gcc 4.3.2 libgcc_s.so exception handling broken?

[xorquewasp at googlemail.com]

On 2009-01-18 07:39:51, Christoph Mallon wrote:
>
> Are more C functions involved? E.g. is the function pointer passed to
> qsort(), which lives in libc, which is not compiled with -fexceptions.
> Look at the stack trace when the exception occurs. In gdb you can use the
> command "catch throw" (sic) to break when an exception gets thrown.
> Conversely you can break at the catcher with "catch catch" (if it gets this
> far).

Unfortunately not. That was the first thing I looked at.

Here's the complete test:

  /* c_function.c */

  #include <stdio.h>

  void
  c_function (void (*func)(int x))
  {
    printf ("-- %s enter\n", __func__);
    func (23);
    printf ("-- %s exit\n", __func__);
  }

  -- ada_main.adb

  with interfaces.c;
  with ada.text_io;

  procedure ada_main is
    package c renames interfaces.c;

    test_error : exception;

    procedure ext_function
      (x : in c.int) is
    begin
      ada.text_io.put_line ("-- ext_function " & c.int'image (x));
      raise test_error;
    end ext_function;

    procedure c_function
      (process : access procedure (x : in c.int));
    pragma import (c, c_function, "c_function");

  begin
    ada.text_io.put_line ("-- ada_main entry");
    c_function (ext_function'access);
  exception
    when test_error =>
      ada.text_io.put_line ("-- ada_main caught test_error");
  end ada_main;

Compilation:

  gcc43 -o c_function.o -c c_function.c -fPIC  -fexceptions -g -W -Werror -Wall -std=c99 -pedantic-errors -Wno-unused-parameter
  gcc43 -shared -Wl,-soname,c_function.so -o c_function.so c_function.o -lc

  gcc43 -o ada_main.o -c ada_main.adb -g -fstack-check -gnatwaleFG -gnatVa -gnato -gnata
  gnatbind ada_main.ali
  gnatlink -o main-dynamic ada_main.ali c_function.so

  gnatbind ada_main.ali
  gnatlink -o main-static ada_main.ali c_function.o

  $ LD_LIBRARY_PATH=. ldd c_function.so
  c_function.so:
    libc.so.6 => /lib/libc.so.6 (0x2807d000)
    libgcc_s.so.1 => /usr/local/lib/gcc-4.2.3/libgcc_s.so.1 (0x28170000)

Test:

  $ ./main-static
  -- ada_main entry
  -- c_function enter
  -- ext_function  23
  -- ada_main caught test_error

  $ LD_LIBRARY_PATH=. ./main-dynamic
  -- ada_main entry
  -- c_function enter
  -- ext_function  23

  raised ADA_MAIN.TEST_ERROR : ada_main.adb:15

  $ LD_LIBRARY_PATH=. gdb68 ./main-dynamic
  (gdb) catch exception
  Catchpoint 1: all Ada exceptions
  (gdb) b __gnat_os_exit
  Breakpoint 2 at 0x805851b: file adaint.c, line 2116.
  (gdb) r
  Catchpoint 1, ADA_MAIN.TEST_ERROR at 0x08049cda in ada_main.ext_function (x=23) at ada_main.adb:15
  15          raise test_error;
  (gdb) bt
  #0  <__gnat_debug_raise_exception> (e=0x8061168) at s-except.adb:48
  #1  0x0804b620 in <__gnat_raise_nodefer_with_msg> (e=0x8061168) at a-except.adb:830
  #2  0x0804b698 in <__gnat_raise_exception> (e=0x8061168, message=0x8061168) at a-except.adb:870
  #3  0x08049cda in ada_main.ext_function (x=23) at ada_main.adb:15
  #4  0x280927ae in c_function (func=0x8049bf8 <ada_main.ext_function>) at c_function.c:9
  #5  0x08049b5c in ada_main () at ada_main.adb:24
  (gdb) c
  Breakpoint 2, __gnat_os_exit (status=1) at adaint.c:2116
  (gdb) bt
  #0  __gnat_os_exit (status=1) at adaint.c:2116
  #1  0x0805a41e in __gnat_unhandled_terminate () at raise.c:78
  #2  0x0805a1f1 in <__gnat_last_chance_handler> (except=@0x8071000) at a-elchha.adb:138
  #3  0x0804ae14 in ada.exceptions.exception_traces.unhandled_exception_terminate () at a-exextr.adb:175
  #4  0x0804aad2 in ada.exceptions.exception_propagation.cleanupunwind_handler (uw_version=1, uw_phases=10, uw_eclass=5138137877735301376, uw_exception=0xa, uw_context=3217024852, uw_argument=0, <uw_exceptionF>=134587758) at a-exexpr.adb:369
  #5  0x0805c282 in _Unwind_ForcedUnwind_Phase2 (exc=0x806f000, context=0xbfbfe754) at ../.././..//gcc-4.3.2/libgcc/../gcc/unwind.inc:168
  #6  0x0805c4d6 in _Unwind_Resume (exc=0x806f000) at ../.././..//gcc-4.3.2/libgcc/../gcc/unwind.inc:237
  #7  0x08049cfa in ada_main.ext_function (x=23) at ada_main.adb:16
  #8  0x280927ae in c_function (func=0x8049bf8 <ada_main.ext_function>) at c_function.c:9
  #9  0x08049b5c in ada_main () at ada_main.adb:24