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|
------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- ADA.EXCEPTIONS.EXCEPTION_TRACES --
-- --
-- B o d y --
-- --
-- Copyright (C) 1992-2005, 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 2, 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. See the GNU General Public License --
-- for more details. You should have received a copy of the GNU General --
-- Public License distributed with GNAT; see file COPYING. If not, write --
-- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
-- Boston, MA 02110-1301, USA. --
-- --
-- As a special exception, if other files instantiate generics from this --
-- unit, or you link this unit with other files to produce an executable, --
-- this unit does not by itself cause the resulting executable to be --
-- covered by the GNU General Public License. This exception does not --
-- however invalidate any other reasons why the executable file might be --
-- covered by the GNU Public License. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
with 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 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.
---------------------------------
-- Debugger Interface Routines --
---------------------------------
-- The routines here are null routines that normally have no effect.
-- They are provided for the debugger to place breakpoints on their
-- entry points to get control on an exception.
procedure Unhandled_Exception;
pragma Export (C, Unhandled_Exception, "__gnat_unhandled_exception");
-- Hook for GDB to support "break exception unhandled"
-- For "break exception", GDB uses __gnat_raise_nodefer_with_msg, which
-- is not in this section because it functions as more than simply a
-- debugger interface.
--------------------------------
-- 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
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));
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);
Unhandled_Exception;
end Notify_Unhandled_Exception;
-------------------------
-- Unhandled_Exception --
-------------------------
procedure Unhandled_Exception is
begin
null;
end 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 preferrable to only have additional outputs in the former
-- case.
end Exception_Traces;
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