gcc/ada/libgnat/a-excach.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --             A D A . E X C E P T I O N S . C A L L _ C H A I N            --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2020, 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 pragma Warnings (Off);
  33 --  Allow withing of non-Preelaborated units in Ada 2005 mode where this
  34 --  package will be categorized as Preelaborate. See AI-362 for details.
  35 --  It is safe in the context of the run-time to violate the rules.
  36
  37 with System.Traceback;
  38
  39 pragma Warnings (On);
  40
  41 separate (Ada.Exceptions)
  42 procedure Call_Chain (Excep : EOA) is
  43
  44    Exception_Tracebacks : Integer;
  45    pragma Import (C, Exception_Tracebacks, "__gl_exception_tracebacks");
  46    --  Boolean indicating whether tracebacks should be stored in exception
  47    --  occurrences.
  48
  49 begin
  50    if Exception_Tracebacks /= 0 and Excep.Num_Tracebacks = 0 then
  51
  52       --  If Exception_Tracebacks = 0 then the program was not
  53       --  compiled for storing tracebacks in exception occurrences
  54       --  (-bargs -E switch) so that we do not generate them.
  55       --
  56       --  If Excep.Num_Tracebacks /= 0 then this is a reraise, no need
  57       --  to store a new (wrong) chain.
  58
  59       --  We ask System.Traceback.Call_Chain to skip 3 frames to ensure that
  60       --  itself, ourselves and our caller are not part of the result. Our
  61       --  caller is always an exception propagation actor that we don't want
  62       --  to see, and it may be part of a separate subunit which pulls it
  63       --  outside the AAA/ZZZ range.
  64
  65       System.Traceback.Call_Chain
  66         (Traceback   => Excep.Tracebacks,
  67          Max_Len     => Max_Tracebacks,
  68          Len         => Excep.Num_Tracebacks,
  69          Exclude_Min => Code_Address_For_AAA,
  70          Exclude_Max => Code_Address_For_ZZZ,
  71          Skip_Frames => 3);
  72    end if;
  73
  74 end Call_Chain;