1 /*
2 * Copyright (c) 1997, 2019, 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.
22 *
23 */
24
25 #ifndef SHARE_RUNTIME_INTERFACESUPPORT_INLINE_HPP
26 #define SHARE_RUNTIME_INTERFACESUPPORT_INLINE_HPP
27
28 #include "runtime/handles.inline.hpp"
29 #include "runtime/mutexLocker.hpp"
30 #include "runtime/orderAccess.hpp"
31 #include "runtime/os.hpp"
32 #include "runtime/safepointMechanism.inline.hpp"
33 #include "runtime/safepointVerifiers.hpp"
34 #include "runtime/thread.hpp"
35 #include "runtime/vmOperations.hpp"
36 #include "utilities/globalDefinitions.hpp"
37 #include "utilities/histogram.hpp"
38 #include "utilities/macros.hpp"
39 #include "utilities/preserveException.hpp"
40
41 // Wrapper for all entry points to the virtual machine.
42
43 // InterfaceSupport provides functionality used by the VM_LEAF_BASE and
44 // VM_ENTRY_BASE macros. These macros are used to guard entry points into
45 // the VM and perform checks upon leave of the VM.
46
47
48 class InterfaceSupport: AllStatic {
49 # ifdef ASSERT
50 public:
51 static long _scavenge_alot_counter;
52 static long _fullgc_alot_counter;
53 static long _number_of_calls;
54 static long _fullgc_alot_invocation;
55
56 // Helper methods used to implement +ScavengeALot and +FullGCALot
57 static void check_gc_alot() { if (ScavengeALot || FullGCALot) gc_alot(); }
58 static void gc_alot();
59
60 static void walk_stack_from(vframe* start_vf);
61 static void walk_stack();
62
63 static void zombieAll();
64 static void deoptimizeAll();
65 static void deoptimizeAllObjects();
66 static void stress_derived_pointers();
67 static void verify_stack();
68 static void verify_last_frame();
69 # endif
70 };
71
72
73 // Basic class for all thread transition classes.
74
75 class ThreadStateTransition : public StackObj {
76 protected:
77 JavaThread* _thread;
78 public:
79 ThreadStateTransition(JavaThread *thread) {
80 _thread = thread;
81 assert(thread != NULL && thread->is_Java_thread(), "must be Java thread");
82 }
83
84 // Change threadstate in a manner, so safepoint can detect changes.
85 // Time-critical: called on exit from every runtime routine
86 static inline void transition(JavaThread *thread, JavaThreadState from, JavaThreadState to) {
87 assert(from != _thread_in_Java, "use transition_from_java");
88 assert(from != _thread_in_native, "use transition_from_native");
89 assert((from & 1) == 0 && (to & 1) == 0, "odd numbers are transitions states");
90 assert(thread->thread_state() == from, "coming from wrong thread state");
91
92 // Check NoSafepointVerifier
93 // This also clears unhandled oops if CheckUnhandledOops is used.
94 thread->check_possible_safepoint();
95
96 // Change to transition state and ensure it is seen by the VM thread.
97 thread->set_thread_state_fence((JavaThreadState)(from + 1));
98
99 SafepointMechanism::block_if_requested(thread);
100 thread->set_thread_state(to);
101 }
102
103 // Same as above, but assumes from = _thread_in_Java. This is simpler, since we
104 // never block on entry to the VM. This will break the code, since e.g. preserve arguments
105 // have not been setup.
106 static inline void transition_from_java(JavaThread *thread, JavaThreadState to) {
107 assert(thread->thread_state() == _thread_in_Java, "coming from wrong thread state");
108 thread->set_thread_state(to);
109 }
110
111 static inline void transition_from_native(JavaThread *thread, JavaThreadState to) {
112 assert((to & 1) == 0, "odd numbers are transitions states");
113 assert(thread->thread_state() == _thread_in_native, "coming from wrong thread state");
114 // Change to transition state and ensure it is seen by the VM thread.
115 thread->set_thread_state_fence(_thread_in_native_trans);
116
117 // We never install asynchronous exceptions when coming (back) in
118 // to the runtime from native code because the runtime is not set
119 // up to handle exceptions floating around at arbitrary points.
120 if (SafepointMechanism::should_block(thread) || thread->is_suspend_after_native()) {
121 JavaThread::check_safepoint_and_suspend_for_native_trans(thread);
122 }
123
124 thread->set_thread_state(to);
125 }
126 protected:
127 void trans(JavaThreadState from, JavaThreadState to) { transition(_thread, from, to); }
128 void trans_from_java(JavaThreadState to) { transition_from_java(_thread, to); }
129 void trans_from_native(JavaThreadState to) { transition_from_native(_thread, to); }
130 };
131
132 class ThreadInVMForHandshake : public ThreadStateTransition {
133 const JavaThreadState _original_state;
134
135 void transition_back() {
136 // This can be invoked from transition states and must return to the original state properly
137 assert(_thread->thread_state() == _thread_in_vm, "should only call when leaving VM after handshake");
138 // Change to transition state and ensure it is seen by the VM thread.
139 _thread->set_thread_state_fence(_thread_in_vm_trans);
140
141 SafepointMechanism::block_if_requested(_thread);
142
143 _thread->set_thread_state(_original_state);
144
145 if (_original_state != _thread_blocked_trans && _original_state != _thread_in_vm_trans &&
146 _thread->has_special_runtime_exit_condition()) {
147 _thread->handle_special_runtime_exit_condition(
148 !_thread->is_at_poll_safepoint() && (_original_state != _thread_in_native_trans));
149 }
150 }
151
152 public:
153
154 ThreadInVMForHandshake(JavaThread* thread) : ThreadStateTransition(thread),
155 _original_state(thread->thread_state()) {
156
157 if (thread->has_last_Java_frame()) {
158 thread->frame_anchor()->make_walkable(thread);
159 }
160
161 thread->set_thread_state(_thread_in_vm);
162 }
163
164 ~ThreadInVMForHandshake() {
165 transition_back();
166 }
167
168 };
169
170 class ThreadInVMfromJava : public ThreadStateTransition {
171 public:
172 ThreadInVMfromJava(JavaThread* thread) : ThreadStateTransition(thread) {
173 trans_from_java(_thread_in_vm);
174 }
175 ~ThreadInVMfromJava() {
176 if (_thread->stack_yellow_reserved_zone_disabled()) {
177 _thread->enable_stack_yellow_reserved_zone();
178 }
179 trans(_thread_in_vm, _thread_in_Java);
180 // Check for pending. async. exceptions or suspends.
181 if (_thread->has_special_runtime_exit_condition()) _thread->handle_special_runtime_exit_condition();
182 }
183 };
184
185
186 class ThreadInVMfromUnknown {
187 JavaThread* _thread;
188 public:
189 ThreadInVMfromUnknown() : _thread(NULL) {
190 Thread* t = Thread::current();
191 if (t->is_Java_thread()) {
192 JavaThread* t2 = (JavaThread*) t;
193 if (t2->thread_state() == _thread_in_native) {
194 _thread = t2;
195 ThreadStateTransition::transition_from_native(t2, _thread_in_vm);
196 // Used to have a HandleMarkCleaner but that is dangerous as
197 // it could free a handle in our (indirect, nested) caller.
198 // We expect any handles will be short lived and figure we
199 // don't need an actual HandleMark.
200 }
201 }
202 }
203 ~ThreadInVMfromUnknown() {
204 if (_thread) {
205 ThreadStateTransition::transition(_thread, _thread_in_vm, _thread_in_native);
206 }
207 }
208 };
209
210
211 class ThreadInVMfromNative : public ThreadStateTransition {
212 public:
213 ThreadInVMfromNative(JavaThread* thread) : ThreadStateTransition(thread) {
214 trans_from_native(_thread_in_vm);
215 }
216 ~ThreadInVMfromNative() {
217 trans(_thread_in_vm, _thread_in_native);
218 }
219 };
220
221
222 class ThreadToNativeFromVM : public ThreadStateTransition {
223 public:
224 ThreadToNativeFromVM(JavaThread *thread) : ThreadStateTransition(thread) {
225 // We are leaving the VM at this point and going directly to native code.
226 // Block, if we are in the middle of a safepoint synchronization.
227 assert(!thread->owns_locks(), "must release all locks when leaving VM");
228 thread->frame_anchor()->make_walkable(thread);
229 trans(_thread_in_vm, _thread_in_native);
230 // Check for pending. async. exceptions or suspends.
231 if (_thread->has_special_runtime_exit_condition()) _thread->handle_special_runtime_exit_condition(false);
232 }
233
234 ~ThreadToNativeFromVM() {
235 trans_from_native(_thread_in_vm);
236 assert(!_thread->is_pending_jni_exception_check(), "Pending JNI Exception Check");
237 // We don't need to clear_walkable because it will happen automagically when we return to java
238 }
239 };
240
241
242 class ThreadBlockInVM : public ThreadStateTransition {
243 public:
244 ThreadBlockInVM(JavaThread *thread)
245 : ThreadStateTransition(thread) {
246 // Once we are blocked vm expects stack to be walkable
247 thread->frame_anchor()->make_walkable(thread);
248 trans(_thread_in_vm, _thread_blocked);
249 }
250 ~ThreadBlockInVM() {
251 trans(_thread_blocked, _thread_in_vm);
252 OrderAccess::cross_modify_fence();
253 // We don't need to clear_walkable because it will happen automagically when we return to java
254 }
255 };
256
257 // Unlike ThreadBlockInVM, this class is designed to avoid certain deadlock scenarios while making
258 // transitions inside class Mutex in cases where we need to block for a safepoint or handshake. It
259 // receives an extra argument compared to ThreadBlockInVM, the address of a pointer to the mutex we
260 // are trying to acquire. This will be used to access and release the mutex if needed to avoid
261 // said deadlocks.
262 // It works like ThreadBlockInVM but differs from it in two ways:
263 // - When transitioning in (constructor), it checks for safepoints without blocking, i.e., calls
264 // back if needed to allow a pending safepoint to continue but does not block in it.
265 // - When transitioning back (destructor), if there is a pending safepoint or handshake it releases
266 // the mutex that is only partially acquired.
267 class ThreadBlockInVMWithDeadlockCheck : public ThreadStateTransition {
268 private:
269 Mutex** _in_flight_mutex_addr;
270
271 void release_mutex() {
272 assert(_in_flight_mutex_addr != NULL, "_in_flight_mutex_addr should have been set on constructor");
273 Mutex* in_flight_mutex = *_in_flight_mutex_addr;
274 if (in_flight_mutex != NULL) {
275 in_flight_mutex->release_for_safepoint();
276 *_in_flight_mutex_addr = NULL;
277 }
278 }
279 public:
280 ThreadBlockInVMWithDeadlockCheck(JavaThread* thread, Mutex** in_flight_mutex_addr)
281 : ThreadStateTransition(thread), _in_flight_mutex_addr(in_flight_mutex_addr) {
282 // Once we are blocked vm expects stack to be walkable
283 thread->frame_anchor()->make_walkable(thread);
284
285 // All unsafe states are treated the same by the VMThread
286 // so we can skip the _thread_in_vm_trans state here. Since
287 // we don't read poll, it's enough to order the stores.
288 OrderAccess::storestore();
289
290 thread->set_thread_state(_thread_blocked);
291 }
292 ~ThreadBlockInVMWithDeadlockCheck() {
293 // Change to transition state and ensure it is seen by the VM thread.
294 _thread->set_thread_state_fence((JavaThreadState)(_thread_blocked_trans));
295
296 if (SafepointMechanism::should_block(_thread)) {
297 release_mutex();
298 SafepointMechanism::block_if_requested(_thread);
299 }
300
301 _thread->set_thread_state(_thread_in_vm);
302 OrderAccess::cross_modify_fence();
303 }
304 };
305
306
307 // This special transition class is only used to prevent asynchronous exceptions
308 // from being installed on vm exit in situations where we can't tolerate them.
309 // See bugs: 4324348, 4854693, 4998314, 5040492, 5050705.
310 class ThreadInVMfromJavaNoAsyncException : public ThreadStateTransition {
311 public:
312 ThreadInVMfromJavaNoAsyncException(JavaThread* thread) : ThreadStateTransition(thread) {
313 trans_from_java(_thread_in_vm);
314 }
315 ~ThreadInVMfromJavaNoAsyncException() {
316 if (_thread->stack_yellow_reserved_zone_disabled()) {
317 _thread->enable_stack_yellow_reserved_zone();
318 }
319 trans(_thread_in_vm, _thread_in_Java);
320 // NOTE: We do not check for pending. async. exceptions.
321 // If we did and moved the pending async exception over into the
322 // pending exception field, we would need to deopt (currently C2
323 // only). However, to do so would require that we transition back
324 // to the _thread_in_vm state. Instead we postpone the handling of
325 // the async exception.
326
327
328 // Check for pending. suspends only.
329 if (_thread->has_special_runtime_exit_condition())
330 _thread->handle_special_runtime_exit_condition(false);
331 }
332 };
333
334 // Debug class instantiated in JRT_ENTRY macro.
335 // Can be used to verify properties on enter/exit of the VM.
336
337 #ifdef ASSERT
338 class VMEntryWrapper {
339 public:
340 VMEntryWrapper();
341 ~VMEntryWrapper();
342 };
343
344
345 class VMNativeEntryWrapper {
346 public:
347 VMNativeEntryWrapper();
348 ~VMNativeEntryWrapper();
349 };
350
351 class RuntimeHistogramElement : public HistogramElement {
352 public:
353 RuntimeHistogramElement(const char* name);
354 };
355 #endif // ASSERT
356
357 #ifdef ASSERT
358 #define TRACE_CALL(result_type, header) \
359 InterfaceSupport::_number_of_calls++; \
360 if (CountRuntimeCalls) { \
361 static RuntimeHistogramElement* e = new RuntimeHistogramElement(#header); \
362 if (e != NULL) e->increment_count(); \
363 }
364 #else
365 #define TRACE_CALL(result_type, header) \
366 /* do nothing */
367 #endif // ASSERT
368
369
370 // LEAF routines do not lock, GC or throw exceptions
371
372 #define VM_LEAF_BASE(result_type, header) \
373 TRACE_CALL(result_type, header) \
374 debug_only(NoHandleMark __hm;) \
375 os::verify_stack_alignment(); \
376 /* begin of body */
377
378 #define VM_ENTRY_BASE_FROM_LEAF(result_type, header, thread) \
379 TRACE_CALL(result_type, header) \
380 debug_only(ResetNoHandleMark __rnhm;) \
381 HandleMarkCleaner __hm(thread); \
382 Thread* THREAD = thread; \
383 os::verify_stack_alignment(); \
384 /* begin of body */
385
386
387 // ENTRY routines may lock, GC and throw exceptions
388
389 #define VM_ENTRY_BASE(result_type, header, thread) \
390 TRACE_CALL(result_type, header) \
391 HandleMarkCleaner __hm(thread); \
392 Thread* THREAD = thread; \
393 os::verify_stack_alignment(); \
394 /* begin of body */
395
396
397 // QUICK_ENTRY routines behave like ENTRY but without a handle mark
398
399 #define VM_QUICK_ENTRY_BASE(result_type, header, thread) \
400 TRACE_CALL(result_type, header) \
401 debug_only(NoHandleMark __hm;) \
402 Thread* THREAD = thread; \
403 os::verify_stack_alignment(); \
404 /* begin of body */
405
406
407 #define JRT_ENTRY(result_type, header) \
408 result_type header { \
409 ThreadInVMfromJava __tiv(thread); \
410 VM_ENTRY_BASE(result_type, header, thread) \
411 debug_only(VMEntryWrapper __vew;)
412
413 // JRT_LEAF currently can be called from either _thread_in_Java or
414 // _thread_in_native mode.
415 //
416 // JRT_LEAF rules:
417 // A JRT_LEAF method may not interfere with safepointing by
418 // 1) acquiring or blocking on a Mutex or JavaLock - checked
419 // 2) allocating heap memory - checked
420 // 3) executing a VM operation - checked
421 // 4) executing a system call (including malloc) that could block or grab a lock
422 // 5) invoking GC
423 // 6) reaching a safepoint
424 // 7) running too long
425 // Nor may any method it calls.
426
427 #define JRT_LEAF(result_type, header) \
428 result_type header { \
429 VM_LEAF_BASE(result_type, header) \
430 debug_only(NoSafepointVerifier __nsv;)
431
432
433 #define JRT_ENTRY_NO_ASYNC(result_type, header) \
434 result_type header { \
435 ThreadInVMfromJavaNoAsyncException __tiv(thread); \
436 VM_ENTRY_BASE(result_type, header, thread) \
437 debug_only(VMEntryWrapper __vew;)
438
439 // Same as JRT Entry but allows for return value after the safepoint
440 // to get back into Java from the VM
441 #define JRT_BLOCK_ENTRY(result_type, header) \
442 result_type header { \
443 TRACE_CALL(result_type, header) \
444 HandleMarkCleaner __hm(thread);
445
446 #define JRT_BLOCK \
447 { \
448 ThreadInVMfromJava __tiv(thread); \
449 Thread* THREAD = thread; \
450 debug_only(VMEntryWrapper __vew;)
451
452 #define JRT_BLOCK_NO_ASYNC \
453 { \
454 ThreadInVMfromJavaNoAsyncException __tiv(thread); \
455 Thread* THREAD = thread; \
456 debug_only(VMEntryWrapper __vew;)
457
458 #define JRT_BLOCK_END }
459
460 #define JRT_END }
461
462 // Definitions for JNI
463
464 #define JNI_ENTRY(result_type, header) \
465 JNI_ENTRY_NO_PRESERVE(result_type, header) \
466 WeakPreserveExceptionMark __wem(thread);
467
468 #define JNI_ENTRY_NO_PRESERVE(result_type, header) \
469 extern "C" { \
470 result_type JNICALL header { \
471 JavaThread* thread=JavaThread::thread_from_jni_environment(env); \
472 assert( !VerifyJNIEnvThread || (thread == Thread::current()), "JNIEnv is only valid in same thread"); \
473 ThreadInVMfromNative __tiv(thread); \
474 debug_only(VMNativeEntryWrapper __vew;) \
475 VM_ENTRY_BASE(result_type, header, thread)
476
477
478 // Ensure that the VMNativeEntryWrapper constructor, which can cause
479 // a GC, is called outside the NoHandleMark (set via VM_QUICK_ENTRY_BASE).
480 #define JNI_QUICK_ENTRY(result_type, header) \
481 extern "C" { \
482 result_type JNICALL header { \
483 JavaThread* thread=JavaThread::thread_from_jni_environment(env); \
484 assert( !VerifyJNIEnvThread || (thread == Thread::current()), "JNIEnv is only valid in same thread"); \
485 ThreadInVMfromNative __tiv(thread); \
486 debug_only(VMNativeEntryWrapper __vew;) \
487 VM_QUICK_ENTRY_BASE(result_type, header, thread)
488
489
490 #define JNI_LEAF(result_type, header) \
491 extern "C" { \
492 result_type JNICALL header { \
493 JavaThread* thread=JavaThread::thread_from_jni_environment(env); \
494 assert( !VerifyJNIEnvThread || (thread == Thread::current()), "JNIEnv is only valid in same thread"); \
495 VM_LEAF_BASE(result_type, header)
496
497
498 // Close the routine and the extern "C"
499 #define JNI_END } }
500
501
502
503 // Definitions for JVM
504
505 #define JVM_ENTRY(result_type, header) \
506 extern "C" { \
507 result_type JNICALL header { \
508 JavaThread* thread=JavaThread::thread_from_jni_environment(env); \
509 ThreadInVMfromNative __tiv(thread); \
510 debug_only(VMNativeEntryWrapper __vew;) \
511 VM_ENTRY_BASE(result_type, header, thread)
512
513
514 #define JVM_ENTRY_NO_ENV(result_type, header) \
515 extern "C" { \
516 result_type JNICALL header { \
517 JavaThread* thread = JavaThread::current(); \
518 ThreadInVMfromNative __tiv(thread); \
519 debug_only(VMNativeEntryWrapper __vew;) \
520 VM_ENTRY_BASE(result_type, header, thread)
521
522
523 #define JVM_QUICK_ENTRY(result_type, header) \
524 extern "C" { \
525 result_type JNICALL header { \
526 JavaThread* thread=JavaThread::thread_from_jni_environment(env); \
527 ThreadInVMfromNative __tiv(thread); \
528 debug_only(VMNativeEntryWrapper __vew;) \
529 VM_QUICK_ENTRY_BASE(result_type, header, thread)
530
531
532 #define JVM_LEAF(result_type, header) \
533 extern "C" { \
534 result_type JNICALL header { \
535 VM_Exit::block_if_vm_exited(); \
536 VM_LEAF_BASE(result_type, header)
537
538
539 #define JVM_ENTRY_FROM_LEAF(env, result_type, header) \
540 { { \
541 JavaThread* thread=JavaThread::thread_from_jni_environment(env); \
542 ThreadInVMfromNative __tiv(thread); \
543 debug_only(VMNativeEntryWrapper __vew;) \
544 VM_ENTRY_BASE_FROM_LEAF(result_type, header, thread)
545
546
547 #define JVM_END } }
548
549 #endif // SHARE_RUNTIME_INTERFACESUPPORT_INLINE_HPP