Re: The exception bug in egcs-970929

[Andreas Schwab <schwab at issan dot informatik dot uni-dortmund dot de>]

H J Lu <hjl@lucon.org> writes:

|> This code is miscompiled with -O and dwarf based exception on x86.
|> # gcc -O des.cc
|> # a.out
|> zsh: 26333 segmentation fault  ./a.out

|> If dwarf based exception is not used, everything is fine. Somehow
|> g++ adjusts stack twice when calling destructor.

I have just sent this to Kenner for gcc2:

The FDE insns that belong to a specific pc value always come after a
DW_CFA_advance_loc that advances to that pc value.  Thus when
__frame_state_for executes the FDE insns it must still do that if the
current pc value equals the target pc value.

1997-10-04  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>

	* frame.c (__frame_state_for): Execute the FDE insns until the
	current pc value is strictly bigger than the target pc value.

*** testgcc-970926/frame.c.~1~	Wed Sep 24 23:05:26 1997
--- testgcc-970926/frame.c	Sat Oct  4 18:43:39 1997
*************** __frame_state_for (void *pc_target, stru
*** 600,606 ****
    /* Then the insns in the FDE up to our target PC.  */
    end = next_fde (f);
    pc = f->pc_begin;
!   while (insn < end && pc < pc_target)
      insn = execute_cfa_insn (insn, &state, &info, &pc);
  
    memcpy (state_in, &state.s, sizeof (state.s));
--- 600,606 ----
    /* Then the insns in the FDE up to our target PC.  */
    end = next_fde (f);
    pc = f->pc_begin;
!   while (insn < end && pc <= pc_target)
      insn = execute_cfa_insn (insn, &state, &info, &pc);
  
    memcpy (state_in, &state.s, sizeof (state.s));

-- 
Andreas Schwab                                      "And now for something
schwab@issan.informatik.uni-dortmund.de              completely different"