[Ada] RTEMS: use default stack checking emulation package

[Ada] RTEMS: use default stack checking emulation package

[Pierre-Marie de Rodat]

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Remove the RTEMS specific version of System.Stack_Checking.Operations as
the internal RTEMS API it uses can only detect stack overflow after the
event, whereas the stack checking emulation is meant to detect the stack
overflow before it occurs. Use the standard
System.Stack_Checking.Operations package instead and include it's object
file in the runtime library.

Tested on x86_64-pc-linux-gnu, committed on trunk

gcc/ada/

	* Makefile.rtl (RTEMS): Add s-stchop.o to
	EXTRA_GNATRTL_NONTASKING_OBJS, remove s-stchop__rtems.adb.
	* libgnat/s-stchop__rtems.adb: Removed.

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diff --git a/gcc/ada/Makefile.rtl b/gcc/ada/Makefile.rtl
--- a/gcc/ada/Makefile.rtl
+++ b/gcc/ada/Makefile.rtl
@@ -2057,9 +2057,10 @@ ifeq ($(strip $(filter-out rtems%,$(target_os))),)
   s-taprop.adb<libgnarl/s-taprop__posix.adb \
   s-taspri.ads<libgnarl/s-taspri__posix.ads \
   s-tpopsp.adb<libgnarl/s-tpopsp__tls.adb \
-  s-stchop.adb<libgnat/s-stchop__rtems.adb \
   s-interr.adb<libgnarl/s-interr__hwint.adb
 
+  EXTRA_GNATRTL_NONTASKING_OBJS += s-stchop.o
+
   ifeq ($(strip $(filter-out arm%, $(target_cpu))),)
     EH_MECHANISM=-arm
   else


diff --git a/gcc/ada/libgnat/s-stchop__rtems.adb /dev/null
deleted file mode 100644
--- a/gcc/ada/libgnat/s-stchop__rtems.adb
+++ /dev/null
@@ -1,113 +0,0 @@
-------------------------------------------------------------------------------
---                                                                          --
---                 GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS                 --
---                                                                          --
---     S Y S T E M . S T A C K _ C H E C K I N G . O P E R A T I O N S      --
---                                                                          --
---                                  B o d y                                 --
---                                                                          --
---          Copyright (C) 1999-2021, Free Software Foundation, Inc.         --
---                                                                          --
--- GNARL 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- --
--- ware  Foundation;  either version 3,  or (at your option) any later ver- --
--- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
--- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
--- or FITNESS FOR A PARTICULAR PURPOSE.                                     --
---                                                                          --
--- As a special exception under Section 7 of GPL version 3, you are granted --
--- additional permissions described in the GCC Runtime Library Exception,   --
--- version 3.1, as published by the Free Software Foundation.               --
---                                                                          --
--- You should have received a copy of the GNU General Public License and    --
--- a copy of the GCC Runtime Library Exception along with this program;     --
--- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
--- <http://www.gnu.org/licenses/>.                                          --
---                                                                          --
--- GNARL was developed by the GNARL team at Florida State University.       --
--- Extensive contributions were provided by Ada Core Technologies, Inc.     --
---                                                                          --
-------------------------------------------------------------------------------
-
---  This is the RTEMS version of this package.
---  This file should be kept synchronized with the general implementation
---  provided by s-stchop.adb.
-
-pragma Restrictions (No_Elaboration_Code);
---  We want to guarantee the absence of elaboration code because the
---  binder does not handle references to this package.
-
-with Ada.Exceptions;
-
-with Interfaces.C; use Interfaces.C;
-
-package body System.Stack_Checking.Operations is
-
-   ----------------------------
-   -- Invalidate_Stack_Cache --
-   ----------------------------
-
-   procedure Invalidate_Stack_Cache (Any_Stack : Stack_Access) is
-      pragma Warnings (Off, Any_Stack);
-   begin
-      Cache := Null_Stack;
-   end Invalidate_Stack_Cache;
-
-   -----------------------------
-   -- Notify_Stack_Attributes --
-   -----------------------------
-
-   procedure Notify_Stack_Attributes
-     (Initial_SP : System.Address;
-      Size       : System.Storage_Elements.Storage_Offset)
-   is
-
-      --  RTEMS keeps all the information we need.
-
-      pragma Unreferenced (Size);
-      pragma Unreferenced (Initial_SP);
-
-   begin
-      null;
-   end Notify_Stack_Attributes;
-
-   -----------------
-   -- Stack_Check --
-   -----------------
-
-   function Stack_Check
-     (Stack_Address : System.Address) return Stack_Access
-   is
-      pragma Unreferenced (Stack_Address);
-
-      --  RTEMS has a routine to check if the stack is blown.
-      --  It returns a C99 bool.
-      function rtems_stack_checker_is_blown return Interfaces.C.unsigned_char;
-      pragma Import (C,
-         rtems_stack_checker_is_blown, "rtems_stack_checker_is_blown");
-
-   begin
-      --  RTEMS has a routine to check this.  So use it.
-
-      if rtems_stack_checker_is_blown /= 0 then
-         Ada.Exceptions.Raise_Exception
-           (E       => Storage_Error'Identity,
-            Message => "stack overflow detected");
-      end if;
-
-      return null;
-
-   end Stack_Check;
-
-   ------------------------
-   -- Update_Stack_Cache --
-   ------------------------
-
-   procedure Update_Stack_Cache (Stack : Stack_Access) is
-   begin
-      if not Multi_Processor then
-         Cache := Stack;
-      end if;
-   end Update_Stack_Cache;
-
-end System.Stack_Checking.Operations;