gcc/ada/a-elchha.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT RUN-TIME COMPONENTS                         --
   4 --                                                                          --
   5 --    A D A . E X C E P T I O N S . L A S T _ C H A N C E _ H A N D L E R   --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --          Copyright (C) 2003-2005, Free Software Foundation, Inc.         --
  10 --                                                                          --
  11 -- This specification is derived from the Ada Reference Manual for use with --
  12 -- GNAT. The copyright notice above, and the license provisions that follow --
  13 -- apply solely to the  contents of the part following the private keyword. --
  14 --                                                                          --
  15 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  16 -- terms of the  GNU General Public License as published  by the Free Soft- --
  17 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  18 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  19 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  20 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  21 -- for  more details.  You should have  received  a copy of the GNU General --
  22 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  23 -- to  the  Free Software Foundation,  51  Franklin  Street,  Fifth  Floor, --
  24 -- Boston, MA 02110-1301, USA.                                              --
  25 --                                                                          --
  26 -- As a special exception,  if other files  instantiate  generics from this --
  27 -- unit, or you link  this unit with other files  to produce an executable, --
  28 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  29 -- covered  by the  GNU  General  Public  License.  This exception does not --
  30 -- however invalidate  any other reasons why  the executable file  might be --
  31 -- covered by the  GNU Public License.                                      --
  32 --                                                                          --
  33 -- GNAT was originally developed  by the GNAT team at  New York University. --
  34 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  35 --                                                                          --
  36 ------------------------------------------------------------------------------
  37
  38 --  Default version for most targets
  39
  40 with System.Standard_Library; use System.Standard_Library;
  41 --  Used for Adafinal
  42
  43 with System.Soft_Links;
  44 --  Used for Task_Termination_Handler
  45 --           Task_Termination_NT
  46
  47 procedure Ada.Exceptions.Last_Chance_Handler
  48   (Except : Exception_Occurrence)
  49 is
  50    procedure Unhandled_Terminate;
  51    pragma No_Return (Unhandled_Terminate);
  52    pragma Import (C, Unhandled_Terminate, "__gnat_unhandled_terminate");
  53    --  Perform system dependent shutdown code
  54
  55    function Exception_Message_Length
  56      (X : Exception_Occurrence) return Natural;
  57    pragma Import (Ada, Exception_Message_Length, "__gnat_exception_msg_len");
  58
  59    procedure Append_Info_Exception_Message
  60      (X : Exception_Occurrence; Info : in out String; Ptr : in out Natural);
  61    pragma Import
  62      (Ada, Append_Info_Exception_Message, "__gnat_append_info_e_msg");
  63
  64    procedure Append_Info_Exception_Information
  65      (X : Exception_Occurrence; Info : in out String; Ptr : in out Natural);
  66    pragma Import
  67      (Ada, Append_Info_Exception_Information, "__gnat_append_info_e_info");
  68
  69    procedure To_Stderr (S : String);
  70    pragma Import (Ada, To_Stderr, "__gnat_to_stderr");
  71    --  Little routine to output string to stderr
  72
  73    Ptr   : Natural := 0;
  74    Nobuf : String (1 .. 0);
  75
  76    Nline : constant String := String'(1 => ASCII.LF);
  77    --  Convenient shortcut
  78
  79 begin
  80    --  Do not execute any task termination code when shutting down the system.
  81    --  The Adafinal procedure would execute the task termination routine for
  82    --  normal termination, but we have already executed the task termination
  83    --  procedure because of an unhandled exception.
  84
  85    System.Soft_Links.Task_Termination_Handler :=
  86      System.Soft_Links.Task_Termination_NT'Access;
  87
  88    --  Let's shutdown the runtime now. The rest of the procedure needs to be
  89    --  careful not to use anything that would require runtime support. In
  90    --  particular, functions returning strings are banned since the sec stack
  91    --  is no longer functional. This is particularly important to note for the
  92    --  Exception_Information output. We used to allow the tailored version to
  93    --  show up here, which turned out to be a bad idea as it might involve a
  94    --  traceback decorator the length of which we don't control. Potentially
  95    --  heavy primary/secondary stack use or dynamic allocations right before
  96    --  this point are not welcome, moving the output before the finalization
  97    --  raises order of outputs concerns, and decorators are intended to only
  98    --  be used with exception traces, which should have been issued already.
  99
 100    System.Standard_Library.Adafinal;
 101
 102    --  Check for special case of raising _ABORT_SIGNAL, which is not
 103    --  really an exception at all. We recognize this by the fact that
 104    --  it is the only exception whose name starts with underscore.
 105
 106    if To_Ptr (Except.Id.Full_Name) (1) = '_' then
 107       To_Stderr (Nline);
 108       To_Stderr ("Execution terminated by abort of environment task");
 109       To_Stderr (Nline);
 110
 111    --  If no tracebacks, we print the unhandled exception in the old style
 112    --  (i.e. the style used before ZCX was implemented). We do this to
 113    --  retain compatibility.
 114
 115    elsif Except.Num_Tracebacks = 0 then
 116       To_Stderr (Nline);
 117       To_Stderr ("raised ");
 118       To_Stderr
 119         (To_Ptr (Except.Id.Full_Name) (1 .. Except.Id.Name_Length - 1));
 120
 121       if Exception_Message_Length (Except) /= 0 then
 122          To_Stderr (" : ");
 123          Append_Info_Exception_Message (Except, Nobuf, Ptr);
 124       end if;
 125
 126       To_Stderr (Nline);
 127
 128    --  Traceback exists
 129
 130    else
 131       To_Stderr (Nline);
 132       To_Stderr ("Execution terminated by unhandled exception");
 133       To_Stderr (Nline);
 134
 135       Append_Info_Exception_Information (Except, Nobuf, Ptr);
 136    end if;
 137
 138    Unhandled_Terminate;
 139 end Ada.Exceptions.Last_Chance_Handler;