Mixing BC and CNI in the same executable

Sat Jan 23 14:51:00 GMT 2010

> It looks like the problem here is that antlr-runtime.jar.so was built
> with BC, but the java code in your app binary was not. When using
> BC-ABI (and specifically, -findirect-classes), the class$ symbols are
> hidden.
>> Try building the Antlr .so with -findirect-dispatch
> -fno-indirect-classes. This means that it's calls will be made with be
> made with the BC ABI but class references will not - which is probably
> ok most of the time.
>> I'd also build the java code in your app binary with
> -findirect-dispatch -fno-indirect-classes.

Thanks very much for this -- those options got my program to build and
run. However, it falls over during run-time linking. In my C++ code:
34:	int request::process()
35:	{
36:		using namespace org::antlr::runtime;
37:		using namespace java::lang;
38: 
39:		// invoke the parser
40:		stream = new ANTLRInputStream(in_file);
41:		lexer = new cakeJavaLexer((CharStream*) stream);
... the second "new" segfaults. Strangely, the first "new" is okay. The
first is a class from a antlr-runtime.jar.so, whereas the second is in
a .o compiled from local source. They were both compiled with
-findirect-dispatch -fno-indirect-classes.
Program received signal SIGSEGV, Segmentation fault.
0xb6670fb1 in _Jv_ClosureList::registerClosure(java::lang::Class*, void*) ()
 from /usr/lib/libgcj_bc.so.1
(gdb) bt
#0 0xb6670fb1 in _Jv_ClosureList::registerClosure(java::lang::Class*, void*) ()
 from /usr/lib/libgcj_bc.so.1
#1 0xb6639389 in _Jv_Linker::create_error_method(_Jv_Utf8Const*, java::lang::Class*) ()
 from /usr/lib/libgcj_bc.so.1
#2 0xb663b423 in _Jv_Linker::link_symbol_table(java::lang::Class*) () from /usr/lib/libgcj_bc.so.1
#3 0xb663a85c in _Jv_Linker::wait_for_state(java::lang::Class*, int) ()
 from /usr/lib/libgcj_bc.so.1
#4 0xb6674930 in void java::lang::Class::initializeClass() () from /usr/lib/libgcj_bc.so.1
#5 0xb662a018 in _Jv_AllocObjectNoFinalizer () from /usr/lib/libgcj_bc.so.1
#6 0xb662a046 in _Jv_AllocObject () from /usr/lib/libgcj_bc.so.1
#7 0x08052c7b in cake::request::process (this=0xbffff00c) at cake.cpp:41
#8 0x08057a08 in main (argc=2, argv=0xbffff114) at main.cpp:62
Thanks again for any further suggestions! 
(I only just noticed that the BC libgcj is a completely different
shared object... so perhaps mixing ABIs is a non-starter as I feared.)
Stephen