1 /*
   2  * Copyright (c) 1997, 2023, Oracle and/or its affiliates. All rights reserved.
   3  * Copyright (c) 2021, Azul Systems, Inc. All rights reserved.
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This code is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 only, as
   8  * published by the Free Software Foundation.
   9  *
  10  * This code is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13  * version 2 for more details (a copy is included in the LICENSE file that
  14  * accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License version
  17  * 2 along with this work; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  19  *
  20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  21  * or visit www.oracle.com if you need additional information or have any
  22  * questions.
  23  *
  24  */
  25 
  26 #include "precompiled.hpp"
  27 #include "cds/cds_globals.hpp"
  28 #include "cds/metaspaceShared.hpp"
  29 #include "classfile/classLoader.hpp"
  30 #include "classfile/javaClasses.hpp"
  31 #include "classfile/javaThreadStatus.hpp"
  32 #include "classfile/systemDictionary.hpp"
  33 #include "classfile/vmClasses.hpp"
  34 #include "classfile/vmSymbols.hpp"
  35 #include "compiler/compileBroker.hpp"
  36 #include "compiler/compileTask.hpp"
  37 #include "compiler/compilerThread.hpp"
  38 #include "gc/shared/barrierSet.hpp"
  39 #include "gc/shared/barrierSetNMethod.hpp"
  40 #include "gc/shared/gcVMOperations.hpp"
  41 #include "gc/shared/oopStorage.hpp"
  42 #include "gc/shared/oopStorageSet.hpp"
  43 #include "gc/shared/stringdedup/stringDedup.hpp"
  44 #include "jfr/jfrEvents.hpp"
  45 #include "jvm.h"
  46 #include "jvmtifiles/jvmtiEnv.hpp"
  47 #include "logging/log.hpp"
  48 #include "logging/logAsyncWriter.hpp"
  49 #include "logging/logConfiguration.hpp"
  50 #include "memory/allocation.inline.hpp"
  51 #include "memory/iterator.hpp"
  52 #include "memory/oopFactory.hpp"
  53 #include "memory/resourceArea.hpp"
  54 #include "memory/universe.hpp"
  55 #include "oops/instanceKlass.hpp"
  56 #include "oops/klass.inline.hpp"
  57 #include "oops/oop.inline.hpp"
  58 #include "oops/symbol.hpp"
  59 #include "prims/jvmtiAgentList.hpp"
  60 #include "prims/jvm_misc.hpp"
  61 #include "runtime/arguments.hpp"
  62 #include "runtime/fieldDescriptor.inline.hpp"
  63 #include "runtime/flags/jvmFlagLimit.hpp"
  64 #include "runtime/handles.inline.hpp"
  65 #include "runtime/globals.hpp"
  66 #include "runtime/interfaceSupport.inline.hpp"
  67 #include "runtime/java.hpp"
  68 #include "runtime/javaCalls.hpp"
  69 #include "runtime/javaThread.inline.hpp"
  70 #include "runtime/jniHandles.inline.hpp"
  71 #include "runtime/jniPeriodicChecker.hpp"
  72 #include "runtime/lockStack.inline.hpp"
  73 #include "runtime/monitorDeflationThread.hpp"
  74 #include "runtime/mutexLocker.hpp"
  75 #include "runtime/nonJavaThread.hpp"
  76 #include "runtime/objectMonitor.inline.hpp"
  77 #include "runtime/osThread.hpp"
  78 #include "runtime/safepoint.hpp"
  79 #include "runtime/safepointMechanism.inline.hpp"
  80 #include "runtime/safepointVerifiers.hpp"
  81 #include "runtime/serviceThread.hpp"
  82 #include "runtime/sharedRuntime.hpp"
  83 #include "runtime/statSampler.hpp"
  84 #include "runtime/stubCodeGenerator.hpp"
  85 #include "runtime/thread.inline.hpp"
  86 #include "runtime/threads.hpp"
  87 #include "runtime/threadSMR.inline.hpp"
  88 #include "runtime/timer.hpp"
  89 #include "runtime/timerTrace.hpp"
  90 #include "runtime/trimNativeHeap.hpp"
  91 #include "runtime/vmOperations.hpp"
  92 #include "runtime/vm_version.hpp"
  93 #include "services/attachListener.hpp"
  94 #include "services/management.hpp"
  95 #include "services/memTracker.hpp"
  96 #include "services/threadIdTable.hpp"
  97 #include "services/threadService.hpp"
  98 #include "utilities/dtrace.hpp"
  99 #include "utilities/events.hpp"
 100 #include "utilities/macros.hpp"
 101 #include "utilities/vmError.hpp"
 102 #if INCLUDE_JVMCI
 103 #include "jvmci/jvmci.hpp"
 104 #include "jvmci/jvmciEnv.hpp"
 105 #endif
 106 #ifdef COMPILER2
 107 #include "opto/idealGraphPrinter.hpp"
 108 #endif
 109 #if INCLUDE_RTM_OPT
 110 #include "runtime/rtmLocking.hpp"
 111 #endif
 112 #if INCLUDE_JFR
 113 #include "jfr/jfr.hpp"
 114 #endif
 115 #if INCLUDE_VM_STRUCTS
 116 #include "runtime/vmStructs.hpp"
 117 #endif
 118 
 119 // Initialization after module runtime initialization
 120 void universe_post_module_init();  // must happen after call_initPhase2
 121 
 122 
 123 static void initialize_class(Symbol* class_name, TRAPS) {
 124   Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
 125   InstanceKlass::cast(klass)->initialize(CHECK);
 126 }
 127 
 128 
 129 // Creates the initial ThreadGroup
 130 static Handle create_initial_thread_group(TRAPS) {
 131   Handle system_instance = JavaCalls::construct_new_instance(
 132                             vmClasses::ThreadGroup_klass(),
 133                             vmSymbols::void_method_signature(),
 134                             CHECK_NH);
 135   Universe::set_system_thread_group(system_instance());
 136 
 137   Handle string = java_lang_String::create_from_str("main", CHECK_NH);
 138   Handle main_instance = JavaCalls::construct_new_instance(
 139                             vmClasses::ThreadGroup_klass(),
 140                             vmSymbols::threadgroup_string_void_signature(),
 141                             system_instance,
 142                             string,
 143                             CHECK_NH);
 144   return main_instance;
 145 }
 146 
 147 // Creates the initial Thread, and sets it to running.
 148 static void create_initial_thread(Handle thread_group, JavaThread* thread,
 149                                  TRAPS) {
 150   InstanceKlass* ik = vmClasses::Thread_klass();
 151   assert(ik->is_initialized(), "must be");
 152   instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
 153 
 154   // Cannot use JavaCalls::construct_new_instance because the java.lang.Thread
 155   // constructor calls Thread.current(), which must be set here for the
 156   // initial thread.
 157   java_lang_Thread::set_thread(thread_oop(), thread);
 158   thread->set_threadOopHandles(thread_oop());
 159 
 160   Handle string = java_lang_String::create_from_str("main", CHECK);
 161 
 162   JavaValue result(T_VOID);
 163   JavaCalls::call_special(&result, thread_oop,
 164                           ik,
 165                           vmSymbols::object_initializer_name(),
 166                           vmSymbols::threadgroup_string_void_signature(),
 167                           thread_group,
 168                           string,
 169                           CHECK);
 170 
 171   // Set thread status to running since main thread has
 172   // been started and running.
 173   java_lang_Thread::set_thread_status(thread_oop(),
 174                                       JavaThreadStatus::RUNNABLE);
 175 }
 176 
 177 // Extract version and vendor specific information from
 178 // java.lang.VersionProps fields.
 179 // Returned char* is allocated in the thread's resource area
 180 // so must be copied for permanency.
 181 static const char* get_java_version_info(InstanceKlass* ik,
 182                                          Symbol* field_name) {
 183   fieldDescriptor fd;
 184   bool found = ik != nullptr &&
 185                ik->find_local_field(field_name,
 186                                     vmSymbols::string_signature(), &fd);
 187   if (found) {
 188     oop name_oop = ik->java_mirror()->obj_field(fd.offset());
 189     if (name_oop == nullptr) {
 190       return nullptr;
 191     }
 192     const char* name = java_lang_String::as_utf8_string(name_oop);
 193     return name;
 194   } else {
 195     return nullptr;
 196   }
 197 }
 198 
 199 // ======= Threads ========
 200 
 201 // The Threads class links together all active threads, and provides
 202 // operations over all threads. It is protected by the Threads_lock,
 203 // which is also used in other global contexts like safepointing.
 204 // ThreadsListHandles are used to safely perform operations on one
 205 // or more threads without the risk of the thread exiting during the
 206 // operation.
 207 //
 208 // Note: The Threads_lock is currently more widely used than we
 209 // would like. We are actively migrating Threads_lock uses to other
 210 // mechanisms in order to reduce Threads_lock contention.
 211 
 212 int         Threads::_number_of_threads = 0;
 213 int         Threads::_number_of_non_daemon_threads = 0;
 214 int         Threads::_return_code = 0;
 215 uintx       Threads::_thread_claim_token = 1; // Never zero.
 216 
 217 #ifdef ASSERT
 218 bool        Threads::_vm_complete = false;
 219 #endif
 220 
 221 // General purpose hook into Java code, run once when the VM is initialized.
 222 // The Java library method itself may be changed independently from the VM.
 223 static void call_postVMInitHook(TRAPS) {
 224   Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_vm_PostVMInitHook(), THREAD);
 225   if (klass != nullptr) {
 226     JavaValue result(T_VOID);
 227     JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
 228                            vmSymbols::void_method_signature(),
 229                            CHECK);
 230   }
 231 }
 232 
 233 // All NonJavaThreads (i.e., every non-JavaThread in the system).
 234 void Threads::non_java_threads_do(ThreadClosure* tc) {
 235   NoSafepointVerifier nsv;
 236   for (NonJavaThread::Iterator njti; !njti.end(); njti.step()) {
 237     tc->do_thread(njti.current());
 238   }
 239 }
 240 
 241 // All JavaThreads
 242 #define ALL_JAVA_THREADS(X) \
 243   for (JavaThread* X : *ThreadsSMRSupport::get_java_thread_list())
 244 
 245 // All JavaThreads
 246 void Threads::java_threads_do(ThreadClosure* tc) {
 247   assert_locked_or_safepoint(Threads_lock);
 248   // ALL_JAVA_THREADS iterates through all JavaThreads.
 249   ALL_JAVA_THREADS(p) {
 250     tc->do_thread(p);
 251   }
 252 }
 253 
 254 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system).
 255 void Threads::threads_do(ThreadClosure* tc) {
 256   assert_locked_or_safepoint(Threads_lock);
 257   java_threads_do(tc);
 258   non_java_threads_do(tc);
 259 }
 260 
 261 void Threads::possibly_parallel_threads_do(bool is_par, ThreadClosure* tc) {
 262   assert_at_safepoint();
 263 
 264   uintx claim_token = Threads::thread_claim_token();
 265   ALL_JAVA_THREADS(p) {
 266     if (p->claim_threads_do(is_par, claim_token)) {
 267       tc->do_thread(p);
 268     }
 269   }
 270   for (NonJavaThread::Iterator njti; !njti.end(); njti.step()) {
 271     Thread* current = njti.current();
 272     if (current->claim_threads_do(is_par, claim_token)) {
 273       tc->do_thread(current);
 274     }
 275   }
 276 }
 277 
 278 // The system initialization in the library has three phases.
 279 //
 280 // Phase 1: java.lang.System class initialization
 281 //     java.lang.System is a primordial class loaded and initialized
 282 //     by the VM early during startup.  java.lang.System.<clinit>
 283 //     only does registerNatives and keeps the rest of the class
 284 //     initialization work later until thread initialization completes.
 285 //
 286 //     System.initPhase1 initializes the system properties, the static
 287 //     fields in, out, and err. Set up java signal handlers, OS-specific
 288 //     system settings, and thread group of the main thread.
 289 static void call_initPhase1(TRAPS) {
 290   Klass* klass = vmClasses::System_klass();
 291   JavaValue result(T_VOID);
 292   JavaCalls::call_static(&result, klass, vmSymbols::initPhase1_name(),
 293                                          vmSymbols::void_method_signature(), CHECK);
 294 }
 295 
 296 // Phase 2. Module system initialization
 297 //     This will initialize the module system.  Only java.base classes
 298 //     can be loaded until phase 2 completes.
 299 //
 300 //     Call System.initPhase2 after the compiler initialization and jsr292
 301 //     classes get initialized because module initialization runs a lot of java
 302 //     code, that for performance reasons, should be compiled.  Also, this will
 303 //     enable the startup code to use lambda and other language features in this
 304 //     phase and onward.
 305 //
 306 //     After phase 2, The VM will begin search classes from -Xbootclasspath/a.
 307 static void call_initPhase2(TRAPS) {
 308   TraceTime timer("Initialize module system", TRACETIME_LOG(Info, startuptime));
 309 
 310   Klass* klass = vmClasses::System_klass();
 311 
 312   JavaValue result(T_INT);
 313   JavaCallArguments args;
 314   args.push_int(DisplayVMOutputToStderr);
 315   args.push_int(log_is_enabled(Debug, init)); // print stack trace if exception thrown
 316   JavaCalls::call_static(&result, klass, vmSymbols::initPhase2_name(),
 317                                          vmSymbols::boolean_boolean_int_signature(), &args, CHECK);
 318   if (result.get_jint() != JNI_OK) {
 319     vm_exit_during_initialization(); // no message or exception
 320   }
 321 
 322   universe_post_module_init();
 323 }
 324 
 325 // Phase 3. final setup - set security manager, system class loader and TCCL
 326 //
 327 //     This will instantiate and set the security manager, set the system class
 328 //     loader as well as the thread context class loader.  The security manager
 329 //     and system class loader may be a custom class loaded from -Xbootclasspath/a,
 330 //     other modules or the application's classpath.
 331 static void call_initPhase3(TRAPS) {
 332   Klass* klass = vmClasses::System_klass();
 333   JavaValue result(T_VOID);
 334   JavaCalls::call_static(&result, klass, vmSymbols::initPhase3_name(),
 335                                          vmSymbols::void_method_signature(), CHECK);
 336 }
 337 
 338 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
 339   TraceTime timer("Initialize java.lang classes", TRACETIME_LOG(Info, startuptime));
 340 
 341   initialize_class(vmSymbols::java_lang_String(), CHECK);
 342 
 343   // Inject CompactStrings value after the static initializers for String ran.
 344   java_lang_String::set_compact_strings(CompactStrings);
 345 
 346   // Initialize java_lang.System (needed before creating the thread)
 347   initialize_class(vmSymbols::java_lang_System(), CHECK);
 348   // The VM creates & returns objects of this class. Make sure it's initialized.
 349   initialize_class(vmSymbols::java_lang_Class(), CHECK);
 350   initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
 351   Handle thread_group = create_initial_thread_group(CHECK);
 352   Universe::set_main_thread_group(thread_group());
 353   initialize_class(vmSymbols::java_lang_Thread(), CHECK);
 354   create_initial_thread(thread_group, main_thread, CHECK);
 355 
 356   // The VM creates objects of this class.
 357   initialize_class(vmSymbols::java_lang_Module(), CHECK);
 358 
 359 #ifdef ASSERT
 360   InstanceKlass *k = vmClasses::UnsafeConstants_klass();
 361   assert(k->is_not_initialized(), "UnsafeConstants should not already be initialized");
 362 #endif
 363 
 364   // initialize the hardware-specific constants needed by Unsafe
 365   initialize_class(vmSymbols::jdk_internal_misc_UnsafeConstants(), CHECK);
 366   jdk_internal_misc_UnsafeConstants::set_unsafe_constants();
 367 
 368   // The VM preresolves methods to these classes. Make sure that they get initialized
 369   initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
 370   initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
 371 
 372   // Phase 1 of the system initialization in the library, java.lang.System class initialization
 373   call_initPhase1(CHECK);
 374 
 375   // Get the Java runtime name, version, and vendor info after java.lang.System is initialized.
 376   // Some values are actually configure-time constants but some can be set via the jlink tool and
 377   // so must be read dynamically. We treat them all the same.
 378   InstanceKlass* ik = SystemDictionary::find_instance_klass(THREAD, vmSymbols::java_lang_VersionProps(),
 379                                                             Handle(), Handle());
 380   {
 381     ResourceMark rm(main_thread);
 382     JDK_Version::set_java_version(get_java_version_info(ik, vmSymbols::java_version_name()));
 383 
 384     JDK_Version::set_runtime_name(get_java_version_info(ik, vmSymbols::java_runtime_name_name()));
 385 
 386     JDK_Version::set_runtime_version(get_java_version_info(ik, vmSymbols::java_runtime_version_name()));
 387 
 388     JDK_Version::set_runtime_vendor_version(get_java_version_info(ik, vmSymbols::java_runtime_vendor_version_name()));
 389 
 390     JDK_Version::set_runtime_vendor_vm_bug_url(get_java_version_info(ik, vmSymbols::java_runtime_vendor_vm_bug_url_name()));
 391   }
 392 
 393   // an instance of OutOfMemory exception has been allocated earlier
 394   initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
 395   initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
 396   initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
 397   initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
 398   initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
 399   initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
 400   initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
 401   initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
 402 }
 403 
 404 void Threads::initialize_jsr292_core_classes(TRAPS) {
 405   TraceTime timer("Initialize java.lang.invoke classes", TRACETIME_LOG(Info, startuptime));
 406 
 407   initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
 408   initialize_class(vmSymbols::java_lang_invoke_ResolvedMethodName(), CHECK);
 409   initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
 410   initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
 411 }
 412 
 413 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
 414   extern void JDK_Version_init();
 415 
 416   // Preinitialize version info.
 417   VM_Version::early_initialize();
 418 
 419   // Check version
 420   if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
 421 
 422   // Initialize library-based TLS
 423   ThreadLocalStorage::init();
 424 
 425   // Initialize the output stream module
 426   ostream_init();
 427 
 428   // Process java launcher properties.
 429   Arguments::process_sun_java_launcher_properties(args);
 430 
 431   // Initialize the os module
 432   os::init();
 433 
 434   MACOS_AARCH64_ONLY(os::current_thread_enable_wx(WXWrite));
 435 
 436   // Record VM creation timing statistics
 437   TraceVmCreationTime create_vm_timer;
 438   create_vm_timer.start();
 439 
 440   // Initialize system properties.
 441   Arguments::init_system_properties();
 442 
 443   // So that JDK version can be used as a discriminator when parsing arguments
 444   JDK_Version_init();
 445 
 446   // Update/Initialize System properties after JDK version number is known
 447   Arguments::init_version_specific_system_properties();
 448 
 449   // Make sure to initialize log configuration *before* parsing arguments
 450   LogConfiguration::initialize(create_vm_timer.begin_time());
 451 
 452   // Parse arguments
 453   // Note: this internally calls os::init_container_support()
 454   jint parse_result = Arguments::parse(args);
 455   if (parse_result != JNI_OK) return parse_result;
 456 
 457   // Initialize NMT right after argument parsing to keep the pre-NMT-init window small.
 458   MemTracker::initialize();
 459 
 460   os::init_before_ergo();
 461 
 462   jint ergo_result = Arguments::apply_ergo();
 463   if (ergo_result != JNI_OK) return ergo_result;
 464 
 465   // Final check of all ranges after ergonomics which may change values.
 466   if (!JVMFlagLimit::check_all_ranges()) {
 467     return JNI_EINVAL;
 468   }
 469 
 470   // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
 471   bool constraint_result = JVMFlagLimit::check_all_constraints(JVMFlagConstraintPhase::AfterErgo);
 472   if (!constraint_result) {
 473     return JNI_EINVAL;
 474   }
 475 
 476   if (PauseAtStartup) {
 477     os::pause();
 478   }
 479 
 480   HOTSPOT_VM_INIT_BEGIN();
 481 
 482   // Timing (must come after argument parsing)
 483   TraceTime timer("Create VM", TRACETIME_LOG(Info, startuptime));
 484 
 485   // Initialize the os module after parsing the args
 486   jint os_init_2_result = os::init_2();
 487   if (os_init_2_result != JNI_OK) return os_init_2_result;
 488 
 489 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT
 490   // Initialize assert poison page mechanism.
 491   if (ShowRegistersOnAssert) {
 492     initialize_assert_poison();
 493   }
 494 #endif // CAN_SHOW_REGISTERS_ON_ASSERT
 495 
 496   SafepointMechanism::initialize();
 497 
 498   jint adjust_after_os_result = Arguments::adjust_after_os();
 499   if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
 500 
 501   // Initialize output stream logging
 502   ostream_init_log();
 503 
 504   // Should happen before any agent attaches and pokes into vmStructs
 505 #if INCLUDE_VM_STRUCTS
 506   if (UseCompactObjectHeaders) {
 507     VMStructs::compact_headers_overrides();
 508   }
 509 #endif
 510 
 511   // Launch -agentlib/-agentpath and converted -Xrun agents
 512   JvmtiAgentList::load_agents();
 513 
 514   // Initialize Threads state
 515   _number_of_threads = 0;
 516   _number_of_non_daemon_threads = 0;
 517 
 518   // Initialize global data structures and create system classes in heap
 519   vm_init_globals();
 520 
 521 #if INCLUDE_JVMCI
 522   if (JVMCICounterSize > 0) {
 523     JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtJVMCI);
 524     memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize);
 525   } else {
 526     JavaThread::_jvmci_old_thread_counters = nullptr;
 527   }
 528 #endif // INCLUDE_JVMCI
 529 
 530   // Initialize OopStorage for threadObj
 531   JavaThread::_thread_oop_storage = OopStorageSet::create_strong("Thread OopStorage", mtThread);
 532 
 533   // Attach the main thread to this os thread
 534   JavaThread* main_thread = new JavaThread();
 535   main_thread->set_thread_state(_thread_in_vm);
 536   main_thread->initialize_thread_current();
 537   // must do this before set_active_handles
 538   main_thread->record_stack_base_and_size();
 539   main_thread->register_thread_stack_with_NMT();
 540   main_thread->set_active_handles(JNIHandleBlock::allocate_block());
 541   MACOS_AARCH64_ONLY(main_thread->init_wx());
 542 
 543   if (!main_thread->set_as_starting_thread()) {
 544     vm_shutdown_during_initialization(
 545                                       "Failed necessary internal allocation. Out of swap space");
 546     main_thread->smr_delete();
 547     *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
 548     return JNI_ENOMEM;
 549   }
 550 
 551   // Enable guard page *after* os::create_main_thread(), otherwise it would
 552   // crash Linux VM, see notes in os_linux.cpp.
 553   main_thread->stack_overflow_state()->create_stack_guard_pages();
 554 
 555   // Initialize Java-Level synchronization subsystem
 556   ObjectMonitor::Initialize();
 557   ObjectSynchronizer::initialize();
 558 
 559   // Initialize global modules
 560   jint status = init_globals();
 561   if (status != JNI_OK) {
 562     main_thread->smr_delete();
 563     *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
 564     return status;
 565   }
 566 
 567   // Create WatcherThread as soon as we can since we need it in case
 568   // of hangs during error reporting.
 569   WatcherThread::start();
 570 
 571   // Add main_thread to threads list to finish barrier setup with
 572   // on_thread_attach.  Should be before starting to build Java objects in
 573   // init_globals2, which invokes barriers.
 574   {
 575     MutexLocker mu(Threads_lock);
 576     Threads::add(main_thread);
 577   }
 578 
 579   status = init_globals2();
 580   if (status != JNI_OK) {
 581     Threads::remove(main_thread, false);
 582     // It is possible that we managed to fully initialize Universe but have then
 583     // failed by throwing an exception. In that case our caller JNI_CreateJavaVM
 584     // will want to report it, so we can't delete the main thread.
 585     if (!main_thread->has_pending_exception()) {
 586       main_thread->smr_delete();
 587     }
 588     *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
 589     return status;
 590   }
 591 
 592   JFR_ONLY(Jfr::on_create_vm_1();)
 593 
 594   // Should be done after the heap is fully created
 595   main_thread->cache_global_variables();
 596 
 597   // Any JVMTI raw monitors entered in onload will transition into
 598   // real raw monitor. VM is setup enough here for raw monitor enter.
 599   JvmtiExport::transition_pending_onload_raw_monitors();
 600 
 601   // Create the VMThread
 602   { TraceTime timer("Start VMThread", TRACETIME_LOG(Info, startuptime));
 603 
 604     VMThread::create();
 605     VMThread* vmthread = VMThread::vm_thread();
 606 
 607     if (!os::create_thread(vmthread, os::vm_thread)) {
 608       vm_exit_during_initialization("Cannot create VM thread. "
 609                                     "Out of system resources.");
 610     }
 611 
 612     // Wait for the VM thread to become ready, and VMThread::run to initialize
 613     // Monitors can have spurious returns, must always check another state flag
 614     {
 615       MonitorLocker ml(Notify_lock);
 616       os::start_thread(vmthread);
 617       while (!vmthread->is_running()) {
 618         ml.wait();
 619       }
 620     }
 621   }
 622 
 623   assert(Universe::is_fully_initialized(), "not initialized");
 624   if (VerifyDuringStartup) {
 625     // Make sure we're starting with a clean slate.
 626     VM_Verify verify_op;
 627     VMThread::execute(&verify_op);
 628   }
 629 
 630   // We need this to update the java.vm.info property in case any flags used
 631   // to initially define it have been changed. This is needed for both CDS
 632   // since UseSharedSpaces may be changed after java.vm.info
 633   // is initially computed. See Abstract_VM_Version::vm_info_string().
 634   // This update must happen before we initialize the java classes, but
 635   // after any initialization logic that might modify the flags.
 636   Arguments::update_vm_info_property(VM_Version::vm_info_string());
 637 
 638   JavaThread* THREAD = JavaThread::current(); // For exception macros.
 639   HandleMark hm(THREAD);
 640 
 641   // Always call even when there are not JVMTI environments yet, since environments
 642   // may be attached late and JVMTI must track phases of VM execution
 643   JvmtiExport::enter_early_start_phase();
 644 
 645   // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
 646   JvmtiExport::post_early_vm_start();
 647 
 648   // Launch -Xrun agents early if EagerXrunInit is set
 649   if (EagerXrunInit) {
 650     JvmtiAgentList::load_xrun_agents();
 651   }
 652 
 653   initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
 654 
 655   quicken_jni_functions();
 656 
 657   // No more stub generation allowed after that point.
 658   StubCodeDesc::freeze();
 659 
 660   // Set flag that basic initialization has completed. Used by exceptions and various
 661   // debug stuff, that does not work until all basic classes have been initialized.
 662   set_init_completed();
 663 
 664   LogConfiguration::post_initialize();
 665   Metaspace::post_initialize();
 666   MutexLocker::post_initialize();
 667 
 668   HOTSPOT_VM_INIT_END();
 669 
 670   // record VM initialization completion time
 671 #if INCLUDE_MANAGEMENT
 672   Management::record_vm_init_completed();
 673 #endif // INCLUDE_MANAGEMENT
 674 
 675   log_info(os)("Initialized VM with process ID %d", os::current_process_id());
 676 
 677   // Signal Dispatcher needs to be started before VMInit event is posted
 678   os::initialize_jdk_signal_support(CHECK_JNI_ERR);
 679 
 680   // Start Attach Listener if +StartAttachListener or it can't be started lazily
 681   if (!DisableAttachMechanism) {
 682     AttachListener::vm_start();
 683     if (StartAttachListener || AttachListener::init_at_startup()) {
 684       AttachListener::init();
 685     }
 686   }
 687 
 688   // Launch -Xrun agents if EagerXrunInit is not set.
 689   if (!EagerXrunInit) {
 690     JvmtiAgentList::load_xrun_agents();
 691   }
 692 
 693   Arena::start_chunk_pool_cleaner_task();
 694 
 695   // Start the service thread
 696   // The service thread enqueues JVMTI deferred events and does various hashtable
 697   // and other cleanups.  Needs to start before the compilers start posting events.
 698   ServiceThread::initialize();
 699 
 700   // Start the monitor deflation thread:
 701   MonitorDeflationThread::initialize();
 702 
 703   // initialize compiler(s)
 704 #if defined(COMPILER1) || COMPILER2_OR_JVMCI
 705 #if INCLUDE_JVMCI
 706   bool force_JVMCI_intialization = false;
 707   if (EnableJVMCI) {
 708     // Initialize JVMCI eagerly when it is explicitly requested.
 709     // Or when JVMCILibDumpJNIConfig or JVMCIPrintProperties is enabled.
 710     force_JVMCI_intialization = EagerJVMCI || JVMCIPrintProperties || JVMCILibDumpJNIConfig;
 711 
 712     if (!force_JVMCI_intialization) {
 713       // 8145270: Force initialization of JVMCI runtime otherwise requests for blocking
 714       // compilations via JVMCI will not actually block until JVMCI is initialized.
 715       force_JVMCI_intialization = UseJVMCICompiler && (!UseInterpreter || !BackgroundCompilation);
 716     }
 717   }
 718 #endif
 719   CompileBroker::compilation_init_phase1(CHECK_JNI_ERR);
 720   // Postpone completion of compiler initialization to after JVMCI
 721   // is initialized to avoid timeouts of blocking compilations.
 722   if (JVMCI_ONLY(!force_JVMCI_intialization) NOT_JVMCI(true)) {
 723     CompileBroker::compilation_init_phase2();
 724   }
 725 #endif
 726 
 727   // Start string deduplication thread if requested.
 728   if (StringDedup::is_enabled()) {
 729     StringDedup::start();
 730   }
 731 
 732   // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
 733   // It is done after compilers are initialized, because otherwise compilations of
 734   // signature polymorphic MH intrinsics can be missed
 735   // (see SystemDictionary::find_method_handle_intrinsic).
 736   initialize_jsr292_core_classes(CHECK_JNI_ERR);
 737 
 738   // This will initialize the module system.  Only java.base classes can be
 739   // loaded until phase 2 completes
 740   call_initPhase2(CHECK_JNI_ERR);
 741 
 742   JFR_ONLY(Jfr::on_create_vm_2();)
 743 
 744   // Always call even when there are not JVMTI environments yet, since environments
 745   // may be attached late and JVMTI must track phases of VM execution
 746   JvmtiExport::enter_start_phase();
 747 
 748   // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
 749   JvmtiExport::post_vm_start();
 750 
 751   // Final system initialization including security manager and system class loader
 752   call_initPhase3(CHECK_JNI_ERR);
 753 
 754   // cache the system and platform class loaders
 755   SystemDictionary::compute_java_loaders(CHECK_JNI_ERR);
 756 
 757 #if INCLUDE_CDS
 758   // capture the module path info from the ModuleEntryTable
 759   ClassLoader::initialize_module_path(THREAD);
 760   if (HAS_PENDING_EXCEPTION) {
 761     java_lang_Throwable::print(PENDING_EXCEPTION, tty);
 762     vm_exit_during_initialization("ClassLoader::initialize_module_path() failed unexpectedly");
 763   }
 764 #endif
 765 
 766 #if INCLUDE_JVMCI
 767   if (force_JVMCI_intialization) {
 768     JVMCI::initialize_compiler(CHECK_JNI_ERR);
 769     CompileBroker::compilation_init_phase2();
 770   }
 771 #endif
 772 
 773   if (NativeHeapTrimmer::enabled()) {
 774     NativeHeapTrimmer::initialize();
 775   }
 776 
 777   // Always call even when there are not JVMTI environments yet, since environments
 778   // may be attached late and JVMTI must track phases of VM execution
 779   JvmtiExport::enter_live_phase();
 780 
 781   // Make perfmemory accessible
 782   PerfMemory::set_accessible(true);
 783 
 784   // Notify JVMTI agents that VM initialization is complete - nop if no agents.
 785   JvmtiExport::post_vm_initialized();
 786 
 787   JFR_ONLY(Jfr::on_create_vm_3();)
 788 
 789 #if INCLUDE_MANAGEMENT
 790   Management::initialize(THREAD);
 791 
 792   if (HAS_PENDING_EXCEPTION) {
 793     // management agent fails to start possibly due to
 794     // configuration problem and is responsible for printing
 795     // stack trace if appropriate. Simply exit VM.
 796     vm_exit(1);
 797   }
 798 #endif // INCLUDE_MANAGEMENT
 799 
 800   StatSampler::engage();
 801   if (CheckJNICalls)                  JniPeriodicChecker::engage();
 802 
 803 #if INCLUDE_RTM_OPT
 804   RTMLockingCounters::init();
 805 #endif
 806 
 807   call_postVMInitHook(THREAD);
 808   // The Java side of PostVMInitHook.run must deal with all
 809   // exceptions and provide means of diagnosis.
 810   if (HAS_PENDING_EXCEPTION) {
 811     CLEAR_PENDING_EXCEPTION;
 812   }
 813 
 814   // Let WatcherThread run all registered periodic tasks now.
 815   // NOTE:  All PeriodicTasks should be registered by now. If they
 816   //   aren't, late joiners might appear to start slowly (we might
 817   //   take a while to process their first tick).
 818   WatcherThread::run_all_tasks();
 819 
 820   create_vm_timer.end();
 821 #ifdef ASSERT
 822   _vm_complete = true;
 823 #endif
 824 
 825   if (DumpSharedSpaces) {
 826     MetaspaceShared::preload_and_dump();
 827   }
 828 
 829   return JNI_OK;
 830 }
 831 
 832 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
 833 // the program falls off the end of main(). Another VM exit path is through
 834 // vm_exit() when the program calls System.exit() to return a value or when
 835 // there is a serious error in VM. The two shutdown paths are not exactly
 836 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
 837 // and VM_Exit op at VM level.
 838 //
 839 // Shutdown sequence:
 840 //   + Shutdown native memory tracking if it is on
 841 //   + Wait until we are the last non-daemon thread to execute
 842 //     <-- every thing is still working at this moment -->
 843 //   + Call java.lang.Shutdown.shutdown(), which will invoke Java level
 844 //        shutdown hooks
 845 //   + Call before_exit(), prepare for VM exit
 846 //      > run VM level shutdown hooks (they are registered through JVM_OnExit(),
 847 //        currently the only user of this mechanism is File.deleteOnExit())
 848 //      > stop StatSampler, watcher thread,
 849 //        post thread end and vm death events to JVMTI,
 850 //        stop signal thread
 851 //   + Call JavaThread::exit(), it will:
 852 //      > release JNI handle blocks, remove stack guard pages
 853 //      > remove this thread from Threads list
 854 //     <-- no more Java code from this thread after this point -->
 855 //   + Stop VM thread, it will bring the remaining VM to a safepoint and stop
 856 //     the compiler threads at safepoint
 857 //     <-- do not use anything that could get blocked by Safepoint -->
 858 //   + Disable tracing at JNI/JVM barriers
 859 //   + Set _vm_exited flag for threads that are still running native code
 860 //   + Call exit_globals()
 861 //      > deletes tty
 862 //      > deletes PerfMemory resources
 863 //   + Delete this thread
 864 //   + Return to caller
 865 
 866 void Threads::destroy_vm() {
 867   JavaThread* thread = JavaThread::current();
 868 
 869 #ifdef ASSERT
 870   _vm_complete = false;
 871 #endif
 872   // Wait until we are the last non-daemon thread to execute, or
 873   // if we are a daemon then wait until the last non-daemon thread has
 874   // executed.
 875   bool daemon = java_lang_Thread::is_daemon(thread->threadObj());
 876   int expected = daemon ? 0 : 1;
 877   {
 878     MonitorLocker nu(Threads_lock);
 879     while (Threads::number_of_non_daemon_threads() > expected)
 880       // This wait should make safepoint checks, wait without a timeout.
 881       nu.wait(0);
 882   }
 883 
 884   EventShutdown e;
 885   if (e.should_commit()) {
 886     e.set_reason("No remaining non-daemon Java threads");
 887     e.commit();
 888   }
 889 
 890   // Hang forever on exit if we are reporting an error.
 891   if (ShowMessageBoxOnError && VMError::is_error_reported()) {
 892     os::infinite_sleep();
 893   }
 894   os::wait_for_keypress_at_exit();
 895 
 896   // run Java level shutdown hooks
 897   thread->invoke_shutdown_hooks();
 898 
 899   before_exit(thread);
 900 
 901   thread->exit(true);
 902 
 903   // We are no longer on the main thread list but could still be in a
 904   // secondary list where another thread may try to interact with us.
 905   // So wait until all such interactions are complete before we bring
 906   // the VM to the termination safepoint. Normally this would be done
 907   // using thread->smr_delete() below where we delete the thread, but
 908   // we can't call that after the termination safepoint is active as
 909   // we will deadlock on the Threads_lock. Once all interactions are
 910   // complete it is safe to directly delete the thread at any time.
 911   ThreadsSMRSupport::wait_until_not_protected(thread);
 912 
 913   // Stop VM thread.
 914   {
 915     // 4945125 The vm thread comes to a safepoint during exit.
 916     // GC vm_operations can get caught at the safepoint, and the
 917     // heap is unparseable if they are caught. Grab the Heap_lock
 918     // to prevent this. The GC vm_operations will not be able to
 919     // queue until after the vm thread is dead. After this point,
 920     // we'll never emerge out of the safepoint before the VM exits.
 921     // Assert that the thread is terminated so that acquiring the
 922     // Heap_lock doesn't cause the terminated thread to participate in
 923     // the safepoint protocol.
 924 
 925     assert(thread->is_terminated(), "must be terminated here");
 926     MutexLocker ml(Heap_lock);
 927 
 928     VMThread::wait_for_vm_thread_exit();
 929     assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
 930     VMThread::destroy();
 931   }
 932 
 933   // Now, all Java threads are gone except daemon threads. Daemon threads
 934   // running Java code or in VM are stopped by the Safepoint. However,
 935   // daemon threads executing native code are still running.  But they
 936   // will be stopped at native=>Java/VM barriers. Note that we can't
 937   // simply kill or suspend them, as it is inherently deadlock-prone.
 938 
 939   VM_Exit::set_vm_exited();
 940 
 941   // Clean up ideal graph printers after the VMThread has started
 942   // the final safepoint which will block all the Compiler threads.
 943   // Note that this Thread has already logically exited so the
 944   // clean_up() function's use of a JavaThreadIteratorWithHandle
 945   // would be a problem except set_vm_exited() has remembered the
 946   // shutdown thread which is granted a policy exception.
 947 #if defined(COMPILER2) && !defined(PRODUCT)
 948   IdealGraphPrinter::clean_up();
 949 #endif
 950 
 951   notify_vm_shutdown();
 952 
 953   // exit_globals() will delete tty
 954   exit_globals();
 955 
 956   // Deleting the shutdown thread here is safe. See comment on
 957   // wait_until_not_protected() above.
 958   delete thread;
 959 
 960 #if INCLUDE_JVMCI
 961   if (JVMCICounterSize > 0) {
 962     FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters);
 963   }
 964 #endif
 965 
 966   LogConfiguration::finalize();
 967 }
 968 
 969 
 970 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
 971   if (version == JNI_VERSION_1_1) return JNI_TRUE;
 972   return is_supported_jni_version(version);
 973 }
 974 
 975 
 976 jboolean Threads::is_supported_jni_version(jint version) {
 977   if (version == JNI_VERSION_1_2) return JNI_TRUE;
 978   if (version == JNI_VERSION_1_4) return JNI_TRUE;
 979   if (version == JNI_VERSION_1_6) return JNI_TRUE;
 980   if (version == JNI_VERSION_1_8) return JNI_TRUE;
 981   if (version == JNI_VERSION_9) return JNI_TRUE;
 982   if (version == JNI_VERSION_10) return JNI_TRUE;
 983   if (version == JNI_VERSION_19) return JNI_TRUE;
 984   if (version == JNI_VERSION_20) return JNI_TRUE;
 985   if (version == JNI_VERSION_21) return JNI_TRUE;
 986   return JNI_FALSE;
 987 }
 988 
 989 void Threads::add(JavaThread* p, bool force_daemon) {
 990   // The threads lock must be owned at this point
 991   assert(Threads_lock->owned_by_self(), "must have threads lock");
 992 
 993   BarrierSet::barrier_set()->on_thread_attach(p);
 994 
 995   // Once a JavaThread is added to the Threads list, smr_delete() has
 996   // to be used to delete it. Otherwise we can just delete it directly.
 997   p->set_on_thread_list();
 998 
 999   _number_of_threads++;
1000   oop threadObj = p->threadObj();
1001   bool daemon = true;
1002   // Bootstrapping problem: threadObj can be null for initial
1003   // JavaThread (or for threads attached via JNI)
1004   if (!force_daemon &&
1005       (threadObj == nullptr || !java_lang_Thread::is_daemon(threadObj))) {
1006     _number_of_non_daemon_threads++;
1007     daemon = false;
1008   }
1009 
1010   ThreadService::add_thread(p, daemon);
1011 
1012   // Maintain fast thread list
1013   ThreadsSMRSupport::add_thread(p);
1014 
1015   // Increase the ObjectMonitor ceiling for the new thread.
1016   ObjectSynchronizer::inc_in_use_list_ceiling();
1017 
1018   // Possible GC point.
1019   Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p));
1020 
1021   // Make new thread known to active EscapeBarrier
1022   EscapeBarrier::thread_added(p);
1023 }
1024 
1025 void Threads::remove(JavaThread* p, bool is_daemon) {
1026   // Extra scope needed for Thread_lock, so we can check
1027   // that we do not remove thread without safepoint code notice
1028   { MonitorLocker ml(Threads_lock);
1029 
1030     if (ThreadIdTable::is_initialized()) {
1031       // This cleanup must be done before the current thread's GC barrier
1032       // is detached since we need to touch the threadObj oop.
1033       jlong tid = SharedRuntime::get_java_tid(p);
1034       ThreadIdTable::remove_thread(tid);
1035     }
1036 
1037     // BarrierSet state must be destroyed after the last thread transition
1038     // before the thread terminates. Thread transitions result in calls to
1039     // StackWatermarkSet::on_safepoint(), which performs GC processing,
1040     // requiring the GC state to be alive.
1041     BarrierSet::barrier_set()->on_thread_detach(p);
1042     if (p->is_exiting()) {
1043       // If we got here via JavaThread::exit(), then we remember that the
1044       // thread's GC barrier has been detached. We don't do this when we get
1045       // here from another path, e.g., cleanup_failed_attach_current_thread().
1046       p->set_terminated(JavaThread::_thread_gc_barrier_detached);
1047     }
1048 
1049     assert(ThreadsSMRSupport::get_java_thread_list()->includes(p), "p must be present");
1050 
1051     // Maintain fast thread list
1052     ThreadsSMRSupport::remove_thread(p);
1053 
1054     _number_of_threads--;
1055     if (!is_daemon) {
1056       _number_of_non_daemon_threads--;
1057 
1058       // If this is the last non-daemon thread then we need to do
1059       // a notify on the Threads_lock so a thread waiting
1060       // on destroy_vm will wake up. But that thread could be a daemon
1061       // or non-daemon, so we notify for both the 0 and 1 case.
1062       if (number_of_non_daemon_threads() <= 1) {
1063         ml.notify_all();
1064       }
1065     }
1066     ThreadService::remove_thread(p, is_daemon);
1067 
1068     // Make sure that safepoint code disregard this thread. This is needed since
1069     // the thread might mess around with locks after this point. This can cause it
1070     // to do callbacks into the safepoint code. However, the safepoint code is not aware
1071     // of this thread since it is removed from the queue.
1072     p->set_terminated(JavaThread::_thread_terminated);
1073 
1074     // Notify threads waiting in EscapeBarriers
1075     EscapeBarrier::thread_removed(p);
1076   } // unlock Threads_lock
1077 
1078   // Reduce the ObjectMonitor ceiling for the exiting thread.
1079   ObjectSynchronizer::dec_in_use_list_ceiling();
1080 
1081   // Since Events::log uses a lock, we grab it outside the Threads_lock
1082   Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p));
1083 }
1084 
1085 // Operations on the Threads list for GC.  These are not explicitly locked,
1086 // but the garbage collector must provide a safe context for them to run.
1087 // In particular, these things should never be called when the Threads_lock
1088 // is held by some other thread. (Note: the Safepoint abstraction also
1089 // uses the Threads_lock to guarantee this property. It also makes sure that
1090 // all threads gets blocked when exiting or starting).
1091 
1092 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) {
1093   ALL_JAVA_THREADS(p) {
1094     p->oops_do(f, cf);
1095   }
1096   VMThread::vm_thread()->oops_do(f, cf);
1097 }
1098 
1099 void Threads::change_thread_claim_token() {
1100   if (++_thread_claim_token == 0) {
1101     // On overflow of the token counter, there is a risk of future
1102     // collisions between a new global token value and a stale token
1103     // for a thread, because not all iterations visit all threads.
1104     // (Though it's pretty much a theoretical concern for non-trivial
1105     // token counter sizes.)  To deal with the possibility, reset all
1106     // the thread tokens to zero on global token overflow.
1107     struct ResetClaims : public ThreadClosure {
1108       virtual void do_thread(Thread* t) {
1109         t->claim_threads_do(false, 0);
1110       }
1111     } reset_claims;
1112     Threads::threads_do(&reset_claims);
1113     // On overflow, update the global token to non-zero, to
1114     // avoid the special "never claimed" initial thread value.
1115     _thread_claim_token = 1;
1116   }
1117 }
1118 
1119 #ifdef ASSERT
1120 void assert_thread_claimed(const char* kind, Thread* t, uintx expected) {
1121   const uintx token = t->threads_do_token();
1122   assert(token == expected,
1123          "%s " PTR_FORMAT " has incorrect value " UINTX_FORMAT " != "
1124          UINTX_FORMAT, kind, p2i(t), token, expected);
1125 }
1126 
1127 void Threads::assert_all_threads_claimed() {
1128   ALL_JAVA_THREADS(p) {
1129     assert_thread_claimed("JavaThread", p, _thread_claim_token);
1130   }
1131 
1132   struct NJTClaimedVerifierClosure : public ThreadClosure {
1133     uintx _thread_claim_token;
1134 
1135     NJTClaimedVerifierClosure(uintx thread_claim_token) : ThreadClosure(), _thread_claim_token(thread_claim_token) { }
1136 
1137     virtual void do_thread(Thread* thread) override {
1138       assert_thread_claimed("Non-JavaThread", VMThread::vm_thread(), _thread_claim_token);
1139     }
1140   } tc(_thread_claim_token);
1141 
1142   non_java_threads_do(&tc);
1143 }
1144 #endif // ASSERT
1145 
1146 class ParallelOopsDoThreadClosure : public ThreadClosure {
1147 private:
1148   OopClosure* _f;
1149   CodeBlobClosure* _cf;
1150 public:
1151   ParallelOopsDoThreadClosure(OopClosure* f, CodeBlobClosure* cf) : _f(f), _cf(cf) {}
1152   void do_thread(Thread* t) {
1153     t->oops_do(_f, _cf);
1154   }
1155 };
1156 
1157 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf) {
1158   ParallelOopsDoThreadClosure tc(f, cf);
1159   possibly_parallel_threads_do(is_par, &tc);
1160 }
1161 
1162 void Threads::metadata_do(MetadataClosure* f) {
1163   ALL_JAVA_THREADS(p) {
1164     p->metadata_do(f);
1165   }
1166 }
1167 
1168 class ThreadHandlesClosure : public ThreadClosure {
1169   void (*_f)(Metadata*);
1170  public:
1171   ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
1172   virtual void do_thread(Thread* thread) {
1173     thread->metadata_handles_do(_f);
1174   }
1175 };
1176 
1177 void Threads::metadata_handles_do(void f(Metadata*)) {
1178   // Only walk the Handles in Thread.
1179   ThreadHandlesClosure handles_closure(f);
1180   threads_do(&handles_closure);
1181 }
1182 
1183 // Get count Java threads that are waiting to enter the specified monitor.
1184 GrowableArray<JavaThread*>* Threads::get_pending_threads(ThreadsList * t_list,
1185                                                          int count,
1186                                                          address monitor) {
1187   GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
1188 
1189   int i = 0;
1190   for (JavaThread* p : *t_list) {
1191     if (!p->can_call_java()) continue;
1192 
1193     // The first stage of async deflation does not affect any field
1194     // used by this comparison so the ObjectMonitor* is usable here.
1195     address pending = (address)p->current_pending_monitor();
1196     if (pending == monitor) {             // found a match
1197       if (i < count) result->append(p);   // save the first count matches
1198       i++;
1199     }
1200   }
1201 
1202   return result;
1203 }
1204 
1205 
1206 JavaThread *Threads::owning_thread_from_monitor_owner(ThreadsList * t_list,
1207                                                       address owner) {
1208   assert(LockingMode != LM_LIGHTWEIGHT, "Not with new lightweight locking");
1209   // null owner means not locked so we can skip the search
1210   if (owner == nullptr) return nullptr;
1211 
1212   for (JavaThread* p : *t_list) {
1213     // first, see if owner is the address of a Java thread
1214     if (owner == (address)p) return p;
1215   }
1216 
1217   // Cannot assert on lack of success here since this function may be
1218   // used by code that is trying to report useful problem information
1219   // like deadlock detection.
1220   if (LockingMode == LM_MONITOR) return nullptr;
1221 
1222   // If we didn't find a matching Java thread and we didn't force use of
1223   // heavyweight monitors, then the owner is the stack address of the
1224   // Lock Word in the owning Java thread's stack.
1225   //
1226   JavaThread* the_owner = nullptr;
1227   for (JavaThread* q : *t_list) {
1228     if (q->is_lock_owned(owner)) {
1229       the_owner = q;
1230       break;
1231     }
1232   }
1233 
1234   // cannot assert on lack of success here; see above comment
1235   return the_owner;
1236 }
1237 
1238 JavaThread* Threads::owning_thread_from_object(ThreadsList * t_list, oop obj) {
1239   assert(LockingMode == LM_LIGHTWEIGHT, "Only with new lightweight locking");
1240   for (JavaThread* q : *t_list) {
1241     if (q->lock_stack().contains(obj)) {
1242       return q;
1243     }
1244   }
1245   return nullptr;
1246 }
1247 
1248 JavaThread* Threads::owning_thread_from_monitor(ThreadsList* t_list, ObjectMonitor* monitor) {
1249   if (LockingMode == LM_LIGHTWEIGHT) {
1250     if (monitor->is_owner_anonymous()) {
1251       return owning_thread_from_object(t_list, monitor->object());
1252     } else {
1253       Thread* owner = reinterpret_cast<Thread*>(monitor->owner());
1254       assert(owner == nullptr || owner->is_Java_thread(), "only JavaThreads own monitors");
1255       return reinterpret_cast<JavaThread*>(owner);
1256     }
1257   } else {
1258     address owner = (address)monitor->owner();
1259     return owning_thread_from_monitor_owner(t_list, owner);
1260   }
1261 }
1262 
1263 class PrintOnClosure : public ThreadClosure {
1264 private:
1265   outputStream* _st;
1266 
1267 public:
1268   PrintOnClosure(outputStream* st) :
1269       _st(st) {}
1270 
1271   virtual void do_thread(Thread* thread) {
1272     if (thread != nullptr) {
1273       thread->print_on(_st);
1274       _st->cr();
1275     }
1276   }
1277 };
1278 
1279 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
1280 void Threads::print_on(outputStream* st, bool print_stacks,
1281                        bool internal_format, bool print_concurrent_locks,
1282                        bool print_extended_info) {
1283   char buf[32];
1284   st->print_raw_cr(os::local_time_string(buf, sizeof(buf)));
1285 
1286   st->print_cr("Full thread dump %s (%s %s):",
1287                VM_Version::vm_name(),
1288                VM_Version::vm_release(),
1289                VM_Version::vm_info_string());
1290   st->cr();
1291 
1292 #if INCLUDE_SERVICES
1293   // Dump concurrent locks
1294   ConcurrentLocksDump concurrent_locks;
1295   if (print_concurrent_locks) {
1296     concurrent_locks.dump_at_safepoint();
1297   }
1298 #endif // INCLUDE_SERVICES
1299 
1300   ThreadsSMRSupport::print_info_on(st);
1301   st->cr();
1302 
1303   ALL_JAVA_THREADS(p) {
1304     ResourceMark rm;
1305     p->print_on(st, print_extended_info);
1306     if (print_stacks) {
1307       if (internal_format) {
1308         p->trace_stack();
1309       } else {
1310         p->print_stack_on(st);
1311       }
1312     }
1313     st->cr();
1314 #if INCLUDE_SERVICES
1315     if (print_concurrent_locks) {
1316       concurrent_locks.print_locks_on(p, st);
1317     }
1318 #endif // INCLUDE_SERVICES
1319   }
1320 
1321   PrintOnClosure cl(st);
1322   cl.do_thread(VMThread::vm_thread());
1323   Universe::heap()->gc_threads_do(&cl);
1324   cl.do_thread(WatcherThread::watcher_thread());
1325   cl.do_thread(AsyncLogWriter::instance());
1326 
1327   st->flush();
1328 }
1329 
1330 void Threads::print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
1331                              int buflen, bool* found_current) {
1332   if (this_thread != nullptr) {
1333     bool is_current = (current == this_thread);
1334     *found_current = *found_current || is_current;
1335     st->print("%s", is_current ? "=>" : "  ");
1336 
1337     st->print(PTR_FORMAT, p2i(this_thread));
1338     st->print(" ");
1339     this_thread->print_on_error(st, buf, buflen);
1340     st->cr();
1341   }
1342 }
1343 
1344 class PrintOnErrorClosure : public ThreadClosure {
1345   outputStream* _st;
1346   Thread* _current;
1347   char* _buf;
1348   int _buflen;
1349   bool* _found_current;
1350   unsigned _num_printed;
1351  public:
1352   PrintOnErrorClosure(outputStream* st, Thread* current, char* buf,
1353                       int buflen, bool* found_current) :
1354    _st(st), _current(current), _buf(buf), _buflen(buflen), _found_current(found_current),
1355    _num_printed(0) {}
1356 
1357   virtual void do_thread(Thread* thread) {
1358     _num_printed++;
1359     Threads::print_on_error(thread, _st, _current, _buf, _buflen, _found_current);
1360   }
1361 
1362   unsigned num_printed() const { return _num_printed; }
1363 };
1364 
1365 // Threads::print_on_error() is called by fatal error handler. It's possible
1366 // that VM is not at safepoint and/or current thread is inside signal handler.
1367 // Don't print stack trace, as the stack may not be walkable. Don't allocate
1368 // memory (even in resource area), it might deadlock the error handler.
1369 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
1370                              int buflen) {
1371   ThreadsSMRSupport::print_info_on(st);
1372   st->cr();
1373 
1374   bool found_current = false;
1375   st->print_cr("Java Threads: ( => current thread )");
1376   unsigned num_java = 0;
1377   ALL_JAVA_THREADS(thread) {
1378     print_on_error(thread, st, current, buf, buflen, &found_current);
1379     num_java++;
1380   }
1381   st->print_cr("Total: %u", num_java);
1382   st->cr();
1383 
1384   st->print_cr("Other Threads:");
1385   unsigned num_other = ((VMThread::vm_thread() != nullptr) ? 1 : 0) +
1386       ((WatcherThread::watcher_thread() != nullptr) ? 1 : 0) +
1387       ((AsyncLogWriter::instance() != nullptr)  ? 1 : 0);
1388   print_on_error(VMThread::vm_thread(), st, current, buf, buflen, &found_current);
1389   print_on_error(WatcherThread::watcher_thread(), st, current, buf, buflen, &found_current);
1390   print_on_error(AsyncLogWriter::instance(), st, current, buf, buflen, &found_current);
1391 
1392   if (Universe::heap() != nullptr) {
1393     PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current);
1394     Universe::heap()->gc_threads_do(&print_closure);
1395     num_other += print_closure.num_printed();
1396   }
1397 
1398   if (!found_current) {
1399     st->cr();
1400     st->print("=>" PTR_FORMAT " (exited) ", p2i(current));
1401     current->print_on_error(st, buf, buflen);
1402     num_other++;
1403     st->cr();
1404   }
1405   st->print_cr("Total: %u", num_other);
1406   st->cr();
1407 
1408   st->print_cr("Threads with active compile tasks:");
1409   unsigned num = print_threads_compiling(st, buf, buflen);
1410   st->print_cr("Total: %u", num);
1411 }
1412 
1413 unsigned Threads::print_threads_compiling(outputStream* st, char* buf, int buflen, bool short_form) {
1414   unsigned num = 0;
1415   ALL_JAVA_THREADS(thread) {
1416     if (thread->is_Compiler_thread()) {
1417       CompilerThread* ct = (CompilerThread*) thread;
1418 
1419       // Keep task in local variable for null check.
1420       // ct->_task might be set to null by concurring compiler thread
1421       // because it completed the compilation. The task is never freed,
1422       // though, just returned to a free list.
1423       CompileTask* task = ct->task();
1424       if (task != nullptr) {
1425         thread->print_name_on_error(st, buf, buflen);
1426         st->print("  ");
1427         task->print(st, nullptr, short_form, true);
1428         num++;
1429       }
1430     }
1431   }
1432   return num;
1433 }
1434 
1435 void Threads::verify() {
1436   ALL_JAVA_THREADS(p) {
1437     p->verify();
1438   }
1439   VMThread* thread = VMThread::vm_thread();
1440   if (thread != nullptr) thread->verify();
1441 }