Java example source code file (jvmtiImpl.cpp)
The jvmtiImpl.cpp Java example source code
/*
* Copyright (c) 2003, 2013, 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 "classfile/systemDictionary.hpp"
#include "interpreter/interpreter.hpp"
#include "jvmtifiles/jvmtiEnv.hpp"
#include "memory/resourceArea.hpp"
#include "oops/instanceKlass.hpp"
#include "prims/jvmtiAgentThread.hpp"
#include "prims/jvmtiEventController.inline.hpp"
#include "prims/jvmtiImpl.hpp"
#include "prims/jvmtiRedefineClasses.hpp"
#include "runtime/atomic.hpp"
#include "runtime/deoptimization.hpp"
#include "runtime/handles.hpp"
#include "runtime/handles.inline.hpp"
#include "runtime/interfaceSupport.hpp"
#include "runtime/javaCalls.hpp"
#include "runtime/os.hpp"
#include "runtime/serviceThread.hpp"
#include "runtime/signature.hpp"
#include "runtime/thread.inline.hpp"
#include "runtime/vframe.hpp"
#include "runtime/vframe_hp.hpp"
#include "runtime/vm_operations.hpp"
#include "utilities/exceptions.hpp"
//
// class JvmtiAgentThread
//
// JavaThread used to wrap a thread started by an agent
// using the JVMTI method RunAgentThread.
//
JvmtiAgentThread::JvmtiAgentThread(JvmtiEnv* env, jvmtiStartFunction start_fn, const void *start_arg)
: JavaThread(start_function_wrapper) {
_env = env;
_start_fn = start_fn;
_start_arg = start_arg;
}
void
JvmtiAgentThread::start_function_wrapper(JavaThread *thread, TRAPS) {
// It is expected that any Agent threads will be created as
// Java Threads. If this is the case, notification of the creation
// of the thread is given in JavaThread::thread_main().
assert(thread->is_Java_thread(), "debugger thread should be a Java Thread");
assert(thread == JavaThread::current(), "sanity check");
JvmtiAgentThread *dthread = (JvmtiAgentThread *)thread;
dthread->call_start_function();
}
void
JvmtiAgentThread::call_start_function() {
ThreadToNativeFromVM transition(this);
_start_fn(_env->jvmti_external(), jni_environment(), (void*)_start_arg);
}
//
// class GrowableCache - private methods
//
void GrowableCache::recache() {
int len = _elements->length();
FREE_C_HEAP_ARRAY(address, _cache, mtInternal);
_cache = NEW_C_HEAP_ARRAY(address,len+1, mtInternal);
for (int i=0; i<len; i++) {
_cache[i] = _elements->at(i)->getCacheValue();
//
// The cache entry has gone bad. Without a valid frame pointer
// value, the entry is useless so we simply delete it in product
// mode. The call to remove() will rebuild the cache again
// without the bad entry.
//
if (_cache[i] == NULL) {
assert(false, "cannot recache NULL elements");
remove(i);
return;
}
}
_cache[len] = NULL;
_listener_fun(_this_obj,_cache);
}
bool GrowableCache::equals(void* v, GrowableElement *e2) {
GrowableElement *e1 = (GrowableElement *) v;
assert(e1 != NULL, "e1 != NULL");
assert(e2 != NULL, "e2 != NULL");
return e1->equals(e2);
}
//
// class GrowableCache - public methods
//
GrowableCache::GrowableCache() {
_this_obj = NULL;
_listener_fun = NULL;
_elements = NULL;
_cache = NULL;
}
GrowableCache::~GrowableCache() {
clear();
delete _elements;
FREE_C_HEAP_ARRAY(address, _cache, mtInternal);
}
void GrowableCache::initialize(void *this_obj, void listener_fun(void *, address*) ) {
_this_obj = this_obj;
_listener_fun = listener_fun;
_elements = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<GrowableElement*>(5,true);
recache();
}
// number of elements in the collection
int GrowableCache::length() {
return _elements->length();
}
// get the value of the index element in the collection
GrowableElement* GrowableCache::at(int index) {
GrowableElement *e = (GrowableElement *) _elements->at(index);
assert(e != NULL, "e != NULL");
return e;
}
int GrowableCache::find(GrowableElement* e) {
return _elements->find(e, GrowableCache::equals);
}
// append a copy of the element to the end of the collection
void GrowableCache::append(GrowableElement* e) {
GrowableElement *new_e = e->clone();
_elements->append(new_e);
recache();
}
// insert a copy of the element using lessthan()
void GrowableCache::insert(GrowableElement* e) {
GrowableElement *new_e = e->clone();
_elements->append(new_e);
int n = length()-2;
for (int i=n; i>=0; i--) {
GrowableElement *e1 = _elements->at(i);
GrowableElement *e2 = _elements->at(i+1);
if (e2->lessThan(e1)) {
_elements->at_put(i+1, e1);
_elements->at_put(i, e2);
}
}
recache();
}
// remove the element at index
void GrowableCache::remove (int index) {
GrowableElement *e = _elements->at(index);
assert(e != NULL, "e != NULL");
_elements->remove(e);
delete e;
recache();
}
// clear out all elements, release all heap space and
// let our listener know that things have changed.
void GrowableCache::clear() {
int len = _elements->length();
for (int i=0; i<len; i++) {
delete _elements->at(i);
}
_elements->clear();
recache();
}
void GrowableCache::oops_do(OopClosure* f) {
int len = _elements->length();
for (int i=0; i<len; i++) {
GrowableElement *e = _elements->at(i);
e->oops_do(f);
}
}
void GrowableCache::metadata_do(void f(Metadata*)) {
int len = _elements->length();
for (int i=0; i<len; i++) {
GrowableElement *e = _elements->at(i);
e->metadata_do(f);
}
}
void GrowableCache::gc_epilogue() {
int len = _elements->length();
for (int i=0; i<len; i++) {
_cache[i] = _elements->at(i)->getCacheValue();
}
}
//
// class JvmtiBreakpoint
//
JvmtiBreakpoint::JvmtiBreakpoint() {
_method = NULL;
_bci = 0;
_class_holder = NULL;
}
JvmtiBreakpoint::JvmtiBreakpoint(Method* m_method, jlocation location) {
_method = m_method;
_class_holder = _method->method_holder()->klass_holder();
#ifdef CHECK_UNHANDLED_OOPS
// _class_holder can't be wrapped in a Handle, because JvmtiBreakpoints are
// sometimes allocated on the heap.
//
// The code handling JvmtiBreakpoints allocated on the stack can't be
// interrupted by a GC until _class_holder is reachable by the GC via the
// oops_do method.
Thread::current()->allow_unhandled_oop(&_class_holder);
#endif // CHECK_UNHANDLED_OOPS
assert(_method != NULL, "_method != NULL");
_bci = (int) location;
assert(_bci >= 0, "_bci >= 0");
}
void JvmtiBreakpoint::copy(JvmtiBreakpoint& bp) {
_method = bp._method;
_bci = bp._bci;
_class_holder = bp._class_holder;
}
bool JvmtiBreakpoint::lessThan(JvmtiBreakpoint& bp) {
Unimplemented();
return false;
}
bool JvmtiBreakpoint::equals(JvmtiBreakpoint& bp) {
return _method == bp._method
&& _bci == bp._bci;
}
bool JvmtiBreakpoint::is_valid() {
// class loader can be NULL
return _method != NULL &&
_bci >= 0;
}
address JvmtiBreakpoint::getBcp() {
return _method->bcp_from(_bci);
}
void JvmtiBreakpoint::each_method_version_do(method_action meth_act) {
((Method*)_method->*meth_act)(_bci);
// add/remove breakpoint to/from versions of the method that
// are EMCP. Directly or transitively obsolete methods are
// not saved in the PreviousVersionNodes.
Thread *thread = Thread::current();
instanceKlassHandle ikh = instanceKlassHandle(thread, _method->method_holder());
Symbol* m_name = _method->name();
Symbol* m_signature = _method->signature();
// search previous versions if they exist
PreviousVersionWalker pvw(thread, (InstanceKlass *)ikh());
for (PreviousVersionNode * pv_node = pvw.next_previous_version();
pv_node != NULL; pv_node = pvw.next_previous_version()) {
GrowableArray<Method*>* methods = pv_node->prev_EMCP_methods();
if (methods == NULL) {
// We have run into a PreviousVersion generation where
// all methods were made obsolete during that generation's
// RedefineClasses() operation. At the time of that
// operation, all EMCP methods were flushed so we don't
// have to go back any further.
//
// A NULL methods array is different than an empty methods
// array. We cannot infer any optimizations about older
// generations from an empty methods array for the current
// generation.
break;
}
for (int i = methods->length() - 1; i >= 0; i--) {
Method* method = methods->at(i);
// obsolete methods that are running are not deleted from
// previous version array, but they are skipped here.
if (!method->is_obsolete() &&
method->name() == m_name &&
method->signature() == m_signature) {
RC_TRACE(0x00000800, ("%sing breakpoint in %s(%s)",
meth_act == &Method::set_breakpoint ? "sett" : "clear",
method->name()->as_C_string(),
method->signature()->as_C_string()));
(method->*meth_act)(_bci);
break;
}
}
}
}
void JvmtiBreakpoint::set() {
each_method_version_do(&Method::set_breakpoint);
}
void JvmtiBreakpoint::clear() {
each_method_version_do(&Method::clear_breakpoint);
}
void JvmtiBreakpoint::print() {
#ifndef PRODUCT
const char *class_name = (_method == NULL) ? "NULL" : _method->klass_name()->as_C_string();
const char *method_name = (_method == NULL) ? "NULL" : _method->name()->as_C_string();
tty->print("Breakpoint(%s,%s,%d,%p)",class_name, method_name, _bci, getBcp());
#endif
}
//
// class VM_ChangeBreakpoints
//
// Modify the Breakpoints data structure at a safepoint
//
void VM_ChangeBreakpoints::doit() {
switch (_operation) {
case SET_BREAKPOINT:
_breakpoints->set_at_safepoint(*_bp);
break;
case CLEAR_BREAKPOINT:
_breakpoints->clear_at_safepoint(*_bp);
break;
default:
assert(false, "Unknown operation");
}
}
void VM_ChangeBreakpoints::oops_do(OopClosure* f) {
// The JvmtiBreakpoints in _breakpoints will be visited via
// JvmtiExport::oops_do.
if (_bp != NULL) {
_bp->oops_do(f);
}
}
void VM_ChangeBreakpoints::metadata_do(void f(Metadata*)) {
// Walk metadata in breakpoints to keep from being deallocated with RedefineClasses
if (_bp != NULL) {
_bp->metadata_do(f);
}
}
//
// class JvmtiBreakpoints
//
// a JVMTI internal collection of JvmtiBreakpoint
//
JvmtiBreakpoints::JvmtiBreakpoints(void listener_fun(void *,address *)) {
_bps.initialize(this,listener_fun);
}
JvmtiBreakpoints:: ~JvmtiBreakpoints() {}
void JvmtiBreakpoints::oops_do(OopClosure* f) {
_bps.oops_do(f);
}
void JvmtiBreakpoints::metadata_do(void f(Metadata*)) {
_bps.metadata_do(f);
}
void JvmtiBreakpoints::gc_epilogue() {
_bps.gc_epilogue();
}
void JvmtiBreakpoints::print() {
#ifndef PRODUCT
ResourceMark rm;
int n = _bps.length();
for (int i=0; i<n; i++) {
JvmtiBreakpoint& bp = _bps.at(i);
tty->print("%d: ", i);
bp.print();
tty->print_cr("");
}
#endif
}
void JvmtiBreakpoints::set_at_safepoint(JvmtiBreakpoint& bp) {
assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
int i = _bps.find(bp);
if (i == -1) {
_bps.append(bp);
bp.set();
}
}
void JvmtiBreakpoints::clear_at_safepoint(JvmtiBreakpoint& bp) {
assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
int i = _bps.find(bp);
if (i != -1) {
_bps.remove(i);
bp.clear();
}
}
int JvmtiBreakpoints::length() { return _bps.length(); }
int JvmtiBreakpoints::set(JvmtiBreakpoint& bp) {
if ( _bps.find(bp) != -1) {
return JVMTI_ERROR_DUPLICATE;
}
VM_ChangeBreakpoints set_breakpoint(VM_ChangeBreakpoints::SET_BREAKPOINT, &bp);
VMThread::execute(&set_breakpoint);
return JVMTI_ERROR_NONE;
}
int JvmtiBreakpoints::clear(JvmtiBreakpoint& bp) {
if ( _bps.find(bp) == -1) {
return JVMTI_ERROR_NOT_FOUND;
}
VM_ChangeBreakpoints clear_breakpoint(VM_ChangeBreakpoints::CLEAR_BREAKPOINT, &bp);
VMThread::execute(&clear_breakpoint);
return JVMTI_ERROR_NONE;
}
void JvmtiBreakpoints::clearall_in_class_at_safepoint(Klass* klass) {
bool changed = true;
// We are going to run thru the list of bkpts
// and delete some. This deletion probably alters
// the list in some implementation defined way such
// that when we delete entry i, the next entry might
// no longer be at i+1. To be safe, each time we delete
// an entry, we'll just start again from the beginning.
// We'll stop when we make a pass thru the whole list without
// deleting anything.
while (changed) {
int len = _bps.length();
changed = false;
for (int i = 0; i < len; i++) {
JvmtiBreakpoint& bp = _bps.at(i);
if (bp.method()->method_holder() == klass) {
bp.clear();
_bps.remove(i);
// This changed 'i' so we have to start over.
changed = true;
break;
}
}
}
}
//
// class JvmtiCurrentBreakpoints
//
JvmtiBreakpoints *JvmtiCurrentBreakpoints::_jvmti_breakpoints = NULL;
address * JvmtiCurrentBreakpoints::_breakpoint_list = NULL;
JvmtiBreakpoints& JvmtiCurrentBreakpoints::get_jvmti_breakpoints() {
if (_jvmti_breakpoints != NULL) return (*_jvmti_breakpoints);
_jvmti_breakpoints = new JvmtiBreakpoints(listener_fun);
assert(_jvmti_breakpoints != NULL, "_jvmti_breakpoints != NULL");
return (*_jvmti_breakpoints);
}
void JvmtiCurrentBreakpoints::listener_fun(void *this_obj, address *cache) {
JvmtiBreakpoints *this_jvmti = (JvmtiBreakpoints *) this_obj;
assert(this_jvmti != NULL, "this_jvmti != NULL");
debug_only(int n = this_jvmti->length(););
assert(cache[n] == NULL, "cache must be NULL terminated");
set_breakpoint_list(cache);
}
void JvmtiCurrentBreakpoints::oops_do(OopClosure* f) {
if (_jvmti_breakpoints != NULL) {
_jvmti_breakpoints->oops_do(f);
}
}
void JvmtiCurrentBreakpoints::metadata_do(void f(Metadata*)) {
if (_jvmti_breakpoints != NULL) {
_jvmti_breakpoints->metadata_do(f);
}
}
void JvmtiCurrentBreakpoints::gc_epilogue() {
if (_jvmti_breakpoints != NULL) {
_jvmti_breakpoints->gc_epilogue();
}
}
///////////////////////////////////////////////////////////////
//
// class VM_GetOrSetLocal
//
// Constructor for non-object getter
VM_GetOrSetLocal::VM_GetOrSetLocal(JavaThread* thread, jint depth, int index, BasicType type)
: _thread(thread)
, _calling_thread(NULL)
, _depth(depth)
, _index(index)
, _type(type)
, _set(false)
, _jvf(NULL)
, _result(JVMTI_ERROR_NONE)
{
}
// Constructor for object or non-object setter
VM_GetOrSetLocal::VM_GetOrSetLocal(JavaThread* thread, jint depth, int index, BasicType type, jvalue value)
: _thread(thread)
, _calling_thread(NULL)
, _depth(depth)
, _index(index)
, _type(type)
, _value(value)
, _set(true)
, _jvf(NULL)
, _result(JVMTI_ERROR_NONE)
{
}
// Constructor for object getter
VM_GetOrSetLocal::VM_GetOrSetLocal(JavaThread* thread, JavaThread* calling_thread, jint depth, int index)
: _thread(thread)
, _calling_thread(calling_thread)
, _depth(depth)
, _index(index)
, _type(T_OBJECT)
, _set(false)
, _jvf(NULL)
, _result(JVMTI_ERROR_NONE)
{
}
vframe *VM_GetOrSetLocal::get_vframe() {
if (!_thread->has_last_Java_frame()) {
return NULL;
}
RegisterMap reg_map(_thread);
vframe *vf = _thread->last_java_vframe(®_map);
int d = 0;
while ((vf != NULL) && (d < _depth)) {
vf = vf->java_sender();
d++;
}
return vf;
}
javaVFrame *VM_GetOrSetLocal::get_java_vframe() {
vframe* vf = get_vframe();
if (vf == NULL) {
_result = JVMTI_ERROR_NO_MORE_FRAMES;
return NULL;
}
javaVFrame *jvf = (javaVFrame*)vf;
if (!vf->is_java_frame()) {
_result = JVMTI_ERROR_OPAQUE_FRAME;
return NULL;
}
return jvf;
}
// Check that the klass is assignable to a type with the given signature.
// Another solution could be to use the function Klass::is_subtype_of(type).
// But the type class can be forced to load/initialize eagerly in such a case.
// This may cause unexpected consequences like CFLH or class-init JVMTI events.
// It is better to avoid such a behavior.
bool VM_GetOrSetLocal::is_assignable(const char* ty_sign, Klass* klass, Thread* thread) {
assert(ty_sign != NULL, "type signature must not be NULL");
assert(thread != NULL, "thread must not be NULL");
assert(klass != NULL, "klass must not be NULL");
int len = (int) strlen(ty_sign);
if (ty_sign[0] == 'L' && ty_sign[len-1] == ';') { // Need pure class/interface name
ty_sign++;
len -= 2;
}
TempNewSymbol ty_sym = SymbolTable::new_symbol(ty_sign, len, thread);
if (klass->name() == ty_sym) {
return true;
}
// Compare primary supers
int super_depth = klass->super_depth();
int idx;
for (idx = 0; idx < super_depth; idx++) {
if (klass->primary_super_of_depth(idx)->name() == ty_sym) {
return true;
}
}
// Compare secondary supers
Array<Klass*>* sec_supers = klass->secondary_supers();
for (idx = 0; idx < sec_supers->length(); idx++) {
if (((Klass*) sec_supers->at(idx))->name() == ty_sym) {
return true;
}
}
return false;
}
// Checks error conditions:
// JVMTI_ERROR_INVALID_SLOT
// JVMTI_ERROR_TYPE_MISMATCH
// Returns: 'true' - everything is Ok, 'false' - error code
bool VM_GetOrSetLocal::check_slot_type(javaVFrame* jvf) {
Method* method_oop = jvf->method();
if (!method_oop->has_localvariable_table()) {
// Just to check index boundaries
jint extra_slot = (_type == T_LONG || _type == T_DOUBLE) ? 1 : 0;
if (_index < 0 || _index + extra_slot >= method_oop->max_locals()) {
_result = JVMTI_ERROR_INVALID_SLOT;
return false;
}
return true;
}
jint num_entries = method_oop->localvariable_table_length();
if (num_entries == 0) {
_result = JVMTI_ERROR_INVALID_SLOT;
return false; // There are no slots
}
int signature_idx = -1;
int vf_bci = jvf->bci();
LocalVariableTableElement* table = method_oop->localvariable_table_start();
for (int i = 0; i < num_entries; i++) {
int start_bci = table[i].start_bci;
int end_bci = start_bci + table[i].length;
// Here we assume that locations of LVT entries
// with the same slot number cannot be overlapped
if (_index == (jint) table[i].slot && start_bci <= vf_bci && vf_bci <= end_bci) {
signature_idx = (int) table[i].descriptor_cp_index;
break;
}
}
if (signature_idx == -1) {
_result = JVMTI_ERROR_INVALID_SLOT;
return false; // Incorrect slot index
}
Symbol* sign_sym = method_oop->constants()->symbol_at(signature_idx);
const char* signature = (const char *) sign_sym->as_utf8();
BasicType slot_type = char2type(signature[0]);
switch (slot_type) {
case T_BYTE:
case T_SHORT:
case T_CHAR:
case T_BOOLEAN:
slot_type = T_INT;
break;
case T_ARRAY:
slot_type = T_OBJECT;
break;
};
if (_type != slot_type) {
_result = JVMTI_ERROR_TYPE_MISMATCH;
return false;
}
jobject jobj = _value.l;
if (_set && slot_type == T_OBJECT && jobj != NULL) { // NULL reference is allowed
// Check that the jobject class matches the return type signature.
JavaThread* cur_thread = JavaThread::current();
HandleMark hm(cur_thread);
Handle obj = Handle(cur_thread, JNIHandles::resolve_external_guard(jobj));
NULL_CHECK(obj, (_result = JVMTI_ERROR_INVALID_OBJECT, false));
KlassHandle ob_kh = KlassHandle(cur_thread, obj->klass());
NULL_CHECK(ob_kh, (_result = JVMTI_ERROR_INVALID_OBJECT, false));
if (!is_assignable(signature, ob_kh(), cur_thread)) {
_result = JVMTI_ERROR_TYPE_MISMATCH;
return false;
}
}
return true;
}
static bool can_be_deoptimized(vframe* vf) {
return (vf->is_compiled_frame() && vf->fr().can_be_deoptimized());
}
bool VM_GetOrSetLocal::doit_prologue() {
_jvf = get_java_vframe();
NULL_CHECK(_jvf, false);
if (_jvf->method()->is_native()) {
if (getting_receiver() && !_jvf->method()->is_static()) {
return true;
} else {
_result = JVMTI_ERROR_OPAQUE_FRAME;
return false;
}
}
if (!check_slot_type(_jvf)) {
return false;
}
return true;
}
void VM_GetOrSetLocal::doit() {
if (_set) {
// Force deoptimization of frame if compiled because it's
// possible the compiler emitted some locals as constant values,
// meaning they are not mutable.
if (can_be_deoptimized(_jvf)) {
// Schedule deoptimization so that eventually the local
// update will be written to an interpreter frame.
Deoptimization::deoptimize_frame(_jvf->thread(), _jvf->fr().id());
// Now store a new value for the local which will be applied
// once deoptimization occurs. Note however that while this
// write is deferred until deoptimization actually happens
// can vframe created after this point will have its locals
// reflecting this update so as far as anyone can see the
// write has already taken place.
// If we are updating an oop then get the oop from the handle
// since the handle will be long gone by the time the deopt
// happens. The oop stored in the deferred local will be
// gc'd on its own.
if (_type == T_OBJECT) {
_value.l = (jobject) (JNIHandles::resolve_external_guard(_value.l));
}
// Re-read the vframe so we can see that it is deoptimized
// [ Only need because of assert in update_local() ]
_jvf = get_java_vframe();
((compiledVFrame*)_jvf)->update_local(_type, _index, _value);
return;
}
StackValueCollection *locals = _jvf->locals();
HandleMark hm;
switch (_type) {
case T_INT: locals->set_int_at (_index, _value.i); break;
case T_LONG: locals->set_long_at (_index, _value.j); break;
case T_FLOAT: locals->set_float_at (_index, _value.f); break;
case T_DOUBLE: locals->set_double_at(_index, _value.d); break;
case T_OBJECT: {
Handle ob_h(JNIHandles::resolve_external_guard(_value.l));
locals->set_obj_at (_index, ob_h);
break;
}
default: ShouldNotReachHere();
}
_jvf->set_locals(locals);
} else {
if (_jvf->method()->is_native() && _jvf->is_compiled_frame()) {
assert(getting_receiver(), "Can only get here when getting receiver");
oop receiver = _jvf->fr().get_native_receiver();
_value.l = JNIHandles::make_local(_calling_thread, receiver);
} else {
StackValueCollection *locals = _jvf->locals();
if (locals->at(_index)->type() == T_CONFLICT) {
memset(&_value, 0, sizeof(_value));
_value.l = NULL;
return;
}
switch (_type) {
case T_INT: _value.i = locals->int_at (_index); break;
case T_LONG: _value.j = locals->long_at (_index); break;
case T_FLOAT: _value.f = locals->float_at (_index); break;
case T_DOUBLE: _value.d = locals->double_at(_index); break;
case T_OBJECT: {
// Wrap the oop to be returned in a local JNI handle since
// oops_do() no longer applies after doit() is finished.
oop obj = locals->obj_at(_index)();
_value.l = JNIHandles::make_local(_calling_thread, obj);
break;
}
default: ShouldNotReachHere();
}
}
}
}
bool VM_GetOrSetLocal::allow_nested_vm_operations() const {
return true; // May need to deoptimize
}
VM_GetReceiver::VM_GetReceiver(
JavaThread* thread, JavaThread* caller_thread, jint depth)
: VM_GetOrSetLocal(thread, caller_thread, depth, 0) {}
/////////////////////////////////////////////////////////////////////////////////////////
//
// class JvmtiSuspendControl - see comments in jvmtiImpl.hpp
//
bool JvmtiSuspendControl::suspend(JavaThread *java_thread) {
// external suspend should have caught suspending a thread twice
// Immediate suspension required for JPDA back-end so JVMTI agent threads do
// not deadlock due to later suspension on transitions while holding
// raw monitors. Passing true causes the immediate suspension.
// java_suspend() will catch threads in the process of exiting
// and will ignore them.
java_thread->java_suspend();
// It would be nice to have the following assertion in all the time,
// but it is possible for a racing resume request to have resumed
// this thread right after we suspended it. Temporarily enable this
// assertion if you are chasing a different kind of bug.
//
// assert(java_lang_Thread::thread(java_thread->threadObj()) == NULL ||
// java_thread->is_being_ext_suspended(), "thread is not suspended");
if (java_lang_Thread::thread(java_thread->threadObj()) == NULL) {
// check again because we can get delayed in java_suspend():
// the thread is in process of exiting.
return false;
}
return true;
}
bool JvmtiSuspendControl::resume(JavaThread *java_thread) {
// external suspend should have caught resuming a thread twice
assert(java_thread->is_being_ext_suspended(), "thread should be suspended");
// resume thread
{
// must always grab Threads_lock, see JVM_SuspendThread
MutexLocker ml(Threads_lock);
java_thread->java_resume();
}
return true;
}
void JvmtiSuspendControl::print() {
#ifndef PRODUCT
MutexLocker mu(Threads_lock);
ResourceMark rm;
tty->print("Suspended Threads: [");
for (JavaThread *thread = Threads::first(); thread != NULL; thread = thread->next()) {
#ifdef JVMTI_TRACE
const char *name = JvmtiTrace::safe_get_thread_name(thread);
#else
const char *name = "";
#endif /*JVMTI_TRACE */
tty->print("%s(%c ", name, thread->is_being_ext_suspended() ? 'S' : '_');
if (!thread->has_last_Java_frame()) {
tty->print("no stack");
}
tty->print(") ");
}
tty->print_cr("]");
#endif
}
JvmtiDeferredEvent JvmtiDeferredEvent::compiled_method_load_event(
nmethod* nm) {
JvmtiDeferredEvent event = JvmtiDeferredEvent(TYPE_COMPILED_METHOD_LOAD);
event._event_data.compiled_method_load = nm;
// Keep the nmethod alive until the ServiceThread can process
// this deferred event.
nmethodLocker::lock_nmethod(nm);
return event;
}
JvmtiDeferredEvent JvmtiDeferredEvent::compiled_method_unload_event(
nmethod* nm, jmethodID id, const void* code) {
JvmtiDeferredEvent event = JvmtiDeferredEvent(TYPE_COMPILED_METHOD_UNLOAD);
event._event_data.compiled_method_unload.nm = nm;
event._event_data.compiled_method_unload.method_id = id;
event._event_data.compiled_method_unload.code_begin = code;
// Keep the nmethod alive until the ServiceThread can process
// this deferred event. This will keep the memory for the
// generated code from being reused too early. We pass
// zombie_ok == true here so that our nmethod that was just
// made into a zombie can be locked.
nmethodLocker::lock_nmethod(nm, true /* zombie_ok */);
return event;
}
JvmtiDeferredEvent JvmtiDeferredEvent::dynamic_code_generated_event(
const char* name, const void* code_begin, const void* code_end) {
JvmtiDeferredEvent event = JvmtiDeferredEvent(TYPE_DYNAMIC_CODE_GENERATED);
// Need to make a copy of the name since we don't know how long
// the event poster will keep it around after we enqueue the
// deferred event and return. strdup() failure is handled in
// the post() routine below.
event._event_data.dynamic_code_generated.name = os::strdup(name);
event._event_data.dynamic_code_generated.code_begin = code_begin;
event._event_data.dynamic_code_generated.code_end = code_end;
return event;
}
void JvmtiDeferredEvent::post() {
assert(ServiceThread::is_service_thread(Thread::current()),
"Service thread must post enqueued events");
switch(_type) {
case TYPE_COMPILED_METHOD_LOAD: {
nmethod* nm = _event_data.compiled_method_load;
JvmtiExport::post_compiled_method_load(nm);
// done with the deferred event so unlock the nmethod
nmethodLocker::unlock_nmethod(nm);
break;
}
case TYPE_COMPILED_METHOD_UNLOAD: {
nmethod* nm = _event_data.compiled_method_unload.nm;
JvmtiExport::post_compiled_method_unload(
_event_data.compiled_method_unload.method_id,
_event_data.compiled_method_unload.code_begin);
// done with the deferred event so unlock the nmethod
nmethodLocker::unlock_nmethod(nm);
break;
}
case TYPE_DYNAMIC_CODE_GENERATED: {
JvmtiExport::post_dynamic_code_generated_internal(
// if strdup failed give the event a default name
(_event_data.dynamic_code_generated.name == NULL)
? "unknown_code" : _event_data.dynamic_code_generated.name,
_event_data.dynamic_code_generated.code_begin,
_event_data.dynamic_code_generated.code_end);
if (_event_data.dynamic_code_generated.name != NULL) {
// release our copy
os::free((void *)_event_data.dynamic_code_generated.name);
}
break;
}
default:
ShouldNotReachHere();
}
}
JvmtiDeferredEventQueue::QueueNode* JvmtiDeferredEventQueue::_queue_tail = NULL;
JvmtiDeferredEventQueue::QueueNode* JvmtiDeferredEventQueue::_queue_head = NULL;
volatile JvmtiDeferredEventQueue::QueueNode*
JvmtiDeferredEventQueue::_pending_list = NULL;
bool JvmtiDeferredEventQueue::has_events() {
assert(Service_lock->owned_by_self(), "Must own Service_lock");
return _queue_head != NULL || _pending_list != NULL;
}
void JvmtiDeferredEventQueue::enqueue(const JvmtiDeferredEvent& event) {
assert(Service_lock->owned_by_self(), "Must own Service_lock");
process_pending_events();
// Events get added to the end of the queue (and are pulled off the front).
QueueNode* node = new QueueNode(event);
if (_queue_tail == NULL) {
_queue_tail = _queue_head = node;
} else {
assert(_queue_tail->next() == NULL, "Must be the last element in the list");
_queue_tail->set_next(node);
_queue_tail = node;
}
Service_lock->notify_all();
assert((_queue_head == NULL) == (_queue_tail == NULL),
"Inconsistent queue markers");
}
JvmtiDeferredEvent JvmtiDeferredEventQueue::dequeue() {
assert(Service_lock->owned_by_self(), "Must own Service_lock");
process_pending_events();
assert(_queue_head != NULL, "Nothing to dequeue");
if (_queue_head == NULL) {
// Just in case this happens in product; it shouldn't but let's not crash
return JvmtiDeferredEvent();
}
QueueNode* node = _queue_head;
_queue_head = _queue_head->next();
if (_queue_head == NULL) {
_queue_tail = NULL;
}
assert((_queue_head == NULL) == (_queue_tail == NULL),
"Inconsistent queue markers");
JvmtiDeferredEvent event = node->event();
delete node;
return event;
}
void JvmtiDeferredEventQueue::add_pending_event(
const JvmtiDeferredEvent& event) {
QueueNode* node = new QueueNode(event);
bool success = false;
QueueNode* prev_value = (QueueNode*)_pending_list;
do {
node->set_next(prev_value);
prev_value = (QueueNode*)Atomic::cmpxchg_ptr(
(void*)node, (volatile void*)&_pending_list, (void*)node->next());
} while (prev_value != node->next());
}
// This method transfers any events that were added by someone NOT holding
// the lock into the mainline queue.
void JvmtiDeferredEventQueue::process_pending_events() {
assert(Service_lock->owned_by_self(), "Must own Service_lock");
if (_pending_list != NULL) {
QueueNode* head =
(QueueNode*)Atomic::xchg_ptr(NULL, (volatile void*)&_pending_list);
assert((_queue_head == NULL) == (_queue_tail == NULL),
"Inconsistent queue markers");
if (head != NULL) {
// Since we've treated the pending list as a stack (with newer
// events at the beginning), we need to join the bottom of the stack
// with the 'tail' of the queue in order to get the events in the
// right order. We do this by reversing the pending list and appending
// it to the queue.
QueueNode* new_tail = head;
QueueNode* new_head = NULL;
// This reverses the list
QueueNode* prev = new_tail;
QueueNode* node = new_tail->next();
new_tail->set_next(NULL);
while (node != NULL) {
QueueNode* next = node->next();
node->set_next(prev);
prev = node;
node = next;
}
new_head = prev;
// Now append the new list to the queue
if (_queue_tail != NULL) {
_queue_tail->set_next(new_head);
} else { // _queue_head == NULL
_queue_head = new_head;
}
_queue_tail = new_tail;
}
}
}
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