jdk

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/*
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 * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 *
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 * This code is free software; you can redistribute it and/or modify it
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 * under the terms of the GNU General Public License version 2 only, as
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 * published by the Free Software Foundation.
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 *
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 * This code is distributed in the hope that it will be useful, but WITHOUT
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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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 * version 2 for more details (a copy is included in the LICENSE file that
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 * accompanied this code).
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 *
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 * You should have received a copy of the GNU General Public License version
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 * 2 along with this work; if not, write to the Free Software Foundation,
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 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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 *
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 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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 * or visit www.oracle.com if you need additional information or have any
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 * questions.
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 *
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 */
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#include "precompiled.hpp"
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#include "classfile/classLoaderDataGraph.hpp"
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#include "classfile/javaClasses.inline.hpp"
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#include "classfile/moduleEntry.hpp"
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#include "classfile/symbolTable.hpp"
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#include "classfile/vmSymbols.hpp"
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#include "jvmtifiles/jvmtiEnv.hpp"
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#include "memory/iterator.hpp"
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#include "memory/resourceArea.hpp"
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#include "oops/klass.inline.hpp"
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#include "oops/objArrayKlass.hpp"
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#include "oops/objArrayOop.hpp"
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#include "oops/oop.inline.hpp"
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#include "oops/oopHandle.inline.hpp"
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#include "prims/jvmtiEnvBase.hpp"
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#include "prims/jvmtiEventController.inline.hpp"
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#include "prims/jvmtiExtensions.hpp"
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#include "prims/jvmtiImpl.hpp"
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#include "prims/jvmtiManageCapabilities.hpp"
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#include "prims/jvmtiTagMap.hpp"
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#include "prims/jvmtiThreadState.inline.hpp"
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#include "runtime/continuationEntry.inline.hpp"
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#include "runtime/deoptimization.hpp"
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#include "runtime/frame.inline.hpp"
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#include "runtime/handles.inline.hpp"
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#include "runtime/interfaceSupport.inline.hpp"
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#include "runtime/javaCalls.hpp"
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#include "runtime/javaThread.inline.hpp"
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#include "runtime/jfieldIDWorkaround.hpp"
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#include "runtime/jniHandles.inline.hpp"
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#include "runtime/objectMonitor.inline.hpp"
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#include "runtime/osThread.hpp"
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#include "runtime/signature.hpp"
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#include "runtime/stackWatermarkSet.inline.hpp"
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#include "runtime/threads.hpp"
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#include "runtime/threadSMR.inline.hpp"
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#include "runtime/vframe.inline.hpp"
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#include "runtime/vframe_hp.hpp"
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#include "runtime/vmThread.hpp"
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#include "runtime/vmOperations.hpp"
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#include "services/threadService.hpp"
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67

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///////////////////////////////////////////////////////////////
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//
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// JvmtiEnvBase
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//
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JvmtiEnvBase* JvmtiEnvBase::_head_environment = nullptr;
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bool JvmtiEnvBase::_globally_initialized = false;
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volatile bool JvmtiEnvBase::_needs_clean_up = false;
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jvmtiPhase JvmtiEnvBase::_phase = JVMTI_PHASE_PRIMORDIAL;
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volatile int JvmtiEnvBase::_dying_thread_env_iteration_count = 0;
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extern jvmtiInterface_1_ jvmti_Interface;
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extern jvmtiInterface_1_ jvmtiTrace_Interface;
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85

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// perform initializations that must occur before any JVMTI environments
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// are released but which should only be initialized once (no matter
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// how many environments are created).
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void
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JvmtiEnvBase::globally_initialize() {
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  assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check");
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  assert(_globally_initialized == false, "bad call");
93

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  JvmtiManageCapabilities::initialize();
95

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  // register extension functions and events
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  JvmtiExtensions::register_extensions();
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#ifdef JVMTI_TRACE
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  JvmtiTrace::initialize();
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#endif
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  _globally_initialized = true;
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}
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106

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void
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JvmtiEnvBase::initialize() {
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  assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check");
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  // Add this environment to the end of the environment list (order is important)
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  {
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    // This block of code must not contain any safepoints, as list deallocation
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    // (which occurs at a safepoint) cannot occur simultaneously with this list
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    // addition.  Note: NoSafepointVerifier cannot, currently, be used before
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    // threads exist.
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    JvmtiEnvIterator it;
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    JvmtiEnvBase *previous_env = nullptr;
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    for (JvmtiEnvBase* env = it.first(); env != nullptr; env = it.next(env)) {
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      previous_env = env;
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    }
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    if (previous_env == nullptr) {
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      _head_environment = this;
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    } else {
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      previous_env->set_next_environment(this);
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    }
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  }
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  if (_globally_initialized == false) {
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    globally_initialize();
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  }
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}
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jvmtiPhase
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JvmtiEnvBase::phase() {
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  // For the JVMTI environments possessed the can_generate_early_vmstart:
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  //   replace JVMTI_PHASE_PRIMORDIAL with JVMTI_PHASE_START
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  if (_phase == JVMTI_PHASE_PRIMORDIAL &&
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      JvmtiExport::early_vmstart_recorded() &&
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      early_vmstart_env()) {
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    return JVMTI_PHASE_START;
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  }
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  return _phase; // Normal case
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}
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bool
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JvmtiEnvBase::is_valid() {
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  jlong value = 0;
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  // This object might not be a JvmtiEnvBase so we can't assume
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  // the _magic field is properly aligned. Get the value in a safe
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  // way and then check against JVMTI_MAGIC.
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  switch (sizeof(_magic)) {
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  case 2:
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    value = Bytes::get_native_u2((address)&_magic);
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    break;
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  case 4:
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    value = Bytes::get_native_u4((address)&_magic);
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    break;
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  case 8:
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    value = Bytes::get_native_u8((address)&_magic);
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    break;
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  default:
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    guarantee(false, "_magic field is an unexpected size");
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  }
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  return value == JVMTI_MAGIC;
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}
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bool
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JvmtiEnvBase::use_version_1_0_semantics() {
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  int major, minor, micro;
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  JvmtiExport::decode_version_values(_version, &major, &minor, &micro);
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  return major == 1 && minor == 0;  // micro version doesn't matter here
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}
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183

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bool
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JvmtiEnvBase::use_version_1_1_semantics() {
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  int major, minor, micro;
187

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  JvmtiExport::decode_version_values(_version, &major, &minor, &micro);
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  return major == 1 && minor == 1;  // micro version doesn't matter here
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}
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bool
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JvmtiEnvBase::use_version_1_2_semantics() {
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  int major, minor, micro;
195

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  JvmtiExport::decode_version_values(_version, &major, &minor, &micro);
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  return major == 1 && minor == 2;  // micro version doesn't matter here
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}
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JvmtiEnvBase::JvmtiEnvBase(jint version) : _env_event_enable() {
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  _version = version;
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  _env_local_storage = nullptr;
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  _tag_map = nullptr;
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  _native_method_prefix_count = 0;
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  _native_method_prefixes = nullptr;
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  _next = nullptr;
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  _class_file_load_hook_ever_enabled = false;
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  // Moot since ClassFileLoadHook not yet enabled.
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  // But "true" will give a more predictable ClassFileLoadHook behavior
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  // for environment creation during ClassFileLoadHook.
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  _is_retransformable = true;
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  // all callbacks initially null
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  memset(&_event_callbacks, 0, sizeof(jvmtiEventCallbacks));
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  memset(&_ext_event_callbacks, 0, sizeof(jvmtiExtEventCallbacks));
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  // all capabilities initially off
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  memset(&_current_capabilities, 0, sizeof(_current_capabilities));
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  // all prohibited capabilities initially off
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  memset(&_prohibited_capabilities, 0, sizeof(_prohibited_capabilities));
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  _magic = JVMTI_MAGIC;
226

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  JvmtiEventController::env_initialize((JvmtiEnv*)this);
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#ifdef JVMTI_TRACE
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  _jvmti_external.functions = TraceJVMTI != nullptr ? &jvmtiTrace_Interface : &jvmti_Interface;
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#else
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  _jvmti_external.functions = &jvmti_Interface;
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#endif
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}
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236

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void
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JvmtiEnvBase::dispose() {
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#ifdef JVMTI_TRACE
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  JvmtiTrace::shutdown();
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#endif
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  // Dispose of event info and let the event controller call us back
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  // in a locked state (env_dispose, below)
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  JvmtiEventController::env_dispose(this);
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}
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void
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JvmtiEnvBase::env_dispose() {
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  assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check");
252

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  // We have been entered with all events disabled on this environment.
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  // A race to re-enable events (by setting callbacks) is prevented by
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  // checking for a valid environment when setting callbacks (while
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  // holding the JvmtiThreadState_lock).
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  // Mark as invalid.
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  _magic = DISPOSED_MAGIC;
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  // Relinquish all capabilities.
262
  jvmtiCapabilities *caps = get_capabilities();
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  JvmtiManageCapabilities::relinquish_capabilities(caps, caps, caps);
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  // Same situation as with events (see above)
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  set_native_method_prefixes(0, nullptr);
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  JvmtiTagMap* tag_map_to_clear = tag_map_acquire();
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  // A tag map can be big, clear it now to save memory until
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  // the destructor runs.
271
  if (tag_map_to_clear != nullptr) {
272
    tag_map_to_clear->clear();
273
  }
274

275
  _needs_clean_up = true;
276
}
277

278

279
JvmtiEnvBase::~JvmtiEnvBase() {
280
  assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
281

282
  // There is a small window of time during which the tag map of a
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  // disposed environment could have been reallocated.
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  // Make sure it is gone.
285
  JvmtiTagMap* tag_map_to_deallocate = _tag_map;
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  set_tag_map(nullptr);
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  // A tag map can be big, deallocate it now
288
  if (tag_map_to_deallocate != nullptr) {
289
    delete tag_map_to_deallocate;
290
  }
291

292
  _magic = BAD_MAGIC;
293
}
294

295

296
void
297
JvmtiEnvBase::periodic_clean_up() {
298
  assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
299

300
  // JvmtiEnvBase reference is saved in JvmtiEnvThreadState. So
301
  // clean up JvmtiThreadState before deleting JvmtiEnv pointer.
302
  JvmtiThreadState::periodic_clean_up();
303

304
  // Unlink all invalid environments from the list of environments
305
  // and deallocate them
306
  JvmtiEnvIterator it;
307
  JvmtiEnvBase* previous_env = nullptr;
308
  JvmtiEnvBase* env = it.first();
309
  while (env != nullptr) {
310
    if (env->is_valid()) {
311
      previous_env = env;
312
      env = it.next(env);
313
    } else {
314
      // This one isn't valid, remove it from the list and deallocate it
315
      JvmtiEnvBase* defunct_env = env;
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      env = it.next(env);
317
      if (previous_env == nullptr) {
318
        _head_environment = env;
319
      } else {
320
        previous_env->set_next_environment(env);
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      }
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      delete defunct_env;
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    }
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  }
325

326
}
327

328

329
void
330
JvmtiEnvBase::check_for_periodic_clean_up() {
331
  assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
332

333
  class ThreadInsideIterationClosure: public ThreadClosure {
334
   private:
335
    bool _inside;
336
   public:
337
    ThreadInsideIterationClosure() : _inside(false) {};
338

339
    void do_thread(Thread* thread) {
340
      _inside |= thread->is_inside_jvmti_env_iteration();
341
    }
342

343
    bool is_inside_jvmti_env_iteration() {
344
      return _inside;
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    }
346
  };
347

348
  if (_needs_clean_up) {
349
    // Check if we are currently iterating environment,
350
    // deallocation should not occur if we are
351
    ThreadInsideIterationClosure tiic;
352
    Threads::threads_do(&tiic);
353
    if (!tiic.is_inside_jvmti_env_iteration() &&
354
             !is_inside_dying_thread_env_iteration()) {
355
      _needs_clean_up = false;
356
      JvmtiEnvBase::periodic_clean_up();
357
    }
358
  }
359
}
360

361

362
void
363
JvmtiEnvBase::record_first_time_class_file_load_hook_enabled() {
364
  assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(),
365
         "sanity check");
366

367
  if (!_class_file_load_hook_ever_enabled) {
368
    _class_file_load_hook_ever_enabled = true;
369

370
    if (get_capabilities()->can_retransform_classes) {
371
      _is_retransformable = true;
372
    } else {
373
      _is_retransformable = false;
374

375
      // cannot add retransform capability after ClassFileLoadHook has been enabled
376
      get_prohibited_capabilities()->can_retransform_classes = 1;
377
    }
378
  }
379
}
380

381

382
void
383
JvmtiEnvBase::record_class_file_load_hook_enabled() {
384
  if (!_class_file_load_hook_ever_enabled) {
385
    if (Threads::number_of_threads() == 0) {
386
      record_first_time_class_file_load_hook_enabled();
387
    } else {
388
      MutexLocker mu(JvmtiThreadState_lock);
389
      record_first_time_class_file_load_hook_enabled();
390
    }
391
  }
392
}
393

394

395
jvmtiError
396
JvmtiEnvBase::set_native_method_prefixes(jint prefix_count, char** prefixes) {
397
  assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(),
398
         "sanity check");
399

400
  int old_prefix_count = get_native_method_prefix_count();
401
  char **old_prefixes = get_native_method_prefixes();
402

403
  // allocate and install the new prefixex
404
  if (prefix_count == 0 || !is_valid()) {
405
    _native_method_prefix_count = 0;
406
    _native_method_prefixes = nullptr;
407
  } else {
408
    // there are prefixes, allocate an array to hold them, and fill it
409
    char** new_prefixes = (char**)os::malloc((prefix_count) * sizeof(char*), mtInternal);
410
    if (new_prefixes == nullptr) {
411
      return JVMTI_ERROR_OUT_OF_MEMORY;
412
    }
413
    for (int i = 0; i < prefix_count; i++) {
414
      char* prefix = prefixes[i];
415
      if (prefix == nullptr) {
416
        for (int j = 0; j < (i-1); j++) {
417
          os::free(new_prefixes[j]);
418
        }
419
        os::free(new_prefixes);
420
        return JVMTI_ERROR_NULL_POINTER;
421
      }
422
      prefix = os::strdup(prefixes[i]);
423
      if (prefix == nullptr) {
424
        for (int j = 0; j < (i-1); j++) {
425
          os::free(new_prefixes[j]);
426
        }
427
        os::free(new_prefixes);
428
        return JVMTI_ERROR_OUT_OF_MEMORY;
429
      }
430
      new_prefixes[i] = prefix;
431
    }
432
    _native_method_prefix_count = prefix_count;
433
    _native_method_prefixes = new_prefixes;
434
  }
435

436
  // now that we know the new prefixes have been successfully installed we can
437
  // safely remove the old ones
438
  if (old_prefix_count != 0) {
439
    for (int i = 0; i < old_prefix_count; i++) {
440
      os::free(old_prefixes[i]);
441
    }
442
    os::free(old_prefixes);
443
  }
444

445
  return JVMTI_ERROR_NONE;
446
}
447

448

449
// Collect all the prefixes which have been set in any JVM TI environments
450
// by the SetNativeMethodPrefix(es) functions.  Be sure to maintain the
451
// order of environments and the order of prefixes within each environment.
452
// Return in a resource allocated array.
453
char**
454
JvmtiEnvBase::get_all_native_method_prefixes(int* count_ptr) {
455
  assert(Threads::number_of_threads() == 0 ||
456
         SafepointSynchronize::is_at_safepoint() ||
457
         JvmtiThreadState_lock->is_locked(),
458
         "sanity check");
459

460
  int total_count = 0;
461
  GrowableArray<char*>* prefix_array =new GrowableArray<char*>(5);
462

463
  JvmtiEnvIterator it;
464
  for (JvmtiEnvBase* env = it.first(); env != nullptr; env = it.next(env)) {
465
    int prefix_count = env->get_native_method_prefix_count();
466
    char** prefixes = env->get_native_method_prefixes();
467
    for (int j = 0; j < prefix_count; j++) {
468
      // retrieve a prefix and so that it is safe against asynchronous changes
469
      // copy it into the resource area
470
      char* prefix = prefixes[j];
471
      char* prefix_copy = NEW_RESOURCE_ARRAY(char, strlen(prefix)+1);
472
      strcpy(prefix_copy, prefix);
473
      prefix_array->at_put_grow(total_count++, prefix_copy);
474
    }
475
  }
476

477
  char** all_prefixes = NEW_RESOURCE_ARRAY(char*, total_count);
478
  char** p = all_prefixes;
479
  for (int i = 0; i < total_count; ++i) {
480
    *p++ = prefix_array->at(i);
481
  }
482
  *count_ptr = total_count;
483
  return all_prefixes;
484
}
485

486
void
487
JvmtiEnvBase::set_event_callbacks(const jvmtiEventCallbacks* callbacks,
488
                                               jint size_of_callbacks) {
489
  assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check");
490

491
  size_t byte_cnt = sizeof(jvmtiEventCallbacks);
492

493
  // clear in either case to be sure we got any gap between sizes
494
  memset(&_event_callbacks, 0, byte_cnt);
495

496
  // Now that JvmtiThreadState_lock is held, prevent a possible race condition where events
497
  // are re-enabled by a call to set event callbacks where the DisposeEnvironment
498
  // occurs after the boiler-plate environment check and before the lock is acquired.
499
  if (callbacks != nullptr && is_valid()) {
500
    if (size_of_callbacks < (jint)byte_cnt) {
501
      byte_cnt = size_of_callbacks;
502
    }
503
    memcpy(&_event_callbacks, callbacks, byte_cnt);
504
  }
505
}
506

507

508
// In the fullness of time, all users of the method should instead
509
// directly use allocate, besides being cleaner and faster, this will
510
// mean much better out of memory handling
511
unsigned char *
512
JvmtiEnvBase::jvmtiMalloc(jlong size) {
513
  unsigned char* mem = nullptr;
514
  jvmtiError result = allocate(size, &mem);
515
  assert(result == JVMTI_ERROR_NONE, "Allocate failed");
516
  return mem;
517
}
518

519

520
// Handle management
521

522
jobject JvmtiEnvBase::jni_reference(Handle hndl) {
523
  return JNIHandles::make_local(hndl());
524
}
525

526
jobject JvmtiEnvBase::jni_reference(JavaThread *thread, Handle hndl) {
527
  return JNIHandles::make_local(thread, hndl());
528
}
529

530
void JvmtiEnvBase::destroy_jni_reference(jobject jobj) {
531
  JNIHandles::destroy_local(jobj);
532
}
533

534
void JvmtiEnvBase::destroy_jni_reference(JavaThread *thread, jobject jobj) {
535
  JNIHandles::destroy_local(jobj); // thread is unused.
536
}
537

538
//
539
// Threads
540
//
541

542
jthread *
543
JvmtiEnvBase::new_jthreadArray(int length, Handle *handles) {
544
  if (length == 0) {
545
    return nullptr;
546
  }
547

548
  jthread* objArray = (jthread *) jvmtiMalloc(sizeof(jthread) * length);
549
  NULL_CHECK(objArray, nullptr);
550

551
  for (int i = 0; i < length; i++) {
552
    objArray[i] = (jthread)jni_reference(handles[i]);
553
  }
554
  return objArray;
555
}
556

557
jthreadGroup *
558
JvmtiEnvBase::new_jthreadGroupArray(int length, objArrayHandle groups) {
559
  if (length == 0) {
560
    return nullptr;
561
  }
562

563
  jthreadGroup* objArray = (jthreadGroup *) jvmtiMalloc(sizeof(jthreadGroup) * length);
564
  NULL_CHECK(objArray, nullptr);
565

566
  for (int i = 0; i < length; i++) {
567
    objArray[i] = (jthreadGroup)JNIHandles::make_local(groups->obj_at(i));
568
  }
569
  return objArray;
570
}
571

572
// Return the vframe on the specified thread and depth, null if no such frame.
573
// The thread and the oops in the returned vframe might not have been processed.
574
javaVFrame*
575
JvmtiEnvBase::jvf_for_thread_and_depth(JavaThread* java_thread, jint depth) {
576
  if (!java_thread->has_last_Java_frame()) {
577
    return nullptr;
578
  }
579
  RegisterMap reg_map(java_thread,
580
                      RegisterMap::UpdateMap::include,
581
                      RegisterMap::ProcessFrames::skip,
582
                      RegisterMap::WalkContinuation::include);
583
  javaVFrame *jvf = java_thread->last_java_vframe(&reg_map);
584

585
  jvf = JvmtiEnvBase::check_and_skip_hidden_frames(java_thread, jvf);
586

587
  for (int d = 0; jvf != nullptr && d < depth; d++) {
588
    jvf = jvf->java_sender();
589
  }
590
  return jvf;
591
}
592

593
//
594
// utilities: JNI objects
595
//
596

597

598
jclass
599
JvmtiEnvBase::get_jni_class_non_null(Klass* k) {
600
  assert(k != nullptr, "k != null");
601
  Thread *thread = Thread::current();
602
  return (jclass)jni_reference(Handle(thread, k->java_mirror()));
603
}
604

605
//
606
// Field Information
607
//
608

609
bool
610
JvmtiEnvBase::get_field_descriptor(Klass* k, jfieldID field, fieldDescriptor* fd) {
611
  if (!jfieldIDWorkaround::is_valid_jfieldID(k, field)) {
612
    return false;
613
  }
614
  bool found = false;
615
  if (jfieldIDWorkaround::is_static_jfieldID(field)) {
616
    JNIid* id = jfieldIDWorkaround::from_static_jfieldID(field);
617
    found = id->find_local_field(fd);
618
  } else {
619
    // Non-static field. The fieldID is really the offset of the field within the object.
620
    int offset = jfieldIDWorkaround::from_instance_jfieldID(k, field);
621
    found = InstanceKlass::cast(k)->find_field_from_offset(offset, false, fd);
622
  }
623
  return found;
624
}
625

626
bool
627
JvmtiEnvBase::is_vthread_alive(oop vt) {
628
  oop cont = java_lang_VirtualThread::continuation(vt);
629
  return !jdk_internal_vm_Continuation::done(cont) &&
630
         java_lang_VirtualThread::state(vt) != java_lang_VirtualThread::NEW;
631
}
632

633
// Return JavaThread if virtual thread is mounted, null otherwise.
634
JavaThread* JvmtiEnvBase::get_JavaThread_or_null(oop vthread) {
635
  oop carrier_thread = java_lang_VirtualThread::carrier_thread(vthread);
636
  if (carrier_thread == nullptr) {
637
    return nullptr;
638
  }
639

640
  JavaThread* java_thread = java_lang_Thread::thread(carrier_thread);
641

642
  // This could be a different thread to the current one. So we need to ensure that
643
  // processing has started before we are allowed to read the continuation oop of
644
  // another thread, as it is a direct root of that other thread.
645
  StackWatermarkSet::start_processing(java_thread, StackWatermarkKind::gc);
646

647
  oop cont = java_lang_VirtualThread::continuation(vthread);
648
  assert(cont != nullptr, "must be");
649
  assert(Continuation::continuation_scope(cont) == java_lang_VirtualThread::vthread_scope(), "must be");
650
  return Continuation::is_continuation_mounted(java_thread, cont) ? java_thread : nullptr;
651
}
652

653
javaVFrame*
654
JvmtiEnvBase::check_and_skip_hidden_frames(bool is_in_VTMS_transition, javaVFrame* jvf) {
655
  // The second condition is needed to hide notification methods.
656
  if (!is_in_VTMS_transition && (jvf == nullptr || !jvf->method()->jvmti_mount_transition())) {
657
    return jvf;  // No frames to skip.
658
  }
659
  // Find jvf with a method annotated with @JvmtiMountTransition.
660
  for ( ; jvf != nullptr; jvf = jvf->java_sender()) {
661
    if (jvf->method()->jvmti_mount_transition()) {  // Cannot actually appear in an unmounted continuation; they're never frozen.
662
      jvf = jvf->java_sender();  // Skip annotated method.
663
      break;
664
    }
665
    if (jvf->method()->changes_current_thread()) {
666
      break;
667
    }
668
    // Skip frame above annotated method.
669
  }
670
  return jvf;
671
}
672

673
javaVFrame*
674
JvmtiEnvBase::check_and_skip_hidden_frames(JavaThread* jt, javaVFrame* jvf) {
675
  jvf = check_and_skip_hidden_frames(jt->is_in_VTMS_transition(), jvf);
676
  return jvf;
677
}
678

679
javaVFrame*
680
JvmtiEnvBase::check_and_skip_hidden_frames(oop vthread, javaVFrame* jvf) {
681
  JvmtiThreadState* state = java_lang_Thread::jvmti_thread_state(vthread);
682
  if (state == nullptr) {
683
    // nothing to skip
684
    return jvf;
685
  }
686
  jvf = check_and_skip_hidden_frames(java_lang_Thread::is_in_VTMS_transition(vthread), jvf);
687
  return jvf;
688
}
689

690
javaVFrame*
691
JvmtiEnvBase::get_vthread_jvf(oop vthread) {
692
  assert(java_lang_VirtualThread::state(vthread) != java_lang_VirtualThread::NEW, "sanity check");
693
  assert(java_lang_VirtualThread::state(vthread) != java_lang_VirtualThread::TERMINATED, "sanity check");
694

695
  Thread* cur_thread = Thread::current();
696
  oop cont = java_lang_VirtualThread::continuation(vthread);
697
  javaVFrame* jvf = nullptr;
698

699
  JavaThread* java_thread = get_JavaThread_or_null(vthread);
700
  if (java_thread != nullptr) {
701
    if (!java_thread->has_last_Java_frame()) {
702
      // TBD: This is a temporary work around to avoid a guarantee caused by
703
      // the native enterSpecial frame on the top. No frames will be found
704
      // by the JVMTI functions such as GetStackTrace.
705
      return nullptr;
706
    }
707
    vframeStream vfs(java_thread);
708
    jvf = vfs.at_end() ? nullptr : vfs.asJavaVFrame();
709
    jvf = check_and_skip_hidden_frames(java_thread, jvf);
710
  } else {
711
    vframeStream vfs(cont);
712
    jvf = vfs.at_end() ? nullptr : vfs.asJavaVFrame();
713
    jvf = check_and_skip_hidden_frames(vthread, jvf);
714
  }
715
  return jvf;
716
}
717

718
// Return correct javaVFrame for a carrier (non-virtual) thread.
719
// It strips vthread frames at the top if there are any.
720
javaVFrame*
721
JvmtiEnvBase::get_cthread_last_java_vframe(JavaThread* jt, RegisterMap* reg_map_p) {
722
  // Strip vthread frames in case of carrier thread with mounted continuation.
723
  bool cthread_with_cont = JvmtiEnvBase::is_cthread_with_continuation(jt);
724
  javaVFrame *jvf = cthread_with_cont ? jt->carrier_last_java_vframe(reg_map_p)
725
                                      : jt->last_java_vframe(reg_map_p);
726
  // Skip hidden frames only for carrier threads
727
  // which are in non-temporary VTMS transition.
728
  if (jt->is_in_VTMS_transition()) {
729
    jvf = check_and_skip_hidden_frames(jt, jvf);
730
  }
731
  return jvf;
732
}
733

734
jint
735
JvmtiEnvBase::get_thread_state_base(oop thread_oop, JavaThread* jt) {
736
  jint state = 0;
737

738
  if (thread_oop != nullptr) {
739
    // Get most state bits.
740
    state = (jint)java_lang_Thread::get_thread_status(thread_oop);
741
  }
742
  if (jt != nullptr) {
743
    // We have a JavaThread* so add more state bits.
744
    JavaThreadState jts = jt->thread_state();
745

746
    if (jt->is_carrier_thread_suspended() ||
747
        ((jt->jvmti_vthread() == nullptr || jt->jvmti_vthread() == thread_oop) && jt->is_suspended())) {
748
      // Suspended non-virtual thread.
749
      state |= JVMTI_THREAD_STATE_SUSPENDED;
750
    }
751
    if (jts == _thread_in_native) {
752
      state |= JVMTI_THREAD_STATE_IN_NATIVE;
753
    }
754
    if (jt->is_interrupted(false)) {
755
      state |= JVMTI_THREAD_STATE_INTERRUPTED;
756
    }
757
  }
758
  return state;
759
}
760

761
jint
762
JvmtiEnvBase::get_thread_state(oop thread_oop, JavaThread* jt) {
763
  jint state = 0;
764

765
  if (is_thread_carrying_vthread(jt, thread_oop)) {
766
    state = (jint)java_lang_Thread::get_thread_status(thread_oop);
767

768
    // This is for extra safety. Other bits are not expected nor needed.
769
    state &= (JVMTI_THREAD_STATE_ALIVE | JVMTI_THREAD_STATE_INTERRUPTED);
770

771
    if (jt->is_carrier_thread_suspended()) {
772
      state |= JVMTI_THREAD_STATE_SUSPENDED;
773
    }
774
    // It's okay for the JVMTI state to be reported as WAITING when waiting
775
    // for something other than an Object.wait. So, we treat a thread carrying
776
    // a virtual thread as waiting indefinitely which is not runnable.
777
    // It is why the RUNNABLE bit is not needed and the WAITING bits are added.
778
    state |= JVMTI_THREAD_STATE_WAITING | JVMTI_THREAD_STATE_WAITING_INDEFINITELY;
779
  } else {
780
    state = get_thread_state_base(thread_oop, jt);
781
  }
782
  return state;
783
}
784

785
jint
786
JvmtiEnvBase::get_vthread_state(oop thread_oop, JavaThread* java_thread) {
787
  jint state = 0;
788
  bool ext_suspended = JvmtiVTSuspender::is_vthread_suspended(thread_oop);
789
  jint interrupted = java_lang_Thread::interrupted(thread_oop);
790

791
  if (java_thread != nullptr) {
792
    // If virtual thread is blocked on a monitor enter the BLOCKED_ON_MONITOR_ENTER bit
793
    // is set for carrier thread instead of virtual.
794
    // Other state bits except filtered ones are expected to be the same.
795
    oop ct_oop = java_lang_VirtualThread::carrier_thread(thread_oop);
796
    jint filtered_bits = JVMTI_THREAD_STATE_SUSPENDED | JVMTI_THREAD_STATE_INTERRUPTED;
797

798
    // This call can trigger a safepoint, so thread_oop must not be used after it.
799
    state = get_thread_state_base(ct_oop, java_thread) & ~filtered_bits;
800
  } else {
801
    int vt_state = java_lang_VirtualThread::state(thread_oop);
802
    state = (jint)java_lang_VirtualThread::map_state_to_thread_status(vt_state);
803
  }
804
  // Ensure the thread has not exited after retrieving suspended/interrupted values.
805
  if ((state & JVMTI_THREAD_STATE_ALIVE) != 0) {
806
    if (ext_suspended) {
807
      state |= JVMTI_THREAD_STATE_SUSPENDED;
808
    }
809
    if (interrupted) {
810
      state |= JVMTI_THREAD_STATE_INTERRUPTED;
811
    }
812
  }
813
  return state;
814
}
815

816
jint
817
JvmtiEnvBase::get_thread_or_vthread_state(oop thread_oop, JavaThread* java_thread) {
818
  jint state = 0;
819
  if (java_lang_VirtualThread::is_instance(thread_oop)) {
820
    state = JvmtiEnvBase::get_vthread_state(thread_oop, java_thread);
821
  } else {
822
    state = JvmtiEnvBase::get_thread_state(thread_oop, java_thread);
823
  }
824
  return state;
825
}
826

827
jvmtiError
828
JvmtiEnvBase::get_live_threads(JavaThread* current_thread, Handle group_hdl, jint *count_ptr, Handle **thread_objs_p) {
829
  jint count = 0;
830
  Handle *thread_objs = nullptr;
831
  ThreadsListEnumerator tle(current_thread, /* include_jvmti_agent_threads */ true);
832
  int nthreads = tle.num_threads();
833
  if (nthreads > 0) {
834
    thread_objs = NEW_RESOURCE_ARRAY_RETURN_NULL(Handle, nthreads);
835
    NULL_CHECK(thread_objs, JVMTI_ERROR_OUT_OF_MEMORY);
836
    for (int i = 0; i < nthreads; i++) {
837
      Handle thread = tle.get_threadObj(i);
838
      if (thread()->is_a(vmClasses::Thread_klass()) && java_lang_Thread::threadGroup(thread()) == group_hdl()) {
839
        thread_objs[count++] = thread;
840
      }
841
    }
842
  }
843
  *thread_objs_p = thread_objs;
844
  *count_ptr = count;
845
  return JVMTI_ERROR_NONE;
846
}
847

848
jvmtiError
849
JvmtiEnvBase::get_subgroups(JavaThread* current_thread, Handle group_hdl, jint *count_ptr, objArrayHandle *group_objs_p) {
850

851
  // This call collects the strong and weak groups
852
  JavaThread* THREAD = current_thread;
853
  JavaValue result(T_OBJECT);
854
  JavaCalls::call_virtual(&result,
855
                          group_hdl,
856
                          vmClasses::ThreadGroup_klass(),
857
                          SymbolTable::new_permanent_symbol("subgroupsAsArray"),
858
                          vmSymbols::void_threadgroup_array_signature(),
859
                          THREAD);
860
  if (HAS_PENDING_EXCEPTION) {
861
    Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
862
    CLEAR_PENDING_EXCEPTION;
863
    if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
864
      return JVMTI_ERROR_OUT_OF_MEMORY;
865
    } else {
866
      return JVMTI_ERROR_INTERNAL;
867
    }
868
  }
869

870
  assert(result.get_type() == T_OBJECT, "just checking");
871
  objArrayOop groups = (objArrayOop)result.get_oop();
872

873
  *count_ptr = groups == nullptr ? 0 : groups->length();
874
  *group_objs_p = objArrayHandle(current_thread, groups);
875

876
  return JVMTI_ERROR_NONE;
877
}
878

879
//
880
// Object Monitor Information
881
//
882

883
//
884
// Count the number of objects for a lightweight monitor. The hobj
885
// parameter is object that owns the monitor so this routine will
886
// count the number of times the same object was locked by frames
887
// in java_thread.
888
//
889
jint
890
JvmtiEnvBase::count_locked_objects(JavaThread *java_thread, Handle hobj) {
891
  jint ret = 0;
892
  if (!java_thread->has_last_Java_frame()) {
893
    return ret;  // no Java frames so no monitors
894
  }
895

896
  Thread* current_thread = Thread::current();
897
  ResourceMark rm(current_thread);
898
  HandleMark   hm(current_thread);
899
  RegisterMap  reg_map(java_thread,
900
                       RegisterMap::UpdateMap::include,
901
                       RegisterMap::ProcessFrames::include,
902
                       RegisterMap::WalkContinuation::skip);
903

904
  for (javaVFrame *jvf = java_thread->last_java_vframe(&reg_map); jvf != nullptr;
905
       jvf = jvf->java_sender()) {
906
    GrowableArray<MonitorInfo*>* mons = jvf->monitors();
907
    if (!mons->is_empty()) {
908
      for (int i = 0; i < mons->length(); i++) {
909
        MonitorInfo *mi = mons->at(i);
910
        if (mi->owner_is_scalar_replaced()) continue;
911

912
        // see if owner of the monitor is our object
913
        if (mi->owner() != nullptr && mi->owner() == hobj()) {
914
          ret++;
915
        }
916
      }
917
    }
918
  }
919
  return ret;
920
}
921

922
jvmtiError
923
JvmtiEnvBase::get_current_contended_monitor(JavaThread *calling_thread, JavaThread *java_thread,
924
                                            jobject *monitor_ptr, bool is_virtual) {
925
  Thread *current_thread = Thread::current();
926
  assert(java_thread->is_handshake_safe_for(current_thread),
927
         "call by myself or at handshake");
928
  if (!is_virtual && JvmtiEnvBase::is_cthread_with_continuation(java_thread)) {
929
    // Carrier thread with a mounted continuation case.
930
    // No contended monitor can be owned by carrier thread in this case.
931
    *monitor_ptr = nullptr;
932
    return JVMTI_ERROR_NONE;
933
  }
934
  oop obj = nullptr;
935
  // The ObjectMonitor* can't be async deflated since we are either
936
  // at a safepoint or the calling thread is operating on itself so
937
  // it cannot leave the underlying wait()/enter() call.
938
  ObjectMonitor *mon = java_thread->current_waiting_monitor();
939
  if (mon == nullptr) {
940
    // thread is not doing an Object.wait() call
941
    mon = java_thread->current_pending_monitor();
942
    if (mon != nullptr) {
943
      // The thread is trying to enter() an ObjectMonitor.
944
      obj = mon->object();
945
      assert(obj != nullptr, "ObjectMonitor should have a valid object!");
946
    }
947
  } else {
948
    // thread is doing an Object.wait() call
949
    oop thread_oop = get_vthread_or_thread_oop(java_thread);
950
    jint state = get_thread_or_vthread_state(thread_oop, java_thread);
951

952
    if (state & JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER) {
953
      // thread is re-entering the monitor in an Object.wait() call
954
      obj = mon->object();
955
      assert(obj != nullptr, "Object.wait() should have an object");
956
    }
957
  }
958

959
  if (obj == nullptr) {
960
    *monitor_ptr = nullptr;
961
  } else {
962
    HandleMark hm(current_thread);
963
    Handle     hobj(current_thread, obj);
964
    *monitor_ptr = jni_reference(calling_thread, hobj);
965
  }
966
  return JVMTI_ERROR_NONE;
967
}
968

969
jvmtiError
970
JvmtiEnvBase::get_owned_monitors(JavaThread *calling_thread, JavaThread* java_thread,
971
                                 GrowableArray<jvmtiMonitorStackDepthInfo*> *owned_monitors_list) {
972
  // Note:
973
  // calling_thread is the thread that requested the list of monitors for java_thread.
974
  // java_thread is the thread owning the monitors.
975
  // current_thread is the thread executing this code, can be a non-JavaThread (e.g. VM Thread).
976
  // And they all may be different threads.
977
  jvmtiError err = JVMTI_ERROR_NONE;
978
  Thread *current_thread = Thread::current();
979
  assert(java_thread->is_handshake_safe_for(current_thread),
980
         "call by myself or at handshake");
981

982
  if (JvmtiEnvBase::is_cthread_with_continuation(java_thread)) {
983
    // Carrier thread with a mounted continuation case.
984
    // No contended monitor can be owned by carrier thread in this case.
985
    return JVMTI_ERROR_NONE;
986
  }
987
  if (java_thread->has_last_Java_frame()) {
988
    ResourceMark rm(current_thread);
989
    HandleMark   hm(current_thread);
990
    RegisterMap  reg_map(java_thread,
991
                         RegisterMap::UpdateMap::include,
992
                         RegisterMap::ProcessFrames::include,
993
                         RegisterMap::WalkContinuation::skip);
994

995
    int depth = 0;
996
    for (javaVFrame *jvf = get_cthread_last_java_vframe(java_thread, &reg_map);
997
         jvf != nullptr; jvf = jvf->java_sender()) {
998
      if (MaxJavaStackTraceDepth == 0 || depth++ < MaxJavaStackTraceDepth) {  // check for stack too deep
999
        // add locked objects for this frame into list
1000
        err = get_locked_objects_in_frame(calling_thread, java_thread, jvf, owned_monitors_list, depth-1);
1001
        if (err != JVMTI_ERROR_NONE) {
1002
          return err;
1003
        }
1004
      }
1005
    }
1006
  }
1007

1008
  // Get off stack monitors. (e.g. acquired via jni MonitorEnter).
1009
  JvmtiMonitorClosure jmc(calling_thread, owned_monitors_list, this);
1010
  ObjectSynchronizer::owned_monitors_iterate(&jmc, java_thread);
1011
  err = jmc.error();
1012

1013
  return err;
1014
}
1015

1016
jvmtiError
1017
JvmtiEnvBase::get_owned_monitors(JavaThread* calling_thread, JavaThread* java_thread, javaVFrame* jvf,
1018
                                 GrowableArray<jvmtiMonitorStackDepthInfo*> *owned_monitors_list) {
1019
  jvmtiError err = JVMTI_ERROR_NONE;
1020
  Thread *current_thread = Thread::current();
1021
  assert(java_thread->is_handshake_safe_for(current_thread),
1022
         "call by myself or at handshake");
1023

1024
  int depth = 0;
1025
  for ( ; jvf != nullptr; jvf = jvf->java_sender()) {
1026
    if (MaxJavaStackTraceDepth == 0 || depth++ < MaxJavaStackTraceDepth) {  // check for stack too deep
1027
      // Add locked objects for this frame into list.
1028
      err = get_locked_objects_in_frame(calling_thread, java_thread, jvf, owned_monitors_list, depth - 1);
1029
      if (err != JVMTI_ERROR_NONE) {
1030
        return err;
1031
      }
1032
    }
1033
  }
1034

1035
  // Get off stack monitors. (e.g. acquired via jni MonitorEnter).
1036
  JvmtiMonitorClosure jmc(calling_thread, owned_monitors_list, this);
1037
  ObjectSynchronizer::owned_monitors_iterate(&jmc, java_thread);
1038
  err = jmc.error();
1039

1040
  return err;
1041
}
1042

1043
// Save JNI local handles for any objects that this frame owns.
1044
jvmtiError
1045
JvmtiEnvBase::get_locked_objects_in_frame(JavaThread* calling_thread, JavaThread* java_thread,
1046
                                 javaVFrame *jvf, GrowableArray<jvmtiMonitorStackDepthInfo*>* owned_monitors_list, jint stack_depth) {
1047
  jvmtiError err = JVMTI_ERROR_NONE;
1048
  Thread* current_thread = Thread::current();
1049
  ResourceMark rm(current_thread);
1050
  HandleMark   hm(current_thread);
1051

1052
  GrowableArray<MonitorInfo*>* mons = jvf->monitors();
1053
  if (mons->is_empty()) {
1054
    return err;  // this javaVFrame holds no monitors
1055
  }
1056

1057
  oop wait_obj = nullptr;
1058
  {
1059
    // The ObjectMonitor* can't be async deflated since we are either
1060
    // at a safepoint or the calling thread is operating on itself so
1061
    // it cannot leave the underlying wait() call.
1062
    // Save object of current wait() call (if any) for later comparison.
1063
    ObjectMonitor *mon = java_thread->current_waiting_monitor();
1064
    if (mon != nullptr) {
1065
      wait_obj = mon->object();
1066
    }
1067
  }
1068
  oop pending_obj = nullptr;
1069
  {
1070
    // The ObjectMonitor* can't be async deflated since we are either
1071
    // at a safepoint or the calling thread is operating on itself so
1072
    // it cannot leave the underlying enter() call.
1073
    // Save object of current enter() call (if any) for later comparison.
1074
    ObjectMonitor *mon = java_thread->current_pending_monitor();
1075
    if (mon != nullptr) {
1076
      pending_obj = mon->object();
1077
    }
1078
  }
1079

1080
  for (int i = 0; i < mons->length(); i++) {
1081
    MonitorInfo *mi = mons->at(i);
1082

1083
    if (mi->owner_is_scalar_replaced()) continue;
1084

1085
    oop obj = mi->owner();
1086
    if (obj == nullptr) {
1087
      // this monitor doesn't have an owning object so skip it
1088
      continue;
1089
    }
1090

1091
    if (wait_obj == obj) {
1092
      // the thread is waiting on this monitor so it isn't really owned
1093
      continue;
1094
    }
1095

1096
    if (pending_obj == obj) {
1097
      // the thread is pending on this monitor so it isn't really owned
1098
      continue;
1099
    }
1100

1101
    if (owned_monitors_list->length() > 0) {
1102
      // Our list has at least one object on it so we have to check
1103
      // for recursive object locking
1104
      bool found = false;
1105
      for (int j = 0; j < owned_monitors_list->length(); j++) {
1106
        jobject jobj = ((jvmtiMonitorStackDepthInfo*)owned_monitors_list->at(j))->monitor;
1107
        oop check = JNIHandles::resolve(jobj);
1108
        if (check == obj) {
1109
          found = true;  // we found the object
1110
          break;
1111
        }
1112
      }
1113

1114
      if (found) {
1115
        // already have this object so don't include it
1116
        continue;
1117
      }
1118
    }
1119

1120
    // add the owning object to our list
1121
    jvmtiMonitorStackDepthInfo *jmsdi;
1122
    err = allocate(sizeof(jvmtiMonitorStackDepthInfo), (unsigned char **)&jmsdi);
1123
    if (err != JVMTI_ERROR_NONE) {
1124
        return err;
1125
    }
1126
    Handle hobj(Thread::current(), obj);
1127
    jmsdi->monitor = jni_reference(calling_thread, hobj);
1128
    jmsdi->stack_depth = stack_depth;
1129
    owned_monitors_list->append(jmsdi);
1130
  }
1131

1132
  return err;
1133
}
1134

1135
jvmtiError
1136
JvmtiEnvBase::get_stack_trace(javaVFrame *jvf,
1137
                              jint start_depth, jint max_count,
1138
                              jvmtiFrameInfo* frame_buffer, jint* count_ptr) {
1139
  Thread *current_thread = Thread::current();
1140
  ResourceMark rm(current_thread);
1141
  HandleMark hm(current_thread);
1142
  int count = 0;
1143

1144
  if (start_depth != 0) {
1145
    if (start_depth > 0) {
1146
      for (int j = 0; j < start_depth && jvf != nullptr; j++) {
1147
        jvf = jvf->java_sender();
1148
      }
1149
      if (jvf == nullptr) {
1150
        // start_depth is deeper than the stack depth.
1151
        return JVMTI_ERROR_ILLEGAL_ARGUMENT;
1152
      }
1153
    } else { // start_depth < 0
1154
      // We are referencing the starting depth based on the oldest
1155
      // part of the stack.
1156
      // Optimize to limit the number of times that java_sender() is called.
1157
      javaVFrame *jvf_cursor = jvf;
1158
      javaVFrame *jvf_prev = nullptr;
1159
      javaVFrame *jvf_prev_prev = nullptr;
1160
      int j = 0;
1161
      while (jvf_cursor != nullptr) {
1162
        jvf_prev_prev = jvf_prev;
1163
        jvf_prev = jvf_cursor;
1164
        for (j = 0; j > start_depth && jvf_cursor != nullptr; j--) {
1165
          jvf_cursor = jvf_cursor->java_sender();
1166
        }
1167
      }
1168
      if (j == start_depth) {
1169
        // Previous pointer is exactly where we want to start.
1170
        jvf = jvf_prev;
1171
      } else {
1172
        // We need to back up further to get to the right place.
1173
        if (jvf_prev_prev == nullptr) {
1174
          // The -start_depth is greater than the stack depth.
1175
          return JVMTI_ERROR_ILLEGAL_ARGUMENT;
1176
        }
1177
        // j is now the number of frames on the stack starting with
1178
        // jvf_prev, we start from jvf_prev_prev and move older on
1179
        // the stack that many, and the result is -start_depth frames
1180
        // remaining.
1181
        jvf = jvf_prev_prev;
1182
        for (; j < 0; j++) {
1183
          jvf = jvf->java_sender();
1184
        }
1185
      }
1186
    }
1187
  }
1188
  for (; count < max_count && jvf != nullptr; count++) {
1189
    frame_buffer[count].method = jvf->method()->jmethod_id();
1190
    frame_buffer[count].location = (jvf->method()->is_native() ? -1 : jvf->bci());
1191
    jvf = jvf->java_sender();
1192
  }
1193
  *count_ptr = count;
1194
  return JVMTI_ERROR_NONE;
1195
}
1196

1197
jvmtiError
1198
JvmtiEnvBase::get_stack_trace(JavaThread *java_thread,
1199
                              jint start_depth, jint max_count,
1200
                              jvmtiFrameInfo* frame_buffer, jint* count_ptr) {
1201
  Thread *current_thread = Thread::current();
1202
  assert(SafepointSynchronize::is_at_safepoint() ||
1203
         java_thread->is_handshake_safe_for(current_thread),
1204
         "call by myself / at safepoint / at handshake");
1205
  int count = 0;
1206
  jvmtiError err = JVMTI_ERROR_NONE;
1207

1208
  if (java_thread->has_last_Java_frame()) {
1209
    RegisterMap reg_map(java_thread,
1210
                        RegisterMap::UpdateMap::include,
1211
                        RegisterMap::ProcessFrames::skip,
1212
                        RegisterMap::WalkContinuation::skip);
1213
    ResourceMark rm(current_thread);
1214
    javaVFrame *jvf = get_cthread_last_java_vframe(java_thread, &reg_map);
1215

1216
    err = get_stack_trace(jvf, start_depth, max_count, frame_buffer, count_ptr);
1217
  } else {
1218
    *count_ptr = 0;
1219
    if (start_depth != 0) {
1220
      // no frames and there is a starting depth
1221
      err = JVMTI_ERROR_ILLEGAL_ARGUMENT;
1222
    }
1223
  }
1224
  return err;
1225
}
1226

1227
jint
1228
JvmtiEnvBase::get_frame_count(javaVFrame *jvf) {
1229
  int count = 0;
1230

1231
  while (jvf != nullptr) {
1232
    jvf = jvf->java_sender();
1233
    count++;
1234
  }
1235
  return count;
1236
}
1237

1238
jvmtiError
1239
JvmtiEnvBase::get_frame_count(JavaThread* jt, jint *count_ptr) {
1240
  Thread *current_thread = Thread::current();
1241
  assert(current_thread == jt ||
1242
         SafepointSynchronize::is_at_safepoint() ||
1243
         jt->is_handshake_safe_for(current_thread),
1244
         "call by myself / at safepoint / at handshake");
1245

1246
  if (!jt->has_last_Java_frame()) { // no Java frames
1247
    *count_ptr = 0;
1248
  } else {
1249
    ResourceMark rm(current_thread);
1250
    RegisterMap reg_map(jt,
1251
                        RegisterMap::UpdateMap::include,
1252
                        RegisterMap::ProcessFrames::include,
1253
                        RegisterMap::WalkContinuation::skip);
1254
    javaVFrame *jvf = get_cthread_last_java_vframe(jt, &reg_map);
1255

1256
    *count_ptr = get_frame_count(jvf);
1257
  }
1258
  return JVMTI_ERROR_NONE;
1259
}
1260

1261
jvmtiError
1262
JvmtiEnvBase::get_frame_count(oop vthread_oop, jint *count_ptr) {
1263
  Thread *current_thread = Thread::current();
1264
  ResourceMark rm(current_thread);
1265
  javaVFrame *jvf = JvmtiEnvBase::get_vthread_jvf(vthread_oop);
1266

1267
  *count_ptr = get_frame_count(jvf);
1268
  return JVMTI_ERROR_NONE;
1269
}
1270

1271
jvmtiError
1272
JvmtiEnvBase::get_frame_location(javaVFrame* jvf, jint depth,
1273
                                 jmethodID* method_ptr, jlocation* location_ptr) {
1274
  int cur_depth = 0;
1275

1276
  while (jvf != nullptr && cur_depth < depth) {
1277
    jvf = jvf->java_sender();
1278
    cur_depth++;
1279
  }
1280
  assert(depth >= cur_depth, "ran out of frames too soon");
1281
  if (jvf == nullptr) {
1282
    return JVMTI_ERROR_NO_MORE_FRAMES;
1283
  }
1284
  Method* method = jvf->method();
1285
  if (method->is_native()) {
1286
    *location_ptr = -1;
1287
  } else {
1288
    *location_ptr = jvf->bci();
1289
  }
1290
  *method_ptr = method->jmethod_id();
1291
  return JVMTI_ERROR_NONE;
1292
}
1293

1294
jvmtiError
1295
JvmtiEnvBase::get_frame_location(JavaThread *java_thread, jint depth,
1296
                                 jmethodID* method_ptr, jlocation* location_ptr) {
1297
  Thread* current = Thread::current();
1298
  assert(java_thread->is_handshake_safe_for(current),
1299
         "call by myself or at handshake");
1300
  if (!java_thread->has_last_Java_frame()) {
1301
    return JVMTI_ERROR_NO_MORE_FRAMES;
1302
  }
1303
  ResourceMark rm(current);
1304
  HandleMark hm(current);
1305
  RegisterMap reg_map(java_thread,
1306
                      RegisterMap::UpdateMap::include,
1307
                      RegisterMap::ProcessFrames::skip,
1308
                      RegisterMap::WalkContinuation::include);
1309
  javaVFrame* jvf = JvmtiEnvBase::get_cthread_last_java_vframe(java_thread, &reg_map);
1310

1311
  return get_frame_location(jvf, depth, method_ptr, location_ptr);
1312
}
1313

1314
jvmtiError
1315
JvmtiEnvBase::get_frame_location(oop vthread_oop, jint depth,
1316
                                 jmethodID* method_ptr, jlocation* location_ptr) {
1317
  Thread* current = Thread::current();
1318
  ResourceMark rm(current);
1319
  HandleMark hm(current);
1320
  javaVFrame *jvf = JvmtiEnvBase::get_vthread_jvf(vthread_oop);
1321

1322
  return get_frame_location(jvf, depth, method_ptr, location_ptr);
1323
}
1324

1325
jvmtiError
1326
JvmtiEnvBase::set_frame_pop(JvmtiThreadState* state, javaVFrame* jvf, jint depth) {
1327
  for (int d = 0; jvf != nullptr && d < depth; d++) {
1328
    jvf = jvf->java_sender();
1329
  }
1330
  if (jvf == nullptr) {
1331
    return JVMTI_ERROR_NO_MORE_FRAMES;
1332
  }
1333
  if (jvf->method()->is_native()) {
1334
    return JVMTI_ERROR_OPAQUE_FRAME;
1335
  }
1336
  assert(jvf->frame_pointer() != nullptr, "frame pointer mustn't be null");
1337
  int frame_number = (int)get_frame_count(jvf);
1338
  state->env_thread_state((JvmtiEnvBase*)this)->set_frame_pop(frame_number);
1339
  return JVMTI_ERROR_NONE;
1340
}
1341

1342
bool
1343
JvmtiEnvBase::is_cthread_with_mounted_vthread(JavaThread* jt) {
1344
  oop thread_oop = jt->threadObj();
1345
  assert(thread_oop != nullptr, "sanity check");
1346
  oop mounted_vt = jt->jvmti_vthread();
1347

1348
  return mounted_vt != nullptr && mounted_vt != thread_oop;
1349
}
1350

1351
bool
1352
JvmtiEnvBase::is_cthread_with_continuation(JavaThread* jt) {
1353
  const ContinuationEntry* cont_entry = nullptr;
1354
  if (jt->has_last_Java_frame()) {
1355
    cont_entry = jt->vthread_continuation();
1356
  }
1357
  return cont_entry != nullptr && is_cthread_with_mounted_vthread(jt);
1358
}
1359

1360
// Check if VirtualThread or BoundVirtualThread is suspended.
1361
bool
1362
JvmtiEnvBase::is_vthread_suspended(oop vt_oop, JavaThread* jt) {
1363
  bool suspended = false;
1364
  if (java_lang_VirtualThread::is_instance(vt_oop)) {
1365
    suspended = JvmtiVTSuspender::is_vthread_suspended(vt_oop);
1366
  }
1367
  if (vt_oop->is_a(vmClasses::BoundVirtualThread_klass())) {
1368
    suspended = jt->is_suspended();
1369
  }
1370
  return suspended;
1371
}
1372

1373
// If (thread == null) then return current thread object.
1374
// Otherwise return JNIHandles::resolve_external_guard(thread).
1375
oop
1376
JvmtiEnvBase::current_thread_obj_or_resolve_external_guard(jthread thread) {
1377
  oop thread_obj = JNIHandles::resolve_external_guard(thread);
1378
  if (thread == nullptr) {
1379
    thread_obj = get_vthread_or_thread_oop(JavaThread::current());
1380
  }
1381
  return thread_obj;
1382
}
1383

1384
jvmtiError
1385
JvmtiEnvBase::get_threadOop_and_JavaThread(ThreadsList* t_list, jthread thread, JavaThread* cur_thread,
1386
                                           JavaThread** jt_pp, oop* thread_oop_p) {
1387
  JavaThread* java_thread = nullptr;
1388
  oop thread_oop = nullptr;
1389

1390
  if (thread == nullptr) {
1391
    if (cur_thread == nullptr) { // cur_thread can be null when called from a VM_op
1392
      return JVMTI_ERROR_INVALID_THREAD;
1393
    }
1394
    java_thread = cur_thread;
1395
    thread_oop = get_vthread_or_thread_oop(java_thread);
1396
    if (thread_oop == nullptr || !thread_oop->is_a(vmClasses::Thread_klass())) {
1397
      return JVMTI_ERROR_INVALID_THREAD;
1398
    }
1399
  } else {
1400
    jvmtiError err = JvmtiExport::cv_external_thread_to_JavaThread(t_list, thread, &java_thread, &thread_oop);
1401
    if (err != JVMTI_ERROR_NONE) {
1402
      // We got an error code so we don't have a JavaThread*, but only return
1403
      // an error from here if we didn't get a valid thread_oop. In a vthread case
1404
      // the cv_external_thread_to_JavaThread is expected to correctly set the
1405
      // thread_oop and return JVMTI_ERROR_INVALID_THREAD which we ignore here.
1406
      if (thread_oop == nullptr || err != JVMTI_ERROR_INVALID_THREAD) {
1407
        *thread_oop_p = thread_oop;
1408
        return err;
1409
      }
1410
    }
1411
    if (java_thread == nullptr && java_lang_VirtualThread::is_instance(thread_oop)) {
1412
      java_thread = get_JavaThread_or_null(thread_oop);
1413
    }
1414
  }
1415
  *jt_pp = java_thread;
1416
  *thread_oop_p = thread_oop;
1417
  if (java_lang_VirtualThread::is_instance(thread_oop) &&
1418
      !JvmtiEnvBase::is_vthread_alive(thread_oop)) {
1419
    return JVMTI_ERROR_THREAD_NOT_ALIVE;
1420
  }
1421
  return JVMTI_ERROR_NONE;
1422
}
1423

1424
// Check for JVMTI_ERROR_NOT_SUSPENDED and JVMTI_ERROR_OPAQUE_FRAME errors.
1425
// Used in PopFrame and ForceEarlyReturn implementations.
1426
jvmtiError
1427
JvmtiEnvBase::check_non_suspended_or_opaque_frame(JavaThread* jt, oop thr_obj, bool self) {
1428
  bool is_virtual = thr_obj != nullptr && thr_obj->is_a(vmClasses::BaseVirtualThread_klass());
1429

1430
  if (is_virtual) {
1431
    if (!is_JavaThread_current(jt, thr_obj)) {
1432
      if (!is_vthread_suspended(thr_obj, jt)) {
1433
        return JVMTI_ERROR_THREAD_NOT_SUSPENDED;
1434
      }
1435
      if (jt == nullptr) { // unmounted virtual thread
1436
        return JVMTI_ERROR_OPAQUE_FRAME;
1437
      }
1438
    }
1439
  } else { // platform thread
1440
    if (!self && !jt->is_suspended() &&
1441
        !jt->is_carrier_thread_suspended()) {
1442
      return JVMTI_ERROR_THREAD_NOT_SUSPENDED;
1443
    }
1444
  }
1445
  return JVMTI_ERROR_NONE;
1446
}
1447

1448
jvmtiError
1449
JvmtiEnvBase::get_object_monitor_usage(JavaThread* calling_thread, jobject object, jvmtiMonitorUsage* info_ptr) {
1450
  assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
1451
  Thread* current_thread = VMThread::vm_thread();
1452
  assert(current_thread == Thread::current(), "must be");
1453

1454
  HandleMark hm(current_thread);
1455
  Handle hobj;
1456

1457
  // Check arguments
1458
  {
1459
    oop mirror = JNIHandles::resolve_external_guard(object);
1460
    NULL_CHECK(mirror, JVMTI_ERROR_INVALID_OBJECT);
1461
    NULL_CHECK(info_ptr, JVMTI_ERROR_NULL_POINTER);
1462

1463
    hobj = Handle(current_thread, mirror);
1464
  }
1465

1466
  ThreadsListHandle tlh(current_thread);
1467
  JavaThread *owning_thread = nullptr;
1468
  ObjectMonitor *mon = nullptr;
1469
  jvmtiMonitorUsage ret = {
1470
      nullptr, 0, 0, nullptr, 0, nullptr
1471
  };
1472

1473
  uint32_t debug_bits = 0;
1474
  // first derive the object's owner and entry_count (if any)
1475
  owning_thread = ObjectSynchronizer::get_lock_owner(tlh.list(), hobj);
1476
  if (owning_thread != nullptr) {
1477
    oop thread_oop = get_vthread_or_thread_oop(owning_thread);
1478
    bool is_virtual = thread_oop->is_a(vmClasses::BaseVirtualThread_klass());
1479
    if (is_virtual) {
1480
      thread_oop = nullptr;
1481
    }
1482
    Handle th(current_thread, thread_oop);
1483
    ret.owner = (jthread)jni_reference(calling_thread, th);
1484

1485
    // The recursions field of a monitor does not reflect recursions
1486
    // as lightweight locks before inflating the monitor are not included.
1487
    // We have to count the number of recursive monitor entries the hard way.
1488
    // We pass a handle to survive any GCs along the way.
1489
    ret.entry_count = is_virtual ? 0 : count_locked_objects(owning_thread, hobj);
1490
  }
1491
  // implied else: entry_count == 0
1492

1493
  jint nWant = 0, nWait = 0;
1494
  markWord mark = hobj->mark();
1495
  ResourceMark rm(current_thread);
1496
  GrowableArray<JavaThread*>* wantList = nullptr;
1497

1498
  if (mark.has_monitor()) {
1499
    mon = mark.monitor();
1500
    assert(mon != nullptr, "must have monitor");
1501
    // this object has a heavyweight monitor
1502
    nWant = mon->contentions(); // # of threads contending for monitor entry, but not re-entry
1503
    nWait = mon->waiters();     // # of threads waiting for notification,
1504
                                // or to re-enter monitor, in Object.wait()
1505

1506
    // Get the actual set of threads trying to enter, or re-enter, the monitor.
1507
    wantList = Threads::get_pending_threads(tlh.list(), nWant + nWait, (address)mon);
1508
    nWant = wantList->length();
1509
  } else {
1510
    // this object has a lightweight monitor
1511
  }
1512

1513
  jint skipped = 0;
1514
  if (mon != nullptr) {
1515
    // Robustness: the actual waiting list can be smaller.
1516
    // The nWait count we got from the mon->waiters() may include the re-entering
1517
    // the monitor threads after being notified. Here we are correcting the actual
1518
    // number of the waiting threads by excluding those re-entering the monitor.
1519
    nWait = 0;
1520
    for (ObjectWaiter* waiter = mon->first_waiter();
1521
         waiter != nullptr && (nWait == 0 || waiter != mon->first_waiter());
1522
         waiter = mon->next_waiter(waiter)) {
1523
      JavaThread *w = mon->thread_of_waiter(waiter);
1524
      oop thread_oop = get_vthread_or_thread_oop(w);
1525
      if (thread_oop->is_a(vmClasses::BaseVirtualThread_klass())) {
1526
        skipped++;
1527
      }
1528
      nWait++;
1529
    }
1530
  }
1531
  ret.waiter_count = nWant;
1532
  ret.notify_waiter_count = nWait - skipped;
1533

1534
  // Allocate memory for heavyweight and lightweight monitor.
1535
  jvmtiError err;
1536
  err = allocate(ret.waiter_count * sizeof(jthread *), (unsigned char**)&ret.waiters);
1537
  if (err != JVMTI_ERROR_NONE) {
1538
    return err;
1539
  }
1540
  err = allocate(ret.notify_waiter_count * sizeof(jthread *),
1541
                 (unsigned char**)&ret.notify_waiters);
1542
  if (err != JVMTI_ERROR_NONE) {
1543
    deallocate((unsigned char*)ret.waiters);
1544
    return err;
1545
  }
1546

1547
  // now derive the rest of the fields
1548
  if (mon != nullptr) {
1549
    // this object has a heavyweight monitor
1550

1551
    // null out memory for robustness
1552
    if (ret.waiters != nullptr) {
1553
      memset(ret.waiters, 0, ret.waiter_count * sizeof(jthread *));
1554
    }
1555
    if (ret.notify_waiters != nullptr) {
1556
      memset(ret.notify_waiters, 0, ret.notify_waiter_count * sizeof(jthread *));
1557
    }
1558

1559
    if (ret.waiter_count > 0) { // we have contending threads waiting to enter/re-enter the monitor
1560
      // identify threads waiting to enter and re-enter the monitor
1561
      // get_pending_threads returns only java thread so we do not need to
1562
      // check for non java threads.
1563
      for (int i = 0; i < nWant; i++) {
1564
        JavaThread *pending_thread = wantList->at(i);
1565
        Handle th(current_thread, get_vthread_or_thread_oop(pending_thread));
1566
        ret.waiters[i] = (jthread)jni_reference(calling_thread, th);
1567
      }
1568
    }
1569
    if (ret.notify_waiter_count > 0) { // we have threads waiting to be notified in Object.wait()
1570
      ObjectWaiter *waiter = mon->first_waiter();
1571
      jint skipped = 0;
1572
      for (int i = 0; i < nWait; i++) {
1573
        JavaThread *w = mon->thread_of_waiter(waiter);
1574
        oop thread_oop = get_vthread_or_thread_oop(w);
1575
        bool is_virtual = thread_oop->is_a(vmClasses::BaseVirtualThread_klass());
1576
        assert(w != nullptr, "sanity check");
1577
        if (is_virtual) {
1578
          skipped++;
1579
        } else {
1580
          // If the thread was found on the ObjectWaiter list, then
1581
          // it has not been notified.
1582
          Handle th(current_thread, get_vthread_or_thread_oop(w));
1583
          ret.notify_waiters[i - skipped] = (jthread)jni_reference(calling_thread, th);
1584
        }
1585
        waiter = mon->next_waiter(waiter);
1586
      }
1587
    }
1588
  } else {
1589
    // this object has a lightweight monitor and we have nothing more
1590
    // to do here because the defaults are just fine.
1591
  }
1592

1593
  // we don't update return parameter unless everything worked
1594
  *info_ptr = ret;
1595

1596
  return JVMTI_ERROR_NONE;
1597
}
1598

1599
jvmtiError
1600
JvmtiEnvBase::check_thread_list(jint count, const jthread* list) {
1601
  if (list == nullptr && count != 0) {
1602
    return JVMTI_ERROR_NULL_POINTER;
1603
  }
1604
  for (int i = 0; i < count; i++) {
1605
    jthread thread = list[i];
1606
    oop thread_oop = JNIHandles::resolve_external_guard(thread);
1607
    if (thread_oop == nullptr || !thread_oop->is_a(vmClasses::BaseVirtualThread_klass())) {
1608
      return JVMTI_ERROR_INVALID_THREAD;
1609
    }
1610
  }
1611
  return JVMTI_ERROR_NONE;
1612
}
1613

1614
bool
1615
JvmtiEnvBase::is_in_thread_list(jint count, const jthread* list, oop jt_oop) {
1616
  for (int idx = 0; idx < count; idx++) {
1617
    jthread thread = list[idx];
1618
    oop thread_oop = JNIHandles::resolve_external_guard(thread);
1619
    if (thread_oop == jt_oop) {
1620
      return true;
1621
    }
1622
  }
1623
  return false;
1624
}
1625

1626
class VM_SetNotifyJvmtiEventsMode : public VM_Operation {
1627
private:
1628
  bool _enable;
1629

1630
  static void correct_jvmti_thread_state(JavaThread* jt) {
1631
    oop  ct_oop = jt->threadObj();
1632
    oop  vt_oop = jt->vthread();
1633
    JvmtiThreadState* jt_state = jt->jvmti_thread_state();
1634
    JvmtiThreadState* ct_state = java_lang_Thread::jvmti_thread_state(jt->threadObj());
1635
    JvmtiThreadState* vt_state = vt_oop != nullptr ? java_lang_Thread::jvmti_thread_state(vt_oop) : nullptr;
1636
    bool virt = vt_oop != nullptr && java_lang_VirtualThread::is_instance(vt_oop);
1637

1638
    // Correct jt->jvmti_thread_state() and jt->jvmti_vthread().
1639
    // It was not maintained while notifyJvmti was disabled.
1640
    if (virt) {
1641
      jt->set_jvmti_thread_state(nullptr);  // reset jt->jvmti_thread_state()
1642
      jt->set_jvmti_vthread(vt_oop);        // restore jt->jvmti_vthread()
1643
    } else {
1644
      jt->set_jvmti_thread_state(ct_state); // restore jt->jvmti_thread_state()
1645
      jt->set_jvmti_vthread(ct_oop);        // restore jt->jvmti_vthread()
1646
    }
1647
  }
1648

1649
  // This function is called only if _enable == true.
1650
  // Iterates over all JavaThread's, restores jt->jvmti_thread_state() and
1651
  // jt->jvmti_vthread() for VTMS transition protocol.
1652
  void correct_jvmti_thread_states() {
1653
    for (JavaThread* jt : ThreadsListHandle()) {
1654
      if (jt->is_in_VTMS_transition()) {
1655
        jt->set_VTMS_transition_mark(true);
1656
        continue; // no need in JvmtiThreadState correction below if in transition
1657
      }
1658
      correct_jvmti_thread_state(jt);
1659
    }
1660
  }
1661

1662
public:
1663
  VMOp_Type type() const { return VMOp_SetNotifyJvmtiEventsMode; }
1664
  bool allow_nested_vm_operations() const { return false; }
1665
  VM_SetNotifyJvmtiEventsMode(bool enable) : _enable(enable) {
1666
  }
1667

1668
  void doit() {
1669
    if (_enable) {
1670
      correct_jvmti_thread_states();
1671
    }
1672
    JvmtiVTMSTransitionDisabler::set_VTMS_notify_jvmti_events(_enable);
1673
  }
1674
};
1675

1676
// This function is to support agents loaded into running VM.
1677
// Must be called in thread-in-native mode.
1678
bool
1679
JvmtiEnvBase::enable_virtual_threads_notify_jvmti() {
1680
  if (!Continuations::enabled()) {
1681
    return false;
1682
  }
1683
  if (JvmtiVTMSTransitionDisabler::VTMS_notify_jvmti_events()) {
1684
    return false; // already enabled
1685
  }
1686
  VM_SetNotifyJvmtiEventsMode op(true);
1687
  VMThread::execute(&op);
1688
  return true;
1689
}
1690

1691
// This function is used in WhiteBox, only needed to test the function above.
1692
// It is unsafe to use this function when virtual threads are executed.
1693
// Must be called in thread-in-native mode.
1694
bool
1695
JvmtiEnvBase::disable_virtual_threads_notify_jvmti() {
1696
  if (!Continuations::enabled()) {
1697
    return false;
1698
  }
1699
  if (!JvmtiVTMSTransitionDisabler::VTMS_notify_jvmti_events()) {
1700
    return false; // already disabled
1701
  }
1702
  JvmtiVTMSTransitionDisabler disabler(true); // ensure there are no other disablers
1703
  VM_SetNotifyJvmtiEventsMode op(false);
1704
  VMThread::execute(&op);
1705
  return true;
1706
}
1707

1708
// java_thread - protected by ThreadsListHandle
1709
jvmtiError
1710
JvmtiEnvBase::suspend_thread(oop thread_oop, JavaThread* java_thread, bool single_suspend,
1711
                             int* need_safepoint_p) {
1712
  JavaThread* current = JavaThread::current();
1713
  HandleMark hm(current);
1714
  Handle thread_h(current, thread_oop);
1715
  bool is_virtual = java_lang_VirtualThread::is_instance(thread_h());
1716

1717
  if (is_virtual) {
1718
    if (single_suspend) {
1719
      if (JvmtiVTSuspender::is_vthread_suspended(thread_h())) {
1720
        return JVMTI_ERROR_THREAD_SUSPENDED;
1721
      }
1722
      JvmtiVTSuspender::register_vthread_suspend(thread_h());
1723
      // Check if virtual thread is mounted and there is a java_thread.
1724
      // A non-null java_thread is always passed in the !single_suspend case.
1725
      oop carrier_thread = java_lang_VirtualThread::carrier_thread(thread_h());
1726
      java_thread = carrier_thread == nullptr ? nullptr : java_lang_Thread::thread(carrier_thread);
1727
    }
1728
    // The java_thread can be still blocked in VTMS transition after a previous JVMTI resume call.
1729
    // There is no need to suspend the java_thread in this case. After vthread unblocking,
1730
    // it will check for ext_suspend request and suspend itself if necessary.
1731
    if (java_thread == nullptr || java_thread->is_suspended()) {
1732
      // We are done if the virtual thread is unmounted or
1733
      // the java_thread is externally suspended.
1734
      return JVMTI_ERROR_NONE;
1735
    }
1736
    // The virtual thread is mounted: suspend the java_thread.
1737
  }
1738
  // Don't allow hidden thread suspend request.
1739
  if (java_thread->is_hidden_from_external_view()) {
1740
    return JVMTI_ERROR_NONE;
1741
  }
1742
  bool is_thread_carrying = is_thread_carrying_vthread(java_thread, thread_h());
1743

1744
  // A case of non-virtual thread.
1745
  if (!is_virtual) {
1746
    // Thread.suspend() is used in some tests. It sets jt->is_suspended() only.
1747
    if (java_thread->is_carrier_thread_suspended() ||
1748
        (!is_thread_carrying && java_thread->is_suspended())) {
1749
      return JVMTI_ERROR_THREAD_SUSPENDED;
1750
    }
1751
    java_thread->set_carrier_thread_suspended();
1752
  }
1753
  assert(!java_thread->is_in_VTMS_transition(), "sanity check");
1754

1755
  assert(!single_suspend || (!is_virtual && java_thread->is_carrier_thread_suspended()) ||
1756
          (is_virtual && JvmtiVTSuspender::is_vthread_suspended(thread_h())),
1757
         "sanity check");
1758

1759
  // An attempt to handshake-suspend a thread carrying a virtual thread will result in
1760
  // suspension of mounted virtual thread. So, we just mark it as suspended
1761
  // and it will be actually suspended at virtual thread unmount transition.
1762
  if (!is_thread_carrying) {
1763
    assert(thread_h() != nullptr, "sanity check");
1764
    assert(single_suspend || thread_h()->is_a(vmClasses::BaseVirtualThread_klass()),
1765
           "SuspendAllVirtualThreads should never suspend non-virtual threads");
1766
    // Case of mounted virtual or attached carrier thread.
1767
    if (!JvmtiSuspendControl::suspend(java_thread)) {
1768
      // Thread is already suspended or in process of exiting.
1769
      if (java_thread->is_exiting()) {
1770
        // The thread was in the process of exiting.
1771
        return JVMTI_ERROR_THREAD_NOT_ALIVE;
1772
      }
1773
      return JVMTI_ERROR_THREAD_SUSPENDED;
1774
    }
1775
  }
1776
  return JVMTI_ERROR_NONE;
1777
}
1778

1779
// java_thread - protected by ThreadsListHandle
1780
jvmtiError
1781
JvmtiEnvBase::resume_thread(oop thread_oop, JavaThread* java_thread, bool single_resume) {
1782
  JavaThread* current = JavaThread::current();
1783
  HandleMark hm(current);
1784
  Handle thread_h(current, thread_oop);
1785
  bool is_virtual = java_lang_VirtualThread::is_instance(thread_h());
1786

1787
  if (is_virtual) {
1788
    if (single_resume) {
1789
      if (!JvmtiVTSuspender::is_vthread_suspended(thread_h())) {
1790
        return JVMTI_ERROR_THREAD_NOT_SUSPENDED;
1791
      }
1792
      JvmtiVTSuspender::register_vthread_resume(thread_h());
1793
      // Check if virtual thread is mounted and there is a java_thread.
1794
      // A non-null java_thread is always passed in the !single_resume case.
1795
      oop carrier_thread = java_lang_VirtualThread::carrier_thread(thread_h());
1796
      java_thread = carrier_thread == nullptr ? nullptr : java_lang_Thread::thread(carrier_thread);
1797
    }
1798
    // The java_thread can be still blocked in VTMS transition after a previous JVMTI suspend call.
1799
    // There is no need to resume the java_thread in this case. After vthread unblocking,
1800
    // it will check for is_vthread_suspended request and remain resumed if necessary.
1801
    if (java_thread == nullptr || !java_thread->is_suspended()) {
1802
      // We are done if the virtual thread is unmounted or
1803
      // the java_thread is not externally suspended.
1804
      return JVMTI_ERROR_NONE;
1805
    }
1806
    // The virtual thread is mounted and java_thread is supended: resume the java_thread.
1807
  }
1808
  // Don't allow hidden thread resume request.
1809
  if (java_thread->is_hidden_from_external_view()) {
1810
    return JVMTI_ERROR_NONE;
1811
  }
1812
  bool is_thread_carrying = is_thread_carrying_vthread(java_thread, thread_h());
1813

1814
  // A case of a non-virtual thread.
1815
  if (!is_virtual) {
1816
    if (!java_thread->is_carrier_thread_suspended() &&
1817
        (is_thread_carrying || !java_thread->is_suspended())) {
1818
      return JVMTI_ERROR_THREAD_NOT_SUSPENDED;
1819
    }
1820
    java_thread->clear_carrier_thread_suspended();
1821
  }
1822
  assert(!java_thread->is_in_VTMS_transition(), "sanity check");
1823

1824
  if (!is_thread_carrying) {
1825
    assert(thread_h() != nullptr, "sanity check");
1826
    assert(single_resume || thread_h()->is_a(vmClasses::BaseVirtualThread_klass()),
1827
           "ResumeAllVirtualThreads should never resume non-virtual threads");
1828
    if (java_thread->is_suspended()) {
1829
      if (!JvmtiSuspendControl::resume(java_thread)) {
1830
        return JVMTI_ERROR_THREAD_NOT_SUSPENDED;
1831
      }
1832
    }
1833
  }
1834
  return JVMTI_ERROR_NONE;
1835
}
1836

1837
ResourceTracker::ResourceTracker(JvmtiEnv* env) {
1838
  _env = env;
1839
  _allocations = new (mtServiceability) GrowableArray<unsigned char*>(20, mtServiceability);
1840
  _failed = false;
1841
}
1842
ResourceTracker::~ResourceTracker() {
1843
  if (_failed) {
1844
    for (int i=0; i<_allocations->length(); i++) {
1845
      _env->deallocate(_allocations->at(i));
1846
    }
1847
  }
1848
  delete _allocations;
1849
}
1850

1851
jvmtiError ResourceTracker::allocate(jlong size, unsigned char** mem_ptr) {
1852
  unsigned char *ptr;
1853
  jvmtiError err = _env->allocate(size, &ptr);
1854
  if (err == JVMTI_ERROR_NONE) {
1855
    _allocations->append(ptr);
1856
    *mem_ptr = ptr;
1857
  } else {
1858
    *mem_ptr = nullptr;
1859
    _failed = true;
1860
  }
1861
  return err;
1862
 }
1863

1864
unsigned char* ResourceTracker::allocate(jlong size) {
1865
  unsigned char* ptr;
1866
  allocate(size, &ptr);
1867
  return ptr;
1868
}
1869

1870
char* ResourceTracker::strdup(const char* str) {
1871
  char *dup_str = (char*)allocate(strlen(str)+1);
1872
  if (dup_str != nullptr) {
1873
    strcpy(dup_str, str);
1874
  }
1875
  return dup_str;
1876
}
1877

1878
struct StackInfoNode {
1879
  struct StackInfoNode *next;
1880
  jvmtiStackInfo info;
1881
};
1882

1883
// Create a jvmtiStackInfo inside a linked list node and create a
1884
// buffer for the frame information, both allocated as resource objects.
1885
// Fill in both the jvmtiStackInfo and the jvmtiFrameInfo.
1886
// Note that either or both of thr and thread_oop
1887
// may be null if the thread is new or has exited.
1888
void
1889
MultipleStackTracesCollector::fill_frames(jthread jt, JavaThread *thr, oop thread_oop) {
1890
#ifdef ASSERT
1891
  Thread *current_thread = Thread::current();
1892
  assert(SafepointSynchronize::is_at_safepoint() ||
1893
         thr == nullptr ||
1894
         thr->is_handshake_safe_for(current_thread),
1895
         "unmounted virtual thread / call by myself / at safepoint / at handshake");
1896
#endif
1897

1898
  jint state = 0;
1899
  struct StackInfoNode *node = NEW_RESOURCE_OBJ(struct StackInfoNode);
1900
  jvmtiStackInfo *infop = &(node->info);
1901

1902
  node->next = head();
1903
  set_head(node);
1904
  infop->frame_count = 0;
1905
  infop->frame_buffer = nullptr;
1906
  infop->thread = jt;
1907

1908
  if (java_lang_VirtualThread::is_instance(thread_oop)) {
1909
    state = JvmtiEnvBase::get_vthread_state(thread_oop, thr);
1910

1911
    if ((state & JVMTI_THREAD_STATE_ALIVE) != 0) {
1912
      javaVFrame *jvf = JvmtiEnvBase::get_vthread_jvf(thread_oop);
1913
      infop->frame_buffer = NEW_RESOURCE_ARRAY(jvmtiFrameInfo, max_frame_count());
1914
      _result = env()->get_stack_trace(jvf, 0, max_frame_count(),
1915
                                       infop->frame_buffer, &(infop->frame_count));
1916
    }
1917
  } else {
1918
    state = JvmtiEnvBase::get_thread_state(thread_oop, thr);
1919
    if (thr != nullptr && (state & JVMTI_THREAD_STATE_ALIVE) != 0) {
1920
      infop->frame_buffer = NEW_RESOURCE_ARRAY(jvmtiFrameInfo, max_frame_count());
1921
      _result = env()->get_stack_trace(thr, 0, max_frame_count(),
1922
                                       infop->frame_buffer, &(infop->frame_count));
1923
    }
1924
  }
1925
  _frame_count_total += infop->frame_count;
1926
  infop->state = state;
1927
}
1928

1929
// Based on the stack information in the linked list, allocate memory
1930
// block to return and fill it from the info in the linked list.
1931
void
1932
MultipleStackTracesCollector::allocate_and_fill_stacks(jint thread_count) {
1933
  // do I need to worry about alignment issues?
1934
  jlong alloc_size =  thread_count       * sizeof(jvmtiStackInfo)
1935
                    + _frame_count_total * sizeof(jvmtiFrameInfo);
1936
  env()->allocate(alloc_size, (unsigned char **)&_stack_info);
1937

1938
  // pointers to move through the newly allocated space as it is filled in
1939
  jvmtiStackInfo *si = _stack_info + thread_count;      // bottom of stack info
1940
  jvmtiFrameInfo *fi = (jvmtiFrameInfo *)si;            // is the top of frame info
1941

1942
  // copy information in resource area into allocated buffer
1943
  // insert stack info backwards since linked list is backwards
1944
  // insert frame info forwards
1945
  // walk the StackInfoNodes
1946
  for (struct StackInfoNode *sin = head(); sin != nullptr; sin = sin->next) {
1947
    jint frame_count = sin->info.frame_count;
1948
    size_t frames_size = frame_count * sizeof(jvmtiFrameInfo);
1949
    --si;
1950
    memcpy(si, &(sin->info), sizeof(jvmtiStackInfo));
1951
    if (frames_size == 0) {
1952
      si->frame_buffer = nullptr;
1953
    } else {
1954
      memcpy(fi, sin->info.frame_buffer, frames_size);
1955
      si->frame_buffer = fi;  // point to the new allocated copy of the frames
1956
      fi += frame_count;
1957
    }
1958
  }
1959
  assert(si == _stack_info, "the last copied stack info must be the first record");
1960
  assert((unsigned char *)fi == ((unsigned char *)_stack_info) + alloc_size,
1961
         "the last copied frame info must be the last record");
1962
}
1963

1964
// AdapterClosure is to make use of JvmtiUnitedHandshakeClosure objects from
1965
// Handshake::execute() which is unaware of the do_vthread() member functions.
1966
class AdapterClosure : public HandshakeClosure {
1967
  JvmtiUnitedHandshakeClosure* _hs_cl;
1968
  Handle _target_h;
1969

1970
 public:
1971
  AdapterClosure(JvmtiUnitedHandshakeClosure* hs_cl, Handle target_h)
1972
      : HandshakeClosure(hs_cl->name()), _hs_cl(hs_cl), _target_h(target_h) {}
1973

1974
  virtual void do_thread(Thread* target) {
1975
    if (java_lang_VirtualThread::is_instance(_target_h())) {
1976
      _hs_cl->do_vthread(_target_h); // virtual thread
1977
    } else {
1978
      _hs_cl->do_thread(target);     // platform thread
1979
    }
1980
  }
1981
};
1982

1983
// Supports platform and virtual threads.
1984
// JvmtiVTMSTransitionDisabler is always set by this function.
1985
void
1986
JvmtiHandshake::execute(JvmtiUnitedHandshakeClosure* hs_cl, jthread target) {
1987
  JavaThread* current = JavaThread::current();
1988
  HandleMark hm(current);
1989

1990
  JvmtiVTMSTransitionDisabler disabler(target);
1991
  ThreadsListHandle tlh(current);
1992
  JavaThread* java_thread = nullptr;
1993
  oop thread_obj = nullptr;
1994

1995
  jvmtiError err = JvmtiEnvBase::get_threadOop_and_JavaThread(tlh.list(), target, current, &java_thread, &thread_obj);
1996
  if (err != JVMTI_ERROR_NONE) {
1997
    hs_cl->set_result(err);
1998
    return;
1999
  }
2000
  Handle target_h(current, thread_obj);
2001
  execute(hs_cl, &tlh, java_thread, target_h);
2002
}
2003

2004
// Supports platform and virtual threads.
2005
// A virtual thread is always identified by the target_h oop handle.
2006
// The target_jt is always nullptr for an unmounted virtual thread.
2007
// JvmtiVTMSTransitionDisabler has to be set before call to this function.
2008
void
2009
JvmtiHandshake::execute(JvmtiUnitedHandshakeClosure* hs_cl, ThreadsListHandle* tlh,
2010
                        JavaThread* target_jt, Handle target_h) {
2011
  JavaThread* current = JavaThread::current();
2012
  bool is_virtual = java_lang_VirtualThread::is_instance(target_h());
2013
  bool self = target_jt == current;
2014

2015
  assert(!Continuations::enabled() || self || !is_virtual || current->is_VTMS_transition_disabler(), "sanity check");
2016

2017
  hs_cl->set_target_jt(target_jt);   // can be needed in the virtual thread case
2018
  hs_cl->set_is_virtual(is_virtual); // can be needed in the virtual thread case
2019
  hs_cl->set_self(self);             // needed when suspend is required for non-current target thread
2020

2021
  if (is_virtual) {                // virtual thread
2022
    if (!JvmtiEnvBase::is_vthread_alive(target_h())) {
2023
      return;
2024
    }
2025
    if (target_jt == nullptr) {    // unmounted virtual thread
2026
      hs_cl->do_vthread(target_h); // execute handshake closure callback on current thread directly
2027
    }
2028
  }
2029
  if (target_jt != nullptr) {      // mounted virtual or platform thread
2030
    AdapterClosure acl(hs_cl, target_h);
2031
    if (self) {                    // target platform thread is current
2032
      acl.do_thread(target_jt);    // execute handshake closure callback on current thread directly
2033
    } else {
2034
      Handshake::execute(&acl, tlh, target_jt); // delegate to Handshake implementation
2035
    }
2036
  }
2037
}
2038

2039
void
2040
VM_GetThreadListStackTraces::doit() {
2041
  assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
2042

2043
  ResourceMark rm;
2044
  ThreadsListHandle tlh;
2045
  for (int i = 0; i < _thread_count; ++i) {
2046
    jthread jt = _thread_list[i];
2047
    JavaThread* java_thread = nullptr;
2048
    oop thread_oop = nullptr;
2049
    jvmtiError err = JvmtiEnvBase::get_threadOop_and_JavaThread(tlh.list(), jt, nullptr, &java_thread, &thread_oop);
2050

2051
    if (err != JVMTI_ERROR_NONE) {
2052
      // We got an error code so we don't have a JavaThread *, but
2053
      // only return an error from here if we didn't get a valid
2054
      // thread_oop.
2055
      // In the virtual thread case the get_threadOop_and_JavaThread is expected to correctly set
2056
      // the thread_oop and return JVMTI_ERROR_THREAD_NOT_ALIVE which we ignore here.
2057
      // The corresponding thread state will be recorded in the jvmtiStackInfo.state.
2058
      if (thread_oop == nullptr) {
2059
        _collector.set_result(err);
2060
        return;
2061
      }
2062
      // We have a valid thread_oop.
2063
    }
2064
    _collector.fill_frames(jt, java_thread, thread_oop);
2065
  }
2066
  _collector.allocate_and_fill_stacks(_thread_count);
2067
}
2068

2069
void
2070
GetSingleStackTraceClosure::doit() {
2071
  JavaThread *jt = _target_jt;
2072
  oop thread_oop = JNIHandles::resolve_external_guard(_jthread);
2073

2074
  if ((jt == nullptr || !jt->is_exiting()) && thread_oop != nullptr) {
2075
    ResourceMark rm;
2076
    _collector.fill_frames(_jthread, jt, thread_oop);
2077
    _collector.allocate_and_fill_stacks(1);
2078
    set_result(_collector.result());
2079
  }
2080
}
2081

2082
void
2083
GetSingleStackTraceClosure::do_thread(Thread *target) {
2084
  assert(_target_jt == JavaThread::cast(target), "sanity check");
2085
  doit();
2086
}
2087

2088
void
2089
GetSingleStackTraceClosure::do_vthread(Handle target_h) {
2090
  // Use jvmti_vthread() instead of vthread() as target could have temporarily changed
2091
  // identity to carrier thread (see VirtualThread.switchToCarrierThread).
2092
  assert(_target_jt == nullptr || _target_jt->jvmti_vthread() == target_h(), "sanity check");
2093
  doit();
2094
}
2095

2096
void
2097
VM_GetAllStackTraces::doit() {
2098
  assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
2099

2100
  ResourceMark rm;
2101
  _final_thread_count = 0;
2102
  for (JavaThreadIteratorWithHandle jtiwh; JavaThread *jt = jtiwh.next(); ) {
2103
    oop thread_oop = jt->threadObj();
2104
    if (thread_oop != nullptr &&
2105
        !jt->is_exiting() &&
2106
        java_lang_Thread::is_alive(thread_oop) &&
2107
        !jt->is_hidden_from_external_view() &&
2108
        !thread_oop->is_a(vmClasses::BoundVirtualThread_klass())) {
2109
      ++_final_thread_count;
2110
      // Handle block of the calling thread is used to create local refs.
2111
      _collector.fill_frames((jthread)JNIHandles::make_local(_calling_thread, thread_oop),
2112
                             jt, thread_oop);
2113
    }
2114
  }
2115
  _collector.allocate_and_fill_stacks(_final_thread_count);
2116
}
2117

2118
// Verifies that the top frame is a java frame in an expected state.
2119
// Deoptimizes frame if needed.
2120
// Checks that the frame method signature matches the return type (tos).
2121
// HandleMark must be defined in the caller only.
2122
// It is to keep a ret_ob_h handle alive after return to the caller.
2123
jvmtiError
2124
JvmtiEnvBase::check_top_frame(Thread* current_thread, JavaThread* java_thread,
2125
                              jvalue value, TosState tos, Handle* ret_ob_h) {
2126
  ResourceMark rm(current_thread);
2127

2128
  javaVFrame* jvf = jvf_for_thread_and_depth(java_thread, 0);
2129
  NULL_CHECK(jvf, JVMTI_ERROR_NO_MORE_FRAMES);
2130

2131
  if (jvf->method()->is_native()) {
2132
    return JVMTI_ERROR_OPAQUE_FRAME;
2133
  }
2134

2135
  // If the frame is a compiled one, need to deoptimize it.
2136
  if (jvf->is_compiled_frame()) {
2137
    if (!jvf->fr().can_be_deoptimized()) {
2138
      return JVMTI_ERROR_OPAQUE_FRAME;
2139
    }
2140
    Deoptimization::deoptimize_frame(java_thread, jvf->fr().id());
2141
  }
2142

2143
  // Get information about method return type
2144
  Symbol* signature = jvf->method()->signature();
2145

2146
  ResultTypeFinder rtf(signature);
2147
  TosState fr_tos = as_TosState(rtf.type());
2148
  if (fr_tos != tos) {
2149
    if (tos != itos || (fr_tos != btos && fr_tos != ztos && fr_tos != ctos && fr_tos != stos)) {
2150
      return JVMTI_ERROR_TYPE_MISMATCH;
2151
    }
2152
  }
2153

2154
  // Check that the jobject class matches the return type signature.
2155
  jobject jobj = value.l;
2156
  if (tos == atos && jobj != nullptr) { // null reference is allowed
2157
    Handle ob_h(current_thread, JNIHandles::resolve_external_guard(jobj));
2158
    NULL_CHECK(ob_h, JVMTI_ERROR_INVALID_OBJECT);
2159
    Klass* ob_k = ob_h()->klass();
2160
    NULL_CHECK(ob_k, JVMTI_ERROR_INVALID_OBJECT);
2161

2162
    // Method return type signature.
2163
    char* ty_sign = 1 + strchr(signature->as_C_string(), JVM_SIGNATURE_ENDFUNC);
2164

2165
    if (!VM_GetOrSetLocal::is_assignable(ty_sign, ob_k, current_thread)) {
2166
      return JVMTI_ERROR_TYPE_MISMATCH;
2167
    }
2168
    *ret_ob_h = ob_h;
2169
  }
2170
  return JVMTI_ERROR_NONE;
2171
} /* end check_top_frame */
2172

2173

2174
// ForceEarlyReturn<type> follows the PopFrame approach in many aspects.
2175
// Main difference is on the last stage in the interpreter.
2176
// The PopFrame stops method execution to continue execution
2177
// from the same method call instruction.
2178
// The ForceEarlyReturn forces return from method so the execution
2179
// continues at the bytecode following the method call.
2180

2181
// thread - NOT protected by ThreadsListHandle and NOT pre-checked
2182

2183
jvmtiError
2184
JvmtiEnvBase::force_early_return(jthread thread, jvalue value, TosState tos) {
2185
  JavaThread* current_thread = JavaThread::current();
2186
  HandleMark hm(current_thread);
2187

2188
  JvmtiVTMSTransitionDisabler disabler(thread);
2189
  ThreadsListHandle tlh(current_thread);
2190

2191
  JavaThread* java_thread = nullptr;
2192
  oop thread_obj = nullptr;
2193
  jvmtiError err = get_threadOop_and_JavaThread(tlh.list(), thread, current_thread, &java_thread, &thread_obj);
2194

2195
  if (err != JVMTI_ERROR_NONE) {
2196
    return err;
2197
  }
2198
  Handle thread_handle(current_thread, thread_obj);
2199
  bool self = java_thread == current_thread;
2200

2201
  err = check_non_suspended_or_opaque_frame(java_thread, thread_obj, self);
2202
  if (err != JVMTI_ERROR_NONE) {
2203
    return err;
2204
  }
2205

2206
  // retrieve or create the state
2207
  JvmtiThreadState* state = JvmtiThreadState::state_for(java_thread);
2208
  if (state == nullptr) {
2209
    return JVMTI_ERROR_THREAD_NOT_ALIVE;
2210
  }
2211

2212
  // Eagerly reallocate scalar replaced objects.
2213
  EscapeBarrier eb(true, current_thread, java_thread);
2214
  if (!eb.deoptimize_objects(0)) {
2215
    // Reallocation of scalar replaced objects failed -> return with error
2216
    return JVMTI_ERROR_OUT_OF_MEMORY;
2217
  }
2218

2219
  MutexLocker mu(JvmtiThreadState_lock);
2220
  SetForceEarlyReturn op(state, value, tos);
2221
  JvmtiHandshake::execute(&op, &tlh, java_thread, thread_handle);
2222
  return op.result();
2223
}
2224

2225
void
2226
SetForceEarlyReturn::doit(Thread *target) {
2227
  JavaThread* java_thread = JavaThread::cast(target);
2228
  Thread* current_thread = Thread::current();
2229
  HandleMark   hm(current_thread);
2230

2231
  if (java_thread->is_exiting()) {
2232
    return; /* JVMTI_ERROR_THREAD_NOT_ALIVE (default) */
2233
  }
2234

2235
  // Check to see if a ForceEarlyReturn was already in progress
2236
  if (_state->is_earlyret_pending()) {
2237
    // Probably possible for JVMTI clients to trigger this, but the
2238
    // JPDA backend shouldn't allow this to happen
2239
    _result = JVMTI_ERROR_INTERNAL;
2240
    return;
2241
  }
2242
  {
2243
    // The same as for PopFrame. Workaround bug:
2244
    //  4812902: popFrame hangs if the method is waiting at a synchronize
2245
    // Catch this condition and return an error to avoid hanging.
2246
    // Now JVMTI spec allows an implementation to bail out with an opaque
2247
    // frame error.
2248
    OSThread* osThread = java_thread->osthread();
2249
    if (osThread->get_state() == MONITOR_WAIT) {
2250
      _result = JVMTI_ERROR_OPAQUE_FRAME;
2251
      return;
2252
    }
2253
  }
2254

2255
  Handle ret_ob_h;
2256
  _result = JvmtiEnvBase::check_top_frame(current_thread, java_thread, _value, _tos, &ret_ob_h);
2257
  if (_result != JVMTI_ERROR_NONE) {
2258
    return;
2259
  }
2260
  assert(_tos != atos || _value.l == nullptr || ret_ob_h() != nullptr,
2261
         "return object oop must not be null if jobject is not null");
2262

2263
  // Update the thread state to reflect that the top frame must be
2264
  // forced to return.
2265
  // The current frame will be returned later when the suspended
2266
  // thread is resumed and right before returning from VM to Java.
2267
  // (see call_VM_base() in assembler_<cpu>.cpp).
2268

2269
  _state->set_earlyret_pending();
2270
  _state->set_earlyret_oop(ret_ob_h());
2271
  _state->set_earlyret_value(_value, _tos);
2272

2273
  // Set pending step flag for this early return.
2274
  // It is cleared when next step event is posted.
2275
  _state->set_pending_step_for_earlyret();
2276
}
2277

2278
void
2279
JvmtiMonitorClosure::do_monitor(ObjectMonitor* mon) {
2280
  if ( _error != JVMTI_ERROR_NONE) {
2281
    // Error occurred in previous iteration so no need to add
2282
    // to the list.
2283
    return;
2284
  }
2285
  // Filter out on stack monitors collected during stack walk.
2286
  oop obj = mon->object();
2287

2288
  if (obj == nullptr) {
2289
    // This can happen if JNI code drops all references to the
2290
    // owning object.
2291
    return;
2292
  }
2293

2294
  bool found = false;
2295
  for (int j = 0; j < _owned_monitors_list->length(); j++) {
2296
    jobject jobj = ((jvmtiMonitorStackDepthInfo*)_owned_monitors_list->at(j))->monitor;
2297
    oop check = JNIHandles::resolve(jobj);
2298
    if (check == obj) {
2299
      // On stack monitor already collected during the stack walk.
2300
      found = true;
2301
      break;
2302
    }
2303
  }
2304
  if (found == false) {
2305
    // This is off stack monitor (e.g. acquired via jni MonitorEnter).
2306
    jvmtiError err;
2307
    jvmtiMonitorStackDepthInfo *jmsdi;
2308
    err = _env->allocate(sizeof(jvmtiMonitorStackDepthInfo), (unsigned char **)&jmsdi);
2309
    if (err != JVMTI_ERROR_NONE) {
2310
      _error = err;
2311
      return;
2312
    }
2313
    Handle hobj(Thread::current(), obj);
2314
    jmsdi->monitor = _env->jni_reference(_calling_thread, hobj);
2315
    // stack depth is unknown for this monitor.
2316
    jmsdi->stack_depth = -1;
2317
    _owned_monitors_list->append(jmsdi);
2318
  }
2319
}
2320

2321
GrowableArray<OopHandle>* JvmtiModuleClosure::_tbl = nullptr;
2322

2323
void JvmtiModuleClosure::do_module(ModuleEntry* entry) {
2324
  assert_locked_or_safepoint(Module_lock);
2325
  OopHandle module = entry->module_handle();
2326
  guarantee(module.resolve() != nullptr, "module object is null");
2327
  _tbl->push(module);
2328
}
2329

2330
jvmtiError
2331
JvmtiModuleClosure::get_all_modules(JvmtiEnv* env, jint* module_count_ptr, jobject** modules_ptr) {
2332
  ResourceMark rm;
2333
  MutexLocker mcld(ClassLoaderDataGraph_lock);
2334
  MutexLocker ml(Module_lock);
2335

2336
  _tbl = new GrowableArray<OopHandle>(77);
2337
  if (_tbl == nullptr) {
2338
    return JVMTI_ERROR_OUT_OF_MEMORY;
2339
  }
2340

2341
  // Iterate over all the modules loaded to the system.
2342
  ClassLoaderDataGraph::modules_do_keepalive(&do_module);
2343

2344
  jint len = _tbl->length();
2345
  guarantee(len > 0, "at least one module must be present");
2346

2347
  jobject* array = (jobject*)env->jvmtiMalloc((jlong)(len * sizeof(jobject)));
2348
  if (array == nullptr) {
2349
    return JVMTI_ERROR_OUT_OF_MEMORY;
2350
  }
2351
  for (jint idx = 0; idx < len; idx++) {
2352
    array[idx] = JNIHandles::make_local(_tbl->at(idx).resolve());
2353
  }
2354
  _tbl = nullptr;
2355
  *modules_ptr = array;
2356
  *module_count_ptr = len;
2357
  return JVMTI_ERROR_NONE;
2358
}
2359

2360
void
2361
UpdateForPopTopFrameClosure::doit(Thread *target) {
2362
  Thread* current_thread  = Thread::current();
2363
  HandleMark hm(current_thread);
2364
  JavaThread* java_thread = JavaThread::cast(target);
2365

2366
  if (java_thread->is_exiting()) {
2367
    return; /* JVMTI_ERROR_THREAD_NOT_ALIVE (default) */
2368
  }
2369
  assert(java_thread == _state->get_thread(), "Must be");
2370

2371
  // Check to see if a PopFrame was already in progress
2372
  if (java_thread->popframe_condition() != JavaThread::popframe_inactive) {
2373
    // Probably possible for JVMTI clients to trigger this, but the
2374
    // JPDA backend shouldn't allow this to happen
2375
    _result = JVMTI_ERROR_INTERNAL;
2376
    return;
2377
  }
2378

2379
  // Was workaround bug
2380
  //    4812902: popFrame hangs if the method is waiting at a synchronize
2381
  // Catch this condition and return an error to avoid hanging.
2382
  // Now JVMTI spec allows an implementation to bail out with an opaque frame error.
2383
  OSThread* osThread = java_thread->osthread();
2384
  if (osThread->get_state() == MONITOR_WAIT) {
2385
    _result = JVMTI_ERROR_OPAQUE_FRAME;
2386
    return;
2387
  }
2388

2389
  ResourceMark rm(current_thread);
2390
  // Check if there is more than one Java frame in this thread, that the top two frames
2391
  // are Java (not native) frames, and that there is no intervening VM frame
2392
  int frame_count = 0;
2393
  bool is_interpreted[2];
2394
  intptr_t *frame_sp[2];
2395
  // The 2-nd arg of constructor is needed to stop iterating at java entry frame.
2396
  for (vframeStream vfs(java_thread, true, false /* process_frames */); !vfs.at_end(); vfs.next()) {
2397
    methodHandle mh(current_thread, vfs.method());
2398
    if (mh->is_native()) {
2399
      _result = JVMTI_ERROR_OPAQUE_FRAME;
2400
      return;
2401
    }
2402
    is_interpreted[frame_count] = vfs.is_interpreted_frame();
2403
    frame_sp[frame_count] = vfs.frame_id();
2404
    if (++frame_count > 1) break;
2405
  }
2406
  if (frame_count < 2)  {
2407
    // We haven't found two adjacent non-native Java frames on the top.
2408
    // There can be two situations here:
2409
    //  1. There are no more java frames
2410
    //  2. Two top java frames are separated by non-java native frames
2411
    if (JvmtiEnvBase::jvf_for_thread_and_depth(java_thread, 1) == nullptr) {
2412
      _result = JVMTI_ERROR_NO_MORE_FRAMES;
2413
      return;
2414
    } else {
2415
      // Intervening non-java native or VM frames separate java frames.
2416
      // Current implementation does not support this. See bug #5031735.
2417
      // In theory it is possible to pop frames in such cases.
2418
      _result = JVMTI_ERROR_OPAQUE_FRAME;
2419
      return;
2420
    }
2421
  }
2422

2423
  // If any of the top 2 frames is a compiled one, need to deoptimize it
2424
  for (int i = 0; i < 2; i++) {
2425
    if (!is_interpreted[i]) {
2426
      Deoptimization::deoptimize_frame(java_thread, frame_sp[i]);
2427
    }
2428
  }
2429

2430
  // Update the thread state to reflect that the top frame is popped
2431
  // so that cur_stack_depth is maintained properly and all frameIDs
2432
  // are invalidated.
2433
  // The current frame will be popped later when the suspended thread
2434
  // is resumed and right before returning from VM to Java.
2435
  // (see call_VM_base() in assembler_<cpu>.cpp).
2436

2437
  // It's fine to update the thread state here because no JVMTI events
2438
  // shall be posted for this PopFrame.
2439

2440
  _state->update_for_pop_top_frame();
2441
  java_thread->set_popframe_condition(JavaThread::popframe_pending_bit);
2442
  // Set pending step flag for this popframe and it is cleared when next
2443
  // step event is posted.
2444
  _state->set_pending_step_for_popframe();
2445
  _result = JVMTI_ERROR_NONE;
2446
}
2447

2448
void
2449
SetFramePopClosure::do_thread(Thread *target) {
2450
  Thread* current = Thread::current();
2451
  ResourceMark rm(current); // vframes are resource allocated
2452
  JavaThread* java_thread = JavaThread::cast(target);
2453

2454
  if (java_thread->is_exiting()) {
2455
    return; // JVMTI_ERROR_THREAD_NOT_ALIVE (default)
2456
  }
2457

2458
  if (!_self && !java_thread->is_suspended()) {
2459
    _result = JVMTI_ERROR_THREAD_NOT_SUSPENDED;
2460
    return;
2461
  }
2462
  if (!java_thread->has_last_Java_frame()) {
2463
    _result = JVMTI_ERROR_NO_MORE_FRAMES;
2464
    return;
2465
  }
2466
  assert(_state->get_thread_or_saved() == java_thread, "Must be");
2467

2468
  RegisterMap reg_map(java_thread,
2469
                      RegisterMap::UpdateMap::include,
2470
                      RegisterMap::ProcessFrames::skip,
2471
                      RegisterMap::WalkContinuation::include);
2472
  javaVFrame* jvf = JvmtiEnvBase::get_cthread_last_java_vframe(java_thread, &reg_map);
2473
  _result = ((JvmtiEnvBase*)_env)->set_frame_pop(_state, jvf, _depth);
2474
}
2475

2476
void
2477
SetFramePopClosure::do_vthread(Handle target_h) {
2478
  Thread* current = Thread::current();
2479
  ResourceMark rm(current); // vframes are resource allocated
2480

2481
  if (!_self && !JvmtiVTSuspender::is_vthread_suspended(target_h())) {
2482
    _result = JVMTI_ERROR_THREAD_NOT_SUSPENDED;
2483
    return;
2484
  }
2485
  javaVFrame *jvf = JvmtiEnvBase::get_vthread_jvf(target_h());
2486
  _result = ((JvmtiEnvBase*)_env)->set_frame_pop(_state, jvf, _depth);
2487
}
2488

2489
void
2490
GetOwnedMonitorInfoClosure::do_thread(Thread *target) {
2491
  JavaThread *jt = JavaThread::cast(target);
2492
  if (!jt->is_exiting() && (jt->threadObj() != nullptr)) {
2493
    _result = ((JvmtiEnvBase *)_env)->get_owned_monitors(_calling_thread,
2494
                                                         jt,
2495
                                                         _owned_monitors_list);
2496
  }
2497
}
2498

2499
void
2500
GetOwnedMonitorInfoClosure::do_vthread(Handle target_h) {
2501
  assert(_target_jt != nullptr, "sanity check");
2502
  Thread* current = Thread::current();
2503
  ResourceMark rm(current); // vframes are resource allocated
2504
  HandleMark hm(current);
2505

2506
  javaVFrame *jvf = JvmtiEnvBase::get_vthread_jvf(target_h());
2507

2508
  if (!_target_jt->is_exiting() && _target_jt->threadObj() != nullptr) {
2509
    _result = ((JvmtiEnvBase *)_env)->get_owned_monitors(_calling_thread,
2510
                                                         _target_jt,
2511
                                                         jvf,
2512
                                                         _owned_monitors_list);
2513
  }
2514
}
2515

2516
void
2517
GetCurrentContendedMonitorClosure::do_thread(Thread *target) {
2518
  JavaThread *jt = JavaThread::cast(target);
2519
  if (!jt->is_exiting() && (jt->threadObj() != nullptr)) {
2520
    _result = ((JvmtiEnvBase *)_env)->get_current_contended_monitor(_calling_thread,
2521
                                                                    jt,
2522
                                                                    _owned_monitor_ptr,
2523
                                                                    _is_virtual);
2524
  }
2525
}
2526

2527
void
2528
GetCurrentContendedMonitorClosure::do_vthread(Handle target_h) {
2529
  if (_target_jt == nullptr) {
2530
    _result = JVMTI_ERROR_NONE; // target virtual thread is unmounted
2531
    return;
2532
  }
2533
  // mounted virtual thread case
2534
  do_thread(_target_jt);
2535
}
2536

2537
void
2538
GetStackTraceClosure::do_thread(Thread *target) {
2539
  Thread* current = Thread::current();
2540
  ResourceMark rm(current);
2541

2542
  JavaThread *jt = JavaThread::cast(target);
2543
  if (!jt->is_exiting() && jt->threadObj() != nullptr) {
2544
    _result = ((JvmtiEnvBase *)_env)->get_stack_trace(jt,
2545
                                                      _start_depth, _max_count,
2546
                                                      _frame_buffer, _count_ptr);
2547
  }
2548
}
2549

2550
void
2551
GetStackTraceClosure::do_vthread(Handle target_h) {
2552
  Thread* current = Thread::current();
2553
  ResourceMark rm(current);
2554

2555
  javaVFrame *jvf = JvmtiEnvBase::get_vthread_jvf(target_h());
2556
  _result = ((JvmtiEnvBase *)_env)->get_stack_trace(jvf,
2557
                                                    _start_depth, _max_count,
2558
                                                    _frame_buffer, _count_ptr);
2559
}
2560

2561
#ifdef ASSERT
2562
void
2563
PrintStackTraceClosure::do_thread_impl(Thread *target) {
2564
  JavaThread *java_thread = JavaThread::cast(target);
2565
  Thread *current_thread = Thread::current();
2566

2567
  ResourceMark rm (current_thread);
2568
  const char* tname = JvmtiTrace::safe_get_thread_name(java_thread);
2569
  oop t_oop = java_thread->jvmti_vthread();
2570
  t_oop = t_oop == nullptr ? java_thread->threadObj() : t_oop;
2571
  bool is_vt_suspended = java_lang_VirtualThread::is_instance(t_oop) && JvmtiVTSuspender::is_vthread_suspended(t_oop);
2572

2573
  log_error(jvmti)("%s(%s) exiting: %d is_susp: %d is_thread_susp: %d is_vthread_susp: %d "
2574
                   "is_VTMS_transition_disabler: %d, is_in_VTMS_transition = %d\n",
2575
                   tname, java_thread->name(), java_thread->is_exiting(),
2576
                   java_thread->is_suspended(), java_thread->is_carrier_thread_suspended(), is_vt_suspended,
2577
                   java_thread->is_VTMS_transition_disabler(), java_thread->is_in_VTMS_transition());
2578

2579
  if (java_thread->has_last_Java_frame()) {
2580
    RegisterMap reg_map(java_thread,
2581
                        RegisterMap::UpdateMap::include,
2582
                        RegisterMap::ProcessFrames::include,
2583
                        RegisterMap::WalkContinuation::skip);
2584
    ResourceMark rm(current_thread);
2585
    HandleMark hm(current_thread);
2586
    javaVFrame *jvf = java_thread->last_java_vframe(&reg_map);
2587
    while (jvf != nullptr) {
2588
      log_error(jvmti)("  %s:%d",
2589
                       jvf->method()->external_name(),
2590
                       jvf->method()->line_number_from_bci(jvf->bci()));
2591
      jvf = jvf->java_sender();
2592
    }
2593
  }
2594
  log_error(jvmti)("\n");
2595
}
2596

2597
void
2598
PrintStackTraceClosure::do_thread(Thread *target) {
2599
  JavaThread *java_thread = JavaThread::cast(target);
2600
  Thread *current_thread = Thread::current();
2601

2602
  assert(SafepointSynchronize::is_at_safepoint() ||
2603
         java_thread->is_handshake_safe_for(current_thread),
2604
         "call by myself / at safepoint / at handshake");
2605

2606
  PrintStackTraceClosure::do_thread_impl(target);
2607
}
2608
#endif
2609

2610
void
2611
GetFrameCountClosure::do_thread(Thread *target) {
2612
  JavaThread* jt = JavaThread::cast(target);
2613
  assert(target == jt, "just checking");
2614

2615
  if (!jt->is_exiting() && jt->threadObj() != nullptr) {
2616
    _result = ((JvmtiEnvBase*)_env)->get_frame_count(jt, _count_ptr);
2617
  }
2618
}
2619

2620
void
2621
GetFrameCountClosure::do_vthread(Handle target_h) {
2622
  _result = ((JvmtiEnvBase*)_env)->get_frame_count(target_h(), _count_ptr);
2623
}
2624

2625
void
2626
GetFrameLocationClosure::do_thread(Thread *target) {
2627
  JavaThread *jt = JavaThread::cast(target);
2628
  assert(target == jt, "just checking");
2629

2630
  if (!jt->is_exiting() && jt->threadObj() != nullptr) {
2631
    _result = ((JvmtiEnvBase*)_env)->get_frame_location(jt, _depth,
2632
                                                        _method_ptr, _location_ptr);
2633
  }
2634
}
2635

2636
void
2637
GetFrameLocationClosure::do_vthread(Handle target_h) {
2638
  _result = ((JvmtiEnvBase*)_env)->get_frame_location(target_h(), _depth,
2639
                                                      _method_ptr, _location_ptr);
2640
}
2641