Currently hotspot uses -gstabs as DEBUG_CFLAGS to generate the full debug version of libjvm.so which we also call it as jvmg version. This won't work with gdb on linux amd64 platform since linux amd64 doesn't support stubs debuggable format. We should just change it to use "-g" and let the gcc compiler to decide which format to use. We should do the same thing on x86 as well, however, that will generate very large libjvm.so file (around 150 M) and stabs works well currently with gdb on linux x86, we can keep it as is. But in the future, we should change it to use "-g" even on x86 platforms.
Since PRT does not build jvmg version of libjvm.so for linux amd64, so size won't be a concern.