1 /*
   2  * Copyright (c) 1997, 2026, 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 "cds/aotLinkedClassBulkLoader.hpp"
  27 #include "cds/aotMetaspace.hpp"
  28 #include "cds/cds_globals.hpp"
  29 #include "cds/cdsConfig.hpp"
  30 #include "cds/heapShared.inline.hpp"
  31 #include "classfile/classLoader.hpp"
  32 #include "classfile/javaClasses.hpp"
  33 #include "classfile/javaThreadStatus.hpp"
  34 #include "classfile/symbolTable.hpp"
  35 #include "classfile/systemDictionary.hpp"
  36 #include "classfile/vmClasses.hpp"
  37 #include "classfile/vmSymbols.hpp"
  38 #include "compiler/compileBroker.hpp"
  39 #include "compiler/compilerThread.hpp"
  40 #include "compiler/compileTask.hpp"
  41 #include "gc/shared/barrierSet.hpp"
  42 #include "gc/shared/barrierSetNMethod.hpp"
  43 #include "gc/shared/gcVMOperations.hpp"
  44 #include "gc/shared/oopStorage.hpp"
  45 #include "gc/shared/oopStorageSet.hpp"
  46 #include "gc/shared/stringdedup/stringDedup.hpp"
  47 #include "jfr/jfrEvents.hpp"
  48 #include "jvm.h"
  49 #include "jvmtifiles/jvmtiEnv.hpp"
  50 #include "logging/log.hpp"
  51 #include "logging/logAsyncWriter.hpp"
  52 #include "logging/logConfiguration.hpp"
  53 #include "memory/allocation.inline.hpp"
  54 #include "memory/iterator.hpp"
  55 #include "memory/oopFactory.hpp"
  56 #include "memory/resourceArea.hpp"
  57 #include "memory/universe.hpp"
  58 #include "nmt/memTracker.hpp"
  59 #include "oops/instanceKlass.hpp"
  60 #include "oops/klass.inline.hpp"
  61 #include "oops/oop.inline.hpp"
  62 #include "oops/symbol.hpp"
  63 #include "prims/jvm_misc.hpp"
  64 #include "prims/jvmtiAgentList.hpp"
  65 #include "prims/jvmtiEnvBase.hpp"
  66 #include "runtime/arguments.hpp"
  67 #include "runtime/fieldDescriptor.inline.hpp"
  68 #include "runtime/flags/jvmFlagLimit.hpp"
  69 #include "runtime/globals.hpp"
  70 #include "runtime/globals_extension.hpp"
  71 #include "runtime/handles.inline.hpp"
  72 #include "runtime/interfaceSupport.inline.hpp"
  73 #include "runtime/java.hpp"
  74 #include "runtime/javaCalls.hpp"
  75 #include "runtime/javaThread.inline.hpp"
  76 #include "runtime/jniHandles.inline.hpp"
  77 #include "runtime/jniPeriodicChecker.hpp"
  78 #include "runtime/lockStack.inline.hpp"
  79 #include "runtime/monitorDeflationThread.hpp"
  80 #include "runtime/mutexLocker.hpp"
  81 #include "runtime/nonJavaThread.hpp"
  82 #include "runtime/objectMonitor.inline.hpp"
  83 #include "runtime/osThread.hpp"
  84 #include "runtime/perfData.hpp"
  85 #include "runtime/safepoint.hpp"
  86 #include "runtime/safepointMechanism.inline.hpp"
  87 #include "runtime/safepointVerifiers.hpp"
  88 #include "runtime/serviceThread.hpp"
  89 #include "runtime/sharedRuntime.hpp"
  90 #include "runtime/stackWatermarkSet.inline.hpp"
  91 #include "runtime/stubCodeGenerator.hpp"
  92 #include "runtime/thread.inline.hpp"
  93 #include "runtime/threads.hpp"
  94 #include "runtime/threadSMR.inline.hpp"
  95 #include "runtime/timer.hpp"
  96 #include "runtime/timerTrace.hpp"
  97 #include "runtime/trimNativeHeap.hpp"
  98 #include "runtime/vm_version.hpp"
  99 #include "runtime/vmOperations.hpp"
 100 #include "sanitizers/address.hpp"
 101 #include "services/attachListener.hpp"
 102 #include "services/management.hpp"
 103 #include "services/threadIdTable.hpp"
 104 #include "services/threadService.hpp"
 105 #include "utilities/debug.hpp"
 106 #include "utilities/dtrace.hpp"
 107 #include "utilities/events.hpp"
 108 #include "utilities/macros.hpp"
 109 #include "utilities/vmError.hpp"
 110 #ifdef COMPILER2
 111 #include "opto/idealGraphPrinter.hpp"
 112 #include "runtime/hotCodeCollector.hpp"
 113 #endif
 114 #if INCLUDE_JFR
 115 #include "jfr/jfr.hpp"
 116 #endif
 117 
 118 // Initialization after module runtime initialization
 119 void universe_post_module_init();  // must happen after call_initPhase2
 120 
 121 
 122 static void initialize_class(Symbol* class_name, TRAPS) {
 123   Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
 124   InstanceKlass::cast(klass)->initialize(CHECK);
 125 }
 126 
 127 
 128 // Creates the initial ThreadGroup
 129 static Handle create_initial_thread_group(TRAPS) {
 130   Handle system_instance = JavaCalls::construct_new_instance(
 131                             vmClasses::ThreadGroup_klass(),
 132                             vmSymbols::void_method_signature(),
 133                             CHECK_NH);
 134   Universe::set_system_thread_group(system_instance());
 135 
 136   Handle string = java_lang_String::create_from_str("main", CHECK_NH);
 137   Handle main_instance = JavaCalls::construct_new_instance(
 138                             vmClasses::ThreadGroup_klass(),
 139                             vmSymbols::threadgroup_string_void_signature(),
 140                             system_instance,
 141                             string,
 142                             CHECK_NH);
 143   return main_instance;
 144 }
 145 
 146 // Creates the initial Thread, and sets it to running.
 147 static void create_initial_thread(Handle thread_group, JavaThread* thread,
 148                                  TRAPS) {
 149   InstanceKlass* ik = vmClasses::Thread_klass();
 150   assert(ik->is_initialized(), "must be");
 151   instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
 152 
 153   // Cannot use JavaCalls::construct_new_instance because the java.lang.Thread
 154   // constructor calls Thread.current(), which must be set here for the
 155   // initial thread.
 156   java_lang_Thread::set_thread(thread_oop(), thread);
 157   thread->set_threadOopHandles(thread_oop());
 158 
 159   Handle string = java_lang_String::create_from_str("main", CHECK);
 160 
 161   JavaValue result(T_VOID);
 162   JavaCalls::call_special(&result, thread_oop,
 163                           ik,
 164                           vmSymbols::object_initializer_name(),
 165                           vmSymbols::threadgroup_string_void_signature(),
 166                           thread_group,
 167                           string,
 168                           CHECK);
 169 
 170   DEBUG_ONLY(int64_t main_thread_tid = java_lang_Thread::thread_id(thread_oop());)
 171   assert(main_thread_tid == ThreadIdentifier::initial(), "");
 172   assert(main_thread_tid == thread->monitor_owner_id(), "");
 173   JFR_ONLY(assert(JFR_JVM_THREAD_ID(thread) == static_cast<traceid>(main_thread_tid), "initial tid mismatch");)
 174 
 175   // Set thread status to running since main thread has
 176   // been started and running.
 177   java_lang_Thread::set_thread_status(thread_oop(),
 178                                       JavaThreadStatus::RUNNABLE);
 179 }
 180 
 181 // Extract version and vendor specific information from
 182 // java.lang.VersionProps fields.
 183 // Returned char* is allocated in the thread's resource area
 184 // so must be copied for permanency.
 185 static const char* get_java_version_info(InstanceKlass* ik,
 186                                          Symbol* field_name) {
 187   fieldDescriptor fd;
 188   bool found = ik != nullptr &&
 189                ik->find_local_field(field_name,
 190                                     vmSymbols::string_signature(), &fd);
 191   if (found) {
 192     oop name_oop = ik->java_mirror()->obj_field(fd.offset());
 193     if (name_oop == nullptr) {
 194       return nullptr;
 195     }
 196     const char* name = java_lang_String::as_utf8_string(name_oop);
 197     return name;
 198   } else {
 199     return nullptr;
 200   }
 201 }
 202 
 203 // ======= Threads ========
 204 
 205 // The Threads class links together all active threads, and provides
 206 // operations over all threads. It is protected by the Threads_lock,
 207 // which is also used in other global contexts like safepointing.
 208 // ThreadsListHandles are used to safely perform operations on one
 209 // or more threads without the risk of the thread exiting during the
 210 // operation.
 211 //
 212 // Note: The Threads_lock is currently more widely used than we
 213 // would like. We are actively migrating Threads_lock uses to other
 214 // mechanisms in order to reduce Threads_lock contention.
 215 
 216 int         Threads::_number_of_threads = 0;
 217 int         Threads::_number_of_non_daemon_threads = 0;
 218 int         Threads::_return_code = 0;
 219 uintx       Threads::_thread_claim_token = 1; // Never zero.
 220 
 221 #ifdef ASSERT
 222 bool        Threads::_vm_complete = false;
 223 #endif
 224 
 225 // General purpose hook into Java code, run once when the VM is initialized.
 226 // The Java library method itself may be changed independently from the VM.
 227 static void call_postVMInitHook(TRAPS) {
 228   Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_vm_PostVMInitHook(), THREAD);
 229   if (klass != nullptr) {
 230     JavaValue result(T_VOID);
 231     JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
 232                            vmSymbols::void_method_signature(),
 233                            CHECK);
 234   }
 235 }
 236 
 237 // All NonJavaThreads (i.e., every non-JavaThread in the system).
 238 void Threads::non_java_threads_do(ThreadClosure* tc) {
 239   NoSafepointVerifier nsv;
 240   for (NonJavaThread::Iterator njti; !njti.end(); njti.step()) {
 241     tc->do_thread(njti.current());
 242   }
 243 }
 244 
 245 // All JavaThreads
 246 #define ALL_JAVA_THREADS(X) \
 247   for (JavaThread* X : *ThreadsSMRSupport::get_java_thread_list())
 248 
 249 // All JavaThreads
 250 void Threads::java_threads_do(ThreadClosure* tc) {
 251   assert_locked_or_safepoint(Threads_lock);
 252   // ALL_JAVA_THREADS iterates through all JavaThreads.
 253   ALL_JAVA_THREADS(p) {
 254     tc->do_thread(p);
 255   }
 256 }
 257 
 258 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system).
 259 void Threads::threads_do(ThreadClosure* tc) {
 260   assert_locked_or_safepoint(Threads_lock);
 261   java_threads_do(tc);
 262   non_java_threads_do(tc);
 263 }
 264 
 265 void Threads::possibly_parallel_threads_do(bool is_par, ThreadClosure* tc) {
 266   assert_at_safepoint();
 267 
 268   uintx claim_token = Threads::thread_claim_token();
 269   ALL_JAVA_THREADS(p) {
 270     if (p->claim_threads_do(is_par, claim_token)) {
 271       tc->do_thread(p);
 272     }
 273   }
 274   for (NonJavaThread::Iterator njti; !njti.end(); njti.step()) {
 275     Thread* current = njti.current();
 276     if (current->claim_threads_do(is_par, claim_token)) {
 277       tc->do_thread(current);
 278     }
 279   }
 280 }
 281 
 282 // The system initialization in the library has three phases.
 283 //
 284 // Phase 1: java.lang.System class initialization
 285 //     java.lang.System is a primordial class loaded and initialized
 286 //     by the VM early during startup.  java.lang.System.<clinit>
 287 //     only does registerNatives and keeps the rest of the class
 288 //     initialization work later until thread initialization completes.
 289 //
 290 //     System.initPhase1 initializes the system properties, the static
 291 //     fields in, out, and err. Set up java signal handlers, OS-specific
 292 //     system settings, and thread group of the main thread.
 293 static void call_initPhase1(TRAPS) {
 294   Klass* klass = vmClasses::System_klass();
 295   JavaValue result(T_VOID);
 296   JavaCalls::call_static(&result, klass, vmSymbols::initPhase1_name(),
 297                                          vmSymbols::void_method_signature(), CHECK);
 298 }
 299 
 300 // Phase 2. Module system initialization
 301 //     This will initialize the module system.  Only java.base classes
 302 //     can be loaded until phase 2 completes.
 303 //
 304 //     Call System.initPhase2 after the compiler initialization and jsr292
 305 //     classes get initialized because module initialization runs a lot of java
 306 //     code, that for performance reasons, should be compiled.  Also, this will
 307 //     enable the startup code to use lambda and other language features in this
 308 //     phase and onward.
 309 //
 310 //     After phase 2, The VM will begin search classes from -Xbootclasspath/a.
 311 static void call_initPhase2(TRAPS) {
 312   TraceTime timer("Initialize module system", TRACETIME_LOG(Info, startuptime));
 313 
 314   Klass* klass = vmClasses::System_klass();
 315 
 316   JavaValue result(T_INT);
 317   JavaCallArguments args;
 318   args.push_int(DisplayVMOutputToStderr);
 319   args.push_int(log_is_enabled(Debug, init)); // print stack trace if exception thrown
 320   JavaCalls::call_static(&result, klass, vmSymbols::initPhase2_name(),
 321                                          vmSymbols::boolean_boolean_int_signature(), &args, CHECK);
 322   if (result.get_jint() != JNI_OK) {
 323     vm_exit_during_initialization(); // no message or exception
 324   }
 325 
 326   universe_post_module_init();
 327 }
 328 
 329 // Phase 3. final setup - set security manager, system class loader and TCCL
 330 //
 331 //     This will instantiate and set the security manager, set the system class
 332 //     loader as well as the thread context class loader.  The security manager
 333 //     and system class loader may be a custom class loaded from -Xbootclasspath/a,
 334 //     other modules or the application's classpath.
 335 static void call_initPhase3(TRAPS) {
 336   Klass* klass = vmClasses::System_klass();
 337   JavaValue result(T_VOID);
 338   JavaCalls::call_static(&result, klass, vmSymbols::initPhase3_name(),
 339                                          vmSymbols::void_method_signature(), CHECK);
 340 }
 341 
 342 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
 343   TraceTime timer("Initialize java.lang classes", TRACETIME_LOG(Info, startuptime));
 344 
 345   // This is before the execution of the very first Java bytecode.
 346   if (CDSConfig::is_using_aot_linked_classes()) {
 347     AOTLinkedClassBulkLoader::link_classes(THREAD);
 348   }
 349 
 350   initialize_class(vmSymbols::java_lang_String(), CHECK);
 351 
 352   // Inject CompactStrings value after the static initializers for String ran.
 353   java_lang_String::set_compact_strings(CompactStrings);
 354 
 355   // Initialize java_lang.System (needed before creating the thread)
 356   initialize_class(vmSymbols::java_lang_System(), CHECK);
 357   // The VM creates & returns objects of this class. Make sure it's initialized.
 358   initialize_class(vmSymbols::java_lang_Class(), CHECK);
 359 
 360   initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
 361   Handle thread_group = create_initial_thread_group(CHECK);
 362   Universe::set_main_thread_group(thread_group());
 363   initialize_class(vmSymbols::java_lang_Thread(), CHECK);
 364   create_initial_thread(thread_group, main_thread, CHECK);
 365 
 366   HeapShared::init_box_classes(CHECK);
 367 
 368   // The VM creates objects of this class.
 369   initialize_class(vmSymbols::java_lang_Module(), CHECK);
 370 
 371 #ifdef ASSERT
 372   InstanceKlass *k = vmClasses::UnsafeConstants_klass();
 373   assert(k->is_not_initialized(), "UnsafeConstants should not already be initialized");
 374 #endif
 375 
 376   // initialize the hardware-specific constants needed by Unsafe
 377   initialize_class(vmSymbols::jdk_internal_misc_UnsafeConstants(), CHECK);
 378   jdk_internal_misc_UnsafeConstants::set_unsafe_constants();
 379 
 380   // The VM preresolves methods to these classes. Make sure that they get initialized
 381   initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
 382   initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
 383 
 384   HeapShared::materialize_thread_object();
 385 
 386   // Phase 1 of the system initialization in the library, java.lang.System class initialization
 387   call_initPhase1(CHECK);
 388 
 389   // Get the Java runtime name, version, and vendor info after java.lang.System is initialized.
 390   // Some values are actually configure-time constants but some can be set via the jlink tool and
 391   // so must be read dynamically. We treat them all the same.
 392   InstanceKlass* ik = SystemDictionary::find_instance_klass(THREAD, vmSymbols::java_lang_VersionProps(),
 393                                                             Handle());
 394   {
 395     ResourceMark rm(main_thread);
 396     JDK_Version::set_java_version(get_java_version_info(ik, vmSymbols::java_version_name()));
 397 
 398     JDK_Version::set_runtime_name(get_java_version_info(ik, vmSymbols::java_runtime_name_name()));
 399 
 400     JDK_Version::set_runtime_version(get_java_version_info(ik, vmSymbols::java_runtime_version_name()));
 401 
 402     JDK_Version::set_runtime_vendor_version(get_java_version_info(ik, vmSymbols::java_runtime_vendor_version_name()));
 403 
 404     JDK_Version::set_runtime_vendor_vm_bug_url(get_java_version_info(ik, vmSymbols::java_runtime_vendor_vm_bug_url_name()));
 405   }
 406 
 407   // an instance of OutOfMemory exception has been allocated earlier
 408   initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
 409   initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
 410   initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
 411   initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
 412   initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
 413   initialize_class(vmSymbols::jdk_internal_vm_PreemptedException(), CHECK);
 414   initialize_class(vmSymbols::java_lang_ArrayIndexOutOfBoundsException(), CHECK);
 415   initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
 416   initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
 417   initialize_class(vmSymbols::java_lang_IdentityException(), CHECK);
 418   initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
 419   initialize_class(vmSymbols::java_lang_InternalError(), CHECK);
 420 }
 421 
 422 void Threads::initialize_jsr292_core_classes(TRAPS) {
 423   TraceTime timer("Initialize java.lang.invoke classes", TRACETIME_LOG(Info, startuptime));
 424 
 425   initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
 426   initialize_class(vmSymbols::java_lang_invoke_ResolvedMethodName(), CHECK);
 427   initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
 428   initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
 429 
 430   if (UseSharedSpaces) {
 431     HeapShared::initialize_java_lang_invoke(CHECK);
 432   }
 433 }
 434 
 435 // One-shot PeriodicTask subclass for reading the release file
 436 class ReadReleaseFileTask : public PeriodicTask {
 437  public:
 438   ReadReleaseFileTask() : PeriodicTask(100) {}
 439 
 440   virtual void task() {
 441     os::read_image_release_file();
 442 
 443     // Reclaim our storage and disenroll ourself.
 444     delete this;
 445   }
 446 };
 447 
 448 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
 449   extern void JDK_Version_init();
 450 
 451   // Preinitialize version info.
 452   VM_Version::early_initialize();
 453 
 454   // Check version
 455   if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
 456 
 457   // Deferred "static" initialization
 458   NonJavaThread::init();
 459 
 460   // Initialize library-based TLS
 461   ThreadLocalStorage::init();
 462 
 463   // Initialize the output stream module
 464   ostream_init();
 465 
 466   // Process java launcher properties.
 467   Arguments::process_sun_java_launcher_properties(args);
 468 
 469   // Initialize the os module
 470   os::init();
 471 
 472   // Initialize memory pools
 473   Arena::initialize_chunk_pool();
 474 
 475   MACOS_AARCH64_ONLY(os::current_thread_enable_wx(WXWrite));
 476 
 477   // Record VM creation timing statistics
 478   TraceVmCreationTime create_vm_timer;
 479   create_vm_timer.start();
 480 
 481   // Initialize system properties.
 482   Arguments::init_system_properties();
 483 
 484   // So that JDK version can be used as a discriminator when parsing arguments
 485   JDK_Version_init();
 486 
 487   // Update/Initialize System properties after JDK version number is known
 488   Arguments::init_version_specific_system_properties();
 489 
 490   // Make sure to initialize log configuration *before* parsing arguments
 491   LogConfiguration::initialize(create_vm_timer.begin_time());
 492 
 493   // Parse arguments
 494   // Note: this internally calls os::init_container_support()
 495   jint parse_result = Arguments::parse(args);
 496   if (parse_result != JNI_OK) return parse_result;
 497 
 498   // Initialize NMT right after argument parsing to keep the pre-NMT-init window small.
 499   MemTracker::initialize();
 500 
 501   os::init_before_ergo();
 502 
 503   jint ergo_result = Arguments::apply_ergo();
 504   if (ergo_result != JNI_OK) return ergo_result;
 505 
 506   // Final check of all ranges after ergonomics which may change values.
 507   if (!JVMFlagLimit::check_all_ranges()) {
 508     return JNI_EINVAL;
 509   }
 510 
 511   // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
 512   bool constraint_result = JVMFlagLimit::check_all_constraints(JVMFlagConstraintPhase::AfterErgo);
 513   if (!constraint_result) {
 514     return JNI_EINVAL;
 515   }
 516 
 517   if (PauseAtStartup) {
 518     os::pause();
 519   }
 520 
 521   HOTSPOT_VM_INIT_BEGIN();
 522 
 523   // Timing (must come after argument parsing)
 524   TraceTime timer("Create VM", TRACETIME_LOG(Info, startuptime));
 525 
 526   // Initialize the os module after parsing the args
 527   jint os_init_2_result = os::init_2();
 528   if (os_init_2_result != JNI_OK) return os_init_2_result;
 529 
 530 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT
 531   // Initialize assert poison page mechanism.
 532   if (ShowRegistersOnAssert) {
 533     initialize_assert_poison();
 534   }
 535 #endif // CAN_SHOW_REGISTERS_ON_ASSERT
 536 
 537   SafepointMechanism::initialize();
 538 
 539   jint adjust_after_os_result = Arguments::adjust_after_os();
 540   if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
 541 
 542   // Initialize output stream logging
 543   ostream_init_log();
 544 
 545   // Launch -agentlib/-agentpath and converted -Xrun agents
 546   JvmtiAgentList::load_agents();
 547 
 548   // Initialize Threads state
 549   _number_of_threads = 0;
 550   _number_of_non_daemon_threads = 0;
 551 
 552   // Initialize global data structures and create system classes in heap
 553   vm_init_globals();
 554 
 555   // Initialize OopStorage for threadObj
 556   JavaThread::_thread_oop_storage = OopStorageSet::create_strong("Thread OopStorage", mtThread);
 557 
 558   // Attach the main thread to this os thread. It is added to the threads list inside
 559   // universe_init(), within init_globals().
 560   JavaThread* main_thread = new JavaThread();
 561   main_thread->set_thread_state(_thread_in_vm);
 562   main_thread->initialize_thread_current();
 563   // Once mutexes and main_thread are ready, we can use NmtVirtualMemoryLocker.
 564   MemTracker::NmtVirtualMemoryLocker::set_safe_to_use();
 565   // must do this before set_active_handles
 566   main_thread->record_stack_base_and_size();
 567   main_thread->register_thread_stack_with_NMT();
 568   main_thread->set_active_handles(JNIHandleBlock::allocate_block());
 569   MACOS_AARCH64_ONLY(main_thread->init_wx());
 570 
 571   // Set the _monitor_owner_id now since we will run Java code before the Thread instance
 572   // is even created. The same value will be assigned to the Thread instance on init.
 573   const int64_t main_thread_tid = ThreadIdentifier::next();
 574   guarantee(main_thread_tid == 3, "Must equal the PRIMORDIAL_TID used in Threads.java");
 575   main_thread->set_monitor_owner_id(main_thread_tid);
 576 
 577   if (!Thread::set_as_starting_thread(main_thread)) {
 578     vm_shutdown_during_initialization(
 579                                       "Failed necessary internal allocation. Out of swap space");
 580     main_thread->smr_delete();
 581     *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
 582     return JNI_ENOMEM;
 583   }
 584 
 585   JFR_ONLY(Jfr::initialize_main_thread(main_thread);)
 586 
 587   // Enable guard page *after* os::create_main_thread(), otherwise it would
 588   // crash Linux VM, see notes in os_linux.cpp.
 589   main_thread->stack_overflow_state()->create_stack_guard_pages();
 590 
 591   // Initialize Java-Level synchronization subsystem
 592   ObjectMonitor::Initialize();
 593   ObjectSynchronizer::initialize();
 594 
 595   // Initialize global modules
 596   jint status = init_globals();
 597   if (status != JNI_OK) {
 598     main_thread->smr_delete();
 599     *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
 600     return status;
 601   }
 602 
 603   // Have the WatcherThread read the release file in the background.
 604   ReadReleaseFileTask* read_task = new ReadReleaseFileTask();
 605   read_task->enroll();
 606 
 607   // Create WatcherThread as soon as we can since we need it in case
 608   // of hangs during error reporting.
 609   WatcherThread::start();
 610 
 611   status = init_globals2();
 612   if (status != JNI_OK) {
 613     Threads::remove(main_thread, false);
 614     // It is possible that we managed to fully initialize Universe but have then
 615     // failed by throwing an exception. In that case our caller JNI_CreateJavaVM
 616     // will want to report it, so we can't delete the main thread.
 617     if (!main_thread->has_pending_exception()) {
 618       main_thread->smr_delete();
 619     }
 620     *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
 621     return status;
 622   }
 623 
 624   ObjectMonitor::Initialize2();
 625 
 626   JFR_ONLY(Jfr::on_create_vm_1();)
 627 
 628   // Should be done after the heap is fully created
 629   main_thread->cache_global_variables();
 630 
 631   // Any JVMTI raw monitors entered in onload will transition into
 632   // real raw monitor. VM is setup enough here for raw monitor enter.
 633   JvmtiExport::transition_pending_onload_raw_monitors();
 634 
 635   // Create the VMThread
 636   { TraceTime timer("Start VMThread", TRACETIME_LOG(Info, startuptime));
 637 
 638     VMThread::create();
 639     VMThread* vmthread = VMThread::vm_thread();
 640 
 641     if (!os::create_thread(vmthread, os::vm_thread)) {
 642       vm_exit_during_initialization("Cannot create VM thread. "
 643                                     "Out of system resources.");
 644     }
 645 
 646     // Wait for the VM thread to become ready, and VMThread::run to initialize
 647     // Monitors can have spurious returns, must always check another state flag
 648     {
 649       MonitorLocker ml(Notify_lock);
 650       os::start_thread(vmthread);
 651       while (!vmthread->is_running()) {
 652         ml.wait();
 653       }
 654     }
 655   }
 656 
 657   assert(Universe::is_fully_initialized(), "not initialized");
 658   if (VerifyDuringStartup) {
 659     // Make sure we're starting with a clean slate.
 660     VM_Verify verify_op;
 661     VMThread::execute(&verify_op);
 662   }
 663 
 664   // We need this to update the java.vm.info property in case any flags used
 665   // to initially define it have been changed. This is needed for both CDS
 666   // since UseSharedSpaces may be changed after java.vm.info
 667   // is initially computed. See Abstract_VM_Version::vm_info_string().
 668   // This update must happen before we initialize the java classes, but
 669   // after any initialization logic that might modify the flags.
 670   Arguments::update_vm_info_property(VM_Version::vm_info_string());
 671 
 672   JavaThread* THREAD = JavaThread::current(); // For exception macros.
 673   HandleMark hm(THREAD);
 674 
 675   // Always call even when there are not JVMTI environments yet, since environments
 676   // may be attached late and JVMTI must track phases of VM execution
 677   JvmtiExport::enter_early_start_phase();
 678 
 679   // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
 680   JvmtiExport::post_early_vm_start();
 681 
 682   // Launch -Xrun agents early if EagerXrunInit is set
 683   if (EagerXrunInit) {
 684     JvmtiAgentList::load_xrun_agents();
 685   }
 686 
 687   initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
 688 
 689   quicken_jni_functions();
 690 
 691   // No more stub generation allowed after that point.
 692   StubCodeDesc::freeze();
 693 
 694   // Prepare AOT heap loader for GC.
 695   HeapShared::enable_gc();
 696 
 697 #ifdef ADDRESS_SANITIZER
 698   Asan::initialize();
 699 #endif
 700 
 701   // Set flag that basic initialization has completed. Used by exceptions and various
 702   // debug stuff, that does not work until all basic classes have been initialized.
 703   set_init_completed();
 704 
 705   LogConfiguration::post_initialize();
 706   Metaspace::post_initialize();
 707   MutexLockerImpl::post_initialize();
 708 
 709   HOTSPOT_VM_INIT_END();
 710 
 711   // record VM initialization completion time
 712 #if INCLUDE_MANAGEMENT
 713   Management::record_vm_init_completed();
 714 #endif // INCLUDE_MANAGEMENT
 715 
 716   log_info(os)("Initialized VM with process ID %d", os::current_process_id());
 717 
 718   if (!FLAG_IS_DEFAULT(CreateCoredumpOnCrash) && CreateCoredumpOnCrash) {
 719     char buffer[2*JVM_MAXPATHLEN];
 720     os::check_core_dump_prerequisites(buffer, sizeof(buffer), true);
 721   }
 722 
 723   // Signal Dispatcher needs to be started before VMInit event is posted
 724   os::initialize_jdk_signal_support(CHECK_JNI_ERR);
 725 
 726   // Start Attach Listener if +StartAttachListener or it can't be started lazily
 727   if (!DisableAttachMechanism) {
 728     AttachListener::vm_start();
 729     if (StartAttachListener || AttachListener::init_at_startup()) {
 730       AttachListener::init();
 731     }
 732   }
 733 
 734   // Launch -Xrun agents if EagerXrunInit is not set.
 735   if (!EagerXrunInit) {
 736     JvmtiAgentList::load_xrun_agents();
 737   }
 738 
 739   Arena::start_chunk_pool_cleaner_task();
 740 
 741   // Start the service thread
 742   // The service thread enqueues JVMTI deferred events and does various hashtable
 743   // and other cleanups.  Needs to start before the compilers start posting events.
 744   ServiceThread::initialize();
 745 
 746   if (CDSConfig::is_using_aot_linked_classes()) {
 747     nmethod::post_delayed_compiled_method_load_events();
 748   }
 749 
 750   // Start the monitor deflation thread:
 751   MonitorDeflationThread::initialize();
 752 
 753   // initialize compiler(s)
 754 #if COMPILER1_OR_COMPILER2
 755   CompileBroker::compilation_init(CHECK_JNI_ERR);
 756 #endif // COMPILER1_OR_COMPILER2
 757 
 758   if (CDSConfig::is_using_aot_linked_classes()) {
 759     SystemDictionary::restore_archived_method_handle_intrinsics();
 760     AOTLinkedClassBulkLoader::init_javabase_classes(THREAD);
 761   }
 762 
 763   // Start string deduplication thread if requested.
 764   if (StringDedup::is_enabled()) {
 765     StringDedup::start();
 766   }
 767 
 768 #ifdef COMPILER2
 769   if (HotCodeHeap) {
 770     HotCodeCollector::initialize();
 771   }
 772 #endif // COMPILER2
 773 
 774   // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
 775   // It is done after compilers are initialized, because otherwise compilations of
 776   // signature polymorphic MH intrinsics can be missed
 777   // (see SystemDictionary::find_method_handle_intrinsic).
 778   initialize_jsr292_core_classes(CHECK_JNI_ERR);
 779 
 780   // This will initialize the module system.  Only java.base classes can be
 781   // loaded until phase 2 completes
 782   call_initPhase2(CHECK_JNI_ERR);
 783 
 784   if (CDSConfig::is_using_aot_linked_classes()) {
 785     AOTLinkedClassBulkLoader::init_non_javabase_classes(THREAD);
 786   }
 787 #ifndef PRODUCT
 788   HeapShared::initialize_test_class_from_archive(THREAD);
 789 #endif
 790 
 791   JFR_ONLY(Jfr::on_create_vm_2();)
 792 
 793   // Always call even when there are not JVMTI environments yet, since environments
 794   // may be attached late and JVMTI must track phases of VM execution
 795   JvmtiExport::enter_start_phase();
 796 
 797   // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
 798   JvmtiExport::post_vm_start();
 799 
 800   // Final system initialization including security manager and system class loader
 801   call_initPhase3(CHECK_JNI_ERR);
 802 
 803   // cache the system and platform class loaders
 804   SystemDictionary::compute_java_loaders(CHECK_JNI_ERR);
 805 
 806   // Initiate replay training processing once preloading is over.
 807   CompileBroker::init_training_replay();
 808 
 809   AOTLinkedClassBulkLoader::replay_training_at_init_for_preloaded_classes(CHECK_JNI_ERR);
 810 
 811   if (Continuations::enabled()) {
 812     // Initialize Continuation class now so that failure to create enterSpecial/doYield
 813     // special nmethods due to limited CodeCache size can be treated as a fatal error at
 814     // startup with the proper message that CodeCache size is too small.
 815     initialize_class(vmSymbols::jdk_internal_vm_Continuation(), CHECK_JNI_ERR);
 816   }
 817 
 818   if (NativeHeapTrimmer::enabled()) {
 819     NativeHeapTrimmer::initialize();
 820   }
 821 
 822   // Always call even when there are not JVMTI environments yet, since environments
 823   // may be attached late and JVMTI must track phases of VM execution
 824   JvmtiExport::enter_live_phase();
 825 
 826   // Make perfmemory accessible
 827   PerfMemory::set_accessible(true);
 828 
 829   // Notify JVMTI agents that VM initialization is complete - nop if no agents.
 830   JvmtiExport::post_vm_initialized();
 831 
 832   JFR_ONLY(Jfr::on_create_vm_3();)
 833 
 834 #if INCLUDE_MANAGEMENT
 835   bool start_agent = true;
 836 #if INCLUDE_CDS
 837   start_agent = !CDSConfig::is_dumping_final_static_archive();
 838   if (!start_agent) {
 839     log_info(aot)("Not starting management agent during creation of AOT cache.");
 840   }
 841 #endif // INCLUDE_CDS
 842   if (start_agent) {
 843     Management::initialize(THREAD);
 844 
 845     if (HAS_PENDING_EXCEPTION) {
 846       // management agent fails to start possibly due to
 847       // configuration problem and is responsible for printing
 848       // stack trace if appropriate. Simply exit VM.
 849       vm_exit(1);
 850     }
 851   }
 852 #endif // INCLUDE_MANAGEMENT
 853 
 854   if (UsePerfData)         PerfDataManager::create_misc_perfdata();
 855   if (CheckJNICalls)                  JniPeriodicChecker::engage();
 856 
 857   call_postVMInitHook(THREAD);
 858   // The Java side of PostVMInitHook.run must deal with all
 859   // exceptions and provide means of diagnosis.
 860   if (HAS_PENDING_EXCEPTION) {
 861     CLEAR_PENDING_EXCEPTION;
 862   }
 863 
 864   // Let WatcherThread run all registered periodic tasks now.
 865   // NOTE:  All PeriodicTasks should be registered by now. If they
 866   //   aren't, late joiners might appear to start slowly (we might
 867   //   take a while to process their first tick).
 868   WatcherThread::run_all_tasks();
 869 
 870   // Finish materializing AOT objects
 871   HeapShared::finish_materialize_objects();
 872 
 873   create_vm_timer.end();
 874 #ifdef ASSERT
 875   _vm_complete = true;
 876 #endif
 877 
 878   if (CDSConfig::is_dumping_classic_static_archive()) {
 879     // Classic -Xshare:dump, aka "old workflow"
 880     AOTMetaspace::dump_static_archive(CHECK_JNI_ERR);
 881   } else if (CDSConfig::is_dumping_final_static_archive()) {
 882     tty->print_cr("Reading AOTConfiguration %s and writing AOTCache %s", AOTConfiguration, AOTCache);
 883     AOTMetaspace::dump_static_archive(CHECK_JNI_ERR);
 884   }
 885 
 886   if (log_is_enabled(Info, perf, class, link)) {
 887     LogStreamHandle(Info, perf, class, link) log;
 888     log.print_cr("At VM initialization completion:");
 889     ClassLoader::print_counters(&log);
 890   }
 891 
 892   return JNI_OK;
 893 }
 894 
 895 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
 896 // the program falls off the end of main(). Another VM exit path is through
 897 // vm_exit(), when the program calls System.exit() to return a value, or when
 898 // there is a serious error in VM.
 899 // These two separate shutdown paths are not exactly the same, but they share
 900 // Shutdown.shutdown() at Java level and before_exit() and VM_Exit op at VM level.
 901 //
 902 // Shutdown sequence:
 903 //   + Shutdown native memory tracking if it is on
 904 //   + Wait until we are the last non-daemon thread to execute
 905 //     <-- every thing is still working at this moment -->
 906 //   + Call java.lang.Shutdown.shutdown(), which will invoke Java level
 907 //        shutdown hooks
 908 //   + Call before_exit(), prepare for VM exit
 909 //      > run VM level shutdown hooks (they are registered through JVM_OnExit(),
 910 //        currently the only user of this mechanism is File.deleteOnExit())
 911 //      > stop watcher thread,
 912 //        post thread end and vm death events to JVMTI,
 913 //        stop signal thread
 914 //   + Call JavaThread::exit(), it will:
 915 //      > release JNI handle blocks, remove stack guard pages
 916 //      > remove this thread from Threads list
 917 //     <-- no more Java code from this thread after this point -->
 918 //   + Stop VM thread, it will bring the remaining VM to a safepoint and stop
 919 //     the compiler threads at safepoint
 920 //     <-- do not use anything that could get blocked by Safepoint -->
 921 //   + Disable tracing at JNI/JVM barriers
 922 //   + Set _vm_exited flag for threads that are still running native code
 923 //   + Call exit_globals()
 924 //      > deletes tty
 925 //      > deletes PerfMemory resources
 926 //   + Delete this thread
 927 //   + Return to caller
 928 
 929 void Threads::destroy_vm() {
 930   JavaThread* thread = JavaThread::current();
 931 
 932 #ifdef ASSERT
 933   _vm_complete = false;
 934 #endif
 935   // Wait until we are the last non-daemon thread to execute, or
 936   // if we are a daemon then wait until the last non-daemon thread has
 937   // executed.
 938   bool daemon = java_lang_Thread::is_daemon(thread->threadObj());
 939   int expected = daemon ? 0 : 1;
 940   {
 941     MonitorLocker nu(Threads_lock);
 942     while (Threads::number_of_non_daemon_threads() > expected)
 943       // This wait should make safepoint checks, wait without a timeout.
 944       nu.wait(0);
 945   }
 946 
 947   EventShutdown e;
 948   if (e.should_commit()) {
 949     e.set_reason("No remaining non-daemon Java threads");
 950     e.commit();
 951   }
 952 
 953   // Hang forever on exit if we are reporting an error.
 954   if (ShowMessageBoxOnError && VMError::is_error_reported()) {
 955     os::infinite_sleep();
 956   }
 957   os::wait_for_keypress_at_exit();
 958 
 959   // run Java level shutdown hooks
 960   thread->invoke_shutdown_hooks();
 961 
 962   before_exit(thread);
 963 
 964   thread->exit(true);
 965 
 966   // We are no longer on the main thread list but could still be in a
 967   // secondary list where another thread may try to interact with us.
 968   // So wait until all such interactions are complete before we bring
 969   // the VM to the termination safepoint. Normally this would be done
 970   // using thread->smr_delete() below where we delete the thread, but
 971   // we can't call that after the termination safepoint is active as
 972   // we will deadlock on the Threads_lock. Once all interactions are
 973   // complete it is safe to directly delete the thread at any time.
 974   ThreadsSMRSupport::wait_until_not_protected(thread);
 975 
 976   // Stop VM thread.
 977   {
 978     // 4945125 The vm thread comes to a safepoint during exit.
 979     // GC vm_operations can get caught at the safepoint, and the
 980     // heap is unparseable if they are caught. Grab the Heap_lock
 981     // to prevent this. The GC vm_operations will not be able to
 982     // queue until after the vm thread is dead. After this point,
 983     // we'll never emerge out of the safepoint before the VM exits.
 984     // Assert that the thread is terminated so that acquiring the
 985     // Heap_lock doesn't cause the terminated thread to participate in
 986     // the safepoint protocol.
 987 
 988     assert(thread->is_terminated(), "must be terminated here");
 989     MutexLocker ml(Heap_lock);
 990 
 991     VMThread::wait_for_vm_thread_exit();
 992     assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
 993     VMThread::destroy();
 994   }
 995 
 996   // Now, all Java threads are gone except daemon threads. Daemon threads
 997   // running Java code or in VM are stopped by the Safepoint. However,
 998   // daemon threads executing native code are still running.  But they
 999   // will be stopped at native=>Java/VM barriers. Note that we can't
1000   // simply kill or suspend them, as it is inherently deadlock-prone.
1001 
1002   VM_Exit::set_vm_exited();
1003 
1004   // Clean up ideal graph printers after the VMThread has started
1005   // the final safepoint which will block all the Compiler threads.
1006   // Note that this Thread has already logically exited so the
1007   // clean_up() function's use of a JavaThreadIteratorWithHandle
1008   // would be a problem except set_vm_exited() has remembered the
1009   // shutdown thread which is granted a policy exception.
1010 #if defined(COMPILER2) && !defined(PRODUCT)
1011   IdealGraphPrinter::clean_up();
1012 #endif
1013 
1014   notify_vm_shutdown();
1015 
1016   // exit_globals() will delete tty
1017   exit_globals();
1018 
1019   // Deleting the shutdown thread here is safe. See comment on
1020   // wait_until_not_protected() above.
1021   delete thread;
1022 
1023   LogConfiguration::finalize();
1024 }
1025 
1026 
1027 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
1028   if (version == JNI_VERSION_1_1) return JNI_TRUE;
1029   return is_supported_jni_version(version);
1030 }
1031 
1032 
1033 jboolean Threads::is_supported_jni_version(jint version) {
1034   if (version == JNI_VERSION_1_2) return JNI_TRUE;
1035   if (version == JNI_VERSION_1_4) return JNI_TRUE;
1036   if (version == JNI_VERSION_1_6) return JNI_TRUE;
1037   if (version == JNI_VERSION_1_8) return JNI_TRUE;
1038   if (version == JNI_VERSION_9) return JNI_TRUE;
1039   if (version == JNI_VERSION_10) return JNI_TRUE;
1040   if (version == JNI_VERSION_19) return JNI_TRUE;
1041   if (version == JNI_VERSION_20) return JNI_TRUE;
1042   if (version == JNI_VERSION_21) return JNI_TRUE;
1043   if (version == JNI_VERSION_24) return JNI_TRUE;
1044   if (version == JNI_VERSION_28) return JNI_TRUE;
1045   return JNI_FALSE;
1046 }
1047 
1048 void Threads::add(JavaThread* p, bool force_daemon) {
1049   // The threads lock must be owned at this point
1050   assert(Threads_lock->owned_by_self(), "must have threads lock");
1051   assert(p->monitor_owner_id() != 0, "should be set");
1052 
1053   BarrierSet::barrier_set()->on_thread_attach(p);
1054 
1055   // Once a JavaThread is added to the Threads list, smr_delete() has
1056   // to be used to delete it. Otherwise we can just delete it directly.
1057   p->set_on_thread_list();
1058 
1059   _number_of_threads++;
1060   oop threadObj = p->threadObj();
1061   bool daemon = true;
1062   // Bootstrapping problem: threadObj can be null for initial
1063   // JavaThread (or for threads attached via JNI)
1064   if (!force_daemon &&
1065       (threadObj == nullptr || !java_lang_Thread::is_daemon(threadObj))) {
1066     _number_of_non_daemon_threads++;
1067     daemon = false;
1068   }
1069 
1070   ThreadService::add_thread(p, daemon);
1071 
1072   // Maintain fast thread list
1073   ThreadsSMRSupport::add_thread(p);
1074 
1075   // Increase the ObjectMonitor ceiling for the new thread.
1076   ObjectSynchronizer::inc_in_use_list_ceiling();
1077 
1078   // Possible GC point.
1079   Events::log(Thread::current(), "Thread added: " INTPTR_FORMAT, p2i(p));
1080 
1081   // Make new thread known to active EscapeBarrier
1082   EscapeBarrier::thread_added(p);
1083 }
1084 
1085 void Threads::remove(JavaThread* p, bool is_daemon) {
1086   // Extra scope needed for Thread_lock, so we can check
1087   // that we do not remove thread without safepoint code notice
1088   {
1089     ConditionalMutexLocker throttle_ml(ThreadsLockThrottle_lock, UseThreadsLockThrottleLock);
1090     MonitorLocker ml(Threads_lock);
1091 
1092     if (ThreadIdTable::is_initialized_acquire()) {
1093       // This cleanup must be done before the current thread's GC barrier
1094       // is detached since we need to touch the threadObj oop.
1095       jlong tid = SharedRuntime::get_java_tid(p);
1096       ThreadIdTable::remove_thread(tid);
1097     }
1098 
1099     // BarrierSet state must be destroyed after the last thread transition
1100     // before the thread terminates. Thread transitions result in calls to
1101     // StackWatermarkSet::on_safepoint(), which performs GC processing,
1102     // requiring the GC state to be alive.
1103     BarrierSet::barrier_set()->on_thread_detach(p);
1104     if (p->is_exiting()) {
1105       // If we got here via JavaThread::exit(), then we remember that the
1106       // thread's GC barrier has been detached. We don't do this when we get
1107       // here from another path, e.g., cleanup_failed_attach_current_thread().
1108       p->set_terminated(JavaThread::_thread_gc_barrier_detached);
1109     }
1110 
1111     assert(ThreadsSMRSupport::get_java_thread_list()->includes(p), "p must be present");
1112 
1113     // Maintain fast thread list
1114     ThreadsSMRSupport::remove_thread(p);
1115 
1116     _number_of_threads--;
1117     if (!is_daemon) {
1118       _number_of_non_daemon_threads--;
1119 
1120       // If this is the last non-daemon thread then we need to do
1121       // a notify on the Threads_lock so a thread waiting
1122       // on destroy_vm will wake up. But that thread could be a daemon
1123       // or non-daemon, so we notify for both the 0 and 1 case.
1124       if (number_of_non_daemon_threads() <= 1) {
1125         ml.notify_all();
1126       }
1127     }
1128     ThreadService::remove_thread(p, is_daemon);
1129 
1130     // Make sure that safepoint code disregard this thread. This is needed since
1131     // the thread might mess around with locks after this point. This can cause it
1132     // to do callbacks into the safepoint code. However, the safepoint code is not aware
1133     // of this thread since it is removed from the queue.
1134     p->set_terminated(JavaThread::_thread_terminated);
1135 
1136     // Notify threads waiting in EscapeBarriers
1137     EscapeBarrier::thread_removed(p);
1138   } // unlock Threads_lock and ThreadsLockThrottle_lock
1139 
1140   // Reduce the ObjectMonitor ceiling for the exiting thread.
1141   ObjectSynchronizer::dec_in_use_list_ceiling();
1142 
1143   // Since Events::log uses a lock, we grab it outside the Threads_lock
1144   Events::log(Thread::current(), "Thread exited: " INTPTR_FORMAT, p2i(p));
1145 }
1146 
1147 // Operations on the Threads list for GC.  These are not explicitly locked,
1148 // but the garbage collector must provide a safe context for them to run.
1149 // In particular, these things should never be called when the Threads_lock
1150 // is held by some other thread. (Note: the Safepoint abstraction also
1151 // uses the Threads_lock to guarantee this property. It also makes sure that
1152 // all threads gets blocked when exiting or starting).
1153 
1154 void Threads::oops_do(OopClosure* f, NMethodClosure* cf) {
1155   ALL_JAVA_THREADS(p) {
1156     p->oops_do(f, cf);
1157   }
1158   VMThread::vm_thread()->oops_do(f, cf);
1159 }
1160 
1161 void Threads::change_thread_claim_token() {
1162   if (++_thread_claim_token == 0) {
1163     // On overflow of the token counter, there is a risk of future
1164     // collisions between a new global token value and a stale token
1165     // for a thread, because not all iterations visit all threads.
1166     // (Though it's pretty much a theoretical concern for non-trivial
1167     // token counter sizes.)  To deal with the possibility, reset all
1168     // the thread tokens to zero on global token overflow.
1169     struct ResetClaims : public ThreadClosure {
1170       virtual void do_thread(Thread* t) {
1171         t->claim_threads_do(false, 0);
1172       }
1173     } reset_claims;
1174     Threads::threads_do(&reset_claims);
1175     // On overflow, update the global token to non-zero, to
1176     // avoid the special "never claimed" initial thread value.
1177     _thread_claim_token = 1;
1178   }
1179 }
1180 
1181 #ifdef ASSERT
1182 static void assert_thread_claimed(const char* kind, Thread* t, uintx expected) {
1183   const uintx token = t->threads_do_token();
1184   assert(token == expected,
1185          "%s " PTR_FORMAT " has incorrect value %zu != %zu",
1186          kind, p2i(t), token, expected);
1187 }
1188 
1189 void Threads::assert_all_threads_claimed() {
1190   ALL_JAVA_THREADS(p) {
1191     assert_thread_claimed("JavaThread", p, _thread_claim_token);
1192   }
1193 
1194   struct NJTClaimedVerifierClosure : public ThreadClosure {
1195     uintx _thread_claim_token;
1196 
1197     NJTClaimedVerifierClosure(uintx thread_claim_token) : ThreadClosure(), _thread_claim_token(thread_claim_token) { }
1198 
1199     virtual void do_thread(Thread* thread) override {
1200       assert_thread_claimed("Non-JavaThread", VMThread::vm_thread(), _thread_claim_token);
1201     }
1202   } tc(_thread_claim_token);
1203 
1204   non_java_threads_do(&tc);
1205 }
1206 #endif // ASSERT
1207 
1208 class ParallelOopsDoThreadClosure : public ThreadClosure {
1209 private:
1210   OopClosure* _f;
1211   NMethodClosure* _cf;
1212 public:
1213   ParallelOopsDoThreadClosure(OopClosure* f, NMethodClosure* cf) : _f(f), _cf(cf) {}
1214   void do_thread(Thread* t) {
1215     t->oops_do(_f, _cf);
1216   }
1217 };
1218 
1219 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, NMethodClosure* cf) {
1220   ParallelOopsDoThreadClosure tc(f, cf);
1221   possibly_parallel_threads_do(is_par, &tc);
1222 }
1223 
1224 void Threads::metadata_do(MetadataClosure* f) {
1225   ALL_JAVA_THREADS(p) {
1226     p->metadata_do(f);
1227   }
1228 }
1229 
1230 class ThreadHandlesClosure : public ThreadClosure {
1231   void (*_f)(Metadata*);
1232  public:
1233   ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
1234   virtual void do_thread(Thread* thread) {
1235     thread->metadata_handles_do(_f);
1236   }
1237 };
1238 
1239 void Threads::metadata_handles_do(void f(Metadata*)) {
1240   // Only walk the Handles in Thread.
1241   ThreadHandlesClosure handles_closure(f);
1242   threads_do(&handles_closure);
1243 }
1244 
1245 #if INCLUDE_JVMTI
1246 // Get Java threads that are waiting to enter or re-enter the specified monitor.
1247 // Java threads that are executing mounted virtual threads are not included.
1248 GrowableArray<JavaThread*>* Threads::get_pending_threads(ThreadsList * t_list,
1249                                                          int count,
1250                                                          address monitor) {
1251   assert(Thread::current()->is_VM_thread(), "Must be the VM thread");
1252   GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
1253 
1254   int i = 0;
1255   for (JavaThread* p : *t_list) {
1256     if (!p->can_call_java()) continue;
1257 
1258     oop thread_oop = JvmtiEnvBase::get_vthread_or_thread_oop(p);
1259     if (thread_oop->is_a(vmClasses::BaseVirtualThread_klass())) {
1260       continue;
1261     }
1262     // The first stage of async deflation does not affect any field
1263     // used by this comparison so the ObjectMonitor* is usable here.
1264     address pending = (address)p->current_pending_monitor();
1265     address waiting = (address)p->current_waiting_monitor();
1266     // do not include virtual threads to the list
1267     jint state = JvmtiEnvBase::get_thread_state(thread_oop, p);
1268     if (pending == monitor || (waiting == monitor &&
1269         (state & JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER))
1270     ) { // found a match
1271       if (i < count) result->append(p);   // save the first count matches
1272       i++;
1273     }
1274   }
1275 
1276   return result;
1277 }
1278 #endif // INCLUDE_JVMTI
1279 
1280 JavaThread* Threads::owning_thread_from_object(ThreadsList * t_list, oop obj) {
1281   for (JavaThread* q : *t_list) {
1282     // Need to start processing before accessing oops in the thread.
1283     StackWatermark* watermark = StackWatermarkSet::get(q, StackWatermarkKind::gc);
1284     if (watermark != nullptr) {
1285       watermark->start_processing();
1286     }
1287 
1288     if (q->lock_stack().contains(obj)) {
1289       return q;
1290     }
1291   }
1292   return nullptr;
1293 }
1294 
1295 JavaThread* Threads::owning_thread_from_monitor(ThreadsList* t_list, ObjectMonitor* monitor) {
1296   if (monitor->has_anonymous_owner()) {
1297     return owning_thread_from_object(t_list, monitor->object());
1298   } else {
1299     JavaThread* the_owner = nullptr;
1300     for (JavaThread* q : *t_list) {
1301       if (monitor->has_owner(q)) {
1302         the_owner = q;
1303         break;
1304       }
1305     }
1306     return the_owner;
1307   }
1308 }
1309 
1310 class PrintOnClosure : public ThreadClosure {
1311 private:
1312   outputStream* _st;
1313 
1314 public:
1315   PrintOnClosure(outputStream* st) :
1316       _st(st) {}
1317 
1318   virtual void do_thread(Thread* thread) {
1319     if (thread != nullptr) {
1320       thread->print_on(_st);
1321       _st->cr();
1322     }
1323   }
1324 };
1325 
1326 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
1327 void Threads::print_on(outputStream* st, bool print_stacks,
1328                        bool internal_format, bool print_concurrent_locks,
1329                        bool print_extended_info) {
1330   char buf[32];
1331   st->print_raw_cr(os::local_time_string(buf, sizeof(buf)));
1332 
1333   st->print_cr("Full thread dump %s (%s %s)",
1334                VM_Version::vm_name(),
1335                VM_Version::vm_release(),
1336                VM_Version::vm_info_string());
1337   JDK_Version::current().to_string(buf, sizeof(buf));
1338   const char* runtime_name = JDK_Version::runtime_name() != nullptr ?
1339                              JDK_Version::runtime_name() : "";
1340   const char* runtime_version = JDK_Version::runtime_version() != nullptr ?
1341                                 JDK_Version::runtime_version() : "";
1342   const char* vendor_version = JDK_Version::runtime_vendor_version() != nullptr ?
1343                                JDK_Version::runtime_vendor_version() : "";
1344   const char* jdk_debug_level = VM_Version::printable_jdk_debug_level() != nullptr ?
1345                                 VM_Version::printable_jdk_debug_level() : "";
1346 
1347   st->print_cr("                 JDK version: %s%s%s (%s) (%sbuild %s)", runtime_name,
1348                 (*vendor_version != '\0') ? " " : "", vendor_version,
1349                 buf, jdk_debug_level, runtime_version);
1350 
1351   st->cr();
1352 
1353 #if INCLUDE_SERVICES
1354   // Dump concurrent locks
1355   ConcurrentLocksDump concurrent_locks;
1356   if (print_concurrent_locks) {
1357     concurrent_locks.dump_at_safepoint();
1358   }
1359 #endif // INCLUDE_SERVICES
1360 
1361   ThreadsSMRSupport::print_info_on(st);
1362   st->cr();
1363 
1364   ALL_JAVA_THREADS(p) {
1365     ResourceMark rm;
1366     p->print_on(st, print_extended_info);
1367     if (print_stacks) {
1368       if (internal_format) {
1369         p->trace_stack();
1370       } else {
1371         p->print_stack_on(st);
1372         if (p->is_vthread_mounted()) {
1373           st->print_cr("   Mounted virtual thread #" INT64_FORMAT, java_lang_Thread::thread_id(p->vthread()));
1374           p->print_vthread_stack_on(st);
1375         }
1376       }
1377     }
1378     st->cr();
1379 #if INCLUDE_SERVICES
1380     if (print_concurrent_locks) {
1381       concurrent_locks.print_locks_on(p, st);
1382     }
1383 #endif // INCLUDE_SERVICES
1384   }
1385 
1386   PrintOnClosure cl(st);
1387   non_java_threads_do(&cl);
1388 
1389   st->flush();
1390 }
1391 
1392 void Threads::print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
1393                              int buflen, bool* found_current) {
1394   if (this_thread != nullptr) {
1395     bool is_current = (current == this_thread);
1396     *found_current = *found_current || is_current;
1397     st->print("%s", is_current ? "=>" : "  ");
1398 
1399     st->print(PTR_FORMAT, p2i(this_thread));
1400     st->print(" ");
1401     this_thread->print_on_error(st, buf, buflen);
1402     st->cr();
1403   }
1404 }
1405 
1406 class PrintOnErrorClosure : public ThreadClosure {
1407   outputStream* _st;
1408   Thread* _current;
1409   char* _buf;
1410   int _buflen;
1411   bool* _found_current;
1412   unsigned _num_printed;
1413  public:
1414   PrintOnErrorClosure(outputStream* st, Thread* current, char* buf,
1415                       int buflen, bool* found_current) :
1416    _st(st), _current(current), _buf(buf), _buflen(buflen), _found_current(found_current),
1417    _num_printed(0) {}
1418 
1419   virtual void do_thread(Thread* thread) {
1420     _num_printed++;
1421     Threads::print_on_error(thread, _st, _current, _buf, _buflen, _found_current);
1422   }
1423 
1424   unsigned num_printed() const { return _num_printed; }
1425 };
1426 
1427 // Threads::print_on_error() is called by fatal error handler. It's possible
1428 // that VM is not at safepoint and/or current thread is inside signal handler.
1429 // Don't print stack trace, as the stack may not be walkable. Don't allocate
1430 // memory (even in resource area), it might deadlock the error handler.
1431 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
1432                              int buflen) {
1433   ThreadsSMRSupport::print_info_on(st);
1434   st->cr();
1435 
1436   bool found_current = false;
1437   st->print_cr("Java Threads: ( => current thread )");
1438   unsigned num_java = 0;
1439   ALL_JAVA_THREADS(thread) {
1440     print_on_error(thread, st, current, buf, buflen, &found_current);
1441     num_java++;
1442   }
1443   st->print_cr("Total: %u", num_java);
1444   st->cr();
1445 
1446   st->print_cr("Other Threads:");
1447   unsigned num_other = ((VMThread::vm_thread() != nullptr) ? 1 : 0) +
1448       ((WatcherThread::watcher_thread() != nullptr) ? 1 : 0) +
1449       ((AsyncLogWriter::instance() != nullptr)  ? 1 : 0);
1450   print_on_error(VMThread::vm_thread(), st, current, buf, buflen, &found_current);
1451   print_on_error(WatcherThread::watcher_thread(), st, current, buf, buflen, &found_current);
1452   print_on_error(AsyncLogWriter::instance(), st, current, buf, buflen, &found_current);
1453 
1454   if (Universe::heap() != nullptr) {
1455     PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current);
1456     Universe::heap()->gc_threads_do(&print_closure);
1457     num_other += print_closure.num_printed();
1458   }
1459 
1460   if (!found_current) {
1461     st->cr();
1462     st->print("=>" PTR_FORMAT " (exited) ", p2i(current));
1463     current->print_on_error(st, buf, buflen);
1464     num_other++;
1465     st->cr();
1466   }
1467   st->print_cr("Total: %u", num_other);
1468   st->cr();
1469 
1470   st->print_cr("Threads with active compile tasks:");
1471   unsigned num = print_threads_compiling(st, buf, buflen);
1472   st->print_cr("Total: %u", num);
1473 }
1474 
1475 unsigned Threads::print_threads_compiling(outputStream* st, char* buf, int buflen, bool short_form) {
1476   unsigned num = 0;
1477   ALL_JAVA_THREADS(thread) {
1478     if (thread->is_Compiler_thread()) {
1479       CompilerThread* ct = (CompilerThread*) thread;
1480 
1481       // Keep task in local variable for null check.
1482       // ct->_task might be set to null by concurring compiler thread
1483       // because it completed the compilation. The task is never freed,
1484       // though, just returned to a free list.
1485       CompileTask* task = ct->task();
1486       if (task != nullptr) {
1487         thread->print_name_on_error(st, buf, buflen);
1488         st->print("  ");
1489         task->print(st, nullptr, short_form, true);
1490         num++;
1491       }
1492     }
1493   }
1494   return num;
1495 }
1496 
1497 void Threads::verify() {
1498   ALL_JAVA_THREADS(p) {
1499     p->verify();
1500   }
1501   VMThread* thread = VMThread::vm_thread();
1502   if (thread != nullptr) thread->verify();
1503 }