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 #ifdef COMPILER2
  70 #include "runtime/hotCodeCollector.hpp"
  71 #endif // COMPILER2
  72 #include "runtime/icache.hpp"
  73 #include "runtime/jniHandles.inline.hpp"
  74 #include "runtime/orderAccess.hpp"
  75 #include "runtime/os.hpp"
  76 #include "runtime/safepointVerifiers.hpp"
  77 #include "runtime/serviceThread.hpp"
  78 #include "runtime/sharedRuntime.hpp"
  79 #include "runtime/signature.hpp"
  80 #include "runtime/threadWXSetters.inline.hpp"
  81 #include "runtime/vmThread.hpp"
  82 #include "utilities/align.hpp"
  83 #include "utilities/copy.hpp"
  84 #include "utilities/dtrace.hpp"
  85 #include "utilities/events.hpp"
  86 #include "utilities/globalDefinitions.hpp"
  87 #include "utilities/hashTable.hpp"
  88 #include "utilities/xmlstream.hpp"
  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 
 145   void note_nmethod(nmethod* nm) {
 146     nmethod_count += 1;
 147     total_nm_size       += nm->size();
 148     total_immut_size    += nm->immutable_data_size();
 149     total_mut_size      += nm->mutable_data_size();
 150     relocation_size     += nm->relocation_size();
 151     consts_size         += nm->consts_size();
 152     insts_size          += nm->insts_size();
 153     stub_size           += nm->stub_size();
 154     oops_size           += nm->oops_size();
 155     metadata_size       += nm->metadata_size();
 156     scopes_data_size    += nm->scopes_data_size();
 157     scopes_pcs_size     += nm->scopes_pcs_size();
 158     dependencies_size   += nm->dependencies_size();
 159     handler_table_size  += nm->handler_table_size();
 160     nul_chk_table_size  += nm->nul_chk_table_size();
 161   }
 162   void print_nmethod_stats(const char* name) {
 163     if (nmethod_count == 0)  return;
 164     tty->print_cr("Statistics for %u bytecoded nmethods for %s:", nmethod_count, name);
 165     uint total_size = total_nm_size + total_immut_size + total_mut_size;
 166     if (total_nm_size != 0) {
 167       tty->print_cr(" total size      = %u (100%%)", total_size);
 168       tty->print_cr(" in CodeCache    = %u (%f%%)", total_nm_size, (total_nm_size * 100.0f)/total_size);
 169     }
 170     uint header_size = (uint)(nmethod_count * sizeof(nmethod));
 171     if (nmethod_count != 0) {
 172       tty->print_cr("   header        = %u (%f%%)", header_size, (header_size * 100.0f)/total_nm_size);
 173     }
 174     if (consts_size != 0) {
 175       tty->print_cr("   constants     = %u (%f%%)", consts_size, (consts_size * 100.0f)/total_nm_size);
 176     }
 177     if (insts_size != 0) {
 178       tty->print_cr("   main code     = %u (%f%%)", insts_size, (insts_size * 100.0f)/total_nm_size);
 179     }
 180     if (stub_size != 0) {
 181       tty->print_cr("   stub code     = %u (%f%%)", stub_size, (stub_size * 100.0f)/total_nm_size);
 182     }
 183     if (oops_size != 0) {
 184       tty->print_cr("   oops          = %u (%f%%)", oops_size, (oops_size * 100.0f)/total_nm_size);
 185     }
 186     if (total_mut_size != 0) {
 187       tty->print_cr(" mutable data    = %u (%f%%)", total_mut_size, (total_mut_size * 100.0f)/total_size);
 188     }
 189     if (relocation_size != 0) {
 190       tty->print_cr("   relocation    = %u (%f%%)", relocation_size, (relocation_size * 100.0f)/total_mut_size);
 191     }
 192     if (metadata_size != 0) {
 193       tty->print_cr("   metadata      = %u (%f%%)", metadata_size, (metadata_size * 100.0f)/total_mut_size);
 194     }
 195     if (total_immut_size != 0) {
 196       tty->print_cr(" immutable data  = %u (%f%%)", total_immut_size, (total_immut_size * 100.0f)/total_size);
 197     }
 198     if (dependencies_size != 0) {
 199       tty->print_cr("   dependencies  = %u (%f%%)", dependencies_size, (dependencies_size * 100.0f)/total_immut_size);
 200     }
 201     if (nul_chk_table_size != 0) {
 202       tty->print_cr("   nul chk table = %u (%f%%)", nul_chk_table_size, (nul_chk_table_size * 100.0f)/total_immut_size);
 203     }
 204     if (handler_table_size != 0) {
 205       tty->print_cr("   handler table = %u (%f%%)", handler_table_size, (handler_table_size * 100.0f)/total_immut_size);
 206     }
 207     if (scopes_pcs_size != 0) {
 208       tty->print_cr("   scopes pcs    = %u (%f%%)", scopes_pcs_size, (scopes_pcs_size * 100.0f)/total_immut_size);
 209     }
 210     if (scopes_data_size != 0) {
 211       tty->print_cr("   scopes data   = %u (%f%%)", scopes_data_size, (scopes_data_size * 100.0f)/total_immut_size);
 212     }
 213   }
 214 };
 215 
 216 struct native_nmethod_stats_struct {
 217   uint native_nmethod_count;
 218   uint native_total_size;
 219   uint native_relocation_size;
 220   uint native_insts_size;
 221   uint native_oops_size;
 222   uint native_metadata_size;
 223   void note_native_nmethod(nmethod* nm) {
 224     native_nmethod_count += 1;
 225     native_total_size       += nm->size();
 226     native_relocation_size  += nm->relocation_size();
 227     native_insts_size       += nm->insts_size();
 228     native_oops_size        += nm->oops_size();
 229     native_metadata_size    += nm->metadata_size();
 230   }
 231   void print_native_nmethod_stats() {
 232     if (native_nmethod_count == 0)  return;
 233     tty->print_cr("Statistics for %u native nmethods:", native_nmethod_count);
 234     if (native_total_size != 0)       tty->print_cr(" N. total size  = %u", native_total_size);
 235     if (native_relocation_size != 0)  tty->print_cr(" N. relocation  = %u", native_relocation_size);
 236     if (native_insts_size != 0)       tty->print_cr(" N. main code   = %u", native_insts_size);
 237     if (native_oops_size != 0)        tty->print_cr(" N. oops        = %u", native_oops_size);
 238     if (native_metadata_size != 0)    tty->print_cr(" N. metadata    = %u", native_metadata_size);
 239   }
 240 };
 241 
 242 struct pc_nmethod_stats_struct {
 243   uint pc_desc_init;     // number of initialization of cache (= number of caches)
 244   uint pc_desc_queries;  // queries to nmethod::find_pc_desc
 245   uint pc_desc_approx;   // number of those which have approximate true
 246   uint pc_desc_repeats;  // number of _pc_descs[0] hits
 247   uint pc_desc_hits;     // number of LRU cache hits
 248   uint pc_desc_tests;    // total number of PcDesc examinations
 249   uint pc_desc_searches; // total number of quasi-binary search steps
 250   uint pc_desc_adds;     // number of LUR cache insertions
 251 
 252   void print_pc_stats() {
 253     tty->print_cr("PcDesc Statistics:  %u queries, %.2f comparisons per query",
 254                   pc_desc_queries,
 255                   (double)(pc_desc_tests + pc_desc_searches)
 256                   / pc_desc_queries);
 257     tty->print_cr("  caches=%d queries=%u/%u, hits=%u+%u, tests=%u+%u, adds=%u",
 258                   pc_desc_init,
 259                   pc_desc_queries, pc_desc_approx,
 260                   pc_desc_repeats, pc_desc_hits,
 261                   pc_desc_tests, pc_desc_searches, pc_desc_adds);
 262   }
 263 };
 264 
 265 #ifdef COMPILER1
 266 static java_nmethod_stats_struct c1_java_nmethod_stats;
 267 #endif
 268 #ifdef COMPILER2
 269 static java_nmethod_stats_struct c2_java_nmethod_stats;
 270 #endif
 271 static java_nmethod_stats_struct unknown_java_nmethod_stats;
 272 
 273 static native_nmethod_stats_struct native_nmethod_stats;
 274 static pc_nmethod_stats_struct pc_nmethod_stats;
 275 
 276 static void note_java_nmethod(nmethod* nm) {
 277 #ifdef COMPILER1
 278   if (nm->is_compiled_by_c1()) {
 279     c1_java_nmethod_stats.note_nmethod(nm);
 280   } else
 281 #endif
 282 #ifdef COMPILER2
 283   if (nm->is_compiled_by_c2()) {
 284     c2_java_nmethod_stats.note_nmethod(nm);
 285   } else
 286 #endif
 287   {
 288     unknown_java_nmethod_stats.note_nmethod(nm);
 289   }
 290 }
 291 #endif // !PRODUCT
 292 
 293 //---------------------------------------------------------------------------------
 294 
 295 
 296 ExceptionCache::ExceptionCache(Handle exception, address pc, address handler) {
 297   assert(pc != nullptr, "Must be non null");
 298   assert(exception.not_null(), "Must be non null");
 299   assert(handler != nullptr, "Must be non null");
 300 
 301   _count = 0;
 302   _exception_type = exception->klass();
 303   _next = nullptr;
 304   _purge_list_next = nullptr;
 305 
 306   add_address_and_handler(pc,handler);
 307 }
 308 
 309 
 310 address ExceptionCache::match(Handle exception, address pc) {
 311   assert(pc != nullptr,"Must be non null");
 312   assert(exception.not_null(),"Must be non null");
 313   if (exception->klass() == exception_type()) {
 314     return (test_address(pc));
 315   }
 316 
 317   return nullptr;
 318 }
 319 
 320 
 321 bool ExceptionCache::match_exception_with_space(Handle exception) {
 322   assert(exception.not_null(),"Must be non null");
 323   if (exception->klass() == exception_type() && count() < cache_size) {
 324     return true;
 325   }
 326   return false;
 327 }
 328 
 329 
 330 address ExceptionCache::test_address(address addr) {
 331   int limit = count();
 332   for (int i = 0; i < limit; i++) {
 333     if (pc_at(i) == addr) {
 334       return handler_at(i);
 335     }
 336   }
 337   return nullptr;
 338 }
 339 
 340 
 341 bool ExceptionCache::add_address_and_handler(address addr, address handler) {
 342   if (test_address(addr) == handler) return true;
 343 
 344   int index = count();
 345   if (index < cache_size) {
 346     set_pc_at(index, addr);
 347     set_handler_at(index, handler);
 348     increment_count();
 349     return true;
 350   }
 351   return false;
 352 }
 353 
 354 ExceptionCache* ExceptionCache::next() {
 355   return AtomicAccess::load(&_next);
 356 }
 357 
 358 void ExceptionCache::set_next(ExceptionCache *ec) {
 359   AtomicAccess::store(&_next, ec);
 360 }
 361 
 362 //-----------------------------------------------------------------------------
 363 
 364 
 365 // Helper used by both find_pc_desc methods.
 366 static inline bool match_desc(PcDesc* pc, int pc_offset, bool approximate) {
 367   NOT_PRODUCT(++pc_nmethod_stats.pc_desc_tests);
 368   if (!approximate) {
 369     return pc->pc_offset() == pc_offset;
 370   } else {
 371     // Do not look before the sentinel
 372     assert(pc_offset > PcDesc::lower_offset_limit, "illegal pc_offset");
 373     return pc_offset <= pc->pc_offset() && (pc-1)->pc_offset() < pc_offset;
 374   }
 375 }
 376 
 377 void PcDescCache::init_to(PcDesc* initial_pc_desc) {
 378   NOT_PRODUCT(++pc_nmethod_stats.pc_desc_init);
 379   // initialize the cache by filling it with benign (non-null) values
 380   assert(initial_pc_desc != nullptr && initial_pc_desc->pc_offset() == PcDesc::lower_offset_limit,
 381          "must start with a sentinel");
 382   for (int i = 0; i < cache_size; i++) {
 383     _pc_descs[i] = initial_pc_desc;
 384   }
 385 }
 386 
 387 PcDesc* PcDescCache::find_pc_desc(int pc_offset, bool approximate) {
 388   // Note: one might think that caching the most recently
 389   // read value separately would be a win, but one would be
 390   // wrong.  When many threads are updating it, the cache
 391   // line it's in would bounce between caches, negating
 392   // any benefit.
 393 
 394   // In order to prevent race conditions do not load cache elements
 395   // repeatedly, but use a local copy:
 396   PcDesc* res;
 397 
 398   // Step one:  Check the most recently added value.
 399   res = _pc_descs[0];
 400   assert(res != nullptr, "PcDesc cache should be initialized already");
 401 
 402   // Approximate only here since PcDescContainer::find_pc_desc() checked for exact case.
 403   if (approximate && match_desc(res, pc_offset, approximate)) {
 404     NOT_PRODUCT(++pc_nmethod_stats.pc_desc_repeats);
 405     return res;
 406   }
 407 
 408   // Step two:  Check the rest of the LRU cache.
 409   for (int i = 1; i < cache_size; ++i) {
 410     res = _pc_descs[i];
 411     if (res->pc_offset() < 0) break;  // optimization: skip empty cache
 412     if (match_desc(res, pc_offset, approximate)) {
 413       NOT_PRODUCT(++pc_nmethod_stats.pc_desc_hits);
 414       return res;
 415     }
 416   }
 417 
 418   // Report failure.
 419   return nullptr;
 420 }
 421 
 422 void PcDescCache::add_pc_desc(PcDesc* pc_desc) {
 423   NOT_PRODUCT(++pc_nmethod_stats.pc_desc_adds);
 424   // Update the LRU cache by shifting pc_desc forward.
 425   for (int i = 0; i < cache_size; i++)  {
 426     PcDesc* next = _pc_descs[i];
 427     _pc_descs[i] = pc_desc;
 428     pc_desc = next;
 429   }
 430 }
 431 
 432 // adjust pcs_size so that it is a multiple of both oopSize and
 433 // sizeof(PcDesc) (assumes that if sizeof(PcDesc) is not a multiple
 434 // of oopSize, then 2*sizeof(PcDesc) is)
 435 static int adjust_pcs_size(int pcs_size) {
 436   int nsize = align_up(pcs_size,   oopSize);
 437   if ((nsize % sizeof(PcDesc)) != 0) {
 438     nsize = pcs_size + sizeof(PcDesc);
 439   }
 440   assert((nsize % oopSize) == 0, "correct alignment");
 441   return nsize;
 442 }
 443 
 444 // Returns a string version of the method state.
 445 const char* nmethod::state() const {
 446   int state = get_state();
 447   switch (state) {
 448   case not_installed:
 449     return "not installed";
 450   case in_use:
 451     return "in use";
 452   case not_entrant:
 453     return "not_entrant";
 454   default:
 455     fatal("unexpected method state: %d", state);
 456     return nullptr;
 457   }
 458 }
 459 
 460 void nmethod::set_deoptimized_done() {
 461   ConditionalMutexLocker ml(NMethodState_lock, !NMethodState_lock->owned_by_self(), Mutex::_no_safepoint_check_flag);
 462   if (_deoptimization_status != deoptimize_done) { // can't go backwards
 463     AtomicAccess::store(&_deoptimization_status, deoptimize_done);
 464   }
 465 }
 466 
 467 ExceptionCache* nmethod::exception_cache_acquire() const {
 468   return AtomicAccess::load_acquire(&_exception_cache);
 469 }
 470 
 471 void nmethod::add_exception_cache_entry(ExceptionCache* new_entry) {
 472   assert(ExceptionCache_lock->owned_by_self(),"Must hold the ExceptionCache_lock");
 473   assert(new_entry != nullptr,"Must be non null");
 474   assert(new_entry->next() == nullptr, "Must be null");
 475 
 476   for (;;) {
 477     ExceptionCache *ec = exception_cache();
 478     if (ec != nullptr) {
 479       Klass* ex_klass = ec->exception_type();
 480       if (!ex_klass->is_loader_alive()) {
 481         // We must guarantee that entries are not inserted with new next pointer
 482         // edges to ExceptionCache entries with dead klasses, due to bad interactions
 483         // with concurrent ExceptionCache cleanup. Therefore, the inserts roll
 484         // the head pointer forward to the first live ExceptionCache, so that the new
 485         // next pointers always point at live ExceptionCaches, that are not removed due
 486         // to concurrent ExceptionCache cleanup.
 487         ExceptionCache* next = ec->next();
 488         if (AtomicAccess::cmpxchg(&_exception_cache, ec, next) == ec) {
 489           CodeCache::release_exception_cache(ec);
 490         }
 491         continue;
 492       }
 493       ec = exception_cache();
 494       if (ec != nullptr) {
 495         new_entry->set_next(ec);
 496       }
 497     }
 498     if (AtomicAccess::cmpxchg(&_exception_cache, ec, new_entry) == ec) {
 499       return;
 500     }
 501   }
 502 }
 503 
 504 void nmethod::clean_exception_cache() {
 505   // For each nmethod, only a single thread may call this cleanup function
 506   // at the same time, whether called in STW cleanup or concurrent cleanup.
 507   // Note that if the GC is processing exception cache cleaning in a concurrent phase,
 508   // then a single writer may contend with cleaning up the head pointer to the
 509   // first ExceptionCache node that has a Klass* that is alive. That is fine,
 510   // as long as there is no concurrent cleanup of next pointers from concurrent writers.
 511   // And the concurrent writers do not clean up next pointers, only the head.
 512   // Also note that concurrent readers will walk through Klass* pointers that are not
 513   // alive. That does not cause ABA problems, because Klass* is deleted after
 514   // a handshake with all threads, after all stale ExceptionCaches have been
 515   // unlinked. That is also when the CodeCache::exception_cache_purge_list()
 516   // is deleted, with all ExceptionCache entries that were cleaned concurrently.
 517   // That similarly implies that CAS operations on ExceptionCache entries do not
 518   // suffer from ABA problems as unlinking and deletion is separated by a global
 519   // handshake operation.
 520   ExceptionCache* prev = nullptr;
 521   ExceptionCache* curr = exception_cache_acquire();
 522 
 523   while (curr != nullptr) {
 524     ExceptionCache* next = curr->next();
 525 
 526     if (!curr->exception_type()->is_loader_alive()) {
 527       if (prev == nullptr) {
 528         // Try to clean head; this is contended by concurrent inserts, that
 529         // both lazily clean the head, and insert entries at the head. If
 530         // the CAS fails, the operation is restarted.
 531         if (AtomicAccess::cmpxchg(&_exception_cache, curr, next) != curr) {
 532           prev = nullptr;
 533           curr = exception_cache_acquire();
 534           continue;
 535         }
 536       } else {
 537         // It is impossible to during cleanup connect the next pointer to
 538         // an ExceptionCache that has not been published before a safepoint
 539         // prior to the cleanup. Therefore, release is not required.
 540         prev->set_next(next);
 541       }
 542       // prev stays the same.
 543 
 544       CodeCache::release_exception_cache(curr);
 545     } else {
 546       prev = curr;
 547     }
 548 
 549     curr = next;
 550   }
 551 }
 552 
 553 // public method for accessing the exception cache
 554 // These are the public access methods.
 555 address nmethod::handler_for_exception_and_pc(Handle exception, address pc) {
 556   // We never grab a lock to read the exception cache, so we may
 557   // have false negatives. This is okay, as it can only happen during
 558   // the first few exception lookups for a given nmethod.
 559   ExceptionCache* ec = exception_cache_acquire();
 560   while (ec != nullptr) {
 561     address ret_val;
 562     if ((ret_val = ec->match(exception,pc)) != nullptr) {
 563       return ret_val;
 564     }
 565     ec = ec->next();
 566   }
 567   return nullptr;
 568 }
 569 
 570 void nmethod::add_handler_for_exception_and_pc(Handle exception, address pc, address handler) {
 571   // There are potential race conditions during exception cache updates, so we
 572   // must own the ExceptionCache_lock before doing ANY modifications. Because
 573   // we don't lock during reads, it is possible to have several threads attempt
 574   // to update the cache with the same data. We need to check for already inserted
 575   // copies of the current data before adding it.
 576 
 577   MutexLocker ml(ExceptionCache_lock);
 578   ExceptionCache* target_entry = exception_cache_entry_for_exception(exception);
 579 
 580   if (target_entry == nullptr || !target_entry->add_address_and_handler(pc,handler)) {
 581     target_entry = new ExceptionCache(exception,pc,handler);
 582     add_exception_cache_entry(target_entry);
 583   }
 584 }
 585 
 586 // private method for handling exception cache
 587 // These methods are private, and used to manipulate the exception cache
 588 // directly.
 589 ExceptionCache* nmethod::exception_cache_entry_for_exception(Handle exception) {
 590   ExceptionCache* ec = exception_cache_acquire();
 591   while (ec != nullptr) {
 592     if (ec->match_exception_with_space(exception)) {
 593       return ec;
 594     }
 595     ec = ec->next();
 596   }
 597   return nullptr;
 598 }
 599 
 600 bool nmethod::is_at_poll_return(address pc) {
 601   RelocIterator iter(this, pc, pc+1);
 602   while (iter.next()) {
 603     if (iter.type() == relocInfo::poll_return_type)
 604       return true;
 605   }
 606   return false;
 607 }
 608 
 609 
 610 bool nmethod::is_at_poll_or_poll_return(address pc) {
 611   RelocIterator iter(this, pc, pc+1);
 612   while (iter.next()) {
 613     relocInfo::relocType t = iter.type();
 614     if (t == relocInfo::poll_return_type || t == relocInfo::poll_type)
 615       return true;
 616   }
 617   return false;
 618 }
 619 
 620 void nmethod::verify_oop_relocations() {
 621   // Ensure sure that the code matches the current oop values
 622   RelocIterator iter(this, nullptr, nullptr);
 623   while (iter.next()) {
 624     if (iter.type() == relocInfo::oop_type) {
 625       oop_Relocation* reloc = iter.oop_reloc();
 626       if (!reloc->oop_is_immediate()) {
 627         reloc->verify_oop_relocation();
 628       }
 629     }
 630   }
 631 }
 632 
 633 
 634 ScopeDesc* nmethod::scope_desc_at(address pc) {
 635   PcDesc* pd = pc_desc_at(pc);
 636   guarantee(pd != nullptr, "scope must be present");
 637   return new ScopeDesc(this, pd);
 638 }
 639 
 640 ScopeDesc* nmethod::scope_desc_near(address pc) {
 641   PcDesc* pd = pc_desc_near(pc);
 642   guarantee(pd != nullptr, "scope must be present");
 643   return new ScopeDesc(this, pd);
 644 }
 645 
 646 address nmethod::oops_reloc_begin() const {
 647   // If the method is not entrant then a JMP is plastered over the
 648   // first few bytes.  If an oop in the old code was there, that oop
 649   // should not get GC'd.  Skip the first few bytes of oops on
 650   // not-entrant methods.
 651   if (frame_complete_offset() != CodeOffsets::frame_never_safe &&
 652       code_begin() + frame_complete_offset() >
 653       verified_entry_point() + NativeJump::instruction_size)
 654   {
 655     // If we have a frame_complete_offset after the native jump, then there
 656     // is no point trying to look for oops before that. This is a requirement
 657     // for being allowed to scan oops concurrently.
 658     return code_begin() + frame_complete_offset();
 659   }
 660 
 661   address low_boundary = verified_entry_point();
 662   return low_boundary;
 663 }
 664 
 665 // Method that knows how to preserve outgoing arguments at call. This method must be
 666 // called with a frame corresponding to a Java invoke
 667 void nmethod::preserve_callee_argument_oops(frame fr, const RegisterMap *reg_map, OopClosure* f) {
 668   if (method() == nullptr) {
 669     return;
 670   }
 671 
 672   // handle the case of an anchor explicitly set in continuation code that doesn't have a callee
 673   JavaThread* thread = reg_map->thread();
 674   if ((thread->has_last_Java_frame() && fr.sp() == thread->last_Java_sp())
 675       JVMTI_ONLY(|| (method()->is_continuation_enter_intrinsic() && thread->on_monitor_waited_event()))) {
 676     return;
 677   }
 678 
 679   if (!method()->is_native()) {
 680     address pc = fr.pc();
 681     bool has_receiver, has_appendix;
 682     Symbol* signature;
 683 
 684     // The method attached by JIT-compilers should be used, if present.
 685     // Bytecode can be inaccurate in such case.
 686     Method* callee = attached_method_before_pc(pc);
 687     if (callee != nullptr) {
 688       has_receiver = !(callee->access_flags().is_static());
 689       has_appendix = false;
 690       signature    = callee->signature();
 691 
 692       // If inline types are passed as fields, use the extended signature
 693       // which contains the types of all (oop) fields of the inline type.
 694       if (is_compiled_by_c2() && callee->has_scalarized_args()) {
 695         const GrowableArray<SigEntry>* sig = callee->adapter()->get_sig_cc();
 696         assert(sig != nullptr, "sig should never be null");
 697         TempNewSymbol tmp_sig = SigEntry::create_symbol(sig);
 698         has_receiver = false; // The extended signature contains the receiver type
 699         fr.oops_compiled_arguments_do(tmp_sig, has_receiver, has_appendix, reg_map, f);
 700         return;
 701       }
 702     } else {
 703       SimpleScopeDesc ssd(this, pc);
 704 
 705       Bytecode_invoke call(methodHandle(Thread::current(), ssd.method()), ssd.bci());
 706       has_receiver = call.has_receiver();
 707       has_appendix = call.has_appendix();
 708       signature    = call.signature();
 709     }
 710 
 711     fr.oops_compiled_arguments_do(signature, has_receiver, has_appendix, reg_map, f);
 712   } else if (method()->is_continuation_enter_intrinsic()) {
 713     // This method only calls Continuation.enter()
 714     Symbol* signature = vmSymbols::continuationEnter_signature();
 715     fr.oops_compiled_arguments_do(signature, false, false, reg_map, f);
 716   }
 717 }
 718 
 719 Method* nmethod::attached_method(address call_instr) {
 720   assert(code_contains(call_instr), "not part of the nmethod");
 721   RelocIterator iter(this, call_instr, call_instr + 1);
 722   while (iter.next()) {
 723     if (iter.addr() == call_instr) {
 724       switch(iter.type()) {
 725         case relocInfo::static_call_type:      return iter.static_call_reloc()->method_value();
 726         case relocInfo::opt_virtual_call_type: return iter.opt_virtual_call_reloc()->method_value();
 727         case relocInfo::virtual_call_type:     return iter.virtual_call_reloc()->method_value();
 728         default:                               break;
 729       }
 730     }
 731   }
 732   return nullptr; // not found
 733 }
 734 
 735 Method* nmethod::attached_method_before_pc(address pc) {
 736   if (NativeCall::is_call_before(pc)) {
 737     NativeCall* ncall = nativeCall_before(pc);
 738     return attached_method(ncall->instruction_address());
 739   }
 740   return nullptr; // not a call
 741 }
 742 
 743 void nmethod::clear_inline_caches() {
 744   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");
 745   RelocIterator iter(this);
 746   while (iter.next()) {
 747     iter.reloc()->clear_inline_cache();
 748   }
 749 }
 750 
 751 #ifdef ASSERT
 752 // Check class_loader is alive for this bit of metadata.
 753 class CheckClass : public MetadataClosure {
 754   void do_metadata(Metadata* md) {
 755     Klass* klass = nullptr;
 756     if (md->is_klass()) {
 757       klass = ((Klass*)md);
 758     } else if (md->is_method()) {
 759       klass = ((Method*)md)->method_holder();
 760     } else if (md->is_methodData()) {
 761       klass = ((MethodData*)md)->method()->method_holder();
 762     } else if (md->is_methodCounters()) {
 763       klass = ((MethodCounters*)md)->method()->method_holder();
 764     } else {
 765       md->print();
 766       ShouldNotReachHere();
 767     }
 768     assert(klass->is_loader_alive(), "must be alive");
 769   }
 770 };
 771 #endif // ASSERT
 772 
 773 // Clean references to unloaded nmethods at addr from this one, which is not unloaded.
 774 template <typename CallsiteT>
 775 static void clean_if_nmethod_is_unloaded(CallsiteT* callsite, bool clean_all) {
 776   CodeBlob* cb = CodeCache::find_blob(callsite->destination());
 777   if (!cb->is_nmethod()) {
 778     return;
 779   }
 780   nmethod* nm = cb->as_nmethod();
 781   if (clean_all || !nm->is_in_use() || nm->is_unloading() || nm->method()->code() != nm) {
 782     callsite->set_to_clean();
 783   }
 784 }
 785 
 786 // Cleans caches in nmethods that point to either classes that are unloaded
 787 // or nmethods that are unloaded.
 788 //
 789 // Can be called either in parallel by G1 currently or after all
 790 // nmethods are unloaded.  Return postponed=true in the parallel case for
 791 // inline caches found that point to nmethods that are not yet visited during
 792 // the do_unloading walk.
 793 void nmethod::unload_nmethod_caches(bool unloading_occurred) {
 794   ResourceMark rm;
 795 
 796   // Exception cache only needs to be called if unloading occurred
 797   if (unloading_occurred) {
 798     clean_exception_cache();
 799   }
 800 
 801   cleanup_inline_caches_impl(unloading_occurred, false);
 802 
 803 #ifdef ASSERT
 804   // Check that the metadata embedded in the nmethod is alive
 805   CheckClass check_class;
 806   metadata_do(&check_class);
 807 #endif
 808 }
 809 
 810 void nmethod::run_nmethod_entry_barrier() {
 811   BarrierSetNMethod* bs_nm = BarrierSet::barrier_set()->barrier_set_nmethod();
 812   if (bs_nm != nullptr) {
 813     // We want to keep an invariant that nmethods found through iterations of a Thread's
 814     // nmethods found in safepoints have gone through an entry barrier and are not armed.
 815     // By calling this nmethod entry barrier, it plays along and acts
 816     // like any other nmethod found on the stack of a thread (fewer surprises).
 817     nmethod* nm = this;
 818     bool alive = bs_nm->nmethod_entry_barrier(nm);
 819     assert(alive, "should be alive");
 820   }
 821 }
 822 
 823 // Only called by whitebox test
 824 void nmethod::cleanup_inline_caches_whitebox() {
 825   assert_locked_or_safepoint(CodeCache_lock);
 826   CompiledICLocker ic_locker(this);
 827   cleanup_inline_caches_impl(false /* unloading_occurred */, true /* clean_all */);
 828 }
 829 
 830 address* nmethod::orig_pc_addr(const frame* fr) {
 831   return (address*) ((address)fr->unextended_sp() + orig_pc_offset());
 832 }
 833 
 834 // Called to clean up after class unloading for live nmethods
 835 void nmethod::cleanup_inline_caches_impl(bool unloading_occurred, bool clean_all) {
 836   assert(CompiledICLocker::is_safe(this), "mt unsafe call");
 837   ResourceMark rm;
 838 
 839   // Find all calls in an nmethod and clear the ones that point to bad nmethods.
 840   RelocIterator iter(this, oops_reloc_begin());
 841   bool is_in_static_stub = false;
 842   while(iter.next()) {
 843 
 844     switch (iter.type()) {
 845 
 846     case relocInfo::virtual_call_type:
 847       if (unloading_occurred) {
 848         // If class unloading occurred we first clear ICs where the cached metadata
 849         // is referring to an unloaded klass or method.
 850         CompiledIC_at(&iter)->clean_metadata();
 851       }
 852 
 853       clean_if_nmethod_is_unloaded(CompiledIC_at(&iter), clean_all);
 854       break;
 855 
 856     case relocInfo::opt_virtual_call_type:
 857     case relocInfo::static_call_type:
 858       clean_if_nmethod_is_unloaded(CompiledDirectCall::at(iter.reloc()), clean_all);
 859       break;
 860 
 861     case relocInfo::static_stub_type: {
 862       is_in_static_stub = true;
 863       break;
 864     }
 865 
 866     case relocInfo::metadata_type: {
 867       // Only the metadata relocations contained in static/opt virtual call stubs
 868       // contains the Method* passed to c2i adapters. It is the only metadata
 869       // relocation that needs to be walked, as it is the one metadata relocation
 870       // that violates the invariant that all metadata relocations have an oop
 871       // in the compiled method (due to deferred resolution and code patching).
 872 
 873       // This causes dead metadata to remain in compiled methods that are not
 874       // unloading. Unless these slippery metadata relocations of the static
 875       // stubs are at least cleared, subsequent class redefinition operations
 876       // will access potentially free memory, and JavaThread execution
 877       // concurrent to class unloading may call c2i adapters with dead methods.
 878       if (!is_in_static_stub) {
 879         // The first metadata relocation after a static stub relocation is the
 880         // metadata relocation of the static stub used to pass the Method* to
 881         // c2i adapters.
 882         continue;
 883       }
 884       is_in_static_stub = false;
 885       if (is_unloading()) {
 886         // If the nmethod itself is dying, then it may point at dead metadata.
 887         // Nobody should follow that metadata; it is strictly unsafe.
 888         continue;
 889       }
 890       metadata_Relocation* r = iter.metadata_reloc();
 891       Metadata* md = r->metadata_value();
 892       if (md != nullptr && md->is_method()) {
 893         Method* method = static_cast<Method*>(md);
 894         if (!method->method_holder()->is_loader_alive()) {
 895           AtomicAccess::store(r->metadata_addr(), (Method*)nullptr);
 896 
 897           if (!r->metadata_is_immediate()) {
 898             r->fix_metadata_relocation();
 899           }
 900         }
 901       }
 902       break;
 903     }
 904 
 905     default:
 906       break;
 907     }
 908   }
 909 }
 910 
 911 address nmethod::continuation_for_implicit_exception(address pc) {
 912   // Exception happened outside inline-cache check code => we are inside
 913   // an active nmethod => use cpc to determine a return address
 914   int exception_offset = int(pc - code_begin());
 915   int cont_offset = ImplicitExceptionTable(this).continuation_offset( exception_offset );
 916 #ifdef ASSERT
 917   if (cont_offset == 0) {
 918     Thread* thread = Thread::current();
 919     ResourceMark rm(thread);
 920     CodeBlob* cb = CodeCache::find_blob(pc);
 921     assert(cb != nullptr && cb == this, "");
 922 
 923     // Keep tty output consistent. To avoid ttyLocker, we buffer in stream, and print all at once.
 924     stringStream ss;
 925     ss.print_cr("implicit exception happened at " INTPTR_FORMAT, p2i(pc));
 926     print_on(&ss);
 927     // Buffering to a stringStream, disable internal buffering so it's not done twice.
 928     method()->print_codes_on(&ss, 0, false);
 929     print_code_on(&ss);
 930     print_pcs_on(&ss);
 931     tty->print("%s", ss.as_string()); // print all at once
 932   }
 933 #endif
 934   if (cont_offset == 0) {
 935     // Let the normal error handling report the exception
 936     return nullptr;
 937   }
 938   guarantee(cont_offset != exception_offset, "continuation offset and exception offset must be different");
 939   return code_begin() + cont_offset;
 940 }
 941 
 942 class HasEvolDependency : public MetadataClosure {
 943   bool _has_evol_dependency;
 944  public:
 945   HasEvolDependency() : _has_evol_dependency(false) {}
 946   void do_metadata(Metadata* md) {
 947     if (md->is_method()) {
 948       Method* method = (Method*)md;
 949       if (method->is_old()) {
 950         _has_evol_dependency = true;
 951       }
 952     }
 953   }
 954   bool has_evol_dependency() const { return _has_evol_dependency; }
 955 };
 956 
 957 bool nmethod::has_evol_metadata() {
 958   // Check the metadata in relocIter and CompiledIC and also deoptimize
 959   // any nmethod that has reference to old methods.
 960   HasEvolDependency check_evol;
 961   metadata_do(&check_evol);
 962   if (check_evol.has_evol_dependency() && log_is_enabled(Debug, redefine, class, nmethod)) {
 963     ResourceMark rm;
 964     log_debug(redefine, class, nmethod)
 965             ("Found evol dependency of nmethod %s.%s(%s) compile_id=%d on in nmethod metadata",
 966              _method->method_holder()->external_name(),
 967              _method->name()->as_C_string(),
 968              _method->signature()->as_C_string(),
 969              compile_id());
 970   }
 971   return check_evol.has_evol_dependency();
 972 }
 973 
 974 int nmethod::total_size() const {
 975   return
 976     consts_size()        +
 977     insts_size()         +
 978     stub_size()          +
 979     scopes_data_size()   +
 980     scopes_pcs_size()    +
 981     handler_table_size() +
 982     nul_chk_table_size();
 983 }
 984 
 985 const char* nmethod::compile_kind() const {
 986   if (is_osr_method())     return "osr";
 987   if (method() != nullptr && is_native_method()) {
 988     if (method()->is_continuation_native_intrinsic()) {
 989       return "cnt";
 990     }
 991     return "c2n";
 992   }
 993   return nullptr;
 994 }
 995 
 996 const char* nmethod::compiler_name() const {
 997   return compilertype2name(_compiler_type);
 998 }
 999 
1000 #ifdef ASSERT
1001 class CheckForOopsClosure : public OopClosure {
1002   bool _found_oop = false;
1003  public:
1004   virtual void do_oop(oop* o) { _found_oop = true; }
1005   virtual void do_oop(narrowOop* o) { _found_oop = true; }
1006   bool found_oop() { return _found_oop; }
1007 };
1008 class CheckForMetadataClosure : public MetadataClosure {
1009   bool _found_metadata = false;
1010   Metadata* _ignore = nullptr;
1011  public:
1012   CheckForMetadataClosure(Metadata* ignore) : _ignore(ignore) {}
1013   virtual void do_metadata(Metadata* md) { if (md != _ignore) _found_metadata = true; }
1014   bool found_metadata() { return _found_metadata; }
1015 };
1016 
1017 static void assert_no_oops_or_metadata(nmethod* nm) {
1018   if (nm == nullptr) return;
1019   assert(nm->oop_maps() == nullptr, "expectation");
1020 
1021   CheckForOopsClosure cfo;
1022   nm->oops_do(&cfo);
1023   assert(!cfo.found_oop(), "no oops allowed");
1024 
1025   // We allow an exception for the own Method, but require its class to be permanent.
1026   Method* own_method = nm->method();
1027   CheckForMetadataClosure cfm(/* ignore reference to own Method */ own_method);
1028   nm->metadata_do(&cfm);
1029   assert(!cfm.found_metadata(), "no metadata allowed");
1030 
1031   assert(own_method->method_holder()->class_loader_data()->is_permanent_class_loader_data(),
1032          "Method's class needs to be permanent");
1033 }
1034 #endif
1035 
1036 static int required_mutable_data_size(CodeBuffer* code_buffer) {
1037   return align_up(code_buffer->total_relocation_size(), oopSize) +
1038          align_up(code_buffer->total_metadata_size(), oopSize);
1039 }
1040 
1041 nmethod* nmethod::new_native_nmethod(const methodHandle& method,
1042   int compile_id,
1043   CodeBuffer *code_buffer,
1044   int vep_offset,
1045   int frame_complete,
1046   int frame_size,
1047   ByteSize basic_lock_owner_sp_offset,
1048   ByteSize basic_lock_sp_offset,
1049   OopMapSet* oop_maps,
1050   int exception_handler) {
1051   code_buffer->finalize_oop_references(method);
1052   // create nmethod
1053   nmethod* nm = nullptr;
1054   int native_nmethod_size = CodeBlob::allocation_size(code_buffer, sizeof(nmethod));
1055   {
1056     MutexLocker mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
1057 
1058     CodeOffsets offsets;
1059     offsets.set_value(CodeOffsets::Verified_Entry, vep_offset);
1060     offsets.set_value(CodeOffsets::Frame_Complete, frame_complete);
1061     if (exception_handler != -1) {
1062       offsets.set_value(CodeOffsets::Exceptions, exception_handler);
1063     }
1064 
1065     int mutable_data_size = required_mutable_data_size(code_buffer);
1066 
1067     // MH intrinsics are dispatch stubs which are compatible with NonNMethod space.
1068     // IsUnloadingBehaviour::is_unloading needs to handle them separately.
1069     bool allow_NonNMethod_space = method->can_be_allocated_in_NonNMethod_space();
1070     nm = new (native_nmethod_size, allow_NonNMethod_space)
1071     nmethod(method(), compiler_none, native_nmethod_size,
1072             compile_id, &offsets,
1073             code_buffer, frame_size,
1074             basic_lock_owner_sp_offset,
1075             basic_lock_sp_offset,
1076             oop_maps, mutable_data_size);
1077     DEBUG_ONLY( if (allow_NonNMethod_space) assert_no_oops_or_metadata(nm); )
1078     NOT_PRODUCT(if (nm != nullptr) native_nmethod_stats.note_native_nmethod(nm));
1079   }
1080 
1081   if (nm != nullptr) {
1082     // verify nmethod
1083     DEBUG_ONLY(nm->verify();) // might block
1084 
1085     nm->log_new_nmethod();
1086   }
1087   return nm;
1088 }
1089 
1090 nmethod* nmethod::new_nmethod(const methodHandle& method,
1091   int compile_id,
1092   int entry_bci,
1093   CodeOffsets* offsets,
1094   int orig_pc_offset,
1095   DebugInformationRecorder* debug_info,
1096   Dependencies* dependencies,
1097   CodeBuffer* code_buffer, int frame_size,
1098   OopMapSet* oop_maps,
1099   ExceptionHandlerTable* handler_table,
1100   ImplicitExceptionTable* nul_chk_table,
1101   AbstractCompiler* compiler,
1102   CompLevel comp_level,
1103   Flags flags)
1104 {
1105   assert(debug_info->oop_recorder() == code_buffer->oop_recorder(), "shared OR");
1106   code_buffer->finalize_oop_references(method);
1107   // create nmethod
1108   nmethod* nm = nullptr;
1109   int nmethod_size = CodeBlob::allocation_size(code_buffer, sizeof(nmethod));
1110 
1111   int immutable_data_size =
1112       adjust_pcs_size(debug_info->pcs_size())
1113     + align_up((int)dependencies->size_in_bytes(), oopSize)
1114     + align_up(handler_table->size_in_bytes()    , oopSize)
1115     + align_up(nul_chk_table->size_in_bytes()    , oopSize)
1116     + align_up(debug_info->data_size()           , oopSize);
1117 
1118   // First, allocate space for immutable data in C heap.
1119   address immutable_data = nullptr;
1120   if (immutable_data_size > 0) {
1121     immutable_data_size += ImmutableDataRefCountSize;
1122     immutable_data = (address)os::malloc(immutable_data_size, mtCode);
1123     if (immutable_data == nullptr) {
1124       vm_exit_out_of_memory(immutable_data_size, OOM_MALLOC_ERROR, "nmethod: no space for immutable data");
1125       return nullptr;
1126     }
1127   }
1128 
1129   int mutable_data_size = required_mutable_data_size(code_buffer);
1130 
1131   {
1132     MutexLocker mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
1133 
1134     nm = new (nmethod_size, comp_level)
1135     nmethod(method(), compiler->type(), nmethod_size, immutable_data_size, mutable_data_size,
1136             compile_id, entry_bci, immutable_data, offsets, orig_pc_offset,
1137             debug_info, dependencies, code_buffer, frame_size, oop_maps,
1138             handler_table, nul_chk_table, compiler, comp_level, flags);
1139 
1140     if (nm != nullptr) {
1141       // To make dependency checking during class loading fast, record
1142       // the nmethod dependencies in the classes it is dependent on.
1143       // This allows the dependency checking code to simply walk the
1144       // class hierarchy above the loaded class, checking only nmethods
1145       // which are dependent on those classes.  The slow way is to
1146       // check every nmethod for dependencies which makes it linear in
1147       // the number of methods compiled.  For applications with a lot
1148       // classes the slow way is too slow.
1149       for (Dependencies::DepStream deps(nm); deps.next(); ) {
1150         if (deps.type() == Dependencies::call_site_target_value) {
1151           // CallSite dependencies are managed on per-CallSite instance basis.
1152           oop call_site = deps.argument_oop(0);
1153           MethodHandles::add_dependent_nmethod(call_site, nm);
1154         } else {
1155           InstanceKlass* ik = deps.context_type();
1156           if (ik == nullptr) {
1157             continue;  // ignore things like evol_method
1158           }
1159           // record this nmethod as dependent on this klass
1160           ik->add_dependent_nmethod(nm);
1161         }
1162       }
1163       NOT_PRODUCT(if (nm != nullptr)  note_java_nmethod(nm));
1164     }
1165   }
1166   // Do verification and logging outside CodeCache_lock.
1167   if (nm != nullptr) {
1168     // Safepoints in nmethod::verify aren't allowed because nm hasn't been installed yet.
1169     DEBUG_ONLY(nm->verify();)
1170     nm->log_new_nmethod();
1171   }
1172   return nm;
1173 }
1174 
1175 // Fill in default values for various fields
1176 void nmethod::init_defaults(CodeBuffer *code_buffer, CodeOffsets* offsets) {
1177   assert(frame_complete_offset() == offsets->value(CodeOffsets::Frame_Complete), "offset truncated?");
1178 
1179   // avoid uninitialized fields, even for short time periods
1180   _exception_cache            = nullptr;
1181   _gc_data                    = nullptr;
1182   _oops_do_mark_link          = nullptr;
1183   _compiled_ic_data           = nullptr;
1184 
1185   _is_unloading_state         = 0;
1186   _state                      = not_installed;
1187 
1188   _has_flushed_dependencies   = false;
1189   _is_unlinked                = false;
1190   _load_reported              = false; // jvmti state
1191 
1192   _deoptimization_status      = not_marked;
1193 
1194   // SECT_CONSTS is first in code buffer so the offset should be 0.
1195   int consts_offset = code_buffer->total_offset_of(code_buffer->consts());
1196   assert(consts_offset == 0, "const_offset: %d", consts_offset);
1197 
1198   _stub_offset = content_offset() + code_buffer->total_offset_of(code_buffer->stubs());
1199 
1200   CHECKED_CAST(_entry_offset,              uint16_t, (offsets->value(CodeOffsets::Entry)));
1201   CHECKED_CAST(_verified_entry_offset,     uint16_t, (offsets->value(CodeOffsets::Verified_Entry)));
1202 
1203   _inline_entry_offset             = _entry_offset;
1204   _verified_inline_entry_offset    = _verified_entry_offset;
1205   _verified_inline_ro_entry_offset = _verified_entry_offset;
1206 
1207   _skipped_instructions_size = code_buffer->total_skipped_instructions_size();
1208 }
1209 
1210 // Post initialization
1211 void nmethod::post_init() {
1212   clear_unloading_state();
1213 
1214   finalize_relocations();
1215 
1216   // Flush generated code
1217   ICache::invalidate_range(code_begin(), code_size());
1218 
1219   Universe::heap()->register_nmethod(this);
1220 
1221 #ifdef COMPILER2
1222   HotCodeCollector::register_nmethod(this);
1223 #endif // COMPILER2
1224 
1225   DEBUG_ONLY(Universe::heap()->verify_nmethod(this));
1226 
1227   CodeCache::commit(this);
1228 }
1229 
1230 // For native wrappers
1231 nmethod::nmethod(
1232   Method* method,
1233   CompilerType type,
1234   int nmethod_size,
1235   int compile_id,
1236   CodeOffsets* offsets,
1237   CodeBuffer* code_buffer,
1238   int frame_size,
1239   ByteSize basic_lock_owner_sp_offset,
1240   ByteSize basic_lock_sp_offset,
1241   OopMapSet* oop_maps,
1242   int mutable_data_size)
1243   : CodeBlob("native nmethod", CodeBlobKind::Nmethod, code_buffer, nmethod_size, sizeof(nmethod),
1244              offsets->value(CodeOffsets::Frame_Complete), frame_size, oop_maps, false, mutable_data_size),
1245   _deoptimization_generation(0),
1246   _gc_epoch(CodeCache::gc_epoch()),
1247   _method(method),
1248   _native_receiver_sp_offset(basic_lock_owner_sp_offset),
1249   _native_basic_lock_sp_offset(basic_lock_sp_offset)
1250 {
1251   {
1252     DEBUG_ONLY(NoSafepointVerifier nsv;)
1253     assert_locked_or_safepoint(CodeCache_lock);
1254     assert(!method->has_scalarized_args(), "scalarized native wrappers not supported yet");
1255     init_defaults(code_buffer, offsets);
1256 
1257     _osr_entry_point         = nullptr;
1258     _pc_desc_container       = nullptr;
1259     _entry_bci               = InvocationEntryBci;
1260     _compile_id              = compile_id;
1261     _comp_level              = CompLevel_none;
1262     _compiler_type           = type;
1263     _orig_pc_offset          = 0;
1264     _num_stack_arg_slots     = 0;
1265 
1266     if (offsets->value(CodeOffsets::Exceptions) != -1) {
1267       // Continuation enter intrinsic
1268       _exception_offset      = code_offset() + offsets->value(CodeOffsets::Exceptions);
1269     } else {
1270       _exception_offset      = 0;
1271     }
1272     // Native wrappers do not have deopt handlers. Make the values
1273     // something that will never match a pc like the nmethod vtable entry
1274     _deopt_handler_entry_offset    = 0;
1275     _unwind_handler_offset   = 0;
1276 
1277     int metadata_size = align_up(code_buffer->total_metadata_size(), wordSize);
1278     assert(_mutable_data_size == _relocation_size + metadata_size,
1279            "wrong mutable data size: %d != %d + %d",
1280            _mutable_data_size, _relocation_size, metadata_size);
1281 
1282     // native wrapper does not have read-only data but we need unique not null address
1283     _immutable_data          = blob_end();
1284     _immutable_data_size     = 0;
1285     _nul_chk_table_offset    = 0;
1286     _handler_table_offset    = 0;
1287     _scopes_pcs_offset       = 0;
1288     _scopes_data_offset      = 0;
1289     _immutable_data_ref_count_offset = 0;
1290 
1291     code_buffer->copy_code_and_locs_to(this);
1292     code_buffer->copy_values_to(this);
1293 
1294     post_init();
1295   }
1296 
1297   if (PrintNativeNMethods || PrintDebugInfo || PrintRelocations || PrintDependencies) {
1298     ttyLocker ttyl;  // keep the following output all in one block
1299     // This output goes directly to the tty, not the compiler log.
1300     // To enable tools to match it up with the compilation activity,
1301     // be sure to tag this tty output with the compile ID.
1302     if (xtty != nullptr) {
1303       xtty->begin_head("print_native_nmethod");
1304       xtty->method(_method);
1305       xtty->stamp();
1306       xtty->end_head(" address='" INTPTR_FORMAT "'", (intptr_t) this);
1307     }
1308     // Print the header part, then print the requested information.
1309     // This is both handled in decode2(), called via print_code() -> decode()
1310     if (PrintNativeNMethods) {
1311       tty->print_cr("-------------------------- Assembly (native nmethod) ---------------------------");
1312       print_code();
1313       tty->print_cr("- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ");
1314 #if defined(SUPPORT_DATA_STRUCTS)
1315       if (AbstractDisassembler::show_structs()) {
1316         if (oop_maps != nullptr) {
1317           tty->print("oop maps:"); // oop_maps->print_on(tty) outputs a cr() at the beginning
1318           oop_maps->print_on(tty);
1319           tty->print_cr("- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ");
1320         }
1321       }
1322 #endif
1323     } else {
1324       print(); // print the header part only.
1325     }
1326 #if defined(SUPPORT_DATA_STRUCTS)
1327     if (AbstractDisassembler::show_structs()) {
1328       if (PrintRelocations) {
1329         print_relocations();
1330         tty->print_cr("- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ");
1331       }
1332     }
1333 #endif
1334     if (xtty != nullptr) {
1335       xtty->tail("print_native_nmethod");
1336     }
1337   }
1338 }
1339 
1340 
1341 nmethod::nmethod(const nmethod &nm) : CodeBlob(nm._name, nm._kind, nm._size, nm._header_size),
1342   _flags(nm._flags)
1343 {
1344 
1345   if (nm._oop_maps != nullptr) {
1346     _oop_maps                   = nm._oop_maps->clone();
1347   } else {
1348     _oop_maps                   = nullptr;
1349   }
1350 
1351   _size                         = nm._size;
1352   _relocation_size              = nm._relocation_size;
1353   _content_offset               = nm._content_offset;
1354   _code_offset                  = nm._code_offset;
1355   _data_offset                  = nm._data_offset;
1356   _frame_size                   = nm._frame_size;
1357 
1358   S390_ONLY( _ctable_offset     = nm._ctable_offset; )
1359 
1360   _header_size                  = nm._header_size;
1361   _frame_complete_offset        = nm._frame_complete_offset;
1362 
1363   _kind                         = nm._kind;
1364 
1365   _caller_must_gc_arguments     = nm._caller_must_gc_arguments;
1366 
1367 #ifndef PRODUCT
1368   _asm_remarks.share(nm._asm_remarks);
1369   _dbg_strings.share(nm._dbg_strings);
1370 #endif
1371 
1372   // Allocate memory and copy mutable data to C heap
1373   _mutable_data_size            = nm._mutable_data_size;
1374   if (_mutable_data_size > 0) {
1375     _mutable_data = (address)os::malloc(_mutable_data_size, mtCode);
1376     if (_mutable_data == nullptr) {
1377       vm_exit_out_of_memory(_mutable_data_size, OOM_MALLOC_ERROR, "nmethod: no space for mutable data");
1378     }
1379     memcpy(mutable_data_begin(), nm.mutable_data_begin(), nm.mutable_data_size());
1380   } else {
1381     _mutable_data               = nullptr;
1382   }
1383 
1384   _deoptimization_generation    = 0;
1385   _gc_epoch                     = CodeCache::gc_epoch();
1386   _method                       = nm._method;
1387   _osr_link                     = nullptr;
1388 
1389   _exception_cache              = nullptr;
1390   _gc_data                      = nullptr;
1391   _oops_do_mark_link            = nullptr;
1392   _compiled_ic_data             = nullptr;
1393 
1394   // Relocate the OSR entry point from nm to the new nmethod.
1395   if (nm._osr_entry_point == nullptr) {
1396     _osr_entry_point = nullptr;
1397   } else {
1398     address new_addr = nm._osr_entry_point - (address) &nm + (address) this;
1399     assert(new_addr >= code_begin() && new_addr < code_end(),
1400            "relocated address must be within code bounds");
1401     _osr_entry_point = new_addr;
1402   }
1403   _entry_offset                 = nm._entry_offset;
1404   _verified_entry_offset        = nm._verified_entry_offset;
1405   _inline_entry_offset             = nm._inline_entry_offset;
1406   _verified_inline_entry_offset    = nm._verified_inline_entry_offset;
1407   _verified_inline_ro_entry_offset = nm._verified_inline_ro_entry_offset;
1408 
1409   _entry_bci                    = nm._entry_bci;
1410   _immutable_data_size          = nm._immutable_data_size;
1411 
1412   _skipped_instructions_size    = nm._skipped_instructions_size;
1413   _stub_offset                  = nm._stub_offset;
1414   _exception_offset             = nm._exception_offset;
1415   _deopt_handler_entry_offset   = nm._deopt_handler_entry_offset;
1416   _unwind_handler_offset        = nm._unwind_handler_offset;
1417   _num_stack_arg_slots          = nm._num_stack_arg_slots;
1418   _nul_chk_table_offset         = nm._nul_chk_table_offset;
1419   _handler_table_offset         = nm._handler_table_offset;
1420   _scopes_pcs_offset            = nm._scopes_pcs_offset;
1421   _scopes_data_offset           = nm._scopes_data_offset;
1422   _immutable_data_ref_count_offset = nm._immutable_data_ref_count_offset;
1423 
1424   // Increment number of references to immutable data to share it between nmethods
1425   if (_immutable_data_size > 0) {
1426     _immutable_data             = nm._immutable_data;
1427     inc_immutable_data_ref_count();
1428   } else {
1429     _immutable_data             = blob_end();
1430   }
1431 
1432   _orig_pc_offset               = nm._orig_pc_offset;
1433   _compile_id                   = nm._compile_id;
1434   _comp_level                   = nm._comp_level;
1435   _compiler_type                = nm._compiler_type;
1436   _is_unloading_state           = nm._is_unloading_state;
1437   _state                        = not_installed;
1438 
1439   _has_flushed_dependencies     = nm._has_flushed_dependencies;
1440   _is_unlinked                  = nm._is_unlinked;
1441   _load_reported                = nm._load_reported;
1442 
1443   _deoptimization_status        = nm._deoptimization_status;
1444 
1445   if (nm._pc_desc_container != nullptr) {
1446     _pc_desc_container          = new PcDescContainer(scopes_pcs_begin());
1447   } else {
1448     _pc_desc_container          = nullptr;
1449   }
1450 
1451   // Copy nmethod contents excluding header
1452   // - Constant part          (doubles, longs and floats used in nmethod)
1453   // - Code part:
1454   //   - Code body
1455   //   - Exception handler
1456   //   - Stub code
1457   //   - OOP table
1458   memcpy(consts_begin(), nm.consts_begin(), nm.data_end() - nm.consts_begin());
1459 
1460   // Fix relocation
1461   RelocIterator iter(this);
1462   CodeBuffer src(&nm);
1463   CodeBuffer dst(this);
1464   while (iter.next()) {
1465 #ifdef USE_TRAMPOLINE_STUB_FIX_OWNER
1466     // After an nmethod is moved, some direct call sites may end up out of range.
1467     // CallRelocation::fix_relocation_after_move() assumes the target is always
1468     // reachable and does not check branch range. Calling it without range checks
1469     // could cause us to write an offset too large for the instruction.
1470     //
1471     // If a call site has a trampoline, we skip the normal call relocation. The
1472     // associated trampoline_stub_Relocation will handle the call and the
1473     // trampoline, including range checks and updating the branch as needed.
1474     //
1475     // If no trampoline exists, we can assume the call target is always
1476     // reachable and therefore within direct branch range, so calling
1477     // CallRelocation::fix_relocation_after_move() is safe.
1478     if (iter.reloc()->is_call()) {
1479       address trampoline = trampoline_stub_Relocation::get_trampoline_for(iter.reloc()->addr(), this);
1480       if (trampoline != nullptr) {
1481         continue;
1482       }
1483     }
1484 #endif
1485 
1486     iter.reloc()->fix_relocation_after_move(&src, &dst);
1487   }
1488 
1489   {
1490     MutexLocker ml(NMethodState_lock, Mutex::_no_safepoint_check_flag);
1491     clear_inline_caches();
1492   }
1493 
1494   post_init();
1495 }
1496 
1497 nmethod* nmethod::relocate(CodeBlobType code_blob_type) {
1498   assert(NMethodRelocation, "must enable use of function");
1499 
1500   // Locks required to be held by caller to ensure the nmethod
1501   // is not modified or purged from code cache during relocation
1502   assert_lock_strong(CodeCache_lock);
1503   assert_lock_strong(Compile_lock);
1504   assert(CompiledICLocker::is_safe(this), "mt unsafe call");
1505 
1506   if (!is_relocatable()) {
1507     return nullptr;
1508   }
1509 
1510   run_nmethod_entry_barrier();
1511   nmethod* nm_copy = new (size(), code_blob_type) nmethod(*this);
1512 
1513   if (nm_copy == nullptr) {
1514     return nullptr;
1515   }
1516 
1517   // To make dependency checking during class loading fast, record
1518   // the nmethod dependencies in the classes it is dependent on.
1519   // This allows the dependency checking code to simply walk the
1520   // class hierarchy above the loaded class, checking only nmethods
1521   // which are dependent on those classes.  The slow way is to
1522   // check every nmethod for dependencies which makes it linear in
1523   // the number of methods compiled.  For applications with a lot
1524   // classes the slow way is too slow.
1525   for (Dependencies::DepStream deps(nm_copy); deps.next(); ) {
1526     if (deps.type() == Dependencies::call_site_target_value) {
1527       // CallSite dependencies are managed on per-CallSite instance basis.
1528       oop call_site = deps.argument_oop(0);
1529       MethodHandles::add_dependent_nmethod(call_site, nm_copy);
1530     } else {
1531       InstanceKlass* ik = deps.context_type();
1532       if (ik == nullptr) {
1533         continue;  // ignore things like evol_method
1534       }
1535       // record this nmethod as dependent on this klass
1536       ik->add_dependent_nmethod(nm_copy);
1537     }
1538   }
1539 
1540   MutexLocker ml_NMethodState_lock(NMethodState_lock, Mutex::_no_safepoint_check_flag);
1541 
1542   // Verify the nm we copied from is still valid
1543   if (!is_marked_for_deoptimization() && is_in_use()) {
1544     assert(method() != nullptr && method()->code() == this, "should be if is in use");
1545 
1546     // Attempt to start using the copy
1547     if (nm_copy->make_in_use()) {
1548       methodHandle mh(Thread::current(), nm_copy->method());
1549       nm_copy->method()->set_code(mh, nm_copy);
1550 
1551       make_not_entrant(InvalidationReason::RELOCATED);
1552 
1553       nm_copy->post_compiled_method_load_event();
1554 
1555       nm_copy->log_relocated_nmethod(this);
1556 
1557       return nm_copy;
1558     }
1559   }
1560 
1561   nm_copy->make_not_used();
1562 
1563   return nullptr;
1564 }
1565 
1566 bool nmethod::is_relocatable() {
1567   if (!is_java_method()) {
1568     return false;
1569   }
1570 
1571   if (!is_in_use()) {
1572     return false;
1573   }
1574 
1575   if (is_osr_method()) {
1576     return false;
1577   }
1578 
1579   if (is_marked_for_deoptimization()) {
1580     return false;
1581   }
1582 
1583   if (is_unloading()) {
1584     return false;
1585   }
1586 
1587   if (has_evol_metadata()) {
1588     return false;
1589   }
1590 
1591   return true;
1592 }
1593 
1594 void* nmethod::operator new(size_t size, int nmethod_size, int comp_level) throw () {
1595   return CodeCache::allocate(nmethod_size, CodeCache::get_code_blob_type(comp_level));
1596 }
1597 
1598 void* nmethod::operator new(size_t size, int nmethod_size, CodeBlobType code_blob_type) throw () {
1599   return CodeCache::allocate(nmethod_size, code_blob_type);
1600 }
1601 
1602 void* nmethod::operator new(size_t size, int nmethod_size, bool allow_NonNMethod_space) throw () {
1603   // Try MethodNonProfiled and MethodProfiled.
1604   void* return_value = CodeCache::allocate(nmethod_size, CodeBlobType::MethodNonProfiled);
1605   if (return_value != nullptr || !allow_NonNMethod_space) return return_value;
1606   // Try NonNMethod or give up.
1607   return CodeCache::allocate(nmethod_size, CodeBlobType::NonNMethod);
1608 }
1609 
1610 // For normal JIT compiled code
1611 nmethod::nmethod(
1612   Method* method,
1613   CompilerType type,
1614   int nmethod_size,
1615   int immutable_data_size,
1616   int mutable_data_size,
1617   int compile_id,
1618   int entry_bci,
1619   address immutable_data,
1620   CodeOffsets* offsets,
1621   int orig_pc_offset,
1622   DebugInformationRecorder* debug_info,
1623   Dependencies* dependencies,
1624   CodeBuffer *code_buffer,
1625   int frame_size,
1626   OopMapSet* oop_maps,
1627   ExceptionHandlerTable* handler_table,
1628   ImplicitExceptionTable* nul_chk_table,
1629   AbstractCompiler* compiler,
1630   CompLevel comp_level,
1631   Flags flags)
1632   : CodeBlob("nmethod", CodeBlobKind::Nmethod, code_buffer, nmethod_size, sizeof(nmethod),
1633              offsets->value(CodeOffsets::Frame_Complete), frame_size, oop_maps, false, mutable_data_size),
1634   _deoptimization_generation(0),
1635   _gc_epoch(CodeCache::gc_epoch()),
1636   _method(method),
1637   _osr_link(nullptr),
1638   _flags(flags)
1639 {
1640   assert(debug_info->oop_recorder() == code_buffer->oop_recorder(), "shared OR");
1641   {
1642     DEBUG_ONLY(NoSafepointVerifier nsv;)
1643     assert_locked_or_safepoint(CodeCache_lock);
1644 
1645     init_defaults(code_buffer, offsets);
1646 
1647     _osr_entry_point = code_begin() + offsets->value(CodeOffsets::OSR_Entry);
1648     _entry_bci       = entry_bci;
1649     _compile_id      = compile_id;
1650     _comp_level      = comp_level;
1651     _compiler_type   = type;
1652     _orig_pc_offset  = orig_pc_offset;
1653 
1654     _num_stack_arg_slots = entry_bci != InvocationEntryBci ? 0 : _method->constMethod()->num_stack_arg_slots();
1655 
1656     set_ctable_begin(header_begin() + content_offset());
1657 
1658     // Exception handler and deopt handler are in the stub section
1659     assert(offsets->value(CodeOffsets::Deopt     ) != -1, "must be set");
1660 
1661     bool has_exception_handler = (offsets->value(CodeOffsets::Exceptions) != -1);
1662     assert(has_exception_handler == (compiler->type() != compiler_c2),
1663            "C2 compiler doesn't provide exception handler stub code.");
1664     if (has_exception_handler) {
1665       _exception_offset = _stub_offset + offsets->value(CodeOffsets::Exceptions);
1666     } else {
1667       _exception_offset = -1;
1668     }
1669 
1670     _deopt_handler_entry_offset = _stub_offset + offsets->value(CodeOffsets::Deopt);
1671 
1672     if (offsets->value(CodeOffsets::UnwindHandler) != -1) {
1673       // C1 generates UnwindHandler at the end of instructions section.
1674       // Calculate positive offset as distance between the start of stubs section
1675       // (which is also the end of instructions section) and the start of the handler.
1676       int unwind_handler_offset = code_offset() + offsets->value(CodeOffsets::UnwindHandler);
1677       CHECKED_CAST(_unwind_handler_offset, int16_t, (_stub_offset - unwind_handler_offset));
1678     } else {
1679       _unwind_handler_offset = -1;
1680     }
1681 
1682     int metadata_size = align_up(code_buffer->total_metadata_size(), wordSize);
1683     if (offsets->value(CodeOffsets::Inline_Entry) != CodeOffsets::no_such_entry_point) {
1684       CHECKED_CAST(_inline_entry_offset            , uint16_t, offsets->value(CodeOffsets::Inline_Entry));
1685     }
1686     if (offsets->value(CodeOffsets::Verified_Inline_Entry) != CodeOffsets::no_such_entry_point) {
1687       CHECKED_CAST(_verified_inline_entry_offset   , uint16_t, offsets->value(CodeOffsets::Verified_Inline_Entry));
1688     }
1689     if (offsets->value(CodeOffsets::Verified_Inline_Entry_RO) != CodeOffsets::no_such_entry_point) {
1690       CHECKED_CAST(_verified_inline_ro_entry_offset, uint16_t, offsets->value(CodeOffsets::Verified_Inline_Entry_RO));
1691     }
1692 
1693     assert(_mutable_data_size == _relocation_size + metadata_size,
1694            "wrong mutable data size: %d != %d + %d",
1695            _mutable_data_size, _relocation_size, metadata_size);
1696     assert(nmethod_size == data_end() - header_begin(), "wrong nmethod size: %d != %d",
1697            nmethod_size, (int)(code_end() - header_begin()));
1698 
1699     _immutable_data_size  = immutable_data_size;
1700     if (immutable_data_size > 0) {
1701       assert(immutable_data != nullptr, "required");
1702       _immutable_data     = immutable_data;
1703     } else {
1704       // We need unique not null address
1705       _immutable_data     = blob_end();
1706     }
1707     CHECKED_CAST(_nul_chk_table_offset, uint16_t, (align_up((int)dependencies->size_in_bytes(), oopSize)));
1708     CHECKED_CAST(_handler_table_offset, uint16_t, (_nul_chk_table_offset + align_up(nul_chk_table->size_in_bytes(), oopSize)));
1709     _scopes_pcs_offset    = _handler_table_offset + align_up(handler_table->size_in_bytes(), oopSize);
1710     _scopes_data_offset   = _scopes_pcs_offset    + adjust_pcs_size(debug_info->pcs_size());
1711 
1712     _immutable_data_ref_count_offset = _scopes_data_offset + align_up(debug_info->data_size(), oopSize);
1713     DEBUG_ONLY( int immutable_data_end_offset = _immutable_data_ref_count_offset + ImmutableDataRefCountSize; )
1714     assert(immutable_data_end_offset <= immutable_data_size, "wrong read-only data size: %d > %d",
1715            immutable_data_end_offset, immutable_data_size);
1716 
1717     // Copy code and relocation info
1718     code_buffer->copy_code_and_locs_to(this);
1719     // Copy oops and metadata
1720     code_buffer->copy_values_to(this);
1721     dependencies->copy_to(this);
1722     // Copy PcDesc and ScopeDesc data
1723     debug_info->copy_to(this);
1724 
1725     // Create cache after PcDesc data is copied - it will be used to initialize cache
1726     _pc_desc_container = new PcDescContainer(scopes_pcs_begin());
1727 
1728     // Copy contents of ExceptionHandlerTable to nmethod
1729     handler_table->copy_to(this);
1730     nul_chk_table->copy_to(this);
1731 
1732     init_immutable_data_ref_count();
1733 
1734     post_init();
1735 
1736     // we use the information of entry points to find out if a method is
1737     // static or non static
1738     assert(compiler->is_c2() ||
1739            _method->is_static() == (entry_point() == verified_entry_point()),
1740            " entry points must be same for static methods and vice versa");
1741   }
1742 }
1743 
1744 // Print a short set of xml attributes to identify this nmethod.  The
1745 // output should be embedded in some other element.
1746 void nmethod::log_identity(xmlStream* log) const {
1747   log->print(" compile_id='%d'", compile_id());
1748   const char* nm_kind = compile_kind();
1749   if (nm_kind != nullptr)  log->print(" compile_kind='%s'", nm_kind);
1750   log->print(" compiler='%s'", compiler_name());
1751   if (TieredCompilation) {
1752     log->print(" level='%d'", comp_level());
1753   }
1754 }
1755 
1756 
1757 #define LOG_OFFSET(log, name)                    \
1758   if (p2i(name##_end()) - p2i(name##_begin())) \
1759     log->print(" " XSTR(name) "_offset='%zd'"    , \
1760                p2i(name##_begin()) - p2i(this))
1761 
1762 
1763 void nmethod::log_new_nmethod() const {
1764   if (LogCompilation && xtty != nullptr) {
1765     ttyLocker ttyl;
1766     xtty->begin_elem("nmethod");
1767     log_identity(xtty);
1768     xtty->print(" entry='" INTPTR_FORMAT "' size='%d'", p2i(code_begin()), size());
1769     xtty->print(" address='" INTPTR_FORMAT "'", p2i(this));
1770 
1771     LOG_OFFSET(xtty, relocation);
1772     LOG_OFFSET(xtty, consts);
1773     LOG_OFFSET(xtty, insts);
1774     LOG_OFFSET(xtty, stub);
1775     LOG_OFFSET(xtty, scopes_data);
1776     LOG_OFFSET(xtty, scopes_pcs);
1777     LOG_OFFSET(xtty, dependencies);
1778     LOG_OFFSET(xtty, handler_table);
1779     LOG_OFFSET(xtty, nul_chk_table);
1780     LOG_OFFSET(xtty, oops);
1781     LOG_OFFSET(xtty, metadata);
1782 
1783     xtty->method(method());
1784     xtty->stamp();
1785     xtty->end_elem();
1786   }
1787 }
1788 
1789 
1790 void nmethod::log_relocated_nmethod(nmethod* original) const {
1791   if (LogCompilation && xtty != nullptr) {
1792     ttyLocker ttyl;
1793     xtty->begin_elem("relocated nmethod");
1794     log_identity(xtty);
1795     xtty->print(" entry='" INTPTR_FORMAT "' size='%d'", p2i(code_begin()), size());
1796 
1797     const char* original_code_heap_name = CodeCache::get_code_heap_name(CodeCache::get_code_blob_type(original));
1798     xtty->print(" original_address='" INTPTR_FORMAT "'", p2i(original));
1799     xtty->print(" original_code_heap='%s'", original_code_heap_name);
1800 
1801     const char* new_code_heap_name = CodeCache::get_code_heap_name(CodeCache::get_code_blob_type(this));
1802     xtty->print(" new_address='" INTPTR_FORMAT "'", p2i(this));
1803     xtty->print(" new_code_heap='%s'", new_code_heap_name);
1804 
1805     LOG_OFFSET(xtty, relocation);
1806     LOG_OFFSET(xtty, consts);
1807     LOG_OFFSET(xtty, insts);
1808     LOG_OFFSET(xtty, stub);
1809     LOG_OFFSET(xtty, scopes_data);
1810     LOG_OFFSET(xtty, scopes_pcs);
1811     LOG_OFFSET(xtty, dependencies);
1812     LOG_OFFSET(xtty, handler_table);
1813     LOG_OFFSET(xtty, nul_chk_table);
1814     LOG_OFFSET(xtty, oops);
1815     LOG_OFFSET(xtty, metadata);
1816 
1817     xtty->method(method());
1818     xtty->stamp();
1819     xtty->end_elem();
1820   }
1821 }
1822 
1823 #undef LOG_OFFSET
1824 
1825 
1826 // Print out more verbose output usually for a newly created nmethod.
1827 void nmethod::print_on_with_msg(outputStream* st, const char* msg) const {
1828   if (st != nullptr) {
1829     ttyLocker ttyl;
1830     if (WizardMode) {
1831       CompileTask::print(st, this, msg, /*short_form:*/ true);
1832       st->print_cr(" (" INTPTR_FORMAT ")", p2i(this));
1833     } else {
1834       CompileTask::print(st, this, msg, /*short_form:*/ false);
1835     }
1836   }
1837 }
1838 
1839 void nmethod::maybe_print_nmethod(const DirectiveSet* directive) {
1840   bool printnmethods = directive->PrintAssemblyOption || directive->PrintNMethodsOption;
1841   if (printnmethods || PrintDebugInfo || PrintRelocations || PrintDependencies || PrintExceptionHandlers) {
1842     print_nmethod(printnmethods);
1843   }
1844 }
1845 
1846 void nmethod::print_nmethod(bool printmethod) {
1847   ttyLocker ttyl;  // keep the following output all in one block
1848   if (xtty != nullptr) {
1849     xtty->begin_head("print_nmethod");
1850     log_identity(xtty);
1851     xtty->stamp();
1852     xtty->end_head();
1853   }
1854   // Print the header part, then print the requested information.
1855   // This is both handled in decode2().
1856   if (printmethod) {
1857     ResourceMark m;
1858     if (is_compiled_by_c1()) {
1859       tty->cr();
1860       tty->print_cr("============================= C1-compiled nmethod ==============================");
1861     }
1862     tty->print_cr("----------------------------------- Assembly -----------------------------------");
1863     decode2(tty);
1864 #if defined(SUPPORT_DATA_STRUCTS)
1865     if (AbstractDisassembler::show_structs()) {
1866       // Print the oops from the underlying CodeBlob as well.
1867       tty->print_cr("- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ");
1868       print_oops(tty);
1869       tty->print_cr("- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ");
1870       print_metadata(tty);
1871       tty->print_cr("- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ");
1872       print_pcs_on(tty);
1873       tty->print_cr("- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ");
1874       if (oop_maps() != nullptr) {
1875         tty->print("oop maps:"); // oop_maps()->print_on(tty) outputs a cr() at the beginning
1876         oop_maps()->print_on(tty);
1877         tty->print_cr("- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ");
1878       }
1879     }
1880 #endif
1881   } else {
1882     print(); // print the header part only.
1883   }
1884 
1885 #if defined(SUPPORT_DATA_STRUCTS)
1886   if (AbstractDisassembler::show_structs()) {
1887     methodHandle mh(Thread::current(), _method);
1888     if (printmethod || PrintDebugInfo || CompilerOracle::has_option(mh, CompileCommandEnum::PrintDebugInfo)) {
1889       print_scopes();
1890       tty->print_cr("- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ");
1891     }
1892     if (printmethod || PrintRelocations || CompilerOracle::has_option(mh, CompileCommandEnum::PrintRelocations)) {
1893       print_relocations();
1894       tty->print_cr("- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ");
1895     }
1896     if (printmethod || PrintDependencies || CompilerOracle::has_option(mh, CompileCommandEnum::PrintDependencies)) {
1897       print_dependencies_on(tty);
1898       tty->print_cr("- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ");
1899     }
1900     if (printmethod || PrintExceptionHandlers) {
1901       print_handler_table();
1902       tty->print_cr("- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ");
1903       print_nul_chk_table();
1904       tty->print_cr("- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ");
1905     }
1906 
1907     if (printmethod) {
1908       print_recorded_oops();
1909       tty->print_cr("- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ");
1910       print_recorded_metadata();
1911       tty->print_cr("- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ");
1912     }
1913   }
1914 #endif
1915 
1916   if (xtty != nullptr) {
1917     xtty->tail("print_nmethod");
1918   }
1919 }
1920 
1921 
1922 // Promote one word from an assembly-time handle to a live embedded oop.
1923 inline void nmethod::initialize_immediate_oop(oop* dest, jobject handle) {
1924   if (handle == nullptr ||
1925       // As a special case, IC oops are initialized to 1 or -1.
1926       handle == (jobject) Universe::non_oop_word()) {
1927     *(void**)dest = handle;
1928   } else {
1929     *dest = JNIHandles::resolve_non_null(handle);
1930   }
1931 }
1932 
1933 
1934 // Have to have the same name because it's called by a template
1935 void nmethod::copy_values(GrowableArray<jobject>* array) {
1936   int length = array->length();
1937   assert((address)(oops_begin() + length) <= (address)oops_end(), "oops big enough");
1938   oop* dest = oops_begin();
1939   for (int index = 0 ; index < length; index++) {
1940     initialize_immediate_oop(&dest[index], array->at(index));
1941   }
1942 
1943   // Now we can fix up all the oops in the code.  We need to do this
1944   // in the code because the assembler uses jobjects as placeholders.
1945   // The code and relocations have already been initialized by the
1946   // CodeBlob constructor, so it is valid even at this early point to
1947   // iterate over relocations and patch the code.
1948   fix_oop_relocations(/*initialize_immediates=*/ true);
1949 }
1950 
1951 void nmethod::copy_values(GrowableArray<Metadata*>* array) {
1952   int length = array->length();
1953   assert((address)(metadata_begin() + length) <= (address)metadata_end(), "big enough");
1954   Metadata** dest = metadata_begin();
1955   for (int index = 0 ; index < length; index++) {
1956     dest[index] = array->at(index);
1957   }
1958 }
1959 
1960 bool nmethod::fix_oop_relocations(bool initialize_immediates) {
1961   // re-patch all oop-bearing instructions, just in case some oops moved
1962   RelocIterator iter(this);
1963   bool modified_code = false;
1964   while (iter.next()) {
1965     if (iter.type() == relocInfo::oop_type) {
1966       oop_Relocation* reloc = iter.oop_reloc();
1967       if (!reloc->oop_is_immediate()) {
1968         // Refresh the oop-related bits of this instruction.
1969         reloc->set_value(reloc->value());
1970         modified_code = true;
1971       } else if (initialize_immediates) {
1972         oop* dest = reloc->oop_addr();
1973         jobject obj = *reinterpret_cast<jobject*>(dest);
1974         initialize_immediate_oop(dest, obj);
1975       }
1976     } else if (iter.type() == relocInfo::metadata_type) {
1977       metadata_Relocation* reloc = iter.metadata_reloc();
1978       reloc->fix_metadata_relocation();
1979       modified_code |= !reloc->metadata_is_immediate();
1980     }
1981   }
1982   return modified_code;
1983 }
1984 
1985 void nmethod::fix_oop_relocations() {
1986   ICacheInvalidationContext icic;
1987   fix_oop_relocations(&icic);
1988 }
1989 
1990 void nmethod::fix_oop_relocations(ICacheInvalidationContext* icic) {
1991   assert(icic != nullptr, "must provide context to track if code was modified");
1992   bool modified_code = fix_oop_relocations(/*initialize_immediates=*/ false);
1993   if (modified_code) {
1994     icic->set_has_modified_code();
1995   }
1996 }
1997 
1998 static void install_post_call_nop_displacement(nmethod* nm, address pc) {
1999   NativePostCallNop* nop = nativePostCallNop_at((address) pc);
2000   intptr_t cbaddr = (intptr_t) nm;
2001   intptr_t offset = ((intptr_t) pc) - cbaddr;
2002 
2003   int oopmap_slot = nm->oop_maps()->find_slot_for_offset(int((intptr_t) pc - (intptr_t) nm->code_begin()));
2004   if (oopmap_slot < 0) { // this can happen at asynchronous (non-safepoint) stackwalks
2005     log_debug(codecache)("failed to find oopmap for cb: " INTPTR_FORMAT " offset: %d", cbaddr, (int) offset);
2006   } else if (!nop->patch(oopmap_slot, offset)) {
2007     log_debug(codecache)("failed to encode %d %d", oopmap_slot, (int) offset);
2008   }
2009 }
2010 
2011 void nmethod::finalize_relocations() {
2012   NoSafepointVerifier nsv;
2013 
2014   GrowableArray<NativeMovConstReg*> virtual_call_data;
2015 
2016   // Make sure that post call nops fill in nmethod offsets eagerly so
2017   // we don't have to race with deoptimization
2018   RelocIterator iter(this);
2019   while (iter.next()) {
2020     if (iter.type() == relocInfo::virtual_call_type) {
2021       virtual_call_Relocation* r = iter.virtual_call_reloc();
2022       NativeMovConstReg* value = nativeMovConstReg_at(r->cached_value());
2023       virtual_call_data.append(value);
2024     } else if (iter.type() == relocInfo::post_call_nop_type) {
2025       post_call_nop_Relocation* const reloc = iter.post_call_nop_reloc();
2026       address pc = reloc->addr();
2027       install_post_call_nop_displacement(this, pc);
2028     }
2029   }
2030 
2031   if (virtual_call_data.length() > 0) {
2032     // We allocate a block of CompiledICData per nmethod so the GC can purge this faster.
2033     _compiled_ic_data = new CompiledICData[virtual_call_data.length()];
2034     CompiledICData* next_data = _compiled_ic_data;
2035 
2036     for (NativeMovConstReg* value : virtual_call_data) {
2037       value->set_data((intptr_t)next_data);
2038       next_data++;
2039     }
2040   }
2041 
2042   BarrierSetNMethod* bs_nm = BarrierSet::barrier_set()->barrier_set_nmethod();
2043   bs_nm->finalize_relocations(this);
2044 }
2045 
2046 void nmethod::make_deoptimized() {
2047   if (!Continuations::enabled()) {
2048     // Don't deopt this again.
2049     set_deoptimized_done();
2050     return;
2051   }
2052 
2053   assert(method() == nullptr || can_be_deoptimized(), "");
2054 
2055   CompiledICLocker ml(this);
2056   assert(CompiledICLocker::is_safe(this), "mt unsafe call");
2057 
2058   // If post call nops have been already patched, we can just bail-out.
2059   if (has_been_deoptimized()) {
2060     return;
2061   }
2062 
2063   ResourceMark rm;
2064   RelocIterator iter(this, oops_reloc_begin());
2065 
2066   // Assume there will be some calls to make deoptimized.
2067   MACOS_AARCH64_ONLY(os::thread_wx_enable_write());
2068 
2069   while (iter.next()) {
2070 
2071     switch (iter.type()) {
2072       case relocInfo::virtual_call_type: {
2073         CompiledIC *ic = CompiledIC_at(&iter);
2074         address pc = ic->end_of_call();
2075         NativePostCallNop* nop = nativePostCallNop_at(pc);
2076         if (nop != nullptr) {
2077           nop->make_deopt();
2078         }
2079         assert(NativeDeoptInstruction::is_deopt_at(pc), "check");
2080         break;
2081       }
2082       case relocInfo::static_call_type:
2083       case relocInfo::opt_virtual_call_type: {
2084         CompiledDirectCall *csc = CompiledDirectCall::at(iter.reloc());
2085         address pc = csc->end_of_call();
2086         NativePostCallNop* nop = nativePostCallNop_at(pc);
2087         //tty->print_cr(" - static pc %p", pc);
2088         if (nop != nullptr) {
2089           nop->make_deopt();
2090         }
2091         // We can't assert here, there are some calls to stubs / runtime
2092         // that have reloc data and doesn't have a post call NOP.
2093         //assert(NativeDeoptInstruction::is_deopt_at(pc), "check");
2094         break;
2095       }
2096       default:
2097         break;
2098     }
2099   }
2100   // Don't deopt this again.
2101   set_deoptimized_done();
2102 }
2103 
2104 void nmethod::verify_clean_inline_caches() {
2105   assert(CompiledICLocker::is_safe(this), "mt unsafe call");
2106 
2107   ResourceMark rm;
2108   RelocIterator iter(this, oops_reloc_begin());
2109   while(iter.next()) {
2110     switch(iter.type()) {
2111       case relocInfo::virtual_call_type: {
2112         CompiledIC *ic = CompiledIC_at(&iter);
2113         CodeBlob *cb = CodeCache::find_blob(ic->destination());
2114         assert(cb != nullptr, "destination not in CodeBlob?");
2115         nmethod* nm = cb->as_nmethod_or_null();
2116         if (nm != nullptr) {
2117           // Verify that inline caches pointing to bad nmethods are clean
2118           if (!nm->is_in_use() || nm->is_unloading()) {
2119             assert(ic->is_clean(), "IC should be clean");
2120           }
2121         }
2122         break;
2123       }
2124       case relocInfo::static_call_type:
2125       case relocInfo::opt_virtual_call_type: {
2126         CompiledDirectCall *cdc = CompiledDirectCall::at(iter.reloc());
2127         CodeBlob *cb = CodeCache::find_blob(cdc->destination());
2128         assert(cb != nullptr, "destination not in CodeBlob?");
2129         nmethod* nm = cb->as_nmethod_or_null();
2130         if (nm != nullptr) {
2131           // Verify that inline caches pointing to bad nmethods are clean
2132           if (!nm->is_in_use() || nm->is_unloading() || nm->method()->code() != nm) {
2133             assert(cdc->is_clean(), "IC should be clean");
2134           }
2135         }
2136         break;
2137       }
2138       default:
2139         break;
2140     }
2141   }
2142 }
2143 
2144 void nmethod::mark_as_maybe_on_stack() {
2145   MACOS_AARCH64_ONLY(os::thread_wx_enable_write());
2146   AtomicAccess::store(&_gc_epoch, CodeCache::gc_epoch());
2147 }
2148 
2149 bool nmethod::is_maybe_on_stack() {
2150   // If the condition below is true, it means that the nmethod was found to
2151   // be alive the previous completed marking cycle.
2152   return AtomicAccess::load(&_gc_epoch) >= CodeCache::previous_completed_gc_marking_cycle();
2153 }
2154 
2155 void nmethod::inc_decompile_count() {
2156   if (!is_compiled_by_c2()) {
2157     return;
2158   }
2159   // Could be gated by ProfileTraps, but do not bother...
2160   Method* m = method();
2161   if (m == nullptr)  return;
2162   MethodData* mdo = m->method_data();
2163   if (mdo == nullptr)  return;
2164   // There is a benign race here.  See comments in methodData.hpp.
2165   mdo->inc_decompile_count();
2166 }
2167 
2168 bool nmethod::try_transition(signed char new_state_int) {
2169   signed char new_state = new_state_int;
2170   assert_lock_strong(NMethodState_lock);
2171   signed char old_state = _state;
2172   if (old_state >= new_state) {
2173     // Ensure monotonicity of transitions.
2174     return false;
2175   }
2176   AtomicAccess::store(&_state, new_state);
2177   return true;
2178 }
2179 
2180 void nmethod::invalidate_osr_method() {
2181   assert(_entry_bci != InvocationEntryBci, "wrong kind of nmethod");
2182   // Remove from list of active nmethods
2183   if (method() != nullptr) {
2184     method()->method_holder()->remove_osr_nmethod(this);
2185   }
2186 }
2187 
2188 void nmethod::log_state_change(InvalidationReason invalidation_reason) const {
2189   if (LogCompilation) {
2190     if (xtty != nullptr) {
2191       ttyLocker ttyl;  // keep the following output all in one block
2192       xtty->begin_elem("make_not_entrant thread='%zu' reason='%s'",
2193                        os::current_thread_id(), invalidation_reason_to_string(invalidation_reason));
2194       log_identity(xtty);
2195       xtty->stamp();
2196       xtty->end_elem();
2197     }
2198   }
2199 
2200   ResourceMark rm;
2201   stringStream ss(NEW_RESOURCE_ARRAY(char, 256), 256);
2202   ss.print("made not entrant: %s", invalidation_reason_to_string(invalidation_reason));
2203 
2204   CompileTask::print_ul(this, ss.freeze());
2205   if (PrintCompilation) {
2206     print_on_with_msg(tty, ss.freeze());
2207   }
2208 }
2209 
2210 void nmethod::unlink_from_method() {
2211   if (method() != nullptr) {
2212     method()->unlink_code(this);
2213   }
2214 }
2215 
2216 // Invalidate code
2217 bool nmethod::make_not_entrant(InvalidationReason invalidation_reason) {
2218   // This can be called while the system is already at a safepoint which is ok
2219   NoSafepointVerifier nsv;
2220 
2221   if (is_unloading()) {
2222     // If the nmethod is unloading, then it is already not entrant through
2223     // the nmethod entry barriers. No need to do anything; GC will unload it.
2224     return false;
2225   }
2226 
2227   if (AtomicAccess::load(&_state) == not_entrant) {
2228     // Avoid taking the lock if already in required state.
2229     // This is safe from races because the state is an end-state,
2230     // which the nmethod cannot back out of once entered.
2231     // No need for fencing either.
2232     return false;
2233   }
2234 
2235   MACOS_AARCH64_ONLY(os::thread_wx_enable_write());
2236 
2237   {
2238     // Enter critical section.  Does not block for safepoint.
2239     ConditionalMutexLocker ml(NMethodState_lock, !NMethodState_lock->owned_by_self(), Mutex::_no_safepoint_check_flag);
2240 
2241     if (AtomicAccess::load(&_state) == not_entrant) {
2242       // another thread already performed this transition so nothing
2243       // to do, but return false to indicate this.
2244       return false;
2245     }
2246 
2247     if (is_osr_method()) {
2248       // This logic is equivalent to the logic below for patching the
2249       // verified entry point of regular methods.
2250       // this effectively makes the osr nmethod not entrant
2251       invalidate_osr_method();
2252     } else {
2253       // The caller can be calling the method statically or through an inline
2254       // cache call.
2255       BarrierSet::barrier_set()->barrier_set_nmethod()->make_not_entrant(this);
2256     }
2257 
2258     if (update_recompile_counts()) {
2259       // Mark the method as decompiled.
2260       inc_decompile_count();
2261     }
2262 
2263     BarrierSetNMethod* bs_nm = BarrierSet::barrier_set()->barrier_set_nmethod();
2264     if (bs_nm == nullptr || !bs_nm->supports_entry_barrier(this)) {
2265       // If nmethod entry barriers are not supported, we won't mark
2266       // nmethods as on-stack when they become on-stack. So we
2267       // degrade to a less accurate flushing strategy, for now.
2268       mark_as_maybe_on_stack();
2269     }
2270 
2271     // Change state
2272     bool success = try_transition(not_entrant);
2273     assert(success, "Transition can't fail");
2274 
2275     // Log the transition once
2276     log_state_change(invalidation_reason);
2277 
2278     // Remove nmethod from method.
2279     unlink_from_method();
2280 
2281   } // leave critical region under NMethodState_lock
2282 
2283 #ifdef ASSERT
2284   if (is_osr_method() && method() != nullptr) {
2285     // Make sure osr nmethod is invalidated, i.e. not on the list
2286     bool found = method()->method_holder()->remove_osr_nmethod(this);
2287     assert(!found, "osr nmethod should have been invalidated");
2288   }
2289 #endif
2290 
2291   return true;
2292 }
2293 
2294 // For concurrent GCs, there must be a handshake between unlink and flush
2295 void nmethod::unlink() {
2296   if (is_unlinked()) {
2297     // Already unlinked.
2298     return;
2299   }
2300 
2301   flush_dependencies();
2302 
2303   // unlink_from_method will take the NMethodState_lock.
2304   // In this case we don't strictly need it when unlinking nmethods from
2305   // the Method, because it is only concurrently unlinked by
2306   // the entry barrier, which acquires the per nmethod lock.
2307   unlink_from_method();
2308 
2309   if (is_osr_method()) {
2310     invalidate_osr_method();
2311   }
2312 
2313   // Post before flushing as jmethodID is being used
2314   post_compiled_method_unload();
2315 
2316   // Register for flushing when it is safe. For concurrent class unloading,
2317   // that would be after the unloading handshake, and for STW class unloading
2318   // that would be when getting back to the VM thread.
2319   ClassUnloadingContext::context()->register_unlinked_nmethod(this);
2320 }
2321 
2322 void nmethod::purge(bool unregister_nmethod) {
2323 
2324   MutexLocker ml(CodeCache_lock, Mutex::_no_safepoint_check_flag);
2325 
2326   // completely deallocate this method
2327   Events::log_nmethod_flush(Thread::current(), "flushing %s nmethod " INTPTR_FORMAT, is_osr_method() ? "osr" : "", p2i(this));
2328 
2329   LogTarget(Debug, codecache) lt;
2330   if (lt.is_enabled()) {
2331     ResourceMark rm;
2332     LogStream ls(lt);
2333     const char* method_name = method()->name()->as_C_string();
2334     const size_t codecache_capacity = CodeCache::capacity()/1024;
2335     const size_t codecache_free_space = CodeCache::unallocated_capacity(CodeCache::get_code_blob_type(this))/1024;
2336     ls.print("Flushing nmethod %6d/" INTPTR_FORMAT ", level=%d, osr=%d, cold=%d, epoch=" UINT64_FORMAT ", cold_count=" UINT64_FORMAT ". "
2337               "Cache capacity: %zuKb, free space: %zuKb. method %s (%s)",
2338               _compile_id, p2i(this), _comp_level, is_osr_method(), is_cold(), _gc_epoch, CodeCache::cold_gc_count(),
2339               codecache_capacity, codecache_free_space, method_name, compiler_name());
2340   }
2341 
2342   // We need to deallocate any ExceptionCache data.
2343   // Note that we do not need to grab the nmethod lock for this, it
2344   // better be thread safe if we're disposing of it!
2345   ExceptionCache* ec = exception_cache();
2346   while(ec != nullptr) {
2347     ExceptionCache* next = ec->next();
2348     delete ec;
2349     ec = next;
2350   }
2351   if (_pc_desc_container != nullptr) {
2352     delete _pc_desc_container;
2353   }
2354   delete[] _compiled_ic_data;
2355 
2356   if (_immutable_data != blob_end()) {
2357     // Free memory if this was the last nmethod referencing immutable data
2358     if (dec_immutable_data_ref_count() == 0) {
2359       os::free(_immutable_data);
2360     }
2361 
2362     _immutable_data = blob_end(); // Valid not null address
2363   }
2364 
2365   if (unregister_nmethod) {
2366     Universe::heap()->unregister_nmethod(this);
2367   }
2368 
2369 #ifdef COMPILER2
2370   HotCodeCollector::unregister_nmethod(this);
2371 #endif // COMPILER2
2372 
2373   CodeCache::unregister_old_nmethod(this);
2374 
2375   CodeBlob::purge();
2376 }
2377 
2378 oop nmethod::oop_at(int index) const {
2379   if (index == 0) {
2380     return nullptr;
2381   }
2382 
2383   BarrierSetNMethod* bs_nm = BarrierSet::barrier_set()->barrier_set_nmethod();
2384   return bs_nm->oop_load_no_keepalive(this, index);
2385 }
2386 
2387 oop nmethod::oop_at_phantom(int index) const {
2388   if (index == 0) {
2389     return nullptr;
2390   }
2391 
2392   BarrierSetNMethod* bs_nm = BarrierSet::barrier_set()->barrier_set_nmethod();
2393   return bs_nm->oop_load_phantom(this, index);
2394 }
2395 
2396 //
2397 // Notify all classes this nmethod is dependent on that it is no
2398 // longer dependent.
2399 
2400 void nmethod::flush_dependencies() {
2401   if (!has_flushed_dependencies()) {
2402     set_has_flushed_dependencies(true);
2403     for (Dependencies::DepStream deps(this); deps.next(); ) {
2404       if (deps.type() == Dependencies::call_site_target_value) {
2405         // CallSite dependencies are managed on per-CallSite instance basis.
2406         oop call_site = deps.argument_oop(0);
2407         MethodHandles::clean_dependency_context(call_site);
2408       } else {
2409         InstanceKlass* ik = deps.context_type();
2410         if (ik == nullptr) {
2411           continue;  // ignore things like evol_method
2412         }
2413         // During GC liveness of dependee determines class that needs to be updated.
2414         // The GC may clean dependency contexts concurrently and in parallel.
2415         ik->clean_dependency_context();
2416       }
2417     }
2418   }
2419 }
2420 
2421 void nmethod::post_compiled_method(CompileTask* task) {
2422   task->mark_success();
2423   task->set_nm_content_size(content_size());
2424   task->set_nm_insts_size(insts_size());
2425   task->set_nm_total_size(total_size());
2426 
2427   // JVMTI -- compiled method notification (must be done outside lock)
2428   post_compiled_method_load_event();
2429 
2430   if (CompilationLog::log() != nullptr) {
2431     CompilationLog::log()->log_nmethod(JavaThread::current(), this);
2432   }
2433 
2434   const DirectiveSet* directive = task->directive();
2435   maybe_print_nmethod(directive);
2436 }
2437 
2438 #if INCLUDE_CDS
2439 static GrowableArrayCHeap<nmethod*, mtClassShared>* _delayed_compiled_method_load_events = nullptr;
2440 
2441 void nmethod::add_delayed_compiled_method_load_event(nmethod* nm) {
2442   precond(CDSConfig::is_using_aot_linked_classes());
2443   precond(!ServiceThread::has_started());
2444 
2445   // We are still in single threaded stage of VM bootstrap. No need to lock.
2446   if (_delayed_compiled_method_load_events == nullptr) {
2447     _delayed_compiled_method_load_events = new GrowableArrayCHeap<nmethod*, mtClassShared>();
2448   }
2449   _delayed_compiled_method_load_events->append(nm);
2450 }
2451 
2452 void nmethod::post_delayed_compiled_method_load_events() {
2453   precond(ServiceThread::has_started());
2454   if (_delayed_compiled_method_load_events != nullptr) {
2455     for (int i = 0; i < _delayed_compiled_method_load_events->length(); i++) {
2456       nmethod* nm = _delayed_compiled_method_load_events->at(i);
2457       nm->post_compiled_method_load_event();
2458     }
2459     delete _delayed_compiled_method_load_events;
2460     _delayed_compiled_method_load_events = nullptr;
2461   }
2462 }
2463 #endif
2464 
2465 // ------------------------------------------------------------------
2466 // post_compiled_method_load_event
2467 // new method for install_code() path
2468 // Transfer information from compilation to jvmti
2469 void nmethod::post_compiled_method_load_event(JvmtiThreadState* state) {
2470 #if INCLUDE_CDS
2471   if (!ServiceThread::has_started()) {
2472     // With AOT-linked classes, we could compile wrappers for native methods before the
2473     // ServiceThread has been started, so we must delay the events to be posted later.
2474     assert(state == nullptr, "must be");
2475     add_delayed_compiled_method_load_event(this);
2476     return;
2477   }
2478 #endif
2479 
2480   // This is a bad time for a safepoint.  We don't want
2481   // this nmethod to get unloaded while we're queueing the event.
2482   NoSafepointVerifier nsv;
2483 
2484   Method* m = method();
2485   HOTSPOT_COMPILED_METHOD_LOAD(
2486       (char *) m->klass_name()->bytes(),
2487       m->klass_name()->utf8_length(),
2488       (char *) m->name()->bytes(),
2489       m->name()->utf8_length(),
2490       (char *) m->signature()->bytes(),
2491       m->signature()->utf8_length(),
2492       insts_begin(), insts_size());
2493 
2494 
2495   if (JvmtiExport::should_post_compiled_method_load()) {
2496     // Only post unload events if load events are found.
2497     set_load_reported();
2498     // If a JavaThread hasn't been passed in, let the Service thread
2499     // (which is a real Java thread) post the event
2500     JvmtiDeferredEvent event = JvmtiDeferredEvent::compiled_method_load_event(this);
2501     if (state == nullptr) {
2502       // Execute any barrier code for this nmethod as if it's called, since
2503       // keeping it alive looks like stack walking.
2504       run_nmethod_entry_barrier();
2505       ServiceThread::enqueue_deferred_event(&event);
2506     } else {
2507       // This enters the nmethod barrier outside in the caller.
2508       state->enqueue_event(&event);
2509     }
2510   }
2511 }
2512 
2513 void nmethod::post_compiled_method_unload() {
2514   assert(_method != nullptr, "just checking");
2515   DTRACE_METHOD_UNLOAD_PROBE(method());
2516 
2517   // If a JVMTI agent has enabled the CompiledMethodUnload event then
2518   // post the event. The Method* will not be valid when this is freed.
2519 
2520   // Don't bother posting the unload if the load event wasn't posted.
2521   if (load_reported() && JvmtiExport::should_post_compiled_method_unload()) {
2522     JvmtiDeferredEvent event =
2523       JvmtiDeferredEvent::compiled_method_unload_event(
2524           method()->jmethod_id(), insts_begin());
2525     ServiceThread::enqueue_deferred_event(&event);
2526   }
2527 }
2528 
2529 // Iterate over metadata calling this function.   Used by RedefineClasses
2530 void nmethod::metadata_do(MetadataClosure* f) {
2531   {
2532     // Visit all immediate references that are embedded in the instruction stream.
2533     RelocIterator iter(this, oops_reloc_begin());
2534     while (iter.next()) {
2535       if (iter.type() == relocInfo::metadata_type) {
2536         metadata_Relocation* r = iter.metadata_reloc();
2537         // In this metadata, we must only follow those metadatas directly embedded in
2538         // the code.  Other metadatas (oop_index>0) are seen as part of
2539         // the metadata section below.
2540         assert(1 == (r->metadata_is_immediate()) +
2541                (r->metadata_addr() >= metadata_begin() && r->metadata_addr() < metadata_end()),
2542                "metadata must be found in exactly one place");
2543         if (r->metadata_is_immediate() && r->metadata_value() != nullptr) {
2544           Metadata* md = r->metadata_value();
2545           if (md != _method) f->do_metadata(md);
2546         }
2547       } else if (iter.type() == relocInfo::virtual_call_type) {
2548         // Check compiledIC holders associated with this nmethod
2549         ResourceMark rm;
2550         CompiledIC *ic = CompiledIC_at(&iter);
2551         ic->metadata_do(f);
2552       }
2553     }
2554   }
2555 
2556   // Visit the metadata section
2557   for (Metadata** p = metadata_begin(); p < metadata_end(); p++) {
2558     if (*p == Universe::non_oop_word() || *p == nullptr)  continue;  // skip non-oops
2559     Metadata* md = *p;
2560     f->do_metadata(md);
2561   }
2562 
2563   // Visit metadata not embedded in the other places.
2564   if (_method != nullptr) f->do_metadata(_method);
2565 }
2566 
2567 // Heuristic for nuking nmethods even though their oops are live.
2568 // Main purpose is to reduce code cache pressure and get rid of
2569 // nmethods that don't seem to be all that relevant any longer.
2570 bool nmethod::is_cold() {
2571   if (!MethodFlushing || is_not_installed()) {
2572     // No heuristic unloading at all
2573     return false;
2574   }
2575 
2576   if (!is_maybe_on_stack() && is_not_entrant()) {
2577     // Not entrant nmethods that are not on any stack can just
2578     // be removed
2579     return true;
2580   }
2581 
2582   BarrierSetNMethod* bs_nm = BarrierSet::barrier_set()->barrier_set_nmethod();
2583   if (bs_nm == nullptr || !bs_nm->supports_entry_barrier(this)) {
2584     // On platforms that don't support nmethod entry barriers, we can't
2585     // trust the temporal aspect of the gc epochs. So we can't detect
2586     // cold nmethods on such platforms.
2587     return false;
2588   }
2589 
2590   if (!UseCodeCacheFlushing) {
2591     // Bail out if we don't heuristically remove nmethods
2592     return false;
2593   }
2594 
2595   // Other code can be phased out more gradually after N GCs
2596   return CodeCache::previous_completed_gc_marking_cycle() > _gc_epoch + 2 * CodeCache::cold_gc_count();
2597 }
2598 
2599 // The _is_unloading_state encodes a tuple comprising the unloading cycle
2600 // and the result of IsUnloadingBehaviour::is_unloading() for that cycle.
2601 // This is the bit layout of the _is_unloading_state byte: 00000CCU
2602 // CC refers to the cycle, which has 2 bits, and U refers to the result of
2603 // IsUnloadingBehaviour::is_unloading() for that unloading cycle.
2604 
2605 class IsUnloadingState: public AllStatic {
2606   static const uint8_t _is_unloading_mask = 1;
2607   static const uint8_t _is_unloading_shift = 0;
2608   static const uint8_t _unloading_cycle_mask = 6;
2609   static const uint8_t _unloading_cycle_shift = 1;
2610 
2611   static uint8_t set_is_unloading(uint8_t state, bool value) {
2612     state &= (uint8_t)~_is_unloading_mask;
2613     if (value) {
2614       state |= 1 << _is_unloading_shift;
2615     }
2616     assert(is_unloading(state) == value, "unexpected unloading cycle overflow");
2617     return state;
2618   }
2619 
2620   static uint8_t set_unloading_cycle(uint8_t state, uint8_t value) {
2621     state &= (uint8_t)~_unloading_cycle_mask;
2622     state |= (uint8_t)(value << _unloading_cycle_shift);
2623     assert(unloading_cycle(state) == value, "unexpected unloading cycle overflow");
2624     return state;
2625   }
2626 
2627 public:
2628   static bool is_unloading(uint8_t state) { return (state & _is_unloading_mask) >> _is_unloading_shift == 1; }
2629   static uint8_t unloading_cycle(uint8_t state) { return (state & _unloading_cycle_mask) >> _unloading_cycle_shift; }
2630 
2631   static uint8_t create(bool is_unloading, uint8_t unloading_cycle) {
2632     uint8_t state = 0;
2633     state = set_is_unloading(state, is_unloading);
2634     state = set_unloading_cycle(state, unloading_cycle);
2635     return state;
2636   }
2637 };
2638 
2639 bool nmethod::is_unloading() {
2640   uint8_t state = AtomicAccess::load(&_is_unloading_state);
2641   bool state_is_unloading = IsUnloadingState::is_unloading(state);
2642   if (state_is_unloading) {
2643     return true;
2644   }
2645   uint8_t state_unloading_cycle = IsUnloadingState::unloading_cycle(state);
2646   uint8_t current_cycle = CodeCache::unloading_cycle();
2647   if (state_unloading_cycle == current_cycle) {
2648     return false;
2649   }
2650 
2651   // The IsUnloadingBehaviour is responsible for calculating if the nmethod
2652   // should be unloaded. This can be either because there is a dead oop,
2653   // or because is_cold() heuristically determines it is time to unload.
2654   state_unloading_cycle = current_cycle;
2655   state_is_unloading = IsUnloadingBehaviour::is_unloading(this);
2656   uint8_t new_state = IsUnloadingState::create(state_is_unloading, state_unloading_cycle);
2657 
2658   MACOS_AARCH64_ONLY(os::thread_wx_enable_write());
2659 
2660   // Note that if an nmethod has dead oops, everyone will agree that the
2661   // nmethod is_unloading. However, the is_cold heuristics can yield
2662   // different outcomes, so we guard the computed result with a CAS
2663   // to ensure all threads have a shared view of whether an nmethod
2664   // is_unloading or not.
2665   uint8_t found_state = AtomicAccess::cmpxchg(&_is_unloading_state, state, new_state, memory_order_relaxed);
2666 
2667   if (found_state == state) {
2668     // First to change state, we win
2669     return state_is_unloading;
2670   } else {
2671     // State already set, so use it
2672     return IsUnloadingState::is_unloading(found_state);
2673   }
2674 }
2675 
2676 void nmethod::clear_unloading_state() {
2677   uint8_t state = IsUnloadingState::create(false, CodeCache::unloading_cycle());
2678   AtomicAccess::store(&_is_unloading_state, state);
2679 }
2680 
2681 
2682 // This is called at the end of the strong tracing/marking phase of a
2683 // GC to unload an nmethod if it contains otherwise unreachable
2684 // oops or is heuristically found to be not important.
2685 void nmethod::do_unloading(bool unloading_occurred) {
2686   // Make sure the oop's ready to receive visitors
2687   if (is_unloading()) {
2688     unlink();
2689   } else {
2690     unload_nmethod_caches(unloading_occurred);
2691     BarrierSetNMethod* bs_nm = BarrierSet::barrier_set()->barrier_set_nmethod();
2692     if (bs_nm != nullptr) {
2693       bs_nm->disarm(this);
2694     }
2695   }
2696 }
2697 
2698 void nmethod::oops_do(OopClosure* f) {
2699   // Prevent extra code cache walk for platforms that don't have immediate oops.
2700   if (relocInfo::mustIterateImmediateOopsInCode()) {
2701     RelocIterator iter(this, oops_reloc_begin());
2702 
2703     while (iter.next()) {
2704       if (iter.type() == relocInfo::oop_type ) {
2705         oop_Relocation* r = iter.oop_reloc();
2706         // In this loop, we must only follow those oops directly embedded in
2707         // the code.  Other oops (oop_index>0) are seen as part of scopes_oops.
2708         assert(1 == (r->oop_is_immediate()) +
2709                (r->oop_addr() >= oops_begin() && r->oop_addr() < oops_end()),
2710                "oop must be found in exactly one place");
2711         if (r->oop_is_immediate() && r->oop_value() != nullptr) {
2712           f->do_oop(r->oop_addr());
2713         }
2714       }
2715     }
2716   }
2717 
2718   // Scopes
2719   // This includes oop constants not inlined in the code stream.
2720   for (oop* p = oops_begin(); p < oops_end(); p++) {
2721     if (*p == Universe::non_oop_word())  continue;  // skip non-oops
2722     f->do_oop(p);
2723   }
2724 }
2725 
2726 void nmethod::follow_nmethod(OopIterateClosure* cl) {
2727   // Process oops in the nmethod
2728   oops_do(cl);
2729 
2730   // CodeCache unloading support
2731   mark_as_maybe_on_stack();
2732 
2733   BarrierSetNMethod* bs_nm = BarrierSet::barrier_set()->barrier_set_nmethod();
2734   bs_nm->disarm(this);
2735 
2736   // There's an assumption made that this function is not used by GCs that
2737   // relocate objects, and therefore we don't call fix_oop_relocations.
2738 }
2739 
2740 nmethod* volatile nmethod::_oops_do_mark_nmethods;
2741 
2742 void nmethod::oops_do_log_change(const char* state) {
2743   LogTarget(Trace, gc, nmethod) lt;
2744   if (lt.is_enabled()) {
2745     LogStream ls(lt);
2746     CompileTask::print(&ls, this, state, true /* short_form */);
2747   }
2748 }
2749 
2750 bool nmethod::oops_do_try_claim() {
2751   if (oops_do_try_claim_weak_request()) {
2752     nmethod* result = oops_do_try_add_to_list_as_weak_done();
2753     assert(result == nullptr, "adding to global list as weak done must always succeed.");
2754     return true;
2755   }
2756   return false;
2757 }
2758 
2759 bool nmethod::oops_do_try_claim_weak_request() {
2760   assert(SafepointSynchronize::is_at_safepoint(), "only at safepoint");
2761 
2762   if ((_oops_do_mark_link == nullptr) &&
2763       (AtomicAccess::replace_if_null(&_oops_do_mark_link, mark_link(this, claim_weak_request_tag)))) {
2764     oops_do_log_change("oops_do, mark weak request");
2765     return true;
2766   }
2767   return false;
2768 }
2769 
2770 void nmethod::oops_do_set_strong_done(nmethod* old_head) {
2771   _oops_do_mark_link = mark_link(old_head, claim_strong_done_tag);
2772 }
2773 
2774 nmethod::oops_do_mark_link* nmethod::oops_do_try_claim_strong_done() {
2775   assert(SafepointSynchronize::is_at_safepoint(), "only at safepoint");
2776 
2777   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));
2778   if (old_next == nullptr) {
2779     oops_do_log_change("oops_do, mark strong done");
2780   }
2781   return old_next;
2782 }
2783 
2784 nmethod::oops_do_mark_link* nmethod::oops_do_try_add_strong_request(nmethod::oops_do_mark_link* next) {
2785   assert(SafepointSynchronize::is_at_safepoint(), "only at safepoint");
2786   assert(next == mark_link(this, claim_weak_request_tag), "Should be claimed as weak");
2787 
2788   oops_do_mark_link* old_next = AtomicAccess::cmpxchg(&_oops_do_mark_link, next, mark_link(this, claim_strong_request_tag));
2789   if (old_next == next) {
2790     oops_do_log_change("oops_do, mark strong request");
2791   }
2792   return old_next;
2793 }
2794 
2795 bool nmethod::oops_do_try_claim_weak_done_as_strong_done(nmethod::oops_do_mark_link* next) {
2796   assert(SafepointSynchronize::is_at_safepoint(), "only at safepoint");
2797   assert(extract_state(next) == claim_weak_done_tag, "Should be claimed as weak done");
2798 
2799   oops_do_mark_link* old_next = AtomicAccess::cmpxchg(&_oops_do_mark_link, next, mark_link(extract_nmethod(next), claim_strong_done_tag));
2800   if (old_next == next) {
2801     oops_do_log_change("oops_do, mark weak done -> mark strong done");
2802     return true;
2803   }
2804   return false;
2805 }
2806 
2807 nmethod* nmethod::oops_do_try_add_to_list_as_weak_done() {
2808   assert(SafepointSynchronize::is_at_safepoint(), "only at safepoint");
2809 
2810   assert(extract_state(_oops_do_mark_link) == claim_weak_request_tag ||
2811          extract_state(_oops_do_mark_link) == claim_strong_request_tag,
2812          "must be but is nmethod " PTR_FORMAT " %u", p2i(extract_nmethod(_oops_do_mark_link)), extract_state(_oops_do_mark_link));
2813 
2814   nmethod* old_head = AtomicAccess::xchg(&_oops_do_mark_nmethods, this);
2815   // Self-loop if needed.
2816   if (old_head == nullptr) {
2817     old_head = this;
2818   }
2819   // Try to install end of list and weak done tag.
2820   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)) {
2821     oops_do_log_change("oops_do, mark weak done");
2822     return nullptr;
2823   } else {
2824     return old_head;
2825   }
2826 }
2827 
2828 void nmethod::oops_do_add_to_list_as_strong_done() {
2829   assert(SafepointSynchronize::is_at_safepoint(), "only at safepoint");
2830 
2831   nmethod* old_head = AtomicAccess::xchg(&_oops_do_mark_nmethods, this);
2832   // Self-loop if needed.
2833   if (old_head == nullptr) {
2834     old_head = this;
2835   }
2836   assert(_oops_do_mark_link == mark_link(this, claim_strong_done_tag), "must be but is nmethod " PTR_FORMAT " state %u",
2837          p2i(extract_nmethod(_oops_do_mark_link)), extract_state(_oops_do_mark_link));
2838 
2839   oops_do_set_strong_done(old_head);
2840 }
2841 
2842 void nmethod::oops_do_process_weak(OopsDoProcessor* p) {
2843   if (!oops_do_try_claim_weak_request()) {
2844     // Failed to claim for weak processing.
2845     oops_do_log_change("oops_do, mark weak request fail");
2846     return;
2847   }
2848 
2849   p->do_regular_processing(this);
2850 
2851   nmethod* old_head = oops_do_try_add_to_list_as_weak_done();
2852   if (old_head == nullptr) {
2853     return;
2854   }
2855   oops_do_log_change("oops_do, mark weak done fail");
2856   // Adding to global list failed, another thread added a strong request.
2857   assert(extract_state(_oops_do_mark_link) == claim_strong_request_tag,
2858          "must be but is %u", extract_state(_oops_do_mark_link));
2859 
2860   oops_do_log_change("oops_do, mark weak request -> mark strong done");
2861 
2862   oops_do_set_strong_done(old_head);
2863   // Do missing strong processing.
2864   p->do_remaining_strong_processing(this);
2865 }
2866 
2867 void nmethod::oops_do_process_strong(OopsDoProcessor* p) {
2868   oops_do_mark_link* next_raw = oops_do_try_claim_strong_done();
2869   if (next_raw == nullptr) {
2870     p->do_regular_processing(this);
2871     oops_do_add_to_list_as_strong_done();
2872     return;
2873   }
2874   // Claim failed. Figure out why and handle it.
2875   if (oops_do_has_weak_request(next_raw)) {
2876     oops_do_mark_link* old = next_raw;
2877     // Claim failed because being weak processed (state == "weak request").
2878     // Try to request deferred strong processing.
2879     next_raw = oops_do_try_add_strong_request(old);
2880     if (next_raw == old) {
2881       // Successfully requested deferred strong processing.
2882       return;
2883     }
2884     // Failed because of a concurrent transition. No longer in "weak request" state.
2885   }
2886   if (oops_do_has_any_strong_state(next_raw)) {
2887     // Already claimed for strong processing or requested for such.
2888     return;
2889   }
2890   if (oops_do_try_claim_weak_done_as_strong_done(next_raw)) {
2891     // Successfully claimed "weak done" as "strong done". Do the missing marking.
2892     p->do_remaining_strong_processing(this);
2893     return;
2894   }
2895   // Claim failed, some other thread got it.
2896 }
2897 
2898 void nmethod::oops_do_marking_prologue() {
2899   assert_at_safepoint();
2900 
2901   log_trace(gc, nmethod)("oops_do_marking_prologue");
2902   assert(_oops_do_mark_nmethods == nullptr, "must be empty");
2903 }
2904 
2905 void nmethod::oops_do_marking_epilogue() {
2906   assert_at_safepoint();
2907 
2908   nmethod* next = _oops_do_mark_nmethods;
2909   _oops_do_mark_nmethods = nullptr;
2910   if (next != nullptr) {
2911     nmethod* cur;
2912     do {
2913       cur = next;
2914       next = extract_nmethod(cur->_oops_do_mark_link);
2915       cur->_oops_do_mark_link = nullptr;
2916       DEBUG_ONLY(cur->verify_oop_relocations());
2917 
2918       LogTarget(Trace, gc, nmethod) lt;
2919       if (lt.is_enabled()) {
2920         LogStream ls(lt);
2921         CompileTask::print(&ls, cur, "oops_do, unmark", /*short_form:*/ true);
2922       }
2923       // End if self-loop has been detected.
2924     } while (cur != next);
2925   }
2926   log_trace(gc, nmethod)("oops_do_marking_epilogue");
2927 }
2928 
2929 inline bool includes(void* p, void* from, void* to) {
2930   return from <= p && p < to;
2931 }
2932 
2933 
2934 void nmethod::copy_scopes_pcs(PcDesc* pcs, int count) {
2935   assert(count >= 2, "must be sentinel values, at least");
2936 
2937 #ifdef ASSERT
2938   // must be sorted and unique; we do a binary search in find_pc_desc()
2939   int prev_offset = pcs[0].pc_offset();
2940   assert(prev_offset == PcDesc::lower_offset_limit,
2941          "must start with a sentinel");
2942   for (int i = 1; i < count; i++) {
2943     int this_offset = pcs[i].pc_offset();
2944     assert(this_offset > prev_offset, "offsets must be sorted");
2945     prev_offset = this_offset;
2946   }
2947   assert(prev_offset == PcDesc::upper_offset_limit,
2948          "must end with a sentinel");
2949 #endif //ASSERT
2950 
2951   int size = count * sizeof(PcDesc);
2952   assert(scopes_pcs_size() >= size, "oob");
2953   memcpy(scopes_pcs_begin(), pcs, size);
2954 
2955   // Adjust the final sentinel downward.
2956   PcDesc* last_pc = &scopes_pcs_begin()[count-1];
2957   assert(last_pc->pc_offset() == PcDesc::upper_offset_limit, "sanity");
2958   last_pc->set_pc_offset(content_size() + 1);
2959   for (; last_pc + 1 < scopes_pcs_end(); last_pc += 1) {
2960     // Fill any rounding gaps with copies of the last record.
2961     last_pc[1] = last_pc[0];
2962   }
2963   // The following assert could fail if sizeof(PcDesc) is not
2964   // an integral multiple of oopSize (the rounding term).
2965   // If it fails, change the logic to always allocate a multiple
2966   // of sizeof(PcDesc), and fill unused words with copies of *last_pc.
2967   assert(last_pc + 1 == scopes_pcs_end(), "must match exactly");
2968 }
2969 
2970 void nmethod::copy_scopes_data(u_char* buffer, int size) {
2971   assert(scopes_data_size() >= size, "oob");
2972   memcpy(scopes_data_begin(), buffer, size);
2973 }
2974 
2975 #ifdef ASSERT
2976 static PcDesc* linear_search(int pc_offset, bool approximate, PcDesc* lower, PcDesc* upper) {
2977   PcDesc* res = nullptr;
2978   assert(lower != nullptr && lower->pc_offset() == PcDesc::lower_offset_limit,
2979          "must start with a sentinel");
2980   // lower + 1 to exclude initial sentinel
2981   for (PcDesc* p = lower + 1; p < upper; p++) {
2982     NOT_PRODUCT(--pc_nmethod_stats.pc_desc_tests);  // don't count this call to match_desc
2983     if (match_desc(p, pc_offset, approximate)) {
2984       if (res == nullptr) {
2985         res = p;
2986       } else {
2987         res = (PcDesc*) badAddress;
2988       }
2989     }
2990   }
2991   return res;
2992 }
2993 #endif
2994 
2995 
2996 #ifndef PRODUCT
2997 // Version of method to collect statistic
2998 PcDesc* PcDescContainer::find_pc_desc(address pc, bool approximate, address code_begin,
2999                                       PcDesc* lower, PcDesc* upper) {
3000   ++pc_nmethod_stats.pc_desc_queries;
3001   if (approximate) ++pc_nmethod_stats.pc_desc_approx;
3002 
3003   PcDesc* desc = _pc_desc_cache.last_pc_desc();
3004   assert(desc != nullptr, "PcDesc cache should be initialized already");
3005   if (desc->pc_offset() == (pc - code_begin)) {
3006     // Cached value matched
3007     ++pc_nmethod_stats.pc_desc_tests;
3008     ++pc_nmethod_stats.pc_desc_repeats;
3009     return desc;
3010   }
3011   return find_pc_desc_internal(pc, approximate, code_begin, lower, upper);
3012 }
3013 #endif
3014 
3015 // Finds a PcDesc with real-pc equal to "pc"
3016 PcDesc* PcDescContainer::find_pc_desc_internal(address pc, bool approximate, address code_begin,
3017                                                PcDesc* lower_incl, PcDesc* upper_incl) {
3018   if ((pc < code_begin) ||
3019       (pc - code_begin) >= (ptrdiff_t) PcDesc::upper_offset_limit) {
3020     return nullptr;  // PC is wildly out of range
3021   }
3022   int pc_offset = (int) (pc - code_begin);
3023 
3024   // Check the PcDesc cache if it contains the desired PcDesc
3025   // (This as an almost 100% hit rate.)
3026   PcDesc* res = _pc_desc_cache.find_pc_desc(pc_offset, approximate);
3027   if (res != nullptr) {
3028     assert(res == linear_search(pc_offset, approximate, lower_incl, upper_incl), "cache ok");
3029     return res;
3030   }
3031 
3032   // Fallback algorithm: quasi-linear search for the PcDesc
3033   // Find the last pc_offset less than the given offset.
3034   // The successor must be the required match, if there is a match at all.
3035   // (Use a fixed radix to avoid expensive affine pointer arithmetic.)
3036   PcDesc* lower = lower_incl;     // this is initial sentinel
3037   PcDesc* upper = upper_incl - 1; // exclude final sentinel
3038   if (lower >= upper)  return nullptr;  // no PcDescs at all
3039 
3040 #define assert_LU_OK \
3041   /* invariant on lower..upper during the following search: */ \
3042   assert(lower->pc_offset() <  pc_offset, "sanity"); \
3043   assert(upper->pc_offset() >= pc_offset, "sanity")
3044   assert_LU_OK;
3045 
3046   // Use the last successful return as a split point.
3047   PcDesc* mid = _pc_desc_cache.last_pc_desc();
3048   NOT_PRODUCT(++pc_nmethod_stats.pc_desc_searches);
3049   if (mid->pc_offset() < pc_offset) {
3050     lower = mid;
3051   } else {
3052     upper = mid;
3053   }
3054 
3055   // Take giant steps at first (4096, then 256, then 16, then 1)
3056   const int LOG2_RADIX = 4 /*smaller steps in debug mode:*/ DEBUG_ONLY(-1);
3057   const int RADIX = (1 << LOG2_RADIX);
3058   for (int step = (1 << (LOG2_RADIX*3)); step > 1; step >>= LOG2_RADIX) {
3059     while ((mid = lower + step) < upper) {
3060       assert_LU_OK;
3061       NOT_PRODUCT(++pc_nmethod_stats.pc_desc_searches);
3062       if (mid->pc_offset() < pc_offset) {
3063         lower = mid;
3064       } else {
3065         upper = mid;
3066         break;
3067       }
3068     }
3069     assert_LU_OK;
3070   }
3071 
3072   // Sneak up on the value with a linear search of length ~16.
3073   while (true) {
3074     assert_LU_OK;
3075     mid = lower + 1;
3076     NOT_PRODUCT(++pc_nmethod_stats.pc_desc_searches);
3077     if (mid->pc_offset() < pc_offset) {
3078       lower = mid;
3079     } else {
3080       upper = mid;
3081       break;
3082     }
3083   }
3084 #undef assert_LU_OK
3085 
3086   if (match_desc(upper, pc_offset, approximate)) {
3087     assert(upper == linear_search(pc_offset, approximate, lower_incl, upper_incl), "search mismatch");
3088     if (!Thread::current_in_asgct()) {
3089       // we don't want to modify the cache if we're in ASGCT
3090       // which is typically called in a signal handler
3091       _pc_desc_cache.add_pc_desc(upper);
3092     }
3093     return upper;
3094   } else {
3095     assert(nullptr == linear_search(pc_offset, approximate, lower_incl, upper_incl), "search mismatch");
3096     return nullptr;
3097   }
3098 }
3099 
3100 bool nmethod::check_dependency_on(DepChange& changes) {
3101   // What has happened:
3102   // 1) a new class dependee has been added
3103   // 2) dependee and all its super classes have been marked
3104   bool found_check = false;  // set true if we are upset
3105   for (Dependencies::DepStream deps(this); deps.next(); ) {
3106     // Evaluate only relevant dependencies.
3107     if (deps.spot_check_dependency_at(changes) != nullptr) {
3108       found_check = true;
3109       NOT_DEBUG(break);
3110     }
3111   }
3112   return found_check;
3113 }
3114 
3115 // Called from mark_for_deoptimization, when dependee is invalidated.
3116 bool nmethod::is_dependent_on_method(Method* dependee) {
3117   for (Dependencies::DepStream deps(this); deps.next(); ) {
3118     if (Dependencies::has_method_dep(deps.type())) {
3119       Method* method = deps.method_argument(0);
3120       if (method == dependee) return true;
3121     }
3122   }
3123   return false;
3124 }
3125 
3126 void nmethod_init() {
3127   // make sure you didn't forget to adjust the filler fields
3128   assert(sizeof(nmethod) % oopSize == 0, "nmethod size must be multiple of a word");
3129 }
3130 
3131 // -----------------------------------------------------------------------------
3132 // Verification
3133 
3134 class VerifyOopsClosure: public OopClosure {
3135   nmethod* _nm;
3136   bool     _ok;
3137 public:
3138   VerifyOopsClosure(nmethod* nm) : _nm(nm), _ok(true) { }
3139   bool ok() { return _ok; }
3140   virtual void do_oop(oop* p) {
3141     if (oopDesc::is_oop_or_null(*p)) return;
3142     // Print diagnostic information before calling print_nmethod().
3143     // Assertions therein might prevent call from returning.
3144     tty->print_cr("*** non-oop " PTR_FORMAT " found at " PTR_FORMAT " (offset %d)",
3145                   p2i(*p), p2i(p), (int)((intptr_t)p - (intptr_t)_nm));
3146     if (_ok) {
3147       _nm->print_nmethod(true);
3148       _ok = false;
3149     }
3150   }
3151   virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
3152 };
3153 
3154 class VerifyMetadataClosure: public MetadataClosure {
3155  public:
3156   void do_metadata(Metadata* md) {
3157     if (md->is_method()) {
3158       Method* method = (Method*)md;
3159       assert(!method->is_old(), "Should not be installing old methods");
3160     }
3161   }
3162 };
3163 
3164 
3165 void nmethod::verify() {
3166   if (is_not_entrant())
3167     return;
3168 
3169   // assert(oopDesc::is_oop(method()), "must be valid");
3170 
3171   ResourceMark rm;
3172 
3173   if (!CodeCache::contains(this)) {
3174     fatal("nmethod at " INTPTR_FORMAT " not in zone", p2i(this));
3175   }
3176 
3177   if(is_native_method() )
3178     return;
3179 
3180   nmethod* nm = CodeCache::find_nmethod(verified_entry_point());
3181   if (nm != this) {
3182     fatal("find_nmethod did not find this nmethod (" INTPTR_FORMAT ")", p2i(this));
3183   }
3184 
3185   for (PcDesc* p = scopes_pcs_begin(); p < scopes_pcs_end(); p++) {
3186     if (! p->verify(this)) {
3187       tty->print_cr("\t\tin nmethod at " INTPTR_FORMAT " (pcs)", p2i(this));
3188     }
3189   }
3190 
3191   VerifyOopsClosure voc(this);
3192   oops_do(&voc);
3193   assert(voc.ok(), "embedded oops must be OK");
3194   Universe::heap()->verify_nmethod(this);
3195 
3196   assert(_oops_do_mark_link == nullptr, "_oops_do_mark_link for %s should be nullptr but is " PTR_FORMAT,
3197          nm->method()->external_name(), p2i(_oops_do_mark_link));
3198   verify_scopes();
3199 
3200   CompiledICLocker nm_verify(this);
3201   VerifyMetadataClosure vmc;
3202   metadata_do(&vmc);
3203 }
3204 
3205 
3206 void nmethod::verify_interrupt_point(address call_site, bool is_inline_cache) {
3207 
3208   // Verify IC only when nmethod installation is finished.
3209   if (!is_not_installed()) {
3210     if (CompiledICLocker::is_safe(this)) {
3211       if (is_inline_cache) {
3212         CompiledIC_at(this, call_site);
3213       } else {
3214         CompiledDirectCall::at(call_site);
3215       }
3216     } else {
3217       CompiledICLocker ml_verify(this);
3218       if (is_inline_cache) {
3219         CompiledIC_at(this, call_site);
3220       } else {
3221         CompiledDirectCall::at(call_site);
3222       }
3223     }
3224   }
3225 
3226   HandleMark hm(Thread::current());
3227 
3228   PcDesc* pd = pc_desc_at(nativeCall_at(call_site)->return_address());
3229   assert(pd != nullptr, "PcDesc must exist");
3230   for (ScopeDesc* sd = new ScopeDesc(this, pd);
3231        !sd->is_top(); sd = sd->sender()) {
3232     sd->verify();
3233   }
3234 }
3235 
3236 void nmethod::verify_scopes() {
3237   if( !method() ) return;       // Runtime stubs have no scope
3238   if (method()->is_native()) return; // Ignore stub methods.
3239   // iterate through all interrupt point
3240   // and verify the debug information is valid.
3241   RelocIterator iter(this);
3242   while (iter.next()) {
3243     address stub = nullptr;
3244     switch (iter.type()) {
3245       case relocInfo::virtual_call_type:
3246         verify_interrupt_point(iter.addr(), true /* is_inline_cache */);
3247         break;
3248       case relocInfo::opt_virtual_call_type:
3249         stub = iter.opt_virtual_call_reloc()->static_stub();
3250         verify_interrupt_point(iter.addr(), false /* is_inline_cache */);
3251         break;
3252       case relocInfo::static_call_type:
3253         stub = iter.static_call_reloc()->static_stub();
3254         verify_interrupt_point(iter.addr(), false /* is_inline_cache */);
3255         break;
3256       case relocInfo::runtime_call_type:
3257       case relocInfo::runtime_call_w_cp_type: {
3258         address destination = iter.reloc()->value();
3259         // Right now there is no way to find out which entries support
3260         // an interrupt point.  It would be nice if we had this
3261         // information in a table.
3262         break;
3263       }
3264       default:
3265         break;
3266     }
3267     assert(stub == nullptr || stub_contains(stub), "static call stub outside stub section");
3268   }
3269 }
3270 
3271 
3272 // -----------------------------------------------------------------------------
3273 // Printing operations
3274 
3275 void nmethod::print_on_impl(outputStream* st) const {
3276   ResourceMark rm;
3277 
3278   st->print("Compiled method ");
3279 
3280   if (is_compiled_by_c1()) {
3281     st->print("(c1) ");
3282   } else if (is_compiled_by_c2()) {
3283     st->print("(c2) ");
3284   } else {
3285     st->print("(n/a) ");
3286   }
3287 
3288   print_on_with_msg(st, nullptr);
3289 
3290   if (WizardMode) {
3291     st->print("((nmethod*) " INTPTR_FORMAT ") ", p2i(this));
3292     st->print(" for method " INTPTR_FORMAT , p2i(method()));
3293     st->print(" { ");
3294     st->print_cr("%s ", state());
3295     st->print_cr("}:");
3296   }
3297   if (size              () > 0) st->print_cr(" total in heap  [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
3298                                              p2i(this),
3299                                              p2i(this) + size(),
3300                                              size());
3301   if (consts_size       () > 0) st->print_cr(" constants      [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
3302                                              p2i(consts_begin()),
3303                                              p2i(consts_end()),
3304                                              consts_size());
3305   if (insts_size        () > 0) st->print_cr(" main code      [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
3306                                              p2i(insts_begin()),
3307                                              p2i(insts_end()),
3308                                              insts_size());
3309   if (stub_size         () > 0) st->print_cr(" stub code      [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
3310                                              p2i(stub_begin()),
3311                                              p2i(stub_end()),
3312                                              stub_size());
3313   if (oops_size         () > 0) st->print_cr(" oops           [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
3314                                              p2i(oops_begin()),
3315                                              p2i(oops_end()),
3316                                              oops_size());
3317   if (mutable_data_size () > 0) st->print_cr(" mutable data   [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
3318                                              p2i(mutable_data_begin()),
3319                                              p2i(mutable_data_end()),
3320                                              mutable_data_size());
3321   if (relocation_size   () > 0) st->print_cr(" relocation     [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
3322                                              p2i(relocation_begin()),
3323                                              p2i(relocation_end()),
3324                                              relocation_size());
3325   if (metadata_size     () > 0) st->print_cr(" metadata       [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
3326                                              p2i(metadata_begin()),
3327                                              p2i(metadata_end()),
3328                                              metadata_size());
3329   if (immutable_data_size() > 0) st->print_cr(" immutable data [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
3330                                              p2i(immutable_data_begin()),
3331                                              p2i(immutable_data_end()),
3332                                              immutable_data_size());
3333   if (dependencies_size () > 0) st->print_cr(" dependencies   [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
3334                                              p2i(dependencies_begin()),
3335                                              p2i(dependencies_end()),
3336                                              dependencies_size());
3337   if (nul_chk_table_size() > 0) st->print_cr(" nul chk table  [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
3338                                              p2i(nul_chk_table_begin()),
3339                                              p2i(nul_chk_table_end()),
3340                                              nul_chk_table_size());
3341   if (handler_table_size() > 0) st->print_cr(" handler table  [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
3342                                              p2i(handler_table_begin()),
3343                                              p2i(handler_table_end()),
3344                                              handler_table_size());
3345   if (scopes_pcs_size   () > 0) st->print_cr(" scopes pcs     [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
3346                                              p2i(scopes_pcs_begin()),
3347                                              p2i(scopes_pcs_end()),
3348                                              scopes_pcs_size());
3349   if (scopes_data_size  () > 0) st->print_cr(" scopes data    [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
3350                                              p2i(scopes_data_begin()),
3351                                              p2i(scopes_data_end()),
3352                                              scopes_data_size());
3353 }
3354 
3355 void nmethod::print_code() {
3356   ResourceMark m;
3357   ttyLocker ttyl;
3358   // Call the specialized decode method of this class.
3359   decode(tty);
3360 }
3361 
3362 #ifndef PRODUCT  // called InstanceKlass methods are available only then. Declared as PRODUCT_RETURN
3363 
3364 void nmethod::print_dependencies_on(outputStream* out) {
3365   ResourceMark rm;
3366   stringStream st;
3367   st.print_cr("Dependencies:");
3368   for (Dependencies::DepStream deps(this); deps.next(); ) {
3369     deps.print_dependency(&st);
3370     InstanceKlass* ctxk = deps.context_type();
3371     if (ctxk != nullptr) {
3372       if (ctxk->is_dependent_nmethod(this)) {
3373         st.print_cr("   [nmethod<=klass]%s", ctxk->external_name());
3374       }
3375     }
3376     deps.log_dependency();  // put it into the xml log also
3377   }
3378   out->print_raw(st.as_string());
3379 }
3380 #endif
3381 
3382 #if defined(SUPPORT_DATA_STRUCTS)
3383 
3384 // Print the oops from the underlying CodeBlob.
3385 void nmethod::print_oops(outputStream* st) {
3386   ResourceMark m;
3387   st->print("Oops:");
3388   if (oops_begin() < oops_end()) {
3389     st->cr();
3390     for (oop* p = oops_begin(); p < oops_end(); p++) {
3391       Disassembler::print_location((unsigned char*)p, (unsigned char*)oops_begin(), (unsigned char*)oops_end(), st, true, false);
3392       st->print(PTR_FORMAT " ", *((uintptr_t*)p));
3393       if (Universe::contains_non_oop_word(p)) {
3394         st->print_cr("NON_OOP");
3395         continue;  // skip non-oops
3396       }
3397       if (*p == nullptr) {
3398         st->print_cr("nullptr-oop");
3399         continue;  // skip non-oops
3400       }
3401       (*p)->print_value_on(st);
3402       st->cr();
3403     }
3404   } else {
3405     st->print_cr(" <list empty>");
3406   }
3407 }
3408 
3409 // Print metadata pool.
3410 void nmethod::print_metadata(outputStream* st) {
3411   ResourceMark m;
3412   st->print("Metadata:");
3413   if (metadata_begin() < metadata_end()) {
3414     st->cr();
3415     for (Metadata** p = metadata_begin(); p < metadata_end(); p++) {
3416       Disassembler::print_location((unsigned char*)p, (unsigned char*)metadata_begin(), (unsigned char*)metadata_end(), st, true, false);
3417       st->print(PTR_FORMAT " ", *((uintptr_t*)p));
3418       if (*p && *p != Universe::non_oop_word()) {
3419         (*p)->print_value_on(st);
3420       }
3421       st->cr();
3422     }
3423   } else {
3424     st->print_cr(" <list empty>");
3425   }
3426 }
3427 
3428 #ifndef PRODUCT  // ScopeDesc::print_on() is available only then. Declared as PRODUCT_RETURN
3429 void nmethod::print_scopes_on(outputStream* st) {
3430   // Find the first pc desc for all scopes in the code and print it.
3431   ResourceMark rm;
3432   st->print("scopes:");
3433   if (scopes_pcs_begin() < scopes_pcs_end()) {
3434     st->cr();
3435     for (PcDesc* p = scopes_pcs_begin(); p < scopes_pcs_end(); p++) {
3436       if (p->scope_decode_offset() == DebugInformationRecorder::serialized_null)
3437         continue;
3438 
3439       ScopeDesc* sd = scope_desc_at(p->real_pc(this));
3440       while (sd != nullptr) {
3441         sd->print_on(st, p);  // print output ends with a newline
3442         sd = sd->sender();
3443       }
3444     }
3445   } else {
3446     st->print_cr(" <list empty>");
3447   }
3448 }
3449 #endif
3450 
3451 #ifndef PRODUCT  // RelocIterator does support printing only then.
3452 void nmethod::print_relocations() {
3453   ResourceMark m;       // in case methods get printed via the debugger
3454   tty->print_cr("relocations:");
3455   RelocIterator iter(this);
3456   iter.print_on(tty);
3457 }
3458 #endif
3459 
3460 void nmethod::print_pcs_on(outputStream* st) {
3461   ResourceMark m;       // in case methods get printed via debugger
3462   st->print("pc-bytecode offsets:");
3463   if (scopes_pcs_begin() < scopes_pcs_end()) {
3464     st->cr();
3465     for (PcDesc* p = scopes_pcs_begin(); p < scopes_pcs_end(); p++) {
3466       p->print_on(st, this);  // print output ends with a newline
3467     }
3468   } else {
3469     st->print_cr(" <list empty>");
3470   }
3471 }
3472 
3473 void nmethod::print_handler_table() {
3474   ExceptionHandlerTable(this).print(code_begin());
3475 }
3476 
3477 void nmethod::print_nul_chk_table() {
3478   ImplicitExceptionTable(this).print(code_begin());
3479 }
3480 
3481 void nmethod::print_recorded_oop(int log_n, int i) {
3482   void* value;
3483 
3484   if (i == 0) {
3485     value = nullptr;
3486   } else {
3487     // Be careful around non-oop words. Don't create an oop
3488     // with that value, or it will assert in verification code.
3489     if (Universe::contains_non_oop_word(oop_addr_at(i))) {
3490       value = Universe::non_oop_word();
3491     } else {
3492       value = oop_at(i);
3493     }
3494   }
3495 
3496   tty->print("#%*d: " INTPTR_FORMAT " ", log_n, i, p2i(value));
3497 
3498   if (value == Universe::non_oop_word()) {
3499     tty->print("non-oop word");
3500   } else {
3501     if (value == nullptr) {
3502       tty->print("nullptr-oop");
3503     } else {
3504       oop_at(i)->print_value_on(tty);
3505     }
3506   }
3507 
3508   tty->cr();
3509 }
3510 
3511 void nmethod::print_recorded_oops() {
3512   const int n = oops_count();
3513   const int log_n = (n<10) ? 1 : (n<100) ? 2 : (n<1000) ? 3 : (n<10000) ? 4 : 6;
3514   tty->print("Recorded oops:");
3515   if (n > 0) {
3516     tty->cr();
3517     for (int i = 0; i < n; i++) {
3518       print_recorded_oop(log_n, i);
3519     }
3520   } else {
3521     tty->print_cr(" <list empty>");
3522   }
3523 }
3524 
3525 void nmethod::print_recorded_metadata() {
3526   const int n = metadata_count();
3527   const int log_n = (n<10) ? 1 : (n<100) ? 2 : (n<1000) ? 3 : (n<10000) ? 4 : 6;
3528   tty->print("Recorded metadata:");
3529   if (n > 0) {
3530     tty->cr();
3531     for (int i = 0; i < n; i++) {
3532       Metadata* m = metadata_at(i);
3533       tty->print("#%*d: " INTPTR_FORMAT " ", log_n, i, p2i(m));
3534       if (m == (Metadata*)Universe::non_oop_word()) {
3535         tty->print("non-metadata word");
3536       } else if (m == nullptr) {
3537         tty->print("nullptr-oop");
3538       } else {
3539         Metadata::print_value_on_maybe_null(tty, m);
3540       }
3541       tty->cr();
3542     }
3543   } else {
3544     tty->print_cr(" <list empty>");
3545   }
3546 }
3547 #endif
3548 
3549 #if defined(SUPPORT_ASSEMBLY) || defined(SUPPORT_ABSTRACT_ASSEMBLY)
3550 
3551 void nmethod::print_constant_pool(outputStream* st) {
3552   //-----------------------------------
3553   //---<  Print the constant pool  >---
3554   //-----------------------------------
3555   int consts_size = this->consts_size();
3556   if ( consts_size > 0 ) {
3557     unsigned char* cstart = this->consts_begin();
3558     unsigned char* cp     = cstart;
3559     unsigned char* cend   = cp + consts_size;
3560     unsigned int   bytes_per_line = 4;
3561     unsigned int   CP_alignment   = 8;
3562     unsigned int   n;
3563 
3564     st->cr();
3565 
3566     //---<  print CP header to make clear what's printed  >---
3567     if( ((uintptr_t)cp&(CP_alignment-1)) == 0 ) {
3568       n = bytes_per_line;
3569       st->print_cr("[Constant Pool]");
3570       Disassembler::print_location(cp, cstart, cend, st, true, true);
3571       Disassembler::print_hexdata(cp, n, st, true);
3572       st->cr();
3573     } else {
3574       n = (int)((uintptr_t)cp & (bytes_per_line-1));
3575       st->print_cr("[Constant Pool (unaligned)]");
3576     }
3577 
3578     //---<  print CP contents, bytes_per_line at a time  >---
3579     while (cp < cend) {
3580       Disassembler::print_location(cp, cstart, cend, st, true, false);
3581       Disassembler::print_hexdata(cp, n, st, false);
3582       cp += n;
3583       n   = bytes_per_line;
3584       st->cr();
3585     }
3586 
3587     //---<  Show potential alignment gap between constant pool and code  >---
3588     cend = code_begin();
3589     if( cp < cend ) {
3590       n = 4;
3591       st->print_cr("[Code entry alignment]");
3592       while (cp < cend) {
3593         Disassembler::print_location(cp, cstart, cend, st, false, false);
3594         cp += n;
3595         st->cr();
3596       }
3597     }
3598   } else {
3599     st->print_cr("[Constant Pool (empty)]");
3600   }
3601   st->cr();
3602 }
3603 
3604 #endif
3605 
3606 // Disassemble this nmethod.
3607 // Print additional debug information, if requested. This could be code
3608 // comments, block comments, profiling counters, etc.
3609 // The undisassembled format is useful no disassembler library is available.
3610 // The resulting hex dump (with markers) can be disassembled later, or on
3611 // another system, when/where a disassembler library is available.
3612 void nmethod::decode2(outputStream* ost) const {
3613 
3614   // Called from frame::back_trace_with_decode without ResourceMark.
3615   ResourceMark rm;
3616 
3617   // Make sure we have a valid stream to print on.
3618   outputStream* st = ost ? ost : tty;
3619 
3620 #if defined(SUPPORT_ABSTRACT_ASSEMBLY) && ! defined(SUPPORT_ASSEMBLY)
3621   const bool use_compressed_format    = true;
3622   const bool compressed_with_comments = use_compressed_format && (AbstractDisassembler::show_comment() ||
3623                                                                   AbstractDisassembler::show_block_comment());
3624 #else
3625   const bool use_compressed_format    = Disassembler::is_abstract();
3626   const bool compressed_with_comments = use_compressed_format && (AbstractDisassembler::show_comment() ||
3627                                                                   AbstractDisassembler::show_block_comment());
3628 #endif
3629 
3630   st->cr();
3631   this->print_on(st);
3632   st->cr();
3633 
3634 #if defined(SUPPORT_ASSEMBLY)
3635   //----------------------------------
3636   //---<  Print real disassembly  >---
3637   //----------------------------------
3638   if (! use_compressed_format) {
3639     st->print_cr("[Disassembly]");
3640     Disassembler::decode(const_cast<nmethod*>(this), st);
3641     st->bol();
3642     st->print_cr("[/Disassembly]");
3643     return;
3644   }
3645 #endif
3646 
3647 #if defined(SUPPORT_ABSTRACT_ASSEMBLY)
3648 
3649   // Compressed undisassembled disassembly format.
3650   // The following status values are defined/supported:
3651   //   = 0 - currently at bol() position, nothing printed yet on current line.
3652   //   = 1 - currently at position after print_location().
3653   //   > 1 - in the midst of printing instruction stream bytes.
3654   int        compressed_format_idx    = 0;
3655   int        code_comment_column      = 0;
3656   const int  instr_maxlen             = Assembler::instr_maxlen();
3657   const uint tabspacing               = 8;
3658   unsigned char* start = this->code_begin();
3659   unsigned char* p     = this->code_begin();
3660   unsigned char* end   = this->code_end();
3661   unsigned char* pss   = p; // start of a code section (used for offsets)
3662 
3663   if ((start == nullptr) || (end == nullptr)) {
3664     st->print_cr("PrintAssembly not possible due to uninitialized section pointers");
3665     return;
3666   }
3667 #endif
3668 
3669 #if defined(SUPPORT_ABSTRACT_ASSEMBLY)
3670   //---<  plain abstract disassembly, no comments or anything, just section headers  >---
3671   if (use_compressed_format && ! compressed_with_comments) {
3672     const_cast<nmethod*>(this)->print_constant_pool(st);
3673 
3674     st->bol();
3675     st->cr();
3676     st->print_cr("Loading hsdis library failed, undisassembled code is shown in MachCode section");
3677     //---<  Open the output (Marker for post-mortem disassembler)  >---
3678     st->print_cr("[MachCode]");
3679     const char* header = nullptr;
3680     address p0 = p;
3681     while (p < end) {
3682       address pp = p;
3683       while ((p < end) && (header == nullptr)) {
3684         header = nmethod_section_label(p);
3685         pp  = p;
3686         p  += Assembler::instr_len(p);
3687       }
3688       if (pp > p0) {
3689         AbstractDisassembler::decode_range_abstract(p0, pp, start, end, st, Assembler::instr_maxlen());
3690         p0 = pp;
3691         p  = pp;
3692         header = nullptr;
3693       } else if (header != nullptr) {
3694         st->bol();
3695         st->print_cr("%s", header);
3696         header = nullptr;
3697       }
3698     }
3699     //---<  Close the output (Marker for post-mortem disassembler)  >---
3700     st->bol();
3701     st->print_cr("[/MachCode]");
3702     return;
3703   }
3704 #endif
3705 
3706 #if defined(SUPPORT_ABSTRACT_ASSEMBLY)
3707   //---<  abstract disassembly with comments and section headers merged in  >---
3708   if (compressed_with_comments) {
3709     const_cast<nmethod*>(this)->print_constant_pool(st);
3710 
3711     st->bol();
3712     st->cr();
3713     st->print_cr("Loading hsdis library failed, undisassembled code is shown in MachCode section");
3714     //---<  Open the output (Marker for post-mortem disassembler)  >---
3715     st->print_cr("[MachCode]");
3716     while ((p < end) && (p != nullptr)) {
3717       const int instruction_size_in_bytes = Assembler::instr_len(p);
3718 
3719       //---<  Block comments for nmethod. Interrupts instruction stream, if any.  >---
3720       // Outputs a bol() before and a cr() after, but only if a comment is printed.
3721       // Prints nmethod_section_label as well.
3722       if (AbstractDisassembler::show_block_comment()) {
3723         print_block_comment(st, p);
3724         if (st->position() == 0) {
3725           compressed_format_idx = 0;
3726         }
3727       }
3728 
3729       //---<  New location information after line break  >---
3730       if (compressed_format_idx == 0) {
3731         code_comment_column   = Disassembler::print_location(p, pss, end, st, false, false);
3732         compressed_format_idx = 1;
3733       }
3734 
3735       //---<  Code comment for current instruction. Address range [p..(p+len))  >---
3736       unsigned char* p_end = p + (ssize_t)instruction_size_in_bytes;
3737       S390_ONLY(if (p_end > end) p_end = end;) // avoid getting past the end
3738 
3739       if (AbstractDisassembler::show_comment() && const_cast<nmethod*>(this)->has_code_comment(p, p_end)) {
3740         //---<  interrupt instruction byte stream for code comment  >---
3741         if (compressed_format_idx > 1) {
3742           st->cr();  // interrupt byte stream
3743           st->cr();  // add an empty line
3744           code_comment_column = Disassembler::print_location(p, pss, end, st, false, false);
3745         }
3746         const_cast<nmethod*>(this)->print_code_comment_on(st, code_comment_column, p, p_end );
3747         st->bol();
3748         compressed_format_idx = 0;
3749       }
3750 
3751       //---<  New location information after line break  >---
3752       if (compressed_format_idx == 0) {
3753         code_comment_column   = Disassembler::print_location(p, pss, end, st, false, false);
3754         compressed_format_idx = 1;
3755       }
3756 
3757       //---<  Nicely align instructions for readability  >---
3758       if (compressed_format_idx > 1) {
3759         Disassembler::print_delimiter(st);
3760       }
3761 
3762       //---<  Now, finally, print the actual instruction bytes  >---
3763       unsigned char* p0 = p;
3764       p = Disassembler::decode_instruction_abstract(p, st, instruction_size_in_bytes, instr_maxlen);
3765       compressed_format_idx += (int)(p - p0);
3766 
3767       if (Disassembler::start_newline(compressed_format_idx-1)) {
3768         st->cr();
3769         compressed_format_idx = 0;
3770       }
3771     }
3772     //---<  Close the output (Marker for post-mortem disassembler)  >---
3773     st->bol();
3774     st->print_cr("[/MachCode]");
3775     return;
3776   }
3777 #endif
3778 }
3779 
3780 #if defined(SUPPORT_ASSEMBLY) || defined(SUPPORT_ABSTRACT_ASSEMBLY)
3781 
3782 const char* nmethod::reloc_string_for(u_char* begin, u_char* end) {
3783   RelocIterator iter(this, begin, end);
3784   bool have_one = false;
3785   while (iter.next()) {
3786     have_one = true;
3787     switch (iter.type()) {
3788         case relocInfo::none: {
3789           // Skip it and check next
3790           break;
3791         }
3792         case relocInfo::oop_type: {
3793           // Get a non-resizable resource-allocated stringStream.
3794           // Our callees make use of (nested) ResourceMarks.
3795           stringStream st(NEW_RESOURCE_ARRAY(char, 1024), 1024);
3796           oop_Relocation* r = iter.oop_reloc();
3797           oop obj = r->oop_value();
3798           st.print("oop(");
3799           if (obj == nullptr) st.print("nullptr");
3800           else obj->print_value_on(&st);
3801           st.print(")");
3802           return st.as_string();
3803         }
3804         case relocInfo::metadata_type: {
3805           stringStream st;
3806           metadata_Relocation* r = iter.metadata_reloc();
3807           Metadata* obj = r->metadata_value();
3808           st.print("metadata(");
3809           if (obj == nullptr) st.print("nullptr");
3810           else obj->print_value_on(&st);
3811           st.print(")");
3812           return st.as_string();
3813         }
3814         case relocInfo::runtime_call_type:
3815         case relocInfo::runtime_call_w_cp_type: {
3816           stringStream st;
3817           st.print("runtime_call");
3818           CallRelocation* r = (CallRelocation*)iter.reloc();
3819           address dest = r->destination();
3820           if (StubRoutines::contains(dest)) {
3821             StubCodeDesc* desc = StubCodeDesc::desc_for(dest);
3822             if (desc != nullptr) {
3823               st.print(" Stub::%s", desc->name());
3824               return st.as_string();
3825             }
3826           }
3827           CodeBlob* cb = CodeCache::find_blob(dest);
3828           if (cb != nullptr) {
3829             st.print(" %s", cb->name());
3830           } else {
3831             ResourceMark rm;
3832             const int buflen = 1024;
3833             char* buf = NEW_RESOURCE_ARRAY(char, buflen);
3834             int offset;
3835             if (os::dll_address_to_function_name(dest, buf, buflen, &offset)) {
3836               st.print(" %s", buf);
3837               if (offset != 0) {
3838                 st.print("+%d", offset);
3839               }
3840             }
3841           }
3842           return st.as_string();
3843         }
3844         case relocInfo::virtual_call_type: {
3845           stringStream st;
3846           st.print_raw("virtual_call");
3847           virtual_call_Relocation* r = iter.virtual_call_reloc();
3848           Method* m = r->method_value();
3849           if (m != nullptr) {
3850             assert(m->is_method(), "");
3851             m->print_short_name(&st);
3852           }
3853           return st.as_string();
3854         }
3855         case relocInfo::opt_virtual_call_type: {
3856           stringStream st;
3857           st.print_raw("optimized virtual_call");
3858           opt_virtual_call_Relocation* r = iter.opt_virtual_call_reloc();
3859           Method* m = r->method_value();
3860           if (m != nullptr) {
3861             assert(m->is_method(), "");
3862             m->print_short_name(&st);
3863           }
3864           return st.as_string();
3865         }
3866         case relocInfo::static_call_type: {
3867           stringStream st;
3868           st.print_raw("static_call");
3869           static_call_Relocation* r = iter.static_call_reloc();
3870           Method* m = r->method_value();
3871           if (m != nullptr) {
3872             assert(m->is_method(), "");
3873             m->print_short_name(&st);
3874           }
3875           return st.as_string();
3876         }
3877         case relocInfo::static_stub_type:      return "static_stub";
3878         case relocInfo::external_word_type:    return "external_word";
3879         case relocInfo::internal_word_type:    return "internal_word";
3880         case relocInfo::section_word_type:     return "section_word";
3881         case relocInfo::poll_type:             return "poll";
3882         case relocInfo::poll_return_type:      return "poll_return";
3883         case relocInfo::trampoline_stub_type:  return "trampoline_stub";
3884         case relocInfo::post_call_nop_type:    return "post_call_nop";
3885         case relocInfo::barrier_type: {
3886           barrier_Relocation* const reloc = iter.barrier_reloc();
3887           stringStream st;
3888           st.print("barrier format=%d", reloc->format());
3889           return st.as_string();
3890         }
3891         case relocInfo::patchable_barrier_type: {
3892           patchable_barrier_Relocation* const reloc = iter.patchable_barrier_reloc();
3893           stringStream st;
3894           st.print("patchable_barrier metadata=0x%x target=" PTR_FORMAT,
3895                    reloc->metadata(), (intptr_t)code_begin() + reloc->target_offset());
3896           return st.as_string();
3897         }
3898 
3899         case relocInfo::type_mask:             return "type_bit_mask";
3900 
3901         default: {
3902           stringStream st;
3903           st.print("unknown relocInfo=%d", (int) iter.type());
3904           return st.as_string();
3905         }
3906     }
3907   }
3908   return have_one ? "other" : nullptr;
3909 }
3910 
3911 // Return the last scope in (begin..end]
3912 ScopeDesc* nmethod::scope_desc_in(address begin, address end) {
3913   PcDesc* p = pc_desc_near(begin+1);
3914   if (p != nullptr && p->real_pc(this) <= end) {
3915     return new ScopeDesc(this, p);
3916   }
3917   return nullptr;
3918 }
3919 
3920 const char* nmethod::nmethod_section_label(address pos) const {
3921   const char* label = nullptr;
3922   if (pos == code_begin())                                              label = "[Instructions begin]";
3923   if (pos == entry_point())                                             label = "[Entry Point]";
3924   if (pos == inline_entry_point())                                      label = "[Inline Entry Point]";
3925   if (pos == verified_entry_point())                                    label = "[Verified Entry Point]";
3926   if (pos == verified_inline_entry_point())                             label = "[Verified Inline Entry Point]";
3927   if (pos == verified_inline_ro_entry_point())                          label = "[Verified Inline Entry Point (RO)]";
3928   if (pos == consts_begin() && pos != insts_begin())                    label = "[Constants]";
3929   // Check stub_code before checking exception_handler or deopt_handler.
3930   if (pos == this->stub_begin())                                        label = "[Stub Code]";
3931   if (pos == exception_begin())                                         label = "[Exception Handler]";
3932   if (pos == deopt_handler_entry())                                     label = "[Deopt Handler Entry Point]";
3933   return label;
3934 }
3935 
3936 static int maybe_print_entry_label(outputStream* stream, address pos, address entry, const char* label) {
3937   if (pos == entry) {
3938     stream->bol();
3939     stream->print_cr("%s", label);
3940     return 1;
3941   } else {
3942     return 0;
3943   }
3944 }
3945 
3946 void nmethod::print_nmethod_labels(outputStream* stream, address block_begin, bool print_section_labels) const {
3947   if (print_section_labels) {
3948     int n = 0;
3949     // Multiple entry points may be at the same position. Print them all.
3950     n += maybe_print_entry_label(stream, block_begin, entry_point(),                    "[Entry Point]");
3951     n += maybe_print_entry_label(stream, block_begin, inline_entry_point(),             "[Inline Entry Point]");
3952     n += maybe_print_entry_label(stream, block_begin, verified_entry_point(),           "[Verified Entry Point]");
3953     n += maybe_print_entry_label(stream, block_begin, verified_inline_entry_point(),    "[Verified Inline Entry Point]");
3954     n += maybe_print_entry_label(stream, block_begin, verified_inline_ro_entry_point(), "[Verified Inline Entry Point (RO)]");
3955     if (n == 0) {
3956       const char* label = nmethod_section_label(block_begin);
3957       if (label != nullptr) {
3958         stream->bol();
3959         stream->print_cr("%s", label);
3960       }
3961     }
3962   }
3963 
3964   Method* m = method();
3965   if (m == nullptr || is_osr_method()) {
3966     return;
3967   }
3968 
3969   // Print the name of the method (only once)
3970   address low = MIN3(entry_point(),
3971                      verified_entry_point(),
3972                      inline_entry_point());
3973   // The verified inline entry point and verified inline RO entry point are not always
3974   // used. When they are unused. CodeOffsets::Verified_Inline_Entry(_RO) is -1. Hence,
3975   // the calculated entry point is smaller than the block they are offsetting into.
3976   if (verified_inline_entry_point() >= block_begin) {
3977     low = MIN2(low, verified_inline_entry_point());
3978   }
3979   if (verified_inline_ro_entry_point() >= block_begin) {
3980     low = MIN2(low, verified_inline_ro_entry_point());
3981   }
3982   assert(low != nullptr, "sanity");
3983   if (block_begin == low) {
3984     stream->print("  # ");
3985     m->print_value_on(stream);
3986     stream->cr();
3987   }
3988 
3989   // Print the arguments for the 3 types of verified entry points
3990   CompiledEntrySignature ces(m);
3991   ces.compute_calling_conventions(false);
3992   const GrowableArray<SigEntry>* sig_cc;
3993   const VMRegPair* regs;
3994   if (block_begin == verified_entry_point()) {
3995     sig_cc = ces.sig_cc();
3996     regs = ces.regs_cc();
3997   } else if (block_begin == verified_inline_entry_point()) {
3998     sig_cc = ces.sig();
3999     regs = ces.regs();
4000   } else if (block_begin == verified_inline_ro_entry_point()) {
4001     sig_cc = ces.sig_cc_ro();
4002     regs = ces.regs_cc_ro();
4003   } else {
4004     return;
4005   }
4006 
4007   bool has_this = !m->is_static();
4008   if (ces.has_inline_recv() && block_begin == verified_entry_point()) {
4009     // <this> argument is scalarized for verified_entry_point()
4010     has_this = false;
4011   }
4012   const char* spname = "sp"; // make arch-specific?
4013   int stack_slot_offset = this->frame_size() * wordSize;
4014   int tab1 = 14, tab2 = 24;
4015   int sig_index = 0;
4016   int arg_index = has_this ? -1 : 0;
4017   bool did_old_sp = false;
4018   for (ExtendedSignature sig = ExtendedSignature(sig_cc, SigEntryFilter()); !sig.at_end(); ++sig) {
4019     bool at_this = (arg_index == -1);
4020     bool at_old_sp = false;
4021     BasicType t = (*sig)._bt;
4022     if (at_this) {
4023       stream->print("  # this: ");
4024     } else {
4025       stream->print("  # parm%d: ", arg_index);
4026     }
4027     stream->move_to(tab1);
4028     VMReg fst = regs[sig_index].first();
4029     VMReg snd = regs[sig_index].second();
4030     if (fst->is_reg()) {
4031       stream->print("%s", fst->name());
4032       if (snd->is_valid())  {
4033         stream->print(":%s", snd->name());
4034       }
4035     } else if (fst->is_stack()) {
4036       int offset = fst->reg2stack() * VMRegImpl::stack_slot_size + stack_slot_offset;
4037       if (offset == stack_slot_offset)  at_old_sp = true;
4038       stream->print("[%s+0x%x]", spname, offset);
4039     } else {
4040       stream->print("reg%d:%d??", (int)(intptr_t)fst, (int)(intptr_t)snd);
4041     }
4042     stream->print(" ");
4043     stream->move_to(tab2);
4044     stream->print("= ");
4045     if (at_this) {
4046       m->method_holder()->print_value_on(stream);
4047     } else {
4048       bool did_name = false;
4049       if (is_reference_type(t) && !(*sig)._vt_oop) {
4050         Symbol* name = (*sig)._name;
4051         name->print_value_on(stream);
4052         did_name = true;
4053       }
4054       if (!did_name)
4055         stream->print("%s", type2name(t));
4056       if ((*sig)._null_marker) {
4057         stream->print(" (null marker)");
4058       }
4059       if ((*sig)._vt_oop) {
4060         stream->print(" (VT OOP)");
4061       }
4062     }
4063     if (at_old_sp) {
4064       stream->print("  (%s of caller)", spname);
4065       did_old_sp = true;
4066     }
4067     stream->cr();
4068     sig_index += type2size[t];
4069     arg_index += 1;
4070   }
4071   if (!did_old_sp) {
4072     stream->print("  # ");
4073     stream->move_to(tab1);
4074     stream->print("[%s+0x%x]", spname, stack_slot_offset);
4075     stream->print("  (%s of caller)", spname);
4076     stream->cr();
4077   }
4078 }
4079 
4080 // Returns whether this nmethod has code comments.
4081 bool nmethod::has_code_comment(address begin, address end) {
4082   // scopes?
4083   ScopeDesc* sd  = scope_desc_in(begin, end);
4084   if (sd != nullptr) return true;
4085 
4086   // relocations?
4087   const char* str = reloc_string_for(begin, end);
4088   if (str != nullptr) return true;
4089 
4090   // implicit exceptions?
4091   int cont_offset = ImplicitExceptionTable(this).continuation_offset((uint)(begin - code_begin()));
4092   if (cont_offset != 0) return true;
4093 
4094   return false;
4095 }
4096 
4097 void nmethod::print_code_comment_on(outputStream* st, int column, address begin, address end) {
4098   ImplicitExceptionTable implicit_table(this);
4099   int pc_offset = (int)(begin - code_begin());
4100   int cont_offset = implicit_table.continuation_offset(pc_offset);
4101   bool oop_map_required = false;
4102   if (cont_offset != 0) {
4103     st->move_to(column, 6, 0);
4104     if (pc_offset == cont_offset) {
4105       st->print("; implicit exception: deoptimizes");
4106       oop_map_required = true;
4107     } else {
4108       st->print("; implicit exception: dispatches to " INTPTR_FORMAT, p2i(code_begin() + cont_offset));
4109     }
4110   }
4111 
4112   // Find an oopmap in (begin, end].  We use the odd half-closed
4113   // interval so that oop maps and scope descs which are tied to the
4114   // byte after a call are printed with the call itself.  OopMaps
4115   // associated with implicit exceptions are printed with the implicit
4116   // instruction.
4117   address base = code_begin();
4118   ImmutableOopMapSet* oms = oop_maps();
4119   if (oms != nullptr) {
4120     for (int i = 0, imax = oms->count(); i < imax; i++) {
4121       const ImmutableOopMapPair* pair = oms->pair_at(i);
4122       const ImmutableOopMap* om = pair->get_from(oms);
4123       address pc = base + pair->pc_offset();
4124       if (pc >= begin) {
4125         if (pc > begin && pc <= end) {
4126           st->move_to(column, 6, 0);
4127           st->print("; ");
4128           om->print_on(st);
4129           oop_map_required = false;
4130         }
4131       }
4132       if (pc > end) {
4133         break;
4134       }
4135     }
4136   }
4137   assert(!oop_map_required, "missed oopmap");
4138 
4139   Thread* thread = Thread::current();
4140 
4141   // Print any debug info present at this pc.
4142   ScopeDesc* sd  = scope_desc_in(begin, end);
4143   if (sd != nullptr) {
4144     st->move_to(column, 6, 0);
4145     if (sd->bci() == SynchronizationEntryBCI) {
4146       st->print(";*synchronization entry");
4147     } else if (sd->bci() == AfterBci) {
4148       st->print(";* method exit (unlocked if synchronized)");
4149     } else if (sd->bci() == UnwindBci) {
4150       st->print(";* unwind (locked if synchronized)");
4151     } else if (sd->bci() == AfterExceptionBci) {
4152       st->print(";* unwind (unlocked if synchronized)");
4153     } else if (sd->bci() == UnknownBci) {
4154       st->print(";* unknown");
4155     } else if (sd->bci() == InvalidFrameStateBci) {
4156       st->print(";* invalid frame state");
4157     } else {
4158       if (sd->method() == nullptr) {
4159         st->print("method is nullptr");
4160       } else if (sd->method()->is_native()) {
4161         st->print("method is native");
4162       } else {
4163         Bytecodes::Code bc = sd->method()->java_code_at(sd->bci());
4164         st->print(";*%s", Bytecodes::name(bc));
4165         switch (bc) {
4166         case Bytecodes::_invokevirtual:
4167         case Bytecodes::_invokespecial:
4168         case Bytecodes::_invokestatic:
4169         case Bytecodes::_invokeinterface:
4170           {
4171             Bytecode_invoke invoke(methodHandle(thread, sd->method()), sd->bci());
4172             st->print(" ");
4173             if (invoke.name() != nullptr)
4174               invoke.name()->print_symbol_on(st);
4175             else
4176               st->print("<UNKNOWN>");
4177             break;
4178           }
4179         case Bytecodes::_getfield:
4180         case Bytecodes::_putfield:
4181         case Bytecodes::_getstatic:
4182         case Bytecodes::_putstatic:
4183           {
4184             Bytecode_field field(methodHandle(thread, sd->method()), sd->bci());
4185             st->print(" ");
4186             if (field.name() != nullptr)
4187               field.name()->print_symbol_on(st);
4188             else
4189               st->print("<UNKNOWN>");
4190           }
4191         default:
4192           break;
4193         }
4194       }
4195       st->print(" {reexecute=%d rethrow=%d return_oop=%d return_scalarized=%d}", sd->should_reexecute(), sd->rethrow_exception(), sd->return_oop(), sd->return_scalarized());
4196     }
4197 
4198     // Print all scopes
4199     for (;sd != nullptr; sd = sd->sender()) {
4200       st->move_to(column, 6, 0);
4201       st->print("; -");
4202       if (sd->should_reexecute()) {
4203         st->print(" (reexecute)");
4204       }
4205       if (sd->method() == nullptr) {
4206         st->print("method is nullptr");
4207       } else {
4208         sd->method()->print_short_name(st);
4209       }
4210       int lineno = sd->method()->line_number_from_bci(sd->bci());
4211       if (lineno != -1) {
4212         st->print("@%d (line %d)", sd->bci(), lineno);
4213       } else {
4214         st->print("@%d", sd->bci());
4215       }
4216       st->cr();
4217     }
4218   }
4219 
4220   // Print relocation information
4221   // Prevent memory leak: allocating without ResourceMark.
4222   ResourceMark rm;
4223   const char* str = reloc_string_for(begin, end);
4224   if (str != nullptr) {
4225     if (sd != nullptr) st->cr();
4226     st->move_to(column, 6, 0);
4227     st->print(";   {%s}", str);
4228   }
4229 }
4230 
4231 #endif
4232 
4233 address nmethod::call_instruction_address(address pc) const {
4234   if (NativeCall::is_call_before(pc)) {
4235     NativeCall *ncall = nativeCall_before(pc);
4236     return ncall->instruction_address();
4237   }
4238   return nullptr;
4239 }
4240 
4241 void nmethod::print_value_on_impl(outputStream* st) const {
4242   st->print_cr("nmethod");
4243 #if defined(SUPPORT_DATA_STRUCTS)
4244   print_on_with_msg(st, nullptr);
4245 #endif
4246 }
4247 
4248 void nmethod::print_code_snippet(outputStream* st, address addr) const {
4249   if (entry_point() <= addr && addr < code_end()) {
4250     // Pointing into the nmethod's code. Try to disassemble some instructions around addr.
4251     // Determine conservative start and end points.
4252     address start;
4253     if (frame_complete_offset() != CodeOffsets::frame_never_safe &&
4254         addr >= code_begin() + frame_complete_offset()) {
4255       start = code_begin() + frame_complete_offset();
4256     } else {
4257       start = (addr < verified_entry_point()) ? entry_point() : verified_entry_point();
4258     }
4259     address start_for_hex_dump = start; // We can choose a different starting point for hex dump, below.
4260     address end = code_end();
4261 
4262     // Try using relocations to find closer instruction start and end points.
4263     // (Some platforms have variable length instructions and can only
4264     // disassemble correctly at instruction start addresses.)
4265     RelocIterator iter((nmethod*)this, start);
4266     while (iter.next() && iter.addr() < addr) { // find relocation before addr
4267       // Note: There's a relocation which doesn't point to an instruction start:
4268       // ZBarrierRelocationFormatStoreGoodAfterMov with ZGC on x86_64
4269       // We could detect and skip it, but hex dump is still usable when
4270       // disassembler produces garbage in such a very rare case.
4271       start = iter.addr();
4272       // We want at least 64 Bytes ahead in hex dump.
4273       if (iter.addr() <= (addr - 64)) start_for_hex_dump = iter.addr();
4274     }
4275     if (iter.has_current()) {
4276       if (iter.addr() == addr) iter.next(); // find relocation after addr
4277       if (iter.has_current()) end = iter.addr();
4278     }
4279 
4280     // Always print hex. Disassembler may still have problems when hitting an incorrect instruction start.
4281     os::print_hex_dump(st, start_for_hex_dump, end, 1, /* print_ascii=*/false);
4282     if (!Disassembler::is_abstract()) {
4283       Disassembler::decode(start, end, st);
4284     }
4285   }
4286 }
4287 
4288 #ifndef PRODUCT
4289 
4290 void nmethod::print_calls(outputStream* st) {
4291   RelocIterator iter(this);
4292   while (iter.next()) {
4293     switch (iter.type()) {
4294     case relocInfo::virtual_call_type: {
4295       CompiledICLocker ml_verify(this);
4296       CompiledIC_at(&iter)->print();
4297       break;
4298     }
4299     case relocInfo::static_call_type:
4300     case relocInfo::opt_virtual_call_type:
4301       st->print_cr("Direct call at " INTPTR_FORMAT, p2i(iter.reloc()->addr()));
4302       CompiledDirectCall::at(iter.reloc())->print();
4303       break;
4304     default:
4305       break;
4306     }
4307   }
4308 }
4309 
4310 void nmethod::print_statistics() {
4311   ttyLocker ttyl;
4312   if (xtty != nullptr)  xtty->head("statistics type='nmethod'");
4313   native_nmethod_stats.print_native_nmethod_stats();
4314 #ifdef COMPILER1
4315   c1_java_nmethod_stats.print_nmethod_stats("C1");
4316 #endif
4317 #ifdef COMPILER2
4318   c2_java_nmethod_stats.print_nmethod_stats("C2");
4319 #endif
4320   unknown_java_nmethod_stats.print_nmethod_stats("Unknown");
4321   DebugInformationRecorder::print_statistics();
4322   pc_nmethod_stats.print_pc_stats();
4323   Dependencies::print_statistics();
4324   ExternalsRecorder::print_statistics();
4325   if (xtty != nullptr)  xtty->tail("statistics");
4326 }
4327 
4328 #endif // !PRODUCT