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Re: [patch/rfa] Signal trampoline unwinder for hppa-hpux
On Tue, May 25, 2004 at 10:36:09PM -0700, Randolph Chung wrote:
> > Yes, definitly. Having to do instruction examination should be
> > considered a last resource.
>
> ok, this is checked in now too, but can someone please comment on this
> bit:
>
> ================================================================
> Unfortunately this still fails a lot of the signal related testcases.
> It is not because of a problem with the signal unwinder though:
>
> On HPUX-SOM, there is an export stub inserted into the call sequence in
> some cases; the export stub is hit on the return path from indirect
> function calls, and apparently on return from a signal handler. This
> creates an extra frame in the backtrace, viz:
>
> (gdb) bt
> #0 0x000029e4 in handle_USR1 (sig=0)
> at ../../../gdb/gdb/testsuite/gdb.base/annota1.c:18
> #1 0x000029c8 in handle_USR1 ()
> at ../../../gdb/gdb/testsuite/gdb.base/annota1.c:17
> #2 <signal handler called>
> #3 main () at ../../../gdb/gdb/testsuite/gdb.base/annota1.c:40
>
> Frame 1 comes from the export stub. Because of this, the pattern
> matching in the backtrace test fails. I am not sure if this is a
> problem with the test script or with the handling of export stubs -- am
> I supposed to somehow supress the export stub from showing up in the
> backtrace? (if so, how?)
Right now, we don't have any mechanism to hide frames. I'm not sure
whether it's a desirable feature or not. I've wanted it for C++
occasionally.
I wonder if GDB should have a single knob to switch between
"simplified" and more thorough/accurate display modes? Could any of
the existing toggles be added to this?
--
Daniel Jacobowitz