Re: Core dump (Illegal instruction) with crosstool's GCJ

[Martin Egholm Nielsen <martin at egholm-nielsen dot dk>]

Hi Dan,

> > Until recently I only had problems when I trying to compile any small 
> > Java-source with "-static". Applications linked like that wouldn't 
> > execute on the target and would cause a core dump immediately after 
> > start (signal 4, Illegal instruction).
> Please check http://gcc.gnu.org/ml/java/ and http://gcc.gnu.org/bugzilla/
> to see if similar problems have been reported there.  If not,
> go ahead and report it (either place is fine; maybe informally on
> the mailing list, then if that doesn't work, formally in the bug tracking
> system.)  
I've checked the archives, and cannot find anything resembling it...

> It's worth fixing.
Indeed it is...

Overnight I've compiled crosstool with gcc-3.3.3-glibc-2.2.5.dat for 
ppc405, and now I can actually make static-linked programs. However, the 
faulty application is still faulty....

> > However, now I've have a small test-example (dynamically linked) using 
> > the java.lang.reflect.Proxy-class, that'll fail consequently (Illegal 
> > instruction) performing some specific Java-action.
> > I've tried the same application with gcj-3.4 under MinGW and gcj-3.3.1 
> > under Cygwin, and here it works.
> > Any ideas to how to overcome this problem?
> > The crosscompiler has been build on cygwin with crosstool-0.28-rc13 
> > with the for the ppc405-target with gcc-3.4.0-glibc-2.2.5.dat.
> > A similar compiler has been created under my RedHat, and also a 
> > cygwin-compiler with glibc-2.3.2.
> > The target system runs the a root-filesystem from ELDK 2.0.2 (or maybe 
> > 2.2.0) from Denx Software, and the kernel is a patched 2.4.20 from 
> > DAVE (http://www.dave-tech.it/) specific for my PPChameleonEVB-board.
> So you're having trouble only on the ppc405, eh?
Yes...

> And it happens regardless of the build system type,
> and regardless of the glibc version?  
Well, I have only tested it on my RedHat and in my Cygwin, and with 
glibc-2.2.5 with both, but only glibc-2.3.2 from Cygwin.
I've then copied the entire lib-directory from crosstool onto target 
(NFS) and set LD_LIBRARY_PATH when trying to execute the gcj-applications.
As mentioned in another thread, I haven't been able to recompile my 
kernel with crosstool, so I don't hope that matters.

> It does rather sound like a gcj bug.
I'm not able to tell where the bug may be...
Can the core-dump be of any help? Any commands I can issue in gdb 
that'll say anything usefull?

> It might be worth verifying that the bug happens even if you
> compile the java source using sun's compiler, and then just
> use gcj to compile the .jar file.  This will help isolate
> the problem.
I've tried compiling the source with both Sun's compiler, and IBM's 
compiler from Eclipse. This makes no difference...

> Once you've done that, the best thing is probably to submit a bug report.
> In both cases please attach the source code in question
> trimmed down to the bone (the smaller the better, no extra
> prints if possible) so the resulting assembly is easier to read.
I'll do that...

Best regards,
 Martin



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