[Bug libgcj/13708] java program crashes at startup, UTF-8 environment

["mec dot gnu at mindspring dot com" <gcc-bugzilla at gcc dot gnu dot org>]

------- Additional Comments From mec dot gnu at mindspring dot com  2004-01-17 10:11 -------
Subject: Re:  java program crashes at startup, UTF-8 environment

Some more info:

Did I mention that I configure my toolchains with --disable-shared?
I bet that's why I encountered the bug and nobody else has.

Try building gcc HEAD with "--disable-shared".  Or just use a normal
toolchain and build the Java executable with "-static".  Both ways
produce the segfault for me.

It appears that the initialization procedure is different for
shared libraries versus unshared archive libraries.

Also, I date-searched the regression to this patch:

  2004-01-14  Nathan Bryant  <nbryant@optonline.net>
	     Tom Tromey  <tromey@redhat.com>

	 PR libgcj/12001:
	 * gnu/gcj/runtime/VMClassLoader.java (VMClassLoader): Pass empty
	 array to superclass.
	 (init): Changed interface; add URLs here.
	 (initialize): New static method.
	 * prims.cc (_Jv_CreateJavaVM): Initialize ClassLoader here...
	 (_Jv_RunMain): ... not here.

This matches the stack backtraces and the gdb traces that I saw:

  VMClassLoader.getSystemClassLoader calls System.getProperty
  class initialization for System constructs three standard PrintStream's.
  java.io.PrintStream.PrintStream calls Unicode stuff
  Unicode stuff wants to use a class loader

Have a look at _Jv_FindClass.  _Jv_FindClass calls _Jv_FindClassInCache,
which returns a non-null klass if the class has been "loaded"
or "initiated".  With a shared library, I suspect that all the classes
are getting "loaded" or "initiated" at the same time; with a static
library, the class "gnu.gcj.convertOutput_UTF8" is definitely not
"loaded" and not "initiated".  I don't know the meanings of "loaded"
and "initiated" so I can't say more than that.

Anyways, link the program with "-static", and be sure to run with
LANG=en_US.UTF-8, and you ought to see the segfault in _Jv_FindClass.

Michael C


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13708