1 /*
2 * Copyright (c) 1997, 2007, 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 // Wrapper for all entry points to the virtual machine.
26 // The HandleMarkCleaner is a faster version of HandleMark.
27 // It relies on the fact that there is a HandleMark further
28 // down the stack (in JavaCalls::call_helper), and just resets
29 // to the saved values in that HandleMark.
30
31 class HandleMarkCleaner: public StackObj {
32 private:
33 Thread* _thread;
34 public:
35 HandleMarkCleaner(Thread* thread) {
36 _thread = thread;
37 _thread->last_handle_mark()->push();
38 }
39 ~HandleMarkCleaner() {
40 _thread->last_handle_mark()->pop_and_restore();
41 }
42
43 private:
44 inline void* operator new(size_t size, void* ptr) {
45 return ptr;
46 }
47 };
48
49 // InterfaceSupport provides functionality used by the __LEAF and __ENTRY
50 // macros. These macros are used to guard entry points into the VM and
51 // perform checks upon leave of the VM.
52
53
54 class InterfaceSupport: AllStatic {
55 # ifdef ASSERT
56 public:
57 static long _scavenge_alot_counter;
58 static long _fullgc_alot_counter;
59 static long _number_of_calls;
60 static long _fullgc_alot_invocation;
61
62 // tracing
63 static void trace(const char* result_type, const char* header);
64
65 // Helper methods used to implement +ScavengeALot and +FullGCALot
66 static void check_gc_alot() { if (ScavengeALot || FullGCALot) gc_alot(); }
67 static void gc_alot();
68
69 static void walk_stack_from(vframe* start_vf);
70 static void walk_stack();
71
72 # ifdef ENABLE_ZAP_DEAD_LOCALS
73 static void zap_dead_locals_old();
74 # endif
75
76 static void zombieAll();
77 static void deoptimizeAll();
78 static void stress_derived_pointers();
79 static void verify_stack();
80 static void verify_last_frame();
81 # endif
82
83 public:
84 // OS dependent stuff
85 #include "incls/_interfaceSupport_pd.hpp.incl"
86 };
87
88
89 // Basic class for all thread transition classes.
90
91 class ThreadStateTransition : public StackObj {
92 protected:
93 JavaThread* _thread;
94 public:
95 ThreadStateTransition(JavaThread *thread) {
96 _thread = thread;
97 assert(thread != NULL && thread->is_Java_thread(), "must be Java thread");
98 }
99
100 // Change threadstate in a manner, so safepoint can detect changes.
101 // Time-critical: called on exit from every runtime routine
102 static inline void transition(JavaThread *thread, JavaThreadState from, JavaThreadState to) {
103 assert(from != _thread_in_Java, "use transition_from_java");
104 assert(from != _thread_in_native, "use transition_from_native");
105 assert((from & 1) == 0 && (to & 1) == 0, "odd numbers are transitions states");
106 assert(thread->thread_state() == from, "coming from wrong thread state");
107 // Change to transition state (assumes total store ordering! -Urs)
108 thread->set_thread_state((JavaThreadState)(from + 1));
109
110 // Make sure new state is seen by VM thread
111 if (os::is_MP()) {
112 if (UseMembar) {
113 // Force a fence between the write above and read below
114 OrderAccess::fence();
115 } else {
116 // store to serialize page so VM thread can do pseudo remote membar
117 os::write_memory_serialize_page(thread);
118 }
119 }
120
121 if (SafepointSynchronize::do_call_back()) {
122 SafepointSynchronize::block(thread);
123 }
124 thread->set_thread_state(to);
125
126 CHECK_UNHANDLED_OOPS_ONLY(thread->clear_unhandled_oops();)
127 }
128
129 // transition_and_fence must be used on any thread state transition
130 // where there might not be a Java call stub on the stack, in
131 // particular on Windows where the Structured Exception Handler is
132 // set up in the call stub. os::write_memory_serialize_page() can
133 // fault and we can't recover from it on Windows without a SEH in
134 // place.
135 static inline void transition_and_fence(JavaThread *thread, JavaThreadState from, JavaThreadState to) {
136 assert(thread->thread_state() == from, "coming from wrong thread state");
137 assert((from & 1) == 0 && (to & 1) == 0, "odd numbers are transitions states");
138 // Change to transition state (assumes total store ordering! -Urs)
139 thread->set_thread_state((JavaThreadState)(from + 1));
140
141 // Make sure new state is seen by VM thread
142 if (os::is_MP()) {
143 if (UseMembar) {
144 // Force a fence between the write above and read below
145 OrderAccess::fence();
146 } else {
147 // Must use this rather than serialization page in particular on Windows
148 InterfaceSupport::serialize_memory(thread);
149 }
150 }
151
152 if (SafepointSynchronize::do_call_back()) {
153 SafepointSynchronize::block(thread);
154 }
155 thread->set_thread_state(to);
156
157 CHECK_UNHANDLED_OOPS_ONLY(thread->clear_unhandled_oops();)
158 }
159
160 // Same as above, but assumes from = _thread_in_Java. This is simpler, since we
161 // never block on entry to the VM. This will break the code, since e.g. preserve arguments
162 // have not been setup.
163 static inline void transition_from_java(JavaThread *thread, JavaThreadState to) {
164 assert(thread->thread_state() == _thread_in_Java, "coming from wrong thread state");
165 thread->set_thread_state(to);
166 }
167
168 static inline void transition_from_native(JavaThread *thread, JavaThreadState to) {
169 assert((to & 1) == 0, "odd numbers are transitions states");
170 assert(thread->thread_state() == _thread_in_native, "coming from wrong thread state");
171 // Change to transition state (assumes total store ordering! -Urs)
172 thread->set_thread_state(_thread_in_native_trans);
173
174 // Make sure new state is seen by GC thread
175 if (os::is_MP()) {
176 if (UseMembar) {
177 // Force a fence between the write above and read below
178 OrderAccess::fence();
179 } else {
180 // Must use this rather than serialization page in particular on Windows
181 InterfaceSupport::serialize_memory(thread);
182 }
183 }
184
185 // We never install asynchronous exceptions when coming (back) in
186 // to the runtime from native code because the runtime is not set
187 // up to handle exceptions floating around at arbitrary points.
188 if (SafepointSynchronize::do_call_back() || thread->is_suspend_after_native()) {
189 JavaThread::check_safepoint_and_suspend_for_native_trans(thread);
190
191 // Clear unhandled oops anywhere where we could block, even if we don't.
192 CHECK_UNHANDLED_OOPS_ONLY(thread->clear_unhandled_oops();)
193 }
194
195 thread->set_thread_state(to);
196 }
197 protected:
198 void trans(JavaThreadState from, JavaThreadState to) { transition(_thread, from, to); }
199 void trans_from_java(JavaThreadState to) { transition_from_java(_thread, to); }
200 void trans_from_native(JavaThreadState to) { transition_from_native(_thread, to); }
201 void trans_and_fence(JavaThreadState from, JavaThreadState to) { transition_and_fence(_thread, from, to); }
202 };
203
204
205 class ThreadInVMfromJava : public ThreadStateTransition {
206 public:
207 ThreadInVMfromJava(JavaThread* thread) : ThreadStateTransition(thread) {
208 trans_from_java(_thread_in_vm);
209 }
210 ~ThreadInVMfromJava() {
211 trans(_thread_in_vm, _thread_in_Java);
212 // Check for pending. async. exceptions or suspends.
213 if (_thread->has_special_runtime_exit_condition()) _thread->handle_special_runtime_exit_condition();
214 }
215 };
216
217
218 class ThreadInVMfromUnknown {
219 private:
220 JavaThread* _thread;
221 public:
222 ThreadInVMfromUnknown() : _thread(NULL) {
223 Thread* t = Thread::current();
224 if (t->is_Java_thread()) {
225 JavaThread* t2 = (JavaThread*) t;
226 if (t2->thread_state() == _thread_in_native) {
227 _thread = t2;
228 ThreadStateTransition::transition_from_native(t2, _thread_in_vm);
229 // Used to have a HandleMarkCleaner but that is dangerous as
230 // it could free a handle in our (indirect, nested) caller.
231 // We expect any handles will be short lived and figure we
232 // don't need an actual HandleMark.
233 }
234 }
235 }
236 ~ThreadInVMfromUnknown() {
237 if (_thread) {
238 ThreadStateTransition::transition_and_fence(_thread, _thread_in_vm, _thread_in_native);
239 }
240 }
241 };
242
243
244 class ThreadInVMfromNative : public ThreadStateTransition {
245 public:
246 ThreadInVMfromNative(JavaThread* thread) : ThreadStateTransition(thread) {
247 trans_from_native(_thread_in_vm);
248 }
249 ~ThreadInVMfromNative() {
250 trans_and_fence(_thread_in_vm, _thread_in_native);
251 }
252 };
253
254
255 class ThreadToNativeFromVM : public ThreadStateTransition {
256 public:
257 ThreadToNativeFromVM(JavaThread *thread) : ThreadStateTransition(thread) {
258 // We are leaving the VM at this point and going directly to native code.
259 // Block, if we are in the middle of a safepoint synchronization.
260 assert(!thread->owns_locks(), "must release all locks when leaving VM");
261 thread->frame_anchor()->make_walkable(thread);
262 trans_and_fence(_thread_in_vm, _thread_in_native);
263 // Check for pending. async. exceptions or suspends.
264 if (_thread->has_special_runtime_exit_condition()) _thread->handle_special_runtime_exit_condition(false);
265 }
266
267 ~ThreadToNativeFromVM() {
268 trans_from_native(_thread_in_vm);
269 // We don't need to clear_walkable because it will happen automagically when we return to java
270 }
271 };
272
273
274 class ThreadBlockInVM : public ThreadStateTransition {
275 public:
276 ThreadBlockInVM(JavaThread *thread)
277 : ThreadStateTransition(thread) {
278 // Once we are blocked vm expects stack to be walkable
279 thread->frame_anchor()->make_walkable(thread);
280 trans_and_fence(_thread_in_vm, _thread_blocked);
281 }
282 ~ThreadBlockInVM() {
283 trans_and_fence(_thread_blocked, _thread_in_vm);
284 // We don't need to clear_walkable because it will happen automagically when we return to java
285 }
286 };
287
288
289 // This special transition class is only used to prevent asynchronous exceptions
290 // from being installed on vm exit in situations where we can't tolerate them.
291 // See bugs: 4324348, 4854693, 4998314, 5040492, 5050705.
292 class ThreadInVMfromJavaNoAsyncException : public ThreadStateTransition {
293 public:
294 ThreadInVMfromJavaNoAsyncException(JavaThread* thread) : ThreadStateTransition(thread) {
295 trans_from_java(_thread_in_vm);
296 }
297 ~ThreadInVMfromJavaNoAsyncException() {
298 trans(_thread_in_vm, _thread_in_Java);
299 // NOTE: We do not check for pending. async. exceptions.
300 // If we did and moved the pending async exception over into the
301 // pending exception field, we would need to deopt (currently C2
302 // only). However, to do so would require that we transition back
303 // to the _thread_in_vm state. Instead we postpone the handling of
304 // the async exception.
305
306 // Check for pending. suspends only.
307 if (_thread->has_special_runtime_exit_condition())
308 _thread->handle_special_runtime_exit_condition(false);
309 }
310 };
311
312 // Debug class instantiated in JRT_ENTRY and ITR_ENTRY macro.
313 // Can be used to verify properties on enter/exit of the VM.
314
315 #ifdef ASSERT
316 class VMEntryWrapper {
317 public:
318 VMEntryWrapper() {
319 if (VerifyLastFrame) {
320 InterfaceSupport::verify_last_frame();
321 }
322 }
323
324 ~VMEntryWrapper() {
325 InterfaceSupport::check_gc_alot();
326 if (WalkStackALot) {
327 InterfaceSupport::walk_stack();
328 }
329 #ifdef ENABLE_ZAP_DEAD_LOCALS
330 if (ZapDeadLocalsOld) {
331 InterfaceSupport::zap_dead_locals_old();
332 }
333 #endif
334 #ifdef COMPILER2
335 // This option is not used by Compiler 1
336 if (StressDerivedPointers) {
337 InterfaceSupport::stress_derived_pointers();
338 }
339 #endif
340 if (DeoptimizeALot || DeoptimizeRandom) {
341 InterfaceSupport::deoptimizeAll();
342 }
343 if (ZombieALot) {
344 InterfaceSupport::zombieAll();
345 }
346 // do verification AFTER potential deoptimization
347 if (VerifyStack) {
348 InterfaceSupport::verify_stack();
349 }
350
351 }
352 };
353
354
355 class VMNativeEntryWrapper {
356 public:
357 VMNativeEntryWrapper() {
358 if (GCALotAtAllSafepoints) InterfaceSupport::check_gc_alot();
359 }
360
361 ~VMNativeEntryWrapper() {
362 if (GCALotAtAllSafepoints) InterfaceSupport::check_gc_alot();
363 }
364 };
365
366 #endif
367
368
369 // VM-internal runtime interface support
370
371 #ifdef ASSERT
372
373 class RuntimeHistogramElement : public HistogramElement {
374 public:
375 RuntimeHistogramElement(const char* name);
376 };
377
378 #define TRACE_CALL(result_type, header) \
379 InterfaceSupport::_number_of_calls++; \
380 if (TraceRuntimeCalls) \
381 InterfaceSupport::trace(#result_type, #header); \
382 if (CountRuntimeCalls) { \
383 static RuntimeHistogramElement* e = new RuntimeHistogramElement(#header); \
384 if (e != NULL) e->increment_count(); \
385 }
386 #else
387 #define TRACE_CALL(result_type, header) \
388 /* do nothing */
389 #endif
390
391
392 // LEAF routines do not lock, GC or throw exceptions
393
394 #define __LEAF(result_type, header) \
395 TRACE_CALL(result_type, header) \
396 debug_only(NoHandleMark __hm;) \
397 /* begin of body */
398
399
400 // ENTRY routines may lock, GC and throw exceptions
401
402 #define __ENTRY(result_type, header, thread) \
403 TRACE_CALL(result_type, header) \
404 HandleMarkCleaner __hm(thread); \
405 Thread* THREAD = thread; \
406 /* begin of body */
407
408
409 // QUICK_ENTRY routines behave like ENTRY but without a handle mark
410
411 #define __QUICK_ENTRY(result_type, header, thread) \
412 TRACE_CALL(result_type, header) \
413 debug_only(NoHandleMark __hm;) \
414 Thread* THREAD = thread; \
415 /* begin of body */
416
417
418 // Definitions for IRT (Interpreter Runtime)
419 // (thread is an argument passed in to all these routines)
420
421 #define IRT_ENTRY(result_type, header) \
422 result_type header { \
423 ThreadInVMfromJava __tiv(thread); \
424 __ENTRY(result_type, header, thread) \
425 debug_only(VMEntryWrapper __vew;)
426
427
428 #define IRT_LEAF(result_type, header) \
429 result_type header { \
430 __LEAF(result_type, header) \
431 debug_only(No_Safepoint_Verifier __nspv(true);)
432
433
434 #define IRT_ENTRY_NO_ASYNC(result_type, header) \
435 result_type header { \
436 ThreadInVMfromJavaNoAsyncException __tiv(thread); \
437 __ENTRY(result_type, header, thread) \
438 debug_only(VMEntryWrapper __vew;)
439
440 // Another special case for nmethod_entry_point so the nmethod that the
441 // interpreter is about to branch to doesn't get flushed before as we
442 // branch to it's interpreter_entry_point. Skip stress testing here too.
443 // Also we don't allow async exceptions because it is just too painful.
444 #define IRT_ENTRY_FOR_NMETHOD(result_type, header) \
445 result_type header { \
446 nmethodLocker _nmlock(nm); \
447 ThreadInVMfromJavaNoAsyncException __tiv(thread); \
448 __ENTRY(result_type, header, thread)
449
450 #define IRT_END }
451
452
453 // Definitions for JRT (Java (Compiler/Shared) Runtime)
454
455 #define JRT_ENTRY(result_type, header) \
456 result_type header { \
457 ThreadInVMfromJava __tiv(thread); \
458 __ENTRY(result_type, header, thread) \
459 debug_only(VMEntryWrapper __vew;)
460
461
462 #define JRT_LEAF(result_type, header) \
463 result_type header { \
464 __LEAF(result_type, header) \
465 debug_only(JRT_Leaf_Verifier __jlv;)
466
467
468 #define JRT_ENTRY_NO_ASYNC(result_type, header) \
469 result_type header { \
470 ThreadInVMfromJavaNoAsyncException __tiv(thread); \
471 __ENTRY(result_type, header, thread) \
472 debug_only(VMEntryWrapper __vew;)
473
474 // Same as JRT Entry but allows for return value after the safepoint
475 // to get back into Java from the VM
476 #define JRT_BLOCK_ENTRY(result_type, header) \
477 result_type header { \
478 TRACE_CALL(result_type, header) \
479 HandleMarkCleaner __hm(thread);
480
481 #define JRT_BLOCK \
482 { \
483 ThreadInVMfromJava __tiv(thread); \
484 Thread* THREAD = thread; \
485 debug_only(VMEntryWrapper __vew;)
486
487 #define JRT_BLOCK_END }
488
489 #define JRT_END }
490
491 // Definitions for JNI
492
493 #define JNI_ENTRY(result_type, header) \
494 JNI_ENTRY_NO_PRESERVE(result_type, header) \
495 WeakPreserveExceptionMark __wem(thread);
496
497 #define JNI_ENTRY_NO_PRESERVE(result_type, header) \
498 extern "C" { \
499 result_type JNICALL header { \
500 JavaThread* thread=JavaThread::thread_from_jni_environment(env); \
501 assert( !VerifyJNIEnvThread || (thread == Thread::current()), "JNIEnv is only valid in same thread"); \
502 ThreadInVMfromNative __tiv(thread); \
503 debug_only(VMNativeEntryWrapper __vew;) \
504 __ENTRY(result_type, header, thread)
505
506
507 // Ensure that the VMNativeEntryWrapper constructor, which can cause
508 // a GC, is called outside the NoHandleMark (set via __QUICK_ENTRY).
509 #define JNI_QUICK_ENTRY(result_type, header) \
510 extern "C" { \
511 result_type JNICALL header { \
512 JavaThread* thread=JavaThread::thread_from_jni_environment(env); \
513 assert( !VerifyJNIEnvThread || (thread == Thread::current()), "JNIEnv is only valid in same thread"); \
514 ThreadInVMfromNative __tiv(thread); \
515 debug_only(VMNativeEntryWrapper __vew;) \
516 __QUICK_ENTRY(result_type, header, thread)
517
518
519 #define JNI_LEAF(result_type, header) \
520 extern "C" { \
521 result_type JNICALL header { \
522 JavaThread* thread=JavaThread::thread_from_jni_environment(env); \
523 assert( !VerifyJNIEnvThread || (thread == Thread::current()), "JNIEnv is only valid in same thread"); \
524 __LEAF(result_type, header)
525
526
527 // Close the routine and the extern "C"
528 #define JNI_END } }
529
530
531
532 // Definitions for JVM
533
534 #define JVM_ENTRY(result_type, header) \
535 extern "C" { \
536 result_type JNICALL header { \
537 JavaThread* thread=JavaThread::thread_from_jni_environment(env); \
538 ThreadInVMfromNative __tiv(thread); \
539 debug_only(VMNativeEntryWrapper __vew;) \
540 __ENTRY(result_type, header, thread)
541
542
543 #define JVM_ENTRY_NO_ENV(result_type, header) \
544 extern "C" { \
545 result_type JNICALL header { \
546 JavaThread* thread = (JavaThread*)ThreadLocalStorage::thread(); \
547 ThreadInVMfromNative __tiv(thread); \
548 debug_only(VMNativeEntryWrapper __vew;) \
549 __ENTRY(result_type, header, thread)
550
551
552 #define JVM_QUICK_ENTRY(result_type, header) \
553 extern "C" { \
554 result_type JNICALL header { \
555 JavaThread* thread=JavaThread::thread_from_jni_environment(env); \
556 ThreadInVMfromNative __tiv(thread); \
557 debug_only(VMNativeEntryWrapper __vew;) \
558 __QUICK_ENTRY(result_type, header, thread)
559
560
561 #define JVM_LEAF(result_type, header) \
562 extern "C" { \
563 result_type JNICALL header { \
564 VM_Exit::block_if_vm_exited(); \
565 __LEAF(result_type, header)
566
567
568 #define JVM_END } }