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interfaceSupport.inline.hpp
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interfaceSupport.inline.hpp
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/*
* Copyright (c) 1997, 2021, 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.
*
*/
#ifndef SHARE_RUNTIME_INTERFACESUPPORT_INLINE_HPP
#define SHARE_RUNTIME_INTERFACESUPPORT_INLINE_HPP
#include "gc/shared/gc_globals.hpp"
#include "runtime/handles.inline.hpp"
#include "runtime/mutexLocker.hpp"
#include "runtime/orderAccess.hpp"
#include "runtime/os.hpp"
#include "runtime/safepointMechanism.inline.hpp"
#include "runtime/safepointVerifiers.hpp"
#include "runtime/thread.hpp"
#include "runtime/vmOperations.hpp"
#include "utilities/globalDefinitions.hpp"
#include "utilities/macros.hpp"
#include "utilities/preserveException.hpp"
// Wrapper for all entry points to the virtual machine.
// InterfaceSupport provides functionality used by the VM_LEAF_BASE and
// VM_ENTRY_BASE macros. These macros are used to guard entry points into
// the VM and perform checks upon leave of the VM.
class InterfaceSupport: AllStatic {
# ifdef ASSERT
public:
static unsigned int _scavenge_alot_counter;
static unsigned int _fullgc_alot_counter;
static int _fullgc_alot_invocation;
// Helper methods used to implement +ScavengeALot and +FullGCALot
static void check_gc_alot() { if (ScavengeALot || FullGCALot) gc_alot(); }
static void gc_alot();
static void walk_stack_from(vframe* start_vf);
static void walk_stack();
static void zombieAll();
static void deoptimizeAll();
static void verify_stack();
static void verify_last_frame();
# endif
};
// Basic class for all thread transition classes.
class ThreadStateTransition : public StackObj {
protected:
JavaThread* _thread;
public:
ThreadStateTransition(JavaThread *thread) {
_thread = thread;
assert(thread != NULL, "must be active Java thread");
}
// Change threadstate in a manner, so safepoint can detect changes.
// Time-critical: called on exit from every runtime routine
static inline void transition(JavaThread *thread, JavaThreadState from, JavaThreadState to) {
assert(from != _thread_in_Java, "use transition_from_java");
assert(from != _thread_in_native, "use transition_from_native");
assert((from & 1) == 0 && (to & 1) == 0, "odd numbers are transitions states");
assert(thread->thread_state() == from, "coming from wrong thread state");
// Check NoSafepointVerifier
// This also clears unhandled oops if CheckUnhandledOops is used.
thread->check_possible_safepoint();
// Change to transition state and ensure it is seen by the VM thread.
thread->set_thread_state_fence((JavaThreadState)(from + 1));
SafepointMechanism::process_if_requested(thread);
thread->set_thread_state(to);
}
// Same as above, but assumes from = _thread_in_Java. This is simpler, since we
// never block on entry to the VM. This will break the code, since e.g. preserve arguments
// have not been setup.
static inline void transition_from_java(JavaThread *thread, JavaThreadState to) {
assert(thread->thread_state() == _thread_in_Java, "coming from wrong thread state");
thread->set_thread_state(to);
}
static inline void transition_from_native(JavaThread *thread, JavaThreadState to) {
assert((to & 1) == 0, "odd numbers are transitions states");
assert(thread->thread_state() == _thread_in_native, "coming from wrong thread state");
// Change to transition state and ensure it is seen by the VM thread.
thread->set_thread_state_fence(_thread_in_native_trans);
// We never install asynchronous exceptions when coming (back) in
// to the runtime from native code because the runtime is not set
// up to handle exceptions floating around at arbitrary points.
if (SafepointMechanism::should_process(thread) || thread->is_suspend_after_native()) {
JavaThread::check_safepoint_and_suspend_for_native_trans(thread);
}
thread->set_thread_state(to);
}
protected:
void trans(JavaThreadState from, JavaThreadState to) { transition(_thread, from, to); }
void trans_from_java(JavaThreadState to) { transition_from_java(_thread, to); }
void trans_from_native(JavaThreadState to) { transition_from_native(_thread, to); }
};
class ThreadInVMForHandshake : public ThreadStateTransition {
const JavaThreadState _original_state;
public:
ThreadInVMForHandshake(JavaThread* thread) : ThreadStateTransition(thread),
_original_state(thread->thread_state()) {
if (thread->has_last_Java_frame()) {
thread->frame_anchor()->make_walkable(thread);
}
thread->set_thread_state(_thread_in_vm);
// Threads shouldn't block if they are in the middle of printing, but...
ttyLocker::break_tty_lock_for_safepoint(os::current_thread_id());
}
~ThreadInVMForHandshake() {
assert(_thread->thread_state() == _thread_in_vm, "should only call when leaving VM after handshake");
_thread->set_thread_state(_original_state);
}
};
class ThreadInVMfromJava : public ThreadStateTransition {
bool _check_asyncs;
public:
ThreadInVMfromJava(JavaThread* thread, bool check_asyncs = true) : ThreadStateTransition(thread), _check_asyncs(check_asyncs) {
trans_from_java(_thread_in_vm);
}
~ThreadInVMfromJava() {
if (_thread->stack_overflow_state()->stack_yellow_reserved_zone_disabled()) {
_thread->stack_overflow_state()->enable_stack_yellow_reserved_zone();
}
trans(_thread_in_vm, _thread_in_Java);
// We prevent asynchronous exceptions from being installed on return to Java in situations
// where we can't tolerate them. See bugs: 4324348, 4854693, 4998314, 5040492, 5050705.
if (_thread->has_special_runtime_exit_condition()) _thread->handle_special_runtime_exit_condition(_check_asyncs);
}
};
class ThreadInVMfromUnknown {
JavaThread* _thread;
public:
ThreadInVMfromUnknown() : _thread(NULL) {
Thread* t = Thread::current();
if (t->is_Java_thread()) {
JavaThread* t2 = t->as_Java_thread();
if (t2->thread_state() == _thread_in_native) {
_thread = t2;
ThreadStateTransition::transition_from_native(t2, _thread_in_vm);
// Used to have a HandleMarkCleaner but that is dangerous as
// it could free a handle in our (indirect, nested) caller.
// We expect any handles will be short lived and figure we
// don't need an actual HandleMark.
}
}
}
~ThreadInVMfromUnknown() {
if (_thread) {
ThreadStateTransition::transition(_thread, _thread_in_vm, _thread_in_native);
}
}
};
class ThreadInVMfromNative : public ThreadStateTransition {
ResetNoHandleMark __rnhm;
public:
ThreadInVMfromNative(JavaThread* thread) : ThreadStateTransition(thread) {
trans_from_native(_thread_in_vm);
}
~ThreadInVMfromNative() {
trans(_thread_in_vm, _thread_in_native);
}
};
class ThreadToNativeFromVM : public ThreadStateTransition {
public:
ThreadToNativeFromVM(JavaThread *thread) : ThreadStateTransition(thread) {
// We are leaving the VM at this point and going directly to native code.
// Block, if we are in the middle of a safepoint synchronization.
assert(!thread->owns_locks(), "must release all locks when leaving VM");
thread->frame_anchor()->make_walkable(thread);
trans(_thread_in_vm, _thread_in_native);
// Check for pending. async. exceptions or suspends.
if (_thread->has_special_runtime_exit_condition()) _thread->handle_special_runtime_exit_condition(false);
}
~ThreadToNativeFromVM() {
trans_from_native(_thread_in_vm);
assert(!_thread->is_pending_jni_exception_check(), "Pending JNI Exception Check");
// We don't need to clear_walkable because it will happen automagically when we return to java
}
};
// Parameter in_flight_mutex_addr is only used by class Mutex to avoid certain deadlock
// scenarios while making transitions that might block for a safepoint or handshake.
// It's the address of a pointer to the mutex we are trying to acquire. This will be used to
// access and release said mutex when transitioning back from blocked to vm (destructor) in
// case we need to stop for a safepoint or handshake.
class ThreadBlockInVM : public ThreadStateTransition {
private:
Mutex** _in_flight_mutex_addr;
public:
ThreadBlockInVM(JavaThread* thread, Mutex** in_flight_mutex_addr = NULL)
: ThreadStateTransition(thread), _in_flight_mutex_addr(in_flight_mutex_addr) {
assert(thread->thread_state() == _thread_in_vm, "coming from wrong thread state");
thread->check_possible_safepoint();
// Once we are blocked vm expects stack to be walkable
thread->frame_anchor()->make_walkable(thread);
thread->set_thread_state(_thread_blocked);
}
~ThreadBlockInVM() {
assert(_thread->thread_state() == _thread_blocked, "coming from wrong thread state");
// Change to transition state and ensure it is seen by the VM thread.
_thread->set_thread_state_fence(_thread_blocked_trans);
if (SafepointMechanism::should_process(_thread)) {
if (_in_flight_mutex_addr != NULL) {
release_mutex();
}
SafepointMechanism::process_if_requested(_thread);
}
_thread->set_thread_state(_thread_in_vm);
}
void release_mutex() {
Mutex* in_flight_mutex = *_in_flight_mutex_addr;
if (in_flight_mutex != NULL) {
in_flight_mutex->release_for_safepoint();
*_in_flight_mutex_addr = NULL;
}
}
};
// Debug class instantiated in JRT_ENTRY macro.
// Can be used to verify properties on enter/exit of the VM.
#ifdef ASSERT
class VMEntryWrapper {
public:
VMEntryWrapper();
~VMEntryWrapper();
};
class VMNativeEntryWrapper {
public:
VMNativeEntryWrapper();
~VMNativeEntryWrapper();
};
#endif // ASSERT
// LEAF routines do not lock, GC or throw exceptions
#define VM_LEAF_BASE(result_type, header) \
debug_only(NoHandleMark __hm;) \
os::verify_stack_alignment(); \
/* begin of body */
#define VM_ENTRY_BASE_FROM_LEAF(result_type, header, thread) \
debug_only(ResetNoHandleMark __rnhm;) \
HandleMarkCleaner __hm(thread); \
Thread* THREAD = thread; \
os::verify_stack_alignment(); \
/* begin of body */
// ENTRY routines may lock, GC and throw exceptions
#define VM_ENTRY_BASE(result_type, header, thread) \
HandleMarkCleaner __hm(thread); \
Thread* THREAD = thread; \
os::verify_stack_alignment(); \
/* begin of body */
#define JRT_ENTRY(result_type, header) \
result_type header { \
ThreadInVMfromJava __tiv(thread); \
VM_ENTRY_BASE(result_type, header, thread) \
debug_only(VMEntryWrapper __vew;)
// JRT_LEAF currently can be called from either _thread_in_Java or
// _thread_in_native mode.
//
// JRT_LEAF rules:
// A JRT_LEAF method may not interfere with safepointing by
// 1) acquiring or blocking on a Mutex or JavaLock - checked
// 2) allocating heap memory - checked
// 3) executing a VM operation - checked
// 4) executing a system call (including malloc) that could block or grab a lock
// 5) invoking GC
// 6) reaching a safepoint
// 7) running too long
// Nor may any method it calls.
#define JRT_LEAF(result_type, header) \
result_type header { \
VM_LEAF_BASE(result_type, header) \
debug_only(NoSafepointVerifier __nsv;)
#define JRT_ENTRY_NO_ASYNC(result_type, header) \
result_type header { \
ThreadInVMfromJava __tiv(thread, false /* check asyncs */); \
VM_ENTRY_BASE(result_type, header, thread) \
debug_only(VMEntryWrapper __vew;)
// Same as JRT Entry but allows for return value after the safepoint
// to get back into Java from the VM
#define JRT_BLOCK_ENTRY(result_type, header) \
result_type header { \
HandleMarkCleaner __hm(thread);
#define JRT_BLOCK \
{ \
ThreadInVMfromJava __tiv(thread); \
Thread* THREAD = thread; \
debug_only(VMEntryWrapper __vew;)
#define JRT_BLOCK_NO_ASYNC \
{ \
ThreadInVMfromJava __tiv(thread, false /* check asyncs */); \
Thread* THREAD = thread; \
debug_only(VMEntryWrapper __vew;)
#define JRT_BLOCK_END }
#define JRT_END }
// Definitions for JNI
#define JNI_ENTRY(result_type, header) \
JNI_ENTRY_NO_PRESERVE(result_type, header) \
WeakPreserveExceptionMark __wem(thread);
#define JNI_ENTRY_NO_PRESERVE(result_type, header) \
extern "C" { \
result_type JNICALL header { \
JavaThread* thread=JavaThread::thread_from_jni_environment(env); \
assert( !VerifyJNIEnvThread || (thread == Thread::current()), "JNIEnv is only valid in same thread"); \
ThreadInVMfromNative __tiv(thread); \
debug_only(VMNativeEntryWrapper __vew;) \
VM_ENTRY_BASE(result_type, header, thread)
#define JNI_LEAF(result_type, header) \
extern "C" { \
result_type JNICALL header { \
JavaThread* thread=JavaThread::thread_from_jni_environment(env); \
assert( !VerifyJNIEnvThread || (thread == Thread::current()), "JNIEnv is only valid in same thread"); \
VM_LEAF_BASE(result_type, header)
// Close the routine and the extern "C"
#define JNI_END } }
// Definitions for JVM
#define JVM_ENTRY(result_type, header) \
extern "C" { \
result_type JNICALL header { \
JavaThread* thread=JavaThread::thread_from_jni_environment(env); \
ThreadInVMfromNative __tiv(thread); \
debug_only(VMNativeEntryWrapper __vew;) \
VM_ENTRY_BASE(result_type, header, thread)
#define JVM_ENTRY_NO_ENV(result_type, header) \
extern "C" { \
result_type JNICALL header { \
JavaThread* thread = JavaThread::current(); \
ThreadInVMfromNative __tiv(thread); \
debug_only(VMNativeEntryWrapper __vew;) \
VM_ENTRY_BASE(result_type, header, thread)
#define JVM_LEAF(result_type, header) \
extern "C" { \
result_type JNICALL header { \
VM_Exit::block_if_vm_exited(); \
VM_LEAF_BASE(result_type, header)
#define JVM_ENTRY_FROM_LEAF(env, result_type, header) \
{ { \
JavaThread* thread=JavaThread::thread_from_jni_environment(env); \
ThreadInVMfromNative __tiv(thread); \
debug_only(VMNativeEntryWrapper __vew;) \
VM_ENTRY_BASE_FROM_LEAF(result_type, header, thread)
#define JVM_END } }
#endif // SHARE_RUNTIME_INTERFACESUPPORT_INLINE_HPP