Okay I now see from "RFR: 8379516: Adjust JVM debug helper exports" what
is being considered.
Thanks,
David
On 11/03/2026 11:35 am, David Holmes wrote:
On 10/03/2026 7:23 pm, Baesken, Matthias wrote:
I'm not sure where this conclusion is coming from. The case in question
was about "debug" but as stated earlier and/or in the JBS issue this is
potentially an issue for any symbol exported from one of the JDK
libraries that clashes with a symbol from the application native code.
Hi David, I think we were running with exported debug-helper
functions on Windows for some years without complains .
And on Linux , there was only this single issue about "debug" . So in
practice it was not THAT bad.
Agreed.
However you are correct, that it *could* clash in some scenarios .
(but all our other exported functions without nice prefix could
clash too)
Separate issue that those unprefixed symbols possibly should not (all)
be exported.
So we have at least two option :
- prefix the names from debug.cpp (jvm_debug_ or something like
this, maybe there are better suggestions)
- use an exported "helper" that references all those little functions
, so that elimination is avoided , e.g.
// just an exported helper; to avoid link time elimination of the
referenced functions
extern "C" JNIEXPORT void JVM_debug_helpers_keeper(void* p1, void*
p2, void* p3, intptr_t ip, oop oh, address adr) {
blob((CodeBlob*)p1);
dump_vtable(adr);
nm(ip);
disnm(ip);
printnm(ip);
universe();
verify();
...........
}
This one is not there to be ever called, just for keeping the
nm/pp/debug etc. functions.
What do you think ?
I'm a little confused. Calling the wrong function because of a name
clash seems quite a different problem from linking stripping out
functions it doesn't realize could be used. Are we using the prefixes
to prevent linker stripping?
Would that JVM_debug_helpers_keeper(...) approach also work on
Windows ?
No idea - sorry.
David
Best regards, Matthias
