1 /*
   2  * Copyright (c) 1997, 2025, 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.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/dtrace.hpp"
 106 #include "utilities/events.hpp"
 107 #include "utilities/macros.hpp"
 108 #include "utilities/vmError.hpp"
 109 #if INCLUDE_JVMCI
 110 #include "jvmci/jvmci.hpp"
 111 #include "jvmci/jvmciEnv.hpp"
 112 #endif
 113 #ifdef COMPILER2
 114 #include "opto/idealGraphPrinter.hpp"
 115 #endif
 116 #if INCLUDE_JFR
 117 #include "jfr/jfr.hpp"
 118 #endif
 119 
 120 // Initialization after module runtime initialization
 121 void universe_post_module_init();  // must happen after call_initPhase2
 122 
 123 
 124 static void initialize_class(Symbol* class_name, TRAPS) {
 125   Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
 126   InstanceKlass::cast(klass)->initialize(CHECK);
 127 }
 128 
 129 
 130 // Creates the initial ThreadGroup
 131 static Handle create_initial_thread_group(TRAPS) {
 132   Handle system_instance = JavaCalls::construct_new_instance(
 133                             vmClasses::ThreadGroup_klass(),
 134                             vmSymbols::void_method_signature(),
 135                             CHECK_NH);
 136   Universe::set_system_thread_group(system_instance());
 137 
 138   Handle string = java_lang_String::create_from_str("main", CHECK_NH);
 139   Handle main_instance = JavaCalls::construct_new_instance(
 140                             vmClasses::ThreadGroup_klass(),
 141                             vmSymbols::threadgroup_string_void_signature(),
 142                             system_instance,
 143                             string,
 144                             CHECK_NH);
 145   return main_instance;
 146 }
 147 
 148 // Creates the initial Thread, and sets it to running.
 149 static void create_initial_thread(Handle thread_group, JavaThread* thread,
 150                                  TRAPS) {
 151   InstanceKlass* ik = vmClasses::Thread_klass();
 152   assert(ik->is_initialized(), "must be");
 153   instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
 154 
 155   // Cannot use JavaCalls::construct_new_instance because the java.lang.Thread
 156   // constructor calls Thread.current(), which must be set here for the
 157   // initial thread.
 158   java_lang_Thread::set_thread(thread_oop(), thread);
 159   thread->set_threadOopHandles(thread_oop());
 160 
 161   Handle string = java_lang_String::create_from_str("main", CHECK);
 162 
 163   JavaValue result(T_VOID);
 164   JavaCalls::call_special(&result, thread_oop,
 165                           ik,
 166                           vmSymbols::object_initializer_name(),
 167                           vmSymbols::threadgroup_string_void_signature(),
 168                           thread_group,
 169                           string,
 170                           CHECK);
 171 
 172   DEBUG_ONLY(int64_t main_thread_tid = java_lang_Thread::thread_id(thread_oop());)
 173   assert(main_thread_tid == ThreadIdentifier::initial(), "");
 174   assert(main_thread_tid == thread->monitor_owner_id(), "");
 175   JFR_ONLY(assert(JFR_JVM_THREAD_ID(thread) == static_cast<traceid>(main_thread_tid), "initial tid mismatch");)
 176 
 177   // Set thread status to running since main thread has
 178   // been started and running.
 179   java_lang_Thread::set_thread_status(thread_oop(),
 180                                       JavaThreadStatus::RUNNABLE);
 181 }
 182 
 183 // Extract version and vendor specific information from
 184 // java.lang.VersionProps fields.
 185 // Returned char* is allocated in the thread's resource area
 186 // so must be copied for permanency.
 187 static const char* get_java_version_info(InstanceKlass* ik,
 188                                          Symbol* field_name) {
 189   fieldDescriptor fd;
 190   bool found = ik != nullptr &&
 191                ik->find_local_field(field_name,
 192                                     vmSymbols::string_signature(), &fd);
 193   if (found) {
 194     oop name_oop = ik->java_mirror()->obj_field(fd.offset());
 195     if (name_oop == nullptr) {
 196       return nullptr;
 197     }
 198     const char* name = java_lang_String::as_utf8_string(name_oop);
 199     return name;
 200   } else {
 201     return nullptr;
 202   }
 203 }
 204 
 205 // ======= Threads ========
 206 
 207 // The Threads class links together all active threads, and provides
 208 // operations over all threads. It is protected by the Threads_lock,
 209 // which is also used in other global contexts like safepointing.
 210 // ThreadsListHandles are used to safely perform operations on one
 211 // or more threads without the risk of the thread exiting during the
 212 // operation.
 213 //
 214 // Note: The Threads_lock is currently more widely used than we
 215 // would like. We are actively migrating Threads_lock uses to other
 216 // mechanisms in order to reduce Threads_lock contention.
 217 
 218 int         Threads::_number_of_threads = 0;
 219 int         Threads::_number_of_non_daemon_threads = 0;
 220 int         Threads::_return_code = 0;
 221 uintx       Threads::_thread_claim_token = 1; // Never zero.
 222 
 223 #ifdef ASSERT
 224 bool        Threads::_vm_complete = false;
 225 #endif
 226 
 227 // General purpose hook into Java code, run once when the VM is initialized.
 228 // The Java library method itself may be changed independently from the VM.
 229 static void call_postVMInitHook(TRAPS) {
 230   Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_vm_PostVMInitHook(), THREAD);
 231   if (klass != nullptr) {
 232     JavaValue result(T_VOID);
 233     JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
 234                            vmSymbols::void_method_signature(),
 235                            CHECK);
 236   }
 237 }
 238 
 239 // All NonJavaThreads (i.e., every non-JavaThread in the system).
 240 void Threads::non_java_threads_do(ThreadClosure* tc) {
 241   NoSafepointVerifier nsv;
 242   for (NonJavaThread::Iterator njti; !njti.end(); njti.step()) {
 243     tc->do_thread(njti.current());
 244   }
 245 }
 246 
 247 // All JavaThreads
 248 #define ALL_JAVA_THREADS(X) \
 249   for (JavaThread* X : *ThreadsSMRSupport::get_java_thread_list())
 250 
 251 // All JavaThreads
 252 void Threads::java_threads_do(ThreadClosure* tc) {
 253   assert_locked_or_safepoint(Threads_lock);
 254   // ALL_JAVA_THREADS iterates through all JavaThreads.
 255   ALL_JAVA_THREADS(p) {
 256     tc->do_thread(p);
 257   }
 258 }
 259 
 260 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system).
 261 void Threads::threads_do(ThreadClosure* tc) {
 262   assert_locked_or_safepoint(Threads_lock);
 263   java_threads_do(tc);
 264   non_java_threads_do(tc);
 265 }
 266 
 267 void Threads::possibly_parallel_threads_do(bool is_par, ThreadClosure* tc) {
 268   assert_at_safepoint();
 269 
 270   uintx claim_token = Threads::thread_claim_token();
 271   ALL_JAVA_THREADS(p) {
 272     if (p->claim_threads_do(is_par, claim_token)) {
 273       tc->do_thread(p);
 274     }
 275   }
 276   for (NonJavaThread::Iterator njti; !njti.end(); njti.step()) {
 277     Thread* current = njti.current();
 278     if (current->claim_threads_do(is_par, claim_token)) {
 279       tc->do_thread(current);
 280     }
 281   }
 282 }
 283 
 284 // The system initialization in the library has three phases.
 285 //
 286 // Phase 1: java.lang.System class initialization
 287 //     java.lang.System is a primordial class loaded and initialized
 288 //     by the VM early during startup.  java.lang.System.<clinit>
 289 //     only does registerNatives and keeps the rest of the class
 290 //     initialization work later until thread initialization completes.
 291 //
 292 //     System.initPhase1 initializes the system properties, the static
 293 //     fields in, out, and err. Set up java signal handlers, OS-specific
 294 //     system settings, and thread group of the main thread.
 295 static void call_initPhase1(TRAPS) {
 296   Klass* klass = vmClasses::System_klass();
 297   JavaValue result(T_VOID);
 298   JavaCalls::call_static(&result, klass, vmSymbols::initPhase1_name(),
 299                                          vmSymbols::void_method_signature(), CHECK);
 300 }
 301 
 302 // Phase 2. Module system initialization
 303 //     This will initialize the module system.  Only java.base classes
 304 //     can be loaded until phase 2 completes.
 305 //
 306 //     Call System.initPhase2 after the compiler initialization and jsr292
 307 //     classes get initialized because module initialization runs a lot of java
 308 //     code, that for performance reasons, should be compiled.  Also, this will
 309 //     enable the startup code to use lambda and other language features in this
 310 //     phase and onward.
 311 //
 312 //     After phase 2, The VM will begin search classes from -Xbootclasspath/a.
 313 static void call_initPhase2(TRAPS) {
 314   TraceTime timer("Initialize module system", TRACETIME_LOG(Info, startuptime));
 315 
 316   Klass* klass = vmClasses::System_klass();
 317 
 318   JavaValue result(T_INT);
 319   JavaCallArguments args;
 320   args.push_int(DisplayVMOutputToStderr);
 321   args.push_int(log_is_enabled(Debug, init)); // print stack trace if exception thrown
 322   JavaCalls::call_static(&result, klass, vmSymbols::initPhase2_name(),
 323                                          vmSymbols::boolean_boolean_int_signature(), &args, CHECK);
 324   if (result.get_jint() != JNI_OK) {
 325     vm_exit_during_initialization(); // no message or exception
 326   }
 327 
 328   universe_post_module_init();
 329 }
 330 
 331 // Phase 3. final setup - set security manager, system class loader and TCCL
 332 //
 333 //     This will instantiate and set the security manager, set the system class
 334 //     loader as well as the thread context class loader.  The security manager
 335 //     and system class loader may be a custom class loaded from -Xbootclasspath/a,
 336 //     other modules or the application's classpath.
 337 static void call_initPhase3(TRAPS) {
 338   Klass* klass = vmClasses::System_klass();
 339   JavaValue result(T_VOID);
 340   JavaCalls::call_static(&result, klass, vmSymbols::initPhase3_name(),
 341                                          vmSymbols::void_method_signature(), CHECK);
 342 }
 343 
 344 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
 345   TraceTime timer("Initialize java.lang classes", TRACETIME_LOG(Info, startuptime));
 346 
 347   // This is before the execution of the very first Java bytecode.
 348   if (CDSConfig::is_using_aot_linked_classes()) {
 349     AOTLinkedClassBulkLoader::link_classes(THREAD);
 350   }
 351 
 352   initialize_class(vmSymbols::java_lang_String(), CHECK);
 353 
 354   // Inject CompactStrings value after the static initializers for String ran.
 355   java_lang_String::set_compact_strings(CompactStrings);
 356 
 357   // Initialize java_lang.System (needed before creating the thread)
 358   initialize_class(vmSymbols::java_lang_System(), CHECK);
 359   // The VM creates & returns objects of this class. Make sure it's initialized.
 360   initialize_class(vmSymbols::java_lang_Class(), CHECK);
 361 
 362   initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
 363   Handle thread_group = create_initial_thread_group(CHECK);
 364   Universe::set_main_thread_group(thread_group());
 365   initialize_class(vmSymbols::java_lang_Thread(), CHECK);
 366   create_initial_thread(thread_group, main_thread, CHECK);
 367 
 368   HeapShared::init_box_classes(CHECK);
 369 
 370   // The VM creates objects of this class.
 371   initialize_class(vmSymbols::java_lang_Module(), CHECK);
 372 
 373 #ifdef ASSERT
 374   InstanceKlass *k = vmClasses::UnsafeConstants_klass();
 375   assert(k->is_not_initialized(), "UnsafeConstants should not already be initialized");
 376 #endif
 377 
 378   // initialize the hardware-specific constants needed by Unsafe
 379   initialize_class(vmSymbols::jdk_internal_misc_UnsafeConstants(), CHECK);
 380   jdk_internal_misc_UnsafeConstants::set_unsafe_constants();
 381 
 382   // The VM preresolves methods to these classes. Make sure that they get initialized
 383   initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
 384   initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
 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::java_lang_ArrayIndexOutOfBoundsException(), CHECK);
 414   initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
 415   initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
 416   initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
 417   initialize_class(vmSymbols::java_lang_InternalError(), CHECK);
 418 }
 419 
 420 void Threads::initialize_jsr292_core_classes(TRAPS) {
 421   TraceTime timer("Initialize java.lang.invoke classes", TRACETIME_LOG(Info, startuptime));
 422 
 423   initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
 424   initialize_class(vmSymbols::java_lang_invoke_ResolvedMethodName(), CHECK);
 425   initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
 426   initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
 427 
 428   if (UseSharedSpaces) {
 429     HeapShared::initialize_java_lang_invoke(CHECK);
 430   }
 431 }
 432 
 433 // One-shot PeriodicTask subclass for reading the release file
 434 class ReadReleaseFileTask : public PeriodicTask {
 435  public:
 436   ReadReleaseFileTask() : PeriodicTask(100) {}
 437 
 438   virtual void task() {
 439     os::read_image_release_file();
 440 
 441     // Reclaim our storage and disenroll ourself.
 442     delete this;
 443   }
 444 };
 445 
 446 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
 447   extern void JDK_Version_init();
 448 
 449   // Preinitialize version info.
 450   VM_Version::early_initialize();
 451 
 452   // Check version
 453   if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
 454 
 455   // Deferred "static" initialization
 456   NonJavaThread::init();
 457 
 458   // Initialize library-based TLS
 459   ThreadLocalStorage::init();
 460 
 461   // Initialize the output stream module
 462   ostream_init();
 463 
 464   // Process java launcher properties.
 465   Arguments::process_sun_java_launcher_properties(args);
 466 
 467   // Initialize the os module
 468   os::init();
 469 
 470   // Initialize memory pools
 471   Arena::initialize_chunk_pool();
 472 
 473   MACOS_AARCH64_ONLY(os::current_thread_enable_wx(WXWrite));
 474 
 475   // Record VM creation timing statistics
 476   TraceVmCreationTime create_vm_timer;
 477   create_vm_timer.start();
 478 
 479   // Initialize system properties.
 480   Arguments::init_system_properties();
 481 
 482   // So that JDK version can be used as a discriminator when parsing arguments
 483   JDK_Version_init();
 484 
 485   // Update/Initialize System properties after JDK version number is known
 486   Arguments::init_version_specific_system_properties();
 487 
 488   // Make sure to initialize log configuration *before* parsing arguments
 489   LogConfiguration::initialize(create_vm_timer.begin_time());
 490 
 491   // Parse arguments
 492   // Note: this internally calls os::init_container_support()
 493   jint parse_result = Arguments::parse(args);
 494   if (parse_result != JNI_OK) return parse_result;
 495 
 496   // Initialize NMT right after argument parsing to keep the pre-NMT-init window small.
 497   MemTracker::initialize();
 498 
 499   os::init_before_ergo();
 500 
 501   jint ergo_result = Arguments::apply_ergo();
 502   if (ergo_result != JNI_OK) return ergo_result;
 503 
 504   // Final check of all ranges after ergonomics which may change values.
 505   if (!JVMFlagLimit::check_all_ranges()) {
 506     return JNI_EINVAL;
 507   }
 508 
 509   // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
 510   bool constraint_result = JVMFlagLimit::check_all_constraints(JVMFlagConstraintPhase::AfterErgo);
 511   if (!constraint_result) {
 512     return JNI_EINVAL;
 513   }
 514 
 515   if (PauseAtStartup) {
 516     os::pause();
 517   }
 518 
 519   HOTSPOT_VM_INIT_BEGIN();
 520 
 521   // Timing (must come after argument parsing)
 522   TraceTime timer("Create VM", TRACETIME_LOG(Info, startuptime));
 523 
 524   // Initialize the os module after parsing the args
 525   jint os_init_2_result = os::init_2();
 526   if (os_init_2_result != JNI_OK) return os_init_2_result;
 527 
 528 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT
 529   // Initialize assert poison page mechanism.
 530   if (ShowRegistersOnAssert) {
 531     initialize_assert_poison();
 532   }
 533 #endif // CAN_SHOW_REGISTERS_ON_ASSERT
 534 
 535   SafepointMechanism::initialize();
 536 
 537   jint adjust_after_os_result = Arguments::adjust_after_os();
 538   if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
 539 
 540   // Initialize output stream logging
 541   ostream_init_log();
 542 
 543   // Launch -agentlib/-agentpath and converted -Xrun agents
 544   JvmtiAgentList::load_agents();
 545 
 546   // Initialize Threads state
 547   _number_of_threads = 0;
 548   _number_of_non_daemon_threads = 0;
 549 
 550   // Initialize global data structures and create system classes in heap
 551   vm_init_globals();
 552 
 553 #if INCLUDE_JVMCI
 554   if (JVMCICounterSize > 0) {
 555     JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtJVMCI);
 556     memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize);
 557   } else {
 558     JavaThread::_jvmci_old_thread_counters = nullptr;
 559   }
 560 #endif // INCLUDE_JVMCI
 561 
 562   // Initialize OopStorage for threadObj
 563   JavaThread::_thread_oop_storage = OopStorageSet::create_strong("Thread OopStorage", mtThread);
 564 
 565   // Attach the main thread to this os thread
 566   JavaThread* main_thread = new JavaThread();
 567   main_thread->set_thread_state(_thread_in_vm);
 568   main_thread->initialize_thread_current();
 569   // Once mutexes and main_thread are ready, we can use NmtVirtualMemoryLocker.
 570   MemTracker::NmtVirtualMemoryLocker::set_safe_to_use();
 571   // must do this before set_active_handles
 572   main_thread->record_stack_base_and_size();
 573   main_thread->register_thread_stack_with_NMT();
 574   main_thread->set_active_handles(JNIHandleBlock::allocate_block());
 575   MACOS_AARCH64_ONLY(main_thread->init_wx());
 576 
 577   // Set the _monitor_owner_id now since we will run Java code before the Thread instance
 578   // is even created. The same value will be assigned to the Thread instance on init.
 579   main_thread->set_monitor_owner_id(ThreadIdentifier::next());
 580 
 581   if (!Thread::set_as_starting_thread(main_thread)) {
 582     vm_shutdown_during_initialization(
 583                                       "Failed necessary internal allocation. Out of swap space");
 584     main_thread->smr_delete();
 585     *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
 586     return JNI_ENOMEM;
 587   }
 588 
 589   JFR_ONLY(Jfr::initialize_main_thread(main_thread);)
 590 
 591   // Enable guard page *after* os::create_main_thread(), otherwise it would
 592   // crash Linux VM, see notes in os_linux.cpp.
 593   main_thread->stack_overflow_state()->create_stack_guard_pages();
 594 
 595   // Initialize Java-Level synchronization subsystem
 596   ObjectMonitor::Initialize();
 597   ObjectSynchronizer::initialize();
 598 
 599   // Initialize global modules
 600   jint status = init_globals();
 601   if (status != JNI_OK) {
 602     main_thread->smr_delete();
 603     *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
 604     return status;
 605   }
 606 
 607   // Have the WatcherThread read the release file in the background.
 608   ReadReleaseFileTask* read_task = new ReadReleaseFileTask();
 609   read_task->enroll();
 610 
 611   // Create WatcherThread as soon as we can since we need it in case
 612   // of hangs during error reporting.
 613   WatcherThread::start();
 614 
 615   // Add main_thread to threads list to finish barrier setup with
 616   // on_thread_attach.  Should be before starting to build Java objects in
 617   // init_globals2, which invokes barriers.
 618   {
 619     MutexLocker mu(Threads_lock);
 620     Threads::add(main_thread);
 621   }
 622 
 623   status = init_globals2();
 624   if (status != JNI_OK) {
 625     Threads::remove(main_thread, false);
 626     // It is possible that we managed to fully initialize Universe but have then
 627     // failed by throwing an exception. In that case our caller JNI_CreateJavaVM
 628     // will want to report it, so we can't delete the main thread.
 629     if (!main_thread->has_pending_exception()) {
 630       main_thread->smr_delete();
 631     }
 632     *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
 633     return status;
 634   }
 635 
 636   ObjectMonitor::Initialize2();
 637 
 638   JFR_ONLY(Jfr::on_create_vm_1();)
 639 
 640   // Should be done after the heap is fully created
 641   main_thread->cache_global_variables();
 642 
 643   // Any JVMTI raw monitors entered in onload will transition into
 644   // real raw monitor. VM is setup enough here for raw monitor enter.
 645   JvmtiExport::transition_pending_onload_raw_monitors();
 646 
 647   // Create the VMThread
 648   { TraceTime timer("Start VMThread", TRACETIME_LOG(Info, startuptime));
 649 
 650     VMThread::create();
 651     VMThread* vmthread = VMThread::vm_thread();
 652 
 653     if (!os::create_thread(vmthread, os::vm_thread)) {
 654       vm_exit_during_initialization("Cannot create VM thread. "
 655                                     "Out of system resources.");
 656     }
 657 
 658     // Wait for the VM thread to become ready, and VMThread::run to initialize
 659     // Monitors can have spurious returns, must always check another state flag
 660     {
 661       MonitorLocker ml(Notify_lock);
 662       os::start_thread(vmthread);
 663       while (!vmthread->is_running()) {
 664         ml.wait();
 665       }
 666     }
 667   }
 668 
 669   assert(Universe::is_fully_initialized(), "not initialized");
 670   if (VerifyDuringStartup) {
 671     // Make sure we're starting with a clean slate.
 672     VM_Verify verify_op;
 673     VMThread::execute(&verify_op);
 674   }
 675 
 676   // We need this to update the java.vm.info property in case any flags used
 677   // to initially define it have been changed. This is needed for both CDS
 678   // since UseSharedSpaces may be changed after java.vm.info
 679   // is initially computed. See Abstract_VM_Version::vm_info_string().
 680   // This update must happen before we initialize the java classes, but
 681   // after any initialization logic that might modify the flags.
 682   Arguments::update_vm_info_property(VM_Version::vm_info_string());
 683 
 684   JavaThread* THREAD = JavaThread::current(); // For exception macros.
 685   HandleMark hm(THREAD);
 686 
 687   // Always call even when there are not JVMTI environments yet, since environments
 688   // may be attached late and JVMTI must track phases of VM execution
 689   JvmtiExport::enter_early_start_phase();
 690 
 691   // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
 692   JvmtiExport::post_early_vm_start();
 693 
 694   // Launch -Xrun agents early if EagerXrunInit is set
 695   if (EagerXrunInit) {
 696     JvmtiAgentList::load_xrun_agents();
 697   }
 698 
 699   initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
 700 
 701   quicken_jni_functions();
 702 
 703   // No more stub generation allowed after that point.
 704   StubCodeDesc::freeze();
 705 
 706 #ifdef ADDRESS_SANITIZER
 707   Asan::initialize();
 708 #endif
 709 
 710   // Set flag that basic initialization has completed. Used by exceptions and various
 711   // debug stuff, that does not work until all basic classes have been initialized.
 712   set_init_completed();
 713 
 714   LogConfiguration::post_initialize();
 715   Metaspace::post_initialize();
 716   MutexLockerImpl::post_initialize();
 717 
 718   HOTSPOT_VM_INIT_END();
 719 
 720   // record VM initialization completion time
 721 #if INCLUDE_MANAGEMENT
 722   Management::record_vm_init_completed();
 723 #endif // INCLUDE_MANAGEMENT
 724 
 725   log_info(os)("Initialized VM with process ID %d", os::current_process_id());
 726 
 727   if (!FLAG_IS_DEFAULT(CreateCoredumpOnCrash) && CreateCoredumpOnCrash) {
 728     char buffer[2*JVM_MAXPATHLEN];
 729     os::check_core_dump_prerequisites(buffer, sizeof(buffer), true);
 730   }
 731 
 732   // Signal Dispatcher needs to be started before VMInit event is posted
 733   os::initialize_jdk_signal_support(CHECK_JNI_ERR);
 734 
 735   // Start Attach Listener if +StartAttachListener or it can't be started lazily
 736   if (!DisableAttachMechanism) {
 737     AttachListener::vm_start();
 738     if (StartAttachListener || AttachListener::init_at_startup()) {
 739       AttachListener::init();
 740     }
 741   }
 742 
 743   // Launch -Xrun agents if EagerXrunInit is not set.
 744   if (!EagerXrunInit) {
 745     JvmtiAgentList::load_xrun_agents();
 746   }
 747 
 748   Arena::start_chunk_pool_cleaner_task();
 749 
 750   // Start the service thread
 751   // The service thread enqueues JVMTI deferred events and does various hashtable
 752   // and other cleanups.  Needs to start before the compilers start posting events.
 753   ServiceThread::initialize();
 754 
 755   if (CDSConfig::is_using_aot_linked_classes()) {
 756     nmethod::post_delayed_compiled_method_load_events();
 757   }
 758 
 759   // Start the monitor deflation thread:
 760   MonitorDeflationThread::initialize();
 761 
 762   // initialize compiler(s)
 763 #if defined(COMPILER1) || COMPILER2_OR_JVMCI
 764   bool init_compilation = true;
 765 #if INCLUDE_JVMCI
 766   bool force_JVMCI_initialization = false;
 767   if (EnableJVMCI) {
 768     // Initialize JVMCI eagerly when it is explicitly requested.
 769     // Or when JVMCILibDumpJNIConfig or JVMCIPrintProperties is enabled.
 770     force_JVMCI_initialization = EagerJVMCI || JVMCIPrintProperties || JVMCILibDumpJNIConfig;
 771     if (!force_JVMCI_initialization && UseJVMCICompiler && !UseJVMCINativeLibrary && (!UseInterpreter || !BackgroundCompilation)) {
 772       // Force initialization of jarjvmci otherwise requests for blocking
 773       // compilations will not actually block until jarjvmci is initialized.
 774       force_JVMCI_initialization = true;
 775     }
 776     if (JVMCIPrintProperties || JVMCILibDumpJNIConfig) {
 777       // Both JVMCILibDumpJNIConfig and JVMCIPrintProperties exit the VM
 778       // so compilation should be disabled. This prevents dumping or
 779       // printing from happening more than once.
 780       init_compilation = false;
 781     }
 782   }
 783 #endif
 784   if (init_compilation) {
 785     CompileBroker::compilation_init(CHECK_JNI_ERR);
 786   }
 787 #endif
 788 
 789   if (CDSConfig::is_using_aot_linked_classes()) {
 790     SystemDictionary::restore_archived_method_handle_intrinsics();
 791     AOTLinkedClassBulkLoader::init_javabase_classes(THREAD);
 792   }
 793 
 794   // Start string deduplication thread if requested.
 795   if (StringDedup::is_enabled()) {
 796     StringDedup::start();
 797   }
 798 
 799   // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
 800   // It is done after compilers are initialized, because otherwise compilations of
 801   // signature polymorphic MH intrinsics can be missed
 802   // (see SystemDictionary::find_method_handle_intrinsic).
 803   initialize_jsr292_core_classes(CHECK_JNI_ERR);
 804 
 805   // This will initialize the module system.  Only java.base classes can be
 806   // loaded until phase 2 completes
 807   call_initPhase2(CHECK_JNI_ERR);
 808 
 809   if (CDSConfig::is_using_aot_linked_classes()) {
 810     AOTLinkedClassBulkLoader::init_non_javabase_classes(THREAD);
 811   }
 812 #ifndef PRODUCT
 813   HeapShared::initialize_test_class_from_archive(THREAD);
 814 #endif
 815 
 816   JFR_ONLY(Jfr::on_create_vm_2();)
 817 
 818   // Always call even when there are not JVMTI environments yet, since environments
 819   // may be attached late and JVMTI must track phases of VM execution
 820   JvmtiExport::enter_start_phase();
 821 
 822   // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
 823   JvmtiExport::post_vm_start();
 824 
 825   // Final system initialization including security manager and system class loader
 826   call_initPhase3(CHECK_JNI_ERR);
 827 
 828   // cache the system and platform class loaders
 829   SystemDictionary::compute_java_loaders(CHECK_JNI_ERR);
 830 
 831   // Initiate replay training processing once preloading is over.
 832   CompileBroker::init_training_replay();
 833 
 834   AOTLinkedClassBulkLoader::replay_training_at_init_for_preloaded_classes(CHECK_JNI_ERR);
 835 
 836   if (Continuations::enabled()) {
 837     // Initialize Continuation class now so that failure to create enterSpecial/doYield
 838     // special nmethods due to limited CodeCache size can be treated as a fatal error at
 839     // startup with the proper message that CodeCache size is too small.
 840     initialize_class(vmSymbols::jdk_internal_vm_Continuation(), CHECK_JNI_ERR);
 841   }
 842 
 843   if (NativeHeapTrimmer::enabled()) {
 844     NativeHeapTrimmer::initialize();
 845   }
 846 
 847   // Always call even when there are not JVMTI environments yet, since environments
 848   // may be attached late and JVMTI must track phases of VM execution
 849   JvmtiExport::enter_live_phase();
 850 
 851   // Make perfmemory accessible
 852   PerfMemory::set_accessible(true);
 853 
 854   // Notify JVMTI agents that VM initialization is complete - nop if no agents.
 855   JvmtiExport::post_vm_initialized();
 856 
 857 #if INCLUDE_JVMCI
 858   if (force_JVMCI_initialization) {
 859     JVMCI::initialize_compiler_in_create_vm(CHECK_JNI_ERR);
 860   }
 861 #endif
 862 
 863   JFR_ONLY(Jfr::on_create_vm_3();)
 864 
 865 #if INCLUDE_MANAGEMENT
 866   bool start_agent = true;
 867 #if INCLUDE_CDS
 868   start_agent = !CDSConfig::is_dumping_final_static_archive();
 869   if (!start_agent) {
 870     log_info(aot)("Not starting management agent during creation of AOT cache.");
 871   }
 872 #endif // INCLUDE_CDS
 873   if (start_agent) {
 874     Management::initialize(THREAD);
 875 
 876     if (HAS_PENDING_EXCEPTION) {
 877       // management agent fails to start possibly due to
 878       // configuration problem and is responsible for printing
 879       // stack trace if appropriate. Simply exit VM.
 880       vm_exit(1);
 881     }
 882   }
 883 #endif // INCLUDE_MANAGEMENT
 884 
 885   if (UsePerfData)         PerfDataManager::create_misc_perfdata();
 886   if (CheckJNICalls)                  JniPeriodicChecker::engage();
 887 
 888   call_postVMInitHook(THREAD);
 889   // The Java side of PostVMInitHook.run must deal with all
 890   // exceptions and provide means of diagnosis.
 891   if (HAS_PENDING_EXCEPTION) {
 892     CLEAR_PENDING_EXCEPTION;
 893   }
 894 
 895   // Let WatcherThread run all registered periodic tasks now.
 896   // NOTE:  All PeriodicTasks should be registered by now. If they
 897   //   aren't, late joiners might appear to start slowly (we might
 898   //   take a while to process their first tick).
 899   WatcherThread::run_all_tasks();
 900 
 901   create_vm_timer.end();
 902 #ifdef ASSERT
 903   _vm_complete = true;
 904 #endif
 905 
 906   if (CDSConfig::is_dumping_classic_static_archive()) {
 907     // Classic -Xshare:dump, aka "old workflow"
 908     AOTMetaspace::dump_static_archive(CHECK_JNI_ERR);
 909   } else if (CDSConfig::is_dumping_final_static_archive()) {
 910     tty->print_cr("Reading AOTConfiguration %s and writing AOTCache %s", AOTConfiguration, AOTCache);
 911     AOTMetaspace::dump_static_archive(CHECK_JNI_ERR);
 912   }
 913 
 914   if (log_is_enabled(Info, perf, class, link)) {
 915     LogStreamHandle(Info, perf, class, link) log;
 916     log.print_cr("At VM initialization completion:");
 917     ClassLoader::print_counters(&log);
 918   }
 919 
 920   return JNI_OK;
 921 }
 922 
 923 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
 924 // the program falls off the end of main(). Another VM exit path is through
 925 // vm_exit(), when the program calls System.exit() to return a value, or when
 926 // there is a serious error in VM.
 927 // These two separate shutdown paths are not exactly the same, but they share
 928 // Shutdown.shutdown() at Java level and before_exit() and VM_Exit op at VM level.
 929 //
 930 // Shutdown sequence:
 931 //   + Shutdown native memory tracking if it is on
 932 //   + Wait until we are the last non-daemon thread to execute
 933 //     <-- every thing is still working at this moment -->
 934 //   + Call java.lang.Shutdown.shutdown(), which will invoke Java level
 935 //        shutdown hooks
 936 //   + Call before_exit(), prepare for VM exit
 937 //      > run VM level shutdown hooks (they are registered through JVM_OnExit(),
 938 //        currently the only user of this mechanism is File.deleteOnExit())
 939 //      > stop watcher thread,
 940 //        post thread end and vm death events to JVMTI,
 941 //        stop signal thread
 942 //   + Call JavaThread::exit(), it will:
 943 //      > release JNI handle blocks, remove stack guard pages
 944 //      > remove this thread from Threads list
 945 //     <-- no more Java code from this thread after this point -->
 946 //   + Stop VM thread, it will bring the remaining VM to a safepoint and stop
 947 //     the compiler threads at safepoint
 948 //     <-- do not use anything that could get blocked by Safepoint -->
 949 //   + Disable tracing at JNI/JVM barriers
 950 //   + Set _vm_exited flag for threads that are still running native code
 951 //   + Call exit_globals()
 952 //      > deletes tty
 953 //      > deletes PerfMemory resources
 954 //   + Delete this thread
 955 //   + Return to caller
 956 
 957 void Threads::destroy_vm() {
 958   JavaThread* thread = JavaThread::current();
 959 
 960 #ifdef ASSERT
 961   _vm_complete = false;
 962 #endif
 963   // Wait until we are the last non-daemon thread to execute, or
 964   // if we are a daemon then wait until the last non-daemon thread has
 965   // executed.
 966   bool daemon = java_lang_Thread::is_daemon(thread->threadObj());
 967   int expected = daemon ? 0 : 1;
 968   {
 969     MonitorLocker nu(Threads_lock);
 970     while (Threads::number_of_non_daemon_threads() > expected)
 971       // This wait should make safepoint checks, wait without a timeout.
 972       nu.wait(0);
 973   }
 974 
 975   EventShutdown e;
 976   if (e.should_commit()) {
 977     e.set_reason("No remaining non-daemon Java threads");
 978     e.commit();
 979   }
 980 
 981   // Hang forever on exit if we are reporting an error.
 982   if (ShowMessageBoxOnError && VMError::is_error_reported()) {
 983     os::infinite_sleep();
 984   }
 985   os::wait_for_keypress_at_exit();
 986 
 987   // run Java level shutdown hooks
 988   thread->invoke_shutdown_hooks();
 989 
 990   before_exit(thread);
 991 
 992   thread->exit(true);
 993 
 994   // We are no longer on the main thread list but could still be in a
 995   // secondary list where another thread may try to interact with us.
 996   // So wait until all such interactions are complete before we bring
 997   // the VM to the termination safepoint. Normally this would be done
 998   // using thread->smr_delete() below where we delete the thread, but
 999   // we can't call that after the termination safepoint is active as
1000   // we will deadlock on the Threads_lock. Once all interactions are
1001   // complete it is safe to directly delete the thread at any time.
1002   ThreadsSMRSupport::wait_until_not_protected(thread);
1003 
1004   // Stop VM thread.
1005   {
1006     // 4945125 The vm thread comes to a safepoint during exit.
1007     // GC vm_operations can get caught at the safepoint, and the
1008     // heap is unparseable if they are caught. Grab the Heap_lock
1009     // to prevent this. The GC vm_operations will not be able to
1010     // queue until after the vm thread is dead. After this point,
1011     // we'll never emerge out of the safepoint before the VM exits.
1012     // Assert that the thread is terminated so that acquiring the
1013     // Heap_lock doesn't cause the terminated thread to participate in
1014     // the safepoint protocol.
1015 
1016     assert(thread->is_terminated(), "must be terminated here");
1017     MutexLocker ml(Heap_lock);
1018 
1019     VMThread::wait_for_vm_thread_exit();
1020     assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
1021     VMThread::destroy();
1022   }
1023 
1024   // Now, all Java threads are gone except daemon threads. Daemon threads
1025   // running Java code or in VM are stopped by the Safepoint. However,
1026   // daemon threads executing native code are still running.  But they
1027   // will be stopped at native=>Java/VM barriers. Note that we can't
1028   // simply kill or suspend them, as it is inherently deadlock-prone.
1029 
1030   VM_Exit::set_vm_exited();
1031 
1032   // Clean up ideal graph printers after the VMThread has started
1033   // the final safepoint which will block all the Compiler threads.
1034   // Note that this Thread has already logically exited so the
1035   // clean_up() function's use of a JavaThreadIteratorWithHandle
1036   // would be a problem except set_vm_exited() has remembered the
1037   // shutdown thread which is granted a policy exception.
1038 #if defined(COMPILER2) && !defined(PRODUCT)
1039   IdealGraphPrinter::clean_up();
1040 #endif
1041 
1042   notify_vm_shutdown();
1043 
1044   // exit_globals() will delete tty
1045   exit_globals();
1046 
1047   // Deleting the shutdown thread here is safe. See comment on
1048   // wait_until_not_protected() above.
1049   delete thread;
1050 
1051 #if INCLUDE_JVMCI
1052   if (JVMCICounterSize > 0) {
1053     FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters);
1054   }
1055 #endif
1056 
1057   LogConfiguration::finalize();
1058 }
1059 
1060 
1061 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
1062   if (version == JNI_VERSION_1_1) return JNI_TRUE;
1063   return is_supported_jni_version(version);
1064 }
1065 
1066 
1067 jboolean Threads::is_supported_jni_version(jint version) {
1068   if (version == JNI_VERSION_1_2) return JNI_TRUE;
1069   if (version == JNI_VERSION_1_4) return JNI_TRUE;
1070   if (version == JNI_VERSION_1_6) return JNI_TRUE;
1071   if (version == JNI_VERSION_1_8) return JNI_TRUE;
1072   if (version == JNI_VERSION_9) return JNI_TRUE;
1073   if (version == JNI_VERSION_10) return JNI_TRUE;
1074   if (version == JNI_VERSION_19) return JNI_TRUE;
1075   if (version == JNI_VERSION_20) return JNI_TRUE;
1076   if (version == JNI_VERSION_21) return JNI_TRUE;
1077   if (version == JNI_VERSION_24) return JNI_TRUE;
1078   return JNI_FALSE;
1079 }
1080 
1081 void Threads::add(JavaThread* p, bool force_daemon) {
1082   // The threads lock must be owned at this point
1083   assert(Threads_lock->owned_by_self(), "must have threads lock");
1084   assert(p->monitor_owner_id() != 0, "should be set");
1085 
1086   BarrierSet::barrier_set()->on_thread_attach(p);
1087 
1088   // Once a JavaThread is added to the Threads list, smr_delete() has
1089   // to be used to delete it. Otherwise we can just delete it directly.
1090   p->set_on_thread_list();
1091 
1092   _number_of_threads++;
1093   oop threadObj = p->threadObj();
1094   bool daemon = true;
1095   // Bootstrapping problem: threadObj can be null for initial
1096   // JavaThread (or for threads attached via JNI)
1097   if (!force_daemon &&
1098       (threadObj == nullptr || !java_lang_Thread::is_daemon(threadObj))) {
1099     _number_of_non_daemon_threads++;
1100     daemon = false;
1101   }
1102 
1103   ThreadService::add_thread(p, daemon);
1104 
1105   // Maintain fast thread list
1106   ThreadsSMRSupport::add_thread(p);
1107 
1108   // Increase the ObjectMonitor ceiling for the new thread.
1109   ObjectSynchronizer::inc_in_use_list_ceiling();
1110 
1111   // Possible GC point.
1112   Events::log(Thread::current(), "Thread added: " INTPTR_FORMAT, p2i(p));
1113 
1114   // Make new thread known to active EscapeBarrier
1115   EscapeBarrier::thread_added(p);
1116 }
1117 
1118 void Threads::remove(JavaThread* p, bool is_daemon) {
1119   // Extra scope needed for Thread_lock, so we can check
1120   // that we do not remove thread without safepoint code notice
1121   {
1122     ConditionalMutexLocker throttle_ml(ThreadsLockThrottle_lock, UseThreadsLockThrottleLock);
1123     MonitorLocker ml(Threads_lock);
1124 
1125     if (ThreadIdTable::is_initialized()) {
1126       // This cleanup must be done before the current thread's GC barrier
1127       // is detached since we need to touch the threadObj oop.
1128       jlong tid = SharedRuntime::get_java_tid(p);
1129       ThreadIdTable::remove_thread(tid);
1130     }
1131 
1132     // BarrierSet state must be destroyed after the last thread transition
1133     // before the thread terminates. Thread transitions result in calls to
1134     // StackWatermarkSet::on_safepoint(), which performs GC processing,
1135     // requiring the GC state to be alive.
1136     BarrierSet::barrier_set()->on_thread_detach(p);
1137     if (p->is_exiting()) {
1138       // If we got here via JavaThread::exit(), then we remember that the
1139       // thread's GC barrier has been detached. We don't do this when we get
1140       // here from another path, e.g., cleanup_failed_attach_current_thread().
1141       p->set_terminated(JavaThread::_thread_gc_barrier_detached);
1142     }
1143 
1144     assert(ThreadsSMRSupport::get_java_thread_list()->includes(p), "p must be present");
1145 
1146     // Maintain fast thread list
1147     ThreadsSMRSupport::remove_thread(p);
1148 
1149     _number_of_threads--;
1150     if (!is_daemon) {
1151       _number_of_non_daemon_threads--;
1152 
1153       // If this is the last non-daemon thread then we need to do
1154       // a notify on the Threads_lock so a thread waiting
1155       // on destroy_vm will wake up. But that thread could be a daemon
1156       // or non-daemon, so we notify for both the 0 and 1 case.
1157       if (number_of_non_daemon_threads() <= 1) {
1158         ml.notify_all();
1159       }
1160     }
1161     ThreadService::remove_thread(p, is_daemon);
1162 
1163     // Make sure that safepoint code disregard this thread. This is needed since
1164     // the thread might mess around with locks after this point. This can cause it
1165     // to do callbacks into the safepoint code. However, the safepoint code is not aware
1166     // of this thread since it is removed from the queue.
1167     p->set_terminated(JavaThread::_thread_terminated);
1168 
1169     // Notify threads waiting in EscapeBarriers
1170     EscapeBarrier::thread_removed(p);
1171   } // unlock Threads_lock and ThreadsLockThrottle_lock
1172 
1173   // Reduce the ObjectMonitor ceiling for the exiting thread.
1174   ObjectSynchronizer::dec_in_use_list_ceiling();
1175 
1176   // Since Events::log uses a lock, we grab it outside the Threads_lock
1177   Events::log(Thread::current(), "Thread exited: " INTPTR_FORMAT, p2i(p));
1178 }
1179 
1180 // Operations on the Threads list for GC.  These are not explicitly locked,
1181 // but the garbage collector must provide a safe context for them to run.
1182 // In particular, these things should never be called when the Threads_lock
1183 // is held by some other thread. (Note: the Safepoint abstraction also
1184 // uses the Threads_lock to guarantee this property. It also makes sure that
1185 // all threads gets blocked when exiting or starting).
1186 
1187 void Threads::oops_do(OopClosure* f, NMethodClosure* cf) {
1188   ALL_JAVA_THREADS(p) {
1189     p->oops_do(f, cf);
1190   }
1191   VMThread::vm_thread()->oops_do(f, cf);
1192 }
1193 
1194 void Threads::change_thread_claim_token() {
1195   if (++_thread_claim_token == 0) {
1196     // On overflow of the token counter, there is a risk of future
1197     // collisions between a new global token value and a stale token
1198     // for a thread, because not all iterations visit all threads.
1199     // (Though it's pretty much a theoretical concern for non-trivial
1200     // token counter sizes.)  To deal with the possibility, reset all
1201     // the thread tokens to zero on global token overflow.
1202     struct ResetClaims : public ThreadClosure {
1203       virtual void do_thread(Thread* t) {
1204         t->claim_threads_do(false, 0);
1205       }
1206     } reset_claims;
1207     Threads::threads_do(&reset_claims);
1208     // On overflow, update the global token to non-zero, to
1209     // avoid the special "never claimed" initial thread value.
1210     _thread_claim_token = 1;
1211   }
1212 }
1213 
1214 #ifdef ASSERT
1215 static void assert_thread_claimed(const char* kind, Thread* t, uintx expected) {
1216   const uintx token = t->threads_do_token();
1217   assert(token == expected,
1218          "%s " PTR_FORMAT " has incorrect value %zu != %zu",
1219          kind, p2i(t), token, expected);
1220 }
1221 
1222 void Threads::assert_all_threads_claimed() {
1223   ALL_JAVA_THREADS(p) {
1224     assert_thread_claimed("JavaThread", p, _thread_claim_token);
1225   }
1226 
1227   struct NJTClaimedVerifierClosure : public ThreadClosure {
1228     uintx _thread_claim_token;
1229 
1230     NJTClaimedVerifierClosure(uintx thread_claim_token) : ThreadClosure(), _thread_claim_token(thread_claim_token) { }
1231 
1232     virtual void do_thread(Thread* thread) override {
1233       assert_thread_claimed("Non-JavaThread", VMThread::vm_thread(), _thread_claim_token);
1234     }
1235   } tc(_thread_claim_token);
1236 
1237   non_java_threads_do(&tc);
1238 }
1239 #endif // ASSERT
1240 
1241 class ParallelOopsDoThreadClosure : public ThreadClosure {
1242 private:
1243   OopClosure* _f;
1244   NMethodClosure* _cf;
1245 public:
1246   ParallelOopsDoThreadClosure(OopClosure* f, NMethodClosure* cf) : _f(f), _cf(cf) {}
1247   void do_thread(Thread* t) {
1248     t->oops_do(_f, _cf);
1249   }
1250 };
1251 
1252 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, NMethodClosure* cf) {
1253   ParallelOopsDoThreadClosure tc(f, cf);
1254   possibly_parallel_threads_do(is_par, &tc);
1255 }
1256 
1257 void Threads::metadata_do(MetadataClosure* f) {
1258   ALL_JAVA_THREADS(p) {
1259     p->metadata_do(f);
1260   }
1261 }
1262 
1263 class ThreadHandlesClosure : public ThreadClosure {
1264   void (*_f)(Metadata*);
1265  public:
1266   ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
1267   virtual void do_thread(Thread* thread) {
1268     thread->metadata_handles_do(_f);
1269   }
1270 };
1271 
1272 void Threads::metadata_handles_do(void f(Metadata*)) {
1273   // Only walk the Handles in Thread.
1274   ThreadHandlesClosure handles_closure(f);
1275   threads_do(&handles_closure);
1276 }
1277 
1278 #if INCLUDE_JVMTI
1279 // Get Java threads that are waiting to enter or re-enter the specified monitor.
1280 // Java threads that are executing mounted virtual threads are not included.
1281 GrowableArray<JavaThread*>* Threads::get_pending_threads(ThreadsList * t_list,
1282                                                          int count,
1283                                                          address monitor) {
1284   assert(Thread::current()->is_VM_thread(), "Must be the VM thread");
1285   GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
1286 
1287   int i = 0;
1288   for (JavaThread* p : *t_list) {
1289     if (!p->can_call_java()) continue;
1290 
1291     oop thread_oop = JvmtiEnvBase::get_vthread_or_thread_oop(p);
1292     if (thread_oop->is_a(vmClasses::BaseVirtualThread_klass())) {
1293       continue;
1294     }
1295     // The first stage of async deflation does not affect any field
1296     // used by this comparison so the ObjectMonitor* is usable here.
1297     address pending = (address)p->current_pending_monitor();
1298     address waiting = (address)p->current_waiting_monitor();
1299     // do not include virtual threads to the list
1300     jint state = JvmtiEnvBase::get_thread_state(thread_oop, p);
1301     if (pending == monitor || (waiting == monitor &&
1302         (state & JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER))
1303     ) { // found a match
1304       if (i < count) result->append(p);   // save the first count matches
1305       i++;
1306     }
1307   }
1308 
1309   return result;
1310 }
1311 #endif // INCLUDE_JVMTI
1312 
1313 JavaThread* Threads::owning_thread_from_object(ThreadsList * t_list, oop obj) {
1314   for (JavaThread* q : *t_list) {
1315     // Need to start processing before accessing oops in the thread.
1316     StackWatermark* watermark = StackWatermarkSet::get(q, StackWatermarkKind::gc);
1317     if (watermark != nullptr) {
1318       watermark->start_processing();
1319     }
1320 
1321     if (q->lock_stack().contains(obj)) {
1322       return q;
1323     }
1324   }
1325   return nullptr;
1326 }
1327 
1328 JavaThread* Threads::owning_thread_from_monitor(ThreadsList* t_list, ObjectMonitor* monitor) {
1329   if (monitor->has_anonymous_owner()) {
1330     return owning_thread_from_object(t_list, monitor->object());
1331   } else {
1332     JavaThread* the_owner = nullptr;
1333     for (JavaThread* q : *t_list) {
1334       if (monitor->has_owner(q)) {
1335         the_owner = q;
1336         break;
1337       }
1338     }
1339     return the_owner;
1340   }
1341 }
1342 
1343 class PrintOnClosure : public ThreadClosure {
1344 private:
1345   outputStream* _st;
1346 
1347 public:
1348   PrintOnClosure(outputStream* st) :
1349       _st(st) {}
1350 
1351   virtual void do_thread(Thread* thread) {
1352     if (thread != nullptr) {
1353       thread->print_on(_st);
1354       _st->cr();
1355     }
1356   }
1357 };
1358 
1359 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
1360 void Threads::print_on(outputStream* st, bool print_stacks,
1361                        bool internal_format, bool print_concurrent_locks,
1362                        bool print_extended_info) {
1363   char buf[32];
1364   st->print_raw_cr(os::local_time_string(buf, sizeof(buf)));
1365 
1366   st->print_cr("Full thread dump %s (%s %s)",
1367                VM_Version::vm_name(),
1368                VM_Version::vm_release(),
1369                VM_Version::vm_info_string());
1370   JDK_Version::current().to_string(buf, sizeof(buf));
1371   const char* runtime_name = JDK_Version::runtime_name() != nullptr ?
1372                              JDK_Version::runtime_name() : "";
1373   const char* runtime_version = JDK_Version::runtime_version() != nullptr ?
1374                                 JDK_Version::runtime_version() : "";
1375   const char* vendor_version = JDK_Version::runtime_vendor_version() != nullptr ?
1376                                JDK_Version::runtime_vendor_version() : "";
1377   const char* jdk_debug_level = VM_Version::printable_jdk_debug_level() != nullptr ?
1378                                 VM_Version::printable_jdk_debug_level() : "";
1379 
1380   st->print_cr("                 JDK version: %s%s%s (%s) (%sbuild %s)", runtime_name,
1381                 (*vendor_version != '\0') ? " " : "", vendor_version,
1382                 buf, jdk_debug_level, runtime_version);
1383 
1384   st->cr();
1385 
1386 #if INCLUDE_SERVICES
1387   // Dump concurrent locks
1388   ConcurrentLocksDump concurrent_locks;
1389   if (print_concurrent_locks) {
1390     concurrent_locks.dump_at_safepoint();
1391   }
1392 #endif // INCLUDE_SERVICES
1393 
1394   ThreadsSMRSupport::print_info_on(st);
1395   st->cr();
1396 
1397   ALL_JAVA_THREADS(p) {
1398     ResourceMark rm;
1399     p->print_on(st, print_extended_info);
1400     if (print_stacks) {
1401       if (internal_format) {
1402         p->trace_stack();
1403       } else {
1404         p->print_stack_on(st);
1405         if (p->is_vthread_mounted()) {
1406           st->print_cr("   Mounted virtual thread #" INT64_FORMAT, java_lang_Thread::thread_id(p->vthread()));
1407           p->print_vthread_stack_on(st);
1408         }
1409       }
1410     }
1411     st->cr();
1412 #if INCLUDE_SERVICES
1413     if (print_concurrent_locks) {
1414       concurrent_locks.print_locks_on(p, st);
1415     }
1416 #endif // INCLUDE_SERVICES
1417   }
1418 
1419   PrintOnClosure cl(st);
1420   non_java_threads_do(&cl);
1421 
1422   st->flush();
1423 }
1424 
1425 void Threads::print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
1426                              int buflen, bool* found_current) {
1427   if (this_thread != nullptr) {
1428     bool is_current = (current == this_thread);
1429     *found_current = *found_current || is_current;
1430     st->print("%s", is_current ? "=>" : "  ");
1431 
1432     st->print(PTR_FORMAT, p2i(this_thread));
1433     st->print(" ");
1434     this_thread->print_on_error(st, buf, buflen);
1435     st->cr();
1436   }
1437 }
1438 
1439 class PrintOnErrorClosure : public ThreadClosure {
1440   outputStream* _st;
1441   Thread* _current;
1442   char* _buf;
1443   int _buflen;
1444   bool* _found_current;
1445   unsigned _num_printed;
1446  public:
1447   PrintOnErrorClosure(outputStream* st, Thread* current, char* buf,
1448                       int buflen, bool* found_current) :
1449    _st(st), _current(current), _buf(buf), _buflen(buflen), _found_current(found_current),
1450    _num_printed(0) {}
1451 
1452   virtual void do_thread(Thread* thread) {
1453     _num_printed++;
1454     Threads::print_on_error(thread, _st, _current, _buf, _buflen, _found_current);
1455   }
1456 
1457   unsigned num_printed() const { return _num_printed; }
1458 };
1459 
1460 // Threads::print_on_error() is called by fatal error handler. It's possible
1461 // that VM is not at safepoint and/or current thread is inside signal handler.
1462 // Don't print stack trace, as the stack may not be walkable. Don't allocate
1463 // memory (even in resource area), it might deadlock the error handler.
1464 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
1465                              int buflen) {
1466   ThreadsSMRSupport::print_info_on(st);
1467   st->cr();
1468 
1469   bool found_current = false;
1470   st->print_cr("Java Threads: ( => current thread )");
1471   unsigned num_java = 0;
1472   ALL_JAVA_THREADS(thread) {
1473     print_on_error(thread, st, current, buf, buflen, &found_current);
1474     num_java++;
1475   }
1476   st->print_cr("Total: %u", num_java);
1477   st->cr();
1478 
1479   st->print_cr("Other Threads:");
1480   unsigned num_other = ((VMThread::vm_thread() != nullptr) ? 1 : 0) +
1481       ((WatcherThread::watcher_thread() != nullptr) ? 1 : 0) +
1482       ((AsyncLogWriter::instance() != nullptr)  ? 1 : 0);
1483   print_on_error(VMThread::vm_thread(), st, current, buf, buflen, &found_current);
1484   print_on_error(WatcherThread::watcher_thread(), st, current, buf, buflen, &found_current);
1485   print_on_error(AsyncLogWriter::instance(), st, current, buf, buflen, &found_current);
1486 
1487   if (Universe::heap() != nullptr) {
1488     PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current);
1489     Universe::heap()->gc_threads_do(&print_closure);
1490     num_other += print_closure.num_printed();
1491   }
1492 
1493   if (!found_current) {
1494     st->cr();
1495     st->print("=>" PTR_FORMAT " (exited) ", p2i(current));
1496     current->print_on_error(st, buf, buflen);
1497     num_other++;
1498     st->cr();
1499   }
1500   st->print_cr("Total: %u", num_other);
1501   st->cr();
1502 
1503   st->print_cr("Threads with active compile tasks:");
1504   unsigned num = print_threads_compiling(st, buf, buflen);
1505   st->print_cr("Total: %u", num);
1506 }
1507 
1508 unsigned Threads::print_threads_compiling(outputStream* st, char* buf, int buflen, bool short_form) {
1509   unsigned num = 0;
1510   ALL_JAVA_THREADS(thread) {
1511     if (thread->is_Compiler_thread()) {
1512       CompilerThread* ct = (CompilerThread*) thread;
1513 
1514       // Keep task in local variable for null check.
1515       // ct->_task might be set to null by concurring compiler thread
1516       // because it completed the compilation. The task is never freed,
1517       // though, just returned to a free list.
1518       CompileTask* task = ct->task();
1519       if (task != nullptr) {
1520         thread->print_name_on_error(st, buf, buflen);
1521         st->print("  ");
1522         task->print(st, nullptr, short_form, true);
1523         num++;
1524       }
1525     }
1526   }
1527   return num;
1528 }
1529 
1530 void Threads::verify() {
1531   ALL_JAVA_THREADS(p) {
1532     p->verify();
1533   }
1534   VMThread* thread = VMThread::vm_thread();
1535   if (thread != nullptr) thread->verify();
1536 }