1 /*
2 * Copyright (c) 2015, 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 #include "precompiled.hpp"
26 #include "code/compiledIC.hpp"
27 #include "code/compiledMethod.inline.hpp"
28 #include "code/exceptionHandlerTable.hpp"
29 #include "code/scopeDesc.hpp"
30 #include "code/codeCache.hpp"
31 #include "code/icBuffer.hpp"
32 #include "gc/shared/barrierSet.hpp"
33 #include "gc/shared/barrierSetNMethod.hpp"
34 #include "gc/shared/gcBehaviours.hpp"
35 #include "interpreter/bytecode.inline.hpp"
36 #include "logging/log.hpp"
37 #include "logging/logTag.hpp"
38 #include "memory/resourceArea.hpp"
39 #include "oops/methodData.hpp"
40 #include "oops/method.inline.hpp"
41 #include "prims/methodHandles.hpp"
42 #include "runtime/atomic.hpp"
43 #include "runtime/deoptimization.hpp"
44 #include "runtime/handles.inline.hpp"
45 #include "runtime/mutexLocker.hpp"
46 #include "runtime/sharedRuntime.hpp"
47
48 CompiledMethod::CompiledMethod(Method* method, const char* name, CompilerType type, const CodeBlobLayout& layout,
49 int frame_complete_offset, int frame_size, ImmutableOopMapSet* oop_maps,
50 bool caller_must_gc_arguments)
51 : CodeBlob(name, type, layout, frame_complete_offset, frame_size, oop_maps, caller_must_gc_arguments),
52 _mark_for_deoptimization_status(not_marked),
53 _method(method),
54 _gc_data(NULL)
55 {
56 init_defaults();
57 }
58
59 CompiledMethod::CompiledMethod(Method* method, const char* name, CompilerType type, int size,
60 int header_size, CodeBuffer* cb, int frame_complete_offset, int frame_size,
61 OopMapSet* oop_maps, bool caller_must_gc_arguments)
62 : CodeBlob(name, type, CodeBlobLayout((address) this, size, header_size, cb), cb,
63 frame_complete_offset, frame_size, oop_maps, caller_must_gc_arguments),
64 _mark_for_deoptimization_status(not_marked),
65 _method(method),
66 _gc_data(NULL)
67 {
68 init_defaults();
69 }
70
71 void CompiledMethod::init_defaults() {
72 { // avoid uninitialized fields, even for short time periods
73 _is_far_code = false;
74 _scopes_data_begin = NULL;
75 _deopt_handler_begin = NULL;
76 _deopt_mh_handler_begin = NULL;
77 _exception_cache = NULL;
78 }
79 _has_unsafe_access = 0;
80 _has_method_handle_invokes = 0;
81 _lazy_critical_native = 0;
82 _has_wide_vectors = 0;
83 }
84
85 bool CompiledMethod::is_method_handle_return(address return_pc) {
86 if (!has_method_handle_invokes()) return false;
87 PcDesc* pd = pc_desc_at(return_pc);
88 if (pd == NULL)
89 return false;
90 return pd->is_method_handle_invoke();
91 }
92
93 // Returns a string version of the method state.
94 const char* CompiledMethod::state() const {
95 int state = get_state();
96 switch (state) {
97 case not_installed:
98 return "not installed";
99 case in_use:
100 return "in use";
101 case not_used:
102 return "not_used";
103 case not_entrant:
104 return "not_entrant";
105 case zombie:
106 return "zombie";
107 case unloaded:
108 return "unloaded";
109 default:
110 fatal("unexpected method state: %d", state);
111 return NULL;
112 }
113 }
114
115 //-----------------------------------------------------------------------------
116 void CompiledMethod::mark_for_deoptimization(bool inc_recompile_counts) {
117 MutexLocker ml(CompiledMethod_lock->owned_by_self() ? NULL : CompiledMethod_lock,
118 Mutex::_no_safepoint_check_flag);
119 _mark_for_deoptimization_status = (inc_recompile_counts ? deoptimize : deoptimize_noupdate);
120 }
121
122 //-----------------------------------------------------------------------------
123
124 ExceptionCache* CompiledMethod::exception_cache_acquire() const {
125 return Atomic::load_acquire(&_exception_cache);
126 }
127
128 void CompiledMethod::add_exception_cache_entry(ExceptionCache* new_entry) {
129 assert(ExceptionCache_lock->owned_by_self(),"Must hold the ExceptionCache_lock");
130 assert(new_entry != NULL,"Must be non null");
131 assert(new_entry->next() == NULL, "Must be null");
132
133 for (;;) {
134 ExceptionCache *ec = exception_cache();
135 if (ec != NULL) {
136 Klass* ex_klass = ec->exception_type();
137 if (!ex_klass->is_loader_alive()) {
138 // We must guarantee that entries are not inserted with new next pointer
139 // edges to ExceptionCache entries with dead klasses, due to bad interactions
140 // with concurrent ExceptionCache cleanup. Therefore, the inserts roll
141 // the head pointer forward to the first live ExceptionCache, so that the new
142 // next pointers always point at live ExceptionCaches, that are not removed due
143 // to concurrent ExceptionCache cleanup.
144 ExceptionCache* next = ec->next();
145 if (Atomic::cmpxchg(&_exception_cache, ec, next) == ec) {
146 CodeCache::release_exception_cache(ec);
147 }
148 continue;
149 }
150 ec = exception_cache();
151 if (ec != NULL) {
152 new_entry->set_next(ec);
153 }
154 }
155 if (Atomic::cmpxchg(&_exception_cache, ec, new_entry) == ec) {
156 return;
157 }
158 }
159 }
160
161 void CompiledMethod::clean_exception_cache() {
162 // For each nmethod, only a single thread may call this cleanup function
163 // at the same time, whether called in STW cleanup or concurrent cleanup.
164 // Note that if the GC is processing exception cache cleaning in a concurrent phase,
165 // then a single writer may contend with cleaning up the head pointer to the
166 // first ExceptionCache node that has a Klass* that is alive. That is fine,
167 // as long as there is no concurrent cleanup of next pointers from concurrent writers.
168 // And the concurrent writers do not clean up next pointers, only the head.
169 // Also note that concurent readers will walk through Klass* pointers that are not
170 // alive. That does not cause ABA problems, because Klass* is deleted after
171 // a handshake with all threads, after all stale ExceptionCaches have been
172 // unlinked. That is also when the CodeCache::exception_cache_purge_list()
173 // is deleted, with all ExceptionCache entries that were cleaned concurrently.
174 // That similarly implies that CAS operations on ExceptionCache entries do not
175 // suffer from ABA problems as unlinking and deletion is separated by a global
176 // handshake operation.
177 ExceptionCache* prev = NULL;
178 ExceptionCache* curr = exception_cache_acquire();
179
180 while (curr != NULL) {
181 ExceptionCache* next = curr->next();
182
183 if (!curr->exception_type()->is_loader_alive()) {
184 if (prev == NULL) {
185 // Try to clean head; this is contended by concurrent inserts, that
186 // both lazily clean the head, and insert entries at the head. If
187 // the CAS fails, the operation is restarted.
188 if (Atomic::cmpxchg(&_exception_cache, curr, next) != curr) {
189 prev = NULL;
190 curr = exception_cache_acquire();
191 continue;
192 }
193 } else {
194 // It is impossible to during cleanup connect the next pointer to
195 // an ExceptionCache that has not been published before a safepoint
196 // prior to the cleanup. Therefore, release is not required.
197 prev->set_next(next);
198 }
199 // prev stays the same.
200
201 CodeCache::release_exception_cache(curr);
202 } else {
203 prev = curr;
204 }
205
206 curr = next;
207 }
208 }
209
210 // public method for accessing the exception cache
211 // These are the public access methods.
212 address CompiledMethod::handler_for_exception_and_pc(Handle exception, address pc) {
213 // We never grab a lock to read the exception cache, so we may
214 // have false negatives. This is okay, as it can only happen during
215 // the first few exception lookups for a given nmethod.
216 ExceptionCache* ec = exception_cache_acquire();
217 while (ec != NULL) {
218 address ret_val;
219 if ((ret_val = ec->match(exception,pc)) != NULL) {
220 return ret_val;
221 }
222 ec = ec->next();
223 }
224 return NULL;
225 }
226
227 void CompiledMethod::add_handler_for_exception_and_pc(Handle exception, address pc, address handler) {
228 // There are potential race conditions during exception cache updates, so we
229 // must own the ExceptionCache_lock before doing ANY modifications. Because
230 // we don't lock during reads, it is possible to have several threads attempt
231 // to update the cache with the same data. We need to check for already inserted
232 // copies of the current data before adding it.
233
234 MutexLocker ml(ExceptionCache_lock);
235 ExceptionCache* target_entry = exception_cache_entry_for_exception(exception);
236
237 if (target_entry == NULL || !target_entry->add_address_and_handler(pc,handler)) {
238 target_entry = new ExceptionCache(exception,pc,handler);
239 add_exception_cache_entry(target_entry);
240 }
241 }
242
243 // private method for handling exception cache
244 // These methods are private, and used to manipulate the exception cache
245 // directly.
246 ExceptionCache* CompiledMethod::exception_cache_entry_for_exception(Handle exception) {
247 ExceptionCache* ec = exception_cache_acquire();
248 while (ec != NULL) {
249 if (ec->match_exception_with_space(exception)) {
250 return ec;
251 }
252 ec = ec->next();
253 }
254 return NULL;
255 }
256
257 //-------------end of code for ExceptionCache--------------
258
259 bool CompiledMethod::is_at_poll_return(address pc) {
260 RelocIterator iter(this, pc, pc+1);
261 while (iter.next()) {
262 if (iter.type() == relocInfo::poll_return_type)
263 return true;
264 }
265 return false;
266 }
267
268
269 bool CompiledMethod::is_at_poll_or_poll_return(address pc) {
270 RelocIterator iter(this, pc, pc+1);
271 while (iter.next()) {
272 relocInfo::relocType t = iter.type();
273 if (t == relocInfo::poll_return_type || t == relocInfo::poll_type)
274 return true;
275 }
276 return false;
277 }
278
279 void CompiledMethod::verify_oop_relocations() {
280 // Ensure sure that the code matches the current oop values
281 RelocIterator iter(this, NULL, NULL);
282 while (iter.next()) {
283 if (iter.type() == relocInfo::oop_type) {
284 oop_Relocation* reloc = iter.oop_reloc();
285 if (!reloc->oop_is_immediate()) {
286 reloc->verify_oop_relocation();
287 }
288 }
289 }
290 }
291
292
293 ScopeDesc* CompiledMethod::scope_desc_at(address pc) {
294 PcDesc* pd = pc_desc_at(pc);
295 guarantee(pd != NULL, "scope must be present");
296 return new ScopeDesc(this, pd->scope_decode_offset(),
297 pd->obj_decode_offset(), pd->should_reexecute(), pd->rethrow_exception(),
298 pd->return_oop());
299 }
300
301 ScopeDesc* CompiledMethod::scope_desc_near(address pc) {
302 PcDesc* pd = pc_desc_near(pc);
303 guarantee(pd != NULL, "scope must be present");
304 return new ScopeDesc(this, pd->scope_decode_offset(),
305 pd->obj_decode_offset(), pd->should_reexecute(), pd->rethrow_exception(),
306 pd->return_oop());
307 }
308
309 address CompiledMethod::oops_reloc_begin() const {
310 // If the method is not entrant or zombie then a JMP is plastered over the
311 // first few bytes. If an oop in the old code was there, that oop
312 // should not get GC'd. Skip the first few bytes of oops on
313 // not-entrant methods.
314 if (frame_complete_offset() != CodeOffsets::frame_never_safe &&
315 code_begin() + frame_complete_offset() >
316 verified_entry_point() + NativeJump::instruction_size)
317 {
318 // If we have a frame_complete_offset after the native jump, then there
319 // is no point trying to look for oops before that. This is a requirement
320 // for being allowed to scan oops concurrently.
321 return code_begin() + frame_complete_offset();
322 }
323
324 // It is not safe to read oops concurrently using entry barriers, if their
325 // location depend on whether the nmethod is entrant or not.
326 assert(BarrierSet::barrier_set()->barrier_set_nmethod() == NULL, "Not safe oop scan");
327
328 address low_boundary = verified_entry_point();
329 if (!is_in_use() && is_nmethod()) {
330 low_boundary += NativeJump::instruction_size;
331 // %%% Note: On SPARC we patch only a 4-byte trap, not a full NativeJump.
332 // This means that the low_boundary is going to be a little too high.
333 // This shouldn't matter, since oops of non-entrant methods are never used.
334 // In fact, why are we bothering to look at oops in a non-entrant method??
335 }
336 return low_boundary;
337 }
338
339 int CompiledMethod::verify_icholder_relocations() {
340 ResourceMark rm;
341 int count = 0;
342
343 RelocIterator iter(this);
344 while(iter.next()) {
345 if (iter.type() == relocInfo::virtual_call_type) {
346 if (CompiledIC::is_icholder_call_site(iter.virtual_call_reloc(), this)) {
347 CompiledIC *ic = CompiledIC_at(&iter);
348 if (TraceCompiledIC) {
349 tty->print("noticed icholder " INTPTR_FORMAT " ", p2i(ic->cached_icholder()));
350 ic->print();
351 }
352 assert(ic->cached_icholder() != NULL, "must be non-NULL");
353 count++;
354 }
355 }
356 }
357
358 return count;
359 }
360
361 // Method that knows how to preserve outgoing arguments at call. This method must be
362 // called with a frame corresponding to a Java invoke
363 void CompiledMethod::preserve_callee_argument_oops(frame fr, const RegisterMap *reg_map, OopClosure* f) {
364 if (method() != NULL && !method()->is_native()) {
365 address pc = fr.pc();
366 SimpleScopeDesc ssd(this, pc);
367 Bytecode_invoke call(methodHandle(Thread::current(), ssd.method()), ssd.bci());
368 bool has_receiver = call.has_receiver();
369 bool has_appendix = call.has_appendix();
370 Symbol* signature = call.signature();
371
372 // The method attached by JIT-compilers should be used, if present.
373 // Bytecode can be inaccurate in such case.
374 Method* callee = attached_method_before_pc(pc);
375 if (callee != NULL) {
376 has_receiver = !(callee->access_flags().is_static());
377 has_appendix = false;
378 signature = callee->signature();
379 }
380
381 fr.oops_compiled_arguments_do(signature, has_receiver, has_appendix, reg_map, f);
382 }
383 }
384
385 Method* CompiledMethod::attached_method(address call_instr) {
386 assert(code_contains(call_instr), "not part of the nmethod");
387 RelocIterator iter(this, call_instr, call_instr + 1);
388 while (iter.next()) {
389 if (iter.addr() == call_instr) {
390 switch(iter.type()) {
391 case relocInfo::static_call_type: return iter.static_call_reloc()->method_value();
392 case relocInfo::opt_virtual_call_type: return iter.opt_virtual_call_reloc()->method_value();
393 case relocInfo::virtual_call_type: return iter.virtual_call_reloc()->method_value();
394 default: break;
395 }
396 }
397 }
398 return NULL; // not found
399 }
400
401 Method* CompiledMethod::attached_method_before_pc(address pc) {
402 if (NativeCall::is_call_before(pc)) {
403 NativeCall* ncall = nativeCall_before(pc);
404 return attached_method(ncall->instruction_address());
405 }
406 return NULL; // not a call
407 }
408
409 void CompiledMethod::clear_inline_caches() {
410 assert(SafepointSynchronize::is_at_safepoint(), "cleaning of IC's only allowed at safepoint");
411 if (is_zombie()) {
412 return;
413 }
414
415 RelocIterator iter(this);
416 while (iter.next()) {
417 iter.reloc()->clear_inline_cache();
418 }
419 }
420
421 // Clear IC callsites, releasing ICStubs of all compiled ICs
422 // as well as any associated CompiledICHolders.
423 void CompiledMethod::clear_ic_callsites() {
424 assert(CompiledICLocker::is_safe(this), "mt unsafe call");
425 ResourceMark rm;
426 RelocIterator iter(this);
427 while(iter.next()) {
428 if (iter.type() == relocInfo::virtual_call_type) {
429 CompiledIC* ic = CompiledIC_at(&iter);
430 ic->set_to_clean(false);
431 }
432 }
433 }
434
435 #ifdef ASSERT
436 // Check class_loader is alive for this bit of metadata.
437 class CheckClass : public MetadataClosure {
438 void do_metadata(Metadata* md) {
439 Klass* klass = NULL;
440 if (md->is_klass()) {
441 klass = ((Klass*)md);
442 } else if (md->is_method()) {
443 klass = ((Method*)md)->method_holder();
444 } else if (md->is_methodData()) {
445 klass = ((MethodData*)md)->method()->method_holder();
446 } else {
447 md->print();
448 ShouldNotReachHere();
449 }
450 assert(klass->is_loader_alive(), "must be alive");
451 }
452 };
453 #endif // ASSERT
454
455
456 bool CompiledMethod::clean_ic_if_metadata_is_dead(CompiledIC *ic) {
457 if (ic->is_clean()) {
458 return true;
459 }
460 if (ic->is_icholder_call()) {
461 // The only exception is compiledICHolder metdata which may
462 // yet be marked below. (We check this further below).
463 CompiledICHolder* cichk_metdata = ic->cached_icholder();
464
465 if (cichk_metdata->is_loader_alive()) {
466 return true;
467 }
468 } else {
469 Metadata* ic_metdata = ic->cached_metadata();
470 if (ic_metdata != NULL) {
471 if (ic_metdata->is_klass()) {
472 if (((Klass*)ic_metdata)->is_loader_alive()) {
473 return true;
474 }
475 } else if (ic_metdata->is_method()) {
476 Method* method = (Method*)ic_metdata;
477 assert(!method->is_old(), "old method should have been cleaned");
478 if (method->method_holder()->is_loader_alive()) {
479 return true;
480 }
481 } else {
482 ShouldNotReachHere();
483 }
484 }
485 }
486
487 return ic->set_to_clean();
488 }
489
490 // Clean references to unloaded nmethods at addr from this one, which is not unloaded.
491 template <class CompiledICorStaticCall>
492 static bool clean_if_nmethod_is_unloaded(CompiledICorStaticCall *ic, address addr, CompiledMethod* from,
493 bool clean_all) {
494 // Ok, to lookup references to zombies here
495 CodeBlob *cb = CodeCache::find_blob_unsafe(addr);
496 CompiledMethod* nm = (cb != NULL) ? cb->as_compiled_method_or_null() : NULL;
497 if (nm != NULL) {
498 // Clean inline caches pointing to both zombie and not_entrant methods
499 if (clean_all || !nm->is_in_use() || nm->is_unloading() || (nm->method()->code() != nm)) {
500 // Inline cache cleaning should only be initiated on CompiledMethods that have been
501 // observed to be is_alive(). However, with concurrent code cache unloading, it is
502 // possible that by now, the state has become !is_alive. This can happen in two ways:
503 // 1) It can be racingly flipped to unloaded if the nmethod // being cleaned (from the
504 // sweeper) is_unloading(). This is fine, because if that happens, then the inline
505 // caches have already been cleaned under the same CompiledICLocker that we now hold during
506 // inline cache cleaning, and we will simply walk the inline caches again, and likely not
507 // find much of interest to clean. However, this race prevents us from asserting that the
508 // nmethod is_alive(). The is_unloading() function is completely monotonic; once set due
509 // to an oop dying, it remains set forever until freed. Because of that, all unloaded
510 // nmethods are is_unloading(), but notably, an unloaded nmethod may also subsequently
511 // become zombie (when the sweeper converts it to zombie).
512 // 2) It can be racingly flipped to zombie if the nmethod being cleaned (by the concurrent
513 // GC) cleans a zombie nmethod that is concurrently made zombie by the sweeper. In this
514 // scenario, the sweeper will first transition the nmethod to zombie, and then when
515 // unregistering from the GC, it will wait until the GC is done. The GC will then clean
516 // the inline caches *with IC stubs*, even though no IC stubs are needed. This is fine,
517 // as long as the IC stubs are guaranteed to be released until the next safepoint, where
518 // IC finalization requires live IC stubs to not be associated with zombie nmethods.
519 // This is guaranteed, because the sweeper does not have a single safepoint check until
520 // after it completes the whole transition function; it will wake up after the GC is
521 // done with concurrent code cache cleaning (which blocks out safepoints using the
522 // suspendible threads set), and then call clear_ic_callsites, which will release the
523 // associated IC stubs, before a subsequent safepoint poll can be reached. This
524 // guarantees that the spuriously created IC stubs are released appropriately before
525 // IC finalization in a safepoint gets to run. Therefore, this race is fine. This is also
526 // valid in a scenario where an inline cache of a zombie nmethod gets a spurious IC stub,
527 // and then when cleaning another inline cache, fails to request an IC stub because we
528 // exhausted the IC stub buffer. In this scenario, the GC will request a safepoint after
529 // yielding the suspendible therad set, effectively unblocking safepoints. Before such
530 // a safepoint can be reached, the sweeper similarly has to wake up, clear the IC stubs,
531 // and reach the next safepoint poll, after the whole transition function has completed.
532 // Due to the various races that can cause an nmethod to first be is_alive() and then
533 // racingly become !is_alive(), it is unfortunately not possible to assert the nmethod
534 // is_alive(), !is_unloaded() or !is_zombie() here.
535 if (!ic->set_to_clean(!from->is_unloading())) {
536 return false;
537 }
538 assert(ic->is_clean(), "nmethod " PTR_FORMAT "not clean %s", p2i(from), from->method()->name_and_sig_as_C_string());
539 }
540 }
541 return true;
542 }
543
544 static bool clean_if_nmethod_is_unloaded(CompiledIC *ic, CompiledMethod* from,
545 bool clean_all) {
546 return clean_if_nmethod_is_unloaded(ic, ic->ic_destination(), from, clean_all);
547 }
548
549 static bool clean_if_nmethod_is_unloaded(CompiledStaticCall *csc, CompiledMethod* from,
550 bool clean_all) {
551 return clean_if_nmethod_is_unloaded(csc, csc->destination(), from, clean_all);
552 }
553
554 // Cleans caches in nmethods that point to either classes that are unloaded
555 // or nmethods that are unloaded.
556 //
557 // Can be called either in parallel by G1 currently or after all
558 // nmethods are unloaded. Return postponed=true in the parallel case for
559 // inline caches found that point to nmethods that are not yet visited during
560 // the do_unloading walk.
561 bool CompiledMethod::unload_nmethod_caches(bool unloading_occurred) {
562 ResourceMark rm;
563
564 // Exception cache only needs to be called if unloading occurred
565 if (unloading_occurred) {
566 clean_exception_cache();
567 }
568
569 if (!cleanup_inline_caches_impl(unloading_occurred, false)) {
570 return false;
571 }
572
573 #ifdef ASSERT
574 // Check that the metadata embedded in the nmethod is alive
575 CheckClass check_class;
576 metadata_do(&check_class);
577 #endif
578 return true;
579 }
580
581 void CompiledMethod::run_nmethod_entry_barrier() {
582 BarrierSetNMethod* bs_nm = BarrierSet::barrier_set()->barrier_set_nmethod();
583 if (bs_nm != NULL) {
584 // We want to keep an invariant that nmethods found through iterations of a Thread's
585 // nmethods found in safepoints have gone through an entry barrier and are not armed.
586 // By calling this nmethod entry barrier, it plays along and acts
587 // like any other nmethod found on the stack of a thread (fewer surprises).
588 nmethod* nm = as_nmethod_or_null();
589 if (nm != NULL) {
590 bool alive = bs_nm->nmethod_entry_barrier(nm);
591 assert(alive, "should be alive");
592 }
593 }
594 }
595
596 void CompiledMethod::cleanup_inline_caches(bool clean_all) {
597 for (;;) {
598 ICRefillVerifier ic_refill_verifier;
599 { CompiledICLocker ic_locker(this);
600 if (cleanup_inline_caches_impl(false, clean_all)) {
601 return;
602 }
603 }
604 // Call this nmethod entry barrier from the sweeper.
605 run_nmethod_entry_barrier();
606 InlineCacheBuffer::refill_ic_stubs();
607 }
608 }
609
610 // Called to clean up after class unloading for live nmethods and from the sweeper
611 // for all methods.
612 bool CompiledMethod::cleanup_inline_caches_impl(bool unloading_occurred, bool clean_all) {
613 assert(CompiledICLocker::is_safe(this), "mt unsafe call");
614 ResourceMark rm;
615
616 // Find all calls in an nmethod and clear the ones that point to non-entrant,
617 // zombie and unloaded nmethods.
618 RelocIterator iter(this, oops_reloc_begin());
619 bool is_in_static_stub = false;
620 while(iter.next()) {
621
622 switch (iter.type()) {
623
624 case relocInfo::virtual_call_type:
625 if (unloading_occurred) {
626 // If class unloading occurred we first clear ICs where the cached metadata
627 // is referring to an unloaded klass or method.
628 if (!clean_ic_if_metadata_is_dead(CompiledIC_at(&iter))) {
629 return false;
630 }
631 }
632
633 if (!clean_if_nmethod_is_unloaded(CompiledIC_at(&iter), this, clean_all)) {
634 return false;
635 }
636 break;
637
638 case relocInfo::opt_virtual_call_type:
639 if (!clean_if_nmethod_is_unloaded(CompiledIC_at(&iter), this, clean_all)) {
640 return false;
641 }
642 break;
643
644 case relocInfo::static_call_type:
645 if (!clean_if_nmethod_is_unloaded(compiledStaticCall_at(iter.reloc()), this, clean_all)) {
646 return false;
647 }
648 break;
649
650 case relocInfo::static_stub_type: {
651 is_in_static_stub = true;
652 break;
653 }
654
655 case relocInfo::metadata_type: {
656 // Only the metadata relocations contained in static/opt virtual call stubs
657 // contains the Method* passed to c2i adapters. It is the only metadata
658 // relocation that needs to be walked, as it is the one metadata relocation
659 // that violates the invariant that all metadata relocations have an oop
660 // in the compiled method (due to deferred resolution and code patching).
661
662 // This causes dead metadata to remain in compiled methods that are not
663 // unloading. Unless these slippery metadata relocations of the static
664 // stubs are at least cleared, subsequent class redefinition operations
665 // will access potentially free memory, and JavaThread execution
666 // concurrent to class unloading may call c2i adapters with dead methods.
667 if (!is_in_static_stub) {
668 // The first metadata relocation after a static stub relocation is the
669 // metadata relocation of the static stub used to pass the Method* to
670 // c2i adapters.
671 continue;
672 }
673 is_in_static_stub = false;
674 if (is_unloading()) {
675 // If the nmethod itself is dying, then it may point at dead metadata.
676 // Nobody should follow that metadata; it is strictly unsafe.
677 continue;
678 }
679 metadata_Relocation* r = iter.metadata_reloc();
680 Metadata* md = r->metadata_value();
681 if (md != NULL && md->is_method()) {
682 Method* method = static_cast<Method*>(md);
683 if (!method->method_holder()->is_loader_alive()) {
684 Atomic::store(r->metadata_addr(), (Method*)NULL);
685
686 if (!r->metadata_is_immediate()) {
687 r->fix_metadata_relocation();
688 }
689 }
690 }
691 break;
692 }
693
694 default:
695 break;
696 }
697 }
698
699 return true;
700 }
701
702 address CompiledMethod::continuation_for_implicit_exception(address pc, bool for_div0_check) {
703 // Exception happened outside inline-cache check code => we are inside
704 // an active nmethod => use cpc to determine a return address
705 int exception_offset = pc - code_begin();
706 int cont_offset = ImplicitExceptionTable(this).continuation_offset( exception_offset );
707 #ifdef ASSERT
708 if (cont_offset == 0) {
709 Thread* thread = Thread::current();
710 ResetNoHandleMark rnm; // Might be called from LEAF/QUICK ENTRY
711 HandleMark hm(thread);
712 ResourceMark rm(thread);
713 CodeBlob* cb = CodeCache::find_blob(pc);
714 assert(cb != NULL && cb == this, "");
715 ttyLocker ttyl;
716 tty->print_cr("implicit exception happened at " INTPTR_FORMAT, p2i(pc));
717 print();
718 method()->print_codes();
719 print_code();
720 print_pcs();
721 }
722 #endif
723 if (cont_offset == 0) {
724 // Let the normal error handling report the exception
725 return NULL;
726 }
727 if (cont_offset == exception_offset) {
728 #if INCLUDE_JVMCI
729 Deoptimization::DeoptReason deopt_reason = for_div0_check ? Deoptimization::Reason_div0_check : Deoptimization::Reason_null_check;
730 JavaThread *thread = JavaThread::current();
731 thread->set_jvmci_implicit_exception_pc(pc);
732 thread->set_pending_deoptimization(Deoptimization::make_trap_request(deopt_reason,
733 Deoptimization::Action_reinterpret));
734 return (SharedRuntime::deopt_blob()->implicit_exception_uncommon_trap());
735 #else
736 ShouldNotReachHere();
737 #endif
738 }
739 return code_begin() + cont_offset;
740 }
741
742 class HasEvolDependency : public MetadataClosure {
743 bool _has_evol_dependency;
744 public:
745 HasEvolDependency() : _has_evol_dependency(false) {}
746 void do_metadata(Metadata* md) {
747 if (md->is_method()) {
748 Method* method = (Method*)md;
749 if (method->is_old()) {
750 _has_evol_dependency = true;
751 }
752 }
753 }
754 bool has_evol_dependency() const { return _has_evol_dependency; }
755 };
756
757 bool CompiledMethod::has_evol_metadata() {
758 // Check the metadata in relocIter and CompiledIC and also deoptimize
759 // any nmethod that has reference to old methods.
760 HasEvolDependency check_evol;
761 metadata_do(&check_evol);
762 if (check_evol.has_evol_dependency() && log_is_enabled(Debug, redefine, class, nmethod)) {
763 ResourceMark rm;
764 log_debug(redefine, class, nmethod)
765 ("Found evol dependency of nmethod %s.%s(%s) compile_id=%d on in nmethod metadata",
766 _method->method_holder()->external_name(),
767 _method->name()->as_C_string(),
768 _method->signature()->as_C_string(),
769 compile_id());
770 }
771 return check_evol.has_evol_dependency();
772 }