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