gcc/ada/a-exexpr.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --  A D A . E X C E P T I O N S . E X C E P T I O N _ P R O P A G A T I O N --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2011, Free Software Foundation, Inc.         --
  10 --                                                                          --
  11 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  12 -- terms of the  GNU General Public License as published  by the Free Soft- --
  13 -- ware  Foundation;  either version 3,  or (at your option) any later ver- --
  14 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  15 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  16 -- or FITNESS FOR A PARTICULAR PURPOSE.                                     --
  17 --                                                                          --
  18 -- As a special exception under Section 7 of GPL version 3, you are granted --
  19 -- additional permissions described in the GCC Runtime Library Exception,   --
  20 -- version 3.1, as published by the Free Software Foundation.               --
  21 --                                                                          --
  22 -- You should have received a copy of the GNU General Public License and    --
  23 -- a copy of the GCC Runtime Library Exception along with this program;     --
  24 -- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
  25 -- <http://www.gnu.org/licenses/>.                                          --
  26 --                                                                          --
  27 -- GNAT was originally developed  by the GNAT team at  New York University. --
  28 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  29 --                                                                          --
  30 ------------------------------------------------------------------------------
  31
  32 --  This is the default version, using the __builtin_setjmp/longjmp EH
  33 --  mechanism.
  34
  35 with Ada.Unchecked_Conversion;
  36
  37 separate (Ada.Exceptions)
  38 package body Exception_Propagation is
  39
  40    --  Common binding to __builtin_longjmp for sjlj variants.
  41
  42    procedure builtin_longjmp (buffer : System.Address; Flag : Integer);
  43    pragma No_Return (builtin_longjmp);
  44    pragma Import (Intrinsic, builtin_longjmp, "__builtin_longjmp");
  45
  46    -------------------------
  47    -- Propagate_Exception --
  48    -------------------------
  49
  50    procedure Propagate_Exception
  51    is
  52       Jumpbuf_Ptr : constant Address := Get_Jmpbuf_Address.all;
  53       Excep       : constant EOA := Get_Current_Excep.all;
  54    begin
  55       --  Compute the backtrace for this occurrence if corresponding binder
  56       --  option has been set. Call_Chain takes care of the reraise case.
  57
  58       Call_Chain (Excep);
  59
  60       --  Note on above call to Call_Chain:
  61
  62       --  We used to only do this if From_Signal_Handler was not set,
  63       --  based on the assumption that backtracing from a signal handler
  64       --  would not work due to stack layout oddities. However, since
  65
  66       --   1. The flag is never set in tasking programs (Notify_Exception
  67       --      performs regular raise statements), and
  68
  69       --   2. No problem has shown up in tasking programs around here so
  70       --      far, this turned out to be too strong an assumption.
  71
  72       --  As, in addition, the test was
  73
  74       --   1. preventing the production of backtraces in non-tasking
  75       --      programs, and
  76
  77       --   2. introducing a behavior inconsistency between
  78       --      the tasking and non-tasking cases,
  79
  80       --  we have simply removed it
  81
  82       --  If the jump buffer pointer is non-null, transfer control using
  83       --  it. Otherwise announce an unhandled exception (note that this
  84       --  means that we have no finalizations to do other than at the outer
  85       --  level). Perform the necessary notification tasks in both cases.
  86
  87       if Jumpbuf_Ptr /= Null_Address then
  88          if not Excep.Exception_Raised then
  89             Excep.Exception_Raised := True;
  90             Exception_Traces.Notify_Handled_Exception;
  91          end if;
  92
  93          builtin_longjmp (Jumpbuf_Ptr, 1);
  94
  95       else
  96          Exception_Traces.Notify_Unhandled_Exception;
  97          Exception_Traces.Unhandled_Exception_Terminate;
  98       end if;
  99    end Propagate_Exception;
 100
 101 end Exception_Propagation;