1 /*
   2  * Copyright (c) 1997, 2026, 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 "asm/assembler.inline.hpp"
  26 #include "cds/cdsConfig.hpp"
  27 #include "code/codeCache.hpp"
  28 #include "code/compiledIC.hpp"
  29 #include "code/dependencies.hpp"
  30 #include "code/nativeInst.hpp"
  31 #include "code/nmethod.inline.hpp"
  32 #include "code/scopeDesc.hpp"
  33 #include "compiler/abstractCompiler.hpp"
  34 #include "compiler/compilationLog.hpp"
  35 #include "compiler/compileBroker.hpp"
  36 #include "compiler/compileLog.hpp"
  37 #include "compiler/compilerDirectives.hpp"
  38 #include "compiler/compilerOracle.hpp"
  39 #include "compiler/compileTask.hpp"
  40 #include "compiler/directivesParser.hpp"
  41 #include "compiler/disassembler.hpp"
  42 #include "compiler/oopMap.inline.hpp"
  43 #include "gc/shared/barrierSet.hpp"
  44 #include "gc/shared/barrierSetNMethod.hpp"
  45 #include "gc/shared/classUnloadingContext.hpp"
  46 #include "gc/shared/collectedHeap.hpp"
  47 #include "interpreter/bytecode.inline.hpp"
  48 #include "jvm.h"
  49 #include "logging/log.hpp"
  50 #include "logging/logStream.hpp"
  51 #include "memory/allocation.inline.hpp"
  52 #include "memory/resourceArea.hpp"
  53 #include "memory/universe.hpp"
  54 #include "oops/access.inline.hpp"
  55 #include "oops/klass.inline.hpp"
  56 #include "oops/method.inline.hpp"
  57 #include "oops/methodData.hpp"
  58 #include "oops/oop.inline.hpp"
  59 #include "oops/weakHandle.inline.hpp"
  60 #include "prims/jvmtiImpl.hpp"
  61 #include "prims/jvmtiThreadState.hpp"
  62 #include "prims/methodHandles.hpp"
  63 #include "runtime/atomicAccess.hpp"
  64 #include "runtime/continuation.hpp"
  65 #include "runtime/deoptimization.hpp"
  66 #include "runtime/flags/flagSetting.hpp"
  67 #include "runtime/frame.inline.hpp"
  68 #include "runtime/handles.inline.hpp"
  69 #include "runtime/icache.hpp"
  70 #include "runtime/jniHandles.inline.hpp"
  71 #include "runtime/orderAccess.hpp"
  72 #include "runtime/os.hpp"
  73 #include "runtime/safepointVerifiers.hpp"
  74 #include "runtime/serviceThread.hpp"
  75 #include "runtime/sharedRuntime.hpp"
  76 #include "runtime/signature.hpp"
  77 #include "runtime/threadWXSetters.inline.hpp"
  78 #include "runtime/vmThread.hpp"
  79 #include "utilities/align.hpp"
  80 #include "utilities/copy.hpp"
  81 #include "utilities/dtrace.hpp"
  82 #include "utilities/events.hpp"
  83 #include "utilities/globalDefinitions.hpp"
  84 #include "utilities/hashTable.hpp"
  85 #include "utilities/xmlstream.hpp"
  86 #if INCLUDE_JVMCI
  87 #include "jvmci/jvmciRuntime.hpp"
  88 #endif
  89 
  90 #ifdef DTRACE_ENABLED
  91 
  92 // Only bother with this argument setup if dtrace is available
  93 
  94 #define DTRACE_METHOD_UNLOAD_PROBE(method)                                \
  95   {                                                                       \
  96     Method* m = (method);                                                 \
  97     if (m != nullptr) {                                                   \
  98       Symbol* klass_name = m->klass_name();                               \
  99       Symbol* name = m->name();                                           \
 100       Symbol* signature = m->signature();                                 \
 101       HOTSPOT_COMPILED_METHOD_UNLOAD(                                     \
 102         (char *) klass_name->bytes(), klass_name->utf8_length(),          \
 103         (char *) name->bytes(), name->utf8_length(),                      \
 104         (char *) signature->bytes(), signature->utf8_length());           \
 105     }                                                                     \
 106   }
 107 
 108 #else //  ndef DTRACE_ENABLED
 109 
 110 #define DTRACE_METHOD_UNLOAD_PROBE(method)
 111 
 112 #endif
 113 
 114 // Cast from int value to narrow type
 115 #define CHECKED_CAST(result, T, thing)      \
 116   result = static_cast<T>(thing); \
 117   guarantee(static_cast<int>(result) == thing, "failed: %d != %d", static_cast<int>(result), thing);
 118 
 119 //---------------------------------------------------------------------------------
 120 // NMethod statistics
 121 // They are printed under various flags, including:
 122 //   PrintC1Statistics, PrintOptoStatistics, LogVMOutput, and LogCompilation.
 123 // (In the latter two cases, they like other stats are printed to the log only.)
 124 
 125 #ifndef PRODUCT
 126 // These variables are put into one block to reduce relocations
 127 // and make it simpler to print from the debugger.
 128 struct java_nmethod_stats_struct {
 129   uint nmethod_count;
 130   uint total_nm_size;
 131   uint total_immut_size;
 132   uint total_mut_size;
 133   uint relocation_size;
 134   uint consts_size;
 135   uint insts_size;
 136   uint stub_size;
 137   uint oops_size;
 138   uint metadata_size;
 139   uint dependencies_size;
 140   uint nul_chk_table_size;
 141   uint handler_table_size;
 142   uint scopes_pcs_size;
 143   uint scopes_data_size;
 144 #if INCLUDE_JVMCI
 145   uint speculations_size;
 146   uint jvmci_data_size;
 147 #endif
 148 
 149   void note_nmethod(nmethod* nm) {
 150     nmethod_count += 1;
 151     total_nm_size       += nm->size();
 152     total_immut_size    += nm->immutable_data_size();
 153     total_mut_size      += nm->mutable_data_size();
 154     relocation_size     += nm->relocation_size();
 155     consts_size         += nm->consts_size();
 156     insts_size          += nm->insts_size();
 157     stub_size           += nm->stub_size();
 158     oops_size           += nm->oops_size();
 159     metadata_size       += nm->metadata_size();
 160     scopes_data_size    += nm->scopes_data_size();
 161     scopes_pcs_size     += nm->scopes_pcs_size();
 162     dependencies_size   += nm->dependencies_size();
 163     handler_table_size  += nm->handler_table_size();
 164     nul_chk_table_size  += nm->nul_chk_table_size();
 165 #if INCLUDE_JVMCI
 166     speculations_size   += nm->speculations_size();
 167     jvmci_data_size     += nm->jvmci_data_size();
 168 #endif
 169   }
 170   void print_nmethod_stats(const char* name) {
 171     if (nmethod_count == 0)  return;
 172     tty->print_cr("Statistics for %u bytecoded nmethods for %s:", nmethod_count, name);
 173     uint total_size = total_nm_size + total_immut_size + total_mut_size;
 174     if (total_nm_size != 0) {
 175       tty->print_cr(" total size      = %u (100%%)", total_size);
 176       tty->print_cr(" in CodeCache    = %u (%f%%)", total_nm_size, (total_nm_size * 100.0f)/total_size);
 177     }
 178     uint header_size = (uint)(nmethod_count * sizeof(nmethod));
 179     if (nmethod_count != 0) {
 180       tty->print_cr("   header        = %u (%f%%)", header_size, (header_size * 100.0f)/total_nm_size);
 181     }
 182     if (consts_size != 0) {
 183       tty->print_cr("   constants     = %u (%f%%)", consts_size, (consts_size * 100.0f)/total_nm_size);
 184     }
 185     if (insts_size != 0) {
 186       tty->print_cr("   main code     = %u (%f%%)", insts_size, (insts_size * 100.0f)/total_nm_size);
 187     }
 188     if (stub_size != 0) {
 189       tty->print_cr("   stub code     = %u (%f%%)", stub_size, (stub_size * 100.0f)/total_nm_size);
 190     }
 191     if (oops_size != 0) {
 192       tty->print_cr("   oops          = %u (%f%%)", oops_size, (oops_size * 100.0f)/total_nm_size);
 193     }
 194     if (total_mut_size != 0) {
 195       tty->print_cr(" mutable data    = %u (%f%%)", total_mut_size, (total_mut_size * 100.0f)/total_size);
 196     }
 197     if (relocation_size != 0) {
 198       tty->print_cr("   relocation    = %u (%f%%)", relocation_size, (relocation_size * 100.0f)/total_mut_size);
 199     }
 200     if (metadata_size != 0) {
 201       tty->print_cr("   metadata      = %u (%f%%)", metadata_size, (metadata_size * 100.0f)/total_mut_size);
 202     }
 203 #if INCLUDE_JVMCI
 204     if (jvmci_data_size != 0) {
 205       tty->print_cr("   JVMCI data    = %u (%f%%)", jvmci_data_size, (jvmci_data_size * 100.0f)/total_mut_size);
 206     }
 207 #endif
 208     if (total_immut_size != 0) {
 209       tty->print_cr(" immutable data  = %u (%f%%)", total_immut_size, (total_immut_size * 100.0f)/total_size);
 210     }
 211     if (dependencies_size != 0) {
 212       tty->print_cr("   dependencies  = %u (%f%%)", dependencies_size, (dependencies_size * 100.0f)/total_immut_size);
 213     }
 214     if (nul_chk_table_size != 0) {
 215       tty->print_cr("   nul chk table = %u (%f%%)", nul_chk_table_size, (nul_chk_table_size * 100.0f)/total_immut_size);
 216     }
 217     if (handler_table_size != 0) {
 218       tty->print_cr("   handler table = %u (%f%%)", handler_table_size, (handler_table_size * 100.0f)/total_immut_size);
 219     }
 220     if (scopes_pcs_size != 0) {
 221       tty->print_cr("   scopes pcs    = %u (%f%%)", scopes_pcs_size, (scopes_pcs_size * 100.0f)/total_immut_size);
 222     }
 223     if (scopes_data_size != 0) {
 224       tty->print_cr("   scopes data   = %u (%f%%)", scopes_data_size, (scopes_data_size * 100.0f)/total_immut_size);
 225     }
 226 #if INCLUDE_JVMCI
 227     if (speculations_size != 0) {
 228       tty->print_cr("   speculations  = %u (%f%%)", speculations_size, (speculations_size * 100.0f)/total_immut_size);
 229     }
 230 #endif
 231   }
 232 };
 233 
 234 struct native_nmethod_stats_struct {
 235   uint native_nmethod_count;
 236   uint native_total_size;
 237   uint native_relocation_size;
 238   uint native_insts_size;
 239   uint native_oops_size;
 240   uint native_metadata_size;
 241   void note_native_nmethod(nmethod* nm) {
 242     native_nmethod_count += 1;
 243     native_total_size       += nm->size();
 244     native_relocation_size  += nm->relocation_size();
 245     native_insts_size       += nm->insts_size();
 246     native_oops_size        += nm->oops_size();
 247     native_metadata_size    += nm->metadata_size();
 248   }
 249   void print_native_nmethod_stats() {
 250     if (native_nmethod_count == 0)  return;
 251     tty->print_cr("Statistics for %u native nmethods:", native_nmethod_count);
 252     if (native_total_size != 0)       tty->print_cr(" N. total size  = %u", native_total_size);
 253     if (native_relocation_size != 0)  tty->print_cr(" N. relocation  = %u", native_relocation_size);
 254     if (native_insts_size != 0)       tty->print_cr(" N. main code   = %u", native_insts_size);
 255     if (native_oops_size != 0)        tty->print_cr(" N. oops        = %u", native_oops_size);
 256     if (native_metadata_size != 0)    tty->print_cr(" N. metadata    = %u", native_metadata_size);
 257   }
 258 };
 259 
 260 struct pc_nmethod_stats_struct {
 261   uint pc_desc_init;     // number of initialization of cache (= number of caches)
 262   uint pc_desc_queries;  // queries to nmethod::find_pc_desc
 263   uint pc_desc_approx;   // number of those which have approximate true
 264   uint pc_desc_repeats;  // number of _pc_descs[0] hits
 265   uint pc_desc_hits;     // number of LRU cache hits
 266   uint pc_desc_tests;    // total number of PcDesc examinations
 267   uint pc_desc_searches; // total number of quasi-binary search steps
 268   uint pc_desc_adds;     // number of LUR cache insertions
 269 
 270   void print_pc_stats() {
 271     tty->print_cr("PcDesc Statistics:  %u queries, %.2f comparisons per query",
 272                   pc_desc_queries,
 273                   (double)(pc_desc_tests + pc_desc_searches)
 274                   / pc_desc_queries);
 275     tty->print_cr("  caches=%d queries=%u/%u, hits=%u+%u, tests=%u+%u, adds=%u",
 276                   pc_desc_init,
 277                   pc_desc_queries, pc_desc_approx,
 278                   pc_desc_repeats, pc_desc_hits,
 279                   pc_desc_tests, pc_desc_searches, pc_desc_adds);
 280   }
 281 };
 282 
 283 #ifdef COMPILER1
 284 static java_nmethod_stats_struct c1_java_nmethod_stats;
 285 #endif
 286 #ifdef COMPILER2
 287 static java_nmethod_stats_struct c2_java_nmethod_stats;
 288 #endif
 289 #if INCLUDE_JVMCI
 290 static java_nmethod_stats_struct jvmci_java_nmethod_stats;
 291 #endif
 292 static java_nmethod_stats_struct unknown_java_nmethod_stats;
 293 
 294 static native_nmethod_stats_struct native_nmethod_stats;
 295 static pc_nmethod_stats_struct pc_nmethod_stats;
 296 
 297 static void note_java_nmethod(nmethod* nm) {
 298 #ifdef COMPILER1
 299   if (nm->is_compiled_by_c1()) {
 300     c1_java_nmethod_stats.note_nmethod(nm);
 301   } else
 302 #endif
 303 #ifdef COMPILER2
 304   if (nm->is_compiled_by_c2()) {
 305     c2_java_nmethod_stats.note_nmethod(nm);
 306   } else
 307 #endif
 308 #if INCLUDE_JVMCI
 309   if (nm->is_compiled_by_jvmci()) {
 310     jvmci_java_nmethod_stats.note_nmethod(nm);
 311   } else
 312 #endif
 313   {
 314     unknown_java_nmethod_stats.note_nmethod(nm);
 315   }
 316 }
 317 #endif // !PRODUCT
 318 
 319 //---------------------------------------------------------------------------------
 320 
 321 
 322 ExceptionCache::ExceptionCache(Handle exception, address pc, address handler) {
 323   assert(pc != nullptr, "Must be non null");
 324   assert(exception.not_null(), "Must be non null");
 325   assert(handler != nullptr, "Must be non null");
 326 
 327   _count = 0;
 328   _exception_type = exception->klass();
 329   _next = nullptr;
 330   _purge_list_next = nullptr;
 331 
 332   add_address_and_handler(pc,handler);
 333 }
 334 
 335 
 336 address ExceptionCache::match(Handle exception, address pc) {
 337   assert(pc != nullptr,"Must be non null");
 338   assert(exception.not_null(),"Must be non null");
 339   if (exception->klass() == exception_type()) {
 340     return (test_address(pc));
 341   }
 342 
 343   return nullptr;
 344 }
 345 
 346 
 347 bool ExceptionCache::match_exception_with_space(Handle exception) {
 348   assert(exception.not_null(),"Must be non null");
 349   if (exception->klass() == exception_type() && count() < cache_size) {
 350     return true;
 351   }
 352   return false;
 353 }
 354 
 355 
 356 address ExceptionCache::test_address(address addr) {
 357   int limit = count();
 358   for (int i = 0; i < limit; i++) {
 359     if (pc_at(i) == addr) {
 360       return handler_at(i);
 361     }
 362   }
 363   return nullptr;
 364 }
 365 
 366 
 367 bool ExceptionCache::add_address_and_handler(address addr, address handler) {
 368   if (test_address(addr) == handler) return true;
 369 
 370   int index = count();
 371   if (index < cache_size) {
 372     set_pc_at(index, addr);
 373     set_handler_at(index, handler);
 374     increment_count();
 375     return true;
 376   }
 377   return false;
 378 }
 379 
 380 ExceptionCache* ExceptionCache::next() {
 381   return AtomicAccess::load(&_next);
 382 }
 383 
 384 void ExceptionCache::set_next(ExceptionCache *ec) {
 385   AtomicAccess::store(&_next, ec);
 386 }
 387 
 388 //-----------------------------------------------------------------------------
 389 
 390 
 391 // Helper used by both find_pc_desc methods.
 392 static inline bool match_desc(PcDesc* pc, int pc_offset, bool approximate) {
 393   NOT_PRODUCT(++pc_nmethod_stats.pc_desc_tests);
 394   if (!approximate) {
 395     return pc->pc_offset() == pc_offset;
 396   } else {
 397     // Do not look before the sentinel
 398     assert(pc_offset > PcDesc::lower_offset_limit, "illegal pc_offset");
 399     return pc_offset <= pc->pc_offset() && (pc-1)->pc_offset() < pc_offset;
 400   }
 401 }
 402 
 403 void PcDescCache::init_to(PcDesc* initial_pc_desc) {
 404   NOT_PRODUCT(++pc_nmethod_stats.pc_desc_init);
 405   // initialize the cache by filling it with benign (non-null) values
 406   assert(initial_pc_desc != nullptr && initial_pc_desc->pc_offset() == PcDesc::lower_offset_limit,
 407          "must start with a sentinel");
 408   for (int i = 0; i < cache_size; i++) {
 409     _pc_descs[i] = initial_pc_desc;
 410   }
 411 }
 412 
 413 PcDesc* PcDescCache::find_pc_desc(int pc_offset, bool approximate) {
 414   // Note: one might think that caching the most recently
 415   // read value separately would be a win, but one would be
 416   // wrong.  When many threads are updating it, the cache
 417   // line it's in would bounce between caches, negating
 418   // any benefit.
 419 
 420   // In order to prevent race conditions do not load cache elements
 421   // repeatedly, but use a local copy:
 422   PcDesc* res;
 423 
 424   // Step one:  Check the most recently added value.
 425   res = _pc_descs[0];
 426   assert(res != nullptr, "PcDesc cache should be initialized already");
 427 
 428   // Approximate only here since PcDescContainer::find_pc_desc() checked for exact case.
 429   if (approximate && match_desc(res, pc_offset, approximate)) {
 430     NOT_PRODUCT(++pc_nmethod_stats.pc_desc_repeats);
 431     return res;
 432   }
 433 
 434   // Step two:  Check the rest of the LRU cache.
 435   for (int i = 1; i < cache_size; ++i) {
 436     res = _pc_descs[i];
 437     if (res->pc_offset() < 0) break;  // optimization: skip empty cache
 438     if (match_desc(res, pc_offset, approximate)) {
 439       NOT_PRODUCT(++pc_nmethod_stats.pc_desc_hits);
 440       return res;
 441     }
 442   }
 443 
 444   // Report failure.
 445   return nullptr;
 446 }
 447 
 448 void PcDescCache::add_pc_desc(PcDesc* pc_desc) {
 449   NOT_PRODUCT(++pc_nmethod_stats.pc_desc_adds);
 450   // Update the LRU cache by shifting pc_desc forward.
 451   for (int i = 0; i < cache_size; i++)  {
 452     PcDesc* next = _pc_descs[i];
 453     _pc_descs[i] = pc_desc;
 454     pc_desc = next;
 455   }
 456 }
 457 
 458 // adjust pcs_size so that it is a multiple of both oopSize and
 459 // sizeof(PcDesc) (assumes that if sizeof(PcDesc) is not a multiple
 460 // of oopSize, then 2*sizeof(PcDesc) is)
 461 static int adjust_pcs_size(int pcs_size) {
 462   int nsize = align_up(pcs_size,   oopSize);
 463   if ((nsize % sizeof(PcDesc)) != 0) {
 464     nsize = pcs_size + sizeof(PcDesc);
 465   }
 466   assert((nsize % oopSize) == 0, "correct alignment");
 467   return nsize;
 468 }
 469 
 470 // Returns a string version of the method state.
 471 const char* nmethod::state() const {
 472   int state = get_state();
 473   switch (state) {
 474   case not_installed:
 475     return "not installed";
 476   case in_use:
 477     return "in use";
 478   case not_entrant:
 479     return "not_entrant";
 480   default:
 481     fatal("unexpected method state: %d", state);
 482     return nullptr;
 483   }
 484 }
 485 
 486 void nmethod::set_deoptimized_done() {
 487   ConditionalMutexLocker ml(NMethodState_lock, !NMethodState_lock->owned_by_self(), Mutex::_no_safepoint_check_flag);
 488   if (_deoptimization_status != deoptimize_done) { // can't go backwards
 489     AtomicAccess::store(&_deoptimization_status, deoptimize_done);
 490   }
 491 }
 492 
 493 ExceptionCache* nmethod::exception_cache_acquire() const {
 494   return AtomicAccess::load_acquire(&_exception_cache);
 495 }
 496 
 497 void nmethod::add_exception_cache_entry(ExceptionCache* new_entry) {
 498   assert(ExceptionCache_lock->owned_by_self(),"Must hold the ExceptionCache_lock");
 499   assert(new_entry != nullptr,"Must be non null");
 500   assert(new_entry->next() == nullptr, "Must be null");
 501 
 502   for (;;) {
 503     ExceptionCache *ec = exception_cache();
 504     if (ec != nullptr) {
 505       Klass* ex_klass = ec->exception_type();
 506       if (!ex_klass->is_loader_alive()) {
 507         // We must guarantee that entries are not inserted with new next pointer
 508         // edges to ExceptionCache entries with dead klasses, due to bad interactions
 509         // with concurrent ExceptionCache cleanup. Therefore, the inserts roll
 510         // the head pointer forward to the first live ExceptionCache, so that the new
 511         // next pointers always point at live ExceptionCaches, that are not removed due
 512         // to concurrent ExceptionCache cleanup.
 513         ExceptionCache* next = ec->next();
 514         if (AtomicAccess::cmpxchg(&_exception_cache, ec, next) == ec) {
 515           CodeCache::release_exception_cache(ec);
 516         }
 517         continue;
 518       }
 519       ec = exception_cache();
 520       if (ec != nullptr) {
 521         new_entry->set_next(ec);
 522       }
 523     }
 524     if (AtomicAccess::cmpxchg(&_exception_cache, ec, new_entry) == ec) {
 525       return;
 526     }
 527   }
 528 }
 529 
 530 void nmethod::clean_exception_cache() {
 531   // For each nmethod, only a single thread may call this cleanup function
 532   // at the same time, whether called in STW cleanup or concurrent cleanup.
 533   // Note that if the GC is processing exception cache cleaning in a concurrent phase,
 534   // then a single writer may contend with cleaning up the head pointer to the
 535   // first ExceptionCache node that has a Klass* that is alive. That is fine,
 536   // as long as there is no concurrent cleanup of next pointers from concurrent writers.
 537   // And the concurrent writers do not clean up next pointers, only the head.
 538   // Also note that concurrent readers will walk through Klass* pointers that are not
 539   // alive. That does not cause ABA problems, because Klass* is deleted after
 540   // a handshake with all threads, after all stale ExceptionCaches have been
 541   // unlinked. That is also when the CodeCache::exception_cache_purge_list()
 542   // is deleted, with all ExceptionCache entries that were cleaned concurrently.
 543   // That similarly implies that CAS operations on ExceptionCache entries do not
 544   // suffer from ABA problems as unlinking and deletion is separated by a global
 545   // handshake operation.
 546   ExceptionCache* prev = nullptr;
 547   ExceptionCache* curr = exception_cache_acquire();
 548 
 549   while (curr != nullptr) {
 550     ExceptionCache* next = curr->next();
 551 
 552     if (!curr->exception_type()->is_loader_alive()) {
 553       if (prev == nullptr) {
 554         // Try to clean head; this is contended by concurrent inserts, that
 555         // both lazily clean the head, and insert entries at the head. If
 556         // the CAS fails, the operation is restarted.
 557         if (AtomicAccess::cmpxchg(&_exception_cache, curr, next) != curr) {
 558           prev = nullptr;
 559           curr = exception_cache_acquire();
 560           continue;
 561         }
 562       } else {
 563         // It is impossible to during cleanup connect the next pointer to
 564         // an ExceptionCache that has not been published before a safepoint
 565         // prior to the cleanup. Therefore, release is not required.
 566         prev->set_next(next);
 567       }
 568       // prev stays the same.
 569 
 570       CodeCache::release_exception_cache(curr);
 571     } else {
 572       prev = curr;
 573     }
 574 
 575     curr = next;
 576   }
 577 }
 578 
 579 // public method for accessing the exception cache
 580 // These are the public access methods.
 581 address nmethod::handler_for_exception_and_pc(Handle exception, address pc) {
 582   // We never grab a lock to read the exception cache, so we may
 583   // have false negatives. This is okay, as it can only happen during
 584   // the first few exception lookups for a given nmethod.
 585   ExceptionCache* ec = exception_cache_acquire();
 586   while (ec != nullptr) {
 587     address ret_val;
 588     if ((ret_val = ec->match(exception,pc)) != nullptr) {
 589       return ret_val;
 590     }
 591     ec = ec->next();
 592   }
 593   return nullptr;
 594 }
 595 
 596 void nmethod::add_handler_for_exception_and_pc(Handle exception, address pc, address handler) {
 597   // There are potential race conditions during exception cache updates, so we
 598   // must own the ExceptionCache_lock before doing ANY modifications. Because
 599   // we don't lock during reads, it is possible to have several threads attempt
 600   // to update the cache with the same data. We need to check for already inserted
 601   // copies of the current data before adding it.
 602 
 603   MutexLocker ml(ExceptionCache_lock);
 604   ExceptionCache* target_entry = exception_cache_entry_for_exception(exception);
 605 
 606   if (target_entry == nullptr || !target_entry->add_address_and_handler(pc,handler)) {
 607     target_entry = new ExceptionCache(exception,pc,handler);
 608     add_exception_cache_entry(target_entry);
 609   }
 610 }
 611 
 612 // private method for handling exception cache
 613 // These methods are private, and used to manipulate the exception cache
 614 // directly.
 615 ExceptionCache* nmethod::exception_cache_entry_for_exception(Handle exception) {
 616   ExceptionCache* ec = exception_cache_acquire();
 617   while (ec != nullptr) {
 618     if (ec->match_exception_with_space(exception)) {
 619       return ec;
 620     }
 621     ec = ec->next();
 622   }
 623   return nullptr;
 624 }
 625 
 626 bool nmethod::is_at_poll_return(address pc) {
 627   RelocIterator iter(this, pc, pc+1);
 628   while (iter.next()) {
 629     if (iter.type() == relocInfo::poll_return_type)
 630       return true;
 631   }
 632   return false;
 633 }
 634 
 635 
 636 bool nmethod::is_at_poll_or_poll_return(address pc) {
 637   RelocIterator iter(this, pc, pc+1);
 638   while (iter.next()) {
 639     relocInfo::relocType t = iter.type();
 640     if (t == relocInfo::poll_return_type || t == relocInfo::poll_type)
 641       return true;
 642   }
 643   return false;
 644 }
 645 
 646 void nmethod::verify_oop_relocations() {
 647   // Ensure sure that the code matches the current oop values
 648   RelocIterator iter(this, nullptr, nullptr);
 649   while (iter.next()) {
 650     if (iter.type() == relocInfo::oop_type) {
 651       oop_Relocation* reloc = iter.oop_reloc();
 652       if (!reloc->oop_is_immediate()) {
 653         reloc->verify_oop_relocation();
 654       }
 655     }
 656   }
 657 }
 658 
 659 
 660 ScopeDesc* nmethod::scope_desc_at(address pc) {
 661   PcDesc* pd = pc_desc_at(pc);
 662   guarantee(pd != nullptr, "scope must be present");
 663   return new ScopeDesc(this, pd);
 664 }
 665 
 666 ScopeDesc* nmethod::scope_desc_near(address pc) {
 667   PcDesc* pd = pc_desc_near(pc);
 668   guarantee(pd != nullptr, "scope must be present");
 669   return new ScopeDesc(this, pd);
 670 }
 671 
 672 address nmethod::oops_reloc_begin() const {
 673   // If the method is not entrant then a JMP is plastered over the
 674   // first few bytes.  If an oop in the old code was there, that oop
 675   // should not get GC'd.  Skip the first few bytes of oops on
 676   // not-entrant methods.
 677   if (frame_complete_offset() != CodeOffsets::frame_never_safe &&
 678       code_begin() + frame_complete_offset() >
 679       verified_entry_point() + NativeJump::instruction_size)
 680   {
 681     // If we have a frame_complete_offset after the native jump, then there
 682     // is no point trying to look for oops before that. This is a requirement
 683     // for being allowed to scan oops concurrently.
 684     return code_begin() + frame_complete_offset();
 685   }
 686 
 687   address low_boundary = verified_entry_point();
 688   return low_boundary;
 689 }
 690 
 691 // Method that knows how to preserve outgoing arguments at call. This method must be
 692 // called with a frame corresponding to a Java invoke
 693 void nmethod::preserve_callee_argument_oops(frame fr, const RegisterMap *reg_map, OopClosure* f) {
 694   if (method() == nullptr) {
 695     return;
 696   }
 697 
 698   // handle the case of an anchor explicitly set in continuation code that doesn't have a callee
 699   JavaThread* thread = reg_map->thread();
 700   if ((thread->has_last_Java_frame() && fr.sp() == thread->last_Java_sp())
 701       JVMTI_ONLY(|| (method()->is_continuation_enter_intrinsic() && thread->on_monitor_waited_event()))) {
 702     return;
 703   }
 704 
 705   if (!method()->is_native()) {
 706     address pc = fr.pc();
 707     bool has_receiver, has_appendix;
 708     Symbol* signature;
 709 
 710     // The method attached by JIT-compilers should be used, if present.
 711     // Bytecode can be inaccurate in such case.
 712     Method* callee = attached_method_before_pc(pc);
 713     if (callee != nullptr) {
 714       has_receiver = !(callee->access_flags().is_static());
 715       has_appendix = false;
 716       signature    = callee->signature();
 717     } else {
 718       SimpleScopeDesc ssd(this, pc);
 719 
 720       Bytecode_invoke call(methodHandle(Thread::current(), ssd.method()), ssd.bci());
 721       has_receiver = call.has_receiver();
 722       has_appendix = call.has_appendix();
 723       signature    = call.signature();
 724     }
 725 
 726     fr.oops_compiled_arguments_do(signature, has_receiver, has_appendix, reg_map, f);
 727   } else if (method()->is_continuation_enter_intrinsic()) {
 728     // This method only calls Continuation.enter()
 729     Symbol* signature = vmSymbols::continuationEnter_signature();
 730     fr.oops_compiled_arguments_do(signature, false, false, reg_map, f);
 731   }
 732 }
 733 
 734 Method* nmethod::attached_method(address call_instr) {
 735   assert(code_contains(call_instr), "not part of the nmethod");
 736   RelocIterator iter(this, call_instr, call_instr + 1);
 737   while (iter.next()) {
 738     if (iter.addr() == call_instr) {
 739       switch(iter.type()) {
 740         case relocInfo::static_call_type:      return iter.static_call_reloc()->method_value();
 741         case relocInfo::opt_virtual_call_type: return iter.opt_virtual_call_reloc()->method_value();
 742         case relocInfo::virtual_call_type:     return iter.virtual_call_reloc()->method_value();
 743         default:                               break;
 744       }
 745     }
 746   }
 747   return nullptr; // not found
 748 }
 749 
 750 Method* nmethod::attached_method_before_pc(address pc) {
 751   if (NativeCall::is_call_before(pc)) {
 752     NativeCall* ncall = nativeCall_before(pc);
 753     return attached_method(ncall->instruction_address());
 754   }
 755   return nullptr; // not a call
 756 }
 757 
 758 void nmethod::clear_inline_caches() {
 759   assert(SafepointSynchronize::is_at_safepoint() || (NMethodState_lock->owned_by_self() && is_not_installed()), "clearing of IC's only allowed at safepoint or when not installed");
 760   RelocIterator iter(this);
 761   while (iter.next()) {
 762     iter.reloc()->clear_inline_cache();
 763   }
 764 }
 765 
 766 #ifdef ASSERT
 767 // Check class_loader is alive for this bit of metadata.
 768 class CheckClass : public MetadataClosure {
 769   void do_metadata(Metadata* md) {
 770     Klass* klass = nullptr;
 771     if (md->is_klass()) {
 772       klass = ((Klass*)md);
 773     } else if (md->is_method()) {
 774       klass = ((Method*)md)->method_holder();
 775     } else if (md->is_methodData()) {
 776       klass = ((MethodData*)md)->method()->method_holder();
 777     } else if (md->is_methodCounters()) {
 778       klass = ((MethodCounters*)md)->method()->method_holder();
 779     } else {
 780       md->print();
 781       ShouldNotReachHere();
 782     }
 783     assert(klass->is_loader_alive(), "must be alive");
 784   }
 785 };
 786 #endif // ASSERT
 787 
 788 // Clean references to unloaded nmethods at addr from this one, which is not unloaded.
 789 template <typename CallsiteT>
 790 static void clean_if_nmethod_is_unloaded(CallsiteT* callsite, bool clean_all) {
 791   CodeBlob* cb = CodeCache::find_blob(callsite->destination());
 792   if (!cb->is_nmethod()) {
 793     return;
 794   }
 795   nmethod* nm = cb->as_nmethod();
 796   if (clean_all || !nm->is_in_use() || nm->is_unloading() || nm->method()->code() != nm) {
 797     callsite->set_to_clean();
 798   }
 799 }
 800 
 801 // Cleans caches in nmethods that point to either classes that are unloaded
 802 // or nmethods that are unloaded.
 803 //
 804 // Can be called either in parallel by G1 currently or after all
 805 // nmethods are unloaded.  Return postponed=true in the parallel case for
 806 // inline caches found that point to nmethods that are not yet visited during
 807 // the do_unloading walk.
 808 void nmethod::unload_nmethod_caches(bool unloading_occurred) {
 809   ResourceMark rm;
 810 
 811   // Exception cache only needs to be called if unloading occurred
 812   if (unloading_occurred) {
 813     clean_exception_cache();
 814   }
 815 
 816   cleanup_inline_caches_impl(unloading_occurred, false);
 817 
 818 #ifdef ASSERT
 819   // Check that the metadata embedded in the nmethod is alive
 820   CheckClass check_class;
 821   metadata_do(&check_class);
 822 #endif
 823 }
 824 
 825 void nmethod::run_nmethod_entry_barrier() {
 826   BarrierSetNMethod* bs_nm = BarrierSet::barrier_set()->barrier_set_nmethod();
 827   if (bs_nm != nullptr) {
 828     // We want to keep an invariant that nmethods found through iterations of a Thread's
 829     // nmethods found in safepoints have gone through an entry barrier and are not armed.
 830     // By calling this nmethod entry barrier, it plays along and acts
 831     // like any other nmethod found on the stack of a thread (fewer surprises).
 832     nmethod* nm = this;
 833     bool alive = bs_nm->nmethod_entry_barrier(nm);
 834     assert(alive, "should be alive");
 835   }
 836 }
 837 
 838 // Only called by whitebox test
 839 void nmethod::cleanup_inline_caches_whitebox() {
 840   assert_locked_or_safepoint(CodeCache_lock);
 841   CompiledICLocker ic_locker(this);
 842   cleanup_inline_caches_impl(false /* unloading_occurred */, true /* clean_all */);
 843 }
 844 
 845 address* nmethod::orig_pc_addr(const frame* fr) {
 846   return (address*) ((address)fr->unextended_sp() + orig_pc_offset());
 847 }
 848 
 849 // Called to clean up after class unloading for live nmethods
 850 void nmethod::cleanup_inline_caches_impl(bool unloading_occurred, bool clean_all) {
 851   assert(CompiledICLocker::is_safe(this), "mt unsafe call");
 852   ResourceMark rm;
 853 
 854   // Find all calls in an nmethod and clear the ones that point to bad nmethods.
 855   RelocIterator iter(this, oops_reloc_begin());
 856   bool is_in_static_stub = false;
 857   while(iter.next()) {
 858 
 859     switch (iter.type()) {
 860 
 861     case relocInfo::virtual_call_type:
 862       if (unloading_occurred) {
 863         // If class unloading occurred we first clear ICs where the cached metadata
 864         // is referring to an unloaded klass or method.
 865         CompiledIC_at(&iter)->clean_metadata();
 866       }
 867 
 868       clean_if_nmethod_is_unloaded(CompiledIC_at(&iter), clean_all);
 869       break;
 870 
 871     case relocInfo::opt_virtual_call_type:
 872     case relocInfo::static_call_type:
 873       clean_if_nmethod_is_unloaded(CompiledDirectCall::at(iter.reloc()), clean_all);
 874       break;
 875 
 876     case relocInfo::static_stub_type: {
 877       is_in_static_stub = true;
 878       break;
 879     }
 880 
 881     case relocInfo::metadata_type: {
 882       // Only the metadata relocations contained in static/opt virtual call stubs
 883       // contains the Method* passed to c2i adapters. It is the only metadata
 884       // relocation that needs to be walked, as it is the one metadata relocation
 885       // that violates the invariant that all metadata relocations have an oop
 886       // in the compiled method (due to deferred resolution and code patching).
 887 
 888       // This causes dead metadata to remain in compiled methods that are not
 889       // unloading. Unless these slippery metadata relocations of the static
 890       // stubs are at least cleared, subsequent class redefinition operations
 891       // will access potentially free memory, and JavaThread execution
 892       // concurrent to class unloading may call c2i adapters with dead methods.
 893       if (!is_in_static_stub) {
 894         // The first metadata relocation after a static stub relocation is the
 895         // metadata relocation of the static stub used to pass the Method* to
 896         // c2i adapters.
 897         continue;
 898       }
 899       is_in_static_stub = false;
 900       if (is_unloading()) {
 901         // If the nmethod itself is dying, then it may point at dead metadata.
 902         // Nobody should follow that metadata; it is strictly unsafe.
 903         continue;
 904       }
 905       metadata_Relocation* r = iter.metadata_reloc();
 906       Metadata* md = r->metadata_value();
 907       if (md != nullptr && md->is_method()) {
 908         Method* method = static_cast<Method*>(md);
 909         if (!method->method_holder()->is_loader_alive()) {
 910           AtomicAccess::store(r->metadata_addr(), (Method*)nullptr);
 911 
 912           if (!r->metadata_is_immediate()) {
 913             r->fix_metadata_relocation();
 914           }
 915         }
 916       }
 917       break;
 918     }
 919 
 920     default:
 921       break;
 922     }
 923   }
 924 }
 925 
 926 address nmethod::continuation_for_implicit_exception(address pc, bool for_div0_check) {
 927   // Exception happened outside inline-cache check code => we are inside
 928   // an active nmethod => use cpc to determine a return address
 929   int exception_offset = int(pc - code_begin());
 930   int cont_offset = ImplicitExceptionTable(this).continuation_offset( exception_offset );
 931 #ifdef ASSERT
 932   if (cont_offset == 0) {
 933     Thread* thread = Thread::current();
 934     ResourceMark rm(thread);
 935     CodeBlob* cb = CodeCache::find_blob(pc);
 936     assert(cb != nullptr && cb == this, "");
 937 
 938     // Keep tty output consistent. To avoid ttyLocker, we buffer in stream, and print all at once.
 939     stringStream ss;
 940     ss.print_cr("implicit exception happened at " INTPTR_FORMAT, p2i(pc));
 941     print_on(&ss);
 942     // Buffering to a stringStream, disable internal buffering so it's not done twice.
 943     method()->print_codes_on(&ss, 0, false);
 944     print_code_on(&ss);
 945     print_pcs_on(&ss);
 946     tty->print("%s", ss.as_string()); // print all at once
 947   }
 948 #endif
 949   if (cont_offset == 0) {
 950     // Let the normal error handling report the exception
 951     return nullptr;
 952   }
 953   if (cont_offset == exception_offset) {
 954 #if INCLUDE_JVMCI
 955     Deoptimization::DeoptReason deopt_reason = for_div0_check ? Deoptimization::Reason_div0_check : Deoptimization::Reason_null_check;
 956     JavaThread *thread = JavaThread::current();
 957     thread->set_jvmci_implicit_exception_pc(pc);
 958     thread->set_pending_deoptimization(Deoptimization::make_trap_request(deopt_reason,
 959                                                                          Deoptimization::Action_reinterpret));
 960     return (SharedRuntime::deopt_blob()->implicit_exception_uncommon_trap());
 961 #else
 962     ShouldNotReachHere();
 963 #endif
 964   }
 965   return code_begin() + cont_offset;
 966 }
 967 
 968 class HasEvolDependency : public MetadataClosure {
 969   bool _has_evol_dependency;
 970  public:
 971   HasEvolDependency() : _has_evol_dependency(false) {}
 972   void do_metadata(Metadata* md) {
 973     if (md->is_method()) {
 974       Method* method = (Method*)md;
 975       if (method->is_old()) {
 976         _has_evol_dependency = true;
 977       }
 978     }
 979   }
 980   bool has_evol_dependency() const { return _has_evol_dependency; }
 981 };
 982 
 983 bool nmethod::has_evol_metadata() {
 984   // Check the metadata in relocIter and CompiledIC and also deoptimize
 985   // any nmethod that has reference to old methods.
 986   HasEvolDependency check_evol;
 987   metadata_do(&check_evol);
 988   if (check_evol.has_evol_dependency() && log_is_enabled(Debug, redefine, class, nmethod)) {
 989     ResourceMark rm;
 990     log_debug(redefine, class, nmethod)
 991             ("Found evol dependency of nmethod %s.%s(%s) compile_id=%d on in nmethod metadata",
 992              _method->method_holder()->external_name(),
 993              _method->name()->as_C_string(),
 994              _method->signature()->as_C_string(),
 995              compile_id());
 996   }
 997   return check_evol.has_evol_dependency();
 998 }
 999 
1000 int nmethod::total_size() const {
1001   return
1002     consts_size()        +
1003     insts_size()         +
1004     stub_size()          +
1005     scopes_data_size()   +
1006     scopes_pcs_size()    +
1007     handler_table_size() +
1008     nul_chk_table_size();
1009 }
1010 
1011 const char* nmethod::compile_kind() const {
1012   if (is_osr_method())     return "osr";
1013   if (method() != nullptr && is_native_method()) {
1014     if (method()->is_continuation_native_intrinsic()) {
1015       return "cnt";
1016     }
1017     return "c2n";
1018   }
1019   return nullptr;
1020 }
1021 
1022 const char* nmethod::compiler_name() const {
1023   return compilertype2name(_compiler_type);
1024 }
1025 
1026 #ifdef ASSERT
1027 class CheckForOopsClosure : public OopClosure {
1028   bool _found_oop = false;
1029  public:
1030   virtual void do_oop(oop* o) { _found_oop = true; }
1031   virtual void do_oop(narrowOop* o) { _found_oop = true; }
1032   bool found_oop() { return _found_oop; }
1033 };
1034 class CheckForMetadataClosure : public MetadataClosure {
1035   bool _found_metadata = false;
1036   Metadata* _ignore = nullptr;
1037  public:
1038   CheckForMetadataClosure(Metadata* ignore) : _ignore(ignore) {}
1039   virtual void do_metadata(Metadata* md) { if (md != _ignore) _found_metadata = true; }
1040   bool found_metadata() { return _found_metadata; }
1041 };
1042 
1043 static void assert_no_oops_or_metadata(nmethod* nm) {
1044   if (nm == nullptr) return;
1045   assert(nm->oop_maps() == nullptr, "expectation");
1046 
1047   CheckForOopsClosure cfo;
1048   nm->oops_do(&cfo);
1049   assert(!cfo.found_oop(), "no oops allowed");
1050 
1051   // We allow an exception for the own Method, but require its class to be permanent.
1052   Method* own_method = nm->method();
1053   CheckForMetadataClosure cfm(/* ignore reference to own Method */ own_method);
1054   nm->metadata_do(&cfm);
1055   assert(!cfm.found_metadata(), "no metadata allowed");
1056 
1057   assert(own_method->method_holder()->class_loader_data()->is_permanent_class_loader_data(),
1058          "Method's class needs to be permanent");
1059 }
1060 #endif
1061 
1062 static int required_mutable_data_size(CodeBuffer* code_buffer,
1063                                       int jvmci_data_size = 0) {
1064   return align_up(code_buffer->total_relocation_size(), oopSize) +
1065          align_up(code_buffer->total_metadata_size(), oopSize) +
1066          align_up(jvmci_data_size, oopSize);
1067 }
1068 
1069 nmethod* nmethod::new_native_nmethod(const methodHandle& method,
1070   int compile_id,
1071   CodeBuffer *code_buffer,
1072   int vep_offset,
1073   int frame_complete,
1074   int frame_size,
1075   ByteSize basic_lock_owner_sp_offset,
1076   ByteSize basic_lock_sp_offset,
1077   OopMapSet* oop_maps,
1078   int exception_handler) {
1079   code_buffer->finalize_oop_references(method);
1080   // create nmethod
1081   nmethod* nm = nullptr;
1082   int native_nmethod_size = CodeBlob::allocation_size(code_buffer, sizeof(nmethod));
1083   {
1084     MutexLocker mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
1085 
1086     CodeOffsets offsets;
1087     offsets.set_value(CodeOffsets::Verified_Entry, vep_offset);
1088     offsets.set_value(CodeOffsets::Frame_Complete, frame_complete);
1089     if (exception_handler != -1) {
1090       offsets.set_value(CodeOffsets::Exceptions, exception_handler);
1091     }
1092 
1093     int mutable_data_size = required_mutable_data_size(code_buffer);
1094 
1095     // MH intrinsics are dispatch stubs which are compatible with NonNMethod space.
1096     // IsUnloadingBehaviour::is_unloading needs to handle them separately.
1097     bool allow_NonNMethod_space = method->can_be_allocated_in_NonNMethod_space();
1098     nm = new (native_nmethod_size, allow_NonNMethod_space)
1099     nmethod(method(), compiler_none, native_nmethod_size,
1100             compile_id, &offsets,
1101             code_buffer, frame_size,
1102             basic_lock_owner_sp_offset,
1103             basic_lock_sp_offset,
1104             oop_maps, mutable_data_size);
1105     DEBUG_ONLY( if (allow_NonNMethod_space) assert_no_oops_or_metadata(nm); )
1106     NOT_PRODUCT(if (nm != nullptr) native_nmethod_stats.note_native_nmethod(nm));
1107   }
1108 
1109   if (nm != nullptr) {
1110     // verify nmethod
1111     DEBUG_ONLY(nm->verify();) // might block
1112 
1113     nm->log_new_nmethod();
1114   }
1115   return nm;
1116 }
1117 
1118 nmethod* nmethod::new_nmethod(const methodHandle& method,
1119   int compile_id,
1120   int entry_bci,
1121   CodeOffsets* offsets,
1122   int orig_pc_offset,
1123   DebugInformationRecorder* debug_info,
1124   Dependencies* dependencies,
1125   CodeBuffer* code_buffer, int frame_size,
1126   OopMapSet* oop_maps,
1127   ExceptionHandlerTable* handler_table,
1128   ImplicitExceptionTable* nul_chk_table,
1129   AbstractCompiler* compiler,
1130   CompLevel comp_level
1131 #if INCLUDE_JVMCI
1132   , char* speculations,
1133   int speculations_len,
1134   JVMCINMethodData* jvmci_data
1135 #endif
1136 )
1137 {
1138   assert(debug_info->oop_recorder() == code_buffer->oop_recorder(), "shared OR");
1139   code_buffer->finalize_oop_references(method);
1140   // create nmethod
1141   nmethod* nm = nullptr;
1142   int nmethod_size = CodeBlob::allocation_size(code_buffer, sizeof(nmethod));
1143 
1144   int immutable_data_size =
1145       adjust_pcs_size(debug_info->pcs_size())
1146     + align_up((int)dependencies->size_in_bytes(), oopSize)
1147     + align_up(handler_table->size_in_bytes()    , oopSize)
1148     + align_up(nul_chk_table->size_in_bytes()    , oopSize)
1149 #if INCLUDE_JVMCI
1150     + align_up(speculations_len                  , oopSize)
1151 #endif
1152     + align_up(debug_info->data_size()           , oopSize);
1153 
1154   // First, allocate space for immutable data in C heap.
1155   address immutable_data = nullptr;
1156   if (immutable_data_size > 0) {
1157     immutable_data_size += ImmutableDataRefCountSize;
1158     immutable_data = (address)os::malloc(immutable_data_size, mtCode);
1159     if (immutable_data == nullptr) {
1160       vm_exit_out_of_memory(immutable_data_size, OOM_MALLOC_ERROR, "nmethod: no space for immutable data");
1161       return nullptr;
1162     }
1163   }
1164 
1165   int mutable_data_size = required_mutable_data_size(code_buffer
1166     JVMCI_ONLY(COMMA (compiler->is_jvmci() ? jvmci_data->size() : 0)));
1167 
1168   {
1169     MutexLocker mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
1170 
1171     nm = new (nmethod_size, comp_level)
1172     nmethod(method(), compiler->type(), nmethod_size, immutable_data_size, mutable_data_size,
1173             compile_id, entry_bci, immutable_data, offsets, orig_pc_offset,
1174             debug_info, dependencies, code_buffer, frame_size, oop_maps,
1175             handler_table, nul_chk_table, compiler, comp_level
1176 #if INCLUDE_JVMCI
1177             , speculations,
1178             speculations_len,
1179             jvmci_data
1180 #endif
1181             );
1182 
1183     if (nm != nullptr) {
1184       // To make dependency checking during class loading fast, record
1185       // the nmethod dependencies in the classes it is dependent on.
1186       // This allows the dependency checking code to simply walk the
1187       // class hierarchy above the loaded class, checking only nmethods
1188       // which are dependent on those classes.  The slow way is to
1189       // check every nmethod for dependencies which makes it linear in
1190       // the number of methods compiled.  For applications with a lot
1191       // classes the slow way is too slow.
1192       for (Dependencies::DepStream deps(nm); deps.next(); ) {
1193         if (deps.type() == Dependencies::call_site_target_value) {
1194           // CallSite dependencies are managed on per-CallSite instance basis.
1195           oop call_site = deps.argument_oop(0);
1196           MethodHandles::add_dependent_nmethod(call_site, nm);
1197         } else {
1198           InstanceKlass* ik = deps.context_type();
1199           if (ik == nullptr) {
1200             continue;  // ignore things like evol_method
1201           }
1202           // record this nmethod as dependent on this klass
1203           ik->add_dependent_nmethod(nm);
1204         }
1205       }
1206       NOT_PRODUCT(if (nm != nullptr)  note_java_nmethod(nm));
1207     }
1208   }
1209   // Do verification and logging outside CodeCache_lock.
1210   if (nm != nullptr) {
1211     // Safepoints in nmethod::verify aren't allowed because nm hasn't been installed yet.
1212     DEBUG_ONLY(nm->verify();)
1213     nm->log_new_nmethod();
1214   }
1215   return nm;
1216 }
1217 
1218 // Fill in default values for various fields
1219 void nmethod::init_defaults(CodeBuffer *code_buffer, CodeOffsets* offsets) {
1220   // avoid uninitialized fields, even for short time periods
1221   _exception_cache            = nullptr;
1222   _gc_data                    = nullptr;
1223   _oops_do_mark_link          = nullptr;
1224   _compiled_ic_data           = nullptr;
1225 
1226   _is_unloading_state         = 0;
1227   _state                      = not_installed;
1228 
1229   _has_unsafe_access          = 0;
1230   _has_wide_vectors           = 0;
1231   _has_monitors               = 0;
1232   _has_scoped_access          = 0;
1233   _has_flushed_dependencies   = 0;
1234   _is_unlinked                = 0;
1235   _load_reported              = 0; // jvmti state
1236 
1237   _deoptimization_status      = not_marked;
1238 
1239   // SECT_CONSTS is first in code buffer so the offset should be 0.
1240   int consts_offset = code_buffer->total_offset_of(code_buffer->consts());
1241   assert(consts_offset == 0, "const_offset: %d", consts_offset);
1242 
1243   _stub_offset = content_offset() + code_buffer->total_offset_of(code_buffer->stubs());
1244 
1245   CHECKED_CAST(_entry_offset,              uint16_t, (offsets->value(CodeOffsets::Entry)));
1246   CHECKED_CAST(_verified_entry_offset,     uint16_t, (offsets->value(CodeOffsets::Verified_Entry)));
1247 
1248   _skipped_instructions_size = code_buffer->total_skipped_instructions_size();
1249 }
1250 
1251 // Post initialization
1252 void nmethod::post_init() {
1253   clear_unloading_state();
1254 
1255   finalize_relocations();
1256 
1257   // Flush generated code
1258   ICache::invalidate_range(code_begin(), code_size());
1259 
1260   Universe::heap()->register_nmethod(this);
1261   DEBUG_ONLY(Universe::heap()->verify_nmethod(this));
1262 
1263   CodeCache::commit(this);
1264 }
1265 
1266 // For native wrappers
1267 nmethod::nmethod(
1268   Method* method,
1269   CompilerType type,
1270   int nmethod_size,
1271   int compile_id,
1272   CodeOffsets* offsets,
1273   CodeBuffer* code_buffer,
1274   int frame_size,
1275   ByteSize basic_lock_owner_sp_offset,
1276   ByteSize basic_lock_sp_offset,
1277   OopMapSet* oop_maps,
1278   int mutable_data_size)
1279   : CodeBlob("native nmethod", CodeBlobKind::Nmethod, code_buffer, nmethod_size, sizeof(nmethod),
1280              offsets->value(CodeOffsets::Frame_Complete), frame_size, oop_maps, false, mutable_data_size),
1281   _deoptimization_generation(0),
1282   _gc_epoch(CodeCache::gc_epoch()),
1283   _method(method),
1284   _native_receiver_sp_offset(basic_lock_owner_sp_offset),
1285   _native_basic_lock_sp_offset(basic_lock_sp_offset)
1286 {
1287   {
1288     DEBUG_ONLY(NoSafepointVerifier nsv;)
1289     assert_locked_or_safepoint(CodeCache_lock);
1290 
1291     init_defaults(code_buffer, offsets);
1292 
1293     _osr_entry_point         = nullptr;
1294     _pc_desc_container       = nullptr;
1295     _entry_bci               = InvocationEntryBci;
1296     _compile_id              = compile_id;
1297     _comp_level              = CompLevel_none;
1298     _compiler_type           = type;
1299     _orig_pc_offset          = 0;
1300     _num_stack_arg_slots     = 0;
1301 
1302     if (offsets->value(CodeOffsets::Exceptions) != -1) {
1303       // Continuation enter intrinsic
1304       _exception_offset      = code_offset() + offsets->value(CodeOffsets::Exceptions);
1305     } else {
1306       _exception_offset      = 0;
1307     }
1308     // Native wrappers do not have deopt handlers. Make the values
1309     // something that will never match a pc like the nmethod vtable entry
1310     _deopt_handler_entry_offset    = 0;
1311     _unwind_handler_offset   = 0;
1312 
1313     int metadata_size = align_up(code_buffer->total_metadata_size(), wordSize);
1314     JVMCI_ONLY( _metadata_size = metadata_size; )
1315     assert(_mutable_data_size == _relocation_size + metadata_size,
1316            "wrong mutable data size: %d != %d + %d",
1317            _mutable_data_size, _relocation_size, metadata_size);
1318 
1319     // native wrapper does not have read-only data but we need unique not null address
1320     _immutable_data          = blob_end();
1321     _immutable_data_size     = 0;
1322     _nul_chk_table_offset    = 0;
1323     _handler_table_offset    = 0;
1324     _scopes_pcs_offset       = 0;
1325     _scopes_data_offset      = 0;
1326 #if INCLUDE_JVMCI
1327     _speculations_offset     = 0;
1328 #endif
1329     _immutable_data_ref_count_offset = 0;
1330 
1331     code_buffer->copy_code_and_locs_to(this);
1332     code_buffer->copy_values_to(this);
1333 
1334     post_init();
1335   }
1336 
1337   if (PrintNativeNMethods || PrintDebugInfo || PrintRelocations || PrintDependencies) {
1338     ttyLocker ttyl;  // keep the following output all in one block
1339     // This output goes directly to the tty, not the compiler log.
1340     // To enable tools to match it up with the compilation activity,
1341     // be sure to tag this tty output with the compile ID.
1342     if (xtty != nullptr) {
1343       xtty->begin_head("print_native_nmethod");
1344       xtty->method(_method);
1345       xtty->stamp();
1346       xtty->end_head(" address='" INTPTR_FORMAT "'", (intptr_t) this);
1347     }
1348     // Print the header part, then print the requested information.
1349     // This is both handled in decode2(), called via print_code() -> decode()
1350     if (PrintNativeNMethods) {
1351       tty->print_cr("-------------------------- Assembly (native nmethod) ---------------------------");
1352       print_code();
1353       tty->print_cr("- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ");
1354 #if defined(SUPPORT_DATA_STRUCTS)
1355       if (AbstractDisassembler::show_structs()) {
1356         if (oop_maps != nullptr) {
1357           tty->print("oop maps:"); // oop_maps->print_on(tty) outputs a cr() at the beginning
1358           oop_maps->print_on(tty);
1359           tty->print_cr("- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ");
1360         }
1361       }
1362 #endif
1363     } else {
1364       print(); // print the header part only.
1365     }
1366 #if defined(SUPPORT_DATA_STRUCTS)
1367     if (AbstractDisassembler::show_structs()) {
1368       if (PrintRelocations) {
1369         print_relocations();
1370         tty->print_cr("- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ");
1371       }
1372     }
1373 #endif
1374     if (xtty != nullptr) {
1375       xtty->tail("print_native_nmethod");
1376     }
1377   }
1378 }
1379 
1380 
1381 nmethod::nmethod(const nmethod &nm) : CodeBlob(nm._name, nm._kind, nm._size, nm._header_size)
1382 {
1383 
1384   if (nm._oop_maps != nullptr) {
1385     _oop_maps                   = nm._oop_maps->clone();
1386   } else {
1387     _oop_maps                   = nullptr;
1388   }
1389 
1390   _size                         = nm._size;
1391   _relocation_size              = nm._relocation_size;
1392   _content_offset               = nm._content_offset;
1393   _code_offset                  = nm._code_offset;
1394   _data_offset                  = nm._data_offset;
1395   _frame_size                   = nm._frame_size;
1396 
1397   S390_ONLY( _ctable_offset     = nm._ctable_offset; )
1398 
1399   _header_size                  = nm._header_size;
1400   _frame_complete_offset        = nm._frame_complete_offset;
1401 
1402   _kind                         = nm._kind;
1403 
1404   _caller_must_gc_arguments     = nm._caller_must_gc_arguments;
1405 
1406 #ifndef PRODUCT
1407   _asm_remarks.share(nm._asm_remarks);
1408   _dbg_strings.share(nm._dbg_strings);
1409 #endif
1410 
1411   // Allocate memory and copy mutable data to C heap
1412   _mutable_data_size            = nm._mutable_data_size;
1413   if (_mutable_data_size > 0) {
1414     _mutable_data = (address)os::malloc(_mutable_data_size, mtCode);
1415     if (_mutable_data == nullptr) {
1416       vm_exit_out_of_memory(_mutable_data_size, OOM_MALLOC_ERROR, "nmethod: no space for mutable data");
1417     }
1418     memcpy(mutable_data_begin(), nm.mutable_data_begin(), nm.mutable_data_size());
1419   } else {
1420     _mutable_data               = nullptr;
1421   }
1422 
1423   _deoptimization_generation    = 0;
1424   _gc_epoch                     = CodeCache::gc_epoch();
1425   _method                       = nm._method;
1426   _osr_link                     = nullptr;
1427 
1428   _exception_cache              = nullptr;
1429   _gc_data                      = nullptr;
1430   _oops_do_mark_nmethods        = nullptr;
1431   _oops_do_mark_link            = nullptr;
1432   _compiled_ic_data             = nullptr;
1433 
1434   if (nm._osr_entry_point != nullptr) {
1435     _osr_entry_point            = (nm._osr_entry_point - (address) &nm) + (address) this;
1436   } else {
1437     _osr_entry_point            = nullptr;
1438   }
1439 
1440   _entry_offset                 = nm._entry_offset;
1441   _verified_entry_offset        = nm._verified_entry_offset;
1442   _entry_bci                    = nm._entry_bci;
1443   _immutable_data_size          = nm._immutable_data_size;
1444 
1445   _skipped_instructions_size    = nm._skipped_instructions_size;
1446   _stub_offset                  = nm._stub_offset;
1447   _exception_offset             = nm._exception_offset;
1448   _deopt_handler_entry_offset   = nm._deopt_handler_entry_offset;
1449   _unwind_handler_offset        = nm._unwind_handler_offset;
1450   _num_stack_arg_slots          = nm._num_stack_arg_slots;
1451 #if INCLUDE_JVMCI
1452   _metadata_size                = nm._metadata_size;
1453 #endif
1454   _nul_chk_table_offset         = nm._nul_chk_table_offset;
1455   _handler_table_offset         = nm._handler_table_offset;
1456   _scopes_pcs_offset            = nm._scopes_pcs_offset;
1457   _scopes_data_offset           = nm._scopes_data_offset;
1458 #if INCLUDE_JVMCI
1459   _speculations_offset          = nm._speculations_offset;
1460 #endif
1461   _immutable_data_ref_count_offset = nm._immutable_data_ref_count_offset;
1462 
1463   // Increment number of references to immutable data to share it between nmethods
1464   if (_immutable_data_size > 0) {
1465     _immutable_data             = nm._immutable_data;
1466     inc_immutable_data_ref_count();
1467   } else {
1468     _immutable_data             = blob_end();
1469   }
1470 
1471   _orig_pc_offset               = nm._orig_pc_offset;
1472   _compile_id                   = nm._compile_id;
1473   _comp_level                   = nm._comp_level;
1474   _compiler_type                = nm._compiler_type;
1475   _is_unloading_state           = nm._is_unloading_state;
1476   _state                        = not_installed;
1477 
1478   _has_unsafe_access            = nm._has_unsafe_access;
1479   _has_wide_vectors             = nm._has_wide_vectors;
1480   _has_monitors                 = nm._has_monitors;
1481   _has_scoped_access            = nm._has_scoped_access;
1482   _has_flushed_dependencies     = nm._has_flushed_dependencies;
1483   _is_unlinked                  = nm._is_unlinked;
1484   _load_reported                = nm._load_reported;
1485 
1486   _deoptimization_status        = nm._deoptimization_status;
1487 
1488   if (nm._pc_desc_container != nullptr) {
1489     _pc_desc_container          = new PcDescContainer(scopes_pcs_begin());
1490   } else {
1491     _pc_desc_container          = nullptr;
1492   }
1493 
1494   // Copy nmethod contents excluding header
1495   // - Constant part          (doubles, longs and floats used in nmethod)
1496   // - Code part:
1497   //   - Code body
1498   //   - Exception handler
1499   //   - Stub code
1500   //   - OOP table
1501   memcpy(consts_begin(), nm.consts_begin(), nm.data_end() - nm.consts_begin());
1502 
1503   // Fix relocation
1504   RelocIterator iter(this);
1505   CodeBuffer src(&nm);
1506   CodeBuffer dst(this);
1507   while (iter.next()) {
1508 #ifdef USE_TRAMPOLINE_STUB_FIX_OWNER
1509     // After an nmethod is moved, some direct call sites may end up out of range.
1510     // CallRelocation::fix_relocation_after_move() assumes the target is always
1511     // reachable and does not check branch range. Calling it without range checks
1512     // could cause us to write an offset too large for the instruction.
1513     //
1514     // If a call site has a trampoline, we skip the normal call relocation. The
1515     // associated trampoline_stub_Relocation will handle the call and the
1516     // trampoline, including range checks and updating the branch as needed.
1517     //
1518     // If no trampoline exists, we can assume the call target is always
1519     // reachable and therefore within direct branch range, so calling
1520     // CallRelocation::fix_relocation_after_move() is safe.
1521     if (iter.reloc()->is_call()) {
1522       address trampoline = trampoline_stub_Relocation::get_trampoline_for(iter.reloc()->addr(), this);
1523       if (trampoline != nullptr) {
1524         continue;
1525       }
1526     }
1527 #endif
1528 
1529     iter.reloc()->fix_relocation_after_move(&src, &dst);
1530   }
1531 
1532   {
1533     MutexLocker ml(NMethodState_lock, Mutex::_no_safepoint_check_flag);
1534     clear_inline_caches();
1535   }
1536 
1537   post_init();
1538 }
1539 
1540 nmethod* nmethod::relocate(CodeBlobType code_blob_type) {
1541   assert(NMethodRelocation, "must enable use of function");
1542 
1543   // Locks required to be held by caller to ensure the nmethod
1544   // is not modified or purged from code cache during relocation
1545   assert_lock_strong(CodeCache_lock);
1546   assert_lock_strong(Compile_lock);
1547   assert(CompiledICLocker::is_safe(this), "mt unsafe call");
1548 
1549   if (!is_relocatable()) {
1550     return nullptr;
1551   }
1552 
1553   run_nmethod_entry_barrier();
1554   nmethod* nm_copy = new (size(), code_blob_type) nmethod(*this);
1555 
1556   if (nm_copy == nullptr) {
1557     return nullptr;
1558   }
1559 
1560   // To make dependency checking during class loading fast, record
1561   // the nmethod dependencies in the classes it is dependent on.
1562   // This allows the dependency checking code to simply walk the
1563   // class hierarchy above the loaded class, checking only nmethods
1564   // which are dependent on those classes.  The slow way is to
1565   // check every nmethod for dependencies which makes it linear in
1566   // the number of methods compiled.  For applications with a lot
1567   // classes the slow way is too slow.
1568   for (Dependencies::DepStream deps(nm_copy); deps.next(); ) {
1569     if (deps.type() == Dependencies::call_site_target_value) {
1570       // CallSite dependencies are managed on per-CallSite instance basis.
1571       oop call_site = deps.argument_oop(0);
1572       MethodHandles::add_dependent_nmethod(call_site, nm_copy);
1573     } else {
1574       InstanceKlass* ik = deps.context_type();
1575       if (ik == nullptr) {
1576         continue;  // ignore things like evol_method
1577       }
1578       // record this nmethod as dependent on this klass
1579       ik->add_dependent_nmethod(nm_copy);
1580     }
1581   }
1582 
1583   MutexLocker ml_NMethodState_lock(NMethodState_lock, Mutex::_no_safepoint_check_flag);
1584 
1585   // Verify the nm we copied from is still valid
1586   if (!is_marked_for_deoptimization() && is_in_use()) {
1587     assert(method() != nullptr && method()->code() == this, "should be if is in use");
1588 
1589     // Attempt to start using the copy
1590     if (nm_copy->make_in_use()) {
1591       methodHandle mh(Thread::current(), nm_copy->method());
1592       nm_copy->method()->set_code(mh, nm_copy);
1593 
1594       make_not_entrant(InvalidationReason::RELOCATED);
1595 
1596       nm_copy->post_compiled_method_load_event();
1597 
1598       nm_copy->log_relocated_nmethod(this);
1599 
1600       return nm_copy;
1601     }
1602   }
1603 
1604   nm_copy->make_not_used();
1605 
1606   return nullptr;
1607 }
1608 
1609 bool nmethod::is_relocatable() {
1610   if (!is_java_method()) {
1611     return false;
1612   }
1613 
1614   if (!is_in_use()) {
1615     return false;
1616   }
1617 
1618   if (is_osr_method()) {
1619     return false;
1620   }
1621 
1622   if (is_marked_for_deoptimization()) {
1623     return false;
1624   }
1625 
1626 #if INCLUDE_JVMCI
1627   if (jvmci_nmethod_data() != nullptr && jvmci_nmethod_data()->has_mirror()) {
1628     return false;
1629   }
1630 #endif
1631 
1632   if (is_unloading()) {
1633     return false;
1634   }
1635 
1636   if (has_evol_metadata()) {
1637     return false;
1638   }
1639 
1640   return true;
1641 }
1642 
1643 void* nmethod::operator new(size_t size, int nmethod_size, int comp_level) throw () {
1644   return CodeCache::allocate(nmethod_size, CodeCache::get_code_blob_type(comp_level));
1645 }
1646 
1647 void* nmethod::operator new(size_t size, int nmethod_size, CodeBlobType code_blob_type) throw () {
1648   return CodeCache::allocate(nmethod_size, code_blob_type);
1649 }
1650 
1651 void* nmethod::operator new(size_t size, int nmethod_size, bool allow_NonNMethod_space) throw () {
1652   // Try MethodNonProfiled and MethodProfiled.
1653   void* return_value = CodeCache::allocate(nmethod_size, CodeBlobType::MethodNonProfiled);
1654   if (return_value != nullptr || !allow_NonNMethod_space) return return_value;
1655   // Try NonNMethod or give up.
1656   return CodeCache::allocate(nmethod_size, CodeBlobType::NonNMethod);
1657 }
1658 
1659 // For normal JIT compiled code
1660 nmethod::nmethod(
1661   Method* method,
1662   CompilerType type,
1663   int nmethod_size,
1664   int immutable_data_size,
1665   int mutable_data_size,
1666   int compile_id,
1667   int entry_bci,
1668   address immutable_data,
1669   CodeOffsets* offsets,
1670   int orig_pc_offset,
1671   DebugInformationRecorder* debug_info,
1672   Dependencies* dependencies,
1673   CodeBuffer *code_buffer,
1674   int frame_size,
1675   OopMapSet* oop_maps,
1676   ExceptionHandlerTable* handler_table,
1677   ImplicitExceptionTable* nul_chk_table,
1678   AbstractCompiler* compiler,
1679   CompLevel comp_level
1680 #if INCLUDE_JVMCI
1681   , char* speculations,
1682   int speculations_len,
1683   JVMCINMethodData* jvmci_data
1684 #endif
1685   )
1686   : CodeBlob("nmethod", CodeBlobKind::Nmethod, code_buffer, nmethod_size, sizeof(nmethod),
1687              offsets->value(CodeOffsets::Frame_Complete), frame_size, oop_maps, false, mutable_data_size),
1688   _deoptimization_generation(0),
1689   _gc_epoch(CodeCache::gc_epoch()),
1690   _method(method),
1691   _osr_link(nullptr)
1692 {
1693   assert(debug_info->oop_recorder() == code_buffer->oop_recorder(), "shared OR");
1694   {
1695     DEBUG_ONLY(NoSafepointVerifier nsv;)
1696     assert_locked_or_safepoint(CodeCache_lock);
1697 
1698     init_defaults(code_buffer, offsets);
1699 
1700     _osr_entry_point = code_begin() + offsets->value(CodeOffsets::OSR_Entry);
1701     _entry_bci       = entry_bci;
1702     _compile_id      = compile_id;
1703     _comp_level      = comp_level;
1704     _compiler_type   = type;
1705     _orig_pc_offset  = orig_pc_offset;
1706 
1707     _num_stack_arg_slots = entry_bci != InvocationEntryBci ? 0 : _method->constMethod()->num_stack_arg_slots();
1708 
1709     set_ctable_begin(header_begin() + content_offset());
1710 
1711 #if INCLUDE_JVMCI
1712     if (compiler->is_jvmci()) {
1713       // JVMCI might not produce any stub sections
1714       if (offsets->value(CodeOffsets::Exceptions) != -1) {
1715         _exception_offset        = code_offset() + offsets->value(CodeOffsets::Exceptions);
1716       } else {
1717         _exception_offset        = -1;
1718       }
1719       if (offsets->value(CodeOffsets::Deopt) != -1) {
1720         _deopt_handler_entry_offset    = code_offset() + offsets->value(CodeOffsets::Deopt);
1721       } else {
1722         _deopt_handler_entry_offset    = -1;
1723       }
1724     } else
1725 #endif
1726     {
1727       // Exception handler and deopt handler are in the stub section
1728       assert(offsets->value(CodeOffsets::Deopt     ) != -1, "must be set");
1729 
1730       bool has_exception_handler = (offsets->value(CodeOffsets::Exceptions) != -1);
1731       assert(has_exception_handler == (compiler->type() != compiler_c2),
1732              "C2 compiler doesn't provide exception handler stub code.");
1733       if (has_exception_handler) {
1734         _exception_offset = _stub_offset + offsets->value(CodeOffsets::Exceptions);
1735       } else {
1736         _exception_offset = -1;
1737       }
1738 
1739       _deopt_handler_entry_offset = _stub_offset + offsets->value(CodeOffsets::Deopt);
1740     }
1741     if (offsets->value(CodeOffsets::UnwindHandler) != -1) {
1742       // C1 generates UnwindHandler at the end of instructions section.
1743       // Calculate positive offset as distance between the start of stubs section
1744       // (which is also the end of instructions section) and the start of the handler.
1745       int unwind_handler_offset = code_offset() + offsets->value(CodeOffsets::UnwindHandler);
1746       CHECKED_CAST(_unwind_handler_offset, int16_t, (_stub_offset - unwind_handler_offset));
1747     } else {
1748       _unwind_handler_offset = -1;
1749     }
1750 
1751     int metadata_size = align_up(code_buffer->total_metadata_size(), wordSize);
1752     JVMCI_ONLY( _metadata_size = metadata_size; )
1753     int jvmci_data_size = 0 JVMCI_ONLY( + align_up(compiler->is_jvmci() ? jvmci_data->size() : 0, oopSize));
1754     assert(_mutable_data_size == _relocation_size + metadata_size + jvmci_data_size,
1755            "wrong mutable data size: %d != %d + %d + %d",
1756            _mutable_data_size, _relocation_size, metadata_size, jvmci_data_size);
1757     assert(nmethod_size == data_end() - header_begin(), "wrong nmethod size: %d != %d",
1758            nmethod_size, (int)(code_end() - header_begin()));
1759 
1760     _immutable_data_size  = immutable_data_size;
1761     if (immutable_data_size > 0) {
1762       assert(immutable_data != nullptr, "required");
1763       _immutable_data     = immutable_data;
1764     } else {
1765       // We need unique not null address
1766       _immutable_data     = blob_end();
1767     }
1768     CHECKED_CAST(_nul_chk_table_offset, uint16_t, (align_up((int)dependencies->size_in_bytes(), oopSize)));
1769     CHECKED_CAST(_handler_table_offset, uint16_t, (_nul_chk_table_offset + align_up(nul_chk_table->size_in_bytes(), oopSize)));
1770     _scopes_pcs_offset    = _handler_table_offset + align_up(handler_table->size_in_bytes(), oopSize);
1771     _scopes_data_offset   = _scopes_pcs_offset    + adjust_pcs_size(debug_info->pcs_size());
1772 
1773 #if INCLUDE_JVMCI
1774     _speculations_offset  = _scopes_data_offset   + align_up(debug_info->data_size(), oopSize);
1775     _immutable_data_ref_count_offset = _speculations_offset + align_up(speculations_len, oopSize);
1776 #else
1777     _immutable_data_ref_count_offset = _scopes_data_offset + align_up(debug_info->data_size(), oopSize);
1778 #endif
1779     DEBUG_ONLY( int immutable_data_end_offset = _immutable_data_ref_count_offset + ImmutableDataRefCountSize; )
1780     assert(immutable_data_end_offset <= immutable_data_size, "wrong read-only data size: %d > %d",
1781            immutable_data_end_offset, immutable_data_size);
1782 
1783     // Copy code and relocation info
1784     code_buffer->copy_code_and_locs_to(this);
1785     // Copy oops and metadata
1786     code_buffer->copy_values_to(this);
1787     dependencies->copy_to(this);
1788     // Copy PcDesc and ScopeDesc data
1789     debug_info->copy_to(this);
1790 
1791     // Create cache after PcDesc data is copied - it will be used to initialize cache
1792     _pc_desc_container = new PcDescContainer(scopes_pcs_begin());
1793 
1794 #if INCLUDE_JVMCI
1795     if (compiler->is_jvmci()) {
1796       // Initialize the JVMCINMethodData object inlined into nm
1797       jvmci_nmethod_data()->copy(jvmci_data);
1798     }
1799 #endif
1800 
1801     // Copy contents of ExceptionHandlerTable to nmethod
1802     handler_table->copy_to(this);
1803     nul_chk_table->copy_to(this);
1804 
1805 #if INCLUDE_JVMCI
1806     // Copy speculations to nmethod
1807     if (speculations_size() != 0) {
1808       memcpy(speculations_begin(), speculations, speculations_len);
1809     }
1810 #endif
1811     init_immutable_data_ref_count();
1812 
1813     post_init();
1814 
1815     // we use the information of entry points to find out if a method is
1816     // static or non static
1817     assert(compiler->is_c2() || compiler->is_jvmci() ||
1818            _method->is_static() == (entry_point() == verified_entry_point()),
1819            " entry points must be same for static methods and vice versa");
1820   }
1821 }
1822 
1823 // Print a short set of xml attributes to identify this nmethod.  The
1824 // output should be embedded in some other element.
1825 void nmethod::log_identity(xmlStream* log) const {
1826   log->print(" compile_id='%d'", compile_id());
1827   const char* nm_kind = compile_kind();
1828   if (nm_kind != nullptr)  log->print(" compile_kind='%s'", nm_kind);
1829   log->print(" compiler='%s'", compiler_name());
1830   if (TieredCompilation) {
1831     log->print(" level='%d'", comp_level());
1832   }
1833 #if INCLUDE_JVMCI
1834   if (jvmci_nmethod_data() != nullptr) {
1835     const char* jvmci_name = jvmci_nmethod_data()->name();
1836     if (jvmci_name != nullptr) {
1837       log->print(" jvmci_mirror_name='");
1838       log->text("%s", jvmci_name);
1839       log->print("'");
1840     }
1841   }
1842 #endif
1843 }
1844 
1845 
1846 #define LOG_OFFSET(log, name)                    \
1847   if (p2i(name##_end()) - p2i(name##_begin())) \
1848     log->print(" " XSTR(name) "_offset='%zd'"    , \
1849                p2i(name##_begin()) - p2i(this))
1850 
1851 
1852 void nmethod::log_new_nmethod() const {
1853   if (LogCompilation && xtty != nullptr) {
1854     ttyLocker ttyl;
1855     xtty->begin_elem("nmethod");
1856     log_identity(xtty);
1857     xtty->print(" entry='" INTPTR_FORMAT "' size='%d'", p2i(code_begin()), size());
1858     xtty->print(" address='" INTPTR_FORMAT "'", p2i(this));
1859 
1860     LOG_OFFSET(xtty, relocation);
1861     LOG_OFFSET(xtty, consts);
1862     LOG_OFFSET(xtty, insts);
1863     LOG_OFFSET(xtty, stub);
1864     LOG_OFFSET(xtty, scopes_data);
1865     LOG_OFFSET(xtty, scopes_pcs);
1866     LOG_OFFSET(xtty, dependencies);
1867     LOG_OFFSET(xtty, handler_table);
1868     LOG_OFFSET(xtty, nul_chk_table);
1869     LOG_OFFSET(xtty, oops);
1870     LOG_OFFSET(xtty, metadata);
1871 
1872     xtty->method(method());
1873     xtty->stamp();
1874     xtty->end_elem();
1875   }
1876 }
1877 
1878 
1879 void nmethod::log_relocated_nmethod(nmethod* original) const {
1880   if (LogCompilation && xtty != nullptr) {
1881     ttyLocker ttyl;
1882     xtty->begin_elem("relocated nmethod");
1883     log_identity(xtty);
1884     xtty->print(" entry='" INTPTR_FORMAT "' size='%d'", p2i(code_begin()), size());
1885 
1886     const char* original_code_heap_name = CodeCache::get_code_heap_name(CodeCache::get_code_blob_type(original));
1887     xtty->print(" original_address='" INTPTR_FORMAT "'", p2i(original));
1888     xtty->print(" original_code_heap='%s'", original_code_heap_name);
1889 
1890     const char* new_code_heap_name = CodeCache::get_code_heap_name(CodeCache::get_code_blob_type(this));
1891     xtty->print(" new_address='" INTPTR_FORMAT "'", p2i(this));
1892     xtty->print(" new_code_heap='%s'", new_code_heap_name);
1893 
1894     LOG_OFFSET(xtty, relocation);
1895     LOG_OFFSET(xtty, consts);
1896     LOG_OFFSET(xtty, insts);
1897     LOG_OFFSET(xtty, stub);
1898     LOG_OFFSET(xtty, scopes_data);
1899     LOG_OFFSET(xtty, scopes_pcs);
1900     LOG_OFFSET(xtty, dependencies);
1901     LOG_OFFSET(xtty, handler_table);
1902     LOG_OFFSET(xtty, nul_chk_table);
1903     LOG_OFFSET(xtty, oops);
1904     LOG_OFFSET(xtty, metadata);
1905 
1906     xtty->method(method());
1907     xtty->stamp();
1908     xtty->end_elem();
1909   }
1910 }
1911 
1912 #undef LOG_OFFSET
1913 
1914 
1915 // Print out more verbose output usually for a newly created nmethod.
1916 void nmethod::print_on_with_msg(outputStream* st, const char* msg) const {
1917   if (st != nullptr) {
1918     ttyLocker ttyl;
1919     if (WizardMode) {
1920       CompileTask::print(st, this, msg, /*short_form:*/ true);
1921       st->print_cr(" (" INTPTR_FORMAT ")", p2i(this));
1922     } else {
1923       CompileTask::print(st, this, msg, /*short_form:*/ false);
1924     }
1925   }
1926 }
1927 
1928 void nmethod::maybe_print_nmethod(const DirectiveSet* directive) {
1929   bool printnmethods = directive->PrintAssemblyOption || directive->PrintNMethodsOption;
1930   if (printnmethods || PrintDebugInfo || PrintRelocations || PrintDependencies || PrintExceptionHandlers) {
1931     print_nmethod(printnmethods);
1932   }
1933 }
1934 
1935 void nmethod::print_nmethod(bool printmethod) {
1936   ttyLocker ttyl;  // keep the following output all in one block
1937   if (xtty != nullptr) {
1938     xtty->begin_head("print_nmethod");
1939     log_identity(xtty);
1940     xtty->stamp();
1941     xtty->end_head();
1942   }
1943   // Print the header part, then print the requested information.
1944   // This is both handled in decode2().
1945   if (printmethod) {
1946     ResourceMark m;
1947     if (is_compiled_by_c1()) {
1948       tty->cr();
1949       tty->print_cr("============================= C1-compiled nmethod ==============================");
1950     }
1951     if (is_compiled_by_jvmci()) {
1952       tty->cr();
1953       tty->print_cr("=========================== JVMCI-compiled nmethod =============================");
1954     }
1955     tty->print_cr("----------------------------------- Assembly -----------------------------------");
1956     decode2(tty);
1957 #if defined(SUPPORT_DATA_STRUCTS)
1958     if (AbstractDisassembler::show_structs()) {
1959       // Print the oops from the underlying CodeBlob as well.
1960       tty->print_cr("- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ");
1961       print_oops(tty);
1962       tty->print_cr("- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ");
1963       print_metadata(tty);
1964       tty->print_cr("- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ");
1965       print_pcs_on(tty);
1966       tty->print_cr("- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ");
1967       if (oop_maps() != nullptr) {
1968         tty->print("oop maps:"); // oop_maps()->print_on(tty) outputs a cr() at the beginning
1969         oop_maps()->print_on(tty);
1970         tty->print_cr("- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ");
1971       }
1972     }
1973 #endif
1974   } else {
1975     print(); // print the header part only.
1976   }
1977 
1978 #if defined(SUPPORT_DATA_STRUCTS)
1979   if (AbstractDisassembler::show_structs()) {
1980     methodHandle mh(Thread::current(), _method);
1981     if (printmethod || PrintDebugInfo || CompilerOracle::has_option(mh, CompileCommandEnum::PrintDebugInfo)) {
1982       print_scopes();
1983       tty->print_cr("- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ");
1984     }
1985     if (printmethod || PrintRelocations || CompilerOracle::has_option(mh, CompileCommandEnum::PrintRelocations)) {
1986       print_relocations();
1987       tty->print_cr("- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ");
1988     }
1989     if (printmethod || PrintDependencies || CompilerOracle::has_option(mh, CompileCommandEnum::PrintDependencies)) {
1990       print_dependencies_on(tty);
1991       tty->print_cr("- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ");
1992     }
1993     if (printmethod || PrintExceptionHandlers) {
1994       print_handler_table();
1995       tty->print_cr("- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ");
1996       print_nul_chk_table();
1997       tty->print_cr("- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ");
1998     }
1999 
2000     if (printmethod) {
2001       print_recorded_oops();
2002       tty->print_cr("- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ");
2003       print_recorded_metadata();
2004       tty->print_cr("- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ");
2005     }
2006   }
2007 #endif
2008 
2009   if (xtty != nullptr) {
2010     xtty->tail("print_nmethod");
2011   }
2012 }
2013 
2014 
2015 // Promote one word from an assembly-time handle to a live embedded oop.
2016 inline void nmethod::initialize_immediate_oop(oop* dest, jobject handle) {
2017   if (handle == nullptr ||
2018       // As a special case, IC oops are initialized to 1 or -1.
2019       handle == (jobject) Universe::non_oop_word()) {
2020     *(void**)dest = handle;
2021   } else {
2022     *dest = JNIHandles::resolve_non_null(handle);
2023   }
2024 }
2025 
2026 
2027 // Have to have the same name because it's called by a template
2028 void nmethod::copy_values(GrowableArray<jobject>* array) {
2029   int length = array->length();
2030   assert((address)(oops_begin() + length) <= (address)oops_end(), "oops big enough");
2031   oop* dest = oops_begin();
2032   for (int index = 0 ; index < length; index++) {
2033     initialize_immediate_oop(&dest[index], array->at(index));
2034   }
2035 
2036   // Now we can fix up all the oops in the code.  We need to do this
2037   // in the code because the assembler uses jobjects as placeholders.
2038   // The code and relocations have already been initialized by the
2039   // CodeBlob constructor, so it is valid even at this early point to
2040   // iterate over relocations and patch the code.
2041   fix_oop_relocations(nullptr, nullptr, /*initialize_immediates=*/ true);
2042 }
2043 
2044 void nmethod::copy_values(GrowableArray<Metadata*>* array) {
2045   int length = array->length();
2046   assert((address)(metadata_begin() + length) <= (address)metadata_end(), "big enough");
2047   Metadata** dest = metadata_begin();
2048   for (int index = 0 ; index < length; index++) {
2049     dest[index] = array->at(index);
2050   }
2051 }
2052 
2053 void nmethod::fix_oop_relocations(address begin, address end, bool initialize_immediates) {
2054   // re-patch all oop-bearing instructions, just in case some oops moved
2055   RelocIterator iter(this, begin, end);
2056   while (iter.next()) {
2057     if (iter.type() == relocInfo::oop_type) {
2058       oop_Relocation* reloc = iter.oop_reloc();
2059       if (initialize_immediates && reloc->oop_is_immediate()) {
2060         oop* dest = reloc->oop_addr();
2061         jobject obj = *reinterpret_cast<jobject*>(dest);
2062         initialize_immediate_oop(dest, obj);
2063       }
2064       // Refresh the oop-related bits of this instruction.
2065       reloc->fix_oop_relocation();
2066     } else if (iter.type() == relocInfo::metadata_type) {
2067       metadata_Relocation* reloc = iter.metadata_reloc();
2068       reloc->fix_metadata_relocation();
2069     }
2070   }
2071 }
2072 
2073 static void install_post_call_nop_displacement(nmethod* nm, address pc) {
2074   NativePostCallNop* nop = nativePostCallNop_at((address) pc);
2075   intptr_t cbaddr = (intptr_t) nm;
2076   intptr_t offset = ((intptr_t) pc) - cbaddr;
2077 
2078   int oopmap_slot = nm->oop_maps()->find_slot_for_offset(int((intptr_t) pc - (intptr_t) nm->code_begin()));
2079   if (oopmap_slot < 0) { // this can happen at asynchronous (non-safepoint) stackwalks
2080     log_debug(codecache)("failed to find oopmap for cb: " INTPTR_FORMAT " offset: %d", cbaddr, (int) offset);
2081   } else if (!nop->patch(oopmap_slot, offset)) {
2082     log_debug(codecache)("failed to encode %d %d", oopmap_slot, (int) offset);
2083   }
2084 }
2085 
2086 void nmethod::finalize_relocations() {
2087   NoSafepointVerifier nsv;
2088 
2089   GrowableArray<NativeMovConstReg*> virtual_call_data;
2090 
2091   // Make sure that post call nops fill in nmethod offsets eagerly so
2092   // we don't have to race with deoptimization
2093   RelocIterator iter(this);
2094   while (iter.next()) {
2095     if (iter.type() == relocInfo::virtual_call_type) {
2096       virtual_call_Relocation* r = iter.virtual_call_reloc();
2097       NativeMovConstReg* value = nativeMovConstReg_at(r->cached_value());
2098       virtual_call_data.append(value);
2099     } else if (iter.type() == relocInfo::post_call_nop_type) {
2100       post_call_nop_Relocation* const reloc = iter.post_call_nop_reloc();
2101       address pc = reloc->addr();
2102       install_post_call_nop_displacement(this, pc);
2103     }
2104   }
2105 
2106   if (virtual_call_data.length() > 0) {
2107     // We allocate a block of CompiledICData per nmethod so the GC can purge this faster.
2108     _compiled_ic_data = new CompiledICData[virtual_call_data.length()];
2109     CompiledICData* next_data = _compiled_ic_data;
2110 
2111     for (NativeMovConstReg* value : virtual_call_data) {
2112       value->set_data((intptr_t)next_data);
2113       next_data++;
2114     }
2115   }
2116 }
2117 
2118 void nmethod::make_deoptimized() {
2119   if (!Continuations::enabled()) {
2120     // Don't deopt this again.
2121     set_deoptimized_done();
2122     return;
2123   }
2124 
2125   assert(method() == nullptr || can_be_deoptimized(), "");
2126 
2127   CompiledICLocker ml(this);
2128   assert(CompiledICLocker::is_safe(this), "mt unsafe call");
2129 
2130   // If post call nops have been already patched, we can just bail-out.
2131   if (has_been_deoptimized()) {
2132     return;
2133   }
2134 
2135   ResourceMark rm;
2136   RelocIterator iter(this, oops_reloc_begin());
2137 
2138   // Assume there will be some calls to make deoptimized.
2139   MACOS_AARCH64_ONLY(os::thread_wx_enable_write());
2140 
2141   while (iter.next()) {
2142 
2143     switch (iter.type()) {
2144       case relocInfo::virtual_call_type: {
2145         CompiledIC *ic = CompiledIC_at(&iter);
2146         address pc = ic->end_of_call();
2147         NativePostCallNop* nop = nativePostCallNop_at(pc);
2148         if (nop != nullptr) {
2149           nop->make_deopt();
2150         }
2151         assert(NativeDeoptInstruction::is_deopt_at(pc), "check");
2152         break;
2153       }
2154       case relocInfo::static_call_type:
2155       case relocInfo::opt_virtual_call_type: {
2156         CompiledDirectCall *csc = CompiledDirectCall::at(iter.reloc());
2157         address pc = csc->end_of_call();
2158         NativePostCallNop* nop = nativePostCallNop_at(pc);
2159         //tty->print_cr(" - static pc %p", pc);
2160         if (nop != nullptr) {
2161           nop->make_deopt();
2162         }
2163         // We can't assert here, there are some calls to stubs / runtime
2164         // that have reloc data and doesn't have a post call NOP.
2165         //assert(NativeDeoptInstruction::is_deopt_at(pc), "check");
2166         break;
2167       }
2168       default:
2169         break;
2170     }
2171   }
2172   // Don't deopt this again.
2173   set_deoptimized_done();
2174 }
2175 
2176 void nmethod::verify_clean_inline_caches() {
2177   assert(CompiledICLocker::is_safe(this), "mt unsafe call");
2178 
2179   ResourceMark rm;
2180   RelocIterator iter(this, oops_reloc_begin());
2181   while(iter.next()) {
2182     switch(iter.type()) {
2183       case relocInfo::virtual_call_type: {
2184         CompiledIC *ic = CompiledIC_at(&iter);
2185         CodeBlob *cb = CodeCache::find_blob(ic->destination());
2186         assert(cb != nullptr, "destination not in CodeBlob?");
2187         nmethod* nm = cb->as_nmethod_or_null();
2188         if (nm != nullptr) {
2189           // Verify that inline caches pointing to bad nmethods are clean
2190           if (!nm->is_in_use() || nm->is_unloading()) {
2191             assert(ic->is_clean(), "IC should be clean");
2192           }
2193         }
2194         break;
2195       }
2196       case relocInfo::static_call_type:
2197       case relocInfo::opt_virtual_call_type: {
2198         CompiledDirectCall *cdc = CompiledDirectCall::at(iter.reloc());
2199         CodeBlob *cb = CodeCache::find_blob(cdc->destination());
2200         assert(cb != nullptr, "destination not in CodeBlob?");
2201         nmethod* nm = cb->as_nmethod_or_null();
2202         if (nm != nullptr) {
2203           // Verify that inline caches pointing to bad nmethods are clean
2204           if (!nm->is_in_use() || nm->is_unloading() || nm->method()->code() != nm) {
2205             assert(cdc->is_clean(), "IC should be clean");
2206           }
2207         }
2208         break;
2209       }
2210       default:
2211         break;
2212     }
2213   }
2214 }
2215 
2216 void nmethod::mark_as_maybe_on_stack() {
2217   MACOS_AARCH64_ONLY(os::thread_wx_enable_write());
2218   AtomicAccess::store(&_gc_epoch, CodeCache::gc_epoch());
2219 }
2220 
2221 bool nmethod::is_maybe_on_stack() {
2222   // If the condition below is true, it means that the nmethod was found to
2223   // be alive the previous completed marking cycle.
2224   return AtomicAccess::load(&_gc_epoch) >= CodeCache::previous_completed_gc_marking_cycle();
2225 }
2226 
2227 void nmethod::inc_decompile_count() {
2228   if (!is_compiled_by_c2() && !is_compiled_by_jvmci()) return;
2229   // Could be gated by ProfileTraps, but do not bother...
2230 #if INCLUDE_JVMCI
2231   if (jvmci_skip_profile_deopt()) {
2232     return;
2233   }
2234 #endif
2235   Method* m = method();
2236   if (m == nullptr)  return;
2237   MethodData* mdo = m->method_data();
2238   if (mdo == nullptr)  return;
2239   // There is a benign race here.  See comments in methodData.hpp.
2240   mdo->inc_decompile_count();
2241 }
2242 
2243 bool nmethod::try_transition(signed char new_state_int) {
2244   signed char new_state = new_state_int;
2245   assert_lock_strong(NMethodState_lock);
2246   signed char old_state = _state;
2247   if (old_state >= new_state) {
2248     // Ensure monotonicity of transitions.
2249     return false;
2250   }
2251   AtomicAccess::store(&_state, new_state);
2252   return true;
2253 }
2254 
2255 void nmethod::invalidate_osr_method() {
2256   assert(_entry_bci != InvocationEntryBci, "wrong kind of nmethod");
2257   // Remove from list of active nmethods
2258   if (method() != nullptr) {
2259     method()->method_holder()->remove_osr_nmethod(this);
2260   }
2261 }
2262 
2263 void nmethod::log_state_change(InvalidationReason invalidation_reason) const {
2264   if (LogCompilation) {
2265     if (xtty != nullptr) {
2266       ttyLocker ttyl;  // keep the following output all in one block
2267       xtty->begin_elem("make_not_entrant thread='%zu' reason='%s'",
2268                        os::current_thread_id(), invalidation_reason_to_string(invalidation_reason));
2269       log_identity(xtty);
2270       xtty->stamp();
2271       xtty->end_elem();
2272     }
2273   }
2274 
2275   ResourceMark rm;
2276   stringStream ss(NEW_RESOURCE_ARRAY(char, 256), 256);
2277   ss.print("made not entrant: %s", invalidation_reason_to_string(invalidation_reason));
2278 
2279   CompileTask::print_ul(this, ss.freeze());
2280   if (PrintCompilation) {
2281     print_on_with_msg(tty, ss.freeze());
2282   }
2283 }
2284 
2285 void nmethod::unlink_from_method() {
2286   if (method() != nullptr) {
2287     method()->unlink_code(this);
2288   }
2289 }
2290 
2291 // Invalidate code
2292 bool nmethod::make_not_entrant(InvalidationReason invalidation_reason) {
2293   // This can be called while the system is already at a safepoint which is ok
2294   NoSafepointVerifier nsv;
2295 
2296   if (is_unloading()) {
2297     // If the nmethod is unloading, then it is already not entrant through
2298     // the nmethod entry barriers. No need to do anything; GC will unload it.
2299     return false;
2300   }
2301 
2302   if (AtomicAccess::load(&_state) == not_entrant) {
2303     // Avoid taking the lock if already in required state.
2304     // This is safe from races because the state is an end-state,
2305     // which the nmethod cannot back out of once entered.
2306     // No need for fencing either.
2307     return false;
2308   }
2309 
2310   MACOS_AARCH64_ONLY(os::thread_wx_enable_write());
2311 
2312   {
2313     // Enter critical section.  Does not block for safepoint.
2314     ConditionalMutexLocker ml(NMethodState_lock, !NMethodState_lock->owned_by_self(), Mutex::_no_safepoint_check_flag);
2315 
2316     if (AtomicAccess::load(&_state) == not_entrant) {
2317       // another thread already performed this transition so nothing
2318       // to do, but return false to indicate this.
2319       return false;
2320     }
2321 
2322     if (is_osr_method()) {
2323       // This logic is equivalent to the logic below for patching the
2324       // verified entry point of regular methods.
2325       // this effectively makes the osr nmethod not entrant
2326       invalidate_osr_method();
2327     } else {
2328       // The caller can be calling the method statically or through an inline
2329       // cache call.
2330       BarrierSet::barrier_set()->barrier_set_nmethod()->make_not_entrant(this);
2331     }
2332 
2333     if (update_recompile_counts()) {
2334       // Mark the method as decompiled.
2335       inc_decompile_count();
2336     }
2337 
2338     BarrierSetNMethod* bs_nm = BarrierSet::barrier_set()->barrier_set_nmethod();
2339     if (bs_nm == nullptr || !bs_nm->supports_entry_barrier(this)) {
2340       // If nmethod entry barriers are not supported, we won't mark
2341       // nmethods as on-stack when they become on-stack. So we
2342       // degrade to a less accurate flushing strategy, for now.
2343       mark_as_maybe_on_stack();
2344     }
2345 
2346     // Change state
2347     bool success = try_transition(not_entrant);
2348     assert(success, "Transition can't fail");
2349 
2350     // Log the transition once
2351     log_state_change(invalidation_reason);
2352 
2353     // Remove nmethod from method.
2354     unlink_from_method();
2355 
2356   } // leave critical region under NMethodState_lock
2357 
2358 #if INCLUDE_JVMCI
2359   // Invalidate can't occur while holding the NMethodState_lock
2360   JVMCINMethodData* nmethod_data = jvmci_nmethod_data();
2361   if (nmethod_data != nullptr) {
2362     nmethod_data->invalidate_nmethod_mirror(this, invalidation_reason);
2363   }
2364 #endif
2365 
2366 #ifdef ASSERT
2367   if (is_osr_method() && method() != nullptr) {
2368     // Make sure osr nmethod is invalidated, i.e. not on the list
2369     bool found = method()->method_holder()->remove_osr_nmethod(this);
2370     assert(!found, "osr nmethod should have been invalidated");
2371   }
2372 #endif
2373 
2374   return true;
2375 }
2376 
2377 // For concurrent GCs, there must be a handshake between unlink and flush
2378 void nmethod::unlink() {
2379   if (is_unlinked()) {
2380     // Already unlinked.
2381     return;
2382   }
2383 
2384   flush_dependencies();
2385 
2386   // unlink_from_method will take the NMethodState_lock.
2387   // In this case we don't strictly need it when unlinking nmethods from
2388   // the Method, because it is only concurrently unlinked by
2389   // the entry barrier, which acquires the per nmethod lock.
2390   unlink_from_method();
2391 
2392   if (is_osr_method()) {
2393     invalidate_osr_method();
2394   }
2395 
2396 #if INCLUDE_JVMCI
2397   // Clear the link between this nmethod and a HotSpotNmethod mirror
2398   JVMCINMethodData* nmethod_data = jvmci_nmethod_data();
2399   if (nmethod_data != nullptr) {
2400     nmethod_data->invalidate_nmethod_mirror(this, is_cold() ?
2401             nmethod::InvalidationReason::UNLOADING_COLD :
2402             nmethod::InvalidationReason::UNLOADING);
2403   }
2404 #endif
2405 
2406   // Post before flushing as jmethodID is being used
2407   post_compiled_method_unload();
2408 
2409   // Register for flushing when it is safe. For concurrent class unloading,
2410   // that would be after the unloading handshake, and for STW class unloading
2411   // that would be when getting back to the VM thread.
2412   ClassUnloadingContext::context()->register_unlinked_nmethod(this);
2413 }
2414 
2415 void nmethod::purge(bool unregister_nmethod) {
2416 
2417   MutexLocker ml(CodeCache_lock, Mutex::_no_safepoint_check_flag);
2418 
2419   // completely deallocate this method
2420   Events::log_nmethod_flush(Thread::current(), "flushing %s nmethod " INTPTR_FORMAT, is_osr_method() ? "osr" : "", p2i(this));
2421 
2422   LogTarget(Debug, codecache) lt;
2423   if (lt.is_enabled()) {
2424     ResourceMark rm;
2425     LogStream ls(lt);
2426     const char* method_name = method()->name()->as_C_string();
2427     const size_t codecache_capacity = CodeCache::capacity()/1024;
2428     const size_t codecache_free_space = CodeCache::unallocated_capacity(CodeCache::get_code_blob_type(this))/1024;
2429     ls.print("Flushing nmethod %6d/" INTPTR_FORMAT ", level=%d, osr=%d, cold=%d, epoch=" UINT64_FORMAT ", cold_count=" UINT64_FORMAT ". "
2430               "Cache capacity: %zuKb, free space: %zuKb. method %s (%s)",
2431               _compile_id, p2i(this), _comp_level, is_osr_method(), is_cold(), _gc_epoch, CodeCache::cold_gc_count(),
2432               codecache_capacity, codecache_free_space, method_name, compiler_name());
2433   }
2434 
2435   // We need to deallocate any ExceptionCache data.
2436   // Note that we do not need to grab the nmethod lock for this, it
2437   // better be thread safe if we're disposing of it!
2438   ExceptionCache* ec = exception_cache();
2439   while(ec != nullptr) {
2440     ExceptionCache* next = ec->next();
2441     delete ec;
2442     ec = next;
2443   }
2444   if (_pc_desc_container != nullptr) {
2445     delete _pc_desc_container;
2446   }
2447   delete[] _compiled_ic_data;
2448 
2449   if (_immutable_data != blob_end()) {
2450     // Free memory if this was the last nmethod referencing immutable data
2451     if (dec_immutable_data_ref_count() == 0) {
2452       os::free(_immutable_data);
2453     }
2454 
2455     _immutable_data = blob_end(); // Valid not null address
2456   }
2457 
2458   if (unregister_nmethod) {
2459     Universe::heap()->unregister_nmethod(this);
2460   }
2461   CodeCache::unregister_old_nmethod(this);
2462 
2463   JVMCI_ONLY( _metadata_size = 0; )
2464   CodeBlob::purge();
2465 }
2466 
2467 oop nmethod::oop_at(int index) const {
2468   if (index == 0) {
2469     return nullptr;
2470   }
2471 
2472   BarrierSetNMethod* bs_nm = BarrierSet::barrier_set()->barrier_set_nmethod();
2473   return bs_nm->oop_load_no_keepalive(this, index);
2474 }
2475 
2476 oop nmethod::oop_at_phantom(int index) const {
2477   if (index == 0) {
2478     return nullptr;
2479   }
2480 
2481   BarrierSetNMethod* bs_nm = BarrierSet::barrier_set()->barrier_set_nmethod();
2482   return bs_nm->oop_load_phantom(this, index);
2483 }
2484 
2485 //
2486 // Notify all classes this nmethod is dependent on that it is no
2487 // longer dependent.
2488 
2489 void nmethod::flush_dependencies() {
2490   if (!has_flushed_dependencies()) {
2491     set_has_flushed_dependencies(true);
2492     for (Dependencies::DepStream deps(this); deps.next(); ) {
2493       if (deps.type() == Dependencies::call_site_target_value) {
2494         // CallSite dependencies are managed on per-CallSite instance basis.
2495         oop call_site = deps.argument_oop(0);
2496         MethodHandles::clean_dependency_context(call_site);
2497       } else {
2498         InstanceKlass* ik = deps.context_type();
2499         if (ik == nullptr) {
2500           continue;  // ignore things like evol_method
2501         }
2502         // During GC liveness of dependee determines class that needs to be updated.
2503         // The GC may clean dependency contexts concurrently and in parallel.
2504         ik->clean_dependency_context();
2505       }
2506     }
2507   }
2508 }
2509 
2510 void nmethod::post_compiled_method(CompileTask* task) {
2511   task->mark_success();
2512   task->set_nm_content_size(content_size());
2513   task->set_nm_insts_size(insts_size());
2514   task->set_nm_total_size(total_size());
2515 
2516   // JVMTI -- compiled method notification (must be done outside lock)
2517   post_compiled_method_load_event();
2518 
2519   if (CompilationLog::log() != nullptr) {
2520     CompilationLog::log()->log_nmethod(JavaThread::current(), this);
2521   }
2522 
2523   const DirectiveSet* directive = task->directive();
2524   maybe_print_nmethod(directive);
2525 }
2526 
2527 #if INCLUDE_CDS
2528 static GrowableArrayCHeap<nmethod*, mtClassShared>* _delayed_compiled_method_load_events = nullptr;
2529 
2530 void nmethod::add_delayed_compiled_method_load_event(nmethod* nm) {
2531   precond(CDSConfig::is_using_aot_linked_classes());
2532   precond(!ServiceThread::has_started());
2533 
2534   // We are still in single threaded stage of VM bootstrap. No need to lock.
2535   if (_delayed_compiled_method_load_events == nullptr) {
2536     _delayed_compiled_method_load_events = new GrowableArrayCHeap<nmethod*, mtClassShared>();
2537   }
2538   _delayed_compiled_method_load_events->append(nm);
2539 }
2540 
2541 void nmethod::post_delayed_compiled_method_load_events() {
2542   precond(ServiceThread::has_started());
2543   if (_delayed_compiled_method_load_events != nullptr) {
2544     for (int i = 0; i < _delayed_compiled_method_load_events->length(); i++) {
2545       nmethod* nm = _delayed_compiled_method_load_events->at(i);
2546       nm->post_compiled_method_load_event();
2547     }
2548     delete _delayed_compiled_method_load_events;
2549     _delayed_compiled_method_load_events = nullptr;
2550   }
2551 }
2552 #endif
2553 
2554 // ------------------------------------------------------------------
2555 // post_compiled_method_load_event
2556 // new method for install_code() path
2557 // Transfer information from compilation to jvmti
2558 void nmethod::post_compiled_method_load_event(JvmtiThreadState* state) {
2559 #if INCLUDE_CDS
2560   if (!ServiceThread::has_started()) {
2561     // With AOT-linked classes, we could compile wrappers for native methods before the
2562     // ServiceThread has been started, so we must delay the events to be posted later.
2563     assert(state == nullptr, "must be");
2564     add_delayed_compiled_method_load_event(this);
2565     return;
2566   }
2567 #endif
2568 
2569   // This is a bad time for a safepoint.  We don't want
2570   // this nmethod to get unloaded while we're queueing the event.
2571   NoSafepointVerifier nsv;
2572 
2573   Method* m = method();
2574   HOTSPOT_COMPILED_METHOD_LOAD(
2575       (char *) m->klass_name()->bytes(),
2576       m->klass_name()->utf8_length(),
2577       (char *) m->name()->bytes(),
2578       m->name()->utf8_length(),
2579       (char *) m->signature()->bytes(),
2580       m->signature()->utf8_length(),
2581       insts_begin(), insts_size());
2582 
2583 
2584   if (JvmtiExport::should_post_compiled_method_load()) {
2585     // Only post unload events if load events are found.
2586     set_load_reported();
2587     // If a JavaThread hasn't been passed in, let the Service thread
2588     // (which is a real Java thread) post the event
2589     JvmtiDeferredEvent event = JvmtiDeferredEvent::compiled_method_load_event(this);
2590     if (state == nullptr) {
2591       // Execute any barrier code for this nmethod as if it's called, since
2592       // keeping it alive looks like stack walking.
2593       run_nmethod_entry_barrier();
2594       ServiceThread::enqueue_deferred_event(&event);
2595     } else {
2596       // This enters the nmethod barrier outside in the caller.
2597       state->enqueue_event(&event);
2598     }
2599   }
2600 }
2601 
2602 void nmethod::post_compiled_method_unload() {
2603   assert(_method != nullptr, "just checking");
2604   DTRACE_METHOD_UNLOAD_PROBE(method());
2605 
2606   // If a JVMTI agent has enabled the CompiledMethodUnload event then
2607   // post the event. The Method* will not be valid when this is freed.
2608 
2609   // Don't bother posting the unload if the load event wasn't posted.
2610   if (load_reported() && JvmtiExport::should_post_compiled_method_unload()) {
2611     JvmtiDeferredEvent event =
2612       JvmtiDeferredEvent::compiled_method_unload_event(
2613           method()->jmethod_id(), insts_begin());
2614     ServiceThread::enqueue_deferred_event(&event);
2615   }
2616 }
2617 
2618 // Iterate over metadata calling this function.   Used by RedefineClasses
2619 void nmethod::metadata_do(MetadataClosure* f) {
2620   {
2621     // Visit all immediate references that are embedded in the instruction stream.
2622     RelocIterator iter(this, oops_reloc_begin());
2623     while (iter.next()) {
2624       if (iter.type() == relocInfo::metadata_type) {
2625         metadata_Relocation* r = iter.metadata_reloc();
2626         // In this metadata, we must only follow those metadatas directly embedded in
2627         // the code.  Other metadatas (oop_index>0) are seen as part of
2628         // the metadata section below.
2629         assert(1 == (r->metadata_is_immediate()) +
2630                (r->metadata_addr() >= metadata_begin() && r->metadata_addr() < metadata_end()),
2631                "metadata must be found in exactly one place");
2632         if (r->metadata_is_immediate() && r->metadata_value() != nullptr) {
2633           Metadata* md = r->metadata_value();
2634           if (md != _method) f->do_metadata(md);
2635         }
2636       } else if (iter.type() == relocInfo::virtual_call_type) {
2637         // Check compiledIC holders associated with this nmethod
2638         ResourceMark rm;
2639         CompiledIC *ic = CompiledIC_at(&iter);
2640         ic->metadata_do(f);
2641       }
2642     }
2643   }
2644 
2645   // Visit the metadata section
2646   for (Metadata** p = metadata_begin(); p < metadata_end(); p++) {
2647     if (*p == Universe::non_oop_word() || *p == nullptr)  continue;  // skip non-oops
2648     Metadata* md = *p;
2649     f->do_metadata(md);
2650   }
2651 
2652   // Visit metadata not embedded in the other places.
2653   if (_method != nullptr) f->do_metadata(_method);
2654 }
2655 
2656 // Heuristic for nuking nmethods even though their oops are live.
2657 // Main purpose is to reduce code cache pressure and get rid of
2658 // nmethods that don't seem to be all that relevant any longer.
2659 bool nmethod::is_cold() {
2660   if (!MethodFlushing || is_not_installed()) {
2661     // No heuristic unloading at all
2662     return false;
2663   }
2664 
2665   if (!is_maybe_on_stack() && is_not_entrant()) {
2666     // Not entrant nmethods that are not on any stack can just
2667     // be removed
2668     return true;
2669   }
2670 
2671   BarrierSetNMethod* bs_nm = BarrierSet::barrier_set()->barrier_set_nmethod();
2672   if (bs_nm == nullptr || !bs_nm->supports_entry_barrier(this)) {
2673     // On platforms that don't support nmethod entry barriers, we can't
2674     // trust the temporal aspect of the gc epochs. So we can't detect
2675     // cold nmethods on such platforms.
2676     return false;
2677   }
2678 
2679   if (!UseCodeCacheFlushing) {
2680     // Bail out if we don't heuristically remove nmethods
2681     return false;
2682   }
2683 
2684   // Other code can be phased out more gradually after N GCs
2685   return CodeCache::previous_completed_gc_marking_cycle() > _gc_epoch + 2 * CodeCache::cold_gc_count();
2686 }
2687 
2688 // The _is_unloading_state encodes a tuple comprising the unloading cycle
2689 // and the result of IsUnloadingBehaviour::is_unloading() for that cycle.
2690 // This is the bit layout of the _is_unloading_state byte: 00000CCU
2691 // CC refers to the cycle, which has 2 bits, and U refers to the result of
2692 // IsUnloadingBehaviour::is_unloading() for that unloading cycle.
2693 
2694 class IsUnloadingState: public AllStatic {
2695   static const uint8_t _is_unloading_mask = 1;
2696   static const uint8_t _is_unloading_shift = 0;
2697   static const uint8_t _unloading_cycle_mask = 6;
2698   static const uint8_t _unloading_cycle_shift = 1;
2699 
2700   static uint8_t set_is_unloading(uint8_t state, bool value) {
2701     state &= (uint8_t)~_is_unloading_mask;
2702     if (value) {
2703       state |= 1 << _is_unloading_shift;
2704     }
2705     assert(is_unloading(state) == value, "unexpected unloading cycle overflow");
2706     return state;
2707   }
2708 
2709   static uint8_t set_unloading_cycle(uint8_t state, uint8_t value) {
2710     state &= (uint8_t)~_unloading_cycle_mask;
2711     state |= (uint8_t)(value << _unloading_cycle_shift);
2712     assert(unloading_cycle(state) == value, "unexpected unloading cycle overflow");
2713     return state;
2714   }
2715 
2716 public:
2717   static bool is_unloading(uint8_t state) { return (state & _is_unloading_mask) >> _is_unloading_shift == 1; }
2718   static uint8_t unloading_cycle(uint8_t state) { return (state & _unloading_cycle_mask) >> _unloading_cycle_shift; }
2719 
2720   static uint8_t create(bool is_unloading, uint8_t unloading_cycle) {
2721     uint8_t state = 0;
2722     state = set_is_unloading(state, is_unloading);
2723     state = set_unloading_cycle(state, unloading_cycle);
2724     return state;
2725   }
2726 };
2727 
2728 bool nmethod::is_unloading() {
2729   uint8_t state = AtomicAccess::load(&_is_unloading_state);
2730   bool state_is_unloading = IsUnloadingState::is_unloading(state);
2731   if (state_is_unloading) {
2732     return true;
2733   }
2734   uint8_t state_unloading_cycle = IsUnloadingState::unloading_cycle(state);
2735   uint8_t current_cycle = CodeCache::unloading_cycle();
2736   if (state_unloading_cycle == current_cycle) {
2737     return false;
2738   }
2739 
2740   // The IsUnloadingBehaviour is responsible for calculating if the nmethod
2741   // should be unloaded. This can be either because there is a dead oop,
2742   // or because is_cold() heuristically determines it is time to unload.
2743   state_unloading_cycle = current_cycle;
2744   state_is_unloading = IsUnloadingBehaviour::is_unloading(this);
2745   uint8_t new_state = IsUnloadingState::create(state_is_unloading, state_unloading_cycle);
2746 
2747   MACOS_AARCH64_ONLY(os::thread_wx_enable_write());
2748 
2749   // Note that if an nmethod has dead oops, everyone will agree that the
2750   // nmethod is_unloading. However, the is_cold heuristics can yield
2751   // different outcomes, so we guard the computed result with a CAS
2752   // to ensure all threads have a shared view of whether an nmethod
2753   // is_unloading or not.
2754   uint8_t found_state = AtomicAccess::cmpxchg(&_is_unloading_state, state, new_state, memory_order_relaxed);
2755 
2756   if (found_state == state) {
2757     // First to change state, we win
2758     return state_is_unloading;
2759   } else {
2760     // State already set, so use it
2761     return IsUnloadingState::is_unloading(found_state);
2762   }
2763 }
2764 
2765 void nmethod::clear_unloading_state() {
2766   uint8_t state = IsUnloadingState::create(false, CodeCache::unloading_cycle());
2767   AtomicAccess::store(&_is_unloading_state, state);
2768 }
2769 
2770 
2771 // This is called at the end of the strong tracing/marking phase of a
2772 // GC to unload an nmethod if it contains otherwise unreachable
2773 // oops or is heuristically found to be not important.
2774 void nmethod::do_unloading(bool unloading_occurred) {
2775   // Make sure the oop's ready to receive visitors
2776   if (is_unloading()) {
2777     unlink();
2778   } else {
2779     unload_nmethod_caches(unloading_occurred);
2780     BarrierSetNMethod* bs_nm = BarrierSet::barrier_set()->barrier_set_nmethod();
2781     if (bs_nm != nullptr) {
2782       bs_nm->disarm(this);
2783     }
2784   }
2785 }
2786 
2787 void nmethod::oops_do(OopClosure* f) {
2788   // Prevent extra code cache walk for platforms that don't have immediate oops.
2789   if (relocInfo::mustIterateImmediateOopsInCode()) {
2790     RelocIterator iter(this, oops_reloc_begin());
2791 
2792     while (iter.next()) {
2793       if (iter.type() == relocInfo::oop_type ) {
2794         oop_Relocation* r = iter.oop_reloc();
2795         // In this loop, we must only follow those oops directly embedded in
2796         // the code.  Other oops (oop_index>0) are seen as part of scopes_oops.
2797         assert(1 == (r->oop_is_immediate()) +
2798                (r->oop_addr() >= oops_begin() && r->oop_addr() < oops_end()),
2799                "oop must be found in exactly one place");
2800         if (r->oop_is_immediate() && r->oop_value() != nullptr) {
2801           f->do_oop(r->oop_addr());
2802         }
2803       }
2804     }
2805   }
2806 
2807   // Scopes
2808   // This includes oop constants not inlined in the code stream.
2809   for (oop* p = oops_begin(); p < oops_end(); p++) {
2810     if (*p == Universe::non_oop_word())  continue;  // skip non-oops
2811     f->do_oop(p);
2812   }
2813 }
2814 
2815 void nmethod::follow_nmethod(OopIterateClosure* cl) {
2816   // Process oops in the nmethod
2817   oops_do(cl);
2818 
2819   // CodeCache unloading support
2820   mark_as_maybe_on_stack();
2821 
2822   BarrierSetNMethod* bs_nm = BarrierSet::barrier_set()->barrier_set_nmethod();
2823   bs_nm->disarm(this);
2824 
2825   // There's an assumption made that this function is not used by GCs that
2826   // relocate objects, and therefore we don't call fix_oop_relocations.
2827 }
2828 
2829 nmethod* volatile nmethod::_oops_do_mark_nmethods;
2830 
2831 void nmethod::oops_do_log_change(const char* state) {
2832   LogTarget(Trace, gc, nmethod) lt;
2833   if (lt.is_enabled()) {
2834     LogStream ls(lt);
2835     CompileTask::print(&ls, this, state, true /* short_form */);
2836   }
2837 }
2838 
2839 bool nmethod::oops_do_try_claim() {
2840   if (oops_do_try_claim_weak_request()) {
2841     nmethod* result = oops_do_try_add_to_list_as_weak_done();
2842     assert(result == nullptr, "adding to global list as weak done must always succeed.");
2843     return true;
2844   }
2845   return false;
2846 }
2847 
2848 bool nmethod::oops_do_try_claim_weak_request() {
2849   assert(SafepointSynchronize::is_at_safepoint(), "only at safepoint");
2850 
2851   if ((_oops_do_mark_link == nullptr) &&
2852       (AtomicAccess::replace_if_null(&_oops_do_mark_link, mark_link(this, claim_weak_request_tag)))) {
2853     oops_do_log_change("oops_do, mark weak request");
2854     return true;
2855   }
2856   return false;
2857 }
2858 
2859 void nmethod::oops_do_set_strong_done(nmethod* old_head) {
2860   _oops_do_mark_link = mark_link(old_head, claim_strong_done_tag);
2861 }
2862 
2863 nmethod::oops_do_mark_link* nmethod::oops_do_try_claim_strong_done() {
2864   assert(SafepointSynchronize::is_at_safepoint(), "only at safepoint");
2865 
2866   oops_do_mark_link* old_next = AtomicAccess::cmpxchg(&_oops_do_mark_link, mark_link(nullptr, claim_weak_request_tag), mark_link(this, claim_strong_done_tag));
2867   if (old_next == nullptr) {
2868     oops_do_log_change("oops_do, mark strong done");
2869   }
2870   return old_next;
2871 }
2872 
2873 nmethod::oops_do_mark_link* nmethod::oops_do_try_add_strong_request(nmethod::oops_do_mark_link* next) {
2874   assert(SafepointSynchronize::is_at_safepoint(), "only at safepoint");
2875   assert(next == mark_link(this, claim_weak_request_tag), "Should be claimed as weak");
2876 
2877   oops_do_mark_link* old_next = AtomicAccess::cmpxchg(&_oops_do_mark_link, next, mark_link(this, claim_strong_request_tag));
2878   if (old_next == next) {
2879     oops_do_log_change("oops_do, mark strong request");
2880   }
2881   return old_next;
2882 }
2883 
2884 bool nmethod::oops_do_try_claim_weak_done_as_strong_done(nmethod::oops_do_mark_link* next) {
2885   assert(SafepointSynchronize::is_at_safepoint(), "only at safepoint");
2886   assert(extract_state(next) == claim_weak_done_tag, "Should be claimed as weak done");
2887 
2888   oops_do_mark_link* old_next = AtomicAccess::cmpxchg(&_oops_do_mark_link, next, mark_link(extract_nmethod(next), claim_strong_done_tag));
2889   if (old_next == next) {
2890     oops_do_log_change("oops_do, mark weak done -> mark strong done");
2891     return true;
2892   }
2893   return false;
2894 }
2895 
2896 nmethod* nmethod::oops_do_try_add_to_list_as_weak_done() {
2897   assert(SafepointSynchronize::is_at_safepoint(), "only at safepoint");
2898 
2899   assert(extract_state(_oops_do_mark_link) == claim_weak_request_tag ||
2900          extract_state(_oops_do_mark_link) == claim_strong_request_tag,
2901          "must be but is nmethod " PTR_FORMAT " %u", p2i(extract_nmethod(_oops_do_mark_link)), extract_state(_oops_do_mark_link));
2902 
2903   nmethod* old_head = AtomicAccess::xchg(&_oops_do_mark_nmethods, this);
2904   // Self-loop if needed.
2905   if (old_head == nullptr) {
2906     old_head = this;
2907   }
2908   // Try to install end of list and weak done tag.
2909   if (AtomicAccess::cmpxchg(&_oops_do_mark_link, mark_link(this, claim_weak_request_tag), mark_link(old_head, claim_weak_done_tag)) == mark_link(this, claim_weak_request_tag)) {
2910     oops_do_log_change("oops_do, mark weak done");
2911     return nullptr;
2912   } else {
2913     return old_head;
2914   }
2915 }
2916 
2917 void nmethod::oops_do_add_to_list_as_strong_done() {
2918   assert(SafepointSynchronize::is_at_safepoint(), "only at safepoint");
2919 
2920   nmethod* old_head = AtomicAccess::xchg(&_oops_do_mark_nmethods, this);
2921   // Self-loop if needed.
2922   if (old_head == nullptr) {
2923     old_head = this;
2924   }
2925   assert(_oops_do_mark_link == mark_link(this, claim_strong_done_tag), "must be but is nmethod " PTR_FORMAT " state %u",
2926          p2i(extract_nmethod(_oops_do_mark_link)), extract_state(_oops_do_mark_link));
2927 
2928   oops_do_set_strong_done(old_head);
2929 }
2930 
2931 void nmethod::oops_do_process_weak(OopsDoProcessor* p) {
2932   if (!oops_do_try_claim_weak_request()) {
2933     // Failed to claim for weak processing.
2934     oops_do_log_change("oops_do, mark weak request fail");
2935     return;
2936   }
2937 
2938   p->do_regular_processing(this);
2939 
2940   nmethod* old_head = oops_do_try_add_to_list_as_weak_done();
2941   if (old_head == nullptr) {
2942     return;
2943   }
2944   oops_do_log_change("oops_do, mark weak done fail");
2945   // Adding to global list failed, another thread added a strong request.
2946   assert(extract_state(_oops_do_mark_link) == claim_strong_request_tag,
2947          "must be but is %u", extract_state(_oops_do_mark_link));
2948 
2949   oops_do_log_change("oops_do, mark weak request -> mark strong done");
2950 
2951   oops_do_set_strong_done(old_head);
2952   // Do missing strong processing.
2953   p->do_remaining_strong_processing(this);
2954 }
2955 
2956 void nmethod::oops_do_process_strong(OopsDoProcessor* p) {
2957   oops_do_mark_link* next_raw = oops_do_try_claim_strong_done();
2958   if (next_raw == nullptr) {
2959     p->do_regular_processing(this);
2960     oops_do_add_to_list_as_strong_done();
2961     return;
2962   }
2963   // Claim failed. Figure out why and handle it.
2964   if (oops_do_has_weak_request(next_raw)) {
2965     oops_do_mark_link* old = next_raw;
2966     // Claim failed because being weak processed (state == "weak request").
2967     // Try to request deferred strong processing.
2968     next_raw = oops_do_try_add_strong_request(old);
2969     if (next_raw == old) {
2970       // Successfully requested deferred strong processing.
2971       return;
2972     }
2973     // Failed because of a concurrent transition. No longer in "weak request" state.
2974   }
2975   if (oops_do_has_any_strong_state(next_raw)) {
2976     // Already claimed for strong processing or requested for such.
2977     return;
2978   }
2979   if (oops_do_try_claim_weak_done_as_strong_done(next_raw)) {
2980     // Successfully claimed "weak done" as "strong done". Do the missing marking.
2981     p->do_remaining_strong_processing(this);
2982     return;
2983   }
2984   // Claim failed, some other thread got it.
2985 }
2986 
2987 void nmethod::oops_do_marking_prologue() {
2988   assert_at_safepoint();
2989 
2990   log_trace(gc, nmethod)("oops_do_marking_prologue");
2991   assert(_oops_do_mark_nmethods == nullptr, "must be empty");
2992 }
2993 
2994 void nmethod::oops_do_marking_epilogue() {
2995   assert_at_safepoint();
2996 
2997   nmethod* next = _oops_do_mark_nmethods;
2998   _oops_do_mark_nmethods = nullptr;
2999   if (next != nullptr) {
3000     nmethod* cur;
3001     do {
3002       cur = next;
3003       next = extract_nmethod(cur->_oops_do_mark_link);
3004       cur->_oops_do_mark_link = nullptr;
3005       DEBUG_ONLY(cur->verify_oop_relocations());
3006 
3007       LogTarget(Trace, gc, nmethod) lt;
3008       if (lt.is_enabled()) {
3009         LogStream ls(lt);
3010         CompileTask::print(&ls, cur, "oops_do, unmark", /*short_form:*/ true);
3011       }
3012       // End if self-loop has been detected.
3013     } while (cur != next);
3014   }
3015   log_trace(gc, nmethod)("oops_do_marking_epilogue");
3016 }
3017 
3018 inline bool includes(void* p, void* from, void* to) {
3019   return from <= p && p < to;
3020 }
3021 
3022 
3023 void nmethod::copy_scopes_pcs(PcDesc* pcs, int count) {
3024   assert(count >= 2, "must be sentinel values, at least");
3025 
3026 #ifdef ASSERT
3027   // must be sorted and unique; we do a binary search in find_pc_desc()
3028   int prev_offset = pcs[0].pc_offset();
3029   assert(prev_offset == PcDesc::lower_offset_limit,
3030          "must start with a sentinel");
3031   for (int i = 1; i < count; i++) {
3032     int this_offset = pcs[i].pc_offset();
3033     assert(this_offset > prev_offset, "offsets must be sorted");
3034     prev_offset = this_offset;
3035   }
3036   assert(prev_offset == PcDesc::upper_offset_limit,
3037          "must end with a sentinel");
3038 #endif //ASSERT
3039 
3040   int size = count * sizeof(PcDesc);
3041   assert(scopes_pcs_size() >= size, "oob");
3042   memcpy(scopes_pcs_begin(), pcs, size);
3043 
3044   // Adjust the final sentinel downward.
3045   PcDesc* last_pc = &scopes_pcs_begin()[count-1];
3046   assert(last_pc->pc_offset() == PcDesc::upper_offset_limit, "sanity");
3047   last_pc->set_pc_offset(content_size() + 1);
3048   for (; last_pc + 1 < scopes_pcs_end(); last_pc += 1) {
3049     // Fill any rounding gaps with copies of the last record.
3050     last_pc[1] = last_pc[0];
3051   }
3052   // The following assert could fail if sizeof(PcDesc) is not
3053   // an integral multiple of oopSize (the rounding term).
3054   // If it fails, change the logic to always allocate a multiple
3055   // of sizeof(PcDesc), and fill unused words with copies of *last_pc.
3056   assert(last_pc + 1 == scopes_pcs_end(), "must match exactly");
3057 }
3058 
3059 void nmethod::copy_scopes_data(u_char* buffer, int size) {
3060   assert(scopes_data_size() >= size, "oob");
3061   memcpy(scopes_data_begin(), buffer, size);
3062 }
3063 
3064 #ifdef ASSERT
3065 static PcDesc* linear_search(int pc_offset, bool approximate, PcDesc* lower, PcDesc* upper) {
3066   PcDesc* res = nullptr;
3067   assert(lower != nullptr && lower->pc_offset() == PcDesc::lower_offset_limit,
3068          "must start with a sentinel");
3069   // lower + 1 to exclude initial sentinel
3070   for (PcDesc* p = lower + 1; p < upper; p++) {
3071     NOT_PRODUCT(--pc_nmethod_stats.pc_desc_tests);  // don't count this call to match_desc
3072     if (match_desc(p, pc_offset, approximate)) {
3073       if (res == nullptr) {
3074         res = p;
3075       } else {
3076         res = (PcDesc*) badAddress;
3077       }
3078     }
3079   }
3080   return res;
3081 }
3082 #endif
3083 
3084 
3085 #ifndef PRODUCT
3086 // Version of method to collect statistic
3087 PcDesc* PcDescContainer::find_pc_desc(address pc, bool approximate, address code_begin,
3088                                       PcDesc* lower, PcDesc* upper) {
3089   ++pc_nmethod_stats.pc_desc_queries;
3090   if (approximate) ++pc_nmethod_stats.pc_desc_approx;
3091 
3092   PcDesc* desc = _pc_desc_cache.last_pc_desc();
3093   assert(desc != nullptr, "PcDesc cache should be initialized already");
3094   if (desc->pc_offset() == (pc - code_begin)) {
3095     // Cached value matched
3096     ++pc_nmethod_stats.pc_desc_tests;
3097     ++pc_nmethod_stats.pc_desc_repeats;
3098     return desc;
3099   }
3100   return find_pc_desc_internal(pc, approximate, code_begin, lower, upper);
3101 }
3102 #endif
3103 
3104 // Finds a PcDesc with real-pc equal to "pc"
3105 PcDesc* PcDescContainer::find_pc_desc_internal(address pc, bool approximate, address code_begin,
3106                                                PcDesc* lower_incl, PcDesc* upper_incl) {
3107   if ((pc < code_begin) ||
3108       (pc - code_begin) >= (ptrdiff_t) PcDesc::upper_offset_limit) {
3109     return nullptr;  // PC is wildly out of range
3110   }
3111   int pc_offset = (int) (pc - code_begin);
3112 
3113   // Check the PcDesc cache if it contains the desired PcDesc
3114   // (This as an almost 100% hit rate.)
3115   PcDesc* res = _pc_desc_cache.find_pc_desc(pc_offset, approximate);
3116   if (res != nullptr) {
3117     assert(res == linear_search(pc_offset, approximate, lower_incl, upper_incl), "cache ok");
3118     return res;
3119   }
3120 
3121   // Fallback algorithm: quasi-linear search for the PcDesc
3122   // Find the last pc_offset less than the given offset.
3123   // The successor must be the required match, if there is a match at all.
3124   // (Use a fixed radix to avoid expensive affine pointer arithmetic.)
3125   PcDesc* lower = lower_incl;     // this is initial sentinel
3126   PcDesc* upper = upper_incl - 1; // exclude final sentinel
3127   if (lower >= upper)  return nullptr;  // no PcDescs at all
3128 
3129 #define assert_LU_OK \
3130   /* invariant on lower..upper during the following search: */ \
3131   assert(lower->pc_offset() <  pc_offset, "sanity"); \
3132   assert(upper->pc_offset() >= pc_offset, "sanity")
3133   assert_LU_OK;
3134 
3135   // Use the last successful return as a split point.
3136   PcDesc* mid = _pc_desc_cache.last_pc_desc();
3137   NOT_PRODUCT(++pc_nmethod_stats.pc_desc_searches);
3138   if (mid->pc_offset() < pc_offset) {
3139     lower = mid;
3140   } else {
3141     upper = mid;
3142   }
3143 
3144   // Take giant steps at first (4096, then 256, then 16, then 1)
3145   const int LOG2_RADIX = 4 /*smaller steps in debug mode:*/ DEBUG_ONLY(-1);
3146   const int RADIX = (1 << LOG2_RADIX);
3147   for (int step = (1 << (LOG2_RADIX*3)); step > 1; step >>= LOG2_RADIX) {
3148     while ((mid = lower + step) < upper) {
3149       assert_LU_OK;
3150       NOT_PRODUCT(++pc_nmethod_stats.pc_desc_searches);
3151       if (mid->pc_offset() < pc_offset) {
3152         lower = mid;
3153       } else {
3154         upper = mid;
3155         break;
3156       }
3157     }
3158     assert_LU_OK;
3159   }
3160 
3161   // Sneak up on the value with a linear search of length ~16.
3162   while (true) {
3163     assert_LU_OK;
3164     mid = lower + 1;
3165     NOT_PRODUCT(++pc_nmethod_stats.pc_desc_searches);
3166     if (mid->pc_offset() < pc_offset) {
3167       lower = mid;
3168     } else {
3169       upper = mid;
3170       break;
3171     }
3172   }
3173 #undef assert_LU_OK
3174 
3175   if (match_desc(upper, pc_offset, approximate)) {
3176     assert(upper == linear_search(pc_offset, approximate, lower_incl, upper_incl), "search mismatch");
3177     if (!Thread::current_in_asgct()) {
3178       // we don't want to modify the cache if we're in ASGCT
3179       // which is typically called in a signal handler
3180       _pc_desc_cache.add_pc_desc(upper);
3181     }
3182     return upper;
3183   } else {
3184     assert(nullptr == linear_search(pc_offset, approximate, lower_incl, upper_incl), "search mismatch");
3185     return nullptr;
3186   }
3187 }
3188 
3189 bool nmethod::check_dependency_on(DepChange& changes) {
3190   // What has happened:
3191   // 1) a new class dependee has been added
3192   // 2) dependee and all its super classes have been marked
3193   bool found_check = false;  // set true if we are upset
3194   for (Dependencies::DepStream deps(this); deps.next(); ) {
3195     // Evaluate only relevant dependencies.
3196     if (deps.spot_check_dependency_at(changes) != nullptr) {
3197       found_check = true;
3198       NOT_DEBUG(break);
3199     }
3200   }
3201   return found_check;
3202 }
3203 
3204 // Called from mark_for_deoptimization, when dependee is invalidated.
3205 bool nmethod::is_dependent_on_method(Method* dependee) {
3206   for (Dependencies::DepStream deps(this); deps.next(); ) {
3207     if (deps.type() != Dependencies::evol_method)
3208       continue;
3209     Method* method = deps.method_argument(0);
3210     if (method == dependee) return true;
3211   }
3212   return false;
3213 }
3214 
3215 void nmethod_init() {
3216   // make sure you didn't forget to adjust the filler fields
3217   assert(sizeof(nmethod) % oopSize == 0, "nmethod size must be multiple of a word");
3218 }
3219 
3220 // -----------------------------------------------------------------------------
3221 // Verification
3222 
3223 class VerifyOopsClosure: public OopClosure {
3224   nmethod* _nm;
3225   bool     _ok;
3226 public:
3227   VerifyOopsClosure(nmethod* nm) : _nm(nm), _ok(true) { }
3228   bool ok() { return _ok; }
3229   virtual void do_oop(oop* p) {
3230     if (oopDesc::is_oop_or_null(*p)) return;
3231     // Print diagnostic information before calling print_nmethod().
3232     // Assertions therein might prevent call from returning.
3233     tty->print_cr("*** non-oop " PTR_FORMAT " found at " PTR_FORMAT " (offset %d)",
3234                   p2i(*p), p2i(p), (int)((intptr_t)p - (intptr_t)_nm));
3235     if (_ok) {
3236       _nm->print_nmethod(true);
3237       _ok = false;
3238     }
3239   }
3240   virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
3241 };
3242 
3243 class VerifyMetadataClosure: public MetadataClosure {
3244  public:
3245   void do_metadata(Metadata* md) {
3246     if (md->is_method()) {
3247       Method* method = (Method*)md;
3248       assert(!method->is_old(), "Should not be installing old methods");
3249     }
3250   }
3251 };
3252 
3253 
3254 void nmethod::verify() {
3255   if (is_not_entrant())
3256     return;
3257 
3258   // assert(oopDesc::is_oop(method()), "must be valid");
3259 
3260   ResourceMark rm;
3261 
3262   if (!CodeCache::contains(this)) {
3263     fatal("nmethod at " INTPTR_FORMAT " not in zone", p2i(this));
3264   }
3265 
3266   if(is_native_method() )
3267     return;
3268 
3269   nmethod* nm = CodeCache::find_nmethod(verified_entry_point());
3270   if (nm != this) {
3271     fatal("find_nmethod did not find this nmethod (" INTPTR_FORMAT ")", p2i(this));
3272   }
3273 
3274   for (PcDesc* p = scopes_pcs_begin(); p < scopes_pcs_end(); p++) {
3275     if (! p->verify(this)) {
3276       tty->print_cr("\t\tin nmethod at " INTPTR_FORMAT " (pcs)", p2i(this));
3277     }
3278   }
3279 
3280 #ifdef ASSERT
3281 #if INCLUDE_JVMCI
3282   {
3283     // Verify that implicit exceptions that deoptimize have a PcDesc and OopMap
3284     ImmutableOopMapSet* oms = oop_maps();
3285     ImplicitExceptionTable implicit_table(this);
3286     for (uint i = 0; i < implicit_table.len(); i++) {
3287       int exec_offset = (int) implicit_table.get_exec_offset(i);
3288       if (implicit_table.get_exec_offset(i) == implicit_table.get_cont_offset(i)) {
3289         assert(pc_desc_at(code_begin() + exec_offset) != nullptr, "missing PcDesc");
3290         bool found = false;
3291         for (int i = 0, imax = oms->count(); i < imax; i++) {
3292           if (oms->pair_at(i)->pc_offset() == exec_offset) {
3293             found = true;
3294             break;
3295           }
3296         }
3297         assert(found, "missing oopmap");
3298       }
3299     }
3300   }
3301 #endif
3302 #endif
3303 
3304   VerifyOopsClosure voc(this);
3305   oops_do(&voc);
3306   assert(voc.ok(), "embedded oops must be OK");
3307   Universe::heap()->verify_nmethod(this);
3308 
3309   assert(_oops_do_mark_link == nullptr, "_oops_do_mark_link for %s should be nullptr but is " PTR_FORMAT,
3310          nm->method()->external_name(), p2i(_oops_do_mark_link));
3311   verify_scopes();
3312 
3313   CompiledICLocker nm_verify(this);
3314   VerifyMetadataClosure vmc;
3315   metadata_do(&vmc);
3316 }
3317 
3318 
3319 void nmethod::verify_interrupt_point(address call_site, bool is_inline_cache) {
3320 
3321   // Verify IC only when nmethod installation is finished.
3322   if (!is_not_installed()) {
3323     if (CompiledICLocker::is_safe(this)) {
3324       if (is_inline_cache) {
3325         CompiledIC_at(this, call_site);
3326       } else {
3327         CompiledDirectCall::at(call_site);
3328       }
3329     } else {
3330       CompiledICLocker ml_verify(this);
3331       if (is_inline_cache) {
3332         CompiledIC_at(this, call_site);
3333       } else {
3334         CompiledDirectCall::at(call_site);
3335       }
3336     }
3337   }
3338 
3339   HandleMark hm(Thread::current());
3340 
3341   PcDesc* pd = pc_desc_at(nativeCall_at(call_site)->return_address());
3342   assert(pd != nullptr, "PcDesc must exist");
3343   for (ScopeDesc* sd = new ScopeDesc(this, pd);
3344        !sd->is_top(); sd = sd->sender()) {
3345     sd->verify();
3346   }
3347 }
3348 
3349 void nmethod::verify_scopes() {
3350   if( !method() ) return;       // Runtime stubs have no scope
3351   if (method()->is_native()) return; // Ignore stub methods.
3352   // iterate through all interrupt point
3353   // and verify the debug information is valid.
3354   RelocIterator iter(this);
3355   while (iter.next()) {
3356     address stub = nullptr;
3357     switch (iter.type()) {
3358       case relocInfo::virtual_call_type:
3359         verify_interrupt_point(iter.addr(), true /* is_inline_cache */);
3360         break;
3361       case relocInfo::opt_virtual_call_type:
3362         stub = iter.opt_virtual_call_reloc()->static_stub();
3363         verify_interrupt_point(iter.addr(), false /* is_inline_cache */);
3364         break;
3365       case relocInfo::static_call_type:
3366         stub = iter.static_call_reloc()->static_stub();
3367         verify_interrupt_point(iter.addr(), false /* is_inline_cache */);
3368         break;
3369       case relocInfo::runtime_call_type:
3370       case relocInfo::runtime_call_w_cp_type: {
3371         address destination = iter.reloc()->value();
3372         // Right now there is no way to find out which entries support
3373         // an interrupt point.  It would be nice if we had this
3374         // information in a table.
3375         break;
3376       }
3377       default:
3378         break;
3379     }
3380     assert(stub == nullptr || stub_contains(stub), "static call stub outside stub section");
3381   }
3382 }
3383 
3384 
3385 // -----------------------------------------------------------------------------
3386 // Printing operations
3387 
3388 void nmethod::print_on_impl(outputStream* st) const {
3389   ResourceMark rm;
3390 
3391   st->print("Compiled method ");
3392 
3393   if (is_compiled_by_c1()) {
3394     st->print("(c1) ");
3395   } else if (is_compiled_by_c2()) {
3396     st->print("(c2) ");
3397   } else if (is_compiled_by_jvmci()) {
3398     st->print("(JVMCI) ");
3399   } else {
3400     st->print("(n/a) ");
3401   }
3402 
3403   print_on_with_msg(st, nullptr);
3404 
3405   if (WizardMode) {
3406     st->print("((nmethod*) " INTPTR_FORMAT ") ", p2i(this));
3407     st->print(" for method " INTPTR_FORMAT , p2i(method()));
3408     st->print(" { ");
3409     st->print_cr("%s ", state());
3410     st->print_cr("}:");
3411   }
3412   if (size              () > 0) st->print_cr(" total in heap  [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
3413                                              p2i(this),
3414                                              p2i(this) + size(),
3415                                              size());
3416   if (consts_size       () > 0) st->print_cr(" constants      [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
3417                                              p2i(consts_begin()),
3418                                              p2i(consts_end()),
3419                                              consts_size());
3420   if (insts_size        () > 0) st->print_cr(" main code      [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
3421                                              p2i(insts_begin()),
3422                                              p2i(insts_end()),
3423                                              insts_size());
3424   if (stub_size         () > 0) st->print_cr(" stub code      [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
3425                                              p2i(stub_begin()),
3426                                              p2i(stub_end()),
3427                                              stub_size());
3428   if (oops_size         () > 0) st->print_cr(" oops           [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
3429                                              p2i(oops_begin()),
3430                                              p2i(oops_end()),
3431                                              oops_size());
3432   if (mutable_data_size() > 0) st->print_cr(" mutable data [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
3433                                              p2i(mutable_data_begin()),
3434                                              p2i(mutable_data_end()),
3435                                              mutable_data_size());
3436   if (relocation_size() > 0)   st->print_cr(" relocation     [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
3437                                              p2i(relocation_begin()),
3438                                              p2i(relocation_end()),
3439                                              relocation_size());
3440   if (metadata_size     () > 0) st->print_cr(" metadata       [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
3441                                              p2i(metadata_begin()),
3442                                              p2i(metadata_end()),
3443                                              metadata_size());
3444 #if INCLUDE_JVMCI
3445   if (jvmci_data_size   () > 0) st->print_cr(" JVMCI data     [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
3446                                              p2i(jvmci_data_begin()),
3447                                              p2i(jvmci_data_end()),
3448                                              jvmci_data_size());
3449 #endif
3450   if (immutable_data_size() > 0) st->print_cr(" immutable data [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
3451                                              p2i(immutable_data_begin()),
3452                                              p2i(immutable_data_end()),
3453                                              immutable_data_size());
3454   if (dependencies_size () > 0) st->print_cr(" dependencies   [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
3455                                              p2i(dependencies_begin()),
3456                                              p2i(dependencies_end()),
3457                                              dependencies_size());
3458   if (nul_chk_table_size() > 0) st->print_cr(" nul chk table  [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
3459                                              p2i(nul_chk_table_begin()),
3460                                              p2i(nul_chk_table_end()),
3461                                              nul_chk_table_size());
3462   if (handler_table_size() > 0) st->print_cr(" handler table  [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
3463                                              p2i(handler_table_begin()),
3464                                              p2i(handler_table_end()),
3465                                              handler_table_size());
3466   if (scopes_pcs_size   () > 0) st->print_cr(" scopes pcs     [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
3467                                              p2i(scopes_pcs_begin()),
3468                                              p2i(scopes_pcs_end()),
3469                                              scopes_pcs_size());
3470   if (scopes_data_size  () > 0) st->print_cr(" scopes data    [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
3471                                              p2i(scopes_data_begin()),
3472                                              p2i(scopes_data_end()),
3473                                              scopes_data_size());
3474 #if INCLUDE_JVMCI
3475   if (speculations_size () > 0) st->print_cr(" speculations   [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
3476                                              p2i(speculations_begin()),
3477                                              p2i(speculations_end()),
3478                                              speculations_size());
3479 #endif
3480 }
3481 
3482 void nmethod::print_code() {
3483   ResourceMark m;
3484   ttyLocker ttyl;
3485   // Call the specialized decode method of this class.
3486   decode(tty);
3487 }
3488 
3489 #ifndef PRODUCT  // called InstanceKlass methods are available only then. Declared as PRODUCT_RETURN
3490 
3491 void nmethod::print_dependencies_on(outputStream* out) {
3492   ResourceMark rm;
3493   stringStream st;
3494   st.print_cr("Dependencies:");
3495   for (Dependencies::DepStream deps(this); deps.next(); ) {
3496     deps.print_dependency(&st);
3497     InstanceKlass* ctxk = deps.context_type();
3498     if (ctxk != nullptr) {
3499       if (ctxk->is_dependent_nmethod(this)) {
3500         st.print_cr("   [nmethod<=klass]%s", ctxk->external_name());
3501       }
3502     }
3503     deps.log_dependency();  // put it into the xml log also
3504   }
3505   out->print_raw(st.as_string());
3506 }
3507 #endif
3508 
3509 #if defined(SUPPORT_DATA_STRUCTS)
3510 
3511 // Print the oops from the underlying CodeBlob.
3512 void nmethod::print_oops(outputStream* st) {
3513   ResourceMark m;
3514   st->print("Oops:");
3515   if (oops_begin() < oops_end()) {
3516     st->cr();
3517     for (oop* p = oops_begin(); p < oops_end(); p++) {
3518       Disassembler::print_location((unsigned char*)p, (unsigned char*)oops_begin(), (unsigned char*)oops_end(), st, true, false);
3519       st->print(PTR_FORMAT " ", *((uintptr_t*)p));
3520       if (Universe::contains_non_oop_word(p)) {
3521         st->print_cr("NON_OOP");
3522         continue;  // skip non-oops
3523       }
3524       if (*p == nullptr) {
3525         st->print_cr("nullptr-oop");
3526         continue;  // skip non-oops
3527       }
3528       (*p)->print_value_on(st);
3529       st->cr();
3530     }
3531   } else {
3532     st->print_cr(" <list empty>");
3533   }
3534 }
3535 
3536 // Print metadata pool.
3537 void nmethod::print_metadata(outputStream* st) {
3538   ResourceMark m;
3539   st->print("Metadata:");
3540   if (metadata_begin() < metadata_end()) {
3541     st->cr();
3542     for (Metadata** p = metadata_begin(); p < metadata_end(); p++) {
3543       Disassembler::print_location((unsigned char*)p, (unsigned char*)metadata_begin(), (unsigned char*)metadata_end(), st, true, false);
3544       st->print(PTR_FORMAT " ", *((uintptr_t*)p));
3545       if (*p && *p != Universe::non_oop_word()) {
3546         (*p)->print_value_on(st);
3547       }
3548       st->cr();
3549     }
3550   } else {
3551     st->print_cr(" <list empty>");
3552   }
3553 }
3554 
3555 #ifndef PRODUCT  // ScopeDesc::print_on() is available only then. Declared as PRODUCT_RETURN
3556 void nmethod::print_scopes_on(outputStream* st) {
3557   // Find the first pc desc for all scopes in the code and print it.
3558   ResourceMark rm;
3559   st->print("scopes:");
3560   if (scopes_pcs_begin() < scopes_pcs_end()) {
3561     st->cr();
3562     for (PcDesc* p = scopes_pcs_begin(); p < scopes_pcs_end(); p++) {
3563       if (p->scope_decode_offset() == DebugInformationRecorder::serialized_null)
3564         continue;
3565 
3566       ScopeDesc* sd = scope_desc_at(p->real_pc(this));
3567       while (sd != nullptr) {
3568         sd->print_on(st, p);  // print output ends with a newline
3569         sd = sd->sender();
3570       }
3571     }
3572   } else {
3573     st->print_cr(" <list empty>");
3574   }
3575 }
3576 #endif
3577 
3578 #ifndef PRODUCT  // RelocIterator does support printing only then.
3579 void nmethod::print_relocations() {
3580   ResourceMark m;       // in case methods get printed via the debugger
3581   tty->print_cr("relocations:");
3582   RelocIterator iter(this);
3583   iter.print_on(tty);
3584 }
3585 #endif
3586 
3587 void nmethod::print_pcs_on(outputStream* st) {
3588   ResourceMark m;       // in case methods get printed via debugger
3589   st->print("pc-bytecode offsets:");
3590   if (scopes_pcs_begin() < scopes_pcs_end()) {
3591     st->cr();
3592     for (PcDesc* p = scopes_pcs_begin(); p < scopes_pcs_end(); p++) {
3593       p->print_on(st, this);  // print output ends with a newline
3594     }
3595   } else {
3596     st->print_cr(" <list empty>");
3597   }
3598 }
3599 
3600 void nmethod::print_handler_table() {
3601   ExceptionHandlerTable(this).print(code_begin());
3602 }
3603 
3604 void nmethod::print_nul_chk_table() {
3605   ImplicitExceptionTable(this).print(code_begin());
3606 }
3607 
3608 void nmethod::print_recorded_oop(int log_n, int i) {
3609   void* value;
3610 
3611   if (i == 0) {
3612     value = nullptr;
3613   } else {
3614     // Be careful around non-oop words. Don't create an oop
3615     // with that value, or it will assert in verification code.
3616     if (Universe::contains_non_oop_word(oop_addr_at(i))) {
3617       value = Universe::non_oop_word();
3618     } else {
3619       value = oop_at(i);
3620     }
3621   }
3622 
3623   tty->print("#%*d: " INTPTR_FORMAT " ", log_n, i, p2i(value));
3624 
3625   if (value == Universe::non_oop_word()) {
3626     tty->print("non-oop word");
3627   } else {
3628     if (value == nullptr) {
3629       tty->print("nullptr-oop");
3630     } else {
3631       oop_at(i)->print_value_on(tty);
3632     }
3633   }
3634 
3635   tty->cr();
3636 }
3637 
3638 void nmethod::print_recorded_oops() {
3639   const int n = oops_count();
3640   const int log_n = (n<10) ? 1 : (n<100) ? 2 : (n<1000) ? 3 : (n<10000) ? 4 : 6;
3641   tty->print("Recorded oops:");
3642   if (n > 0) {
3643     tty->cr();
3644     for (int i = 0; i < n; i++) {
3645       print_recorded_oop(log_n, i);
3646     }
3647   } else {
3648     tty->print_cr(" <list empty>");
3649   }
3650 }
3651 
3652 void nmethod::print_recorded_metadata() {
3653   const int n = metadata_count();
3654   const int log_n = (n<10) ? 1 : (n<100) ? 2 : (n<1000) ? 3 : (n<10000) ? 4 : 6;
3655   tty->print("Recorded metadata:");
3656   if (n > 0) {
3657     tty->cr();
3658     for (int i = 0; i < n; i++) {
3659       Metadata* m = metadata_at(i);
3660       tty->print("#%*d: " INTPTR_FORMAT " ", log_n, i, p2i(m));
3661       if (m == (Metadata*)Universe::non_oop_word()) {
3662         tty->print("non-metadata word");
3663       } else if (m == nullptr) {
3664         tty->print("nullptr-oop");
3665       } else {
3666         Metadata::print_value_on_maybe_null(tty, m);
3667       }
3668       tty->cr();
3669     }
3670   } else {
3671     tty->print_cr(" <list empty>");
3672   }
3673 }
3674 #endif
3675 
3676 #if defined(SUPPORT_ASSEMBLY) || defined(SUPPORT_ABSTRACT_ASSEMBLY)
3677 
3678 void nmethod::print_constant_pool(outputStream* st) {
3679   //-----------------------------------
3680   //---<  Print the constant pool  >---
3681   //-----------------------------------
3682   int consts_size = this->consts_size();
3683   if ( consts_size > 0 ) {
3684     unsigned char* cstart = this->consts_begin();
3685     unsigned char* cp     = cstart;
3686     unsigned char* cend   = cp + consts_size;
3687     unsigned int   bytes_per_line = 4;
3688     unsigned int   CP_alignment   = 8;
3689     unsigned int   n;
3690 
3691     st->cr();
3692 
3693     //---<  print CP header to make clear what's printed  >---
3694     if( ((uintptr_t)cp&(CP_alignment-1)) == 0 ) {
3695       n = bytes_per_line;
3696       st->print_cr("[Constant Pool]");
3697       Disassembler::print_location(cp, cstart, cend, st, true, true);
3698       Disassembler::print_hexdata(cp, n, st, true);
3699       st->cr();
3700     } else {
3701       n = (int)((uintptr_t)cp & (bytes_per_line-1));
3702       st->print_cr("[Constant Pool (unaligned)]");
3703     }
3704 
3705     //---<  print CP contents, bytes_per_line at a time  >---
3706     while (cp < cend) {
3707       Disassembler::print_location(cp, cstart, cend, st, true, false);
3708       Disassembler::print_hexdata(cp, n, st, false);
3709       cp += n;
3710       n   = bytes_per_line;
3711       st->cr();
3712     }
3713 
3714     //---<  Show potential alignment gap between constant pool and code  >---
3715     cend = code_begin();
3716     if( cp < cend ) {
3717       n = 4;
3718       st->print_cr("[Code entry alignment]");
3719       while (cp < cend) {
3720         Disassembler::print_location(cp, cstart, cend, st, false, false);
3721         cp += n;
3722         st->cr();
3723       }
3724     }
3725   } else {
3726     st->print_cr("[Constant Pool (empty)]");
3727   }
3728   st->cr();
3729 }
3730 
3731 #endif
3732 
3733 // Disassemble this nmethod.
3734 // Print additional debug information, if requested. This could be code
3735 // comments, block comments, profiling counters, etc.
3736 // The undisassembled format is useful no disassembler library is available.
3737 // The resulting hex dump (with markers) can be disassembled later, or on
3738 // another system, when/where a disassembler library is available.
3739 void nmethod::decode2(outputStream* ost) const {
3740 
3741   // Called from frame::back_trace_with_decode without ResourceMark.
3742   ResourceMark rm;
3743 
3744   // Make sure we have a valid stream to print on.
3745   outputStream* st = ost ? ost : tty;
3746 
3747 #if defined(SUPPORT_ABSTRACT_ASSEMBLY) && ! defined(SUPPORT_ASSEMBLY)
3748   const bool use_compressed_format    = true;
3749   const bool compressed_with_comments = use_compressed_format && (AbstractDisassembler::show_comment() ||
3750                                                                   AbstractDisassembler::show_block_comment());
3751 #else
3752   const bool use_compressed_format    = Disassembler::is_abstract();
3753   const bool compressed_with_comments = use_compressed_format && (AbstractDisassembler::show_comment() ||
3754                                                                   AbstractDisassembler::show_block_comment());
3755 #endif
3756 
3757   st->cr();
3758   this->print_on(st);
3759   st->cr();
3760 
3761 #if defined(SUPPORT_ASSEMBLY)
3762   //----------------------------------
3763   //---<  Print real disassembly  >---
3764   //----------------------------------
3765   if (! use_compressed_format) {
3766     st->print_cr("[Disassembly]");
3767     Disassembler::decode(const_cast<nmethod*>(this), st);
3768     st->bol();
3769     st->print_cr("[/Disassembly]");
3770     return;
3771   }
3772 #endif
3773 
3774 #if defined(SUPPORT_ABSTRACT_ASSEMBLY)
3775 
3776   // Compressed undisassembled disassembly format.
3777   // The following status values are defined/supported:
3778   //   = 0 - currently at bol() position, nothing printed yet on current line.
3779   //   = 1 - currently at position after print_location().
3780   //   > 1 - in the midst of printing instruction stream bytes.
3781   int        compressed_format_idx    = 0;
3782   int        code_comment_column      = 0;
3783   const int  instr_maxlen             = Assembler::instr_maxlen();
3784   const uint tabspacing               = 8;
3785   unsigned char* start = this->code_begin();
3786   unsigned char* p     = this->code_begin();
3787   unsigned char* end   = this->code_end();
3788   unsigned char* pss   = p; // start of a code section (used for offsets)
3789 
3790   if ((start == nullptr) || (end == nullptr)) {
3791     st->print_cr("PrintAssembly not possible due to uninitialized section pointers");
3792     return;
3793   }
3794 #endif
3795 
3796 #if defined(SUPPORT_ABSTRACT_ASSEMBLY)
3797   //---<  plain abstract disassembly, no comments or anything, just section headers  >---
3798   if (use_compressed_format && ! compressed_with_comments) {
3799     const_cast<nmethod*>(this)->print_constant_pool(st);
3800 
3801     st->bol();
3802     st->cr();
3803     st->print_cr("Loading hsdis library failed, undisassembled code is shown in MachCode section");
3804     //---<  Open the output (Marker for post-mortem disassembler)  >---
3805     st->print_cr("[MachCode]");
3806     const char* header = nullptr;
3807     address p0 = p;
3808     while (p < end) {
3809       address pp = p;
3810       while ((p < end) && (header == nullptr)) {
3811         header = nmethod_section_label(p);
3812         pp  = p;
3813         p  += Assembler::instr_len(p);
3814       }
3815       if (pp > p0) {
3816         AbstractDisassembler::decode_range_abstract(p0, pp, start, end, st, Assembler::instr_maxlen());
3817         p0 = pp;
3818         p  = pp;
3819         header = nullptr;
3820       } else if (header != nullptr) {
3821         st->bol();
3822         st->print_cr("%s", header);
3823         header = nullptr;
3824       }
3825     }
3826     //---<  Close the output (Marker for post-mortem disassembler)  >---
3827     st->bol();
3828     st->print_cr("[/MachCode]");
3829     return;
3830   }
3831 #endif
3832 
3833 #if defined(SUPPORT_ABSTRACT_ASSEMBLY)
3834   //---<  abstract disassembly with comments and section headers merged in  >---
3835   if (compressed_with_comments) {
3836     const_cast<nmethod*>(this)->print_constant_pool(st);
3837 
3838     st->bol();
3839     st->cr();
3840     st->print_cr("Loading hsdis library failed, undisassembled code is shown in MachCode section");
3841     //---<  Open the output (Marker for post-mortem disassembler)  >---
3842     st->print_cr("[MachCode]");
3843     while ((p < end) && (p != nullptr)) {
3844       const int instruction_size_in_bytes = Assembler::instr_len(p);
3845 
3846       //---<  Block comments for nmethod. Interrupts instruction stream, if any.  >---
3847       // Outputs a bol() before and a cr() after, but only if a comment is printed.
3848       // Prints nmethod_section_label as well.
3849       if (AbstractDisassembler::show_block_comment()) {
3850         print_block_comment(st, p);
3851         if (st->position() == 0) {
3852           compressed_format_idx = 0;
3853         }
3854       }
3855 
3856       //---<  New location information after line break  >---
3857       if (compressed_format_idx == 0) {
3858         code_comment_column   = Disassembler::print_location(p, pss, end, st, false, false);
3859         compressed_format_idx = 1;
3860       }
3861 
3862       //---<  Code comment for current instruction. Address range [p..(p+len))  >---
3863       unsigned char* p_end = p + (ssize_t)instruction_size_in_bytes;
3864       S390_ONLY(if (p_end > end) p_end = end;) // avoid getting past the end
3865 
3866       if (AbstractDisassembler::show_comment() && const_cast<nmethod*>(this)->has_code_comment(p, p_end)) {
3867         //---<  interrupt instruction byte stream for code comment  >---
3868         if (compressed_format_idx > 1) {
3869           st->cr();  // interrupt byte stream
3870           st->cr();  // add an empty line
3871           code_comment_column = Disassembler::print_location(p, pss, end, st, false, false);
3872         }
3873         const_cast<nmethod*>(this)->print_code_comment_on(st, code_comment_column, p, p_end );
3874         st->bol();
3875         compressed_format_idx = 0;
3876       }
3877 
3878       //---<  New location information after line break  >---
3879       if (compressed_format_idx == 0) {
3880         code_comment_column   = Disassembler::print_location(p, pss, end, st, false, false);
3881         compressed_format_idx = 1;
3882       }
3883 
3884       //---<  Nicely align instructions for readability  >---
3885       if (compressed_format_idx > 1) {
3886         Disassembler::print_delimiter(st);
3887       }
3888 
3889       //---<  Now, finally, print the actual instruction bytes  >---
3890       unsigned char* p0 = p;
3891       p = Disassembler::decode_instruction_abstract(p, st, instruction_size_in_bytes, instr_maxlen);
3892       compressed_format_idx += (int)(p - p0);
3893 
3894       if (Disassembler::start_newline(compressed_format_idx-1)) {
3895         st->cr();
3896         compressed_format_idx = 0;
3897       }
3898     }
3899     //---<  Close the output (Marker for post-mortem disassembler)  >---
3900     st->bol();
3901     st->print_cr("[/MachCode]");
3902     return;
3903   }
3904 #endif
3905 }
3906 
3907 #if defined(SUPPORT_ASSEMBLY) || defined(SUPPORT_ABSTRACT_ASSEMBLY)
3908 
3909 const char* nmethod::reloc_string_for(u_char* begin, u_char* end) {
3910   RelocIterator iter(this, begin, end);
3911   bool have_one = false;
3912   while (iter.next()) {
3913     have_one = true;
3914     switch (iter.type()) {
3915         case relocInfo::none: {
3916           // Skip it and check next
3917           break;
3918         }
3919         case relocInfo::oop_type: {
3920           // Get a non-resizable resource-allocated stringStream.
3921           // Our callees make use of (nested) ResourceMarks.
3922           stringStream st(NEW_RESOURCE_ARRAY(char, 1024), 1024);
3923           oop_Relocation* r = iter.oop_reloc();
3924           oop obj = r->oop_value();
3925           st.print("oop(");
3926           if (obj == nullptr) st.print("nullptr");
3927           else obj->print_value_on(&st);
3928           st.print(")");
3929           return st.as_string();
3930         }
3931         case relocInfo::metadata_type: {
3932           stringStream st;
3933           metadata_Relocation* r = iter.metadata_reloc();
3934           Metadata* obj = r->metadata_value();
3935           st.print("metadata(");
3936           if (obj == nullptr) st.print("nullptr");
3937           else obj->print_value_on(&st);
3938           st.print(")");
3939           return st.as_string();
3940         }
3941         case relocInfo::runtime_call_type:
3942         case relocInfo::runtime_call_w_cp_type: {
3943           stringStream st;
3944           st.print("runtime_call");
3945           CallRelocation* r = (CallRelocation*)iter.reloc();
3946           address dest = r->destination();
3947           if (StubRoutines::contains(dest)) {
3948             StubCodeDesc* desc = StubCodeDesc::desc_for(dest);
3949             if (desc == nullptr) {
3950               desc = StubCodeDesc::desc_for(dest + frame::pc_return_offset);
3951             }
3952             if (desc != nullptr) {
3953               st.print(" Stub::%s", desc->name());
3954               return st.as_string();
3955             }
3956           }
3957           CodeBlob* cb = CodeCache::find_blob(dest);
3958           if (cb != nullptr) {
3959             st.print(" %s", cb->name());
3960           } else {
3961             ResourceMark rm;
3962             const int buflen = 1024;
3963             char* buf = NEW_RESOURCE_ARRAY(char, buflen);
3964             int offset;
3965             if (os::dll_address_to_function_name(dest, buf, buflen, &offset)) {
3966               st.print(" %s", buf);
3967               if (offset != 0) {
3968                 st.print("+%d", offset);
3969               }
3970             }
3971           }
3972           return st.as_string();
3973         }
3974         case relocInfo::virtual_call_type: {
3975           stringStream st;
3976           st.print_raw("virtual_call");
3977           virtual_call_Relocation* r = iter.virtual_call_reloc();
3978           Method* m = r->method_value();
3979           if (m != nullptr) {
3980             assert(m->is_method(), "");
3981             m->print_short_name(&st);
3982           }
3983           return st.as_string();
3984         }
3985         case relocInfo::opt_virtual_call_type: {
3986           stringStream st;
3987           st.print_raw("optimized virtual_call");
3988           opt_virtual_call_Relocation* r = iter.opt_virtual_call_reloc();
3989           Method* m = r->method_value();
3990           if (m != nullptr) {
3991             assert(m->is_method(), "");
3992             m->print_short_name(&st);
3993           }
3994           return st.as_string();
3995         }
3996         case relocInfo::static_call_type: {
3997           stringStream st;
3998           st.print_raw("static_call");
3999           static_call_Relocation* r = iter.static_call_reloc();
4000           Method* m = r->method_value();
4001           if (m != nullptr) {
4002             assert(m->is_method(), "");
4003             m->print_short_name(&st);
4004           }
4005           return st.as_string();
4006         }
4007         case relocInfo::static_stub_type:      return "static_stub";
4008         case relocInfo::external_word_type:    return "external_word";
4009         case relocInfo::internal_word_type:    return "internal_word";
4010         case relocInfo::section_word_type:     return "section_word";
4011         case relocInfo::poll_type:             return "poll";
4012         case relocInfo::poll_return_type:      return "poll_return";
4013         case relocInfo::trampoline_stub_type:  return "trampoline_stub";
4014         case relocInfo::entry_guard_type:      return "entry_guard";
4015         case relocInfo::post_call_nop_type:    return "post_call_nop";
4016         case relocInfo::barrier_type: {
4017           barrier_Relocation* const reloc = iter.barrier_reloc();
4018           stringStream st;
4019           st.print("barrier format=%d", reloc->format());
4020           return st.as_string();
4021         }
4022 
4023         case relocInfo::type_mask:             return "type_bit_mask";
4024 
4025         default: {
4026           stringStream st;
4027           st.print("unknown relocInfo=%d", (int) iter.type());
4028           return st.as_string();
4029         }
4030     }
4031   }
4032   return have_one ? "other" : nullptr;
4033 }
4034 
4035 // Return the last scope in (begin..end]
4036 ScopeDesc* nmethod::scope_desc_in(address begin, address end) {
4037   PcDesc* p = pc_desc_near(begin+1);
4038   if (p != nullptr && p->real_pc(this) <= end) {
4039     return new ScopeDesc(this, p);
4040   }
4041   return nullptr;
4042 }
4043 
4044 const char* nmethod::nmethod_section_label(address pos) const {
4045   const char* label = nullptr;
4046   if (pos == code_begin())                                              label = "[Instructions begin]";
4047   if (pos == entry_point())                                             label = "[Entry Point]";
4048   if (pos == verified_entry_point())                                    label = "[Verified Entry Point]";
4049   if (pos == consts_begin() && pos != insts_begin())                    label = "[Constants]";
4050   // Check stub_code before checking exception_handler or deopt_handler.
4051   if (pos == this->stub_begin())                                        label = "[Stub Code]";
4052   if (JVMCI_ONLY(_exception_offset >= 0 &&) pos == exception_begin())          label = "[Exception Handler]";
4053   if (JVMCI_ONLY(_deopt_handler_entry_offset != -1 &&) pos == deopt_handler_entry()) label = "[Deopt Handler Entry Point]";
4054   return label;
4055 }
4056 
4057 void nmethod::print_nmethod_labels(outputStream* stream, address block_begin, bool print_section_labels) const {
4058   if (print_section_labels) {
4059     const char* label = nmethod_section_label(block_begin);
4060     if (label != nullptr) {
4061       stream->bol();
4062       stream->print_cr("%s", label);
4063     }
4064   }
4065 
4066   if (block_begin == entry_point()) {
4067     Method* m = method();
4068     if (m != nullptr) {
4069       stream->print("  # ");
4070       m->print_value_on(stream);
4071       stream->cr();
4072     }
4073     if (m != nullptr && !is_osr_method()) {
4074       ResourceMark rm;
4075       int sizeargs = m->size_of_parameters();
4076       BasicType* sig_bt = NEW_RESOURCE_ARRAY(BasicType, sizeargs);
4077       VMRegPair* regs   = NEW_RESOURCE_ARRAY(VMRegPair, sizeargs);
4078       {
4079         int sig_index = 0;
4080         if (!m->is_static())
4081           sig_bt[sig_index++] = T_OBJECT; // 'this'
4082         for (SignatureStream ss(m->signature()); !ss.at_return_type(); ss.next()) {
4083           BasicType t = ss.type();
4084           sig_bt[sig_index++] = t;
4085           if (type2size[t] == 2) {
4086             sig_bt[sig_index++] = T_VOID;
4087           } else {
4088             assert(type2size[t] == 1, "size is 1 or 2");
4089           }
4090         }
4091         assert(sig_index == sizeargs, "");
4092       }
4093       const char* spname = "sp"; // make arch-specific?
4094       SharedRuntime::java_calling_convention(sig_bt, regs, sizeargs);
4095       int stack_slot_offset = this->frame_size() * wordSize;
4096       int tab1 = 14, tab2 = 24;
4097       int sig_index = 0;
4098       int arg_index = (m->is_static() ? 0 : -1);
4099       bool did_old_sp = false;
4100       for (SignatureStream ss(m->signature()); !ss.at_return_type(); ) {
4101         bool at_this = (arg_index == -1);
4102         bool at_old_sp = false;
4103         BasicType t = (at_this ? T_OBJECT : ss.type());
4104         assert(t == sig_bt[sig_index], "sigs in sync");
4105         if (at_this)
4106           stream->print("  # this: ");
4107         else
4108           stream->print("  # parm%d: ", arg_index);
4109         stream->move_to(tab1);
4110         VMReg fst = regs[sig_index].first();
4111         VMReg snd = regs[sig_index].second();
4112         if (fst->is_reg()) {
4113           stream->print("%s", fst->name());
4114           if (snd->is_valid())  {
4115             stream->print(":%s", snd->name());
4116           }
4117         } else if (fst->is_stack()) {
4118           int offset = fst->reg2stack() * VMRegImpl::stack_slot_size + stack_slot_offset;
4119           if (offset == stack_slot_offset)  at_old_sp = true;
4120           stream->print("[%s+0x%x]", spname, offset);
4121         } else {
4122           stream->print("reg%d:%d??", (int)(intptr_t)fst, (int)(intptr_t)snd);
4123         }
4124         stream->print(" ");
4125         stream->move_to(tab2);
4126         stream->print("= ");
4127         if (at_this) {
4128           m->method_holder()->print_value_on(stream);
4129         } else {
4130           bool did_name = false;
4131           if (!at_this && ss.is_reference()) {
4132             Symbol* name = ss.as_symbol();
4133             name->print_value_on(stream);
4134             did_name = true;
4135           }
4136           if (!did_name)
4137             stream->print("%s", type2name(t));
4138         }
4139         if (at_old_sp) {
4140           stream->print("  (%s of caller)", spname);
4141           did_old_sp = true;
4142         }
4143         stream->cr();
4144         sig_index += type2size[t];
4145         arg_index += 1;
4146         if (!at_this)  ss.next();
4147       }
4148       if (!did_old_sp) {
4149         stream->print("  # ");
4150         stream->move_to(tab1);
4151         stream->print("[%s+0x%x]", spname, stack_slot_offset);
4152         stream->print("  (%s of caller)", spname);
4153         stream->cr();
4154       }
4155     }
4156   }
4157 }
4158 
4159 // Returns whether this nmethod has code comments.
4160 bool nmethod::has_code_comment(address begin, address end) {
4161   // scopes?
4162   ScopeDesc* sd  = scope_desc_in(begin, end);
4163   if (sd != nullptr) return true;
4164 
4165   // relocations?
4166   const char* str = reloc_string_for(begin, end);
4167   if (str != nullptr) return true;
4168 
4169   // implicit exceptions?
4170   int cont_offset = ImplicitExceptionTable(this).continuation_offset((uint)(begin - code_begin()));
4171   if (cont_offset != 0) return true;
4172 
4173   return false;
4174 }
4175 
4176 void nmethod::print_code_comment_on(outputStream* st, int column, address begin, address end) {
4177   ImplicitExceptionTable implicit_table(this);
4178   int pc_offset = (int)(begin - code_begin());
4179   int cont_offset = implicit_table.continuation_offset(pc_offset);
4180   bool oop_map_required = false;
4181   if (cont_offset != 0) {
4182     st->move_to(column, 6, 0);
4183     if (pc_offset == cont_offset) {
4184       st->print("; implicit exception: deoptimizes");
4185       oop_map_required = true;
4186     } else {
4187       st->print("; implicit exception: dispatches to " INTPTR_FORMAT, p2i(code_begin() + cont_offset));
4188     }
4189   }
4190 
4191   // Find an oopmap in (begin, end].  We use the odd half-closed
4192   // interval so that oop maps and scope descs which are tied to the
4193   // byte after a call are printed with the call itself.  OopMaps
4194   // associated with implicit exceptions are printed with the implicit
4195   // instruction.
4196   address base = code_begin();
4197   ImmutableOopMapSet* oms = oop_maps();
4198   if (oms != nullptr) {
4199     for (int i = 0, imax = oms->count(); i < imax; i++) {
4200       const ImmutableOopMapPair* pair = oms->pair_at(i);
4201       const ImmutableOopMap* om = pair->get_from(oms);
4202       address pc = base + pair->pc_offset();
4203       if (pc >= begin) {
4204 #if INCLUDE_JVMCI
4205         bool is_implicit_deopt = implicit_table.continuation_offset(pair->pc_offset()) == (uint) pair->pc_offset();
4206 #else
4207         bool is_implicit_deopt = false;
4208 #endif
4209         if (is_implicit_deopt ? pc == begin : pc > begin && pc <= end) {
4210           st->move_to(column, 6, 0);
4211           st->print("; ");
4212           om->print_on(st);
4213           oop_map_required = false;
4214         }
4215       }
4216       if (pc > end) {
4217         break;
4218       }
4219     }
4220   }
4221   assert(!oop_map_required, "missed oopmap");
4222 
4223   Thread* thread = Thread::current();
4224 
4225   // Print any debug info present at this pc.
4226   ScopeDesc* sd  = scope_desc_in(begin, end);
4227   if (sd != nullptr) {
4228     st->move_to(column, 6, 0);
4229     if (sd->bci() == SynchronizationEntryBCI) {
4230       st->print(";*synchronization entry");
4231     } else if (sd->bci() == AfterBci) {
4232       st->print(";* method exit (unlocked if synchronized)");
4233     } else if (sd->bci() == UnwindBci) {
4234       st->print(";* unwind (locked if synchronized)");
4235     } else if (sd->bci() == AfterExceptionBci) {
4236       st->print(";* unwind (unlocked if synchronized)");
4237     } else if (sd->bci() == UnknownBci) {
4238       st->print(";* unknown");
4239     } else if (sd->bci() == InvalidFrameStateBci) {
4240       st->print(";* invalid frame state");
4241     } else {
4242       if (sd->method() == nullptr) {
4243         st->print("method is nullptr");
4244       } else if (sd->method()->is_native()) {
4245         st->print("method is native");
4246       } else {
4247         Bytecodes::Code bc = sd->method()->java_code_at(sd->bci());
4248         st->print(";*%s", Bytecodes::name(bc));
4249         switch (bc) {
4250         case Bytecodes::_invokevirtual:
4251         case Bytecodes::_invokespecial:
4252         case Bytecodes::_invokestatic:
4253         case Bytecodes::_invokeinterface:
4254           {
4255             Bytecode_invoke invoke(methodHandle(thread, sd->method()), sd->bci());
4256             st->print(" ");
4257             if (invoke.name() != nullptr)
4258               invoke.name()->print_symbol_on(st);
4259             else
4260               st->print("<UNKNOWN>");
4261             break;
4262           }
4263         case Bytecodes::_getfield:
4264         case Bytecodes::_putfield:
4265         case Bytecodes::_getstatic:
4266         case Bytecodes::_putstatic:
4267           {
4268             Bytecode_field field(methodHandle(thread, sd->method()), sd->bci());
4269             st->print(" ");
4270             if (field.name() != nullptr)
4271               field.name()->print_symbol_on(st);
4272             else
4273               st->print("<UNKNOWN>");
4274           }
4275         default:
4276           break;
4277         }
4278       }
4279       st->print(" {reexecute=%d rethrow=%d return_oop=%d}", sd->should_reexecute(), sd->rethrow_exception(), sd->return_oop());
4280     }
4281 
4282     // Print all scopes
4283     for (;sd != nullptr; sd = sd->sender()) {
4284       st->move_to(column, 6, 0);
4285       st->print("; -");
4286       if (sd->should_reexecute()) {
4287         st->print(" (reexecute)");
4288       }
4289       if (sd->method() == nullptr) {
4290         st->print("method is nullptr");
4291       } else {
4292         sd->method()->print_short_name(st);
4293       }
4294       int lineno = sd->method()->line_number_from_bci(sd->bci());
4295       if (lineno != -1) {
4296         st->print("@%d (line %d)", sd->bci(), lineno);
4297       } else {
4298         st->print("@%d", sd->bci());
4299       }
4300       st->cr();
4301     }
4302   }
4303 
4304   // Print relocation information
4305   // Prevent memory leak: allocating without ResourceMark.
4306   ResourceMark rm;
4307   const char* str = reloc_string_for(begin, end);
4308   if (str != nullptr) {
4309     if (sd != nullptr) st->cr();
4310     st->move_to(column, 6, 0);
4311     st->print(";   {%s}", str);
4312   }
4313 }
4314 
4315 #endif
4316 
4317 address nmethod::call_instruction_address(address pc) const {
4318   if (NativeCall::is_call_before(pc)) {
4319     NativeCall *ncall = nativeCall_before(pc);
4320     return ncall->instruction_address();
4321   }
4322   return nullptr;
4323 }
4324 
4325 void nmethod::print_value_on_impl(outputStream* st) const {
4326   st->print_cr("nmethod");
4327 #if defined(SUPPORT_DATA_STRUCTS)
4328   print_on_with_msg(st, nullptr);
4329 #endif
4330 }
4331 
4332 void nmethod::print_code_snippet(outputStream* st, address addr) const {
4333   if (entry_point() <= addr && addr < code_end()) {
4334     // Pointing into the nmethod's code. Try to disassemble some instructions around addr.
4335     // Determine conservative start and end points.
4336     address start;
4337     if (frame_complete_offset() != CodeOffsets::frame_never_safe &&
4338         addr >= code_begin() + frame_complete_offset()) {
4339       start = code_begin() + frame_complete_offset();
4340     } else {
4341       start = (addr < verified_entry_point()) ? entry_point() : verified_entry_point();
4342     }
4343     address start_for_hex_dump = start; // We can choose a different starting point for hex dump, below.
4344     address end = code_end();
4345 
4346     // Try using relocations to find closer instruction start and end points.
4347     // (Some platforms have variable length instructions and can only
4348     // disassemble correctly at instruction start addresses.)
4349     RelocIterator iter((nmethod*)this, start);
4350     while (iter.next() && iter.addr() < addr) { // find relocation before addr
4351       // Note: There's a relocation which doesn't point to an instruction start:
4352       // ZBarrierRelocationFormatStoreGoodAfterMov with ZGC on x86_64
4353       // We could detect and skip it, but hex dump is still usable when
4354       // disassembler produces garbage in such a very rare case.
4355       start = iter.addr();
4356       // We want at least 64 Bytes ahead in hex dump.
4357       if (iter.addr() <= (addr - 64)) start_for_hex_dump = iter.addr();
4358     }
4359     if (iter.has_current()) {
4360       if (iter.addr() == addr) iter.next(); // find relocation after addr
4361       if (iter.has_current()) end = iter.addr();
4362     }
4363 
4364     // Always print hex. Disassembler may still have problems when hitting an incorrect instruction start.
4365     os::print_hex_dump(st, start_for_hex_dump, end, 1, /* print_ascii=*/false);
4366     if (!Disassembler::is_abstract()) {
4367       Disassembler::decode(start, end, st);
4368     }
4369   }
4370 }
4371 
4372 #ifndef PRODUCT
4373 
4374 void nmethod::print_calls(outputStream* st) {
4375   RelocIterator iter(this);
4376   while (iter.next()) {
4377     switch (iter.type()) {
4378     case relocInfo::virtual_call_type: {
4379       CompiledICLocker ml_verify(this);
4380       CompiledIC_at(&iter)->print();
4381       break;
4382     }
4383     case relocInfo::static_call_type:
4384     case relocInfo::opt_virtual_call_type:
4385       st->print_cr("Direct call at " INTPTR_FORMAT, p2i(iter.reloc()->addr()));
4386       CompiledDirectCall::at(iter.reloc())->print();
4387       break;
4388     default:
4389       break;
4390     }
4391   }
4392 }
4393 
4394 void nmethod::print_statistics() {
4395   ttyLocker ttyl;
4396   if (xtty != nullptr)  xtty->head("statistics type='nmethod'");
4397   native_nmethod_stats.print_native_nmethod_stats();
4398 #ifdef COMPILER1
4399   c1_java_nmethod_stats.print_nmethod_stats("C1");
4400 #endif
4401 #ifdef COMPILER2
4402   c2_java_nmethod_stats.print_nmethod_stats("C2");
4403 #endif
4404 #if INCLUDE_JVMCI
4405   jvmci_java_nmethod_stats.print_nmethod_stats("JVMCI");
4406 #endif
4407   unknown_java_nmethod_stats.print_nmethod_stats("Unknown");
4408   DebugInformationRecorder::print_statistics();
4409   pc_nmethod_stats.print_pc_stats();
4410   Dependencies::print_statistics();
4411   ExternalsRecorder::print_statistics();
4412   if (xtty != nullptr)  xtty->tail("statistics");
4413 }
4414 
4415 #endif // !PRODUCT
4416 
4417 #if INCLUDE_JVMCI
4418 void nmethod::update_speculation(JavaThread* thread) {
4419   jlong speculation = thread->pending_failed_speculation();
4420   if (speculation != 0) {
4421     guarantee(jvmci_nmethod_data() != nullptr, "failed speculation in nmethod without failed speculation list");
4422     jvmci_nmethod_data()->add_failed_speculation(this, speculation);
4423     thread->set_pending_failed_speculation(0);
4424   }
4425 }
4426 
4427 const char* nmethod::jvmci_name() {
4428   if (jvmci_nmethod_data() != nullptr) {
4429     return jvmci_nmethod_data()->name();
4430   }
4431   return nullptr;
4432 }
4433 
4434 bool nmethod::jvmci_skip_profile_deopt() const {
4435   return jvmci_nmethod_data() != nullptr && !jvmci_nmethod_data()->profile_deopt();
4436 }
4437 #endif