[multiple changes]

2009-09-17  Bob Duff  <duff@adacore.com>

	* gnat_rm.texi, s-oscons-tmplt.c: Minor typo

2009-09-17  Emmanuel Briot  <briot@adacore.com>

	* gnatcmd.adb, prj-proc.adb, make.adb, prj-ext.adb, prj-ext.ads,
	makeutl.adb, makeutl.ads, clean.adb, prj-pars.adb, prj-pars.ads,
	prj-conf.adb, prj-conf.ads, prj-tree.adb, prj-tree.ads, prj-proc.ads,
	prj-nmsc.ads (Add, Value_Of, Reset): new parameter Tree.
	Scenario variables are now specific to each project tree loaded in
	memory.
	Code clean ups.

2009-09-17  Javier Miranda  <miranda@adacore.com>

	* exp_disp.adb (Make_DT): Remove wrong line of code that was
	undocumented and probably added by mistake.

From-SVN: r151792

20 files changed, 220 insertions, 102 deletions

diff --git a/gcc/ada/ChangeLog b/gcc/ada/ChangeLog
index dae5c00..f908caf 100644
--- a/gcc/ada/ChangeLog
+++ b/gcc/ada/ChangeLog
@@ -1,3 +1,22 @@
+2009-09-17  Bob Duff  <duff@adacore.com>
+
+	* gnat_rm.texi, s-oscons-tmplt.c: Minor typo
+
+2009-09-17  Emmanuel Briot  <briot@adacore.com>
+
+	* gnatcmd.adb, prj-proc.adb, make.adb, prj-ext.adb, prj-ext.ads,
+	makeutl.adb, makeutl.ads, clean.adb, prj-pars.adb, prj-pars.ads,
+	prj-conf.adb, prj-conf.ads, prj-tree.adb, prj-tree.ads, prj-proc.ads,
+	prj-nmsc.ads (Add, Value_Of, Reset): new parameter Tree.
+	Scenario variables are now specific to each project tree loaded in
+	memory.
+	Code clean ups.
+
+2009-09-17  Javier Miranda  <miranda@adacore.com>
+
+	* exp_disp.adb (Make_DT): Remove wrong line of code that was
+	undocumented and probably added by mistake.
+
 2009-09-16  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* gcc-interface/trans.c (Attribute_to_gnu) <Attr_Size>: Strip
diff --git a/gcc/ada/clean.adb b/gcc/ada/clean.adb
index 790b842..a113e6b 100644
--- a/gcc/ada/clean.adb
+++ b/gcc/ada/clean.adb
@@ -35,6 +35,7 @@ with Prj;      use Prj;
 with Prj.Env;
 with Prj.Ext;
 with Prj.Pars;
+with Prj.Tree; use Prj.Tree;
 with Prj.Util; use Prj.Util;
 with Snames;
 with Switch;   use Switch;
@@ -90,7 +91,7 @@ package body Clean is
 
    Project_File_Name : String_Access := null;
 
-   Project_Tree : constant Prj.Project_Tree_Ref := new Prj.Project_Tree_Data;
+   Project_Node_Tree : Project_Node_Tree_Ref;
 
    Main_Project : Prj.Project_Id := Prj.No_Project;
 
@@ -1402,6 +1403,7 @@ package body Clean is
          Prj.Pars.Parse
            (Project           => Main_Project,
             In_Tree           => Project_Tree,
+            In_Node_Tree      => Project_Node_Tree,
             Project_File_Name => Project_File_Name.all,
             Flags             => Gnatmake_Flags,
             Packages_To_Check => Packages_To_Check_By_Gnatmake);
@@ -1556,6 +1558,10 @@ package body Clean is
          Csets.Initialize;
          Namet.Initialize;
          Snames.Initialize;
+
+         Project_Node_Tree := new Project_Node_Tree_Data;
+         Prj.Tree.Initialize (Project_Node_Tree);
+
          Prj.Initialize (Project_Tree);
 
          --  Check if the platform is VMS and, if it is, change some variables
@@ -1873,7 +1879,8 @@ package body Clean is
 
                            if OK then
                               Prj.Ext.Add
-                                (External_Name =>
+                                (Project_Node_Tree,
+                                 External_Name =>
                                    Ext_Asgn (Start .. Equal_Pos - 1),
                                  Value         =>
                                    Ext_Asgn (Equal_Pos + 1 .. Stop));
diff --git a/gcc/ada/exp_disp.adb b/gcc/ada/exp_disp.adb
index 34aacef..00fd9f2 100644
--- a/gcc/ada/exp_disp.adb
+++ b/gcc/ada/exp_disp.adb
@@ -5140,9 +5140,8 @@ package body Exp_Disp is
 
             exit when Parent_Typ = Current_Typ;
 
-            if Is_CPP_Class (Parent_Typ)
-              or else Is_Interface (Typ)
-            then
+            if Is_CPP_Class (Parent_Typ) then
+
                --  The tags defined in the C++ side will be inherited when
                --  the object is constructed (Exp_Ch3.Build_Init_Procedure)
 
diff --git a/gcc/ada/gnat_rm.texi b/gcc/ada/gnat_rm.texi
index 1f26563..e25400d 100644
--- a/gcc/ada/gnat_rm.texi
+++ b/gcc/ada/gnat_rm.texi
@@ -7733,11 +7733,11 @@ Followed.
 In addition to the implementation dependent pragmas and attributes, and
 the implementation advice, there are a number of other Ada features
 that are potentially implementation dependent.  These are mentioned
-throughout the Ada Reference Manual, and are summarized in annex M@.
+throughout the Ada Reference Manual, and are summarized in Annex M@.
 
 A requirement for conforming Ada compilers is that they provide
 documentation describing how the implementation deals with each of these
-issues.  In this chapter, you will find each point in annex M listed
+issues.  In this chapter, you will find each point in Annex M listed
 followed by a description in italic font of how GNAT
 @c SGI info:
 @ignore
diff --git a/gcc/ada/gnatcmd.adb b/gcc/ada/gnatcmd.adb
index 42d08dc..d3f74c0 100644
--- a/gcc/ada/gnatcmd.adb
+++ b/gcc/ada/gnatcmd.adb
@@ -26,7 +26,7 @@
 with GNAT.Directory_Operations; use GNAT.Directory_Operations;
 
 with Csets;
-with Makeutl;
+with Makeutl;  use Makeutl;
 with MLib.Tgt; use MLib.Tgt;
 with MLib.Utl;
 with MLib.Fil;
@@ -38,6 +38,7 @@ with Prj;      use Prj;
 with Prj.Env;
 with Prj.Ext;  use Prj.Ext;
 with Prj.Pars;
+with Prj.Tree; use Prj.Tree;
 with Prj.Util; use Prj.Util;
 with Sinput.P;
 with Snames;   use Snames;
@@ -57,7 +58,7 @@ with GNAT.OS_Lib;             use GNAT.OS_Lib;
 with VMS_Conv;                use VMS_Conv;
 
 procedure GNATCmd is
-   Project_Tree      : constant Project_Tree_Ref := new Project_Tree_Data;
+   Project_Node_Tree : Project_Node_Tree_Ref;
    Project_File      : String_Access;
    Project           : Prj.Project_Id;
    Current_Verbosity : Prj.Verbosity := Prj.Default;
@@ -1268,6 +1269,9 @@ begin
 
    Snames.Initialize;
 
+   Project_Node_Tree := new Project_Node_Tree_Data;
+   Prj.Tree.Initialize (Project_Node_Tree);
+
    Prj.Initialize (Project_Tree);
 
    Last_Switches.Init;
@@ -1694,7 +1698,8 @@ begin
                      begin
                         if Equal_Pos >= Argv'First + 3 and then
                           Equal_Pos /= Argv'Last then
-                           Add (External_Name =>
+                           Add (Project_Node_Tree,
+                                External_Name =>
                                   Argv (Argv'First + 2 .. Equal_Pos - 1),
                                 Value => Argv (Equal_Pos + 1 .. Argv'Last));
                         else
@@ -1753,6 +1758,7 @@ begin
          Prj.Pars.Parse
            (Project           => Project,
             In_Tree           => Project_Tree,
+            In_Node_Tree      => Project_Node_Tree,
             Project_File_Name => Project_File.all,
             Flags             => Gnatmake_Flags,
             Packages_To_Check => Packages_To_Check);
@@ -2114,7 +2120,7 @@ begin
             --  arguments.
 
             for J in 1 .. Last_Switches.Last loop
-               Test_If_Relative_Path
+               GNATCmd.Test_If_Relative_Path
                  (Last_Switches.Table (J), Current_Work_Dir);
             end loop;
 
@@ -2124,7 +2130,7 @@ begin
                Project_Dir : constant String := Name_Buffer (1 .. Name_Len);
             begin
                for J in 1 .. First_Switches.Last loop
-                  Test_If_Relative_Path
+                  GNATCmd.Test_If_Relative_Path
                     (First_Switches.Table (J), Project_Dir);
                end loop;
             end;
diff --git a/gcc/ada/make.adb b/gcc/ada/make.adb
index b19aa22..5471c971 100644
--- a/gcc/ada/make.adb
+++ b/gcc/ada/make.adb
@@ -49,10 +49,16 @@ with Prj;      use Prj;
 with Prj.Com;
 with Prj.Env;
 with Prj.Pars;
+with Prj.Tree; use Prj.Tree;
 with Prj.Util;
 with SFN_Scan;
 with Sinput.P;
 with Snames;   use Snames;
+
+pragma Warnings (Off);
+with System.HTable;
+pragma Warnings (On);
+
 with Switch;   use Switch;
 with Switch.M; use Switch.M;
 with Targparm; use Targparm;
@@ -68,8 +74,6 @@ with GNAT.Dynamic_HTables;      use GNAT.Dynamic_HTables;
 with GNAT.Case_Util;            use GNAT.Case_Util;
 with GNAT.OS_Lib;               use GNAT.OS_Lib;
 
-with System.HTable;
-
 package body Make is
 
    use ASCII;
@@ -640,7 +644,7 @@ package body Make is
    --  directory of the ultimate extending project. If it is not, we ignore
    --  the fact that this ALI file is read-only.
 
-   procedure Process_Multilib;
+   procedure Process_Multilib (Project_Node_Tree : Project_Node_Tree_Ref);
    --  Add appropriate --RTS argument to handle multilib
 
    ----------------------------------------------------
@@ -710,7 +714,8 @@ package body Make is
       File_Name                        : String;
       Index                            : Int;
       Program                          : Make_Program_Type;
-      Unknown_Switches_To_The_Compiler : Boolean := True);
+      Unknown_Switches_To_The_Compiler : Boolean := True;
+      Project_Node_Tree                : Project_Node_Tree_Ref);
    procedure Add_Switch
      (S             : String_Access;
       Program       : Make_Program_Type;
@@ -998,7 +1003,7 @@ package body Make is
    --  during a compilation are also transitively included in the W section
    --  of the originally compiled file.
 
-   procedure Initialize;
+   procedure Initialize (Project_Node_Tree : out Project_Node_Tree_Ref);
    --  Performs default and package initialization. Therefore,
    --  Compile_Sources can be called by an external unit.
 
@@ -1010,8 +1015,13 @@ package body Make is
    --  Args must have a lower bound of 1. Success indicates if the link
    --  succeeded or not.
 
-   procedure Scan_Make_Arg (Argv : String; And_Save : Boolean);
-   --  Scan make arguments. Argv is a single argument to be processed
+   procedure Scan_Make_Arg
+     (Project_Node_Tree : Project_Node_Tree_Ref;
+      Argv              : String;
+      And_Save          : Boolean);
+   --  Scan make arguments. Argv is a single argument to be processed.
+   --  Project_Node_Tree will be used to initialize external references. It
+   --  must have been initialized.
 
    -------------------
    -- Add_Arguments --
@@ -1233,7 +1243,8 @@ package body Make is
       File_Name                        : String;
       Index                            : Int;
       Program                          : Make_Program_Type;
-      Unknown_Switches_To_The_Compiler : Boolean := True)
+      Unknown_Switches_To_The_Compiler : Boolean := True;
+      Project_Node_Tree                : Project_Node_Tree_Ref)
    is
       Switches    : Variable_Value;
       Switch_List : String_List_Id;
@@ -1274,7 +1285,8 @@ package body Make is
                         Write_Line (Argv);
                      end if;
 
-                     Scan_Make_Arg (Argv, And_Save => False);
+                     Scan_Make_Arg
+                       (Project_Node_Tree, Argv, And_Save => False);
 
                      if not Gnatmake_Switch_Found
                        and then not Switch_May_Be_Passed_To_The_Compiler
@@ -4019,6 +4031,8 @@ package body Make is
       Mapping_Path : Path_Name_Type := No_Path;
       --  The path name of the mapping file
 
+      Project_Node_Tree : Project_Node_Tree_Ref;
+
       Discard : Boolean;
       pragma Warnings (Off, Discard);
 
@@ -4366,7 +4380,7 @@ package body Make is
 
       Obsoleted.Reset;
 
-      Make.Initialize;
+      Make.Initialize (Project_Node_Tree);
 
       Bind_Shared := No_Shared_Switch'Access;
       Link_With_Shared_Libgcc := No_Shared_Libgcc_Switch'Access;
@@ -4845,7 +4859,8 @@ package body Make is
                   end if;
 
                   Add_Switches
-                    (File_Name                        => Main_Unit_File_Name,
+                    (Project_Node_Tree                => Project_Node_Tree,
+                     File_Name                        => Main_Unit_File_Name,
                      Index                            => Main_Index,
                      The_Package                      => Builder_Package,
                      Program                          => None,
@@ -4900,7 +4915,8 @@ package body Make is
                         end if;
 
                         Add_Switches
-                          (File_Name                        => " ",
+                          (Project_Node_Tree              => Project_Node_Tree,
+                           File_Name                        => " ",
                            Index                            => 0,
                            The_Package                      => Builder_Package,
                            Program                          => None,
@@ -4916,7 +4932,8 @@ package body Make is
                         end if;
 
                         Add_Switches
-                          (File_Name   => " ",
+                          (Project_Node_Tree => Project_Node_Tree,
+                           File_Name   => " ",
                            Index       => 0,
                            The_Package => Builder_Package,
                            Program     => None);
@@ -5007,10 +5024,11 @@ package body Make is
                end if;
 
                Add_Switches
-                 (File_Name   => Main_Unit_File_Name,
-                  Index       => Main_Index,
-                  The_Package => Binder_Package,
-                  Program     => Binder);
+                 (Project_Node_Tree => Project_Node_Tree,
+                  File_Name         => Main_Unit_File_Name,
+                  Index             => Main_Index,
+                  The_Package       => Binder_Package,
+                  Program           => Binder);
             end if;
 
             --  Add linker switches from the project file for the first main
@@ -5023,10 +5041,11 @@ package body Make is
                end if;
 
                Add_Switches
-                 (File_Name   => Main_Unit_File_Name,
-                  Index       => Main_Index,
-                  The_Package => Linker_Package,
-                  Program     => Linker);
+                 (Project_Node_Tree => Project_Node_Tree,
+                  File_Name         => Main_Unit_File_Name,
+                  Index             => Main_Index,
+                  The_Package       => Linker_Package,
+                  Program           => Linker);
             end if;
          end;
       end if;
@@ -6310,10 +6329,11 @@ package body Make is
                      end if;
 
                      Add_Switches
-                       (File_Name   => Main_Unit_File_Name,
-                        Index       => Main_Index,
-                        The_Package => Binder_Package,
-                        Program     => Binder);
+                       (Project_Node_Tree => Project_Node_Tree,
+                        File_Name         => Main_Unit_File_Name,
+                        Index             => Main_Index,
+                        The_Package       => Binder_Package,
+                        Program           => Binder);
                   end if;
 
                   --  Add linker switches from the project file for this main,
@@ -6327,10 +6347,11 @@ package body Make is
                      end if;
 
                      Add_Switches
-                       (File_Name   => Main_Unit_File_Name,
-                        Index       => Main_Index,
-                        The_Package => Linker_Package,
-                        Program     => Linker);
+                       (Project_Node_Tree => Project_Node_Tree,
+                        File_Name         => Main_Unit_File_Name,
+                        Index             => Main_Index,
+                        The_Package       => Linker_Package,
+                        Program           => Linker);
                   end if;
 
                   --  As we are using a project file, for relative paths we add
@@ -6521,7 +6542,7 @@ package body Make is
    -- Initialize --
    ----------------
 
-   procedure Initialize is
+   procedure Initialize (Project_Node_Tree : out Project_Node_Tree_Ref) is
 
       procedure Check_Version_And_Help is
          new Check_Version_And_Help_G (Makeusg);
@@ -6529,6 +6550,13 @@ package body Make is
       --  Start of processing for Initialize
 
    begin
+      --  Prepare the project's tree, since this is used to hold external
+      --  references, project path and other attributes that can be impacted by
+      --  the command line switches
+
+      Project_Node_Tree := new Project_Node_Tree_Data;
+      Prj.Tree.Initialize (Project_Node_Tree);
+
       --  Override default initialization of Check_Object_Consistency since
       --  this is normally False for GNATBIND, but is True for GNATMAKE since
       --  we do not need to check source consistency again once GNATMAKE has
@@ -6611,11 +6639,12 @@ package body Make is
       --  do not include --version or --help.
 
       Scan_Args : for Next_Arg in 1 .. Argument_Count loop
-         Scan_Make_Arg (Argument (Next_Arg), And_Save => True);
+         Scan_Make_Arg
+           (Project_Node_Tree, Argument (Next_Arg), And_Save => True);
       end loop Scan_Args;
 
       if N_M_Switch > 0 and RTS_Specified = null then
-         Process_Multilib;
+         Process_Multilib (Project_Node_Tree);
       end if;
 
       if Commands_To_Stdout then
@@ -6700,7 +6729,8 @@ package body Make is
             In_Tree           => Project_Tree,
             Project_File_Name => Project_File_Name.all,
             Packages_To_Check => Packages_To_Check_By_Gnatmake,
-            Flags             => Gnatmake_Flags);
+            Flags             => Gnatmake_Flags,
+            In_Node_Tree      => Project_Node_Tree);
 
          --  The parsing of project files may have changed the current output
 
@@ -7281,7 +7311,9 @@ package body Make is
    -- Process_Multilib --
    ----------------------
 
-   procedure Process_Multilib is
+   procedure Process_Multilib
+     (Project_Node_Tree : Project_Node_Tree_Ref)
+   is
       Output_FD         : File_Descriptor;
       Output_Name       : String_Access;
       Arg_Index         : Natural := 0;
@@ -7382,8 +7414,9 @@ package body Make is
 
       --  Otherwise add -margs --RTS=output
 
-      Scan_Make_Arg ("-margs", And_Save => True);
-      Scan_Make_Arg ("--RTS=" & Line (1 .. N_Read), And_Save => True);
+      Scan_Make_Arg (Project_Node_Tree, "-margs", And_Save => True);
+      Scan_Make_Arg
+        (Project_Node_Tree, "--RTS=" & Line (1 .. N_Read), And_Save => True);
    end Process_Multilib;
 
    -----------------------------
@@ -7485,7 +7518,11 @@ package body Make is
    -- Scan_Make_Arg --
    -------------------
 
-   procedure Scan_Make_Arg (Argv : String; And_Save : Boolean) is
+   procedure Scan_Make_Arg
+     (Project_Node_Tree : Project_Node_Tree_Ref;
+      Argv              : String;
+      And_Save          : Boolean)
+   is
       Success : Boolean;
 
    begin
@@ -8001,7 +8038,7 @@ package body Make is
          --  -Xext=val  (External assignment)
 
          elsif Argv (2) = 'X'
-           and then Is_External_Assignment (Argv)
+           and then Is_External_Assignment (Project_Node_Tree, Argv)
          then
             --  Is_External_Assignment has side effects
             --  when it returns True;
diff --git a/gcc/ada/makeutl.adb b/gcc/ada/makeutl.adb
index c0d9de4..9caf9c4 100644
--- a/gcc/ada/makeutl.adb
+++ b/gcc/ada/makeutl.adb
@@ -447,7 +447,10 @@ package body Makeutl is
    -- Is_External_Assignment --
    ----------------------------
 
-   function Is_External_Assignment (Argv : String) return Boolean is
+   function Is_External_Assignment
+     (Tree : Prj.Tree.Project_Node_Tree_Ref;
+      Argv : String) return Boolean
+   is
       Start     : Positive := 3;
       Finish    : Natural := Argv'Last;
       Equal_Pos : Natural;
@@ -478,7 +481,8 @@ package body Makeutl is
          return False;
       else
          Prj.Ext.Add
-           (External_Name => Argv (Start .. Equal_Pos - 1),
+           (Tree          => Tree,
+            External_Name => Argv (Start .. Equal_Pos - 1),
             Value         => Argv (Equal_Pos + 1 .. Finish));
          return True;
       end if;
diff --git a/gcc/ada/makeutl.ads b/gcc/ada/makeutl.ads
index 1dff5a1..95114f0 100644
--- a/gcc/ada/makeutl.ads
+++ b/gcc/ada/makeutl.ads
@@ -28,6 +28,7 @@ with Namet; use Namet;
 with Opt;
 with Osint;
 with Prj;   use Prj;
+with Prj.Tree;
 with Types; use Types;
 
 with GNAT.OS_Lib; use GNAT.OS_Lib;
@@ -83,7 +84,9 @@ package Makeutl is
    --  source files are still associated with the same units). Return True
    --  if everything is still valid
 
-   function Is_External_Assignment (Argv : String) return Boolean;
+   function Is_External_Assignment
+     (Tree : Prj.Tree.Project_Node_Tree_Ref;
+      Argv : String) return Boolean;
    --  Verify that an external assignment switch is syntactically correct
    --
    --  Correct forms are:
diff --git a/gcc/ada/prj-conf.adb b/gcc/ada/prj-conf.adb
index 879178d..5783a53 100644
--- a/gcc/ada/prj-conf.adb
+++ b/gcc/ada/prj-conf.adb
@@ -1000,7 +1000,6 @@ package body Prj.Conf is
    begin
       --  Parse the user project tree
 
-      Prj.Tree.Initialize (Project_Node_Tree);
       Prj.Initialize (Project_Tree);
 
       Main_Project      := No_Project;
diff --git a/gcc/ada/prj-conf.ads b/gcc/ada/prj-conf.ads
index f228ae3..82b8dc3 100644
--- a/gcc/ada/prj-conf.ads
+++ b/gcc/ada/prj-conf.ads
@@ -59,6 +59,10 @@ package Prj.Conf is
    --  Find the main configuration project and parse the project tree rooted at
    --  this configuration project.
    --
+   --  Project_Node_Tree must have been initialized first (and possibly the
+   --  value for external references and project path should also have been
+   --  set).
+   --
    --  If the processing fails, Main_Project is set to No_Project. If the error
    --  happend while parsing the project itself (ie creating the tree),
    --  User_Project_Node is also set to Empty_Node.
diff --git a/gcc/ada/prj-ext.adb b/gcc/ada/prj-ext.adb
index 8098a3a..8bdc110 100644
--- a/gcc/ada/prj-ext.adb
+++ b/gcc/ada/prj-ext.adb
@@ -26,11 +26,10 @@
 with Hostparm;
 with Makeutl;  use Makeutl;
 with Osint;    use Osint;
+with Prj.Tree; use Prj.Tree;
 with Sdefault;
 with Table;
 
-with GNAT.HTable;
-
 package body Prj.Ext is
 
    Ada_Project_Path : constant String := "ADA_PROJECT_PATH";
@@ -52,19 +51,6 @@ package body Prj.Ext is
    procedure Initialize_Project_Path;
    --  Initialize Current_Project_Path
 
-   package Htable is new GNAT.HTable.Simple_HTable
-     (Header_Num => Header_Num,
-      Element    => Name_Id,
-      No_Element => No_Name,
-      Key        => Name_Id,
-      Hash       => Hash,
-      Equal      => "=");
-   --  External references are stored in this hash table, either by procedure
-   --  Add (directly or through a call to function Check) or by function
-   --  Value_Of when an environment variable is found non empty. Value_Of
-   --  first for external reference in this table, before checking the
-   --  environment. Htable is emptied (reset) by procedure Reset.
-
    package Search_Directories is new Table.Table
      (Table_Component_Type => Name_Id,
       Table_Index_Type     => Natural,
@@ -79,7 +65,8 @@ package body Prj.Ext is
    ---------
 
    procedure Add
-     (External_Name : String;
+     (Tree          : Prj.Tree.Project_Node_Tree_Ref;
+      External_Name : String;
       Value         : String)
    is
       The_Key   : Name_Id;
@@ -92,7 +79,7 @@ package body Prj.Ext is
       Name_Buffer (1 .. Name_Len) := External_Name;
       Canonical_Case_File_Name (Name_Buffer (1 .. Name_Len));
       The_Key := Name_Find;
-      Htable.Set (The_Key, The_Value);
+      Name_To_Name_HTable.Set (Tree.External_References, The_Key, The_Value);
    end Add;
 
    -----------
@@ -110,16 +97,19 @@ package body Prj.Ext is
    -- Check --
    -----------
 
-   function Check (Declaration : String) return Boolean is
+   function Check
+     (Tree        : Prj.Tree.Project_Node_Tree_Ref;
+      Declaration : String) return Boolean is
    begin
       for Equal_Pos in Declaration'Range loop
          if Declaration (Equal_Pos) = '=' then
             exit when Equal_Pos = Declaration'First;
             exit when Equal_Pos = Declaration'Last;
             Add
-              (External_Name =>
+              (Tree          => Tree,
+               External_Name =>
                  Declaration (Declaration'First .. Equal_Pos - 1),
-               Value =>
+               Value         =>
                  Declaration (Equal_Pos + 1 .. Declaration'Last));
             return True;
          end if;
@@ -294,9 +284,9 @@ package body Prj.Ext is
    -- Reset --
    -----------
 
-   procedure Reset is
+   procedure Reset (Tree : Prj.Tree.Project_Node_Tree_Ref) is
    begin
-      Htable.Reset;
+      Name_To_Name_HTable.Reset (Tree.External_References);
    end Reset;
 
    ----------------------
@@ -314,7 +304,8 @@ package body Prj.Ext is
    --------------
 
    function Value_Of
-     (External_Name : Name_Id;
+     (Tree          : Prj.Tree.Project_Node_Tree_Ref;
+      External_Name : Name_Id;
       With_Default  : Name_Id := No_Name)
       return          Name_Id
    is
@@ -325,7 +316,8 @@ package body Prj.Ext is
       Canonical_Case_File_Name (Name);
       Name_Len := Name'Length;
       Name_Buffer (1 .. Name_Len) := Name;
-      The_Value := Htable.Get (Name_Find);
+      The_Value :=
+        Name_To_Name_HTable.Get (Tree.External_References, Name_Find);
 
       if The_Value /= No_Name then
          return The_Value;
@@ -341,7 +333,8 @@ package body Prj.Ext is
             Name_Len := Env_Value'Length;
             Name_Buffer (1 .. Name_Len) := Env_Value.all;
             The_Value := Name_Find;
-            Htable.Set (External_Name, The_Value);
+            Name_To_Name_HTable.Set
+              (Tree.External_References, External_Name, The_Value);
             Free (Env_Value);
             return The_Value;
 
diff --git a/gcc/ada/prj-ext.ads b/gcc/ada/prj-ext.ads
index 931c3c5..cb9ecb7 100644
--- a/gcc/ada/prj-ext.ads
+++ b/gcc/ada/prj-ext.ads
@@ -6,7 +6,7 @@
 --                                                                          --
 --                                 S p e c                                  --
 --                                                                          --
---          Copyright (C) 2000-2007, Free Software Foundation, Inc.         --
+--          Copyright (C) 2000-2009, Free Software Foundation, Inc.         --
 --                                                                          --
 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
 -- terms of the  GNU General Public License as published  by the Free Soft- --
@@ -26,8 +26,14 @@
 --  Subprograms to set, get and cache external references, to be used as
 --  External functions in project files.
 
+with Prj.Tree;
+
 package Prj.Ext is
 
+   ------------------
+   -- Project Path --
+   ------------------
+
    Gpr_Project_Path : constant String := "GPR_PROJECT_PATH";
    --  Name of primary env. variable that contain path name(s) of directories
    --  where project files may reside.
@@ -48,22 +54,36 @@ package Prj.Ext is
    --  always start with the current directory (".") and the path separators
    --  should be the correct ones for the platform.
 
+   -------------------------
+   -- External References --
+   -------------------------
+   --  External references influence the way a project tree is processed (in
+   --  particular they provide the values for the typed string variables that
+   --  are then used in case constructions).
+   --  External references are project-tree specific, so that when multiple
+   --  trees are loaded in parallel we can have different scenarios (or even
+   --  load the same tree twice and see different views of it).
+
    procedure Add
-     (External_Name : String;
+     (Tree          : Prj.Tree.Project_Node_Tree_Ref;
+      External_Name : String;
       Value         : String);
    --  Add an external reference (or modify an existing one)
 
    function Value_Of
-     (External_Name : Name_Id;
+     (Tree          : Prj.Tree.Project_Node_Tree_Ref;
+      External_Name : Name_Id;
       With_Default  : Name_Id := No_Name)
       return          Name_Id;
    --  Get the value of an external reference, and cache it for future uses
 
-   function Check (Declaration : String) return Boolean;
+   function Check
+     (Tree        : Prj.Tree.Project_Node_Tree_Ref;
+      Declaration : String) return Boolean;
    --  Check that an external declaration <external>=<value> is correct.
    --  If it is correct, the external reference is Added.
 
-   procedure Reset;
+   procedure Reset (Tree : Prj.Tree.Project_Node_Tree_Ref);
    --  Clear the internal data structure that stores the external references
    --  and free any allocated memory.
 
diff --git a/gcc/ada/prj-nmsc.ads b/gcc/ada/prj-nmsc.ads
index eec6289..c69084f9 100644
--- a/gcc/ada/prj-nmsc.ads
+++ b/gcc/ada/prj-nmsc.ads
@@ -33,11 +33,10 @@ private package Prj.Nmsc is
       Flags        : Processing_Flags);
    --  Perform consistency and semantic checks on all the projects in the tree.
    --  This procedure interprets the various case statements in the project
-   --  based on the current environment variables (the "scenario"). After
-   --  checking the validity of the naming scheme, it searches for all the
-   --  source files of the project. The result of this procedure is a filled-in
-   --  data structure for Project_Id which contains all the information about
-   --  the project. This information is only valid while the scenario variables
-   --  are preserved.
+   --  based on the current external references. After checking the validity of
+   --  the naming scheme, it searches for all the source files of the project.
+   --  The result of this procedure is a filled-in data structure for
+   --  Project_Id which contains all the information about the project. This
+   --  information is only valid while the external references are preserved.
 
 end Prj.Nmsc;
diff --git a/gcc/ada/prj-pars.adb b/gcc/ada/prj-pars.adb
index bacbf8d..a2b1c42 100644
--- a/gcc/ada/prj-pars.adb
+++ b/gcc/ada/prj-pars.adb
@@ -45,18 +45,21 @@ package body Prj.Pars is
       Project_File_Name : String;
       Packages_To_Check : String_List_Access := All_Packages;
       Flags             : Processing_Flags;
-      Reset_Tree        : Boolean := True)
+      Reset_Tree        : Boolean := True;
+      In_Node_Tree      : Prj.Tree.Project_Node_Tree_Ref := null)
    is
       Project_Node      : Project_Node_Id := Empty_Node;
       The_Project       : Project_Id      := No_Project;
       Success           : Boolean         := True;
       Current_Dir       : constant String := Get_Current_Dir;
-      Project_Node_Tree : Prj.Tree.Project_Node_Tree_Ref;
+      Project_Node_Tree : Prj.Tree.Project_Node_Tree_Ref := In_Node_Tree;
       Automatically_Generated : Boolean;
       Config_File_Path        : String_Access;
    begin
-      Project_Node_Tree := new Project_Node_Tree_Data;
-      Prj.Tree.Initialize (Project_Node_Tree);
+      if Project_Node_Tree = null then
+         Project_Node_Tree := new Project_Node_Tree_Data;
+         Prj.Tree.Initialize (Project_Node_Tree);
+      end if;
 
       --  Parse the main project file into a tree
 
diff --git a/gcc/ada/prj-pars.ads b/gcc/ada/prj-pars.ads
index 01caff9..4e7d480 100644
--- a/gcc/ada/prj-pars.ads
+++ b/gcc/ada/prj-pars.ads
@@ -25,6 +25,8 @@
 
 --  General wrapper for the parsing of project files
 
+with Prj.Tree;
+
 package Prj.Pars is
 
    procedure Set_Verbosity (To : Verbosity);
@@ -36,20 +38,21 @@ package Prj.Pars is
       Project_File_Name : String;
       Packages_To_Check : String_List_Access := All_Packages;
       Flags             : Processing_Flags;
-      Reset_Tree        : Boolean := True);
+      Reset_Tree        : Boolean := True;
+      In_Node_Tree      : Prj.Tree.Project_Node_Tree_Ref := null);
    --  Parse and process a project files and all its imported project files, in
    --  the project tree In_Tree.
    --  All the project files are parsed (through Prj.Tree) to create a tree in
    --  memory. That tree is then processed (through Prj.Proc) to create a
-   --  expanded representation of the tree based on the current scenario
-   --  variables. This function is only a convenient wrapper over other
+   --  expanded representation of the tree based on the current external
+   --  references. This function is only a convenient wrapper over other
    --  services provided in the Prj.* package hierarchy.
    --
    --  If parsing is successful, Project is the project ID of the root project
    --  file; otherwise, Project_Id is set to No_Project. Project_Node_Tree is
    --  set to the tree (unprocessed) representation of the project file. This
    --  tree is permanently correct, whereas Project will need to be recomputed
-   --  if the scenario variables change.
+   --  if the external references change.
    --
    --  Packages_To_Check indicates the packages where any unknown attribute
    --  produces an error. For other packages, an unknown attribute produces a
@@ -57,5 +60,9 @@ package Prj.Pars is
    --
    --  When Reset_Tree is True, all the project data are removed from the
    --  project table before processing.
+   --
+   --  In_Node_Tree (if given) must have been Initialized. The main reason to
+   --  pass an existing tree, is to pass the external references that will then
+   --  be used to process the tree.
 
 end Prj.Pars;
diff --git a/gcc/ada/prj-proc.adb b/gcc/ada/prj-proc.adb
index 9893cf6..8390348 100644
--- a/gcc/ada/prj-proc.adb
+++ b/gcc/ada/prj-proc.adb
@@ -1041,7 +1041,8 @@ package body Prj.Proc is
                      end if;
                   end if;
 
-                  Value := Prj.Ext.Value_Of (Name, Default);
+                  Value := Prj.Ext.Value_Of
+                    (From_Project_Node_Tree, Name, Default);
 
                   if Value = No_Name then
                      if not Quiet_Output then
diff --git a/gcc/ada/prj-proc.ads b/gcc/ada/prj-proc.ads
index 40b5bf3..4257c900 100644
--- a/gcc/ada/prj-proc.ads
+++ b/gcc/ada/prj-proc.ads
@@ -40,7 +40,7 @@ package Prj.Proc is
       Flags                  : Prj.Processing_Flags;
       Reset_Tree             : Boolean := True);
    --  Process a project tree (ie the direct resulting of parsing a .gpr file)
-   --  based on the current scenario variables.
+   --  based on the current external references.
    --
    --  The result of this phase_1 is a partial project tree (Project) where
    --  only a few fields have been initialized (in particular the list of
diff --git a/gcc/ada/prj-tree.adb b/gcc/ada/prj-tree.adb
index 08e4977..4823a98 100644
--- a/gcc/ada/prj-tree.adb
+++ b/gcc/ada/prj-tree.adb
@@ -983,6 +983,10 @@ package body Prj.Tree is
    begin
       Project_Node_Table.Init (Tree.Project_Nodes);
       Projects_Htable.Reset (Tree.Projects_HT);
+
+      --  Do not reset the external references, in case we are reloading a
+      --  project, since we want to preserve the current environment
+      --  Name_To_Name_HTable.Reset (Tree.External_References);
    end Initialize;
 
    ----------
diff --git a/gcc/ada/prj-tree.ads b/gcc/ada/prj-tree.ads
index e587d37..991dbff 100644
--- a/gcc/ada/prj-tree.ads
+++ b/gcc/ada/prj-tree.ads
@@ -1001,7 +1001,6 @@ package Prj.Tree is
    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
@@ -1371,9 +1370,23 @@ package Prj.Tree is
 
    end Tree_Private_Part;
 
+   package Name_To_Name_HTable is new GNAT.Dynamic_HTables.Simple_HTable
+     (Header_Num => Header_Num,
+      Element    => Name_Id,
+      No_Element => No_Name,
+      Key        => Name_Id,
+      Hash       => Hash,
+      Equal      => "=");
+
    type Project_Node_Tree_Data is record
       Project_Nodes : Tree_Private_Part.Project_Node_Table.Instance;
       Projects_HT   : Tree_Private_Part.Projects_Htable.Instance;
+
+      External_References : Name_To_Name_HTable.Instance;
+      --  External references are stored in this hash table (and manipulated
+      --  through subprogrames in prj-ext.ads). External references are
+      --  project-tree specific so that one can load the same tree twice but
+      --  have two views of it, for instance.
    end record;
    --  The data for a project node tree
 
diff --git a/gcc/ada/s-oscons-tmplt.c b/gcc/ada/s-oscons-tmplt.c
index bce8648..c1075d6 100644
--- a/gcc/ada/s-oscons-tmplt.c
+++ b/gcc/ada/s-oscons-tmplt.c
@@ -58,7 +58,7 @@ pragma Style_Checks ("M32766");
  **  s-oscons-tmpl.s.
  **
  **  The default one assumes that the template can be compiled by the newly-
- **  build cross compiler. It uses markup produced in the (pseudo-)assembly
+ **  built cross compiler. It uses markup produced in the (pseudo-)assembly
  **  listing:
  **
  **     xgcc -DTARGET=\"$target\" -C -E s-oscons-tmplt.c > s-oscons-tmplt.i