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. If an oop in the old code was there, that oop
230 // should not get GC'd. Skip the first few bytes of oops on
231 // not-entrant methods.
232 address low_boundary = verified_entry_point();
233 if (!is_in_use() && is_nmethod()) {
234 low_boundary += NativeJump::instruction_size;
235 // %%% Note: On SPARC we patch only a 4-byte trap, not a full NativeJump.
236 // This means that the low_boundary is going to be a little too high.
237 // This shouldn't matter, since oops of non-entrant methods are never used.
238 // In fact, why are we bothering to look at oops in a non-entrant method??
239 }
240 return low_boundary;
241 }
242
243 int CompiledMethod::verify_icholder_relocations() {
244 ResourceMark rm;
245 int count = 0;
246
247 RelocIterator iter(this);
248 while(iter.next()) {
249 if (iter.type() == relocInfo::virtual_call_type) {
250 if (CompiledIC::is_icholder_call_site(iter.virtual_call_reloc(), this)) {
251 CompiledIC *ic = CompiledIC_at(&iter);
252 if (TraceCompiledIC) {
253 tty->print("noticed icholder " INTPTR_FORMAT " ", p2i(ic->cached_icholder()));
254 ic->print();
255 }
256 assert(ic->cached_icholder() != NULL, "must be non-NULL");
257 count++;
258 }
259 }
260 }
261
262 return count;
263 }
264
265 // Method that knows how to preserve outgoing arguments at call. This method must be
266 // called with a frame corresponding to a Java invoke
267 void CompiledMethod::preserve_callee_argument_oops(frame fr, const RegisterMap *reg_map, OopClosure* f) {
268 if (method() != NULL && !method()->is_native()) {
269 address pc = fr.pc();
270 SimpleScopeDesc ssd(this, pc);
271 Bytecode_invoke call(ssd.method(), ssd.bci());
272 bool has_receiver = call.has_receiver();
273 bool has_appendix = call.has_appendix();
274 Symbol* signature = call.signature();
275
276 // The method attached by JIT-compilers should be used, if present.
277 // Bytecode can be inaccurate in such case.
278 Method* callee = attached_method_before_pc(pc);
279 if (callee != NULL) {
280 has_receiver = !(callee->access_flags().is_static());
281 has_appendix = false;
282 signature = callee->signature();
283 }
284
285 fr.oops_compiled_arguments_do(signature, has_receiver, has_appendix, reg_map, f);
286 }
287 }
288
289 Method* CompiledMethod::attached_method(address call_instr) {
290 assert(code_contains(call_instr), "not part of the nmethod");
291 RelocIterator iter(this, call_instr, call_instr + 1);
292 while (iter.next()) {
293 if (iter.addr() == call_instr) {
294 switch(iter.type()) {
295 case relocInfo::static_call_type: return iter.static_call_reloc()->method_value();
296 case relocInfo::opt_virtual_call_type: return iter.opt_virtual_call_reloc()->method_value();
297 case relocInfo::virtual_call_type: return iter.virtual_call_reloc()->method_value();
298 default: break;
299 }
300 }
301 }
302 return NULL; // not found
303 }
304
305 Method* CompiledMethod::attached_method_before_pc(address pc) {
306 if (NativeCall::is_call_before(pc)) {
307 NativeCall* ncall = nativeCall_before(pc);
308 return attached_method(ncall->instruction_address());
309 }
310 return NULL; // not a call
311 }
312
313 void CompiledMethod::clear_inline_caches() {
314 assert(SafepointSynchronize::is_at_safepoint(), "cleaning of IC's only allowed at safepoint");
315 if (is_zombie()) {
316 return;
317 }
318
319 RelocIterator iter(this);
320 while (iter.next()) {
321 iter.reloc()->clear_inline_cache();
322 }
323 }
324
325 // Clear ICStubs of all compiled ICs
326 void CompiledMethod::clear_ic_stubs() {
327 assert_locked_or_safepoint(CompiledIC_lock);
328 ResourceMark rm;
329 RelocIterator iter(this);
330 while(iter.next()) {
331 if (iter.type() == relocInfo::virtual_call_type) {
332 CompiledIC* ic = CompiledIC_at(&iter);
333 ic->clear_ic_stub();
334 }
335 }
336 }
337
338 #ifdef ASSERT
339 // Check class_loader is alive for this bit of metadata.
340 static void check_class(Metadata* md) {
341 Klass* klass = NULL;
342 if (md->is_klass()) {
343 klass = ((Klass*)md);
344 } else if (md->is_method()) {
345 klass = ((Method*)md)->method_holder();
346 } else if (md->is_methodData()) {
347 klass = ((MethodData*)md)->method()->method_holder();
348 } else {
349 md->print();
350 ShouldNotReachHere();
351 }
352 assert(klass->is_loader_alive(), "must be alive");
353 }
354 #endif // ASSERT
355
356
357 void CompiledMethod::clean_ic_if_metadata_is_dead(CompiledIC *ic) {
358 if (ic->is_icholder_call()) {
359 // The only exception is compiledICHolder metdata which may
360 // yet be marked below. (We check this further below).
361 CompiledICHolder* cichk_metdata = ic->cached_icholder();
362
363 if (cichk_metdata->is_loader_alive()) {
364 return;
365 }
366 } else {
367 Metadata* ic_metdata = ic->cached_metadata();
368 if (ic_metdata != NULL) {
369 if (ic_metdata->is_klass()) {
370 if (((Klass*)ic_metdata)->is_loader_alive()) {
371 return;
372 }
373 } else if (ic_metdata->is_method()) {
374 Method* method = (Method*)ic_metdata;
375 assert(!method->is_old(), "old method should have been cleaned");
376 if (method->method_holder()->is_loader_alive()) {
377 return;
378 }
379 } else {
380 ShouldNotReachHere();
381 }
382 }
383 }
384
385 ic->set_to_clean();
386 }
387
388 unsigned char CompiledMethod::_global_unloading_clock = 0;
389
390 void CompiledMethod::increase_unloading_clock() {
391 _global_unloading_clock++;
392 if (_global_unloading_clock == 0) {
393 // _nmethods are allocated with _unloading_clock == 0,
394 // so 0 is never used as a clock value.
395 _global_unloading_clock = 1;
396 }
397 }
398
399 void CompiledMethod::set_unloading_clock(unsigned char unloading_clock) {
400 OrderAccess::release_store(&_unloading_clock, unloading_clock);
401 }
402
403 unsigned char CompiledMethod::unloading_clock() {
404 return OrderAccess::load_acquire(&_unloading_clock);
405 }
406
407
408 // static_stub_Relocations may have dangling references to
409 // nmethods so trim them out here. Otherwise it looks like
410 // compiled code is maintaining a link to dead metadata.
411 void CompiledMethod::clean_ic_stubs() {
412 #ifdef ASSERT
413 address low_boundary = oops_reloc_begin();
414 RelocIterator iter(this, low_boundary);
415 while (iter.next()) {
416 address static_call_addr = NULL;
417 if (iter.type() == relocInfo::opt_virtual_call_type) {
418 CompiledIC* cic = CompiledIC_at(&iter);
419 if (!cic->is_call_to_interpreted()) {
420 static_call_addr = iter.addr();
421 }
422 } else if (iter.type() == relocInfo::static_call_type) {
423 CompiledStaticCall* csc = compiledStaticCall_at(iter.reloc());
424 if (!csc->is_call_to_interpreted()) {
425 static_call_addr = iter.addr();
426 }
427 }
428 if (static_call_addr != NULL) {
429 RelocIterator sciter(this, low_boundary);
430 while (sciter.next()) {
431 if (sciter.type() == relocInfo::static_stub_type &&
432 sciter.static_stub_reloc()->static_call() == static_call_addr) {
433 sciter.static_stub_reloc()->clear_inline_cache();
434 }
435 }
436 }
437 }
438 #endif
439 }
440
441 // This is called at the end of the strong tracing/marking phase of a
442 // GC to unload an nmethod if it contains otherwise unreachable
443 // oops.
444
445 void CompiledMethod::do_unloading(BoolObjectClosure* is_alive) {
446 // Make sure the oop's ready to receive visitors
447 assert(!is_zombie() && !is_unloaded(),
448 "should not call follow on zombie or unloaded nmethod");
449
450 address low_boundary = oops_reloc_begin();
451
452 if (do_unloading_oops(low_boundary, is_alive)) {
453 return;
454 }
455
456 #if INCLUDE_JVMCI
457 if (do_unloading_jvmci()) {
458 return;
459 }
460 #endif
461
462 // Cleanup exception cache and inline caches happens
463 // after all the unloaded methods are found.
464 }
465
466 // Clean references to unloaded nmethods at addr from this one, which is not unloaded.
467 template <class CompiledICorStaticCall>
468 static bool clean_if_nmethod_is_unloaded(CompiledICorStaticCall *ic, address addr, CompiledMethod* from,
469 bool parallel, bool clean_all) {
470 // Ok, to lookup references to zombies here
471 CodeBlob *cb = CodeCache::find_blob_unsafe(addr);
472 CompiledMethod* nm = (cb != NULL) ? cb->as_compiled_method_or_null() : NULL;
473 if (nm != NULL) {
474 if (parallel && nm->unloading_clock() != CompiledMethod::global_unloading_clock()) {
475 // The nmethod has not been processed yet.
476 return true;
477 }
478
479 // Clean inline caches pointing to both zombie and not_entrant methods
480 if (clean_all || !nm->is_in_use() || (nm->method()->code() != nm)) {
481 ic->set_to_clean(from->is_alive());
482 assert(ic->is_clean(), "nmethod " PTR_FORMAT "not clean %s", p2i(from), from->method()->name_and_sig_as_C_string());
483 }
484 }
485
486 return false;
487 }
488
489 static bool clean_if_nmethod_is_unloaded(CompiledIC *ic, CompiledMethod* from,
490 bool parallel, bool clean_all = false) {
491 return clean_if_nmethod_is_unloaded(ic, ic->ic_destination(), from, parallel, clean_all);
492 }
493
494 static bool clean_if_nmethod_is_unloaded(CompiledStaticCall *csc, CompiledMethod* from,
495 bool parallel, bool clean_all = false) {
496 return clean_if_nmethod_is_unloaded(csc, csc->destination(), from, parallel, clean_all);
497 }
498
499 bool CompiledMethod::do_unloading_parallel(BoolObjectClosure* is_alive, bool unloading_occurred) {
500 ResourceMark rm;
501
502 // Make sure the oop's ready to receive visitors
503 assert(!is_zombie() && !is_unloaded(),
504 "should not call follow on zombie or unloaded nmethod");
505
506 address low_boundary = oops_reloc_begin();
507
508 if (do_unloading_oops(low_boundary, is_alive)) {
509 return false;
510 }
511
512 #if INCLUDE_JVMCI
513 if (do_unloading_jvmci()) {
514 return false;
515 }
516 #endif
517
518 return unload_nmethod_caches(/*parallel*/true, unloading_occurred);
519 }
520
521 // Cleans caches in nmethods that point to either classes that are unloaded
522 // or nmethods that are unloaded.
523 //
524 // Can be called either in parallel by G1 currently or after all
525 // nmethods are unloaded. Return postponed=true in the parallel case for
526 // inline caches found that point to nmethods that are not yet visited during
527 // the do_unloading walk.
528 bool CompiledMethod::unload_nmethod_caches(bool parallel, bool unloading_occurred) {
529
530 // Exception cache only needs to be called if unloading occurred
531 if (unloading_occurred) {
532 clean_exception_cache();
533 }
534
535 bool postponed = cleanup_inline_caches_impl(parallel, unloading_occurred, /*clean_all*/false);
536
537 // All static stubs need to be cleaned.
538 clean_ic_stubs();
539
540 // Check that the metadata embedded in the nmethod is alive
541 DEBUG_ONLY(metadata_do(check_class));
542
543 return postponed;
544 }
545
546 // Called to clean up after class unloading for live nmethods and from the sweeper
547 // for all methods.
548 bool CompiledMethod::cleanup_inline_caches_impl(bool parallel, bool unloading_occurred, bool clean_all) {
549 assert_locked_or_safepoint(CompiledIC_lock);
550 bool postponed = false;
551 ResourceMark rm;
552
553 // Find all calls in an nmethod and clear the ones that point to non-entrant,
554 // zombie and unloaded nmethods.
555 RelocIterator iter(this, oops_reloc_begin());
556 while(iter.next()) {
557
558 switch (iter.type()) {
559
560 case relocInfo::virtual_call_type:
561 if (unloading_occurred) {
562 // If class unloading occurred we first clear ICs where the cached metadata
563 // is referring to an unloaded klass or method.
564 clean_ic_if_metadata_is_dead(CompiledIC_at(&iter));
565 }
566
567 postponed |= clean_if_nmethod_is_unloaded(CompiledIC_at(&iter), this, parallel, clean_all);
568 break;
569
570 case relocInfo::opt_virtual_call_type:
571 postponed |= clean_if_nmethod_is_unloaded(CompiledIC_at(&iter), this, parallel, clean_all);
572 break;
573
574 case relocInfo::static_call_type:
575 postponed |= clean_if_nmethod_is_unloaded(compiledStaticCall_at(iter.reloc()), this, parallel, clean_all);
576 break;
577
578 case relocInfo::oop_type:
579 // handled by do_unloading_oops already
580 break;
581
582 case relocInfo::metadata_type:
583 break; // nothing to do.
584
585 default:
586 break;
587 }
588 }
589
590 return postponed;
591 }
592
593 void CompiledMethod::do_unloading_parallel_postponed() {
594 ResourceMark rm;
595
596 // Make sure the oop's ready to receive visitors
597 assert(!is_zombie(),
598 "should not call follow on zombie nmethod");
599
600 RelocIterator iter(this, oops_reloc_begin());
601 while(iter.next()) {
602
603 switch (iter.type()) {
604
605 case relocInfo::virtual_call_type:
606 clean_if_nmethod_is_unloaded(CompiledIC_at(&iter), this, true);
607 break;
608
609 case relocInfo::opt_virtual_call_type:
610 clean_if_nmethod_is_unloaded(CompiledIC_at(&iter), this, true);
611 break;
612
613 case relocInfo::static_call_type:
614 clean_if_nmethod_is_unloaded(compiledStaticCall_at(iter.reloc()), this, true);
615 break;
616
617 default:
618 break;
619 }
620 }
621 }
622
623 // Iterating over all nmethods, e.g. with the help of CodeCache::nmethods_do(fun) was found
624 // to not be inherently safe. There is a chance that fields are seen which are not properly
625 // initialized. This happens despite the fact that nmethods_do() asserts the CodeCache_lock
626 // to be held.
627 // To bundle knowledge about necessary checks in one place, this function was introduced.
628 // It is not claimed that these checks are sufficient, but they were found to be necessary.
629 bool CompiledMethod::nmethod_access_is_safe(nmethod* nm) {
630 Method* method = (nm == NULL) ? NULL : nm->method(); // nm->method() may be uninitialized, i.e. != NULL, but invalid
631 return (nm != NULL) && (method != NULL) && (method->signature() != NULL) &&
632 !nm->is_zombie() && !nm->is_not_installed() &&
633 os::is_readable_pointer(method) &&
634 os::is_readable_pointer(method->constants()) &&
635 os::is_readable_pointer(method->signature());
636 }