--- a/gcc/ada/libgnat/s-parame.ads	Fri Oct 27 22:46:09 2017 +0900
+++ b/gcc/ada/libgnat/s-parame.ads	Thu Oct 25 07:37:49 2018 +0900
@@ -6,7 +6,7 @@
 --                                                                          --
 --                                 S p e c                                  --
 --                                                                          --
---          Copyright (C) 1992-2017, Free Software Foundation, Inc.         --
+--          Copyright (C) 1992-2018, 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- --
@@ -55,11 +55,14 @@
    -- Task And Stack Allocation Control --
    ---------------------------------------
 
-   type Task_Storage_Size is new Integer;
-   --  Type used in tasking units for task storage size
-
-   type Size_Type is new Task_Storage_Size;
-   --  Type used to provide task storage size to runtime
+   type Size_Type is range
+     -(2 ** (Integer'(Standard'Address_Size) - 1)) ..
+     +(2 ** (Integer'(Standard'Address_Size) - 1)) - 1;
+   --  Type used to provide task stack sizes to the runtime. Sized to permit
+   --  stack sizes of up to half the total addressable memory space. This may
+   --  seem excessively large (even for 32-bit systems), however there are many
+   --  instances of users requiring large stack sizes (for example string
+   --  processing).
 
    Unspecified_Size : constant Size_Type := Size_Type'First;
    --  Value used to indicate that no size type is set
@@ -93,10 +96,6 @@
    --  The run-time chosen default size for secondary stacks that may be
    --  overriden by the user with the use of binder -D switch.
 
-   function Default_Sec_Stack_Size return Size_Type;
-   --  The default initial size for secondary stacks that reflects any user
-   --  specified default via the binder -D switch.
-
    Sec_Stack_Dynamic : constant Boolean := True;
    --  Indicates if secondary stacks can grow and shrink at run-time. If False,
    --  the size of a secondary stack is fixed at the point of its creation.