------------------------------------------------------------------------------
--                                                                          --
--                         GNAT RUN-TIME COMPONENTS                         --
--                                                                          --
--              S Y S T E M . T R A C E B A C K _ E N T R I E S             --
--                                                                          --
--                                 S p e c                                  --
--                                                                          --
--          Copyright (C) 2003-2019, Free Software Foundation, Inc.         --
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-- This specification is derived from the Ada Reference Manual for use with --
-- GNAT. The copyright notice above, and the license provisions that follow --
-- apply solely to the  contents of the part following the private keyword. --
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-- 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- --
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-- <http://www.gnu.org/licenses/>.                                          --
--                                                                          --
-- GNAT was originally developed  by the GNAT team at  New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc.      --
--                                                                          --
------------------------------------------------------------------------------

--  This package offers an abstraction of what is stored in traceback arrays
--  for call-chain computation purposes. By default, as defined in this
--  version of the package, an entry is a mere code location representing the
--  address of a call instruction part of the call-chain.

pragma Polling (Off);
--  We must turn polling off for this unit, because otherwise we get
--  elaboration circularities with Ada.Exceptions.

pragma Compiler_Unit_Warning;

package System.Traceback_Entries is
   pragma Preelaborate;

   subtype Traceback_Entry is System.Address;
   --  This subtype defines what each traceback array entry contains

   Null_TB_Entry : constant Traceback_Entry := System.Null_Address;
   --  This is the value to be used when initializing an entry

   type Tracebacks_Array is array (Positive range <>) of Traceback_Entry;

   function PC_For (TB_Entry : Traceback_Entry) return System.Address;
   pragma Inline (PC_For);
   --  Returns the address of the call instruction associated with the
   --  provided entry.

   function TB_Entry_For (PC : System.Address) return Traceback_Entry;
   pragma Inline (TB_Entry_For);
   --  Returns an entry representing a frame for a call instruction at PC

end System.Traceback_Entries;
