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 _method(method), _mark_for_deoptimization_status(not_marked) { 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 _method(method), _mark_for_deoptimization_status(not_marked) { 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 IC callsites, releasing ICStubs of all compiled ICs 326 // as well as any associated CompiledICHolders. 327 void CompiledMethod::clear_ic_callsites() { 328 assert_locked_or_safepoint(CompiledIC_lock); 329 ResourceMark rm; 330 RelocIterator iter(this); 331 while(iter.next()) { 332 if (iter.type() == relocInfo::virtual_call_type) { 333 CompiledIC* ic = CompiledIC_at(&iter); 334 ic->set_to_clean(false); 335 } 336 } 337 } 338 339 #ifdef ASSERT 340 // Check class_loader is alive for this bit of metadata. 341 static void check_class(Metadata* md) { 342 Klass* klass = NULL; 343 if (md->is_klass()) { 344 klass = ((Klass*)md); 345 } else if (md->is_method()) { 346 klass = ((Method*)md)->method_holder(); 347 } else if (md->is_methodData()) { 348 klass = ((MethodData*)md)->method()->method_holder(); 349 } else { 350 md->print(); 351 ShouldNotReachHere(); 352 } 353 assert(klass->is_loader_alive(), "must be alive"); 354 } 355 #endif // ASSERT 356 357 358 void CompiledMethod::clean_ic_if_metadata_is_dead(CompiledIC *ic) { 359 if (ic->is_icholder_call()) { 360 // The only exception is compiledICHolder metdata which may 361 // yet be marked below. (We check this further below). 362 CompiledICHolder* cichk_metdata = ic->cached_icholder(); 363 364 if (cichk_metdata->is_loader_alive()) { 365 return; 366 } 367 } else { 368 Metadata* ic_metdata = ic->cached_metadata(); 369 if (ic_metdata != NULL) { 370 if (ic_metdata->is_klass()) { 371 if (((Klass*)ic_metdata)->is_loader_alive()) { 372 return; 373 } 374 } else if (ic_metdata->is_method()) { 375 Method* method = (Method*)ic_metdata; 376 assert(!method->is_old(), "old method should have been cleaned"); 377 if (method->method_holder()->is_loader_alive()) { 378 return; 379 } 380 } else { 381 ShouldNotReachHere(); 382 } 383 } 384 } 385 386 ic->set_to_clean(); 387 } 388 389 unsigned char CompiledMethod::_global_unloading_clock = 0; 390 391 void CompiledMethod::increase_unloading_clock() { 392 _global_unloading_clock++; 393 if (_global_unloading_clock == 0) { 394 // _nmethods are allocated with _unloading_clock == 0, 395 // so 0 is never used as a clock value. 396 _global_unloading_clock = 1; 397 } 398 } 399 400 void CompiledMethod::set_unloading_clock(unsigned char unloading_clock) { 401 OrderAccess::release_store(&_unloading_clock, unloading_clock); 402 } 403 404 unsigned char CompiledMethod::unloading_clock() { 405 return OrderAccess::load_acquire(&_unloading_clock); 406 } 407 408 409 // static_stub_Relocations may have dangling references to 410 // nmethods so trim them out here. Otherwise it looks like 411 // compiled code is maintaining a link to dead metadata. 412 void CompiledMethod::clean_ic_stubs() { 413 #ifdef ASSERT 414 address low_boundary = oops_reloc_begin(); 415 RelocIterator iter(this, low_boundary); 416 while (iter.next()) { 417 address static_call_addr = NULL; 418 if (iter.type() == relocInfo::opt_virtual_call_type) { 419 CompiledIC* cic = CompiledIC_at(&iter); 420 if (!cic->is_call_to_interpreted()) { 421 static_call_addr = iter.addr(); 422 } 423 } else if (iter.type() == relocInfo::static_call_type) { 424 CompiledStaticCall* csc = compiledStaticCall_at(iter.reloc()); 425 if (!csc->is_call_to_interpreted()) { 426 static_call_addr = iter.addr(); 427 } 428 } 429 if (static_call_addr != NULL) { 430 RelocIterator sciter(this, low_boundary); 431 while (sciter.next()) { 432 if (sciter.type() == relocInfo::static_stub_type && 433 sciter.static_stub_reloc()->static_call() == static_call_addr) { 434 sciter.static_stub_reloc()->clear_inline_cache(); 435 } 436 } 437 } 438 } 439 #endif 440 } 441 442 // This is called at the end of the strong tracing/marking phase of a 443 // GC to unload an nmethod if it contains otherwise unreachable 444 // oops. 445 446 void CompiledMethod::do_unloading(BoolObjectClosure* is_alive) { 447 // Make sure the oop's ready to receive visitors 448 assert(!is_zombie() && !is_unloaded(), 449 "should not call follow on zombie or unloaded nmethod"); 450 451 address low_boundary = oops_reloc_begin(); 452 453 if (do_unloading_oops(low_boundary, is_alive)) { 454 return; 455 } 456 457 #if INCLUDE_JVMCI 458 if (do_unloading_jvmci()) { 459 return; 460 } 461 #endif 462 463 // Cleanup exception cache and inline caches happens 464 // after all the unloaded methods are found. 465 } 466 467 // Clean references to unloaded nmethods at addr from this one, which is not unloaded. 468 template <class CompiledICorStaticCall> 469 static bool clean_if_nmethod_is_unloaded(CompiledICorStaticCall *ic, address addr, CompiledMethod* from, 470 bool parallel, bool clean_all) { 471 // Ok, to lookup references to zombies here 472 CodeBlob *cb = CodeCache::find_blob_unsafe(addr); 473 CompiledMethod* nm = (cb != NULL) ? cb->as_compiled_method_or_null() : NULL; 474 if (nm != NULL) { 475 if (parallel && nm->unloading_clock() != CompiledMethod::global_unloading_clock()) { 476 // The nmethod has not been processed yet. 477 return true; 478 } 479 480 // Clean inline caches pointing to both zombie and not_entrant methods 481 if (clean_all || !nm->is_in_use() || (nm->method()->code() != nm)) { 482 ic->set_to_clean(from->is_alive()); 483 assert(ic->is_clean(), "nmethod " PTR_FORMAT "not clean %s", p2i(from), from->method()->name_and_sig_as_C_string()); 484 } 485 } 486 487 return false; 488 } 489 490 static bool clean_if_nmethod_is_unloaded(CompiledIC *ic, CompiledMethod* from, 491 bool parallel, bool clean_all = false) { 492 return clean_if_nmethod_is_unloaded(ic, ic->ic_destination(), from, parallel, clean_all); 493 } 494 495 static bool clean_if_nmethod_is_unloaded(CompiledStaticCall *csc, CompiledMethod* from, 496 bool parallel, bool clean_all = false) { 497 return clean_if_nmethod_is_unloaded(csc, csc->destination(), from, parallel, clean_all); 498 } 499 500 bool CompiledMethod::do_unloading_parallel(BoolObjectClosure* is_alive, bool unloading_occurred) { 501 ResourceMark rm; 502 503 // Make sure the oop's ready to receive visitors 504 assert(!is_zombie() && !is_unloaded(), 505 "should not call follow on zombie or unloaded nmethod"); 506 507 address low_boundary = oops_reloc_begin(); 508 509 if (do_unloading_oops(low_boundary, is_alive)) { 510 return false; 511 } 512 513 #if INCLUDE_JVMCI 514 if (do_unloading_jvmci()) { 515 return false; 516 } 517 #endif 518 519 return unload_nmethod_caches(/*parallel*/true, unloading_occurred); 520 } 521 522 // Cleans caches in nmethods that point to either classes that are unloaded 523 // or nmethods that are unloaded. 524 // 525 // Can be called either in parallel by G1 currently or after all 526 // nmethods are unloaded. Return postponed=true in the parallel case for 527 // inline caches found that point to nmethods that are not yet visited during 528 // the do_unloading walk. 529 bool CompiledMethod::unload_nmethod_caches(bool parallel, bool unloading_occurred) { 530 531 // Exception cache only needs to be called if unloading occurred 532 if (unloading_occurred) { 533 clean_exception_cache(); 534 } 535 536 bool postponed = cleanup_inline_caches_impl(parallel, unloading_occurred, /*clean_all*/false); 537 538 // All static stubs need to be cleaned. 539 clean_ic_stubs(); 540 541 // Check that the metadata embedded in the nmethod is alive 542 DEBUG_ONLY(metadata_do(check_class)); 543 544 return postponed; 545 } 546 547 // Called to clean up after class unloading for live nmethods and from the sweeper 548 // for all methods. 549 bool CompiledMethod::cleanup_inline_caches_impl(bool parallel, bool unloading_occurred, bool clean_all) { 550 assert_locked_or_safepoint(CompiledIC_lock); 551 bool postponed = false; 552 ResourceMark rm; 553 554 // Find all calls in an nmethod and clear the ones that point to non-entrant, 555 // zombie and unloaded nmethods. 556 RelocIterator iter(this, oops_reloc_begin()); 557 while(iter.next()) { 558 559 switch (iter.type()) { 560 561 case relocInfo::virtual_call_type: 562 if (unloading_occurred) { 563 // If class unloading occurred we first clear ICs where the cached metadata 564 // is referring to an unloaded klass or method. 565 clean_ic_if_metadata_is_dead(CompiledIC_at(&iter)); 566 } 567 568 postponed |= clean_if_nmethod_is_unloaded(CompiledIC_at(&iter), this, parallel, clean_all); 569 break; 570 571 case relocInfo::opt_virtual_call_type: 572 postponed |= clean_if_nmethod_is_unloaded(CompiledIC_at(&iter), this, parallel, clean_all); 573 break; 574 575 case relocInfo::static_call_type: 576 postponed |= clean_if_nmethod_is_unloaded(compiledStaticCall_at(iter.reloc()), this, parallel, clean_all); 577 break; 578 579 case relocInfo::oop_type: 580 // handled by do_unloading_oops already 581 break; 582 583 case relocInfo::metadata_type: 584 break; // nothing to do. 585 586 default: 587 break; 588 } 589 } 590 591 return postponed; 592 } 593 594 void CompiledMethod::do_unloading_parallel_postponed() { 595 ResourceMark rm; 596 597 // Make sure the oop's ready to receive visitors 598 assert(!is_zombie(), 599 "should not call follow on zombie nmethod"); 600 601 RelocIterator iter(this, oops_reloc_begin()); 602 while(iter.next()) { 603 604 switch (iter.type()) { 605 606 case relocInfo::virtual_call_type: 607 clean_if_nmethod_is_unloaded(CompiledIC_at(&iter), this, true); 608 break; 609 610 case relocInfo::opt_virtual_call_type: 611 clean_if_nmethod_is_unloaded(CompiledIC_at(&iter), this, true); 612 break; 613 614 case relocInfo::static_call_type: 615 clean_if_nmethod_is_unloaded(compiledStaticCall_at(iter.reloc()), this, true); 616 break; 617 618 default: 619 break; 620 } 621 } 622 } 623 624 // Iterating over all nmethods, e.g. with the help of CodeCache::nmethods_do(fun) was found 625 // to not be inherently safe. There is a chance that fields are seen which are not properly 626 // initialized. This happens despite the fact that nmethods_do() asserts the CodeCache_lock 627 // to be held. 628 // To bundle knowledge about necessary checks in one place, this function was introduced. 629 // It is not claimed that these checks are sufficient, but they were found to be necessary. 630 bool CompiledMethod::nmethod_access_is_safe(nmethod* nm) { 631 Method* method = (nm == NULL) ? NULL : nm->method(); // nm->method() may be uninitialized, i.e. != NULL, but invalid 632 return (nm != NULL) && (method != NULL) && (method->signature() != NULL) && 633 !nm->is_zombie() && !nm->is_not_installed() && 634 os::is_readable_pointer(method) && 635 os::is_readable_pointer(method->constants()) && 636 os::is_readable_pointer(method->signature()); 637 }