[multiple changes]

2015-05-22  Robert Dewar  <dewar@adacore.com>

	* einfo.ads: Minor comment updates.
	* exp_unst.adb: Move Subps table to spec Don't remove old entries
	from table Add Last field to record last entry used.
	* exp_unst.ads: Move Subps table here from body So that Cprint
	can access saved values.

2015-05-22  Bob Duff  <duff@adacore.com>

	* a-cdlili.adb, a-cdlili.ads, a-cohama.adb, a-cohama.ads,
	* a-cohase.adb, a-cohase.ads, a-convec.adb, a-convec.ads,
	* a-coorma.adb, a-coorma.ads, a-coorse.adb, a-coorse.ads:
	(Pseudo_Reference, Element_Access, Get_Element_Access): New
	declarations added for use by performance improvements in exp_ch5.adb.
	* snames.ads-tmpl: New names referenced by exp_ch5.adb.
	* exp_ch5.adb: Speed up "for ... of" loops for predefined containers.
	Instead of doing literally what the RM calls for, we do something
	equivalent that avoids expensive operations inside the loop. If the
	container package has appropriate Next, Pseudo_Reference,
	Element_Access, Get_Element_Access declarations, we invoke the
	optimization.
	* snames.ads-tmpl: Note speed improvement.

From-SVN: r223563

gcc/ada/ChangeLog

+2015-05-22  Robert Dewar  <dewar@adacore.com>
+
+	* einfo.ads: Minor comment updates.
+	* exp_unst.adb: Move Subps table to spec Don't remove old entries
+	from table Add Last field to record last entry used.
+	* exp_unst.ads: Move Subps table here from body So that Cprint
+	can access saved values.
+
+2015-05-22  Bob Duff  <duff@adacore.com>
+
+	* a-cdlili.adb, a-cdlili.ads, a-cohama.adb, a-cohama.ads,
+	* a-cohase.adb, a-cohase.ads, a-convec.adb, a-convec.ads,
+	* a-coorma.adb, a-coorma.ads, a-coorse.adb, a-coorse.ads:
+	(Pseudo_Reference, Element_Access, Get_Element_Access): New
+	declarations added for use by performance improvements in exp_ch5.adb.
+	* snames.ads-tmpl: New names referenced by exp_ch5.adb.
+	* exp_ch5.adb: Speed up "for ... of" loops for predefined containers.
+	Instead of doing literally what the RM calls for, we do something
+	equivalent that avoids expensive operations inside the loop. If the
+	container package has appropriate Next, Pseudo_Reference,
+	Element_Access, Get_Element_Access declarations, we invoke the
+	optimization.
+	* snames.ads-tmpl: Note speed improvement.
+
 2015-05-22  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* einfo.ads (Is_Atomic_Or_VFA): Move to XEINFO INLINES section.

gcc/ada/a-cdlili.adb

@@ -6,7 +6,7 @@
 --                                                                          --
 --                                 B o d y                                  --
 --                                                                          --
---          Copyright (C) 2004-2014, Free Software Foundation, Inc.         --
+--          Copyright (C) 2004-2015, 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- --
@@ -923,6 +923,16 @@ package body Ada.Containers.Doubly_Linked_Lists is
 
    end Generic_Sorting;
 
+   ------------------------
+   -- Get_Element_Access --
+   ------------------------
+
+   function Get_Element_Access
+     (Position : Cursor) return not null Element_Access is
+   begin
+      return Position.Node.Element'Access;
+   end Get_Element_Access;
+
    -----------------
    -- Has_Element --
    -----------------
@@ -1384,6 +1394,25 @@ package body Ada.Containers.Doubly_Linked_Lists is
       end if;
    end Previous;
 
+   ----------------------
+   -- Pseudo_Reference --
+   ----------------------
+
+   function Pseudo_Reference
+     (Container : aliased List'Class) return Reference_Control_Type
+   is
+      C : constant List_Access := Container'Unrestricted_Access;
+      B : Natural renames C.Busy;
+      L : Natural renames C.Lock;
+   begin
+      return R : constant Reference_Control_Type :=
+        (Controlled with C)
+      do
+         B := B + 1;
+         L := L + 1;
+      end return;
+   end Pseudo_Reference;
+
    -------------------
    -- Query_Element --
    -------------------

gcc/ada/a-cdlili.ads

@@ -362,6 +362,24 @@ private
 
    for Reference_Type'Read use Read;
 
+   --  Three operations are used to optimize in the expansion of "for ... of"
+   --  loops: the Next(Cursor) procedure in the visible part, and the following
+   --  Pseudo_Reference and Get_Element_Access functions. See Sem_Ch5 for
+   --  details.
+
+   function Pseudo_Reference
+     (Container : aliased List'Class) return Reference_Control_Type;
+   pragma Inline (Pseudo_Reference);
+   --  Creates an object of type Reference_Control_Type pointing to the
+   --  container, and increments the Lock. Finalization of this object will
+   --  decrement the Lock.
+
+   type Element_Access is access all Element_Type;
+
+   function Get_Element_Access
+     (Position : Cursor) return not null Element_Access;
+   --  Returns a pointer to the element designated by Position.
+
    Empty_List : constant List := (Controlled with null, null, 0, 0, 0);
 
    No_Element : constant Cursor := Cursor'(null, null);

gcc/ada/a-cohama.adb

@@ -6,7 +6,7 @@
 --                                                                          --
 --                                 B o d y                                  --
 --                                                                          --
---          Copyright (C) 2004-2014, Free Software Foundation, Inc.         --
+--          Copyright (C) 2004-2015, 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- --
@@ -555,6 +555,16 @@ package body Ada.Containers.Hashed_Maps is
       end if;
    end Free;
 
+   ------------------------
+   -- Get_Element_Access --
+   ------------------------
+
+   function Get_Element_Access
+     (Position : Cursor) return not null Element_Access is
+   begin
+      return Position.Node.Element'Access;
+   end Get_Element_Access;
+
    -----------------
    -- Has_Element --
    -----------------
@@ -858,6 +868,25 @@ package body Ada.Containers.Hashed_Maps is
       return Next (Position);
    end Next;
 
+   ----------------------
+   -- Pseudo_Reference --
+   ----------------------
+
+   function Pseudo_Reference
+     (Container : aliased Map'Class) return Reference_Control_Type
+   is
+      C : constant Map_Access := Container'Unrestricted_Access;
+      B : Natural renames C.HT.Busy;
+      L : Natural renames C.HT.Lock;
+   begin
+      return R : constant Reference_Control_Type :=
+        (Controlled with C)
+      do
+         B := B + 1;
+         L := L + 1;
+      end return;
+   end Pseudo_Reference;
+
    -------------------
    -- Query_Element --
    -------------------

gcc/ada/a-cohama.ads

@@ -300,7 +300,7 @@ package Ada.Containers.Hashed_Maps is
    --  Calls Process for each node in the map
 
    function Iterate
-     (Container : Map) return Map_Iterator_Interfaces.Forward_Iterator'class;
+     (Container : Map) return Map_Iterator_Interfaces.Forward_Iterator'Class;
 
 private
    pragma Inline ("=");
@@ -428,6 +428,24 @@ private
 
    for Reference_Type'Read use Read;
 
+   --  Three operations are used to optimize in the expansion of "for ... of"
+   --  loops: the Next(Cursor) procedure in the visible part, and the following
+   --  Pseudo_Reference and Get_Element_Access functions. See Sem_Ch5 for
+   --  details.
+
+   function Pseudo_Reference
+     (Container : aliased Map'Class) return Reference_Control_Type;
+   pragma Inline (Pseudo_Reference);
+   --  Creates an object of type Reference_Control_Type pointing to the
+   --  container, and increments the Lock. Finalization of this object will
+   --  decrement the Lock.
+
+   type Element_Access is access all Element_Type;
+
+   function Get_Element_Access
+     (Position : Cursor) return not null Element_Access;
+   --  Returns a pointer to the element designated by Position.
+
    Empty_Map : constant Map := (Controlled with HT => (null, 0, 0, 0));
 
    No_Element : constant Cursor := (Container => null, Node => null);

gcc/ada/a-cohase.adb

@@ -6,7 +6,7 @@
 --                                                                          --
 --                                 B o d y                                  --
 --                                                                          --
---          Copyright (C) 2004-2014, Free Software Foundation, Inc.         --
+--          Copyright (C) 2004-2015, 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- --
@@ -722,6 +722,16 @@ package body Ada.Containers.Hashed_Sets is
       end if;
    end Free;
 
+   ------------------------
+   -- Get_Element_Access --
+   ------------------------
+
+   function Get_Element_Access
+     (Position : Cursor) return not null Element_Access is
+   begin
+      return Position.Node.Element'Access;
+   end Get_Element_Access;
+
    -----------------
    -- Has_Element --
    -----------------
@@ -1154,6 +1164,25 @@ package body Ada.Containers.Hashed_Sets is
       return False;
    end Overlap;
 
+   ----------------------
+   -- Pseudo_Reference --
+   ----------------------
+
+   function Pseudo_Reference
+     (Container : aliased Set'Class) return Reference_Control_Type
+   is
+      C : constant Set_Access := Container'Unrestricted_Access;
+      B : Natural renames C.HT.Busy;
+      L : Natural renames C.HT.Lock;
+   begin
+      return R : constant Reference_Control_Type :=
+        (Controlled with C)
+      do
+         B := B + 1;
+         L := L + 1;
+      end return;
+   end Pseudo_Reference;
+
    -------------------
    -- Query_Element --
    -------------------

gcc/ada/a-cohase.ads

@@ -573,6 +573,24 @@ private
 
    for Constant_Reference_Type'Write use Write;
 
+   --  Three operations are used to optimize in the expansion of "for ... of"
+   --  loops: the Next(Cursor) procedure in the visible part, and the following
+   --  Pseudo_Reference and Get_Element_Access functions. See Sem_Ch5 for
+   --  details.
+
+   function Pseudo_Reference
+     (Container : aliased Set'Class) return Reference_Control_Type;
+   pragma Inline (Pseudo_Reference);
+   --  Creates an object of type Reference_Control_Type pointing to the
+   --  container, and increments the Lock. Finalization of this object will
+   --  decrement the Lock.
+
+   type Element_Access is access all Element_Type;
+
+   function Get_Element_Access
+     (Position : Cursor) return not null Element_Access;
+   --  Returns a pointer to the element designated by Position.
+
    Empty_Set : constant Set := (Controlled with HT => (null, 0, 0, 0));
 
    No_Element : constant Cursor := (Container => null, Node => null);

gcc/ada/a-convec.adb

@@ -6,7 +6,7 @@
 --                                                                          --
 --                                 B o d y                                  --
 --                                                                          --
---          Copyright (C) 2004-2014, Free Software Foundation, Inc.         --
+--          Copyright (C) 2004-2015, 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- --
@@ -1269,6 +1269,16 @@ package body Ada.Containers.Vectors is
 
    end Generic_Sorting;
 
+   ------------------------
+   -- Get_Element_Access --
+   ------------------------
+
+   function Get_Element_Access
+     (Position : Cursor) return not null Element_Access is
+   begin
+      return Position.Container.Elements.EA (Position.Index)'Access;
+   end Get_Element_Access;
+
    -----------------
    -- Has_Element --
    -----------------
@@ -2673,6 +2683,25 @@ package body Ada.Containers.Vectors is
       end if;
    end Previous;
 
+   ----------------------
+   -- Pseudo_Reference --
+   ----------------------
+
+   function Pseudo_Reference
+     (Container : aliased Vector'Class) return Reference_Control_Type
+   is
+      C : constant Vector_Access := Container'Unrestricted_Access;
+      B : Natural renames C.Busy;
+      L : Natural renames C.Lock;
+   begin
+      return R : constant Reference_Control_Type :=
+        (Controlled with C)
+      do
+         B := B + 1;
+         L := L + 1;
+      end return;
+   end Pseudo_Reference;
+
    -------------------
    -- Query_Element --
    -------------------

gcc/ada/a-convec.ads

@@ -475,6 +475,24 @@ private
 
    for Reference_Type'Read use Read;
 
+   --  Three operations are used to optimize in the expansion of "for ... of"
+   --  loops: the Next(Cursor) procedure in the visible part, and the following
+   --  Pseudo_Reference and Get_Element_Access functions. See Sem_Ch5 for
+   --  details.
+
+   function Pseudo_Reference
+     (Container : aliased Vector'Class) return Reference_Control_Type;
+   pragma Inline (Pseudo_Reference);
+   --  Creates an object of type Reference_Control_Type pointing to the
+   --  container, and increments the Lock. Finalization of this object will
+   --  decrement the Lock.
+
+   type Element_Access is access all Element_Type;
+
+   function Get_Element_Access
+     (Position : Cursor) return not null Element_Access;
+   --  Returns a pointer to the element designated by Position.
+
    No_Element   : constant Cursor := Cursor'(null, Index_Type'First);
 
    Empty_Vector : constant Vector := (Controlled with null, No_Index, 0, 0);

gcc/ada/a-coorma.adb

@@ -6,7 +6,7 @@
 --                                                                          --
 --                                 B o d y                                  --
 --                                                                          --
---          Copyright (C) 2004-2014, Free Software Foundation, Inc.         --
+--          Copyright (C) 2004-2015, 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- --
@@ -677,6 +677,16 @@ package body Ada.Containers.Ordered_Maps is
       Deallocate (X);
    end Free;
 
+   ------------------------
+   -- Get_Element_Access --
+   ------------------------
+
+   function Get_Element_Access
+     (Position : Cursor) return not null Element_Access is
+   begin
+      return Position.Node.Element'Access;
+   end Get_Element_Access;
+
    -----------------
    -- Has_Element --
    -----------------
@@ -1198,6 +1208,25 @@ package body Ada.Containers.Ordered_Maps is
       return Previous (Position);
    end Previous;
 
+   ----------------------
+   -- Pseudo_Reference --
+   ----------------------
+
+   function Pseudo_Reference
+     (Container : aliased Map'Class) return Reference_Control_Type
+   is
+      C : constant Map_Access := Container'Unrestricted_Access;
+      B : Natural renames C.Tree.Busy;
+      L : Natural renames C.Tree.Lock;
+   begin
+      return R : constant Reference_Control_Type :=
+        (Controlled with C)
+      do
+         B := B + 1;
+         L := L + 1;
+      end return;
+   end Pseudo_Reference;
+
    -------------------
    -- Query_Element --
    -------------------

gcc/ada/a-coorma.ads

@@ -352,6 +352,24 @@ private
 
    for Reference_Type'Write use Write;
 
+   --  Three operations are used to optimize in the expansion of "for ... of"
+   --  loops: the Next(Cursor) procedure in the visible part, and the following
+   --  Pseudo_Reference and Get_Element_Access functions.  See Sem_Ch5 for
+   --  details.
+
+   function Pseudo_Reference
+     (Container : aliased Map'Class) return Reference_Control_Type;
+   pragma Inline (Pseudo_Reference);
+   --  Creates an object of type Reference_Control_Type pointing to the
+   --  container, and increments the Lock. Finalization of this object will
+   --  decrement the Lock.
+
+   type Element_Access is access all Element_Type;
+
+   function Get_Element_Access
+     (Position : Cursor) return not null Element_Access;
+   --  Returns a pointer to the element designated by Position.
+
    Empty_Map : constant Map :=
                  (Controlled with Tree => (First  => null,
                                            Last   => null,

gcc/ada/a-coorse.adb

@@ -6,7 +6,7 @@
 --                                                                          --
 --                                 B o d y                                  --
 --                                                                          --
---          Copyright (C) 2004-2014, Free Software Foundation, Inc.         --
+--          Copyright (C) 2004-2015, 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- --
@@ -1087,6 +1087,16 @@ package body Ada.Containers.Ordered_Sets is
 
    end Generic_Keys;
 
+   ------------------------
+   -- Get_Element_Access --
+   ------------------------
+
+   function Get_Element_Access
+     (Position : Cursor) return not null Element_Access is
+   begin
+      return Position.Node.Element'Access;
+   end Get_Element_Access;
+
    -----------------
    -- Has_Element --
    -----------------
@@ -1616,6 +1626,25 @@ package body Ada.Containers.Ordered_Sets is
       return Previous (Position);
    end Previous;
 
+   ----------------------
+   -- Pseudo_Reference --
+   ----------------------
+
+   function Pseudo_Reference
+     (Container : aliased Set'Class) return Reference_Control_Type
+   is
+      C : constant Set_Access := Container'Unrestricted_Access;
+      B : Natural renames C.Tree.Busy;
+      L : Natural renames C.Tree.Lock;
+   begin
+      return R : constant Reference_Control_Type :=
+        (Controlled with C)
+      do
+         B := B + 1;
+         L := L + 1;
+      end return;
+   end Pseudo_Reference;
+
    -------------------
    -- Query_Element --
    -------------------

gcc/ada/a-coorse.ads

@@ -413,6 +413,24 @@ private
 
    for Constant_Reference_Type'Read use Read;
 
+   --  Three operations are used to optimize in the expansion of "for ... of"
+   --  loops: the Next(Cursor) procedure in the visible part, and the following
+   --  Pseudo_Reference and Get_Element_Access functions. See Sem_Ch5 for
+   --  details.
+
+   function Pseudo_Reference
+     (Container : aliased Set'Class) return Reference_Control_Type;
+   pragma Inline (Pseudo_Reference);
+   --  Creates an object of type Reference_Control_Type pointing to the
+   --  container, and increments the Lock. Finalization of this object will
+   --  decrement the Lock.
+
+   type Element_Access is access all Element_Type;
+
+   function Get_Element_Access
+     (Position : Cursor) return not null Element_Access;
+   --  Returns a pointer to the element designated by Position.
+
    Empty_Set : constant Set :=
                  (Controlled with Tree => (First  => null,
                                            Last   => null,

gcc/ada/einfo.ads

@@ -4201,8 +4201,11 @@ package Einfo is
 --       names to access entries in this list.
 
 --    Subps_Index (Uint24)
---       Used during Exp_Inst.Unnest_Subprogram to hold the index in the Subps
---       table for a subprogram. See processing in this procedure for details.
+--       Present in subprogram entries. Set if the subprogram contains nested
+--       subprograms, or is a subprogram nested within such a subprogram. Holds
+--       the index in the Exp_Unst.Subps table for the subprogram. Note that
+--       for the outer level subprogram, this is the starting index in the Subp
+--       table for the entries for this subprogram.
 
 --    Suppress_Elaboration_Warnings (Flag148)
 --       Defined in all entities, can be set only for subprogram entities and

gcc/ada/exp_unst.ads

@@ -25,6 +25,7 @@
 
 --  Expand routines for unnesting subprograms
 
+with Table;
 with Types; use Types;
 
 package Exp_Unst is
@@ -175,9 +176,9 @@ package Exp_Unst is
    --         rv : Address;
    --      end record;
 
-   --      AREC1 : aliased AREC1T;
-
    --      type AREC1PT is access all AREC1T;
+
+   --      AREC1  : aliased AREC1T;
    --      AREC1P : constant AREC1PT := AREC1'Access;
 
    --   The fields of AREC1 are set at the point the corresponding entity
@@ -213,8 +214,9 @@ package Exp_Unst is
    --             rv : Address;
    --          end record;
    --
-   --          AREC1 : aliased AREC1T;
    --          type AREC1PT is access all AREC1T;
+   --
+   --          AREC1 : aliased AREC1T;
    --          AREC1P : constant AREC1PT := AREC1'Access;
    --
    --          AREC1.b := b'Address;
@@ -362,8 +364,9 @@ package Exp_Unst is
    --             dynam_LAST : Address;
    --          end record;
    --
-   --          AREC1 : aliased AREC1T;
    --          type AREC1PT is access all AREC1T;
+   --
+   --          AREC1 : aliased AREC1T;
    --          AREC1P : constant AREC1PT := AREC1'Access;
    --
    --          AREC1.x := x'Address;
@@ -422,8 +425,9 @@ package Exp_Unst is
    --           v1 : Address;
    --        end record;
    --
-   --        AREC1 : aliased AREC1T;
    --        type AREC1PT is access all AREC1T;
+   --
+   --        AREC1 : aliased AREC1T;
    --        AREC1P : constant AREC1PT := AREC1'Access;
    --
    --        v1 : integer := x;
@@ -431,14 +435,17 @@ package Exp_Unst is
    --
    --        function inner1 (y : integer; AREC1F : AREC1PT) return integer is
    --           type AREC2T is record
-   --              AREC1U : AREC1PT := AREC1F;
+   --              AREC1U : AREC1PT;
    --              v2     : Address;
    --           end record;
    --
-   --           AREC2 : aliased AREC2T;
    --           type AREC2PT is access all AREC2T;
+   --
+   --           AREC2 : aliased AREC2T;
    --           AREC2P : constant AREC2PT := AREC2'Access;
    --
+   --           AREC2.AREC1U := AREC1F;
+   --
    --           v2 : integer := Integer'Deref (AREC1F.v1) {+} 1;
    --           AREC2.v2 := v2'Address;
    --
@@ -525,6 +532,148 @@ package Exp_Unst is
    --  with the issue of clashing names (mnames__inner, mnames__inner__inner),
    --  and with overloading (mnames__f, mnames__f__2).
 
+   --  In addition, the declarations of ARECnT and ARECnPT get moved to the
+   --  outer level when we actually generate C code, so we suffix these names
+   --  with the corresponding entity name to make sure they are unique.
+
+   ---------------------------
+   -- Terminology for Calls --
+   ---------------------------
+
+   --  The level of a subprogram in the nest being analyzed is defined to be
+   --  the level of nesting, so the outer level subprogram (the one passed to
+   --  Unnest_Subprogram) is 1, subprograms immediately nested within this
+   --  outer level subprogram have a level of 2, etc.
+
+   --  Calls within the nest being analyzed are of three types:
+
+   --    Downward call: this is a call from a subprogram to a subprogram that
+   --    is immediately nested with in the caller, and thus has a level that
+   --    is one greater than the caller. It is a fundamental property of the
+   --    nesting structure and visibility that it is not possible to make a
+   --    call from level N to level M, where M is greater than N + 1.
+
+   --    Parallel call: this is a call from a nested subprogram to another
+   --    nested subprogram that is at the same level.
+
+   --    Upward call: this is a call from a subprogram to a subprogram that
+   --    encloses the caller. The level of the callee is less than the level
+   --    of the caller, and there is no limit on the difference, e.g. for an
+   --    uplevel call, a subprogram at level 5 can call one at level 2 or even
+   --    the outer level subprogram at level 1.
+
+   -----------
+   -- Subps --
+   -----------
+
+   --  Table to record subprograms within the nest being currently analyzed.
+   --  Entries in this table are made for each subprogram expanded, and do not
+   --  get cleared as we complete the expansion, since we want the table info
+   --  around in Cprint for the actual unnesting operation. Subps_First in this
+   --  unit records the starting entry in the table for the entries for Subp
+   --  and this is also recorded in the Subps_Index field of the outer level
+   --  subprogram in the nest. The last subps index for the nest can be found
+   --  in the Subp_Entry Last field of this first entry.
+
+   subtype SI_Type is Nat;
+   --  Index type for the table
+
+   Subps_First : SI_Type;
+   --  Record starting index for entries in the current nest (this is the table
+   --  index of the entry for Subp itself, and is recorded in the Subps_Index
+   --  field of the entity for this subprogram).
+
+   type Subp_Entry is record
+      Ent : Entity_Id;
+      --  Entity of the subprogram
+
+      Bod : Node_Id;
+      --  Subprogram_Body node for this subprogram
+
+      Lev : Nat;
+      --  Subprogram level (1 = outer subprogram (Subp argument), 2 = nested
+      --  immediately within this outer subprogram etc.)
+
+      Reachable : Boolean;
+      --  This flag is set True if there is a call path from the outer level
+      --  subprogram to this subprogram. If Reachable is False, it means that
+      --  the subprogram is declared but not actually referenced. We remove
+      --  such subprograms from the tree, which simplifies our task, because
+      --  we don't have to worry about e.g. uplevel references from such an
+      --  unreferenced subpogram, which might require (useless) activation
+      --  records to be created. This is computed by setting the outer level
+      --  subprogram (Subp itself) as reachable, and then doing a transitive
+      --  closure following all calls.
+
+      Uplevel_Ref : Nat;
+      --  The outermost level which defines entities which this subprogram
+      --  references either directly or indirectly via a call. This cannot
+      --  be greater than Lev. If it is equal to Lev, then it means that the
+      --  subprogram does not make any uplevel references and that thus it
+      --  does not need an activation record pointer passed. If it is less than
+      --  Lev, then an activation record pointer is needed, since there is at
+      --  least one uplevel reference. This is computed by initially setting
+      --  Uplevel_Ref to Lev for all subprograms. Then on the initial tree
+      --  traversal, decreasing Uplevel_Ref for an explicit uplevel reference,
+      --  and finally by doing a transitive closure that follows calls (if A
+      --  calls B and B has an uplevel reference to level X, then A references
+      --  level X indirectly).
+
+      Declares_AREC : Boolean;
+      --  This is set True for a subprogram which include the declarations
+      --  for a local activation record to be passed on downward calls. It
+      --  is set True for the target level of an uplevel reference, and for
+      --  all intervening nested subprograms. For example, if a subprogram X
+      --  at level 5 makes an uplevel reference to an entity declared in a
+      --  level 2 subprogram, then the subprograms at levels 4,3,2 enclosing
+      --  the level 5 subprogram will have this flag set True.
+
+      Uents : Elist_Id;
+      --  This is a list of entities declared in this subprogram which are
+      --  uplevel referenced. It contains both objects (which will be put in
+      --  the corresponding AREC activation record), and types. The types are
+      --  not put in the AREC activation record, but referenced bounds (i.e.
+      --  generated _FIRST and _LAST entites, and formal parameters) will be
+      --  in the list in their own right.
+
+      Last : SI_Type;
+      --  This field is set only in the entry for the outer level subprogram
+      --  in a nest, and records the last index in the Subp table for all the
+      --  entries for subprograms in this nest.
+
+      ARECnF : Entity_Id;
+      --  This entity is defined for all subprograms which need an extra formal
+      --  that contains a pointer to the activation record needed for uplevel
+      --  references. ARECnF must be defined for any subprogram which has a
+      --  direct or indirect uplevel reference (i.e. Reference_Level < Lev).
+
+      ARECn   : Entity_Id;
+      ARECnT  : Entity_Id;
+      ARECnPT : Entity_Id;
+      ARECnP  : Entity_Id;
+      --  These AREC entities are defined only for subprograms for which we
+      --  generate an activation record declaration, i.e. for subprograms for
+      --  which the Declares_AREC flag is set True.
+
+      ARECnU : Entity_Id;
+      --  This AREC entity is the uplink component. It is other than Empty only
+      --  for nested subprograms that declare an activation record as indicated
+      --  by Declares_AREC being Ture, and which have uplevel references (Lev
+      --  greater than Uplevel_Ref). It is the additional component in the
+      --  activation record that references the ARECnF pointer (which points
+      --  the activation record one level higher, thus forming the chain).
+
+   end record;
+
+   package Subps is new Table.Table (
+     Table_Component_Type => Subp_Entry,
+     Table_Index_Type     => SI_Type,
+     Table_Low_Bound      => 1,
+     Table_Initial        => 1000,
+     Table_Increment      => 200,
+     Table_Name           => "Unnest_Subps");
+   --  Records the subprograms in the nest whose outer subprogram is Subp
+
    -----------------
    -- Subprograms --
    -----------------

gcc/ada/snames.ads-tmpl

@@ -120,7 +120,7 @@ package Snames is
    Name_uY : constant Name_Id := First_Name_Id + Character'Pos ('Y');
    Name_uZ : constant Name_Id := First_Name_Id + Character'Pos ('Z');
 
-   --  Note: the following table is read by the utility program XSNAMES, and
+   --  Note: the following table is read by the utility program 'xsnamest', and
    --  its format should not be changed without coordinating with this program.
 
    N : constant Name_Id := First_Name_Id + 256;
@@ -1411,6 +1411,9 @@ package Snames is
    Name_Forward_Iterator                 : constant Name_Id := N + $;
    Name_Reversible_Iterator              : constant Name_Id := N + $;
    Name_Previous                         : constant Name_Id := N + $;
+   Name_Pseudo_Reference                 : constant Name_Id := N + $;
+   Name_Reference_Control_Type           : constant Name_Id := N + $;
+   Name_Get_Element_Access               : constant Name_Id := N + $;
 
    --  Ada 2005 reserved words