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 }