1 /*
2 * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
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23 */
24
25 #ifndef SHARE_PRIMS_JVMTITHREADSTATE_HPP
26 #define SHARE_PRIMS_JVMTITHREADSTATE_HPP
27
28 #include "jvmtifiles/jvmti.h"
29 #include "memory/allocation.hpp"
30 #include "oops/oopHandle.hpp"
31 #include "prims/jvmtiEventController.hpp"
32 #include "prims/jvmtiExport.hpp"
33 #include "runtime/javaThread.hpp"
34 #include "runtime/mutexLocker.hpp"
35 #include "runtime/threads.hpp"
36 #include "utilities/growableArray.hpp"
37
38 //
39 // Forward Declarations
40 //
41
42 class JvmtiEnvBase;
43 class JvmtiEnvThreadState;
44 class JvmtiDynamicCodeEventCollector;
45
46 class JvmtiDeferredEvent;
47 class JvmtiDeferredEventQueue;
48
49 enum JvmtiClassLoadKind {
50 jvmti_class_load_kind_load = 100,
51 jvmti_class_load_kind_retransform,
52 jvmti_class_load_kind_redefine
53 };
54
55 ///////////////////////////////////////////////////////////////
56 //
57 // class JvmtiEnvThreadStateIterator
58 //
59 // The only safe means of iterating through the JvmtiEnvThreadStates
60 // in a JvmtiThreadState.
61 // Note that this iteratation includes invalid environments pending
62 // deallocation -- in fact, some uses depend on this behavior.
63 //
64 class JvmtiEnvThreadStateIterator : public StackObj {
65 private:
66 JvmtiThreadState* state;
67 public:
68 JvmtiEnvThreadStateIterator(JvmtiThreadState* thread_state);
69 ~JvmtiEnvThreadStateIterator();
70 JvmtiEnvThreadState* first();
71 JvmtiEnvThreadState* next(JvmtiEnvThreadState* ets);
72 };
73
74 ///////////////////////////////////////////////////////////////
75 //
76 // class JvmtiVTMSTransitionDisabler
77 //
78 // Virtual Thread Mount State Transition (VTMS transition) mechanism
79 //
80 class JvmtiVTMSTransitionDisabler : public AnyObj {
81 private:
82 static volatile int _VTMS_transition_disable_for_one_count; // transitions for one virtual thread are disabled while it is positive
83 static volatile int _VTMS_transition_disable_for_all_count; // transitions for all virtual threads are disabled while it is positive
84 static volatile bool _SR_mode; // there is an active suspender or resumer
85 static volatile int _sync_protocol_enabled_count; // current number of JvmtiVTMSTransitionDisablers enabled sync protocol
86 static volatile bool _sync_protocol_enabled_permanently; // seen a suspender: JvmtiVTMSTransitionDisabler protocol is enabled permanently
87
88 bool _is_SR; // is suspender or resumer
89 jthread _thread; // virtual thread to disable transitions for, no-op if it is a platform thread
90
91 DEBUG_ONLY(static void print_info();)
92 void VTMS_transition_disable_for_one();
93 void VTMS_transition_disable_for_all();
94 void VTMS_transition_enable_for_one();
95 void VTMS_transition_enable_for_all();
96
97 public:
98 static bool _VTMS_notify_jvmti_events; // enable notifications from VirtualThread about VTMS events
99 static bool VTMS_notify_jvmti_events() { return _VTMS_notify_jvmti_events; }
100 static void set_VTMS_notify_jvmti_events(bool val) { _VTMS_notify_jvmti_events = val; }
101
102 static void inc_sync_protocol_enabled_count() { Atomic::inc(&_sync_protocol_enabled_count); }
103 static void dec_sync_protocol_enabled_count() { Atomic::dec(&_sync_protocol_enabled_count); }
104 static int sync_protocol_enabled_count() { return Atomic::load(&_sync_protocol_enabled_count); }
105 static bool sync_protocol_enabled_permanently() { return Atomic::load(&_sync_protocol_enabled_permanently); }
106
107 static bool sync_protocol_enabled() { return sync_protocol_enabled_permanently() || sync_protocol_enabled_count() > 0; }
108
109 // parameter is_SR: suspender or resumer
110 JvmtiVTMSTransitionDisabler(bool is_SR = false);
111 JvmtiVTMSTransitionDisabler(jthread thread);
112 ~JvmtiVTMSTransitionDisabler();
113
114 // set VTMS transition bit value in JavaThread and java.lang.VirtualThread object
115 static void set_is_in_VTMS_transition(JavaThread* thread, jobject vthread, bool in_trans);
116
117 static void start_VTMS_transition(jthread vthread, bool is_mount);
118 static void finish_VTMS_transition(jthread vthread, bool is_mount);
119
120 static void VTMS_vthread_start(jobject vthread);
121 static void VTMS_vthread_end(jobject vthread);
122
123 static void VTMS_vthread_mount(jobject vthread, bool hide);
124 static void VTMS_vthread_unmount(jobject vthread, bool hide);
125
126 static void VTMS_mount_begin(jobject vthread);
127 static void VTMS_mount_end(jobject vthread);
128
129 static void VTMS_unmount_begin(jobject vthread, bool last_unmount);
130 static void VTMS_unmount_end(jobject vthread);
131 };
132
133 ///////////////////////////////////////////////////////////////
134 //
135 // class VirtualThreadList
136 //
137 // Used for Virtual Threads Suspend/Resume management.
138 // It's a list of thread IDs.
139 //
140 class VirtualThreadList : public GrowableArrayCHeap<int64_t, mtServiceability> {
141 public:
142 VirtualThreadList() : GrowableArrayCHeap<int64_t, mtServiceability>(0) {}
143 void invalidate() { clear(); }
144 };
145
146 ///////////////////////////////////////////////////////////////
147 //
148 // class JvmtiVTSuspender
149 //
150 // Virtual Threads Suspend/Resume management
151 //
152 class JvmtiVTSuspender : AllStatic {
153 private:
154 // Suspend modes for virtual threads
155 typedef enum SR_Mode {
156 SR_none = 0,
157 SR_ind = 1,
158 SR_all = 2
159 } SR_Mode;
160
161 static SR_Mode _SR_mode;
162 static VirtualThreadList* _suspended_list;
163 static VirtualThreadList* _not_suspended_list;
164
165 public:
166 static void register_all_vthreads_suspend();
167 static void register_all_vthreads_resume();
168 static void register_vthread_suspend(oop vt);
169 static void register_vthread_resume(oop vt);
170 static bool is_vthread_suspended(oop vt);
171 static bool is_vthread_suspended(int64_t thread_id);
172 };
173
174 ///////////////////////////////////////////////////////////////
175 //
176 // class JvmtiThreadState
177 //
178 // The Jvmti state for each thread (across all JvmtiEnv):
179 // 1. Local table of enabled events.
180 class JvmtiThreadState : public CHeapObj<mtInternal> {
181 private:
182 friend class JvmtiEnv;
183 JavaThread *_thread;
184 JavaThread *_thread_saved;
185 OopHandle _thread_oop_h;
186 // Jvmti Events that cannot be posted in their current context.
187 JvmtiDeferredEventQueue* _jvmti_event_queue;
188 bool _is_virtual; // state belongs to a virtual thread
189 bool _hide_single_stepping;
190 bool _pending_interp_only_mode;
191 bool _pending_step_for_popframe;
192 bool _pending_step_for_earlyret;
193 bool _top_frame_is_exiting;
194 int _hide_level;
195
196 public:
197 enum ExceptionState {
198 ES_CLEARED,
199 ES_DETECTED,
200 ES_CAUGHT
201 };
202
203 private:
204 ExceptionState _exception_state;
205
206 // Used to send class being redefined/retransformed and kind of transform
207 // info to the class file load hook event handler.
208 Klass* _class_being_redefined;
209 JvmtiClassLoadKind _class_load_kind;
210 GrowableArray<Klass*>* _classes_being_redefined;
211
212 // This is only valid when is_interp_only_mode() returns true
213 int _cur_stack_depth;
214 int _saved_interp_only_mode;
215
216 JvmtiThreadEventEnable _thread_event_enable;
217
218 // for support of JvmtiEnvThreadState
219 JvmtiEnvThreadState* _head_env_thread_state;
220
221 // doubly-linked linear list of active thread state
222 // needed in order to iterate the list without holding Threads_lock
223 static JvmtiThreadState *_head;
224 JvmtiThreadState *_next;
225 JvmtiThreadState *_prev;
226
227 // holds the current dynamic code event collector, null if no event collector in use
228 JvmtiDynamicCodeEventCollector* _dynamic_code_event_collector;
229 // holds the current vm object alloc event collector, null if no event collector in use
230 JvmtiVMObjectAllocEventCollector* _vm_object_alloc_event_collector;
231 // holds the current sampled object alloc event collector, null if no event collector in use
232 JvmtiSampledObjectAllocEventCollector* _sampled_object_alloc_event_collector;
233
234 // Should only be created by factory methods
235 JvmtiThreadState(JavaThread *thread, oop thread_oop);
236
237 friend class JvmtiEnvThreadStateIterator;
238 inline JvmtiEnvThreadState* head_env_thread_state();
239 inline void set_head_env_thread_state(JvmtiEnvThreadState* ets);
240
241 static bool _seen_interp_only_mode; // interp_only_mode was requested at least once
242
243 public:
244 ~JvmtiThreadState();
245
246 // is event_type enabled and usable for this thread in any environment?
247 bool is_enabled(jvmtiEvent event_type) {
248 return _thread_event_enable.is_enabled(event_type);
249 }
250
251 JvmtiThreadEventEnable *thread_event_enable() {
252 return &_thread_event_enable;
253 }
254
255 // Must only be called in situations where the state is for the current thread and
256 // the environment can not go away. To be safe, the returned JvmtiEnvThreadState
257 // must be used in such a way as there can be no intervening safepoints.
258 inline JvmtiEnvThreadState* env_thread_state(JvmtiEnvBase *env);
259
260 static void periodic_clean_up();
261
262 // Return true if any thread has entered interp_only_mode at any point during the JVMs execution.
263 static bool seen_interp_only_mode() {
264 return _seen_interp_only_mode;
265 }
266
267 void add_env(JvmtiEnvBase *env);
268
269 // The pending_interp_only_mode is set when the interp_only_mode is triggered.
270 // It is cleared by EnterInterpOnlyModeClosure handshake.
271 bool is_pending_interp_only_mode() { return _pending_interp_only_mode; }
272 void set_pending_interp_only_mode(bool val) { _pending_interp_only_mode = val; }
273
274 // Used by the interpreter for fullspeed debugging support
275 bool is_interp_only_mode() {
276 return _thread == nullptr ? _saved_interp_only_mode != 0 : _thread->is_interp_only_mode();
277 }
278 void enter_interp_only_mode();
279 void leave_interp_only_mode();
280
281 static void unbind_from(JvmtiThreadState* state, JavaThread* thread);
282 static void bind_to(JvmtiThreadState* state, JavaThread* thread);
283 static void process_pending_interp_only(JavaThread* current);
284
285 // access to the linked list of all JVMTI thread states
286 static JvmtiThreadState *first() {
287 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check");
288 return _head;
289 }
290
291 JvmtiThreadState *next() {
292 return _next;
293 }
294
295 // Current stack depth is only valid when is_interp_only_mode() returns true.
296 // These functions should only be called at a safepoint - usually called from same thread.
297 // Returns the number of Java activations on the stack.
298 int cur_stack_depth();
299 void invalidate_cur_stack_depth();
300 void incr_cur_stack_depth();
301 void decr_cur_stack_depth();
302
303 int count_frames();
304
305 inline JavaThread *get_thread() { return _thread; }
306 inline JavaThread *get_thread_or_saved(); // return _thread_saved if _thread is null
307
308 // Needed for virtual threads as they can migrate to different JavaThread's.
309 // Also used for carrier threads to clear/restore _thread.
310 void set_thread(JavaThread* thread);
311 oop get_thread_oop();
312
313 inline bool is_virtual() { return _is_virtual; } // the _thread is virtual
314
315 inline bool is_exception_detected() { return _exception_state == ES_DETECTED; }
316 inline bool is_exception_caught() { return _exception_state == ES_CAUGHT; }
317
318 inline void set_exception_detected() { _exception_state = ES_DETECTED; }
319 inline void set_exception_caught() { _exception_state = ES_CAUGHT; }
320
321 inline void clear_exception_state() { _exception_state = ES_CLEARED; }
322
323 // We need to save and restore exception state inside JvmtiEventMark
324 inline ExceptionState get_exception_state() { return _exception_state; }
325 inline void restore_exception_state(ExceptionState state) { _exception_state = state; }
326
327 inline void clear_hide_single_stepping() {
328 if (_hide_level > 0) {
329 _hide_level--;
330 } else {
331 assert(_hide_single_stepping, "hide_single_stepping is out of phase");
332 _hide_single_stepping = false;
333 }
334 }
335 inline bool hide_single_stepping() { return _hide_single_stepping; }
336 inline void set_hide_single_stepping() {
337 if (_hide_single_stepping) {
338 _hide_level++;
339 } else {
340 assert(_hide_level == 0, "hide_level is out of phase");
341 _hide_single_stepping = true;
342 }
343 }
344
345 // Step pending flag is set when PopFrame is called and it is cleared
346 // when step for the Pop Frame is completed.
347 // This logic is used to distinguish b/w step for pop frame and repeat step.
348 void set_pending_step_for_popframe() { _pending_step_for_popframe = true; }
349 void clr_pending_step_for_popframe() { _pending_step_for_popframe = false; }
350 bool is_pending_step_for_popframe() { return _pending_step_for_popframe; }
351 void process_pending_step_for_popframe();
352
353 // Step pending flag is set when ForceEarlyReturn is called and it is cleared
354 // when step for the ForceEarlyReturn is completed.
355 // This logic is used to distinguish b/w step for early return and repeat step.
356 void set_pending_step_for_earlyret() { _pending_step_for_earlyret = true; }
357 void clr_pending_step_for_earlyret() { _pending_step_for_earlyret = false; }
358 bool is_pending_step_for_earlyret() { return _pending_step_for_earlyret; }
359 void process_pending_step_for_earlyret();
360
361 // For synchronization between NotifyFramePop and FramePop posting code.
362 void set_top_frame_is_exiting() { _top_frame_is_exiting = true; }
363 void clr_top_frame_is_exiting() { _top_frame_is_exiting = false; }
364 bool top_frame_is_exiting() { return _top_frame_is_exiting; }
365
366 // Setter and getter method is used to send redefined class info
367 // when class file load hook event is posted.
368 // It is set while loading redefined class and cleared before the
369 // class file load hook event is posted.
370 inline void set_class_being_redefined(Klass* k, JvmtiClassLoadKind kind) {
371 _class_being_redefined = k;
372 _class_load_kind = kind;
373 }
374
375 inline void clear_class_being_redefined() {
376 _class_being_redefined = nullptr;
377 _class_load_kind = jvmti_class_load_kind_load;
378 }
379
380 inline Klass* get_class_being_redefined() {
381 return _class_being_redefined;
382 }
383
384 inline JvmtiClassLoadKind get_class_load_kind() {
385 return _class_load_kind;
386 }
387
388 // Get the classes that are currently being redefined by this thread.
389 inline GrowableArray<Klass*>* get_classes_being_redefined() {
390 return _classes_being_redefined;
391 }
392
393 inline void set_classes_being_redefined(GrowableArray<Klass*>* redef_classes) {
394 _classes_being_redefined = redef_classes;
395 }
396
397 // RedefineClasses support
398 // The bug 6214132 caused the verification to fail.
399 //
400 // What is done at verification:
401 // (This seems to only apply to the old verifier.)
402 // When the verifier makes calls into the VM to ask questions about
403 // the class being verified, it will pass the jclass to JVM_* functions.
404 // The jclass is always pointing to the mirror of _the_class.
405 // ~28 JVM_* functions called by the verifier for the information
406 // about CP entries and klass structure should check the jvmtiThreadState
407 // info about equivalent klass versions and use it to replace a Klass*
408 // of _the_class with a Klass* of _scratch_class. The function
409 // class_to_verify_considering_redefinition() must be called for it.
410 //
411 // Note again, that this redirection happens only for the verifier thread.
412 // Other threads have very small overhead by checking the existence
413 // of the jvmtiThreadSate and the information about klasses equivalence.
414 // No JNI functions need to be changed, they don't reference the klass guts.
415 // The JavaThread pointer is already available in all JVM_* functions
416 // used by the verifier, so there is no extra performance issue with it.
417
418 private:
419 Klass* _the_class_for_redefinition_verification;
420 Klass* _scratch_class_for_redefinition_verification;
421
422 public:
423 inline void set_class_versions_map(Klass* the_class,
424 Klass* scratch_class) {
425 _the_class_for_redefinition_verification = the_class;
426 _scratch_class_for_redefinition_verification = scratch_class;
427 }
428
429 inline void clear_class_versions_map() { set_class_versions_map(nullptr, nullptr); }
430
431 static inline
432 Klass* class_to_verify_considering_redefinition(Klass* klass,
433 JavaThread *thread) {
434 JvmtiThreadState *state = thread->jvmti_thread_state();
435 if (state != nullptr && state->_the_class_for_redefinition_verification != nullptr) {
436 if (state->_the_class_for_redefinition_verification == klass) {
437 klass = state->_scratch_class_for_redefinition_verification;
438 }
439 }
440 return klass;
441 }
442
443 // Todo: get rid of this!
444 private:
445 bool _debuggable;
446 public:
447 // Should the thread be enumerated by jvmtiInternal::GetAllThreads?
448 bool is_debuggable() { return _debuggable; }
449 // If a thread cannot be suspended (has no valid last_java_frame) then it gets marked !debuggable
450 void set_debuggable(bool debuggable) { _debuggable = debuggable; }
451
452 public:
453
454 // Thread local event collector setter and getter methods.
455 JvmtiDynamicCodeEventCollector* get_dynamic_code_event_collector() {
456 return _dynamic_code_event_collector;
457 }
458 JvmtiVMObjectAllocEventCollector* get_vm_object_alloc_event_collector() {
459 return _vm_object_alloc_event_collector;
460 }
461 JvmtiSampledObjectAllocEventCollector* get_sampled_object_alloc_event_collector() {
462 return _sampled_object_alloc_event_collector;
463 }
464 void set_dynamic_code_event_collector(JvmtiDynamicCodeEventCollector* collector) {
465 _dynamic_code_event_collector = collector;
466 }
467 void set_vm_object_alloc_event_collector(JvmtiVMObjectAllocEventCollector* collector) {
468 _vm_object_alloc_event_collector = collector;
469 }
470 void set_sampled_object_alloc_event_collector(JvmtiSampledObjectAllocEventCollector* collector) {
471 _sampled_object_alloc_event_collector = collector;
472 }
473
474
475 //
476 // Frame routines
477 //
478
479 public:
480
481 // true when the thread was suspended with a pointer to the last Java frame.
482 bool has_last_frame() { return _thread->has_last_Java_frame(); }
483
484 void update_for_pop_top_frame();
485
486 // already holding JvmtiThreadState_lock - retrieve or create JvmtiThreadState
487 // Can return null if JavaThread is exiting.
488 // Callers are responsible to call recompute_thread_filtered() to update event bits
489 // if thread-filtered events are enabled globally.
490 static JvmtiThreadState *state_for_while_locked(JavaThread *thread, oop thread_oop = nullptr);
491 // retrieve or create JvmtiThreadState
492 // Can return null if JavaThread is exiting.
493 // Calls recompute_thread_filtered() to update event bits if thread-filtered events are enabled globally.
494 static JvmtiThreadState *state_for(JavaThread *thread, Handle thread_handle = Handle());
495
496 // JVMTI ForceEarlyReturn support
497
498 // This is set to earlyret_pending to signal that top Java frame
499 // should be returned immediately
500 public:
501 int _earlyret_state;
502 TosState _earlyret_tos;
503 jvalue _earlyret_value;
504 oop _earlyret_oop; // Used to return an oop result into Java code from
505 // ForceEarlyReturnObject, GC-preserved
506
507 // Setting and clearing earlyret_state
508 // earlyret_pending indicates that a ForceEarlyReturn() has been
509 // requested and not yet been completed.
510 public:
511 enum EarlyretState {
512 earlyret_inactive = 0,
513 earlyret_pending = 1
514 };
515
516 void set_earlyret_pending(void) { _earlyret_state = earlyret_pending; }
517 void clr_earlyret_pending(void) { _earlyret_state = earlyret_inactive; }
518 bool is_earlyret_pending(void) { return (_earlyret_state == earlyret_pending); }
519
520 TosState earlyret_tos() { return _earlyret_tos; }
521 oop earlyret_oop() const { return _earlyret_oop; }
522 void set_earlyret_oop (oop x) { _earlyret_oop = x; }
523 jvalue earlyret_value() { return _earlyret_value; }
524 void set_earlyret_value(jvalue val, TosState tos) { _earlyret_tos = tos; _earlyret_value = val; }
525 void clr_earlyret_value() { _earlyret_tos = ilgl; _earlyret_value.j = 0L; }
526
527 static ByteSize earlyret_state_offset() { return byte_offset_of(JvmtiThreadState, _earlyret_state); }
528 static ByteSize earlyret_tos_offset() { return byte_offset_of(JvmtiThreadState, _earlyret_tos); }
529 static ByteSize earlyret_oop_offset() { return byte_offset_of(JvmtiThreadState, _earlyret_oop); }
530 static ByteSize earlyret_value_offset() { return byte_offset_of(JvmtiThreadState, _earlyret_value); }
531
532 void oops_do(OopClosure* f, NMethodClosure* cf) NOT_JVMTI_RETURN; // GC support
533 void nmethods_do(NMethodClosure* cf) NOT_JVMTI_RETURN;
534
535 public:
536 void set_should_post_on_exceptions(bool val);
537
538 // Thread local event queue, which doesn't require taking the Service_lock.
539 void enqueue_event(JvmtiDeferredEvent* event) NOT_JVMTI_RETURN;
540 void post_events(JvmtiEnv* env);
541 void run_nmethod_entry_barriers();
542 };
543
544 #endif // SHARE_PRIMS_JVMTITHREADSTATE_HPP