1 /*
2 * Copyright (c) 1997, 2024, Oracle and/or its affiliates. All rights reserved.
3 * Copyright (c) 2021, Azul Systems, Inc. All rights reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 #include "precompiled.hpp"
27 #include "cds/aotLinkedClassBulkLoader.hpp"
28 #include "cds/cds_globals.hpp"
29 #include "cds/cdsConfig.hpp"
30 #include "cds/heapShared.hpp"
31 #include "cds/metaspaceShared.hpp"
32 #include "cds/methodProfiler.hpp"
33 #include "classfile/classLoader.hpp"
34 #include "classfile/javaClasses.hpp"
35 #include "classfile/javaThreadStatus.hpp"
36 #include "classfile/systemDictionary.hpp"
37 #include "classfile/systemDictionaryShared.hpp"
38 #include "classfile/vmClasses.hpp"
39 #include "classfile/vmSymbols.hpp"
40 #include "code/SCCache.hpp"
41 #include "compiler/compilationPolicy.hpp"
42 #include "compiler/compileBroker.hpp"
43 #include "compiler/compileTask.hpp"
44 #include "compiler/compilerThread.hpp"
45 #include "compiler/precompiler.hpp"
46 #include "gc/shared/barrierSet.hpp"
47 #include "gc/shared/barrierSetNMethod.hpp"
48 #include "gc/shared/gcVMOperations.hpp"
49 #include "gc/shared/oopStorage.hpp"
50 #include "gc/shared/oopStorageSet.hpp"
51 #include "gc/shared/stringdedup/stringDedup.hpp"
52 #include "interpreter/interpreterRuntime.hpp"
53 #include "jfr/jfrEvents.hpp"
54 #include "jvm.h"
55 #include "jvmtifiles/jvmtiEnv.hpp"
56 #include "logging/log.hpp"
57 #include "logging/logAsyncWriter.hpp"
58 #include "logging/logConfiguration.hpp"
59 #include "memory/allocation.inline.hpp"
60 #include "memory/iterator.hpp"
61 #include "memory/oopFactory.hpp"
62 #include "memory/resourceArea.hpp"
63 #include "memory/universe.hpp"
64 #include "nmt/memTracker.hpp"
65 #include "oops/instanceKlass.hpp"
66 #include "oops/klass.inline.hpp"
67 #include "oops/oop.inline.hpp"
68 #include "oops/symbol.hpp"
69 #include "prims/jvm_misc.hpp"
70 #include "prims/jvmtiAgentList.hpp"
71 #include "prims/jvmtiEnvBase.hpp"
72 #include "runtime/arguments.hpp"
73 #include "runtime/fieldDescriptor.inline.hpp"
74 #include "runtime/flags/jvmFlagLimit.hpp"
75 #include "runtime/globals.hpp"
76 #include "runtime/handles.inline.hpp"
77 #include "runtime/interfaceSupport.inline.hpp"
78 #include "runtime/java.hpp"
79 #include "runtime/javaCalls.hpp"
80 #include "runtime/javaThread.inline.hpp"
81 #include "runtime/jniHandles.inline.hpp"
82 #include "runtime/jniPeriodicChecker.hpp"
83 #include "runtime/lockStack.inline.hpp"
84 #include "runtime/monitorDeflationThread.hpp"
85 #include "runtime/mutexLocker.hpp"
86 #include "runtime/nonJavaThread.hpp"
87 #include "runtime/objectMonitor.inline.hpp"
88 #include "runtime/osThread.hpp"
89 #include "runtime/safepoint.hpp"
90 #include "runtime/safepointMechanism.inline.hpp"
91 #include "runtime/safepointVerifiers.hpp"
92 #include "runtime/serviceThread.hpp"
93 #include "runtime/sharedRuntime.hpp"
94 #include "runtime/stackWatermarkSet.inline.hpp"
95 #include "runtime/statSampler.hpp"
96 #include "runtime/stubCodeGenerator.hpp"
97 #include "runtime/thread.inline.hpp"
98 #include "runtime/threadSMR.inline.hpp"
99 #include "runtime/threads.hpp"
100 #include "runtime/timer.hpp"
101 #include "runtime/timerTrace.hpp"
102 #include "runtime/trimNativeHeap.hpp"
103 #include "runtime/vmOperations.hpp"
104 #include "runtime/vm_version.hpp"
105 #include "services/attachListener.hpp"
106 #include "services/management.hpp"
107 #include "services/threadIdTable.hpp"
108 #include "services/threadService.hpp"
109 #include "utilities/dtrace.hpp"
110 #include "utilities/events.hpp"
111 #include "utilities/macros.hpp"
112 #include "utilities/vmError.hpp"
113 #if INCLUDE_JVMCI
114 #include "jvmci/jvmci.hpp"
115 #include "jvmci/jvmciEnv.hpp"
116 #endif
117 #ifdef COMPILER1
118 #include "c1/c1_Runtime1.hpp"
119 #endif
120 #ifdef COMPILER2
121 #include "opto/idealGraphPrinter.hpp"
122 #include "opto/runtime.hpp"
123 #endif
124 #if INCLUDE_JFR
125 #include "jfr/jfr.hpp"
126 #endif
127
128 // Initialization after module runtime initialization
129 void universe_post_module_init(); // must happen after call_initPhase2
130
131
132 static void initialize_class(Symbol* class_name, TRAPS) {
133 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
134 InstanceKlass::cast(klass)->initialize(CHECK);
135 }
136
137
138 // Creates the initial ThreadGroup
139 static Handle create_initial_thread_group(TRAPS) {
140 Handle system_instance = JavaCalls::construct_new_instance(
141 vmClasses::ThreadGroup_klass(),
142 vmSymbols::void_method_signature(),
143 CHECK_NH);
144 Universe::set_system_thread_group(system_instance());
145
146 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
147 Handle main_instance = JavaCalls::construct_new_instance(
148 vmClasses::ThreadGroup_klass(),
149 vmSymbols::threadgroup_string_void_signature(),
150 system_instance,
151 string,
152 CHECK_NH);
153 return main_instance;
154 }
155
156 // Creates the initial Thread, and sets it to running.
157 static void create_initial_thread(Handle thread_group, JavaThread* thread,
158 TRAPS) {
159 InstanceKlass* ik = vmClasses::Thread_klass();
160 assert(ik->is_initialized(), "must be");
161 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
162
163 // Cannot use JavaCalls::construct_new_instance because the java.lang.Thread
164 // constructor calls Thread.current(), which must be set here for the
165 // initial thread.
166 java_lang_Thread::set_thread(thread_oop(), thread);
167 thread->set_threadOopHandles(thread_oop());
168
169 Handle string = java_lang_String::create_from_str("main", CHECK);
170
171 JavaValue result(T_VOID);
172 JavaCalls::call_special(&result, thread_oop,
173 ik,
174 vmSymbols::object_initializer_name(),
175 vmSymbols::threadgroup_string_void_signature(),
176 thread_group,
177 string,
178 CHECK);
179
180 // Set thread status to running since main thread has
181 // been started and running.
182 java_lang_Thread::set_thread_status(thread_oop(),
183 JavaThreadStatus::RUNNABLE);
184 }
185
186 // Extract version and vendor specific information from
187 // java.lang.VersionProps fields.
188 // Returned char* is allocated in the thread's resource area
189 // so must be copied for permanency.
190 static const char* get_java_version_info(InstanceKlass* ik,
191 Symbol* field_name) {
192 fieldDescriptor fd;
193 bool found = ik != nullptr &&
194 ik->find_local_field(field_name,
195 vmSymbols::string_signature(), &fd);
196 if (found) {
197 oop name_oop = ik->java_mirror()->obj_field(fd.offset());
198 if (name_oop == nullptr) {
199 return nullptr;
200 }
201 const char* name = java_lang_String::as_utf8_string(name_oop);
202 return name;
203 } else {
204 return nullptr;
205 }
206 }
207
208 // ======= Threads ========
209
210 // The Threads class links together all active threads, and provides
211 // operations over all threads. It is protected by the Threads_lock,
212 // which is also used in other global contexts like safepointing.
213 // ThreadsListHandles are used to safely perform operations on one
214 // or more threads without the risk of the thread exiting during the
215 // operation.
216 //
217 // Note: The Threads_lock is currently more widely used than we
218 // would like. We are actively migrating Threads_lock uses to other
219 // mechanisms in order to reduce Threads_lock contention.
220
221 int Threads::_number_of_threads = 0;
222 int Threads::_number_of_non_daemon_threads = 0;
223 int Threads::_return_code = 0;
224 uintx Threads::_thread_claim_token = 1; // Never zero.
225
226 #ifdef ASSERT
227 bool Threads::_vm_complete = false;
228 #endif
229
230 // General purpose hook into Java code, run once when the VM is initialized.
231 // The Java library method itself may be changed independently from the VM.
232 static void call_postVMInitHook(TRAPS) {
233 Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_vm_PostVMInitHook(), THREAD);
234 if (klass != nullptr) {
235 JavaValue result(T_VOID);
236 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
237 vmSymbols::void_method_signature(),
238 CHECK);
239 }
240 }
241
242 // All NonJavaThreads (i.e., every non-JavaThread in the system).
243 void Threads::non_java_threads_do(ThreadClosure* tc) {
244 NoSafepointVerifier nsv;
245 for (NonJavaThread::Iterator njti; !njti.end(); njti.step()) {
246 tc->do_thread(njti.current());
247 }
248 }
249
250 // All JavaThreads
251 #define ALL_JAVA_THREADS(X) \
252 for (JavaThread* X : *ThreadsSMRSupport::get_java_thread_list())
253
254 // All JavaThreads
255 void Threads::java_threads_do(ThreadClosure* tc) {
256 assert_locked_or_safepoint(Threads_lock);
257 // ALL_JAVA_THREADS iterates through all JavaThreads.
258 ALL_JAVA_THREADS(p) {
259 tc->do_thread(p);
260 }
261 }
262
263 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system).
264 void Threads::threads_do(ThreadClosure* tc) {
265 assert_locked_or_safepoint(Threads_lock);
266 java_threads_do(tc);
267 non_java_threads_do(tc);
268 }
269
270 void Threads::possibly_parallel_threads_do(bool is_par, ThreadClosure* tc) {
271 assert_at_safepoint();
272
273 uintx claim_token = Threads::thread_claim_token();
274 ALL_JAVA_THREADS(p) {
275 if (p->claim_threads_do(is_par, claim_token)) {
276 tc->do_thread(p);
277 }
278 }
279 for (NonJavaThread::Iterator njti; !njti.end(); njti.step()) {
280 Thread* current = njti.current();
281 if (current->claim_threads_do(is_par, claim_token)) {
282 tc->do_thread(current);
283 }
284 }
285 }
286
287 // The system initialization in the library has three phases.
288 //
289 // Phase 1: java.lang.System class initialization
290 // java.lang.System is a primordial class loaded and initialized
291 // by the VM early during startup. java.lang.System.<clinit>
292 // only does registerNatives and keeps the rest of the class
293 // initialization work later until thread initialization completes.
294 //
295 // System.initPhase1 initializes the system properties, the static
296 // fields in, out, and err. Set up java signal handlers, OS-specific
297 // system settings, and thread group of the main thread.
298 static void call_initPhase1(TRAPS) {
299 Klass* klass = vmClasses::System_klass();
300 JavaValue result(T_VOID);
301 JavaCalls::call_static(&result, klass, vmSymbols::initPhase1_name(),
302 vmSymbols::void_method_signature(), CHECK);
303 }
304
305 // Phase 2. Module system initialization
306 // This will initialize the module system. Only java.base classes
307 // can be loaded until phase 2 completes.
308 //
309 // Call System.initPhase2 after the compiler initialization and jsr292
310 // classes get initialized because module initialization runs a lot of java
311 // code, that for performance reasons, should be compiled. Also, this will
312 // enable the startup code to use lambda and other language features in this
313 // phase and onward.
314 //
315 // After phase 2, The VM will begin search classes from -Xbootclasspath/a.
316 static void call_initPhase2(TRAPS) {
317 TraceTime timer("Initialize module system", TRACETIME_LOG(Info, startuptime));
318
319 Klass* klass = vmClasses::System_klass();
320
321 JavaValue result(T_INT);
322 JavaCallArguments args;
323 args.push_int(DisplayVMOutputToStderr);
324 args.push_int(log_is_enabled(Debug, init)); // print stack trace if exception thrown
325 JavaCalls::call_static(&result, klass, vmSymbols::initPhase2_name(),
326 vmSymbols::boolean_boolean_int_signature(), &args, CHECK);
327 if (result.get_jint() != JNI_OK) {
328 vm_exit_during_initialization(); // no message or exception
329 }
330
331 universe_post_module_init();
332
333 if (CDSConfig::is_using_aot_linked_classes()) {
334 AOTLinkedClassBulkLoader::load_non_javabase_boot_classes(THREAD);
335 if (CDSConfig::is_using_full_module_graph()) {
336 assert(SystemDictionary::java_platform_loader() != nullptr, "must be");
337 assert(SystemDictionary::java_system_loader() != nullptr, "must be");
338 AOTLinkedClassBulkLoader::load_platform_classes(THREAD);
339 AOTLinkedClassBulkLoader::load_app_classes(THREAD);
340 } else {
341 // Special case -- we assume that the final archive has the same module graph
342 // as the training run.
343 // AOTLinkedClassBulkLoader will be called for the platform/system loaders
344 // inside SystemDictionary::compute_java_loaders().
345 assert(CDSConfig::is_dumping_final_static_archive(), "must be");
346 assert(SystemDictionary::java_platform_loader() == nullptr, "must be");
347 assert(SystemDictionary::java_system_loader() == nullptr, "must be");
348 }
349 }
350
351 #ifndef PRODUCT
352 HeapShared::initialize_test_class_from_archive(THREAD);
353 #endif
354 }
355
356 // Phase 3. final setup - set security manager, system class loader and TCCL
357 //
358 // This will instantiate and set the security manager, set the system class
359 // loader as well as the thread context class loader. The security manager
360 // and system class loader may be a custom class loaded from -Xbootclasspath/a,
361 // other modules or the application's classpath.
362 static void call_initPhase3(TRAPS) {
363 Klass* klass = vmClasses::System_klass();
364 JavaValue result(T_VOID);
365 JavaCalls::call_static(&result, klass, vmSymbols::initPhase3_name(),
366 vmSymbols::void_method_signature(), CHECK);
367 }
368
369 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
370 TraceTime timer("Initialize java.lang classes", TRACETIME_LOG(Info, startuptime));
371
372 initialize_class(vmSymbols::java_lang_String(), CHECK);
373
374 // Inject CompactStrings value after the static initializers for String ran.
375 java_lang_String::set_compact_strings(CompactStrings);
376
377 // Initialize java_lang.System (needed before creating the thread)
378 initialize_class(vmSymbols::java_lang_System(), CHECK);
379 // The VM creates & returns objects of this class. Make sure it's initialized.
380 initialize_class(vmSymbols::java_lang_Class(), CHECK);
381 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
382 Handle thread_group = create_initial_thread_group(CHECK);
383 Universe::set_main_thread_group(thread_group());
384 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
385 create_initial_thread(thread_group, main_thread, CHECK);
386
387 HeapShared::init_box_classes(CHECK);
388
389 // The VM creates objects of this class.
390 initialize_class(vmSymbols::java_lang_Module(), CHECK);
391
392 #ifdef ASSERT
393 InstanceKlass *k = vmClasses::UnsafeConstants_klass();
394 assert(k->is_not_initialized(), "UnsafeConstants should not already be initialized");
395 #endif
396
397 // initialize the hardware-specific constants needed by Unsafe
398 initialize_class(vmSymbols::jdk_internal_misc_UnsafeConstants(), CHECK);
399 jdk_internal_misc_UnsafeConstants::set_unsafe_constants();
400
401 // The VM preresolves methods to these classes. Make sure that they get initialized
402 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
403 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
404
405 // Phase 1 of the system initialization in the library, java.lang.System class initialization
406 call_initPhase1(CHECK);
407
408 // Get the Java runtime name, version, and vendor info after java.lang.System is initialized.
409 // Some values are actually configure-time constants but some can be set via the jlink tool and
410 // so must be read dynamically. We treat them all the same.
411 InstanceKlass* ik = SystemDictionary::find_instance_klass(THREAD, vmSymbols::java_lang_VersionProps(),
412 Handle(), Handle());
413 {
414 ResourceMark rm(main_thread);
415 JDK_Version::set_java_version(get_java_version_info(ik, vmSymbols::java_version_name()));
416
417 JDK_Version::set_runtime_name(get_java_version_info(ik, vmSymbols::java_runtime_name_name()));
418
419 JDK_Version::set_runtime_version(get_java_version_info(ik, vmSymbols::java_runtime_version_name()));
420
421 JDK_Version::set_runtime_vendor_version(get_java_version_info(ik, vmSymbols::java_runtime_vendor_version_name()));
422
423 JDK_Version::set_runtime_vendor_vm_bug_url(get_java_version_info(ik, vmSymbols::java_runtime_vendor_vm_bug_url_name()));
424 }
425
426 // an instance of OutOfMemory exception has been allocated earlier
427 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
428 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
429 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
430 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
431 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
432 initialize_class(vmSymbols::java_lang_ArrayIndexOutOfBoundsException(), CHECK);
433 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
434 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
435 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
436 }
437
438 bool Threads::initialize_compilation(TRAPS) {
439 // initialize compiler(s)
440 bool force_JVMCI_initialization = false;
441
442 #if defined(COMPILER1) || COMPILER2_OR_JVMCI
443 bool init_compilation = true;
444 #if INCLUDE_JVMCI
445 if (EnableJVMCI) {
446 // Initialize JVMCI eagerly when it is explicitly requested.
447 // Or when JVMCILibDumpJNIConfig or JVMCIPrintProperties is enabled.
448 force_JVMCI_initialization = EagerJVMCI || JVMCIPrintProperties || JVMCILibDumpJNIConfig;
449 if (!force_JVMCI_initialization && UseJVMCICompiler && !UseJVMCINativeLibrary && (!UseInterpreter || !BackgroundCompilation)) {
450 // Force initialization of jarjvmci otherwise requests for blocking
451 // compilations will not actually block until jarjvmci is initialized.
452 force_JVMCI_initialization = true;
453 }
454 if (JVMCIPrintProperties || JVMCILibDumpJNIConfig) {
455 // Both JVMCILibDumpJNIConfig and JVMCIPrintProperties exit the VM
456 // so compilation should be disabled. This prevents dumping or
457 // printing from happening more than once.
458 init_compilation = false;
459 }
460 }
461 #endif
462 if (init_compilation) {
463 CompileBroker::compilation_init(CHECK_false);
464 }
465 #endif
466
467 return force_JVMCI_initialization;
468 }
469
470 void Threads::initialize_jsr292_core_classes(TRAPS) {
471 TraceTime timer("Initialize java.lang.invoke classes", TRACETIME_LOG(Info, startuptime));
472
473 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
474 initialize_class(vmSymbols::java_lang_invoke_ResolvedMethodName(), CHECK);
475 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
476 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
477
478 if (UseSharedSpaces) {
479 HeapShared::initialize_java_lang_invoke(CHECK);
480 }
481 }
482
483 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
484 extern void JDK_Version_init();
485
486 // Preinitialize version info.
487 VM_Version::early_initialize();
488
489 // Check version
490 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
491
492 // Initialize library-based TLS
493 ThreadLocalStorage::init();
494
495 // Initialize the output stream module
496 ostream_init();
497
498 // Process java launcher properties.
499 Arguments::process_sun_java_launcher_properties(args);
500
501 // Initialize the os module
502 os::init();
503
504 MACOS_AARCH64_ONLY(os::current_thread_enable_wx(WXWrite));
505
506 // Record VM creation timing statistics
507 TraceVmCreationTime create_vm_timer;
508 create_vm_timer.start();
509
510 // Initialize system properties.
511 Arguments::init_system_properties();
512
513 // So that JDK version can be used as a discriminator when parsing arguments
514 JDK_Version_init();
515
516 // Update/Initialize System properties after JDK version number is known
517 Arguments::init_version_specific_system_properties();
518
519 // Make sure to initialize log configuration *before* parsing arguments
520 LogConfiguration::initialize(create_vm_timer.begin_time());
521
522 // Parse arguments
523 // Note: this internally calls os::init_container_support()
524 jint parse_result = Arguments::parse(args);
525 if (parse_result != JNI_OK) return parse_result;
526
527 // Initialize NMT right after argument parsing to keep the pre-NMT-init window small.
528 MemTracker::initialize();
529
530 os::init_before_ergo();
531
532 jint ergo_result = Arguments::apply_ergo();
533 if (ergo_result != JNI_OK) return ergo_result;
534
535 // Final check of all ranges after ergonomics which may change values.
536 if (!JVMFlagLimit::check_all_ranges()) {
537 return JNI_EINVAL;
538 }
539
540 // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
541 bool constraint_result = JVMFlagLimit::check_all_constraints(JVMFlagConstraintPhase::AfterErgo);
542 if (!constraint_result) {
543 return JNI_EINVAL;
544 }
545
546 if (PauseAtStartup) {
547 os::pause();
548 }
549
550 HOTSPOT_VM_INIT_BEGIN();
551
552 // Timing (must come after argument parsing)
553 TraceTime timer("Create VM", TRACETIME_LOG(Info, startuptime));
554
555 // Initialize the os module after parsing the args
556 jint os_init_2_result = os::init_2();
557 if (os_init_2_result != JNI_OK) return os_init_2_result;
558
559 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT
560 // Initialize assert poison page mechanism.
561 if (ShowRegistersOnAssert) {
562 initialize_assert_poison();
563 }
564 #endif // CAN_SHOW_REGISTERS_ON_ASSERT
565
566 SafepointMechanism::initialize();
567
568 jint adjust_after_os_result = Arguments::adjust_after_os();
569 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
570
571 // Initialize output stream logging
572 ostream_init_log();
573
574 // Launch -agentlib/-agentpath and converted -Xrun agents
575 JvmtiAgentList::load_agents();
576
577 // Initialize Threads state
578 _number_of_threads = 0;
579 _number_of_non_daemon_threads = 0;
580
581 // Initialize global data structures and create system classes in heap
582 vm_init_globals();
583
584 #if INCLUDE_JVMCI
585 if (JVMCICounterSize > 0) {
586 JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtJVMCI);
587 memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize);
588 } else {
589 JavaThread::_jvmci_old_thread_counters = nullptr;
590 }
591 #endif // INCLUDE_JVMCI
592
593 // Initialize OopStorage for threadObj
594 JavaThread::_thread_oop_storage = OopStorageSet::create_strong("Thread OopStorage", mtThread);
595
596 // Attach the main thread to this os thread
597 JavaThread* main_thread = new JavaThread();
598 main_thread->set_thread_state(_thread_in_vm);
599 main_thread->initialize_thread_current();
600 // must do this before set_active_handles
601 main_thread->record_stack_base_and_size();
602 main_thread->register_thread_stack_with_NMT();
603 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
604 MACOS_AARCH64_ONLY(main_thread->init_wx());
605
606 MutexLockerImpl::init_counters(); // depends on mutex_init(), perfMemory_init(), and Thread::initialize_thread_current().
607
608 if (!main_thread->set_as_starting_thread()) {
609 vm_shutdown_during_initialization(
610 "Failed necessary internal allocation. Out of swap space");
611 main_thread->smr_delete();
612 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
613 return JNI_ENOMEM;
614 }
615
616 // Enable guard page *after* os::create_main_thread(), otherwise it would
617 // crash Linux VM, see notes in os_linux.cpp.
618 main_thread->stack_overflow_state()->create_stack_guard_pages();
619
620 // Initialize Java-Level synchronization subsystem
621 ObjectMonitor::Initialize();
622 ObjectSynchronizer::initialize();
623
624 Deoptimization::init_counters();
625 VMThread::init_counters();
626
627 // Initialize global modules
628 jint status = init_globals();
629 if (status != JNI_OK) {
630 main_thread->smr_delete();
631 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
632 return status;
633 }
634 if (xtty != nullptr)
635 xtty->elem("vm_main_thread thread='" UINTX_FORMAT "'",
636 (uintx) main_thread->osthread()->thread_id());
637
638 // Create WatcherThread as soon as we can since we need it in case
639 // of hangs during error reporting.
640 WatcherThread::start();
641
642 // Add main_thread to threads list to finish barrier setup with
643 // on_thread_attach. Should be before starting to build Java objects in
644 // init_globals2, which invokes barriers.
645 {
646 MutexLocker mu(Threads_lock);
647 Threads::add(main_thread);
648 }
649
650 status = init_globals2();
651 if (status != JNI_OK) {
652 Threads::remove(main_thread, false);
653 // It is possible that we managed to fully initialize Universe but have then
654 // failed by throwing an exception. In that case our caller JNI_CreateJavaVM
655 // will want to report it, so we can't delete the main thread.
656 if (!main_thread->has_pending_exception()) {
657 main_thread->smr_delete();
658 }
659 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
660 return status;
661 }
662
663 JFR_ONLY(Jfr::on_create_vm_1();)
664
665 // Should be done after the heap is fully created
666 main_thread->cache_global_variables();
667
668 // Any JVMTI raw monitors entered in onload will transition into
669 // real raw monitor. VM is setup enough here for raw monitor enter.
670 JvmtiExport::transition_pending_onload_raw_monitors();
671
672 // Create the VMThread
673 { TraceTime timer("Start VMThread", TRACETIME_LOG(Info, startuptime));
674
675 VMThread::create();
676 VMThread* vmthread = VMThread::vm_thread();
677
678 if (!os::create_thread(vmthread, os::vm_thread)) {
679 vm_exit_during_initialization("Cannot create VM thread. "
680 "Out of system resources.");
681 }
682
683 // Wait for the VM thread to become ready, and VMThread::run to initialize
684 // Monitors can have spurious returns, must always check another state flag
685 {
686 MonitorLocker ml(Notify_lock);
687 os::start_thread(vmthread);
688 while (!vmthread->is_running()) {
689 ml.wait();
690 }
691 }
692 }
693
694 assert(Universe::is_fully_initialized(), "not initialized");
695 if (VerifyDuringStartup) {
696 // Make sure we're starting with a clean slate.
697 VM_Verify verify_op;
698 VMThread::execute(&verify_op);
699 }
700
701 // We need this to update the java.vm.info property in case any flags used
702 // to initially define it have been changed. This is needed for both CDS
703 // since UseSharedSpaces may be changed after java.vm.info
704 // is initially computed. See Abstract_VM_Version::vm_info_string().
705 // This update must happen before we initialize the java classes, but
706 // after any initialization logic that might modify the flags.
707 Arguments::update_vm_info_property(VM_Version::vm_info_string());
708
709 JavaThread* THREAD = JavaThread::current(); // For exception macros.
710 HandleMark hm(THREAD);
711
712 // Always call even when there are not JVMTI environments yet, since environments
713 // may be attached late and JVMTI must track phases of VM execution
714 JvmtiExport::enter_early_start_phase();
715
716 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
717 JvmtiExport::post_early_vm_start();
718
719 // Launch -Xrun agents early if EagerXrunInit is set
720 if (EagerXrunInit) {
721 JvmtiAgentList::load_xrun_agents();
722 }
723
724 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
725
726 quicken_jni_functions();
727
728 // No more stub generation allowed after that point.
729 StubCodeDesc::freeze();
730
731 // Set flag that basic initialization has completed. Used by exceptions and various
732 // debug stuff, that does not work until all basic classes have been initialized.
733 set_init_completed();
734
735 LogConfiguration::post_initialize();
736 Metaspace::post_initialize();
737 MutexLockerImpl::post_initialize();
738
739 HOTSPOT_VM_INIT_END();
740
741 // record VM initialization completion time
742 #if INCLUDE_MANAGEMENT
743 Management::record_vm_init_completed();
744 #endif // INCLUDE_MANAGEMENT
745
746 log_info(os)("Initialized VM with process ID %d", os::current_process_id());
747
748 // Signal Dispatcher needs to be started before VMInit event is posted
749 os::initialize_jdk_signal_support(CHECK_JNI_ERR);
750
751 // Start Attach Listener if +StartAttachListener or it can't be started lazily
752 if (!DisableAttachMechanism) {
753 AttachListener::vm_start();
754 if (StartAttachListener || AttachListener::init_at_startup()) {
755 AttachListener::init();
756 }
757 }
758
759 // Launch -Xrun agents if EagerXrunInit is not set.
760 if (!EagerXrunInit) {
761 JvmtiAgentList::load_xrun_agents();
762 }
763
764 Arena::start_chunk_pool_cleaner_task();
765
766 // Start the service thread
767 // The service thread enqueues JVMTI deferred events and does various hashtable
768 // and other cleanups. Needs to start before the compilers start posting events.
769 ServiceThread::initialize();
770
771 // Start the monitor deflation thread:
772 MonitorDeflationThread::initialize();
773
774 #if INCLUDE_CDS
775 // Start the method sampler
776 MethodProfiler::initialize();
777 #endif
778
779 bool force_JVMCI_initialization = initialize_compilation(CHECK_JNI_ERR);
780
781 AOTLinkedClassBulkLoader::init_javabase_preloaded_classes(CHECK_JNI_ERR);
782
783 // Start string deduplication thread if requested.
784 if (StringDedup::is_enabled()) {
785 StringDedup::start();
786 }
787
788 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
789 // It is done after compilers are initialized, because otherwise compilations of
790 // signature polymorphic MH intrinsics can be missed
791 // (see SystemDictionary::find_method_handle_intrinsic).
792 initialize_jsr292_core_classes(CHECK_JNI_ERR);
793
794 // This will initialize the module system. Only java.base classes can be
795 // loaded until phase 2 completes
796 call_initPhase2(CHECK_JNI_ERR);
797
798 JFR_ONLY(Jfr::on_create_vm_2();)
799
800 // Always call even when there are not JVMTI environments yet, since environments
801 // may be attached late and JVMTI must track phases of VM execution
802 JvmtiExport::enter_start_phase();
803
804 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
805 JvmtiExport::post_vm_start();
806
807 // Final system initialization including security manager and system class loader
808 call_initPhase3(CHECK_JNI_ERR);
809
810 // cache the system and platform class loaders
811 SystemDictionary::compute_java_loaders(CHECK_JNI_ERR);
812
813 // Initiate replay training processing once preloading is over.
814 CompileBroker::init_training_replay();
815
816 AOTLinkedClassBulkLoader::replay_training_at_init_for_preloaded_classes(CHECK_JNI_ERR);
817
818 if (Continuations::enabled()) {
819 // Initialize Continuation class now so that failure to create enterSpecial/doYield
820 // special nmethods due to limited CodeCache size can be treated as a fatal error at
821 // startup with the proper message that CodeCache size is too small.
822 initialize_class(vmSymbols::jdk_internal_vm_Continuation(), CHECK_JNI_ERR);
823 }
824
825 #if INCLUDE_CDS
826 // capture the module path info from the ModuleEntryTable
827 ClassLoader::initialize_module_path(THREAD);
828 if (HAS_PENDING_EXCEPTION) {
829 java_lang_Throwable::print(PENDING_EXCEPTION, tty);
830 vm_exit_during_initialization("ClassLoader::initialize_module_path() failed unexpectedly");
831 }
832 #endif
833
834 #if INCLUDE_JVMCI
835 if (force_JVMCI_initialization) {
836 JVMCI::initialize_compiler(CHECK_JNI_ERR);
837 }
838 #endif
839
840 if (PrecompileCode) {
841 Precompiler::compile_cached_code(CHECK_JNI_ERR);
842 if (PrecompileOnlyAndExit) {
843 SCCache::close();
844 log_vm_init_stats(true /* use_tty */);
845 vm_direct_exit(0, "Code precompiation is over");
846 }
847 }
848
849 #if defined(COMPILER2)
850 // Pre-load cached compiled methods
851 SCCache::preload_code(CHECK_JNI_ERR);
852 #endif
853
854 if (NativeHeapTrimmer::enabled()) {
855 NativeHeapTrimmer::initialize();
856 }
857
858 // Always call even when there are not JVMTI environments yet, since environments
859 // may be attached late and JVMTI must track phases of VM execution
860 JvmtiExport::enter_live_phase();
861
862 // Make perfmemory accessible
863 PerfMemory::set_accessible(true);
864
865 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
866 JvmtiExport::post_vm_initialized();
867
868 JFR_ONLY(Jfr::on_create_vm_3();)
869
870 #if INCLUDE_MANAGEMENT
871 Management::initialize(THREAD);
872
873 if (HAS_PENDING_EXCEPTION) {
874 // management agent fails to start possibly due to
875 // configuration problem and is responsible for printing
876 // stack trace if appropriate. Simply exit VM.
877 vm_exit(1);
878 }
879 #endif // INCLUDE_MANAGEMENT
880
881 StatSampler::engage();
882 if (CheckJNICalls) JniPeriodicChecker::engage();
883
884 call_postVMInitHook(THREAD);
885 // The Java side of PostVMInitHook.run must deal with all
886 // exceptions and provide means of diagnosis.
887 if (HAS_PENDING_EXCEPTION) {
888 CLEAR_PENDING_EXCEPTION;
889 }
890
891 // Let WatcherThread run all registered periodic tasks now.
892 // NOTE: All PeriodicTasks should be registered by now. If they
893 // aren't, late joiners might appear to start slowly (we might
894 // take a while to process their first tick).
895 WatcherThread::run_all_tasks();
896
897 create_vm_timer.end();
898 #ifdef ASSERT
899 _vm_complete = true;
900 #endif
901
902 if (CDSConfig::is_dumping_classic_static_archive()) {
903 // Classic -Xshare:dump, aka "old workflow"
904 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
905 } else if (CDSConfig::is_dumping_final_static_archive()) {
906 // TODO: copy the verification and loader constraints from preimage to final image
907 // TODO: load archived classes for custom loaders as well.
908 log_info(cds)("Dumping final image of CacheDataStore %s", CacheDataStore);
909 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
910 vm_direct_exit(0, "CacheDataStore dumping is complete");
911 }
912
913 log_info(init)("At VM initialization completion:");
914 log_vm_init_stats(false /* use_tty */);
915
916 if (UsePerfData) {
917 if (ProfileVMLocks) {
918 main_thread->set_profile_vm_locks(true);
919 }
920 if (ProfileVMCalls) {
921 main_thread->set_profile_vm_calls(true);
922 }
923 if (ProfileRuntimeCalls) {
924 main_thread->set_profile_rt_calls(true);
925 }
926 if (ProfileVMOps) {
927 main_thread->set_profile_vm_ops(true);
928 }
929 }
930
931 return JNI_OK;
932 }
933
934 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
935 // the program falls off the end of main(). Another VM exit path is through
936 // vm_exit(), when the program calls System.exit() to return a value, or when
937 // there is a serious error in VM.
938 // These two separate shutdown paths are not exactly the same, but they share
939 // Shutdown.shutdown() at Java level and before_exit() and VM_Exit op at VM level.
940 //
941 // Shutdown sequence:
942 // + Shutdown native memory tracking if it is on
943 // + Wait until we are the last non-daemon thread to execute
944 // <-- every thing is still working at this moment -->
945 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
946 // shutdown hooks
947 // + Call before_exit(), prepare for VM exit
948 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
949 // currently the only user of this mechanism is File.deleteOnExit())
950 // > stop StatSampler, watcher thread,
951 // post thread end and vm death events to JVMTI,
952 // stop signal thread
953 // + Call JavaThread::exit(), it will:
954 // > release JNI handle blocks, remove stack guard pages
955 // > remove this thread from Threads list
956 // <-- no more Java code from this thread after this point -->
957 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
958 // the compiler threads at safepoint
959 // <-- do not use anything that could get blocked by Safepoint -->
960 // + Disable tracing at JNI/JVM barriers
961 // + Set _vm_exited flag for threads that are still running native code
962 // + Call exit_globals()
963 // > deletes tty
964 // > deletes PerfMemory resources
965 // + Delete this thread
966 // + Return to caller
967
968 void Threads::destroy_vm() {
969 JavaThread* thread = JavaThread::current();
970
971 #ifdef ASSERT
972 _vm_complete = false;
973 #endif
974 // Wait until we are the last non-daemon thread to execute, or
975 // if we are a daemon then wait until the last non-daemon thread has
976 // executed.
977 bool daemon = java_lang_Thread::is_daemon(thread->threadObj());
978 int expected = daemon ? 0 : 1;
979 {
980 MonitorLocker nu(Threads_lock);
981 while (Threads::number_of_non_daemon_threads() > expected)
982 // This wait should make safepoint checks, wait without a timeout.
983 nu.wait(0);
984 }
985
986 EventShutdown e;
987 if (e.should_commit()) {
988 e.set_reason("No remaining non-daemon Java threads");
989 e.commit();
990 }
991
992 // Hang forever on exit if we are reporting an error.
993 if (ShowMessageBoxOnError && VMError::is_error_reported()) {
994 os::infinite_sleep();
995 }
996 os::wait_for_keypress_at_exit();
997
998 // run Java level shutdown hooks
999 thread->invoke_shutdown_hooks();
1000
1001 before_exit(thread);
1002
1003 thread->exit(true);
1004
1005 // We are no longer on the main thread list but could still be in a
1006 // secondary list where another thread may try to interact with us.
1007 // So wait until all such interactions are complete before we bring
1008 // the VM to the termination safepoint. Normally this would be done
1009 // using thread->smr_delete() below where we delete the thread, but
1010 // we can't call that after the termination safepoint is active as
1011 // we will deadlock on the Threads_lock. Once all interactions are
1012 // complete it is safe to directly delete the thread at any time.
1013 ThreadsSMRSupport::wait_until_not_protected(thread);
1014
1015 // Stop VM thread.
1016 {
1017 // 4945125 The vm thread comes to a safepoint during exit.
1018 // GC vm_operations can get caught at the safepoint, and the
1019 // heap is unparseable if they are caught. Grab the Heap_lock
1020 // to prevent this. The GC vm_operations will not be able to
1021 // queue until after the vm thread is dead. After this point,
1022 // we'll never emerge out of the safepoint before the VM exits.
1023 // Assert that the thread is terminated so that acquiring the
1024 // Heap_lock doesn't cause the terminated thread to participate in
1025 // the safepoint protocol.
1026
1027 assert(thread->is_terminated(), "must be terminated here");
1028 MutexLocker ml(Heap_lock);
1029
1030 VMThread::wait_for_vm_thread_exit();
1031 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
1032 VMThread::destroy();
1033 }
1034
1035 // Now, all Java threads are gone except daemon threads. Daemon threads
1036 // running Java code or in VM are stopped by the Safepoint. However,
1037 // daemon threads executing native code are still running. But they
1038 // will be stopped at native=>Java/VM barriers. Note that we can't
1039 // simply kill or suspend them, as it is inherently deadlock-prone.
1040
1041 VM_Exit::set_vm_exited();
1042
1043 // Clean up ideal graph printers after the VMThread has started
1044 // the final safepoint which will block all the Compiler threads.
1045 // Note that this Thread has already logically exited so the
1046 // clean_up() function's use of a JavaThreadIteratorWithHandle
1047 // would be a problem except set_vm_exited() has remembered the
1048 // shutdown thread which is granted a policy exception.
1049 #if defined(COMPILER2) && !defined(PRODUCT)
1050 IdealGraphPrinter::clean_up();
1051 #endif
1052
1053 notify_vm_shutdown();
1054
1055 // exit_globals() will delete tty
1056 exit_globals();
1057
1058 // Deleting the shutdown thread here is safe. See comment on
1059 // wait_until_not_protected() above.
1060 delete thread;
1061
1062 #if INCLUDE_JVMCI
1063 if (JVMCICounterSize > 0) {
1064 FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters);
1065 }
1066 #endif
1067
1068 LogConfiguration::finalize();
1069 }
1070
1071
1072 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
1073 if (version == JNI_VERSION_1_1) return JNI_TRUE;
1074 return is_supported_jni_version(version);
1075 }
1076
1077
1078 jboolean Threads::is_supported_jni_version(jint version) {
1079 if (version == JNI_VERSION_1_2) return JNI_TRUE;
1080 if (version == JNI_VERSION_1_4) return JNI_TRUE;
1081 if (version == JNI_VERSION_1_6) return JNI_TRUE;
1082 if (version == JNI_VERSION_1_8) return JNI_TRUE;
1083 if (version == JNI_VERSION_9) return JNI_TRUE;
1084 if (version == JNI_VERSION_10) return JNI_TRUE;
1085 if (version == JNI_VERSION_19) return JNI_TRUE;
1086 if (version == JNI_VERSION_20) return JNI_TRUE;
1087 if (version == JNI_VERSION_21) return JNI_TRUE;
1088 if (version == JNI_VERSION_24) return JNI_TRUE;
1089 return JNI_FALSE;
1090 }
1091
1092 void Threads::add(JavaThread* p, bool force_daemon) {
1093 // The threads lock must be owned at this point
1094 assert(Threads_lock->owned_by_self(), "must have threads lock");
1095
1096 BarrierSet::barrier_set()->on_thread_attach(p);
1097
1098 // Once a JavaThread is added to the Threads list, smr_delete() has
1099 // to be used to delete it. Otherwise we can just delete it directly.
1100 p->set_on_thread_list();
1101
1102 _number_of_threads++;
1103 oop threadObj = p->threadObj();
1104 bool daemon = true;
1105 // Bootstrapping problem: threadObj can be null for initial
1106 // JavaThread (or for threads attached via JNI)
1107 if (!force_daemon &&
1108 (threadObj == nullptr || !java_lang_Thread::is_daemon(threadObj))) {
1109 _number_of_non_daemon_threads++;
1110 daemon = false;
1111 }
1112
1113 ThreadService::add_thread(p, daemon);
1114
1115 // Maintain fast thread list
1116 ThreadsSMRSupport::add_thread(p);
1117
1118 // Increase the ObjectMonitor ceiling for the new thread.
1119 ObjectSynchronizer::inc_in_use_list_ceiling();
1120
1121 // Possible GC point.
1122 Events::log(Thread::current(), "Thread added: " INTPTR_FORMAT, p2i(p));
1123
1124 // Make new thread known to active EscapeBarrier
1125 EscapeBarrier::thread_added(p);
1126 }
1127
1128 void Threads::remove(JavaThread* p, bool is_daemon) {
1129 // Extra scope needed for Thread_lock, so we can check
1130 // that we do not remove thread without safepoint code notice
1131 { MonitorLocker ml(Threads_lock);
1132
1133 if (ThreadIdTable::is_initialized()) {
1134 // This cleanup must be done before the current thread's GC barrier
1135 // is detached since we need to touch the threadObj oop.
1136 jlong tid = SharedRuntime::get_java_tid(p);
1137 ThreadIdTable::remove_thread(tid);
1138 }
1139
1140 // BarrierSet state must be destroyed after the last thread transition
1141 // before the thread terminates. Thread transitions result in calls to
1142 // StackWatermarkSet::on_safepoint(), which performs GC processing,
1143 // requiring the GC state to be alive.
1144 BarrierSet::barrier_set()->on_thread_detach(p);
1145 if (p->is_exiting()) {
1146 // If we got here via JavaThread::exit(), then we remember that the
1147 // thread's GC barrier has been detached. We don't do this when we get
1148 // here from another path, e.g., cleanup_failed_attach_current_thread().
1149 p->set_terminated(JavaThread::_thread_gc_barrier_detached);
1150 }
1151
1152 assert(ThreadsSMRSupport::get_java_thread_list()->includes(p), "p must be present");
1153
1154 // Maintain fast thread list
1155 ThreadsSMRSupport::remove_thread(p);
1156
1157 _number_of_threads--;
1158 if (!is_daemon) {
1159 _number_of_non_daemon_threads--;
1160
1161 // If this is the last non-daemon thread then we need to do
1162 // a notify on the Threads_lock so a thread waiting
1163 // on destroy_vm will wake up. But that thread could be a daemon
1164 // or non-daemon, so we notify for both the 0 and 1 case.
1165 if (number_of_non_daemon_threads() <= 1) {
1166 ml.notify_all();
1167 }
1168 }
1169 ThreadService::remove_thread(p, is_daemon);
1170
1171 // Make sure that safepoint code disregard this thread. This is needed since
1172 // the thread might mess around with locks after this point. This can cause it
1173 // to do callbacks into the safepoint code. However, the safepoint code is not aware
1174 // of this thread since it is removed from the queue.
1175 p->set_terminated(JavaThread::_thread_terminated);
1176
1177 // Notify threads waiting in EscapeBarriers
1178 EscapeBarrier::thread_removed(p);
1179 } // unlock Threads_lock
1180
1181 // Reduce the ObjectMonitor ceiling for the exiting thread.
1182 ObjectSynchronizer::dec_in_use_list_ceiling();
1183
1184 // Since Events::log uses a lock, we grab it outside the Threads_lock
1185 Events::log(Thread::current(), "Thread exited: " INTPTR_FORMAT, p2i(p));
1186 }
1187
1188 // Operations on the Threads list for GC. These are not explicitly locked,
1189 // but the garbage collector must provide a safe context for them to run.
1190 // In particular, these things should never be called when the Threads_lock
1191 // is held by some other thread. (Note: the Safepoint abstraction also
1192 // uses the Threads_lock to guarantee this property. It also makes sure that
1193 // all threads gets blocked when exiting or starting).
1194
1195 void Threads::oops_do(OopClosure* f, NMethodClosure* cf) {
1196 ALL_JAVA_THREADS(p) {
1197 p->oops_do(f, cf);
1198 }
1199 VMThread::vm_thread()->oops_do(f, cf);
1200 }
1201
1202 void Threads::change_thread_claim_token() {
1203 if (++_thread_claim_token == 0) {
1204 // On overflow of the token counter, there is a risk of future
1205 // collisions between a new global token value and a stale token
1206 // for a thread, because not all iterations visit all threads.
1207 // (Though it's pretty much a theoretical concern for non-trivial
1208 // token counter sizes.) To deal with the possibility, reset all
1209 // the thread tokens to zero on global token overflow.
1210 struct ResetClaims : public ThreadClosure {
1211 virtual void do_thread(Thread* t) {
1212 t->claim_threads_do(false, 0);
1213 }
1214 } reset_claims;
1215 Threads::threads_do(&reset_claims);
1216 // On overflow, update the global token to non-zero, to
1217 // avoid the special "never claimed" initial thread value.
1218 _thread_claim_token = 1;
1219 }
1220 }
1221
1222 #ifdef ASSERT
1223 static void assert_thread_claimed(const char* kind, Thread* t, uintx expected) {
1224 const uintx token = t->threads_do_token();
1225 assert(token == expected,
1226 "%s " PTR_FORMAT " has incorrect value " UINTX_FORMAT " != "
1227 UINTX_FORMAT, kind, p2i(t), token, expected);
1228 }
1229
1230 void Threads::assert_all_threads_claimed() {
1231 ALL_JAVA_THREADS(p) {
1232 assert_thread_claimed("JavaThread", p, _thread_claim_token);
1233 }
1234
1235 struct NJTClaimedVerifierClosure : public ThreadClosure {
1236 uintx _thread_claim_token;
1237
1238 NJTClaimedVerifierClosure(uintx thread_claim_token) : ThreadClosure(), _thread_claim_token(thread_claim_token) { }
1239
1240 virtual void do_thread(Thread* thread) override {
1241 assert_thread_claimed("Non-JavaThread", VMThread::vm_thread(), _thread_claim_token);
1242 }
1243 } tc(_thread_claim_token);
1244
1245 non_java_threads_do(&tc);
1246 }
1247 #endif // ASSERT
1248
1249 class ParallelOopsDoThreadClosure : public ThreadClosure {
1250 private:
1251 OopClosure* _f;
1252 NMethodClosure* _cf;
1253 public:
1254 ParallelOopsDoThreadClosure(OopClosure* f, NMethodClosure* cf) : _f(f), _cf(cf) {}
1255 void do_thread(Thread* t) {
1256 t->oops_do(_f, _cf);
1257 }
1258 };
1259
1260 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, NMethodClosure* cf) {
1261 ParallelOopsDoThreadClosure tc(f, cf);
1262 possibly_parallel_threads_do(is_par, &tc);
1263 }
1264
1265 void Threads::metadata_do(MetadataClosure* f) {
1266 ALL_JAVA_THREADS(p) {
1267 p->metadata_do(f);
1268 }
1269 }
1270
1271 class ThreadHandlesClosure : public ThreadClosure {
1272 void (*_f)(Metadata*);
1273 public:
1274 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
1275 virtual void do_thread(Thread* thread) {
1276 thread->metadata_handles_do(_f);
1277 }
1278 };
1279
1280 void Threads::metadata_handles_do(void f(Metadata*)) {
1281 // Only walk the Handles in Thread.
1282 ThreadHandlesClosure handles_closure(f);
1283 threads_do(&handles_closure);
1284 }
1285
1286 #if INCLUDE_JVMTI
1287 // Get Java threads that are waiting to enter or re-enter the specified monitor.
1288 // Java threads that are executing mounted virtual threads are not included.
1289 GrowableArray<JavaThread*>* Threads::get_pending_threads(ThreadsList * t_list,
1290 int count,
1291 address monitor) {
1292 assert(Thread::current()->is_VM_thread(), "Must be the VM thread");
1293 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
1294
1295 int i = 0;
1296 for (JavaThread* p : *t_list) {
1297 if (!p->can_call_java()) continue;
1298
1299 oop thread_oop = JvmtiEnvBase::get_vthread_or_thread_oop(p);
1300 if (thread_oop->is_a(vmClasses::BaseVirtualThread_klass())) {
1301 continue;
1302 }
1303 // The first stage of async deflation does not affect any field
1304 // used by this comparison so the ObjectMonitor* is usable here.
1305 address pending = (address)p->current_pending_monitor();
1306 address waiting = (address)p->current_waiting_monitor();
1307 // do not include virtual threads to the list
1308 jint state = JvmtiEnvBase::get_thread_state(thread_oop, p);
1309 if (pending == monitor || (waiting == monitor &&
1310 (state & JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER))
1311 ) { // found a match
1312 if (i < count) result->append(p); // save the first count matches
1313 i++;
1314 }
1315 }
1316
1317 return result;
1318 }
1319 #endif // INCLUDE_JVMTI
1320
1321 JavaThread *Threads::owning_thread_from_monitor_owner(ThreadsList * t_list,
1322 address owner) {
1323 assert(LockingMode != LM_LIGHTWEIGHT, "Not with new lightweight locking");
1324 // null owner means not locked so we can skip the search
1325 if (owner == nullptr) return nullptr;
1326
1327 for (JavaThread* p : *t_list) {
1328 // first, see if owner is the address of a Java thread
1329 if (owner == (address)p) return p;
1330 }
1331
1332 // Cannot assert on lack of success here since this function may be
1333 // used by code that is trying to report useful problem information
1334 // like deadlock detection.
1335 if (LockingMode == LM_MONITOR) return nullptr;
1336
1337 // If we didn't find a matching Java thread and we didn't force use of
1338 // heavyweight monitors, then the owner is the stack address of the
1339 // Lock Word in the owning Java thread's stack.
1340 //
1341 JavaThread* the_owner = nullptr;
1342 for (JavaThread* q : *t_list) {
1343 if (q->is_lock_owned(owner)) {
1344 the_owner = q;
1345 break;
1346 }
1347 }
1348
1349 // cannot assert on lack of success here; see above comment
1350 return the_owner;
1351 }
1352
1353 JavaThread* Threads::owning_thread_from_object(ThreadsList * t_list, oop obj) {
1354 assert(LockingMode == LM_LIGHTWEIGHT, "Only with new lightweight locking");
1355 for (JavaThread* q : *t_list) {
1356 // Need to start processing before accessing oops in the thread.
1357 StackWatermark* watermark = StackWatermarkSet::get(q, StackWatermarkKind::gc);
1358 if (watermark != nullptr) {
1359 watermark->start_processing();
1360 }
1361
1362 if (q->lock_stack().contains(obj)) {
1363 return q;
1364 }
1365 }
1366 return nullptr;
1367 }
1368
1369 JavaThread* Threads::owning_thread_from_monitor(ThreadsList* t_list, ObjectMonitor* monitor) {
1370 if (LockingMode == LM_LIGHTWEIGHT) {
1371 if (monitor->is_owner_anonymous()) {
1372 return owning_thread_from_object(t_list, monitor->object());
1373 } else {
1374 Thread* owner = reinterpret_cast<Thread*>(monitor->owner());
1375 assert(owner == nullptr || owner->is_Java_thread(), "only JavaThreads own monitors");
1376 return reinterpret_cast<JavaThread*>(owner);
1377 }
1378 } else {
1379 address owner = (address)monitor->owner();
1380 return owning_thread_from_monitor_owner(t_list, owner);
1381 }
1382 }
1383
1384 class PrintOnClosure : public ThreadClosure {
1385 private:
1386 outputStream* _st;
1387
1388 public:
1389 PrintOnClosure(outputStream* st) :
1390 _st(st) {}
1391
1392 virtual void do_thread(Thread* thread) {
1393 if (thread != nullptr) {
1394 thread->print_on(_st);
1395 _st->cr();
1396 }
1397 }
1398 };
1399
1400 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
1401 void Threads::print_on(outputStream* st, bool print_stacks,
1402 bool internal_format, bool print_concurrent_locks,
1403 bool print_extended_info) {
1404 char buf[32];
1405 st->print_raw_cr(os::local_time_string(buf, sizeof(buf)));
1406
1407 st->print_cr("Full thread dump %s (%s %s):",
1408 VM_Version::vm_name(),
1409 VM_Version::vm_release(),
1410 VM_Version::vm_info_string());
1411 st->cr();
1412
1413 #if INCLUDE_SERVICES
1414 // Dump concurrent locks
1415 ConcurrentLocksDump concurrent_locks;
1416 if (print_concurrent_locks) {
1417 concurrent_locks.dump_at_safepoint();
1418 }
1419 #endif // INCLUDE_SERVICES
1420
1421 ThreadsSMRSupport::print_info_on(st);
1422 st->cr();
1423
1424 ALL_JAVA_THREADS(p) {
1425 ResourceMark rm;
1426 p->print_on(st, print_extended_info);
1427 if (print_stacks) {
1428 if (internal_format) {
1429 p->trace_stack();
1430 } else {
1431 p->print_stack_on(st);
1432 const oop thread_oop = p->threadObj();
1433 if (thread_oop != nullptr) {
1434 if (p->is_vthread_mounted()) {
1435 const oop vt = p->vthread();
1436 assert(vt != nullptr, "vthread should not be null when vthread is mounted");
1437 // JavaThread._vthread can refer to the carrier thread. Print only if _vthread refers to a virtual thread.
1438 if (vt != thread_oop) {
1439 st->print_cr(" Mounted virtual thread #" INT64_FORMAT, (int64_t)java_lang_Thread::thread_id(vt));
1440 p->print_vthread_stack_on(st);
1441 }
1442 }
1443 }
1444 }
1445 }
1446 st->cr();
1447 #if INCLUDE_SERVICES
1448 if (print_concurrent_locks) {
1449 concurrent_locks.print_locks_on(p, st);
1450 }
1451 #endif // INCLUDE_SERVICES
1452 }
1453
1454 PrintOnClosure cl(st);
1455 non_java_threads_do(&cl);
1456
1457 st->flush();
1458 }
1459
1460 void Threads::print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
1461 int buflen, bool* found_current) {
1462 if (this_thread != nullptr) {
1463 bool is_current = (current == this_thread);
1464 *found_current = *found_current || is_current;
1465 st->print("%s", is_current ? "=>" : " ");
1466
1467 st->print(PTR_FORMAT, p2i(this_thread));
1468 st->print(" ");
1469 this_thread->print_on_error(st, buf, buflen);
1470 st->cr();
1471 }
1472 }
1473
1474 class PrintOnErrorClosure : public ThreadClosure {
1475 outputStream* _st;
1476 Thread* _current;
1477 char* _buf;
1478 int _buflen;
1479 bool* _found_current;
1480 unsigned _num_printed;
1481 public:
1482 PrintOnErrorClosure(outputStream* st, Thread* current, char* buf,
1483 int buflen, bool* found_current) :
1484 _st(st), _current(current), _buf(buf), _buflen(buflen), _found_current(found_current),
1485 _num_printed(0) {}
1486
1487 virtual void do_thread(Thread* thread) {
1488 _num_printed++;
1489 Threads::print_on_error(thread, _st, _current, _buf, _buflen, _found_current);
1490 }
1491
1492 unsigned num_printed() const { return _num_printed; }
1493 };
1494
1495 // Threads::print_on_error() is called by fatal error handler. It's possible
1496 // that VM is not at safepoint and/or current thread is inside signal handler.
1497 // Don't print stack trace, as the stack may not be walkable. Don't allocate
1498 // memory (even in resource area), it might deadlock the error handler.
1499 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
1500 int buflen) {
1501 ThreadsSMRSupport::print_info_on(st);
1502 st->cr();
1503
1504 bool found_current = false;
1505 st->print_cr("Java Threads: ( => current thread )");
1506 unsigned num_java = 0;
1507 ALL_JAVA_THREADS(thread) {
1508 print_on_error(thread, st, current, buf, buflen, &found_current);
1509 num_java++;
1510 }
1511 st->print_cr("Total: %u", num_java);
1512 st->cr();
1513
1514 st->print_cr("Other Threads:");
1515 unsigned num_other = ((VMThread::vm_thread() != nullptr) ? 1 : 0) +
1516 ((WatcherThread::watcher_thread() != nullptr) ? 1 : 0) +
1517 ((AsyncLogWriter::instance() != nullptr) ? 1 : 0);
1518 print_on_error(VMThread::vm_thread(), st, current, buf, buflen, &found_current);
1519 print_on_error(WatcherThread::watcher_thread(), st, current, buf, buflen, &found_current);
1520 print_on_error(AsyncLogWriter::instance(), st, current, buf, buflen, &found_current);
1521
1522 if (Universe::heap() != nullptr) {
1523 PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current);
1524 Universe::heap()->gc_threads_do(&print_closure);
1525 num_other += print_closure.num_printed();
1526 }
1527
1528 if (!found_current) {
1529 st->cr();
1530 st->print("=>" PTR_FORMAT " (exited) ", p2i(current));
1531 current->print_on_error(st, buf, buflen);
1532 num_other++;
1533 st->cr();
1534 }
1535 st->print_cr("Total: %u", num_other);
1536 st->cr();
1537
1538 st->print_cr("Threads with active compile tasks:");
1539 unsigned num = print_threads_compiling(st, buf, buflen);
1540 st->print_cr("Total: %u", num);
1541 }
1542
1543 unsigned Threads::print_threads_compiling(outputStream* st, char* buf, int buflen, bool short_form) {
1544 unsigned num = 0;
1545 ALL_JAVA_THREADS(thread) {
1546 if (thread->is_Compiler_thread()) {
1547 CompilerThread* ct = (CompilerThread*) thread;
1548
1549 // Keep task in local variable for null check.
1550 // ct->_task might be set to null by concurring compiler thread
1551 // because it completed the compilation. The task is never freed,
1552 // though, just returned to a free list.
1553 CompileTask* task = ct->task();
1554 if (task != nullptr) {
1555 thread->print_name_on_error(st, buf, buflen);
1556 st->print(" ");
1557 task->print(st, nullptr, short_form, true);
1558 num++;
1559 }
1560 }
1561 }
1562 return num;
1563 }
1564
1565 void Threads::verify() {
1566 ALL_JAVA_THREADS(p) {
1567 p->verify();
1568 }
1569 VMThread* thread = VMThread::vm_thread();
1570 if (thread != nullptr) thread->verify();
1571 }