project.Externally_Built
           and then Support_For_Libraries = GPR.None
         then
            Error_Msg
              (Data.Flags,
               "?libraries are not supported on this platform",
               Lib_Name.Location, Project);
            Project.Library := False;

         else
            if Lib_ALI_Dir.Value = Empty_String then
               Debug_Output ("no library ALI directory specified");
               Project.Library_ALI_Dir := Project.Library_Dir;

            else
               --  Find path name, check that it is a directory

               Locate_Directory
                 (Project,
                  File_Name_Type (Lib_ALI_Dir.Value),
                  Path             => Project.Library_ALI_Dir,
                  Create           => "library ALI",
                  Dir_Exists       => Dir_Exists,
                  Data             => Data,
                  Must_Exist       => False,
                  Location         => Lib_ALI_Dir.Location,
                  Externally_Built => Project.Externally_Built);

               if not Dir_Exists and then
                  Opt.Directories_Must_Exist_In_Projects
               then
                  --  Get the absolute name of the library ALI directory that
                  --  does not exist, to report an error.

                  Error_Msg_File_1 :=
                    File_Name_Type (Project.Library_ALI_Dir.Display_Name);
                  Error_Or_Warning
                    (Data.Flags, Data.Flags.Require_Obj_Dirs,
                     "library 'A'L'I directory { does not exist",
                     Lib_ALI_Dir.Location, Project);
               end if;

               if not Project.Externally_Built
                 and then Project.Library_ALI_Dir /= Project.Library_Dir
               then
                  --  The library ALI directory cannot be the same as the
                  --  Object directory.

                  if Project.Library_ALI_Dir = Project.Object_Directory then
                     Error_Msg
                       (Data.Flags,
                        "library 'A'L'I directory cannot be the same as object"
                        & " directory",
                        Lib_ALI_Dir.Location, Project);
                     Project.Library_ALI_Dir := No_Path_Information;

                  else
                     declare
                        OK       : Boolean := True;
                        Dirs_Id  : String_List_Id;
                        Dir_Elem : String_Element;
                        Pid      : Project_List;

                     begin
                        --  The library ALI directory cannot be the same as
                        --  a source directory of the current project.

                        Dirs_Id := Project.Source_Dirs;
                        while Dirs_Id /= Nil_String loop
                           Dir_Elem := Shared.String_Elements.Table (Dirs_Id);
                           Dirs_Id  := Dir_Elem.Next;

                           if Project.Library_ALI_Dir.Name =
                             Path_Name_Type (Dir_Elem.Value)
                           then
                              Error_Msg_File_1 :=
                                File_Name_Type (Dir_Elem.Value);
                              Error_Msg
                                (Data.Flags,
                                 "library 'A'L'I directory cannot be the same"
                                 & " as source directory {",
                                 Lib_ALI_Dir.Location, Project);
                              OK := False;
                              exit;
                           end if;
                        end loop;

                        if OK then

                           --  The library ALI directory cannot be the same as
                           --  a source directory of another project either.

                           Pid := Data.Tree.Projects;
                           ALI_Project_Loop : loop
                              exit ALI_Project_Loop when Pid = null;

                              if Pid.Project /= Project then
                                 Dirs_Id := Pid.Project.Source_Dirs;

                                 ALI_Dir_Loop :
                                 while Dirs_Id /= Nil_String loop
                                    Dir_Elem :=
                                      Shared.String_Elements.Table (Dirs_Id);
                                    Dirs_Id  := Dir_Elem.Next;

                                    if Project.Library_ALI_Dir.Name =
                                        Path_Name_Type (Dir_Elem.Value)
                                    then
                                       Error_Msg_File_1 :=
                                         File_Name_Type (Dir_Elem.Value);
                                       Error_Msg_Name_1 :=
                                         Pid.Project.Name;

                                       Error_Msg
                                         (Data.Flags,
                                          "library 'A'L'I directory cannot be"
                                          & " the same as source directory {"
                                          & " of project %%",
                                          Lib_ALI_Dir.Location, Project);
                                       OK := False;
                                       exit ALI_Project_Loop;
                                    end if;
                                 end loop ALI_Dir_Loop;
                              end if;
                              Pid := Pid.Next;
                           end loop ALI_Project_Loop;
                        end if;

                        if not OK then
                           Project.Library_ALI_Dir := No_Path_Information;

                        elsif Current_Verbosity = High then

                           --  Display Library ALI directory in high verbosity

                           Write_Attr
                             ("Library ALI dir",
                              Get_Name_String
                                (Project.Library_ALI_Dir.Display_Name));
                        end if;
                     end;
                  end if;
               end if;
            end if;

            pragma Assert (Lib_Version.Kind = Single);

            if Lib_Version.Value = Empty_String or else
              not Project.Config.Symbolic_Link_Supported
            then
               Debug_Output ("no library version specified");

            else
               Project.Lib_Internal_Name := Lib_Version.Value;
            end if;

            pragma Assert (The_Lib_Kind.Kind = Single);

            if The_Lib_Kind.Value = Empty_String then
               Debug_Output ("no library kind specified");

            elsif The_Lib_Kind.Value = No_Name then
               Error_Msg
                 (Data.Flags,
                  "incorrect value specified for library kind",
                  The_Lib_Kind.Location, Project);
               Project.Library := False;

            else
               Get_Name_String (The_Lib_Kind.Value);

               declare
                  Kind_Name : constant String :=
                                To_Lower (Name_Buffer (1 .. Name_Len));

                  OK : Boolean := True;

               begin
                  if Kind_Name = "static" then
                     Project.Library_Kind := Static;

                  elsif Kind_Name = "static-pic" then
                     Project.Library_Kind := Static_Pic;

                  elsif Kind_Name = "dynamic" then
                     Project.Library_Kind := Dynamic;

                  elsif Kind_Name = "relocatable" then
                     Project.Library_Kind := Relocatable;

                  else
                     Error_Msg
                       (Data.Flags,
                        "illegal value for Library_Kind",
                        The_Lib_Kind.Location, Project);
                     OK := False;
                  end if;

                  if Current_Verbosity = High and then OK then
                     Write_Attr ("Library kind", Kind_Name);
                  end if;

                  if Project.Library_Kind /= Static then
                     if not Project.Externally_Built
                       and then Support_For_Libraries = GPR.Static_Only
                     then
                        Error_Msg
                          (Data.Flags,
                           "only static libraries are supported on this"
                           & " platform",
                           The_Lib_Kind.Location, Project);
                        Project.Library := False;

                     else
                        --  Check if (obsolescent) attribute Library_GCC or
                        --  Linker'Driver is declared.

                        if Lib_GCC.Value /= Empty_String then
                           Error_Msg
                             (Data.Flags,
                              "?Library_'G'C'C is an obsolescent attribute, "
                              & "use Linker''Driver instead",
                              Lib_GCC.Location, Project);
                           Project.Config.Shared_Lib_Driver :=
                             File_Name_Type (Lib_GCC.Value);

                        else
                           declare
                              Linker : constant Package_Id :=
                                         Value_Of
                                           (Name_Linker,
                                            Project.Decl.Packages,
                                            Shared);
                              Driver : constant Variable_Value :=
                                         Value_Of
                                           (Name                 => No_Name,
                                            Attribute_Or_Array_Name =>
                                              Name_Driver,
                                            In_Package           => Linker,
                                            Shared               => Shared);

                           begin
                              if Driver /= Nil_Variable_Value
                                 and then Driver.Value /= Empty_String
                              then
                                 Project.Config.Shared_Lib_Driver :=
                                   File_Name_Type (Driver.Value);
                              end if;
                           end;
                        end if;
                     end if;
                  end if;
               end;
            end if;

            if Project.Library
              and then Project.Qualifier /= Aggregate_Library
            then
               Debug_Output ("this is a library project file");

               Check_Library (Project.Extends, Extends => True);

               Compute_All_Imported_Projects (Project, Data.Tree);
               Imported_Project_List := Project.All_Imported_Projects;
               while Imported_Project_List /= null loop
                  Check_Library
                    (Imported_Project_List.Project,
                     Extends => False);
                  Imported_Project_List := Imported_Project_List.Next;
               end loop;
            end if;
         end if;
      end if;

      --  Check if Linker'Switches or Linker'Default_Switches are declared.
      --  Warn if they are declared, as it is a common error to think that
      --  library are "linked" with Linker switches.

      if Project.Library then
         declare
            Linker_Package_Id : constant Package_Id :=
                                  Util.Value_Of
                                    (Name_Linker,
                                     Project.Decl.Packages, Shared);
            Linker_Package    : Package_Element;
            Switches          : Array_Element_Id := No_Array_Element;

         begin
            if Linker_Package_Id /= No_Package then
               Linker_Package := Shared.Packages.Table (Linker_Package_Id);

               Switches :=
                 Value_Of
                   (Name      => Name_Switches,
                    In_Arrays => Linker_Package.Decl.Arrays,
                    Shared    => Shared);

               if Switches = No_Array_Element then
                  Switches :=
                    Value_Of
                      (Name      => Name_Default_Switches,
                       In_Arrays => Linker_Package.Decl.Arrays,
                       Shared    => Shared);
               end if;

               if Switches /= No_Array_Element then
                  Error_Msg
                    (Data.Flags,
                     "?\Linker switches not taken into account in library "
                     & "projects",
                     No_Location, Project);
               end if;
            end if;
         end;
      end if;

      if Project.Extends /= No_Project and then Project.Extends.Library then

         --  Remove the library name from Lib_Data_Table

         for J in 1 .. Lib_Data_Table.Last loop
            if Lib_Data_Table.Table (J).Proj = Project.Extends then
               Lib_Data_Table.Table (J) :=
                 Lib_Data_Table.Table (Lib_Data_Table.Last);
               Lib_Data_Table.Set_Last (Lib_Data_Table.Last - 1);
               exit;
            end if;
         end loop;
      end if;

      if Project.Library and then not Lib_Name.Default then

         --  Check if the same library name is used in an other library project

         for J in 1 .. Lib_Data_Table.Last loop
            if Lib_Data_Table.Table (J).Name = Project.Library_Name
              and then Lib_Data_Table.Table (J).Tree = Data.Tree
            then
               Error_Msg_Name_1 := Lib_Data_Table.Table (J).Proj.Display_Name;
               Error_Msg
                 (Data.Flags,
                  "Library name cannot be the same as in project %%",
                  Lib_Name.Location, Project);
               Project.Library := False;
            end if;
         end loop;
      end if;

      --  Check that aggregated libraries do not share the aggregate
      --  Library_ALI_Dir.

      if Project.Qualifier = Aggregate_Library then
         Check_Aggregate_Library_Dirs;
      end if;

      if Project.Library and not Data.In_Aggregate_Lib then
         --  Record the library name

         Lib_Data_Table.Append
           ((Name => Project.Library_Name,
             Proj => Project,
             Tree => Data.Tree));
      end if;
   end Check_Library_Attributes;

   --------------------------
   -- Check_Package_Naming --
   --------------------------

   procedure Check_Package_Naming
     (Project : Project_Id;
      Data    : in out Tree_Processing_Data)
   is
      Shared    : constant Shared_Project_Tree_Data_Access := Data.Tree.Shared;
      Naming_Id : constant Package_Id :=
                    Util.Value_Of
                      (Name_Naming, Project.Decl.Packages, Shared);
      Naming    : Package_Element;

      Ada_Body_Suffix_Loc : Source_Ptr := No_Location;

      procedure Check_Naming;
      --  Check the validity of the Naming package (suffixes valid, ...)

      procedure Check_Common
        (Dot_Replacement : in out File_Name_Type;
         Casing          : in out Casing_Type;
         Casing_Defined  : out Boolean;
         Separate_Suffix : in out File_Name_Type;
         Sep_Suffix_Loc  : out Source_Ptr);
      --  Check attributes common

      procedure Process_Exceptions_File_Based
        (Lang_Id : Language_Ptr;
         Kind    : Source_Kind);
      procedure Process_Exceptions_Unit_Based
        (Lang_Id : Language_Ptr;
         Kind    : Source_Kind);
      --  Process the naming exceptions for the two types of languages

      procedure Initialize_Naming_Data;
      --  Initialize internal naming data for the various languages

      ------------------
      -- Check_Common --
      ------------------

      procedure Check_Common
        (Dot_Replacement : in out File_Name_Type;
         Casing          : in out Casing_Type;
         Casing_Defined  : out Boolean;
         Separate_Suffix : in out File_Name_Type;
         Sep_Suffix_Loc  : out Source_Ptr)
      is
         Dot_Repl      : constant Variable_Value :=
                           Util.Value_Of
                             (Name_Dot_Replacement,
                              Naming.Decl.Attributes,
                              Shared);
         Casing_String : constant Variable_Value :=
                           Util.Value_Of
                             (Name_Casing,
                              Naming.Decl.Attributes,
                              Shared);
         Sep_Suffix    : constant Variable_Value :=
                           Util.Value_Of
                             (Name_Separate_Suffix,
                              Naming.Decl.Attributes,
                              Shared);
         Dot_Repl_Loc  : Source_Ptr;

      begin
         Sep_Suffix_Loc := No_Location;

         if not Dot_Repl.Default and then Dot_Repl.Value /= No_Name then
            pragma Assert
              (Dot_Repl.Kind = Single, "Dot_Replacement is not a string");

            if Dot_Repl.Value = Empty_String then
               Error_Msg
                 (Data.Flags, "Dot_Replacement cannot be empty",
                  Dot_Repl.Location, Project);
            end if;

            Dot_Replacement := Canonical_Case_File_Name (Dot_Repl.Value);
            Dot_Repl_Loc    := Dot_Repl.Location;

            declare
               Repl   : constant String := Get_Name_String (Dot_Replacement);
               Not_OK : Boolean;
               subtype Printable_ASCII is Character range '!' .. '~';

            begin
               --  Dot_Replacement cannot
               --   - be empty
               --   - start or end with an alphanumeric
               --   - be a single '_'
               --   - start with an '_' followed by an alphanumeric
               --   - contain a '.' except if it is "."

               Not_OK := Repl'Length = 0
                 or else Is_Alphanumeric (Repl (Repl'First))
                 or else Is_Alphanumeric (Repl (Repl'Last))
                 or else (Repl (Repl'First) = '_'
                           and then
                             (Repl'Length = 1
                               or else
                                 Is_Alphanumeric (Repl (Repl'First + 1))))
                 or else (Repl'Length > 1
                           and then
                          Index (Source => Repl, Pattern => ".") /= 0);

               --  Dot_Replacement cannot include any character that is not
               --  printable ASCII except space (' ').

               if not Not_OK then
                  for J in Repl'Range loop
                     if not (Repl (J) in Printable_ASCII) then
                        Not_OK := True;
                        exit;
                     end if;
                  end loop;
               end if;

               if Not_OK then
                  Error_Msg
                    (Data.Flags,
                     '"' & Repl & """ is illegal for Dot_Replacement",
                     Dot_Repl_Loc, Project);
               end if;
            end;
         end if;

         if Dot_Replacement /= No_File then
            Write_Attr
              ("Dot_Replacement", Get_Name_String (Dot_Replacement));
         end if;

         Casing_Defined := False;

         if not Casing_String.Default
            and then Casing_String.Value /= No_Name
         then
            pragma Assert
              (Casing_String.Kind = Single, "Casing is not a string");

            declare
               Casing_Image : constant String :=
                                Get_Name_String (Casing_String.Value);

            begin
               if Casing_Image'Length = 0 then
                  Error_Msg
                    (Data.Flags,
                     "Casing cannot be an empty string",
                     Casing_String.Location, Project);
               end if;

               Casing := Value (Casing_Image);
               Casing_Defined := True;

            exception
               when Constraint_Error =>
                  Name_Len := Casing_Image'Length;
                  Name_Buffer (1 .. Name_Len) := Casing_Image;
                  Error_Msg_Name_1 := Name_Find;
                  Error_Msg
                    (Data.Flags,
                     "%% is not a correct Casing",
                     Casing_String.Location, Project);
            end;
         end if;

         Write_Attr ("Casing", Image (Casing));

         if not Sep_Suffix.Default then
            if Sep_Suffix.Value = Empty_String then
               Error_Msg
                 (Data.Flags,
                  "Separate_Suffix cannot be empty",
                  Sep_Suffix.Location, Project);

            else
               Separate_Suffix := Canonical_Case_File_Name (Sep_Suffix.Value);
               Sep_Suffix_Loc  := Sep_Suffix.Location;

               Check_Illegal_Suffix
                 (Project, Separate_Suffix,
                  Dot_Replacement, "Separate_Suffix", Sep_Suffix.Location,
                  Data);
            end if;
         end if;

         if Separate_Suffix /= No_File then
            Write_Attr
              ("Separate_Suffix", Get_Name_String (Separate_Suffix));
         end if;
      end Check_Common;

      -----------------------------------
      -- Process_Exceptions_File_Based --
      -----------------------------------

      procedure Process_Exceptions_File_Based
        (Lang_Id : Language_Ptr;
         Kind    : Source_Kind)
      is
         Lang           : constant Name_Id := Lang_Id.Name;
         Exceptions     : Array_Element_Id;
         Exception_List : Variable_Value;
         Element_Id     : String_List_Id;
         Element        : String_Element;
         File_Name      : File_Name_Type;
         Source         : Source_Id;

      begin
         case Kind is
            when Impl | Sep =>
               Exceptions :=
                 Value_Of
                   (Name_Implementation_Exceptions,
                    In_Arrays => Naming.Decl.Arrays,
                    Shared    => Shared);

            when Spec =>
               Exceptions :=
                 Value_Of
                   (Name_Specification_Exceptions,
                    In_Arrays => Naming.Decl.Arrays,
                    Shared    => Shared);
         end case;

         Exception_List :=
           Value_Of
             (Index    => Lang,
              In_Array => Exceptions,
              Shared   => Shared);

         if Exception_List /= Nil_Variable_Value then
            Element_Id := Exception_List.Values;
            while Element_Id /= Nil_String loop
               Element   := Shared.String_Elements.Table (Element_Id);
               File_Name := Canonical_Case_File_Name (Element.Value);

               Source :=
                 Source_Files_Htable.Get
                   (Data.Tree.Source_Files_HT, File_Name);
               while Source /= No_Source
                 and then Source.Project /= Project
               loop
                  Source := Source.Next_With_File_Name;
               end loop;

               if Source = No_Source then
                  Add_Source
                    (Id               => Source,
                     Data             => Data,
                     Project          => Project,
                     Source_Dir_Rank  => 0,
                     Lang_Id          => Lang_Id,
                     Kind             => Kind,
                     File_Name        => File_Name,
                     Display_File     => File_Name_Type (Element.Value),
                     Naming_Exception => Yes,
                     Location         => Element.Location);

               else
                  --  Check if the file name is already recorded for another
                  --  language or another kind.

                  if Source.Language /= Lang_Id then
                     Error_Msg
                       (Data.Flags,
                        "the same file cannot be a source of two languages",
                        Element.Location, Project);

                  elsif Source.Kind /= Kind then
                     Error_Msg
                       (Data.Flags,
                        "the same file cannot be a source and a template",
                        Element.Location, Project);
                  end if;

                  --  If the file is already recorded for the same
                  --  language and the same kind, it means that the file
                  --  name appears several times in the *_Exceptions
                  --  attribute; so there is nothing to do.
               end if;

               Element_Id := Element.Next;
            end loop;
         end if;
      end Process_Exceptions_File_Based;

      -----------------------------------
      -- Process_Exceptions_Unit_Based --
      -----------------------------------

      procedure Process_Exceptions_Unit_Based
        (Lang_Id : Language_Ptr;
         Kind    : Source_Kind)
      is
         Exceptions : Array_Element_Id;
         Element    : Array_Element;
         Unit       : Name_Id;
         Index      : Int;
         File_Name  : File_Name_Type;
         Source     : Source_Id;

         Naming_Exception : Naming_Exception_Type;

      begin
         case Kind is
            when Impl | Sep =>
               Exceptions :=
                 Value_Of
                   (Name_Body,
                    In_Arrays => Naming.Decl.Arrays,
                    Shared    => Shared);

               if Exceptions = No_Array_Element then
                  Exceptions :=
                    Value_Of
                      (Name_Implementation,
                       In_Arrays => Naming.Decl.Arrays,
                       Shared    => Shared);
               end if;

            when Spec =>
               Exceptions :=
                 Value_Of
                   (Name_Spec,
                    In_Arrays => Naming.Decl.Arrays,
                    Shared    => Shared);

               if Exceptions = No_Array_Element then
                  Exceptions :=
                    Value_Of
                      (Name_Specification,
                       In_Arrays => Naming.Decl.Arrays,
                       Shared    => Shared);
               end if;
         end case;

         while Exceptions /= No_Array_Element loop
            Element   := Shared.Array_Elements.Table (Exceptions);

            if Element.Restricted then
               Naming_Exception := Inherited;
            else
               Naming_Exception := Yes;
            end if;

            File_Name := Canonical_Case_File_Name (Element.Value.Value);

            Index := Element.Value.Index;

            --  Check if it is a valid unit name

            Check_Unit_Name (Get_Name_String (Element.Index), Unit);

            if Unit = No_Name then
               Error_Msg_Name_1 := Element.Index;
               Error_Msg
                 (Data.Flags,
                  "%% is not a valid unit name.",
                  Element.Value.Location, Project);
            end if;

            if Unit /= No_Name then
               Add_Source
                 (Id               => Source,
                  Data             => Data,
                  Project          => Project,
                  Source_Dir_Rank  => 0,
                  Lang_Id          => Lang_Id,
                  Kind             => Kind,
                  File_Name        => File_Name,
                  Display_File     => File_Name_Type (Element.Value.Value),
                  Unit             => Unit,
                  Index            => Index,
                  Location         => Element.Value.Location,
                  Naming_Exception => Naming_Exception);
            end if;

            Exceptions := Element.Next;
         end loop;
      end Process_Exceptions_Unit_Based;

      ------------------
      -- Check_Naming --
      ------------------

      procedure Check_Naming is
         Dot_Replacement : File_Name_Type :=
                             File_Name_Type
                               (First_Name_Id + Character'Pos ('-'));
         Separate_Suffix : File_Name_Type := No_File;
         Casing          : Casing_Type    := All_Lower_Case;
         Casing_Defined  : Boolean;
         Lang_Id         : Language_Ptr;
         Sep_Suffix_Loc  : Source_Ptr;
         Suffix          : Variable_Value;
         Lang            : Name_Id;

         function Name_Id_Hash (Key : Name_Id) return Ada.Containers.Hash_Type;

         function Name_Id_Hash (Key : Name_Id) return Ada.Containers.Hash_Type
         is
         begin
            return Ada.Strings.Hash_Case_Insensitive (Get_Name_String (Key));
         end Name_Id_Hash;

         function Name_Id_Equal_Case_Insensitive
           (Left, Right : Name_Id) return Boolean;

         function Name_Id_Equal_Case_Insensitive
           (Left, Right : Name_Id) return Boolean
         is
         begin
            return Ada.Strings.Equal_Case_Insensitive
              (Get_Name_String (Left), Get_Name_String (Right));
         end Name_Id_Equal_Case_Insensitive;

         package Suffix_Lang_Maps is new Ada.Containers.Hashed_Maps
           (Key_Type        => Name_Id,  --  Suffix
            Element_Type    => Name_Id,  --  Language
            Hash            => Name_Id_Hash,
            Equivalent_Keys => Name_Id_Equal_Case_Insensitive,
            "="             => Name_Id_Equal_Case_Insensitive);

         Suffix_Lang_Map : Suffix_Lang_Maps.Map;

         use type Suffix_Lang_Maps.Cursor;

      begin
         Check_Common
           (Dot_Replacement => Dot_Replacement,
            Casing          => Casing,
            Casing_Defined  => Casing_Defined,
            Separate_Suffix => Separate_Suffix,
            Sep_Suffix_Loc  => Sep_Suffix_Loc);

         --  For all unit based languages, if any, set the specified value
         --  of Dot_Replacement, Casing and/or Separate_Suffix. Do not
         --  systematically overwrite, since the defaults come from the
         --  configuration file.

         if Dot_Replacement /= No_File
           or else Casing_Defined
           or else Separate_Suffix /= No_File
         then
            Lang_Id := Project.Languages;
            while Lang_Id /= No_Language_Index loop
               if Lang_Id.Config.Kind = Unit_Based then
                  if Dot_Replacement /= No_File then
                     Lang_Id.Config.Naming_Data.Dot_Replacement :=
                         Dot_Replacement;
                  end if;

                  if Casing_Defined then
                     Lang_Id.Config.Naming_Data.Casing := Casing;
                  end if;
               end if;

               Lang_Id := Lang_Id.Next;
            end loop;
         end if;

         --  Next, get the spec and body suffixes

         Lang_Id := Project.Languages;
         while Lang_Id /= No_Language_Index loop
            Lang := Lang_Id.Name;

            --  Spec_Suffix

            Suffix := Value_Of
              (Name                    => Lang,
               Attribute_Or_Array_Name => Name_Spec_Suffix,
               In_Package              => Naming_Id,
               Shared                  => Shared);

            if Suffix = Nil_Variable_Value then
               Suffix := Value_Of
                 (Name                    => Lang,
                  Attribute_Or_Array_Name => Name_Specification_Suffix,
                  In_Package              => Naming_Id,
                  Shared                  => Shared);
            end if;

            if Suffix /= Nil_Variable_Value
              and then Suffix.Value /= No_Name
            then

               --  Check if there is an ambiguity for the spec suffix
               --  i.e. it is already associated (as a spec or body suffix)
               --  with another language.

               declare
                  Associated_Lang : constant Suffix_Lang_Maps.Cursor :=
                    Suffix_Lang_Map.Find (Key => Suffix.Value);
               begin
                  if Associated_Lang /= Suffix_Lang_Maps.No_Element then
                     Error_Msg
                       (Data.Flags,
                        "Spec_Suffix (""" & Get_Name_String (Suffix.Value)
                        & """) for language " & Get_Name_String (Lang_Id.Name)
                        & " is also defined for language "
                        & Get_Name_String (Suffix_Lang_Map (Suffix.Value))
                        & '.',
                        Suffix.Location, Project);
                  else
                     Suffix_Lang_Map.Include
                       (Key => Suffix.Value, New_Item => Lang_Id.Name);
                  end if;
               end;

               Lang_Id.Config.Naming_Data.Spec_Suffix :=
                 File_Name_Type (Suffix.Value);

               Check_Illegal_Suffix
                 (Project,
                  Lang_Id.Config.Naming_Data.Spec_Suffix,
                  Lang_Id.Config.Naming_Data.Dot_Replacement,
                  "Spec_Suffix", Suffix.Location, Data);

               Write_Attr
                 ("Spec_Suffix",
                  Get_Name_String (Lang_Id.Config.Naming_Data.Spec_Suffix));
            end if;

            --  Body_Suffix

            Suffix :=
              Value_Of
                (Name                    => Lang,
                 Attribute_Or_Array_Name => Name_Body_Suffix,
                 In_Package              => Naming_Id,
                 Shared                  => Shared);

            if Suffix = Nil_Variable_Value then
               Suffix :=
                 Value_Of
                   (Name                    => Lang,
                    Attribute_Or_Array_Name => Name_Implementation_Suffix,
                    In_Package              => Naming_Id,
                    Shared                  => Shared);
            end if;

            if Suffix /= Nil_Variable_Value
              and then Suffix.Value /= No_Name
            then

               --  Check if there is an ambiguity for the body suffix
               --  i.e. it is already associated (as a spec or body suffix)
               --  with another language.

               declare
                  Associated_Lang : constant Suffix_Lang_Maps.Cursor :=
                    Suffix_Lang_Map.Find (Key => Suffix.Value);
               begin
                  if Associated_Lang /= Suffix_Lang_Maps.No_Element then
                     Error_Msg
                       (Data.Flags,
                        "Body_Suffix (""" & Get_Name_String (Suffix.Value)
                        & """) for language " & Get_Name_String (Lang_Id.Name)
                        & " is also defined for language "
                        & Get_Name_String (Suffix_Lang_Map (Suffix.Value))
                        & '.',
                        Suffix.Location, Project);
                  else
                     Suffix_Lang_Map.Include (Key      => Suffix.Value,
                                              New_Item => Lang_Id.Name);
                  end if;
               end;

               Lang_Id.Config.Naming_Data.Body_Suffix :=
                 File_Name_Type (Suffix.Value);

               --  The default value of separate suffix should be the same as
               --  the body suffix, so we need to compute that first.

               if Separate_Suffix = No_File then
                  Lang_Id.Config.Naming_Data.Separate_Suffix :=
                    Lang_Id.Config.Naming_Data.Body_Suffix;
                  Write_Attr
                    ("Sep_Suffix",
                     Get_Name_String
                       (Lang_Id.Config.Naming_Data.Separate_Suffix));
               else
                  Lang_Id.Config.Naming_Data.Separate_Suffix :=
                    Separate_Suffix;
               end if;

               Check_Illegal_Suffix
                 (Project,
                  Lang_Id.Config.Naming_Data.Body_Suffix,
                  Lang_Id.Config.Naming_Data.Dot_Replacement,
                  "Body_Suffix", Suffix.Location, Data);

               Write_Attr
                 ("Body_Suffix",
                  Get_Name_String (Lang_Id.Config.Naming_Data.Body_Suffix));

            elsif Separate_Suffix /= No_File then
               Lang_Id.Config.Naming_Data.Separate_Suffix := Separate_Suffix;
            end if;

            --  Spec_Suffix cannot be equal to Body_Suffix or Separate_Suffix,
            --  since that would cause a clear ambiguity. Note that we do allow
            --  a Spec_Suffix to have the same termination as one of these,
            --  which causes a potential ambiguity, but we resolve that by
            --  matching the longest possible suffix.

            if Lang_Id.Config.Naming_Data.Spec_Suffix /= No_File
              and then Lang_Id.Config.Naming_Data.Spec_Suffix =
                       Lang_Id.Config.Naming_Data.Body_Suffix
            then
               Error_Msg
                 (Data.Flags,
                  "Body_Suffix ("""
                  & Get_Name_String (Lang_Id.Config.Naming_Data.Body_Suffix)
                  & """) cannot be the same as Spec_Suffix.",
                  Ada_Body_Suffix_Loc, Project);
            end if;

            if Lang_Id.Config.Naming_Data.Body_Suffix /=
               Lang_Id.Config.Naming_Data.Separate_Suffix
              and then Lang_Id.Config.Naming_Data.Spec_Suffix =
                       Lang_Id.Config.Naming_Data.Separate_Suffix
            then
               Error_Msg
                 (Data.Flags,
                  "Separate_Suffix ("""
                  & Get_Name_String
                      (Lang_Id.Config.Naming_Data.Separate_Suffix)
                  & """) cannot be the same as Spec_Suffix.",
                  Sep_Suffix_Loc, Project);
            end if;

            Lang_Id := Lang_Id.Next;
         end loop;

         --  Get the naming exceptions for all languages, but not for virtual
         --  projects.

         if not Project.Virtual and then Project.Source_Dirs /= Nil_String then
            for Kind in Spec_Or_Body loop
               Lang_Id := Project.Languages;
               while Lang_Id /= No_Language_Index loop
                  case Lang_Id.Config.Kind is
                  when File_Based =>
                     Process_Exceptions_File_Based (Lang_Id, Kind);

                  when Unit_Based =>
                     Process_Exceptions_Unit_Based (Lang_Id, Kind);
                  end case;

                  Lang_Id := Lang_Id.Next;
               end loop;
            end loop;
         end if;
      end Check_Naming;

      ----------------------------
      -- Initialize_Naming_Data --
      ----------------------------

      procedure Initialize_Naming_Data is
         Specs : Array_Element_Id :=
                   Util.Value_Of
                     (Name_Spec_Suffix,
                      Naming.Decl.Arrays,
                      Shared);

         Impls : Array_Element_Id :=
                   Util.Value_Of
                     (Name_Body_Suffix,
                      Naming.Decl.Arrays,
                      Shared);

         Lang      : Language_Ptr;
         Lang_Name : Name_Id;
         Value     : Variable_Value;
         Extended  : Project_Id;

      begin
         --  At this stage, the project already contains the default extensions
         --  for the various languages. We now merge those suffixes read in the
         --  user project, and they override the default.

         while Specs /= No_Array_Element loop
            Lang_Name := Shared.Array_Elements.Table (Specs).Index;
            Lang :=
              Get_Language_From_Name
                (Project, Name => Get_Name_String (Lang_Name));

            --  An extending project inherits its parent projects' languages
            --  so if needed we should create entries for those languages

            if Lang = null  then
               Extended := Project.Extends;
               while Extended /= null loop
                  Lang := Get_Language_From_Name
                    (Extended, Name => Get_Name_String (Lang_Name));
                  exit when Lang /= null;

                  Extended := Extended.Extends;
               end loop;

               if Lang /= null then
                  Lang := new Language_Data'(Lang.all);
                  Lang.First_Source := null;
                  Lang.Next := Project.Languages;
                  Project.Languages := Lang;
               end if;
            end if;

            --  If language was not found in project or the projects it extends

            if Lang = null then
               Debug_Output
                 ("ignoring spec naming data (lang. not in project): ",
                  Lang_Name);

            else
               Value := Shared.Array_Elements.Table (Specs).Value;

               if Value.Kind = Single then
                  Lang.Config.Naming_Data.Spec_Suffix :=
                    Canonical_Case_File_Name (Value.Value);
               end if;
            end if;

            Specs := Shared.Array_Elements.Table (Specs).Next;
         end loop;

         while Impls /= No_Array_Element loop
            Lang_Name := Shared.Array_Elements.Table (Impls).Index;
            Lang :=
              Get_Language_From_Name
                (Project, Name => Get_Name_String (Lang_Name));

            if Lang = null then
               Debug_Output
                 ("ignoring impl naming data (lang. not in project): ",
                  Lang_Name);
            else
               Value := Shared.Array_Elements.Table (Impls).Value;

               if Lang.Name = Name_Ada then
                  Ada_Body_Suffix_Loc := Value.Location;
               end if;

               if Value.Kind = Single then
                  Lang.Config.Naming_Data.Body_Suffix :=
                    Canonical_Case_File_Name (Value.Value);
               end if;
            end if;

            Impls := Shared.Array_Elements.Table (Impls).Next;
         end loop;
      end Initialize_Naming_Data;

   --  Start of processing for Check_Naming_Schemes

   begin
      --  No Naming package or parsing a configuration file? nothing to do

      if Naming_Id /= No_Package
        and then Project.Qualifier /= Configuration
      then
         Naming := Shared.Packages.Table (Naming_Id);
         Debug_Increase_Indent ("checking package Naming for ", Project.Name);
         Initialize_Naming_Data;
         Check_Naming;
         Debug_Decrease_Indent ("done checking package naming");
      end if;
   end Check_Package_Naming;

   ---------------------------------
   -- Check_Programming_Languages --
   ---------------------------------

   procedure Check_Programming_Languages
     (Project : Project_Id;
      Data    : in out Tree_Processing_Data)
   is
      Shared : constant Shared_Project_Tree_Data_Access := Data.Tree.Shared;

      Languages   : Variable_Value := Nil_Variable_Value;
      Def_Lang    : Variable_Value := Nil_Variable_Value;
      Def_Lang_Id : Name_Id;

      procedure Add_Language (Name, Display_Name : Name_Id);
      --  Add a new language to the list of languages for the project.
      --  Nothing is done if the language has already been defined

      ------------------
      -- Add_Language --
      ------------------

      procedure Add_Language (Name, Display_Name : Name_Id) is
         Lang : Language_Ptr;

      begin
         Lang := Project.Languages;
         while Lang /= No_Language_Index loop
            if Name = Lang.Name then
               return;
            end if;

            Lang := Lang.Next;
         end loop;

         Lang              := new Language_Data'(No_Language_Data);
         Lang.Next         := Project.Languages;
         Project.Languages := Lang;
         Lang.Name         := Name;
         Lang.Display_Name := Display_Name;
      end Add_Language;

   --  Start of processing for Check_Programming_Languages

   begin
      Project.Languages := null;
      Languages :=
        GPR.Util.Value_Of
          (Name_Languages, Project.Decl.Attributes, Shared);
      Def_Lang :=
        GPR.Util.Value_Of
          (Name_Default_Language, Project.Decl.Attributes, Shared);

         --  Check if languages are specified in this project

         if Languages.Default then

            --  Fail if there is no default language defined

            if Def_Lang.Default then
               Error_Msg
                 (Data.Flags,
                  "no languages defined for this project",
                  Project.Location, Project);
               Def_Lang_Id := No_Name;

            else
               Def_Lang_Id :=
                 Get_Lower_Name_Id (Get_Name_String (Def_Lang.Value));
            end if;

            if Def_Lang_Id /= No_Name then
               Get_Name_String (Def_Lang_Id);
               Name_Buffer (1) := To_Upper (Name_Buffer (1));
               Add_Language
                 (Name         => Def_Lang_Id,
                  Display_Name => Name_Find);
            end if;

         else
            declare
               Current : String_List_Id := Languages.Values;
               Element : String_Element;

            begin
               --  If there are no languages declared, there are no sources

               if Current = Nil_String then
                  Project.Source_Dirs := Nil_String;

                  if Project.Qualifier = Standard then
                     Error_Msg
                       (Data.Flags,
                        "a standard project must have at least one language",
                        Languages.Location, Project);
                  end if;

               else
                  --  Look through all the languages specified in attribute
                  --  Languages.

                  while Current /= Nil_String loop
                     Element := Shared.String_Elements.Table (Current);

                     Add_Language
                       (Get_Lower_Name_Id (Get_Name_String (Element.Value)),
                        Display_Name => Element.Value);

                     Current := Element.Next;
                  end loop;
               end if;
            end;
         end if;
   end Check_Programming_Languages;

   -------------------------------
   -- Check_Stand_Alone_Library --
   -------------------------------

   procedure Check_Stand_Alone_Library
     (Project : Project_Id;
      Data    : in out Tree_Processing_Data)
   is
      Shared : constant Shared_Project_Tree_Data_Access := Data.Tree.Shared;

      Lib_Name            : constant GPR.Variable_Value :=
                              GPR.Util.Value_Of
                               (Snames.Name_Library_Name,
                                Project.Decl.Attributes,
                                Shared);

      Lib_Standalone      : constant GPR.Variable_Value :=
                              GPR.Util.Value_Of
                                (Snames.Name_Library_Standalone,
                                 Project.Decl.Attributes,
                                 Shared);

      Lib_Auto_Init       : constant GPR.Variable_Value :=
                              GPR.Util.Value_Of
                                (Snames.Name_Library_Auto_Init,
                                 Project.Decl.Attributes,
                                 Shared);

      Lib_Src_Dir         : constant GPR.Variable_Value :=
                              GPR.Util.Value_Of
                                (Snames.Name_Library_Src_Dir,
                                 Project.Decl.Attributes,
                                 Shared);

      Lib_Symbol_File     : constant GPR.Variable_Value :=
                              GPR.Util.Value_Of
                                (Snames.Name_Library_Symbol_File,
                                 Project.Decl.Attributes,
                                 Shared);

      Lib_Symbol_Policy   : constant GPR.Variable_Value :=
                              GPR.Util.Value_Of
                                (Snames.Name_Library_Symbol_Policy,
                                 Project.Decl.Attributes,
                                 Shared);

      Auto_Init_Supported : constant Boolean :=
                              Project.Config.Auto_Init_Supported;

   begin
      --  It is a stand-alone library project file if there is at least one
      --  declared or inherited interface.

      if Project.Lib_Interface_ALIs = Nil_String
        and then Project.Other_Interfaces = Nil_String
      then
         if not Lib_Standalone.Default
           and then To_Lower (Get_Name_String (Lib_Standalone.Value)) /= "no"
         then
            Error_Msg
              (Data.Flags,
               "Library_Standalone valid only if library has interfaces",
               Lib_Standalone.Location, Project);
         end if;

      else
         if Project.Standalone_Library = No then
            Project.Standalone_Library := Standard;
         end if;

         --  The name of a stand-alone library needs to have the syntax of an
         --  Ada identifier.

         declare
            Name : constant String := Get_Name_String (Project.Library_Name);
            OK   : Boolean         := Is_Letter (Name (Name'First));

            Underline : Boolean := False;

         begin
            for J in Name'First + 1 .. Name'Last loop
               exit when not OK;

               if Is_Alphanumeric (Name (J)) then
                  Underline := False;

               elsif Name (J) = '_' then
                  if Underline then
                     OK := False;
                  else
                     Underline := True;
                  end if;

               else
                  OK := False;
               end if;
            end loop;

            OK := OK and not Underline;

            if not OK then
               Error_Msg
                 (Data.Flags,
                  "Incorrect library name for a Stand-Alone Library",
                  Lib_Name.Location, Project);
               return;
            end if;
         end;

         if Lib_Standalone.Default then
            Project.Standalone_Library := Standard;

         else
            Get_Name_String (Lib_Standalone.Value);
            Set_Casing (All_Lower_Case);

            if Name_Buffer (1 .. Name_Len) = "standard" then
               Project.Standalone_Library := Standard;

            elsif Name_Buffer (1 .. Name_Len) = "encapsulated" then
               Project.Standalone_Library := Encapsulated;

            elsif Name_Buffer (1 .. Name_Len) = "no" then
               Project.Standalone_Library := No;
               Error_Msg
                 (Data.Flags,
                  "wrong value for Library_Standalone when Library_Interface"
                  & " defined",
                  Lib_Standalone.Location, Project);

            else
               Error_Msg
                 (Data.Flags,
                  "invalid value for attribute Library_Standalone",
                  Lib_Standalone.Location, Project);
            end if;
         end if;

         --  Check value of attribute Library_Auto_Init and set Lib_Auto_Init
         --  accordingly.

         if Lib_Auto_Init.Default then

            --  If no attribute Library_Auto_Init is declared, then set auto
            --  init only if it is supported.

            Project.Lib_Auto_Init := Auto_Init_Supported;

         else
            Get_Name_String (Lib_Auto_Init.Value);
            Set_Casing (All_Lower_Case);

            if Name_Buffer (1 .. Name_Len) = "false" then
               Project.Lib_Auto_Init := False;

            elsif Name_Buffer (1 .. Name_Len) = "true" then
               if Auto_Init_Supported then
                  Project.Lib_Auto_Init := True;

               else
                  --  Library_Auto_Init cannot be "true" if auto init is not
                  --  supported.

                  Error_Msg
                    (Data.Flags,
                     "library auto init not supported on this platform",
                     Lib_Auto_Init.Location, Project);
               end if;

            else
               Error_Msg
                 (Data.Flags,
                  "invalid value for attribute Library_Auto_Init",
                  Lib_Auto_Init.Location, Project);
            end if;
         end if;

         --  If attribute Library_Src_Dir is defined and not the empty string,
         --  check if the directory exist and is not the object directory or
         --  one of the source directories. This is the directory where copies
         --  of the interface sources will be copied. Note that this directory
         --  may be the library directory.

         if Lib_Src_Dir.Value /= Empty_String then
            declare
               Dir_Id     : constant File_Name_Type :=
                              File_Name_Type (Lib_Src_Dir.Value);
               Dir_Exists : Boolean;

            begin
               Locate_Directory
                 (Project,
                  Dir_Id,
                  Path             => Project.Library_Src_Dir,
                  Dir_Exists       => Dir_Exists,
                  Data             => Data,
                  Must_Exist       => False,
                  Create           => "library source copy",
                  Location         => Lib_Src_Dir.Location,
                  Externally_Built => Project.Externally_Built);

               --  If directory does not exist, report an error

               if not Dir_Exists then
                  if Opt.Directories_Must_Exist_In_Projects then
                     --  Get the absolute name of the library directory that
                     --  does not exist, to report an error.

                     Error_Msg_File_1 :=
                       File_Name_Type (Project.Library_Src_Dir.Display_Name);
                     Error_Or_Warning
                       (Data.Flags, Data.Flags.Require_Obj_Dirs,
                        "Directory { does not exist",
                        Lib_Src_Dir.Location, Project);
                  end if;

                  --  Report error if it is the same as the object directory

               elsif Project.Library_Src_Dir = Project.Object_Directory then
                  Error_Msg
                    (Data.Flags,
                     "directory to copy interfaces cannot be the object"
                     & " directory",
                     Lib_Src_Dir.Location, Project);
                  Project.Library_Src_Dir := No_Path_Information;

               else
                  declare
                     Src_Dirs : String_List_Id;
                     Src_Dir  : String_Element;
                     Pid      : Project_List;

                  begin
                     --  Interface copy directory cannot be one of the source
                     --  directory of the current project.

                     Src_Dirs := Project.Source_Dirs;
                     while Src_Dirs /= Nil_String loop
                        Src_Dir := Shared.String_Elements.Table (Src_Dirs);

                        --  Report error if it is one of the source directories

                        if Project.Library_Src_Dir.Name =
                             Path_Name_Type (Src_Dir.Value)
                        then
                           Error_Msg
                             (Data.Flags,
                              "directory to copy interfaces cannot be one of"
                              & " the source directories",
                              Lib_Src_Dir.Location, Project);
                           Project.Library_Src_Dir := No_Path_Information;
                           exit;
                        end if;

                        Src_Dirs := Src_Dir.Next;
                     end loop;

                     if Project.Library_Src_Dir /= No_Path_Information then

                        --  It cannot be a source directory of any other
                        --  project either.

                        Pid := Data.Tree.Projects;
                        Project_Loop : loop
                           exit Project_Loop when Pid = null;

                           Src_Dirs := Pid.Project.Source_Dirs;
                           Dir_Loop : while Src_Dirs /= Nil_String loop
                              Src_Dir :=
                                Shared.String_Elements.Table (Src_Dirs);

                              --  Report error if it is one of the source
                              --  directories.

                              if Project.Library_Src_Dir.Name =
                                Path_Name_Type (Src_Dir.Value)
                              then
                                 Error_Msg_File_1 :=
                                   File_Name_Type (Src_Dir.Value);
                                 Error_Msg_Name_1 := Pid.Project.Name;
                                 Error_Msg
                                   (Data.Flags,
                                    "directory to copy interfaces cannot be"
                                    & " the same as source directory { of"
                                    & " project %%",
                                    Lib_Src_Dir.Location, Project);
                                 Project.Library_Src_Dir :=
                                   No_Path_Information;
                                 exit Project_Loop;
                              end if;

                              Src_Dirs := Src_Dir.Next;
                           end loop Dir_Loop;

                           Pid := Pid.Next;
                        end loop Project_Loop;
                     end if;
                  end;

                  --  In high verbosity, if there is a valid Library_Src_Dir,
                  --  display its path name.

                  if Project.Library_Src_Dir /= No_Path_Information
                    and then Current_Verbosity = High
                  then
                     Write_Attr
                       ("Directory to copy interfaces",
                        Get_Name_String (Project.Library_Src_Dir.Name));
                  end if;
               end if;
            end;
         end if;

         --  Check the symbol related attributes

         --  First, the symbol policy

         if Lib_Symbol_Policy.Default then
            Project.Symbol_Data.Symbol_Policy := Restricted;

         else
            declare
               Value : constant String :=
                         To_Lower (Get_Name_String (Lib_Symbol_Policy.Value));
            begin
               --  Symbol policy must have one of a limited number of values

               if Value = "unrestricted" then
                  Project.Symbol_Data.Symbol_Policy := Unrestricted;

               elsif Value = "restricted" then
                  Project.Symbol_Data.Symbol_Policy := Restricted;

               else
                  Error_Msg
                    (Data.Flags,
                     "illegal value for Library_Symbol_Policy",
                     Lib_Symbol_Policy.Location, Project);
               end if;
            end;
         end if;

         if not Lib_Symbol_File.Default then
            --  Library_Symbol_File is defined, check file exists

            Project.Symbol_Data.Symbol_File :=
              Path_Name_Type (Lib_Symbol_File.Value);

            Get_Name_String (Lib_Symbol_File.Value);

            if Name_Len = 0 then
               Error_Msg
                 (Data.Flags,
                  "symbol file name cannot be an empty string",
                  Lib_Symbol_File.Location, Project);

            else
               if not Is_Absolute_Path (Name_Buffer (1 .. Name_Len)) then
                  Get_Name_String (Project.Directory.Display_Name);
                  Get_Name_String_And_Append (Lib_Symbol_File.Value);
                  Project.Symbol_Data.Symbol_File := Name_Find;
               end if;

               if not Is_Regular_File
                 (Get_Name_String (Project.Symbol_Data.Symbol_File))
               then
                  Error_Msg_File_1 :=
                    File_Name_Type (Lib_Symbol_File.Value);

                  Error_Msg_Warn := False;

                  Error_Msg
                    (Data.Flags,
                     "<library symbol file { does not exist",
                     Lib_Symbol_File.Location, Project);

               elsif Project.Symbol_Data.Symbol_Policy = Unrestricted then
                  --  Is_Regular_File
                  --    (Get_Name_String (Project.Symbol_Data.Symbol_File))
                  --  implicit, see "if" condition.

                  Error_Msg
                    (Data.Flags,
                     "?Library_Symbol_File attribute is ignored",
                     Lib_Symbol_File.Location, Project);

                  Error_Msg
                    (Data.Flags,
                     "?\because Library_Symbol_Policy attribute has "
                     & """unrestricted"" value",
                     Lib_Symbol_Policy.Location, Project);
               end if;
            end if;
         end if;
      end if;
   end Check_Stand_Alone_Library;

   ---------------------
   -- Check_Unit_Name --
   ---------------------

   procedure Check_Unit_Name (Name : String; Unit : out Name_Id) is
      The_Name        : constant String := To_Lower (Name);
      Real_Name       : Name_Id;
      Need_Letter     : Boolean := True;
      Last_Underscore : Boolean := False;
      OK              : Boolean := The_Name'Length > 0;
      First           : Positive;

      function Is_Reserved (Name : Name_Id) return Boolean;
      function Is_Reserved (S    : String)  return Boolean;
      --  Check that the given name is not an Ada 95 reserved word. The reason
      --  for the Ada 95 here is that we do not want to exclude the case of an
      --  Ada 95 unit called Interface (for example). In Ada 2005, such a unit
      --  name would be rejected anyway by the compiler. That means there is no
      --  requirement that the project file parser reject this.

      -----------------
      -- Is_Reserved --
      -----------------

      function Is_Reserved (S : String) return Boolean is
      begin
         return Is_Reserved (Get_Name_Id (S));
      end Is_Reserved;

      -----------------
      -- Is_Reserved --
      -----------------

      function Is_Reserved (Name : Name_Id) return Boolean is
      begin
         if Name in Reserved_Ada_95 then
            Unit := No_Name;
            Debug_Output ("project reserved word: ", Name);
            return True;

         else
            return False;
         end if;
      end Is_Reserved;

   --  Start of processing for Check_Unit_Name

   begin
      Name_Len := The_Name'Length;
      Name_Buffer (1 .. Name_Len) := The_Name;

      Real_Name := Name_Find;

      if Is_Reserved (Real_Name) then
         return;
      end if;

      First := The_Name'First;

      for Index in The_Name'Range loop
         if Need_Letter then
            --  We need a letter (at the beginning, and following a dot),
            --  but we don't have one.

            if Is_Letter (The_Name (Index)) then
               Need_Letter := False;

            else
               OK := False;

               if Current_Verbosity = High then
                  Debug_Indent;
                  Write_Str (Index'Img);
                  Write_Str (": '");
                  Write_Char (The_Name (Index));
                  Write_Line ("' is not a letter.");
               end if;

               exit;
            end if;

         elsif Last_Underscore
           and then (The_Name (Index) = '_' or else The_Name (Index) = '.')
         then
            --  Two underscores are illegal, and a dot cannot follow
            --  an underscore.

            OK := False;

            if Current_Verbosity = High then
               Debug_Indent;
               Write_Str (Index'Img);
               Write_Str (": '");
               Write_Char (The_Name (Index));
               Write_Line ("' is illegal here.");
            end if;

            exit;

         elsif The_Name (Index) = '.' then
            --  First, check if the name before the dot is not a reserved word

            if Is_Reserved (The_Name (First .. Index - 1)) then
               return;
            end if;

            First := Index + 1;

            --  We need a letter after a dot

            Need_Letter := True;

         elsif The_Name (Index) = '_' then
            Last_Underscore := True;

         else
            --  We need an letter or a digit

            Last_Underscore := False;

            if not Is_Alphanumeric (The_Name (Index)) then
               OK := False;

               if Current_Verbosity = High then
                  Debug_Indent;
                  Write_Str (Index'Img);
                  Write_Str (": '");
                  Write_Char (The_Name (Index));
                  Write_Line ("' is not alphanumeric.");
               end if;

               exit;
            end if;
         end if;
      end loop;

      --  Cannot end with an underscore or a dot

      OK := OK and then not Need_Letter and then not Last_Underscore;

      if OK then
         if First /= Name'First
           and then Is_Reserved (The_Name (First .. The_Name'Last))
         then
            return;
         end if;

         Unit := Real_Name;

      else
         --  Signal a problem with No_Name

         Unit := No_Name;
      end if;
   end Check_Unit_Name;

   ----------------------------
   -- Compute_Directory_Last --
   ----------------------------

   function Compute_Directory_Last (Dir : String) return Natural is
   begin
      if Dir'Length > 1
        and then Is_Directory_Separator (Dir (Dir'Last - 1))
      then
         return Dir'Last - 1;
      else
         return Dir'Last;
      end if;
   end Compute_Directory_Last;

   --------------------------
   -- Get_Object_Directory --
   --------------------------

   procedure Get_Object_Directory
     (Project    : Project_Id;
      Data       : in out Tree_Processing_Data;
      No_Sources : Boolean := False)
   is
      Shared : constant Shared_Project_Tree_Data_Access := Data.Tree.Shared;

      Object_Dir  : constant Variable_Value :=
                      Util.Value_Of
                        (Name_Object_Dir, Project.Decl.Attributes, Shared);

      Dir_Exists : Boolean;

   begin
      --  Set the object directory to its default which may be nil, if there
      --  is no sources in the project.

      if No_Sources then
         Project.Object_Directory := No_Path_Information;
      else
         Project.Object_Directory := Project.Directory;
      end if;

      --  Check the object directory

      if Object_Dir.Value not in No_Name | Empty_String then
         Get_Name_String (Object_Dir.Value);

         if Name_Len = 0 then
            Error_Msg
              (Data.Flags,
               "Object_Dir cannot be empty",
               Object_Dir.Location, Project);

         elsif Create_Dirs /= Never_Create_Dirs
           and then No_Sources
           and then Project.Extends = No_Project
         then
            --  Do not create an object directory for a non extending project
            --  with no sources.

            Locate_Directory
              (Project,
               File_Name_Type (Object_Dir.Value),
               Path             => Project.Object_Directory,
               Dir_Exists       => Dir_Exists,
               Data             => Data,
               Location         => Object_Dir.Location,
               Must_Exist       => False,
               Externally_Built => Project.Externally_Built);

         else
            --  We check that the specified object directory does exist.
            --  However, even when it doesn't exist, we set it to a default
            --  value. This is for the benefit of tools that recover from
            --  errors; for example, these tools could create the non existent
            --  directory. We always return an absolute directory name though.

            Locate_Directory
              (Project,
               File_Name_Type (Object_Dir.Value),
               Path             => Project.Object_Directory,
               Create           => "object",
               Dir_Exists       => Dir_Exists,
               Data             => Data,
               Location         => Object_Dir.Location,
               Must_Exist       => False,
               Externally_Built => Project.Externally_Built);

            if not Dir_Exists
              and then not Project.Externally_Built
              and then Project.Qualifier /= Abstract_Project
            then
               if Opt.Directories_Must_Exist_In_Projects then

                  --  The object directory does not exist, report an error if
                  --  the project is not externally built.

                  Error_Msg_File_1 :=
                    File_Name_Type (Object_Dir.Value);
                  Error_Or_Warning
                    (Data.Flags, Data.Flags.Require_Obj_Dirs,
                     "object directory { not found",
                     Object_Dir.Location, Project);
               end if;
            end if;
         end if;

      elsif not No_Sources
        and then (Subdirs /= null or else Build_Tree_Dir /= null)
      then
         Name_Len := 1;
         Name_Buffer (1) := '.';
         Locate_Directory
           (Project,
            Name_Find,
            Path             => Project.Object_Directory,
            Create           => "object",
            Dir_Exists       => Dir_Exists,
            Data             => Data,
            Location         => Object_Dir.Location,
            Externally_Built => Project.Externally_Built);
      end if;

      if Current_Verbosity = High then
         if Project.Object_Directory = No_Path_Information then
            Debug_Output ("no object directory");
         else
            Write_Attr
              ("Object directory",
               Get_Name_String (Project.Object_Directory.Display_Name));
         end if;
      end if;
   end Get_Object_Directory;

   ---------------------
   -- Get_Directories --
   ---------------------

   procedure Get_Directories
     (Project    : Project_Id;
      Data       : in out Tree_Processing_Data;
      No_Sources : out Boolean)
   is
      Shared : constant Shared_Project_Tree_Data_Access := Data.Tree.Shared;

      Exec_Dir : constant Variable_Value :=
                   Util.Value_Of
                     (Name_Exec_Dir, Project.Decl.Attributes, Shared);

      Source_Dirs : constant Variable_Value :=
                      Util.Value_Of
                        (Name_Source_Dirs, Project.Decl.Attributes, Shared);

      Ignore_Source_Sub_Dirs : constant Variable_Value :=
                                 Util.Value_Of
                                   (Name_Ignore_Source_Sub_Dirs,
                                    Project.Decl.Attributes,
                                    Shared);

      Excluded_Source_Dirs : constant Variable_Value :=
                              Util.Value_Of
                                (Name_Excluded_Source_Dirs,
                                 Project.Decl.Attributes,
                                 Shared);

      Source_Files : constant Variable_Value :=
                      Util.Value_Of
                        (Name_Source_Files,
                         Project.Decl.Attributes, Shared);

      Last_Source_Dir   : String_List_Id    := Nil_String;
      Last_Src_Dir_Rank : Number_List_Index := No_Number_List;

      Languages : constant Variable_Value :=
                      GPR.Util.Value_Of
                        (Name_Languages, Project.Decl.Attributes, Shared);

      procedure Add_To_Or_Remove_From_Source_Dirs
        (Path : Path_Information; Rank : Natural; Remove : Boolean);
      --  When Remove = False, Adds the directory Path_Id to the list of
      --  source_dirs if not already in the list. When Remove = True,
      --  removes directory Path_Id if in the list.

      procedure Add_To_Source_Dirs (Path : Path_Information; Rank : Natural);
      --  Adds the directory Path_Id to the list of source_dirs if not already
      --  in the list.

      procedure Remove_From_Source_Dirs
        (Path : Path_Information; Rank : Natural);
      --  Removes directory Path_Id if in the list.

      procedure Find_Source_Dirs
        (Patterns  : String_List_Id;
         Ignore    : String_List_Id;
         Callback  : not null access procedure
           (Path          : Path_Information;
            Pattern_Index : Natural) := Add_To_Source_Dirs'Access);

      ----------------------
      -- Find_Source_Dirs --
      ----------------------

      procedure Find_Source_Dirs
        (Patterns  : String_List_Id;
         Ignore    : String_List_Id;
         Callback  : not null access procedure
           (Path          : Path_Information;
            Pattern_Index : Natural) := Add_To_Source_Dirs'Access) is
      begin
         Expand_Subdirectory_Pattern
           (Project       => Project,
            Data          => Data,
            Patterns      => Patterns,
            Ignore        => Ignore,
            Search_For    => Search_Source_Directories,
            Resolve_Links => Opt.Follow_Links_For_Dirs,
            Callback      => Callback);
      end Find_Source_Dirs;

      ---------------------------------------
      -- Add_To_Or_Remove_From_Source_Dirs --
      ---------------------------------------

      procedure Add_To_Or_Remove_From_Source_Dirs
        (Path   : Path_Information;
         Rank   : Natural;
         Remove : Boolean)
      is
         List      : String_List_Id;
         Prev      : String_List_Id;
         Rank_List : Number_List_Index;
         Prev_Rank : Number_List_Index;
         Element   : String_Element;

      begin
         Prev      := Nil_String;
         Prev_Rank := No_Number_List;
         List      := Project.Source_Dirs;
         Rank_List := Project.Source_Dir_Ranks;
         while List /= Nil_String loop
            Element := Shared.String_Elements.Table (List);
            exit when Element.Value = Name_Id (Path.Name);
            Prev := List;
            List := Element.Next;
            Prev_Rank := Rank_List;
            Rank_List := Shared.Number_Lists.Table (Prev_Rank).Next;
         end loop;

         --  The directory is in the list if List is not Nil_String

         if not Remove and then List = Nil_String then
            Debug_Output ("adding source dir=", Name_Id (Path.Display_Name));

            String_Element_Table.Increment_Last (Shared.String_Elements);
            Element :=
              (Value         => Name_Id (Path.Name),
               Index         => 0,
               Display_Value => Name_Id (Path.Display_Name),
               Location      => No_Location,
               Next          => Nil_String);

            Number_List_Table.Increment_Last (Shared.Number_Lists);

            if Last_Source_Dir = Nil_String then

               --  This is the first source directory

               Project.Source_Dirs :=
                 String_Element_Table.Last (Shared.String_Elements);
               Project.Source_Dir_Ranks :=
                 Number_List_Table.Last (Shared.Number_Lists);

            else
               --  We already have source directories, link the previous
               --  last to the new one.

               Shared.String_Elements.Table (Last_Source_Dir).Next :=
                 String_Element_Table.Last (Shared.String_Elements);
               Shared.Number_Lists.Table (Last_Src_Dir_Rank).Next :=
                 Number_List_Table.Last (Shared.Number_Lists);
            end if;

            --  And register this source directory as the new last

            Last_Source_Dir :=
              String_Element_Table.Last (Shared.String_Elements);
            Shared.String_Elements.Table (Last_Source_Dir) := Element;
            Last_Src_Dir_Rank :=
              Number_List_Table.Last (Shared.Number_Lists);
            Shared.Number_Lists.Table (Last_Src_Dir_Rank) :=
              (Number => Rank, Next => No_Number_List);

         elsif Remove and then List /= Nil_String then
            --  Remove source dir if present

            if Prev = Nil_String then
               Project.Source_Dirs := Shared.String_Elements.Table (List).Next;
               Project.Source_Dir_Ranks :=
                 Shared.Number_Lists.Table (Rank_List).Next;

            else
               Shared.String_Elements.Table (Prev).Next :=
                 Shared.String_Elements.Table (List).Next;
               Shared.Number_Lists.Table (Prev_Rank).Next :=
                 Shared.Number_Lists.Table (Rank_List).Next;
            end if;
         end if;
      end Add_To_Or_Remove_From_Source_Dirs;

      ------------------------
      -- Add_To_Source_Dirs --
      ------------------------

      procedure Add_To_Source_Dirs
        (Path : Path_Information; Rank : Natural) is
      begin
         Add_To_Or_Remove_From_Source_Dirs (Path, Rank, Remove => False);
      end Add_To_Source_Dirs;

      -----------------------------
      -- Remove_From_Source_Dirs --
      -----------------------------

      procedure Remove_From_Source_Dirs
        (Path : Path_Information; Rank : Natural) is
      begin
         Add_To_Or_Remove_From_Source_Dirs (Path, Rank, Remove => True);
      end Remove_From_Source_Dirs;

      --  Local declarations

      Dir_Exists : Boolean;

   --  Start of processing for Get_Directories

   begin
      No_Sources :=
        Project.Qualifier = Abstract_Project
        or else (((not Source_Files.Default
                   and then Source_Files.Values = Nil_String)
                  or else
                    (not Source_Dirs.Default
                     and then Source_Dirs.Values  = Nil_String)
                  or else
                    (not Languages.Default
                     and then Languages.Values    = Nil_String))
                 and then Project.Extends = No_Project);

      Debug_Output ("starting to look for directories");

      Get_Object_Directory (Project, Data, No_Sources);

      --  Check the exec directory

      --  We set the object directory to its default

      Project.Exec_Directory := Project.Object_Directory;

      if Exec_Dir.Value not in Empty_String | No_Name then
         Get_Name_String (Exec_Dir.Value);

         if Name_Len = 0 then
            Error_Msg
              (Data.Flags,
               "Exec_Dir cannot be empty",
               Exec_Dir.Location, Project);

         elsif Create_Dirs /= Never_Create_Dirs
           and then No_Sources
           and then Project.Extends = No_Project
         then
            --  Do not create an exec directory for a non extending project
            --  with no sources.

            Locate_Directory
              (Project,
               File_Name_Type (Exec_Dir.Value),
               Path             => Project.Exec_Directory,
               Dir_Exists       => Dir_Exists,
               Data             => Data,
               Must_Exist       => False,
               Location         => Exec_Dir.Location,
               Externally_Built => Project.Externally_Built);

         else
            --  We check that the specified exec directory does exist

            Locate_Directory
              (Project,
               File_Name_Type (Exec_Dir.Value),
               Path             => Project.Exec_Directory,
               Dir_Exists       => Dir_Exists,
               Data             => Data,
               Create           => "exec",
               Must_Exist       => False,
               Location         => Exec_Dir.Location,
               Externally_Built => Project.Externally_Built);

            if not Dir_Exists
              and then not Project.Externally_Built
              and then not (Project.Qualifier = Abstract_Project)
            then
               if Opt.Directories_Must_Exist_In_Projects then
                  Error_Msg_File_1 := File_Name_Type (Exec_Dir.Value);
                  Error_Or_Warning
                    (Data.Flags, Data.Flags.Require_Obj_Dirs,
                     "exec directory { not found", Project.Location, Project);

               else
                  Project.Exec_Directory := No_Path_Information;
               end if;
            end if;
         end if;
      end if;

      if Current_Verbosity = High then
         if Project.Exec_Directory = No_Path_Information then
            Debug_Output ("no exec directory");
         else
            Debug_Output
              ("exec directory: ",
               Name_Id (Project.Exec_Directory.Display_Name));
         end if;
      end if;

      --  Look for the source directories

      Debug_Output ("starting to look for source directories");

      pragma Assert (Source_Dirs.Kind = List, "Source_Dirs is not a list");

      if not Source_Files.Default and then Source_Files.Values = Nil_String
      then
         Project.Source_Dirs := Nil_String;

         if Project.Qualifier = Standard then
            Error_Msg
              (Data.Flags,
               "a standard project must have sources",
               Source_Files.Location, Project);
         end if;

         --  No source dirs: nothing further to do

         return;
      end if;

      --  If we were provided src-subdirs, add <object dir>/<src-subdirs> in
      --  front of the source directories so that files found in this directory
      --  will override original source files.

      if Src_Subdirs /= null
        and then Project.Qualifier /= Abstract_Project
        and then not No_Sources
      then
         declare
            function Try_Src_Subdir (Prefix : Name_Id) return Boolean;
            --  Try to add source subdirectory in object directory Obj_Dir with
            --  Prefix or not if Prefix is No_Name. Returns True on success.

            function Get_Src_Subdir (Prefix : Name_Id) return String is
              ((if Prefix = No_Name then ""
                else Get_Name_String (Prefix) & '-')
               & Src_Subdirs.all & Directory_Separator);
            --  Returns --src-subdirs parameter either with project name prefix
            --  or not if PRefix is No_Name.

            --------------------
            -- Try_Src_Subdir --
            --------------------

            function Try_Src_Subdir (Prefix : Name_Id) return Boolean is
               Src_Subdir : constant String := Get_Src_Subdir (Prefix);
               Name       : Path_Name_Type;
               N          : String :=
                 Get_Name_String (Project.Object_Directory.Name) & Src_Subdir;
            begin
               if Is_Directory (N) then
                  Canonical_Case_File_Name (N);
                  Name := Get_Path_Name_Id (N);

                  --  Set Rank to 0 so that duplicate units are silently
                  --  accepted.

                  Add_To_Source_Dirs
                    (Path => (Name => Name,
                              Display_Name => Get_Path_Name_Id
                                (Get_Name_String
                                   (Project.Object_Directory.Display_Name)
                                 & Src_Subdir)),
                     Rank => 0);

                  return True;
               end if;

               return False;
            end Try_Src_Subdir;

         begin
            if Try_Src_Subdir (Project.Name) or else Try_Src_Subdir (No_Name)
            then
               null;
            end if;
         end;
      end if;

      if Source_Dirs.Default then
         --  No Source_Dirs specified: the single source directory is the one
         --  containing the project file.

         Add_To_Source_Dirs (Path => Project.Directory, Rank => 1);

      else
         Find_Source_Dirs (Source_Dirs.Values, Ignore_Source_Sub_Dirs.Values);

         if Project.Source_Dirs = Nil_String
           and then Project.Qualifier = Standard
         then
            Error_Msg
              (Data.Flags,
               "a standard project must have source directories",
               Source_Dirs.Location, Project);
         end if;
      end if;

      if not Excluded_Source_Dirs.Default
        and then Excluded_Source_Dirs.Values /= Nil_String
      then
         Find_Source_Dirs
           (Excluded_Source_Dirs.Values, Nil_String,
            Remove_From_Source_Dirs'Access);
      end if;

      Debug_Output ("putting source directories in canonical cases");

      declare
         Current : String_List_Id := Project.Source_Dirs;
         Element : String_Element;

      begin
         while Current /= Nil_String loop
            Element := Shared.String_Elements.Table (Current);
            if Element.Value /= No_Name then
               Element.Value :=
                 Name_Id (Canonical_Case_File_Name (Element.Value));
               Shared.String_Elements.Table (Current) := Element;
            end if;

            Current := Element.Next;
         end loop;
      end;
   end Get_Directories;

   ---------------
   -- Get_Mains --
   ---------------

   procedure Get_Mains
     (Project : Project_Id;
      Data    : in out Tree_Processing_Data)
   is
      Shared : constant Shared_Project_Tree_Data_Access := Data.Tree.Shared;

      Mains : constant Variable_Value :=
               GPR.Util.Value_Of
                 (Name_Main, Project.Decl.Attributes, Shared);
      List  : String_List_Id;
      Elem  : String_Element;

   begin
      Project.Mains := Mains.Values;

      --  If no Mains were specified, and if we are an extending project,
      --  inherit the Mains from the project we are extending.

      if Mains.Default then
         if not Project.Library and then Project.Extends /= No_Project then
            Project.Mains := Project.Extends.Mains;
         end if;

      --  In a library project file, Main cannot be specified

      elsif Project.Library then
         Error_Msg
           (Data.Flags,
            "a library project file cannot have Main specified",
            Mains.Location, Project);

      else
         List := Mains.Values;
         while List /= Nil_String loop
            Elem := Shared.String_Elements.Table (List);

            if Elem.Value = Empty_String then
               Error_Msg
                 (Data.Flags,
                  "?a main cannot have an empty name",
                  Elem.Location, Project);
               exit;
            end if;

            List := Elem.Next;
         end loop;
      end if;
   end Get_Mains;

   ---------------------------
   -- Get_Sources_From_File --
   ---------------------------

   procedure Get_Sources_From_File
     (Path     : String;
      Location : Source_Ptr;
      Project  : in out Project_Processing_Data;
      Data     : in out Tree_Processing_Data)
   is
      File        : GPR.Util.Text_File;
      Line        : String (1 .. 250);
      Last        : Natural;
      Source_Name : File_Name_Type;
      Name_Loc    : Name_Location;

   begin
      if Current_Verbosity = High then
         Debug_Output ("opening """ & Path & '"');
      end if;

      --  Open the file

      GPR.Util.Open (File, Path);

      if not GPR.Util.Is_Valid (File) then
         Error_Msg
           (Data.Flags, "file does not exist", Location, Project.Project);

      else
         --  Read the lines one by one

         while not GPR.Util.End_Of_File (File) loop
            GPR.Util.Get_Line (File, Line, Last);

            --  A non empty, non comment line should contain a file name

            if Last /= 0 and then (Last = 1 or else Line (1 .. 2) /= "--") then
               Name_Len := Last;
               Name_Buffer (1 .. Name_Len) := Line (1 .. Last);
               Canonical_Case_File_Name (Name_Buffer (1 .. Name_Len));
               Source_Name := Name_Find;

               --  Check that there is no directory information

               for J in 1 .. Last loop
                  if Is_Directory_Separator (Line (J)) then
                     Error_Msg_File_1 := Source_Name;
                     Error_Msg
                       (Data.Flags,
                        "file name cannot include directory information ({)",
                        Location, Project.Project);
                     exit;
                  end if;
               end loop;

               Name_Loc := Source_Names_Htable.Get
                 (Project.Source_Names, Source_Name);

               if Name_Loc = No_Name_Location then
                  Name_Loc :=
                    (Name     => Source_Name,
                     Location => Location,
                     Source   => No_Source,
                     Listed   => True,
                     Found    => False);

               else
                  Name_Loc.Listed := True;
               end if;

               Source_Names_Htable.Set
                 (Project.Source_Names, Source_Name, Name_Loc);
            end if;
         end loop;

         GPR.Util.Close (File);

      end if;
   end Get_Sources_From_File;

   ------------------
   -- No_Space_Img --
   ------------------

   function No_Space_Img (N : Natural) return String is
      Image : constant String := N'Img;
   begin
      return Image (2 .. Image'Last);
   end No_Space_Img;

   -----------------------
   -- Compute_Unit_Name --
   -----------------------

   procedure Compute_Unit_Name
     (File_Name : File_Name_Type;
      Naming    : Lang_Naming_Data;
      Kind      : out Source_Kind;
      Unit      : out Name_Id;
      Project   : Project_Processing_Data)
   is
      Filename : constant String  := Get_Name_String (File_Name);
      Last     : Integer          := Filename'Last;
      Sep_Len  : Integer;
      Body_Len : Integer;
      Spec_Len : Integer;

      Unit_Except : Unit_Exception;
      Masked      : Boolean  := False;

   begin
      Unit := No_Name;
      Kind := Spec;

      if Naming.Separate_Suffix = No_File
        or else Naming.Body_Suffix = No_File
        or else Naming.Spec_Suffix = No_File
      then
         return;
      end if;

      if Naming.Dot_Replacement = No_File then
         Debug_Output ("no dot_replacement specified");
         return;
      end if;

      Sep_Len  := Integer (Length_Of_Name (Naming.Separate_Suffix));
      Spec_Len := Integer (Length_Of_Name (Naming.Spec_Suffix));
      Body_Len := Integer (Length_Of_Name (Naming.Body_Suffix));

      --  Choose the longest suffix that matches. If there are several matches,
      --  give priority to specs, then bodies, then separates.

      if Naming.Separate_Suffix /= Naming.Body_Suffix
        and then Suffix_Matches (Filename, Naming.Separate_Suffix)
      then
         Last := Filename'Last - Sep_Len;
         Kind := Sep;
      end if;

      if Filename'Last - Body_Len <= Last
        and then Suffix_Matches (Filename, Naming.Body_Suffix)
      then
         Last := Natural'Min (Last, Filename'Last - Body_Len);
         Kind := Impl;
      end if;

      if Filename'Last - Spec_Len <= Last
        and then Suffix_Matches (Filename, Naming.Spec_Suffix)
      then
         Last := Natural'Min (Last, Filename'Last - Spec_Len);
         Kind := Spec;
      end if;

      if Last = Filename'Last then
         Debug_Output ("no matching suffix");
         return;
      end if;

      --  Check that the casing matches.
      --  The debug flag -du deactivates this.

      if not Debug.Debug_Flag_U and then File_Names_Case_Sensitive then
         case Naming.Casing is
            when All_Lower_Case =>
               for J in Filename'First .. Last loop
                  if Is_Letter (Filename (J))
                    and then not Is_Lower (Filename (J))
                  then
                     Debug_Output ("invalid casing");
                     return;
                  end if;
               end loop;

            when All_Upper_Case =>
               for J in Filename'First .. Last loop
                  if Is_Letter (Filename (J))
                    and then not Is_Upper (Filename (J))
                  then
                     Debug_Output ("invalid casing");
                     return;
                  end if;
               end loop;

            when Mixed_Case | Unknown =>
               null;
         end case;
      end if;

      --  If Dot_Replacement is not a single dot, then there should not
      --  be any dot in the name.

      declare
         Dot_Repl : constant String :=
                      Get_Name_String (Naming.Dot_Replacement);

      begin
         if Dot_Repl /= "." then
            for Index in Filename'First .. Last loop
               if Filename (Index) = '.' then
                  Debug_Output ("invalid name, contains dot");
                  return;
               end if;
            end loop;

            Replace_Into_Name_Buffer
              (Filename (Filename'First .. Last), Dot_Repl, '.');

         else
            Name_Len := Last - Filename'First + 1;
            Name_Buffer (1 .. Name_Len) := Filename (Filename'First .. Last);
            Fixed.Translate
              (Source  => Name_Buffer (1 .. Name_Len),
               Mapping => Lower_Case_Map);
         end if;
      end;

      --  In the standard GNAT naming scheme, check for special cases: children
      --  or separates of A, G, I or S, and run time sources.

      if Is_Standard_GNAT_Naming (Naming) and then Name_Len >= 3 then
         declare
            S1 : constant Character := Name_Buffer (1);
            S2 : constant Character := Name_Buffer (2);
            S3 : constant Character := Name_Buffer (3);

         begin
            if S1 = 'a' or else S1 = 'g' or else S1 = 'i' or else S1 = 's' then

               --  Children or separates of packages A, G, I or S. These names
               --  are x__ ... or x~... (where x is a, g, i, or s). Both
               --  versions (x__... and x~...) are allowed in all platforms,
               --  because it is not possible to know the platform before
               --  processing of the project files.

               if S2 = '_' and then S3 = '_' then
                  Name_Buffer (2) := '.';
                  Name_Buffer (3 .. Name_Len - 1) :=
                    Name_Buffer (4 .. Name_Len);
                  Name_Len := Name_Len - 1;

               elsif S2 = '~' then
                  Name_Buffer (2) := '.';

               elsif S2 = '.' then

                  --  If it is potentially a run time source

                  null;
               end if;
            end if;
         end;
      end if;

      --  Name_Buffer contains the name of the unit in lower-cases. Check
      --  that this is a valid unit name.
      --  The debug flag -du deactivates this.

      if not Debug.Debug_Flag_U then
         Check_Unit_Name (Name_Buffer (1 .. Name_Len), Unit);
      else
         Unit := Name_Find;
      end if;

      --  If there is a naming exception for the same unit, the file is not
      --  a source for the unit.

      if Unit /= No_Name then
         Unit_Except :=
           Unit_Exceptions_Htable.Get (Project.Unit_Exceptions, Unit);

         if Kind = Spec then
            Masked := Unit_Except.Spec /= No_File
                        and then
                      Unit_Except.Spec /= File_Name;
         else
            Masked := Unit_Except.Impl /= No_File
                        and then
                      Unit_Except.Impl /= File_Name;
         end if;

         if Masked then
            if Current_Verbosity = High then
               Debug_Indent;
               Write_Str ("   """ & Filename & """ contains the ");

               if Kind = Spec then
                  Write_Str ("spec of a unit found in """);
                  Write_Str (Get_Name_String (Unit_Except.Spec));
               else
                  Write_Str ("body of a unit found in """);
                  Write_Str (Get_Name_String (Unit_Except.Impl));
               end if;

               Write_Line (""" (ignored)");
            end if;

            Unit := No_Name;
         end if;
      end if;

      if Unit /= No_Name and then Current_Verbosity = High then
         case Kind is
            when Spec => Debug_Output ("spec of", Unit);
            when Impl => Debug_Output ("body of", Unit);
            when Sep  => Debug_Output ("sep of", Unit);
         end case;
      end if;
   end Compute_Unit_Name;

   --------------------------
   -- Check_Illegal_Suffix --
   --------------------------

   procedure Check_Illegal_Suffix
     (Project         : Project_Id;
      Suffix          : File_Name_Type;
      Dot_Replacement : File_Name_Type;
      Attribute_Name  : String;
      Location        : Source_Ptr;
      Data            : in out Tree_Processing_Data)
   is
      Suffix_Str : constant String := Get_Name_String (Suffix);

   begin
      if Suffix_Str'Length = 0 then

         --  Always valid

         return;

      elsif Index (Suffix_Str, ".") = 0 then
         Error_Msg_File_1 := Suffix;
         Error_Msg
           (Data.Flags,
            "{ is illegal for " & Attribute_Name & ": must have a dot",
            Location, Project);
         return;
      end if;

      --  Case of dot replacement is a single dot, and first character of
      --  suffix is also a dot.

      if Dot_Replacement /= No_File
        and then Get_Name_String (Dot_Replacement) = "."
        and then Suffix_Str (Suffix_Str'First) = '.'
      then
         for Index in Suffix_Str'First + 1 .. Suffix_Str'Last loop

            --  If there are multiple dots in the name

            if Suffix_Str (Index) = '.' then

               --  It is illegal to have a letter following the initial dot

               if Is_Letter (Suffix_Str (Suffix_Str'First + 1)) then
                  Error_Msg_File_1 := Suffix;
                  Error_Msg
                    (Data.Flags,
                     "{ is illegal for " & Attribute_Name
                     & ": ambiguous prefix when Dot_Replacement is a dot",
                     Location, Project);
               end if;
               return;
            end if;
         end loop;
      end if;
   end Check_Illegal_Suffix;

   ----------------------
   -- Locate_Directory --
   ----------------------

   procedure Locate_Directory
     (Project          : Project_Id;
      Name             : File_Name_Type;
      Path             : out Path_Information;
      Dir_Exists       : out Boolean;
      Data             : in out Tree_Processing_Data;
      Create           : String := "";
      Location         : Source_Ptr := No_Location;
      Must_Exist       : Boolean := True;
      Externally_Built : Boolean := False)
   is
      Parent          : constant Path_Name_Type :=
                          Project.Directory.Display_Name;
      The_Parent      : constant String := Get_Name_String (Parent);
      The_Parent_Last : constant Natural :=
                          Compute_Directory_Last (The_Parent);
      Full_Name       : File_Name_Type;
      The_Name        : File_Name_Type;

      Is_Relative     : Boolean;

   begin
      --  Check if we have a root-object dir specified, if so relocate all
      --  artefact directories to it.

      if not Externally_Built
        and then Build_Tree_Dir /= null
        and then Create /= ""
        and then not Is_Absolute_Path (Get_Name_String (Name))
      then
         Set_Name_Buffer (Build_Tree_Dir.all);

         if The_Parent_Last - The_Parent'First  + 1 < Root_Dir'Length then
            Error_Msg_File_1 := Name;
            Error_Or_Warning
              (Data.Flags, Error,
               "{ cannot relocate deeper than " & Create & " directory",
               No_Location, Project);
         end if;

         Add_Str_To_Name_Buffer
           (Relative_Path
              (The_Parent (The_Parent'First .. The_Parent_Last),
               Root_Dir.all));
         Get_Name_String_And_Append (Name);

      else
         if not Externally_Built
           and then Build_Tree_Dir /= null
           and then Create /= ""
         then
            --  Issue a warning that we cannot relocate absolute obj dir

            Error_Msg_File_1 := Name;
            Error_Or_Warning
              (Data.Flags, Warning,
               "{ cannot relocate absolute object directory",
               No_Location, Project);
         end if;

         Get_Name_String (Name);
      end if;

      --  Convert '/' to directory separator (for Windows)

      if Directory_Separator /= '/' then
         for J in 1 .. Name_Len loop
            if Name_Buffer (J) = '/' then
               Name_Buffer (J) := Directory_Separator;
            end if;
         end loop;
      end if;

      --  Add Subdirs.all if it is a directory that may be created and
      --  Subdirs is not null;

      if Create /= "" and then Subdirs /= null then
         if Name_Buffer (Name_Len) /= Directory_Separator then
            Add_Char_To_Name_Buffer (Directory_Separator);
         end if;

         Add_Str_To_Name_Buffer (Subdirs.all);
      end if;

      The_Name := Name_Find;

      if Current_Verbosity = High then
         Debug_Indent;
         Write_Str ("Locate_Directory (""");
         Write_Str (Get_Name_String (The_Name));
         Write_Str (""", in """);
         Write_Str (The_Parent);
         Write_Line (""")");
      end if;

      Path := No_Path_Information;
      Dir_Exists := False;

      if Is_Absolute_Path (Get_Name_String (The_Name)) then
         Is_Relative := False;
         Full_Name := The_Name;

      else
         Is_Relative := True;
         Set_Name_Buffer
           (The_Parent (The_Parent'First .. The_Parent_Last));
         Get_Name_String_And_Append (The_Name);
         Full_Name := Name_Find;
      end if;

      declare
         Full_Path_Name : String_Access :=
           new String'(Get_Name_String (Full_Name));
      begin
         --  We may proceed with directory creation depending on the value
         --  of Create_Dirs: if it is set to Create_All_Dirs, or if the dir
         --  is relative and Create_Dirs is set to Create_Relative_Dirs_Only.
         if (Create_Dirs = Create_All_Dirs
             or else
               (Create_Dirs = Create_Relative_Dirs_Only and then Is_Relative)
             or else Subdirs /= null)
           and then Create'Length > 0
           and then Project.Qualifier /= Abstract_Project
         then
            if not Is_Directory (Full_Path_Name.all) then
               --  If project is externally built, do not create a subdir,
               --  use the specified directory, without the subdir.

               if Externally_Built then
                  if Is_Absolute_Path (Get_Name_String (Name)) then
                     Get_Name_String (Name);

                  else
                     Set_Name_Buffer
                       (The_Parent (The_Parent'First .. The_Parent_Last));
                     Get_Name_String_And_Append (Name);
                  end if;

                  Free (Full_Path_Name);
                  Full_Path_Name := new String'(Name_Buffer (1 .. Name_Len));

               else
                  begin
                     Create_Path (Full_Path_Name.all);

                     if not GPR.Opt.Quiet_Output then
                        if Verbose_Mode then
                           Write_Str (Create);
                           Write_Str (" directory """);
                           Write_Str (Full_Path_Name.all);
                           Write_Str (""" created for project ");
                           Write_Line (Get_Name_String (Project.Display_Name));

                        else
                           Display
                             (Section  => Setup,
                              Command  => "mkdir",
                              Argument => Create & " directory for project "
                              & Get_Name_String (Project.Display_Name));
                        end if;
                     end if;

                  exception
                     when Ada.Directories.Use_Error =>
                        --  Output message with name of directory. Note that we
                        --  use the ~ insertion method here in case the name
                        --  has special characters in it.

                        Error_Msg_Strlen := Full_Path_Name'Length;
                        Error_Msg_String (1 .. Error_Msg_Strlen) :=
                          Full_Path_Name.all;
                        Error_Msg
                          (Data.Flags,
                           "could not create " & Create & " directory ~",
                           Location, Project);
                  end;
               end if;
            end if;
         end if;

         Dir_Exists := Is_Directory (Full_Path_Name.all);

         if not Must_Exist or Dir_Exists then
            declare
               Normed : constant String :=
                          Normalize_Pathname
                            (Full_Path_Name.all,
                             Directory      =>
                              The_Parent (The_Parent'First .. The_Parent_Last),
                             Resolve_Links  => False,
                             Case_Sensitive => True);

               Canonical_Path : constant String :=
                                  Normalize_Pathname
                                    (Normed,
                                     Directory      =>
                                       The_Parent
                                         (The_Parent'First .. The_Parent_Last),
                                     Resolve_Links  =>
                                        Opt.Follow_Links_For_Dirs,
                                     Case_Sensitive => False);

            begin
               Name_Len := Normed'Length;
               Name_Buffer (1 .. Name_Len) := Normed;

               --  Directories should always end with a directory separator

               if Name_Buffer (Name_Len) /= Directory_Separator then
                  Add_Char_To_Name_Buffer (Directory_Separator);
               end if;

               Path.Display_Name := Name_Find;

               Name_Len := Canonical_Path'Length;
               Name_Buffer (1 .. Name_Len) := Canonical_Path;

               if Name_Buffer (Name_Len) /= Directory_Separator then
                  Add_Char_To_Name_Buffer (Directory_Separator);
               end if;

               Path.Name := Name_Find;
            end;
         end if;

         Free (Full_Path_Name);
      end;
   end Locate_Directory;

   ---------------------------
   -- Find_Excluded_Sources --
   ---------------------------

   procedure Find_Excluded_Sources
     (Project : in out Project_Processing_Data;
      Data    : in out Tree_Processing_Data)
   is
      Shared : constant Shared_Project_Tree_Data_Access := Data.Tree.Shared;

      Current         : String_List_Id;
      Element         : String_Element;
      Location        : Source_Ptr;
      Name            : File_Name_Type;
      File            : GPR.Util.Text_File;
      Line            : String (1 .. 300);
      Last            : Natural;
      Locally_Removed : Boolean := False;

      Proj : Project_Id := Project.Project;

   begin
      --  Look for excluded sources in the current project and in all the
      --  projects that extend it.

      while Proj /= No_Project loop
         declare
            Excluded_Source_List_File : constant Variable_Value :=
              Util.Value_Of
                (Name_Excluded_Source_List_File,
                 Proj.Decl.Attributes,
                 Shared);
            Excluded_Sources          : Variable_Value := Util.Value_Of
              (Name_Excluded_Source_Files,
               Proj.Decl.Attributes,
               Shared);

         begin
            --  If Excluded_Source_Files is not declared, check
            --  Locally_Removed_Files.

            if Excluded_Sources.Default then
               Locally_Removed := True;
               Excluded_Sources :=
                 Util.Value_Of
                   (Name_Locally_Removed_Files,
                    Proj.Decl.Attributes, Shared);
            end if;

            --  If there are excluded sources, put them in the table

            if not Excluded_Sources.Default then
               if not Excluded_Source_List_File.Default then
                  if Locally_Removed then
                     Error_Msg
                       (Data.Flags,
                        "?both attributes Locally_Removed_Files and "
                        & "Excluded_Source_List_File are present",
                        Excluded_Source_List_File.Location, Proj);
                  else
                     Error_Msg
                       (Data.Flags,
                        "?both attributes Excluded_Source_Files and "
                        & "Excluded_Source_List_File are present",
                        Excluded_Source_List_File.Location, Proj);
                  end if;
               end if;

               Current := Excluded_Sources.Values;
               while Current /= Nil_String loop
                  Element := Shared.String_Elements.Table (Current);
                  Name := Canonical_Case_File_Name (Element.Value);

                  --  If the element has no location, then use the location of
                  --  Excluded_Sources to report possible errors.

                  if Element.Location = No_Location then
                     Location := Excluded_Sources.Location;
                  else
                     Location := Element.Location;
                  end if;

                  Excluded_Sources_Htable.Set
                    (Project.Excluded, Name,
                     (Name, No_File, 0, False, Location, Proj));
                  Current := Element.Next;
               end loop;

            elsif not Excluded_Source_List_File.Default then
               Location := Excluded_Source_List_File.Location;

               declare
                  Source_File_Name : constant File_Name_Type :=
                    File_Name_Type
                      (Excluded_Source_List_File.Value);
                  Source_File_Line : Natural := 0;

                  Source_File_Path_Name : constant String :=
                    Path_Name_Of
                      (Source_File_Name,
                       Proj.Directory.Name);

               begin
                  if Source_File_Path_Name'Length = 0 then
                     Error_Msg_File_1 :=
                       File_Name_Type (Excluded_Source_List_File.Value);
                     Error_Msg
                       (Data.Flags,
                        "file with excluded sources { does not exist",
                        Excluded_Source_List_File.Location, Proj);

                  else
                     --  Open the file

                     GPR.Util.Open (File, Source_File_Path_Name);

                     if not GPR.Util.Is_Valid (File) then
                        Error_Msg
                          (Data.Flags, "file does not exist", Location, Proj);
                     else
                        --  Read the lines one by one

                        while not GPR.Util.End_Of_File (File) loop
                           GPR.Util.Get_Line (File, Line, Last);
                           Source_File_Line := Source_File_Line + 1;

                           --  Non empty, non comment line should contain a
                           --  file name

                           if Last /= 0
                             and then (Last = 1 or else Line (1 .. 2) /= "--")
                           then
                              Name_Len := Last;
                              Name_Buffer (1 .. Name_Len) := Line (1 .. Last);
                              Canonical_Case_File_Name
                                (Name_Buffer (1 .. Name_Len));
                              Name := Name_Find;

                              --  Check that there is no directory information

                              for J in 1 .. Last loop
                                 if Is_Directory_Separator (Line (J)) then
                                    Error_Msg_File_1 := Name;
                                    Error_Msg
                                      (Data.Flags,
                                       "file name cannot include directory"
                                       & " information ({)",
                                       Location, Proj);
                                    exit;
                                 end if;
                              end loop;

                              Excluded_Sources_Htable.Set
                                (Project.Excluded,
                                 Name,
                                 (Name, Source_File_Name, Source_File_Line,
                                  False, Location, Proj));
                           end if;
                        end loop;

                        GPR.Util.Close (File);
                     end if;
                  end if;
               end;
            end if;
         end;

         Proj := Proj.Extended_By;
      end loop;
   end Find_Excluded_Sources;

   ------------------
   -- Find_Sources --
   ------------------

   procedure Find_Sources
     (Project : in out Project_Processing_Data;
      Data    : in out Tree_Processing_Data)
   is
      Shared : constant Shared_Project_Tree_Data_Access := Data.Tree.Shared;

      Sources : constant Variable_Value :=
                  Util.Value_Of
                    (Name_Source_Files,
                     Project.Project.Decl.Attributes,
                     Shared);

      Source_List_File : constant Variable_Value :=
                           Util.Value_Of
                             (Name_Source_List_File,
                              Project.Project.Decl.Attributes,
                              Shared);

      Name_Loc             : Name_Location;
      Has_Explicit_Sources : Boolean;

   begin
      pragma Assert (Sources.Kind = List, "Source_Files is not a list");
      pragma Assert
        (Source_List_File.Kind = Single,
         "Source_List_File is not a single string");

      Project.Source_List_File_Location := Source_List_File.Location;

      --  If the user has specified a Source_Files attribute

      if not Sources.Default then
         if not Source_List_File.Default then
            Error_Msg
              (Data.Flags,
               "?both attributes Source_Files and Source_List_File are"
               & " present",
               Source_List_File.Location, Project.Project);
         end if;

         --  Sources is a list of file names

         declare
            Current  : String_List_Id := Sources.Values;
            Element  : String_Element;
            Location : Source_Ptr;
            Name     : File_Name_Type;

         begin
            if Current = Nil_String then
               --  This project contains no source. For projects that don't
               --  extend other projects, this also means that there is no
               --  need for an object directory, if not specified.

               if Project.Project.Extends = No_Project
                 and then
                   Project.Project.Object_Directory = Project.Project.Directory
                 and then not (Project.Project.Qualifier = Aggregate_Library)
               then
                  Project.Project.Object_Directory := No_Path_Information;
               end if;
            end if;

            while Current /= Nil_String loop
               Element := Shared.String_Elements.Table (Current);
               Name := Canonical_Case_File_Name (Element.Value);
               Get_Name_String (Element.Value);

               --  If the element has no location, then use the location of
               --  Sources to report possible errors.

               if Element.Location = No_Location then
                  Location := Sources.Location;
               else
                  Location := Element.Location;
               end if;

               --  Check that there is no directory information

               for J in 1 .. Name_Len loop
                  if Is_Directory_Separator (Name_Buffer (J)) then
                     Error_Msg_File_1 := Name;
                     Error_Msg
                       (Data.Flags,
                        "file name cannot include directory information ({)",
                        Location, Project.Project);
                     exit;
                  end if;
               end loop;

               --  Check whether the file is already there: the same file name
               --  may be in the list. If the source is missing, the error will
               --  be on the first mention of the source file name.

               Name_Loc := Source_Names_Htable.Get
                 (Project.Source_Names, Name);

               if Name_Loc = No_Name_Location then
                  Name_Loc :=
                    (Name     => Name,
                     Location => Location,
                     Source   => No_Source,
                     Listed   => True,
                     Found    => False);

               else
                  Name_Loc.Listed := True;
               end if;

               Source_Names_Htable.Set
                 (Project.Source_Names, Name, Name_Loc);

               Current := Element.Next;
            end loop;

            Has_Explicit_Sources := True;
         end;

         --  If we have no Source_Files attribute, check the Source_List_File
         --  attribute.

      elsif not Source_List_File.Default then

         --  Source_List_File is the name of the file that contains the source
         --  file names.

         declare
            Source_File_Path_Name : constant String :=
                                      Path_Name_Of
                                        (File_Name_Type
                                           (Source_List_File.Value),
                                         Project.Project.
                                           Directory.Display_Name);

         begin
            Has_Explicit_Sources := True;

            if Source_File_Path_Name'Length = 0 then
               Error_Msg_File_1 :=
                 File_Name_Type (Source_List_File.Value);
               Error_Msg
                 (Data.Flags,
                  "file with sources { does not exist",
                  Source_List_File.Location, Project.Project);

            else
               Get_Sources_From_File
                 (Source_File_Path_Name, Source_List_File.Location,
                  Project, Data);
            end if;
         end;

      else
         --  Neither Source_Files nor Source_List_File has been specified. Find
         --  all the files that satisfy the naming scheme in all the source
         --  directories.

         Has_Explicit_Sources := False;
      end if;

      --  Remove any exception that is not in the specified list of sources

      if Has_Explicit_Sources then
         declare
            Source : Source_Id;
            Iter   : Source_Iterator;
            NL     : Name_Location;
            Again  : Boolean;
         begin
            Iter_Loop :
            loop
               Again := False;
               Iter := For_Each_Source (Data.Tree, Project.Project);

               Source_Loop :
               loop
                  Source := GPR.Element (Iter);
                  exit Source_Loop when Source = No_Source;

                  if Source.Naming_Exception /= No then
                     NL := Source_Names_Htable.Get
                       (Project.Source_Names, Source.File);

                     if NL /= No_Name_Location and then not NL.Listed then

                        --  Remove the exception

                        Source_Names_Htable.Set
                          (Project.Source_Names,
                           Source.File,
                           No_Name_Location);
                        Remove_Source (Data.Tree, Source, No_Source);

                        if Source.Naming_Exception = Yes then
                           Error_Msg_Name_1 := Name_Id (Source.File);
                           Error_Msg
                             (Data.Flags, "? unknown source file %%",
                              NL.Location, Project.Project);
                        end if;

                        Again := True;
                        exit Source_Loop;
                     end if;
                  end if;

                  Next (Iter);
               end loop Source_Loop;

               exit Iter_Loop when not Again;
            end loop Iter_Loop;
         end;
      end if;

      Search_Directories
        (Project,
         Data            => Data,
         For_All_Sources => Sources.Default and then Source_List_File.Default);

      --  Check if all exceptions have been found

      declare
         Source : Source_Id;
         Iter   : Source_Iterator;
         Found  : Boolean := False;

      begin
         Iter := For_Each_Source (Data.Tree, Project.Project);
         loop
            Source := GPR.Element (Iter);
            exit when Source = No_Source;

            --  If the full source path is unknown for this source_id, there
            --  could be several reasons:
            --    * we simply did not find the file itself, this is an error
            --    * we have a multi-unit source file. Another Source_Id from
            --      the same file has received the full path, so we need to
            --      propagate it.

            if Source.Path = No_Path_Information then
               if Source.Naming_Exception = Yes then
                  if Source.Unit /= No_Unit_Index then
                     Found := False;

                     if Source.Index /= 0 then  --  Only multi-unit files
                        declare
                           S : Source_Id :=
                                 Source_Files_Htable.Get
                                   (Data.Tree.Source_Files_HT, Source.File);

                        begin
                           while S /= null loop
                              if S.Path /= No_Path_Information then
                                 Source.Path := S.Path;
                                 Found := True;

                                 if Current_Verbosity = High then
                                    Debug_Output
                                      ("setting full path for "
                                       & Get_Name_String (Source.File)
                                       & " at" & Source.Index'Img
                                       & " to "
                                       & Get_Name_String (Source.Path.Name));
                                 end if;

                                 exit;
                              end if;

                              S := S.Next_With_File_Name;
                           end loop;
                        end;
                     end if;

                     if not Found then
                        Error_Msg_Name_1 := Name_Id (Source.Display_File);
                        Error_Msg_Name_2 := Source.Unit.Name;
                        Error_Or_Warning
                          (Data.Flags, Data.Flags.Missing_Source_Files,
                           "\source file %% for unit %% not found",
                           No_Location, Project.Project);
                     end if;
                  end if;

                  if Source.Path = No_Path_Information then
                     Remove_Source (Data.Tree, Source, No_Source);
                  end if;

               elsif Source.Naming_Exception = Inherited then
                  Remove_Source (Data.Tree, Source, No_Source);
               end if;
            end if;

            Next (Iter);
         end loop;
      end;

      --  It is an error if a source file name in a source list or in a source
      --  list file is not found.

      if Has_Explicit_Sources then
         declare
            NL          : Name_Location;
            First_Error : Boolean;

         begin
            NL := Source_Names_Htable.Get_First (Project.Source_Names);
            First_Error := True;
            while NL /= No_Name_Location loop
               if not NL.Found then
                  Error_Msg_File_1 := NL.Name;
                  if First_Error then
                     Error_Or_Warning
                       (Data.Flags, Data.Flags.Missing_Source_Files,
                        "source file { not found",
                        NL.Location, Project.Project);
                     First_Error := False;
                  else
                     Error_Or_Warning
                       (Data.Flags, Data.Flags.Missing_Source_Files,
                        "\source file { not found",
                        NL.Location, Project.Project);
                  end if;
               end if;

               NL := Source_Names_Htable.Get_Next (Project.Source_Names);
            end loop;
         end;
      end if;
   end Find_Sources;

   ----------------
   -- Initialize --
   ----------------

   procedure Initialize
     (Data      : out Tree_Processing_Data;
      Tree      : Project_Tree_Ref;
      Node_Tree : GPR.Tree.Project_Node_Tree_Ref;
      Flags     : GPR.Processing_Flags)
   is
   begin
      Data.Tree      := Tree;
      Data.Node_Tree := Node_Tree;
      Data.Flags     := Flags;
   end Initialize;

   ----------
   -- Free --
   ----------

   procedure Free (Data : in out Tree_Processing_Data) is
      pragma Unreferenced (Data);
   begin
      null;
   end Free;

   ----------------
   -- Initialize --
   ----------------

   procedure Initialize
     (Data    : in out Project_Processing_Data;
      Project : Project_Id)
   is
   begin
      Data.Project := Project;
   end Initialize;

   ----------
   -- Free --
   ----------

   procedure Free (Data : in out Project_Processing_Data) is
   begin
      Source_Names_Htable.Reset     (Data.Source_Names);
      Unit_Exceptions_Htable.Reset  (Data.Unit_Exceptions);
      Excluded_Sources_Htable.Reset (Data.Excluded);
   end Free;

   -------------------------------
   -- Check_File_Naming_Schemes --
   -------------------------------

   procedure Check_File_Naming_Schemes
     (Project               : Project_Processing_Data;
      File_Name             : File_Name_Type;
      Alternate_Languages   : out Language_List;
      Language              : out Language_Ptr;
      Display_Language_Name : out Name_Id;
      Unit                  : out Name_Id;
      Lang_Kind             : out Language_Kind;
      Kind                  : out Source_Kind)
   is
      Filename : constant String := Get_Name_String (File_Name);
      Config   : Language_Config;
      Tmp_Lang : Language_Ptr;

      Header_File : Boolean := False;
      --  True if we found at least one language for which the file is a header
      --  In such a case, we search for all possible languages where this is
      --  also a header (C and C++ for instance), since the file might be used
      --  for several such languages.

      procedure Check_File_Based_Lang;
      --  Does the naming scheme test for file-based languages. For those,
      --  there is no Unit. Just check if the file name has the implementation
      --  or, if it is specified, the template suffix of the language.
      --
      --  Returns True if the file belongs to the current language and we
      --  should stop searching for matching languages. Not that a given header
      --  file could belong to several languages (C and C++ for instance). Thus
      --  if we found a header we'll check whether it matches other languages.

      ---------------------------
      -- Check_File_Based_Lang --
      ---------------------------

      procedure Check_File_Based_Lang is
      begin
         if not Header_File
           and then Suffix_Matches (Filename, Config.Naming_Data.Body_Suffix)
         then
            Unit     := No_Name;
            Kind     := Impl;
            Language := Tmp_Lang;

            Debug_Output
              ("implementation of language ", Display_Language_Name);

         elsif Suffix_Matches (Filename, Config.Naming_Data.Spec_Suffix) then
            Debug_Output
              ("header of language ", Display_Language_Name);

            if Header_File then
               Alternate_Languages := new Language_List_Element'
                 (Language => Language,
                  Next     => Alternate_Languages);

            else
               Header_File := True;
               Kind        := Spec;
               Unit        := No_Name;
               Language    := Tmp_Lang;
            end if;
         end if;
      end Check_File_Based_Lang;

   --  Start of processing for Check_File_Naming_Schemes

   begin
      Language              := No_Language_Index;
      Alternate_Languages   := null;
      Display_Language_Name := No_Name;
      Unit                  := No_Name;
      Lang_Kind             := File_Based;
      Kind                  := Spec;

      Tmp_Lang := Project.Project.Languages;
      while Tmp_Lang /= No_Language_Index loop
         if Current_Verbosity = High then
            Debug_Output
              ("testing language "
               & Get_Name_String (Tmp_Lang.Name)
               & " Header_File=" & Header_File'Img);
         end if;

         Display_Language_Name := Tmp_Lang.Display_Name;
         Config := Tmp_Lang.Config;
         Lang_Kind := Config.Kind;

         case Config.Kind is
            when File_Based =>
               Check_File_Based_Lang;
               exit when Kind = Impl;

            when Unit_Based =>

               --  We know it belongs to a least a file_based language, no
               --  need to check unit-based ones.

               if not Header_File then
                  Compute_Unit_Name
                    (File_Name => File_Name,
                     Naming    => Config.Naming_Data,
                     Kind      => Kind,
                     Unit      => Unit,
                     Project   => Project);

                  if Unit /= No_Name then
                     Language    := Tmp_Lang;
                     exit;
                  end if;
               end if;
         end case;

         Tmp_Lang := Tmp_Lang.Next;
      end loop;

      if Language = No_Language_Index then
         Debug_Output ("not a source of any language");
      end if;
   end Check_File_Naming_Schemes;

   -------------------
   -- Override_Kind --
   -------------------

   procedure Override_Kind (Source : Source_Id; Kind : Source_Kind) is
   begin
      --  If the file was previously already associated with a unit, change it

      if Source.Unit /= null
        and then Source.Kind in Spec_Or_Body
        and then Source.Unit.File_Names (Source.Kind) /= null
      then
         --  If we had another file referencing the same unit (for instance it
         --  was in an extended project), that source file is in fact invisible
         --  from now on, and in particular doesn't belong to the same unit.
         --  If the source is an inherited naming exception, then it may not
         --  really exist: the source potentially replaced is left untouched.

         if Source.Unit.File_Names (Source.Kind) /= Source then
            Source.Unit.File_Names (Source.Kind).Unit := No_Unit_Index;
         end if;

         Source.Unit.File_Names (Source.Kind) := null;
      end if;

      Source.Kind := Kind;

      if Current_Verbosity = High and then Source.File /= No_File then
         Debug_Output ("override kind for "
                       & Get_Name_String (Source.File)
                       & " idx=" & Source.Index'Img
                       & " kind=" & Source.Kind'Img);
      end if;

      if Source.Unit /= null then
         if Source.Kind = Spec then
            Source.Unit.File_Names (Spec) := Source;
         else
            Source.Unit.File_Names (Impl) := Source;
         end if;
      end if;
   end Override_Kind;

   ----------------
   -- Check_File --
   ----------------

   procedure Check_File
     (Project           : in out Project_Processing_Data;
      Data              : in out Tree_Processing_Data;
      Source_Dir_Rank   : Natural;
      Path              : Path_Name_Type;
      Display_Path      : Path_Name_Type;
      File_Name         : File_Name_Type;
      Display_File_Name : File_Name_Type;
      Locally_Removed   : Boolean;
      For_All_Sources   : Boolean)
   is
      Name_Loc              : Name_Location :=
                                Source_Names_Htable.Get
                                  (Project.Source_Names, File_Name);
      Check_Name            : Boolean := False;
      Alternate_Languages   : Language_List;
      Language              : Language_Ptr;
      Source                : Source_Id;
      Src_Ind               : Source_File_Index;
      Unit                  : Name_Id;
      Display_Language_Name : Name_Id;
      Lang_Kind             : Language_Kind;
      Kind                  : Source_Kind := Spec;

   begin
      if Current_Verbosity = High then
         Debug_Increase_Indent
           ("checking file (rank=" & Source_Dir_Rank'Img & ")",
            Name_Id (Display_Path));
      end if;

      if Name_Loc = No_Name_Location then
         --  Source_Dir_Rank = 0 mean that source file is from directory
         --  defined in --src-subdir parameter.

         Check_Name := For_All_Sources or else Source_Dir_Rank = 0;

      else
         if Name_Loc.Found then

            --  Check if it is OK to have the same file name in several
            --  source directories.

            if Name_Loc.Source /= No_Source
              and then Source_Dir_Rank = Name_Loc.Source.Source_Dir_Rank
            then
               Error_Msg_File_1 := File_Name;
               Error_Msg
                 (Data.Flags,
                  "{ is found in several source directories",
                  Name_Loc.Location, Project.Project);
            end if;

         else
            Name_Loc.Found := True;

            Source_Names_Htable.Set
              (Project.Source_Names, File_Name, Name_Loc);

            if Name_Loc.Source = No_Source then
               Check_Name := True;

            else
               --  Set the full path for the source_id (which might have been
               --  created when parsing the naming exceptions, and therefore
               --  might not have the full path).
               --  We only set this for this source_id, but not for other
               --  source_id in the same file (case of multi-unit source files)
               --  For the latter, they will be set in Find_Sources when we
               --  check that all source_id have known full paths.
               --  Doing this later saves one htable lookup per file in the
               --  common case where the user is not using multi-unit files.

               Name_Loc.Source.Path := (Path, Display_Path);

               Source_Paths_Htable.Set
                 (Data.Tree.Source_Paths_HT, Path, Name_Loc.Source);

               --  Check if this is a subunit

               if Name_Loc.Source.Unit /= No_Unit_Index
                 and then Name_Loc.Source.Kind = Impl
               then
                  Src_Ind := Sinput.Load_File
                    (Get_Name_String (Display_Path));

                  if Source_File_Is_Subunit (Src_Ind) then
                     Override_Kind (Name_Loc.Source, Sep);
                  end if;
               end if;

               --  If this is an inherited naming exception, make sure that
               --  the naming exception it replaces is no longer a source.

               if Name_Loc.Source.Naming_Exception = Inherited then
                  declare
                     Proj : Project_Id := Name_Loc.Source.Project.Extends;
                     Iter : Source_Iterator;
                     Src  : Source_Id;
                  begin
                     while Proj /= No_Project loop
                        Iter := For_Each_Source (Data.Tree, Proj);
                        Src := GPR.Element (Iter);
                        while Src /= No_Source loop
                           if Src.File = Name_Loc.Source.File then
                              Src.Replaced_By := Name_Loc.Source;
                              exit;
                           end if;

                           Next (Iter);
                           Src := GPR.Element (Iter);
                        end loop;

                        Proj := Proj.Extends;
                     end loop;
                  end;

                  if Name_Loc.Source.Unit /= No_Unit_Index then
                     if Name_Loc.Source.Kind = Spec then
                        Name_Loc.Source.Unit.File_Names (Spec) :=
                          Name_Loc.Source;

                     elsif Name_Loc.Source.Kind = Impl then
                        Name_Loc.Source.Unit.File_Names (Impl) :=
                          Name_Loc.Source;
                     end if;

                     Units_Htable.Set
                       (Data.Tree.Units_HT,
                        Name_Loc.Source.Unit.Name,
                        Name_Loc.Source.Unit);
                  end if;
               end if;
            end if;
         end if;
      end if;

      if Check_Name then
         Check_File_Naming_Schemes
           (Project               => Project,
            File_Name             => File_Name,
            Alternate_Languages   => Alternate_Languages,
            Language              => Language,
            Display_Language_Name => Display_Language_Name,
            Unit                  => Unit,
            Lang_Kind             => Lang_Kind,
            Kind                  => Kind);

         if Language = No_Language_Index then

            --  A file name in a list must be a source of a language.

            if Data.Flags.Error_On_Unknown_Language
              and then not Languages_Are_Restricted
              and then Name_Loc.Found
            then
               Error_Msg_File_1 := File_Name;
               Error_Msg
                 (Data.Flags,
                  "language unknown for {",
                  Name_Loc.Location, Project.Project);
            end if;

         else
            Add_Source
              (Id                  => Source,
               Project             => Project.Project,
               Source_Dir_Rank     => Source_Dir_Rank,
               Lang_Id             => Language,
               Kind                => Kind,
               Data                => Data,
               Alternate_Languages => Alternate_Languages,
               File_Name           => File_Name,
               Display_File        => Display_File_Name,
               Unit                => Unit,
               Locally_Removed     => Locally_Removed,
               Path                => (Path, Display_Path));

            if Source /= null then
               Source.In_Src_Subdir := Source_Dir_Rank = 0;
            end if;

            --  If it is a source specified in a list, update the entry in
            --  the Source_Names table.

            if Name_Loc.Found and then Name_Loc.Source = No_Source then
               Name_Loc.Source := Source;
               Source_Names_Htable.Set
                 (Project.Source_Names, File_Name, Name_Loc);
            end if;
         end if;
      end if;

      Debug_Decrease_Indent;
   end Check_File;

   ---------------------------------
   -- Expand_Subdirectory_Pattern --
   ---------------------------------

   procedure Expand_Subdirectory_Pattern
     (Project       : Project_Id;
      Data          : in out Tree_Processing_Data;
      Patterns      : String_List_Id;
      Ignore        : String_List_Id;
      Search_For    : Search_Type;
      Resolve_Links : Boolean;
      Callback      : access procedure
        (Path : Path_Information; Pattern_Index : Natural))
   is
      Shared : constant Shared_Project_Tree_Data_Access := Data.Tree.Shared;

      package Recursive_Dirs renames Path_Name_HTable;
      --  Hash table stores recursive source directories, to avoid looking
      --  several times, and to avoid cycles that may be introduced by symbolic
      --  links.

      File_Pattern : GNAT.Regexp.Regexp;
      --  Pattern to use when matching file names

      Visited : Recursive_Dirs.Instance;

      procedure Find_Pattern
        (Pattern_Id : Name_Id;
         Rank       : Natural;
         Location   : Source_Ptr);
      --  Find a specific pattern

      function Recursive_Find_Dirs
        (Path : Path_Information;
         Rank : Natural) return Boolean;
      --  Search all the subdirectories (recursively) of Path.
      --  Return True if at least one file or directory was processed

      function Subdirectory_Matches
        (Path : Path_Information;
         Rank : Natural) return Boolean;
      --  Called when a matching directory was found. If the user is in fact
      --  searching for files, we then search for those files matching the
      --  pattern within the directory.
      --  Return True if at least one file or directory was processed

      --------------------------
      -- Subdirectory_Matches --
      --------------------------

      function Subdirectory_Matches
        (Path : Path_Information;
         Rank : Natural) return Boolean
      is
         Dir     : Dir_Type;
         Name    : String (1 .. 250);
         Last    : Natural;
         Found   : Path_Information;
         Success : Boolean := False;

      begin
         case Search_For is
            when Search_Source_Directories =>
               Callback (Path, Rank);
               return True;

            when Search_Project_Files =>
               Open (Dir, Get_Name_String (Path.Display_Name));

               loop
                  Read (Dir, Name, Last);
                  exit when Last = 0;

                  if Name (Name'First .. Last) /= "."
                    and then Name (Name'First .. Last) /= ".."
                    and then Match (Name (Name'First .. Last), File_Pattern)
                  then
                     Get_Name_String (Path.Display_Name);
                     Add_Str_To_Name_Buffer (Name (Name'First .. Last));

                     Found.Display_Name := Name_Find;
                     Canonical_Case_File_Name (Name_Buffer (1 .. Name_Len));
                     Found.Name := Name_Find;

                     Callback (Found, Rank);
                     Success := True;
                  end if;
               end loop;

               Close (Dir);

               return Success;
         end case;

      exception
         when Directory_Error =>
            return False;
      end Subdirectory_Matches;

      -------------------------
      -- Recursive_Find_Dirs --
      -------------------------

      function Recursive_Find_Dirs
        (Path : Path_Information;
         Rank : Natural) return Boolean
      is
         Path_Str : constant String := Get_Name_String (Path.Display_Name);
         Dir      : Dir_Type;
         Name     : String (1 .. 250);
         Last     : Natural;
         Success  : Boolean := False;

      begin
         Debug_Output ("looking for subdirs of ", Name_Id (Path.Display_Name));

         if Recursive_Dirs.Get (Visited, Path.Name) then
            return Success;
         end if;

         Recursive_Dirs.Set (Visited, Path.Name, True);

         Success := Subdirectory_Matches (Path, Rank) or Success;

         Open (Dir, Path_Str);

         loop
            Read (Dir, Name, Last);
            exit when Last = 0;

            if Name (1 .. Last) /= "." and then Name (1 .. Last) /= ".." then
               declare
                  Path_Name : constant String :=
                                Normalize_Pathname
                                  (Name           => Name (1 .. Last),
                                   Directory      => Path_Str,
                                   Resolve_Links  => Resolve_Links)
                                & Directory_Separator;

                  Path2 : Path_Information;
                  OK    : Boolean := True;

               begin
                  if Is_Directory (Path_Name) then
                     if Ignore /= Nil_String then
                        declare
                           Dir_Name : String := Name (1 .. Last);
                           List     : String_List_Id := Ignore;

                        begin
                           Canonical_Case_File_Name (Dir_Name);

                           while List /= Nil_String loop
                              Get_Name_String
                                (Shared.String_Elements.Table (List).Value);
                              if Name_Len > 0 then
                                 Canonical_Case_File_Name
                                   (Name_Buffer (1 .. Name_Len));

                                 File_Pattern := Compile
                                   (Name_Buffer (1 .. Name_Len),
                                    Glob           => True,
                                    Case_Sensitive => File_Names_Case_Sensitive
                                   );

                                 OK := not Match (Dir_Name, File_Pattern);
                                 exit when not OK;
                              end if;
                              List := Shared.String_Elements.Table (List).Next;
                           end loop;
                        end;
                     end if;

                     if OK then
                        Path2.Display_Name := Get_Path_Name_Id (Path_Name);

                        Canonical_Case_File_Name (Name_Buffer (1 .. Name_Len));
                        Path2.Name := Name_Find;

                        Success :=
                          Recursive_Find_Dirs (Path2, Rank) or Success;
                     end if;
                  end if;
               end;
            end if;
         end loop;

         Close (Dir);

         return Success;

      exception
         when Directory_Error =>
            return Success;
      end Recursive_Find_Dirs;

      ------------------
      -- Find_Pattern --
      ------------------

      procedure Find_Pattern
        (Pattern_Id : Name_Id;
         Rank       : Natural;
         Location   : Source_Ptr)
      is
         Pattern     : constant String := Get_Name_String (Pattern_Id);
         Pattern_End : Natural := Pattern'Last;
         Recursive   : Boolean;
         Dir         : File_Name_Type;
         Path_Name   : Path_Information;
         Dir_Exists  : Boolean;
         Success     : Boolean;
         Has_Error   : Boolean := False;
         Msg_Mode    : Error_Warning;

      begin
         Debug_Increase_Indent ("Find_Pattern", Pattern_Id);

         --  If we are looking for files, find the pattern for the files

         if Search_For = Search_Project_Files then
            while Pattern_End >= Pattern'First
              and then not Is_Directory_Separator (Pattern (Pattern_End))
            loop
               Pattern_End := Pattern_End - 1;
            end loop;

            if Pattern_End = Pattern'Last then
               Error_Msg_File_1 := File_Name_Type (Pattern_Id);
               Error_Or_Warning
                 (Data.Flags, Data.Flags.Missing_Source_Files,
                  "Missing file name or pattern in {", Location, Project);
               Debug_Decrease_Indent;
               return;
            end if;

            if Current_Verbosity = High then
               Debug_Indent;
               Write_Str ("file_pattern=");
               Write_Str (Pattern (Pattern_End + 1 .. Pattern'Last));
               Write_Str (" dir_pattern=");
               Write_Line (Pattern (Pattern'First .. Pattern_End));
            end if;

            File_Pattern := Compile
              (Pattern (Pattern_End + 1 .. Pattern'Last),
               Glob           => True,
               Case_Sensitive => File_Names_Case_Sensitive);

            --  If we had just "*.gpr", this is equivalent to "./*.gpr"

            if Pattern_End > Pattern'First then
               Pattern_End := Pattern_End - 1; --  Skip directory separator
            end if;
         end if;

         Recursive :=
           Pattern_End - 1 >= Pattern'First
           and then Pattern (Pattern_End - 1 .. Pattern_End) = "**"
           and then
             (Pattern_End - 1 = Pattern'First
               or else Is_Directory_Separator (Pattern (Pattern_End - 2)));

         if Recursive then
            Pattern_End := Pattern_End - 2;
            if Pattern_End > Pattern'First then
               Pattern_End := Pattern_End - 1; --  Skip '/'
            end if;
         end if;

         Name_Len := Pattern_End - Pattern'First + 1;
         Name_Buffer (1 .. Name_Len) := Pattern (Pattern'First .. Pattern_End);
         Dir := Name_Find;

         Locate_Directory
           (Project     => Project,
            Name        => Dir,
            Path        => Path_Name,
            Dir_Exists  => Dir_Exists,
            Data        => Data,
            Must_Exist  => False);

         if not Dir_Exists then
            Msg_Mode := (case Search_For is
                             when Search_Source_Directories =>
                               Data.Flags.Missing_Source_Files,
                             when Search_Project_Files =>
                               Data.Flags.Missing_Project_Files);
            Error_Or_Warning
              (Data.Flags, Msg_Mode,
               '"' & Mask_Control_Characters (Get_Name_String (Dir))
               & """ is not a valid directory",
               Location, Project);
            Has_Error := Msg_Mode = Error;
         end if;

         if not Has_Error then
            --  Links have been resolved if necessary, and Path_Name
            --  always ends with a directory separator.

            if Recursive then
               Success := Recursive_Find_Dirs (Path_Name, Rank);
            else
               Success := Subdirectory_Matches (Path_Name, Rank);
            end if;

            if not Success then
               case Search_For is
                  when Search_Source_Directories =>
                     null;  --  Error can't occur

                  when Search_Project_Files =>
                     Error_Or_Warning
                       (Data.Flags, Data.Flags.Missing_Project_Files,
                        "file """
                        & Mask_Control_Characters
                            (Get_Name_String (Pattern_Id))
                        & """ not found",
                        Location, Project);
               end case;
            end if;
         end if;

         Debug_Decrease_Indent ("done Find_Pattern");
      end Find_Pattern;

      --  Local variables

      Pattern_Id : String_List_Id := Patterns;
      Element    : String_Element;
      Rank       : Natural := 1;

   --  Start of processing for Expand_Subdirectory_Pattern

   begin
      while Pattern_Id /= Nil_String loop
         Element := Shared.String_Elements.Table (Pattern_Id);

         if Element.Value /= No_Name then
            Find_Pattern (Element.Value, Rank, Element.Location);
         end if;

         Rank := Rank + 1;
         Pattern_Id := Element.Next;
      end loop;

      Recursive_Dirs.Reset (Visited);
   end Expand_Subdirectory_Pattern;

   ------------------------
   -- Search_Directories --
   ------------------------

   procedure Search_Directories
     (Project         : in out Project_Processing_Data;
      Data            : in out Tree_Processing_Data;
      For_All_Sources : Boolean)
   is
      Shared : constant Shared_Project_Tree_Data_Access := Data.Tree.Shared;

      Source_Dir        : String_List_Id;
      Element           : String_Element;
      Src_Dir_Rank      : Number_List_Index;
      Num_Nod           : Number_Node;
      Dir               : Dir_Type;
      Name              : String (1 .. 1_000);
      Last              : Natural;
      File_Name         : File_Name_Type;
      Display_File_Name : File_Name_Type;

   begin
      Debug_Increase_Indent ("looking for sources of", Project.Project.Name);

      --  Loop through subdirectories

      Src_Dir_Rank := Project.Project.Source_Dir_Ranks;

      Source_Dir := Project.Project.Source_Dirs;
      while Source_Dir /= Nil_String loop
         begin
            Num_Nod := Shared.Number_Lists.Table (Src_Dir_Rank);
            Element := Shared.String_Elements.Table (Source_Dir);

            --  Use Element.Value in this test, not Display_Value, because we
            --  want the symbolic links to be resolved when appropriate.

            if Element.Value /= No_Name then
               declare
                  Source_Directory : constant String :=
                                       Get_Name_String (Element.Value)
                                       & Directory_Separator;

                  Dir_Last : constant Natural :=
                               Compute_Directory_Last (Source_Directory);

                  Display_Source_Directory : constant String :=
                                               Get_Name_String
                                                 (Element.Display_Value)
                                                  & Directory_Separator;
                  --  Display_Source_Directory is to allow us to open a UTF-8
                  --  encoded directory on Windows.

               begin
                  if Current_Verbosity = High then
                     Debug_Increase_Indent
                       ("Source_Dir (node=" & Num_Nod.Number'Img & ") """
                        & Source_Directory (Source_Directory'First .. Dir_Last)
                        & '"');
                  end if;

                  --  We look to every entry in the source directory

                  Open (Dir, Display_Source_Directory);

                  loop
                     Read (Dir, Name, Last);
                     exit when Last = 0;

                     --  In fast project loading mode (without -eL), the user
                     --  guarantees that no directory has a name which is a
                     --  valid source name, so we can avoid doing a system call
                     --  here. This provides a very significant speed up on
                     --  slow file systems (remote files for instance).

                     if not Opt.Follow_Links_For_Files
                       or else Is_Regular_File
                                 (Display_Source_Directory & Name (1 .. Last))
                     then
                        Name_Len := Last;
                        Name_Buffer (1 .. Name_Len) := Name (1 .. Last);
                        Display_File_Name := Name_Find;

                        if Osint.File_Names_Case_Sensitive then
                           File_Name := Display_File_Name;
                        else
                           Canonical_Case_File_Name
                             (Name_Buffer (1 .. Name_Len));
                           File_Name := Name_Find;
                        end if;

                        declare
                           Path_Name : constant String :=
                                         Normalize_Pathname
                                           (Name (1 .. Last),
                                            Directory       =>
                                              Source_Directory
                                                (Source_Directory'First ..
                                                 Dir_Last),
                                            Resolve_Links   =>
                                              Opt.Follow_Links_For_Files,
                                            Case_Sensitive => True);

                           Path      : Path_Name_Type;
                           FF        : File_Found :=
                                         Excluded_Sources_Htable.Get
                                           (Project.Excluded, File_Name);
                           To_Remove : Boolean := False;

                        begin
                           Name_Len := Path_Name'Length;
                           Name_Buffer (1 .. Name_Len) := Path_Name;

                           if Osint.File_Names_Case_Sensitive then
                              Path := Name_Find;
                           else
                              Canonical_Case_File_Name
                                (Name_Buffer (1 .. Name_Len));
                              Path := Name_Find;
                           end if;

                           if FF /= No_File_Found then
                              if not FF.Found then
                                 FF.Found := True;
                                 Excluded_Sources_Htable.Set
                                   (Project.Excluded, File_Name, FF);

                                 Debug_Output
                                   ("excluded source ",
                                    Name_Id (Display_File_Name));

                                 --  Will mark the file as removed, but we
                                 --  still need to add it to the list: if we
                                 --  don't, the file will not appear in the
                                 --  mapping file and will cause the compiler
                                 --  to fail.

                                 To_Remove := True;
                              end if;
                           end if;

                           --  Preserve the user's original casing and use of
                           --  links. The display_value (a directory) already
                           --  ends with a directory separator by construction,
                           --  so no need to add one.

                           Get_Name_String (Element.Display_Value);
                           Get_Name_String_And_Append
                             (Name_Id (Display_File_Name));

                           Check_File
                             (Project           => Project,
                              Source_Dir_Rank   => Num_Nod.Number,
                              Data              => Data,
                              Path              => Path,
                              Display_Path      => Name_Find,
                              File_Name         => File_Name,
                              Locally_Removed   => To_Remove,
                              Display_File_Name => Display_File_Name,
                              For_All_Sources   => For_All_Sources);
                        end;

                     else
                        if Current_Verbosity = High then
                           Debug_Output ("ignore " & Name (1 .. Last));
                        end if;
                     end if;
                  end loop;

                  Debug_Decrease_Indent;
                  Close (Dir);
               end;
            end if;

         exception
            when Directory_Error =>
               null;
         end;

         Source_Dir := Element.Next;
         Src_Dir_Rank := Num_Nod.Next;
      end loop;

      Debug_Decrease_Indent ("end looking for sources.");
   end Search_Directories;

   ----------------------------
   -- Load_Naming_Exceptions --
   ----------------------------

   procedure Load_Naming_Exceptions
     (Project : in out Project_Processing_Data;
      Data    : in out Tree_Processing_Data)
   is
      Source : Source_Id;
      Iter   : Source_Iterator;

   begin
      Iter := For_Each_Source (Data.Tree, Project.Project);
      loop
         Source := GPR.Element (Iter);
         exit when Source = No_Source;

         --  An excluded file cannot also be an exception file name

         if Excluded_Sources_Htable.Get (Project.Excluded, Source.File) /=
                                                                 No_File_Found
         then
            Error_Msg_File_1 := Source.File;
            Error_Msg
              (Data.Flags,
               "\{ cannot be both excluded and an exception file name",
               No_Location, Project.Project);
         end if;

         Debug_Output
           ("naming exception: adding source file to source_Names: ",
            Name_Id (Source.File));

         Source_Names_Htable.Set
           (Project.Source_Names,
            K => Source.File,
            E => Name_Location'
                  (Name     => Source.File,
                   Location => Source.Location,
                   Source   => Source,
                   Listed   => False,
                   Found    => False));

         --  If this is an Ada exception, record in table Unit_Exceptions

         if Source.Unit /= No_Unit_Index then
            declare
               Unit_Except : Unit_Exception :=
                               Unit_Exceptions_Htable.Get
                                 (Project.Unit_Exceptions, Source.Unit.Name);

            begin
               Unit_Except.Name := Source.Unit.Name;

               if Source.Kind = Spec then
                  Unit_Except.Spec := Source.File;
               else
                  Unit_Except.Impl := Source.File;
               end if;

               Unit_Exceptions_Htable.Set
                 (Project.Unit_Exceptions, Source.Unit.Name, Unit_Except);
            end;
         end if;

         Next (Iter);
      end loop;
   end Load_Naming_Exceptions;

   ----------------------
   -- Look_For_Sources --
   ----------------------

   procedure Look_For_Sources
     (Project : in out Project_Processing_Data;
      Data    : in out Tree_Processing_Data)
   is
      Object_Files : Object_File_Names_Htable.Instance;
      Iter         : Source_Iterator;
      Src          : Source_Id;

      procedure Check_Object (Src : Source_Id);
      --  Check if object file name of Src is already used in the project tree,
      --  and report an error if so.

      procedure Check_Object_Files;
      --  Check that no two sources of this project have the same object file

      procedure Mark_Excluded_Sources;
      --  Mark as such the sources that are declared as excluded

      procedure Check_Missing_Sources;
      --  Check whether one of the languages has no sources, and report an
      --  error when appropriate

      procedure Get_Sources_From_Source_Info;
      --  Get the source information from the tables that were created when a
      --  source info file was read.

      ---------------------------
      -- Check_Missing_Sources --
      ---------------------------

      procedure Check_Missing_Sources is
         Extending    : constant Boolean :=
                          Project.Project.Extends /= No_Project;
         Language     : Language_Ptr;
         Source       : Source_Id;
         Alt_Lang     : Language_List;
         Continuation : Boolean := False;
         Iter         : Source_Iterator;
      begin
         if not Project.Project.Externally_Built and then not Extending then
            Language := Project.Project.Languages;
            while Language /= No_Language_Index loop
               if Is_Allowed_Language (Language.Name) then
                  --  If there are no sources for this language, check if there
                  --  are sources for which this is an alternate language.

                  if Language.First_Source = No_Source
                    and then (Data.Flags.Require_Sources_Other_Lang
                              or else Language.Name = Name_Ada)
                  then
                     Iter := For_Each_Source (In_Tree => Data.Tree,
                                              Project => Project.Project);
                     Source_Loop : loop
                        Source := Element (Iter);
                        exit Source_Loop when Source = No_Source
                          or else Source.Language = Language;

                        Alt_Lang := Source.Alternate_Languages;
                        while Alt_Lang /= null loop
                           exit Source_Loop when Alt_Lang.Language = Language;
                           Alt_Lang := Alt_Lang.Next;
                        end loop;

                        Next (Iter);
                     end loop Source_Loop;

                     if Source = No_Source then
                        Report_No_Sources
                          (Project.Project,
                           Get_Name_String (Language.Display_Name),
                           Data,
                           Project.Source_List_File_Location,
                           Continuation);
                        Continuation := True;
                     end if;
                  end if;
               end if;

               Language := Language.Next;
            end loop;
         end if;
      end Check_Missing_Sources;

      ------------------
      -- Check_Object --
      ------------------

      procedure Check_Object (Src : Source_Id) is
         Source : Source_Id;

      begin
         Source := Object_File_Names_Htable.Get (Object_Files, Src.Object);

         --  We cannot just check on "Source /= Src", since we might have
         --  two different entries for the same file (and since that's
         --  the same file it is expected that it has the same object)

         if Source /= No_Source
           and then Source.Replaced_By = No_Source
           and then Source.Path /= Src.Path
           and then Source.Index = 0
           and then Src.Index = 0
           and then Is_Extending (Src.Project, Source.Project)
         then
            Error_Msg_File_1 := Src.File;
            Error_Msg_File_2 := Source.File;
            Error_Msg
              (Data.Flags,
               "\{ and { have the same object file name",
               No_Location, Project.Project);

         else
            Object_File_Names_Htable.Set (Object_Files, Src.Object, Src);
         end if;
      end Check_Object;

      ---------------------------
      -- Mark_Excluded_Sources --
      ---------------------------

      procedure Mark_Excluded_Sources is
         Source   : Source_Id := No_Source;
         Excluded : File_Found;
         Proj     : Project_Id;

      begin
         --  Minor optimization: if there are no excluded files, no need to
         --  traverse the list of sources. We cannot however also check whether
         --  the existing exceptions have ".Found" set to True (indicating we
         --  found them before) because we need to do some final processing on
         --  them in any case.

         if Excluded_Sources_Htable.Get_First (Project.Excluded) /=
                                                             No_File_Found
         then
            --  The excluded files are not only those declared in the current
            --  project, but also those declared in the projects that extend
            --  the current project, if there are any.

            Proj := Project.Project;
            while Proj /= No_Project loop
               Iter := For_Each_Source (Data.Tree, Proj);
               while GPR.Element (Iter) /= No_Source loop
                  Source   := GPR.Element (Iter);
                  Excluded := Excluded_Sources_Htable.Get
                    (Project.Excluded, Source.File);

                  if Excluded /= No_File_Found then
                     Source.In_Interfaces   := False;
                     Source.Locally_Removed := True;

                     if Proj = Project.Project then
                        Source.Suppressed := True;
                     end if;

                     if Current_Verbosity = High then
                        Debug_Indent;
                        Write_Str ("removing file ");
                        Write_Line
                          (Get_Name_String (Excluded.File)
                           & " " & Get_Name_String (Source.Project.Name));
                     end if;

                     Excluded_Sources_Htable.Remove
                       (Project.Excluded, Source.File);
                  end if;

                  Next (Iter);
               end loop;

               Proj := Proj.Extends;
            end loop;
         end if;

         --  If we have any excluded element left, that means we did not find
         --  the source file

         Excluded := Excluded_Sources_Htable.Get_First (Project.Excluded);
         while Excluded /= No_File_Found loop
            if not Excluded.Found then

               --  Check if the file belongs to another imported project to
               --  provide a better error message.

               Src := GPR.Find_Source
                 (In_Tree          => Data.Tree,
                  Project          => Project.Project,
                  In_Imported_Only => True,
                  Base_Name        => Excluded.File);

               if (Src = No_Source and then Excluded.Project = Project.Project)
                 or else Src /= No_Source
               then
                  Error_Msg_File_1 := Excluded.File;
                  Error_Msg
                    (Data.Flags,
                     (if Excluded.Excl_File = No_File then ""
                      else "in " & Get_Name_String (Excluded.Excl_File)
                      & ':' & No_Space_Img (Excluded.Excl_Line) & ": ")
                      & (if Src = No_Source then "unknown file {"
                         else "cannot remove a source from an imported project"
                         & ": {"),
                     Excluded.Location, Project.Project);
               end if;
            end if;

            Excluded := Excluded_Sources_Htable.Get_Next (Project.Excluded);
         end loop;
      end Mark_Excluded_Sources;

      ------------------------
      -- Check_Object_Files --
      ------------------------

      procedure Check_Object_Files is
         Iter    : Source_Iterator;
         Src_Id  : Source_Id;
         Src_Ind : Source_File_Index;

      begin
         Iter := For_Each_Source (Data.Tree);
         loop
            Src_Id := GPR.Element (Iter);
            exit when Src_Id = No_Source;

            if Is_Compilable (Src_Id)
              and then Src_Id.Language.Config.Object_Generated
              and then Is_Extending (Project.Project, Src_Id.Project)
            then
               if Src_Id.Unit = No_Unit_Index then
                  if Src_Id.Kind = Impl then
                     Check_Object (Src_Id);
                  end if;

               else
                  case Src_Id.Kind is
                     when Spec =>
                        if Other_Part (Src_Id) = No_Source then
                           Check_Object (Src_Id);
                        end if;

                     when Sep =>
                        null;

                     when Impl =>
                        if Other_Part (Src_Id) /= No_Source then
                           Check_Object (Src_Id);

                        else
                           --  Check if it is a subunit

                           Src_Ind :=
                             Sinput.Load_File
                               (Get_Name_String (Src_Id.Path.Display_Name));

                           if Source_File_Is_Subunit (Src_Ind) then
                              Override_Kind (Src_Id, Sep);
                           else
                              Check_Object (Src_Id);
                           end if;
                        end if;
                  end case;
               end if;
            end if;

            Next (Iter);
         end loop;
      end Check_Object_Files;

      ----------------------------------
      -- Get_Sources_From_Source_Info --
      ----------------------------------

      procedure Get_Sources_From_Source_Info is
         Iter    : Source_Info_Iterator;
         Src     : Source_Info;
         Id      : Source_Id;
         Lang_Id : Language_Ptr;

      begin
         Initialize (Iter, Project.Project.Name);

         loop
            Src := Source_Info_Of (Iter);

            exit when Src = No_Source_Info;

            Id := new Source_Data;

            Id.Project := Project.Project;

            Lang_Id := Project.Project.Languages;
            while Lang_Id /= No_Language_Index
              and then Lang_Id.Name /= Src.Language
            loop
               Lang_Id := Lang_Id.Next;
            end loop;

            if Lang_Id = No_Language_Index then
               GPR.Com.Fail
                 ("unknown language " &
                  Get_Name_String (Src.Language) &
                  " for project " &
                  Get_Name_String (Src.Project) &
                  " in source info file");
            end if;

            Id.Language := Lang_Id;
            Id.Kind     := Src.Kind;
            Id.Index    := Src.Index;

            Id.Path :=
              (Display_Name => Path_Name_Type (Src.Display_Path_Name),
               Name         => Path_Name_Type (Src.Path_Name));

            Id.File := Get_File_Name_Id
              (Directories.Simple_Name (Get_Name_String (Src.Path_Name)));

            Id.Next_With_File_Name :=
              Source_Files_Htable.Get (Data.Tree.Source_Files_HT, Id.File);
            Source_Files_Htable.Set (Data.Tree.Source_Files_HT, Id.File, Id);

            Id.Display_File := Get_File_Name_Id
              (Directories.Simple_Name
                 (Get_Name_String (Src.Display_Path_Name)));

            Id.Dep_Name         :=
              Dependency_Name (Id.File, Id.Language.Config.Dependency_Kind);
            Id.Naming_Exception := Src.Naming_Exception;
            Id.Object           :=
              Object_Name (Id.File, Id.Language.Config.Object_File_Suffix);
            Id.Switches         := Switches_Name (Id.File);

            --  Add the source id to the Unit_Sources_HT hash table, if the
            --  unit name is not null.

            if Src.Unit_Name /= No_Name then
               declare
                  UData : Unit_Index :=
                    Units_Htable.Get (Data.Tree.Units_HT, Src.Unit_Name);
               begin
                  if UData = No_Unit_Index then
                     UData := new Unit_Data;
                     UData.Name := Src.Unit_Name;
                     Units_Htable.Set
                       (Data.Tree.Units_HT, Src.Unit_Name, UData);
                  end if;

                  Id.Unit := UData;
               end;

               --  Note that this updates Unit information as well

               Override_Kind (Id, Id.Kind);
            end if;

            if Src.Index /= 0 then
               Project.Project.Has_Multi_Unit_Sources := True;
            end if;

            --  Add the source to the language list

            Id.Next_In_Lang := Id.Language.First_Source;
            Id.Language.First_Source := Id;

            Next (Iter);
         end loop;
      end Get_Sources_From_Source_Info;

   --  Start of processing for Look_For_Sources

   begin
      if Data.Tree.Source_Info_File_Exists then
         Get_Sources_From_Source_Info;

      else
         if Project.Project.Source_Dirs /= Nil_String then
            Find_Excluded_Sources (Project, Data);

            if Project.Project.Languages /= No_Language_Index then
               Load_Naming_Exceptions (Project, Data);
               Find_Sources (Project, Data);
               Mark_Excluded_Sources;
               Check_Object_Files;
               Check_Missing_Sources;
            end if;
         end if;

         Object_File_Names_Htable.Reset (Object_Files);
      end if;
   end Look_For_Sources;

   ------------------
   -- Path_Name_Of --
   ------------------

   function Path_Name_Of
     (File_Name : File_Name_Type;
      Directory : Path_Name_Type) return String
   is
      Result        : String_Access;
      The_Directory : constant String := Get_Name_String (Directory);

   begin
      Debug_Output ("Path_Name_Of file name=", Name_Id (File_Name));
      Debug_Output ("Path_Name_Of directory=", Name_Id (Directory));
      Get_Name_String (File_Name);
      Result :=
        Locate_Regular_File
          (File_Name => Name_Buffer (1 .. Name_Len),
           Path      => The_Directory);

      if Result = null then
         return "";
      else
         declare
            R : constant String := Result.all;
         begin
            Free (Result);
            return R;
         end;
      end if;
   end Path_Name_Of;

   -------------------
   -- Remove_Source --
   -------------------

   procedure Remove_Source
     (Tree        : Project_Tree_Ref;
      Id          : Source_Id;
      Replaced_By : Source_Id)
   is
      Source : Source_Id;

   begin
      if Current_Verbosity = High then
         Debug_Indent;
         Write_Str ("removing source ");
         Write_Str (Get_Name_String (Id.File));

         if Id.Index /= 0 then
            Write_Str (" at" & Id.Index'Img);
         end if;

         Write_Eol;
      end if;

      if Replaced_By /= No_Source then
         Id.Replaced_By := Replaced_By;
         Replaced_By.Declared_In_Interfaces := Id.Declared_In_Interfaces;

         if Id.File /= Replaced_By.File then
            declare
               Replacement : constant File_Name_Type :=
                               Replaced_Source_HTable.Get
                                 (Tree.Replaced_Sources, Id.File);

            begin
               Replaced_Source_HTable.Set
                 (Tree.Replaced_Sources, Id.File, Replaced_By.File);

               if Replacement = No_File then
                  Tree.Replaced_Source_Number :=
                    Tree.Replaced_Source_Number + 1;
               end if;
            end;
         end if;
      end if;

      Id.In_Interfaces := False;
      Id.Locally_Removed := True;

      --  ??? Should we remove the source from the unit ? The file is not used,
      --  so probably should not be referenced from the unit. On the other hand
      --  it might give useful additional info
      --        if Id.Unit /= null then
      --           Id.Unit.File_Names (Id.Kind) := null;
      --        end if;

      Source := Id.Language.First_Source;

      if Source = Id then
         Id.Language.First_Source := Id.Next_In_Lang;

      else
         --  Do not crash if the source cannot be found

         while Source /= No_Source and then Source.Next_In_Lang /= Id loop
            Source := Source.Next_In_Lang;
         end loop;

         if Source /= No_Source then
            Source.Next_In_Lang := Id.Next_In_Lang;
         end if;
      end if;
   end Remove_Source;

   -----------------------
   -- Report_No_Sources --
   -----------------------

   procedure Report_No_Sources
     (Project      : Project_Id;
      Lang_Name    : String;
      Data         : Tree_Processing_Data;
      Location     : Source_Ptr;
      Continuation : Boolean := False)
   is
      Language_Name : String (1 .. Lang_Name'Length * 2);
      Language_Last : Natural := 0;
   begin
      --  Make sure that the language name will be displayed as is in the
      --  error message and not modified, for example if it is in capital
      --  letters.

      for J in Lang_Name'Range loop
         Language_Last := Language_Last + 1;
         Language_Name (Language_Last) := ''';
         Language_Last := Language_Last + 1;
         Language_Name (Language_Last) := Lang_Name (J);
      end loop;

      case Data.Flags.When_No_Sources is
         when Silent | Decide_Later =>
            null;

         when Warning | Error =>
            Error_Msg_Warn := Data.Flags.When_No_Sources = Warning;

            Error_Msg
              (Data.Flags,
               (if Continuation then "\" else "")
               & "<there are no sources of language """ & Language_Name
               & """ in this project",
               Location, Project);
      end case;
   end Report_No_Sources;

   ----------------------
   -- Show_Source_Dirs --
   ----------------------

   procedure Show_Source_Dirs
     (Project : Project_Id;
      Shared  : Shared_Project_Tree_Data_Access)
   is
      Current : String_List_Id;
      Element : String_Element;

   begin
      if Project.Source_Dirs = Nil_String then
         Debug_Output ("no Source_Dirs");
      else
         Debug_Increase_Indent ("Source_Dirs:");

         Current := Project.Source_Dirs;
         while Current /= Nil_String loop
            Element := Shared.String_Elements.Table (Current);
            Debug_Output (Get_Name_String (Element.Display_Value));
            Current := Element.Next;
         end loop;

         Debug_Decrease_Indent ("end Source_Dirs.");
      end if;
   end Show_Source_Dirs;

   ---------------------------
   -- Process_Naming_Scheme --
   ---------------------------

   procedure Process_Naming_Scheme
     (Tree         : Project_Tree_Ref;
      Root_Project : Project_Id;
      Node_Tree    : GPR.Tree.Project_Node_Tree_Ref;
      Flags        : Processing_Flags)
   is

      procedure Check
        (Project          : Project_Id;
         In_Aggregate_Lib : Boolean;
         Data             : in out Tree_Processing_Data);
      --  Process the naming scheme for a single project

      procedure Recursive_Check
        (Project  : Project_Id;
         Prj_Tree : Project_Tree_Ref;
         Context  : Project_Context;
         Data     : in out Tree_Processing_Data);
      --  Check_Naming_Scheme for the project

      -----------
      -- Check --
      -----------

      procedure Check
        (Project          : Project_Id;
         In_Aggregate_Lib : Boolean;
         Data             : in out Tree_Processing_Data)
      is
         procedure Check_Aggregated;
         --  Check aggregated projects which should not be externally built

         ----------------------
         -- Check_Aggregated --
         ----------------------

         procedure Check_Aggregated is
            L : Aggregated_Project_List;

         begin
            --  Check that aggregated projects are neither externally built nor
            --  abstract projects.

            L := Project.Aggregated_Projects;
            while L /= null loop
               declare
                  Var : constant GPR.Variable_Value :=
                          GPR.Util.Value_Of
                            (Snames.Name_Externally_Built,
                             L.Project.Decl.Attributes,
                             Data.Tree.Shared);
               begin
                  if not Var.Default
                    and then To_Lower (Get_Name_String (Var.Value)) = "true"
                  then
                     Error_Msg_Name_1 := L.Project.Display_Name;
                     Error_Msg
                       (Data.Flags,
                        "cannot aggregate externally built project %%",
                        Var.Location, Project);
                  end if;

                  if L.Project.Qualifier = Abstract_Project then
                     Error_Msg_Name_1 := L.Project.Display_Name;
                        Error_Msg
                          (Data.Flags,
                           "cannot aggregate abstract project %%",
                           No_Location, Project);
                  end if;
               end;

               L := L.Next;
            end loop;
         end Check_Aggregated;

         --  Local Variables

         Shared   : constant Shared_Project_Tree_Data_Access :=
                      Data.Tree.Shared;
         Prj_Data : Project_Processing_Data;

         No_Sources : Boolean := False;

      --  Start of processing for Check

      begin
         Debug_Increase_Indent ("check", Project.Name);

         Initialize (Prj_Data, Project);

         Check_If_Externally_Built (Project, Data);

         case Project.Qualifier is
            when Aggregate | Aggregate_Library =>
               Get_Object_Directory (Project, Data);
               Check_Aggregated;

               if Project.Object_Directory = No_Path_Information then
                  Project.Object_Directory := Project.Directory;
               end if;

            when others =>
               Get_Directories (Project, Data, No_Sources);
               Check_Programming_Languages (Project, Data);

               if Current_Verbosity = High then
                  Show_Source_Dirs (Project, Shared);
               end if;

               if Project.Qualifier = Abstract_Project then
                  Check_Abstract_Project (Project, Data);
               end if;
         end case;

         --  Check configuration.

         Check_Configuration (Project, Data);

         if not Data.Flags.Check_Configuration_Only then
            if Project.Qualifier /= Aggregate then
               --  Externally built projects are allowed to be library projects
               --  even when they have no sources.

               No_Sources := No_Sources and then not Project.Externally_Built;

               --  A project with no sources cannot be a library project

               if No_Sources and then Project.Qualifier = Library then
                  Error_Msg
                    (Data.Flags,
                     "a project with no sources cannot be a library project",
                     Project.Location, Project);

               else
                  Check_Library_Attributes (Project, No_Sources, Data);
               end if;

               Check_Package_Naming (Project, Data);

               --  An aggregate library has no source, no need to look for them

               if Project.Qualifier /= Aggregate_Library then
                  Look_For_Sources (Prj_Data, Data);
               end if;

               Check_Interfaces (Project, Data);

               --  If this library is part of an aggregated library don't check
               --  it as it has no sources by itself and so interface won't be
               --  found.

               if Project.Library and not In_Aggregate_Lib then
                  Check_Stand_Alone_Library (Project, Data);
               end if;

               Get_Mains (Project, Data);
            end if;

            Free (Prj_Data);
         end if;

         Debug_Decrease_Indent ("done check");

      end Check;

      ---------------------
      -- Recursive_Check --
      ---------------------

      procedure Recursive_Check
        (Project  : Project_Id;
         Prj_Tree : Project_Tree_Ref;
         Context  : Project_Context;
         Data     : in out Tree_Processing_Data)
      is
      begin
         if Current_Verbosity = High then
            Debug_Increase_Indent
              ("Processing_Naming_Scheme for project", Project.Name);
         end if;

         Data.Tree := Prj_Tree;
         Data.In_Aggregate_Lib := Context.In_Aggregate_Lib;

         Check (Project, Context.In_Aggregate_Lib, Data);

         if Current_Verbosity = High then
            Debug_Decrease_Indent ("done Processing_Naming_Scheme");
         end if;
      end Recursive_Check;

      procedure Check_All_Projects is new For_Every_Project_Imported_Context
        (Tree_Processing_Data, Recursive_Check);
      --  Comment required???

      --  Local Variables

      Data : Tree_Processing_Data;

   --  Start of processing for Process_Naming_Scheme

   begin
      Lib_Data_Table.Init;
      Initialize (Data, Tree => Tree, Node_Tree => Node_Tree, Flags => Flags);
      Check_All_Projects (Root_Project, Tree, Data, Imported_First => True);
      Free (Data);

      --  Adjust language configs for projects that are extended

      declare
         List : Project_List;
         Proj : Project_Id;
         Exte : Project_Id;
         Lang : Language_Ptr;
         Elng : Language_Ptr;

      begin
         List := Tree.Projects;
         while List /= null loop
            Proj := List.Project;

            Exte := Proj;
            while Exte.Extended_By /= No_Project loop
               Exte := Exte.Extended_By;
            end loop;

            if Exte /= Proj then
               Lang := Proj.Languages;

               if Lang /= No_Language_Index then
                  loop
                     Elng := Get_Language_From_Name
                       (Exte, Get_Name_String (Lang.Name));
                     exit when Elng /= No_Language_Index;
                     Exte := Exte.Extends;
                  end loop;

                  if Elng /= Lang then
                     Lang.Config := Elng.Config;
                  end if;
               end if;
            end if;

            List := List.Next;
         end loop;
      end;
   end Process_Naming_Scheme;

end GPR.Nmsc;
