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------------------------------------------------------------------------------

--                                                                          --

--                         GNAT COMPILER COMPONENTS                         --

--                                                                          --

--                      ADA.EXCEPTIONS.EXCEPTION_TRACES                     --

--                                                                          --

--                                 B o d y                                  --

--                                                                          --

--          Copyright (C) 1992-2009, 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- --

-- 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/>.                                          --

--                                                                          --

-- GNAT was originally developed  by the GNAT team at  New York University. --

-- Extensive contributions were provided by Ada Core Technologies Inc.      --

--                                                                          --

------------------------------------------------------------------------------

with Ada.Unchecked_Conversion;

pragma Warnings (Off);

with Ada.Exceptions.Last_Chance_Handler;

pragma Warnings (On);

--  Bring last chance handler into closure

separate (Ada.Exceptions)

package body Exception_Traces is

   Nline : constant String := String'(1 => ASCII.LF);

   --  Convenient shortcut

   type Exception_Action is access procedure (E : Exception_Occurrence);

   Global_Action : Exception_Action := null;

   pragma Export

     (Ada, Global_Action, "__gnat_exception_actions_global_action");

   --  Global action, executed whenever an exception is raised.  Changing the

   --  export name must be coordinated with code in g-excact.adb.

   Raise_Hook_Initialized : Boolean := False;

   pragma Export

     (Ada, Raise_Hook_Initialized, "__gnat_exception_actions_initialized");

   procedure Last_Chance_Handler

     (Except :  Exception_Occurrence);

   pragma Import (C, Last_Chance_Handler, "__gnat_last_chance_handler");

   pragma No_Return (Last_Chance_Handler);

   --  Users can replace the default version of this routine,

   --  Ada.Exceptions.Last_Chance_Handler.

   function To_Action is new Ada.Unchecked_Conversion

     (Raise_Action, Exception_Action);

   -----------------------

   -- Local Subprograms --

   -----------------------

   procedure Notify_Exception (Excep : EOA; Is_Unhandled : Boolean);

   --  Factorizes the common processing for Notify_Handled_Exception and

   --  Notify_Unhandled_Exception. Is_Unhandled is set to True only in the

   --  latter case because Notify_Handled_Exception may be called for an

   --  actually unhandled occurrence in the Front-End-SJLJ case.

   --------------------------------

   -- Import Run-Time C Routines --

   --------------------------------

   --  The purpose of the following pragma Import is to ensure that we

   --  generate appropriate subprogram descriptors for all C routines in

   --  the standard GNAT library that can raise exceptions. This ensures

   --  that the exception propagation can properly find these routines

   pragma Propagate_Exceptions;

   ----------------------

   -- Notify_Exception --

   ----------------------

   procedure Notify_Exception (Excep : EOA; Is_Unhandled : Boolean) is

   begin

      --  Output the exception information required by the Exception_Trace

      --  configuration. Take care not to output information about internal

      --  exceptions.

      --  ??? In the Front-End ZCX case, the traceback entries we have at this

      --  point only include the ones we stored while walking up the stack *up

      --  to the handler*. All the frames above the subprogram in which the

      --  handler is found are missing.

      if not Excep.Id.Not_Handled_By_Others

        and then

          (Exception_Trace = Every_Raise

            or else (Exception_Trace = Unhandled_Raise and then Is_Unhandled))

      then

         --  Exception trace messages need to be protected when several tasks

         --  can issue them at the same time.

         Lock_Task.all;

         To_Stderr (Nline);

         if Is_Unhandled then

            To_Stderr ("Unhandled ");

         end if;

         To_Stderr ("Exception raised");

         To_Stderr (Nline);

         To_Stderr (Tailored_Exception_Information (Excep.all));

         Unlock_Task.all;

      end if;

      --  Call the user-specific actions

      --  ??? We should presumably look at the reraise status here.

      if Raise_Hook_Initialized

        and then Exception_Data_Ptr (Excep.Id).Raise_Hook /= null

      then

         To_Action (Exception_Data_Ptr (Excep.Id).Raise_Hook) (Excep.all);

      end if;

      if Global_Action /= null then

         Global_Action (Excep.all);

      end if;

   end Notify_Exception;

   ------------------------------

   -- Notify_Handled_Exception --

   ------------------------------

   procedure Notify_Handled_Exception is

   begin

      Notify_Exception (Get_Current_Excep.all, Is_Unhandled => False);

   end Notify_Handled_Exception;

   --------------------------------

   -- Notify_Unhandled_Exception --

   --------------------------------

   procedure Notify_Unhandled_Exception is

      Excep : constant EOA := Get_Current_Excep.all;

   begin

      --  Check whether there is any termination handler to be executed for

      --  the environment task, and execute it if needed. Here we handle both

      --  the Abnormal and Unhandled_Exception task termination. Normal

      --  task termination routine is executed elsewhere (either in the

      --  Task_Wrapper or in the Adafinal routine for the environment task).

      Task_Termination_Handler.all (Excep.all);

      Notify_Exception (Excep, Is_Unhandled => True);

      Debug_Unhandled_Exception (SSL.Exception_Data_Ptr (Excep.Id));

   end Notify_Unhandled_Exception;

   -----------------------------------

   -- Unhandled_Exception_Terminate --

   -----------------------------------

   procedure Unhandled_Exception_Terminate is

      Excep : constant EOA := Save_Occurrence (Get_Current_Excep.all.all);

      --  This occurrence will be used to display a message after finalization.

      --  It is necessary to save a copy here, or else the designated value

      --  could be overwritten if an exception is raised during finalization

      --  (even if that exception is caught).

   begin

      Last_Chance_Handler (Excep.all);

   end Unhandled_Exception_Terminate;

   ------------------------------------

   -- Handling GNAT.Exception_Traces --

   ------------------------------------

   --  The bulk of exception traces output is centralized in Notify_Exception,

   --  for both the Handled and Unhandled cases. Extra task specific output is

   --  triggered in the task wrapper for unhandled occurrences in tasks. It is

   --  not performed in this unit to avoid dragging dependencies against the

   --  tasking units here.

   --  We used to rely on the output performed by Unhanded_Exception_Terminate

   --  for the case of an unhandled occurrence in the environment thread, and

   --  the task wrapper was responsible for the whole output in the tasking

   --  case.

   --  This initial scheme had a drawback: the output from Terminate only

   --  occurs after finalization is done, which means possibly never if some

   --  tasks keep hanging around.

   --  The first "presumably obvious" fix consists in moving the Terminate

   --  output before the finalization. It has not been retained because it

   --  introduces annoying changes in output orders when the finalization

   --  itself issues outputs, this also in "regular" cases not resorting to

   --  Exception_Traces.

   --  Today's solution has the advantage of simplicity and better isolates

   --  the Exception_Traces machinery.

   --  It currently outputs the information about unhandled exceptions twice

   --  in the environment thread, once in the notification routine and once in

   --  the termination routine. Avoiding the second output is possible but so

   --  far has been considered undesirable. It would mean changing the order

   --  of outputs between the two runs with or without exception traces, while

   --  it seems preferable to only have additional outputs in the former

   --  case.

end Exception_Traces;