1 /*
2 * Copyright (c) 2015, 2018, 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 "interpreter/bytecode.inline.hpp"
31 #include "logging/log.hpp"
32 #include "logging/logTag.hpp"
33 #include "memory/resourceArea.hpp"
34 #include "oops/methodData.hpp"
35 #include "oops/method.inline.hpp"
36 #include "prims/methodHandles.hpp"
37 #include "runtime/handles.inline.hpp"
38 #include "runtime/mutexLocker.hpp"
39
40 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)
41 : CodeBlob(name, type, layout, frame_complete_offset, frame_size, oop_maps, caller_must_gc_arguments),
42 _mark_for_deoptimization_status(not_marked), _method(method) {
43 init_defaults();
44 }
45
46 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)
47 : CodeBlob(name, type, CodeBlobLayout((address) this, size, header_size, cb), cb, frame_complete_offset, frame_size, oop_maps, caller_must_gc_arguments),
48 _mark_for_deoptimization_status(not_marked), _method(method) {
49 init_defaults();
50 }
51
52 void CompiledMethod::init_defaults() {
53 _has_unsafe_access = 0;
54 _has_method_handle_invokes = 0;
55 _lazy_critical_native = 0;
56 _has_wide_vectors = 0;
57 _unloading_clock = 0;
58 }
59
60 bool CompiledMethod::is_method_handle_return(address return_pc) {
61 if (!has_method_handle_invokes()) return false;
62 PcDesc* pd = pc_desc_at(return_pc);
63 if (pd == NULL)
64 return false;
65 return pd->is_method_handle_invoke();
66 }
67
68 // Returns a string version of the method state.
69 const char* CompiledMethod::state() const {
70 int state = get_state();
71 switch (state) {
72 case not_installed:
73 return "not installed";
74 case in_use:
75 return "in use";
76 case not_used:
77 return "not_used";
78 case not_entrant:
79 return "not_entrant";
80 case zombie:
81 return "zombie";
82 case unloaded:
83 return "unloaded";
84 default:
85 fatal("unexpected method state: %d", state);
86 return NULL;
87 }
88 }
89
90 //-----------------------------------------------------------------------------
91
92 void CompiledMethod::add_exception_cache_entry(ExceptionCache* new_entry) {
93 assert(ExceptionCache_lock->owned_by_self(),"Must hold the ExceptionCache_lock");
94 assert(new_entry != NULL,"Must be non null");
95 assert(new_entry->next() == NULL, "Must be null");
96
97 ExceptionCache *ec = exception_cache();
98 if (ec != NULL) {
99 new_entry->set_next(ec);
100 }
101 release_set_exception_cache(new_entry);
102 }
103
104 void CompiledMethod::clean_exception_cache() {
105 ExceptionCache* prev = NULL;
106 ExceptionCache* curr = exception_cache();
107
108 while (curr != NULL) {
109 ExceptionCache* next = curr->next();
110
111 Klass* ex_klass = curr->exception_type();
112 if (ex_klass != NULL && !ex_klass->is_loader_alive()) {
113 if (prev == NULL) {
114 set_exception_cache(next);
115 } else {
116 prev->set_next(next);
117 }
118 delete curr;
119 // prev stays the same.
120 } else {
121 prev = curr;
122 }
123
124 curr = next;
125 }
126 }
127
128 // public method for accessing the exception cache
129 // These are the public access methods.
130 address CompiledMethod::handler_for_exception_and_pc(Handle exception, address pc) {
131 // We never grab a lock to read the exception cache, so we may
132 // have false negatives. This is okay, as it can only happen during
133 // the first few exception lookups for a given nmethod.
134 ExceptionCache* ec = exception_cache();
135 while (ec != NULL) {
136 address ret_val;
137 if ((ret_val = ec->match(exception,pc)) != NULL) {
138 return ret_val;
139 }
140 ec = ec->next();
141 }
142 return NULL;
143 }
144
145 void CompiledMethod::add_handler_for_exception_and_pc(Handle exception, address pc, address handler) {
146 // There are potential race conditions during exception cache updates, so we
147 // must own the ExceptionCache_lock before doing ANY modifications. Because
148 // we don't lock during reads, it is possible to have several threads attempt
149 // to update the cache with the same data. We need to check for already inserted
150 // copies of the current data before adding it.
151
152 MutexLocker ml(ExceptionCache_lock);
153 ExceptionCache* target_entry = exception_cache_entry_for_exception(exception);
154
155 if (target_entry == NULL || !target_entry->add_address_and_handler(pc,handler)) {
156 target_entry = new ExceptionCache(exception,pc,handler);
157 add_exception_cache_entry(target_entry);
158 }
159 }
160
161 //-------------end of code for ExceptionCache--------------
162
163 // private method for handling exception cache
164 // These methods are private, and used to manipulate the exception cache
165 // directly.
166 ExceptionCache* CompiledMethod::exception_cache_entry_for_exception(Handle exception) {
167 ExceptionCache* ec = exception_cache();
168 while (ec != NULL) {
169 if (ec->match_exception_with_space(exception)) {
170 return ec;
171 }
172 ec = ec->next();
173 }
174 return NULL;
175 }
176
177 bool CompiledMethod::is_at_poll_return(address pc) {
178 RelocIterator iter(this, pc, pc+1);
179 while (iter.next()) {
180 if (iter.type() == relocInfo::poll_return_type)
181 return true;
182 }
183 return false;
184 }
185
186
187 bool CompiledMethod::is_at_poll_or_poll_return(address pc) {
188 RelocIterator iter(this, pc, pc+1);
189 while (iter.next()) {
190 relocInfo::relocType t = iter.type();
191 if (t == relocInfo::poll_return_type || t == relocInfo::poll_type)
192 return true;
193 }
194 return false;
195 }
196
197 void CompiledMethod::verify_oop_relocations() {
198 // Ensure sure that the code matches the current oop values
199 RelocIterator iter(this, NULL, NULL);
200 while (iter.next()) {
201 if (iter.type() == relocInfo::oop_type) {
202 oop_Relocation* reloc = iter.oop_reloc();
203 if (!reloc->oop_is_immediate()) {
204 reloc->verify_oop_relocation();
205 }
206 }
207 }
208 }
209
210
211 ScopeDesc* CompiledMethod::scope_desc_at(address pc) {
212 PcDesc* pd = pc_desc_at(pc);
213 guarantee(pd != NULL, "scope must be present");
214 return new ScopeDesc(this, pd->scope_decode_offset(),
215 pd->obj_decode_offset(), pd->should_reexecute(), pd->rethrow_exception(),
216 pd->return_oop());
217 }
218
219 ScopeDesc* CompiledMethod::scope_desc_near(address pc) {
220 PcDesc* pd = pc_desc_near(pc);
221 guarantee(pd != NULL, "scope must be present");
222 return new ScopeDesc(this, pd->scope_decode_offset(),
223 pd->obj_decode_offset(), pd->should_reexecute(), pd->rethrow_exception(),
224 pd->return_oop());
225 }
226
227 address CompiledMethod::oops_reloc_begin() const {
228 // If the method is not entrant or zombie then a JMP is plastered over the
229 // first few bytes. Therefore, we do not allow an oop in the first
230 // NativeJump::instruction_size after the verified entry. Since the
231 // frame is being built in this path, that guarantees such oops can not
232 // exist until the frame is completed, which should be strictly later.
233 return MAX2(code_begin() + frame_complete_offset(),
234 verified_entry_point() + NativeJump::instruction_size);
235 }
236
237 int CompiledMethod::verify_icholder_relocations() {
238 ResourceMark rm;
239 int count = 0;
240
241 RelocIterator iter(this);
242 while(iter.next()) {
243 if (iter.type() == relocInfo::virtual_call_type) {
244 if (CompiledIC::is_icholder_call_site(iter.virtual_call_reloc(), this)) {
245 CompiledIC *ic = CompiledIC_at(&iter);
246 if (TraceCompiledIC) {
247 tty->print("noticed icholder " INTPTR_FORMAT " ", p2i(ic->cached_icholder()));
248 ic->print();
249 }
250 assert(ic->cached_icholder() != NULL, "must be non-NULL");
251 count++;
252 }
253 }
254 }
255
256 return count;
257 }
258
259 // Method that knows how to preserve outgoing arguments at call. This method must be
260 // called with a frame corresponding to a Java invoke
261 void CompiledMethod::preserve_callee_argument_oops(frame fr, const RegisterMap *reg_map, OopClosure* f) {
262 if (method() != NULL && !method()->is_native()) {
263 address pc = fr.pc();
264 SimpleScopeDesc ssd(this, pc);
265 Bytecode_invoke call(ssd.method(), ssd.bci());
266 bool has_receiver = call.has_receiver();
267 bool has_appendix = call.has_appendix();
268 Symbol* signature = call.signature();
269
270 // The method attached by JIT-compilers should be used, if present.
271 // Bytecode can be inaccurate in such case.
272 Method* callee = attached_method_before_pc(pc);
273 if (callee != NULL) {
274 has_receiver = !(callee->access_flags().is_static());
275 has_appendix = false;
276 signature = callee->signature();
277 }
278
279 fr.oops_compiled_arguments_do(signature, has_receiver, has_appendix, reg_map, f);
280 }
281 }
282
283 Method* CompiledMethod::attached_method(address call_instr) {
284 assert(code_contains(call_instr), "not part of the nmethod");
285 RelocIterator iter(this, call_instr, call_instr + 1);
286 while (iter.next()) {
287 if (iter.addr() == call_instr) {
288 switch(iter.type()) {
289 case relocInfo::static_call_type: return iter.static_call_reloc()->method_value();
290 case relocInfo::opt_virtual_call_type: return iter.opt_virtual_call_reloc()->method_value();
291 case relocInfo::virtual_call_type: return iter.virtual_call_reloc()->method_value();
292 default: break;
293 }
294 }
295 }
296 return NULL; // not found
297 }
298
299 Method* CompiledMethod::attached_method_before_pc(address pc) {
300 if (NativeCall::is_call_before(pc)) {
301 NativeCall* ncall = nativeCall_before(pc);
302 return attached_method(ncall->instruction_address());
303 }
304 return NULL; // not a call
305 }
306
307 void CompiledMethod::clear_inline_caches() {
308 assert(SafepointSynchronize::is_at_safepoint(), "cleaning of IC's only allowed at safepoint");
309 if (is_zombie()) {
310 return;
311 }
312
313 RelocIterator iter(this);
314 while (iter.next()) {
315 iter.reloc()->clear_inline_cache();
316 }
317 }
318
319 // Clear ICStubs of all compiled ICs
320 void CompiledMethod::clear_ic_stubs() {
321 assert_locked_or_safepoint(CompiledIC_lock);
322 ResourceMark rm;
323 RelocIterator iter(this);
324 while(iter.next()) {
325 if (iter.type() == relocInfo::virtual_call_type) {
326 CompiledIC* ic = CompiledIC_at(&iter);
327 ic->clear_ic_stub();
328 }
329 }
330 }
331
332 #ifdef ASSERT
333 // Check class_loader is alive for this bit of metadata.
334 static void check_class(Metadata* md) {
335 Klass* klass = NULL;
336 if (md->is_klass()) {
337 klass = ((Klass*)md);
338 } else if (md->is_method()) {
339 klass = ((Method*)md)->method_holder();
340 } else if (md->is_methodData()) {
341 klass = ((MethodData*)md)->method()->method_holder();
342 } else {
343 md->print();
344 ShouldNotReachHere();
345 }
346 assert(klass->is_loader_alive(), "must be alive");
347 }
348 #endif // ASSERT
349
350
351 void CompiledMethod::clean_ic_if_metadata_is_dead(CompiledIC *ic) {
352 if (ic->is_icholder_call()) {
353 // The only exception is compiledICHolder metdata which may
354 // yet be marked below. (We check this further below).
355 CompiledICHolder* cichk_metdata = ic->cached_icholder();
356
357 if (cichk_metdata->is_loader_alive()) {
358 return;
359 }
360 } else {
361 Metadata* ic_metdata = ic->cached_metadata();
362 if (ic_metdata != NULL) {
363 if (ic_metdata->is_klass()) {
364 if (((Klass*)ic_metdata)->is_loader_alive()) {
365 return;
366 }
367 } else if (ic_metdata->is_method()) {
368 Method* method = (Method*)ic_metdata;
369 assert(!method->is_old(), "old method should have been cleaned");
370 if (method->method_holder()->is_loader_alive()) {
371 return;
372 }
373 } else {
374 ShouldNotReachHere();
375 }
376 }
377 }
378
379 ic->set_to_clean();
380 }
381
382 unsigned char CompiledMethod::_global_unloading_clock = 0;
383
384 void CompiledMethod::increase_unloading_clock() {
385 _global_unloading_clock++;
386 if (_global_unloading_clock == 0) {
387 // _nmethods are allocated with _unloading_clock == 0,
388 // so 0 is never used as a clock value.
389 _global_unloading_clock = 1;
390 }
391 }
392
393 void CompiledMethod::set_unloading_clock(unsigned char unloading_clock) {
394 OrderAccess::release_store(&_unloading_clock, unloading_clock);
395 }
396
397 unsigned char CompiledMethod::unloading_clock() {
398 return OrderAccess::load_acquire(&_unloading_clock);
399 }
400
401
402 // static_stub_Relocations may have dangling references to
403 // nmethods so trim them out here. Otherwise it looks like
404 // compiled code is maintaining a link to dead metadata.
405 void CompiledMethod::clean_ic_stubs() {
406 #ifdef ASSERT
407 address low_boundary = oops_reloc_begin();
408 RelocIterator iter(this, low_boundary);
409 while (iter.next()) {
410 address static_call_addr = NULL;
411 if (iter.type() == relocInfo::opt_virtual_call_type) {
412 CompiledIC* cic = CompiledIC_at(&iter);
413 if (!cic->is_call_to_interpreted()) {
414 static_call_addr = iter.addr();
415 }
416 } else if (iter.type() == relocInfo::static_call_type) {
417 CompiledStaticCall* csc = compiledStaticCall_at(iter.reloc());
418 if (!csc->is_call_to_interpreted()) {
419 static_call_addr = iter.addr();
420 }
421 }
422 if (static_call_addr != NULL) {
423 RelocIterator sciter(this, low_boundary);
424 while (sciter.next()) {
425 if (sciter.type() == relocInfo::static_stub_type &&
426 sciter.static_stub_reloc()->static_call() == static_call_addr) {
427 sciter.static_stub_reloc()->clear_inline_cache();
428 }
429 }
430 }
431 }
432 #endif
433 }
434
435 // This is called at the end of the strong tracing/marking phase of a
436 // GC to unload an nmethod if it contains otherwise unreachable
437 // oops.
438
439 void CompiledMethod::do_unloading(BoolObjectClosure* is_alive) {
440 // Make sure the oop's ready to receive visitors
441 assert(!is_zombie() && !is_unloaded(),
442 "should not call follow on zombie or unloaded nmethod");
443
444 address low_boundary = oops_reloc_begin();
445
446 if (do_unloading_oops(low_boundary, is_alive)) {
447 return;
448 }
449
450 #if INCLUDE_JVMCI
451 if (do_unloading_jvmci()) {
452 return;
453 }
454 #endif
455
456 // Cleanup exception cache and inline caches happens
457 // after all the unloaded methods are found.
458 }
459
460 // Clean references to unloaded nmethods at addr from this one, which is not unloaded.
461 template <class CompiledICorStaticCall>
462 static bool clean_if_nmethod_is_unloaded(CompiledICorStaticCall *ic, address addr, CompiledMethod* from,
463 bool parallel, bool clean_all) {
464 // Ok, to lookup references to zombies here
465 CodeBlob *cb = CodeCache::find_blob_unsafe(addr);
466 CompiledMethod* nm = (cb != NULL) ? cb->as_compiled_method_or_null() : NULL;
467 if (nm != NULL) {
468 if (parallel && nm->unloading_clock() != CompiledMethod::global_unloading_clock()) {
469 // The nmethod has not been processed yet.
470 return true;
471 }
472
473 // Clean inline caches pointing to both zombie and not_entrant methods
474 if (clean_all || !nm->is_in_use() || (nm->method()->code() != nm)) {
475 ic->set_to_clean(from->is_alive());
476 assert(ic->is_clean(), "nmethod " PTR_FORMAT "not clean %s", p2i(from), from->method()->name_and_sig_as_C_string());
477 }
478 }
479
480 return false;
481 }
482
483 static bool clean_if_nmethod_is_unloaded(CompiledIC *ic, CompiledMethod* from,
484 bool parallel, bool clean_all = false) {
485 return clean_if_nmethod_is_unloaded(ic, ic->ic_destination(), from, parallel, clean_all);
486 }
487
488 static bool clean_if_nmethod_is_unloaded(CompiledStaticCall *csc, CompiledMethod* from,
489 bool parallel, bool clean_all = false) {
490 return clean_if_nmethod_is_unloaded(csc, csc->destination(), from, parallel, clean_all);
491 }
492
493 bool CompiledMethod::do_unloading_parallel(BoolObjectClosure* is_alive, bool unloading_occurred) {
494 ResourceMark rm;
495
496 // Make sure the oop's ready to receive visitors
497 assert(!is_zombie() && !is_unloaded(),
498 "should not call follow on zombie or unloaded nmethod");
499
500 address low_boundary = oops_reloc_begin();
501
502 if (do_unloading_oops(low_boundary, is_alive)) {
503 return false;
504 }
505
506 #if INCLUDE_JVMCI
507 if (do_unloading_jvmci()) {
508 return false;
509 }
510 #endif
511
512 return unload_nmethod_caches(/*parallel*/true, unloading_occurred);
513 }
514
515 // Cleans caches in nmethods that point to either classes that are unloaded
516 // or nmethods that are unloaded.
517 //
518 // Can be called either in parallel by G1 currently or after all
519 // nmethods are unloaded. Return postponed=true in the parallel case for
520 // inline caches found that point to nmethods that are not yet visited during
521 // the do_unloading walk.
522 bool CompiledMethod::unload_nmethod_caches(bool parallel, bool unloading_occurred) {
523
524 // Exception cache only needs to be called if unloading occurred
525 if (unloading_occurred) {
526 clean_exception_cache();
527 }
528
529 bool postponed = cleanup_inline_caches_impl(parallel, unloading_occurred, /*clean_all*/false);
530
531 // All static stubs need to be cleaned.
532 clean_ic_stubs();
533
534 // Check that the metadata embedded in the nmethod is alive
535 DEBUG_ONLY(metadata_do(check_class));
536
537 return postponed;
538 }
539
540 // Called to clean up after class unloading for live nmethods and from the sweeper
541 // for all methods.
542 bool CompiledMethod::cleanup_inline_caches_impl(bool parallel, bool unloading_occurred, bool clean_all) {
543 assert_locked_or_safepoint(CompiledIC_lock);
544 bool postponed = false;
545 ResourceMark rm;
546
547 // Find all calls in an nmethod and clear the ones that point to non-entrant,
548 // zombie and unloaded nmethods.
549 RelocIterator iter(this, oops_reloc_begin());
550 while(iter.next()) {
551
552 switch (iter.type()) {
553
554 case relocInfo::virtual_call_type:
555 if (unloading_occurred) {
556 // If class unloading occurred we first clear ICs where the cached metadata
557 // is referring to an unloaded klass or method.
558 clean_ic_if_metadata_is_dead(CompiledIC_at(&iter));
559 }
560
561 postponed |= clean_if_nmethod_is_unloaded(CompiledIC_at(&iter), this, parallel, clean_all);
562 break;
563
564 case relocInfo::opt_virtual_call_type:
565 postponed |= clean_if_nmethod_is_unloaded(CompiledIC_at(&iter), this, parallel, clean_all);
566 break;
567
568 case relocInfo::static_call_type:
569 postponed |= clean_if_nmethod_is_unloaded(compiledStaticCall_at(iter.reloc()), this, parallel, clean_all);
570 break;
571
572 case relocInfo::oop_type:
573 // handled by do_unloading_oops already
574 break;
575
576 case relocInfo::metadata_type:
577 break; // nothing to do.
578
579 default:
580 break;
581 }
582 }
583
584 return postponed;
585 }
586
587 void CompiledMethod::do_unloading_parallel_postponed() {
588 ResourceMark rm;
589
590 // Make sure the oop's ready to receive visitors
591 assert(!is_zombie(),
592 "should not call follow on zombie nmethod");
593
594 RelocIterator iter(this, oops_reloc_begin());
595 while(iter.next()) {
596
597 switch (iter.type()) {
598
599 case relocInfo::virtual_call_type:
600 clean_if_nmethod_is_unloaded(CompiledIC_at(&iter), this, true);
601 break;
602
603 case relocInfo::opt_virtual_call_type:
604 clean_if_nmethod_is_unloaded(CompiledIC_at(&iter), this, true);
605 break;
606
607 case relocInfo::static_call_type:
608 clean_if_nmethod_is_unloaded(compiledStaticCall_at(iter.reloc()), this, true);
609 break;
610
611 default:
612 break;
613 }
614 }
615 }
616
617 // Iterating over all nmethods, e.g. with the help of CodeCache::nmethods_do(fun) was found
618 // to not be inherently safe. There is a chance that fields are seen which are not properly
619 // initialized. This happens despite the fact that nmethods_do() asserts the CodeCache_lock
620 // to be held.
621 // To bundle knowledge about necessary checks in one place, this function was introduced.
622 // It is not claimed that these checks are sufficient, but they were found to be necessary.
623 bool CompiledMethod::nmethod_access_is_safe(nmethod* nm) {
624 Method* method = (nm == NULL) ? NULL : nm->method(); // nm->method() may be uninitialized, i.e. != NULL, but invalid
625 return (nm != NULL) && (method != NULL) && (method->signature() != NULL) &&
626 !nm->is_zombie() && !nm->is_not_installed() &&
627 os::is_readable_pointer(method) &&
628 os::is_readable_pointer(method->constants()) &&
629 os::is_readable_pointer(method->signature());
630 }