Re: [patch] Fix oddity in personality routine

On Tue, Nov 17, 2009 at 10:58:00AM +0000, Andrew Haley wrote:
> Jack Howarth wrote:
> > On Mon, Nov 16, 2009 at 07:08:49PM +0000, Andrew Haley wrote:
> >> There's another unwinder?  Gosh.
> >>
> >> Set a bp on '_Jv_Throw' and step through.  You'll need to compile libgcc
> >> with -O0 or you'll go insane.  The unwinder is quite complex, and it takes
> >> a fair while to understand it.
> 
> >    I have added an unwinder_walk.txt attachment to PR41991. It is a walk
> > from the _Jv_Throw breakpoint for ecj1 compiling the testme.java test code
> > with a libgcc compiled with -O0 installed. This is with current gcc trunk
> > using the patch from http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41991#c3
> > compiled on x86_64-apple-darwin9.8.0 to make sure that the FSF libgcc is
> > used. Hopefully a fix can be found in the libjava code that calls the
> > unwinder as fixing this within the unwinder won't help us with darwin10
> > or later.
> 
> There's probably nothing wrong with the libjava code that calls the
> unwinder: after all, it works everywhere else.  I'm betting this is
> bad unwind info.
> 
> Anyway, at least this is a start.  It tells us that the stack is
> walked but no landing pad is found.  We don't know why.
> 
> Andrew.

Andrew,
  In the unwinder walk, are there any particular places where I could
get additional debug information in gdb that would be helpful to diagnose this
issue? Also, what do you make of the fact that the generated libjava Makefile
uses ecjx_LDFLAGS before it is actually assigned...

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41991#c10

Could this sort of problem be caused by a build issue from improper Makefiles?
Andreas suppressed the crash on his machine using the change in
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41991#c3 but that is insufficient
to fix it on either my MacBook Pro or MacPro under either darwin9 or darwin10
(which is odd).
                 Jack