------------------------------------------------------------------------------
--                                                                          --
--                           GPR PROJECT MANAGER                            --
--                                                                          --
--                     Copyright (C) 2001-2023, AdaCore                     --
--                                                                          --
-- 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/>.                                          --
--                                                                          --
------------------------------------------------------------------------------

--  The following package declares the data types for GNAT project.
--  These data types may be used by GNAT Project-aware tools.

--  Children of this package implement various services on these data types

with Ada.Containers.Hashed_Maps;
with Ada.Containers.Indefinite_Ordered_Sets;
with Ada.Containers.Ordered_Sets;

with GNAT.Dynamic_HTables; use GNAT.Dynamic_HTables;
with GNAT.Dynamic_Tables;

with GNAT.OS_Lib; use GNAT.OS_Lib;

with System.Storage_Elements;

package GPR is

   EOF : constant Character := ASCII.SUB;
   --  The character SUB (16#1A#) is used in DOS and other systems derived
   --  from DOS (XP, NT etc) to signal the end of a text file. Internally all
   --  source files are ended by an EOF character, even on Unix systems. An EOF
   --  character acts as the end of file only as the last character of a source
   --  buffer, in any other position, it is treated as a blank if it appears
   --  between tokens, and as an illegal character otherwise. This makes
   --  life easier dealing with files that originated from DOS, including
   --  concatenated files with interspersed EOF characters.

   Shared_Libgcc : constant String := "-shared-libgcc";
   Static_Libgcc : constant String := "-static-libgcc";
   Dash_Shared   : constant String := "-shared";
   Dash_Static   : constant String := "-static";
   Dash_Lgnat    : constant String := "-lgnat";
   Dash_Lgnarl   : constant String := "-lgnarl";

   On_Windows : constant Boolean := Directory_Separator = '\';
   --  True when on Windows

   -----------
   -- Types --
   -----------

   -------------------------------
   -- General Use Integer Types --
   -------------------------------

   type Int is range -2 ** 31 .. +2 ** 31 - 1;
   --  Signed 32-bit integer

   subtype Nat is Int range 0 .. Int'Last;
   --  Non-negative Int values

   subtype Pos is Int range 1 .. Int'Last;
   --  Positive Int values

   type Word is mod 2 ** 32;
   --  Unsigned 32-bit integer

   type size_t is mod 2 ** Standard'Address_Size;

   subtype Upper_Half_Character is
     Character range Character'Val (16#80#) .. Character'Val (16#FF#);
   --  8-bit Characters with the upper bit set

   subtype Graphic_Character is Character range ' ' .. '~';
   --  Graphic characters, as defined in Ada Reference Manual

   subtype Line_Terminator is Character range ASCII.LF .. ASCII.CR;
   --  Line terminator characters (LF, VT, FF, CR)

   type Source_Ptr is new Int;
   --  Type used to represent a source location, which is a subscript of a
   --  character in the source buffer. As noted above, different source buffers
   --  have different ranges, so it is possible to tell from a Source_Ptr value
   --  which source it refers to. Note that negative numbers are allowed to
   --  accommodate the following special values.

   No_Location : constant Source_Ptr := -1;
   --  Value used to indicate no source position set in a node. A test for a
   --  Source_Ptr value being > No_Location is the approved way to test for a
   --  standard value that does not include No_Location or any of the following
   --  special definitions. One important use of No_Location is to label
   --  generated nodes that we don't want the debugger to see in normal mode
   --  (very often we conditionalize so that we set No_Location in normal mode
   --  and the corresponding source line in -gnatD mode).

   First_Source_Ptr : constant Source_Ptr := 0;
   --  Starting source pointer index value for first source program

   type Source_File_Index is new Int range -1 .. Int'Last;
   --  Type used to index the source file table (see package GPR.Sinput)

   No_Source_File : constant Source_File_Index := 0;
   --  Value used to indicate no source file present

   -----------
   -- Nodes --
   -----------
   type Node_Id is range 0 .. 99_999_999;
   --  Type used to identify nodes in the tree

   Empty_Node : constant Node_Id := 0;
   --  Used to indicate null node. A node is actually allocated with this Id
   --  value, so that Nkind (Empty) = N_Empty. Note that Node_Low_Bound is
   --  zero, so Empty = No_List = zero.

   Error_Node : constant Node_Id := 1;
   --  Used to indicate an error in the source program. A node is actually
   --  allocated with this Id value, so that Nkind (Error) = N_Error.

   First_Node_Id  : constant Node_Id := 0;
   --  Subscript of first allocated node. Note that Empty and Error are both
   --  allocated nodes, whose Nkind fields can be accessed without error.

   Unrecoverable_Error : exception;

   -------------------
   -- Project nodes --
   -------------------

   Project_Nodes_Initial   : constant := 1_000;
   Project_Nodes_Increment : constant := 100;
   --  Allocation parameters for initializing and extending number
   --  of nodes in table Tree_Private_Part.Project_Nodes

   Project_Node_Low_Bound  : constant := 0;
   Project_Node_High_Bound : constant := 099_999_999;
   --  Range of values for project node id's (in practice infinite)

   type Project_Node_Id is range
     Project_Node_Low_Bound .. Project_Node_High_Bound;
   --  The index of table Tree_Private_Part.Project_Nodes

   Empty_Project_Node : constant Project_Node_Id := Project_Node_Low_Bound;
   --  Designates no node in table Project_Nodes

   First_Project_Node_Id : constant Project_Node_Id :=
                                      Project_Node_Low_Bound + 1;

   type Response_File_Format is
     (None,
      GNU,
      Object_List,
      Option_List,
      GCC,
      GCC_GNU,
      GCC_Object_List,
      GCC_Option_List);
   --  The format of the different response files

   ------------
   -- Stamps --
   ------------

   package Stamps is

      -----------------------------------
      -- Representation of Time Stamps --
      -----------------------------------

      --  All compiled units are marked with a time stamp which is derived from
      --  the source file (we assume that the host system has the concept of a
      --  file time stamp which is modified when a file is modified). These
      --  time stamps are used to ensure consistency of the set of units that
      --  constitutes a library. Time stamps are 14-character strings with
      --  with the following format:

      --     YYYYMMDDHHMMSS

      --       YYYY   year
      --       MM     month (2 digits 01-12)
      --       DD     day (2 digits 01-31)
      --       HH     hour (2 digits 00-23)
      --       MM     minutes (2 digits 00-59)
      --       SS     seconds (2 digits 00-59)

      --  In the case of Unix systems (and other systems which keep the time in
      --  GMT), the time stamp is the GMT time of the file, not the local time.
      --  This solves problems in using libraries across networks with clients
      --  spread across multiple time-zones.

      Time_Stamp_Length : constant := 14;
      --  Length of time stamp value

      subtype Time_Stamp_Index is Natural range 1 .. Time_Stamp_Length;
      type Time_Stamp_Type is new String (Time_Stamp_Index);
      --  Type used to represent time stamp

      Empty_Time_Stamp : constant Time_Stamp_Type := (others => ' ');
      --  Value representing an empty or missing time stamp. Looks less than
      --  any real time stamp if two time stamps are compared. Note that
      --  although this is not private, clients should not rely on the exact
      --  way in which this string is represented, and instead should use the
      --  subprograms below.
      --  Note : the Empty_Time_Stamp value less than any non-empty time stamp
      --  value.

      Dummy_Time_Stamp : constant Time_Stamp_Type := (others => '0');
      --  This is used for dummy time stamp values used in the D lines for
      --  non-existent files, and is intended to be an impossible value.

   end Stamps;

   use Stamps;

   --------------------
   -- Default Output --
   --------------------

   type Section_Type is (Setup, Compile, Build_Libraries, Bind, Link);
   --  Different sections in the default output, when switches -q and -v are
   --  not used.

   procedure Set (Section : Section_Type);
   --  Indicate that the section header does not need to be output again.
   --  This is used by gprbind and gprlib to avoid display the section header
   --  again.

   procedure Display
     (Section  : Section_Type;
      Command  : String;
      Argument : String);
   --  Display a command in the standard output. Display first the section
   --  header if it has not been already displayed.

   --------------------

   type Name_Id is range 0 .. 99_999_999;
   No_Name : constant Name_Id := 0;
   Error_Name : constant Name_Id := 1;

   First_Name_Id : constant Name_Id := 2;
   --  Subscript of first entry in names table

   package Name_Id_Set is new Ada.Containers.Ordered_Sets (Name_Id);

   type Unit_Name_Type is new Name_Id;
   --  Unit names are stored in the names table and this type is used to
   --  indicate that a Name_Id value is being used to hold a unit name,
   --  which terminates in %b for a body or %s for a spec.

   No_Unit_Name : constant Unit_Name_Type := Unit_Name_Type (No_Name);
   --  Constant used to indicate no file name present

   Error_Unit_Name : constant Unit_Name_Type := Unit_Name_Type (Error_Name);
   --  The special Unit_Name_Type value Error_Unit_Name is used to indicate
   --  a unit name where some previous processing has found an error.

   package String_Sets is new Ada.Containers.Indefinite_Ordered_Sets (String);

   ------------------------------
   -- File and Path Name Types --
   ------------------------------

   type File_Name_Type is new Name_Id;
   --  File names are stored in the names table and this type is used to
   --  indicate that a Name_Id value is being used to hold a simple file
   --  name (which does not include any directory information).

   No_File : constant File_Name_Type := File_Name_Type (No_Name);
   --  Constant used to indicate no file is present (this is used for
   --  example when a search for a file indicates that no file of the
   --  name exists).

   Error_File_Name : constant File_Name_Type := File_Name_Type (Error_Name);
   --  The special File_Name_Type value Error_File_Name is used to indicate
   --  a unit name where some previous processing has found an error.

   type Path_Name_Type is new Name_Id;
   --  Path names are stored in the names table and this type is used to
   --  indicate that a Name_Id value is being used to hold a path name (that
   --  may contain directory information).

   No_Path : constant Path_Name_Type := Path_Name_Type (No_Name);
   --  Constant used to indicate no path name is present

   File_Attributes_Size : constant Natural := 32;
   type File_Attributes is
     array (1 .. File_Attributes_Size)
     of System.Storage_Elements.Storage_Element;
   for File_Attributes'Alignment use Standard'Maximum_Alignment;
   --  A cache for various attributes for a file (length, accessibility,...)
   --  This must be initialized to Unknown_Attributes prior to the first call.

   Unknown_Attributes : File_Attributes := (others => 0);
   --  A cache for various attributes for a file (length, accessibility,...)
   --  Will be initialized properly at elaboration (for efficiency later on,
   --  avoid function calls every time we want to reset the attributes) prior
   --  to the first usage. We cannot make it constant since the compiler may
   --  put it in a read-only section.

   Ada_Include_Path          : constant String := "ADA_INCLUDE_PATH";
   Ada_Objects_Path          : constant String := "ADA_OBJECTS_PATH";
   Project_Include_Path_File : constant String := "ADA_PRJ_INCLUDE_FILE";
   Project_Objects_Path_File : constant String := "ADA_PRJ_OBJECTS_FILE";

   procedure Add_Restricted_Language (Name : String);
   --  Call by gprbuild for each language specified by switch
   --  --restricted-to-languages=.

   procedure Remove_All_Restricted_Languages;
   --  Call by gprbuild in CodePeer mode to ignore switches
   --  --restricted-to-languages=.

   function Is_Allowed_Language (Name : Name_Id) return Boolean;
   --  Returns True if --restricted-to-languages= is not used or if Name
   --  is one of the restricted languages.

   function Languages_Are_Restricted return Boolean;
   --  Returns True iff the list of restricted languages is not empty.

   All_Other_Names : constant Name_Id := Name_Id'Last;
   --  Name used to replace others as an index of an associative array
   --  attribute in situations where this is allowed.

   Subdirs : String_Access;
   --  The value after the equal sign in switch --subdirs=...
   --  Contains the relative subdirectory.

   Src_Subdirs : String_Access;
   --  The value after the equal sign in switch --src-subdirs=...
   --  Contains the relative subdirectory.

   Build_Tree_Dir : String_Access;
   --  A root directory for building out-of-tree projects. All relative object
   --  directories will be rooted at this location.

   Root_Dir : String_Access;
   --  When using out-of-tree build we need to keep information about the root
   --  directory of artifacts to properly relocate them. Note that the root
   --  directory is not necessarily the directory of the main project.

   Getrusage : String_Access;
   --  Print getrusage call output to file

   type Library_Support is (None, Static_Only, Full);
   --  Support for Library Project File.
   --  - None: Library Project Files are not supported at all
   --  - Static_Only: Library Project Files are only supported for static
   --    libraries.
   --  - Full: Library Project Files are supported for static and dynamic
   --    (shared) libraries.

   type Yes_No_Unknown is (Yes, No, Unknown);
   --  Tri-state to decide if -lgnarl is needed when linking

   type Attribute_Default_Value is
     (Read_Only_Value,          --  For read only attributes (Name,Project_Dir)
      Empty_Value,              --  Empty string or empty string list
      Dot_Value,                --  "." or (".")
      Object_Dir_Value,         --  'Object_Dir
      Target_Value,             --  'Target (special rules)
      Runtime_Value,            --  'Runtime (special rules)
      Canonical_Target_Value);  --  'Canonical_Target (special rules)
   --  Describe the default values of attributes that are referenced but not
   --  declared.

   pragma Warnings (Off);
   type Project_Qualifier is
     (Unspecified,

      --  The following clash with Standard is OK, and justified by the context
      --  which really wants to use the same set of qualifiers.

      Standard,

      Library,
      Configuration,
      Abstract_Project,
      Aggregate,
      Aggregate_Library);
   pragma Warnings (On);
   --  Qualifiers that can prefix the reserved word "project" in a project
   --  file:
   --    Standard:             standard project ...
   --    Library:              library project is ...
   --    Abstract_Project:     abstract project is
   --    Aggregate:            aggregate project is
   --    Aggregate_Library:    aggregate library project is ...
   --    Configuration:        configuration project is ...

   subtype Aggregate_Project is
     Project_Qualifier range Aggregate .. Aggregate_Library;

   All_Packages : constant String_List_Access;
   --  Default value of parameter Packages of procedures Parse, in Prj.Pars and
   --  Prj.Part, indicating that all packages should be checked.

   type Project_Tree_Data;
   type Project_Tree_Ref is access all Project_Tree_Data;
   --  Reference to a project tree. Several project trees may exist in memory
   --  at the same time.

   No_Project_Tree : constant Project_Tree_Ref;

   procedure Free (Tree : in out Project_Tree_Ref);
   --  Free memory associated with the tree

   Config_Project_File_Extension : String := ".cgpr";
   Project_File_Extension : String := ".gpr";
   --  The standard config and user project file name extensions. They are not
   --  constants, because Canonical_Case_File_Name is called on these variables
   --  in the body of Prj.

   GNAT_And_Space : constant String := "GNAT ";

   function Empty_File   return File_Name_Type with Inline_Always;
   function Empty_String return Name_Id        with Inline_Always;
   --  Return the id for an empty string ""

   function Dot_String return Name_Id with Inline_Always;
   --  Return the id for "."

   type Path_Information is record
      Name         : Path_Name_Type := No_Path;
      Display_Name : Path_Name_Type := No_Path;
   end record;
   --  Directory names always end with a directory separator

   No_Path_Information : constant Path_Information := (No_Path, No_Path);

   type Project_Data;
   type Project_Id is access all Project_Data;
   No_Project : constant Project_Id := null;
   --  Id of a Project File

   type String_List_Id is new Nat;
   Nil_String : constant String_List_Id := 0;
   type String_Element is record
      Value         : Name_Id        := No_Name;
      Index         : Int            := 0;
      Display_Value : Name_Id        := No_Name;
      Location      : Source_Ptr     := No_Location;
      Next          : String_List_Id := Nil_String;
   end record;
   --  To hold values for string list variables and array elements.

   package String_Element_Table is new GNAT.Dynamic_Tables
     (Table_Component_Type => String_Element,
      Table_Index_Type     => String_List_Id,
      Table_Low_Bound      => 1,
      Table_Initial        => 200,
      Table_Increment      => 100);
   --  The table for string elements in string lists

   type Variable_Kind is (Undefined, List, Single);
   --  Different kinds of variables

   subtype Defined_Variable_Kind is Variable_Kind range List .. Single;
   --  The defined kinds of variables

   Ignored : constant Variable_Kind;
   --  Used to indicate that a package declaration must be ignored while
   --  processing the project tree (unknown package name).

   type Variable_Value (Kind : Variable_Kind := Undefined) is record
      Project              : Project_Id := No_Project;
      Location             : Source_Ptr := No_Location;
      String_Type          : Project_Node_Id := Empty_Project_Node;
      Default              : Boolean    := False;
      From_Implicit_Target : Boolean := False;
      case Kind is
         when Undefined =>
            null;
         when List =>
            Values : String_List_Id := Nil_String;
            Concat : Boolean := False;
         when Single =>
            Value : Name_Id := No_Name;
            Index : Int     := 0;
      end case;
   end record;
   --  Values for variables and array elements. Default is True if the
   --  current value is the default one for the variable. String_Type is
   --  Empty_Project_Node, except for typed variables where it designates
   --  the string type node.
   --
   --  From_Implicit_Target is only changed to True when evaluating
   --  an expression that depends on 'Target reference, and the target is not
   --  explicitly declared in corresponding project. In such case the 'Target
   --  is still evaluated to normalized hostname, however at configuration
   --  phase it is not possible to distinguish this case from real explicit
   --  native target specification. So if in root project we have
   --     for Target use Imported_Project'Target;
   --  and Imported_Project has no explicit target declaration it is otherwise
   --  not possible to understand that target fallback if needed.

   Nil_Variable_Value : constant Variable_Value;
   --  Value of a non existing variable or array element

   type Variable_Id is new Nat;
   No_Variable : constant Variable_Id := 0;
   type Variable is record
      Next  : Variable_Id := No_Variable;
      Name  : Name_Id;
      Value : Variable_Value;
   end record;
   --  To hold the list of variables in a project file and in packages

   package Variable_Element_Table is new GNAT.Dynamic_Tables
     (Table_Component_Type => Variable,
      Table_Index_Type     => Variable_Id,
      Table_Low_Bound      => 1,
      Table_Initial        => 200,
      Table_Increment      => 100);
   --  The table of variable in list of variables

   type Array_Element_Id is new Nat;
   No_Array_Element : constant Array_Element_Id := 0;
   type Array_Element is record
      Index                : Name_Id;
      Restricted           : Boolean          := False;
      Src_Index            : Int              := 0;
      Index_Case_Sensitive : Boolean          := True;
      Value                : Variable_Value;
      Next                 : Array_Element_Id := No_Array_Element;
   end record;
   --  Each Array_Element represents an array element and is linked (Next)
   --  to the next array element, if any, in the array.

   package Array_Element_Table is new GNAT.Dynamic_Tables
     (Table_Component_Type => Array_Element,
      Table_Index_Type     => Array_Element_Id,
      Table_Low_Bound      => 1,
      Table_Initial        => 200,
      Table_Increment      => 100);
   --  The table that contains all array elements

   type Array_Id is new Nat;
   No_Array : constant Array_Id := 0;
   type Array_Data is record
      Name     : Name_Id          := No_Name;
      Location : Source_Ptr       := No_Location;
      Value    : Array_Element_Id := No_Array_Element;
      Next     : Array_Id         := No_Array;
   end record;
   --  Each Array_Data value represents an array.
   --  Value is the id of the first element.
   --  Next is the id of the next array in the project file or package.

   package Array_Table is new GNAT.Dynamic_Tables
     (Table_Component_Type => Array_Data,
      Table_Index_Type     => Array_Id,
      Table_Low_Bound      => 1,
      Table_Initial        => 200,
      Table_Increment      => 100);
   --  The table that contains all arrays

   type Package_Id is new Nat;
   No_Package : constant Package_Id := 0;
   type Declarations is record
      Variables  : Variable_Id := No_Variable;
      Attributes : Variable_Id := No_Variable;
      Arrays     : Array_Id    := No_Array;
      Packages   : Package_Id  := No_Package;
   end record;
   --  Contains the declarations (variables, single and array attributes,
   --  packages) for a project or a package in a project.

   No_Declarations : constant Declarations :=
                       (Variables  => No_Variable,
                        Attributes => No_Variable,
                        Arrays     => No_Array,
                        Packages   => No_Package);
   --  Default value of Declarations: used if there are no declarations

   type Package_Element is record
      Name   : Name_Id      := No_Name;
      Decl   : Declarations := No_Declarations;
      Parent : Package_Id   := No_Package;
      Next   : Package_Id   := No_Package;
   end record;
   --  A package (includes declarations that may include other packages)

   package Package_Table is new GNAT.Dynamic_Tables
     (Table_Component_Type => Package_Element,
      Table_Index_Type     => Package_Id,
      Table_Low_Bound      => 1,
      Table_Initial        => 100,
      Table_Increment      => 100);
   --  The table that contains all packages

   type Language_Data;
   type Language_Ptr is access all Language_Data;
   --  Index of language data

   No_Language_Index : constant Language_Ptr := null;
   --  Constant indicating that there is no language data

   function Get_Language_From_Name
     (Project : Project_Id;
      Name    : String) return Language_Ptr;
   --  Get a language from a project. This might return null if no such
   --  language exists in the project

   Max_Header_Num : constant := 6150;
   type Header_Num is range 0 .. Max_Header_Num;
   --  Size for hash table below. The upper bound is an arbitrary value, the
   --  value here was chosen after testing to determine a good compromise
   --  between speed of access and memory usage.

   function Hash (Name : Name_Id)        return Header_Num;
   function Hash (Name : File_Name_Type) return Header_Num;
   function Hash (Name : Path_Name_Type) return Header_Num;
   function Hash (Project : Project_Id)  return Header_Num;
   --  Used for computing hash values for names put into hash tables

   type Language_Kind is (File_Based, Unit_Based);
   --  Type for the kind of language. All languages are file based, except Ada
   --  which is unit based.

   --  Type of dependency to be checked

   type Dependency_File_Kind is
     (None,
      --  There is no dependency file, the source must always be recompiled

      Makefile,
      --  The dependency file is a Makefile fragment indicating all the files
      --  the source depends on. If the object file or the dependency file is
      --  more recent than any of these files, the source must be recompiled.

      ALI_File,
      --  The dependency file is an ALI file and the source must be recompiled
      --  if the object or ALI file is more recent than any of the sources
      --  listed in the D lines.

      ALI_Closure);
      --  The dependency file is an ALI file and the source must be recompiled
      --  if the object or ALI file is more recent than any source in the full
      --  closure.

   subtype ALI_Dependency is
     Dependency_File_Kind range ALI_File .. ALI_Closure;

   Makefile_Dependency_Suffix : constant String := ".d";
   ALI_Dependency_Suffix      : constant String := ".ali";
   Switches_Dependency_Suffix : constant String := ".cswi";

   Binder_Exchange_Suffix : constant String := ".bexch";
   --  Suffix for binder exchange files

   Library_Exchange_Suffix : constant String := ".lexch";
   --  Suffix for library exchange files

   type Name_List_Index is new Nat;
   No_Name_List : constant Name_List_Index := 0;

   type Name_Node is record
      Name : Name_Id         := No_Name;
      Next : Name_List_Index := No_Name_List;
   end record;

   package Name_List_Table is new GNAT.Dynamic_Tables
     (Table_Component_Type => Name_Node,
      Table_Index_Type     => Name_List_Index,
      Table_Low_Bound      => 1,
      Table_Initial        => 10,
      Table_Increment      => 100);
   --  The table for lists of names

   function Length
     (Table : Name_List_Table.Instance;
      List  : Name_List_Index) return Natural;
   --  Return the number of elements in specified list

   type Number_List_Index is new Nat;
   No_Number_List : constant Number_List_Index := 0;

   type Number_Node is record
      Number : Natural           := 0;
      Next   : Number_List_Index := No_Number_List;
   end record;

   package Number_List_Table is new GNAT.Dynamic_Tables
     (Table_Component_Type => Number_Node,
      Table_Index_Type     => Number_List_Index,
      Table_Low_Bound      => 1,
      Table_Initial        => 10,
      Table_Increment      => 100);
   --  The table for lists of numbers

   package Mapping_Files_Htable is new Simple_HTable
     (Header_Num => Header_Num,
      Element    => Path_Name_Type,
      No_Element => No_Path,
      Key        => Path_Name_Type,
      Hash       => Hash,
      Equal      => "=");
   --  A hash table to store the mapping files that are not used

   --  The following record ???

   type Casing_Type is (

      All_Upper_Case,
      --  All letters are upper case

      All_Lower_Case,
      --  All letters are lower case

      Mixed_Case,
      --  The initial letter, and any letters after underlines are upper case.
      --  All other letters are lower case

      Unknown
      --  Used if an identifier does not distinguish between the above cases,
      --  (e.g. X, Y_3, M4, A_B, or if it is inconsistent ABC_def).
   );

   subtype Known_Casing is Casing_Type range All_Upper_Case .. Mixed_Case;
   --  Exclude Unknown casing

   type Lang_Naming_Data is record
      Dot_Replacement : File_Name_Type := No_File;
      --  The string to replace '.' in the source file name (for Ada)

      Casing : Casing_Type := All_Lower_Case;
      --  The casing of the source file name (for Ada)

      Separate_Suffix : File_Name_Type := No_File;
      --  String to append to unit name for source file name of an Ada subunit

      Spec_Suffix : File_Name_Type := No_File;
      --  The string to append to the unit name for the
      --  source file name of a spec.

      Body_Suffix : File_Name_Type := No_File;
      --  The string to append to the unit name for the
      --  source file name of a body.
   end record;

   No_Lang_Naming_Data : constant Lang_Naming_Data := (others => <>);

   function Is_Standard_GNAT_Naming (Naming : Lang_Naming_Data) return Boolean;
   --  True if the naming scheme is GNAT's default naming scheme. This
   --  is to take into account shortened names like "Ada." (a-), "System." (s-)
   --  and so on.

   type Source_Data;
   type Source_Id is access all Source_Data;

   function Is_Compilable (Source : Source_Id) return Boolean;
   pragma Inline (Is_Compilable);
   --  Return True if we know how to compile Source (i.e. if a compiler is
   --  defined). This doesn't indicate whether the source should be compiled.

   function Object_To_Global_Archive (Source : Source_Id) return Boolean;
   pragma Inline (Object_To_Global_Archive);
   --  Return True if the object file should be put in the global archive.
   --  This is for Ada, when only the closure of a main needs to be
   --  (re)compiled.

   function Other_Part (Source : Source_Id) return Source_Id;
   pragma Inline (Other_Part);
   --  Source ID for the other part, if any: for a spec, returns its body;
   --  for a body, returns its spec.

   No_Source : constant Source_Id := null;

   --  The following record describes the configuration of a language

   type Language_Config is record
      Kind : Language_Kind := File_Based;
      --  Kind of language. Most languages are file based. A few, such as Ada,
      --  are unit based.

      Naming_Data : Lang_Naming_Data;
      --  The naming data for the languages (prefixes, etc.)

      Include_Compatible_Languages : Name_List_Index := No_Name_List;
      --  List of languages that are "include compatible" with this language. A
      --  language B (for example "C") is "include compatible" with a language
      --  A (for example "C++") if it is expected that sources of language A
      --  may "include" header files from language B.

      Compiler_Driver : File_Name_Type := No_File;
      --  The name of the executable for the compiler of the language

      Compiler_Driver_Path : String_Access := null;
      --  The path name of the executable for the compiler of the language

      Compiler_Leading_Required_Switches : Name_List_Index := No_Name_List;
      --  The list of initial switches that are required as a minimum to invoke
      --  the compiler driver.

      Compiler_Trailing_Required_Switches : Name_List_Index := No_Name_List;
      --  The list of final switches that are required as a minimum to invoke
      --  the compiler driver.

      Multi_Unit_Switches : Name_List_Index := No_Name_List;
      --  The switch(es) to indicate the index of a unit in a multi-source file

      Multi_Unit_Object_Separator : Character := ' ';
      --  The string separating the base name of a source from the index of the
      --  unit in a multi-source file, in the object file name.

      Source_File_Switches : Name_List_Index := No_Name_List;
      --  Optional switches to be put before the source file. The source file
      --  path name is appended to the last switch in the list.
      --  Example: ("-i", "");

      Object_File_Suffix : Name_Id := No_Name;
      --  Optional alternate object file suffix

      Object_File_Switches : Name_List_Index := No_Name_List;
      --  Optional object file switches. When this is defined, the switches
      --  are used to specify the object file. The object file name is appended
      --  to the last switch in the list. Example: ("-o", "").

      Object_Path_Switches : Name_List_Index := No_Name_List;
      --  List of switches to specify to the compiler the path name of a
      --  temporary file containing the list of object directories in the
      --  correct order.

      Compilation_PIC_Option : Name_List_Index := No_Name_List;
      --  The option(s) to compile a source in Position Independent Code for
      --  shared libraries. Specified in the configuration. When not specified,
      --  there is no need for such switch.

      Object_Generated : Boolean := True;
      --  False if no object file is generated

      Objects_Linked : Boolean := True;
      --  False if object files are not use to link executables and build
      --  libraries.

      Runtime_Dir : Name_Id := No_Name;
      --  Path name of the runtime directory, if any

      Runtime_Library_Dirs : Name_List_Index := No_Name_List;
      --  Path names of the runtime library directories, if any

      Runtime_Source_Dirs : Name_List_Index := No_Name_List;
      --  Path names of the runtime source directories, if any

      Runtime_Library_Version : Name_Id := No_Name;
      --  Value of the library version

      Mapping_File_Switches : Name_List_Index := No_Name_List;
      --  The option(s) to provide a mapping file to the compiler. Specified in
      --  the configuration. When value is No_Name_List, there is no mapping
      --  file.

      Mapping_Spec_Suffix : File_Name_Type := No_File;
      --  Placeholder representing the spec suffix in a mapping file

      Mapping_Body_Suffix : File_Name_Type := No_File;
      --  Placeholder representing the body suffix in a mapping file

      Config_File_Switches : Name_List_Index := No_Name_List;
      --  The option(s) to provide a config file to the compiler. Specified in
      --  the configuration. If value is No_Name_List there is no config file.

      Dependency_Kind : Dependency_File_Kind := None;
      --  The kind of dependency to be checked: none, Makefile fragment or
      --  ALI file (for Ada).

      Dependency_Option : Name_List_Index := No_Name_List;
      --  The option(s) to be used to create the dependency file. When value is
      --  No_Name_List, there is not such option(s).

      Compute_Dependency : Name_List_Index := No_Name_List;
      --  Hold the value of attribute Dependency_Driver, if declared for the
      --  language.

      Include_Option : Name_List_Index := No_Name_List;
      --  Hold the value of attribute Include_Switches, if declared for the
      --  language.

      Include_Path : Name_Id := No_Name;
      --  Name of environment variable declared by attribute Include_Path for
      --  the language.

      Include_Switches_Via_Spec : Name_List_Index := No_Name_List;
      --  Indicate the name of the underlying compiler and the switch to
      --  specify an included source directory.
      --  Used to invoke a GNU compiler with switch -specs, to avoid long
      --  command lines.

      Include_Path_File : Name_Id := No_Name;
      --  Name of environment variable declared by attribute Include_Path_File
      --  for the language.

      Only_Dirs_With_Sources : Boolean := False;
      --  When True, only the directories that contain sources of the language
      --  are used as included directories when compiling.

      Objects_Path : Name_Id := No_Name;
      --  Name of environment variable declared by attribute Objects_Path for
      --  the language.

      Objects_Path_File : Name_Id := No_Name;
      --  Name of environment variable declared by attribute Objects_Path_File
      --  for the language.

      Config_Body : Name_Id := No_Name;
      --  The template for a pragma Source_File_Name(_Project) for a specific
      --  file name of a body.

      Config_Body_Index : Name_Id := No_Name;
      --  The template for a pragma Source_File_Name(_Project) for a specific
      --  file name of a body in a multi-source file.

      Config_Body_Pattern : Name_Id := No_Name;
      --  The template for a pragma Source_File_Name(_Project) for a naming
      --  body pattern.

      Config_Spec : Name_Id := No_Name;
      --  The template for a pragma Source_File_Name(_Project) for a specific
      --  file name of a spec.

      Config_Spec_Index : Name_Id := No_Name;
      --  The template for a pragma Source_File_Name(_Project) for a specific
      --  file name of a spec in a multi-source file.

      Config_Spec_Pattern : Name_Id := No_Name;
      --  The template for a pragma Source_File_Name(_Project) for a naming
      --  spec pattern.

      Config_File_Dependency_Support : Boolean := True;
      --  True if dependency of the source files from config file is supported

      Config_File_Unique : Boolean := False;
      --  True if the config file specified to the compiler needs to be unique.
      --  If it is unique, then all config files are concatenated into a temp
      --  config file.

      Binder_Driver : File_Name_Type := No_File;
      --  The name of the binder driver for the language, if any

      Binder_Driver_Path : Path_Name_Type := No_Path;
      --  The path name of the binder driver

      Binder_Required_Switches : Name_List_Index := No_Name_List;
      --  Hold the value of attribute Binder'Required_Switches for the language

      Binder_Prefix : Name_Id := No_Name;
      --  Hold the value of attribute Binder'Prefix for the language

      Toolchain_Version : Name_Id := No_Name;
      --  Hold the value of attribute Toolchain_Version for the language

      Required_Toolchain_Version : Name_Id := No_Name;
      --  Hold the value of attribute Required_Toolchain_Version for the
      --  language.

      Toolchain_Description : Name_Id := No_Name;
      --  Hold the value of attribute Toolchain_Description for the language

      Clean_Object_Artifacts : Name_List_Index := No_Name_List;
      --  List of object artifact extensions to be deleted by gprclean

      Clean_Source_Artifacts : Name_List_Index := No_Name_List;
      --  List of source artifact extensions to be deleted by gprclean

      Resp_File_Format : Response_File_Format := None;
      --  The format of a response file, when compiling with a response file is
      --  supported.

      Resp_File_Options : Name_List_Index := No_Name_List;
      --  The switches, if any, that precede the path name of the response
      --  file in the invocation of the compiler.

   end record;

   No_Language_Config : constant Language_Config := (others => <>);

   type Language_Data is record
      Name : Name_Id := No_Name;
      --  The name of the language in lower case

      Display_Name : Name_Id := No_Name;
      --  The name of the language, as found in attribute Languages

      Config : Language_Config := No_Language_Config;
      --  Configuration of the language

      First_Source : Source_Id := No_Source;
      --  Head of the list of sources of the language in the project

      Mapping_Files : Mapping_Files_Htable.Instance :=
                        Mapping_Files_Htable.Nil;
      --  Hash table containing the mapping of the sources to their path names

      Unconditional_Linking : Boolean := False;
      --  All object files of this language should be linked unconditionally

      Next : Language_Ptr := No_Language_Index;
      --  Next language of the project

   end record;

   No_Language_Data : constant Language_Data := (others => <>);

   type Language_List_Element;
   type Language_List is access all Language_List_Element;
   type Language_List_Element is record
      Language : Language_Ptr := No_Language_Index;
      Next     : Language_List;
   end record;

   type Source_Kind is (Spec, Impl, Sep);
   subtype Spec_Or_Body is Source_Kind range Spec .. Impl;

   --  The following declarations declare a structure used to store the Name
   --  and File and Path names of a unit, with a reference to its GNAT Project
   --  File(s). Some units might have neither Spec nor Impl when they were
   --  created for a "separate".

   type File_Names_Data is array (Spec_Or_Body) of Source_Id;

   type Unit_Data is record
      Name       : Name_Id := No_Name;
      File_Names : File_Names_Data;
   end record;

   type Unit_Index is access all Unit_Data;

   No_Unit_Index : constant Unit_Index := null;
   --  Used to indicate a null entry for no unit

   type Source_Roots;
   type Roots_Access is access Source_Roots;
   type Source_Roots is record
      Root : Source_Id;
      Next : Roots_Access;
   end record;
   --  A list to store the roots associated with a main unit. These are the
   --  files that need to linked along with the main (for instance a C file
   --  corresponding to an Ada file). In general, these are dependencies that
   --  cannot be computed automatically by the builder.

   type Naming_Exception_Type is (No, Yes, Inherited);

   --  Structure to define source data

   type Source_Data is record
      Initialized : Boolean := False;
      --  Set to True when Source_Data is completely initialized

      Project : Project_Id := No_Project;
      --  Project of the source

      Location : Source_Ptr := No_Location;
      --  Location in the project file of the declaration of the source in
      --  package Naming.

      Source_Dir_Rank : Natural := 0;
      --  The rank of the source directory in list declared with attribute
      --  Source_Dirs. Two source files with the same name cannot appears in
      --  different directory with the same rank. That can happen when the
      --  recursive notation <dir>/** is used in attribute Source_Dirs.

      Language : Language_Ptr := No_Language_Index;
      --  Language of the source

      In_Interfaces : Boolean := True;
      --  False when the source is not included in interfaces, when attribute
      --  Interfaces is declared.

      In_Src_Subdir : Boolean := False;
      --  If source is in the --src-subdir direcory it should be In_Interfaces

      Declared_In_Interfaces : Boolean := False;
      --  True when source is declared in attribute Interfaces

      Alternate_Languages : Language_List := null;
      --  List of languages a header file may also be, in addition of language
      --  Language_Name.

      Kind : Source_Kind := Spec;
      --  Kind of the source: spec, body or subunit

      Unit : Unit_Index := No_Unit_Index;
      --  Name of the unit, if language is unit based. This is only set for
      --  those files that are part of the compilation set (for instance a
      --  file in an extended project that is overridden will not have this
      --  field set).

      Index : Int := 0;
      --  Index of the source in a multi unit source file (the same Source_Data
      --  is duplicated several times when there are several units in the same
      --  file). Index is 0 if there is either no unit or a single one, and
      --  starts at 1 when there are multiple units

      Compilable : Yes_No_Unknown := Unknown;
      --  Updated at the first call to Is_Compilable. Yes if source file is
      --  compilable.

      In_The_Queue : Boolean := False;
      --  True if the source has been put in the queue

      Locally_Removed : Boolean := False;
      --  True if the source has been "excluded"

      Suppressed : Boolean := False;
      --  True if the source is a locally removed direct source of the project.
      --  These sources should not be put in the mapping file.

      Replaced_By : Source_Id := No_Source;
      --  Source in an extending project that replaces the current source

      File : File_Name_Type := No_File;
      --  Canonical file name of the source

      Display_File : File_Name_Type := No_File;
      --  File name of the source, for display purposes

      Path : Path_Information := No_Path_Information;
      --  Path name of the source

      Source_TS : Time_Stamp_Type := Empty_Time_Stamp;
      --  Time stamp of the source file

      Checksum  : Word := 0;
      --  Checksum calculated from source file

      Checksum_Src : File_Name_Type := No_File;
      --  Source of checksum.
      --  No_File        - No checksum
      --  First_Name_Id  - Calculated from source file
      --  Other values   - From dependency file of source simple name

      Object_Project : Project_Id := No_Project;
      --  Project where the object file is. This might be different from
      --  Project when using extending project files.

      Object : File_Name_Type := No_File;
      --  File name of the object file

      Current_Object_Path : Path_Name_Type := No_Path;
      --  Object path of an existing object file

      Object_Path : Path_Name_Type := No_Path;
      --  Object path of the real object file

      Object_TS : Time_Stamp_Type := Empty_Time_Stamp;
      --  Object file time stamp

      Dep_Name : File_Name_Type := No_File;
      --  Dependency file simple name

      Dep_Path : Path_Name_Type := No_Path;
      --  Path name of the real dependency file

      Dep_TS : aliased File_Attributes := Unknown_Attributes;
      --  Dependency file time stamp

      Switches : File_Name_Type := No_File;
      --  File name of the switches file. For all languages, this is a file
      --  that ends with the .cswi extension.

      Switches_Path : Path_Name_Type := No_Path;
      --  Path name of the switches file

      Switches_TS : Time_Stamp_Type := Empty_Time_Stamp;
      --  Switches file time stamp

      Naming_Exception : Naming_Exception_Type := No;
      --  True if the source has an exceptional name

      Duplicate_Unit : Boolean := False;
      --  True when a duplicate unit has been reported for this source

      Next_In_Lang : Source_Id := No_Source;
      --  Link to another source of the same language in the same project

      Next_With_File_Name : Source_Id := No_Source;
      --  Link to another source with the same base file name

      Roots : Roots_Access := null;
      --  The roots for a main unit

   end record;

   No_Source_Data : constant Source_Data :=
                      (Initialized            => False,
                       Project                => No_Project,
                       Location               => No_Location,
                       Source_Dir_Rank        => 0,
                       Language               => No_Language_Index,
                       In_Interfaces          => True,
                       Declared_In_Interfaces => False,
                       In_Src_Subdir          => False,
                       Alternate_Languages    => null,
                       Kind                   => Spec,
                       Unit                   => No_Unit_Index,
                       Index                  => 0,
                       Locally_Removed        => False,
                       Suppressed             => False,
                       Compilable             => Unknown,
                       In_The_Queue           => False,
                       Replaced_By            => No_Source,
                       File                   => No_File,
                       Display_File           => No_File,
                       Path                   => No_Path_Information,
                       Source_TS              => Empty_Time_Stamp,
                       Checksum               => 0,
                       Checksum_Src           => No_File,
                       Object_Project         => No_Project,
                       Object                 => No_File,
                       Current_Object_Path    => No_Path,
                       Object_Path            => No_Path,
                       Object_TS              => Empty_Time_Stamp,
                       Dep_Name               => No_File,
                       Dep_Path               => No_Path,
                       Dep_TS                 => Unknown_Attributes,
                       Switches               => No_File,
                       Switches_Path          => No_Path,
                       Switches_TS            => Empty_Time_Stamp,
                       Naming_Exception       => No,
                       Duplicate_Unit         => False,
                       Next_In_Lang           => No_Source,
                       Next_With_File_Name    => No_Source,
                       Roots                  => null);

   package Source_Files_Htable is new Simple_HTable
     (Header_Num => Header_Num,
      Element    => Source_Id,
      No_Element => No_Source,
      Key        => File_Name_Type,
      Hash       => Hash,
      Equal      => "=");
   --  Mapping of source file names to source ids

   package Source_Paths_Htable is new Simple_HTable
     (Header_Num => Header_Num,
      Element    => Source_Id,
      No_Element => No_Source,
      Key        => Path_Name_Type,
      Hash       => Hash,
      Equal      => "=");
   --  Mapping of source paths to source ids

   type Lib_Kind is (Static, Static_Pic, Dynamic, Relocatable);

   function Image (Kind : Lib_Kind) return String;
   --  Return image of Lib_kind as used in project files

   type Policy is (Restricted, Unrestricted);
   --  Type to specify the symbol policy, when symbol control is supported.
   --    Restricted:    Restrict the symbols to those in the symbol file
   --    Unrestrictedt: All symbols are exported

   type Symbol_Record is record
      Symbol_File   : Path_Name_Type := No_Path;
      Symbol_Policy : Policy  := Restricted;
   end record;
   --  Type to keep the symbol data to be used when building a shared library

   No_Symbols : constant Symbol_Record :=
     (Symbol_File   => No_Path,
      Symbol_Policy => Restricted);
   --  The default value of the symbol data

   function Image (The_Casing : Casing_Type) return String;
   --  Similar to 'Image (but avoid use of this attribute in compiler)

   function Value (Image : String) return Casing_Type;
   --  Similar to 'Value (but avoid use of this attribute in compiler)
   --  Raises Constraint_Error if not a Casing_Type image.

   function Hex_Image (Item : Word; Length : Positive := 8) return String;
   --  Returns hexadecimal Item representation.
   --  Result string would be with size Length.
   --  If Length is not enough for representation, raise Constrant_Error.

   procedure Hex_Image (Item : Word; Result : out String);
   --  Write Item hexadecimal representation into Result. Raise
   --  Constraint_Error if Result length is not enough.

   --  The following record contains data for a naming scheme

   function Get_Object_Directory
     (Project             : Project_Id;
      Including_Libraries : Boolean;
      Only_If_Ada         : Boolean := False) return Path_Name_Type;
   --  Return the object directory to use for the project. This depends on
   --  whether we have a library project or a standard project. This function
   --  might return No_Name when no directory applies. If the project is a
   --  library project file and Including_Libraries is True then the library
   --  ALI dir is returned instead of the object dir, except when there is no
   --  ALI files in the Library ALI dir and the object directory exists. If
   --  Only_If_Ada is True, then No_Name is returned when the project doesn't
   --  include any Ada source.

   procedure Compute_All_Imported_Projects
     (Root_Project : Project_Id;
      Tree         : Project_Tree_Ref);
   --  For all projects in the tree, compute the list of the projects imported
   --  directly or indirectly by project Root_Project. The result is stored in
   --  Project.All_Imported_Projects for each project

   function Ultimate_Extending_Project_Of
     (Proj : Project_Id; Before : Project_Id := No_Project) return Project_Id;
   --  Returns the ultimate extending project of project Proj. If project Proj
   --  is not extended, returns Proj.
   --  If Before is defined, returns last extending project before it.

   type Project_List_Element;
   type Project_List is access all Project_List_Element;
   type Project_List_Element is record
      Project               : Project_Id   := No_Project;
      From_Encapsulated_Lib : Boolean      := False;
      Next                  : Project_List := null;
   end record;
   --  A list of projects

   procedure Free_List
     (List         : in out Project_List;
      Free_Project : Boolean);
   --  Free the list of projects, if Free_Project, each project is also freed

   type Export_File_Format is
     (None,
      Flat,
      GNU,
      Def);
   --  The format of the different exported symbol files

   type Project_Configuration is record
      Target : Name_Id := No_Name;
      --  The target of the configuration, when specified

      Run_Path_Option : Name_List_Index := No_Name_List;
      --  The option to use when linking to specify the path where to look for
      --  libraries.

      Run_Path_Origin : Name_Id := No_Name;
      --  Specify the string (such as "$ORIGIN") to indicate paths relative to
      --  the directory of the executable in the run path option.

      Library_Install_Name_Option : Name_Id := No_Name;
      --  When this is not an empty list, this option, followed by the single
      --  name of the shared library file is used when linking a shared
      --  library.

      Separate_Run_Path_Options : Boolean := False;
      --  True if each directory needs to be specified in a separate run path
      --  option.

      Executable_Suffix : Name_Id := No_Name;
      --  The suffix of executables, when specified in the configuration or in
      --  package Builder of the main project. When this is not specified, the
      --  executable suffix is the default for the platform.

      --  Linking

      Linker : Path_Name_Type := No_Path;
      --  Path name of the linker driver. Specified in the configuration or in
      --  the package Builder of the main project.

      Map_File_Option : Name_Id := No_Name;
      --  Option to use when invoking the linker to build a map file

      Trailing_Linker_Required_Switches : Name_List_Index := No_Name_List;
      --  The minimum options for the linker driver. Specified in the
      --  configuration.

      Linker_Executable_Option : Name_List_Index := No_Name_List;
      --  The option(s) to indicate the name of the executable in the linker
      --  command. Specified in the configuration. When not specified, default
      --  to -o <executable name>.

      Linker_Lib_Dir_Option : Name_Id := No_Name;
      --  The option to specify where to find a library for linking. Specified
      --  in the configuration. When not specified, defaults to "-L".

      Linker_Lib_Name_Option : Name_Id := No_Name;
      --  The option to specify the name of a library for linking. Specified in
      --  the configuration. When not specified, defaults to "-l".

      Max_Command_Line_Length : Natural := 0;
      --  When positive and when Resp_File_Format (see below) is not None,
      --  if the command line for the invocation of the linker would be greater
      --  than this value, a response file is used to invoke the linker.
      --  Also used for compiler supporting response files.

      Resp_File_Format : Response_File_Format := None;
      --  The format of a response file, when linking with a response file is
      --  supported.

      Resp_File_Options : Name_List_Index := No_Name_List;
      --  The switches, if any, that precede the path name of the response
      --  file in the invocation of the linker.

      --  Libraries

      Library_Builder : Path_Name_Type  := No_Path;
      --  The executable to build library (specified in the configuration)

      Lib_Support : Library_Support := None;
      --  The level of library support. Specified in the configuration. Support
      --  is none, static libraries only or both static and shared libraries.

      Lib_Encapsulated_Supported : Boolean := False;
      --  True when building fully standalone libraries supported on the target

      Archive_Builder : Name_List_Index := No_Name_List;
      --  The name of the executable to build archives, with the minimum
      --  switches. Specified in the configuration.

      Archive_Builder_Append_Option : Name_List_Index := No_Name_List;
      --  The options to append object files to an archive

      Archive_Indexer : Name_List_Index := No_Name_List;
      --  The name of the executable to index archives, with the minimum
      --  switches. Specified in the configuration.

      Archive_Suffix : File_Name_Type := No_File;
      --  The suffix of archives. Specified in the configuration. When not
      --  specified, defaults to ".a".

      Object_Lister : Name_List_Index := No_Name_List;
      --  The object lister if any defined

      Object_Lister_Matcher : Name_Id := No_Name;
      --  Pattern to match symbols out of the object lister output

      Export_File_Format : GPR.Export_File_Format := GPR.None;
      --  The format of the expor file

      Export_File_Switch : Name_Id := No_Name;
      --  Swicth to pass the export file to the linker

      Lib_Partial_Linker : Name_List_Index := No_Name_List;

      --  Shared libraries

      Shared_Lib_Driver : File_Name_Type := No_File;
      --  The driver to link shared libraries. Set with attribute Library_GCC.
      --  Default to gcc.

      Shared_Lib_Prefix : File_Name_Type := No_File;
      --  Part of a shared library file name that precedes the name of the
      --  library. Specified in the configuration. When not specified, defaults
      --  to "lib".

      Shared_Lib_Suffix : File_Name_Type := No_File;
      --  Suffix of shared libraries, after the library name in the shared
      --  library name. Specified in the configuration. When not specified,
      --  default to ".so".

      Shared_Lib_Min_Options : Name_List_Index := No_Name_List;
      --  The minimum options to use when building a shared library

      Lib_Version_Options : Name_List_Index := No_Name_List;
      --  The options to use to specify a library version

      Symbolic_Link_Supported : Boolean := False;
      --  True if the platform supports symbolic link files

      Lib_Maj_Min_Id_Supported : Boolean := False;
      --  True if platform supports library major and minor options, such as
      --  libname.so -> libname.so.2 -> libname.so.2.4

      Auto_Init_Supported : Boolean := False;
      --  True if automatic initialisation is supported for shared stand-alone
      --  libraries.

      --  Cleaning

      Artifacts_In_Exec_Dir : Name_List_Index := No_Name_List;
      --  List of regexp file names to be cleaned in the exec directory of the
      --  main project.

      Artifacts_In_Object_Dir : Name_List_Index := No_Name_List;
      --  List of regexp file names to be cleaned in the object directory of
      --  all projects.
   end record;

   Default_Project_Config : constant Project_Configuration :=
                              (Target                         => No_Name,
                               Run_Path_Option                => No_Name_List,
                               Run_Path_Origin                => No_Name,
                               Library_Install_Name_Option    => No_Name,
                               Separate_Run_Path_Options      => False,
                               Executable_Suffix              => No_Name,
                               Linker                         => No_Path,
                               Map_File_Option                => No_Name,
                               Trailing_Linker_Required_Switches =>
                                 No_Name_List,
                               Linker_Executable_Option       => No_Name_List,
                               Linker_Lib_Dir_Option          => No_Name,
                               Linker_Lib_Name_Option         => No_Name,
                               Library_Builder                => No_Path,
                               Max_Command_Line_Length        => 0,
                               Resp_File_Format               => None,
                               Resp_File_Options              => No_Name_List,
                               Lib_Support                    => None,
                               Lib_Encapsulated_Supported     => False,
                               Archive_Builder                => No_Name_List,
                               Archive_Builder_Append_Option  => No_Name_List,
                               Archive_Indexer                => No_Name_List,
                               Archive_Suffix                 => No_File,
                               Object_Lister                  => No_Name_List,
                               Object_Lister_Matcher          => No_Name,
                               Export_File_Format             => GPR.None,
                               Export_File_Switch             => No_Name,
                               Lib_Partial_Linker             => No_Name_List,
                               Shared_Lib_Driver              => No_File,
                               Shared_Lib_Prefix              => No_File,
                               Shared_Lib_Suffix              => No_File,
                               Shared_Lib_Min_Options         => No_Name_List,
                               Lib_Version_Options            => No_Name_List,
                               Symbolic_Link_Supported        => False,
                               Lib_Maj_Min_Id_Supported       => False,
                               Auto_Init_Supported            => False,
                               Artifacts_In_Exec_Dir          => No_Name_List,
                               Artifacts_In_Object_Dir        => No_Name_List);

   -------------------------
   -- Aggregated projects --
   -------------------------

   type Project_Node_Kind is
     (N_Project,
      N_With_Clause,
      N_Project_Declaration,
      N_Declarative_Item,
      N_Package_Declaration,
      N_String_Type_Declaration,
      N_Literal_String,
      N_Attribute_Declaration,
      N_Typed_Variable_Declaration,
      N_Variable_Declaration,
      N_Expression,
      N_Term,
      N_Literal_String_List,
      N_Variable_Reference,
      N_External_Value,
      N_Attribute_Reference,
      N_Split,
      N_Case_Construction,
      N_Case_Item,
      N_Comment_Zones,
      N_Comment);
   --  Each node in the tree is of a Project_Node_Kind. For the signification
   --  of the fields in each node of Project_Node_Kind, look at package
   --  Tree_Private_Part.

   subtype Variable_Node_Id is Project_Node_Id;
   --  Used to designate a node whose expected kind is one of
   --  N_Typed_Variable_Declaration, N_Variable_Declaration or
   --  N_Variable_Reference.

   subtype Package_Declaration_Id is Project_Node_Id;
   --  Used to designate a node whose expected kind is N_Project_Declaration

   Packages_Initial   : constant := 10;
   Packages_Increment : constant := 100;

   Package_Node_Low_Bound  : constant := 0;
   Package_Node_High_Bound : constant := 099_999_999;

   type Pkg_Node_Id is
     range Package_Node_Low_Bound .. Package_Node_High_Bound;
   --  Index type for table Package_Attributes in the body

   type Package_Node_Id is record
      Value : Pkg_Node_Id := Package_Node_Low_Bound;
   end record;
   --  Full declaration of self-initialized private type

   Empty_Pkg       : constant Pkg_Node_Id     := Package_Node_Low_Bound;
   Empty_Package   : constant Package_Node_Id := (Value => Empty_Pkg);
   Unknown_Pkg     : constant Pkg_Node_Id     := Package_Node_High_Bound;
   Unknown_Package : constant Package_Node_Id := (Value => Unknown_Pkg);

   -------------------
   -- Miscellaneous --
   -------------------

   procedure Add_To_Path
     (Directory : String;
      Append    : Boolean := False;
      Variable  : String := "PATH");
   --  Add a directory to the path environment variable (by default "PATH").
   --  If the variable is not defined or if its value is the empty string, set
   --  the value of the variable to Directory;
   --  Otherwise update the variable with Directory either in the front or in
   --  the back, depending on the value of parameter Append, using a
   --  Path_Separator after or before Directory.

   -------------------------------
   -- Restricted Access Section --
   -------------------------------

   package Tree_Private_Part is

      --  This is conceptually in the private part. However, for efficiency,
      --  some packages are accessing it directly.

      type Project_Node_Record is record

         Kind : Project_Node_Kind;

         Qualifier : Project_Qualifier := Unspecified;

         Location : Source_Ptr := No_Location;

         Directory : Path_Name_Type := No_Path;
         --  Only for N_Project

         Display_Name : Name_Id := No_Name;
         --  Only for N_Project

         Expr_Kind : Variable_Kind := Undefined;
         --  See below for what Project_Node_Kind it is used

         Variables : Variable_Node_Id := Empty_Project_Node;
         --  First variable in a project or a package

         Packages : Package_Declaration_Id := Empty_Project_Node;
         --  First package declaration in a project

         Pkg_Id : Package_Node_Id := Empty_Package;
         --  Only used for N_Package_Declaration
         --
         --  The component Pkg_Id is an entry into the table Package_Attributes
         --  (in Prj.Attr). It is used to indicate all the attributes of the
         --  package with their characteristics.
         --
         --  The tables Prj.Attr.Attributes and Prj.Attr.Package_Attributes
         --  are built once and for all through a call (from Prj.Initialize)
         --  to procedure Prj.Attr.Initialize. It is never modified after that.

         Name : Name_Id := No_Name;
         --  See below for what Project_Node_Kind it is used

         Src_Index : Int := 0;
         --  Index of a unit in a multi-unit source.
         --  Only for some N_Attribute_Declaration and N_Literal_String.

         Path_Name : Path_Name_Type := No_Path;
         --  See below for what Project_Node_Kind it is used

         Value : Name_Id := No_Name;
         --  See below for what Project_Node_Kind it is used

         Default : Attribute_Default_Value := Empty_Value;
         --  Only used in N_Attribute_Reference

         Field1 : Project_Node_Id := Empty_Project_Node;
         --  See below the meaning for each Project_Node_Kind

         Field2 : Project_Node_Id := Empty_Project_Node;
         --  See below the meaning for each Project_Node_Kind

         Field3 : Project_Node_Id := Empty_Project_Node;
         --  See below the meaning for each Project_Node_Kind

         Field4 : Project_Node_Id := Empty_Project_Node;
         --  See below the meaning for each Project_Node_Kind

         Flag1 : Boolean := False;
         --  This flag is significant only for:
         --
         --    N_Attribute_Declaration and N_Attribute_Reference
         --      Indicates for an associative array attribute, that the
         --      index is case insensitive.
         --
         --    N_Comment
         --      Indicates that the comment is preceded by an empty line.
         --
         --    N_Project
         --      Indicates that there are comments in the project source that
         --      cannot be kept in the tree.
         --
         --    N_Project_Declaration
         --      Indicates that there are unkept comments in the project.
         --
         --    N_With_Clause
         --      Indicates that this is not the last with in a with clause.
         --      Set for "A", but not for "B" in with "B"; and with "A", "B";

         Flag2 : Boolean := False;
         --  This flag is significant only for:
         --
         --    N_Attribute_Declaration and N_Attribute_Reference
         --      Indicates if attribute values are concatenated with the value
         --      in the configuration project for the same attribute.
         --
         --    N_Project
         --      Indicates that the project "extends all" another project.
         --
         --    N_Comment
         --      Indicates that the comment is followed by an empty line.
         --
         --    N_With_Clause
         --      Indicates that the originally imported project is an extending
         --      all project.

         Comments : Project_Node_Id := Empty_Project_Node;
         --  For nodes other that N_Comment_Zones or N_Comment, designates the
         --  comment zones associated with the node.
         --
         --  For N_Comment_Zones, designates the comment after the "end" of
         --  the construct.
         --
         --  For N_Comment, designates the next comment, if any.

         Checksum : Word := 0;
         --  Checksum taken from parser

      end record;

      --  type Project_Node_Kind is

      --   (N_Project,
      --    --  Name:      project name
      --    --  Path_Name: project path name
      --    --  Expr_Kind: Undefined
      --    --  Field1:    first with clause
      --    --  Field2:    project declaration
      --    --  Field3:    first string type
      --    --  Field4:    parent project, if any
      --    --  Value:     extended project path name (if any)

      --    N_With_Clause,
      --    --  Name:      imported project name
      --    --  Path_Name: imported project path name
      --    --  Expr_Kind: Undefined
      --    --  Field1:    project node
      --    --  Field2:    next with clause
      --    --  Field3:    project node or empty if "limited with"
      --    --  Field4:    not used
      --    --  Value:     literal string withed

      --    N_Project_Declaration,
      --    --  Name:      not used
      --    --  Path_Name: not used
      --    --  Expr_Kind: Undefined
      --    --  Field1:    first declarative item
      --    --  Field2:    extended project
      --    --  Field3:    extending project
      --    --  Field4:    not used
      --    --  Value:     not used

      --    N_Declarative_Item,
      --    --  Name:      not used
      --    --  Path_Name: not used
      --    --  Expr_Kind: Undefined
      --    --  Field1:    current item node
      --    --  Field2:    next declarative item
      --    --  Field3:    not used
      --    --  Field4:    not used
      --    --  Value:     not used

      --    N_Package_Declaration,
      --    --  Name:      package name
      --    --  Path_Name: not used
      --    --  Expr_Kind: Undefined
      --    --  Field1:    project of renamed package (if any)
      --    --  Field2:    first declarative item
      --    --  Field3:    next package in project
      --    --  Field4:    not used
      --    --  Value:     not used

      --    N_String_Type_Declaration,
      --    --  Name:      type name
      --    --  Path_Name: not used
      --    --  Expr_Kind: Undefined
      --    --  Field1:    first literal string
      --    --  Field2:    next string type
      --    --  Field3:    project node
      --    --  Field4:    not used
      --    --  Value:     not used

      --    N_Literal_String,
      --    --  Name:      not used
      --    --  Path_Name: not used
      --    --  Expr_Kind: Single
      --    --  Field1:    next literal string
      --    --  Field2:    not used
      --    --  Field3:    not used
      --    --  Field4:    not used
      --    --  Value:     string value

      --    N_Attribute_Declaration,
      --    --  Name:      attribute name
      --    --  Path_Name: not used
      --    --  Expr_Kind: attribute kind
      --    --  Field1:    expression
      --    --  Field2:    project of full associative array
      --    --  Field3:    package of full associative array
      --    --  Field4:    not used
      --    --  Value:     associative array index
      --    --             (if an associative array element)

      --    N_Typed_Variable_Declaration,
      --    --  Name:      variable name
      --    --  Path_Name: not used
      --    --  Expr_Kind: Single
      --    --  Field1:    expression
      --    --  Field2:    type of variable (N_String_Type_Declaration)
      --    --  Field3:    next variable
      --    --  Field4:    project node
      --    --  Value:     not used

      --    N_Variable_Declaration,
      --    --  Name:      variable name
      --    --  Path_Name: not used
      --    --  Expr_Kind: variable kind
      --    --  Field1:    expression
      --    --  Field2:    not used
      --    --             Field3 is used for next variable, instead of Field2,
      --    --             so that it is the same field for
      --    --             N_Variable_Declaration and
      --    --             N_Typed_Variable_Declaration
      --    --  Field3:    next variable
      --    --  Field4:    not used
      --    --  Value:     not used

      --    N_Expression,
      --    --  Name:      not used
      --    --  Path_Name: not used
      --    --  Expr_Kind: expression kind
      --    --  Field1:    first term
      --    --  Field2:    next expression in list
      --    --  Field3:    not used
      --    --  Value:     not used

      --    N_Term,
      --    --  Name:      not used
      --    --  Path_Name: not used
      --    --  Expr_Kind: term kind
      --    --  Field1:    current term
      --    --  Field2:    next term in the expression
      --    --  Field3:    not used
      --    --  Field4:    not used
      --    --  Value:     not used

      --    N_Literal_String_List,
      --    --  Designates a list of string expressions between brackets
      --    --  separated by commas. The string expressions are not necessarily
      --    --  literal strings.
      --    --  Name:      not used
      --    --  Path_Name: not used
      --    --  Expr_Kind: List
      --    --  Field1:    first expression
      --    --  Field2:    not used
      --    --  Field3:    not used
      --    --  Field4:    not used
      --    --  Value:     not used

      --    N_Variable_Reference,
      --    --  Name:      variable name
      --    --  Path_Name: not used
      --    --  Expr_Kind: variable kind
      --    --  Field1:    project (if specified)
      --    --  Field2:    package (if specified)
      --    --  Field3:    type of variable (N_String_Type_Declaration), if any
      --    --  Field4:    not used
      --    --  Value:     not used

      --    N_External_Value,
      --    --  Name:      not used
      --    --  Path_Name: not used
      --    --  Expr_Kind: Single
      --    --  Field1:    Name of the external reference (literal string)
      --    --  Field2:    Default (literal string)
      --    --  Field3:    not used
      --    --  Value:     not used

      --    N_Split,
      --    --  Name:      not used
      --    --  Path_Name: not used
      --    --  Expr_Kind: List
      --    --  Field1:    expression to split (single string)
      --    --  Field2:    expression of separator (single string)
      --    --  Field3:    not used
      --    --  Value:     not used

      --    N_Attribute_Reference,
      --    --  Name:      attribute name
      --    --  Path_Name: not used
      --    --  Expr_Kind: attribute kind
      --    --  Field1:    project
      --    --  Field2:    package (if attribute of a package)
      --    --  Field3:    not used
      --    --  Field4:    not used
      --    --  Value:     associative array index
      --    --             (if an associative array element)

      --    N_Case_Construction,
      --    --  Name:      not used
      --    --  Path_Name: not used
      --    --  Expr_Kind: Undefined
      --    --  Field1:    case variable reference
      --    --  Field2:    first case item
      --    --  Field3:    not used
      --    --  Field4:    not used
      --    --  Value:     not used

      --    N_Case_Item
      --    --  Name:      not used
      --    --  Path_Name: not used
      --    --  Expr_Kind: not used
      --    --  Field1:    first choice (literal string), or Empty_Node
      --    --             for when others
      --    --  Field2:    first declarative item
      --    --  Field3:    next case item
      --    --  Field4:    not used
      --    --  Value:     not used

      --    N_Comment_zones
      --    --  Name:      not used
      --    --  Path_Name: not used
      --    --  Expr_Kind: not used
      --    --  Field1:    comment before the construct
      --    --  Field2:    comment after the construct
      --    --  Field3:    comment before the "end" of the construct
      --    --  Value:     end of line comment
      --    --  Field4:    not used
      --    --  Comments:  comment after the "end" of the construct

      --    N_Comment
      --    --  Name:      not used
      --    --  Path_Name: not used
      --    --  Expr_Kind: not used
      --    --  Field1:    not used
      --    --  Field2:    not used
      --    --  Field3:    not used
      --    --  Field4:    not used
      --    --  Value:     comment
      --    --  Flag1:     comment is preceded by an empty line
      --    --  Flag2:     comment is followed by an empty line
      --    --  Comments:  next comment

      package Project_Node_Table is new
        GNAT.Dynamic_Tables
          (Table_Component_Type => Project_Node_Record,
           Table_Index_Type     => Project_Node_Id,
           Table_Low_Bound      => First_Project_Node_Id,
           Table_Initial        => Project_Nodes_Initial,
           Table_Increment      => Project_Nodes_Increment);
      --  Table contains the syntactic tree of project data from project files

      type Project_Name_And_Node is record
         Name : Name_Id;
         --  Name of the project

         Node : Project_Node_Id;
         --  Node of the project in table Project_Nodes

         Resolved_Path : Path_Name_Type;
         --  Resolved and canonical path of a real project file.
         --  No_Name in case of virtual projects.

         Extended : Boolean;
         --  True when the project is being extended by another project

         From_Extended : Boolean;
         --  True when the project is only imported by projects that are
         --  extended.

         Proj_Qualifier : Project_Qualifier;
         --  The project qualifier of the project, if any
      end record;

      No_Project_Name_And_Node : constant Project_Name_And_Node :=
        (Name           => No_Name,
         Node           => Empty_Project_Node,
         Resolved_Path  => No_Path,
         Extended       => True,
         From_Extended  => False,
         Proj_Qualifier => Unspecified);

      package Projects_Htable is new GNAT.Dynamic_HTables.Simple_HTable
        (Header_Num => Header_Num,
         Element    => Project_Name_And_Node,
         No_Element => No_Project_Name_And_Node,
         Key        => Name_Id,
         Hash       => Hash,
         Equal      => "=");
      --  This hash table contains a mapping of project names to project nodes.
      --  Note that this hash table contains only the nodes whose Kind is
      --  N_Project. It is used to find the node of a project from its name,
      --  and to verify if a project has already been parsed, knowing its name.

   end Tree_Private_Part;

   type Project_Node_Tree_Data is record
      Project_Nodes : Tree_Private_Part.Project_Node_Table.Instance;
      Projects_HT   : Tree_Private_Part.Projects_Htable.Instance;

      Incomplete_With : Boolean := False;
      --  Set to True if the projects were loaded with the flag
      --  Ignore_Missing_With set to True, and there were indeed some with
      --  statements that could not be resolved
   end record;

   type Project_Node_Tree_Ref is access all Project_Node_Tree_Data;
   --  Type to designate a project node tree, so that several project node
   --  trees can coexist in memory.

   procedure Free (Proj : in out Project_Node_Tree_Ref);
   --  Free memory used by Prj

   type Aggregated_Project;
   type Aggregated_Project_List is access all Aggregated_Project;
   type Aggregated_Project is record
      Path      : Path_Name_Type;
      Tree      : Project_Tree_Ref;
      Node_Tree : Project_Node_Tree_Ref;
      Project   : Project_Id;
      Next      : Aggregated_Project_List;
   end record;

   procedure Free (List : in out Aggregated_Project_List);
   --  Free the memory used for List

   procedure Add_Aggregated_Project
     (Project : Project_Id;
      Path    : Path_Name_Type);
   --  Add a new aggregated project in Project.
   --  The aggregated project has not been processed yet. This procedure should
   --  the called while processing the aggregate project, and as a result
   --  Prj.Proc.Process will then automatically process the aggregated projects

   ------------------
   -- Project_Data --
   ------------------

   --  The following record describes a project file representation

   type Standalone is
     (No,

      --  The following clash with Standard is OK, and justified by the context
      --  which really wants to use the same set of qualifiers.

      Standard,

      Encapsulated);

   type Project_Data (Qualifier : Project_Qualifier := Unspecified) is record

      -------------
      -- General --
      -------------

      Name : Name_Id := No_Name;
      --  The name of the project

      Display_Name : Name_Id := No_Name;
      --  The name of the project with the spelling of its declaration

      Externally_Built : Boolean := False;
      --  True if the project is externally built. In such case, the Project
      --  Manager will not modify anything in this project.

      Config : Project_Configuration;

      Path : Path_Information := No_Path_Information;
      --  The path name of the project file. This include base name of the
      --  project file.

      Virtual : Boolean := False;
      --  True for virtual extending projects

      Location : Source_Ptr := No_Location;
      --  The location in the project file source of the project name that
      --  immediately follows the reserved word "project".

      ---------------
      -- Languages --
      ---------------

      Languages : Language_Ptr := No_Language_Index;
      --  First index of the language data in the project. Traversing the list
      --  gives access to all the languages supported by the project.

      --------------
      -- Projects --
      --------------

      Mains : String_List_Id := Nil_String;
      --  List of mains specified by attribute Main

      Extends : Project_Id := No_Project;
      --  The reference of the project file, if any, that this project file
      --  extends.

      Extended_By : Project_Id := No_Project;
      --  The reference of the project file, if any, that extends this project
      --  file.

      Decl : Declarations := No_Declarations;
      --  The declarations (variables, attributes and packages) of this project
      --  file.

      Imported_Projects : Project_List := null;
      --  The list of all directly imported projects, if any

      All_Imported_Projects : Project_List := null;
      --  The list of all projects imported directly or indirectly, if any.
      --  This does not include the project itself.

      -----------------
      -- Directories --
      -----------------

      Directory : Path_Information := No_Path_Information;
      --  Path name of the directory where the project file resides

      Object_Directory : Path_Information := No_Path_Information;
      --  The path name of the object directory of this project file

      Exec_Directory : Path_Information := No_Path_Information;
      --  The path name of the exec directory of this project file. Default is
      --  equal to Object_Directory.

      Object_Path_File : Path_Name_Type := No_Path;
      --  Store the name of the temporary file that contains the list of object
      --  directories, when attribute Object_Path_Switches is declared.

      -------------
      -- Library --
      -------------

      Library : Boolean := False;
      --  True if this is a library project

      Library_Name : Name_Id := No_Name;
      --  If a library project, name of the library

      Library_Kind : Lib_Kind := Static;
      --  If a library project, kind of library

      Library_Dir : Path_Information := No_Path_Information;
      --  If a library project, path name of the directory where the library
      --  resides.

      Library_TS : Time_Stamp_Type := Empty_Time_Stamp;
      --  The timestamp of a library file in a library project

      Was_Built : Boolean := False;
      --  The library project has been built in the current gprbuild execution

      Need_Build : Boolean := False;
      --  Library project has to be built even if no need any compilation

      Library_Src_Dir : Path_Information := No_Path_Information;
      --  If a Stand-Alone Library project, path name of the directory where
      --  the sources of the interfaces of the library are copied. By default,
      --  if attribute Library_Src_Dir is not specified, sources of the
      --  interfaces are not copied anywhere.

      Library_ALI_Dir : Path_Information := No_Path_Information;
      --  In a library project, path name of the directory where the ALI files
      --  are copied. If attribute Library_ALI_Dir is not specified, ALI files
      --  are copied in the Library_Dir.

      Lib_Internal_Name : Name_Id := No_Name;
      --  If a library project, internal name store inside the library

      Standalone_Library : Standalone := No;
      --  Indicate that this is a Standalone Library Project File

      Lib_Interface_ALIs : String_List_Id := Nil_String;
      --  For Standalone Library Project Files, list of Interface ALI files

      Other_Interfaces : String_List_Id := Nil_String;
      --  List of non unit based sources in attribute Interfaces

      Lib_Auto_Init : Boolean := False;
      --  For non static Stand-Alone Library Project Files, True if the library
      --  initialisation should be automatic.

      Symbol_Data : Symbol_Record := No_Symbols;
      --  Symbol file name, reference symbol file name, symbol policy

      -------------
      -- Sources --
      -------------
      --  The sources for all languages including Ada are accessible through
      --  the Source_Iterator type

      Interfaces_Defined : Boolean := False;
      --  True if attribute Interfaces is declared for the project or any
      --  project it extends.

      Include_Path_File : Path_Name_Type := No_Path;
      --  The path name of the of the source search directory file.
      --  This is only used by gnatmake

      Source_Dirs : String_List_Id := Nil_String;
      --  The list of all the source directories

      Source_Dir_Ranks : Number_List_Index := No_Number_List;

      Ada_Include_Path : String_Access := null;
      --  The cached value of source search path for this project file. Set by
      --  the first call to Prj.Env.Ada_Include_Path for the project. Do not
      --  use this field directly outside of the project manager, use
      --  Prj.Env.Ada_Include_Path instead.

      Has_Multi_Unit_Sources : Boolean := False;
      --  Whether there is at least one source file containing multiple units

      -------------------
      -- Miscellaneous --
      -------------------

      Ada_Objects_Path : String_Access := null;
      --  The cached value of ADA_OBJECTS_PATH for this project file, with
      --  library ALI directories for library projects instead of object
      --  directories. Do not use this field directly outside of the
      --  compiler, use Prj.Env.Ada_Objects_Path instead.

      Ada_Objects_Path_No_Libs : String_Access := null;
      --  The cached value of ADA_OBJECTS_PATH for this project file with all
      --  object directories (no library ALI dir for library projects).

      Libgnarl_Needed : Yes_No_Unknown := Unknown;
      --  Set to True when libgnarl is needed to link

      Objects_Path : String_Access := null;
      --  The cached value of the object dir path, used during the binding
      --  phase of gprbuild.

      Objects_Path_File_With_Libs : Path_Name_Type := No_Path;
      --  The cached value of the object path temp file (including library
      --  dirs) for this project file.

      Objects_Path_File_Without_Libs : Path_Name_Type := No_Path;
      --  The cached value of the object path temp file (excluding library
      --  dirs) for this project file.

      Config_File_Name : Path_Name_Type := No_Path;
      --  The path name of the configuration pragmas file, if any

      Config_File_Temp : Boolean := False;
      --  True if the configuration pragmas file is a temporary file that must
      --  be deleted at the end.

      Config_Checked : Boolean := False;
      --  A flag to avoid checking repetitively the configuration pragmas file

      Depth : Natural := 0;
      --  The maximum depth of a project in the project graph. Depth of main
      --  project is 0.

      Unkept_Comments : Boolean := False;
      --  True if there are comments in the project sources that cannot be kept
      --  in the project tree.

      Checksum : Word := 0;
      --  Checksum of the project taken from parser

      -----------------------------
      -- Qualifier-Specific data --
      -----------------------------

      --  The following fields are only valid for specific types of projects

      case Qualifier is
         when Aggregate | Aggregate_Library =>
            Aggregated_Projects : Aggregated_Project_List := null;
            --  List of aggregated projects (which could themselves be
            --  aggregate projects).

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

   function Empty_Project (Qualifier : Project_Qualifier) return Project_Data;
   --  Return the representation of an empty project

   function Is_Extending
     (Extending : Project_Id;
      Extended  : Project_Id) return Boolean;
   --  Return True if Extending is extending the Extended project

   function Is_Ext
     (Extending : Project_Id;
      Extended  : Project_Id) return Boolean renames Is_Extending;

   function Has_Ada_Sources (Data : Project_Id) return Boolean;
   --  Return True if the project has Ada sources

   Project_Error : exception;
   --  Raised by some subprograms in Prj.Attr

   package Units_Htable is new Simple_HTable
     (Header_Num => Header_Num,
      Element    => Unit_Index,
      No_Element => No_Unit_Index,
      Key        => Name_Id,
      Hash       => Hash,
      Equal      => "=");
   --  Mapping of unit names to indexes in the Units table

   ---------------------
   -- Source_Iterator --
   ---------------------

   type Source_Iterator is private;

   function For_Each_Source
     (In_Tree           : Project_Tree_Ref;
      Project           : Project_Id := No_Project;
      Language          : Name_Id    := No_Name;
      Encapsulated_Libs : Boolean    := True;
      Locally_Removed   : Boolean    := True) return Source_Iterator;
   --  Returns an iterator for all the sources of a project tree, or a specific
   --  project, or a specific language. Include sources from encapsulated
   --  stand-alone libs if Encapsulated_Libs is True. If Locally_Removed is set
   --  to False the Locally_Removed files won't be reported.

   function Element (Iter : Source_Iterator) return Source_Id;
   --  Return the current source (or No_Source if there are no more sources)

   procedure Next (Iter : in out Source_Iterator);
   --  Move on to the next source

   function Find_Source
     (In_Tree          : Project_Tree_Ref;
      Project          : Project_Id;
      In_Imported_Only : Boolean := False;
      In_Extended_Only : Boolean := False;
      Base_Name        : File_Name_Type;
      Index            : Int := 0) return Source_Id;
   --  Find the first source file with the given name.
   --  If In_Extended_Only is True, it will search in project and the project
   --     it extends, but not in the imported projects.
   --  Elsif In_Imported_Only is True, it will search in project and the
   --     projects it imports, but not in the others or in aggregated projects.
   --  Else it searches in the whole tree.
   --  If Index is specified, this only search for a source with that index.

   type Source_Ids is array (Positive range <>) of Source_Id;
   No_Sources : constant Source_Ids := (1 .. 0 => No_Source);

   function Find_All_Sources
     (In_Tree          : Project_Tree_Ref;
      Project          : Project_Id;
      In_Imported_Only : Boolean := False;
      In_Extended_Only : Boolean := False;
      Base_Name        : File_Name_Type;
      Index            : Int     := 0) return Source_Ids;
   --  Find all source files with the given name:
   --
   --    If In_Extended_Only is True, it will search in project and the project
   --    it extends, but not in the imported projects.
   --
   --    If Extended_Only is False, and In_Imported_Only is True, it will
   --    search in project and the projects it imports, but not in the others
   --    or in aggregated projects.
   --
   --    If both Extended_Only and In_Imported_Only are False (the default)
   --    then it searches the whole tree.
   --
   --  If Index is specified, this only search for sources with that index.

   -----------------------
   -- Project_Tree_Data --
   -----------------------

   package Replaced_Source_HTable is new Simple_HTable
     (Header_Num => Header_Num,
      Element    => File_Name_Type,
      No_Element => No_File,
      Key        => File_Name_Type,
      Hash       => Hash,
      Equal      => "=");

   type Private_Project_Tree_Data is private;
   --  Data for a project tree that is used only by the Project Manager

   type Shared_Project_Tree_Data is record
      Name_Lists        : Name_List_Table.Instance;
      Number_Lists      : Number_List_Table.Instance;
      String_Elements   : String_Element_Table.Instance;
      Variable_Elements : Variable_Element_Table.Instance;
      Array_Elements    : Array_Element_Table.Instance;
      Arrays            : Array_Table.Instance;
      Packages          : Package_Table.Instance;
      Private_Part      : Private_Project_Tree_Data;
      Dot_String_List   : String_List_Id := Nil_String;

      Ada_Runtime_Dir             : Name_Id := No_Name;
      Ada_Runtime_Source_Dirs     : Name_List_Index := No_Name_List;
      Ada_Runtime_Library_Dirs    : Name_List_Index := No_Name_List;
      Ada_Runtime_Library_Version : Name_Id := No_Name;
   end record;
   type Shared_Project_Tree_Data_Access is access all Shared_Project_Tree_Data;
   --  The data that is shared among multiple trees, when these trees are
   --  loaded through the same aggregate project.
   --  To avoid ambiguities, limit the number of parameters to the
   --  subprograms (we would have to parse the "root project tree" since this
   --  is where the configuration file was loaded, in addition to the project's
   --  own tree) and make the comparison of projects easier, all trees store
   --  the lists in the same tables.

   type Project_Tree_Appdata is tagged null record;
   type Project_Tree_Appdata_Access is access all Project_Tree_Appdata'Class;
   --  Application-specific data that can be associated with a project tree.
   --  We do not make the Project_Tree_Data itself tagged for several reasons:
   --    - it couldn't have a default value for its discriminant
   --    - it would require a "factory" to allocate such data, because trees
   --      are created automatically when parsing aggregate projects.

   procedure Free (Tree : in out Project_Tree_Appdata);
   --  Should be overridden if your derive your own data

   type Project_Tree_Data (Is_Root_Tree : Boolean := True) is record
      --  The root tree is the one loaded by the user from the command line.
      --  Is_Root_Tree is only false for projects aggregated within a root
      --  aggregate project.

      Projects : Project_List;
      --  List of projects in this tree

      Replaced_Sources : Replaced_Source_HTable.Instance;
      --  The list of sources that have been replaced by sources with
      --  different file names.

      Replaced_Source_Number : Natural := 0;
      --  The number of entries in Replaced_Sources

      Units_HT : Units_Htable.Instance;
      --  Unit name to Unit_Index (and from there to Source_Id)

      Source_Files_HT : Source_Files_Htable.Instance;
      --  Base source file names to Source_Id list

      Source_Paths_HT : Source_Paths_Htable.Instance;
      --  Full path to Source_Id
      --  ??? What is behavior for multi-unit source files, where there are
      --  several source_id per file ?

      Source_Info_File_Name : String_Access := null;
      --  The name of the source info file, if specified by the builder

      Source_Info_File_Exists : Boolean := False;
      --  True when a source info file has been successfully read

      Shared : Shared_Project_Tree_Data_Access;
      --  The shared data for this tree and all aggregated trees

      Appdata : Project_Tree_Appdata_Access;
      --  Application-specific data for this tree

      case Is_Root_Tree is
         when True =>
            Shared_Data : aliased Shared_Project_Tree_Data;
            --  Do not access directly, only through Shared

         when False =>
            null;
      end case;
   end record;
   --  Data for a project tree

   function Debug_Name (Tree : Project_Tree_Ref) return Name_Id;
   --  If debug traces are activated, return an identitier for the project
   --  tree. This modifies Name_Buffer.

   procedure Initialize (Tree : Project_Tree_Ref);
   --  This procedure must be called before using any services from the Prj
   --  hierarchy. Namet.Initialize must be called before Prj.Initialize.

   procedure Reset (Tree : Project_Tree_Ref);
   --  This procedure resets all the tables that are used when processing a
   --  project file tree. Initialize must be called before the call to Reset.

   package Project_Boolean_Htable is new Simple_HTable
     (Header_Num => Header_Num,
      Element    => Boolean,
      No_Element => False,
      Key        => Project_Id,
      Hash       => Hash,
      Equal      => "=");
   --  A table that associates a project to a boolean. This is used to detect
   --  whether a project was already processed for instance.

   generic
      with procedure Action (Project : Project_Id; Tree : Project_Tree_Ref);
   procedure For_Project_And_Aggregated
     (Root_Project : Project_Id;
      Root_Tree    : Project_Tree_Ref);
   --  Execute Action for Root_Project and all its aggregated projects
   --  recursively.

   generic
      type State is limited private;
      with procedure Action
        (Project    : Project_Id;
         Tree       : Project_Tree_Ref;
         With_State : in out State);
   procedure For_Every_Project_Imported
     (By                 : Project_Id;
      Tree               : Project_Tree_Ref;
      With_State         : in out State;
      Include_Aggregated : Boolean := True;
      Imported_First     : Boolean := False);
   --  Call Action for each project imported directly or indirectly by project
   --  By, as well as extended projects.
   --
   --  The order of processing depends on Imported_First:
   --
   --    If False, Action is called according to the order of importation: if A
   --    imports B, directly or indirectly, Action will be called for A before
   --    it is called for B. If two projects import each other directly or
   --    indirectly (using at least one "limited with"), it is not specified
   --    for which of these two projects Action will be called first.
   --
   --    The order is reversed if Imported_First is True
   --
   --  With_State may be used by Action to choose a behavior or to report some
   --  global result.
   --
   --  If Include_Aggregated is True, then an aggregate project will recurse
   --  into the projects it aggregates. Otherwise, the latter are never
   --  returned.
   --
   --  In_Aggregate_Lib is True if the project is in an aggregate library
   --
   --  The Tree argument passed to the callback is required in the case of
   --  aggregated projects, since they might not be using the same tree as 'By'

   type Project_Context is record
      In_Aggregate_Lib : Boolean;
      --  True if the project is part of an aggregate library

      From_Encapsulated_Lib : Boolean;
      --  True if the project is imported from an encapsulated library
   end record;

   generic
      type State is limited private;
      with procedure Action
        (Project    : Project_Id;
         Tree       : Project_Tree_Ref;
         Context    : Project_Context;
         With_State : in out State);
   procedure For_Every_Project_Imported_Context
     (By                 : Project_Id;
      Tree               : Project_Tree_Ref;
      With_State         : in out State;
      Include_Aggregated : Boolean := True;
      Imported_First     : Boolean := False);
   --  As for For_Every_Project_Imported but with an associated context

   generic
      with procedure Action
        (Project : Project_Id;
         Tree    : Project_Tree_Ref;
         Context : Project_Context);
   procedure For_Project_And_Aggregated_Context
     (Root_Project : Project_Id;
      Root_Tree    : Project_Tree_Ref);
   --  As for For_Project_And_Aggregated but with an associated context

   function Extend_Name
     (File        : File_Name_Type;
      With_Suffix : String) return File_Name_Type;
   --  Replace the extension of File with With_Suffix

   function Object_Name
     (Source_File_Name   : File_Name_Type;
      Object_File_Suffix : Name_Id := No_Name) return File_Name_Type;
   --  Returns the object file name corresponding to a source file name

   function Object_Name
     (Source_File_Name   : File_Name_Type;
      Source_Index       : Int;
      Index_Separator    : Character;
      Object_File_Suffix : Name_Id := No_Name) return File_Name_Type;
   --  Returns the object file name corresponding to a unit in a multi-source
   --  file.

   function Dependency_Name
     (Source_File_Name : File_Name_Type;
      Dependency       : Dependency_File_Kind) return File_Name_Type;
   --  Returns the dependency file name corresponding to a source file name

   function Switches_Name
     (Source_File_Name : File_Name_Type) return File_Name_Type;
   --  Returns the switches file name corresponding to a source file name

   procedure Set_Path_File_Var (Name : String; Value : String);
   --  Call Setenv, after calling To_Host_File_Spec

   function Current_Source_Path_File_Of
     (Shared : Shared_Project_Tree_Data_Access) return Path_Name_Type;
   --  Get the current include path file name

   procedure Set_Current_Source_Path_File_Of
     (Shared : Shared_Project_Tree_Data_Access;
      To     : Path_Name_Type);
   --  Record the current include path file name

   function Current_Object_Path_File_Of
     (Shared : Shared_Project_Tree_Data_Access) return Path_Name_Type;
   --  Get the current object path file name

   procedure Set_Current_Object_Path_File_Of
     (Shared : Shared_Project_Tree_Data_Access;
      To     : Path_Name_Type);
   --  Record the current object path file name

   -----------
   -- Flags --
   -----------

   type Processing_Flags is private;
   --  Flags used while parsing and processing a project tree to configure the
   --  behavior of the parser, and indicate how to report error messages. This
   --  structure does not allocate memory and never needs to be freed

   type Error_Warning is (Silent, Warning, Error, Decide_Later);
   --  Severity of some situations, such as: no Ada sources in a project where
   --  Ada is one of the language.
   --
   --  When the situation occurs, the behaviour depends on the setting:
   --
   --    - Silent:       no action
   --    - Warning:      issue a warning, does not cause the tool to fail
   --    - Error:        issue an error, causes the tool to fail
   --    - Decide_Later: keep the message until call to Messages_Decision

   subtype Decided_Message is Error_Warning range Error_Warning'First .. Error;

   type Error_Handler is access procedure
     (Project    : Project_Id;
      Is_Warning : Boolean);
   --  This warns when an error was found when parsing a project. The error
   --  itself is handled through Prj.Err (and Prj.Err.Finalize should be called
   --  to actually print the error). This ensures that duplicate error messages
   --  are always correctly removed, that errors msgs are sorted, and that all
   --  tools will report the same error to the user.

   function Create_Flags
     (Report_Error               : Error_Handler;
      When_No_Sources            : Error_Warning;
      Require_Sources_Other_Lang : Boolean       := True;
      Allow_Duplicate_Basenames  : Boolean       := True;
      Compiler_Driver_Mandatory  : Boolean       := False;
      Error_On_Unknown_Language  : Boolean       := True;
      Require_Obj_Dirs           : Error_Warning := Error;
      Allow_Invalid_External     : Error_Warning := Error;
      Missing_Project_Files      : Error_Warning := Error;
      Missing_Source_Files       : Error_Warning := Error;
      Ignore_Missing_With        : Boolean       := False;
      Check_Configuration_Only   : Boolean       := False)
      return Processing_Flags;
   --  Function used to create Processing_Flags structure
   --
   --  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).
   --
   --  If Compiler_Driver_Mandatory is true, then a Compiler.Driver attribute
   --  for each language must be defined, or we will not look for its source
   --  files.
   --
   --  When_No_Sources indicates what should be done when no sources of a
   --  language are found in a project where this language is declared.
   --  If Require_Sources_Other_Lang is true, then all languages must have at
   --  least one source file, or an error is reported via When_No_Sources. If
   --  it is false, this is only required for Ada (and only if it is a language
   --  of the project). When this parameter is set to False, we do not check
   --  that a proper naming scheme is defined for languages other than Ada.
   --
   --  If Report_Error is null, use the standard error reporting mechanism
   --  (Errout). Otherwise, report errors using Report_Error.
   --
   --  If Error_On_Unknown_Language is true, an error is displayed if some of
   --  the source files listed in the project do not match any naming scheme
   --
   --  If Require_Obj_Dirs is true, then all object directories must exist
   --  (possibly after they have been created automatically if the appropriate
   --  switches were specified), or an error is raised.
   --
   --  If Allow_Invalid_External is Silent, then no error is reported when an
   --  invalid value is used for an external variable (and it doesn't match its
   --  type). Instead, the first possible value is used.
   --
   --  Missing_Source_Files indicates whether it is an error or a warning that
   --  a source file mentioned in the Source_Files attributes is not actually
   --  found in the source directories. This also impacts errors for missing
   --  source directories.
   --
   --  If Ignore_Missing_With is True, then a "with" statement that cannot be
   --  resolved will simply be ignored. However, in such a case, the flag
   --  Incomplete_With in the project tree will be set to True.
   --  This is meant for use by tools so that they can properly set the
   --  project path in such a case:
   --       * no "gnatls" found (so no default project path)
   --       * user project sets Project.IDE'gnatls attribute to a cross gnatls
   --       * user project also includes a "with" that can only be resolved
   --         once we have found the gnatls

   procedure Set_Ignore_Missing_With
     (Flags : in out Processing_Flags;
      Value : Boolean);
   --  Set the value of component Ignore_Missing_With in Flags to Value

   procedure Set_Require_Obj_Dirs
     (Flags : in out Processing_Flags;
      Value : Error_Warning);
   --  Set the value of component Require_Object_Dirs in Flags to Value

   procedure Set_Check_Configuration_Only
     (Flags : in out Processing_Flags;
      Value : Boolean);
   --  Set the value of component Check_Configuration_Only in Flags to Value

   procedure Set_Missing_Source_Files
     (Flags : in out Processing_Flags;
      Value : Error_Warning);
   --  Set the value of component Missing_Source_Files in Flags to Value

   Gprbuild_Flags   : constant Processing_Flags;
   Gprinstall_Flags : constant Processing_Flags;
   Gprclean_Flags   : constant Processing_Flags;
   Gprname_Flags    : constant Processing_Flags;
   Gprls_Flags      : constant Processing_Flags;
   --  Flags used by the various tools. They all display the error messages
   --  through Prj.Err.

   ----------------
   -- Temp Files --
   ----------------

   procedure Record_Temp_File
     (Shared : Shared_Project_Tree_Data_Access;
      Path   : Path_Name_Type);
   --  Record the path of a newly created temporary file, so that it can be
   --  deleted later.

   procedure Delete_All_Temp_Files
     (Shared : Shared_Project_Tree_Data_Access);
   --  Delete all recorded temporary files.
   --  Does nothing if Debug.Debug_Flag_N is set

   procedure Delete_Temporary_File
     (Shared : Shared_Project_Tree_Data_Access := null;
      Path   : Path_Name_Type);
   procedure Delete_Temporary_File
     (Shared : Shared_Project_Tree_Data_Access := null;
      Path   : String);
   --  Delete a temporary file from the disk. The file is also removed from the
   --  list of temporary files to delete at the end of the program, in case
   --  another program running on the same machine has recreated it. Does
   --  nothing if Debug.Debug_Flag_N is set

   Virtual_Prefix : constant String := "v$";
   --  The prefix for virtual extending projects. Because of the '$', which is
   --  normally forbidden for project names, there cannot be any name clash.

   -----------
   -- Debug --
   -----------

   type Verbosity is (Default, Medium, High);
   pragma Ordered (Verbosity);
   --  Verbosity when parsing GNAT Project Files
   --    Default is default (very quiet, if no errors).
   --    Medium is more verbose.
   --    High is extremely verbose.

   Current_Verbosity : Verbosity := Default;
   --  The current value of the verbosity the project files are parsed with

   procedure Debug_Indent;
   --  Inserts a series of blanks depending on the current indentation level

   procedure Debug_Output (Str : String);
   procedure Debug_Output (Str : String; Str2 : Name_Id);
   --  If Current_Verbosity is not Default, outputs Str.
   --  This indents Str based on the current indentation level for traces
   --  Debug_Error is intended to be used to report an error in the traces.

   procedure Debug_Increase_Indent
     (Str : String := ""; Str2 : Name_Id := No_Name);
   procedure Debug_Decrease_Indent (Str : String := "");
   --  Increase or decrease the indentation level for debug traces. This
   --  indentation level only affects output done through Debug_Output.

   Total_Errors_Detected : Nat := 0;

   Warnings_Detected : Nat := 0;

   Native_Target : Boolean := False;
   --  True when no target is specified on the command line or in the main
   --  project.

   function To_Hash (Item : Name_Id) return Ada.Containers.Hash_Type;

   package Name_Id_Maps is new Ada.Containers.Hashed_Maps
     (Key_Type        => Name_Id,
      Element_Type    => Name_Id,
      Hash            => To_Hash,
      Equivalent_Keys => "=");

   package Language_Maps renames Name_Id_Maps;
   --  Hash table to keep the languages and its required versions used in
   --  the project tree.

   package Path_Name_HTable is new GNAT.Dynamic_HTables.Simple_HTable
     (Header_Num => Header_Num,
      Element    => Boolean,
      No_Element => False,
      Key        => Path_Name_Type,
      Hash       => Hash,
      Equal      => "=");

   Shared_Libgcc_Default : Character
     with Import, Convention => C, Size => Character'Size,
          External_Name => "__gnat_shared_libgcc_default";

private

   function To_Hash (Item : Name_Id) return Ada.Containers.Hash_Type
   is (Ada.Containers.Hash_Type (Item));

   Tool_Name : String_Access := null;

   Serious_Errors_Detected : Nat := 0;

   Warnings_Treated_As_Errors : Nat := 0;

   Info_Messages : Nat := 0;

   Gprls_Mode : Boolean := False;
   --  When True, an ALI file may be found in an extending project, even if
   --  the corresponding object file is not found in the same project.
   --  This is only for gprls.

   All_Packages : constant String_List_Access := null;

   No_Project_Tree : constant Project_Tree_Ref := null;

   Ignored : constant Variable_Kind := Single;

   Nil_Variable_Value : constant Variable_Value :=
                          (Project              => No_Project,
                           Kind                 => Undefined,
                           Location             => No_Location,
                           Default              => False,
                           String_Type          => Empty_Project_Node,
                           From_Implicit_Target => False);

   type Source_Iterator is record
      In_Tree : Project_Tree_Ref;

      Project      : Project_List;
      All_Projects : Boolean;
      --  Current project and whether we should move on to the next

      Language : Language_Ptr;
      --  Current language processed

      Language_Name : Name_Id;
      --  Only sources of this language will be returned (or all if No_Name)

      Current : Source_Id;

      Encapsulated_Libs : Boolean;
      --  True if we want to include the sources from encapsulated libs

      Locally_Removed : Boolean;
   end record;

   procedure Add_To_Buffer
     (S    : String;
      To   : in out String_Access;
      Last : in out Natural);
   --  Append a String to the Buffer

   --  Table used to store the path name of all the created temporary files, so
   --  that they can be deleted at the end, or when the program is interrupted.

   function Distance (L, R : String) return Natural;
   --  Damerau Levenshtein distance between L and R strings.
   --  Calculated in minimum number of elementary operations to convert one
   --  string to another. The operations are deletion, insertion, substitution,
   --  and transposition (swap 2 adjacent characters).

   package Temp_Files_Table is new GNAT.Dynamic_Tables
     (Table_Component_Type => Path_Name_Type,
      Table_Index_Type     => Integer,
      Table_Low_Bound      => 1,
      Table_Initial        => 10,
      Table_Increment      => 10);

   --  The following type is used to represent the part of a project tree which
   --  is private to the Project Manager.

   type Private_Project_Tree_Data is record
      Temp_Files   : Temp_Files_Table.Instance;
      --  Temporary files created as part of running tools (pragma files,
      --  mapping files,...)

      Current_Source_Path_File : Path_Name_Type := No_Path;
      --  Current value of project source path file env var. Used to avoid
      --  setting the env var to the same value. When different from No_Path,
      --  this indicates that environment variables were created and should be
      --  deassigned to avoid polluting the environment. For gnatmake only.

      Current_Object_Path_File : Path_Name_Type := No_Path;
      --  Current value of project object path file env var. Used to avoid
      --  setting the env var to the same value.
      --  gnatmake only
   end record;

   Executable_Extension_On_Target : Name_Id := No_Name;

   --  The following type is used to hold processing flags which show what
   --  functions are required for the various tools that are handled.

   type Processing_Flags is record
      Require_Sources_Other_Lang : Boolean;
      Report_Error               : Error_Handler;
      When_No_Sources            : Error_Warning;
      Allow_Duplicate_Basenames  : Boolean;
      Compiler_Driver_Mandatory  : Boolean;
      Error_On_Unknown_Language  : Boolean;
      Require_Obj_Dirs           : Error_Warning;
      Allow_Invalid_External     : Error_Warning;
      Missing_Project_Files      : Error_Warning;
      Missing_Source_Files       : Error_Warning;
      Ignore_Missing_With        : Boolean;
      Check_Configuration_Only   : Boolean;

      Incomplete_Withs : Boolean := False;
      --  This flag is set to True when the projects are parsed while ignoring
      --  missing withed project and some withed projects are not found.

   end record;

   Gprbuild_Flags   : constant Processing_Flags :=
                        (Report_Error               => null,
                         When_No_Sources            => Warning,
                         Require_Sources_Other_Lang => True,
                         Allow_Duplicate_Basenames  => False,
                         Compiler_Driver_Mandatory  => True,
                         Error_On_Unknown_Language  => True,
                         Require_Obj_Dirs           => Error,
                         Allow_Invalid_External     => Error,
                         Missing_Project_Files      => Error,
                         Missing_Source_Files       => Error,
                         Ignore_Missing_With        => False,
                         Incomplete_Withs           => False,
                         Check_Configuration_Only   => False);

   Gprinstall_Flags : constant Processing_Flags :=
                        (Report_Error               => null,
                         When_No_Sources            => Warning,
                         Require_Sources_Other_Lang => True,
                         Allow_Duplicate_Basenames  => False,
                         Compiler_Driver_Mandatory  => True,
                         Error_On_Unknown_Language  => True,
                         Require_Obj_Dirs           => Silent,
                         Allow_Invalid_External     => Error,
                         Missing_Project_Files      => Error,
                         Missing_Source_Files       => Error,
                         Ignore_Missing_With        => False,
                         Incomplete_Withs           => False,
                         Check_Configuration_Only   => False);

   Gprclean_Flags   : constant Processing_Flags :=
                        (Report_Error               => null,
                         When_No_Sources            => Warning,
                         Require_Sources_Other_Lang => True,
                         Allow_Duplicate_Basenames  => False,
                         Compiler_Driver_Mandatory  => True,
                         Error_On_Unknown_Language  => True,
                         Require_Obj_Dirs           => Warning,
                         Allow_Invalid_External     => Error,
                         Missing_Project_Files      => Error,
                         Missing_Source_Files       => Error,
                         Ignore_Missing_With        => False,
                         Incomplete_Withs           => False,
                         Check_Configuration_Only   => False);

   Gprname_Flags    : constant Processing_Flags :=
                        (Report_Error               => null,
                         When_No_Sources            => Warning,
                         Require_Sources_Other_Lang => True,
                         Allow_Duplicate_Basenames  => False,
                         Compiler_Driver_Mandatory  => True,
                         Error_On_Unknown_Language  => True,
                         Require_Obj_Dirs           => Error,
                         Allow_Invalid_External     => Error,
                         Missing_Project_Files      => Error,
                         Missing_Source_Files       => Error,
                         Ignore_Missing_With        => False,
                         Incomplete_Withs           => False,
                         Check_Configuration_Only   => True);

   Gprls_Flags      : constant Processing_Flags :=
                        (Report_Error               => null,
                         When_No_Sources            => Warning,
                         Require_Sources_Other_Lang => True,
                         Allow_Duplicate_Basenames  => False,
                         Compiler_Driver_Mandatory  => True,
                         Error_On_Unknown_Language  => True,
                         Require_Obj_Dirs           => Error,
                         Allow_Invalid_External     => Error,
                         Missing_Project_Files      => Error,
                         Missing_Source_Files       => Error,
                         Ignore_Missing_With        => False,
                         Incomplete_Withs           => False,
                         Check_Configuration_Only   => False);
end GPR;
