1 /*
2 * Copyright (c) 2015, 2022, 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/compiledICHolder.inline.hpp"
40 #include "oops/klass.inline.hpp"
41 #include "oops/methodData.hpp"
42 #include "oops/method.inline.hpp"
43 #include "oops/weakHandle.inline.hpp"
44 #include "prims/methodHandles.hpp"
45 #include "runtime/atomic.hpp"
46 #include "runtime/deoptimization.hpp"
47 #include "runtime/frame.inline.hpp"
48 #include "runtime/jniHandles.inline.hpp"
49 #include "runtime/handles.inline.hpp"
50 #include "runtime/mutexLocker.hpp"
51 #include "runtime/sharedRuntime.hpp"
52
53 CompiledMethod::CompiledMethod(Method* method, const char* name, CompilerType type, const CodeBlobLayout& layout,
54 int frame_complete_offset, int frame_size, ImmutableOopMapSet* oop_maps,
55 bool caller_must_gc_arguments, bool compiled)
56 : CodeBlob(name, type, layout, frame_complete_offset, frame_size, oop_maps, caller_must_gc_arguments, compiled),
57 _mark_for_deoptimization_status(not_marked),
58 _method(method),
59 _gc_data(NULL)
60 {
61 init_defaults();
62 }
63
64 CompiledMethod::CompiledMethod(Method* method, const char* name, CompilerType type, int size,
65 int header_size, CodeBuffer* cb, int frame_complete_offset, int frame_size,
66 OopMapSet* oop_maps, bool caller_must_gc_arguments, bool compiled)
67 : CodeBlob(name, type, CodeBlobLayout((address) this, size, header_size, cb), cb,
68 frame_complete_offset, frame_size, oop_maps, caller_must_gc_arguments, compiled),
69 _mark_for_deoptimization_status(not_marked),
70 _method(method),
71 _gc_data(NULL)
72 {
73 init_defaults();
74 }
75
76 void CompiledMethod::init_defaults() {
77 { // avoid uninitialized fields, even for short time periods
78 _scopes_data_begin = NULL;
79 _deopt_handler_begin = NULL;
80 _deopt_mh_handler_begin = NULL;
81 _exception_cache = NULL;
82 }
83 _has_unsafe_access = 0;
84 _has_method_handle_invokes = 0;
85 _has_wide_vectors = 0;
86 _has_monitors = 0;
87 }
88
89 bool CompiledMethod::is_method_handle_return(address return_pc) {
90 if (!has_method_handle_invokes()) return false;
91 PcDesc* pd = pc_desc_at(return_pc);
92 if (pd == NULL)
93 return false;
94 return pd->is_method_handle_invoke();
95 }
96
97 // Returns a string version of the method state.
98 const char* CompiledMethod::state() const {
99 int state = get_state();
100 switch (state) {
101 case not_installed:
102 return "not installed";
103 case in_use:
104 return "in use";
105 case not_used:
106 return "not_used";
107 case not_entrant:
108 return "not_entrant";
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 // assert(can_be_deoptimized(), ""); // in some places we check before marking, in others not.
118 MutexLocker ml(CompiledMethod_lock->owned_by_self() ? NULL : CompiledMethod_lock,
119 Mutex::_no_safepoint_check_flag);
120 if (_mark_for_deoptimization_status != deoptimize_done) { // can't go backwards
121 _mark_for_deoptimization_status = (inc_recompile_counts ? deoptimize : deoptimize_noupdate);
122 }
123 }
124
125 //-----------------------------------------------------------------------------
126
127 ExceptionCache* CompiledMethod::exception_cache_acquire() const {
128 return Atomic::load_acquire(&_exception_cache);
129 }
130
131 void CompiledMethod::add_exception_cache_entry(ExceptionCache* new_entry) {
132 assert(ExceptionCache_lock->owned_by_self(),"Must hold the ExceptionCache_lock");
133 assert(new_entry != NULL,"Must be non null");
134 assert(new_entry->next() == NULL, "Must be null");
135
136 for (;;) {
137 ExceptionCache *ec = exception_cache();
138 if (ec != NULL) {
139 Klass* ex_klass = ec->exception_type();
140 if (!ex_klass->is_loader_alive()) {
141 // We must guarantee that entries are not inserted with new next pointer
142 // edges to ExceptionCache entries with dead klasses, due to bad interactions
143 // with concurrent ExceptionCache cleanup. Therefore, the inserts roll
144 // the head pointer forward to the first live ExceptionCache, so that the new
145 // next pointers always point at live ExceptionCaches, that are not removed due
146 // to concurrent ExceptionCache cleanup.
147 ExceptionCache* next = ec->next();
148 if (Atomic::cmpxchg(&_exception_cache, ec, next) == ec) {
149 CodeCache::release_exception_cache(ec);
150 }
151 continue;
152 }
153 ec = exception_cache();
154 if (ec != NULL) {
155 new_entry->set_next(ec);
156 }
157 }
158 if (Atomic::cmpxchg(&_exception_cache, ec, new_entry) == ec) {
159 return;
160 }
161 }
162 }
163
164 void CompiledMethod::clean_exception_cache() {
165 // For each nmethod, only a single thread may call this cleanup function
166 // at the same time, whether called in STW cleanup or concurrent cleanup.
167 // Note that if the GC is processing exception cache cleaning in a concurrent phase,
168 // then a single writer may contend with cleaning up the head pointer to the
169 // first ExceptionCache node that has a Klass* that is alive. That is fine,
170 // as long as there is no concurrent cleanup of next pointers from concurrent writers.
171 // And the concurrent writers do not clean up next pointers, only the head.
172 // Also note that concurrent readers will walk through Klass* pointers that are not
173 // alive. That does not cause ABA problems, because Klass* is deleted after
174 // a handshake with all threads, after all stale ExceptionCaches have been
175 // unlinked. That is also when the CodeCache::exception_cache_purge_list()
176 // is deleted, with all ExceptionCache entries that were cleaned concurrently.
177 // That similarly implies that CAS operations on ExceptionCache entries do not
178 // suffer from ABA problems as unlinking and deletion is separated by a global
179 // handshake operation.
180 ExceptionCache* prev = NULL;
181 ExceptionCache* curr = exception_cache_acquire();
182
183 while (curr != NULL) {
184 ExceptionCache* next = curr->next();
185
186 if (!curr->exception_type()->is_loader_alive()) {
187 if (prev == NULL) {
188 // Try to clean head; this is contended by concurrent inserts, that
189 // both lazily clean the head, and insert entries at the head. If
190 // the CAS fails, the operation is restarted.
191 if (Atomic::cmpxchg(&_exception_cache, curr, next) != curr) {
192 prev = NULL;
193 curr = exception_cache_acquire();
194 continue;
195 }
196 } else {
197 // It is impossible to during cleanup connect the next pointer to
198 // an ExceptionCache that has not been published before a safepoint
199 // prior to the cleanup. Therefore, release is not required.
200 prev->set_next(next);
201 }
202 // prev stays the same.
203
204 CodeCache::release_exception_cache(curr);
205 } else {
206 prev = curr;
207 }
208
209 curr = next;
210 }
211 }
212
213 // public method for accessing the exception cache
214 // These are the public access methods.
215 address CompiledMethod::handler_for_exception_and_pc(Handle exception, address pc) {
216 // We never grab a lock to read the exception cache, so we may
217 // have false negatives. This is okay, as it can only happen during
218 // the first few exception lookups for a given nmethod.
219 ExceptionCache* ec = exception_cache_acquire();
220 while (ec != NULL) {
221 address ret_val;
222 if ((ret_val = ec->match(exception,pc)) != NULL) {
223 return ret_val;
224 }
225 ec = ec->next();
226 }
227 return NULL;
228 }
229
230 void CompiledMethod::add_handler_for_exception_and_pc(Handle exception, address pc, address handler) {
231 // There are potential race conditions during exception cache updates, so we
232 // must own the ExceptionCache_lock before doing ANY modifications. Because
233 // we don't lock during reads, it is possible to have several threads attempt
234 // to update the cache with the same data. We need to check for already inserted
235 // copies of the current data before adding it.
236
237 MutexLocker ml(ExceptionCache_lock);
238 ExceptionCache* target_entry = exception_cache_entry_for_exception(exception);
239
240 if (target_entry == NULL || !target_entry->add_address_and_handler(pc,handler)) {
241 target_entry = new ExceptionCache(exception,pc,handler);
242 add_exception_cache_entry(target_entry);
243 }
244 }
245
246 // private method for handling exception cache
247 // These methods are private, and used to manipulate the exception cache
248 // directly.
249 ExceptionCache* CompiledMethod::exception_cache_entry_for_exception(Handle exception) {
250 ExceptionCache* ec = exception_cache_acquire();
251 while (ec != NULL) {
252 if (ec->match_exception_with_space(exception)) {
253 return ec;
254 }
255 ec = ec->next();
256 }
257 return NULL;
258 }
259
260 //-------------end of code for ExceptionCache--------------
261
262 bool CompiledMethod::is_at_poll_return(address pc) {
263 RelocIterator iter(this, pc, pc+1);
264 while (iter.next()) {
265 if (iter.type() == relocInfo::poll_return_type)
266 return true;
267 }
268 return false;
269 }
270
271
272 bool CompiledMethod::is_at_poll_or_poll_return(address pc) {
273 RelocIterator iter(this, pc, pc+1);
274 while (iter.next()) {
275 relocInfo::relocType t = iter.type();
276 if (t == relocInfo::poll_return_type || t == relocInfo::poll_type)
277 return true;
278 }
279 return false;
280 }
281
282 void CompiledMethod::verify_oop_relocations() {
283 // Ensure sure that the code matches the current oop values
284 RelocIterator iter(this, NULL, NULL);
285 while (iter.next()) {
286 if (iter.type() == relocInfo::oop_type) {
287 oop_Relocation* reloc = iter.oop_reloc();
288 if (!reloc->oop_is_immediate()) {
289 reloc->verify_oop_relocation();
290 }
291 }
292 }
293 }
294
295
296 ScopeDesc* CompiledMethod::scope_desc_at(address pc) {
297 PcDesc* pd = pc_desc_at(pc);
298 guarantee(pd != NULL, "scope must be present");
299 return new ScopeDesc(this, pd);
300 }
301
302 ScopeDesc* CompiledMethod::scope_desc_near(address pc) {
303 PcDesc* pd = pc_desc_near(pc);
304 guarantee(pd != NULL, "scope must be present");
305 return new ScopeDesc(this, pd);
306 }
307
308 address CompiledMethod::oops_reloc_begin() const {
309 // If the method is not entrant then a JMP is plastered over the
310 // first few bytes. If an oop in the old code was there, that oop
311 // should not get GC'd. Skip the first few bytes of oops on
312 // not-entrant methods.
313 if (frame_complete_offset() != CodeOffsets::frame_never_safe &&
314 code_begin() + frame_complete_offset() >
315 verified_entry_point() + NativeJump::instruction_size)
316 {
317 // If we have a frame_complete_offset after the native jump, then there
318 // is no point trying to look for oops before that. This is a requirement
319 // for being allowed to scan oops concurrently.
320 return code_begin() + frame_complete_offset();
321 }
322
323 // It is not safe to read oops concurrently using entry barriers, if their
324 // location depend on whether the nmethod is entrant or not.
325 // assert(BarrierSet::barrier_set()->barrier_set_nmethod() == NULL, "Not safe oop scan");
326
327 address low_boundary = verified_entry_point();
328 if (!is_in_use() && is_nmethod()) {
329 low_boundary += NativeJump::instruction_size;
330 // %%% Note: On SPARC we patch only a 4-byte trap, not a full NativeJump.
331 // This means that the low_boundary is going to be a little too high.
332 // This shouldn't matter, since oops of non-entrant methods are never used.
333 // In fact, why are we bothering to look at oops in a non-entrant method??
334 }
335 return low_boundary;
336 }
337
338 int CompiledMethod::verify_icholder_relocations() {
339 ResourceMark rm;
340 int count = 0;
341
342 RelocIterator iter(this);
343 while(iter.next()) {
344 if (iter.type() == relocInfo::virtual_call_type) {
345 if (CompiledIC::is_icholder_call_site(iter.virtual_call_reloc(), this)) {
346 CompiledIC *ic = CompiledIC_at(&iter);
347 if (TraceCompiledIC) {
348 tty->print("noticed icholder " INTPTR_FORMAT " ", p2i(ic->cached_icholder()));
349 ic->print();
350 }
351 assert(ic->cached_icholder() != NULL, "must be non-NULL");
352 count++;
353 }
354 }
355 }
356
357 return count;
358 }
359
360 // Method that knows how to preserve outgoing arguments at call. This method must be
361 // called with a frame corresponding to a Java invoke
362 void CompiledMethod::preserve_callee_argument_oops(frame fr, const RegisterMap *reg_map, OopClosure* f) {
363 if (method() == NULL) {
364 return;
365 }
366
367 // handle the case of an anchor explicitly set in continuation code that doesn't have a callee
368 JavaThread* thread = reg_map->thread();
369 if (thread->has_last_Java_frame() && fr.sp() == thread->last_Java_sp()) {
370 return;
371 }
372
373 if (!method()->is_native()) {
374 address pc = fr.pc();
375 bool has_receiver, has_appendix;
376 Symbol* signature;
377
378 // The method attached by JIT-compilers should be used, if present.
379 // Bytecode can be inaccurate in such case.
380 Method* callee = attached_method_before_pc(pc);
381 if (callee != NULL) {
382 has_receiver = !(callee->access_flags().is_static());
383 has_appendix = false;
384 signature = callee->signature();
385
386 // If inline types are passed as fields, use the extended signature
387 // which contains the types of all (oop) fields of the inline type.
388 if (is_compiled_by_c2() && callee->has_scalarized_args()) {
389 const GrowableArray<SigEntry>* sig = callee->adapter()->get_sig_cc();
390 assert(sig != NULL, "sig should never be null");
391 TempNewSymbol tmp_sig = SigEntry::create_symbol(sig);
392 has_receiver = false; // The extended signature contains the receiver type
393 fr.oops_compiled_arguments_do(tmp_sig, has_receiver, has_appendix, reg_map, f);
394 return;
395 }
396 } else {
397 SimpleScopeDesc ssd(this, pc);
398
399 Bytecode_invoke call(methodHandle(Thread::current(), ssd.method()), ssd.bci());
400 has_receiver = call.has_receiver();
401 has_appendix = call.has_appendix();
402 signature = call.signature();
403 }
404
405 fr.oops_compiled_arguments_do(signature, has_receiver, has_appendix, reg_map, f);
406 } else if (method()->is_continuation_enter_intrinsic()) {
407 // This method only calls Continuation.enter()
408 Symbol* signature = vmSymbols::continuationEnter_signature();
409 fr.oops_compiled_arguments_do(signature, false, false, reg_map, f);
410 }
411 }
412
413 Method* CompiledMethod::attached_method(address call_instr) {
414 assert(code_contains(call_instr), "not part of the nmethod");
415 RelocIterator iter(this, call_instr, call_instr + 1);
416 while (iter.next()) {
417 if (iter.addr() == call_instr) {
418 switch(iter.type()) {
419 case relocInfo::static_call_type: return iter.static_call_reloc()->method_value();
420 case relocInfo::opt_virtual_call_type: return iter.opt_virtual_call_reloc()->method_value();
421 case relocInfo::virtual_call_type: return iter.virtual_call_reloc()->method_value();
422 default: break;
423 }
424 }
425 }
426 return NULL; // not found
427 }
428
429 Method* CompiledMethod::attached_method_before_pc(address pc) {
430 if (NativeCall::is_call_before(pc)) {
431 NativeCall* ncall = nativeCall_before(pc);
432 return attached_method(ncall->instruction_address());
433 }
434 return NULL; // not a call
435 }
436
437 void CompiledMethod::clear_inline_caches() {
438 assert(SafepointSynchronize::is_at_safepoint(), "clearing of IC's only allowed at safepoint");
439 RelocIterator iter(this);
440 while (iter.next()) {
441 iter.reloc()->clear_inline_cache();
442 }
443 }
444
445 // Clear IC callsites, releasing ICStubs of all compiled ICs
446 // as well as any associated CompiledICHolders.
447 void CompiledMethod::clear_ic_callsites() {
448 assert(CompiledICLocker::is_safe(this), "mt unsafe call");
449 ResourceMark rm;
450 RelocIterator iter(this);
451 while(iter.next()) {
452 if (iter.type() == relocInfo::virtual_call_type) {
453 CompiledIC* ic = CompiledIC_at(&iter);
454 ic->set_to_clean(false);
455 }
456 }
457 }
458
459 #ifdef ASSERT
460 // Check class_loader is alive for this bit of metadata.
461 class CheckClass : public MetadataClosure {
462 void do_metadata(Metadata* md) {
463 Klass* klass = NULL;
464 if (md->is_klass()) {
465 klass = ((Klass*)md);
466 } else if (md->is_method()) {
467 klass = ((Method*)md)->method_holder();
468 } else if (md->is_methodData()) {
469 klass = ((MethodData*)md)->method()->method_holder();
470 } else {
471 md->print();
472 ShouldNotReachHere();
473 }
474 assert(klass->is_loader_alive(), "must be alive");
475 }
476 };
477 #endif // ASSERT
478
479
480 bool CompiledMethod::clean_ic_if_metadata_is_dead(CompiledIC *ic) {
481 if (ic->is_clean()) {
482 return true;
483 }
484 if (ic->is_icholder_call()) {
485 // The only exception is compiledICHolder metadata which may
486 // yet be marked below. (We check this further below).
487 CompiledICHolder* cichk_metdata = ic->cached_icholder();
488
489 if (cichk_metdata->is_loader_alive()) {
490 return true;
491 }
492 } else {
493 Metadata* ic_metdata = ic->cached_metadata();
494 if (ic_metdata != NULL) {
495 if (ic_metdata->is_klass()) {
496 if (((Klass*)ic_metdata)->is_loader_alive()) {
497 return true;
498 }
499 } else if (ic_metdata->is_method()) {
500 Method* method = (Method*)ic_metdata;
501 assert(!method->is_old(), "old method should have been cleaned");
502 if (method->method_holder()->is_loader_alive()) {
503 return true;
504 }
505 } else {
506 ShouldNotReachHere();
507 }
508 } else {
509 // This inline cache is a megamorphic vtable call. Those ICs never hold
510 // any Metadata and should therefore never be cleaned by this function.
511 return true;
512 }
513 }
514
515 return ic->set_to_clean();
516 }
517
518 // Clean references to unloaded nmethods at addr from this one, which is not unloaded.
519 template <class CompiledICorStaticCall>
520 static bool clean_if_nmethod_is_unloaded(CompiledICorStaticCall *ic, address addr, CompiledMethod* from,
521 bool clean_all) {
522 CodeBlob *cb = CodeCache::find_blob(addr);
523 CompiledMethod* nm = (cb != NULL) ? cb->as_compiled_method_or_null() : NULL;
524 if (nm != NULL) {
525 // Clean inline caches pointing to bad nmethods
526 if (clean_all || !nm->is_in_use() || nm->is_unloading() || (nm->method()->code() != nm)) {
527 if (!ic->set_to_clean(!from->is_unloading())) {
528 return false;
529 }
530 assert(ic->is_clean(), "nmethod " PTR_FORMAT "not clean %s", p2i(from), from->method()->name_and_sig_as_C_string());
531 }
532 }
533 return true;
534 }
535
536 static bool clean_if_nmethod_is_unloaded(CompiledIC *ic, CompiledMethod* from,
537 bool clean_all) {
538 return clean_if_nmethod_is_unloaded(ic, ic->ic_destination(), from, clean_all);
539 }
540
541 static bool clean_if_nmethod_is_unloaded(CompiledStaticCall *csc, CompiledMethod* from,
542 bool clean_all) {
543 return clean_if_nmethod_is_unloaded(csc, csc->destination(), from, clean_all);
544 }
545
546 // Cleans caches in nmethods that point to either classes that are unloaded
547 // or nmethods that are unloaded.
548 //
549 // Can be called either in parallel by G1 currently or after all
550 // nmethods are unloaded. Return postponed=true in the parallel case for
551 // inline caches found that point to nmethods that are not yet visited during
552 // the do_unloading walk.
553 bool CompiledMethod::unload_nmethod_caches(bool unloading_occurred) {
554 ResourceMark rm;
555
556 // Exception cache only needs to be called if unloading occurred
557 if (unloading_occurred) {
558 clean_exception_cache();
559 }
560
561 if (!cleanup_inline_caches_impl(unloading_occurred, false)) {
562 return false;
563 }
564
565 #ifdef ASSERT
566 // Check that the metadata embedded in the nmethod is alive
567 CheckClass check_class;
568 metadata_do(&check_class);
569 #endif
570 return true;
571 }
572
573 void CompiledMethod::run_nmethod_entry_barrier() {
574 BarrierSetNMethod* bs_nm = BarrierSet::barrier_set()->barrier_set_nmethod();
575 if (bs_nm != NULL) {
576 // We want to keep an invariant that nmethods found through iterations of a Thread's
577 // nmethods found in safepoints have gone through an entry barrier and are not armed.
578 // By calling this nmethod entry barrier, it plays along and acts
579 // like any other nmethod found on the stack of a thread (fewer surprises).
580 nmethod* nm = as_nmethod_or_null();
581 if (nm != NULL && bs_nm->is_armed(nm)) {
582 bool alive = bs_nm->nmethod_entry_barrier(nm);
583 assert(alive, "should be alive");
584 }
585 }
586 }
587
588 // Only called by whitebox test
589 void CompiledMethod::cleanup_inline_caches_whitebox() {
590 assert_locked_or_safepoint(CodeCache_lock);
591 CompiledICLocker ic_locker(this);
592 guarantee(cleanup_inline_caches_impl(false /* unloading_occurred */, true /* clean_all */),
593 "Inline cache cleaning in a safepoint can't fail");
594 }
595
596 address* CompiledMethod::orig_pc_addr(const frame* fr) {
597 return (address*) ((address)fr->unextended_sp() + orig_pc_offset());
598 }
599
600 // Called to clean up after class unloading for live nmethods
601 bool CompiledMethod::cleanup_inline_caches_impl(bool unloading_occurred, bool clean_all) {
602 assert(CompiledICLocker::is_safe(this), "mt unsafe call");
603 ResourceMark rm;
604
605 // Find all calls in an nmethod and clear the ones that point to bad nmethods.
606 RelocIterator iter(this, oops_reloc_begin());
607 bool is_in_static_stub = false;
608 while(iter.next()) {
609
610 switch (iter.type()) {
611
612 case relocInfo::virtual_call_type:
613 if (unloading_occurred) {
614 // If class unloading occurred we first clear ICs where the cached metadata
615 // is referring to an unloaded klass or method.
616 if (!clean_ic_if_metadata_is_dead(CompiledIC_at(&iter))) {
617 return false;
618 }
619 }
620
621 if (!clean_if_nmethod_is_unloaded(CompiledIC_at(&iter), this, clean_all)) {
622 return false;
623 }
624 break;
625
626 case relocInfo::opt_virtual_call_type:
627 if (!clean_if_nmethod_is_unloaded(CompiledIC_at(&iter), this, clean_all)) {
628 return false;
629 }
630 break;
631
632 case relocInfo::static_call_type:
633 if (!clean_if_nmethod_is_unloaded(compiledStaticCall_at(iter.reloc()), this, clean_all)) {
634 return false;
635 }
636 break;
637
638 case relocInfo::static_stub_type: {
639 is_in_static_stub = true;
640 break;
641 }
642
643 case relocInfo::metadata_type: {
644 // Only the metadata relocations contained in static/opt virtual call stubs
645 // contains the Method* passed to c2i adapters. It is the only metadata
646 // relocation that needs to be walked, as it is the one metadata relocation
647 // that violates the invariant that all metadata relocations have an oop
648 // in the compiled method (due to deferred resolution and code patching).
649
650 // This causes dead metadata to remain in compiled methods that are not
651 // unloading. Unless these slippery metadata relocations of the static
652 // stubs are at least cleared, subsequent class redefinition operations
653 // will access potentially free memory, and JavaThread execution
654 // concurrent to class unloading may call c2i adapters with dead methods.
655 if (!is_in_static_stub) {
656 // The first metadata relocation after a static stub relocation is the
657 // metadata relocation of the static stub used to pass the Method* to
658 // c2i adapters.
659 continue;
660 }
661 is_in_static_stub = false;
662 if (is_unloading()) {
663 // If the nmethod itself is dying, then it may point at dead metadata.
664 // Nobody should follow that metadata; it is strictly unsafe.
665 continue;
666 }
667 metadata_Relocation* r = iter.metadata_reloc();
668 Metadata* md = r->metadata_value();
669 if (md != NULL && md->is_method()) {
670 Method* method = static_cast<Method*>(md);
671 if (!method->method_holder()->is_loader_alive()) {
672 Atomic::store(r->metadata_addr(), (Method*)NULL);
673
674 if (!r->metadata_is_immediate()) {
675 r->fix_metadata_relocation();
676 }
677 }
678 }
679 break;
680 }
681
682 default:
683 break;
684 }
685 }
686
687 return true;
688 }
689
690 address CompiledMethod::continuation_for_implicit_exception(address pc, bool for_div0_check) {
691 // Exception happened outside inline-cache check code => we are inside
692 // an active nmethod => use cpc to determine a return address
693 int exception_offset = pc - code_begin();
694 int cont_offset = ImplicitExceptionTable(this).continuation_offset( exception_offset );
695 #ifdef ASSERT
696 if (cont_offset == 0) {
697 Thread* thread = Thread::current();
698 ResourceMark rm(thread);
699 CodeBlob* cb = CodeCache::find_blob(pc);
700 assert(cb != NULL && cb == this, "");
701 ttyLocker ttyl;
702 tty->print_cr("implicit exception happened at " INTPTR_FORMAT, p2i(pc));
703 print();
704 method()->print_codes();
705 print_code();
706 print_pcs();
707 }
708 #endif
709 if (cont_offset == 0) {
710 // Let the normal error handling report the exception
711 return NULL;
712 }
713 if (cont_offset == exception_offset) {
714 #if INCLUDE_JVMCI
715 Deoptimization::DeoptReason deopt_reason = for_div0_check ? Deoptimization::Reason_div0_check : Deoptimization::Reason_null_check;
716 JavaThread *thread = JavaThread::current();
717 thread->set_jvmci_implicit_exception_pc(pc);
718 thread->set_pending_deoptimization(Deoptimization::make_trap_request(deopt_reason,
719 Deoptimization::Action_reinterpret));
720 return (SharedRuntime::deopt_blob()->implicit_exception_uncommon_trap());
721 #else
722 ShouldNotReachHere();
723 #endif
724 }
725 return code_begin() + cont_offset;
726 }
727
728 class HasEvolDependency : public MetadataClosure {
729 bool _has_evol_dependency;
730 public:
731 HasEvolDependency() : _has_evol_dependency(false) {}
732 void do_metadata(Metadata* md) {
733 if (md->is_method()) {
734 Method* method = (Method*)md;
735 if (method->is_old()) {
736 _has_evol_dependency = true;
737 }
738 }
739 }
740 bool has_evol_dependency() const { return _has_evol_dependency; }
741 };
742
743 bool CompiledMethod::has_evol_metadata() {
744 // Check the metadata in relocIter and CompiledIC and also deoptimize
745 // any nmethod that has reference to old methods.
746 HasEvolDependency check_evol;
747 metadata_do(&check_evol);
748 if (check_evol.has_evol_dependency() && log_is_enabled(Debug, redefine, class, nmethod)) {
749 ResourceMark rm;
750 log_debug(redefine, class, nmethod)
751 ("Found evol dependency of nmethod %s.%s(%s) compile_id=%d on in nmethod metadata",
752 _method->method_holder()->external_name(),
753 _method->name()->as_C_string(),
754 _method->signature()->as_C_string(),
755 compile_id());
756 }
757 return check_evol.has_evol_dependency();
758 }