2011-08-03 Emmanuel Briot <briot@adacore.com>

	* gnatcmd.adb, prj-proc.adb, prj-proc.ads, make.adb, mlib-prj.adb,
	prj.adb, prj.ads, makeutl.adb, makeutl.ads, clean.adb, prj-nmsc.adb,
	prj-util.adb, prj-util.ads, prj-conf.adb, prj-conf.ads, prj-env.adb,
	prj-env.ads (Shared_Project_Tree_Data): new type
	An aggregate project and its aggregated trees need to share the common
	data structures used for lists of strings, packages,... This makes the
	code simpler since otherwise we have to pass the root tree (also used
	for the configuration file data) in addition to the current project
	tree. This also avoids ambiguities as to which tree should be used.
	And finally this saves a bit of memory.
	(For_Every_Project_Imported): new parameter Tree.
	Since aggregated projects are using a different tree, we need to let
	the caller know which tree to use to manipulate the returned project.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@177261 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 294 insertions, 290 deletions

diff --git a/gcc/ada/prj-proc.adb b/gcc/ada/prj-proc.adb
index ac07421eb90..15491996cad 100644
--- a/gcc/ada/prj-proc.adb
+++ b/gcc/ada/prj-proc.adb
@@ -71,7 +71,7 @@ package body Prj.Proc is
      (Project       : Project_Id;
       Project_Name  : Name_Id;
       Project_Dir   : Name_Id;
-      In_Tree       : Project_Tree_Ref;
+      Shared        : Shared_Project_Tree_Data_Access;
       Decl          : in out Declarations;
       First         : Attribute_Node_Id;
       Project_Level : Boolean);
@@ -95,7 +95,7 @@ package body Prj.Proc is
       To         : in out Declarations;
       New_Loc    : Source_Ptr;
       Restricted : Boolean;
-      In_Tree    : Project_Tree_Ref);
+      Shared     : Shared_Project_Tree_Data_Access);
    --  Copy a package declaration From to To for a renamed package. Change the
    --  locations of all the attributes to New_Loc. When Restricted is
    --  True, do not copy attributes Body, Spec, Implementation, Specification
@@ -103,7 +103,7 @@ package body Prj.Proc is
 
    function Expression
      (Project                : Project_Id;
-      In_Tree                : Project_Tree_Ref;
+      Shared                 : Shared_Project_Tree_Data_Access;
       From_Project_Node      : Project_Node_Id;
       From_Project_Node_Tree : Project_Node_Tree_Ref;
       Env                    : Prj.Tree.Environment;
@@ -120,29 +120,26 @@ package body Prj.Proc is
 
    function Package_From
      (Project   : Project_Id;
-      In_Tree   : Project_Tree_Ref;
+      Shared    : Shared_Project_Tree_Data_Access;
       With_Name : Name_Id) return Package_Id;
    --  Find the package of Project whose name is With_Name
 
    procedure Process_Declarative_Items
-     (Project              : Project_Id;
-      In_Tree              : Project_Tree_Ref;
-      From_Project_Node    : Project_Node_Id;
-      Node_Tree            : Project_Node_Tree_Ref;
-      Env                  : Prj.Tree.Environment;
-      Pkg                  : Package_Id;
-      Item                 : Project_Node_Id;
-      Child_Env            : in out Prj.Tree.Environment;
-      Can_Modify_Child_Env : Boolean);
+     (Project           : Project_Id;
+      In_Tree           : Project_Tree_Ref;
+      From_Project_Node : Project_Node_Id;
+      Node_Tree         : Project_Node_Tree_Ref;
+      Env               : Prj.Tree.Environment;
+      Pkg               : Package_Id;
+      Item              : Project_Node_Id;
+      Child_Env         : in out Prj.Tree.Environment);
    --  Process declarative items starting with From_Project_Node, and put them
    --  in declarations Decl. This is a recursive procedure; it calls itself for
    --  a package declaration or a case construction.
    --
    --  Child_Env is the modified environment after seeing declarations like
    --  "for External(...) use" or "for Project_Path use" in aggregate projects.
-   --  It should have been initialized first. This environment can only be
-   --  modified if Can_Modify_Child_Env is True, otherwise all the above
-   --  attributes simply have no effect.
+   --  It should have been initialized first.
 
    procedure Recursive_Process
      (In_Tree                : Project_Tree_Ref;
@@ -150,20 +147,13 @@ package body Prj.Proc is
       From_Project_Node      : Project_Node_Id;
       From_Project_Node_Tree : Project_Node_Tree_Ref;
       Env                    : in out Prj.Tree.Environment;
-      Extended_By            : Project_Id;
-      Child_Env              : in out Prj.Tree.Environment;
-      Is_Root_Project        : Boolean);
+      Extended_By            : Project_Id);
    --  Process project with node From_Project_Node in the tree. Do nothing if
    --  From_Project_Node is Empty_Node. If project has already been processed,
    --  simply return its project id. Otherwise create a new project id, mark it
    --  as processed, call itself recursively for all imported projects and a
    --  extended project, if any. Then process the declarative items of the
    --  project.
-   --
-   --  Child_Env is the environment created from an aggregate project (new
-   --  external values or project path), and should be initialized before the
-   --  call.
-   --
    --  Is_Root_Project should be true only for the project that the user
    --  explicitly loaded. In the context of aggregate projects, only that
    --  project is allowed to modify the environment that will be used to load
@@ -209,7 +199,7 @@ package body Prj.Proc is
      (Project       : Project_Id;
       Project_Name  : Name_Id;
       Project_Dir   : Name_Id;
-      In_Tree       : Project_Tree_Ref;
+      Shared        : Shared_Project_Tree_Data_Access;
       Decl          : in out Declarations;
       First         : Attribute_Node_Id;
       Project_Level : Boolean)
@@ -272,15 +262,14 @@ package body Prj.Proc is
                end case;
 
                Variable_Element_Table.Increment_Last
-                 (In_Tree.Variable_Elements);
-               In_Tree.Variable_Elements.Table
-                 (Variable_Element_Table.Last
-                   (In_Tree.Variable_Elements)) :=
+                 (Shared.Variable_Elements);
+               Shared.Variable_Elements.Table
+                 (Variable_Element_Table.Last (Shared.Variable_Elements)) :=
                  (Next  => Decl.Attributes,
                   Name  => Attribute_Name_Of (The_Attribute),
                   Value => New_Attribute);
                Decl.Attributes := Variable_Element_Table.Last
-                 (In_Tree.Variable_Elements);
+                 (Shared.Variable_Elements);
             end;
          end if;
 
@@ -342,7 +331,7 @@ package body Prj.Proc is
       To         : in out Declarations;
       New_Loc    : Source_Ptr;
       Restricted : Boolean;
-      In_Tree    : Project_Tree_Ref)
+      Shared     : Shared_Project_Tree_Data_Access)
    is
       V1  : Variable_Id;
       V2  : Variable_Id      := No_Variable;
@@ -367,7 +356,7 @@ package body Prj.Proc is
 
          --  Copy the attribute
 
-         Var := In_Tree.Variable_Elements.Table (V1);
+         Var := Shared.Variable_Elements.Table (V1);
          V1  := Var.Next;
 
          --  Do not copy the value of attribute Linker_Options if Restricted
@@ -383,27 +372,27 @@ package body Prj.Proc is
          --  Change the location to New_Loc
 
          Var.Value.Location := New_Loc;
-         Variable_Element_Table.Increment_Last (In_Tree.Variable_Elements);
+         Variable_Element_Table.Increment_Last (Shared.Variable_Elements);
 
          --  Put in new declaration
 
          if To.Attributes = No_Variable then
             To.Attributes :=
-              Variable_Element_Table.Last (In_Tree.Variable_Elements);
+              Variable_Element_Table.Last (Shared.Variable_Elements);
          else
-            In_Tree.Variable_Elements.Table (V2).Next :=
-              Variable_Element_Table.Last (In_Tree.Variable_Elements);
+            Shared.Variable_Elements.Table (V2).Next :=
+              Variable_Element_Table.Last (Shared.Variable_Elements);
          end if;
 
-         V2 := Variable_Element_Table.Last (In_Tree.Variable_Elements);
-         In_Tree.Variable_Elements.Table (V2) := Var;
+         V2 := Variable_Element_Table.Last (Shared.Variable_Elements);
+         Shared.Variable_Elements.Table (V2) := Var;
       end loop;
 
       --  Then the associated array attributes
 
       A1 := From.Arrays;
       while A1 /= No_Array loop
-         Arr := In_Tree.Arrays.Table (A1);
+         Arr := Shared.Arrays.Table (A1);
          A1  := Arr.Next;
 
          if not Restricted
@@ -416,18 +405,18 @@ package body Prj.Proc is
             --  Remove the Next component
 
             Arr.Next := No_Array;
-            Array_Table.Increment_Last (In_Tree.Arrays);
+            Array_Table.Increment_Last (Shared.Arrays);
 
             --  Create new Array declaration
 
             if To.Arrays = No_Array then
-               To.Arrays := Array_Table.Last (In_Tree.Arrays);
+               To.Arrays := Array_Table.Last (Shared.Arrays);
             else
-               In_Tree.Arrays.Table (A2).Next :=
-                 Array_Table.Last (In_Tree.Arrays);
+               Shared.Arrays.Table (A2).Next :=
+                 Array_Table.Last (Shared.Arrays);
             end if;
 
-            A2 := Array_Table.Last (In_Tree.Arrays);
+            A2 := Array_Table.Last (Shared.Arrays);
 
             --  Don't store the array as its first element has not been set yet
 
@@ -439,7 +428,7 @@ package body Prj.Proc is
 
                --  Copy the array element
 
-               Elm := In_Tree.Array_Elements.Table (E1);
+               Elm := Shared.Array_Elements.Table (E1);
                E1 := Elm.Next;
 
                --  Remove the Next component
@@ -449,25 +438,25 @@ package body Prj.Proc is
                --  Change the location
 
                Elm.Value.Location := New_Loc;
-               Array_Element_Table.Increment_Last (In_Tree.Array_Elements);
+               Array_Element_Table.Increment_Last (Shared.Array_Elements);
 
                --  Create new array element
 
                if Arr.Value = No_Array_Element then
                   Arr.Value :=
-                    Array_Element_Table.Last (In_Tree.Array_Elements);
+                    Array_Element_Table.Last (Shared.Array_Elements);
                else
-                  In_Tree.Array_Elements.Table (E2).Next :=
-                    Array_Element_Table.Last (In_Tree.Array_Elements);
+                  Shared.Array_Elements.Table (E2).Next :=
+                    Array_Element_Table.Last (Shared.Array_Elements);
                end if;
 
-               E2 := Array_Element_Table.Last (In_Tree.Array_Elements);
-               In_Tree.Array_Elements.Table (E2) := Elm;
+               E2 := Array_Element_Table.Last (Shared.Array_Elements);
+               Shared.Array_Elements.Table (E2) := Elm;
             end loop;
 
             --  Finally, store the new array
 
-            In_Tree.Arrays.Table (A2) := Arr;
+            Shared.Arrays.Table (A2) := Arr;
          end if;
       end loop;
    end Copy_Package_Declarations;
@@ -499,7 +488,7 @@ package body Prj.Proc is
 
    function Expression
      (Project                : Project_Id;
-      In_Tree                : Project_Tree_Ref;
+      Shared                 : Shared_Project_Tree_Data_Access;
       From_Project_Node      : Project_Node_Id;
       From_Project_Node_Tree : Project_Node_Tree_Ref;
       Env                    : Prj.Tree.Environment;
@@ -553,25 +542,25 @@ package body Prj.Proc is
                   when List =>
 
                      String_Element_Table.Increment_Last
-                       (In_Tree.String_Elements);
+                       (Shared.String_Elements);
 
                      if Last = Nil_String then
 
                         --  This can happen in an expression like () & "toto"
 
                         Result.Values := String_Element_Table.Last
-                          (In_Tree.String_Elements);
+                          (Shared.String_Elements);
 
                      else
-                        In_Tree.String_Elements.Table
+                        Shared.String_Elements.Table
                           (Last).Next := String_Element_Table.Last
-                                       (In_Tree.String_Elements);
+                                       (Shared.String_Elements);
                      end if;
 
                      Last := String_Element_Table.Last
-                               (In_Tree.String_Elements);
+                               (Shared.String_Elements);
 
-                     In_Tree.String_Elements.Table (Last) :=
+                     Shared.String_Elements.Table (Last) :=
                        (Value         => String_Value_Of
                                            (The_Current_Term,
                                             From_Project_Node_Tree),
@@ -604,7 +593,7 @@ package body Prj.Proc is
 
                      Value := Expression
                        (Project                => Project,
-                        In_Tree                => In_Tree,
+                        Shared                 => Shared,
                         From_Project_Node      => From_Project_Node,
                         From_Project_Node_Tree => From_Project_Node_Tree,
                         Env                    => Env,
@@ -614,26 +603,25 @@ package body Prj.Proc is
                             (String_Node, From_Project_Node_Tree),
                         Kind                   => Single);
                      String_Element_Table.Increment_Last
-                       (In_Tree.String_Elements);
+                       (Shared.String_Elements);
 
                      if Result.Values = Nil_String then
 
                         --  This literal string list is the first term in a
                         --  string list expression
 
-                        Result.Values :=
-                          String_Element_Table.Last (In_Tree.String_Elements);
+                        Result.Values := String_Element_Table.Last
+                          (Shared.String_Elements);
 
                      else
-                        In_Tree.String_Elements.Table
-                          (Last).Next :=
-                          String_Element_Table.Last (In_Tree.String_Elements);
+                        Shared.String_Elements.Table (Last).Next :=
+                          String_Element_Table.Last (Shared.String_Elements);
                      end if;
 
-                     Last :=
-                       String_Element_Table.Last (In_Tree.String_Elements);
+                     Last := String_Element_Table.Last
+                       (Shared.String_Elements);
 
-                     In_Tree.String_Elements.Table (Last) :=
+                     Shared.String_Elements.Table (Last) :=
                        (Value    => Value.Value,
                         Display_Value => No_Name,
                         Location => Value.Location,
@@ -654,7 +642,7 @@ package body Prj.Proc is
                         Value :=
                           Expression
                             (Project                => Project,
-                             In_Tree                => In_Tree,
+                             Shared                 => Shared,
                              From_Project_Node      => From_Project_Node,
                              From_Project_Node_Tree => From_Project_Node_Tree,
                              Env                    => Env,
@@ -665,12 +653,12 @@ package body Prj.Proc is
                              Kind                   => Single);
 
                         String_Element_Table.Increment_Last
-                          (In_Tree.String_Elements);
-                        In_Tree.String_Elements.Table (Last).Next :=
-                          String_Element_Table.Last (In_Tree.String_Elements);
-                        Last :=
-                          String_Element_Table.Last (In_Tree.String_Elements);
-                        In_Tree.String_Elements.Table (Last) :=
+                          (Shared.String_Elements);
+                        Shared.String_Elements.Table (Last).Next :=
+                          String_Element_Table.Last (Shared.String_Elements);
+                        Last := String_Element_Table.Last
+                          (Shared.String_Elements);
+                        Shared.String_Elements.Table (Last) :=
                           (Value    => Value.Value,
                            Display_Value => No_Name,
                            Location => Value.Location,
@@ -721,11 +709,11 @@ package body Prj.Proc is
                      The_Package := The_Project.Decl.Packages;
 
                      while The_Package /= No_Package
-                       and then In_Tree.Packages.Table
-                                  (The_Package).Name /= The_Name
+                       and then Shared.Packages.Table (The_Package).Name /=
+                          The_Name
                      loop
                         The_Package :=
-                          In_Tree.Packages.Table (The_Package).Next;
+                          Shared.Packages.Table (The_Package).Next;
                      end loop;
 
                      pragma Assert
@@ -762,22 +750,20 @@ package body Prj.Proc is
                                                         N_Variable_Reference
                         then
                            The_Variable_Id :=
-                             In_Tree.Packages.Table
+                             Shared.Packages.Table
                                (The_Package).Decl.Variables;
                         else
                            The_Variable_Id :=
-                             In_Tree.Packages.Table
+                             Shared.Packages.Table
                                (The_Package).Decl.Attributes;
                         end if;
 
                         while The_Variable_Id /= No_Variable
-                          and then
-                            In_Tree.Variable_Elements.Table
-                              (The_Variable_Id).Name /= The_Name
+                          and then Shared.Variable_Elements.Table
+                            (The_Variable_Id).Name /= The_Name
                         loop
-                           The_Variable_Id :=
-                             In_Tree.Variable_Elements.Table
-                               (The_Variable_Id).Next;
+                           The_Variable_Id := Shared.Variable_Elements.Table
+                             (The_Variable_Id).Next;
                         end loop;
 
                      end if;
@@ -795,12 +781,11 @@ package body Prj.Proc is
                         end if;
 
                         while The_Variable_Id /= No_Variable
-                          and then
-                          In_Tree.Variable_Elements.Table
+                          and then Shared.Variable_Elements.Table
                             (The_Variable_Id).Name /= The_Name
                         loop
                            The_Variable_Id :=
-                             In_Tree.Variable_Elements.Table
+                             Shared.Variable_Elements.Table
                                (The_Variable_Id).Next;
                         end loop;
 
@@ -810,8 +795,7 @@ package body Prj.Proc is
                                       "variable or attribute not found");
 
                      The_Variable :=
-                       In_Tree.Variable_Elements.Table
-                                                    (The_Variable_Id).Value;
+                       Shared.Variable_Elements.Table (The_Variable_Id).Value;
 
                   else
 
@@ -824,22 +808,22 @@ package body Prj.Proc is
 
                      begin
                         if The_Package /= No_Package then
-                           The_Array :=
-                             In_Tree.Packages.Table (The_Package).Decl.Arrays;
+                           The_Array := Shared.Packages.Table
+                             (The_Package).Decl.Arrays;
                         else
                            The_Array := The_Project.Decl.Arrays;
                         end if;
 
                         while The_Array /= No_Array
-                          and then In_Tree.Arrays.Table
-                                     (The_Array).Name /= The_Name
+                          and then Shared.Arrays.Table (The_Array).Name /=
+                          The_Name
                         loop
-                           The_Array := In_Tree.Arrays.Table (The_Array).Next;
+                           The_Array := Shared.Arrays.Table (The_Array).Next;
                         end loop;
 
                         if The_Array /= No_Array then
                            The_Element :=
-                             In_Tree.Arrays.Table (The_Array).Value;
+                             Shared.Arrays.Table (The_Array).Value;
                            Array_Index :=
                              Get_Attribute_Index
                                (From_Project_Node_Tree,
@@ -847,19 +831,19 @@ package body Prj.Proc is
                                 Index);
 
                            while The_Element /= No_Array_Element
-                             and then In_Tree.Array_Elements.Table
+                             and then Shared.Array_Elements.Table
                                         (The_Element).Index /= Array_Index
                            loop
                               The_Element :=
-                                In_Tree.Array_Elements.Table
+                                Shared.Array_Elements.Table
                                   (The_Element).Next;
                            end loop;
 
                         end if;
 
                         if The_Element /= No_Array_Element then
-                           The_Variable :=
-                             In_Tree.Array_Elements.Table (The_Element).Value;
+                           The_Variable := Shared.Array_Elements.Table
+                             (The_Element).Value;
 
                         else
                            if Expression_Kind_Of
@@ -923,7 +907,7 @@ package body Prj.Proc is
 
                            when Single =>
                               String_Element_Table.Increment_Last
-                                (In_Tree.String_Elements);
+                                (Shared.String_Elements);
 
                               if Last = Nil_String then
 
@@ -932,20 +916,19 @@ package body Prj.Proc is
 
                                  Result.Values :=
                                    String_Element_Table.Last
-                                     (In_Tree.String_Elements);
+                                     (Shared.String_Elements);
 
                               else
-                                 In_Tree.String_Elements.Table
-                                   (Last).Next :=
+                                 Shared.String_Elements.Table (Last).Next :=
                                      String_Element_Table.Last
-                                       (In_Tree.String_Elements);
+                                       (Shared.String_Elements);
                               end if;
 
                               Last :=
                                 String_Element_Table.Last
-                                  (In_Tree.String_Elements);
+                                  (Shared.String_Elements);
 
-                              In_Tree.String_Elements.Table (Last) :=
+                              Shared.String_Elements.Table (Last) :=
                                 (Value         => The_Variable.Value,
                                  Display_Value => No_Name,
                                  Location      => Location_Of
@@ -964,30 +947,29 @@ package body Prj.Proc is
                               begin
                                  while The_List /= Nil_String loop
                                     String_Element_Table.Increment_Last
-                                      (In_Tree.String_Elements);
+                                      (Shared.String_Elements);
 
                                     if Last = Nil_String then
                                        Result.Values :=
                                          String_Element_Table.Last
-                                           (In_Tree.
-                                                String_Elements);
+                                           (Shared.String_Elements);
 
                                     else
-                                       In_Tree.
+                                       Shared.
                                          String_Elements.Table (Last).Next :=
                                          String_Element_Table.Last
-                                           (In_Tree.
-                                                String_Elements);
+                                           (Shared.String_Elements);
 
                                     end if;
 
                                     Last :=
                                       String_Element_Table.Last
-                                        (In_Tree.String_Elements);
+                                        (Shared.String_Elements);
 
-                                    In_Tree.String_Elements.Table (Last) :=
+                                    Shared.String_Elements.Table
+                                      (Last) :=
                                       (Value         =>
-                                         In_Tree.String_Elements.Table
+                                         Shared.String_Elements.Table
                                            (The_List).Value,
                                        Display_Value => No_Name,
                                        Location      =>
@@ -998,8 +980,7 @@ package body Prj.Proc is
                                        Next         => Nil_String,
                                        Index        => 0);
 
-                                    The_List :=
-                                      In_Tree. String_Elements.Table
+                                    The_List := Shared.String_Elements.Table
                                         (The_List).Next;
                                  end loop;
                               end;
@@ -1034,7 +1015,7 @@ package body Prj.Proc is
                   if Present (Default_Node) then
                      Def_Var := Expression
                        (Project                => Project,
-                        In_Tree                => In_Tree,
+                        Shared                 => Shared,
                         From_Project_Node      => From_Project_Node,
                         From_Project_Node_Tree => From_Project_Node_Tree,
                         Env                    => Env,
@@ -1189,29 +1170,28 @@ package body Prj.Proc is
                      when List =>
                         if not Ext_List or else Str_List /= null then
                            String_Element_Table.Increment_Last
-                             (In_Tree.String_Elements);
+                             (Shared.String_Elements);
 
                            if Last = Nil_String then
                               Result.Values :=
                                 String_Element_Table.Last
-                                  (In_Tree.String_Elements);
+                                  (Shared.String_Elements);
 
                            else
-                              In_Tree.String_Elements.Table (Last).Next :=
-                                String_Element_Table.Last
-                                  (In_Tree.String_Elements);
+                              Shared.String_Elements.Table (Last).Next
+                                := String_Element_Table.Last
+                                  (Shared.String_Elements);
                            end if;
 
-                           Last :=
-                             String_Element_Table.Last
-                               (In_Tree.String_Elements);
+                           Last := String_Element_Table.Last
+                             (Shared.String_Elements);
 
                            if Ext_List then
                               for Ind in Str_List'Range loop
                                  Name_Len := 0;
                                  Add_Str_To_Name_Buffer (Str_List (Ind).all);
                                  Value := Name_Find;
-                                 In_Tree.String_Elements.Table (Last) :=
+                                 Shared.String_Elements.Table (Last) :=
                                    (Value         => Value,
                                     Display_Value => No_Name,
                                     Location      =>
@@ -1224,19 +1204,17 @@ package body Prj.Proc is
 
                                  if Ind /= Str_List'Last then
                                     String_Element_Table.Increment_Last
-                                      (In_Tree.String_Elements);
-                                    In_Tree.String_Elements.Table
-                                                              (Last).Next :=
+                                      (Shared.String_Elements);
+                                    Shared.String_Elements.Table (Last).Next :=
                                         String_Element_Table.Last
-                                          (In_Tree.String_Elements);
-                                    Last :=
-                                      String_Element_Table.Last
-                                        (In_Tree.String_Elements);
+                                          (Shared.String_Elements);
+                                    Last := String_Element_Table.Last
+                                        (Shared.String_Elements);
                                  end if;
                               end loop;
 
                            else
-                              In_Tree.String_Elements.Table (Last) :=
+                              Shared.String_Elements.Table (Last) :=
                                 (Value         => Value,
                                  Display_Value => No_Name,
                                  Location      =>
@@ -1337,7 +1315,7 @@ package body Prj.Proc is
 
    function Package_From
      (Project   : Project_Id;
-      In_Tree   : Project_Tree_Ref;
+      Shared    : Shared_Project_Tree_Data_Access;
       With_Name : Name_Id) return Package_Id
    is
       Result : Package_Id := Project.Decl.Packages;
@@ -1346,9 +1324,9 @@ package body Prj.Proc is
       --  Check the name of each existing package of Project
 
       while Result /= No_Package
-        and then In_Tree.Packages.Table (Result).Name /= With_Name
+        and then Shared.Packages.Table (Result).Name /= With_Name
       loop
-         Result := In_Tree.Packages.Table (Result).Next;
+         Result := Shared.Packages.Table (Result).Next;
       end loop;
 
       if Result = No_Package then
@@ -1412,9 +1390,11 @@ package body Prj.Proc is
       Env                    : Prj.Tree.Environment;
       Pkg                    : Package_Id;
       Item                   : Project_Node_Id;
-      Child_Env              : in out Prj.Tree.Environment;
-      Can_Modify_Child_Env   : Boolean)
+      Child_Env              : in out Prj.Tree.Environment)
    is
+      Shared : constant Shared_Project_Tree_Data_Access :=
+        In_Tree.Shared;
+
       procedure Check_Or_Set_Typed_Variable
         (Value       : in out Variable_Value;
          Declaration : Project_Node_Id);
@@ -1532,11 +1512,11 @@ package body Prj.Proc is
 
             --  Create the new package
 
-            Package_Table.Increment_Last (In_Tree.Packages);
+            Package_Table.Increment_Last (Shared.Packages);
 
             declare
                New_Pkg         : constant Package_Id :=
-                                   Package_Table.Last (In_Tree.Packages);
+                                  Package_Table.Last (Shared.Packages);
                The_New_Package : Package_Element;
 
                Project_Of_Renamed_Package : constant Project_Node_Id :=
@@ -1552,15 +1532,15 @@ package body Prj.Proc is
 
                if Pkg /= No_Package then
                   The_New_Package.Next :=
-                    In_Tree.Packages.Table (Pkg).Decl.Packages;
-                  In_Tree.Packages.Table (Pkg).Decl.Packages := New_Pkg;
+                    Shared.Packages.Table (Pkg).Decl.Packages;
+                  Shared.Packages.Table (Pkg).Decl.Packages := New_Pkg;
 
                else
                   The_New_Package.Next  := Project.Decl.Packages;
                   Project.Decl.Packages := New_Pkg;
                end if;
 
-               In_Tree.Packages.Table (New_Pkg) := The_New_Package;
+               Shared.Packages.Table (New_Pkg) := The_New_Package;
 
                if Present (Project_Of_Renamed_Package) then
 
@@ -1576,7 +1556,7 @@ package body Prj.Proc is
 
                      Renamed_Package : constant Package_Id :=
                        Package_From
-                         (Renamed_Project, In_Tree,
+                         (Renamed_Project, Shared,
                           Name_Of (Current_Item, Node_Tree));
 
                   begin
@@ -1586,11 +1566,11 @@ package body Prj.Proc is
                      --  declaration.
 
                      Copy_Package_Declarations
-                       (From => In_Tree.Packages.Table (Renamed_Package).Decl,
-                        To   => In_Tree.Packages.Table (New_Pkg).Decl,
+                       (From => Shared.Packages.Table (Renamed_Package).Decl,
+                        To   => Shared.Packages.Table (New_Pkg).Decl,
                         New_Loc    => Location_Of (Current_Item, Node_Tree),
                         Restricted => False,
-                        In_Tree    => In_Tree);
+                        Shared     => Shared);
                   end;
 
                else
@@ -1600,8 +1580,8 @@ package body Prj.Proc is
                     (Project,
                      Project.Name,
                      Name_Id (Project.Directory.Name),
-                     In_Tree,
-                     In_Tree.Packages.Table (New_Pkg).Decl,
+                     Shared,
+                     Shared.Packages.Table (New_Pkg).Decl,
                      First_Attribute_Of
                        (Package_Id_Of (Current_Item, Node_Tree)),
                      Project_Level => False);
@@ -1619,8 +1599,7 @@ package body Prj.Proc is
                   Pkg                    => New_Pkg,
                   Item                   =>
                     First_Declarative_Item_Of (Current_Item, Node_Tree),
-                  Child_Env              => Child_Env,
-                  Can_Modify_Child_Env   => Can_Modify_Child_Env);
+                  Child_Env              => Child_Env);
             end;
          end if;
       end Process_Package_Declaration;
@@ -1683,35 +1662,35 @@ package body Prj.Proc is
          --  declared.
 
          if Pkg /= No_Package then
-            New_Array := In_Tree.Packages.Table (Pkg).Decl.Arrays;
+            New_Array := Shared.Packages.Table (Pkg).Decl.Arrays;
          else
             New_Array := Project.Decl.Arrays;
          end if;
 
          while New_Array /= No_Array
-           and then In_Tree.Arrays.Table (New_Array).Name /= Current_Item_Name
+           and then Shared.Arrays.Table (New_Array).Name /= Current_Item_Name
          loop
-            New_Array := In_Tree.Arrays.Table (New_Array).Next;
+            New_Array := Shared.Arrays.Table (New_Array).Next;
          end loop;
 
          --  If the attribute has never been declared add new entry in the
          --  arrays of the project/package and link it.
 
          if New_Array = No_Array then
-            Array_Table.Increment_Last (In_Tree.Arrays);
-            New_Array := Array_Table.Last (In_Tree.Arrays);
+            Array_Table.Increment_Last (Shared.Arrays);
+            New_Array := Array_Table.Last (Shared.Arrays);
 
             if Pkg /= No_Package then
-               In_Tree.Arrays.Table (New_Array) :=
+               Shared.Arrays.Table (New_Array) :=
                  (Name     => Current_Item_Name,
                   Location => Current_Location,
                   Value    => No_Array_Element,
-                  Next     => In_Tree.Packages.Table (Pkg).Decl.Arrays);
+                  Next     => Shared.Packages.Table (Pkg).Decl.Arrays);
 
-               In_Tree.Packages.Table (Pkg).Decl.Arrays := New_Array;
+               Shared.Packages.Table (Pkg).Decl.Arrays := New_Array;
 
             else
-               In_Tree.Arrays.Table (New_Array) :=
+               Shared.Arrays.Table (New_Array) :=
                  (Name     => Current_Item_Name,
                   Location => Current_Location,
                   Value    => No_Array_Element,
@@ -1753,23 +1732,23 @@ package body Prj.Proc is
             pragma Assert (Orig_Package /= No_Package,
                            "original package not found");
 
-            while In_Tree.Packages.Table
-                    (Orig_Package).Name /= Orig_Package_Name
+            while Shared.Packages.Table
+              (Orig_Package).Name /= Orig_Package_Name
             loop
-               Orig_Package := In_Tree.Packages.Table (Orig_Package).Next;
+               Orig_Package := Shared.Packages.Table (Orig_Package).Next;
                pragma Assert (Orig_Package /= No_Package,
                               "original package not found");
             end loop;
 
-            Orig_Array := In_Tree.Packages.Table (Orig_Package).Decl.Arrays;
+            Orig_Array := Shared.Packages.Table (Orig_Package).Decl.Arrays;
          end if;
 
          --  Now look for the array
 
          while Orig_Array /= No_Array
-           and then In_Tree.Arrays.Table (Orig_Array).Name /= Current_Item_Name
+           and then Shared.Arrays.Table (Orig_Array).Name /= Current_Item_Name
          loop
-            Orig_Array := In_Tree.Arrays.Table (Orig_Array).Next;
+            Orig_Array := Shared.Arrays.Table (Orig_Array).Next;
          end loop;
 
          if Orig_Array = No_Array then
@@ -1780,7 +1759,7 @@ package body Prj.Proc is
                Project);
 
          else
-            Orig_Element := In_Tree.Arrays.Table (Orig_Array).Value;
+            Orig_Element := Shared.Arrays.Table (Orig_Array).Value;
 
             --  Copy each array element
 
@@ -1793,22 +1772,22 @@ package body Prj.Proc is
                   --  And there is no array element declared yet, create a new
                   --  first array element.
 
-                  if In_Tree.Arrays.Table (New_Array).Value =
+                  if Shared.Arrays.Table (New_Array).Value =
                     No_Array_Element
                   then
                      Array_Element_Table.Increment_Last
-                       (In_Tree.Array_Elements);
+                       (Shared.Array_Elements);
                      New_Element := Array_Element_Table.Last
-                       (In_Tree.Array_Elements);
-                     In_Tree.Arrays.Table (New_Array).Value := New_Element;
+                       (Shared.Array_Elements);
+                     Shared.Arrays.Table (New_Array).Value := New_Element;
                      Next_Element := No_Array_Element;
 
                      --  Otherwise, the new element is the first
 
                   else
-                     New_Element := In_Tree.Arrays. Table (New_Array).Value;
+                     New_Element := Shared.Arrays.Table (New_Array).Value;
                      Next_Element :=
-                       In_Tree.Array_Elements.Table (New_Element).Next;
+                       Shared.Array_Elements.Table (New_Element).Next;
                   end if;
 
                   --  Otherwise, reuse an existing element, or create
@@ -1816,33 +1795,33 @@ package body Prj.Proc is
 
                else
                   Next_Element :=
-                    In_Tree.Array_Elements.Table (Prev_Element).Next;
+                    Shared.Array_Elements.Table (Prev_Element).Next;
 
                   if Next_Element = No_Array_Element then
                      Array_Element_Table.Increment_Last
-                       (In_Tree.Array_Elements);
-                     New_Element :=
-                       Array_Element_Table.Last (In_Tree.Array_Elements);
-                     In_Tree.Array_Elements.Table (Prev_Element).Next :=
+                       (Shared.Array_Elements);
+                     New_Element := Array_Element_Table.Last
+                       (Shared.Array_Elements);
+                     Shared.Array_Elements.Table (Prev_Element).Next :=
                        New_Element;
 
                   else
                      New_Element := Next_Element;
                      Next_Element :=
-                       In_Tree.Array_Elements.Table (New_Element).Next;
+                       Shared.Array_Elements.Table (New_Element).Next;
                   end if;
                end if;
 
                --  Copy the value of the element
 
-               In_Tree.Array_Elements.Table (New_Element) :=
-                 In_Tree.Array_Elements.Table (Orig_Element);
-               In_Tree.Array_Elements.Table (New_Element).Value.Project :=
-                 Project;
+               Shared.Array_Elements.Table (New_Element) :=
+                 Shared.Array_Elements.Table (Orig_Element);
+               Shared.Array_Elements.Table (New_Element).Value.Project
+                 := Project;
 
                --  Adjust the Next link
 
-               In_Tree.Array_Elements.Table (New_Element).Next := Next_Element;
+               Shared.Array_Elements.Table (New_Element).Next := Next_Element;
 
                --  Adjust the previous id for the next element
 
@@ -1850,15 +1829,13 @@ package body Prj.Proc is
 
                --  Go to the next element in the original array
 
-               Orig_Element :=
-                 In_Tree.Array_Elements.Table (Orig_Element).Next;
+               Orig_Element := Shared.Array_Elements.Table (Orig_Element).Next;
             end loop;
 
             --  Make sure that the array ends here, in case there previously a
             --  greater number of elements.
 
-            In_Tree.Array_Elements.Table (New_Element).Next :=
-              No_Array_Element;
+            Shared.Array_Elements.Table (New_Element).Next := No_Array_Element;
          end if;
       end Process_Associative_Array;
 
@@ -1891,15 +1868,15 @@ package body Prj.Proc is
          --  Look for the array in the appropriate list
 
          if Pkg /= No_Package then
-            The_Array := In_Tree.Packages.Table (Pkg).Decl.Arrays;
+            The_Array := Shared.Packages.Table (Pkg).Decl.Arrays;
          else
             The_Array := Project.Decl.Arrays;
          end if;
 
          while The_Array /= No_Array
-           and then In_Tree.Arrays.Table (The_Array).Name /= Name
+           and then Shared.Arrays.Table (The_Array).Name /= Name
          loop
-            The_Array := In_Tree.Arrays.Table (The_Array).Next;
+            The_Array := Shared.Arrays.Table (The_Array).Next;
          end loop;
 
          --  If the array cannot be found, create a new entry in the list.
@@ -1907,20 +1884,20 @@ package body Prj.Proc is
          --  element will be created automatically later
 
          if The_Array = No_Array then
-            Array_Table.Increment_Last (In_Tree.Arrays);
-            The_Array := Array_Table.Last (In_Tree.Arrays);
+            Array_Table.Increment_Last (Shared.Arrays);
+            The_Array := Array_Table.Last (Shared.Arrays);
 
             if Pkg /= No_Package then
-               In_Tree.Arrays.Table (The_Array) :=
+               Shared.Arrays.Table (The_Array) :=
                  (Name     => Name,
                   Location => Current_Location,
                   Value    => No_Array_Element,
-                  Next     => In_Tree.Packages.Table (Pkg).Decl.Arrays);
+                  Next     => Shared.Packages.Table (Pkg).Decl.Arrays);
 
-               In_Tree.Packages.Table (Pkg).Decl.Arrays := The_Array;
+               Shared.Packages.Table (Pkg).Decl.Arrays := The_Array;
 
             else
-               In_Tree.Arrays.Table (The_Array) :=
+               Shared.Arrays.Table (The_Array) :=
                  (Name     => Name,
                   Location => Current_Location,
                   Value    => No_Array_Element,
@@ -1930,7 +1907,7 @@ package body Prj.Proc is
             end if;
 
          else
-            Elem := In_Tree.Arrays.Table (The_Array).Value;
+            Elem := Shared.Arrays.Table (The_Array).Value;
          end if;
 
          --  Look in the list, if any, to find an element with the same index
@@ -1938,11 +1915,11 @@ package body Prj.Proc is
 
          while Elem /= No_Array_Element
            and then
-             (In_Tree.Array_Elements.Table (Elem).Index /= Index_Name
+             (Shared.Array_Elements.Table (Elem).Index /= Index_Name
                or else
-                 In_Tree.Array_Elements.Table (Elem).Src_Index /= Source_Index)
+                 Shared.Array_Elements.Table (Elem).Src_Index /= Source_Index)
          loop
-            Elem := In_Tree.Array_Elements.Table (Elem).Next;
+            Elem := Shared.Array_Elements.Table (Elem).Next;
          end loop;
 
          --  If no such element were found, create a new one
@@ -1950,29 +1927,29 @@ package body Prj.Proc is
          --  proper value.
 
          if Elem = No_Array_Element then
-            Array_Element_Table.Increment_Last (In_Tree.Array_Elements);
-            Elem := Array_Element_Table.Last (In_Tree.Array_Elements);
+            Array_Element_Table.Increment_Last (Shared.Array_Elements);
+            Elem := Array_Element_Table.Last (Shared.Array_Elements);
 
-            In_Tree.Array_Elements.Table
+            Shared.Array_Elements.Table
               (Elem) :=
               (Index                => Index_Name,
                Src_Index            => Source_Index,
                Index_Case_Sensitive =>
                   not Case_Insensitive (Current, Node_Tree),
                Value                => New_Value,
-               Next                 => In_Tree.Arrays.Table (The_Array).Value);
+               Next                 => Shared.Arrays.Table (The_Array).Value);
 
-            In_Tree.Arrays.Table (The_Array).Value := Elem;
+            Shared.Arrays.Table (The_Array).Value := Elem;
 
          else
             --  An element with the same index already exists, just replace its
             --  value with the new one.
 
-            In_Tree.Array_Elements.Table (Elem).Value := New_Value;
+            Shared.Array_Elements.Table (Elem).Value := New_Value;
          end if;
 
          if Name = Snames.Name_External then
-            if Can_Modify_Child_Env then
+            if In_Tree.Is_Root_Tree then
                Add (Child_Env.External,
                     External_Name => Get_Name_String (Index_Name),
                     Value         => Get_Name_String (New_Value.Value),
@@ -2015,14 +1992,14 @@ package body Prj.Proc is
 
          if Is_Attribute then
             if Pkg /= No_Package then
-               Var := In_Tree.Packages.Table (Pkg).Decl.Attributes;
+               Var := Shared.Packages.Table (Pkg).Decl.Attributes;
             else
                Var := Project.Decl.Attributes;
             end if;
 
          else
             if Pkg /= No_Package then
-               Var := In_Tree.Packages.Table (Pkg).Decl.Variables;
+               Var := Shared.Packages.Table (Pkg).Decl.Variables;
             else
                Var := Project.Decl.Variables;
             end if;
@@ -2031,9 +2008,9 @@ package body Prj.Proc is
          --  Loop through the list, to find if it has already been declared.
 
          while Var /= No_Variable
-           and then In_Tree.Variable_Elements.Table (Var).Name /= Name
+           and then Shared.Variable_Elements.Table (Var).Name /= Name
          loop
-            Var := In_Tree.Variable_Elements.Table (Var).Next;
+            Var := Shared.Variable_Elements.Table (Var).Next;
          end loop;
 
          --  If it has not been declared, create a new entry in the list
@@ -2047,20 +2024,20 @@ package body Prj.Proc is
               (not Is_Attribute,
                "illegal attribute declaration for " & Get_Name_String (Name));
 
-            Variable_Element_Table.Increment_Last (In_Tree.Variable_Elements);
-            Var := Variable_Element_Table.Last (In_Tree.Variable_Elements);
+            Variable_Element_Table.Increment_Last (Shared.Variable_Elements);
+            Var := Variable_Element_Table.Last (Shared.Variable_Elements);
 
             --  Put the new variable in the appropriate list
 
             if Pkg /= No_Package then
-               In_Tree.Variable_Elements.Table (Var) :=
-                 (Next   => In_Tree.Packages.Table (Pkg).Decl.Variables,
+               Shared.Variable_Elements.Table (Var) :=
+                 (Next   => Shared.Packages.Table (Pkg).Decl.Variables,
                   Name   => Name,
                   Value  => New_Value);
-               In_Tree.Packages.Table (Pkg).Decl.Variables := Var;
+               Shared.Packages.Table (Pkg).Decl.Variables := Var;
 
             else
-               In_Tree.Variable_Elements.Table (Var) :=
+               Shared.Variable_Elements.Table (Var) :=
                  (Next   => Project.Decl.Variables,
                   Name   => Name,
                   Value  => New_Value);
@@ -2071,7 +2048,7 @@ package body Prj.Proc is
             --  change the value.
 
          else
-            In_Tree.Variable_Elements.Table (Var).Value := New_Value;
+            Shared.Variable_Elements.Table (Var).Value := New_Value;
          end if;
       end Process_Expression_Variable_Decl;
 
@@ -2083,7 +2060,7 @@ package body Prj.Proc is
          New_Value : Variable_Value :=
                        Expression
                          (Project                => Project,
-                          In_Tree                => In_Tree,
+                          Shared                 => Shared,
                           From_Project_Node      => From_Project_Node,
                           From_Project_Node_Tree => Node_Tree,
                           Env                    => Env,
@@ -2173,7 +2150,7 @@ package body Prj.Proc is
                Name :=
                  Name_Of
                    (Package_Node_Of (Variable_Node, Node_Tree), Node_Tree);
-               The_Package := Package_From (The_Project, In_Tree, Name);
+               The_Package := Package_From (The_Project, Shared, Name);
             end if;
 
             Name := Name_Of (Variable_Node, Node_Tree);
@@ -2183,11 +2160,11 @@ package body Prj.Proc is
             if The_Package /= No_Package then
                Name := Name_Of (Variable_Node, Node_Tree);
 
-               Var_Id := In_Tree.Packages.Table (The_Package).Decl.Variables;
+               Var_Id := Shared.Packages.Table (The_Package).Decl.Variables;
                while Var_Id /= No_Variable
-                 and then In_Tree.Variable_Elements.Table (Var_Id).Name /= Name
+                 and then Shared.Variable_Elements.Table (Var_Id).Name /= Name
                loop
-                  Var_Id := In_Tree.Variable_Elements.Table (Var_Id).Next;
+                  Var_Id := Shared.Variable_Elements.Table (Var_Id).Next;
                end loop;
             end if;
 
@@ -2199,9 +2176,9 @@ package body Prj.Proc is
             then
                Var_Id := The_Project.Decl.Variables;
                while Var_Id /= No_Variable
-                 and then In_Tree.Variable_Elements.Table (Var_Id).Name /= Name
+                 and then Shared.Variable_Elements.Table (Var_Id).Name /= Name
                loop
-                  Var_Id := In_Tree.Variable_Elements.Table (Var_Id).Next;
+                  Var_Id := Shared.Variable_Elements.Table (Var_Id).Next;
                end loop;
             end if;
 
@@ -2217,7 +2194,7 @@ package body Prj.Proc is
 
             --  Get the case variable
 
-            The_Variable := In_Tree.Variable_Elements. Table (Var_Id).Value;
+            The_Variable := Shared.Variable_Elements. Table (Var_Id).Value;
 
             if The_Variable.Kind /= Single then
 
@@ -2270,15 +2247,14 @@ package body Prj.Proc is
 
          if Present (Decl_Item) then
             Process_Declarative_Items
-              (Project              => Project,
-               In_Tree              => In_Tree,
-               From_Project_Node    => From_Project_Node,
-               Node_Tree            => Node_Tree,
-               Env                  => Env,
-               Pkg                  => Pkg,
-               Item                 => Decl_Item,
-               Child_Env            => Child_Env,
-               Can_Modify_Child_Env => Can_Modify_Child_Env);
+              (Project                => Project,
+               In_Tree                => In_Tree,
+               From_Project_Node      => From_Project_Node,
+               Node_Tree              => Node_Tree,
+               Env                    => Env,
+               Pkg                    => Pkg,
+               Item                   => Decl_Item,
+               Child_Env              => Child_Env);
          end if;
       end Process_Case_Construction;
 
@@ -2333,8 +2309,6 @@ package body Prj.Proc is
       Env                    : in out Prj.Tree.Environment;
       Reset_Tree             : Boolean := True)
    is
-      Child_Env : Prj.Tree.Environment;
-
    begin
       if Reset_Tree then
 
@@ -2350,19 +2324,13 @@ package body Prj.Proc is
 
       Debug_Increase_Indent ("Process tree, phase 1");
 
-      Initialize_And_Copy (Child_Env, Copy_From => Env);
-
       Recursive_Process
         (Project                => Project,
          In_Tree                => In_Tree,
          From_Project_Node      => From_Project_Node,
          From_Project_Node_Tree => From_Project_Node_Tree,
          Env                    => Env,
-         Extended_By            => No_Project,
-         Child_Env              => Child_Env,
-         Is_Root_Project        => True);
-
-      Free (Child_Env);
+         Extended_By            => No_Project);
 
       Success :=
         Total_Errors_Detected = 0
@@ -2397,7 +2365,7 @@ package body Prj.Proc is
    begin
       Success := True;
 
-      Debug_Increase_Indent ("Process tree, phase 2");
+      Debug_Increase_Indent ("Process tree, phase 2", Project.Name);
 
       if Project /= No_Project then
          Check (In_Tree, Project, From_Project_Node_Tree, Env.Flags);
@@ -2498,10 +2466,15 @@ package body Prj.Proc is
       From_Project_Node      : Project_Node_Id;
       From_Project_Node_Tree : Project_Node_Tree_Ref;
       Env                    : in out Prj.Tree.Environment;
-      Extended_By            : Project_Id;
-      Child_Env              : in out Prj.Tree.Environment;
-      Is_Root_Project        : Boolean)
+      Extended_By            : Project_Id)
    is
+      Shared : constant Shared_Project_Tree_Data_Access :=
+        In_Tree.Shared;
+
+      Child_Env              : Prj.Tree.Environment;
+      --  Only used for the root aggregate project (if any). This is left
+      --  uninitialized otherwise.
+
       procedure Process_Imported_Projects
         (Imported     : in out Project_List;
          Limited_With : Boolean);
@@ -2553,9 +2526,7 @@ package body Prj.Proc is
                       (With_Clause, From_Project_Node_Tree),
                   From_Project_Node_Tree => From_Project_Node_Tree,
                   Env                    => Env,
-                  Extended_By            => No_Project,
-                  Child_Env              => Child_Env,
-                  Is_Root_Project        => False);
+                  Extended_By            => No_Project);
 
                --  Imported is the id of the last imported project. If
                --  it is nil, then this imported project is our first.
@@ -2585,7 +2556,7 @@ package body Prj.Proc is
 
       procedure Process_Aggregated_Projects is
          List : Aggregated_Project_List;
-         Loaded_Tree : Prj.Tree.Project_Node_Id;
+         Loaded_Project : Prj.Tree.Project_Node_Id;
          Success     : Boolean := True;
       begin
          if Project.Qualifier /= Aggregate then
@@ -2604,25 +2575,46 @@ package body Prj.Proc is
          while Success and then List /= null loop
             Prj.Part.Parse
               (In_Tree           => From_Project_Node_Tree,
-               Project           => Loaded_Tree,
+               Project           => Loaded_Project,
                Project_File_Name => Get_Name_String (List.Path),
                Errout_Handling   => Prj.Part.Never_Finalize,
                Current_Directory => Get_Name_String (Project.Directory.Name),
                Is_Config_File    => False,
                Env               => Child_Env);
 
-            Success := not Prj.Tree.No (Loaded_Tree);
+            Success := not Prj.Tree.No (Loaded_Project);
 
             if Success then
-               Recursive_Process
-                 (In_Tree                => In_Tree,
-                  Project                => List.Project,
-                  From_Project_Node      => Loaded_Tree,
-                  From_Project_Node_Tree => From_Project_Node_Tree,
-                  Env                    => Child_Env,
-                  Extended_By            => No_Project,
-                  Child_Env              => Child_Env,
-                  Is_Root_Project        => False);
+               List.Tree := new Project_Tree_Data (Is_Root_Tree => False);
+               Prj.Initialize (List.Tree);
+               List.Tree.Shared := In_Tree.Shared;
+
+               --  We can only do the phase 1 of the processing, since we do
+               --  not have access to the configuration file yet (this is
+               --  called when doing phase 1 of the processing for the root
+               --  aggregate project).
+
+               if In_Tree.Is_Root_Tree then
+                  Process_Project_Tree_Phase_1
+                    (In_Tree                => List.Tree,
+                     Project                => List.Project,
+                     Success                => Success,
+                     From_Project_Node      => Loaded_Project,
+                     From_Project_Node_Tree => From_Project_Node_Tree,
+                     Env                    => Child_Env,
+                     Reset_Tree             => False);
+               else
+                  --  use the same environment as the rest of the aggregated
+                  --  projects, ie the one that was setup by the root aggregate
+                  Process_Project_Tree_Phase_1
+                    (In_Tree                => List.Tree,
+                     Project                => List.Project,
+                     Success                => Success,
+                     From_Project_Node      => Loaded_Project,
+                     From_Project_Node_Tree => From_Project_Node_Tree,
+                     Env                    => Env,
+                     Reset_Tree             => False);
+               end if;
             else
                Debug_Output ("Failed to parse", Name_Id (List.Path));
             end if;
@@ -2650,21 +2642,20 @@ package body Prj.Proc is
       begin
          Extended_Pkg := Project.Extends.Decl.Packages;
          while Extended_Pkg /= No_Package loop
-            Element := In_Tree.Packages.Table (Extended_Pkg);
+            Element := Shared.Packages.Table (Extended_Pkg);
 
             Current_Pkg := First;
             while Current_Pkg /= No_Package
-              and then In_Tree.Packages.Table (Current_Pkg).Name /=
+              and then Shared.Packages.Table (Current_Pkg).Name /=
               Element.Name
             loop
-               Current_Pkg :=
-                 In_Tree.Packages.Table (Current_Pkg).Next;
+               Current_Pkg := Shared.Packages.Table (Current_Pkg).Next;
             end loop;
 
             if Current_Pkg = No_Package then
-               Package_Table.Increment_Last (In_Tree.Packages);
-               Current_Pkg := Package_Table.Last (In_Tree.Packages);
-               In_Tree.Packages.Table (Current_Pkg) :=
+               Package_Table.Increment_Last (Shared.Packages);
+               Current_Pkg := Package_Table.Last (Shared.Packages);
+               Shared.Packages.Table (Current_Pkg) :=
                  (Name   => Element.Name,
                   Decl   => No_Declarations,
                   Parent => No_Package,
@@ -2672,10 +2663,10 @@ package body Prj.Proc is
                Project.Decl.Packages := Current_Pkg;
                Copy_Package_Declarations
                  (From       => Element.Decl,
-                  To         => In_Tree.Packages.Table (Current_Pkg).Decl,
+                  To         => Shared.Packages.Table (Current_Pkg).Decl,
                   New_Loc    => No_Location,
                   Restricted => True,
-                  In_Tree    => In_Tree);
+                  Shared     => Shared);
             end if;
 
             Extended_Pkg := Element.Next;
@@ -2685,7 +2676,7 @@ package body Prj.Proc is
 
          Attribute1 := Project.Decl.Attributes;
          while Attribute1 /= No_Variable loop
-            Attr_Value1 := In_Tree.Variable_Elements. Table (Attribute1);
+            Attr_Value1 := Shared.Variable_Elements. Table (Attribute1);
             exit when Attr_Value1.Name = Snames.Name_Languages;
             Attribute1 := Attr_Value1.Next;
          end loop;
@@ -2698,7 +2689,7 @@ package body Prj.Proc is
 
             Attribute2 := Project.Extends.Decl.Attributes;
             while Attribute2 /= No_Variable loop
-               Attr_Value2 := In_Tree.Variable_Elements.Table (Attribute2);
+               Attr_Value2 := Shared.Variable_Elements.Table (Attribute2);
                exit when Attr_Value2.Name = Snames.Name_Languages;
                Attribute2 := Attr_Value2.Next;
             end loop;
@@ -2711,17 +2702,16 @@ package body Prj.Proc is
 
                if Attribute1 = No_Variable then
                   Variable_Element_Table.Increment_Last
-                    (In_Tree.Variable_Elements);
+                    (Shared.Variable_Elements);
                   Attribute1 := Variable_Element_Table.Last
-                    (In_Tree.Variable_Elements);
+                    (Shared.Variable_Elements);
                   Attr_Value1.Next := Project.Decl.Attributes;
                   Project.Decl.Attributes := Attribute1;
                end if;
 
                Attr_Value1.Name := Snames.Name_Languages;
                Attr_Value1.Value := Attr_Value2.Value;
-               In_Tree.Variable_Elements.Table
-                 (Attribute1) := Attr_Value1;
+               Shared.Variable_Elements.Table (Attribute1) := Attr_Value1;
             end if;
          end if;
       end Process_Extended_Project;
@@ -2806,13 +2796,24 @@ package body Prj.Proc is
               (Project,
                Name,
                Name_Id (Project.Directory.Name),
-               In_Tree,
+               In_Tree.Shared,
                Project.Decl,
                Prj.Attr.Attribute_First,
                Project_Level => True);
 
             Process_Imported_Projects (Imported, Limited_With => False);
 
+            if Project.Qualifier = Aggregate
+              and then In_Tree.Is_Root_Tree
+            then
+               Initialize_And_Copy (Child_Env, Copy_From => Env);
+            else
+               --  No need to initialize Child_Env, since it will not be
+               --  used anyway by Process_Declarative_Items (only the root
+               --  aggregate can modify it, and it is never read anyway).
+               null;
+            end if;
+
             Declaration_Node :=
               Project_Declaration_Of
                 (From_Project_Node, From_Project_Node_Tree);
@@ -2824,9 +2825,7 @@ package body Prj.Proc is
                  (Declaration_Node, From_Project_Node_Tree),
                From_Project_Node_Tree => From_Project_Node_Tree,
                Env                    => Env,
-               Extended_By            => Project,
-               Child_Env              => Child_Env,
-               Is_Root_Project        => False);
+               Extended_By            => Project);
 
             Process_Declarative_Items
               (Project                => Project,
@@ -2837,8 +2836,7 @@ package body Prj.Proc is
                Pkg                    => No_Package,
                Item                   => First_Declarative_Item_Of
                  (Declaration_Node, From_Project_Node_Tree),
-               Child_Env              => Child_Env,
-               Can_Modify_Child_Env   => Is_Root_Project);
+               Child_Env              => Child_Env);
 
             if Project.Extends /= No_Project then
                Process_Extended_Project;
@@ -2849,6 +2847,12 @@ package body Prj.Proc is
             if Err_Vars.Total_Errors_Detected = 0 then
                Process_Aggregated_Projects;
             end if;
+
+            if Project.Qualifier = Aggregate
+              and then In_Tree.Is_Root_Tree
+            then
+               Free (Child_Env);
+            end if;
          end;
       end if;
    end Recursive_Process;