void doit() {
ResourceMark rmark; // _thread != Thread::current()
RegisterMap rm(_thread, false);
// There can be a race condition between a VM_Operation reaching a safepoint
// and the target thread exiting from Java execution.
// We must recheck the last Java frame still exists.
if (!_thread->is_exiting() && _thread->has_last_Java_frame()) {
javaVFrame* vf = _thread->last_java_vframe(&rm);
assert(vf != NULL, "must have last java frame");
Method* method = vf->method();
_method_id = method->jmethod_id();
_bci = vf->bci();
} else {
// Clear current location as the target thread has no Java frames anymore.
_method_id = (jmethodID)NULL;
_bci = 0;
}
}
jvmtiError
JvmtiEnvBase::get_frame_location(JavaThread *java_thread, jint depth,
jmethodID* method_ptr, jlocation* location_ptr) {
#ifdef ASSERT
uint32_t debug_bits = 0;
#endif
assert((SafepointSynchronize::is_at_safepoint() ||
is_thread_fully_suspended(java_thread, false, &debug_bits)),
"at safepoint or target thread is suspended");
Thread* current_thread = Thread::current();
ResourceMark rm(current_thread);
vframe *vf = vframeFor(java_thread, depth);
if (vf == NULL) {
return JVMTI_ERROR_NO_MORE_FRAMES;
}
// vframeFor should return a java frame. If it doesn't
// it means we've got an internal error and we return the
// error in product mode. In debug mode we will instead
// attempt to cast the vframe to a javaVFrame and will
// cause an assertion/crash to allow further diagnosis.
#ifdef PRODUCT
if (!vf->is_java_frame()) {
return JVMTI_ERROR_INTERNAL;
}
#endif
HandleMark hm(current_thread);
javaVFrame *jvf = javaVFrame::cast(vf);
Method* method = jvf->method();
if (method->is_native()) {
*location_ptr = -1;
} else {
*location_ptr = jvf->bci();
}
*method_ptr = method->jmethod_id();
return JVMTI_ERROR_NONE;
}
