+++ /dev/null
-------------------------------------------------------------------------------
--- --
--- GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS --
--- --
--- S Y S T E M . T A S K I N G . D E B U G --
--- --
--- S p e c --
--- --
--- $Revision: 1.3.10.1 $
--- --
--- Copyright (C) 1997-2001, 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 2, or (at your option) any later ver- --
--- sion. GNARL 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 GNARL; see file COPYING. If not, write --
--- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
--- MA 02111-1307, 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. --
--- --
--- GNARL was developed by the GNARL team at Florida State University. --
--- Extensive contributions were provided by Ada Core Technologies Inc. --
--- --
-------------------------------------------------------------------------------
-
--- This package encapsulates all direct interfaces to task debugging services
--- that are needed by gdb with gnat mode (1.17 and higher)
-
-with Interfaces.C;
-with System.Tasking;
-with System.OS_Interface;
-
-package System.Tasking.Debug is
-
- subtype int is Interfaces.C.int;
- subtype unsigned_long is Interfaces.C.unsigned_long;
-
- package ST renames System.Tasking;
-
- Known_Tasks : array (0 .. 999) of Task_ID;
- -- Global array of tasks read by gdb, and updated by
- -- Create_Task and Finalize_TCB
-
- procedure Task_Creation_Hook (Thread : OS_Interface.Thread_Id);
- -- This procedure is used to notify VxGdb of task's creation.
- -- It must be called by the task's creator.
-
- procedure Task_Termination_Hook;
- -- This procedure is used to notify VxGdb of task's termination.
-
- function Self return Task_ID;
- -- return system ID of current task
-
- procedure List_Tasks;
- -- Print a list of all the known Ada tasks with abbreviated state
- -- information, one-per-line, to the standard output file
-
- procedure Print_Current_Task;
- procedure Print_Task_Info_Header;
- procedure Print_Task_Info (T : Task_ID);
- -- Write TASK_ID of current task, in hexadecimal, as one line, to
- -- the standard output file
- --
- -- Beware that Print_Current_Task may print garbage during an early
- -- stage of activation. There is a small window where a task is just
- -- initializing itself and has not yet recorded its own task Id.
- --
- -- Beware that Print_Current_Task will either not work at all or print
- -- garbage if it has interrupted a thread of control that does not
- -- correspond to any Ada task. For example, this is could happen if
- -- the debugger interrupts a signal handler that is using an alternate
- -- stack, or interrupts the dispatcher in the underlying thread
- -- implementation.
-
- procedure Set_User_State (Value : Integer);
-
- procedure Print_Accept_Info (T : Task_ID);
-
- procedure Trace
- (Self_ID : Task_ID;
- Msg : String;
- Other_ID : Task_ID;
- Flag : Character);
-
- procedure Trace
- (Self_ID : Task_ID;
- Msg : String;
- Flag : Character);
-
- procedure Trace
- (Msg : String;
- Flag : Character);
-
- procedure Trace
- (Msg : String;
- Other_ID : Task_ID;
- Flag : Character);
-
- procedure Set_Trace
- (Flag : Character;
- Value : Boolean := True);
-
- function Image (T : Task_ID) return String;
-
- procedure Suspend_All_Tasks (Thread_Self : OS_Interface.Thread_Id);
- -- Suspend all the tasks except the one whose associated thread is
- -- Thread_Self by traversing All_Tasks_Lists and calling
- -- System.Task_Primitives.Operations.Suspend_Task
- -- Such functionality is needed by gdb on some targets (e.g VxWorks)
- -- Warning: for efficiency purposes, there is no locking.
-
- procedure Resume_All_Tasks (Thread_Self : OS_Interface.Thread_Id);
- -- Resume all the tasks except the one whose associated thread is
- -- Thread_Self by traversing All_Tasks_Lists and calling
- -- System.Task_Primitives.Operations.Continue_Task
- -- Such functionality is needed by gdb on some targets (e.g VxWorks)
- -- Warning: for efficiency purposes, there is no locking.
-
-end System.Tasking.Debug;
-
------------------------------
--- Use of These Functions --
------------------------------
-
--- Calling complicated functions from the debugger is generally pretty
--- risky, especially in a multithreaded program.
-
--- The debugger may interrupt something that is not an Ada task,
--- within the thread implementation, and which is not async-safe.
-
--- For example, under Solaris, it can interrupt code in "_dynamiclwps",
--- which seems to serve as dispatcher when all the user threads are
--- suspended. By experience, we have found that one cannot safely
--- do certain things, apparently including calls to thread primitives
--- from the debugger if the debugger has interrupted at one of these
--- unsafe points. In general, if you interrupt a running program
--- asynchronously (e.g. via control-C), it will not be safe to
--- call the subprograms in this package.
-
------------------
--- Future work --
------------------
-
--- It would be nice to be able to tell whether execution has been
--- interrupted in an Ada task. A heuristic way of checking this would
--- be if we added to the Ada TCB a component that always contains a
--- constant value that is unlikely to occur accidentally in code or
--- data. We could then check this in the debugger-callable subprograms,
--- and simply return an error code if it looks unsafe to proceed.
-
--- ???
--- Recently we have added such a marker as a local variable of the
--- task-wrapper routine. This allows Self to generate a fake ATCB for
--- non-Ada threads of control. Given this capability, it is probably
--- time to revisit the issue above.
-
--- DEADLOCK
-
--- We follow a simple rule here to avoid deadlock:
-
--- We do not use any locks in functions called by gdb, and we do not
--- traverse linked lists.
---
--- The use of an array (Known_Tasks) has many advantages:
-
--- - Easy and fast to examine;
--- - No risk of dangling references (to the next element) when traversing
--- the array.
projects / msp430-gcc.git / blobdiff