1 /*
   2  * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "code/codeCache.hpp"
  27 #include "code/compiledIC.hpp"
  28 #include "code/dependencies.hpp"
  29 #include "code/nmethod.hpp"
  30 #include "code/scopeDesc.hpp"
  31 #include "compiler/abstractCompiler.hpp"
  32 #include "compiler/compileBroker.hpp"
  33 #include "compiler/compileLog.hpp"
  34 #include "compiler/compilerOracle.hpp"
  35 #include "compiler/disassembler.hpp"
  36 #include "interpreter/bytecode.hpp"
  37 #include "oops/methodData.hpp"
  38 #include "prims/jvmtiRedefineClassesTrace.hpp"
  39 #include "prims/jvmtiImpl.hpp"
  40 #include "runtime/atomic.inline.hpp"
  41 #include "runtime/orderAccess.inline.hpp"
  42 #include "runtime/sharedRuntime.hpp"
  43 #include "runtime/sweeper.hpp"
  44 #include "utilities/resourceHash.hpp"
  45 #include "utilities/dtrace.hpp"
  46 #include "utilities/events.hpp"
  47 #include "utilities/xmlstream.hpp"
  48 #ifdef SHARK
  49 #include "shark/sharkCompiler.hpp"
  50 #endif
  51 
  52 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
  53 
  54 unsigned char nmethod::_global_unloading_clock = 0;
  55 
  56 #ifdef DTRACE_ENABLED
  57 
  58 // Only bother with this argument setup if dtrace is available
  59 
  60 #define DTRACE_METHOD_UNLOAD_PROBE(method)                                \
  61   {                                                                       \
  62     Method* m = (method);                                                 \
  63     if (m != NULL) {                                                      \
  64       Symbol* klass_name = m->klass_name();                               \
  65       Symbol* name = m->name();                                           \
  66       Symbol* signature = m->signature();                                 \
  67       HOTSPOT_COMPILED_METHOD_UNLOAD(                                     \
  68         (char *) klass_name->bytes(), klass_name->utf8_length(),                   \
  69         (char *) name->bytes(), name->utf8_length(),                               \
  70         (char *) signature->bytes(), signature->utf8_length());                    \
  71     }                                                                     \
  72   }
  73 
  74 #else //  ndef DTRACE_ENABLED
  75 
  76 #define DTRACE_METHOD_UNLOAD_PROBE(method)
  77 
  78 #endif
  79 
  80 bool nmethod::is_compiled_by_c1() const {
  81   if (compiler() == NULL) {
  82     return false;
  83   }
  84   return compiler()->is_c1();
  85 }
  86 bool nmethod::is_compiled_by_c2() const {
  87   if (compiler() == NULL) {
  88     return false;
  89   }
  90   return compiler()->is_c2();
  91 }
  92 bool nmethod::is_compiled_by_shark() const {
  93   if (compiler() == NULL) {
  94     return false;
  95   }
  96   return compiler()->is_shark();
  97 }
  98 
  99 
 100 
 101 //---------------------------------------------------------------------------------
 102 // NMethod statistics
 103 // They are printed under various flags, including:
 104 //   PrintC1Statistics, PrintOptoStatistics, LogVMOutput, and LogCompilation.
 105 // (In the latter two cases, they like other stats are printed to the log only.)
 106 
 107 #ifndef PRODUCT
 108 // These variables are put into one block to reduce relocations
 109 // and make it simpler to print from the debugger.
 110 static
 111 struct nmethod_stats_struct {
 112   int nmethod_count;
 113   int total_size;
 114   int relocation_size;
 115   int consts_size;
 116   int insts_size;
 117   int stub_size;
 118   int scopes_data_size;
 119   int scopes_pcs_size;
 120   int dependencies_size;
 121   int handler_table_size;
 122   int nul_chk_table_size;
 123   int oops_size;
 124 
 125   void note_nmethod(nmethod* nm) {
 126     nmethod_count += 1;
 127     total_size          += nm->size();
 128     relocation_size     += nm->relocation_size();
 129     consts_size         += nm->consts_size();
 130     insts_size          += nm->insts_size();
 131     stub_size           += nm->stub_size();
 132     oops_size           += nm->oops_size();
 133     scopes_data_size    += nm->scopes_data_size();
 134     scopes_pcs_size     += nm->scopes_pcs_size();
 135     dependencies_size   += nm->dependencies_size();
 136     handler_table_size  += nm->handler_table_size();
 137     nul_chk_table_size  += nm->nul_chk_table_size();
 138   }
 139   void print_nmethod_stats() {
 140     if (nmethod_count == 0)  return;
 141     tty->print_cr("Statistics for %d bytecoded nmethods:", nmethod_count);
 142     if (total_size != 0)          tty->print_cr(" total in heap  = %d", total_size);
 143     if (relocation_size != 0)     tty->print_cr(" relocation     = %d", relocation_size);
 144     if (consts_size != 0)         tty->print_cr(" constants      = %d", consts_size);
 145     if (insts_size != 0)          tty->print_cr(" main code      = %d", insts_size);
 146     if (stub_size != 0)           tty->print_cr(" stub code      = %d", stub_size);
 147     if (oops_size != 0)           tty->print_cr(" oops           = %d", oops_size);
 148     if (scopes_data_size != 0)    tty->print_cr(" scopes data    = %d", scopes_data_size);
 149     if (scopes_pcs_size != 0)     tty->print_cr(" scopes pcs     = %d", scopes_pcs_size);
 150     if (dependencies_size != 0)   tty->print_cr(" dependencies   = %d", dependencies_size);
 151     if (handler_table_size != 0)  tty->print_cr(" handler table  = %d", handler_table_size);
 152     if (nul_chk_table_size != 0)  tty->print_cr(" nul chk table  = %d", nul_chk_table_size);
 153   }
 154 
 155   int native_nmethod_count;
 156   int native_total_size;
 157   int native_relocation_size;
 158   int native_insts_size;
 159   int native_oops_size;
 160   void note_native_nmethod(nmethod* nm) {
 161     native_nmethod_count += 1;
 162     native_total_size       += nm->size();
 163     native_relocation_size  += nm->relocation_size();
 164     native_insts_size       += nm->insts_size();
 165     native_oops_size        += nm->oops_size();
 166   }
 167   void print_native_nmethod_stats() {
 168     if (native_nmethod_count == 0)  return;
 169     tty->print_cr("Statistics for %d native nmethods:", native_nmethod_count);
 170     if (native_total_size != 0)       tty->print_cr(" N. total size  = %d", native_total_size);
 171     if (native_relocation_size != 0)  tty->print_cr(" N. relocation  = %d", native_relocation_size);
 172     if (native_insts_size != 0)       tty->print_cr(" N. main code   = %d", native_insts_size);
 173     if (native_oops_size != 0)        tty->print_cr(" N. oops        = %d", native_oops_size);
 174   }
 175 
 176   int pc_desc_resets;   // number of resets (= number of caches)
 177   int pc_desc_queries;  // queries to nmethod::find_pc_desc
 178   int pc_desc_approx;   // number of those which have approximate true
 179   int pc_desc_repeats;  // number of _pc_descs[0] hits
 180   int pc_desc_hits;     // number of LRU cache hits
 181   int pc_desc_tests;    // total number of PcDesc examinations
 182   int pc_desc_searches; // total number of quasi-binary search steps
 183   int pc_desc_adds;     // number of LUR cache insertions
 184 
 185   void print_pc_stats() {
 186     tty->print_cr("PcDesc Statistics:  %d queries, %.2f comparisons per query",
 187                   pc_desc_queries,
 188                   (double)(pc_desc_tests + pc_desc_searches)
 189                   / pc_desc_queries);
 190     tty->print_cr("  caches=%d queries=%d/%d, hits=%d+%d, tests=%d+%d, adds=%d",
 191                   pc_desc_resets,
 192                   pc_desc_queries, pc_desc_approx,
 193                   pc_desc_repeats, pc_desc_hits,
 194                   pc_desc_tests, pc_desc_searches, pc_desc_adds);
 195   }
 196 } nmethod_stats;
 197 #endif //PRODUCT
 198 
 199 
 200 //---------------------------------------------------------------------------------
 201 
 202 
 203 ExceptionCache::ExceptionCache(Handle exception, address pc, address handler) {
 204   assert(pc != NULL, "Must be non null");
 205   assert(exception.not_null(), "Must be non null");
 206   assert(handler != NULL, "Must be non null");
 207 
 208   _count = 0;
 209   _exception_type = exception->klass();
 210   _next = NULL;
 211 
 212   add_address_and_handler(pc,handler);
 213 }
 214 
 215 
 216 address ExceptionCache::match(Handle exception, address pc) {
 217   assert(pc != NULL,"Must be non null");
 218   assert(exception.not_null(),"Must be non null");
 219   if (exception->klass() == exception_type()) {
 220     return (test_address(pc));
 221   }
 222 
 223   return NULL;
 224 }
 225 
 226 
 227 bool ExceptionCache::match_exception_with_space(Handle exception) {
 228   assert(exception.not_null(),"Must be non null");
 229   if (exception->klass() == exception_type() && count() < cache_size) {
 230     return true;
 231   }
 232   return false;
 233 }
 234 
 235 
 236 address ExceptionCache::test_address(address addr) {
 237   for (int i=0; i<count(); i++) {
 238     if (pc_at(i) == addr) {
 239       return handler_at(i);
 240     }
 241   }
 242   return NULL;
 243 }
 244 
 245 
 246 bool ExceptionCache::add_address_and_handler(address addr, address handler) {
 247   if (test_address(addr) == handler) return true;
 248   if (count() < cache_size) {
 249     set_pc_at(count(),addr);
 250     set_handler_at(count(), handler);
 251     increment_count();
 252     return true;
 253   }
 254   return false;
 255 }
 256 
 257 
 258 // private method for handling exception cache
 259 // These methods are private, and used to manipulate the exception cache
 260 // directly.
 261 ExceptionCache* nmethod::exception_cache_entry_for_exception(Handle exception) {
 262   ExceptionCache* ec = exception_cache();
 263   while (ec != NULL) {
 264     if (ec->match_exception_with_space(exception)) {
 265       return ec;
 266     }
 267     ec = ec->next();
 268   }
 269   return NULL;
 270 }
 271 
 272 
 273 //-----------------------------------------------------------------------------
 274 
 275 
 276 // Helper used by both find_pc_desc methods.
 277 static inline bool match_desc(PcDesc* pc, int pc_offset, bool approximate) {
 278   NOT_PRODUCT(++nmethod_stats.pc_desc_tests);
 279   if (!approximate)
 280     return pc->pc_offset() == pc_offset;
 281   else
 282     return (pc-1)->pc_offset() < pc_offset && pc_offset <= pc->pc_offset();
 283 }
 284 
 285 void PcDescCache::reset_to(PcDesc* initial_pc_desc) {
 286   if (initial_pc_desc == NULL) {
 287     _pc_descs[0] = NULL; // native method; no PcDescs at all
 288     return;
 289   }
 290   NOT_PRODUCT(++nmethod_stats.pc_desc_resets);
 291   // reset the cache by filling it with benign (non-null) values
 292   assert(initial_pc_desc->pc_offset() < 0, "must be sentinel");
 293   for (int i = 0; i < cache_size; i++)
 294     _pc_descs[i] = initial_pc_desc;
 295 }
 296 
 297 PcDesc* PcDescCache::find_pc_desc(int pc_offset, bool approximate) {
 298   NOT_PRODUCT(++nmethod_stats.pc_desc_queries);
 299   NOT_PRODUCT(if (approximate) ++nmethod_stats.pc_desc_approx);
 300 
 301   // Note: one might think that caching the most recently
 302   // read value separately would be a win, but one would be
 303   // wrong.  When many threads are updating it, the cache
 304   // line it's in would bounce between caches, negating
 305   // any benefit.
 306 
 307   // In order to prevent race conditions do not load cache elements
 308   // repeatedly, but use a local copy:
 309   PcDesc* res;
 310 
 311   // Step one:  Check the most recently added value.
 312   res = _pc_descs[0];
 313   if (res == NULL) return NULL;  // native method; no PcDescs at all
 314   if (match_desc(res, pc_offset, approximate)) {
 315     NOT_PRODUCT(++nmethod_stats.pc_desc_repeats);
 316     return res;
 317   }
 318 
 319   // Step two:  Check the rest of the LRU cache.
 320   for (int i = 1; i < cache_size; ++i) {
 321     res = _pc_descs[i];
 322     if (res->pc_offset() < 0) break;  // optimization: skip empty cache
 323     if (match_desc(res, pc_offset, approximate)) {
 324       NOT_PRODUCT(++nmethod_stats.pc_desc_hits);
 325       return res;
 326     }
 327   }
 328 
 329   // Report failure.
 330   return NULL;
 331 }
 332 
 333 void PcDescCache::add_pc_desc(PcDesc* pc_desc) {
 334   NOT_PRODUCT(++nmethod_stats.pc_desc_adds);
 335   // Update the LRU cache by shifting pc_desc forward.
 336   for (int i = 0; i < cache_size; i++)  {
 337     PcDesc* next = _pc_descs[i];
 338     _pc_descs[i] = pc_desc;
 339     pc_desc = next;
 340   }
 341 }
 342 
 343 // adjust pcs_size so that it is a multiple of both oopSize and
 344 // sizeof(PcDesc) (assumes that if sizeof(PcDesc) is not a multiple
 345 // of oopSize, then 2*sizeof(PcDesc) is)
 346 static int adjust_pcs_size(int pcs_size) {
 347   int nsize = round_to(pcs_size,   oopSize);
 348   if ((nsize % sizeof(PcDesc)) != 0) {
 349     nsize = pcs_size + sizeof(PcDesc);
 350   }
 351   assert((nsize % oopSize) == 0, "correct alignment");
 352   return nsize;
 353 }
 354 
 355 //-----------------------------------------------------------------------------
 356 
 357 
 358 void nmethod::add_exception_cache_entry(ExceptionCache* new_entry) {
 359   assert(ExceptionCache_lock->owned_by_self(),"Must hold the ExceptionCache_lock");
 360   assert(new_entry != NULL,"Must be non null");
 361   assert(new_entry->next() == NULL, "Must be null");
 362 
 363   if (exception_cache() != NULL) {
 364     new_entry->set_next(exception_cache());
 365   }
 366   set_exception_cache(new_entry);
 367 }
 368 
 369 void nmethod::clean_exception_cache(BoolObjectClosure* is_alive) {
 370   ExceptionCache* prev = NULL;
 371   ExceptionCache* curr = exception_cache();
 372 
 373   while (curr != NULL) {
 374     ExceptionCache* next = curr->next();
 375 
 376     Klass* ex_klass = curr->exception_type();
 377     if (ex_klass != NULL && !ex_klass->is_loader_alive(is_alive)) {
 378       if (prev == NULL) {
 379         set_exception_cache(next);
 380       } else {
 381         prev->set_next(next);
 382       }
 383       delete curr;
 384       // prev stays the same.
 385     } else {
 386       prev = curr;
 387     }
 388 
 389     curr = next;
 390   }
 391 }
 392 
 393 // public method for accessing the exception cache
 394 // These are the public access methods.
 395 address nmethod::handler_for_exception_and_pc(Handle exception, address pc) {
 396   // We never grab a lock to read the exception cache, so we may
 397   // have false negatives. This is okay, as it can only happen during
 398   // the first few exception lookups for a given nmethod.
 399   ExceptionCache* ec = exception_cache();
 400   while (ec != NULL) {
 401     address ret_val;
 402     if ((ret_val = ec->match(exception,pc)) != NULL) {
 403       return ret_val;
 404     }
 405     ec = ec->next();
 406   }
 407   return NULL;
 408 }
 409 
 410 
 411 void nmethod::add_handler_for_exception_and_pc(Handle exception, address pc, address handler) {
 412   // There are potential race conditions during exception cache updates, so we
 413   // must own the ExceptionCache_lock before doing ANY modifications. Because
 414   // we don't lock during reads, it is possible to have several threads attempt
 415   // to update the cache with the same data. We need to check for already inserted
 416   // copies of the current data before adding it.
 417 
 418   MutexLocker ml(ExceptionCache_lock);
 419   ExceptionCache* target_entry = exception_cache_entry_for_exception(exception);
 420 
 421   if (target_entry == NULL || !target_entry->add_address_and_handler(pc,handler)) {
 422     target_entry = new ExceptionCache(exception,pc,handler);
 423     add_exception_cache_entry(target_entry);
 424   }
 425 }
 426 
 427 
 428 //-------------end of code for ExceptionCache--------------
 429 
 430 
 431 int nmethod::total_size() const {
 432   return
 433     consts_size()        +
 434     insts_size()         +
 435     stub_size()          +
 436     scopes_data_size()   +
 437     scopes_pcs_size()    +
 438     handler_table_size() +
 439     nul_chk_table_size();
 440 }
 441 
 442 const char* nmethod::compile_kind() const {
 443   if (is_osr_method())     return "osr";
 444   if (method() != NULL && is_native_method())  return "c2n";
 445   return NULL;
 446 }
 447 
 448 // Fill in default values for various flag fields
 449 void nmethod::init_defaults() {
 450   _state                      = in_use;
 451   _unloading_clock            = 0;
 452   _marked_for_reclamation     = 0;
 453   _has_flushed_dependencies   = 0;
 454   _has_unsafe_access          = 0;
 455   _has_method_handle_invokes  = 0;
 456   _lazy_critical_native       = 0;
 457   _has_wide_vectors           = 0;
 458   _marked_for_deoptimization  = 0;
 459   _lock_count                 = 0;
 460   _stack_traversal_mark       = 0;
 461   _unload_reported            = false;           // jvmti state
 462 
 463 #ifdef ASSERT
 464   _oops_are_stale             = false;
 465 #endif
 466 
 467   _oops_do_mark_link       = NULL;
 468   _jmethod_id              = NULL;
 469   _osr_link                = NULL;
 470   if (UseG1GC) {
 471     _unloading_next        = NULL;
 472   } else {
 473     _scavenge_root_link    = NULL;
 474   }
 475   _scavenge_root_state     = 0;
 476   _compiler                = NULL;
 477 #if INCLUDE_RTM_OPT
 478   _rtm_state               = NoRTM;
 479 #endif
 480 #ifdef HAVE_DTRACE_H
 481   _trap_offset             = 0;
 482 #endif // def HAVE_DTRACE_H
 483 }
 484 
 485 nmethod* nmethod::new_native_nmethod(methodHandle method,
 486   int compile_id,
 487   CodeBuffer *code_buffer,
 488   int vep_offset,
 489   int frame_complete,
 490   int frame_size,
 491   ByteSize basic_lock_owner_sp_offset,
 492   ByteSize basic_lock_sp_offset,
 493   OopMapSet* oop_maps) {
 494   code_buffer->finalize_oop_references(method);
 495   // create nmethod
 496   nmethod* nm = NULL;
 497   {
 498     MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
 499     int native_nmethod_size = allocation_size(code_buffer, sizeof(nmethod));
 500     CodeOffsets offsets;
 501     offsets.set_value(CodeOffsets::Verified_Entry, vep_offset);
 502     offsets.set_value(CodeOffsets::Frame_Complete, frame_complete);
 503     nm = new (native_nmethod_size) nmethod(method(), native_nmethod_size,
 504                                             compile_id, &offsets,
 505                                             code_buffer, frame_size,
 506                                             basic_lock_owner_sp_offset,
 507                                             basic_lock_sp_offset, oop_maps);
 508     NOT_PRODUCT(if (nm != NULL)  nmethod_stats.note_native_nmethod(nm));
 509     if (PrintAssembly && nm != NULL) {
 510       Disassembler::decode(nm);
 511     }
 512   }
 513   // verify nmethod
 514   debug_only(if (nm) nm->verify();) // might block
 515 
 516   if (nm != NULL) {
 517     nm->log_new_nmethod();
 518   }
 519 
 520   return nm;
 521 }
 522 
 523 #ifdef HAVE_DTRACE_H
 524 nmethod* nmethod::new_dtrace_nmethod(methodHandle method,
 525                                      CodeBuffer *code_buffer,
 526                                      int vep_offset,
 527                                      int trap_offset,
 528                                      int frame_complete,
 529                                      int frame_size) {
 530   code_buffer->finalize_oop_references(method);
 531   // create nmethod
 532   nmethod* nm = NULL;
 533   {
 534     MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
 535     int nmethod_size = allocation_size(code_buffer, sizeof(nmethod));
 536     CodeOffsets offsets;
 537     offsets.set_value(CodeOffsets::Verified_Entry, vep_offset);
 538     offsets.set_value(CodeOffsets::Dtrace_trap, trap_offset);
 539     offsets.set_value(CodeOffsets::Frame_Complete, frame_complete);
 540 
 541     nm = new (nmethod_size) nmethod(method(), nmethod_size,
 542                                     &offsets, code_buffer, frame_size);
 543 
 544     NOT_PRODUCT(if (nm != NULL)  nmethod_stats.note_nmethod(nm));
 545     if (PrintAssembly && nm != NULL) {
 546       Disassembler::decode(nm);
 547     }
 548   }
 549   // verify nmethod
 550   debug_only(if (nm) nm->verify();) // might block
 551 
 552   if (nm != NULL) {
 553     nm->log_new_nmethod();
 554   }
 555 
 556   return nm;
 557 }
 558 
 559 #endif // def HAVE_DTRACE_H
 560 
 561 nmethod* nmethod::new_nmethod(methodHandle method,
 562   int compile_id,
 563   int entry_bci,
 564   CodeOffsets* offsets,
 565   int orig_pc_offset,
 566   DebugInformationRecorder* debug_info,
 567   Dependencies* dependencies,
 568   CodeBuffer* code_buffer, int frame_size,
 569   OopMapSet* oop_maps,
 570   ExceptionHandlerTable* handler_table,
 571   ImplicitExceptionTable* nul_chk_table,
 572   AbstractCompiler* compiler,
 573   int comp_level
 574 )
 575 {
 576   assert(debug_info->oop_recorder() == code_buffer->oop_recorder(), "shared OR");
 577   code_buffer->finalize_oop_references(method);
 578   // create nmethod
 579   nmethod* nm = NULL;
 580   { MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
 581     int nmethod_size =
 582       allocation_size(code_buffer, sizeof(nmethod))
 583       + adjust_pcs_size(debug_info->pcs_size())
 584       + round_to(dependencies->size_in_bytes() , oopSize)
 585       + round_to(handler_table->size_in_bytes(), oopSize)
 586       + round_to(nul_chk_table->size_in_bytes(), oopSize)
 587       + round_to(debug_info->data_size()       , oopSize);
 588 
 589     nm = new (nmethod_size)
 590     nmethod(method(), nmethod_size, compile_id, entry_bci, offsets,
 591             orig_pc_offset, debug_info, dependencies, code_buffer, frame_size,
 592             oop_maps,
 593             handler_table,
 594             nul_chk_table,
 595             compiler,
 596             comp_level);
 597 
 598     if (nm != NULL) {
 599       // To make dependency checking during class loading fast, record
 600       // the nmethod dependencies in the classes it is dependent on.
 601       // This allows the dependency checking code to simply walk the
 602       // class hierarchy above the loaded class, checking only nmethods
 603       // which are dependent on those classes.  The slow way is to
 604       // check every nmethod for dependencies which makes it linear in
 605       // the number of methods compiled.  For applications with a lot
 606       // classes the slow way is too slow.
 607       for (Dependencies::DepStream deps(nm); deps.next(); ) {
 608         Klass* klass = deps.context_type();
 609         if (klass == NULL) {
 610           continue;  // ignore things like evol_method
 611         }
 612 
 613         // record this nmethod as dependent on this klass
 614         InstanceKlass::cast(klass)->add_dependent_nmethod(nm);
 615       }
 616       NOT_PRODUCT(nmethod_stats.note_nmethod(nm));
 617       if (PrintAssembly || CompilerOracle::has_option_string(method, "PrintAssembly")) {
 618         Disassembler::decode(nm);
 619       }
 620     }
 621   }
 622   // Do verification and logging outside CodeCache_lock.
 623   if (nm != NULL) {
 624     // Safepoints in nmethod::verify aren't allowed because nm hasn't been installed yet.
 625     DEBUG_ONLY(nm->verify();)
 626     nm->log_new_nmethod();
 627   }
 628   return nm;
 629 }
 630 
 631 
 632 // For native wrappers
 633 nmethod::nmethod(
 634   Method* method,
 635   int nmethod_size,
 636   int compile_id,
 637   CodeOffsets* offsets,
 638   CodeBuffer* code_buffer,
 639   int frame_size,
 640   ByteSize basic_lock_owner_sp_offset,
 641   ByteSize basic_lock_sp_offset,
 642   OopMapSet* oop_maps )
 643   : CodeBlob("native nmethod", code_buffer, sizeof(nmethod),
 644              nmethod_size, offsets->value(CodeOffsets::Frame_Complete), frame_size, oop_maps),
 645   _native_receiver_sp_offset(basic_lock_owner_sp_offset),
 646   _native_basic_lock_sp_offset(basic_lock_sp_offset)
 647 {
 648   {
 649     debug_only(No_Safepoint_Verifier nsv;)
 650     assert_locked_or_safepoint(CodeCache_lock);
 651 
 652     init_defaults();
 653     _method                  = method;
 654     _entry_bci               = InvocationEntryBci;
 655     // We have no exception handler or deopt handler make the
 656     // values something that will never match a pc like the nmethod vtable entry
 657     _exception_offset        = 0;
 658     _deoptimize_offset       = 0;
 659     _deoptimize_mh_offset    = 0;
 660     _orig_pc_offset          = 0;
 661 
 662     _consts_offset           = data_offset();
 663     _stub_offset             = data_offset();
 664     _oops_offset             = data_offset();
 665     _metadata_offset         = _oops_offset         + round_to(code_buffer->total_oop_size(), oopSize);
 666     _scopes_data_offset      = _metadata_offset     + round_to(code_buffer->total_metadata_size(), wordSize);
 667     _scopes_pcs_offset       = _scopes_data_offset;
 668     _dependencies_offset     = _scopes_pcs_offset;
 669     _handler_table_offset    = _dependencies_offset;
 670     _nul_chk_table_offset    = _handler_table_offset;
 671     _nmethod_end_offset      = _nul_chk_table_offset;
 672     _compile_id              = compile_id;
 673     _comp_level              = CompLevel_none;
 674     _entry_point             = code_begin()          + offsets->value(CodeOffsets::Entry);
 675     _verified_entry_point    = code_begin()          + offsets->value(CodeOffsets::Verified_Entry);
 676     _osr_entry_point         = NULL;
 677     _exception_cache         = NULL;
 678     _pc_desc_cache.reset_to(NULL);
 679     _hotness_counter         = NMethodSweeper::hotness_counter_reset_val();
 680 
 681     code_buffer->copy_values_to(this);
 682     if (ScavengeRootsInCode) {
 683       if (detect_scavenge_root_oops()) {
 684         CodeCache::add_scavenge_root_nmethod(this);
 685       }
 686       Universe::heap()->register_nmethod(this);
 687     }
 688     debug_only(verify_scavenge_root_oops());
 689     CodeCache::commit(this);
 690   }
 691 
 692   if (PrintNativeNMethods || PrintDebugInfo || PrintRelocations || PrintDependencies) {
 693     ttyLocker ttyl;  // keep the following output all in one block
 694     // This output goes directly to the tty, not the compiler log.
 695     // To enable tools to match it up with the compilation activity,
 696     // be sure to tag this tty output with the compile ID.
 697     if (xtty != NULL) {
 698       xtty->begin_head("print_native_nmethod");
 699       xtty->method(_method);
 700       xtty->stamp();
 701       xtty->end_head(" address='" INTPTR_FORMAT "'", (intptr_t) this);
 702     }
 703     // print the header part first
 704     print();
 705     // then print the requested information
 706     if (PrintNativeNMethods) {
 707       print_code();
 708       if (oop_maps != NULL) {
 709         oop_maps->print();
 710       }
 711     }
 712     if (PrintRelocations) {
 713       print_relocations();
 714     }
 715     if (xtty != NULL) {
 716       xtty->tail("print_native_nmethod");
 717     }
 718   }
 719 }
 720 
 721 // For dtrace wrappers
 722 #ifdef HAVE_DTRACE_H
 723 nmethod::nmethod(
 724   Method* method,
 725   int nmethod_size,
 726   CodeOffsets* offsets,
 727   CodeBuffer* code_buffer,
 728   int frame_size)
 729   : CodeBlob("dtrace nmethod", code_buffer, sizeof(nmethod),
 730              nmethod_size, offsets->value(CodeOffsets::Frame_Complete), frame_size, NULL),
 731   _native_receiver_sp_offset(in_ByteSize(-1)),
 732   _native_basic_lock_sp_offset(in_ByteSize(-1))
 733 {
 734   {
 735     debug_only(No_Safepoint_Verifier nsv;)
 736     assert_locked_or_safepoint(CodeCache_lock);
 737 
 738     init_defaults();
 739     _method                  = method;
 740     _entry_bci               = InvocationEntryBci;
 741     // We have no exception handler or deopt handler make the
 742     // values something that will never match a pc like the nmethod vtable entry
 743     _exception_offset        = 0;
 744     _deoptimize_offset       = 0;
 745     _deoptimize_mh_offset    = 0;
 746     _unwind_handler_offset   = -1;
 747     _trap_offset             = offsets->value(CodeOffsets::Dtrace_trap);
 748     _orig_pc_offset          = 0;
 749     _consts_offset           = data_offset();
 750     _stub_offset             = data_offset();
 751     _oops_offset             = data_offset();
 752     _metadata_offset         = _oops_offset         + round_to(code_buffer->total_oop_size(), oopSize);
 753     _scopes_data_offset      = _metadata_offset     + round_to(code_buffer->total_metadata_size(), wordSize);
 754     _scopes_pcs_offset       = _scopes_data_offset;
 755     _dependencies_offset     = _scopes_pcs_offset;
 756     _handler_table_offset    = _dependencies_offset;
 757     _nul_chk_table_offset    = _handler_table_offset;
 758     _nmethod_end_offset      = _nul_chk_table_offset;
 759     _compile_id              = 0;  // default
 760     _comp_level              = CompLevel_none;
 761     _entry_point             = code_begin()          + offsets->value(CodeOffsets::Entry);
 762     _verified_entry_point    = code_begin()          + offsets->value(CodeOffsets::Verified_Entry);
 763     _osr_entry_point         = NULL;
 764     _exception_cache         = NULL;
 765     _pc_desc_cache.reset_to(NULL);
 766     _hotness_counter         = NMethodSweeper::hotness_counter_reset_val();
 767 
 768     code_buffer->copy_values_to(this);
 769     if (ScavengeRootsInCode) {
 770       if (detect_scavenge_root_oops()) {
 771         CodeCache::add_scavenge_root_nmethod(this);
 772       }
 773       Universe::heap()->register_nmethod(this);
 774     }
 775     DEBUG_ONLY(verify_scavenge_root_oops();)
 776     CodeCache::commit(this);
 777   }
 778 
 779   if (PrintNMethods || PrintDebugInfo || PrintRelocations || PrintDependencies) {
 780     ttyLocker ttyl;  // keep the following output all in one block
 781     // This output goes directly to the tty, not the compiler log.
 782     // To enable tools to match it up with the compilation activity,
 783     // be sure to tag this tty output with the compile ID.
 784     if (xtty != NULL) {
 785       xtty->begin_head("print_dtrace_nmethod");
 786       xtty->method(_method);
 787       xtty->stamp();
 788       xtty->end_head(" address='" INTPTR_FORMAT "'", (intptr_t) this);
 789     }
 790     // print the header part first
 791     print();
 792     // then print the requested information
 793     if (PrintNMethods) {
 794       print_code();
 795     }
 796     if (PrintRelocations) {
 797       print_relocations();
 798     }
 799     if (xtty != NULL) {
 800       xtty->tail("print_dtrace_nmethod");
 801     }
 802   }
 803 }
 804 #endif // def HAVE_DTRACE_H
 805 
 806 void* nmethod::operator new(size_t size, int nmethod_size) throw() {
 807   // Not critical, may return null if there is too little continuous memory
 808   return CodeCache::allocate(nmethod_size);
 809 }
 810 
 811 nmethod::nmethod(
 812   Method* method,
 813   int nmethod_size,
 814   int compile_id,
 815   int entry_bci,
 816   CodeOffsets* offsets,
 817   int orig_pc_offset,
 818   DebugInformationRecorder* debug_info,
 819   Dependencies* dependencies,
 820   CodeBuffer *code_buffer,
 821   int frame_size,
 822   OopMapSet* oop_maps,
 823   ExceptionHandlerTable* handler_table,
 824   ImplicitExceptionTable* nul_chk_table,
 825   AbstractCompiler* compiler,
 826   int comp_level
 827   )
 828   : CodeBlob("nmethod", code_buffer, sizeof(nmethod),
 829              nmethod_size, offsets->value(CodeOffsets::Frame_Complete), frame_size, oop_maps),
 830   _native_receiver_sp_offset(in_ByteSize(-1)),
 831   _native_basic_lock_sp_offset(in_ByteSize(-1))
 832 {
 833   assert(debug_info->oop_recorder() == code_buffer->oop_recorder(), "shared OR");
 834   {
 835     debug_only(No_Safepoint_Verifier nsv;)
 836     assert_locked_or_safepoint(CodeCache_lock);
 837 
 838     init_defaults();
 839     _method                  = method;
 840     _entry_bci               = entry_bci;
 841     _compile_id              = compile_id;
 842     _comp_level              = comp_level;
 843     _compiler                = compiler;
 844     _orig_pc_offset          = orig_pc_offset;
 845     _hotness_counter         = NMethodSweeper::hotness_counter_reset_val();
 846 
 847     // Section offsets
 848     _consts_offset           = content_offset()      + code_buffer->total_offset_of(code_buffer->consts());
 849     _stub_offset             = content_offset()      + code_buffer->total_offset_of(code_buffer->stubs());
 850 
 851     // Exception handler and deopt handler are in the stub section
 852     assert(offsets->value(CodeOffsets::Exceptions) != -1, "must be set");
 853     assert(offsets->value(CodeOffsets::Deopt     ) != -1, "must be set");
 854     _exception_offset        = _stub_offset          + offsets->value(CodeOffsets::Exceptions);
 855     _deoptimize_offset       = _stub_offset          + offsets->value(CodeOffsets::Deopt);
 856     if (offsets->value(CodeOffsets::DeoptMH) != -1) {
 857       _deoptimize_mh_offset  = _stub_offset          + offsets->value(CodeOffsets::DeoptMH);
 858     } else {
 859       _deoptimize_mh_offset  = -1;
 860     }
 861     if (offsets->value(CodeOffsets::UnwindHandler) != -1) {
 862       _unwind_handler_offset = code_offset()         + offsets->value(CodeOffsets::UnwindHandler);
 863     } else {
 864       _unwind_handler_offset = -1;
 865     }
 866 
 867     _oops_offset             = data_offset();
 868     _metadata_offset         = _oops_offset          + round_to(code_buffer->total_oop_size(), oopSize);
 869     _scopes_data_offset      = _metadata_offset      + round_to(code_buffer->total_metadata_size(), wordSize);
 870 
 871     _scopes_pcs_offset       = _scopes_data_offset   + round_to(debug_info->data_size       (), oopSize);
 872     _dependencies_offset     = _scopes_pcs_offset    + adjust_pcs_size(debug_info->pcs_size());
 873     _handler_table_offset    = _dependencies_offset  + round_to(dependencies->size_in_bytes (), oopSize);
 874     _nul_chk_table_offset    = _handler_table_offset + round_to(handler_table->size_in_bytes(), oopSize);
 875     _nmethod_end_offset      = _nul_chk_table_offset + round_to(nul_chk_table->size_in_bytes(), oopSize);
 876 
 877     _entry_point             = code_begin()          + offsets->value(CodeOffsets::Entry);
 878     _verified_entry_point    = code_begin()          + offsets->value(CodeOffsets::Verified_Entry);
 879     _osr_entry_point         = code_begin()          + offsets->value(CodeOffsets::OSR_Entry);
 880     _exception_cache         = NULL;
 881     _pc_desc_cache.reset_to(scopes_pcs_begin());
 882 
 883     // Copy contents of ScopeDescRecorder to nmethod
 884     code_buffer->copy_values_to(this);
 885     debug_info->copy_to(this);
 886     dependencies->copy_to(this);
 887     if (ScavengeRootsInCode) {
 888       if (detect_scavenge_root_oops()) {
 889         CodeCache::add_scavenge_root_nmethod(this);
 890       }
 891       Universe::heap()->register_nmethod(this);
 892     }
 893     debug_only(verify_scavenge_root_oops());
 894 
 895     CodeCache::commit(this);
 896 
 897     // Copy contents of ExceptionHandlerTable to nmethod
 898     handler_table->copy_to(this);
 899     nul_chk_table->copy_to(this);
 900 
 901     // we use the information of entry points to find out if a method is
 902     // static or non static
 903     assert(compiler->is_c2() ||
 904            _method->is_static() == (entry_point() == _verified_entry_point),
 905            " entry points must be same for static methods and vice versa");
 906   }
 907 
 908   bool printnmethods = PrintNMethods
 909     || CompilerOracle::should_print(_method)
 910     || CompilerOracle::has_option_string(_method, "PrintNMethods");
 911   if (printnmethods || PrintDebugInfo || PrintRelocations || PrintDependencies || PrintExceptionHandlers) {
 912     print_nmethod(printnmethods);
 913   }
 914 }
 915 
 916 
 917 // Print a short set of xml attributes to identify this nmethod.  The
 918 // output should be embedded in some other element.
 919 void nmethod::log_identity(xmlStream* log) const {
 920   log->print(" compile_id='%d'", compile_id());
 921   const char* nm_kind = compile_kind();
 922   if (nm_kind != NULL)  log->print(" compile_kind='%s'", nm_kind);
 923   if (compiler() != NULL) {
 924     log->print(" compiler='%s'", compiler()->name());
 925   }
 926   if (TieredCompilation) {
 927     log->print(" level='%d'", comp_level());
 928   }
 929 }
 930 
 931 
 932 #define LOG_OFFSET(log, name)                    \
 933   if ((intptr_t)name##_end() - (intptr_t)name##_begin()) \
 934     log->print(" " XSTR(name) "_offset='%d'"    , \
 935                (intptr_t)name##_begin() - (intptr_t)this)
 936 
 937 
 938 void nmethod::log_new_nmethod() const {
 939   if (LogCompilation && xtty != NULL) {
 940     ttyLocker ttyl;
 941     HandleMark hm;
 942     xtty->begin_elem("nmethod");
 943     log_identity(xtty);
 944     xtty->print(" entry='" INTPTR_FORMAT "' size='%d'", code_begin(), size());
 945     xtty->print(" address='" INTPTR_FORMAT "'", (intptr_t) this);
 946 
 947     LOG_OFFSET(xtty, relocation);
 948     LOG_OFFSET(xtty, consts);
 949     LOG_OFFSET(xtty, insts);
 950     LOG_OFFSET(xtty, stub);
 951     LOG_OFFSET(xtty, scopes_data);
 952     LOG_OFFSET(xtty, scopes_pcs);
 953     LOG_OFFSET(xtty, dependencies);
 954     LOG_OFFSET(xtty, handler_table);
 955     LOG_OFFSET(xtty, nul_chk_table);
 956     LOG_OFFSET(xtty, oops);
 957 
 958     xtty->method(method());
 959     xtty->stamp();
 960     xtty->end_elem();
 961   }
 962 }
 963 
 964 #undef LOG_OFFSET
 965 
 966 
 967 // Print out more verbose output usually for a newly created nmethod.
 968 void nmethod::print_on(outputStream* st, const char* msg) const {
 969   if (st != NULL) {
 970     ttyLocker ttyl;
 971     if (WizardMode) {
 972       CompileTask::print_compilation(st, this, msg, /*short_form:*/ true);
 973       st->print_cr(" (" INTPTR_FORMAT ")", this);
 974     } else {
 975       CompileTask::print_compilation(st, this, msg, /*short_form:*/ false);
 976     }
 977   }
 978 }
 979 
 980 
 981 void nmethod::print_nmethod(bool printmethod) {
 982   ttyLocker ttyl;  // keep the following output all in one block
 983   if (xtty != NULL) {
 984     xtty->begin_head("print_nmethod");
 985     xtty->stamp();
 986     xtty->end_head();
 987   }
 988   // print the header part first
 989   print();
 990   // then print the requested information
 991   if (printmethod) {
 992     print_code();
 993     print_pcs();
 994     if (oop_maps()) {
 995       oop_maps()->print();
 996     }
 997   }
 998   if (PrintDebugInfo) {
 999     print_scopes();
1000   }
1001   if (PrintRelocations) {
1002     print_relocations();
1003   }
1004   if (PrintDependencies) {
1005     print_dependencies();
1006   }
1007   if (PrintExceptionHandlers) {
1008     print_handler_table();
1009     print_nul_chk_table();
1010   }
1011   if (xtty != NULL) {
1012     xtty->tail("print_nmethod");
1013   }
1014 }
1015 
1016 
1017 // Promote one word from an assembly-time handle to a live embedded oop.
1018 inline void nmethod::initialize_immediate_oop(oop* dest, jobject handle) {
1019   if (handle == NULL ||
1020       // As a special case, IC oops are initialized to 1 or -1.
1021       handle == (jobject) Universe::non_oop_word()) {
1022     (*dest) = (oop) handle;
1023   } else {
1024     (*dest) = JNIHandles::resolve_non_null(handle);
1025   }
1026 }
1027 
1028 
1029 // Have to have the same name because it's called by a template
1030 void nmethod::copy_values(GrowableArray<jobject>* array) {
1031   int length = array->length();
1032   assert((address)(oops_begin() + length) <= (address)oops_end(), "oops big enough");
1033   oop* dest = oops_begin();
1034   for (int index = 0 ; index < length; index++) {
1035     initialize_immediate_oop(&dest[index], array->at(index));
1036   }
1037 
1038   // Now we can fix up all the oops in the code.  We need to do this
1039   // in the code because the assembler uses jobjects as placeholders.
1040   // The code and relocations have already been initialized by the
1041   // CodeBlob constructor, so it is valid even at this early point to
1042   // iterate over relocations and patch the code.
1043   fix_oop_relocations(NULL, NULL, /*initialize_immediates=*/ true);
1044 }
1045 
1046 void nmethod::copy_values(GrowableArray<Metadata*>* array) {
1047   int length = array->length();
1048   assert((address)(metadata_begin() + length) <= (address)metadata_end(), "big enough");
1049   Metadata** dest = metadata_begin();
1050   for (int index = 0 ; index < length; index++) {
1051     dest[index] = array->at(index);
1052   }
1053 }
1054 
1055 bool nmethod::is_at_poll_return(address pc) {
1056   RelocIterator iter(this, pc, pc+1);
1057   while (iter.next()) {
1058     if (iter.type() == relocInfo::poll_return_type)
1059       return true;
1060   }
1061   return false;
1062 }
1063 
1064 
1065 bool nmethod::is_at_poll_or_poll_return(address pc) {
1066   RelocIterator iter(this, pc, pc+1);
1067   while (iter.next()) {
1068     relocInfo::relocType t = iter.type();
1069     if (t == relocInfo::poll_return_type || t == relocInfo::poll_type)
1070       return true;
1071   }
1072   return false;
1073 }
1074 
1075 
1076 void nmethod::fix_oop_relocations(address begin, address end, bool initialize_immediates) {
1077   // re-patch all oop-bearing instructions, just in case some oops moved
1078   RelocIterator iter(this, begin, end);
1079   while (iter.next()) {
1080     if (iter.type() == relocInfo::oop_type) {
1081       oop_Relocation* reloc = iter.oop_reloc();
1082       if (initialize_immediates && reloc->oop_is_immediate()) {
1083         oop* dest = reloc->oop_addr();
1084         initialize_immediate_oop(dest, (jobject) *dest);
1085       }
1086       // Refresh the oop-related bits of this instruction.
1087       reloc->fix_oop_relocation();
1088     } else if (iter.type() == relocInfo::metadata_type) {
1089       metadata_Relocation* reloc = iter.metadata_reloc();
1090       reloc->fix_metadata_relocation();
1091     }
1092   }
1093 }
1094 
1095 
1096 void nmethod::verify_oop_relocations() {
1097   // Ensure sure that the code matches the current oop values
1098   RelocIterator iter(this, NULL, NULL);
1099   while (iter.next()) {
1100     if (iter.type() == relocInfo::oop_type) {
1101       oop_Relocation* reloc = iter.oop_reloc();
1102       if (!reloc->oop_is_immediate()) {
1103         reloc->verify_oop_relocation();
1104       }
1105     }
1106   }
1107 }
1108 
1109 
1110 ScopeDesc* nmethod::scope_desc_at(address pc) {
1111   PcDesc* pd = pc_desc_at(pc);
1112   guarantee(pd != NULL, "scope must be present");
1113   return new ScopeDesc(this, pd->scope_decode_offset(),
1114                        pd->obj_decode_offset(), pd->should_reexecute(),
1115                        pd->return_oop());
1116 }
1117 
1118 
1119 void nmethod::clear_inline_caches() {
1120   assert(SafepointSynchronize::is_at_safepoint(), "cleaning of IC's only allowed at safepoint");
1121   if (is_zombie()) {
1122     return;
1123   }
1124 
1125   RelocIterator iter(this);
1126   while (iter.next()) {
1127     iter.reloc()->clear_inline_cache();
1128   }
1129 }
1130 
1131 
1132 void nmethod::cleanup_inline_caches() {
1133 
1134   assert_locked_or_safepoint(CompiledIC_lock);
1135 
1136   // If the method is not entrant or zombie then a JMP is plastered over the
1137   // first few bytes.  If an oop in the old code was there, that oop
1138   // should not get GC'd.  Skip the first few bytes of oops on
1139   // not-entrant methods.
1140   address low_boundary = verified_entry_point();
1141   if (!is_in_use()) {
1142     low_boundary += NativeJump::instruction_size;
1143     // %%% Note:  On SPARC we patch only a 4-byte trap, not a full NativeJump.
1144     // This means that the low_boundary is going to be a little too high.
1145     // This shouldn't matter, since oops of non-entrant methods are never used.
1146     // In fact, why are we bothering to look at oops in a non-entrant method??
1147   }
1148 
1149   // Find all calls in an nmethod, and clear the ones that points to zombie methods
1150   ResourceMark rm;
1151   RelocIterator iter(this, low_boundary);
1152   while(iter.next()) {
1153     switch(iter.type()) {
1154       case relocInfo::virtual_call_type:
1155       case relocInfo::opt_virtual_call_type: {
1156         CompiledIC *ic = CompiledIC_at(&iter);
1157         // Ok, to lookup references to zombies here
1158         CodeBlob *cb = CodeCache::find_blob_unsafe(ic->ic_destination());
1159         if( cb != NULL && cb->is_nmethod() ) {
1160           nmethod* nm = (nmethod*)cb;
1161           // Clean inline caches pointing to both zombie and not_entrant methods
1162           if (!nm->is_in_use() || (nm->method()->code() != nm)) ic->set_to_clean();
1163         }
1164         break;
1165       }
1166       case relocInfo::static_call_type: {
1167         CompiledStaticCall *csc = compiledStaticCall_at(iter.reloc());
1168         CodeBlob *cb = CodeCache::find_blob_unsafe(csc->destination());
1169         if( cb != NULL && cb->is_nmethod() ) {
1170           nmethod* nm = (nmethod*)cb;
1171           // Clean inline caches pointing to both zombie and not_entrant methods
1172           if (!nm->is_in_use() || (nm->method()->code() != nm)) csc->set_to_clean();
1173         }
1174         break;
1175       }
1176     }
1177   }
1178 }
1179 
1180 void nmethod::verify_clean_inline_caches() {
1181   assert_locked_or_safepoint(CompiledIC_lock);
1182 
1183   // If the method is not entrant or zombie then a JMP is plastered over the
1184   // first few bytes.  If an oop in the old code was there, that oop
1185   // should not get GC'd.  Skip the first few bytes of oops on
1186   // not-entrant methods.
1187   address low_boundary = verified_entry_point();
1188   if (!is_in_use()) {
1189     low_boundary += NativeJump::instruction_size;
1190     // %%% Note:  On SPARC we patch only a 4-byte trap, not a full NativeJump.
1191     // This means that the low_boundary is going to be a little too high.
1192     // This shouldn't matter, since oops of non-entrant methods are never used.
1193     // In fact, why are we bothering to look at oops in a non-entrant method??
1194   }
1195 
1196   ResourceMark rm;
1197   RelocIterator iter(this, low_boundary);
1198   while(iter.next()) {
1199     switch(iter.type()) {
1200       case relocInfo::virtual_call_type:
1201       case relocInfo::opt_virtual_call_type: {
1202         CompiledIC *ic = CompiledIC_at(&iter);
1203         // Ok, to lookup references to zombies here
1204         CodeBlob *cb = CodeCache::find_blob_unsafe(ic->ic_destination());
1205         if( cb != NULL && cb->is_nmethod() ) {
1206           nmethod* nm = (nmethod*)cb;
1207           // Verify that inline caches pointing to both zombie and not_entrant methods are clean
1208           if (!nm->is_in_use() || (nm->method()->code() != nm)) {
1209             assert(ic->is_clean(), "IC should be clean");
1210           }
1211         }
1212         break;
1213       }
1214       case relocInfo::static_call_type: {
1215         CompiledStaticCall *csc = compiledStaticCall_at(iter.reloc());
1216         CodeBlob *cb = CodeCache::find_blob_unsafe(csc->destination());
1217         if( cb != NULL && cb->is_nmethod() ) {
1218           nmethod* nm = (nmethod*)cb;
1219           // Verify that inline caches pointing to both zombie and not_entrant methods are clean
1220           if (!nm->is_in_use() || (nm->method()->code() != nm)) {
1221             assert(csc->is_clean(), "IC should be clean");
1222           }
1223         }
1224         break;
1225       }
1226     }
1227   }
1228 }
1229 
1230 int nmethod::verify_icholder_relocations() {
1231   int count = 0;
1232 
1233   RelocIterator iter(this);
1234   while(iter.next()) {
1235     if (iter.type() == relocInfo::virtual_call_type) {
1236       if (CompiledIC::is_icholder_call_site(iter.virtual_call_reloc())) {
1237         CompiledIC *ic = CompiledIC_at(&iter);
1238         if (TraceCompiledIC) {
1239           tty->print("noticed icholder " INTPTR_FORMAT " ", p2i(ic->cached_icholder()));
1240           ic->print();
1241         }
1242         assert(ic->cached_icholder() != NULL, "must be non-NULL");
1243         count++;
1244       }
1245     }
1246   }
1247 
1248   return count;
1249 }
1250 
1251 // This is a private interface with the sweeper.
1252 void nmethod::mark_as_seen_on_stack() {
1253   assert(is_alive(), "Must be an alive method");
1254   // Set the traversal mark to ensure that the sweeper does 2
1255   // cleaning passes before moving to zombie.
1256   set_stack_traversal_mark(NMethodSweeper::traversal_count());
1257 }
1258 
1259 // Tell if a non-entrant method can be converted to a zombie (i.e.,
1260 // there are no activations on the stack, not in use by the VM,
1261 // and not in use by the ServiceThread)
1262 bool nmethod::can_not_entrant_be_converted() {
1263   assert(is_not_entrant(), "must be a non-entrant method");
1264 
1265   // Since the nmethod sweeper only does partial sweep the sweeper's traversal
1266   // count can be greater than the stack traversal count before it hits the
1267   // nmethod for the second time.
1268   return stack_traversal_mark()+1 < NMethodSweeper::traversal_count() &&
1269          !is_locked_by_vm();
1270 }
1271 
1272 void nmethod::inc_decompile_count() {
1273   if (!is_compiled_by_c2()) return;
1274   // Could be gated by ProfileTraps, but do not bother...
1275   Method* m = method();
1276   if (m == NULL)  return;
1277   MethodData* mdo = m->method_data();
1278   if (mdo == NULL)  return;
1279   // There is a benign race here.  See comments in methodData.hpp.
1280   mdo->inc_decompile_count();
1281 }
1282 
1283 void nmethod::increase_unloading_clock() {
1284   _global_unloading_clock++;
1285   if (_global_unloading_clock == 0) {
1286     // _nmethods are allocated with _unloading_clock == 0,
1287     // so 0 is never used as a clock value.
1288     _global_unloading_clock = 1;
1289   }
1290 }
1291 
1292 void nmethod::set_unloading_clock(unsigned char unloading_clock) {
1293   OrderAccess::release_store((volatile jubyte*)&_unloading_clock, unloading_clock);
1294 }
1295 
1296 unsigned char nmethod::unloading_clock() {
1297   return (unsigned char)OrderAccess::load_acquire((volatile jubyte*)&_unloading_clock);
1298 }
1299 
1300 void nmethod::make_unloaded(BoolObjectClosure* is_alive, oop cause) {
1301 
1302   post_compiled_method_unload();
1303 
1304   // Since this nmethod is being unloaded, make sure that dependencies
1305   // recorded in instanceKlasses get flushed and pass non-NULL closure to
1306   // indicate that this work is being done during a GC.
1307   assert(Universe::heap()->is_gc_active(), "should only be called during gc");
1308   assert(is_alive != NULL, "Should be non-NULL");
1309   // A non-NULL is_alive closure indicates that this is being called during GC.
1310   flush_dependencies(is_alive);
1311 
1312   // Break cycle between nmethod & method
1313   if (TraceClassUnloading && WizardMode) {
1314     tty->print_cr("[Class unloading: Making nmethod " INTPTR_FORMAT
1315                   " unloadable], Method*(" INTPTR_FORMAT
1316                   "), cause(" INTPTR_FORMAT ")",
1317                   this, (address)_method, (address)cause);
1318     if (!Universe::heap()->is_gc_active())
1319       cause->klass()->print();
1320   }
1321   // Unlink the osr method, so we do not look this up again
1322   if (is_osr_method()) {
1323     invalidate_osr_method();
1324   }
1325   // If _method is already NULL the Method* is about to be unloaded,
1326   // so we don't have to break the cycle. Note that it is possible to
1327   // have the Method* live here, in case we unload the nmethod because
1328   // it is pointing to some oop (other than the Method*) being unloaded.
1329   if (_method != NULL) {
1330     // OSR methods point to the Method*, but the Method* does not
1331     // point back!
1332     if (_method->code() == this) {
1333       _method->clear_code(); // Break a cycle
1334     }
1335     _method = NULL;            // Clear the method of this dead nmethod
1336   }
1337   // Make the class unloaded - i.e., change state and notify sweeper
1338   assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
1339   if (is_in_use()) {
1340     // Transitioning directly from live to unloaded -- so
1341     // we need to force a cache clean-up; remember this
1342     // for later on.
1343     CodeCache::set_needs_cache_clean(true);
1344   }
1345 
1346   // Unregister must be done before the state change
1347   Universe::heap()->unregister_nmethod(this);
1348 
1349   _state = unloaded;
1350 
1351   // Log the unloading.
1352   log_state_change();
1353 
1354   // The Method* is gone at this point
1355   assert(_method == NULL, "Tautology");
1356 
1357   set_osr_link(NULL);
1358   //set_scavenge_root_link(NULL); // done by prune_scavenge_root_nmethods
1359   NMethodSweeper::report_state_change(this);
1360 }
1361 
1362 void nmethod::invalidate_osr_method() {
1363   assert(_entry_bci != InvocationEntryBci, "wrong kind of nmethod");
1364   // Remove from list of active nmethods
1365   if (method() != NULL)
1366     method()->method_holder()->remove_osr_nmethod(this);
1367 }
1368 
1369 void nmethod::log_state_change() const {
1370   if (LogCompilation) {
1371     if (xtty != NULL) {
1372       ttyLocker ttyl;  // keep the following output all in one block
1373       if (_state == unloaded) {
1374         xtty->begin_elem("make_unloaded thread='" UINTX_FORMAT "'",
1375                          os::current_thread_id());
1376       } else {
1377         xtty->begin_elem("make_not_entrant thread='" UINTX_FORMAT "'%s",
1378                          os::current_thread_id(),
1379                          (_state == zombie ? " zombie='1'" : ""));
1380       }
1381       log_identity(xtty);
1382       xtty->stamp();
1383       xtty->end_elem();
1384     }
1385   }
1386   if (PrintCompilation && _state != unloaded) {
1387     print_on(tty, _state == zombie ? "made zombie" : "made not entrant");
1388   }
1389 }
1390 
1391 /**
1392  * Common functionality for both make_not_entrant and make_zombie
1393  */
1394 bool nmethod::make_not_entrant_or_zombie(unsigned int state) {
1395   assert(state == zombie || state == not_entrant, "must be zombie or not_entrant");
1396   assert(!is_zombie(), "should not already be a zombie");
1397 
1398   // Make sure neither the nmethod nor the method is flushed in case of a safepoint in code below.
1399   nmethodLocker nml(this);
1400   methodHandle the_method(method());
1401   No_Safepoint_Verifier nsv;
1402 
1403   // during patching, depending on the nmethod state we must notify the GC that
1404   // code has been unloaded, unregistering it. We cannot do this right while
1405   // holding the Patching_lock because we need to use the CodeCache_lock. This
1406   // would be prone to deadlocks.
1407   // This flag is used to remember whether we need to later lock and unregister.
1408   bool nmethod_needs_unregister = false;
1409 
1410   {
1411     // invalidate osr nmethod before acquiring the patching lock since
1412     // they both acquire leaf locks and we don't want a deadlock.
1413     // This logic is equivalent to the logic below for patching the
1414     // verified entry point of regular methods.
1415     if (is_osr_method()) {
1416       // this effectively makes the osr nmethod not entrant
1417       invalidate_osr_method();
1418     }
1419 
1420     // Enter critical section.  Does not block for safepoint.
1421     MutexLockerEx pl(Patching_lock, Mutex::_no_safepoint_check_flag);
1422 
1423     if (_state == state) {
1424       // another thread already performed this transition so nothing
1425       // to do, but return false to indicate this.
1426       return false;
1427     }
1428 
1429     // The caller can be calling the method statically or through an inline
1430     // cache call.
1431     if (!is_osr_method() && !is_not_entrant()) {
1432       NativeJump::patch_verified_entry(entry_point(), verified_entry_point(),
1433                   SharedRuntime::get_handle_wrong_method_stub());
1434     }
1435 
1436     if (is_in_use()) {
1437       // It's a true state change, so mark the method as decompiled.
1438       // Do it only for transition from alive.
1439       inc_decompile_count();
1440     }
1441 
1442     // If the state is becoming a zombie, signal to unregister the nmethod with
1443     // the heap.
1444     // This nmethod may have already been unloaded during a full GC.
1445     if ((state == zombie) && !is_unloaded()) {
1446       nmethod_needs_unregister = true;
1447     }
1448 
1449     // Must happen before state change. Otherwise we have a race condition in
1450     // nmethod::can_not_entrant_be_converted(). I.e., a method can immediately
1451     // transition its state from 'not_entrant' to 'zombie' without having to wait
1452     // for stack scanning.
1453     if (state == not_entrant) {
1454       mark_as_seen_on_stack();
1455       OrderAccess::storestore();
1456     }
1457 
1458     // Change state
1459     _state = state;
1460 
1461     // Log the transition once
1462     log_state_change();
1463 
1464     // Remove nmethod from method.
1465     // We need to check if both the _code and _from_compiled_code_entry_point
1466     // refer to this nmethod because there is a race in setting these two fields
1467     // in Method* as seen in bugid 4947125.
1468     // If the vep() points to the zombie nmethod, the memory for the nmethod
1469     // could be flushed and the compiler and vtable stubs could still call
1470     // through it.
1471     if (method() != NULL && (method()->code() == this ||
1472                              method()->from_compiled_entry() == verified_entry_point())) {
1473       HandleMark hm;
1474       method()->clear_code();
1475     }
1476   } // leave critical region under Patching_lock
1477 
1478   // When the nmethod becomes zombie it is no longer alive so the
1479   // dependencies must be flushed.  nmethods in the not_entrant
1480   // state will be flushed later when the transition to zombie
1481   // happens or they get unloaded.
1482   if (state == zombie) {
1483     {
1484       // Flushing dependecies must be done before any possible
1485       // safepoint can sneak in, otherwise the oops used by the
1486       // dependency logic could have become stale.
1487       MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
1488       if (nmethod_needs_unregister) {
1489         Universe::heap()->unregister_nmethod(this);
1490       }
1491       flush_dependencies(NULL);
1492     }
1493 
1494     // zombie only - if a JVMTI agent has enabled the CompiledMethodUnload
1495     // event and it hasn't already been reported for this nmethod then
1496     // report it now. The event may have been reported earilier if the GC
1497     // marked it for unloading). JvmtiDeferredEventQueue support means
1498     // we no longer go to a safepoint here.
1499     post_compiled_method_unload();
1500 
1501 #ifdef ASSERT
1502     // It's no longer safe to access the oops section since zombie
1503     // nmethods aren't scanned for GC.
1504     _oops_are_stale = true;
1505 #endif
1506      // the Method may be reclaimed by class unloading now that the
1507      // nmethod is in zombie state
1508     set_method(NULL);
1509   } else {
1510     assert(state == not_entrant, "other cases may need to be handled differently");
1511   }
1512 
1513   if (TraceCreateZombies) {
1514     tty->print_cr("nmethod <" INTPTR_FORMAT "> code made %s", this, (state == not_entrant) ? "not entrant" : "zombie");
1515   }
1516 
1517   NMethodSweeper::report_state_change(this);
1518   return true;
1519 }
1520 
1521 void nmethod::flush() {
1522   // Note that there are no valid oops in the nmethod anymore.
1523   assert(is_zombie() || (is_osr_method() && is_unloaded()), "must be a zombie method");
1524   assert(is_marked_for_reclamation() || (is_osr_method() && is_unloaded()), "must be marked for reclamation");
1525 
1526   assert (!is_locked_by_vm(), "locked methods shouldn't be flushed");
1527   assert_locked_or_safepoint(CodeCache_lock);
1528 
1529   // completely deallocate this method
1530   Events::log(JavaThread::current(), "flushing nmethod " INTPTR_FORMAT, this);
1531   if (PrintMethodFlushing) {
1532     tty->print_cr("*flushing nmethod %3d/" INTPTR_FORMAT ". Live blobs:" UINT32_FORMAT "/Free CodeCache:" SIZE_FORMAT "Kb",
1533         _compile_id, this, CodeCache::nof_blobs(), CodeCache::unallocated_capacity()/1024);
1534   }
1535 
1536   // We need to deallocate any ExceptionCache data.
1537   // Note that we do not need to grab the nmethod lock for this, it
1538   // better be thread safe if we're disposing of it!
1539   ExceptionCache* ec = exception_cache();
1540   set_exception_cache(NULL);
1541   while(ec != NULL) {
1542     ExceptionCache* next = ec->next();
1543     delete ec;
1544     ec = next;
1545   }
1546 
1547   if (on_scavenge_root_list()) {
1548     CodeCache::drop_scavenge_root_nmethod(this);
1549   }
1550 
1551 #ifdef SHARK
1552   ((SharkCompiler *) compiler())->free_compiled_method(insts_begin());
1553 #endif // SHARK
1554 
1555   ((CodeBlob*)(this))->flush();
1556 
1557   CodeCache::free(this);
1558 }
1559 
1560 
1561 //
1562 // Notify all classes this nmethod is dependent on that it is no
1563 // longer dependent. This should only be called in two situations.
1564 // First, when a nmethod transitions to a zombie all dependents need
1565 // to be clear.  Since zombification happens at a safepoint there's no
1566 // synchronization issues.  The second place is a little more tricky.
1567 // During phase 1 of mark sweep class unloading may happen and as a
1568 // result some nmethods may get unloaded.  In this case the flushing
1569 // of dependencies must happen during phase 1 since after GC any
1570 // dependencies in the unloaded nmethod won't be updated, so
1571 // traversing the dependency information in unsafe.  In that case this
1572 // function is called with a non-NULL argument and this function only
1573 // notifies instanceKlasses that are reachable
1574 
1575 void nmethod::flush_dependencies(BoolObjectClosure* is_alive) {
1576   assert_locked_or_safepoint(CodeCache_lock);
1577   assert(Universe::heap()->is_gc_active() == (is_alive != NULL),
1578   "is_alive is non-NULL if and only if we are called during GC");
1579   if (!has_flushed_dependencies()) {
1580     set_has_flushed_dependencies();
1581     for (Dependencies::DepStream deps(this); deps.next(); ) {
1582       Klass* klass = deps.context_type();
1583       if (klass == NULL)  continue;  // ignore things like evol_method
1584 
1585       // During GC the is_alive closure is non-NULL, and is used to
1586       // determine liveness of dependees that need to be updated.
1587       if (is_alive == NULL || klass->is_loader_alive(is_alive)) {
1588         InstanceKlass::cast(klass)->remove_dependent_nmethod(this);
1589       }
1590     }
1591   }
1592 }
1593 
1594 
1595 // If this oop is not live, the nmethod can be unloaded.
1596 bool nmethod::can_unload(BoolObjectClosure* is_alive, oop* root, bool unloading_occurred) {
1597   assert(root != NULL, "just checking");
1598   oop obj = *root;
1599   if (obj == NULL || is_alive->do_object_b(obj)) {
1600       return false;
1601   }
1602 
1603   // If ScavengeRootsInCode is true, an nmethod might be unloaded
1604   // simply because one of its constant oops has gone dead.
1605   // No actual classes need to be unloaded in order for this to occur.
1606   assert(unloading_occurred || ScavengeRootsInCode, "Inconsistency in unloading");
1607   make_unloaded(is_alive, obj);
1608   return true;
1609 }
1610 
1611 // ------------------------------------------------------------------
1612 // post_compiled_method_load_event
1613 // new method for install_code() path
1614 // Transfer information from compilation to jvmti
1615 void nmethod::post_compiled_method_load_event() {
1616 
1617   Method* moop = method();
1618   HOTSPOT_COMPILED_METHOD_LOAD(
1619       (char *) moop->klass_name()->bytes(),
1620       moop->klass_name()->utf8_length(),
1621       (char *) moop->name()->bytes(),
1622       moop->name()->utf8_length(),
1623       (char *) moop->signature()->bytes(),
1624       moop->signature()->utf8_length(),
1625       insts_begin(), insts_size());
1626 
1627   if (JvmtiExport::should_post_compiled_method_load() ||
1628       JvmtiExport::should_post_compiled_method_unload()) {
1629     get_and_cache_jmethod_id();
1630   }
1631 
1632   if (JvmtiExport::should_post_compiled_method_load()) {
1633     // Let the Service thread (which is a real Java thread) post the event
1634     MutexLockerEx ml(Service_lock, Mutex::_no_safepoint_check_flag);
1635     JvmtiDeferredEventQueue::enqueue(
1636       JvmtiDeferredEvent::compiled_method_load_event(this));
1637   }
1638 }
1639 
1640 jmethodID nmethod::get_and_cache_jmethod_id() {
1641   if (_jmethod_id == NULL) {
1642     // Cache the jmethod_id since it can no longer be looked up once the
1643     // method itself has been marked for unloading.
1644     _jmethod_id = method()->jmethod_id();
1645   }
1646   return _jmethod_id;
1647 }
1648 
1649 void nmethod::post_compiled_method_unload() {
1650   if (unload_reported()) {
1651     // During unloading we transition to unloaded and then to zombie
1652     // and the unloading is reported during the first transition.
1653     return;
1654   }
1655 
1656   assert(_method != NULL && !is_unloaded(), "just checking");
1657   DTRACE_METHOD_UNLOAD_PROBE(method());
1658 
1659   // If a JVMTI agent has enabled the CompiledMethodUnload event then
1660   // post the event. Sometime later this nmethod will be made a zombie
1661   // by the sweeper but the Method* will not be valid at that point.
1662   // If the _jmethod_id is null then no load event was ever requested
1663   // so don't bother posting the unload.  The main reason for this is
1664   // that the jmethodID is a weak reference to the Method* so if
1665   // it's being unloaded there's no way to look it up since the weak
1666   // ref will have been cleared.
1667   if (_jmethod_id != NULL && JvmtiExport::should_post_compiled_method_unload()) {
1668     assert(!unload_reported(), "already unloaded");
1669     JvmtiDeferredEvent event =
1670       JvmtiDeferredEvent::compiled_method_unload_event(this,
1671           _jmethod_id, insts_begin());
1672     if (SafepointSynchronize::is_at_safepoint()) {
1673       // Don't want to take the queueing lock. Add it as pending and
1674       // it will get enqueued later.
1675       JvmtiDeferredEventQueue::add_pending_event(event);
1676     } else {
1677       MutexLockerEx ml(Service_lock, Mutex::_no_safepoint_check_flag);
1678       JvmtiDeferredEventQueue::enqueue(event);
1679     }
1680   }
1681 
1682   // The JVMTI CompiledMethodUnload event can be enabled or disabled at
1683   // any time. As the nmethod is being unloaded now we mark it has
1684   // having the unload event reported - this will ensure that we don't
1685   // attempt to report the event in the unlikely scenario where the
1686   // event is enabled at the time the nmethod is made a zombie.
1687   set_unload_reported();
1688 }
1689 
1690 void static clean_ic_if_metadata_is_dead(CompiledIC *ic, BoolObjectClosure *is_alive) {
1691   if (ic->is_icholder_call()) {
1692     // The only exception is compiledICHolder oops which may
1693     // yet be marked below. (We check this further below).
1694     CompiledICHolder* cichk_oop = ic->cached_icholder();
1695     if (cichk_oop->holder_method()->method_holder()->is_loader_alive(is_alive) &&
1696         cichk_oop->holder_klass()->is_loader_alive(is_alive)) {
1697       return;
1698     }
1699   } else {
1700     Metadata* ic_oop = ic->cached_metadata();
1701     if (ic_oop != NULL) {
1702       if (ic_oop->is_klass()) {
1703         if (((Klass*)ic_oop)->is_loader_alive(is_alive)) {
1704           return;
1705         }
1706       } else if (ic_oop->is_method()) {
1707         if (((Method*)ic_oop)->method_holder()->is_loader_alive(is_alive)) {
1708           return;
1709         }
1710       } else {
1711         ShouldNotReachHere();
1712       }
1713     }
1714   }
1715 
1716   ic->set_to_clean();
1717 }
1718 
1719 // This is called at the end of the strong tracing/marking phase of a
1720 // GC to unload an nmethod if it contains otherwise unreachable
1721 // oops.
1722 
1723 void nmethod::do_unloading(BoolObjectClosure* is_alive, bool unloading_occurred) {
1724   // Make sure the oop's ready to receive visitors
1725   assert(!is_zombie() && !is_unloaded(),
1726          "should not call follow on zombie or unloaded nmethod");
1727 
1728   // If the method is not entrant then a JMP is plastered over the
1729   // first few bytes.  If an oop in the old code was there, that oop
1730   // should not get GC'd.  Skip the first few bytes of oops on
1731   // not-entrant methods.
1732   address low_boundary = verified_entry_point();
1733   if (is_not_entrant()) {
1734     low_boundary += NativeJump::instruction_size;
1735     // %%% Note:  On SPARC we patch only a 4-byte trap, not a full NativeJump.
1736     // (See comment above.)
1737   }
1738 
1739   // The RedefineClasses() API can cause the class unloading invariant
1740   // to no longer be true. See jvmtiExport.hpp for details.
1741   // Also, leave a debugging breadcrumb in local flag.
1742   bool a_class_was_redefined = JvmtiExport::has_redefined_a_class();
1743   if (a_class_was_redefined) {
1744     // This set of the unloading_occurred flag is done before the
1745     // call to post_compiled_method_unload() so that the unloading
1746     // of this nmethod is reported.
1747     unloading_occurred = true;
1748   }
1749 
1750   // Exception cache
1751   clean_exception_cache(is_alive);
1752 
1753   // If class unloading occurred we first iterate over all inline caches and
1754   // clear ICs where the cached oop is referring to an unloaded klass or method.
1755   // The remaining live cached oops will be traversed in the relocInfo::oop_type
1756   // iteration below.
1757   if (unloading_occurred) {
1758     RelocIterator iter(this, low_boundary);
1759     while(iter.next()) {
1760       if (iter.type() == relocInfo::virtual_call_type) {
1761         CompiledIC *ic = CompiledIC_at(&iter);
1762         clean_ic_if_metadata_is_dead(ic, is_alive);
1763       }
1764     }
1765   }
1766 
1767   // Compiled code
1768   {
1769   RelocIterator iter(this, low_boundary);
1770   while (iter.next()) {
1771     if (iter.type() == relocInfo::oop_type) {
1772       oop_Relocation* r = iter.oop_reloc();
1773       // In this loop, we must only traverse those oops directly embedded in
1774       // the code.  Other oops (oop_index>0) are seen as part of scopes_oops.
1775       assert(1 == (r->oop_is_immediate()) +
1776                   (r->oop_addr() >= oops_begin() && r->oop_addr() < oops_end()),
1777              "oop must be found in exactly one place");
1778       if (r->oop_is_immediate() && r->oop_value() != NULL) {
1779         if (can_unload(is_alive, r->oop_addr(), unloading_occurred)) {
1780           return;
1781         }
1782       }
1783     }
1784   }
1785   }
1786 
1787 
1788   // Scopes
1789   for (oop* p = oops_begin(); p < oops_end(); p++) {
1790     if (*p == Universe::non_oop_word())  continue;  // skip non-oops
1791     if (can_unload(is_alive, p, unloading_occurred)) {
1792       return;
1793     }
1794   }
1795 
1796   // Ensure that all metadata is still alive
1797   verify_metadata_loaders(low_boundary, is_alive);
1798 }
1799 
1800 template <class CompiledICorStaticCall>
1801 static bool clean_if_nmethod_is_unloaded(CompiledICorStaticCall *ic, address addr, BoolObjectClosure *is_alive, nmethod* from) {
1802   // Ok, to lookup references to zombies here
1803   CodeBlob *cb = CodeCache::find_blob_unsafe(addr);
1804   if (cb != NULL && cb->is_nmethod()) {
1805     nmethod* nm = (nmethod*)cb;
1806 
1807     if (nm->unloading_clock() != nmethod::global_unloading_clock()) {
1808       // The nmethod has not been processed yet.
1809       return true;
1810     }
1811 
1812     // Clean inline caches pointing to both zombie and not_entrant methods
1813     if (!nm->is_in_use() || (nm->method()->code() != nm)) {
1814       ic->set_to_clean();
1815       assert(ic->is_clean(), err_msg("nmethod " PTR_FORMAT "not clean %s", from, from->method()->name_and_sig_as_C_string()));
1816     }
1817   }
1818 
1819   return false;
1820 }
1821 
1822 static bool clean_if_nmethod_is_unloaded(CompiledIC *ic, BoolObjectClosure *is_alive, nmethod* from) {
1823   return clean_if_nmethod_is_unloaded(ic, ic->ic_destination(), is_alive, from);
1824 }
1825 
1826 static bool clean_if_nmethod_is_unloaded(CompiledStaticCall *csc, BoolObjectClosure *is_alive, nmethod* from) {
1827   return clean_if_nmethod_is_unloaded(csc, csc->destination(), is_alive, from);
1828 }
1829 
1830 bool nmethod::do_unloading_parallel(BoolObjectClosure* is_alive, bool unloading_occurred) {
1831   ResourceMark rm;
1832 
1833   // Make sure the oop's ready to receive visitors
1834   assert(!is_zombie() && !is_unloaded(),
1835          "should not call follow on zombie or unloaded nmethod");
1836 
1837   // If the method is not entrant then a JMP is plastered over the
1838   // first few bytes.  If an oop in the old code was there, that oop
1839   // should not get GC'd.  Skip the first few bytes of oops on
1840   // not-entrant methods.
1841   address low_boundary = verified_entry_point();
1842   if (is_not_entrant()) {
1843     low_boundary += NativeJump::instruction_size;
1844     // %%% Note:  On SPARC we patch only a 4-byte trap, not a full NativeJump.
1845     // (See comment above.)
1846   }
1847 
1848   // The RedefineClasses() API can cause the class unloading invariant
1849   // to no longer be true. See jvmtiExport.hpp for details.
1850   // Also, leave a debugging breadcrumb in local flag.
1851   bool a_class_was_redefined = JvmtiExport::has_redefined_a_class();
1852   if (a_class_was_redefined) {
1853     // This set of the unloading_occurred flag is done before the
1854     // call to post_compiled_method_unload() so that the unloading
1855     // of this nmethod is reported.
1856     unloading_occurred = true;
1857   }
1858 
1859   // Exception cache
1860   clean_exception_cache(is_alive);
1861 
1862   bool is_unloaded = false;
1863   bool postponed = false;
1864 
1865   RelocIterator iter(this, low_boundary);
1866   while(iter.next()) {
1867 
1868     switch (iter.type()) {
1869 
1870     case relocInfo::virtual_call_type:
1871       if (unloading_occurred) {
1872         // If class unloading occurred we first iterate over all inline caches and
1873         // clear ICs where the cached oop is referring to an unloaded klass or method.
1874         clean_ic_if_metadata_is_dead(CompiledIC_at(&iter), is_alive);
1875       }
1876 
1877       postponed |= clean_if_nmethod_is_unloaded(CompiledIC_at(&iter), is_alive, this);
1878       break;
1879 
1880     case relocInfo::opt_virtual_call_type:
1881       postponed |= clean_if_nmethod_is_unloaded(CompiledIC_at(&iter), is_alive, this);
1882       break;
1883 
1884     case relocInfo::static_call_type:
1885       postponed |= clean_if_nmethod_is_unloaded(compiledStaticCall_at(iter.reloc()), is_alive, this);
1886       break;
1887 
1888     case relocInfo::oop_type:
1889       if (!is_unloaded) {
1890         // Unload check
1891         oop_Relocation* r = iter.oop_reloc();
1892         // Traverse those oops directly embedded in the code.
1893         // Other oops (oop_index>0) are seen as part of scopes_oops.
1894         assert(1 == (r->oop_is_immediate()) +
1895                   (r->oop_addr() >= oops_begin() && r->oop_addr() < oops_end()),
1896               "oop must be found in exactly one place");
1897         if (r->oop_is_immediate() && r->oop_value() != NULL) {
1898           if (can_unload(is_alive, r->oop_addr(), unloading_occurred)) {
1899             is_unloaded = true;
1900           }
1901         }
1902       }
1903       break;
1904 
1905     }
1906   }
1907 
1908   if (is_unloaded) {
1909     return postponed;
1910   }
1911 
1912   // Scopes
1913   for (oop* p = oops_begin(); p < oops_end(); p++) {
1914     if (*p == Universe::non_oop_word())  continue;  // skip non-oops
1915     if (can_unload(is_alive, p, unloading_occurred)) {
1916       is_unloaded = true;
1917       break;
1918     }
1919   }
1920 
1921   if (is_unloaded) {
1922     return postponed;
1923   }
1924 
1925   // Ensure that all metadata is still alive
1926   verify_metadata_loaders(low_boundary, is_alive);
1927 
1928   return postponed;
1929 }
1930 
1931 void nmethod::do_unloading_parallel_postponed(BoolObjectClosure* is_alive, bool unloading_occurred) {
1932   ResourceMark rm;
1933 
1934   // Make sure the oop's ready to receive visitors
1935   assert(!is_zombie(),
1936          "should not call follow on zombie nmethod");
1937 
1938   // If the method is not entrant then a JMP is plastered over the
1939   // first few bytes.  If an oop in the old code was there, that oop
1940   // should not get GC'd.  Skip the first few bytes of oops on
1941   // not-entrant methods.
1942   address low_boundary = verified_entry_point();
1943   if (is_not_entrant()) {
1944     low_boundary += NativeJump::instruction_size;
1945     // %%% Note:  On SPARC we patch only a 4-byte trap, not a full NativeJump.
1946     // (See comment above.)
1947   }
1948 
1949   RelocIterator iter(this, low_boundary);
1950   while(iter.next()) {
1951 
1952     switch (iter.type()) {
1953 
1954     case relocInfo::virtual_call_type:
1955       clean_if_nmethod_is_unloaded(CompiledIC_at(&iter), is_alive, this);
1956       break;
1957 
1958     case relocInfo::opt_virtual_call_type:
1959       clean_if_nmethod_is_unloaded(CompiledIC_at(&iter), is_alive, this);
1960       break;
1961 
1962     case relocInfo::static_call_type:
1963       clean_if_nmethod_is_unloaded(compiledStaticCall_at(iter.reloc()), is_alive, this);
1964       break;
1965     }
1966   }
1967 }
1968 
1969 #ifdef ASSERT
1970 
1971 class CheckClass : AllStatic {
1972   static BoolObjectClosure* _is_alive;
1973 
1974   // Check class_loader is alive for this bit of metadata.
1975   static void check_class(Metadata* md) {
1976     Klass* klass = NULL;
1977     if (md->is_klass()) {
1978       klass = ((Klass*)md);
1979     } else if (md->is_method()) {
1980       klass = ((Method*)md)->method_holder();
1981     } else if (md->is_methodData()) {
1982       klass = ((MethodData*)md)->method()->method_holder();
1983     } else {
1984       md->print();
1985       ShouldNotReachHere();
1986     }
1987     assert(klass->is_loader_alive(_is_alive), "must be alive");
1988   }
1989  public:
1990   static void do_check_class(BoolObjectClosure* is_alive, nmethod* nm) {
1991     assert(SafepointSynchronize::is_at_safepoint(), "this is only ok at safepoint");
1992     _is_alive = is_alive;
1993     nm->metadata_do(check_class);
1994   }
1995 };
1996 
1997 // This is called during a safepoint so can use static data
1998 BoolObjectClosure* CheckClass::_is_alive = NULL;
1999 #endif // ASSERT
2000 
2001 
2002 // Processing of oop references should have been sufficient to keep
2003 // all strong references alive.  Any weak references should have been
2004 // cleared as well.  Visit all the metadata and ensure that it's
2005 // really alive.
2006 void nmethod::verify_metadata_loaders(address low_boundary, BoolObjectClosure* is_alive) {
2007 #ifdef ASSERT
2008     RelocIterator iter(this, low_boundary);
2009     while (iter.next()) {
2010     // static_stub_Relocations may have dangling references to
2011     // Method*s so trim them out here.  Otherwise it looks like
2012     // compiled code is maintaining a link to dead metadata.
2013     address static_call_addr = NULL;
2014     if (iter.type() == relocInfo::opt_virtual_call_type) {
2015       CompiledIC* cic = CompiledIC_at(&iter);
2016       if (!cic->is_call_to_interpreted()) {
2017         static_call_addr = iter.addr();
2018       }
2019     } else if (iter.type() == relocInfo::static_call_type) {
2020       CompiledStaticCall* csc = compiledStaticCall_at(iter.reloc());
2021       if (!csc->is_call_to_interpreted()) {
2022         static_call_addr = iter.addr();
2023       }
2024     }
2025     if (static_call_addr != NULL) {
2026       RelocIterator sciter(this, low_boundary);
2027       while (sciter.next()) {
2028         if (sciter.type() == relocInfo::static_stub_type &&
2029             sciter.static_stub_reloc()->static_call() == static_call_addr) {
2030           sciter.static_stub_reloc()->clear_inline_cache();
2031         }
2032       }
2033     }
2034   }
2035   // Check that the metadata embedded in the nmethod is alive
2036   CheckClass::do_check_class(is_alive, this);
2037 #endif
2038 }
2039 
2040 
2041 // Iterate over metadata calling this function.   Used by RedefineClasses
2042 void nmethod::metadata_do(void f(Metadata*)) {
2043   address low_boundary = verified_entry_point();
2044   if (is_not_entrant()) {
2045     low_boundary += NativeJump::instruction_size;
2046     // %%% Note:  On SPARC we patch only a 4-byte trap, not a full NativeJump.
2047     // (See comment above.)
2048   }
2049   {
2050     // Visit all immediate references that are embedded in the instruction stream.
2051     RelocIterator iter(this, low_boundary);
2052     while (iter.next()) {
2053       if (iter.type() == relocInfo::metadata_type ) {
2054         metadata_Relocation* r = iter.metadata_reloc();
2055         // In this lmetadata, we must only follow those metadatas directly embedded in
2056         // the code.  Other metadatas (oop_index>0) are seen as part of
2057         // the metadata section below.
2058         assert(1 == (r->metadata_is_immediate()) +
2059                (r->metadata_addr() >= metadata_begin() && r->metadata_addr() < metadata_end()),
2060                "metadata must be found in exactly one place");
2061         if (r->metadata_is_immediate() && r->metadata_value() != NULL) {
2062           Metadata* md = r->metadata_value();
2063           f(md);
2064         }
2065       } else if (iter.type() == relocInfo::virtual_call_type) {
2066         // Check compiledIC holders associated with this nmethod
2067         CompiledIC *ic = CompiledIC_at(&iter);
2068         if (ic->is_icholder_call()) {
2069           CompiledICHolder* cichk = ic->cached_icholder();
2070           f(cichk->holder_method());
2071           f(cichk->holder_klass());
2072         } else {
2073           Metadata* ic_oop = ic->cached_metadata();
2074           if (ic_oop != NULL) {
2075             f(ic_oop);
2076           }
2077         }
2078       }
2079     }
2080   }
2081 
2082   // Visit the metadata section
2083   for (Metadata** p = metadata_begin(); p < metadata_end(); p++) {
2084     if (*p == Universe::non_oop_word() || *p == NULL)  continue;  // skip non-oops
2085     Metadata* md = *p;
2086     f(md);
2087   }
2088 
2089   // Call function Method*, not embedded in these other places.
2090   if (_method != NULL) f(_method);
2091 }
2092 
2093 void nmethod::oops_do(OopClosure* f, bool allow_zombie) {
2094   // make sure the oops ready to receive visitors
2095   assert(allow_zombie || !is_zombie(), "should not call follow on zombie nmethod");
2096   assert(!is_unloaded(), "should not call follow on unloaded nmethod");
2097 
2098   // If the method is not entrant or zombie then a JMP is plastered over the
2099   // first few bytes.  If an oop in the old code was there, that oop
2100   // should not get GC'd.  Skip the first few bytes of oops on
2101   // not-entrant methods.
2102   address low_boundary = verified_entry_point();
2103   if (is_not_entrant()) {
2104     low_boundary += NativeJump::instruction_size;
2105     // %%% Note:  On SPARC we patch only a 4-byte trap, not a full NativeJump.
2106     // (See comment above.)
2107   }
2108 
2109   RelocIterator iter(this, low_boundary);
2110 
2111   while (iter.next()) {
2112     if (iter.type() == relocInfo::oop_type ) {
2113       oop_Relocation* r = iter.oop_reloc();
2114       // In this loop, we must only follow those oops directly embedded in
2115       // the code.  Other oops (oop_index>0) are seen as part of scopes_oops.
2116       assert(1 == (r->oop_is_immediate()) +
2117                    (r->oop_addr() >= oops_begin() && r->oop_addr() < oops_end()),
2118              "oop must be found in exactly one place");
2119       if (r->oop_is_immediate() && r->oop_value() != NULL) {
2120         f->do_oop(r->oop_addr());
2121       }
2122     }
2123   }
2124 
2125   // Scopes
2126   // This includes oop constants not inlined in the code stream.
2127   for (oop* p = oops_begin(); p < oops_end(); p++) {
2128     if (*p == Universe::non_oop_word())  continue;  // skip non-oops
2129     f->do_oop(p);
2130   }
2131 }
2132 
2133 #define NMETHOD_SENTINEL ((nmethod*)badAddress)
2134 
2135 nmethod* volatile nmethod::_oops_do_mark_nmethods;
2136 
2137 // An nmethod is "marked" if its _mark_link is set non-null.
2138 // Even if it is the end of the linked list, it will have a non-null link value,
2139 // as long as it is on the list.
2140 // This code must be MP safe, because it is used from parallel GC passes.
2141 bool nmethod::test_set_oops_do_mark() {
2142   assert(nmethod::oops_do_marking_is_active(), "oops_do_marking_prologue must be called");
2143   nmethod* observed_mark_link = _oops_do_mark_link;
2144   if (observed_mark_link == NULL) {
2145     // Claim this nmethod for this thread to mark.
2146     observed_mark_link = (nmethod*)
2147       Atomic::cmpxchg_ptr(NMETHOD_SENTINEL, &_oops_do_mark_link, NULL);
2148     if (observed_mark_link == NULL) {
2149 
2150       // Atomically append this nmethod (now claimed) to the head of the list:
2151       nmethod* observed_mark_nmethods = _oops_do_mark_nmethods;
2152       for (;;) {
2153         nmethod* required_mark_nmethods = observed_mark_nmethods;
2154         _oops_do_mark_link = required_mark_nmethods;
2155         observed_mark_nmethods = (nmethod*)
2156           Atomic::cmpxchg_ptr(this, &_oops_do_mark_nmethods, required_mark_nmethods);
2157         if (observed_mark_nmethods == required_mark_nmethods)
2158           break;
2159       }
2160       // Mark was clear when we first saw this guy.
2161       NOT_PRODUCT(if (TraceScavenge)  print_on(tty, "oops_do, mark"));
2162       return false;
2163     }
2164   }
2165   // On fall through, another racing thread marked this nmethod before we did.
2166   return true;
2167 }
2168 
2169 void nmethod::oops_do_marking_prologue() {
2170   NOT_PRODUCT(if (TraceScavenge)  tty->print_cr("[oops_do_marking_prologue"));
2171   assert(_oops_do_mark_nmethods == NULL, "must not call oops_do_marking_prologue twice in a row");
2172   // We use cmpxchg_ptr instead of regular assignment here because the user
2173   // may fork a bunch of threads, and we need them all to see the same state.
2174   void* observed = Atomic::cmpxchg_ptr(NMETHOD_SENTINEL, &_oops_do_mark_nmethods, NULL);
2175   guarantee(observed == NULL, "no races in this sequential code");
2176 }
2177 
2178 void nmethod::oops_do_marking_epilogue() {
2179   assert(_oops_do_mark_nmethods != NULL, "must not call oops_do_marking_epilogue twice in a row");
2180   nmethod* cur = _oops_do_mark_nmethods;
2181   while (cur != NMETHOD_SENTINEL) {
2182     assert(cur != NULL, "not NULL-terminated");
2183     nmethod* next = cur->_oops_do_mark_link;
2184     cur->_oops_do_mark_link = NULL;
2185     cur->verify_oop_relocations();
2186     NOT_PRODUCT(if (TraceScavenge)  cur->print_on(tty, "oops_do, unmark"));
2187     cur = next;
2188   }
2189   void* required = _oops_do_mark_nmethods;
2190   void* observed = Atomic::cmpxchg_ptr(NULL, &_oops_do_mark_nmethods, required);
2191   guarantee(observed == required, "no races in this sequential code");
2192   NOT_PRODUCT(if (TraceScavenge)  tty->print_cr("oops_do_marking_epilogue]"));
2193 }
2194 
2195 class DetectScavengeRoot: public OopClosure {
2196   bool     _detected_scavenge_root;
2197 public:
2198   DetectScavengeRoot() : _detected_scavenge_root(false)
2199   { NOT_PRODUCT(_print_nm = NULL); }
2200   bool detected_scavenge_root() { return _detected_scavenge_root; }
2201   virtual void do_oop(oop* p) {
2202     if ((*p) != NULL && (*p)->is_scavengable()) {
2203       NOT_PRODUCT(maybe_print(p));
2204       _detected_scavenge_root = true;
2205     }
2206   }
2207   virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
2208 
2209 #ifndef PRODUCT
2210   nmethod* _print_nm;
2211   void maybe_print(oop* p) {
2212     if (_print_nm == NULL)  return;
2213     if (!_detected_scavenge_root)  _print_nm->print_on(tty, "new scavenge root");
2214     tty->print_cr(""PTR_FORMAT"[offset=%d] detected scavengable oop "PTR_FORMAT" (found at "PTR_FORMAT")",
2215                   _print_nm, (int)((intptr_t)p - (intptr_t)_print_nm),
2216                   (void *)(*p), (intptr_t)p);
2217     (*p)->print();
2218   }
2219 #endif //PRODUCT
2220 };
2221 
2222 bool nmethod::detect_scavenge_root_oops() {
2223   DetectScavengeRoot detect_scavenge_root;
2224   NOT_PRODUCT(if (TraceScavenge)  detect_scavenge_root._print_nm = this);
2225   oops_do(&detect_scavenge_root);
2226   return detect_scavenge_root.detected_scavenge_root();
2227 }
2228 
2229 // Method that knows how to preserve outgoing arguments at call. This method must be
2230 // called with a frame corresponding to a Java invoke
2231 void nmethod::preserve_callee_argument_oops(frame fr, const RegisterMap *reg_map, OopClosure* f) {
2232 #ifndef SHARK
2233   if (!method()->is_native()) {
2234     SimpleScopeDesc ssd(this, fr.pc());
2235     Bytecode_invoke call(ssd.method(), ssd.bci());
2236     bool has_receiver = call.has_receiver();
2237     bool has_appendix = call.has_appendix();
2238     Symbol* signature = call.signature();
2239     fr.oops_compiled_arguments_do(signature, has_receiver, has_appendix, reg_map, f);
2240   }
2241 #endif // !SHARK
2242 }
2243 
2244 
2245 oop nmethod::embeddedOop_at(u_char* p) {
2246   RelocIterator iter(this, p, p + 1);
2247   while (iter.next())
2248     if (iter.type() == relocInfo::oop_type) {
2249       return iter.oop_reloc()->oop_value();
2250     }
2251   return NULL;
2252 }
2253 
2254 
2255 inline bool includes(void* p, void* from, void* to) {
2256   return from <= p && p < to;
2257 }
2258 
2259 
2260 void nmethod::copy_scopes_pcs(PcDesc* pcs, int count) {
2261   assert(count >= 2, "must be sentinel values, at least");
2262 
2263 #ifdef ASSERT
2264   // must be sorted and unique; we do a binary search in find_pc_desc()
2265   int prev_offset = pcs[0].pc_offset();
2266   assert(prev_offset == PcDesc::lower_offset_limit,
2267          "must start with a sentinel");
2268   for (int i = 1; i < count; i++) {
2269     int this_offset = pcs[i].pc_offset();
2270     assert(this_offset > prev_offset, "offsets must be sorted");
2271     prev_offset = this_offset;
2272   }
2273   assert(prev_offset == PcDesc::upper_offset_limit,
2274          "must end with a sentinel");
2275 #endif //ASSERT
2276 
2277   // Search for MethodHandle invokes and tag the nmethod.
2278   for (int i = 0; i < count; i++) {
2279     if (pcs[i].is_method_handle_invoke()) {
2280       set_has_method_handle_invokes(true);
2281       break;
2282     }
2283   }
2284   assert(has_method_handle_invokes() == (_deoptimize_mh_offset != -1), "must have deopt mh handler");
2285 
2286   int size = count * sizeof(PcDesc);
2287   assert(scopes_pcs_size() >= size, "oob");
2288   memcpy(scopes_pcs_begin(), pcs, size);
2289 
2290   // Adjust the final sentinel downward.
2291   PcDesc* last_pc = &scopes_pcs_begin()[count-1];
2292   assert(last_pc->pc_offset() == PcDesc::upper_offset_limit, "sanity");
2293   last_pc->set_pc_offset(content_size() + 1);
2294   for (; last_pc + 1 < scopes_pcs_end(); last_pc += 1) {
2295     // Fill any rounding gaps with copies of the last record.
2296     last_pc[1] = last_pc[0];
2297   }
2298   // The following assert could fail if sizeof(PcDesc) is not
2299   // an integral multiple of oopSize (the rounding term).
2300   // If it fails, change the logic to always allocate a multiple
2301   // of sizeof(PcDesc), and fill unused words with copies of *last_pc.
2302   assert(last_pc + 1 == scopes_pcs_end(), "must match exactly");
2303 }
2304 
2305 void nmethod::copy_scopes_data(u_char* buffer, int size) {
2306   assert(scopes_data_size() >= size, "oob");
2307   memcpy(scopes_data_begin(), buffer, size);
2308 }
2309 
2310 
2311 #ifdef ASSERT
2312 static PcDesc* linear_search(nmethod* nm, int pc_offset, bool approximate) {
2313   PcDesc* lower = nm->scopes_pcs_begin();
2314   PcDesc* upper = nm->scopes_pcs_end();
2315   lower += 1; // exclude initial sentinel
2316   PcDesc* res = NULL;
2317   for (PcDesc* p = lower; p < upper; p++) {
2318     NOT_PRODUCT(--nmethod_stats.pc_desc_tests);  // don't count this call to match_desc
2319     if (match_desc(p, pc_offset, approximate)) {
2320       if (res == NULL)
2321         res = p;
2322       else
2323         res = (PcDesc*) badAddress;
2324     }
2325   }
2326   return res;
2327 }
2328 #endif
2329 
2330 
2331 // Finds a PcDesc with real-pc equal to "pc"
2332 PcDesc* nmethod::find_pc_desc_internal(address pc, bool approximate) {
2333   address base_address = code_begin();
2334   if ((pc < base_address) ||
2335       (pc - base_address) >= (ptrdiff_t) PcDesc::upper_offset_limit) {
2336     return NULL;  // PC is wildly out of range
2337   }
2338   int pc_offset = (int) (pc - base_address);
2339 
2340   // Check the PcDesc cache if it contains the desired PcDesc
2341   // (This as an almost 100% hit rate.)
2342   PcDesc* res = _pc_desc_cache.find_pc_desc(pc_offset, approximate);
2343   if (res != NULL) {
2344     assert(res == linear_search(this, pc_offset, approximate), "cache ok");
2345     return res;
2346   }
2347 
2348   // Fallback algorithm: quasi-linear search for the PcDesc
2349   // Find the last pc_offset less than the given offset.
2350   // The successor must be the required match, if there is a match at all.
2351   // (Use a fixed radix to avoid expensive affine pointer arithmetic.)
2352   PcDesc* lower = scopes_pcs_begin();
2353   PcDesc* upper = scopes_pcs_end();
2354   upper -= 1; // exclude final sentinel
2355   if (lower >= upper)  return NULL;  // native method; no PcDescs at all
2356 
2357 #define assert_LU_OK \
2358   /* invariant on lower..upper during the following search: */ \
2359   assert(lower->pc_offset() <  pc_offset, "sanity"); \
2360   assert(upper->pc_offset() >= pc_offset, "sanity")
2361   assert_LU_OK;
2362 
2363   // Use the last successful return as a split point.
2364   PcDesc* mid = _pc_desc_cache.last_pc_desc();
2365   NOT_PRODUCT(++nmethod_stats.pc_desc_searches);
2366   if (mid->pc_offset() < pc_offset) {
2367     lower = mid;
2368   } else {
2369     upper = mid;
2370   }
2371 
2372   // Take giant steps at first (4096, then 256, then 16, then 1)
2373   const int LOG2_RADIX = 4 /*smaller steps in debug mode:*/ debug_only(-1);
2374   const int RADIX = (1 << LOG2_RADIX);
2375   for (int step = (1 << (LOG2_RADIX*3)); step > 1; step >>= LOG2_RADIX) {
2376     while ((mid = lower + step) < upper) {
2377       assert_LU_OK;
2378       NOT_PRODUCT(++nmethod_stats.pc_desc_searches);
2379       if (mid->pc_offset() < pc_offset) {
2380         lower = mid;
2381       } else {
2382         upper = mid;
2383         break;
2384       }
2385     }
2386     assert_LU_OK;
2387   }
2388 
2389   // Sneak up on the value with a linear search of length ~16.
2390   while (true) {
2391     assert_LU_OK;
2392     mid = lower + 1;
2393     NOT_PRODUCT(++nmethod_stats.pc_desc_searches);
2394     if (mid->pc_offset() < pc_offset) {
2395       lower = mid;
2396     } else {
2397       upper = mid;
2398       break;
2399     }
2400   }
2401 #undef assert_LU_OK
2402 
2403   if (match_desc(upper, pc_offset, approximate)) {
2404     assert(upper == linear_search(this, pc_offset, approximate), "search ok");
2405     _pc_desc_cache.add_pc_desc(upper);
2406     return upper;
2407   } else {
2408     assert(NULL == linear_search(this, pc_offset, approximate), "search ok");
2409     return NULL;
2410   }
2411 }
2412 
2413 
2414 void nmethod::check_all_dependencies(DepChange& changes) {
2415   // Checked dependencies are allocated into this ResourceMark
2416   ResourceMark rm;
2417 
2418   // Turn off dependency tracing while actually testing dependencies.
2419   NOT_PRODUCT( FlagSetting fs(TraceDependencies, false) );
2420 
2421  typedef ResourceHashtable<DependencySignature, int, &DependencySignature::hash,
2422                            &DependencySignature::equals, 11027> DepTable;
2423 
2424  DepTable* table = new DepTable();
2425 
2426   // Iterate over live nmethods and check dependencies of all nmethods that are not
2427   // marked for deoptimization. A particular dependency is only checked once.
2428   for(nmethod* nm = CodeCache::alive_nmethod(CodeCache::first()); nm != NULL; nm = CodeCache::alive_nmethod(CodeCache::next(nm))) {
2429     if (!nm->is_marked_for_deoptimization()) {
2430       for (Dependencies::DepStream deps(nm); deps.next(); ) {
2431         // Construct abstraction of a dependency.
2432         DependencySignature* current_sig = new DependencySignature(deps);
2433 
2434         // Determine if dependency is already checked. table->put(...) returns
2435         // 'true' if the dependency is added (i.e., was not in the hashtable).
2436         if (table->put(*current_sig, 1)) {
2437           if (deps.check_dependency() != NULL) {
2438             // Dependency checking failed. Print out information about the failed
2439             // dependency and finally fail with an assert. We can fail here, since
2440             // dependency checking is never done in a product build.
2441             changes.print();
2442             nm->print();
2443             nm->print_dependencies();
2444             assert(false, "Should have been marked for deoptimization");
2445           }
2446         }
2447       }
2448     }
2449   }
2450 }
2451 
2452 bool nmethod::check_dependency_on(DepChange& changes) {
2453   // What has happened:
2454   // 1) a new class dependee has been added
2455   // 2) dependee and all its super classes have been marked
2456   bool found_check = false;  // set true if we are upset
2457   for (Dependencies::DepStream deps(this); deps.next(); ) {
2458     // Evaluate only relevant dependencies.
2459     if (deps.spot_check_dependency_at(changes) != NULL) {
2460       found_check = true;
2461       NOT_DEBUG(break);
2462     }
2463   }
2464   return found_check;
2465 }
2466 
2467 bool nmethod::is_evol_dependent_on(Klass* dependee) {
2468   InstanceKlass *dependee_ik = InstanceKlass::cast(dependee);
2469   Array<Method*>* dependee_methods = dependee_ik->methods();
2470   for (Dependencies::DepStream deps(this); deps.next(); ) {
2471     if (deps.type() == Dependencies::evol_method) {
2472       Method* method = deps.method_argument(0);
2473       for (int j = 0; j < dependee_methods->length(); j++) {
2474         if (dependee_methods->at(j) == method) {
2475           // RC_TRACE macro has an embedded ResourceMark
2476           RC_TRACE(0x01000000,
2477             ("Found evol dependency of nmethod %s.%s(%s) compile_id=%d on method %s.%s(%s)",
2478             _method->method_holder()->external_name(),
2479             _method->name()->as_C_string(),
2480             _method->signature()->as_C_string(), compile_id(),
2481             method->method_holder()->external_name(),
2482             method->name()->as_C_string(),
2483             method->signature()->as_C_string()));
2484           if (TraceDependencies || LogCompilation)
2485             deps.log_dependency(dependee);
2486           return true;
2487         }
2488       }
2489     }
2490   }
2491   return false;
2492 }
2493 
2494 // Called from mark_for_deoptimization, when dependee is invalidated.
2495 bool nmethod::is_dependent_on_method(Method* dependee) {
2496   for (Dependencies::DepStream deps(this); deps.next(); ) {
2497     if (deps.type() != Dependencies::evol_method)
2498       continue;
2499     Method* method = deps.method_argument(0);
2500     if (method == dependee) return true;
2501   }
2502   return false;
2503 }
2504 
2505 
2506 bool nmethod::is_patchable_at(address instr_addr) {
2507   assert(insts_contains(instr_addr), "wrong nmethod used");
2508   if (is_zombie()) {
2509     // a zombie may never be patched
2510     return false;
2511   }
2512   return true;
2513 }
2514 
2515 
2516 address nmethod::continuation_for_implicit_exception(address pc) {
2517   // Exception happened outside inline-cache check code => we are inside
2518   // an active nmethod => use cpc to determine a return address
2519   int exception_offset = pc - code_begin();
2520   int cont_offset = ImplicitExceptionTable(this).at( exception_offset );
2521 #ifdef ASSERT
2522   if (cont_offset == 0) {
2523     Thread* thread = ThreadLocalStorage::get_thread_slow();
2524     ResetNoHandleMark rnm; // Might be called from LEAF/QUICK ENTRY
2525     HandleMark hm(thread);
2526     ResourceMark rm(thread);
2527     CodeBlob* cb = CodeCache::find_blob(pc);
2528     assert(cb != NULL && cb == this, "");
2529     tty->print_cr("implicit exception happened at " INTPTR_FORMAT, pc);
2530     print();
2531     method()->print_codes();
2532     print_code();
2533     print_pcs();
2534   }
2535 #endif
2536   if (cont_offset == 0) {
2537     // Let the normal error handling report the exception
2538     return NULL;
2539   }
2540   return code_begin() + cont_offset;
2541 }
2542 
2543 
2544 
2545 void nmethod_init() {
2546   // make sure you didn't forget to adjust the filler fields
2547   assert(sizeof(nmethod) % oopSize == 0, "nmethod size must be multiple of a word");
2548 }
2549 
2550 
2551 //-------------------------------------------------------------------------------------------
2552 
2553 
2554 // QQQ might we make this work from a frame??
2555 nmethodLocker::nmethodLocker(address pc) {
2556   CodeBlob* cb = CodeCache::find_blob(pc);
2557   guarantee(cb != NULL && cb->is_nmethod(), "bad pc for a nmethod found");
2558   _nm = (nmethod*)cb;
2559   lock_nmethod(_nm);
2560 }
2561 
2562 // Only JvmtiDeferredEvent::compiled_method_unload_event()
2563 // should pass zombie_ok == true.
2564 void nmethodLocker::lock_nmethod(nmethod* nm, bool zombie_ok) {
2565   if (nm == NULL)  return;
2566   Atomic::inc(&nm->_lock_count);
2567   assert(zombie_ok || !nm->is_zombie(), "cannot lock a zombie method");
2568 }
2569 
2570 void nmethodLocker::unlock_nmethod(nmethod* nm) {
2571   if (nm == NULL)  return;
2572   Atomic::dec(&nm->_lock_count);
2573   assert(nm->_lock_count >= 0, "unmatched nmethod lock/unlock");
2574 }
2575 
2576 
2577 // -----------------------------------------------------------------------------
2578 // nmethod::get_deopt_original_pc
2579 //
2580 // Return the original PC for the given PC if:
2581 // (a) the given PC belongs to a nmethod and
2582 // (b) it is a deopt PC
2583 address nmethod::get_deopt_original_pc(const frame* fr) {
2584   if (fr->cb() == NULL)  return NULL;
2585 
2586   nmethod* nm = fr->cb()->as_nmethod_or_null();
2587   if (nm != NULL && nm->is_deopt_pc(fr->pc()))
2588     return nm->get_original_pc(fr);
2589 
2590   return NULL;
2591 }
2592 
2593 
2594 // -----------------------------------------------------------------------------
2595 // MethodHandle
2596 
2597 bool nmethod::is_method_handle_return(address return_pc) {
2598   if (!has_method_handle_invokes())  return false;
2599   PcDesc* pd = pc_desc_at(return_pc);
2600   if (pd == NULL)
2601     return false;
2602   return pd->is_method_handle_invoke();
2603 }
2604 
2605 
2606 // -----------------------------------------------------------------------------
2607 // Verification
2608 
2609 class VerifyOopsClosure: public OopClosure {
2610   nmethod* _nm;
2611   bool     _ok;
2612 public:
2613   VerifyOopsClosure(nmethod* nm) : _nm(nm), _ok(true) { }
2614   bool ok() { return _ok; }
2615   virtual void do_oop(oop* p) {
2616     if ((*p) == NULL || (*p)->is_oop())  return;
2617     if (_ok) {
2618       _nm->print_nmethod(true);
2619       _ok = false;
2620     }
2621     tty->print_cr("*** non-oop "PTR_FORMAT" found at "PTR_FORMAT" (offset %d)",
2622                   (void *)(*p), (intptr_t)p, (int)((intptr_t)p - (intptr_t)_nm));
2623   }
2624   virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
2625 };
2626 
2627 void nmethod::verify() {
2628 
2629   // Hmm. OSR methods can be deopted but not marked as zombie or not_entrant
2630   // seems odd.
2631 
2632   if( is_zombie() || is_not_entrant() )
2633     return;
2634 
2635   // Make sure all the entry points are correctly aligned for patching.
2636   NativeJump::check_verified_entry_alignment(entry_point(), verified_entry_point());
2637 
2638   // assert(method()->is_oop(), "must be valid");
2639 
2640   ResourceMark rm;
2641 
2642   if (!CodeCache::contains(this)) {
2643     fatal(err_msg("nmethod at " INTPTR_FORMAT " not in zone", this));
2644   }
2645 
2646   if(is_native_method() )
2647     return;
2648 
2649   nmethod* nm = CodeCache::find_nmethod(verified_entry_point());
2650   if (nm != this) {
2651     fatal(err_msg("findNMethod did not find this nmethod (" INTPTR_FORMAT ")",
2652                   this));
2653   }
2654 
2655   for (PcDesc* p = scopes_pcs_begin(); p < scopes_pcs_end(); p++) {
2656     if (! p->verify(this)) {
2657       tty->print_cr("\t\tin nmethod at " INTPTR_FORMAT " (pcs)", this);
2658     }
2659   }
2660 
2661   VerifyOopsClosure voc(this);
2662   oops_do(&voc);
2663   assert(voc.ok(), "embedded oops must be OK");
2664   verify_scavenge_root_oops();
2665 
2666   verify_scopes();
2667 }
2668 
2669 
2670 void nmethod::verify_interrupt_point(address call_site) {
2671   // Verify IC only when nmethod installation is finished.
2672   bool is_installed = (method()->code() == this) // nmethod is in state 'in_use' and installed
2673                       || !this->is_in_use();     // nmethod is installed, but not in 'in_use' state
2674   if (is_installed) {
2675     Thread *cur = Thread::current();
2676     if (CompiledIC_lock->owner() == cur ||
2677         ((cur->is_VM_thread() || cur->is_ConcurrentGC_thread()) &&
2678          SafepointSynchronize::is_at_safepoint())) {
2679       CompiledIC_at(this, call_site);
2680       CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops());
2681     } else {
2682       MutexLocker ml_verify (CompiledIC_lock);
2683       CompiledIC_at(this, call_site);
2684     }
2685   }
2686 
2687   PcDesc* pd = pc_desc_at(nativeCall_at(call_site)->return_address());
2688   assert(pd != NULL, "PcDesc must exist");
2689   for (ScopeDesc* sd = new ScopeDesc(this, pd->scope_decode_offset(),
2690                                      pd->obj_decode_offset(), pd->should_reexecute(),
2691                                      pd->return_oop());
2692        !sd->is_top(); sd = sd->sender()) {
2693     sd->verify();
2694   }
2695 }
2696 
2697 void nmethod::verify_scopes() {
2698   if( !method() ) return;       // Runtime stubs have no scope
2699   if (method()->is_native()) return; // Ignore stub methods.
2700   // iterate through all interrupt point
2701   // and verify the debug information is valid.
2702   RelocIterator iter((nmethod*)this);
2703   while (iter.next()) {
2704     address stub = NULL;
2705     switch (iter.type()) {
2706       case relocInfo::virtual_call_type:
2707         verify_interrupt_point(iter.addr());
2708         break;
2709       case relocInfo::opt_virtual_call_type:
2710         stub = iter.opt_virtual_call_reloc()->static_stub();
2711         verify_interrupt_point(iter.addr());
2712         break;
2713       case relocInfo::static_call_type:
2714         stub = iter.static_call_reloc()->static_stub();
2715         //verify_interrupt_point(iter.addr());
2716         break;
2717       case relocInfo::runtime_call_type:
2718         address destination = iter.reloc()->value();
2719         // Right now there is no way to find out which entries support
2720         // an interrupt point.  It would be nice if we had this
2721         // information in a table.
2722         break;
2723     }
2724     assert(stub == NULL || stub_contains(stub), "static call stub outside stub section");
2725   }
2726 }
2727 
2728 
2729 // -----------------------------------------------------------------------------
2730 // Non-product code
2731 #ifndef PRODUCT
2732 
2733 class DebugScavengeRoot: public OopClosure {
2734   nmethod* _nm;
2735   bool     _ok;
2736 public:
2737   DebugScavengeRoot(nmethod* nm) : _nm(nm), _ok(true) { }
2738   bool ok() { return _ok; }
2739   virtual void do_oop(oop* p) {
2740     if ((*p) == NULL || !(*p)->is_scavengable())  return;
2741     if (_ok) {
2742       _nm->print_nmethod(true);
2743       _ok = false;
2744     }
2745     tty->print_cr("*** scavengable oop "PTR_FORMAT" found at "PTR_FORMAT" (offset %d)",
2746                   (void *)(*p), (intptr_t)p, (int)((intptr_t)p - (intptr_t)_nm));
2747     (*p)->print();
2748   }
2749   virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
2750 };
2751 
2752 void nmethod::verify_scavenge_root_oops() {
2753   if (UseG1GC) {
2754     return;
2755   }
2756 
2757   if (!on_scavenge_root_list()) {
2758     // Actually look inside, to verify the claim that it's clean.
2759     DebugScavengeRoot debug_scavenge_root(this);
2760     oops_do(&debug_scavenge_root);
2761     if (!debug_scavenge_root.ok())
2762       fatal("found an unadvertised bad scavengable oop in the code cache");
2763   }
2764   assert(scavenge_root_not_marked(), "");
2765 }
2766 
2767 #endif // PRODUCT
2768 
2769 // Printing operations
2770 
2771 void nmethod::print() const {
2772   ResourceMark rm;
2773   ttyLocker ttyl;   // keep the following output all in one block
2774 
2775   tty->print("Compiled method ");
2776 
2777   if (is_compiled_by_c1()) {
2778     tty->print("(c1) ");
2779   } else if (is_compiled_by_c2()) {
2780     tty->print("(c2) ");
2781   } else if (is_compiled_by_shark()) {
2782     tty->print("(shark) ");
2783   } else {
2784     tty->print("(nm) ");
2785   }
2786 
2787   print_on(tty, NULL);
2788 
2789   if (WizardMode) {
2790     tty->print("((nmethod*) "INTPTR_FORMAT ") ", this);
2791     tty->print(" for method " INTPTR_FORMAT , (address)method());
2792     tty->print(" { ");
2793     if (is_in_use())      tty->print("in_use ");
2794     if (is_not_entrant()) tty->print("not_entrant ");
2795     if (is_zombie())      tty->print("zombie ");
2796     if (is_unloaded())    tty->print("unloaded ");
2797     if (on_scavenge_root_list())  tty->print("scavenge_root ");
2798     tty->print_cr("}:");
2799   }
2800   if (size              () > 0) tty->print_cr(" total in heap  [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2801                                               (address)this,
2802                                               (address)this + size(),
2803                                               size());
2804   if (relocation_size   () > 0) tty->print_cr(" relocation     [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2805                                               relocation_begin(),
2806                                               relocation_end(),
2807                                               relocation_size());
2808   if (consts_size       () > 0) tty->print_cr(" constants      [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2809                                               consts_begin(),
2810                                               consts_end(),
2811                                               consts_size());
2812   if (insts_size        () > 0) tty->print_cr(" main code      [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2813                                               insts_begin(),
2814                                               insts_end(),
2815                                               insts_size());
2816   if (stub_size         () > 0) tty->print_cr(" stub code      [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2817                                               stub_begin(),
2818                                               stub_end(),
2819                                               stub_size());
2820   if (oops_size         () > 0) tty->print_cr(" oops           [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2821                                               oops_begin(),
2822                                               oops_end(),
2823                                               oops_size());
2824   if (metadata_size      () > 0) tty->print_cr(" metadata       [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2825                                               metadata_begin(),
2826                                               metadata_end(),
2827                                               metadata_size());
2828   if (scopes_data_size  () > 0) tty->print_cr(" scopes data    [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2829                                               scopes_data_begin(),
2830                                               scopes_data_end(),
2831                                               scopes_data_size());
2832   if (scopes_pcs_size   () > 0) tty->print_cr(" scopes pcs     [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2833                                               scopes_pcs_begin(),
2834                                               scopes_pcs_end(),
2835                                               scopes_pcs_size());
2836   if (dependencies_size () > 0) tty->print_cr(" dependencies   [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2837                                               dependencies_begin(),
2838                                               dependencies_end(),
2839                                               dependencies_size());
2840   if (handler_table_size() > 0) tty->print_cr(" handler table  [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2841                                               handler_table_begin(),
2842                                               handler_table_end(),
2843                                               handler_table_size());
2844   if (nul_chk_table_size() > 0) tty->print_cr(" nul chk table  [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2845                                               nul_chk_table_begin(),
2846                                               nul_chk_table_end(),
2847                                               nul_chk_table_size());
2848 }
2849 
2850 void nmethod::print_code() {
2851   HandleMark hm;
2852   ResourceMark m;
2853   Disassembler::decode(this);
2854 }
2855 
2856 
2857 #ifndef PRODUCT
2858 
2859 void nmethod::print_scopes() {
2860   // Find the first pc desc for all scopes in the code and print it.
2861   ResourceMark rm;
2862   for (PcDesc* p = scopes_pcs_begin(); p < scopes_pcs_end(); p++) {
2863     if (p->scope_decode_offset() == DebugInformationRecorder::serialized_null)
2864       continue;
2865 
2866     ScopeDesc* sd = scope_desc_at(p->real_pc(this));
2867     sd->print_on(tty, p);
2868   }
2869 }
2870 
2871 void nmethod::print_dependencies() {
2872   ResourceMark rm;
2873   ttyLocker ttyl;   // keep the following output all in one block
2874   tty->print_cr("Dependencies:");
2875   for (Dependencies::DepStream deps(this); deps.next(); ) {
2876     deps.print_dependency();
2877     Klass* ctxk = deps.context_type();
2878     if (ctxk != NULL) {
2879       if (ctxk->oop_is_instance() && ((InstanceKlass*)ctxk)->is_dependent_nmethod(this)) {
2880         tty->print_cr("   [nmethod<=klass]%s", ctxk->external_name());
2881       }
2882     }
2883     deps.log_dependency();  // put it into the xml log also
2884   }
2885 }
2886 
2887 
2888 void nmethod::print_relocations() {
2889   ResourceMark m;       // in case methods get printed via the debugger
2890   tty->print_cr("relocations:");
2891   RelocIterator iter(this);
2892   iter.print();
2893   if (UseRelocIndex) {
2894     jint* index_end   = (jint*)relocation_end() - 1;
2895     jint  index_size  = *index_end;
2896     jint* index_start = (jint*)( (address)index_end - index_size );
2897     tty->print_cr("    index @" INTPTR_FORMAT ": index_size=%d", index_start, index_size);
2898     if (index_size > 0) {
2899       jint* ip;
2900       for (ip = index_start; ip+2 <= index_end; ip += 2)
2901         tty->print_cr("  (%d %d) addr=" INTPTR_FORMAT " @" INTPTR_FORMAT,
2902                       ip[0],
2903                       ip[1],
2904                       header_end()+ip[0],
2905                       relocation_begin()-1+ip[1]);
2906       for (; ip < index_end; ip++)
2907         tty->print_cr("  (%d ?)", ip[0]);
2908       tty->print_cr("          @" INTPTR_FORMAT ": index_size=%d", ip, *ip);
2909       ip++;
2910       tty->print_cr("reloc_end @" INTPTR_FORMAT ":", ip);
2911     }
2912   }
2913 }
2914 
2915 
2916 void nmethod::print_pcs() {
2917   ResourceMark m;       // in case methods get printed via debugger
2918   tty->print_cr("pc-bytecode offsets:");
2919   for (PcDesc* p = scopes_pcs_begin(); p < scopes_pcs_end(); p++) {
2920     p->print(this);
2921   }
2922 }
2923 
2924 #endif // PRODUCT
2925 
2926 const char* nmethod::reloc_string_for(u_char* begin, u_char* end) {
2927   RelocIterator iter(this, begin, end);
2928   bool have_one = false;
2929   while (iter.next()) {
2930     have_one = true;
2931     switch (iter.type()) {
2932         case relocInfo::none:                  return "no_reloc";
2933         case relocInfo::oop_type: {
2934           stringStream st;
2935           oop_Relocation* r = iter.oop_reloc();
2936           oop obj = r->oop_value();
2937           st.print("oop(");
2938           if (obj == NULL) st.print("NULL");
2939           else obj->print_value_on(&st);
2940           st.print(")");
2941           return st.as_string();
2942         }
2943         case relocInfo::metadata_type: {
2944           stringStream st;
2945           metadata_Relocation* r = iter.metadata_reloc();
2946           Metadata* obj = r->metadata_value();
2947           st.print("metadata(");
2948           if (obj == NULL) st.print("NULL");
2949           else obj->print_value_on(&st);
2950           st.print(")");
2951           return st.as_string();
2952         }
2953         case relocInfo::virtual_call_type:     return "virtual_call";
2954         case relocInfo::opt_virtual_call_type: return "optimized virtual_call";
2955         case relocInfo::static_call_type:      return "static_call";
2956         case relocInfo::static_stub_type:      return "static_stub";
2957         case relocInfo::runtime_call_type:     return "runtime_call";
2958         case relocInfo::external_word_type:    return "external_word";
2959         case relocInfo::internal_word_type:    return "internal_word";
2960         case relocInfo::section_word_type:     return "section_word";
2961         case relocInfo::poll_type:             return "poll";
2962         case relocInfo::poll_return_type:      return "poll_return";
2963         case relocInfo::type_mask:             return "type_bit_mask";
2964     }
2965   }
2966   return have_one ? "other" : NULL;
2967 }
2968 
2969 // Return a the last scope in (begin..end]
2970 ScopeDesc* nmethod::scope_desc_in(address begin, address end) {
2971   PcDesc* p = pc_desc_near(begin+1);
2972   if (p != NULL && p->real_pc(this) <= end) {
2973     return new ScopeDesc(this, p->scope_decode_offset(),
2974                          p->obj_decode_offset(), p->should_reexecute(),
2975                          p->return_oop());
2976   }
2977   return NULL;
2978 }
2979 
2980 void nmethod::print_nmethod_labels(outputStream* stream, address block_begin) const {
2981   if (block_begin == entry_point())             stream->print_cr("[Entry Point]");
2982   if (block_begin == verified_entry_point())    stream->print_cr("[Verified Entry Point]");
2983   if (block_begin == exception_begin())         stream->print_cr("[Exception Handler]");
2984   if (block_begin == stub_begin())              stream->print_cr("[Stub Code]");
2985   if (block_begin == deopt_handler_begin())     stream->print_cr("[Deopt Handler Code]");
2986 
2987   if (has_method_handle_invokes())
2988     if (block_begin == deopt_mh_handler_begin())  stream->print_cr("[Deopt MH Handler Code]");
2989 
2990   if (block_begin == consts_begin())            stream->print_cr("[Constants]");
2991 
2992   if (block_begin == entry_point()) {
2993     methodHandle m = method();
2994     if (m.not_null()) {
2995       stream->print("  # ");
2996       m->print_value_on(stream);
2997       stream->cr();
2998     }
2999     if (m.not_null() && !is_osr_method()) {
3000       ResourceMark rm;
3001       int sizeargs = m->size_of_parameters();
3002       BasicType* sig_bt = NEW_RESOURCE_ARRAY(BasicType, sizeargs);
3003       VMRegPair* regs   = NEW_RESOURCE_ARRAY(VMRegPair, sizeargs);
3004       {
3005         int sig_index = 0;
3006         if (!m->is_static())
3007           sig_bt[sig_index++] = T_OBJECT; // 'this'
3008         for (SignatureStream ss(m->signature()); !ss.at_return_type(); ss.next()) {
3009           BasicType t = ss.type();
3010           sig_bt[sig_index++] = t;
3011           if (type2size[t] == 2) {
3012             sig_bt[sig_index++] = T_VOID;
3013           } else {
3014             assert(type2size[t] == 1, "size is 1 or 2");
3015           }
3016         }
3017         assert(sig_index == sizeargs, "");
3018       }
3019       const char* spname = "sp"; // make arch-specific?
3020       intptr_t out_preserve = SharedRuntime::java_calling_convention(sig_bt, regs, sizeargs, false);
3021       int stack_slot_offset = this->frame_size() * wordSize;
3022       int tab1 = 14, tab2 = 24;
3023       int sig_index = 0;
3024       int arg_index = (m->is_static() ? 0 : -1);
3025       bool did_old_sp = false;
3026       for (SignatureStream ss(m->signature()); !ss.at_return_type(); ) {
3027         bool at_this = (arg_index == -1);
3028         bool at_old_sp = false;
3029         BasicType t = (at_this ? T_OBJECT : ss.type());
3030         assert(t == sig_bt[sig_index], "sigs in sync");
3031         if (at_this)
3032           stream->print("  # this: ");
3033         else
3034           stream->print("  # parm%d: ", arg_index);
3035         stream->move_to(tab1);
3036         VMReg fst = regs[sig_index].first();
3037         VMReg snd = regs[sig_index].second();
3038         if (fst->is_reg()) {
3039           stream->print("%s", fst->name());
3040           if (snd->is_valid())  {
3041             stream->print(":%s", snd->name());
3042           }
3043         } else if (fst->is_stack()) {
3044           int offset = fst->reg2stack() * VMRegImpl::stack_slot_size + stack_slot_offset;
3045           if (offset == stack_slot_offset)  at_old_sp = true;
3046           stream->print("[%s+0x%x]", spname, offset);
3047         } else {
3048           stream->print("reg%d:%d??", (int)(intptr_t)fst, (int)(intptr_t)snd);
3049         }
3050         stream->print(" ");
3051         stream->move_to(tab2);
3052         stream->print("= ");
3053         if (at_this) {
3054           m->method_holder()->print_value_on(stream);
3055         } else {
3056           bool did_name = false;
3057           if (!at_this && ss.is_object()) {
3058             Symbol* name = ss.as_symbol_or_null();
3059             if (name != NULL) {
3060               name->print_value_on(stream);
3061               did_name = true;
3062             }
3063           }
3064           if (!did_name)
3065             stream->print("%s", type2name(t));
3066         }
3067         if (at_old_sp) {
3068           stream->print("  (%s of caller)", spname);
3069           did_old_sp = true;
3070         }
3071         stream->cr();
3072         sig_index += type2size[t];
3073         arg_index += 1;
3074         if (!at_this)  ss.next();
3075       }
3076       if (!did_old_sp) {
3077         stream->print("  # ");
3078         stream->move_to(tab1);
3079         stream->print("[%s+0x%x]", spname, stack_slot_offset);
3080         stream->print("  (%s of caller)", spname);
3081         stream->cr();
3082       }
3083     }
3084   }
3085 }
3086 
3087 void nmethod::print_code_comment_on(outputStream* st, int column, u_char* begin, u_char* end) {
3088   // First, find an oopmap in (begin, end].
3089   // We use the odd half-closed interval so that oop maps and scope descs
3090   // which are tied to the byte after a call are printed with the call itself.
3091   address base = code_begin();
3092   OopMapSet* oms = oop_maps();
3093   if (oms != NULL) {
3094     for (int i = 0, imax = oms->size(); i < imax; i++) {
3095       OopMap* om = oms->at(i);
3096       address pc = base + om->offset();
3097       if (pc > begin) {
3098         if (pc <= end) {
3099           st->move_to(column);
3100           st->print("; ");
3101           om->print_on(st);
3102         }
3103         break;
3104       }
3105     }
3106   }
3107 
3108   // Print any debug info present at this pc.
3109   ScopeDesc* sd  = scope_desc_in(begin, end);
3110   if (sd != NULL) {
3111     st->move_to(column);
3112     if (sd->bci() == SynchronizationEntryBCI) {
3113       st->print(";*synchronization entry");
3114     } else {
3115       if (sd->method() == NULL) {
3116         st->print("method is NULL");
3117       } else if (sd->method()->is_native()) {
3118         st->print("method is native");
3119       } else {
3120         Bytecodes::Code bc = sd->method()->java_code_at(sd->bci());
3121         st->print(";*%s", Bytecodes::name(bc));
3122         switch (bc) {
3123         case Bytecodes::_invokevirtual:
3124         case Bytecodes::_invokespecial:
3125         case Bytecodes::_invokestatic:
3126         case Bytecodes::_invokeinterface:
3127           {
3128             Bytecode_invoke invoke(sd->method(), sd->bci());
3129             st->print(" ");
3130             if (invoke.name() != NULL)
3131               invoke.name()->print_symbol_on(st);
3132             else
3133               st->print("<UNKNOWN>");
3134             break;
3135           }
3136         case Bytecodes::_getfield:
3137         case Bytecodes::_putfield:
3138         case Bytecodes::_getstatic:
3139         case Bytecodes::_putstatic:
3140           {
3141             Bytecode_field field(sd->method(), sd->bci());
3142             st->print(" ");
3143             if (field.name() != NULL)
3144               field.name()->print_symbol_on(st);
3145             else
3146               st->print("<UNKNOWN>");
3147           }
3148         }
3149       }
3150     }
3151 
3152     // Print all scopes
3153     for (;sd != NULL; sd = sd->sender()) {
3154       st->move_to(column);
3155       st->print("; -");
3156       if (sd->method() == NULL) {
3157         st->print("method is NULL");
3158       } else {
3159         sd->method()->print_short_name(st);
3160       }
3161       int lineno = sd->method()->line_number_from_bci(sd->bci());
3162       if (lineno != -1) {
3163         st->print("@%d (line %d)", sd->bci(), lineno);
3164       } else {
3165         st->print("@%d", sd->bci());
3166       }
3167       st->cr();
3168     }
3169   }
3170 
3171   // Print relocation information
3172   const char* str = reloc_string_for(begin, end);
3173   if (str != NULL) {
3174     if (sd != NULL) st->cr();
3175     st->move_to(column);
3176     st->print(";   {%s}", str);
3177   }
3178   int cont_offset = ImplicitExceptionTable(this).at(begin - code_begin());
3179   if (cont_offset != 0) {
3180     st->move_to(column);
3181     st->print("; implicit exception: dispatches to " INTPTR_FORMAT, code_begin() + cont_offset);
3182   }
3183 
3184 }
3185 
3186 #ifndef PRODUCT
3187 
3188 void nmethod::print_value_on(outputStream* st) const {
3189   st->print("nmethod");
3190   print_on(st, NULL);
3191 }
3192 
3193 void nmethod::print_calls(outputStream* st) {
3194   RelocIterator iter(this);
3195   while (iter.next()) {
3196     switch (iter.type()) {
3197     case relocInfo::virtual_call_type:
3198     case relocInfo::opt_virtual_call_type: {
3199       VerifyMutexLocker mc(CompiledIC_lock);
3200       CompiledIC_at(&iter)->print();
3201       break;
3202     }
3203     case relocInfo::static_call_type:
3204       st->print_cr("Static call at " INTPTR_FORMAT, iter.reloc()->addr());
3205       compiledStaticCall_at(iter.reloc())->print();
3206       break;
3207     }
3208   }
3209 }
3210 
3211 void nmethod::print_handler_table() {
3212   ExceptionHandlerTable(this).print();
3213 }
3214 
3215 void nmethod::print_nul_chk_table() {
3216   ImplicitExceptionTable(this).print(code_begin());
3217 }
3218 
3219 void nmethod::print_statistics() {
3220   ttyLocker ttyl;
3221   if (xtty != NULL)  xtty->head("statistics type='nmethod'");
3222   nmethod_stats.print_native_nmethod_stats();
3223   nmethod_stats.print_nmethod_stats();
3224   DebugInformationRecorder::print_statistics();
3225   nmethod_stats.print_pc_stats();
3226   Dependencies::print_statistics();
3227   if (xtty != NULL)  xtty->tail("statistics");
3228 }
3229 
3230 #endif // PRODUCT