/*
* Copyright (c) 2003, 2015, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*
*/
#include "precompiled.hpp"
#include "gc/shared/gcLocker.hpp"
#include "jvmtifiles/jvmtiEnv.hpp"
#include "memory/resourceArea.hpp"
#include "prims/jvmtiEventController.inline.hpp"
#include "prims/jvmtiImpl.hpp"
#include "prims/jvmtiThreadState.inline.hpp"
#include "runtime/vframe.hpp"
// marker for when the stack depth has been reset and is now unknown.
// any negative number would work but small ones might obscure an
// underrun error.
static const int UNKNOWN_STACK_DEPTH = -99;
///////////////////////////////////////////////////////////////
//
// class JvmtiThreadState
//
// Instances of JvmtiThreadState hang off of each thread.
// Thread local storage for JVMTI.
//
JvmtiThreadState *JvmtiThreadState::_head = NULL;
JvmtiThreadState::JvmtiThreadState(JavaThread* thread)
: _thread_event_enable() {
assert(JvmtiThreadState_lock->is_locked(), "sanity check");
_thread = thread;
_exception_state = ES_CLEARED;
_debuggable = true;
_hide_single_stepping = false;
_hide_level = 0;
_pending_step_for_popframe = false;
_class_being_redefined = NULL;
_class_load_kind = jvmti_class_load_kind_load;
_head_env_thread_state = NULL;
_dynamic_code_event_collector = NULL;
_vm_object_alloc_event_collector = NULL;
_the_class_for_redefinition_verification = NULL;
_scratch_class_for_redefinition_verification = NULL;
_cur_stack_depth = UNKNOWN_STACK_DEPTH;
// JVMTI ForceEarlyReturn support
_pending_step_for_earlyret = false;
_earlyret_state = earlyret_inactive;
_earlyret_tos = ilgl;
_earlyret_value.j = 0L;
_earlyret_oop = NULL;
// add all the JvmtiEnvThreadState to the new JvmtiThreadState
{
JvmtiEnvIterator it;
for (JvmtiEnvBase* env = it.first(); env != NULL; env = it.next(env)) {
if (env->is_valid()) {
add_env(env);
}
}
}
// link us into the list
{
// The thread state list manipulation code must not have safepoints.
// See periodic_clean_up().
debug_only(NoSafepointVerifier nosafepoint;)
_prev = NULL;
_next = _head;
if (_head != NULL) {
_head->_prev = this;
}
_head = this;
}
// set this as the state for the thread
thread->set_jvmti_thread_state(this);
}
JvmtiThreadState::~JvmtiThreadState() {
assert(JvmtiThreadState_lock->is_locked(), "sanity check");
// clear this as the state for the thread
get_thread()->set_jvmti_thread_state(NULL);
// zap our env thread states
{
JvmtiEnvBase::entering_dying_thread_env_iteration();
JvmtiEnvThreadStateIterator it(this);
for (JvmtiEnvThreadState* ets = it.first(); ets != NULL; ) {
JvmtiEnvThreadState* zap = ets;
ets = it.next(ets);
delete zap;
}
JvmtiEnvBase::leaving_dying_thread_env_iteration();
}
// remove us from the list
{
// The thread state list manipulation code must not have safepoints.
// See periodic_clean_up().
debug_only(NoSafepointVerifier nosafepoint;)
if (_prev == NULL) {
assert(_head == this, "sanity check");
_head = _next;
} else {
assert(_head != this, "sanity check");
_prev->_next = _next;
}
if (_next != NULL) {
_next->_prev = _prev;
}
_next = NULL;
_prev = NULL;
}
}
void
JvmtiThreadState::periodic_clean_up() {
assert(SafepointSynchronize::is_at_safepoint(), "at safepoint");
// This iteration is initialized with "_head" instead of "JvmtiThreadState::first()"
// because the latter requires the JvmtiThreadState_lock.
// This iteration is safe at a safepoint as well, see the NoSafepointVerifier
// asserts at all list manipulation sites.
for (JvmtiThreadState *state = _head; state != NULL; state = state->next()) {
// For each environment thread state corresponding to an invalid environment
// unlink it from the list and deallocate it.
JvmtiEnvThreadStateIterator it(state);
JvmtiEnvThreadState* previous_ets = NULL;
JvmtiEnvThreadState* ets = it.first();
while (ets != NULL) {
if (ets->get_env()->is_valid()) {
previous_ets = ets;
ets = it.next(ets);
} else {
// This one isn't valid, remove it from the list and deallocate it
JvmtiEnvThreadState* defunct_ets = ets;
ets = ets->next();
if (previous_ets == NULL) {
assert(state->head_env_thread_state() == defunct_ets, "sanity check");
state->set_head_env_thread_state(ets);
} else {
previous_ets->set_next(ets);
}
delete defunct_ets;
}
}
}
}
void JvmtiThreadState::add_env(JvmtiEnvBase *env) {
assert(JvmtiThreadState_lock->is_locked(), "sanity check");
JvmtiEnvThreadState *new_ets = new JvmtiEnvThreadState(_thread, env);
// add this environment thread state to the end of the list (order is important)
{
// list deallocation (which occurs at a safepoint) cannot occur simultaneously
debug_only(NoSafepointVerifier nosafepoint;)
JvmtiEnvThreadStateIterator it(this);
JvmtiEnvThreadState* previous_ets = NULL;
for (JvmtiEnvThreadState* ets = it.first(); ets != NULL; ets = it.next(ets)) {
previous_ets = ets;
}
if (previous_ets == NULL) {
set_head_env_thread_state(new_ets);
} else {
previous_ets->set_next(new_ets);
}
}
}
void JvmtiThreadState::enter_interp_only_mode() {
assert(_thread->get_interp_only_mode() == 0, "entering interp only when mode not zero");
_thread->increment_interp_only_mode();
}
void JvmtiThreadState::leave_interp_only_mode() {
assert(_thread->get_interp_only_mode() == 1, "leaving interp only when mode not one");
_thread->decrement_interp_only_mode();
}
// Helper routine used in several places
int JvmtiThreadState::count_frames() {
guarantee(SafepointSynchronize::is_at_safepoint() ||
(JavaThread *)Thread::current() == get_thread(),
"must be current thread or at safepoint");
if (!get_thread()->has_last_Java_frame()) return 0; // no Java frames
ResourceMark rm;
RegisterMap reg_map(get_thread());
javaVFrame *jvf = get_thread()->last_java_vframe(®_map);
int n = 0;
while (jvf != NULL) {
Method* method = jvf->method();
jvf = jvf->java_sender();
n++;
}
return n;
}
void JvmtiThreadState::invalidate_cur_stack_depth() {
guarantee(SafepointSynchronize::is_at_safepoint() ||
(JavaThread *)Thread::current() == get_thread(),
"must be current thread or at safepoint");
_cur_stack_depth = UNKNOWN_STACK_DEPTH;
}
void JvmtiThreadState::incr_cur_stack_depth() {
guarantee(JavaThread::current() == get_thread(), "must be current thread");
if (!is_interp_only_mode()) {
_cur_stack_depth = UNKNOWN_STACK_DEPTH;
}
if (_cur_stack_depth != UNKNOWN_STACK_DEPTH) {
++_cur_stack_depth;
}
}
void JvmtiThreadState::decr_cur_stack_depth() {
guarantee(JavaThread::current() == get_thread(), "must be current thread");
if (!is_interp_only_mode()) {
_cur_stack_depth = UNKNOWN_STACK_DEPTH;
}
if (_cur_stack_depth != UNKNOWN_STACK_DEPTH) {
--_cur_stack_depth;
assert(_cur_stack_depth >= 0, "incr/decr_cur_stack_depth mismatch");
}
}
int JvmtiThreadState::cur_stack_depth() {
guarantee(SafepointSynchronize::is_at_safepoint() ||
(JavaThread *)Thread::current() == get_thread(),
"must be current thread or at safepoint");
if (!is_interp_only_mode() || _cur_stack_depth == UNKNOWN_STACK_DEPTH) {
_cur_stack_depth = count_frames();
} else {
// heavy weight assert
assert(_cur_stack_depth == count_frames(),
"cur_stack_depth out of sync");
}
return _cur_stack_depth;
}
bool JvmtiThreadState::may_be_walked() {
return (get_thread()->is_being_ext_suspended() || (JavaThread::current() == get_thread()));
}
void JvmtiThreadState::process_pending_step_for_popframe() {
// We are single stepping as the last part of the PopFrame() dance
// so we have some house keeping to do.
JavaThread *thr = get_thread();
if (thr->popframe_condition() != JavaThread::popframe_inactive) {
// If the popframe_condition field is not popframe_inactive, then
// we missed all of the popframe_field cleanup points:
//
// - unpack_frames() was not called (nothing to deopt)
// - remove_activation_preserving_args_entry() was not called
// (did not get suspended in a call_vm() family call and did
// not complete a call_vm() family call on the way here)
thr->clear_popframe_condition();
}
// clearing the flag indicates we are done with the PopFrame() dance
clr_pending_step_for_popframe();
// If exception was thrown in this frame, need to reset jvmti thread state.
// Single stepping may not get enabled correctly by the agent since
// exception state is passed in MethodExit event which may be sent at some
// time in the future. JDWP agent ignores MethodExit events if caused by
// an exception.
//
if (is_exception_detected()) {
clear_exception_state();
}
// If step is pending for popframe then it may not be
// a repeat step. The new_bci and method_id is same as current_bci
// and current method_id after pop and step for recursive calls.
// Force the step by clearing the last location.
JvmtiEnvThreadStateIterator it(this);
for (JvmtiEnvThreadState* ets = it.first(); ets != NULL; ets = it.next(ets)) {
ets->clear_current_location();
}
}
// Class: JvmtiThreadState
// Function: update_for_pop_top_frame
// Description:
// This function removes any frame pop notification request for
// the top frame and invalidates both the current stack depth and
// all cached frameIDs.
//
// Called by: PopFrame
//
void JvmtiThreadState::update_for_pop_top_frame() {
if (is_interp_only_mode()) {
// remove any frame pop notification request for the top frame
// in any environment
int popframe_number = cur_stack_depth();
{
JvmtiEnvThreadStateIterator it(this);
for (JvmtiEnvThreadState* ets = it.first(); ets != NULL; ets = it.next(ets)) {
if (ets->is_frame_pop(popframe_number)) {
ets->clear_frame_pop(popframe_number);
}
}
}
// force stack depth to be recalculated
invalidate_cur_stack_depth();
} else {
assert(!is_enabled(JVMTI_EVENT_FRAME_POP), "Must have no framepops set");
}
}
void JvmtiThreadState::process_pending_step_for_earlyret() {
// We are single stepping as the last part of the ForceEarlyReturn
// dance so we have some house keeping to do.
if (is_earlyret_pending()) {
// If the earlyret_state field is not earlyret_inactive, then
// we missed all of the earlyret_field cleanup points:
//
// - remove_activation() was not called
// (did not get suspended in a call_vm() family call and did
// not complete a call_vm() family call on the way here)
//
// One legitimate way for us to miss all the cleanup points is
// if we got here right after handling a compiled return. If that
// is the case, then we consider our return from compiled code to
// complete the ForceEarlyReturn request and we clear the condition.
clr_earlyret_pending();
set_earlyret_oop(NULL);
clr_earlyret_value();
}
// clearing the flag indicates we are done with
// the ForceEarlyReturn() dance
clr_pending_step_for_earlyret();
// If exception was thrown in this frame, need to reset jvmti thread state.
// Single stepping may not get enabled correctly by the agent since
// exception state is passed in MethodExit event which may be sent at some
// time in the future. JDWP agent ignores MethodExit events if caused by
// an exception.
//
if (is_exception_detected()) {
clear_exception_state();
}
// If step is pending for earlyret then it may not be a repeat step.
// The new_bci and method_id is same as current_bci and current
// method_id after earlyret and step for recursive calls.
// Force the step by clearing the last location.
JvmtiEnvThreadStateIterator it(this);
for (JvmtiEnvThreadState* ets = it.first(); ets != NULL; ets = it.next(ets)) {
ets->clear_current_location();
}
}
void JvmtiThreadState::oops_do(OopClosure* f) {
f->do_oop((oop*) &_earlyret_oop);
}