1 /*
2 * Copyright (c) 2015, 2017, 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/scopeDesc.hpp"
29 #include "code/codeCache.hpp"
30 #include "prims/methodHandles.hpp"
31 #include "interpreter/bytecode.hpp"
32 #include "memory/resourceArea.hpp"
33 #include "runtime/mutexLocker.hpp"
34
35 CompiledMethod::CompiledMethod(Method* method, const char* name, CompilerType type, const CodeBlobLayout& layout, int frame_complete_offset, int frame_size, ImmutableOopMapSet* oop_maps, bool caller_must_gc_arguments)
36 : CodeBlob(name, type, layout, frame_complete_offset, frame_size, oop_maps, caller_must_gc_arguments),
37 _method(method), _mark_for_deoptimization_status(not_marked) {
38 init_defaults();
39 }
40
41 CompiledMethod::CompiledMethod(Method* method, const char* name, CompilerType type, int size, int header_size, CodeBuffer* cb, int frame_complete_offset, int frame_size, OopMapSet* oop_maps, bool caller_must_gc_arguments)
42 : CodeBlob(name, type, CodeBlobLayout((address) this, size, header_size, cb), cb, frame_complete_offset, frame_size, oop_maps, caller_must_gc_arguments),
43 _method(method), _mark_for_deoptimization_status(not_marked) {
44 init_defaults();
45 }
46
47 void CompiledMethod::init_defaults() {
48 _has_unsafe_access = 0;
49 _has_method_handle_invokes = 0;
50 _lazy_critical_native = 0;
51 _has_wide_vectors = 0;
52 _unloading_clock = 0;
53 }
54
55 bool CompiledMethod::is_method_handle_return(address return_pc) {
56 if (!has_method_handle_invokes()) return false;
57 PcDesc* pd = pc_desc_at(return_pc);
58 if (pd == NULL)
59 return false;
60 return pd->is_method_handle_invoke();
61 }
62
63 // Returns a string version of the method state.
64 const char* CompiledMethod::state() const {
65 int state = get_state();
66 switch (state) {
67 case in_use:
68 return "in use";
69 case not_used:
70 return "not_used";
71 case not_entrant:
72 return "not_entrant";
73 case zombie:
74 return "zombie";
75 case unloaded:
76 return "unloaded";
77 default:
78 fatal("unexpected method state: %d", state);
79 return NULL;
80 }
81 }
82
83 //-----------------------------------------------------------------------------
84
85 void CompiledMethod::add_exception_cache_entry(ExceptionCache* new_entry) {
86 assert(ExceptionCache_lock->owned_by_self(),"Must hold the ExceptionCache_lock");
87 assert(new_entry != NULL,"Must be non null");
88 assert(new_entry->next() == NULL, "Must be null");
89
90 ExceptionCache *ec = exception_cache();
91 if (ec != NULL) {
92 new_entry->set_next(ec);
93 }
94 release_set_exception_cache(new_entry);
95 }
96
97 void CompiledMethod::clean_exception_cache(BoolObjectClosure* is_alive) {
98 ExceptionCache* prev = NULL;
99 ExceptionCache* curr = exception_cache();
100
101 while (curr != NULL) {
102 ExceptionCache* next = curr->next();
103
104 Klass* ex_klass = curr->exception_type();
105 if (ex_klass != NULL && !ex_klass->is_loader_alive(is_alive)) {
106 if (prev == NULL) {
107 set_exception_cache(next);
108 } else {
109 prev->set_next(next);
110 }
111 delete curr;
112 // prev stays the same.
113 } else {
114 prev = curr;
115 }
116
117 curr = next;
118 }
119 }
120
121 // public method for accessing the exception cache
122 // These are the public access methods.
123 address CompiledMethod::handler_for_exception_and_pc(Handle exception, address pc) {
124 // We never grab a lock to read the exception cache, so we may
125 // have false negatives. This is okay, as it can only happen during
126 // the first few exception lookups for a given nmethod.
127 ExceptionCache* ec = exception_cache();
128 while (ec != NULL) {
129 address ret_val;
130 if ((ret_val = ec->match(exception,pc)) != NULL) {
131 return ret_val;
132 }
133 ec = ec->next();
134 }
135 return NULL;
136 }
137
138 void CompiledMethod::add_handler_for_exception_and_pc(Handle exception, address pc, address handler) {
139 // There are potential race conditions during exception cache updates, so we
140 // must own the ExceptionCache_lock before doing ANY modifications. Because
141 // we don't lock during reads, it is possible to have several threads attempt
142 // to update the cache with the same data. We need to check for already inserted
143 // copies of the current data before adding it.
144
145 MutexLocker ml(ExceptionCache_lock);
146 ExceptionCache* target_entry = exception_cache_entry_for_exception(exception);
147
148 if (target_entry == NULL || !target_entry->add_address_and_handler(pc,handler)) {
149 target_entry = new ExceptionCache(exception,pc,handler);
150 add_exception_cache_entry(target_entry);
151 }
152 }
153
154 //-------------end of code for ExceptionCache--------------
155
156 // private method for handling exception cache
157 // These methods are private, and used to manipulate the exception cache
158 // directly.
159 ExceptionCache* CompiledMethod::exception_cache_entry_for_exception(Handle exception) {
160 ExceptionCache* ec = exception_cache();
161 while (ec != NULL) {
162 if (ec->match_exception_with_space(exception)) {
163 return ec;
164 }
165 ec = ec->next();
166 }
167 return NULL;
168 }
169
170 bool CompiledMethod::is_at_poll_return(address pc) {
171 RelocIterator iter(this, pc, pc+1);
172 while (iter.next()) {
173 if (iter.type() == relocInfo::poll_return_type)
174 return true;
175 }
176 return false;
177 }
178
179
180 bool CompiledMethod::is_at_poll_or_poll_return(address pc) {
181 RelocIterator iter(this, pc, pc+1);
182 while (iter.next()) {
183 relocInfo::relocType t = iter.type();
184 if (t == relocInfo::poll_return_type || t == relocInfo::poll_type)
185 return true;
186 }
187 return false;
188 }
189
190 void CompiledMethod::verify_oop_relocations() {
191 // Ensure sure that the code matches the current oop values
192 RelocIterator iter(this, NULL, NULL);
193 while (iter.next()) {
194 if (iter.type() == relocInfo::oop_type) {
195 oop_Relocation* reloc = iter.oop_reloc();
196 if (!reloc->oop_is_immediate()) {
197 reloc->verify_oop_relocation();
198 }
199 }
200 }
201 }
202
203
204 ScopeDesc* CompiledMethod::scope_desc_at(address pc) {
205 PcDesc* pd = pc_desc_at(pc);
206 guarantee(pd != NULL, "scope must be present");
207 return new ScopeDesc(this, pd->scope_decode_offset(),
208 pd->obj_decode_offset(), pd->should_reexecute(), pd->rethrow_exception(),
209 pd->return_oop());
210 }
211
212 ScopeDesc* CompiledMethod::scope_desc_near(address pc) {
213 PcDesc* pd = pc_desc_near(pc);
214 guarantee(pd != NULL, "scope must be present");
215 return new ScopeDesc(this, pd->scope_decode_offset(),
216 pd->obj_decode_offset(), pd->should_reexecute(), pd->rethrow_exception(),
217 pd->return_oop());
218 }
219
220 void CompiledMethod::cleanup_inline_caches(bool clean_all/*=false*/) {
221 assert_locked_or_safepoint(CompiledIC_lock);
222
223 // If the method is not entrant or zombie then a JMP is plastered over the
224 // first few bytes. If an oop in the old code was there, that oop
225 // should not get GC'd. Skip the first few bytes of oops on
226 // not-entrant methods.
227 address low_boundary = verified_entry_point();
228 if (!is_in_use() && is_nmethod()) {
229 low_boundary += NativeJump::instruction_size;
230 // %%% Note: On SPARC we patch only a 4-byte trap, not a full NativeJump.
231 // This means that the low_boundary is going to be a little too high.
232 // This shouldn't matter, since oops of non-entrant methods are never used.
233 // In fact, why are we bothering to look at oops in a non-entrant method??
234 }
235
236 // Find all calls in an nmethod and clear the ones that point to non-entrant,
237 // zombie and unloaded nmethods.
238 ResourceMark rm;
239 RelocIterator iter(this, low_boundary);
240 while(iter.next()) {
241 switch(iter.type()) {
242 case relocInfo::virtual_call_type:
243 case relocInfo::opt_virtual_call_type: {
244 CompiledIC *ic = CompiledIC_at(&iter);
245 // Ok, to lookup references to zombies here
246 CodeBlob *cb = CodeCache::find_blob_unsafe(ic->ic_destination());
247 if( cb != NULL && cb->is_compiled() ) {
248 CompiledMethod* nm = cb->as_compiled_method();
249 // Clean inline caches pointing to zombie, non-entrant and unloaded methods
250 if (clean_all || !nm->is_in_use() || (nm->method()->code() != nm)) ic->set_to_clean(is_alive());
251 }
252 break;
253 }
254 case relocInfo::static_call_type: {
255 CompiledStaticCall *csc = compiledStaticCall_at(iter.reloc());
256 CodeBlob *cb = CodeCache::find_blob_unsafe(csc->destination());
257 if( cb != NULL && cb->is_compiled() ) {
258 CompiledMethod* cm = cb->as_compiled_method();
259 // Clean inline caches pointing to zombie, non-entrant and unloaded methods
260 if (clean_all || !cm->is_in_use() || (cm->method()->code() != cm)) {
261 csc->set_to_clean();
262 }
263 }
264 break;
265 }
266 default:
267 break;
268 }
269 }
270 }
271
272 int CompiledMethod::verify_icholder_relocations() {
273 ResourceMark rm;
274 int count = 0;
275
276 RelocIterator iter(this);
277 while(iter.next()) {
278 if (iter.type() == relocInfo::virtual_call_type) {
279 if (CompiledIC::is_icholder_call_site(iter.virtual_call_reloc(), this)) {
280 CompiledIC *ic = CompiledIC_at(&iter);
281 if (TraceCompiledIC) {
282 tty->print("noticed icholder " INTPTR_FORMAT " ", p2i(ic->cached_icholder()));
283 ic->print();
284 }
285 assert(ic->cached_icholder() != NULL, "must be non-NULL");
286 count++;
287 }
288 }
289 }
290
291 return count;
292 }
293
294 // Method that knows how to preserve outgoing arguments at call. This method must be
295 // called with a frame corresponding to a Java invoke
296 void CompiledMethod::preserve_callee_argument_oops(frame fr, const RegisterMap *reg_map, OopClosure* f) {
297 if (method() != NULL && !method()->is_native()) {
298 address pc = fr.pc();
299 SimpleScopeDesc ssd(this, pc);
300 Bytecode_invoke call(ssd.method(), ssd.bci());
301 bool has_receiver = call.has_receiver();
302 bool has_appendix = call.has_appendix();
303 Symbol* signature = call.signature();
304
305 // The method attached by JIT-compilers should be used, if present.
306 // Bytecode can be inaccurate in such case.
307 Method* callee = attached_method_before_pc(pc);
308 if (callee != NULL) {
309 has_receiver = !(callee->access_flags().is_static());
310 has_appendix = false;
311 signature = callee->signature();
312 }
313
314 fr.oops_compiled_arguments_do(signature, has_receiver, has_appendix, reg_map, f);
315 }
316 }
317
318 Method* CompiledMethod::attached_method(address call_instr) {
319 assert(code_contains(call_instr), "not part of the nmethod");
320 RelocIterator iter(this, call_instr, call_instr + 1);
321 while (iter.next()) {
322 if (iter.addr() == call_instr) {
323 switch(iter.type()) {
324 case relocInfo::static_call_type: return iter.static_call_reloc()->method_value();
325 case relocInfo::opt_virtual_call_type: return iter.opt_virtual_call_reloc()->method_value();
326 case relocInfo::virtual_call_type: return iter.virtual_call_reloc()->method_value();
327 default: break;
328 }
329 }
330 }
331 return NULL; // not found
332 }
333
334 Method* CompiledMethod::attached_method_before_pc(address pc) {
335 if (NativeCall::is_call_before(pc)) {
336 NativeCall* ncall = nativeCall_before(pc);
337 return attached_method(ncall->instruction_address());
338 }
339 return NULL; // not a call
340 }
341
342 void CompiledMethod::clear_inline_caches() {
343 assert(SafepointSynchronize::is_at_safepoint(), "cleaning of IC's only allowed at safepoint");
344 if (is_zombie()) {
345 return;
346 }
347
348 RelocIterator iter(this);
349 while (iter.next()) {
350 iter.reloc()->clear_inline_cache();
351 }
352 }
353
354 // Clear ICStubs of all compiled ICs
355 void CompiledMethod::clear_ic_stubs() {
356 assert_locked_or_safepoint(CompiledIC_lock);
357 RelocIterator iter(this);
358 while(iter.next()) {
359 if (iter.type() == relocInfo::virtual_call_type) {
360 CompiledIC* ic = CompiledIC_at(&iter);
361 ic->clear_ic_stub();
362 }
363 }
364 }
365
366 #ifdef ASSERT
367
368 class CheckClass : AllStatic {
369 static BoolObjectClosure* _is_alive;
370
371 // Check class_loader is alive for this bit of metadata.
372 static void check_class(Metadata* md) {
373 Klass* klass = NULL;
374 if (md->is_klass()) {
375 klass = ((Klass*)md);
376 } else if (md->is_method()) {
377 klass = ((Method*)md)->method_holder();
378 } else if (md->is_methodData()) {
379 klass = ((MethodData*)md)->method()->method_holder();
380 } else {
381 md->print();
382 ShouldNotReachHere();
383 }
384 assert(klass->is_loader_alive(_is_alive), "must be alive");
385 }
386 public:
387 static void do_check_class(BoolObjectClosure* is_alive, CompiledMethod* nm) {
388 assert(SafepointSynchronize::is_at_safepoint(), "this is only ok at safepoint");
389 _is_alive = is_alive;
390 nm->metadata_do(check_class);
391 }
392 };
393
394 // This is called during a safepoint so can use static data
395 BoolObjectClosure* CheckClass::_is_alive = NULL;
396 #endif // ASSERT
397
398
399 void CompiledMethod::clean_ic_if_metadata_is_dead(CompiledIC *ic, BoolObjectClosure *is_alive) {
400 if (ic->is_icholder_call()) {
401 // The only exception is compiledICHolder oops which may
402 // yet be marked below. (We check this further below).
403 CompiledICHolder* cichk_oop = ic->cached_icholder();
404
405 if (cichk_oop->holder_method()->method_holder()->is_loader_alive(is_alive) &&
406 cichk_oop->holder_klass()->is_loader_alive(is_alive)) {
407 return;
408 }
409 } else {
410 Metadata* ic_oop = ic->cached_metadata();
411 if (ic_oop != NULL) {
412 if (ic_oop->is_klass()) {
413 if (((Klass*)ic_oop)->is_loader_alive(is_alive)) {
414 return;
415 }
416 } else if (ic_oop->is_method()) {
417 if (((Method*)ic_oop)->method_holder()->is_loader_alive(is_alive)) {
418 return;
419 }
420 } else {
421 ShouldNotReachHere();
422 }
423 }
424 }
425
426 ic->set_to_clean();
427 }
428
429 unsigned char CompiledMethod::_global_unloading_clock = 0;
430
431 void CompiledMethod::increase_unloading_clock() {
432 _global_unloading_clock++;
433 if (_global_unloading_clock == 0) {
434 // _nmethods are allocated with _unloading_clock == 0,
435 // so 0 is never used as a clock value.
436 _global_unloading_clock = 1;
437 }
438 }
439
440 void CompiledMethod::set_unloading_clock(unsigned char unloading_clock) {
441 OrderAccess::release_store((volatile jubyte*)&_unloading_clock, unloading_clock);
442 }
443
444 unsigned char CompiledMethod::unloading_clock() {
445 return (unsigned char)OrderAccess::load_acquire((volatile jubyte*)&_unloading_clock);
446 }
447
448 // Processing of oop references should have been sufficient to keep
449 // all strong references alive. Any weak references should have been
450 // cleared as well. Visit all the metadata and ensure that it's
451 // really alive.
452 void CompiledMethod::verify_metadata_loaders(address low_boundary, BoolObjectClosure* is_alive) {
453 #ifdef ASSERT
454 RelocIterator iter(this, low_boundary);
455 while (iter.next()) {
456 // static_stub_Relocations may have dangling references to
457 // Method*s so trim them out here. Otherwise it looks like
458 // compiled code is maintaining a link to dead metadata.
459 address static_call_addr = NULL;
460 if (iter.type() == relocInfo::opt_virtual_call_type) {
461 CompiledIC* cic = CompiledIC_at(&iter);
462 if (!cic->is_call_to_interpreted()) {
463 static_call_addr = iter.addr();
464 }
465 } else if (iter.type() == relocInfo::static_call_type) {
466 CompiledStaticCall* csc = compiledStaticCall_at(iter.reloc());
467 if (!csc->is_call_to_interpreted()) {
468 static_call_addr = iter.addr();
469 }
470 }
471 if (static_call_addr != NULL) {
472 RelocIterator sciter(this, low_boundary);
473 while (sciter.next()) {
474 if (sciter.type() == relocInfo::static_stub_type &&
475 sciter.static_stub_reloc()->static_call() == static_call_addr) {
476 sciter.static_stub_reloc()->clear_inline_cache();
477 }
478 }
479 }
480 }
481 // Check that the metadata embedded in the nmethod is alive
482 CheckClass::do_check_class(is_alive, this);
483 #endif
484 }
485
486 // This is called at the end of the strong tracing/marking phase of a
487 // GC to unload an nmethod if it contains otherwise unreachable
488 // oops.
489
490 void CompiledMethod::do_unloading(BoolObjectClosure* is_alive, bool unloading_occurred) {
491 // Make sure the oop's ready to receive visitors
492 assert(!is_zombie() && !is_unloaded(),
493 "should not call follow on zombie or unloaded nmethod");
494
495 // If the method is not entrant then a JMP is plastered over the
496 // first few bytes. If an oop in the old code was there, that oop
497 // should not get GC'd. Skip the first few bytes of oops on
498 // not-entrant methods.
499 address low_boundary = verified_entry_point();
500 if (is_not_entrant()) {
501 low_boundary += NativeJump::instruction_size;
502 // %%% Note: On SPARC we patch only a 4-byte trap, not a full NativeJump.
503 // (See comment above.)
504 }
505
506 // The RedefineClasses() API can cause the class unloading invariant
507 // to no longer be true. See jvmtiExport.hpp for details.
508 // Also, leave a debugging breadcrumb in local flag.
509 if (JvmtiExport::has_redefined_a_class()) {
510 // This set of the unloading_occurred flag is done before the
511 // call to post_compiled_method_unload() so that the unloading
512 // of this nmethod is reported.
513 unloading_occurred = true;
514 }
515
516 // Exception cache
517 clean_exception_cache(is_alive);
518
519 // If class unloading occurred we first iterate over all inline caches and
520 // clear ICs where the cached oop is referring to an unloaded klass or method.
521 // The remaining live cached oops will be traversed in the relocInfo::oop_type
522 // iteration below.
523 if (unloading_occurred) {
524 RelocIterator iter(this, low_boundary);
525 while(iter.next()) {
526 if (iter.type() == relocInfo::virtual_call_type) {
527 CompiledIC *ic = CompiledIC_at(&iter);
528 clean_ic_if_metadata_is_dead(ic, is_alive);
529 }
530 }
531 }
532
533 if (do_unloading_oops(low_boundary, is_alive, unloading_occurred)) {
534 return;
535 }
536
537 #if INCLUDE_JVMCI
538 if (do_unloading_jvmci(is_alive, unloading_occurred)) {
539 return;
540 }
541 #endif
542
543 // Ensure that all metadata is still alive
544 verify_metadata_loaders(low_boundary, is_alive);
545 }
546
547 template <class CompiledICorStaticCall>
548 static bool clean_if_nmethod_is_unloaded(CompiledICorStaticCall *ic, address addr, BoolObjectClosure *is_alive, CompiledMethod* from) {
549 // Ok, to lookup references to zombies here
550 CodeBlob *cb = CodeCache::find_blob_unsafe(addr);
551 CompiledMethod* nm = (cb != NULL) ? cb->as_compiled_method_or_null() : NULL;
552 if (nm != NULL) {
553 if (nm->unloading_clock() != CompiledMethod::global_unloading_clock()) {
554 // The nmethod has not been processed yet.
555 return true;
556 }
557
558 // Clean inline caches pointing to both zombie and not_entrant methods
559 if (!nm->is_in_use() || (nm->method()->code() != nm)) {
560 ic->set_to_clean();
561 assert(ic->is_clean(), "nmethod " PTR_FORMAT "not clean %s", p2i(from), from->method()->name_and_sig_as_C_string());
562 }
563 }
564
565 return false;
566 }
567
568 static bool clean_if_nmethod_is_unloaded(CompiledIC *ic, BoolObjectClosure *is_alive, CompiledMethod* from) {
569 return clean_if_nmethod_is_unloaded(ic, ic->ic_destination(), is_alive, from);
570 }
571
572 static bool clean_if_nmethod_is_unloaded(CompiledStaticCall *csc, BoolObjectClosure *is_alive, CompiledMethod* from) {
573 return clean_if_nmethod_is_unloaded(csc, csc->destination(), is_alive, from);
574 }
575
576 bool CompiledMethod::do_unloading_parallel(BoolObjectClosure* is_alive, bool unloading_occurred) {
577 ResourceMark rm;
578
579 // Make sure the oop's ready to receive visitors
580 assert(!is_zombie() && !is_unloaded(),
581 "should not call follow on zombie or unloaded nmethod");
582
583 // If the method is not entrant then a JMP is plastered over the
584 // first few bytes. If an oop in the old code was there, that oop
585 // should not get GC'd. Skip the first few bytes of oops on
586 // not-entrant methods.
587 address low_boundary = verified_entry_point();
588 if (is_not_entrant()) {
589 low_boundary += NativeJump::instruction_size;
590 // %%% Note: On SPARC we patch only a 4-byte trap, not a full NativeJump.
591 // (See comment above.)
592 }
593
594 // The RedefineClasses() API can cause the class unloading invariant
595 // to no longer be true. See jvmtiExport.hpp for details.
596 // Also, leave a debugging breadcrumb in local flag.
597 if (JvmtiExport::has_redefined_a_class()) {
598 // This set of the unloading_occurred flag is done before the
599 // call to post_compiled_method_unload() so that the unloading
600 // of this nmethod is reported.
601 unloading_occurred = true;
602 }
603
604 // Exception cache
605 clean_exception_cache(is_alive);
606
607 bool postponed = false;
608
609 RelocIterator iter(this, low_boundary);
610 while(iter.next()) {
611
612 switch (iter.type()) {
613
614 case relocInfo::virtual_call_type:
615 if (unloading_occurred) {
616 // If class unloading occurred we first iterate over all inline caches and
617 // clear ICs where the cached oop is referring to an unloaded klass or method.
618 clean_ic_if_metadata_is_dead(CompiledIC_at(&iter), is_alive);
619 }
620
621 postponed |= clean_if_nmethod_is_unloaded(CompiledIC_at(&iter), is_alive, this);
622 break;
623
624 case relocInfo::opt_virtual_call_type:
625 postponed |= clean_if_nmethod_is_unloaded(CompiledIC_at(&iter), is_alive, this);
626 break;
627
628 case relocInfo::static_call_type:
629 postponed |= clean_if_nmethod_is_unloaded(compiledStaticCall_at(iter.reloc()), is_alive, this);
630 break;
631
632 case relocInfo::oop_type:
633 // handled by do_unloading_oops below
634 break;
635
636 case relocInfo::metadata_type:
637 break; // nothing to do.
638
639 default:
640 break;
641 }
642 }
643
644 if (do_unloading_oops(low_boundary, is_alive, unloading_occurred)) {
645 return postponed;
646 }
647
648 #if INCLUDE_JVMCI
649 if (do_unloading_jvmci(is_alive, unloading_occurred)) {
650 return postponed;
651 }
652 #endif
653
654 // Ensure that all metadata is still alive
655 verify_metadata_loaders(low_boundary, is_alive);
656
657 return postponed;
658 }
659
660 void CompiledMethod::do_unloading_parallel_postponed(BoolObjectClosure* is_alive, bool unloading_occurred) {
661 ResourceMark rm;
662
663 // Make sure the oop's ready to receive visitors
664 assert(!is_zombie(),
665 "should not call follow on zombie nmethod");
666
667 // If the method is not entrant then a JMP is plastered over the
668 // first few bytes. If an oop in the old code was there, that oop
669 // should not get GC'd. Skip the first few bytes of oops on
670 // not-entrant methods.
671 address low_boundary = verified_entry_point();
672 if (is_not_entrant()) {
673 low_boundary += NativeJump::instruction_size;
674 // %%% Note: On SPARC we patch only a 4-byte trap, not a full NativeJump.
675 // (See comment above.)
676 }
677
678 RelocIterator iter(this, low_boundary);
679 while(iter.next()) {
680
681 switch (iter.type()) {
682
683 case relocInfo::virtual_call_type:
684 clean_if_nmethod_is_unloaded(CompiledIC_at(&iter), is_alive, this);
685 break;
686
687 case relocInfo::opt_virtual_call_type:
688 clean_if_nmethod_is_unloaded(CompiledIC_at(&iter), is_alive, this);
689 break;
690
691 case relocInfo::static_call_type:
692 clean_if_nmethod_is_unloaded(compiledStaticCall_at(iter.reloc()), is_alive, this);
693 break;
694
695 default:
696 break;
697 }
698 }
699 }