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) 1992-2009, 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 System.Storage_Elements;  use System.Storage_Elements;
  36
  37 pragma Warnings (Off);
  38 --  Since several constructs give warnings in 3.14a1, including unreferenced
  39 --  variables and pragma Unreferenced itself.
  40
  41 separate (Ada.Exceptions)
  42 package body Exception_Propagation is
  43
  44    ---------------------
  45    -- Setup_Exception --
  46    ---------------------
  47
  48    procedure Setup_Exception
  49      (Excep    : EOA;
  50       Current  : EOA;
  51       Reraised : Boolean := False)
  52    is
  53       pragma Unreferenced (Excep, Current, Reraised);
  54    begin
  55       --  In the GNAT-SJLJ case this "stack" only exists implicitly, by way of
  56       --  local occurrence declarations together with save/restore operations
  57       --  generated by the front-end, and this routine has nothing to do.
  58
  59       null;
  60    end Setup_Exception;
  61
  62    -------------------------
  63    -- Propagate_Exception --
  64    -------------------------
  65
  66    procedure Propagate_Exception
  67      (E                   : Exception_Id;
  68       From_Signal_Handler : Boolean)
  69    is
  70       pragma Inspection_Point (E);
  71
  72       Jumpbuf_Ptr : constant Address := Get_Jmpbuf_Address.all;
  73       Excep       : constant EOA := Get_Current_Excep.all;
  74    begin
  75       --  Compute the backtrace for this occurrence if corresponding binder
  76       --  option has been set. Call_Chain takes care of the reraise case.
  77
  78       Call_Chain (Excep);
  79
  80       --  Note on above call to Call_Chain:
  81
  82       --  We used to only do this if From_Signal_Handler was not set,
  83       --  based on the assumption that backtracing from a signal handler
  84       --  would not work due to stack layout oddities. However, since
  85
  86       --   1. The flag is never set in tasking programs (Notify_Exception
  87       --      performs regular raise statements), and
  88
  89       --   2. No problem has shown up in tasking programs around here so
  90       --      far, this turned out to be too strong an assumption.
  91
  92       --  As, in addition, the test was
  93
  94       --   1. preventing the production of backtraces in non-tasking
  95       --      programs, and
  96
  97       --   2. introducing a behavior inconsistency between
  98       --      the tasking and non-tasking cases,
  99
 100       --  we have simply removed it
 101
 102       --  If the jump buffer pointer is non-null, transfer control using
 103       --  it. Otherwise announce an unhandled exception (note that this
 104       --  means that we have no finalizations to do other than at the outer
 105       --  level). Perform the necessary notification tasks in both cases.
 106
 107       if Jumpbuf_Ptr /= Null_Address then
 108          if not Excep.Exception_Raised then
 109             Excep.Exception_Raised := True;
 110             Exception_Traces.Notify_Handled_Exception;
 111          end if;
 112
 113          builtin_longjmp (To_Jmpbuf_Address (Jumpbuf_Ptr), 1);
 114
 115       else
 116          Exception_Traces.Notify_Unhandled_Exception;
 117          Exception_Traces.Unhandled_Exception_Terminate;
 118       end if;
 119    end Propagate_Exception;
 120
 121 end Exception_Propagation;