1 /*
   2  * Copyright (c) 1997, 2024, 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/cdsConfig.hpp"
  29 #include "cds/metaspaceShared.hpp"
  30 #include "classfile/classLoader.hpp"
  31 #include "classfile/javaClasses.hpp"
  32 #include "classfile/javaThreadStatus.hpp"
  33 #include "classfile/systemDictionary.hpp"
  34 #include "classfile/vmClasses.hpp"
  35 #include "classfile/vmSymbols.hpp"
  36 #include "compiler/compileBroker.hpp"
  37 #include "compiler/compileTask.hpp"
  38 #include "compiler/compilerThread.hpp"
  39 #include "gc/shared/barrierSet.hpp"
  40 #include "gc/shared/barrierSetNMethod.hpp"
  41 #include "gc/shared/gcVMOperations.hpp"
  42 #include "gc/shared/oopStorage.hpp"
  43 #include "gc/shared/oopStorageSet.hpp"
  44 #include "gc/shared/stringdedup/stringDedup.hpp"
  45 #include "jfr/jfrEvents.hpp"
  46 #include "jvm.h"
  47 #include "jvmtifiles/jvmtiEnv.hpp"
  48 #include "logging/log.hpp"
  49 #include "logging/logAsyncWriter.hpp"
  50 #include "logging/logConfiguration.hpp"
  51 #include "memory/allocation.inline.hpp"
  52 #include "memory/iterator.hpp"
  53 #include "memory/oopFactory.hpp"
  54 #include "memory/resourceArea.hpp"
  55 #include "memory/universe.hpp"
  56 #include "nmt/memTracker.hpp"
  57 #include "oops/instanceKlass.hpp"
  58 #include "oops/klass.inline.hpp"
  59 #include "oops/oop.inline.hpp"
  60 #include "oops/symbol.hpp"
  61 #include "prims/jvm_misc.hpp"
  62 #include "prims/jvmtiAgentList.hpp"
  63 #include "runtime/arguments.hpp"
  64 #include "runtime/fieldDescriptor.inline.hpp"
  65 #include "runtime/flags/jvmFlagLimit.hpp"
  66 #include "runtime/globals.hpp"
  67 #include "runtime/handles.inline.hpp"
  68 #include "runtime/interfaceSupport.inline.hpp"
  69 #include "runtime/java.hpp"
  70 #include "runtime/javaCalls.hpp"
  71 #include "runtime/javaThread.inline.hpp"
  72 #include "runtime/jniHandles.inline.hpp"
  73 #include "runtime/jniPeriodicChecker.hpp"
  74 #include "runtime/lockStack.inline.hpp"
  75 #include "runtime/monitorDeflationThread.hpp"
  76 #include "runtime/mutexLocker.hpp"
  77 #include "runtime/nonJavaThread.hpp"
  78 #include "runtime/objectMonitor.inline.hpp"
  79 #include "runtime/osThread.hpp"
  80 #include "runtime/safepoint.hpp"
  81 #include "runtime/safepointMechanism.inline.hpp"
  82 #include "runtime/safepointVerifiers.hpp"
  83 #include "runtime/serviceThread.hpp"
  84 #include "runtime/sharedRuntime.hpp"
  85 #include "runtime/stackWatermarkSet.inline.hpp"
  86 #include "runtime/statSampler.hpp"
  87 #include "runtime/stubCodeGenerator.hpp"
  88 #include "runtime/thread.inline.hpp"
  89 #include "runtime/threadSMR.inline.hpp"
  90 #include "runtime/threads.hpp"
  91 #include "runtime/timer.hpp"
  92 #include "runtime/timerTrace.hpp"
  93 #include "runtime/trimNativeHeap.hpp"
  94 #include "runtime/vmOperations.hpp"
  95 #include "runtime/vm_version.hpp"
  96 #include "services/attachListener.hpp"
  97 #include "services/management.hpp"
  98 #include "services/threadIdTable.hpp"
  99 #include "services/threadService.hpp"
 100 #include "utilities/dtrace.hpp"
 101 #include "utilities/events.hpp"
 102 #include "utilities/macros.hpp"
 103 #include "utilities/vmError.hpp"
 104 #if INCLUDE_JVMCI
 105 #include "jvmci/jvmci.hpp"
 106 #include "jvmci/jvmciEnv.hpp"
 107 #endif
 108 #ifdef COMPILER2
 109 #include "opto/idealGraphPrinter.hpp"
 110 #endif
 111 #if INCLUDE_RTM_OPT
 112 #include "runtime/rtmLocking.hpp"
 113 #endif
 114 #if INCLUDE_JFR
 115 #include "jfr/jfr.hpp"
 116 #endif
 117 #if INCLUDE_VM_STRUCTS
 118 #include "runtime/vmStructs.hpp"
 119 #endif
 120 
 121 // Initialization after module runtime initialization
 122 void universe_post_module_init();  // must happen after call_initPhase2
 123 
 124 
 125 static void initialize_class(Symbol* class_name, TRAPS) {
 126   Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
 127   InstanceKlass::cast(klass)->initialize(CHECK);
 128 }
 129 
 130 
 131 // Creates the initial ThreadGroup
 132 static Handle create_initial_thread_group(TRAPS) {
 133   Handle system_instance = JavaCalls::construct_new_instance(
 134                             vmClasses::ThreadGroup_klass(),
 135                             vmSymbols::void_method_signature(),
 136                             CHECK_NH);
 137   Universe::set_system_thread_group(system_instance());
 138 
 139   Handle string = java_lang_String::create_from_str("main", CHECK_NH);
 140   Handle main_instance = JavaCalls::construct_new_instance(
 141                             vmClasses::ThreadGroup_klass(),
 142                             vmSymbols::threadgroup_string_void_signature(),
 143                             system_instance,
 144                             string,
 145                             CHECK_NH);
 146   return main_instance;
 147 }
 148 
 149 // Creates the initial Thread, and sets it to running.
 150 static void create_initial_thread(Handle thread_group, JavaThread* thread,
 151                                  TRAPS) {
 152   InstanceKlass* ik = vmClasses::Thread_klass();
 153   assert(ik->is_initialized(), "must be");
 154   instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
 155 
 156   // Cannot use JavaCalls::construct_new_instance because the java.lang.Thread
 157   // constructor calls Thread.current(), which must be set here for the
 158   // initial thread.
 159   java_lang_Thread::set_thread(thread_oop(), thread);
 160   thread->set_threadOopHandles(thread_oop());
 161 
 162   Handle string = java_lang_String::create_from_str("main", CHECK);
 163 
 164   JavaValue result(T_VOID);
 165   JavaCalls::call_special(&result, thread_oop,
 166                           ik,
 167                           vmSymbols::object_initializer_name(),
 168                           vmSymbols::threadgroup_string_void_signature(),
 169                           thread_group,
 170                           string,
 171                           CHECK);
 172 
 173   // Set thread status to running since main thread has
 174   // been started and running.
 175   java_lang_Thread::set_thread_status(thread_oop(),
 176                                       JavaThreadStatus::RUNNABLE);
 177 }
 178 
 179 // Extract version and vendor specific information from
 180 // java.lang.VersionProps fields.
 181 // Returned char* is allocated in the thread's resource area
 182 // so must be copied for permanency.
 183 static const char* get_java_version_info(InstanceKlass* ik,
 184                                          Symbol* field_name) {
 185   fieldDescriptor fd;
 186   bool found = ik != nullptr &&
 187                ik->find_local_field(field_name,
 188                                     vmSymbols::string_signature(), &fd);
 189   if (found) {
 190     oop name_oop = ik->java_mirror()->obj_field(fd.offset());
 191     if (name_oop == nullptr) {
 192       return nullptr;
 193     }
 194     const char* name = java_lang_String::as_utf8_string(name_oop);
 195     return name;
 196   } else {
 197     return nullptr;
 198   }
 199 }
 200 
 201 // ======= Threads ========
 202 
 203 // The Threads class links together all active threads, and provides
 204 // operations over all threads. It is protected by the Threads_lock,
 205 // which is also used in other global contexts like safepointing.
 206 // ThreadsListHandles are used to safely perform operations on one
 207 // or more threads without the risk of the thread exiting during the
 208 // operation.
 209 //
 210 // Note: The Threads_lock is currently more widely used than we
 211 // would like. We are actively migrating Threads_lock uses to other
 212 // mechanisms in order to reduce Threads_lock contention.
 213 
 214 int         Threads::_number_of_threads = 0;
 215 int         Threads::_number_of_non_daemon_threads = 0;
 216 int         Threads::_return_code = 0;
 217 uintx       Threads::_thread_claim_token = 1; // Never zero.
 218 
 219 #ifdef ASSERT
 220 bool        Threads::_vm_complete = false;
 221 #endif
 222 
 223 // General purpose hook into Java code, run once when the VM is initialized.
 224 // The Java library method itself may be changed independently from the VM.
 225 static void call_postVMInitHook(TRAPS) {
 226   Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_vm_PostVMInitHook(), THREAD);
 227   if (klass != nullptr) {
 228     JavaValue result(T_VOID);
 229     JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
 230                            vmSymbols::void_method_signature(),
 231                            CHECK);
 232   }
 233 }
 234 
 235 // All NonJavaThreads (i.e., every non-JavaThread in the system).
 236 void Threads::non_java_threads_do(ThreadClosure* tc) {
 237   NoSafepointVerifier nsv;
 238   for (NonJavaThread::Iterator njti; !njti.end(); njti.step()) {
 239     tc->do_thread(njti.current());
 240   }
 241 }
 242 
 243 // All JavaThreads
 244 #define ALL_JAVA_THREADS(X) \
 245   for (JavaThread* X : *ThreadsSMRSupport::get_java_thread_list())
 246 
 247 // All JavaThreads
 248 void Threads::java_threads_do(ThreadClosure* tc) {
 249   assert_locked_or_safepoint(Threads_lock);
 250   // ALL_JAVA_THREADS iterates through all JavaThreads.
 251   ALL_JAVA_THREADS(p) {
 252     tc->do_thread(p);
 253   }
 254 }
 255 
 256 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system).
 257 void Threads::threads_do(ThreadClosure* tc) {
 258   assert_locked_or_safepoint(Threads_lock);
 259   java_threads_do(tc);
 260   non_java_threads_do(tc);
 261 }
 262 
 263 void Threads::possibly_parallel_threads_do(bool is_par, ThreadClosure* tc) {
 264   assert_at_safepoint();
 265 
 266   uintx claim_token = Threads::thread_claim_token();
 267   ALL_JAVA_THREADS(p) {
 268     if (p->claim_threads_do(is_par, claim_token)) {
 269       tc->do_thread(p);
 270     }
 271   }
 272   for (NonJavaThread::Iterator njti; !njti.end(); njti.step()) {
 273     Thread* current = njti.current();
 274     if (current->claim_threads_do(is_par, claim_token)) {
 275       tc->do_thread(current);
 276     }
 277   }
 278 }
 279 
 280 // The system initialization in the library has three phases.
 281 //
 282 // Phase 1: java.lang.System class initialization
 283 //     java.lang.System is a primordial class loaded and initialized
 284 //     by the VM early during startup.  java.lang.System.<clinit>
 285 //     only does registerNatives and keeps the rest of the class
 286 //     initialization work later until thread initialization completes.
 287 //
 288 //     System.initPhase1 initializes the system properties, the static
 289 //     fields in, out, and err. Set up java signal handlers, OS-specific
 290 //     system settings, and thread group of the main thread.
 291 static void call_initPhase1(TRAPS) {
 292   Klass* klass = vmClasses::System_klass();
 293   JavaValue result(T_VOID);
 294   JavaCalls::call_static(&result, klass, vmSymbols::initPhase1_name(),
 295                                          vmSymbols::void_method_signature(), CHECK);
 296 }
 297 
 298 // Phase 2. Module system initialization
 299 //     This will initialize the module system.  Only java.base classes
 300 //     can be loaded until phase 2 completes.
 301 //
 302 //     Call System.initPhase2 after the compiler initialization and jsr292
 303 //     classes get initialized because module initialization runs a lot of java
 304 //     code, that for performance reasons, should be compiled.  Also, this will
 305 //     enable the startup code to use lambda and other language features in this
 306 //     phase and onward.
 307 //
 308 //     After phase 2, The VM will begin search classes from -Xbootclasspath/a.
 309 static void call_initPhase2(TRAPS) {
 310   TraceTime timer("Initialize module system", TRACETIME_LOG(Info, startuptime));
 311 
 312   Klass* klass = vmClasses::System_klass();
 313 
 314   JavaValue result(T_INT);
 315   JavaCallArguments args;
 316   args.push_int(DisplayVMOutputToStderr);
 317   args.push_int(log_is_enabled(Debug, init)); // print stack trace if exception thrown
 318   JavaCalls::call_static(&result, klass, vmSymbols::initPhase2_name(),
 319                                          vmSymbols::boolean_boolean_int_signature(), &args, CHECK);
 320   if (result.get_jint() != JNI_OK) {
 321     vm_exit_during_initialization(); // no message or exception
 322   }
 323 
 324   universe_post_module_init();
 325 }
 326 
 327 // Phase 3. final setup - set security manager, system class loader and TCCL
 328 //
 329 //     This will instantiate and set the security manager, set the system class
 330 //     loader as well as the thread context class loader.  The security manager
 331 //     and system class loader may be a custom class loaded from -Xbootclasspath/a,
 332 //     other modules or the application's classpath.
 333 static void call_initPhase3(TRAPS) {
 334   Klass* klass = vmClasses::System_klass();
 335   JavaValue result(T_VOID);
 336   JavaCalls::call_static(&result, klass, vmSymbols::initPhase3_name(),
 337                                          vmSymbols::void_method_signature(), CHECK);
 338 }
 339 
 340 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
 341   TraceTime timer("Initialize java.lang classes", TRACETIME_LOG(Info, startuptime));
 342 
 343   initialize_class(vmSymbols::java_lang_String(), CHECK);
 344 
 345   // Inject CompactStrings value after the static initializers for String ran.
 346   java_lang_String::set_compact_strings(CompactStrings);
 347 
 348   // Initialize java_lang.System (needed before creating the thread)
 349   initialize_class(vmSymbols::java_lang_System(), CHECK);
 350   // The VM creates & returns objects of this class. Make sure it's initialized.
 351   initialize_class(vmSymbols::java_lang_Class(), CHECK);
 352   initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
 353   Handle thread_group = create_initial_thread_group(CHECK);
 354   Universe::set_main_thread_group(thread_group());
 355   initialize_class(vmSymbols::java_lang_Thread(), CHECK);
 356   create_initial_thread(thread_group, main_thread, CHECK);
 357 
 358   // The VM creates objects of this class.
 359   initialize_class(vmSymbols::java_lang_Module(), CHECK);
 360 
 361 #ifdef ASSERT
 362   InstanceKlass *k = vmClasses::UnsafeConstants_klass();
 363   assert(k->is_not_initialized(), "UnsafeConstants should not already be initialized");
 364 #endif
 365 
 366   // initialize the hardware-specific constants needed by Unsafe
 367   initialize_class(vmSymbols::jdk_internal_misc_UnsafeConstants(), CHECK);
 368   jdk_internal_misc_UnsafeConstants::set_unsafe_constants();
 369 
 370   // The VM preresolves methods to these classes. Make sure that they get initialized
 371   initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
 372   initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
 373 
 374   // Phase 1 of the system initialization in the library, java.lang.System class initialization
 375   call_initPhase1(CHECK);
 376 
 377   // Get the Java runtime name, version, and vendor info after java.lang.System is initialized.
 378   // Some values are actually configure-time constants but some can be set via the jlink tool and
 379   // so must be read dynamically. We treat them all the same.
 380   InstanceKlass* ik = SystemDictionary::find_instance_klass(THREAD, vmSymbols::java_lang_VersionProps(),
 381                                                             Handle(), Handle());
 382   {
 383     ResourceMark rm(main_thread);
 384     JDK_Version::set_java_version(get_java_version_info(ik, vmSymbols::java_version_name()));
 385 
 386     JDK_Version::set_runtime_name(get_java_version_info(ik, vmSymbols::java_runtime_name_name()));
 387 
 388     JDK_Version::set_runtime_version(get_java_version_info(ik, vmSymbols::java_runtime_version_name()));
 389 
 390     JDK_Version::set_runtime_vendor_version(get_java_version_info(ik, vmSymbols::java_runtime_vendor_version_name()));
 391 
 392     JDK_Version::set_runtime_vendor_vm_bug_url(get_java_version_info(ik, vmSymbols::java_runtime_vendor_vm_bug_url_name()));
 393   }
 394 
 395   // an instance of OutOfMemory exception has been allocated earlier
 396   initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
 397   initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
 398   initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
 399   initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
 400   initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
 401   initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
 402   initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
 403   initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
 404 }
 405 
 406 void Threads::initialize_jsr292_core_classes(TRAPS) {
 407   TraceTime timer("Initialize java.lang.invoke classes", TRACETIME_LOG(Info, startuptime));
 408 
 409   initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
 410   initialize_class(vmSymbols::java_lang_invoke_ResolvedMethodName(), CHECK);
 411   initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
 412   initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
 413 }
 414 
 415 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
 416   extern void JDK_Version_init();
 417 
 418   // Preinitialize version info.
 419   VM_Version::early_initialize();
 420 
 421   // Check version
 422   if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
 423 
 424   // Initialize library-based TLS
 425   ThreadLocalStorage::init();
 426 
 427   // Initialize the output stream module
 428   ostream_init();
 429 
 430   // Process java launcher properties.
 431   Arguments::process_sun_java_launcher_properties(args);
 432 
 433   // Initialize the os module
 434   os::init();
 435 
 436   MACOS_AARCH64_ONLY(os::current_thread_enable_wx(WXWrite));
 437 
 438   // Record VM creation timing statistics
 439   TraceVmCreationTime create_vm_timer;
 440   create_vm_timer.start();
 441 
 442   // Initialize system properties.
 443   Arguments::init_system_properties();
 444 
 445   // So that JDK version can be used as a discriminator when parsing arguments
 446   JDK_Version_init();
 447 
 448   // Update/Initialize System properties after JDK version number is known
 449   Arguments::init_version_specific_system_properties();
 450 
 451   // Make sure to initialize log configuration *before* parsing arguments
 452   LogConfiguration::initialize(create_vm_timer.begin_time());
 453 
 454   // Parse arguments
 455   // Note: this internally calls os::init_container_support()
 456   jint parse_result = Arguments::parse(args);
 457   if (parse_result != JNI_OK) return parse_result;
 458 
 459   // Initialize NMT right after argument parsing to keep the pre-NMT-init window small.
 460   MemTracker::initialize();
 461 
 462   os::init_before_ergo();
 463 
 464   jint ergo_result = Arguments::apply_ergo();
 465   if (ergo_result != JNI_OK) return ergo_result;
 466 
 467   // Final check of all ranges after ergonomics which may change values.
 468   if (!JVMFlagLimit::check_all_ranges()) {
 469     return JNI_EINVAL;
 470   }
 471 
 472   // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
 473   bool constraint_result = JVMFlagLimit::check_all_constraints(JVMFlagConstraintPhase::AfterErgo);
 474   if (!constraint_result) {
 475     return JNI_EINVAL;
 476   }
 477 
 478   if (PauseAtStartup) {
 479     os::pause();
 480   }
 481 
 482   HOTSPOT_VM_INIT_BEGIN();
 483 
 484   // Timing (must come after argument parsing)
 485   TraceTime timer("Create VM", TRACETIME_LOG(Info, startuptime));
 486 
 487   // Initialize the os module after parsing the args
 488   jint os_init_2_result = os::init_2();
 489   if (os_init_2_result != JNI_OK) return os_init_2_result;
 490 
 491 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT
 492   // Initialize assert poison page mechanism.
 493   if (ShowRegistersOnAssert) {
 494     initialize_assert_poison();
 495   }
 496 #endif // CAN_SHOW_REGISTERS_ON_ASSERT
 497 
 498   SafepointMechanism::initialize();
 499 
 500   jint adjust_after_os_result = Arguments::adjust_after_os();
 501   if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
 502 
 503   // Initialize output stream logging
 504   ostream_init_log();
 505 
 506   // Should happen before any agent attaches and pokes into vmStructs
 507 #if INCLUDE_VM_STRUCTS
 508   if (UseCompactObjectHeaders) {
 509     VMStructs::compact_headers_overrides();
 510   }
 511 #endif
 512 
 513   // Launch -agentlib/-agentpath and converted -Xrun agents
 514   JvmtiAgentList::load_agents();
 515 
 516   // Initialize Threads state
 517   _number_of_threads = 0;
 518   _number_of_non_daemon_threads = 0;
 519 
 520   // Initialize global data structures and create system classes in heap
 521   vm_init_globals();
 522 
 523 #if INCLUDE_JVMCI
 524   if (JVMCICounterSize > 0) {
 525     JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtJVMCI);
 526     memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize);
 527   } else {
 528     JavaThread::_jvmci_old_thread_counters = nullptr;
 529   }
 530 #endif // INCLUDE_JVMCI
 531 
 532   // Initialize OopStorage for threadObj
 533   JavaThread::_thread_oop_storage = OopStorageSet::create_strong("Thread OopStorage", mtThread);
 534 
 535   // Attach the main thread to this os thread
 536   JavaThread* main_thread = new JavaThread();
 537   main_thread->set_thread_state(_thread_in_vm);
 538   main_thread->initialize_thread_current();
 539   // must do this before set_active_handles
 540   main_thread->record_stack_base_and_size();
 541   main_thread->register_thread_stack_with_NMT();
 542   main_thread->set_active_handles(JNIHandleBlock::allocate_block());
 543   MACOS_AARCH64_ONLY(main_thread->init_wx());
 544 
 545   if (!main_thread->set_as_starting_thread()) {
 546     vm_shutdown_during_initialization(
 547                                       "Failed necessary internal allocation. Out of swap space");
 548     main_thread->smr_delete();
 549     *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
 550     return JNI_ENOMEM;
 551   }
 552 
 553   // Enable guard page *after* os::create_main_thread(), otherwise it would
 554   // crash Linux VM, see notes in os_linux.cpp.
 555   main_thread->stack_overflow_state()->create_stack_guard_pages();
 556 
 557   // Initialize Java-Level synchronization subsystem
 558   ObjectMonitor::Initialize();
 559   ObjectSynchronizer::initialize();
 560 
 561   // Initialize global modules
 562   jint status = init_globals();
 563   if (status != JNI_OK) {
 564     main_thread->smr_delete();
 565     *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
 566     return status;
 567   }
 568 
 569   // Create WatcherThread as soon as we can since we need it in case
 570   // of hangs during error reporting.
 571   WatcherThread::start();
 572 
 573   // Add main_thread to threads list to finish barrier setup with
 574   // on_thread_attach.  Should be before starting to build Java objects in
 575   // init_globals2, which invokes barriers.
 576   {
 577     MutexLocker mu(Threads_lock);
 578     Threads::add(main_thread);
 579   }
 580 
 581   status = init_globals2();
 582   if (status != JNI_OK) {
 583     Threads::remove(main_thread, false);
 584     // It is possible that we managed to fully initialize Universe but have then
 585     // failed by throwing an exception. In that case our caller JNI_CreateJavaVM
 586     // will want to report it, so we can't delete the main thread.
 587     if (!main_thread->has_pending_exception()) {
 588       main_thread->smr_delete();
 589     }
 590     *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
 591     return status;
 592   }
 593 
 594   JFR_ONLY(Jfr::on_create_vm_1();)
 595 
 596   // Should be done after the heap is fully created
 597   main_thread->cache_global_variables();
 598 
 599   // Any JVMTI raw monitors entered in onload will transition into
 600   // real raw monitor. VM is setup enough here for raw monitor enter.
 601   JvmtiExport::transition_pending_onload_raw_monitors();
 602 
 603   // Create the VMThread
 604   { TraceTime timer("Start VMThread", TRACETIME_LOG(Info, startuptime));
 605 
 606     VMThread::create();
 607     VMThread* vmthread = VMThread::vm_thread();
 608 
 609     if (!os::create_thread(vmthread, os::vm_thread)) {
 610       vm_exit_during_initialization("Cannot create VM thread. "
 611                                     "Out of system resources.");
 612     }
 613 
 614     // Wait for the VM thread to become ready, and VMThread::run to initialize
 615     // Monitors can have spurious returns, must always check another state flag
 616     {
 617       MonitorLocker ml(Notify_lock);
 618       os::start_thread(vmthread);
 619       while (!vmthread->is_running()) {
 620         ml.wait();
 621       }
 622     }
 623   }
 624 
 625   assert(Universe::is_fully_initialized(), "not initialized");
 626   if (VerifyDuringStartup) {
 627     // Make sure we're starting with a clean slate.
 628     VM_Verify verify_op;
 629     VMThread::execute(&verify_op);
 630   }
 631 
 632   // We need this to update the java.vm.info property in case any flags used
 633   // to initially define it have been changed. This is needed for both CDS
 634   // since UseSharedSpaces may be changed after java.vm.info
 635   // is initially computed. See Abstract_VM_Version::vm_info_string().
 636   // This update must happen before we initialize the java classes, but
 637   // after any initialization logic that might modify the flags.
 638   Arguments::update_vm_info_property(VM_Version::vm_info_string());
 639 
 640   JavaThread* THREAD = JavaThread::current(); // For exception macros.
 641   HandleMark hm(THREAD);
 642 
 643   // Always call even when there are not JVMTI environments yet, since environments
 644   // may be attached late and JVMTI must track phases of VM execution
 645   JvmtiExport::enter_early_start_phase();
 646 
 647   // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
 648   JvmtiExport::post_early_vm_start();
 649 
 650   // Launch -Xrun agents early if EagerXrunInit is set
 651   if (EagerXrunInit) {
 652     JvmtiAgentList::load_xrun_agents();
 653   }
 654 
 655   initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
 656 
 657   quicken_jni_functions();
 658 
 659   // No more stub generation allowed after that point.
 660   StubCodeDesc::freeze();
 661 
 662   // Set flag that basic initialization has completed. Used by exceptions and various
 663   // debug stuff, that does not work until all basic classes have been initialized.
 664   set_init_completed();
 665 
 666   LogConfiguration::post_initialize();
 667   Metaspace::post_initialize();
 668   MutexLockerImpl::post_initialize();
 669 
 670   HOTSPOT_VM_INIT_END();
 671 
 672   // record VM initialization completion time
 673 #if INCLUDE_MANAGEMENT
 674   Management::record_vm_init_completed();
 675 #endif // INCLUDE_MANAGEMENT
 676 
 677   log_info(os)("Initialized VM with process ID %d", os::current_process_id());
 678 
 679   // Signal Dispatcher needs to be started before VMInit event is posted
 680   os::initialize_jdk_signal_support(CHECK_JNI_ERR);
 681 
 682   // Start Attach Listener if +StartAttachListener or it can't be started lazily
 683   if (!DisableAttachMechanism) {
 684     AttachListener::vm_start();
 685     if (StartAttachListener || AttachListener::init_at_startup()) {
 686       AttachListener::init();
 687     }
 688   }
 689 
 690   // Launch -Xrun agents if EagerXrunInit is not set.
 691   if (!EagerXrunInit) {
 692     JvmtiAgentList::load_xrun_agents();
 693   }
 694 
 695   Arena::start_chunk_pool_cleaner_task();
 696 
 697   // Start the service thread
 698   // The service thread enqueues JVMTI deferred events and does various hashtable
 699   // and other cleanups.  Needs to start before the compilers start posting events.
 700   ServiceThread::initialize();
 701 
 702   // Start the monitor deflation thread:
 703   MonitorDeflationThread::initialize();
 704 
 705   // initialize compiler(s)
 706 #if defined(COMPILER1) || COMPILER2_OR_JVMCI
 707   bool init_compilation = true;
 708 #if INCLUDE_JVMCI
 709   bool force_JVMCI_initialization = false;
 710   if (EnableJVMCI) {
 711     // Initialize JVMCI eagerly when it is explicitly requested.
 712     // Or when JVMCILibDumpJNIConfig or JVMCIPrintProperties is enabled.
 713     force_JVMCI_initialization = EagerJVMCI || JVMCIPrintProperties || JVMCILibDumpJNIConfig;
 714     if (!force_JVMCI_initialization && UseJVMCICompiler && !UseJVMCINativeLibrary && (!UseInterpreter || !BackgroundCompilation)) {
 715       // Force initialization of jarjvmci otherwise requests for blocking
 716       // compilations will not actually block until jarjvmci is initialized.
 717       force_JVMCI_initialization = true;
 718     }
 719     if (JVMCIPrintProperties || JVMCILibDumpJNIConfig) {
 720       // Both JVMCILibDumpJNIConfig and JVMCIPrintProperties exit the VM
 721       // so compilation should be disabled. This prevents dumping or
 722       // printing from happening more than once.
 723       init_compilation = false;
 724     }
 725   }
 726 #endif
 727   if (init_compilation) {
 728     CompileBroker::compilation_init(CHECK_JNI_ERR);
 729   }
 730 #endif
 731 
 732   // Start string deduplication thread if requested.
 733   if (StringDedup::is_enabled()) {
 734     StringDedup::start();
 735   }
 736 
 737   // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
 738   // It is done after compilers are initialized, because otherwise compilations of
 739   // signature polymorphic MH intrinsics can be missed
 740   // (see SystemDictionary::find_method_handle_intrinsic).
 741   initialize_jsr292_core_classes(CHECK_JNI_ERR);
 742 
 743   // This will initialize the module system.  Only java.base classes can be
 744   // loaded until phase 2 completes
 745   call_initPhase2(CHECK_JNI_ERR);
 746 
 747   JFR_ONLY(Jfr::on_create_vm_2();)
 748 
 749   // Always call even when there are not JVMTI environments yet, since environments
 750   // may be attached late and JVMTI must track phases of VM execution
 751   JvmtiExport::enter_start_phase();
 752 
 753   // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
 754   JvmtiExport::post_vm_start();
 755 
 756   // Final system initialization including security manager and system class loader
 757   call_initPhase3(CHECK_JNI_ERR);
 758 
 759   // cache the system and platform class loaders
 760   SystemDictionary::compute_java_loaders(CHECK_JNI_ERR);
 761 
 762   if (Continuations::enabled()) {
 763     // Initialize Continuation class now so that failure to create enterSpecial/doYield
 764     // special nmethods due to limited CodeCache size can be treated as a fatal error at
 765     // startup with the proper message that CodeCache size is too small.
 766     initialize_class(vmSymbols::jdk_internal_vm_Continuation(), CHECK_JNI_ERR);
 767   }
 768 
 769 #if INCLUDE_CDS
 770   // capture the module path info from the ModuleEntryTable
 771   ClassLoader::initialize_module_path(THREAD);
 772   if (HAS_PENDING_EXCEPTION) {
 773     java_lang_Throwable::print(PENDING_EXCEPTION, tty);
 774     vm_exit_during_initialization("ClassLoader::initialize_module_path() failed unexpectedly");
 775   }
 776 #endif
 777 
 778 #if INCLUDE_JVMCI
 779   if (force_JVMCI_initialization) {
 780     JVMCI::initialize_compiler(CHECK_JNI_ERR);
 781   }
 782 #endif
 783 
 784   if (NativeHeapTrimmer::enabled()) {
 785     NativeHeapTrimmer::initialize();
 786   }
 787 
 788   // Always call even when there are not JVMTI environments yet, since environments
 789   // may be attached late and JVMTI must track phases of VM execution
 790   JvmtiExport::enter_live_phase();
 791 
 792   // Make perfmemory accessible
 793   PerfMemory::set_accessible(true);
 794 
 795   // Notify JVMTI agents that VM initialization is complete - nop if no agents.
 796   JvmtiExport::post_vm_initialized();
 797 
 798   JFR_ONLY(Jfr::on_create_vm_3();)
 799 
 800 #if INCLUDE_MANAGEMENT
 801   Management::initialize(THREAD);
 802 
 803   if (HAS_PENDING_EXCEPTION) {
 804     // management agent fails to start possibly due to
 805     // configuration problem and is responsible for printing
 806     // stack trace if appropriate. Simply exit VM.
 807     vm_exit(1);
 808   }
 809 #endif // INCLUDE_MANAGEMENT
 810 
 811   StatSampler::engage();
 812   if (CheckJNICalls)                  JniPeriodicChecker::engage();
 813 
 814 #if INCLUDE_RTM_OPT
 815   RTMLockingCounters::init();
 816 #endif
 817 
 818   call_postVMInitHook(THREAD);
 819   // The Java side of PostVMInitHook.run must deal with all
 820   // exceptions and provide means of diagnosis.
 821   if (HAS_PENDING_EXCEPTION) {
 822     CLEAR_PENDING_EXCEPTION;
 823   }
 824 
 825   // Let WatcherThread run all registered periodic tasks now.
 826   // NOTE:  All PeriodicTasks should be registered by now. If they
 827   //   aren't, late joiners might appear to start slowly (we might
 828   //   take a while to process their first tick).
 829   WatcherThread::run_all_tasks();
 830 
 831   create_vm_timer.end();
 832 #ifdef ASSERT
 833   _vm_complete = true;
 834 #endif
 835 
 836   if (CDSConfig::is_dumping_static_archive()) {
 837     MetaspaceShared::preload_and_dump();
 838   }
 839 
 840   return JNI_OK;
 841 }
 842 
 843 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
 844 // the program falls off the end of main(). Another VM exit path is through
 845 // vm_exit() when the program calls System.exit() to return a value or when
 846 // there is a serious error in VM. The two shutdown paths are not exactly
 847 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
 848 // and VM_Exit op at VM level.
 849 //
 850 // Shutdown sequence:
 851 //   + Shutdown native memory tracking if it is on
 852 //   + Wait until we are the last non-daemon thread to execute
 853 //     <-- every thing is still working at this moment -->
 854 //   + Call java.lang.Shutdown.shutdown(), which will invoke Java level
 855 //        shutdown hooks
 856 //   + Call before_exit(), prepare for VM exit
 857 //      > run VM level shutdown hooks (they are registered through JVM_OnExit(),
 858 //        currently the only user of this mechanism is File.deleteOnExit())
 859 //      > stop StatSampler, watcher thread,
 860 //        post thread end and vm death events to JVMTI,
 861 //        stop signal thread
 862 //   + Call JavaThread::exit(), it will:
 863 //      > release JNI handle blocks, remove stack guard pages
 864 //      > remove this thread from Threads list
 865 //     <-- no more Java code from this thread after this point -->
 866 //   + Stop VM thread, it will bring the remaining VM to a safepoint and stop
 867 //     the compiler threads at safepoint
 868 //     <-- do not use anything that could get blocked by Safepoint -->
 869 //   + Disable tracing at JNI/JVM barriers
 870 //   + Set _vm_exited flag for threads that are still running native code
 871 //   + Call exit_globals()
 872 //      > deletes tty
 873 //      > deletes PerfMemory resources
 874 //   + Delete this thread
 875 //   + Return to caller
 876 
 877 void Threads::destroy_vm() {
 878   JavaThread* thread = JavaThread::current();
 879 
 880 #ifdef ASSERT
 881   _vm_complete = false;
 882 #endif
 883   // Wait until we are the last non-daemon thread to execute, or
 884   // if we are a daemon then wait until the last non-daemon thread has
 885   // executed.
 886   bool daemon = java_lang_Thread::is_daemon(thread->threadObj());
 887   int expected = daemon ? 0 : 1;
 888   {
 889     MonitorLocker nu(Threads_lock);
 890     while (Threads::number_of_non_daemon_threads() > expected)
 891       // This wait should make safepoint checks, wait without a timeout.
 892       nu.wait(0);
 893   }
 894 
 895   EventShutdown e;
 896   if (e.should_commit()) {
 897     e.set_reason("No remaining non-daemon Java threads");
 898     e.commit();
 899   }
 900 
 901   // Hang forever on exit if we are reporting an error.
 902   if (ShowMessageBoxOnError && VMError::is_error_reported()) {
 903     os::infinite_sleep();
 904   }
 905   os::wait_for_keypress_at_exit();
 906 
 907   // run Java level shutdown hooks
 908   thread->invoke_shutdown_hooks();
 909 
 910   before_exit(thread);
 911 
 912   thread->exit(true);
 913 
 914   // We are no longer on the main thread list but could still be in a
 915   // secondary list where another thread may try to interact with us.
 916   // So wait until all such interactions are complete before we bring
 917   // the VM to the termination safepoint. Normally this would be done
 918   // using thread->smr_delete() below where we delete the thread, but
 919   // we can't call that after the termination safepoint is active as
 920   // we will deadlock on the Threads_lock. Once all interactions are
 921   // complete it is safe to directly delete the thread at any time.
 922   ThreadsSMRSupport::wait_until_not_protected(thread);
 923 
 924   // Stop VM thread.
 925   {
 926     // 4945125 The vm thread comes to a safepoint during exit.
 927     // GC vm_operations can get caught at the safepoint, and the
 928     // heap is unparseable if they are caught. Grab the Heap_lock
 929     // to prevent this. The GC vm_operations will not be able to
 930     // queue until after the vm thread is dead. After this point,
 931     // we'll never emerge out of the safepoint before the VM exits.
 932     // Assert that the thread is terminated so that acquiring the
 933     // Heap_lock doesn't cause the terminated thread to participate in
 934     // the safepoint protocol.
 935 
 936     assert(thread->is_terminated(), "must be terminated here");
 937     MutexLocker ml(Heap_lock);
 938 
 939     VMThread::wait_for_vm_thread_exit();
 940     assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
 941     VMThread::destroy();
 942   }
 943 
 944   // Now, all Java threads are gone except daemon threads. Daemon threads
 945   // running Java code or in VM are stopped by the Safepoint. However,
 946   // daemon threads executing native code are still running.  But they
 947   // will be stopped at native=>Java/VM barriers. Note that we can't
 948   // simply kill or suspend them, as it is inherently deadlock-prone.
 949 
 950   VM_Exit::set_vm_exited();
 951 
 952   // Clean up ideal graph printers after the VMThread has started
 953   // the final safepoint which will block all the Compiler threads.
 954   // Note that this Thread has already logically exited so the
 955   // clean_up() function's use of a JavaThreadIteratorWithHandle
 956   // would be a problem except set_vm_exited() has remembered the
 957   // shutdown thread which is granted a policy exception.
 958 #if defined(COMPILER2) && !defined(PRODUCT)
 959   IdealGraphPrinter::clean_up();
 960 #endif
 961 
 962   notify_vm_shutdown();
 963 
 964   // exit_globals() will delete tty
 965   exit_globals();
 966 
 967   // Deleting the shutdown thread here is safe. See comment on
 968   // wait_until_not_protected() above.
 969   delete thread;
 970 
 971 #if INCLUDE_JVMCI
 972   if (JVMCICounterSize > 0) {
 973     FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters);
 974   }
 975 #endif
 976 
 977   LogConfiguration::finalize();
 978 }
 979 
 980 
 981 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
 982   if (version == JNI_VERSION_1_1) return JNI_TRUE;
 983   return is_supported_jni_version(version);
 984 }
 985 
 986 
 987 jboolean Threads::is_supported_jni_version(jint version) {
 988   if (version == JNI_VERSION_1_2) return JNI_TRUE;
 989   if (version == JNI_VERSION_1_4) return JNI_TRUE;
 990   if (version == JNI_VERSION_1_6) return JNI_TRUE;
 991   if (version == JNI_VERSION_1_8) return JNI_TRUE;
 992   if (version == JNI_VERSION_9) return JNI_TRUE;
 993   if (version == JNI_VERSION_10) return JNI_TRUE;
 994   if (version == JNI_VERSION_19) return JNI_TRUE;
 995   if (version == JNI_VERSION_20) return JNI_TRUE;
 996   if (version == JNI_VERSION_21) return JNI_TRUE;
 997   return JNI_FALSE;
 998 }
 999 
1000 void Threads::add(JavaThread* p, bool force_daemon) {
1001   // The threads lock must be owned at this point
1002   assert(Threads_lock->owned_by_self(), "must have threads lock");
1003 
1004   BarrierSet::barrier_set()->on_thread_attach(p);
1005 
1006   // Once a JavaThread is added to the Threads list, smr_delete() has
1007   // to be used to delete it. Otherwise we can just delete it directly.
1008   p->set_on_thread_list();
1009 
1010   _number_of_threads++;
1011   oop threadObj = p->threadObj();
1012   bool daemon = true;
1013   // Bootstrapping problem: threadObj can be null for initial
1014   // JavaThread (or for threads attached via JNI)
1015   if (!force_daemon &&
1016       (threadObj == nullptr || !java_lang_Thread::is_daemon(threadObj))) {
1017     _number_of_non_daemon_threads++;
1018     daemon = false;
1019   }
1020 
1021   ThreadService::add_thread(p, daemon);
1022 
1023   // Maintain fast thread list
1024   ThreadsSMRSupport::add_thread(p);
1025 
1026   // Increase the ObjectMonitor ceiling for the new thread.
1027   ObjectSynchronizer::inc_in_use_list_ceiling();
1028 
1029   // Possible GC point.
1030   Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p));
1031 
1032   // Make new thread known to active EscapeBarrier
1033   EscapeBarrier::thread_added(p);
1034 }
1035 
1036 void Threads::remove(JavaThread* p, bool is_daemon) {
1037   // Extra scope needed for Thread_lock, so we can check
1038   // that we do not remove thread without safepoint code notice
1039   { MonitorLocker ml(Threads_lock);
1040 
1041     if (ThreadIdTable::is_initialized()) {
1042       // This cleanup must be done before the current thread's GC barrier
1043       // is detached since we need to touch the threadObj oop.
1044       jlong tid = SharedRuntime::get_java_tid(p);
1045       ThreadIdTable::remove_thread(tid);
1046     }
1047 
1048     // BarrierSet state must be destroyed after the last thread transition
1049     // before the thread terminates. Thread transitions result in calls to
1050     // StackWatermarkSet::on_safepoint(), which performs GC processing,
1051     // requiring the GC state to be alive.
1052     BarrierSet::barrier_set()->on_thread_detach(p);
1053     if (p->is_exiting()) {
1054       // If we got here via JavaThread::exit(), then we remember that the
1055       // thread's GC barrier has been detached. We don't do this when we get
1056       // here from another path, e.g., cleanup_failed_attach_current_thread().
1057       p->set_terminated(JavaThread::_thread_gc_barrier_detached);
1058     }
1059 
1060     assert(ThreadsSMRSupport::get_java_thread_list()->includes(p), "p must be present");
1061 
1062     // Maintain fast thread list
1063     ThreadsSMRSupport::remove_thread(p);
1064 
1065     _number_of_threads--;
1066     if (!is_daemon) {
1067       _number_of_non_daemon_threads--;
1068 
1069       // If this is the last non-daemon thread then we need to do
1070       // a notify on the Threads_lock so a thread waiting
1071       // on destroy_vm will wake up. But that thread could be a daemon
1072       // or non-daemon, so we notify for both the 0 and 1 case.
1073       if (number_of_non_daemon_threads() <= 1) {
1074         ml.notify_all();
1075       }
1076     }
1077     ThreadService::remove_thread(p, is_daemon);
1078 
1079     // Make sure that safepoint code disregard this thread. This is needed since
1080     // the thread might mess around with locks after this point. This can cause it
1081     // to do callbacks into the safepoint code. However, the safepoint code is not aware
1082     // of this thread since it is removed from the queue.
1083     p->set_terminated(JavaThread::_thread_terminated);
1084 
1085     // Notify threads waiting in EscapeBarriers
1086     EscapeBarrier::thread_removed(p);
1087   } // unlock Threads_lock
1088 
1089   // Reduce the ObjectMonitor ceiling for the exiting thread.
1090   ObjectSynchronizer::dec_in_use_list_ceiling();
1091 
1092   // Since Events::log uses a lock, we grab it outside the Threads_lock
1093   Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p));
1094 }
1095 
1096 // Operations on the Threads list for GC.  These are not explicitly locked,
1097 // but the garbage collector must provide a safe context for them to run.
1098 // In particular, these things should never be called when the Threads_lock
1099 // is held by some other thread. (Note: the Safepoint abstraction also
1100 // uses the Threads_lock to guarantee this property. It also makes sure that
1101 // all threads gets blocked when exiting or starting).
1102 
1103 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) {
1104   ALL_JAVA_THREADS(p) {
1105     p->oops_do(f, cf);
1106   }
1107   VMThread::vm_thread()->oops_do(f, cf);
1108 }
1109 
1110 void Threads::change_thread_claim_token() {
1111   if (++_thread_claim_token == 0) {
1112     // On overflow of the token counter, there is a risk of future
1113     // collisions between a new global token value and a stale token
1114     // for a thread, because not all iterations visit all threads.
1115     // (Though it's pretty much a theoretical concern for non-trivial
1116     // token counter sizes.)  To deal with the possibility, reset all
1117     // the thread tokens to zero on global token overflow.
1118     struct ResetClaims : public ThreadClosure {
1119       virtual void do_thread(Thread* t) {
1120         t->claim_threads_do(false, 0);
1121       }
1122     } reset_claims;
1123     Threads::threads_do(&reset_claims);
1124     // On overflow, update the global token to non-zero, to
1125     // avoid the special "never claimed" initial thread value.
1126     _thread_claim_token = 1;
1127   }
1128 }
1129 
1130 #ifdef ASSERT
1131 static void assert_thread_claimed(const char* kind, Thread* t, uintx expected) {
1132   const uintx token = t->threads_do_token();
1133   assert(token == expected,
1134          "%s " PTR_FORMAT " has incorrect value " UINTX_FORMAT " != "
1135          UINTX_FORMAT, kind, p2i(t), token, expected);
1136 }
1137 
1138 void Threads::assert_all_threads_claimed() {
1139   ALL_JAVA_THREADS(p) {
1140     assert_thread_claimed("JavaThread", p, _thread_claim_token);
1141   }
1142 
1143   struct NJTClaimedVerifierClosure : public ThreadClosure {
1144     uintx _thread_claim_token;
1145 
1146     NJTClaimedVerifierClosure(uintx thread_claim_token) : ThreadClosure(), _thread_claim_token(thread_claim_token) { }
1147 
1148     virtual void do_thread(Thread* thread) override {
1149       assert_thread_claimed("Non-JavaThread", VMThread::vm_thread(), _thread_claim_token);
1150     }
1151   } tc(_thread_claim_token);
1152 
1153   non_java_threads_do(&tc);
1154 }
1155 #endif // ASSERT
1156 
1157 class ParallelOopsDoThreadClosure : public ThreadClosure {
1158 private:
1159   OopClosure* _f;
1160   CodeBlobClosure* _cf;
1161 public:
1162   ParallelOopsDoThreadClosure(OopClosure* f, CodeBlobClosure* cf) : _f(f), _cf(cf) {}
1163   void do_thread(Thread* t) {
1164     t->oops_do(_f, _cf);
1165   }
1166 };
1167 
1168 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf) {
1169   ParallelOopsDoThreadClosure tc(f, cf);
1170   possibly_parallel_threads_do(is_par, &tc);
1171 }
1172 
1173 void Threads::metadata_do(MetadataClosure* f) {
1174   ALL_JAVA_THREADS(p) {
1175     p->metadata_do(f);
1176   }
1177 }
1178 
1179 class ThreadHandlesClosure : public ThreadClosure {
1180   void (*_f)(Metadata*);
1181  public:
1182   ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
1183   virtual void do_thread(Thread* thread) {
1184     thread->metadata_handles_do(_f);
1185   }
1186 };
1187 
1188 void Threads::metadata_handles_do(void f(Metadata*)) {
1189   // Only walk the Handles in Thread.
1190   ThreadHandlesClosure handles_closure(f);
1191   threads_do(&handles_closure);
1192 }
1193 
1194 // Get count Java threads that are waiting to enter the specified monitor.
1195 GrowableArray<JavaThread*>* Threads::get_pending_threads(ThreadsList * t_list,
1196                                                          int count,
1197                                                          address monitor) {
1198   GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
1199 
1200   int i = 0;
1201   for (JavaThread* p : *t_list) {
1202     if (!p->can_call_java()) continue;
1203 
1204     // The first stage of async deflation does not affect any field
1205     // used by this comparison so the ObjectMonitor* is usable here.
1206     address pending = (address)p->current_pending_monitor();
1207     if (pending == monitor) {             // found a match
1208       if (i < count) result->append(p);   // save the first count matches
1209       i++;
1210     }
1211   }
1212 
1213   return result;
1214 }
1215 
1216 
1217 JavaThread *Threads::owning_thread_from_monitor_owner(ThreadsList * t_list,
1218                                                       address owner) {
1219   assert(LockingMode != LM_LIGHTWEIGHT, "Not with new lightweight locking");
1220   // null owner means not locked so we can skip the search
1221   if (owner == nullptr) return nullptr;
1222 
1223   for (JavaThread* p : *t_list) {
1224     // first, see if owner is the address of a Java thread
1225     if (owner == (address)p) return p;
1226   }
1227 
1228   // Cannot assert on lack of success here since this function may be
1229   // used by code that is trying to report useful problem information
1230   // like deadlock detection.
1231   if (LockingMode == LM_MONITOR) return nullptr;
1232 
1233   // If we didn't find a matching Java thread and we didn't force use of
1234   // heavyweight monitors, then the owner is the stack address of the
1235   // Lock Word in the owning Java thread's stack.
1236   //
1237   JavaThread* the_owner = nullptr;
1238   for (JavaThread* q : *t_list) {
1239     if (q->is_lock_owned(owner)) {
1240       the_owner = q;
1241       break;
1242     }
1243   }
1244 
1245   // cannot assert on lack of success here; see above comment
1246   return the_owner;
1247 }
1248 
1249 JavaThread* Threads::owning_thread_from_object(ThreadsList * t_list, oop obj) {
1250   assert(LockingMode == LM_LIGHTWEIGHT, "Only with new lightweight locking");
1251   for (JavaThread* q : *t_list) {
1252     // Need to start processing before accessing oops in the thread.
1253     StackWatermark* watermark = StackWatermarkSet::get(q, StackWatermarkKind::gc);
1254     if (watermark != nullptr) {
1255       watermark->start_processing();
1256     }
1257 
1258     if (q->lock_stack().contains(obj)) {
1259       return q;
1260     }
1261   }
1262   return nullptr;
1263 }
1264 
1265 JavaThread* Threads::owning_thread_from_monitor(ThreadsList* t_list, ObjectMonitor* monitor) {
1266   if (LockingMode == LM_LIGHTWEIGHT) {
1267     if (monitor->is_owner_anonymous()) {
1268       return owning_thread_from_object(t_list, monitor->object());
1269     } else {
1270       Thread* owner = reinterpret_cast<Thread*>(monitor->owner());
1271       assert(owner == nullptr || owner->is_Java_thread(), "only JavaThreads own monitors");
1272       return reinterpret_cast<JavaThread*>(owner);
1273     }
1274   } else {
1275     address owner = (address)monitor->owner();
1276     return owning_thread_from_monitor_owner(t_list, owner);
1277   }
1278 }
1279 
1280 class PrintOnClosure : public ThreadClosure {
1281 private:
1282   outputStream* _st;
1283 
1284 public:
1285   PrintOnClosure(outputStream* st) :
1286       _st(st) {}
1287 
1288   virtual void do_thread(Thread* thread) {
1289     if (thread != nullptr) {
1290       thread->print_on(_st);
1291       _st->cr();
1292     }
1293   }
1294 };
1295 
1296 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
1297 void Threads::print_on(outputStream* st, bool print_stacks,
1298                        bool internal_format, bool print_concurrent_locks,
1299                        bool print_extended_info) {
1300   char buf[32];
1301   st->print_raw_cr(os::local_time_string(buf, sizeof(buf)));
1302 
1303   st->print_cr("Full thread dump %s (%s %s):",
1304                VM_Version::vm_name(),
1305                VM_Version::vm_release(),
1306                VM_Version::vm_info_string());
1307   st->cr();
1308 
1309 #if INCLUDE_SERVICES
1310   // Dump concurrent locks
1311   ConcurrentLocksDump concurrent_locks;
1312   if (print_concurrent_locks) {
1313     concurrent_locks.dump_at_safepoint();
1314   }
1315 #endif // INCLUDE_SERVICES
1316 
1317   ThreadsSMRSupport::print_info_on(st);
1318   st->cr();
1319 
1320   ALL_JAVA_THREADS(p) {
1321     ResourceMark rm;
1322     p->print_on(st, print_extended_info);
1323     if (print_stacks) {
1324       if (internal_format) {
1325         p->trace_stack();
1326       } else {
1327         p->print_stack_on(st);
1328       }
1329     }
1330     st->cr();
1331 #if INCLUDE_SERVICES
1332     if (print_concurrent_locks) {
1333       concurrent_locks.print_locks_on(p, st);
1334     }
1335 #endif // INCLUDE_SERVICES
1336   }
1337 
1338   PrintOnClosure cl(st);
1339   cl.do_thread(VMThread::vm_thread());
1340   Universe::heap()->gc_threads_do(&cl);
1341   cl.do_thread(WatcherThread::watcher_thread());
1342   cl.do_thread(AsyncLogWriter::instance());
1343 
1344   st->flush();
1345 }
1346 
1347 void Threads::print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
1348                              int buflen, bool* found_current) {
1349   if (this_thread != nullptr) {
1350     bool is_current = (current == this_thread);
1351     *found_current = *found_current || is_current;
1352     st->print("%s", is_current ? "=>" : "  ");
1353 
1354     st->print(PTR_FORMAT, p2i(this_thread));
1355     st->print(" ");
1356     this_thread->print_on_error(st, buf, buflen);
1357     st->cr();
1358   }
1359 }
1360 
1361 class PrintOnErrorClosure : public ThreadClosure {
1362   outputStream* _st;
1363   Thread* _current;
1364   char* _buf;
1365   int _buflen;
1366   bool* _found_current;
1367   unsigned _num_printed;
1368  public:
1369   PrintOnErrorClosure(outputStream* st, Thread* current, char* buf,
1370                       int buflen, bool* found_current) :
1371    _st(st), _current(current), _buf(buf), _buflen(buflen), _found_current(found_current),
1372    _num_printed(0) {}
1373 
1374   virtual void do_thread(Thread* thread) {
1375     _num_printed++;
1376     Threads::print_on_error(thread, _st, _current, _buf, _buflen, _found_current);
1377   }
1378 
1379   unsigned num_printed() const { return _num_printed; }
1380 };
1381 
1382 // Threads::print_on_error() is called by fatal error handler. It's possible
1383 // that VM is not at safepoint and/or current thread is inside signal handler.
1384 // Don't print stack trace, as the stack may not be walkable. Don't allocate
1385 // memory (even in resource area), it might deadlock the error handler.
1386 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
1387                              int buflen) {
1388   ThreadsSMRSupport::print_info_on(st);
1389   st->cr();
1390 
1391   bool found_current = false;
1392   st->print_cr("Java Threads: ( => current thread )");
1393   unsigned num_java = 0;
1394   ALL_JAVA_THREADS(thread) {
1395     print_on_error(thread, st, current, buf, buflen, &found_current);
1396     num_java++;
1397   }
1398   st->print_cr("Total: %u", num_java);
1399   st->cr();
1400 
1401   st->print_cr("Other Threads:");
1402   unsigned num_other = ((VMThread::vm_thread() != nullptr) ? 1 : 0) +
1403       ((WatcherThread::watcher_thread() != nullptr) ? 1 : 0) +
1404       ((AsyncLogWriter::instance() != nullptr)  ? 1 : 0);
1405   print_on_error(VMThread::vm_thread(), st, current, buf, buflen, &found_current);
1406   print_on_error(WatcherThread::watcher_thread(), st, current, buf, buflen, &found_current);
1407   print_on_error(AsyncLogWriter::instance(), st, current, buf, buflen, &found_current);
1408 
1409   if (Universe::heap() != nullptr) {
1410     PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current);
1411     Universe::heap()->gc_threads_do(&print_closure);
1412     num_other += print_closure.num_printed();
1413   }
1414 
1415   if (!found_current) {
1416     st->cr();
1417     st->print("=>" PTR_FORMAT " (exited) ", p2i(current));
1418     current->print_on_error(st, buf, buflen);
1419     num_other++;
1420     st->cr();
1421   }
1422   st->print_cr("Total: %u", num_other);
1423   st->cr();
1424 
1425   st->print_cr("Threads with active compile tasks:");
1426   unsigned num = print_threads_compiling(st, buf, buflen);
1427   st->print_cr("Total: %u", num);
1428 }
1429 
1430 unsigned Threads::print_threads_compiling(outputStream* st, char* buf, int buflen, bool short_form) {
1431   unsigned num = 0;
1432   ALL_JAVA_THREADS(thread) {
1433     if (thread->is_Compiler_thread()) {
1434       CompilerThread* ct = (CompilerThread*) thread;
1435 
1436       // Keep task in local variable for null check.
1437       // ct->_task might be set to null by concurring compiler thread
1438       // because it completed the compilation. The task is never freed,
1439       // though, just returned to a free list.
1440       CompileTask* task = ct->task();
1441       if (task != nullptr) {
1442         thread->print_name_on_error(st, buf, buflen);
1443         st->print("  ");
1444         task->print(st, nullptr, short_form, true);
1445         num++;
1446       }
1447     }
1448   }
1449   return num;
1450 }
1451 
1452 void Threads::verify() {
1453   ALL_JAVA_THREADS(p) {
1454     p->verify();
1455   }
1456   VMThread* thread = VMThread::vm_thread();
1457   if (thread != nullptr) thread->verify();
1458 }