1 /*
2 * Copyright (c) 1997, 2023, Oracle and/or its affiliates. All rights reserved.
3 * Copyright (c) 2021, Azul Systems, Inc. All rights reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 #include "precompiled.hpp"
27 #include "cds/cds_globals.hpp"
28 #include "cds/metaspaceShared.hpp"
29 #include "classfile/classLoader.hpp"
30 #include "classfile/javaClasses.hpp"
31 #include "classfile/javaThreadStatus.hpp"
32 #include "classfile/systemDictionary.hpp"
33 #include "classfile/vmClasses.hpp"
34 #include "classfile/vmSymbols.hpp"
35 #include "compiler/compileBroker.hpp"
36 #include "compiler/compileTask.hpp"
37 #include "compiler/compilerThread.hpp"
38 #include "gc/shared/barrierSet.hpp"
39 #include "gc/shared/barrierSetNMethod.hpp"
40 #include "gc/shared/gcVMOperations.hpp"
41 #include "gc/shared/oopStorage.hpp"
42 #include "gc/shared/oopStorageSet.hpp"
43 #include "gc/shared/stringdedup/stringDedup.hpp"
44 #include "jfr/jfrEvents.hpp"
45 #include "jvm.h"
46 #include "jvmtifiles/jvmtiEnv.hpp"
47 #include "logging/log.hpp"
48 #include "logging/logAsyncWriter.hpp"
49 #include "logging/logConfiguration.hpp"
50 #include "memory/allocation.inline.hpp"
51 #include "memory/iterator.hpp"
52 #include "memory/oopFactory.hpp"
53 #include "memory/resourceArea.hpp"
54 #include "memory/universe.hpp"
55 #include "oops/instanceKlass.hpp"
56 #include "oops/klass.inline.hpp"
57 #include "oops/oop.inline.hpp"
58 #include "oops/symbol.hpp"
59 #include "prims/jvm_misc.hpp"
60 #include "runtime/arguments.hpp"
61 #include "runtime/fieldDescriptor.inline.hpp"
62 #include "runtime/flags/jvmFlagLimit.hpp"
63 #include "runtime/handles.inline.hpp"
64 #include "runtime/globals.hpp"
65 #include "runtime/interfaceSupport.inline.hpp"
66 #include "runtime/java.hpp"
67 #include "runtime/javaCalls.hpp"
68 #include "runtime/javaThread.inline.hpp"
69 #include "runtime/jniHandles.inline.hpp"
70 #include "runtime/jniPeriodicChecker.hpp"
71 #include "runtime/lockStack.inline.hpp"
72 #include "runtime/monitorDeflationThread.hpp"
73 #include "runtime/mutexLocker.hpp"
74 #include "runtime/nonJavaThread.hpp"
75 #include "runtime/objectMonitor.inline.hpp"
76 #include "runtime/osThread.hpp"
77 #include "runtime/safepoint.hpp"
78 #include "runtime/safepointMechanism.inline.hpp"
79 #include "runtime/safepointVerifiers.hpp"
80 #include "runtime/serviceThread.hpp"
81 #include "runtime/sharedRuntime.hpp"
82 #include "runtime/statSampler.hpp"
83 #include "runtime/stubCodeGenerator.hpp"
84 #include "runtime/thread.inline.hpp"
85 #include "runtime/threads.hpp"
86 #include "runtime/threadSMR.inline.hpp"
87 #include "runtime/timer.hpp"
88 #include "runtime/timerTrace.hpp"
89 #include "runtime/vmOperations.hpp"
90 #include "runtime/vm_version.hpp"
91 #include "services/attachListener.hpp"
92 #include "services/management.hpp"
93 #include "services/memTracker.hpp"
94 #include "services/threadIdTable.hpp"
95 #include "services/threadService.hpp"
96 #include "utilities/dtrace.hpp"
97 #include "utilities/events.hpp"
98 #include "utilities/macros.hpp"
99 #include "utilities/systemMemoryBarrier.hpp"
100 #include "utilities/vmError.hpp"
101 #if INCLUDE_JVMCI
102 #include "jvmci/jvmci.hpp"
103 #include "jvmci/jvmciEnv.hpp"
104 #endif
105 #ifdef COMPILER2
106 #include "opto/idealGraphPrinter.hpp"
107 #endif
108 #if INCLUDE_RTM_OPT
109 #include "runtime/rtmLocking.hpp"
110 #endif
111 #if INCLUDE_JFR
112 #include "jfr/jfr.hpp"
113 #endif
114
115 // Initialization after module runtime initialization
116 void universe_post_module_init(); // must happen after call_initPhase2
117
118
119 static void initialize_class(Symbol* class_name, TRAPS) {
120 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
121 InstanceKlass::cast(klass)->initialize(CHECK);
122 }
123
124
125 // Creates the initial ThreadGroup
126 static Handle create_initial_thread_group(TRAPS) {
127 Handle system_instance = JavaCalls::construct_new_instance(
128 vmClasses::ThreadGroup_klass(),
129 vmSymbols::void_method_signature(),
130 CHECK_NH);
131 Universe::set_system_thread_group(system_instance());
132
133 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
134 Handle main_instance = JavaCalls::construct_new_instance(
135 vmClasses::ThreadGroup_klass(),
136 vmSymbols::threadgroup_string_void_signature(),
137 system_instance,
138 string,
139 CHECK_NH);
140 return main_instance;
141 }
142
143 // Creates the initial Thread, and sets it to running.
144 static void create_initial_thread(Handle thread_group, JavaThread* thread,
145 TRAPS) {
146 InstanceKlass* ik = vmClasses::Thread_klass();
147 assert(ik->is_initialized(), "must be");
148 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
149
150 // Cannot use JavaCalls::construct_new_instance because the java.lang.Thread
151 // constructor calls Thread.current(), which must be set here for the
152 // initial thread.
153 java_lang_Thread::set_thread(thread_oop(), thread);
154 thread->set_threadOopHandles(thread_oop());
155
156 Handle string = java_lang_String::create_from_str("main", CHECK);
157
158 JavaValue result(T_VOID);
159 JavaCalls::call_special(&result, thread_oop,
160 ik,
161 vmSymbols::object_initializer_name(),
162 vmSymbols::threadgroup_string_void_signature(),
163 thread_group,
164 string,
165 CHECK);
166
167 // Set thread status to running since main thread has
168 // been started and running.
169 java_lang_Thread::set_thread_status(thread_oop(),
170 JavaThreadStatus::RUNNABLE);
171 }
172
173 // Extract version and vendor specific information from
174 // java.lang.VersionProps fields.
175 // Returned char* is allocated in the thread's resource area
176 // so must be copied for permanency.
177 static const char* get_java_version_info(InstanceKlass* ik,
178 Symbol* field_name) {
179 fieldDescriptor fd;
180 bool found = ik != nullptr &&
181 ik->find_local_field(field_name,
182 vmSymbols::string_signature(), &fd);
183 if (found) {
184 oop name_oop = ik->java_mirror()->obj_field(fd.offset());
185 if (name_oop == nullptr) {
186 return nullptr;
187 }
188 const char* name = java_lang_String::as_utf8_string(name_oop);
189 return name;
190 } else {
191 return nullptr;
192 }
193 }
194
195 // ======= Threads ========
196
197 // The Threads class links together all active threads, and provides
198 // operations over all threads. It is protected by the Threads_lock,
199 // which is also used in other global contexts like safepointing.
200 // ThreadsListHandles are used to safely perform operations on one
201 // or more threads without the risk of the thread exiting during the
202 // operation.
203 //
204 // Note: The Threads_lock is currently more widely used than we
205 // would like. We are actively migrating Threads_lock uses to other
206 // mechanisms in order to reduce Threads_lock contention.
207
208 int Threads::_number_of_threads = 0;
209 int Threads::_number_of_non_daemon_threads = 0;
210 int Threads::_return_code = 0;
211 uintx Threads::_thread_claim_token = 1; // Never zero.
212
213 #ifdef ASSERT
214 bool Threads::_vm_complete = false;
215 #endif
216
217 // General purpose hook into Java code, run once when the VM is initialized.
218 // The Java library method itself may be changed independently from the VM.
219 static void call_postVMInitHook(TRAPS) {
220 Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_vm_PostVMInitHook(), THREAD);
221 if (klass != nullptr) {
222 JavaValue result(T_VOID);
223 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
224 vmSymbols::void_method_signature(),
225 CHECK);
226 }
227 }
228
229 // All NonJavaThreads (i.e., every non-JavaThread in the system).
230 void Threads::non_java_threads_do(ThreadClosure* tc) {
231 NoSafepointVerifier nsv;
232 for (NonJavaThread::Iterator njti; !njti.end(); njti.step()) {
233 tc->do_thread(njti.current());
234 }
235 }
236
237 // All JavaThreads
238 #define ALL_JAVA_THREADS(X) \
239 for (JavaThread* X : *ThreadsSMRSupport::get_java_thread_list())
240
241 // All JavaThreads
242 void Threads::java_threads_do(ThreadClosure* tc) {
243 assert_locked_or_safepoint(Threads_lock);
244 // ALL_JAVA_THREADS iterates through all JavaThreads.
245 ALL_JAVA_THREADS(p) {
246 tc->do_thread(p);
247 }
248 }
249
250 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system).
251 void Threads::threads_do(ThreadClosure* tc) {
252 assert_locked_or_safepoint(Threads_lock);
253 java_threads_do(tc);
254 non_java_threads_do(tc);
255 }
256
257 void Threads::possibly_parallel_threads_do(bool is_par, ThreadClosure* tc) {
258 assert_at_safepoint();
259
260 uintx claim_token = Threads::thread_claim_token();
261 ALL_JAVA_THREADS(p) {
262 if (p->claim_threads_do(is_par, claim_token)) {
263 tc->do_thread(p);
264 }
265 }
266 for (NonJavaThread::Iterator njti; !njti.end(); njti.step()) {
267 Thread* current = njti.current();
268 if (current->claim_threads_do(is_par, claim_token)) {
269 tc->do_thread(current);
270 }
271 }
272 }
273
274 // The system initialization in the library has three phases.
275 //
276 // Phase 1: java.lang.System class initialization
277 // java.lang.System is a primordial class loaded and initialized
278 // by the VM early during startup. java.lang.System.<clinit>
279 // only does registerNatives and keeps the rest of the class
280 // initialization work later until thread initialization completes.
281 //
282 // System.initPhase1 initializes the system properties, the static
283 // fields in, out, and err. Set up java signal handlers, OS-specific
284 // system settings, and thread group of the main thread.
285 static void call_initPhase1(TRAPS) {
286 Klass* klass = vmClasses::System_klass();
287 JavaValue result(T_VOID);
288 JavaCalls::call_static(&result, klass, vmSymbols::initPhase1_name(),
289 vmSymbols::void_method_signature(), CHECK);
290 }
291
292 // Phase 2. Module system initialization
293 // This will initialize the module system. Only java.base classes
294 // can be loaded until phase 2 completes.
295 //
296 // Call System.initPhase2 after the compiler initialization and jsr292
297 // classes get initialized because module initialization runs a lot of java
298 // code, that for performance reasons, should be compiled. Also, this will
299 // enable the startup code to use lambda and other language features in this
300 // phase and onward.
301 //
302 // After phase 2, The VM will begin search classes from -Xbootclasspath/a.
303 static void call_initPhase2(TRAPS) {
304 TraceTime timer("Initialize module system", TRACETIME_LOG(Info, startuptime));
305
306 Klass* klass = vmClasses::System_klass();
307
308 JavaValue result(T_INT);
309 JavaCallArguments args;
310 args.push_int(DisplayVMOutputToStderr);
311 args.push_int(log_is_enabled(Debug, init)); // print stack trace if exception thrown
312 JavaCalls::call_static(&result, klass, vmSymbols::initPhase2_name(),
313 vmSymbols::boolean_boolean_int_signature(), &args, CHECK);
314 if (result.get_jint() != JNI_OK) {
315 vm_exit_during_initialization(); // no message or exception
316 }
317
318 universe_post_module_init();
319 }
320
321 // Phase 3. final setup - set security manager, system class loader and TCCL
322 //
323 // This will instantiate and set the security manager, set the system class
324 // loader as well as the thread context class loader. The security manager
325 // and system class loader may be a custom class loaded from -Xbootclasspath/a,
326 // other modules or the application's classpath.
327 static void call_initPhase3(TRAPS) {
328 Klass* klass = vmClasses::System_klass();
329 JavaValue result(T_VOID);
330 JavaCalls::call_static(&result, klass, vmSymbols::initPhase3_name(),
331 vmSymbols::void_method_signature(), CHECK);
332 }
333
334 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
335 TraceTime timer("Initialize java.lang classes", TRACETIME_LOG(Info, startuptime));
336
337 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
338 create_vm_init_libraries();
339 }
340
341 initialize_class(vmSymbols::java_lang_String(), CHECK);
342
343 // Inject CompactStrings value after the static initializers for String ran.
344 java_lang_String::set_compact_strings(CompactStrings);
345
346 // Initialize java_lang.System (needed before creating the thread)
347 initialize_class(vmSymbols::java_lang_System(), CHECK);
348 // The VM creates & returns objects of this class. Make sure it's initialized.
349 initialize_class(vmSymbols::java_lang_Class(), CHECK);
350 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
351 Handle thread_group = create_initial_thread_group(CHECK);
352 Universe::set_main_thread_group(thread_group());
353 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
354 create_initial_thread(thread_group, main_thread, CHECK);
355
356 // The VM creates objects of this class.
357 initialize_class(vmSymbols::java_lang_Module(), CHECK);
358
359 #ifdef ASSERT
360 InstanceKlass *k = vmClasses::UnsafeConstants_klass();
361 assert(k->is_not_initialized(), "UnsafeConstants should not already be initialized");
362 #endif
363
364 // initialize the hardware-specific constants needed by Unsafe
365 initialize_class(vmSymbols::jdk_internal_misc_UnsafeConstants(), CHECK);
366 jdk_internal_misc_UnsafeConstants::set_unsafe_constants();
367
368 // The VM preresolves methods to these classes. Make sure that they get initialized
369 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
370 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
371
372 // Phase 1 of the system initialization in the library, java.lang.System class initialization
373 call_initPhase1(CHECK);
374
375 // Get the Java runtime name, version, and vendor info after java.lang.System is initialized.
376 // Some values are actually configure-time constants but some can be set via the jlink tool and
377 // so must be read dynamically. We treat them all the same.
378 InstanceKlass* ik = SystemDictionary::find_instance_klass(THREAD, vmSymbols::java_lang_VersionProps(),
379 Handle(), Handle());
380 {
381 ResourceMark rm(main_thread);
382 JDK_Version::set_java_version(get_java_version_info(ik, vmSymbols::java_version_name()));
383
384 JDK_Version::set_runtime_name(get_java_version_info(ik, vmSymbols::java_runtime_name_name()));
385
386 JDK_Version::set_runtime_version(get_java_version_info(ik, vmSymbols::java_runtime_version_name()));
387
388 JDK_Version::set_runtime_vendor_version(get_java_version_info(ik, vmSymbols::java_runtime_vendor_version_name()));
389
390 JDK_Version::set_runtime_vendor_vm_bug_url(get_java_version_info(ik, vmSymbols::java_runtime_vendor_vm_bug_url_name()));
391 }
392
393 // an instance of OutOfMemory exception has been allocated earlier
394 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
395 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
396 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
397 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
398 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
399 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
400 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
401 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
402 }
403
404 void Threads::initialize_jsr292_core_classes(TRAPS) {
405 TraceTime timer("Initialize java.lang.invoke classes", TRACETIME_LOG(Info, startuptime));
406
407 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
408 initialize_class(vmSymbols::java_lang_invoke_ResolvedMethodName(), CHECK);
409 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
410 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
411 }
412
413 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
414 extern void JDK_Version_init();
415
416 // Preinitialize version info.
417 VM_Version::early_initialize();
418
419 // Check version
420 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
421
422 // Initialize library-based TLS
423 ThreadLocalStorage::init();
424
425 // Initialize the output stream module
426 ostream_init();
427
428 // Process java launcher properties.
429 Arguments::process_sun_java_launcher_properties(args);
430
431 // Initialize the os module
432 os::init();
433
434 MACOS_AARCH64_ONLY(os::current_thread_enable_wx(WXWrite));
435
436 // Record VM creation timing statistics
437 TraceVmCreationTime create_vm_timer;
438 create_vm_timer.start();
439
440 // Initialize system properties.
441 Arguments::init_system_properties();
442
443 // So that JDK version can be used as a discriminator when parsing arguments
444 JDK_Version_init();
445
446 // Update/Initialize System properties after JDK version number is known
447 Arguments::init_version_specific_system_properties();
448
449 // Make sure to initialize log configuration *before* parsing arguments
450 LogConfiguration::initialize(create_vm_timer.begin_time());
451
452 // Parse arguments
453 // Note: this internally calls os::init_container_support()
454 jint parse_result = Arguments::parse(args);
455 if (parse_result != JNI_OK) return parse_result;
456
457 // Initialize NMT right after argument parsing to keep the pre-NMT-init window small.
458 MemTracker::initialize();
459
460 os::init_before_ergo();
461
462 jint ergo_result = Arguments::apply_ergo();
463 if (ergo_result != JNI_OK) return ergo_result;
464
465 // Final check of all ranges after ergonomics which may change values.
466 if (!JVMFlagLimit::check_all_ranges()) {
467 return JNI_EINVAL;
468 }
469
470 // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
471 bool constraint_result = JVMFlagLimit::check_all_constraints(JVMFlagConstraintPhase::AfterErgo);
472 if (!constraint_result) {
473 return JNI_EINVAL;
474 }
475
476 if (PauseAtStartup) {
477 os::pause();
478 }
479
480 HOTSPOT_VM_INIT_BEGIN();
481
482 // Timing (must come after argument parsing)
483 TraceTime timer("Create VM", TRACETIME_LOG(Info, startuptime));
484
485 // Initialize the os module after parsing the args
486 jint os_init_2_result = os::init_2();
487 if (os_init_2_result != JNI_OK) return os_init_2_result;
488
489 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT
490 // Initialize assert poison page mechanism.
491 if (ShowRegistersOnAssert) {
492 initialize_assert_poison();
493 }
494 #endif // CAN_SHOW_REGISTERS_ON_ASSERT
495
496 SafepointMechanism::initialize();
497
498 jint adjust_after_os_result = Arguments::adjust_after_os();
499 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
500
501 // Initialize output stream logging
502 ostream_init_log();
503
504 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
505 // Must be before create_vm_init_agents()
506 if (Arguments::init_libraries_at_startup()) {
507 convert_vm_init_libraries_to_agents();
508 }
509
510 // Launch -agentlib/-agentpath and converted -Xrun agents
511 if (Arguments::init_agents_at_startup()) {
512 create_vm_init_agents();
513 }
514
515 // Initialize Threads state
516 _number_of_threads = 0;
517 _number_of_non_daemon_threads = 0;
518
519 // Initialize global data structures and create system classes in heap
520 vm_init_globals();
521
522 #if INCLUDE_JVMCI
523 if (JVMCICounterSize > 0) {
524 JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtJVMCI);
525 memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize);
526 } else {
527 JavaThread::_jvmci_old_thread_counters = nullptr;
528 }
529 #endif // INCLUDE_JVMCI
530
531 // Initialize OopStorage for threadObj
532 JavaThread::_thread_oop_storage = OopStorageSet::create_strong("Thread OopStorage", mtThread);
533
534 // Attach the main thread to this os thread
535 JavaThread* main_thread = new JavaThread();
536 main_thread->set_thread_state(_thread_in_vm);
537 main_thread->initialize_thread_current();
538 // must do this before set_active_handles
539 main_thread->record_stack_base_and_size();
540 main_thread->register_thread_stack_with_NMT();
541 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
542 MACOS_AARCH64_ONLY(main_thread->init_wx());
543
544 if (!main_thread->set_as_starting_thread()) {
545 vm_shutdown_during_initialization(
546 "Failed necessary internal allocation. Out of swap space");
547 main_thread->smr_delete();
548 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
549 return JNI_ENOMEM;
550 }
551
552 // Enable guard page *after* os::create_main_thread(), otherwise it would
553 // crash Linux VM, see notes in os_linux.cpp.
554 main_thread->stack_overflow_state()->create_stack_guard_pages();
555
556 if (UseSystemMemoryBarrier) {
557 if (!SystemMemoryBarrier::initialize()) {
558 vm_shutdown_during_initialization("Failed to initialize the requested system memory barrier synchronization.");
559 return JNI_EINVAL;
560 }
561 log_debug(os)("Using experimental system memory barrier synchronization");
562 }
563
564 // Initialize Java-Level synchronization subsystem
565 ObjectMonitor::Initialize();
566 ObjectSynchronizer::initialize();
567
568 // Initialize global modules
569 jint status = init_globals();
570 if (status != JNI_OK) {
571 main_thread->smr_delete();
572 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
573 return status;
574 }
575
576 JFR_ONLY(Jfr::on_create_vm_1();)
577
578 // Should be done after the heap is fully created
579 main_thread->cache_global_variables();
580
581 { MutexLocker mu(Threads_lock);
582 Threads::add(main_thread);
583 }
584
585 // Any JVMTI raw monitors entered in onload will transition into
586 // real raw monitor. VM is setup enough here for raw monitor enter.
587 JvmtiExport::transition_pending_onload_raw_monitors();
588
589 // Create the VMThread
590 { TraceTime timer("Start VMThread", TRACETIME_LOG(Info, startuptime));
591
592 VMThread::create();
593 VMThread* vmthread = VMThread::vm_thread();
594
595 if (!os::create_thread(vmthread, os::vm_thread)) {
596 vm_exit_during_initialization("Cannot create VM thread. "
597 "Out of system resources.");
598 }
599
600 // Wait for the VM thread to become ready, and VMThread::run to initialize
601 // Monitors can have spurious returns, must always check another state flag
602 {
603 MonitorLocker ml(Notify_lock);
604 os::start_thread(vmthread);
605 while (!vmthread->is_running()) {
606 ml.wait();
607 }
608 }
609 }
610
611 assert(Universe::is_fully_initialized(), "not initialized");
612 if (VerifyDuringStartup) {
613 // Make sure we're starting with a clean slate.
614 VM_Verify verify_op;
615 VMThread::execute(&verify_op);
616 }
617
618 // We need this to update the java.vm.info property in case any flags used
619 // to initially define it have been changed. This is needed for both CDS
620 // since UseSharedSpaces may be changed after java.vm.info
621 // is initially computed. See Abstract_VM_Version::vm_info_string().
622 // This update must happen before we initialize the java classes, but
623 // after any initialization logic that might modify the flags.
624 Arguments::update_vm_info_property(VM_Version::vm_info_string());
625
626 JavaThread* THREAD = JavaThread::current(); // For exception macros.
627 HandleMark hm(THREAD);
628
629 // Always call even when there are not JVMTI environments yet, since environments
630 // may be attached late and JVMTI must track phases of VM execution
631 JvmtiExport::enter_early_start_phase();
632
633 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
634 JvmtiExport::post_early_vm_start();
635
636 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
637
638 quicken_jni_functions();
639
640 // No more stub generation allowed after that point.
641 StubCodeDesc::freeze();
642
643 // Set flag that basic initialization has completed. Used by exceptions and various
644 // debug stuff, that does not work until all basic classes have been initialized.
645 set_init_completed();
646
647 LogConfiguration::post_initialize();
648 Metaspace::post_initialize();
649 MutexLocker::post_initialize();
650
651 HOTSPOT_VM_INIT_END();
652
653 // record VM initialization completion time
654 #if INCLUDE_MANAGEMENT
655 Management::record_vm_init_completed();
656 #endif // INCLUDE_MANAGEMENT
657
658 // Signal Dispatcher needs to be started before VMInit event is posted
659 os::initialize_jdk_signal_support(CHECK_JNI_ERR);
660
661 // Start Attach Listener if +StartAttachListener or it can't be started lazily
662 if (!DisableAttachMechanism) {
663 AttachListener::vm_start();
664 if (StartAttachListener || AttachListener::init_at_startup()) {
665 AttachListener::init();
666 }
667 }
668
669 // Launch -Xrun agents
670 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
671 // back-end can launch with -Xdebug -Xrunjdwp.
672 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
673 create_vm_init_libraries();
674 }
675
676 Chunk::start_chunk_pool_cleaner_task();
677
678 // Start the service thread
679 // The service thread enqueues JVMTI deferred events and does various hashtable
680 // and other cleanups. Needs to start before the compilers start posting events.
681 ServiceThread::initialize();
682
683 // Start the monitor deflation thread:
684 MonitorDeflationThread::initialize();
685
686 // initialize compiler(s)
687 #if defined(COMPILER1) || COMPILER2_OR_JVMCI
688 #if INCLUDE_JVMCI
689 bool force_JVMCI_intialization = false;
690 if (EnableJVMCI) {
691 // Initialize JVMCI eagerly when it is explicitly requested.
692 // Or when JVMCILibDumpJNIConfig or JVMCIPrintProperties is enabled.
693 force_JVMCI_intialization = EagerJVMCI || JVMCIPrintProperties || JVMCILibDumpJNIConfig;
694
695 if (!force_JVMCI_intialization) {
696 // 8145270: Force initialization of JVMCI runtime otherwise requests for blocking
697 // compilations via JVMCI will not actually block until JVMCI is initialized.
698 force_JVMCI_intialization = UseJVMCICompiler && (!UseInterpreter || !BackgroundCompilation);
699 }
700 }
701 #endif
702 CompileBroker::compilation_init_phase1(CHECK_JNI_ERR);
703 // Postpone completion of compiler initialization to after JVMCI
704 // is initialized to avoid timeouts of blocking compilations.
705 if (JVMCI_ONLY(!force_JVMCI_intialization) NOT_JVMCI(true)) {
706 CompileBroker::compilation_init_phase2();
707 }
708 #endif
709
710 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
711 // It is done after compilers are initialized, because otherwise compilations of
712 // signature polymorphic MH intrinsics can be missed
713 // (see SystemDictionary::find_method_handle_intrinsic).
714 initialize_jsr292_core_classes(CHECK_JNI_ERR);
715
716 // This will initialize the module system. Only java.base classes can be
717 // loaded until phase 2 completes
718 call_initPhase2(CHECK_JNI_ERR);
719
720 JFR_ONLY(Jfr::on_create_vm_2();)
721
722 // Always call even when there are not JVMTI environments yet, since environments
723 // may be attached late and JVMTI must track phases of VM execution
724 JvmtiExport::enter_start_phase();
725
726 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
727 JvmtiExport::post_vm_start();
728
729 // Final system initialization including security manager and system class loader
730 call_initPhase3(CHECK_JNI_ERR);
731
732 // cache the system and platform class loaders
733 SystemDictionary::compute_java_loaders(CHECK_JNI_ERR);
734
735 #if INCLUDE_CDS
736 // capture the module path info from the ModuleEntryTable
737 ClassLoader::initialize_module_path(THREAD);
738 if (HAS_PENDING_EXCEPTION) {
739 java_lang_Throwable::print(PENDING_EXCEPTION, tty);
740 vm_exit_during_initialization("ClassLoader::initialize_module_path() failed unexpectedly");
741 }
742 #endif
743
744 #if INCLUDE_JVMCI
745 if (force_JVMCI_intialization) {
746 JVMCI::initialize_compiler(CHECK_JNI_ERR);
747 CompileBroker::compilation_init_phase2();
748 }
749 #endif
750
751 // Always call even when there are not JVMTI environments yet, since environments
752 // may be attached late and JVMTI must track phases of VM execution
753 JvmtiExport::enter_live_phase();
754
755 // Make perfmemory accessible
756 PerfMemory::set_accessible(true);
757
758 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
759 JvmtiExport::post_vm_initialized();
760
761 JFR_ONLY(Jfr::on_create_vm_3();)
762
763 #if INCLUDE_MANAGEMENT
764 Management::initialize(THREAD);
765
766 if (HAS_PENDING_EXCEPTION) {
767 // management agent fails to start possibly due to
768 // configuration problem and is responsible for printing
769 // stack trace if appropriate. Simply exit VM.
770 vm_exit(1);
771 }
772 #endif // INCLUDE_MANAGEMENT
773
774 StatSampler::engage();
775 if (CheckJNICalls) JniPeriodicChecker::engage();
776
777 #if INCLUDE_RTM_OPT
778 RTMLockingCounters::init();
779 #endif
780
781 call_postVMInitHook(THREAD);
782 // The Java side of PostVMInitHook.run must deal with all
783 // exceptions and provide means of diagnosis.
784 if (HAS_PENDING_EXCEPTION) {
785 CLEAR_PENDING_EXCEPTION;
786 }
787
788 {
789 MutexLocker ml(PeriodicTask_lock);
790 // Make sure the WatcherThread can be started by WatcherThread::start()
791 // or by dynamic enrollment.
792 WatcherThread::make_startable();
793 // Start up the WatcherThread if there are any periodic tasks
794 // NOTE: All PeriodicTasks should be registered by now. If they
795 // aren't, late joiners might appear to start slowly (we might
796 // take a while to process their first tick).
797 if (PeriodicTask::num_tasks() > 0) {
798 WatcherThread::start();
799 }
800 }
801
802 create_vm_timer.end();
803 #ifdef ASSERT
804 _vm_complete = true;
805 #endif
806
807 if (DumpSharedSpaces) {
808 MetaspaceShared::preload_and_dump();
809 ShouldNotReachHere();
810 }
811
812 return JNI_OK;
813 }
814
815 // type for the Agent_OnLoad and JVM_OnLoad entry points
816 extern "C" {
817 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
818 }
819 // Find a command line agent library and return its entry point for
820 // -agentlib: -agentpath: -Xrun
821 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
822 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
823 const char *on_load_symbols[],
824 size_t num_symbol_entries) {
825 OnLoadEntry_t on_load_entry = nullptr;
826 void *library = nullptr;
827
828 if (!agent->valid()) {
829 char buffer[JVM_MAXPATHLEN];
830 char ebuf[1024] = "";
831 const char *name = agent->name();
832 const char *msg = "Could not find agent library ";
833
834 // First check to see if agent is statically linked into executable
835 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
836 library = agent->os_lib();
837 } else if (agent->is_absolute_path()) {
838 library = os::dll_load(name, ebuf, sizeof ebuf);
839 if (library == nullptr) {
840 const char *sub_msg = " in absolute path, with error: ";
841 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
842 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
843 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
844 // If we can't find the agent, exit.
845 vm_exit_during_initialization(buf, nullptr);
846 FREE_C_HEAP_ARRAY(char, buf);
847 }
848 } else {
849 // Try to load the agent from the standard dll directory
850 if (os::dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(),
851 name)) {
852 library = os::dll_load(buffer, ebuf, sizeof ebuf);
853 }
854 if (library == nullptr) { // Try the library path directory.
855 if (os::dll_build_name(buffer, sizeof(buffer), name)) {
856 library = os::dll_load(buffer, ebuf, sizeof ebuf);
857 }
858 if (library == nullptr) {
859 const char *sub_msg = " on the library path, with error: ";
860 const char *sub_msg2 = "\nModule java.instrument may be missing from runtime image.";
861
862 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) +
863 strlen(ebuf) + strlen(sub_msg2) + 1;
864 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
865 if (!agent->is_instrument_lib()) {
866 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
867 } else {
868 jio_snprintf(buf, len, "%s%s%s%s%s", msg, name, sub_msg, ebuf, sub_msg2);
869 }
870 // If we can't find the agent, exit.
871 vm_exit_during_initialization(buf, nullptr);
872 FREE_C_HEAP_ARRAY(char, buf);
873 }
874 }
875 }
876 agent->set_os_lib(library);
877 agent->set_valid();
878 }
879
880 // Find the OnLoad function.
881 on_load_entry =
882 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
883 false,
884 on_load_symbols,
885 num_symbol_entries));
886 return on_load_entry;
887 }
888
889 // Find the JVM_OnLoad entry point
890 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
891 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
892 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
893 }
894
895 // Find the Agent_OnLoad entry point
896 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
897 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
898 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
899 }
900
901 // For backwards compatibility with -Xrun
902 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
903 // treated like -agentpath:
904 // Must be called before agent libraries are created
905 void Threads::convert_vm_init_libraries_to_agents() {
906 AgentLibrary* agent;
907 AgentLibrary* next;
908
909 for (agent = Arguments::libraries(); agent != nullptr; agent = next) {
910 next = agent->next(); // cache the next agent now as this agent may get moved off this list
911 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
912
913 // If there is an JVM_OnLoad function it will get called later,
914 // otherwise see if there is an Agent_OnLoad
915 if (on_load_entry == nullptr) {
916 on_load_entry = lookup_agent_on_load(agent);
917 if (on_load_entry != nullptr) {
918 // switch it to the agent list -- so that Agent_OnLoad will be called,
919 // JVM_OnLoad won't be attempted and Agent_OnUnload will
920 Arguments::convert_library_to_agent(agent);
921 } else {
922 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
923 }
924 }
925 }
926 }
927
928 // Create agents for -agentlib: -agentpath: and converted -Xrun
929 // Invokes Agent_OnLoad
930 // Called very early -- before JavaThreads exist
931 void Threads::create_vm_init_agents() {
932 extern struct JavaVM_ main_vm;
933 AgentLibrary* agent;
934
935 JvmtiExport::enter_onload_phase();
936
937 for (agent = Arguments::agents(); agent != nullptr; agent = agent->next()) {
938 // CDS dumping does not support native JVMTI agent.
939 // CDS dumping supports Java agent if the AllowArchivingWithJavaAgent diagnostic option is specified.
940 if (Arguments::is_dumping_archive()) {
941 if(!agent->is_instrument_lib()) {
942 vm_exit_during_cds_dumping("CDS dumping does not support native JVMTI agent, name", agent->name());
943 } else if (!AllowArchivingWithJavaAgent) {
944 vm_exit_during_cds_dumping(
945 "Must enable AllowArchivingWithJavaAgent in order to run Java agent during CDS dumping");
946 }
947 }
948
949 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
950
951 if (on_load_entry != nullptr) {
952 // Invoke the Agent_OnLoad function
953 jint err = (*on_load_entry)(&main_vm, agent->options(), nullptr);
954 if (err != JNI_OK) {
955 vm_exit_during_initialization("agent library failed to init", agent->name());
956 }
957 } else {
958 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
959 }
960 }
961
962 JvmtiExport::enter_primordial_phase();
963 }
964
965 extern "C" {
966 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
967 }
968
969 void Threads::shutdown_vm_agents() {
970 // Send any Agent_OnUnload notifications
971 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
972 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
973 extern struct JavaVM_ main_vm;
974 for (AgentLibrary* agent = Arguments::agents(); agent != nullptr; agent = agent->next()) {
975
976 // Find the Agent_OnUnload function.
977 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
978 os::find_agent_function(agent,
979 false,
980 on_unload_symbols,
981 num_symbol_entries));
982
983 // Invoke the Agent_OnUnload function
984 if (unload_entry != nullptr) {
985 JavaThread* thread = JavaThread::current();
986 ThreadToNativeFromVM ttn(thread);
987 HandleMark hm(thread);
988 (*unload_entry)(&main_vm);
989 }
990 }
991 }
992
993 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
994 // Invokes JVM_OnLoad
995 void Threads::create_vm_init_libraries() {
996 extern struct JavaVM_ main_vm;
997 AgentLibrary* agent;
998
999 for (agent = Arguments::libraries(); agent != nullptr; agent = agent->next()) {
1000 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
1001
1002 if (on_load_entry != nullptr) {
1003 // Invoke the JVM_OnLoad function
1004 JavaThread* thread = JavaThread::current();
1005 ThreadToNativeFromVM ttn(thread);
1006 HandleMark hm(thread);
1007 jint err = (*on_load_entry)(&main_vm, agent->options(), nullptr);
1008 if (err != JNI_OK) {
1009 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
1010 }
1011 } else {
1012 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
1013 }
1014 }
1015 }
1016
1017 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
1018 // the program falls off the end of main(). Another VM exit path is through
1019 // vm_exit() when the program calls System.exit() to return a value or when
1020 // there is a serious error in VM. The two shutdown paths are not exactly
1021 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
1022 // and VM_Exit op at VM level.
1023 //
1024 // Shutdown sequence:
1025 // + Shutdown native memory tracking if it is on
1026 // + Wait until we are the last non-daemon thread to execute
1027 // <-- every thing is still working at this moment -->
1028 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
1029 // shutdown hooks
1030 // + Call before_exit(), prepare for VM exit
1031 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
1032 // currently the only user of this mechanism is File.deleteOnExit())
1033 // > stop StatSampler, watcher thread,
1034 // post thread end and vm death events to JVMTI,
1035 // stop signal thread
1036 // + Call JavaThread::exit(), it will:
1037 // > release JNI handle blocks, remove stack guard pages
1038 // > remove this thread from Threads list
1039 // <-- no more Java code from this thread after this point -->
1040 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
1041 // the compiler threads at safepoint
1042 // <-- do not use anything that could get blocked by Safepoint -->
1043 // + Disable tracing at JNI/JVM barriers
1044 // + Set _vm_exited flag for threads that are still running native code
1045 // + Call exit_globals()
1046 // > deletes tty
1047 // > deletes PerfMemory resources
1048 // + Delete this thread
1049 // + Return to caller
1050
1051 void Threads::destroy_vm() {
1052 JavaThread* thread = JavaThread::current();
1053
1054 #ifdef ASSERT
1055 _vm_complete = false;
1056 #endif
1057 // Wait until we are the last non-daemon thread to execute, or
1058 // if we are a daemon then wait until the last non-daemon thread has
1059 // executed.
1060 bool daemon = java_lang_Thread::is_daemon(thread->threadObj());
1061 int expected = daemon ? 0 : 1;
1062 {
1063 MonitorLocker nu(Threads_lock);
1064 while (Threads::number_of_non_daemon_threads() > expected)
1065 // This wait should make safepoint checks, wait without a timeout.
1066 nu.wait(0);
1067 }
1068
1069 EventShutdown e;
1070 if (e.should_commit()) {
1071 e.set_reason("No remaining non-daemon Java threads");
1072 e.commit();
1073 }
1074
1075 // Hang forever on exit if we are reporting an error.
1076 if (ShowMessageBoxOnError && VMError::is_error_reported()) {
1077 os::infinite_sleep();
1078 }
1079 os::wait_for_keypress_at_exit();
1080
1081 // run Java level shutdown hooks
1082 thread->invoke_shutdown_hooks();
1083
1084 before_exit(thread);
1085
1086 thread->exit(true);
1087
1088 // We are no longer on the main thread list but could still be in a
1089 // secondary list where another thread may try to interact with us.
1090 // So wait until all such interactions are complete before we bring
1091 // the VM to the termination safepoint. Normally this would be done
1092 // using thread->smr_delete() below where we delete the thread, but
1093 // we can't call that after the termination safepoint is active as
1094 // we will deadlock on the Threads_lock. Once all interactions are
1095 // complete it is safe to directly delete the thread at any time.
1096 ThreadsSMRSupport::wait_until_not_protected(thread);
1097
1098 // Stop VM thread.
1099 {
1100 // 4945125 The vm thread comes to a safepoint during exit.
1101 // GC vm_operations can get caught at the safepoint, and the
1102 // heap is unparseable if they are caught. Grab the Heap_lock
1103 // to prevent this. The GC vm_operations will not be able to
1104 // queue until after the vm thread is dead. After this point,
1105 // we'll never emerge out of the safepoint before the VM exits.
1106 // Assert that the thread is terminated so that acquiring the
1107 // Heap_lock doesn't cause the terminated thread to participate in
1108 // the safepoint protocol.
1109
1110 assert(thread->is_terminated(), "must be terminated here");
1111 MutexLocker ml(Heap_lock);
1112
1113 VMThread::wait_for_vm_thread_exit();
1114 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
1115 VMThread::destroy();
1116 }
1117
1118 // Now, all Java threads are gone except daemon threads. Daemon threads
1119 // running Java code or in VM are stopped by the Safepoint. However,
1120 // daemon threads executing native code are still running. But they
1121 // will be stopped at native=>Java/VM barriers. Note that we can't
1122 // simply kill or suspend them, as it is inherently deadlock-prone.
1123
1124 VM_Exit::set_vm_exited();
1125
1126 // Clean up ideal graph printers after the VMThread has started
1127 // the final safepoint which will block all the Compiler threads.
1128 // Note that this Thread has already logically exited so the
1129 // clean_up() function's use of a JavaThreadIteratorWithHandle
1130 // would be a problem except set_vm_exited() has remembered the
1131 // shutdown thread which is granted a policy exception.
1132 #if defined(COMPILER2) && !defined(PRODUCT)
1133 IdealGraphPrinter::clean_up();
1134 #endif
1135
1136 notify_vm_shutdown();
1137
1138 // exit_globals() will delete tty
1139 exit_globals();
1140
1141 // Deleting the shutdown thread here is safe. See comment on
1142 // wait_until_not_protected() above.
1143 delete thread;
1144
1145 #if INCLUDE_JVMCI
1146 if (JVMCICounterSize > 0) {
1147 FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters);
1148 }
1149 #endif
1150
1151 LogConfiguration::finalize();
1152 }
1153
1154
1155 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
1156 if (version == JNI_VERSION_1_1) return JNI_TRUE;
1157 return is_supported_jni_version(version);
1158 }
1159
1160
1161 jboolean Threads::is_supported_jni_version(jint version) {
1162 if (version == JNI_VERSION_1_2) return JNI_TRUE;
1163 if (version == JNI_VERSION_1_4) return JNI_TRUE;
1164 if (version == JNI_VERSION_1_6) return JNI_TRUE;
1165 if (version == JNI_VERSION_1_8) return JNI_TRUE;
1166 if (version == JNI_VERSION_9) return JNI_TRUE;
1167 if (version == JNI_VERSION_10) return JNI_TRUE;
1168 if (version == JNI_VERSION_19) return JNI_TRUE;
1169 if (version == JNI_VERSION_20) return JNI_TRUE;
1170 return JNI_FALSE;
1171 }
1172
1173 void Threads::add(JavaThread* p, bool force_daemon) {
1174 // The threads lock must be owned at this point
1175 assert(Threads_lock->owned_by_self(), "must have threads lock");
1176
1177 BarrierSet::barrier_set()->on_thread_attach(p);
1178
1179 // Once a JavaThread is added to the Threads list, smr_delete() has
1180 // to be used to delete it. Otherwise we can just delete it directly.
1181 p->set_on_thread_list();
1182
1183 _number_of_threads++;
1184 oop threadObj = p->threadObj();
1185 bool daemon = true;
1186 // Bootstrapping problem: threadObj can be null for initial
1187 // JavaThread (or for threads attached via JNI)
1188 if (!force_daemon &&
1189 (threadObj == nullptr || !java_lang_Thread::is_daemon(threadObj))) {
1190 _number_of_non_daemon_threads++;
1191 daemon = false;
1192 }
1193
1194 ThreadService::add_thread(p, daemon);
1195
1196 // Maintain fast thread list
1197 ThreadsSMRSupport::add_thread(p);
1198
1199 // Increase the ObjectMonitor ceiling for the new thread.
1200 ObjectSynchronizer::inc_in_use_list_ceiling();
1201
1202 // Possible GC point.
1203 Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p));
1204
1205 // Make new thread known to active EscapeBarrier
1206 EscapeBarrier::thread_added(p);
1207 }
1208
1209 void Threads::remove(JavaThread* p, bool is_daemon) {
1210 // Extra scope needed for Thread_lock, so we can check
1211 // that we do not remove thread without safepoint code notice
1212 { MonitorLocker ml(Threads_lock);
1213
1214 if (ThreadIdTable::is_initialized()) {
1215 // This cleanup must be done before the current thread's GC barrier
1216 // is detached since we need to touch the threadObj oop.
1217 jlong tid = SharedRuntime::get_java_tid(p);
1218 ThreadIdTable::remove_thread(tid);
1219 }
1220
1221 // BarrierSet state must be destroyed after the last thread transition
1222 // before the thread terminates. Thread transitions result in calls to
1223 // StackWatermarkSet::on_safepoint(), which performs GC processing,
1224 // requiring the GC state to be alive.
1225 BarrierSet::barrier_set()->on_thread_detach(p);
1226 if (p->is_exiting()) {
1227 // If we got here via JavaThread::exit(), then we remember that the
1228 // thread's GC barrier has been detached. We don't do this when we get
1229 // here from another path, e.g., cleanup_failed_attach_current_thread().
1230 p->set_terminated(JavaThread::_thread_gc_barrier_detached);
1231 }
1232
1233 assert(ThreadsSMRSupport::get_java_thread_list()->includes(p), "p must be present");
1234
1235 // Maintain fast thread list
1236 ThreadsSMRSupport::remove_thread(p);
1237
1238 _number_of_threads--;
1239 if (!is_daemon) {
1240 _number_of_non_daemon_threads--;
1241
1242 // If this is the last non-daemon thread then we need to do
1243 // a notify on the Threads_lock so a thread waiting
1244 // on destroy_vm will wake up. But that thread could be a daemon
1245 // or non-daemon, so we notify for both the 0 and 1 case.
1246 if (number_of_non_daemon_threads() <= 1) {
1247 ml.notify_all();
1248 }
1249 }
1250 ThreadService::remove_thread(p, is_daemon);
1251
1252 // Make sure that safepoint code disregard this thread. This is needed since
1253 // the thread might mess around with locks after this point. This can cause it
1254 // to do callbacks into the safepoint code. However, the safepoint code is not aware
1255 // of this thread since it is removed from the queue.
1256 p->set_terminated(JavaThread::_thread_terminated);
1257
1258 // Notify threads waiting in EscapeBarriers
1259 EscapeBarrier::thread_removed(p);
1260 } // unlock Threads_lock
1261
1262 // Reduce the ObjectMonitor ceiling for the exiting thread.
1263 ObjectSynchronizer::dec_in_use_list_ceiling();
1264
1265 // Since Events::log uses a lock, we grab it outside the Threads_lock
1266 Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p));
1267 }
1268
1269 // Operations on the Threads list for GC. These are not explicitly locked,
1270 // but the garbage collector must provide a safe context for them to run.
1271 // In particular, these things should never be called when the Threads_lock
1272 // is held by some other thread. (Note: the Safepoint abstraction also
1273 // uses the Threads_lock to guarantee this property. It also makes sure that
1274 // all threads gets blocked when exiting or starting).
1275
1276 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) {
1277 ALL_JAVA_THREADS(p) {
1278 p->oops_do(f, cf);
1279 }
1280 VMThread::vm_thread()->oops_do(f, cf);
1281 }
1282
1283 void Threads::change_thread_claim_token() {
1284 if (++_thread_claim_token == 0) {
1285 // On overflow of the token counter, there is a risk of future
1286 // collisions between a new global token value and a stale token
1287 // for a thread, because not all iterations visit all threads.
1288 // (Though it's pretty much a theoretical concern for non-trivial
1289 // token counter sizes.) To deal with the possibility, reset all
1290 // the thread tokens to zero on global token overflow.
1291 struct ResetClaims : public ThreadClosure {
1292 virtual void do_thread(Thread* t) {
1293 t->claim_threads_do(false, 0);
1294 }
1295 } reset_claims;
1296 Threads::threads_do(&reset_claims);
1297 // On overflow, update the global token to non-zero, to
1298 // avoid the special "never claimed" initial thread value.
1299 _thread_claim_token = 1;
1300 }
1301 }
1302
1303 #ifdef ASSERT
1304 void assert_thread_claimed(const char* kind, Thread* t, uintx expected) {
1305 const uintx token = t->threads_do_token();
1306 assert(token == expected,
1307 "%s " PTR_FORMAT " has incorrect value " UINTX_FORMAT " != "
1308 UINTX_FORMAT, kind, p2i(t), token, expected);
1309 }
1310
1311 void Threads::assert_all_threads_claimed() {
1312 ALL_JAVA_THREADS(p) {
1313 assert_thread_claimed("JavaThread", p, _thread_claim_token);
1314 }
1315
1316 struct NJTClaimedVerifierClosure : public ThreadClosure {
1317 uintx _thread_claim_token;
1318
1319 NJTClaimedVerifierClosure(uintx thread_claim_token) : ThreadClosure(), _thread_claim_token(thread_claim_token) { }
1320
1321 virtual void do_thread(Thread* thread) override {
1322 assert_thread_claimed("Non-JavaThread", VMThread::vm_thread(), _thread_claim_token);
1323 }
1324 } tc(_thread_claim_token);
1325
1326 non_java_threads_do(&tc);
1327 }
1328 #endif // ASSERT
1329
1330 class ParallelOopsDoThreadClosure : public ThreadClosure {
1331 private:
1332 OopClosure* _f;
1333 CodeBlobClosure* _cf;
1334 public:
1335 ParallelOopsDoThreadClosure(OopClosure* f, CodeBlobClosure* cf) : _f(f), _cf(cf) {}
1336 void do_thread(Thread* t) {
1337 t->oops_do(_f, _cf);
1338 }
1339 };
1340
1341 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf) {
1342 ParallelOopsDoThreadClosure tc(f, cf);
1343 possibly_parallel_threads_do(is_par, &tc);
1344 }
1345
1346 void Threads::metadata_do(MetadataClosure* f) {
1347 ALL_JAVA_THREADS(p) {
1348 p->metadata_do(f);
1349 }
1350 }
1351
1352 class ThreadHandlesClosure : public ThreadClosure {
1353 void (*_f)(Metadata*);
1354 public:
1355 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
1356 virtual void do_thread(Thread* thread) {
1357 thread->metadata_handles_do(_f);
1358 }
1359 };
1360
1361 void Threads::metadata_handles_do(void f(Metadata*)) {
1362 // Only walk the Handles in Thread.
1363 ThreadHandlesClosure handles_closure(f);
1364 threads_do(&handles_closure);
1365 }
1366
1367 // Get count Java threads that are waiting to enter the specified monitor.
1368 GrowableArray<JavaThread*>* Threads::get_pending_threads(ThreadsList * t_list,
1369 int count,
1370 address monitor) {
1371 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
1372
1373 int i = 0;
1374 for (JavaThread* p : *t_list) {
1375 if (!p->can_call_java()) continue;
1376
1377 // The first stage of async deflation does not affect any field
1378 // used by this comparison so the ObjectMonitor* is usable here.
1379 address pending = (address)p->current_pending_monitor();
1380 if (pending == monitor) { // found a match
1381 if (i < count) result->append(p); // save the first count matches
1382 i++;
1383 }
1384 }
1385
1386 return result;
1387 }
1388
1389
1390 JavaThread *Threads::owning_thread_from_monitor_owner(ThreadsList * t_list,
1391 address owner) {
1392 assert(!UseFastLocking, "only with stack-locking");
1393 // null owner means not locked so we can skip the search
1394 if (owner == nullptr) return nullptr;
1395
1396 for (JavaThread* p : *t_list) {
1397 // first, see if owner is the address of a Java thread
1398 if (owner == (address)p) return p;
1399 }
1400
1401 // Cannot assert on lack of success here since this function may be
1402 // used by code that is trying to report useful problem information
1403 // like deadlock detection.
1404 if (UseHeavyMonitors) return nullptr;
1405
1406 // If we didn't find a matching Java thread and we didn't force use of
1407 // heavyweight monitors, then the owner is the stack address of the
1408 // Lock Word in the owning Java thread's stack.
1409 //
1410 JavaThread* the_owner = nullptr;
1411 for (JavaThread* q : *t_list) {
1412 if (q->is_lock_owned(owner)) {
1413 the_owner = q;
1414 break;
1415 }
1416 }
1417
1418 // cannot assert on lack of success here; see above comment
1419 return the_owner;
1420 }
1421
1422 JavaThread* Threads::owning_thread_from_object(ThreadsList * t_list, oop obj) {
1423 assert(UseFastLocking, "Only with fast-locking");
1424 for (JavaThread* q : *t_list) {
1425 if (q->lock_stack().contains(obj)) {
1426 return q;
1427 }
1428 }
1429 return nullptr;
1430 }
1431
1432 JavaThread* Threads::owning_thread_from_monitor(ThreadsList* t_list, ObjectMonitor* monitor) {
1433 if (UseFastLocking) {
1434 if (monitor->is_owner_anonymous()) {
1435 return owning_thread_from_object(t_list, monitor->object());
1436 } else {
1437 Thread* owner = reinterpret_cast<Thread*>(monitor->owner());
1438 assert(owner == nullptr || owner->is_Java_thread(), "only JavaThreads own monitors");
1439 return reinterpret_cast<JavaThread*>(owner);
1440 }
1441 } else {
1442 address owner = (address)monitor->owner();
1443 return owning_thread_from_monitor_owner(t_list, owner);
1444 }
1445 }
1446
1447 class PrintOnClosure : public ThreadClosure {
1448 private:
1449 outputStream* _st;
1450
1451 public:
1452 PrintOnClosure(outputStream* st) :
1453 _st(st) {}
1454
1455 virtual void do_thread(Thread* thread) {
1456 if (thread != nullptr) {
1457 thread->print_on(_st);
1458 _st->cr();
1459 }
1460 }
1461 };
1462
1463 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
1464 void Threads::print_on(outputStream* st, bool print_stacks,
1465 bool internal_format, bool print_concurrent_locks,
1466 bool print_extended_info) {
1467 char buf[32];
1468 st->print_raw_cr(os::local_time_string(buf, sizeof(buf)));
1469
1470 st->print_cr("Full thread dump %s (%s %s):",
1471 VM_Version::vm_name(),
1472 VM_Version::vm_release(),
1473 VM_Version::vm_info_string());
1474 st->cr();
1475
1476 #if INCLUDE_SERVICES
1477 // Dump concurrent locks
1478 ConcurrentLocksDump concurrent_locks;
1479 if (print_concurrent_locks) {
1480 concurrent_locks.dump_at_safepoint();
1481 }
1482 #endif // INCLUDE_SERVICES
1483
1484 ThreadsSMRSupport::print_info_on(st);
1485 st->cr();
1486
1487 ALL_JAVA_THREADS(p) {
1488 ResourceMark rm;
1489 p->print_on(st, print_extended_info);
1490 if (print_stacks) {
1491 if (internal_format) {
1492 p->trace_stack();
1493 } else {
1494 p->print_stack_on(st);
1495 }
1496 }
1497 st->cr();
1498 #if INCLUDE_SERVICES
1499 if (print_concurrent_locks) {
1500 concurrent_locks.print_locks_on(p, st);
1501 }
1502 #endif // INCLUDE_SERVICES
1503 }
1504
1505 PrintOnClosure cl(st);
1506 cl.do_thread(VMThread::vm_thread());
1507 Universe::heap()->gc_threads_do(&cl);
1508 if (StringDedup::is_enabled()) {
1509 StringDedup::threads_do(&cl);
1510 }
1511 cl.do_thread(WatcherThread::watcher_thread());
1512 cl.do_thread(AsyncLogWriter::instance());
1513
1514 st->flush();
1515 }
1516
1517 void Threads::print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
1518 int buflen, bool* found_current) {
1519 if (this_thread != nullptr) {
1520 bool is_current = (current == this_thread);
1521 *found_current = *found_current || is_current;
1522 st->print("%s", is_current ? "=>" : " ");
1523
1524 st->print(PTR_FORMAT, p2i(this_thread));
1525 st->print(" ");
1526 this_thread->print_on_error(st, buf, buflen);
1527 st->cr();
1528 }
1529 }
1530
1531 class PrintOnErrorClosure : public ThreadClosure {
1532 outputStream* _st;
1533 Thread* _current;
1534 char* _buf;
1535 int _buflen;
1536 bool* _found_current;
1537 public:
1538 PrintOnErrorClosure(outputStream* st, Thread* current, char* buf,
1539 int buflen, bool* found_current) :
1540 _st(st), _current(current), _buf(buf), _buflen(buflen), _found_current(found_current) {}
1541
1542 virtual void do_thread(Thread* thread) {
1543 Threads::print_on_error(thread, _st, _current, _buf, _buflen, _found_current);
1544 }
1545 };
1546
1547 // Threads::print_on_error() is called by fatal error handler. It's possible
1548 // that VM is not at safepoint and/or current thread is inside signal handler.
1549 // Don't print stack trace, as the stack may not be walkable. Don't allocate
1550 // memory (even in resource area), it might deadlock the error handler.
1551 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
1552 int buflen) {
1553 ThreadsSMRSupport::print_info_on(st);
1554 st->cr();
1555
1556 bool found_current = false;
1557 st->print_cr("Java Threads: ( => current thread )");
1558 ALL_JAVA_THREADS(thread) {
1559 print_on_error(thread, st, current, buf, buflen, &found_current);
1560 }
1561 st->cr();
1562
1563 st->print_cr("Other Threads:");
1564 print_on_error(VMThread::vm_thread(), st, current, buf, buflen, &found_current);
1565 print_on_error(WatcherThread::watcher_thread(), st, current, buf, buflen, &found_current);
1566 print_on_error(AsyncLogWriter::instance(), st, current, buf, buflen, &found_current);
1567
1568 if (Universe::heap() != nullptr) {
1569 PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current);
1570 Universe::heap()->gc_threads_do(&print_closure);
1571 }
1572
1573 if (StringDedup::is_enabled()) {
1574 PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current);
1575 StringDedup::threads_do(&print_closure);
1576 }
1577
1578 if (!found_current) {
1579 st->cr();
1580 st->print("=>" PTR_FORMAT " (exited) ", p2i(current));
1581 current->print_on_error(st, buf, buflen);
1582 st->cr();
1583 }
1584 st->cr();
1585
1586 st->print_cr("Threads with active compile tasks:");
1587 print_threads_compiling(st, buf, buflen);
1588 }
1589
1590 void Threads::print_threads_compiling(outputStream* st, char* buf, int buflen, bool short_form) {
1591 ALL_JAVA_THREADS(thread) {
1592 if (thread->is_Compiler_thread()) {
1593 CompilerThread* ct = (CompilerThread*) thread;
1594
1595 // Keep task in local variable for null check.
1596 // ct->_task might be set to null by concurring compiler thread
1597 // because it completed the compilation. The task is never freed,
1598 // though, just returned to a free list.
1599 CompileTask* task = ct->task();
1600 if (task != nullptr) {
1601 thread->print_name_on_error(st, buf, buflen);
1602 st->print(" ");
1603 task->print(st, nullptr, short_form, true);
1604 }
1605 }
1606 }
1607 }
1608
1609 void Threads::verify() {
1610 ALL_JAVA_THREADS(p) {
1611 p->verify();
1612 }
1613 VMThread* thread = VMThread::vm_thread();
1614 if (thread != nullptr) thread->verify();
1615 }