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   // Set entry as invalid
1368   _entry_bci = InvalidOSREntryBci;
1369 }
1370 
1371 void nmethod::log_state_change() const {
1372   if (LogCompilation) {
1373     if (xtty != NULL) {
1374       ttyLocker ttyl;  // keep the following output all in one block
1375       if (_state == unloaded) {
1376         xtty->begin_elem("make_unloaded thread='" UINTX_FORMAT "'",
1377                          os::current_thread_id());
1378       } else {
1379         xtty->begin_elem("make_not_entrant thread='" UINTX_FORMAT "'%s",
1380                          os::current_thread_id(),
1381                          (_state == zombie ? " zombie='1'" : ""));
1382       }
1383       log_identity(xtty);
1384       xtty->stamp();
1385       xtty->end_elem();
1386     }
1387   }
1388   if (PrintCompilation && _state != unloaded) {
1389     print_on(tty, _state == zombie ? "made zombie" : "made not entrant");
1390   }
1391 }
1392 
1393 /**
1394  * Common functionality for both make_not_entrant and make_zombie
1395  */
1396 bool nmethod::make_not_entrant_or_zombie(unsigned int state) {
1397   assert(state == zombie || state == not_entrant, "must be zombie or not_entrant");
1398   assert(!is_zombie(), "should not already be a zombie");
1399 
1400   // Make sure neither the nmethod nor the method is flushed in case of a safepoint in code below.
1401   nmethodLocker nml(this);
1402   methodHandle the_method(method());
1403   No_Safepoint_Verifier nsv;
1404 
1405   // during patching, depending on the nmethod state we must notify the GC that
1406   // code has been unloaded, unregistering it. We cannot do this right while
1407   // holding the Patching_lock because we need to use the CodeCache_lock. This
1408   // would be prone to deadlocks.
1409   // This flag is used to remember whether we need to later lock and unregister.
1410   bool nmethod_needs_unregister = false;
1411 
1412   {
1413     // invalidate osr nmethod before acquiring the patching lock since
1414     // they both acquire leaf locks and we don't want a deadlock.
1415     // This logic is equivalent to the logic below for patching the
1416     // verified entry point of regular methods.
1417     if (is_osr_method()) {
1418       // this effectively makes the osr nmethod not entrant
1419       invalidate_osr_method();
1420     }
1421 
1422     // Enter critical section.  Does not block for safepoint.
1423     MutexLockerEx pl(Patching_lock, Mutex::_no_safepoint_check_flag);
1424 
1425     if (_state == state) {
1426       // another thread already performed this transition so nothing
1427       // to do, but return false to indicate this.
1428       return false;
1429     }
1430 
1431     // The caller can be calling the method statically or through an inline
1432     // cache call.
1433     if (!is_osr_method() && !is_not_entrant()) {
1434       NativeJump::patch_verified_entry(entry_point(), verified_entry_point(),
1435                   SharedRuntime::get_handle_wrong_method_stub());
1436     }
1437 
1438     if (is_in_use()) {
1439       // It's a true state change, so mark the method as decompiled.
1440       // Do it only for transition from alive.
1441       inc_decompile_count();
1442     }
1443 
1444     // If the state is becoming a zombie, signal to unregister the nmethod with
1445     // the heap.
1446     // This nmethod may have already been unloaded during a full GC.
1447     if ((state == zombie) && !is_unloaded()) {
1448       nmethod_needs_unregister = true;
1449     }
1450 
1451     // Must happen before state change. Otherwise we have a race condition in
1452     // nmethod::can_not_entrant_be_converted(). I.e., a method can immediately
1453     // transition its state from 'not_entrant' to 'zombie' without having to wait
1454     // for stack scanning.
1455     if (state == not_entrant) {
1456       mark_as_seen_on_stack();
1457       OrderAccess::storestore();
1458     }
1459 
1460     // Change state
1461     _state = state;
1462 
1463     // Log the transition once
1464     log_state_change();
1465 
1466     // Remove nmethod from method.
1467     // We need to check if both the _code and _from_compiled_code_entry_point
1468     // refer to this nmethod because there is a race in setting these two fields
1469     // in Method* as seen in bugid 4947125.
1470     // If the vep() points to the zombie nmethod, the memory for the nmethod
1471     // could be flushed and the compiler and vtable stubs could still call
1472     // through it.
1473     if (method() != NULL && (method()->code() == this ||
1474                              method()->from_compiled_entry() == verified_entry_point())) {
1475       HandleMark hm;
1476       method()->clear_code();
1477     }
1478   } // leave critical region under Patching_lock
1479 
1480   // When the nmethod becomes zombie it is no longer alive so the
1481   // dependencies must be flushed.  nmethods in the not_entrant
1482   // state will be flushed later when the transition to zombie
1483   // happens or they get unloaded.
1484   if (state == zombie) {
1485     {
1486       // Flushing dependecies must be done before any possible
1487       // safepoint can sneak in, otherwise the oops used by the
1488       // dependency logic could have become stale.
1489       MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
1490       if (nmethod_needs_unregister) {
1491         Universe::heap()->unregister_nmethod(this);
1492       }
1493       flush_dependencies(NULL);
1494     }
1495 
1496     // zombie only - if a JVMTI agent has enabled the CompiledMethodUnload
1497     // event and it hasn't already been reported for this nmethod then
1498     // report it now. The event may have been reported earilier if the GC
1499     // marked it for unloading). JvmtiDeferredEventQueue support means
1500     // we no longer go to a safepoint here.
1501     post_compiled_method_unload();
1502 
1503 #ifdef ASSERT
1504     // It's no longer safe to access the oops section since zombie
1505     // nmethods aren't scanned for GC.
1506     _oops_are_stale = true;
1507 #endif
1508      // the Method may be reclaimed by class unloading now that the
1509      // nmethod is in zombie state
1510     set_method(NULL);
1511   } else {
1512     assert(state == not_entrant, "other cases may need to be handled differently");
1513   }
1514 
1515   if (TraceCreateZombies) {
1516     tty->print_cr("nmethod <" INTPTR_FORMAT "> code made %s", this, (state == not_entrant) ? "not entrant" : "zombie");
1517   }
1518 
1519   NMethodSweeper::report_state_change(this);
1520   return true;
1521 }
1522 
1523 void nmethod::flush() {
1524   // Note that there are no valid oops in the nmethod anymore.
1525   assert(is_zombie() || (is_osr_method() && is_unloaded()), "must be a zombie method");
1526   assert(is_marked_for_reclamation() || (is_osr_method() && is_unloaded()), "must be marked for reclamation");
1527 
1528   assert (!is_locked_by_vm(), "locked methods shouldn't be flushed");
1529   assert_locked_or_safepoint(CodeCache_lock);
1530 
1531   // completely deallocate this method
1532   Events::log(JavaThread::current(), "flushing nmethod " INTPTR_FORMAT, this);
1533   if (PrintMethodFlushing) {
1534     tty->print_cr("*flushing nmethod %3d/" INTPTR_FORMAT ". Live blobs:" UINT32_FORMAT "/Free CodeCache:" SIZE_FORMAT "Kb",
1535         _compile_id, this, CodeCache::nof_blobs(), CodeCache::unallocated_capacity()/1024);
1536   }
1537 
1538   // We need to deallocate any ExceptionCache data.
1539   // Note that we do not need to grab the nmethod lock for this, it
1540   // better be thread safe if we're disposing of it!
1541   ExceptionCache* ec = exception_cache();
1542   set_exception_cache(NULL);
1543   while(ec != NULL) {
1544     ExceptionCache* next = ec->next();
1545     delete ec;
1546     ec = next;
1547   }
1548 
1549   if (on_scavenge_root_list()) {
1550     CodeCache::drop_scavenge_root_nmethod(this);
1551   }
1552 
1553 #ifdef SHARK
1554   ((SharkCompiler *) compiler())->free_compiled_method(insts_begin());
1555 #endif // SHARK
1556 
1557   ((CodeBlob*)(this))->flush();
1558 
1559   CodeCache::free(this);
1560 }
1561 
1562 
1563 //
1564 // Notify all classes this nmethod is dependent on that it is no
1565 // longer dependent. This should only be called in two situations.
1566 // First, when a nmethod transitions to a zombie all dependents need
1567 // to be clear.  Since zombification happens at a safepoint there's no
1568 // synchronization issues.  The second place is a little more tricky.
1569 // During phase 1 of mark sweep class unloading may happen and as a
1570 // result some nmethods may get unloaded.  In this case the flushing
1571 // of dependencies must happen during phase 1 since after GC any
1572 // dependencies in the unloaded nmethod won't be updated, so
1573 // traversing the dependency information in unsafe.  In that case this
1574 // function is called with a non-NULL argument and this function only
1575 // notifies instanceKlasses that are reachable
1576 
1577 void nmethod::flush_dependencies(BoolObjectClosure* is_alive) {
1578   assert_locked_or_safepoint(CodeCache_lock);
1579   assert(Universe::heap()->is_gc_active() == (is_alive != NULL),
1580   "is_alive is non-NULL if and only if we are called during GC");
1581   if (!has_flushed_dependencies()) {
1582     set_has_flushed_dependencies();
1583     for (Dependencies::DepStream deps(this); deps.next(); ) {
1584       Klass* klass = deps.context_type();
1585       if (klass == NULL)  continue;  // ignore things like evol_method
1586 
1587       // During GC the is_alive closure is non-NULL, and is used to
1588       // determine liveness of dependees that need to be updated.
1589       if (is_alive == NULL || klass->is_loader_alive(is_alive)) {
1590         InstanceKlass::cast(klass)->remove_dependent_nmethod(this);
1591       }
1592     }
1593   }
1594 }
1595 
1596 
1597 // If this oop is not live, the nmethod can be unloaded.
1598 bool nmethod::can_unload(BoolObjectClosure* is_alive, oop* root, bool unloading_occurred) {
1599   assert(root != NULL, "just checking");
1600   oop obj = *root;
1601   if (obj == NULL || is_alive->do_object_b(obj)) {
1602       return false;
1603   }
1604 
1605   // If ScavengeRootsInCode is true, an nmethod might be unloaded
1606   // simply because one of its constant oops has gone dead.
1607   // No actual classes need to be unloaded in order for this to occur.
1608   assert(unloading_occurred || ScavengeRootsInCode, "Inconsistency in unloading");
1609   make_unloaded(is_alive, obj);
1610   return true;
1611 }
1612 
1613 // ------------------------------------------------------------------
1614 // post_compiled_method_load_event
1615 // new method for install_code() path
1616 // Transfer information from compilation to jvmti
1617 void nmethod::post_compiled_method_load_event() {
1618 
1619   Method* moop = method();
1620   HOTSPOT_COMPILED_METHOD_LOAD(
1621       (char *) moop->klass_name()->bytes(),
1622       moop->klass_name()->utf8_length(),
1623       (char *) moop->name()->bytes(),
1624       moop->name()->utf8_length(),
1625       (char *) moop->signature()->bytes(),
1626       moop->signature()->utf8_length(),
1627       insts_begin(), insts_size());
1628 
1629   if (JvmtiExport::should_post_compiled_method_load() ||
1630       JvmtiExport::should_post_compiled_method_unload()) {
1631     get_and_cache_jmethod_id();
1632   }
1633 
1634   if (JvmtiExport::should_post_compiled_method_load()) {
1635     // Let the Service thread (which is a real Java thread) post the event
1636     MutexLockerEx ml(Service_lock, Mutex::_no_safepoint_check_flag);
1637     JvmtiDeferredEventQueue::enqueue(
1638       JvmtiDeferredEvent::compiled_method_load_event(this));
1639   }
1640 }
1641 
1642 jmethodID nmethod::get_and_cache_jmethod_id() {
1643   if (_jmethod_id == NULL) {
1644     // Cache the jmethod_id since it can no longer be looked up once the
1645     // method itself has been marked for unloading.
1646     _jmethod_id = method()->jmethod_id();
1647   }
1648   return _jmethod_id;
1649 }
1650 
1651 void nmethod::post_compiled_method_unload() {
1652   if (unload_reported()) {
1653     // During unloading we transition to unloaded and then to zombie
1654     // and the unloading is reported during the first transition.
1655     return;
1656   }
1657 
1658   assert(_method != NULL && !is_unloaded(), "just checking");
1659   DTRACE_METHOD_UNLOAD_PROBE(method());
1660 
1661   // If a JVMTI agent has enabled the CompiledMethodUnload event then
1662   // post the event. Sometime later this nmethod will be made a zombie
1663   // by the sweeper but the Method* will not be valid at that point.
1664   // If the _jmethod_id is null then no load event was ever requested
1665   // so don't bother posting the unload.  The main reason for this is
1666   // that the jmethodID is a weak reference to the Method* so if
1667   // it's being unloaded there's no way to look it up since the weak
1668   // ref will have been cleared.
1669   if (_jmethod_id != NULL && JvmtiExport::should_post_compiled_method_unload()) {
1670     assert(!unload_reported(), "already unloaded");
1671     JvmtiDeferredEvent event =
1672       JvmtiDeferredEvent::compiled_method_unload_event(this,
1673           _jmethod_id, insts_begin());
1674     if (SafepointSynchronize::is_at_safepoint()) {
1675       // Don't want to take the queueing lock. Add it as pending and
1676       // it will get enqueued later.
1677       JvmtiDeferredEventQueue::add_pending_event(event);
1678     } else {
1679       MutexLockerEx ml(Service_lock, Mutex::_no_safepoint_check_flag);
1680       JvmtiDeferredEventQueue::enqueue(event);
1681     }
1682   }
1683 
1684   // The JVMTI CompiledMethodUnload event can be enabled or disabled at
1685   // any time. As the nmethod is being unloaded now we mark it has
1686   // having the unload event reported - this will ensure that we don't
1687   // attempt to report the event in the unlikely scenario where the
1688   // event is enabled at the time the nmethod is made a zombie.
1689   set_unload_reported();
1690 }
1691 
1692 void static clean_ic_if_metadata_is_dead(CompiledIC *ic, BoolObjectClosure *is_alive) {
1693   if (ic->is_icholder_call()) {
1694     // The only exception is compiledICHolder oops which may
1695     // yet be marked below. (We check this further below).
1696     CompiledICHolder* cichk_oop = ic->cached_icholder();
1697     if (cichk_oop->holder_method()->method_holder()->is_loader_alive(is_alive) &&
1698         cichk_oop->holder_klass()->is_loader_alive(is_alive)) {
1699       return;
1700     }
1701   } else {
1702     Metadata* ic_oop = ic->cached_metadata();
1703     if (ic_oop != NULL) {
1704       if (ic_oop->is_klass()) {
1705         if (((Klass*)ic_oop)->is_loader_alive(is_alive)) {
1706           return;
1707         }
1708       } else if (ic_oop->is_method()) {
1709         if (((Method*)ic_oop)->method_holder()->is_loader_alive(is_alive)) {
1710           return;
1711         }
1712       } else {
1713         ShouldNotReachHere();
1714       }
1715     }
1716   }
1717 
1718   ic->set_to_clean();
1719 }
1720 
1721 // This is called at the end of the strong tracing/marking phase of a
1722 // GC to unload an nmethod if it contains otherwise unreachable
1723 // oops.
1724 
1725 void nmethod::do_unloading(BoolObjectClosure* is_alive, bool unloading_occurred) {
1726   // Make sure the oop's ready to receive visitors
1727   assert(!is_zombie() && !is_unloaded(),
1728          "should not call follow on zombie or unloaded nmethod");
1729 
1730   // If the method is not entrant then a JMP is plastered over the
1731   // first few bytes.  If an oop in the old code was there, that oop
1732   // should not get GC'd.  Skip the first few bytes of oops on
1733   // not-entrant methods.
1734   address low_boundary = verified_entry_point();
1735   if (is_not_entrant()) {
1736     low_boundary += NativeJump::instruction_size;
1737     // %%% Note:  On SPARC we patch only a 4-byte trap, not a full NativeJump.
1738     // (See comment above.)
1739   }
1740 
1741   // The RedefineClasses() API can cause the class unloading invariant
1742   // to no longer be true. See jvmtiExport.hpp for details.
1743   // Also, leave a debugging breadcrumb in local flag.
1744   bool a_class_was_redefined = JvmtiExport::has_redefined_a_class();
1745   if (a_class_was_redefined) {
1746     // This set of the unloading_occurred flag is done before the
1747     // call to post_compiled_method_unload() so that the unloading
1748     // of this nmethod is reported.
1749     unloading_occurred = true;
1750   }
1751 
1752   // Exception cache
1753   clean_exception_cache(is_alive);
1754 
1755   // If class unloading occurred we first iterate over all inline caches and
1756   // clear ICs where the cached oop is referring to an unloaded klass or method.
1757   // The remaining live cached oops will be traversed in the relocInfo::oop_type
1758   // iteration below.
1759   if (unloading_occurred) {
1760     RelocIterator iter(this, low_boundary);
1761     while(iter.next()) {
1762       if (iter.type() == relocInfo::virtual_call_type) {
1763         CompiledIC *ic = CompiledIC_at(&iter);
1764         clean_ic_if_metadata_is_dead(ic, is_alive);
1765       }
1766     }
1767   }
1768 
1769   // Compiled code
1770   {
1771   RelocIterator iter(this, low_boundary);
1772   while (iter.next()) {
1773     if (iter.type() == relocInfo::oop_type) {
1774       oop_Relocation* r = iter.oop_reloc();
1775       // In this loop, we must only traverse those oops directly embedded in
1776       // the code.  Other oops (oop_index>0) are seen as part of scopes_oops.
1777       assert(1 == (r->oop_is_immediate()) +
1778                   (r->oop_addr() >= oops_begin() && r->oop_addr() < oops_end()),
1779              "oop must be found in exactly one place");
1780       if (r->oop_is_immediate() && r->oop_value() != NULL) {
1781         if (can_unload(is_alive, r->oop_addr(), unloading_occurred)) {
1782           return;
1783         }
1784       }
1785     }
1786   }
1787   }
1788 
1789 
1790   // Scopes
1791   for (oop* p = oops_begin(); p < oops_end(); p++) {
1792     if (*p == Universe::non_oop_word())  continue;  // skip non-oops
1793     if (can_unload(is_alive, p, unloading_occurred)) {
1794       return;
1795     }
1796   }
1797 
1798   // Ensure that all metadata is still alive
1799   verify_metadata_loaders(low_boundary, is_alive);
1800 }
1801 
1802 template <class CompiledICorStaticCall>
1803 static bool clean_if_nmethod_is_unloaded(CompiledICorStaticCall *ic, address addr, BoolObjectClosure *is_alive, nmethod* from) {
1804   // Ok, to lookup references to zombies here
1805   CodeBlob *cb = CodeCache::find_blob_unsafe(addr);
1806   if (cb != NULL && cb->is_nmethod()) {
1807     nmethod* nm = (nmethod*)cb;
1808 
1809     if (nm->unloading_clock() != nmethod::global_unloading_clock()) {
1810       // The nmethod has not been processed yet.
1811       return true;
1812     }
1813 
1814     // Clean inline caches pointing to both zombie and not_entrant methods
1815     if (!nm->is_in_use() || (nm->method()->code() != nm)) {
1816       ic->set_to_clean();
1817       assert(ic->is_clean(), err_msg("nmethod " PTR_FORMAT "not clean %s", from, from->method()->name_and_sig_as_C_string()));
1818     }
1819   }
1820 
1821   return false;
1822 }
1823 
1824 static bool clean_if_nmethod_is_unloaded(CompiledIC *ic, BoolObjectClosure *is_alive, nmethod* from) {
1825   return clean_if_nmethod_is_unloaded(ic, ic->ic_destination(), is_alive, from);
1826 }
1827 
1828 static bool clean_if_nmethod_is_unloaded(CompiledStaticCall *csc, BoolObjectClosure *is_alive, nmethod* from) {
1829   return clean_if_nmethod_is_unloaded(csc, csc->destination(), is_alive, from);
1830 }
1831 
1832 bool nmethod::do_unloading_parallel(BoolObjectClosure* is_alive, bool unloading_occurred) {
1833   ResourceMark rm;
1834 
1835   // Make sure the oop's ready to receive visitors
1836   assert(!is_zombie() && !is_unloaded(),
1837          "should not call follow on zombie or unloaded nmethod");
1838 
1839   // If the method is not entrant then a JMP is plastered over the
1840   // first few bytes.  If an oop in the old code was there, that oop
1841   // should not get GC'd.  Skip the first few bytes of oops on
1842   // not-entrant methods.
1843   address low_boundary = verified_entry_point();
1844   if (is_not_entrant()) {
1845     low_boundary += NativeJump::instruction_size;
1846     // %%% Note:  On SPARC we patch only a 4-byte trap, not a full NativeJump.
1847     // (See comment above.)
1848   }
1849 
1850   // The RedefineClasses() API can cause the class unloading invariant
1851   // to no longer be true. See jvmtiExport.hpp for details.
1852   // Also, leave a debugging breadcrumb in local flag.
1853   bool a_class_was_redefined = JvmtiExport::has_redefined_a_class();
1854   if (a_class_was_redefined) {
1855     // This set of the unloading_occurred flag is done before the
1856     // call to post_compiled_method_unload() so that the unloading
1857     // of this nmethod is reported.
1858     unloading_occurred = true;
1859   }
1860 
1861   // Exception cache
1862   clean_exception_cache(is_alive);
1863 
1864   bool is_unloaded = false;
1865   bool postponed = false;
1866 
1867   RelocIterator iter(this, low_boundary);
1868   while(iter.next()) {
1869 
1870     switch (iter.type()) {
1871 
1872     case relocInfo::virtual_call_type:
1873       if (unloading_occurred) {
1874         // If class unloading occurred we first iterate over all inline caches and
1875         // clear ICs where the cached oop is referring to an unloaded klass or method.
1876         clean_ic_if_metadata_is_dead(CompiledIC_at(&iter), is_alive);
1877       }
1878 
1879       postponed |= clean_if_nmethod_is_unloaded(CompiledIC_at(&iter), is_alive, this);
1880       break;
1881 
1882     case relocInfo::opt_virtual_call_type:
1883       postponed |= clean_if_nmethod_is_unloaded(CompiledIC_at(&iter), is_alive, this);
1884       break;
1885 
1886     case relocInfo::static_call_type:
1887       postponed |= clean_if_nmethod_is_unloaded(compiledStaticCall_at(iter.reloc()), is_alive, this);
1888       break;
1889 
1890     case relocInfo::oop_type:
1891       if (!is_unloaded) {
1892         // Unload check
1893         oop_Relocation* r = iter.oop_reloc();
1894         // Traverse those oops directly embedded in the code.
1895         // Other oops (oop_index>0) are seen as part of scopes_oops.
1896         assert(1 == (r->oop_is_immediate()) +
1897                   (r->oop_addr() >= oops_begin() && r->oop_addr() < oops_end()),
1898               "oop must be found in exactly one place");
1899         if (r->oop_is_immediate() && r->oop_value() != NULL) {
1900           if (can_unload(is_alive, r->oop_addr(), unloading_occurred)) {
1901             is_unloaded = true;
1902           }
1903         }
1904       }
1905       break;
1906 
1907     }
1908   }
1909 
1910   if (is_unloaded) {
1911     return postponed;
1912   }
1913 
1914   // Scopes
1915   for (oop* p = oops_begin(); p < oops_end(); p++) {
1916     if (*p == Universe::non_oop_word())  continue;  // skip non-oops
1917     if (can_unload(is_alive, p, unloading_occurred)) {
1918       is_unloaded = true;
1919       break;
1920     }
1921   }
1922 
1923   if (is_unloaded) {
1924     return postponed;
1925   }
1926 
1927   // Ensure that all metadata is still alive
1928   verify_metadata_loaders(low_boundary, is_alive);
1929 
1930   return postponed;
1931 }
1932 
1933 void nmethod::do_unloading_parallel_postponed(BoolObjectClosure* is_alive, bool unloading_occurred) {
1934   ResourceMark rm;
1935 
1936   // Make sure the oop's ready to receive visitors
1937   assert(!is_zombie(),
1938          "should not call follow on zombie nmethod");
1939 
1940   // If the method is not entrant then a JMP is plastered over the
1941   // first few bytes.  If an oop in the old code was there, that oop
1942   // should not get GC'd.  Skip the first few bytes of oops on
1943   // not-entrant methods.
1944   address low_boundary = verified_entry_point();
1945   if (is_not_entrant()) {
1946     low_boundary += NativeJump::instruction_size;
1947     // %%% Note:  On SPARC we patch only a 4-byte trap, not a full NativeJump.
1948     // (See comment above.)
1949   }
1950 
1951   RelocIterator iter(this, low_boundary);
1952   while(iter.next()) {
1953 
1954     switch (iter.type()) {
1955 
1956     case relocInfo::virtual_call_type:
1957       clean_if_nmethod_is_unloaded(CompiledIC_at(&iter), is_alive, this);
1958       break;
1959 
1960     case relocInfo::opt_virtual_call_type:
1961       clean_if_nmethod_is_unloaded(CompiledIC_at(&iter), is_alive, this);
1962       break;
1963 
1964     case relocInfo::static_call_type:
1965       clean_if_nmethod_is_unloaded(compiledStaticCall_at(iter.reloc()), is_alive, this);
1966       break;
1967     }
1968   }
1969 }
1970 
1971 #ifdef ASSERT
1972 
1973 class CheckClass : AllStatic {
1974   static BoolObjectClosure* _is_alive;
1975 
1976   // Check class_loader is alive for this bit of metadata.
1977   static void check_class(Metadata* md) {
1978     Klass* klass = NULL;
1979     if (md->is_klass()) {
1980       klass = ((Klass*)md);
1981     } else if (md->is_method()) {
1982       klass = ((Method*)md)->method_holder();
1983     } else if (md->is_methodData()) {
1984       klass = ((MethodData*)md)->method()->method_holder();
1985     } else {
1986       md->print();
1987       ShouldNotReachHere();
1988     }
1989     assert(klass->is_loader_alive(_is_alive), "must be alive");
1990   }
1991  public:
1992   static void do_check_class(BoolObjectClosure* is_alive, nmethod* nm) {
1993     assert(SafepointSynchronize::is_at_safepoint(), "this is only ok at safepoint");
1994     _is_alive = is_alive;
1995     nm->metadata_do(check_class);
1996   }
1997 };
1998 
1999 // This is called during a safepoint so can use static data
2000 BoolObjectClosure* CheckClass::_is_alive = NULL;
2001 #endif // ASSERT
2002 
2003 
2004 // Processing of oop references should have been sufficient to keep
2005 // all strong references alive.  Any weak references should have been
2006 // cleared as well.  Visit all the metadata and ensure that it's
2007 // really alive.
2008 void nmethod::verify_metadata_loaders(address low_boundary, BoolObjectClosure* is_alive) {
2009 #ifdef ASSERT
2010     RelocIterator iter(this, low_boundary);
2011     while (iter.next()) {
2012     // static_stub_Relocations may have dangling references to
2013     // Method*s so trim them out here.  Otherwise it looks like
2014     // compiled code is maintaining a link to dead metadata.
2015     address static_call_addr = NULL;
2016     if (iter.type() == relocInfo::opt_virtual_call_type) {
2017       CompiledIC* cic = CompiledIC_at(&iter);
2018       if (!cic->is_call_to_interpreted()) {
2019         static_call_addr = iter.addr();
2020       }
2021     } else if (iter.type() == relocInfo::static_call_type) {
2022       CompiledStaticCall* csc = compiledStaticCall_at(iter.reloc());
2023       if (!csc->is_call_to_interpreted()) {
2024         static_call_addr = iter.addr();
2025       }
2026     }
2027     if (static_call_addr != NULL) {
2028       RelocIterator sciter(this, low_boundary);
2029       while (sciter.next()) {
2030         if (sciter.type() == relocInfo::static_stub_type &&
2031             sciter.static_stub_reloc()->static_call() == static_call_addr) {
2032           sciter.static_stub_reloc()->clear_inline_cache();
2033         }
2034       }
2035     }
2036   }
2037   // Check that the metadata embedded in the nmethod is alive
2038   CheckClass::do_check_class(is_alive, this);
2039 #endif
2040 }
2041 
2042 
2043 // Iterate over metadata calling this function.   Used by RedefineClasses
2044 void nmethod::metadata_do(void f(Metadata*)) {
2045   address low_boundary = verified_entry_point();
2046   if (is_not_entrant()) {
2047     low_boundary += NativeJump::instruction_size;
2048     // %%% Note:  On SPARC we patch only a 4-byte trap, not a full NativeJump.
2049     // (See comment above.)
2050   }
2051   {
2052     // Visit all immediate references that are embedded in the instruction stream.
2053     RelocIterator iter(this, low_boundary);
2054     while (iter.next()) {
2055       if (iter.type() == relocInfo::metadata_type ) {
2056         metadata_Relocation* r = iter.metadata_reloc();
2057         // In this lmetadata, we must only follow those metadatas directly embedded in
2058         // the code.  Other metadatas (oop_index>0) are seen as part of
2059         // the metadata section below.
2060         assert(1 == (r->metadata_is_immediate()) +
2061                (r->metadata_addr() >= metadata_begin() && r->metadata_addr() < metadata_end()),
2062                "metadata must be found in exactly one place");
2063         if (r->metadata_is_immediate() && r->metadata_value() != NULL) {
2064           Metadata* md = r->metadata_value();
2065           if (md != _method) f(md);
2066         }
2067       } else if (iter.type() == relocInfo::virtual_call_type) {
2068         // Check compiledIC holders associated with this nmethod
2069         CompiledIC *ic = CompiledIC_at(&iter);
2070         if (ic->is_icholder_call()) {
2071           CompiledICHolder* cichk = ic->cached_icholder();
2072           f(cichk->holder_method());
2073           f(cichk->holder_klass());
2074         } else {
2075           Metadata* ic_oop = ic->cached_metadata();
2076           if (ic_oop != NULL) {
2077             f(ic_oop);
2078           }
2079         }
2080       }
2081     }
2082   }
2083 
2084   // Visit the metadata section
2085   for (Metadata** p = metadata_begin(); p < metadata_end(); p++) {
2086     if (*p == Universe::non_oop_word() || *p == NULL)  continue;  // skip non-oops
2087     Metadata* md = *p;
2088     f(md);
2089   }
2090 }
2091 
2092 void nmethod::oops_do(OopClosure* f, bool allow_zombie) {
2093   // make sure the oops ready to receive visitors
2094   assert(allow_zombie || !is_zombie(), "should not call follow on zombie nmethod");
2095   assert(!is_unloaded(), "should not call follow on unloaded nmethod");
2096 
2097   // If the method is not entrant or zombie then a JMP is plastered over the
2098   // first few bytes.  If an oop in the old code was there, that oop
2099   // should not get GC'd.  Skip the first few bytes of oops on
2100   // not-entrant methods.
2101   address low_boundary = verified_entry_point();
2102   if (is_not_entrant()) {
2103     low_boundary += NativeJump::instruction_size;
2104     // %%% Note:  On SPARC we patch only a 4-byte trap, not a full NativeJump.
2105     // (See comment above.)
2106   }
2107 
2108   RelocIterator iter(this, low_boundary);
2109 
2110   while (iter.next()) {
2111     if (iter.type() == relocInfo::oop_type ) {
2112       oop_Relocation* r = iter.oop_reloc();
2113       // In this loop, we must only follow those oops directly embedded in
2114       // the code.  Other oops (oop_index>0) are seen as part of scopes_oops.
2115       assert(1 == (r->oop_is_immediate()) +
2116                    (r->oop_addr() >= oops_begin() && r->oop_addr() < oops_end()),
2117              "oop must be found in exactly one place");
2118       if (r->oop_is_immediate() && r->oop_value() != NULL) {
2119         f->do_oop(r->oop_addr());
2120       }
2121     }
2122   }
2123 
2124   // Scopes
2125   // This includes oop constants not inlined in the code stream.
2126   for (oop* p = oops_begin(); p < oops_end(); p++) {
2127     if (*p == Universe::non_oop_word())  continue;  // skip non-oops
2128     f->do_oop(p);
2129   }
2130 }
2131 
2132 #define NMETHOD_SENTINEL ((nmethod*)badAddress)
2133 
2134 nmethod* volatile nmethod::_oops_do_mark_nmethods;
2135 
2136 // An nmethod is "marked" if its _mark_link is set non-null.
2137 // Even if it is the end of the linked list, it will have a non-null link value,
2138 // as long as it is on the list.
2139 // This code must be MP safe, because it is used from parallel GC passes.
2140 bool nmethod::test_set_oops_do_mark() {
2141   assert(nmethod::oops_do_marking_is_active(), "oops_do_marking_prologue must be called");
2142   nmethod* observed_mark_link = _oops_do_mark_link;
2143   if (observed_mark_link == NULL) {
2144     // Claim this nmethod for this thread to mark.
2145     observed_mark_link = (nmethod*)
2146       Atomic::cmpxchg_ptr(NMETHOD_SENTINEL, &_oops_do_mark_link, NULL);
2147     if (observed_mark_link == NULL) {
2148 
2149       // Atomically append this nmethod (now claimed) to the head of the list:
2150       nmethod* observed_mark_nmethods = _oops_do_mark_nmethods;
2151       for (;;) {
2152         nmethod* required_mark_nmethods = observed_mark_nmethods;
2153         _oops_do_mark_link = required_mark_nmethods;
2154         observed_mark_nmethods = (nmethod*)
2155           Atomic::cmpxchg_ptr(this, &_oops_do_mark_nmethods, required_mark_nmethods);
2156         if (observed_mark_nmethods == required_mark_nmethods)
2157           break;
2158       }
2159       // Mark was clear when we first saw this guy.
2160       NOT_PRODUCT(if (TraceScavenge)  print_on(tty, "oops_do, mark"));
2161       return false;
2162     }
2163   }
2164   // On fall through, another racing thread marked this nmethod before we did.
2165   return true;
2166 }
2167 
2168 void nmethod::oops_do_marking_prologue() {
2169   NOT_PRODUCT(if (TraceScavenge)  tty->print_cr("[oops_do_marking_prologue"));
2170   assert(_oops_do_mark_nmethods == NULL, "must not call oops_do_marking_prologue twice in a row");
2171   // We use cmpxchg_ptr instead of regular assignment here because the user
2172   // may fork a bunch of threads, and we need them all to see the same state.
2173   void* observed = Atomic::cmpxchg_ptr(NMETHOD_SENTINEL, &_oops_do_mark_nmethods, NULL);
2174   guarantee(observed == NULL, "no races in this sequential code");
2175 }
2176 
2177 void nmethod::oops_do_marking_epilogue() {
2178   assert(_oops_do_mark_nmethods != NULL, "must not call oops_do_marking_epilogue twice in a row");
2179   nmethod* cur = _oops_do_mark_nmethods;
2180   while (cur != NMETHOD_SENTINEL) {
2181     assert(cur != NULL, "not NULL-terminated");
2182     nmethod* next = cur->_oops_do_mark_link;
2183     cur->_oops_do_mark_link = NULL;
2184     cur->verify_oop_relocations();
2185     NOT_PRODUCT(if (TraceScavenge)  cur->print_on(tty, "oops_do, unmark"));
2186     cur = next;
2187   }
2188   void* required = _oops_do_mark_nmethods;
2189   void* observed = Atomic::cmpxchg_ptr(NULL, &_oops_do_mark_nmethods, required);
2190   guarantee(observed == required, "no races in this sequential code");
2191   NOT_PRODUCT(if (TraceScavenge)  tty->print_cr("oops_do_marking_epilogue]"));
2192 }
2193 
2194 class DetectScavengeRoot: public OopClosure {
2195   bool     _detected_scavenge_root;
2196 public:
2197   DetectScavengeRoot() : _detected_scavenge_root(false)
2198   { NOT_PRODUCT(_print_nm = NULL); }
2199   bool detected_scavenge_root() { return _detected_scavenge_root; }
2200   virtual void do_oop(oop* p) {
2201     if ((*p) != NULL && (*p)->is_scavengable()) {
2202       NOT_PRODUCT(maybe_print(p));
2203       _detected_scavenge_root = true;
2204     }
2205   }
2206   virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
2207 
2208 #ifndef PRODUCT
2209   nmethod* _print_nm;
2210   void maybe_print(oop* p) {
2211     if (_print_nm == NULL)  return;
2212     if (!_detected_scavenge_root)  _print_nm->print_on(tty, "new scavenge root");
2213     tty->print_cr(""PTR_FORMAT"[offset=%d] detected scavengable oop "PTR_FORMAT" (found at "PTR_FORMAT")",
2214                   _print_nm, (int)((intptr_t)p - (intptr_t)_print_nm),
2215                   (void *)(*p), (intptr_t)p);
2216     (*p)->print();
2217   }
2218 #endif //PRODUCT
2219 };
2220 
2221 bool nmethod::detect_scavenge_root_oops() {
2222   DetectScavengeRoot detect_scavenge_root;
2223   NOT_PRODUCT(if (TraceScavenge)  detect_scavenge_root._print_nm = this);
2224   oops_do(&detect_scavenge_root);
2225   return detect_scavenge_root.detected_scavenge_root();
2226 }
2227 
2228 // Method that knows how to preserve outgoing arguments at call. This method must be
2229 // called with a frame corresponding to a Java invoke
2230 void nmethod::preserve_callee_argument_oops(frame fr, const RegisterMap *reg_map, OopClosure* f) {
2231 #ifndef SHARK
2232   if (!method()->is_native()) {
2233     SimpleScopeDesc ssd(this, fr.pc());
2234     Bytecode_invoke call(ssd.method(), ssd.bci());
2235     bool has_receiver = call.has_receiver();
2236     bool has_appendix = call.has_appendix();
2237     Symbol* signature = call.signature();
2238     fr.oops_compiled_arguments_do(signature, has_receiver, has_appendix, reg_map, f);
2239   }
2240 #endif // !SHARK
2241 }
2242 
2243 
2244 oop nmethod::embeddedOop_at(u_char* p) {
2245   RelocIterator iter(this, p, p + 1);
2246   while (iter.next())
2247     if (iter.type() == relocInfo::oop_type) {
2248       return iter.oop_reloc()->oop_value();
2249     }
2250   return NULL;
2251 }
2252 
2253 
2254 inline bool includes(void* p, void* from, void* to) {
2255   return from <= p && p < to;
2256 }
2257 
2258 
2259 void nmethod::copy_scopes_pcs(PcDesc* pcs, int count) {
2260   assert(count >= 2, "must be sentinel values, at least");
2261 
2262 #ifdef ASSERT
2263   // must be sorted and unique; we do a binary search in find_pc_desc()
2264   int prev_offset = pcs[0].pc_offset();
2265   assert(prev_offset == PcDesc::lower_offset_limit,
2266          "must start with a sentinel");
2267   for (int i = 1; i < count; i++) {
2268     int this_offset = pcs[i].pc_offset();
2269     assert(this_offset > prev_offset, "offsets must be sorted");
2270     prev_offset = this_offset;
2271   }
2272   assert(prev_offset == PcDesc::upper_offset_limit,
2273          "must end with a sentinel");
2274 #endif //ASSERT
2275 
2276   // Search for MethodHandle invokes and tag the nmethod.
2277   for (int i = 0; i < count; i++) {
2278     if (pcs[i].is_method_handle_invoke()) {
2279       set_has_method_handle_invokes(true);
2280       break;
2281     }
2282   }
2283   assert(has_method_handle_invokes() == (_deoptimize_mh_offset != -1), "must have deopt mh handler");
2284 
2285   int size = count * sizeof(PcDesc);
2286   assert(scopes_pcs_size() >= size, "oob");
2287   memcpy(scopes_pcs_begin(), pcs, size);
2288 
2289   // Adjust the final sentinel downward.
2290   PcDesc* last_pc = &scopes_pcs_begin()[count-1];
2291   assert(last_pc->pc_offset() == PcDesc::upper_offset_limit, "sanity");
2292   last_pc->set_pc_offset(content_size() + 1);
2293   for (; last_pc + 1 < scopes_pcs_end(); last_pc += 1) {
2294     // Fill any rounding gaps with copies of the last record.
2295     last_pc[1] = last_pc[0];
2296   }
2297   // The following assert could fail if sizeof(PcDesc) is not
2298   // an integral multiple of oopSize (the rounding term).
2299   // If it fails, change the logic to always allocate a multiple
2300   // of sizeof(PcDesc), and fill unused words with copies of *last_pc.
2301   assert(last_pc + 1 == scopes_pcs_end(), "must match exactly");
2302 }
2303 
2304 void nmethod::copy_scopes_data(u_char* buffer, int size) {
2305   assert(scopes_data_size() >= size, "oob");
2306   memcpy(scopes_data_begin(), buffer, size);
2307 }
2308 
2309 
2310 #ifdef ASSERT
2311 static PcDesc* linear_search(nmethod* nm, int pc_offset, bool approximate) {
2312   PcDesc* lower = nm->scopes_pcs_begin();
2313   PcDesc* upper = nm->scopes_pcs_end();
2314   lower += 1; // exclude initial sentinel
2315   PcDesc* res = NULL;
2316   for (PcDesc* p = lower; p < upper; p++) {
2317     NOT_PRODUCT(--nmethod_stats.pc_desc_tests);  // don't count this call to match_desc
2318     if (match_desc(p, pc_offset, approximate)) {
2319       if (res == NULL)
2320         res = p;
2321       else
2322         res = (PcDesc*) badAddress;
2323     }
2324   }
2325   return res;
2326 }
2327 #endif
2328 
2329 
2330 // Finds a PcDesc with real-pc equal to "pc"
2331 PcDesc* nmethod::find_pc_desc_internal(address pc, bool approximate) {
2332   address base_address = code_begin();
2333   if ((pc < base_address) ||
2334       (pc - base_address) >= (ptrdiff_t) PcDesc::upper_offset_limit) {
2335     return NULL;  // PC is wildly out of range
2336   }
2337   int pc_offset = (int) (pc - base_address);
2338 
2339   // Check the PcDesc cache if it contains the desired PcDesc
2340   // (This as an almost 100% hit rate.)
2341   PcDesc* res = _pc_desc_cache.find_pc_desc(pc_offset, approximate);
2342   if (res != NULL) {
2343     assert(res == linear_search(this, pc_offset, approximate), "cache ok");
2344     return res;
2345   }
2346 
2347   // Fallback algorithm: quasi-linear search for the PcDesc
2348   // Find the last pc_offset less than the given offset.
2349   // The successor must be the required match, if there is a match at all.
2350   // (Use a fixed radix to avoid expensive affine pointer arithmetic.)
2351   PcDesc* lower = scopes_pcs_begin();
2352   PcDesc* upper = scopes_pcs_end();
2353   upper -= 1; // exclude final sentinel
2354   if (lower >= upper)  return NULL;  // native method; no PcDescs at all
2355 
2356 #define assert_LU_OK \
2357   /* invariant on lower..upper during the following search: */ \
2358   assert(lower->pc_offset() <  pc_offset, "sanity"); \
2359   assert(upper->pc_offset() >= pc_offset, "sanity")
2360   assert_LU_OK;
2361 
2362   // Use the last successful return as a split point.
2363   PcDesc* mid = _pc_desc_cache.last_pc_desc();
2364   NOT_PRODUCT(++nmethod_stats.pc_desc_searches);
2365   if (mid->pc_offset() < pc_offset) {
2366     lower = mid;
2367   } else {
2368     upper = mid;
2369   }
2370 
2371   // Take giant steps at first (4096, then 256, then 16, then 1)
2372   const int LOG2_RADIX = 4 /*smaller steps in debug mode:*/ debug_only(-1);
2373   const int RADIX = (1 << LOG2_RADIX);
2374   for (int step = (1 << (LOG2_RADIX*3)); step > 1; step >>= LOG2_RADIX) {
2375     while ((mid = lower + step) < upper) {
2376       assert_LU_OK;
2377       NOT_PRODUCT(++nmethod_stats.pc_desc_searches);
2378       if (mid->pc_offset() < pc_offset) {
2379         lower = mid;
2380       } else {
2381         upper = mid;
2382         break;
2383       }
2384     }
2385     assert_LU_OK;
2386   }
2387 
2388   // Sneak up on the value with a linear search of length ~16.
2389   while (true) {
2390     assert_LU_OK;
2391     mid = lower + 1;
2392     NOT_PRODUCT(++nmethod_stats.pc_desc_searches);
2393     if (mid->pc_offset() < pc_offset) {
2394       lower = mid;
2395     } else {
2396       upper = mid;
2397       break;
2398     }
2399   }
2400 #undef assert_LU_OK
2401 
2402   if (match_desc(upper, pc_offset, approximate)) {
2403     assert(upper == linear_search(this, pc_offset, approximate), "search ok");
2404     _pc_desc_cache.add_pc_desc(upper);
2405     return upper;
2406   } else {
2407     assert(NULL == linear_search(this, pc_offset, approximate), "search ok");
2408     return NULL;
2409   }
2410 }
2411 
2412 
2413 void nmethod::check_all_dependencies(DepChange& changes) {
2414   // Checked dependencies are allocated into this ResourceMark
2415   ResourceMark rm;
2416 
2417   // Turn off dependency tracing while actually testing dependencies.
2418   NOT_PRODUCT( FlagSetting fs(TraceDependencies, false) );
2419 
2420  typedef ResourceHashtable<DependencySignature, int, &DependencySignature::hash,
2421                            &DependencySignature::equals, 11027> DepTable;
2422 
2423  DepTable* table = new DepTable();
2424 
2425   // Iterate over live nmethods and check dependencies of all nmethods that are not
2426   // marked for deoptimization. A particular dependency is only checked once.
2427   for(nmethod* nm = CodeCache::alive_nmethod(CodeCache::first()); nm != NULL; nm = CodeCache::alive_nmethod(CodeCache::next(nm))) {
2428     if (!nm->is_marked_for_deoptimization()) {
2429       for (Dependencies::DepStream deps(nm); deps.next(); ) {
2430         // Construct abstraction of a dependency.
2431         DependencySignature* current_sig = new DependencySignature(deps);
2432 
2433         // Determine if dependency is already checked. table->put(...) returns
2434         // 'true' if the dependency is added (i.e., was not in the hashtable).
2435         if (table->put(*current_sig, 1)) {
2436           if (deps.check_dependency() != NULL) {
2437             // Dependency checking failed. Print out information about the failed
2438             // dependency and finally fail with an assert. We can fail here, since
2439             // dependency checking is never done in a product build.
2440             changes.print();
2441             nm->print();
2442             nm->print_dependencies();
2443             assert(false, "Should have been marked for deoptimization");
2444           }
2445         }
2446       }
2447     }
2448   }
2449 }
2450 
2451 bool nmethod::check_dependency_on(DepChange& changes) {
2452   // What has happened:
2453   // 1) a new class dependee has been added
2454   // 2) dependee and all its super classes have been marked
2455   bool found_check = false;  // set true if we are upset
2456   for (Dependencies::DepStream deps(this); deps.next(); ) {
2457     // Evaluate only relevant dependencies.
2458     if (deps.spot_check_dependency_at(changes) != NULL) {
2459       found_check = true;
2460       NOT_DEBUG(break);
2461     }
2462   }
2463   return found_check;
2464 }
2465 
2466 bool nmethod::is_evol_dependent_on(Klass* dependee) {
2467   InstanceKlass *dependee_ik = InstanceKlass::cast(dependee);
2468   Array<Method*>* dependee_methods = dependee_ik->methods();
2469   for (Dependencies::DepStream deps(this); deps.next(); ) {
2470     if (deps.type() == Dependencies::evol_method) {
2471       Method* method = deps.method_argument(0);
2472       for (int j = 0; j < dependee_methods->length(); j++) {
2473         if (dependee_methods->at(j) == method) {
2474           // RC_TRACE macro has an embedded ResourceMark
2475           RC_TRACE(0x01000000,
2476             ("Found evol dependency of nmethod %s.%s(%s) compile_id=%d on method %s.%s(%s)",
2477             _method->method_holder()->external_name(),
2478             _method->name()->as_C_string(),
2479             _method->signature()->as_C_string(), compile_id(),
2480             method->method_holder()->external_name(),
2481             method->name()->as_C_string(),
2482             method->signature()->as_C_string()));
2483           if (TraceDependencies || LogCompilation)
2484             deps.log_dependency(dependee);
2485           return true;
2486         }
2487       }
2488     }
2489   }
2490   return false;
2491 }
2492 
2493 // Called from mark_for_deoptimization, when dependee is invalidated.
2494 bool nmethod::is_dependent_on_method(Method* dependee) {
2495   for (Dependencies::DepStream deps(this); deps.next(); ) {
2496     if (deps.type() != Dependencies::evol_method)
2497       continue;
2498     Method* method = deps.method_argument(0);
2499     if (method == dependee) return true;
2500   }
2501   return false;
2502 }
2503 
2504 
2505 bool nmethod::is_patchable_at(address instr_addr) {
2506   assert(insts_contains(instr_addr), "wrong nmethod used");
2507   if (is_zombie()) {
2508     // a zombie may never be patched
2509     return false;
2510   }
2511   return true;
2512 }
2513 
2514 
2515 address nmethod::continuation_for_implicit_exception(address pc) {
2516   // Exception happened outside inline-cache check code => we are inside
2517   // an active nmethod => use cpc to determine a return address
2518   int exception_offset = pc - code_begin();
2519   int cont_offset = ImplicitExceptionTable(this).at( exception_offset );
2520 #ifdef ASSERT
2521   if (cont_offset == 0) {
2522     Thread* thread = ThreadLocalStorage::get_thread_slow();
2523     ResetNoHandleMark rnm; // Might be called from LEAF/QUICK ENTRY
2524     HandleMark hm(thread);
2525     ResourceMark rm(thread);
2526     CodeBlob* cb = CodeCache::find_blob(pc);
2527     assert(cb != NULL && cb == this, "");
2528     tty->print_cr("implicit exception happened at " INTPTR_FORMAT, pc);
2529     print();
2530     method()->print_codes();
2531     print_code();
2532     print_pcs();
2533   }
2534 #endif
2535   if (cont_offset == 0) {
2536     // Let the normal error handling report the exception
2537     return NULL;
2538   }
2539   return code_begin() + cont_offset;
2540 }
2541 
2542 
2543 
2544 void nmethod_init() {
2545   // make sure you didn't forget to adjust the filler fields
2546   assert(sizeof(nmethod) % oopSize == 0, "nmethod size must be multiple of a word");
2547 }
2548 
2549 
2550 //-------------------------------------------------------------------------------------------
2551 
2552 
2553 // QQQ might we make this work from a frame??
2554 nmethodLocker::nmethodLocker(address pc) {
2555   CodeBlob* cb = CodeCache::find_blob(pc);
2556   guarantee(cb != NULL && cb->is_nmethod(), "bad pc for a nmethod found");
2557   _nm = (nmethod*)cb;
2558   lock_nmethod(_nm);
2559 }
2560 
2561 // Only JvmtiDeferredEvent::compiled_method_unload_event()
2562 // should pass zombie_ok == true.
2563 void nmethodLocker::lock_nmethod(nmethod* nm, bool zombie_ok) {
2564   if (nm == NULL)  return;
2565   Atomic::inc(&nm->_lock_count);
2566   assert(zombie_ok || !nm->is_zombie(), "cannot lock a zombie method");
2567 }
2568 
2569 void nmethodLocker::unlock_nmethod(nmethod* nm) {
2570   if (nm == NULL)  return;
2571   Atomic::dec(&nm->_lock_count);
2572   assert(nm->_lock_count >= 0, "unmatched nmethod lock/unlock");
2573 }
2574 
2575 
2576 // -----------------------------------------------------------------------------
2577 // nmethod::get_deopt_original_pc
2578 //
2579 // Return the original PC for the given PC if:
2580 // (a) the given PC belongs to a nmethod and
2581 // (b) it is a deopt PC
2582 address nmethod::get_deopt_original_pc(const frame* fr) {
2583   if (fr->cb() == NULL)  return NULL;
2584 
2585   nmethod* nm = fr->cb()->as_nmethod_or_null();
2586   if (nm != NULL && nm->is_deopt_pc(fr->pc()))
2587     return nm->get_original_pc(fr);
2588 
2589   return NULL;
2590 }
2591 
2592 
2593 // -----------------------------------------------------------------------------
2594 // MethodHandle
2595 
2596 bool nmethod::is_method_handle_return(address return_pc) {
2597   if (!has_method_handle_invokes())  return false;
2598   PcDesc* pd = pc_desc_at(return_pc);
2599   if (pd == NULL)
2600     return false;
2601   return pd->is_method_handle_invoke();
2602 }
2603 
2604 
2605 // -----------------------------------------------------------------------------
2606 // Verification
2607 
2608 class VerifyOopsClosure: public OopClosure {
2609   nmethod* _nm;
2610   bool     _ok;
2611 public:
2612   VerifyOopsClosure(nmethod* nm) : _nm(nm), _ok(true) { }
2613   bool ok() { return _ok; }
2614   virtual void do_oop(oop* p) {
2615     if ((*p) == NULL || (*p)->is_oop())  return;
2616     if (_ok) {
2617       _nm->print_nmethod(true);
2618       _ok = false;
2619     }
2620     tty->print_cr("*** non-oop "PTR_FORMAT" found at "PTR_FORMAT" (offset %d)",
2621                   (void *)(*p), (intptr_t)p, (int)((intptr_t)p - (intptr_t)_nm));
2622   }
2623   virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
2624 };
2625 
2626 void nmethod::verify() {
2627 
2628   // Hmm. OSR methods can be deopted but not marked as zombie or not_entrant
2629   // seems odd.
2630 
2631   if( is_zombie() || is_not_entrant() )
2632     return;
2633 
2634   // Make sure all the entry points are correctly aligned for patching.
2635   NativeJump::check_verified_entry_alignment(entry_point(), verified_entry_point());
2636 
2637   // assert(method()->is_oop(), "must be valid");
2638 
2639   ResourceMark rm;
2640 
2641   if (!CodeCache::contains(this)) {
2642     fatal(err_msg("nmethod at " INTPTR_FORMAT " not in zone", this));
2643   }
2644 
2645   if(is_native_method() )
2646     return;
2647 
2648   nmethod* nm = CodeCache::find_nmethod(verified_entry_point());
2649   if (nm != this) {
2650     fatal(err_msg("findNMethod did not find this nmethod (" INTPTR_FORMAT ")",
2651                   this));
2652   }
2653 
2654   for (PcDesc* p = scopes_pcs_begin(); p < scopes_pcs_end(); p++) {
2655     if (! p->verify(this)) {
2656       tty->print_cr("\t\tin nmethod at " INTPTR_FORMAT " (pcs)", this);
2657     }
2658   }
2659 
2660   VerifyOopsClosure voc(this);
2661   oops_do(&voc);
2662   assert(voc.ok(), "embedded oops must be OK");
2663   verify_scavenge_root_oops();
2664 
2665   verify_scopes();
2666 }
2667 
2668 
2669 void nmethod::verify_interrupt_point(address call_site) {
2670   // Verify IC only when nmethod installation is finished.
2671   bool is_installed = (method()->code() == this) // nmethod is in state 'in_use' and installed
2672                       || !this->is_in_use();     // nmethod is installed, but not in 'in_use' state
2673   if (is_installed) {
2674     Thread *cur = Thread::current();
2675     if (CompiledIC_lock->owner() == cur ||
2676         ((cur->is_VM_thread() || cur->is_ConcurrentGC_thread()) &&
2677          SafepointSynchronize::is_at_safepoint())) {
2678       CompiledIC_at(this, call_site);
2679       CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops());
2680     } else {
2681       MutexLocker ml_verify (CompiledIC_lock);
2682       CompiledIC_at(this, call_site);
2683     }
2684   }
2685 
2686   PcDesc* pd = pc_desc_at(nativeCall_at(call_site)->return_address());
2687   assert(pd != NULL, "PcDesc must exist");
2688   for (ScopeDesc* sd = new ScopeDesc(this, pd->scope_decode_offset(),
2689                                      pd->obj_decode_offset(), pd->should_reexecute(),
2690                                      pd->return_oop());
2691        !sd->is_top(); sd = sd->sender()) {
2692     sd->verify();
2693   }
2694 }
2695 
2696 void nmethod::verify_scopes() {
2697   if( !method() ) return;       // Runtime stubs have no scope
2698   if (method()->is_native()) return; // Ignore stub methods.
2699   // iterate through all interrupt point
2700   // and verify the debug information is valid.
2701   RelocIterator iter((nmethod*)this);
2702   while (iter.next()) {
2703     address stub = NULL;
2704     switch (iter.type()) {
2705       case relocInfo::virtual_call_type:
2706         verify_interrupt_point(iter.addr());
2707         break;
2708       case relocInfo::opt_virtual_call_type:
2709         stub = iter.opt_virtual_call_reloc()->static_stub();
2710         verify_interrupt_point(iter.addr());
2711         break;
2712       case relocInfo::static_call_type:
2713         stub = iter.static_call_reloc()->static_stub();
2714         //verify_interrupt_point(iter.addr());
2715         break;
2716       case relocInfo::runtime_call_type:
2717         address destination = iter.reloc()->value();
2718         // Right now there is no way to find out which entries support
2719         // an interrupt point.  It would be nice if we had this
2720         // information in a table.
2721         break;
2722     }
2723     assert(stub == NULL || stub_contains(stub), "static call stub outside stub section");
2724   }
2725 }
2726 
2727 
2728 // -----------------------------------------------------------------------------
2729 // Non-product code
2730 #ifndef PRODUCT
2731 
2732 class DebugScavengeRoot: public OopClosure {
2733   nmethod* _nm;
2734   bool     _ok;
2735 public:
2736   DebugScavengeRoot(nmethod* nm) : _nm(nm), _ok(true) { }
2737   bool ok() { return _ok; }
2738   virtual void do_oop(oop* p) {
2739     if ((*p) == NULL || !(*p)->is_scavengable())  return;
2740     if (_ok) {
2741       _nm->print_nmethod(true);
2742       _ok = false;
2743     }
2744     tty->print_cr("*** scavengable oop "PTR_FORMAT" found at "PTR_FORMAT" (offset %d)",
2745                   (void *)(*p), (intptr_t)p, (int)((intptr_t)p - (intptr_t)_nm));
2746     (*p)->print();
2747   }
2748   virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
2749 };
2750 
2751 void nmethod::verify_scavenge_root_oops() {
2752   if (UseG1GC) {
2753     return;
2754   }
2755 
2756   if (!on_scavenge_root_list()) {
2757     // Actually look inside, to verify the claim that it's clean.
2758     DebugScavengeRoot debug_scavenge_root(this);
2759     oops_do(&debug_scavenge_root);
2760     if (!debug_scavenge_root.ok())
2761       fatal("found an unadvertised bad scavengable oop in the code cache");
2762   }
2763   assert(scavenge_root_not_marked(), "");
2764 }
2765 
2766 #endif // PRODUCT
2767 
2768 // Printing operations
2769 
2770 void nmethod::print() const {
2771   ResourceMark rm;
2772   ttyLocker ttyl;   // keep the following output all in one block
2773 
2774   tty->print("Compiled method ");
2775 
2776   if (is_compiled_by_c1()) {
2777     tty->print("(c1) ");
2778   } else if (is_compiled_by_c2()) {
2779     tty->print("(c2) ");
2780   } else if (is_compiled_by_shark()) {
2781     tty->print("(shark) ");
2782   } else {
2783     tty->print("(nm) ");
2784   }
2785 
2786   print_on(tty, NULL);
2787 
2788   if (WizardMode) {
2789     tty->print("((nmethod*) "INTPTR_FORMAT ") ", this);
2790     tty->print(" for method " INTPTR_FORMAT , (address)method());
2791     tty->print(" { ");
2792     if (is_in_use())      tty->print("in_use ");
2793     if (is_not_entrant()) tty->print("not_entrant ");
2794     if (is_zombie())      tty->print("zombie ");
2795     if (is_unloaded())    tty->print("unloaded ");
2796     if (on_scavenge_root_list())  tty->print("scavenge_root ");
2797     tty->print_cr("}:");
2798   }
2799   if (size              () > 0) tty->print_cr(" total in heap  [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2800                                               (address)this,
2801                                               (address)this + size(),
2802                                               size());
2803   if (relocation_size   () > 0) tty->print_cr(" relocation     [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2804                                               relocation_begin(),
2805                                               relocation_end(),
2806                                               relocation_size());
2807   if (consts_size       () > 0) tty->print_cr(" constants      [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2808                                               consts_begin(),
2809                                               consts_end(),
2810                                               consts_size());
2811   if (insts_size        () > 0) tty->print_cr(" main code      [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2812                                               insts_begin(),
2813                                               insts_end(),
2814                                               insts_size());
2815   if (stub_size         () > 0) tty->print_cr(" stub code      [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2816                                               stub_begin(),
2817                                               stub_end(),
2818                                               stub_size());
2819   if (oops_size         () > 0) tty->print_cr(" oops           [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2820                                               oops_begin(),
2821                                               oops_end(),
2822                                               oops_size());
2823   if (metadata_size      () > 0) tty->print_cr(" metadata       [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2824                                               metadata_begin(),
2825                                               metadata_end(),
2826                                               metadata_size());
2827   if (scopes_data_size  () > 0) tty->print_cr(" scopes data    [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2828                                               scopes_data_begin(),
2829                                               scopes_data_end(),
2830                                               scopes_data_size());
2831   if (scopes_pcs_size   () > 0) tty->print_cr(" scopes pcs     [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2832                                               scopes_pcs_begin(),
2833                                               scopes_pcs_end(),
2834                                               scopes_pcs_size());
2835   if (dependencies_size () > 0) tty->print_cr(" dependencies   [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2836                                               dependencies_begin(),
2837                                               dependencies_end(),
2838                                               dependencies_size());
2839   if (handler_table_size() > 0) tty->print_cr(" handler table  [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2840                                               handler_table_begin(),
2841                                               handler_table_end(),
2842                                               handler_table_size());
2843   if (nul_chk_table_size() > 0) tty->print_cr(" nul chk table  [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2844                                               nul_chk_table_begin(),
2845                                               nul_chk_table_end(),
2846                                               nul_chk_table_size());
2847 }
2848 
2849 void nmethod::print_code() {
2850   HandleMark hm;
2851   ResourceMark m;
2852   Disassembler::decode(this);
2853 }
2854 
2855 
2856 #ifndef PRODUCT
2857 
2858 void nmethod::print_scopes() {
2859   // Find the first pc desc for all scopes in the code and print it.
2860   ResourceMark rm;
2861   for (PcDesc* p = scopes_pcs_begin(); p < scopes_pcs_end(); p++) {
2862     if (p->scope_decode_offset() == DebugInformationRecorder::serialized_null)
2863       continue;
2864 
2865     ScopeDesc* sd = scope_desc_at(p->real_pc(this));
2866     sd->print_on(tty, p);
2867   }
2868 }
2869 
2870 void nmethod::print_dependencies() {
2871   ResourceMark rm;
2872   ttyLocker ttyl;   // keep the following output all in one block
2873   tty->print_cr("Dependencies:");
2874   for (Dependencies::DepStream deps(this); deps.next(); ) {
2875     deps.print_dependency();
2876     Klass* ctxk = deps.context_type();
2877     if (ctxk != NULL) {
2878       if (ctxk->oop_is_instance() && ((InstanceKlass*)ctxk)->is_dependent_nmethod(this)) {
2879         tty->print_cr("   [nmethod<=klass]%s", ctxk->external_name());
2880       }
2881     }
2882     deps.log_dependency();  // put it into the xml log also
2883   }
2884 }
2885 
2886 
2887 void nmethod::print_relocations() {
2888   ResourceMark m;       // in case methods get printed via the debugger
2889   tty->print_cr("relocations:");
2890   RelocIterator iter(this);
2891   iter.print();
2892   if (UseRelocIndex) {
2893     jint* index_end   = (jint*)relocation_end() - 1;
2894     jint  index_size  = *index_end;
2895     jint* index_start = (jint*)( (address)index_end - index_size );
2896     tty->print_cr("    index @" INTPTR_FORMAT ": index_size=%d", index_start, index_size);
2897     if (index_size > 0) {
2898       jint* ip;
2899       for (ip = index_start; ip+2 <= index_end; ip += 2)
2900         tty->print_cr("  (%d %d) addr=" INTPTR_FORMAT " @" INTPTR_FORMAT,
2901                       ip[0],
2902                       ip[1],
2903                       header_end()+ip[0],
2904                       relocation_begin()-1+ip[1]);
2905       for (; ip < index_end; ip++)
2906         tty->print_cr("  (%d ?)", ip[0]);
2907       tty->print_cr("          @" INTPTR_FORMAT ": index_size=%d", ip, *ip);
2908       ip++;
2909       tty->print_cr("reloc_end @" INTPTR_FORMAT ":", ip);
2910     }
2911   }
2912 }
2913 
2914 
2915 void nmethod::print_pcs() {
2916   ResourceMark m;       // in case methods get printed via debugger
2917   tty->print_cr("pc-bytecode offsets:");
2918   for (PcDesc* p = scopes_pcs_begin(); p < scopes_pcs_end(); p++) {
2919     p->print(this);
2920   }
2921 }
2922 
2923 #endif // PRODUCT
2924 
2925 const char* nmethod::reloc_string_for(u_char* begin, u_char* end) {
2926   RelocIterator iter(this, begin, end);
2927   bool have_one = false;
2928   while (iter.next()) {
2929     have_one = true;
2930     switch (iter.type()) {
2931         case relocInfo::none:                  return "no_reloc";
2932         case relocInfo::oop_type: {
2933           stringStream st;
2934           oop_Relocation* r = iter.oop_reloc();
2935           oop obj = r->oop_value();
2936           st.print("oop(");
2937           if (obj == NULL) st.print("NULL");
2938           else obj->print_value_on(&st);
2939           st.print(")");
2940           return st.as_string();
2941         }
2942         case relocInfo::metadata_type: {
2943           stringStream st;
2944           metadata_Relocation* r = iter.metadata_reloc();
2945           Metadata* obj = r->metadata_value();
2946           st.print("metadata(");
2947           if (obj == NULL) st.print("NULL");
2948           else obj->print_value_on(&st);
2949           st.print(")");
2950           return st.as_string();
2951         }
2952         case relocInfo::virtual_call_type:     return "virtual_call";
2953         case relocInfo::opt_virtual_call_type: return "optimized virtual_call";
2954         case relocInfo::static_call_type:      return "static_call";
2955         case relocInfo::static_stub_type:      return "static_stub";
2956         case relocInfo::runtime_call_type:     return "runtime_call";
2957         case relocInfo::external_word_type:    return "external_word";
2958         case relocInfo::internal_word_type:    return "internal_word";
2959         case relocInfo::section_word_type:     return "section_word";
2960         case relocInfo::poll_type:             return "poll";
2961         case relocInfo::poll_return_type:      return "poll_return";
2962         case relocInfo::type_mask:             return "type_bit_mask";
2963     }
2964   }
2965   return have_one ? "other" : NULL;
2966 }
2967 
2968 // Return a the last scope in (begin..end]
2969 ScopeDesc* nmethod::scope_desc_in(address begin, address end) {
2970   PcDesc* p = pc_desc_near(begin+1);
2971   if (p != NULL && p->real_pc(this) <= end) {
2972     return new ScopeDesc(this, p->scope_decode_offset(),
2973                          p->obj_decode_offset(), p->should_reexecute(),
2974                          p->return_oop());
2975   }
2976   return NULL;
2977 }
2978 
2979 void nmethod::print_nmethod_labels(outputStream* stream, address block_begin) const {
2980   if (block_begin == entry_point())             stream->print_cr("[Entry Point]");
2981   if (block_begin == verified_entry_point())    stream->print_cr("[Verified Entry Point]");
2982   if (block_begin == exception_begin())         stream->print_cr("[Exception Handler]");
2983   if (block_begin == stub_begin())              stream->print_cr("[Stub Code]");
2984   if (block_begin == deopt_handler_begin())     stream->print_cr("[Deopt Handler Code]");
2985 
2986   if (has_method_handle_invokes())
2987     if (block_begin == deopt_mh_handler_begin())  stream->print_cr("[Deopt MH Handler Code]");
2988 
2989   if (block_begin == consts_begin())            stream->print_cr("[Constants]");
2990 
2991   if (block_begin == entry_point()) {
2992     methodHandle m = method();
2993     if (m.not_null()) {
2994       stream->print("  # ");
2995       m->print_value_on(stream);
2996       stream->cr();
2997     }
2998     if (m.not_null() && !is_osr_method()) {
2999       ResourceMark rm;
3000       int sizeargs = m->size_of_parameters();
3001       BasicType* sig_bt = NEW_RESOURCE_ARRAY(BasicType, sizeargs);
3002       VMRegPair* regs   = NEW_RESOURCE_ARRAY(VMRegPair, sizeargs);
3003       {
3004         int sig_index = 0;
3005         if (!m->is_static())
3006           sig_bt[sig_index++] = T_OBJECT; // 'this'
3007         for (SignatureStream ss(m->signature()); !ss.at_return_type(); ss.next()) {
3008           BasicType t = ss.type();
3009           sig_bt[sig_index++] = t;
3010           if (type2size[t] == 2) {
3011             sig_bt[sig_index++] = T_VOID;
3012           } else {
3013             assert(type2size[t] == 1, "size is 1 or 2");
3014           }
3015         }
3016         assert(sig_index == sizeargs, "");
3017       }
3018       const char* spname = "sp"; // make arch-specific?
3019       intptr_t out_preserve = SharedRuntime::java_calling_convention(sig_bt, regs, sizeargs, false);
3020       int stack_slot_offset = this->frame_size() * wordSize;
3021       int tab1 = 14, tab2 = 24;
3022       int sig_index = 0;
3023       int arg_index = (m->is_static() ? 0 : -1);
3024       bool did_old_sp = false;
3025       for (SignatureStream ss(m->signature()); !ss.at_return_type(); ) {
3026         bool at_this = (arg_index == -1);
3027         bool at_old_sp = false;
3028         BasicType t = (at_this ? T_OBJECT : ss.type());
3029         assert(t == sig_bt[sig_index], "sigs in sync");
3030         if (at_this)
3031           stream->print("  # this: ");
3032         else
3033           stream->print("  # parm%d: ", arg_index);
3034         stream->move_to(tab1);
3035         VMReg fst = regs[sig_index].first();
3036         VMReg snd = regs[sig_index].second();
3037         if (fst->is_reg()) {
3038           stream->print("%s", fst->name());
3039           if (snd->is_valid())  {
3040             stream->print(":%s", snd->name());
3041           }
3042         } else if (fst->is_stack()) {
3043           int offset = fst->reg2stack() * VMRegImpl::stack_slot_size + stack_slot_offset;
3044           if (offset == stack_slot_offset)  at_old_sp = true;
3045           stream->print("[%s+0x%x]", spname, offset);
3046         } else {
3047           stream->print("reg%d:%d??", (int)(intptr_t)fst, (int)(intptr_t)snd);
3048         }
3049         stream->print(" ");
3050         stream->move_to(tab2);
3051         stream->print("= ");
3052         if (at_this) {
3053           m->method_holder()->print_value_on(stream);
3054         } else {
3055           bool did_name = false;
3056           if (!at_this && ss.is_object()) {
3057             Symbol* name = ss.as_symbol_or_null();
3058             if (name != NULL) {
3059               name->print_value_on(stream);
3060               did_name = true;
3061             }
3062           }
3063           if (!did_name)
3064             stream->print("%s", type2name(t));
3065         }
3066         if (at_old_sp) {
3067           stream->print("  (%s of caller)", spname);
3068           did_old_sp = true;
3069         }
3070         stream->cr();
3071         sig_index += type2size[t];
3072         arg_index += 1;
3073         if (!at_this)  ss.next();
3074       }
3075       if (!did_old_sp) {
3076         stream->print("  # ");
3077         stream->move_to(tab1);
3078         stream->print("[%s+0x%x]", spname, stack_slot_offset);
3079         stream->print("  (%s of caller)", spname);
3080         stream->cr();
3081       }
3082     }
3083   }
3084 }
3085 
3086 void nmethod::print_code_comment_on(outputStream* st, int column, u_char* begin, u_char* end) {
3087   // First, find an oopmap in (begin, end].
3088   // We use the odd half-closed interval so that oop maps and scope descs
3089   // which are tied to the byte after a call are printed with the call itself.
3090   address base = code_begin();
3091   OopMapSet* oms = oop_maps();
3092   if (oms != NULL) {
3093     for (int i = 0, imax = oms->size(); i < imax; i++) {
3094       OopMap* om = oms->at(i);
3095       address pc = base + om->offset();
3096       if (pc > begin) {
3097         if (pc <= end) {
3098           st->move_to(column);
3099           st->print("; ");
3100           om->print_on(st);
3101         }
3102         break;
3103       }
3104     }
3105   }
3106 
3107   // Print any debug info present at this pc.
3108   ScopeDesc* sd  = scope_desc_in(begin, end);
3109   if (sd != NULL) {
3110     st->move_to(column);
3111     if (sd->bci() == SynchronizationEntryBCI) {
3112       st->print(";*synchronization entry");
3113     } else {
3114       if (sd->method() == NULL) {
3115         st->print("method is NULL");
3116       } else if (sd->method()->is_native()) {
3117         st->print("method is native");
3118       } else {
3119         Bytecodes::Code bc = sd->method()->java_code_at(sd->bci());
3120         st->print(";*%s", Bytecodes::name(bc));
3121         switch (bc) {
3122         case Bytecodes::_invokevirtual:
3123         case Bytecodes::_invokespecial:
3124         case Bytecodes::_invokestatic:
3125         case Bytecodes::_invokeinterface:
3126           {
3127             Bytecode_invoke invoke(sd->method(), sd->bci());
3128             st->print(" ");
3129             if (invoke.name() != NULL)
3130               invoke.name()->print_symbol_on(st);
3131             else
3132               st->print("<UNKNOWN>");
3133             break;
3134           }
3135         case Bytecodes::_getfield:
3136         case Bytecodes::_putfield:
3137         case Bytecodes::_getstatic:
3138         case Bytecodes::_putstatic:
3139           {
3140             Bytecode_field field(sd->method(), sd->bci());
3141             st->print(" ");
3142             if (field.name() != NULL)
3143               field.name()->print_symbol_on(st);
3144             else
3145               st->print("<UNKNOWN>");
3146           }
3147         }
3148       }
3149     }
3150 
3151     // Print all scopes
3152     for (;sd != NULL; sd = sd->sender()) {
3153       st->move_to(column);
3154       st->print("; -");
3155       if (sd->method() == NULL) {
3156         st->print("method is NULL");
3157       } else {
3158         sd->method()->print_short_name(st);
3159       }
3160       int lineno = sd->method()->line_number_from_bci(sd->bci());
3161       if (lineno != -1) {
3162         st->print("@%d (line %d)", sd->bci(), lineno);
3163       } else {
3164         st->print("@%d", sd->bci());
3165       }
3166       st->cr();
3167     }
3168   }
3169 
3170   // Print relocation information
3171   const char* str = reloc_string_for(begin, end);
3172   if (str != NULL) {
3173     if (sd != NULL) st->cr();
3174     st->move_to(column);
3175     st->print(";   {%s}", str);
3176   }
3177   int cont_offset = ImplicitExceptionTable(this).at(begin - code_begin());
3178   if (cont_offset != 0) {
3179     st->move_to(column);
3180     st->print("; implicit exception: dispatches to " INTPTR_FORMAT, code_begin() + cont_offset);
3181   }
3182 
3183 }
3184 
3185 #ifndef PRODUCT
3186 
3187 void nmethod::print_value_on(outputStream* st) const {
3188   st->print("nmethod");
3189   print_on(st, NULL);
3190 }
3191 
3192 void nmethod::print_calls(outputStream* st) {
3193   RelocIterator iter(this);
3194   while (iter.next()) {
3195     switch (iter.type()) {
3196     case relocInfo::virtual_call_type:
3197     case relocInfo::opt_virtual_call_type: {
3198       VerifyMutexLocker mc(CompiledIC_lock);
3199       CompiledIC_at(&iter)->print();
3200       break;
3201     }
3202     case relocInfo::static_call_type:
3203       st->print_cr("Static call at " INTPTR_FORMAT, iter.reloc()->addr());
3204       compiledStaticCall_at(iter.reloc())->print();
3205       break;
3206     }
3207   }
3208 }
3209 
3210 void nmethod::print_handler_table() {
3211   ExceptionHandlerTable(this).print();
3212 }
3213 
3214 void nmethod::print_nul_chk_table() {
3215   ImplicitExceptionTable(this).print(code_begin());
3216 }
3217 
3218 void nmethod::print_statistics() {
3219   ttyLocker ttyl;
3220   if (xtty != NULL)  xtty->head("statistics type='nmethod'");
3221   nmethod_stats.print_native_nmethod_stats();
3222   nmethod_stats.print_nmethod_stats();
3223   DebugInformationRecorder::print_statistics();
3224   nmethod_stats.print_pc_stats();
3225   Dependencies::print_statistics();
3226   if (xtty != NULL)  xtty->tail("statistics");
3227 }
3228 
3229 #endif // PRODUCT