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, CompLevel_none) 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, CompLevel_none) 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, comp_level)
 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, int comp_level) throw () {
 807   // With a SegmentedCodeCache, nmethods are allocated on separate heaps and therefore do not share memory
 808   // with critical CodeBlobs. We define the allocation as critical to make sure all code heap memory is used.
 809   bool is_critical = SegmentedCodeCache;
 810   return CodeCache::allocate(nmethod_size, CodeCache::get_code_blob_type(comp_level), is_critical);
 811 }
 812 
 813 nmethod::nmethod(
 814   Method* method,
 815   int nmethod_size,
 816   int compile_id,
 817   int entry_bci,
 818   CodeOffsets* offsets,
 819   int orig_pc_offset,
 820   DebugInformationRecorder* debug_info,
 821   Dependencies* dependencies,
 822   CodeBuffer *code_buffer,
 823   int frame_size,
 824   OopMapSet* oop_maps,
 825   ExceptionHandlerTable* handler_table,
 826   ImplicitExceptionTable* nul_chk_table,
 827   AbstractCompiler* compiler,
 828   int comp_level
 829   )
 830   : CodeBlob("nmethod", code_buffer, sizeof(nmethod),
 831              nmethod_size, offsets->value(CodeOffsets::Frame_Complete), frame_size, oop_maps),
 832   _native_receiver_sp_offset(in_ByteSize(-1)),
 833   _native_basic_lock_sp_offset(in_ByteSize(-1))
 834 {
 835   assert(debug_info->oop_recorder() == code_buffer->oop_recorder(), "shared OR");
 836   {
 837     debug_only(No_Safepoint_Verifier nsv;)
 838     assert_locked_or_safepoint(CodeCache_lock);
 839 
 840     init_defaults();
 841     _method                  = method;
 842     _entry_bci               = entry_bci;
 843     _compile_id              = compile_id;
 844     _comp_level              = comp_level;
 845     _compiler                = compiler;
 846     _orig_pc_offset          = orig_pc_offset;
 847     _hotness_counter         = NMethodSweeper::hotness_counter_reset_val();
 848 
 849     // Section offsets
 850     _consts_offset           = content_offset()      + code_buffer->total_offset_of(code_buffer->consts());
 851     _stub_offset             = content_offset()      + code_buffer->total_offset_of(code_buffer->stubs());
 852 
 853     // Exception handler and deopt handler are in the stub section
 854     assert(offsets->value(CodeOffsets::Exceptions) != -1, "must be set");
 855     assert(offsets->value(CodeOffsets::Deopt     ) != -1, "must be set");
 856     _exception_offset        = _stub_offset          + offsets->value(CodeOffsets::Exceptions);
 857     _deoptimize_offset       = _stub_offset          + offsets->value(CodeOffsets::Deopt);
 858     if (offsets->value(CodeOffsets::DeoptMH) != -1) {
 859       _deoptimize_mh_offset  = _stub_offset          + offsets->value(CodeOffsets::DeoptMH);
 860     } else {
 861       _deoptimize_mh_offset  = -1;
 862     }
 863     if (offsets->value(CodeOffsets::UnwindHandler) != -1) {
 864       _unwind_handler_offset = code_offset()         + offsets->value(CodeOffsets::UnwindHandler);
 865     } else {
 866       _unwind_handler_offset = -1;
 867     }
 868 
 869     _oops_offset             = data_offset();
 870     _metadata_offset         = _oops_offset          + round_to(code_buffer->total_oop_size(), oopSize);
 871     _scopes_data_offset      = _metadata_offset      + round_to(code_buffer->total_metadata_size(), wordSize);
 872 
 873     _scopes_pcs_offset       = _scopes_data_offset   + round_to(debug_info->data_size       (), oopSize);
 874     _dependencies_offset     = _scopes_pcs_offset    + adjust_pcs_size(debug_info->pcs_size());
 875     _handler_table_offset    = _dependencies_offset  + round_to(dependencies->size_in_bytes (), oopSize);
 876     _nul_chk_table_offset    = _handler_table_offset + round_to(handler_table->size_in_bytes(), oopSize);
 877     _nmethod_end_offset      = _nul_chk_table_offset + round_to(nul_chk_table->size_in_bytes(), oopSize);
 878 
 879     _entry_point             = code_begin()          + offsets->value(CodeOffsets::Entry);
 880     _verified_entry_point    = code_begin()          + offsets->value(CodeOffsets::Verified_Entry);
 881     _osr_entry_point         = code_begin()          + offsets->value(CodeOffsets::OSR_Entry);
 882     _exception_cache         = NULL;
 883     _pc_desc_cache.reset_to(scopes_pcs_begin());
 884 
 885     // Copy contents of ScopeDescRecorder to nmethod
 886     code_buffer->copy_values_to(this);
 887     debug_info->copy_to(this);
 888     dependencies->copy_to(this);
 889     if (ScavengeRootsInCode) {
 890       if (detect_scavenge_root_oops()) {
 891         CodeCache::add_scavenge_root_nmethod(this);
 892       }
 893       Universe::heap()->register_nmethod(this);
 894     }
 895     debug_only(verify_scavenge_root_oops());
 896 
 897     CodeCache::commit(this);
 898 
 899     // Copy contents of ExceptionHandlerTable to nmethod
 900     handler_table->copy_to(this);
 901     nul_chk_table->copy_to(this);
 902 
 903     // we use the information of entry points to find out if a method is
 904     // static or non static
 905     assert(compiler->is_c2() ||
 906            _method->is_static() == (entry_point() == _verified_entry_point),
 907            " entry points must be same for static methods and vice versa");
 908   }
 909 
 910   bool printnmethods = PrintNMethods
 911     || CompilerOracle::should_print(_method)
 912     || CompilerOracle::has_option_string(_method, "PrintNMethods");
 913   if (printnmethods || PrintDebugInfo || PrintRelocations || PrintDependencies || PrintExceptionHandlers) {
 914     print_nmethod(printnmethods);
 915   }
 916 }
 917 
 918 
 919 // Print a short set of xml attributes to identify this nmethod.  The
 920 // output should be embedded in some other element.
 921 void nmethod::log_identity(xmlStream* log) const {
 922   log->print(" compile_id='%d'", compile_id());
 923   const char* nm_kind = compile_kind();
 924   if (nm_kind != NULL)  log->print(" compile_kind='%s'", nm_kind);
 925   if (compiler() != NULL) {
 926     log->print(" compiler='%s'", compiler()->name());
 927   }
 928   if (TieredCompilation) {
 929     log->print(" level='%d'", comp_level());
 930   }
 931 }
 932 
 933 
 934 #define LOG_OFFSET(log, name)                    \
 935   if ((intptr_t)name##_end() - (intptr_t)name##_begin()) \
 936     log->print(" " XSTR(name) "_offset='%d'"    , \
 937                (intptr_t)name##_begin() - (intptr_t)this)
 938 
 939 
 940 void nmethod::log_new_nmethod() const {
 941   if (LogCompilation && xtty != NULL) {
 942     ttyLocker ttyl;
 943     HandleMark hm;
 944     xtty->begin_elem("nmethod");
 945     log_identity(xtty);
 946     xtty->print(" entry='" INTPTR_FORMAT "' size='%d'", code_begin(), size());
 947     xtty->print(" address='" INTPTR_FORMAT "'", (intptr_t) this);
 948 
 949     LOG_OFFSET(xtty, relocation);
 950     LOG_OFFSET(xtty, consts);
 951     LOG_OFFSET(xtty, insts);
 952     LOG_OFFSET(xtty, stub);
 953     LOG_OFFSET(xtty, scopes_data);
 954     LOG_OFFSET(xtty, scopes_pcs);
 955     LOG_OFFSET(xtty, dependencies);
 956     LOG_OFFSET(xtty, handler_table);
 957     LOG_OFFSET(xtty, nul_chk_table);
 958     LOG_OFFSET(xtty, oops);
 959 
 960     xtty->method(method());
 961     xtty->stamp();
 962     xtty->end_elem();
 963   }
 964 }
 965 
 966 #undef LOG_OFFSET
 967 
 968 
 969 // Print out more verbose output usually for a newly created nmethod.
 970 void nmethod::print_on(outputStream* st, const char* msg) const {
 971   if (st != NULL) {
 972     ttyLocker ttyl;
 973     if (WizardMode) {
 974       CompileTask::print_compilation(st, this, msg, /*short_form:*/ true);
 975       st->print_cr(" (" INTPTR_FORMAT ")", this);
 976     } else {
 977       CompileTask::print_compilation(st, this, msg, /*short_form:*/ false);
 978     }
 979   }
 980 }
 981 
 982 
 983 void nmethod::print_nmethod(bool printmethod) {
 984   ttyLocker ttyl;  // keep the following output all in one block
 985   if (xtty != NULL) {
 986     xtty->begin_head("print_nmethod");
 987     xtty->stamp();
 988     xtty->end_head();
 989   }
 990   // print the header part first
 991   print();
 992   // then print the requested information
 993   if (printmethod) {
 994     print_code();
 995     print_pcs();
 996     if (oop_maps()) {
 997       oop_maps()->print();
 998     }
 999   }
1000   if (PrintDebugInfo) {
1001     print_scopes();
1002   }
1003   if (PrintRelocations) {
1004     print_relocations();
1005   }
1006   if (PrintDependencies) {
1007     print_dependencies();
1008   }
1009   if (PrintExceptionHandlers) {
1010     print_handler_table();
1011     print_nul_chk_table();
1012   }
1013   if (xtty != NULL) {
1014     xtty->tail("print_nmethod");
1015   }
1016 }
1017 
1018 
1019 // Promote one word from an assembly-time handle to a live embedded oop.
1020 inline void nmethod::initialize_immediate_oop(oop* dest, jobject handle) {
1021   if (handle == NULL ||
1022       // As a special case, IC oops are initialized to 1 or -1.
1023       handle == (jobject) Universe::non_oop_word()) {
1024     (*dest) = (oop) handle;
1025   } else {
1026     (*dest) = JNIHandles::resolve_non_null(handle);
1027   }
1028 }
1029 
1030 
1031 // Have to have the same name because it's called by a template
1032 void nmethod::copy_values(GrowableArray<jobject>* array) {
1033   int length = array->length();
1034   assert((address)(oops_begin() + length) <= (address)oops_end(), "oops big enough");
1035   oop* dest = oops_begin();
1036   for (int index = 0 ; index < length; index++) {
1037     initialize_immediate_oop(&dest[index], array->at(index));
1038   }
1039 
1040   // Now we can fix up all the oops in the code.  We need to do this
1041   // in the code because the assembler uses jobjects as placeholders.
1042   // The code and relocations have already been initialized by the
1043   // CodeBlob constructor, so it is valid even at this early point to
1044   // iterate over relocations and patch the code.
1045   fix_oop_relocations(NULL, NULL, /*initialize_immediates=*/ true);
1046 }
1047 
1048 void nmethod::copy_values(GrowableArray<Metadata*>* array) {
1049   int length = array->length();
1050   assert((address)(metadata_begin() + length) <= (address)metadata_end(), "big enough");
1051   Metadata** dest = metadata_begin();
1052   for (int index = 0 ; index < length; index++) {
1053     dest[index] = array->at(index);
1054   }
1055 }
1056 
1057 bool nmethod::is_at_poll_return(address pc) {
1058   RelocIterator iter(this, pc, pc+1);
1059   while (iter.next()) {
1060     if (iter.type() == relocInfo::poll_return_type)
1061       return true;
1062   }
1063   return false;
1064 }
1065 
1066 
1067 bool nmethod::is_at_poll_or_poll_return(address pc) {
1068   RelocIterator iter(this, pc, pc+1);
1069   while (iter.next()) {
1070     relocInfo::relocType t = iter.type();
1071     if (t == relocInfo::poll_return_type || t == relocInfo::poll_type)
1072       return true;
1073   }
1074   return false;
1075 }
1076 
1077 
1078 void nmethod::fix_oop_relocations(address begin, address end, bool initialize_immediates) {
1079   // re-patch all oop-bearing instructions, just in case some oops moved
1080   RelocIterator iter(this, begin, end);
1081   while (iter.next()) {
1082     if (iter.type() == relocInfo::oop_type) {
1083       oop_Relocation* reloc = iter.oop_reloc();
1084       if (initialize_immediates && reloc->oop_is_immediate()) {
1085         oop* dest = reloc->oop_addr();
1086         initialize_immediate_oop(dest, (jobject) *dest);
1087       }
1088       // Refresh the oop-related bits of this instruction.
1089       reloc->fix_oop_relocation();
1090     } else if (iter.type() == relocInfo::metadata_type) {
1091       metadata_Relocation* reloc = iter.metadata_reloc();
1092       reloc->fix_metadata_relocation();
1093     }
1094   }
1095 }
1096 
1097 
1098 void nmethod::verify_oop_relocations() {
1099   // Ensure sure that the code matches the current oop values
1100   RelocIterator iter(this, NULL, NULL);
1101   while (iter.next()) {
1102     if (iter.type() == relocInfo::oop_type) {
1103       oop_Relocation* reloc = iter.oop_reloc();
1104       if (!reloc->oop_is_immediate()) {
1105         reloc->verify_oop_relocation();
1106       }
1107     }
1108   }
1109 }
1110 
1111 
1112 ScopeDesc* nmethod::scope_desc_at(address pc) {
1113   PcDesc* pd = pc_desc_at(pc);
1114   guarantee(pd != NULL, "scope must be present");
1115   return new ScopeDesc(this, pd->scope_decode_offset(),
1116                        pd->obj_decode_offset(), pd->should_reexecute(),
1117                        pd->return_oop());
1118 }
1119 
1120 
1121 void nmethod::clear_inline_caches() {
1122   assert(SafepointSynchronize::is_at_safepoint(), "cleaning of IC's only allowed at safepoint");
1123   if (is_zombie()) {
1124     return;
1125   }
1126 
1127   RelocIterator iter(this);
1128   while (iter.next()) {
1129     iter.reloc()->clear_inline_cache();
1130   }
1131 }
1132 
1133 // Clear ICStubs of all compiled ICs
1134 void nmethod::clear_ic_stubs() {
1135   assert_locked_or_safepoint(CompiledIC_lock);
1136   RelocIterator iter(this);
1137   while(iter.next()) {
1138     if (iter.type() == relocInfo::virtual_call_type) {
1139       CompiledIC* ic = CompiledIC_at(&iter);
1140       ic->clear_ic_stub();
1141     }
1142   }
1143 }
1144 
1145 
1146 void nmethod::cleanup_inline_caches() {
1147 
1148   assert_locked_or_safepoint(CompiledIC_lock);
1149 
1150   // If the method is not entrant or zombie then a JMP is plastered over the
1151   // first few bytes.  If an oop in the old code was there, that oop
1152   // should not get GC'd.  Skip the first few bytes of oops on
1153   // not-entrant methods.
1154   address low_boundary = verified_entry_point();
1155   if (!is_in_use()) {
1156     low_boundary += NativeJump::instruction_size;
1157     // %%% Note:  On SPARC we patch only a 4-byte trap, not a full NativeJump.
1158     // This means that the low_boundary is going to be a little too high.
1159     // This shouldn't matter, since oops of non-entrant methods are never used.
1160     // In fact, why are we bothering to look at oops in a non-entrant method??
1161   }
1162 
1163   // Find all calls in an nmethod, and clear the ones that points to zombie methods
1164   ResourceMark rm;
1165   RelocIterator iter(this, low_boundary);
1166   while(iter.next()) {
1167     switch(iter.type()) {
1168       case relocInfo::virtual_call_type:
1169       case relocInfo::opt_virtual_call_type: {
1170         CompiledIC *ic = CompiledIC_at(&iter);
1171         // Ok, to lookup references to zombies here
1172         CodeBlob *cb = CodeCache::find_blob_unsafe(ic->ic_destination());
1173         if( cb != NULL && cb->is_nmethod() ) {
1174           nmethod* nm = (nmethod*)cb;
1175           // Clean inline caches pointing to both zombie and not_entrant methods
1176           if (!nm->is_in_use() || (nm->method()->code() != nm)) ic->set_to_clean();
1177         }
1178         break;
1179       }
1180       case relocInfo::static_call_type: {
1181         CompiledStaticCall *csc = compiledStaticCall_at(iter.reloc());
1182         CodeBlob *cb = CodeCache::find_blob_unsafe(csc->destination());
1183         if( cb != NULL && cb->is_nmethod() ) {
1184           nmethod* nm = (nmethod*)cb;
1185           // Clean inline caches pointing to both zombie and not_entrant methods
1186           if (!nm->is_in_use() || (nm->method()->code() != nm)) csc->set_to_clean();
1187         }
1188         break;
1189       }
1190     }
1191   }
1192 }
1193 
1194 void nmethod::verify_clean_inline_caches() {
1195   assert_locked_or_safepoint(CompiledIC_lock);
1196 
1197   // If the method is not entrant or zombie then a JMP is plastered over the
1198   // first few bytes.  If an oop in the old code was there, that oop
1199   // should not get GC'd.  Skip the first few bytes of oops on
1200   // not-entrant methods.
1201   address low_boundary = verified_entry_point();
1202   if (!is_in_use()) {
1203     low_boundary += NativeJump::instruction_size;
1204     // %%% Note:  On SPARC we patch only a 4-byte trap, not a full NativeJump.
1205     // This means that the low_boundary is going to be a little too high.
1206     // This shouldn't matter, since oops of non-entrant methods are never used.
1207     // In fact, why are we bothering to look at oops in a non-entrant method??
1208   }
1209 
1210   ResourceMark rm;
1211   RelocIterator iter(this, low_boundary);
1212   while(iter.next()) {
1213     switch(iter.type()) {
1214       case relocInfo::virtual_call_type:
1215       case relocInfo::opt_virtual_call_type: {
1216         CompiledIC *ic = CompiledIC_at(&iter);
1217         // Ok, to lookup references to zombies here
1218         CodeBlob *cb = CodeCache::find_blob_unsafe(ic->ic_destination());
1219         if( cb != NULL && cb->is_nmethod() ) {
1220           nmethod* nm = (nmethod*)cb;
1221           // Verify that inline caches pointing to both zombie and not_entrant methods are clean
1222           if (!nm->is_in_use() || (nm->method()->code() != nm)) {
1223             assert(ic->is_clean(), "IC should be clean");
1224           }
1225         }
1226         break;
1227       }
1228       case relocInfo::static_call_type: {
1229         CompiledStaticCall *csc = compiledStaticCall_at(iter.reloc());
1230         CodeBlob *cb = CodeCache::find_blob_unsafe(csc->destination());
1231         if( cb != NULL && cb->is_nmethod() ) {
1232           nmethod* nm = (nmethod*)cb;
1233           // Verify that inline caches pointing to both zombie and not_entrant methods are clean
1234           if (!nm->is_in_use() || (nm->method()->code() != nm)) {
1235             assert(csc->is_clean(), "IC should be clean");
1236           }
1237         }
1238         break;
1239       }
1240     }
1241   }
1242 }
1243 
1244 int nmethod::verify_icholder_relocations() {
1245   int count = 0;
1246 
1247   RelocIterator iter(this);
1248   while(iter.next()) {
1249     if (iter.type() == relocInfo::virtual_call_type) {
1250       if (CompiledIC::is_icholder_call_site(iter.virtual_call_reloc())) {
1251         CompiledIC *ic = CompiledIC_at(&iter);
1252         if (TraceCompiledIC) {
1253           tty->print("noticed icholder " INTPTR_FORMAT " ", p2i(ic->cached_icholder()));
1254           ic->print();
1255         }
1256         assert(ic->cached_icholder() != NULL, "must be non-NULL");
1257         count++;
1258       }
1259     }
1260   }
1261 
1262   return count;
1263 }
1264 
1265 // This is a private interface with the sweeper.
1266 void nmethod::mark_as_seen_on_stack() {
1267   assert(is_alive(), "Must be an alive method");
1268   // Set the traversal mark to ensure that the sweeper does 2
1269   // cleaning passes before moving to zombie.
1270   set_stack_traversal_mark(NMethodSweeper::traversal_count());
1271 }
1272 
1273 // Tell if a non-entrant method can be converted to a zombie (i.e.,
1274 // there are no activations on the stack, not in use by the VM,
1275 // and not in use by the ServiceThread)
1276 bool nmethod::can_not_entrant_be_converted() {
1277   assert(is_not_entrant(), "must be a non-entrant method");
1278 
1279   // Since the nmethod sweeper only does partial sweep the sweeper's traversal
1280   // count can be greater than the stack traversal count before it hits the
1281   // nmethod for the second time.
1282   return stack_traversal_mark()+1 < NMethodSweeper::traversal_count() &&
1283          !is_locked_by_vm();
1284 }
1285 
1286 void nmethod::inc_decompile_count() {
1287   if (!is_compiled_by_c2()) return;
1288   // Could be gated by ProfileTraps, but do not bother...
1289   Method* m = method();
1290   if (m == NULL)  return;
1291   MethodData* mdo = m->method_data();
1292   if (mdo == NULL)  return;
1293   // There is a benign race here.  See comments in methodData.hpp.
1294   mdo->inc_decompile_count();
1295 }
1296 
1297 void nmethod::increase_unloading_clock() {
1298   _global_unloading_clock++;
1299   if (_global_unloading_clock == 0) {
1300     // _nmethods are allocated with _unloading_clock == 0,
1301     // so 0 is never used as a clock value.
1302     _global_unloading_clock = 1;
1303   }
1304 }
1305 
1306 void nmethod::set_unloading_clock(unsigned char unloading_clock) {
1307   OrderAccess::release_store((volatile jubyte*)&_unloading_clock, unloading_clock);
1308 }
1309 
1310 unsigned char nmethod::unloading_clock() {
1311   return (unsigned char)OrderAccess::load_acquire((volatile jubyte*)&_unloading_clock);
1312 }
1313 
1314 void nmethod::make_unloaded(BoolObjectClosure* is_alive, oop cause) {
1315 
1316   post_compiled_method_unload();
1317 
1318   // Since this nmethod is being unloaded, make sure that dependencies
1319   // recorded in instanceKlasses get flushed and pass non-NULL closure to
1320   // indicate that this work is being done during a GC.
1321   assert(Universe::heap()->is_gc_active(), "should only be called during gc");
1322   assert(is_alive != NULL, "Should be non-NULL");
1323   // A non-NULL is_alive closure indicates that this is being called during GC.
1324   flush_dependencies(is_alive);
1325 
1326   // Break cycle between nmethod & method
1327   if (TraceClassUnloading && WizardMode) {
1328     tty->print_cr("[Class unloading: Making nmethod " INTPTR_FORMAT
1329                   " unloadable], Method*(" INTPTR_FORMAT
1330                   "), cause(" INTPTR_FORMAT ")",
1331                   this, (address)_method, (address)cause);
1332     if (!Universe::heap()->is_gc_active())
1333       cause->klass()->print();
1334   }
1335   // Unlink the osr method, so we do not look this up again
1336   if (is_osr_method()) {
1337     invalidate_osr_method();
1338   }
1339   // If _method is already NULL the Method* is about to be unloaded,
1340   // so we don't have to break the cycle. Note that it is possible to
1341   // have the Method* live here, in case we unload the nmethod because
1342   // it is pointing to some oop (other than the Method*) being unloaded.
1343   if (_method != NULL) {
1344     // OSR methods point to the Method*, but the Method* does not
1345     // point back!
1346     if (_method->code() == this) {
1347       _method->clear_code(); // Break a cycle
1348     }
1349     _method = NULL;            // Clear the method of this dead nmethod
1350   }
1351   // Make the class unloaded - i.e., change state and notify sweeper
1352   assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
1353   if (is_in_use()) {
1354     // Transitioning directly from live to unloaded -- so
1355     // we need to force a cache clean-up; remember this
1356     // for later on.
1357     CodeCache::set_needs_cache_clean(true);
1358   }
1359 
1360   // Unregister must be done before the state change
1361   Universe::heap()->unregister_nmethod(this);
1362 
1363   _state = unloaded;
1364 
1365   // Log the unloading.
1366   log_state_change();
1367 
1368   // The Method* is gone at this point
1369   assert(_method == NULL, "Tautology");
1370 
1371   set_osr_link(NULL);
1372   //set_scavenge_root_link(NULL); // done by prune_scavenge_root_nmethods
1373   NMethodSweeper::report_state_change(this);
1374 }
1375 
1376 void nmethod::invalidate_osr_method() {
1377   assert(_entry_bci != InvocationEntryBci, "wrong kind of nmethod");
1378   // Remove from list of active nmethods
1379   if (method() != NULL)
1380     method()->method_holder()->remove_osr_nmethod(this);
1381 }
1382 
1383 void nmethod::log_state_change() const {
1384   if (LogCompilation) {
1385     if (xtty != NULL) {
1386       ttyLocker ttyl;  // keep the following output all in one block
1387       if (_state == unloaded) {
1388         xtty->begin_elem("make_unloaded thread='" UINTX_FORMAT "'",
1389                          os::current_thread_id());
1390       } else {
1391         xtty->begin_elem("make_not_entrant thread='" UINTX_FORMAT "'%s",
1392                          os::current_thread_id(),
1393                          (_state == zombie ? " zombie='1'" : ""));
1394       }
1395       log_identity(xtty);
1396       xtty->stamp();
1397       xtty->end_elem();
1398     }
1399   }
1400   if (PrintCompilation && _state != unloaded) {
1401     print_on(tty, _state == zombie ? "made zombie" : "made not entrant");
1402   }
1403 }
1404 
1405 /**
1406  * Common functionality for both make_not_entrant and make_zombie
1407  */
1408 bool nmethod::make_not_entrant_or_zombie(unsigned int state) {
1409   assert(state == zombie || state == not_entrant, "must be zombie or not_entrant");
1410   assert(!is_zombie(), "should not already be a zombie");
1411 
1412   // Make sure neither the nmethod nor the method is flushed in case of a safepoint in code below.
1413   nmethodLocker nml(this);
1414   methodHandle the_method(method());
1415   No_Safepoint_Verifier nsv;
1416 
1417   // during patching, depending on the nmethod state we must notify the GC that
1418   // code has been unloaded, unregistering it. We cannot do this right while
1419   // holding the Patching_lock because we need to use the CodeCache_lock. This
1420   // would be prone to deadlocks.
1421   // This flag is used to remember whether we need to later lock and unregister.
1422   bool nmethod_needs_unregister = false;
1423 
1424   {
1425     // invalidate osr nmethod before acquiring the patching lock since
1426     // they both acquire leaf locks and we don't want a deadlock.
1427     // This logic is equivalent to the logic below for patching the
1428     // verified entry point of regular methods.
1429     if (is_osr_method()) {
1430       // this effectively makes the osr nmethod not entrant
1431       invalidate_osr_method();
1432     }
1433 
1434     // Enter critical section.  Does not block for safepoint.
1435     MutexLockerEx pl(Patching_lock, Mutex::_no_safepoint_check_flag);
1436 
1437     if (_state == state) {
1438       // another thread already performed this transition so nothing
1439       // to do, but return false to indicate this.
1440       return false;
1441     }
1442 
1443     // The caller can be calling the method statically or through an inline
1444     // cache call.
1445     if (!is_osr_method() && !is_not_entrant()) {
1446       NativeJump::patch_verified_entry(entry_point(), verified_entry_point(),
1447                   SharedRuntime::get_handle_wrong_method_stub());
1448     }
1449 
1450     if (is_in_use()) {
1451       // It's a true state change, so mark the method as decompiled.
1452       // Do it only for transition from alive.
1453       inc_decompile_count();
1454     }
1455 
1456     // If the state is becoming a zombie, signal to unregister the nmethod with
1457     // the heap.
1458     // This nmethod may have already been unloaded during a full GC.
1459     if ((state == zombie) && !is_unloaded()) {
1460       nmethod_needs_unregister = true;
1461     }
1462 
1463     // Must happen before state change. Otherwise we have a race condition in
1464     // nmethod::can_not_entrant_be_converted(). I.e., a method can immediately
1465     // transition its state from 'not_entrant' to 'zombie' without having to wait
1466     // for stack scanning.
1467     if (state == not_entrant) {
1468       mark_as_seen_on_stack();
1469       OrderAccess::storestore();
1470     }
1471 
1472     // Change state
1473     _state = state;
1474 
1475     // Log the transition once
1476     log_state_change();
1477 
1478     // Remove nmethod from method.
1479     // We need to check if both the _code and _from_compiled_code_entry_point
1480     // refer to this nmethod because there is a race in setting these two fields
1481     // in Method* as seen in bugid 4947125.
1482     // If the vep() points to the zombie nmethod, the memory for the nmethod
1483     // could be flushed and the compiler and vtable stubs could still call
1484     // through it.
1485     if (method() != NULL && (method()->code() == this ||
1486                              method()->from_compiled_entry() == verified_entry_point())) {
1487       HandleMark hm;
1488       method()->clear_code();
1489     }
1490   } // leave critical region under Patching_lock
1491 
1492   // When the nmethod becomes zombie it is no longer alive so the
1493   // dependencies must be flushed.  nmethods in the not_entrant
1494   // state will be flushed later when the transition to zombie
1495   // happens or they get unloaded.
1496   if (state == zombie) {
1497     {
1498       // Flushing dependecies must be done before any possible
1499       // safepoint can sneak in, otherwise the oops used by the
1500       // dependency logic could have become stale.
1501       MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
1502       if (nmethod_needs_unregister) {
1503         Universe::heap()->unregister_nmethod(this);
1504       }
1505       flush_dependencies(NULL);
1506     }
1507 
1508     // zombie only - if a JVMTI agent has enabled the CompiledMethodUnload
1509     // event and it hasn't already been reported for this nmethod then
1510     // report it now. The event may have been reported earilier if the GC
1511     // marked it for unloading). JvmtiDeferredEventQueue support means
1512     // we no longer go to a safepoint here.
1513     post_compiled_method_unload();
1514 
1515 #ifdef ASSERT
1516     // It's no longer safe to access the oops section since zombie
1517     // nmethods aren't scanned for GC.
1518     _oops_are_stale = true;
1519 #endif
1520      // the Method may be reclaimed by class unloading now that the
1521      // nmethod is in zombie state
1522     set_method(NULL);
1523   } else {
1524     assert(state == not_entrant, "other cases may need to be handled differently");
1525   }
1526 
1527   if (TraceCreateZombies) {
1528     tty->print_cr("nmethod <" INTPTR_FORMAT "> code made %s", this, (state == not_entrant) ? "not entrant" : "zombie");
1529   }
1530 
1531   NMethodSweeper::report_state_change(this);
1532   return true;
1533 }
1534 
1535 void nmethod::flush() {
1536   // Note that there are no valid oops in the nmethod anymore.
1537   assert(is_zombie() || (is_osr_method() && is_unloaded()), "must be a zombie method");
1538   assert(is_marked_for_reclamation() || (is_osr_method() && is_unloaded()), "must be marked for reclamation");
1539 
1540   assert (!is_locked_by_vm(), "locked methods shouldn't be flushed");
1541   assert_locked_or_safepoint(CodeCache_lock);
1542 
1543   // completely deallocate this method
1544   Events::log(JavaThread::current(), "flushing nmethod " INTPTR_FORMAT, this);
1545   if (PrintMethodFlushing) {
1546     tty->print_cr("*flushing nmethod %3d/" INTPTR_FORMAT ". Live blobs:" UINT32_FORMAT "/Free CodeCache:" SIZE_FORMAT "Kb",
1547         _compile_id, this, CodeCache::nof_blobs(), CodeCache::unallocated_capacity(CodeCache::get_code_blob_type(_comp_level))/1024);
1548   }
1549 
1550   // We need to deallocate any ExceptionCache data.
1551   // Note that we do not need to grab the nmethod lock for this, it
1552   // better be thread safe if we're disposing of it!
1553   ExceptionCache* ec = exception_cache();
1554   set_exception_cache(NULL);
1555   while(ec != NULL) {
1556     ExceptionCache* next = ec->next();
1557     delete ec;
1558     ec = next;
1559   }
1560 
1561   if (on_scavenge_root_list()) {
1562     CodeCache::drop_scavenge_root_nmethod(this);
1563   }
1564 
1565 #ifdef SHARK
1566   ((SharkCompiler *) compiler())->free_compiled_method(insts_begin());
1567 #endif // SHARK
1568 
1569   ((CodeBlob*)(this))->flush();
1570 
1571   CodeCache::free(this);
1572 }
1573 
1574 //
1575 // Notify all classes this nmethod is dependent on that it is no
1576 // longer dependent. This should only be called in two situations.
1577 // First, when a nmethod transitions to a zombie all dependents need
1578 // to be clear.  Since zombification happens at a safepoint there's no
1579 // synchronization issues.  The second place is a little more tricky.
1580 // During phase 1 of mark sweep class unloading may happen and as a
1581 // result some nmethods may get unloaded.  In this case the flushing
1582 // of dependencies must happen during phase 1 since after GC any
1583 // dependencies in the unloaded nmethod won't be updated, so
1584 // traversing the dependency information in unsafe.  In that case this
1585 // function is called with a non-NULL argument and this function only
1586 // notifies instanceKlasses that are reachable
1587 
1588 void nmethod::flush_dependencies(BoolObjectClosure* is_alive) {
1589   assert_locked_or_safepoint(CodeCache_lock);
1590   assert(Universe::heap()->is_gc_active() == (is_alive != NULL),
1591   "is_alive is non-NULL if and only if we are called during GC");
1592   if (!has_flushed_dependencies()) {
1593     set_has_flushed_dependencies();
1594     for (Dependencies::DepStream deps(this); deps.next(); ) {
1595       Klass* klass = deps.context_type();
1596       if (klass == NULL)  continue;  // ignore things like evol_method
1597 
1598       // During GC the is_alive closure is non-NULL, and is used to
1599       // determine liveness of dependees that need to be updated.
1600       if (is_alive == NULL || klass->is_loader_alive(is_alive)) {
1601         InstanceKlass::cast(klass)->remove_dependent_nmethod(this);
1602       }
1603     }
1604   }
1605 }
1606 
1607 
1608 // If this oop is not live, the nmethod can be unloaded.
1609 bool nmethod::can_unload(BoolObjectClosure* is_alive, oop* root, bool unloading_occurred) {
1610   assert(root != NULL, "just checking");
1611   oop obj = *root;
1612   if (obj == NULL || is_alive->do_object_b(obj)) {
1613       return false;
1614   }
1615 
1616   // If ScavengeRootsInCode is true, an nmethod might be unloaded
1617   // simply because one of its constant oops has gone dead.
1618   // No actual classes need to be unloaded in order for this to occur.
1619   assert(unloading_occurred || ScavengeRootsInCode, "Inconsistency in unloading");
1620   make_unloaded(is_alive, obj);
1621   return true;
1622 }
1623 
1624 // ------------------------------------------------------------------
1625 // post_compiled_method_load_event
1626 // new method for install_code() path
1627 // Transfer information from compilation to jvmti
1628 void nmethod::post_compiled_method_load_event() {
1629 
1630   Method* moop = method();
1631   HOTSPOT_COMPILED_METHOD_LOAD(
1632       (char *) moop->klass_name()->bytes(),
1633       moop->klass_name()->utf8_length(),
1634       (char *) moop->name()->bytes(),
1635       moop->name()->utf8_length(),
1636       (char *) moop->signature()->bytes(),
1637       moop->signature()->utf8_length(),
1638       insts_begin(), insts_size());
1639 
1640   if (JvmtiExport::should_post_compiled_method_load() ||
1641       JvmtiExport::should_post_compiled_method_unload()) {
1642     get_and_cache_jmethod_id();
1643   }
1644 
1645   if (JvmtiExport::should_post_compiled_method_load()) {
1646     // Let the Service thread (which is a real Java thread) post the event
1647     MutexLockerEx ml(Service_lock, Mutex::_no_safepoint_check_flag);
1648     JvmtiDeferredEventQueue::enqueue(
1649       JvmtiDeferredEvent::compiled_method_load_event(this));
1650   }
1651 }
1652 
1653 jmethodID nmethod::get_and_cache_jmethod_id() {
1654   if (_jmethod_id == NULL) {
1655     // Cache the jmethod_id since it can no longer be looked up once the
1656     // method itself has been marked for unloading.
1657     _jmethod_id = method()->jmethod_id();
1658   }
1659   return _jmethod_id;
1660 }
1661 
1662 void nmethod::post_compiled_method_unload() {
1663   if (unload_reported()) {
1664     // During unloading we transition to unloaded and then to zombie
1665     // and the unloading is reported during the first transition.
1666     return;
1667   }
1668 
1669   assert(_method != NULL && !is_unloaded(), "just checking");
1670   DTRACE_METHOD_UNLOAD_PROBE(method());
1671 
1672   // If a JVMTI agent has enabled the CompiledMethodUnload event then
1673   // post the event. Sometime later this nmethod will be made a zombie
1674   // by the sweeper but the Method* will not be valid at that point.
1675   // If the _jmethod_id is null then no load event was ever requested
1676   // so don't bother posting the unload.  The main reason for this is
1677   // that the jmethodID is a weak reference to the Method* so if
1678   // it's being unloaded there's no way to look it up since the weak
1679   // ref will have been cleared.
1680   if (_jmethod_id != NULL && JvmtiExport::should_post_compiled_method_unload()) {
1681     assert(!unload_reported(), "already unloaded");
1682     JvmtiDeferredEvent event =
1683       JvmtiDeferredEvent::compiled_method_unload_event(this,
1684           _jmethod_id, insts_begin());
1685     if (SafepointSynchronize::is_at_safepoint()) {
1686       // Don't want to take the queueing lock. Add it as pending and
1687       // it will get enqueued later.
1688       JvmtiDeferredEventQueue::add_pending_event(event);
1689     } else {
1690       MutexLockerEx ml(Service_lock, Mutex::_no_safepoint_check_flag);
1691       JvmtiDeferredEventQueue::enqueue(event);
1692     }
1693   }
1694 
1695   // The JVMTI CompiledMethodUnload event can be enabled or disabled at
1696   // any time. As the nmethod is being unloaded now we mark it has
1697   // having the unload event reported - this will ensure that we don't
1698   // attempt to report the event in the unlikely scenario where the
1699   // event is enabled at the time the nmethod is made a zombie.
1700   set_unload_reported();
1701 }
1702 
1703 void static clean_ic_if_metadata_is_dead(CompiledIC *ic, BoolObjectClosure *is_alive) {
1704   if (ic->is_icholder_call()) {
1705     // The only exception is compiledICHolder oops which may
1706     // yet be marked below. (We check this further below).
1707     CompiledICHolder* cichk_oop = ic->cached_icholder();
1708     if (cichk_oop->holder_method()->method_holder()->is_loader_alive(is_alive) &&
1709         cichk_oop->holder_klass()->is_loader_alive(is_alive)) {
1710       return;
1711     }
1712   } else {
1713     Metadata* ic_oop = ic->cached_metadata();
1714     if (ic_oop != NULL) {
1715       if (ic_oop->is_klass()) {
1716         if (((Klass*)ic_oop)->is_loader_alive(is_alive)) {
1717           return;
1718         }
1719       } else if (ic_oop->is_method()) {
1720         if (((Method*)ic_oop)->method_holder()->is_loader_alive(is_alive)) {
1721           return;
1722         }
1723       } else {
1724         ShouldNotReachHere();
1725       }
1726     }
1727   }
1728 
1729   ic->set_to_clean();
1730 }
1731 
1732 // This is called at the end of the strong tracing/marking phase of a
1733 // GC to unload an nmethod if it contains otherwise unreachable
1734 // oops.
1735 
1736 void nmethod::do_unloading(BoolObjectClosure* is_alive, bool unloading_occurred) {
1737   // Make sure the oop's ready to receive visitors
1738   assert(!is_zombie() && !is_unloaded(),
1739          "should not call follow on zombie or unloaded nmethod");
1740 
1741   // If the method is not entrant then a JMP is plastered over the
1742   // first few bytes.  If an oop in the old code was there, that oop
1743   // should not get GC'd.  Skip the first few bytes of oops on
1744   // not-entrant methods.
1745   address low_boundary = verified_entry_point();
1746   if (is_not_entrant()) {
1747     low_boundary += NativeJump::instruction_size;
1748     // %%% Note:  On SPARC we patch only a 4-byte trap, not a full NativeJump.
1749     // (See comment above.)
1750   }
1751 
1752   // The RedefineClasses() API can cause the class unloading invariant
1753   // to no longer be true. See jvmtiExport.hpp for details.
1754   // Also, leave a debugging breadcrumb in local flag.
1755   bool a_class_was_redefined = JvmtiExport::has_redefined_a_class();
1756   if (a_class_was_redefined) {
1757     // This set of the unloading_occurred flag is done before the
1758     // call to post_compiled_method_unload() so that the unloading
1759     // of this nmethod is reported.
1760     unloading_occurred = true;
1761   }
1762 
1763   // Exception cache
1764   clean_exception_cache(is_alive);
1765 
1766   // If class unloading occurred we first iterate over all inline caches and
1767   // clear ICs where the cached oop is referring to an unloaded klass or method.
1768   // The remaining live cached oops will be traversed in the relocInfo::oop_type
1769   // iteration below.
1770   if (unloading_occurred) {
1771     RelocIterator iter(this, low_boundary);
1772     while(iter.next()) {
1773       if (iter.type() == relocInfo::virtual_call_type) {
1774         CompiledIC *ic = CompiledIC_at(&iter);
1775         clean_ic_if_metadata_is_dead(ic, is_alive);
1776       }
1777     }
1778   }
1779 
1780   // Compiled code
1781   {
1782   RelocIterator iter(this, low_boundary);
1783   while (iter.next()) {
1784     if (iter.type() == relocInfo::oop_type) {
1785       oop_Relocation* r = iter.oop_reloc();
1786       // In this loop, we must only traverse those oops directly embedded in
1787       // the code.  Other oops (oop_index>0) are seen as part of scopes_oops.
1788       assert(1 == (r->oop_is_immediate()) +
1789                   (r->oop_addr() >= oops_begin() && r->oop_addr() < oops_end()),
1790              "oop must be found in exactly one place");
1791       if (r->oop_is_immediate() && r->oop_value() != NULL) {
1792         if (can_unload(is_alive, r->oop_addr(), unloading_occurred)) {
1793           return;
1794         }
1795       }
1796     }
1797   }
1798   }
1799 
1800 
1801   // Scopes
1802   for (oop* p = oops_begin(); p < oops_end(); p++) {
1803     if (*p == Universe::non_oop_word())  continue;  // skip non-oops
1804     if (can_unload(is_alive, p, unloading_occurred)) {
1805       return;
1806     }
1807   }
1808 
1809   // Ensure that all metadata is still alive
1810   verify_metadata_loaders(low_boundary, is_alive);
1811 }
1812 
1813 template <class CompiledICorStaticCall>
1814 static bool clean_if_nmethod_is_unloaded(CompiledICorStaticCall *ic, address addr, BoolObjectClosure *is_alive, nmethod* from) {
1815   // Ok, to lookup references to zombies here
1816   CodeBlob *cb = CodeCache::find_blob_unsafe(addr);
1817   if (cb != NULL && cb->is_nmethod()) {
1818     nmethod* nm = (nmethod*)cb;
1819 
1820     if (nm->unloading_clock() != nmethod::global_unloading_clock()) {
1821       // The nmethod has not been processed yet.
1822       return true;
1823     }
1824 
1825     // Clean inline caches pointing to both zombie and not_entrant methods
1826     if (!nm->is_in_use() || (nm->method()->code() != nm)) {
1827       ic->set_to_clean();
1828       assert(ic->is_clean(), err_msg("nmethod " PTR_FORMAT "not clean %s", from, from->method()->name_and_sig_as_C_string()));
1829     }
1830   }
1831 
1832   return false;
1833 }
1834 
1835 static bool clean_if_nmethod_is_unloaded(CompiledIC *ic, BoolObjectClosure *is_alive, nmethod* from) {
1836   return clean_if_nmethod_is_unloaded(ic, ic->ic_destination(), is_alive, from);
1837 }
1838 
1839 static bool clean_if_nmethod_is_unloaded(CompiledStaticCall *csc, BoolObjectClosure *is_alive, nmethod* from) {
1840   return clean_if_nmethod_is_unloaded(csc, csc->destination(), is_alive, from);
1841 }
1842 
1843 bool nmethod::do_unloading_parallel(BoolObjectClosure* is_alive, bool unloading_occurred) {
1844   ResourceMark rm;
1845 
1846   // Make sure the oop's ready to receive visitors
1847   assert(!is_zombie() && !is_unloaded(),
1848          "should not call follow on zombie or unloaded nmethod");
1849 
1850   // If the method is not entrant then a JMP is plastered over the
1851   // first few bytes.  If an oop in the old code was there, that oop
1852   // should not get GC'd.  Skip the first few bytes of oops on
1853   // not-entrant methods.
1854   address low_boundary = verified_entry_point();
1855   if (is_not_entrant()) {
1856     low_boundary += NativeJump::instruction_size;
1857     // %%% Note:  On SPARC we patch only a 4-byte trap, not a full NativeJump.
1858     // (See comment above.)
1859   }
1860 
1861   // The RedefineClasses() API can cause the class unloading invariant
1862   // to no longer be true. See jvmtiExport.hpp for details.
1863   // Also, leave a debugging breadcrumb in local flag.
1864   bool a_class_was_redefined = JvmtiExport::has_redefined_a_class();
1865   if (a_class_was_redefined) {
1866     // This set of the unloading_occurred flag is done before the
1867     // call to post_compiled_method_unload() so that the unloading
1868     // of this nmethod is reported.
1869     unloading_occurred = true;
1870   }
1871 
1872   // Exception cache
1873   clean_exception_cache(is_alive);
1874 
1875   bool is_unloaded = false;
1876   bool postponed = false;
1877 
1878   RelocIterator iter(this, low_boundary);
1879   while(iter.next()) {
1880 
1881     switch (iter.type()) {
1882 
1883     case relocInfo::virtual_call_type:
1884       if (unloading_occurred) {
1885         // If class unloading occurred we first iterate over all inline caches and
1886         // clear ICs where the cached oop is referring to an unloaded klass or method.
1887         clean_ic_if_metadata_is_dead(CompiledIC_at(&iter), is_alive);
1888       }
1889 
1890       postponed |= clean_if_nmethod_is_unloaded(CompiledIC_at(&iter), is_alive, this);
1891       break;
1892 
1893     case relocInfo::opt_virtual_call_type:
1894       postponed |= clean_if_nmethod_is_unloaded(CompiledIC_at(&iter), is_alive, this);
1895       break;
1896 
1897     case relocInfo::static_call_type:
1898       postponed |= clean_if_nmethod_is_unloaded(compiledStaticCall_at(iter.reloc()), is_alive, this);
1899       break;
1900 
1901     case relocInfo::oop_type:
1902       if (!is_unloaded) {
1903         // Unload check
1904         oop_Relocation* r = iter.oop_reloc();
1905         // Traverse those oops directly embedded in the code.
1906         // Other oops (oop_index>0) are seen as part of scopes_oops.
1907         assert(1 == (r->oop_is_immediate()) +
1908                   (r->oop_addr() >= oops_begin() && r->oop_addr() < oops_end()),
1909               "oop must be found in exactly one place");
1910         if (r->oop_is_immediate() && r->oop_value() != NULL) {
1911           if (can_unload(is_alive, r->oop_addr(), unloading_occurred)) {
1912             is_unloaded = true;
1913           }
1914         }
1915       }
1916       break;
1917 
1918     }
1919   }
1920 
1921   if (is_unloaded) {
1922     return postponed;
1923   }
1924 
1925   // Scopes
1926   for (oop* p = oops_begin(); p < oops_end(); p++) {
1927     if (*p == Universe::non_oop_word())  continue;  // skip non-oops
1928     if (can_unload(is_alive, p, unloading_occurred)) {
1929       is_unloaded = true;
1930       break;
1931     }
1932   }
1933 
1934   if (is_unloaded) {
1935     return postponed;
1936   }
1937 
1938   // Ensure that all metadata is still alive
1939   verify_metadata_loaders(low_boundary, is_alive);
1940 
1941   return postponed;
1942 }
1943 
1944 void nmethod::do_unloading_parallel_postponed(BoolObjectClosure* is_alive, bool unloading_occurred) {
1945   ResourceMark rm;
1946 
1947   // Make sure the oop's ready to receive visitors
1948   assert(!is_zombie(),
1949          "should not call follow on zombie nmethod");
1950 
1951   // If the method is not entrant then a JMP is plastered over the
1952   // first few bytes.  If an oop in the old code was there, that oop
1953   // should not get GC'd.  Skip the first few bytes of oops on
1954   // not-entrant methods.
1955   address low_boundary = verified_entry_point();
1956   if (is_not_entrant()) {
1957     low_boundary += NativeJump::instruction_size;
1958     // %%% Note:  On SPARC we patch only a 4-byte trap, not a full NativeJump.
1959     // (See comment above.)
1960   }
1961 
1962   RelocIterator iter(this, low_boundary);
1963   while(iter.next()) {
1964 
1965     switch (iter.type()) {
1966 
1967     case relocInfo::virtual_call_type:
1968       clean_if_nmethod_is_unloaded(CompiledIC_at(&iter), is_alive, this);
1969       break;
1970 
1971     case relocInfo::opt_virtual_call_type:
1972       clean_if_nmethod_is_unloaded(CompiledIC_at(&iter), is_alive, this);
1973       break;
1974 
1975     case relocInfo::static_call_type:
1976       clean_if_nmethod_is_unloaded(compiledStaticCall_at(iter.reloc()), is_alive, this);
1977       break;
1978     }
1979   }
1980 }
1981 
1982 #ifdef ASSERT
1983 
1984 class CheckClass : AllStatic {
1985   static BoolObjectClosure* _is_alive;
1986 
1987   // Check class_loader is alive for this bit of metadata.
1988   static void check_class(Metadata* md) {
1989     Klass* klass = NULL;
1990     if (md->is_klass()) {
1991       klass = ((Klass*)md);
1992     } else if (md->is_method()) {
1993       klass = ((Method*)md)->method_holder();
1994     } else if (md->is_methodData()) {
1995       klass = ((MethodData*)md)->method()->method_holder();
1996     } else {
1997       md->print();
1998       ShouldNotReachHere();
1999     }
2000     assert(klass->is_loader_alive(_is_alive), "must be alive");
2001   }
2002  public:
2003   static void do_check_class(BoolObjectClosure* is_alive, nmethod* nm) {
2004     assert(SafepointSynchronize::is_at_safepoint(), "this is only ok at safepoint");
2005     _is_alive = is_alive;
2006     nm->metadata_do(check_class);
2007   }
2008 };
2009 
2010 // This is called during a safepoint so can use static data
2011 BoolObjectClosure* CheckClass::_is_alive = NULL;
2012 #endif // ASSERT
2013 
2014 
2015 // Processing of oop references should have been sufficient to keep
2016 // all strong references alive.  Any weak references should have been
2017 // cleared as well.  Visit all the metadata and ensure that it's
2018 // really alive.
2019 void nmethod::verify_metadata_loaders(address low_boundary, BoolObjectClosure* is_alive) {
2020 #ifdef ASSERT
2021     RelocIterator iter(this, low_boundary);
2022     while (iter.next()) {
2023     // static_stub_Relocations may have dangling references to
2024     // Method*s so trim them out here.  Otherwise it looks like
2025     // compiled code is maintaining a link to dead metadata.
2026     address static_call_addr = NULL;
2027     if (iter.type() == relocInfo::opt_virtual_call_type) {
2028       CompiledIC* cic = CompiledIC_at(&iter);
2029       if (!cic->is_call_to_interpreted()) {
2030         static_call_addr = iter.addr();
2031       }
2032     } else if (iter.type() == relocInfo::static_call_type) {
2033       CompiledStaticCall* csc = compiledStaticCall_at(iter.reloc());
2034       if (!csc->is_call_to_interpreted()) {
2035         static_call_addr = iter.addr();
2036       }
2037     }
2038     if (static_call_addr != NULL) {
2039       RelocIterator sciter(this, low_boundary);
2040       while (sciter.next()) {
2041         if (sciter.type() == relocInfo::static_stub_type &&
2042             sciter.static_stub_reloc()->static_call() == static_call_addr) {
2043           sciter.static_stub_reloc()->clear_inline_cache();
2044         }
2045       }
2046     }
2047   }
2048   // Check that the metadata embedded in the nmethod is alive
2049   CheckClass::do_check_class(is_alive, this);
2050 #endif
2051 }
2052 
2053 
2054 // Iterate over metadata calling this function.   Used by RedefineClasses
2055 void nmethod::metadata_do(void f(Metadata*)) {
2056   address low_boundary = verified_entry_point();
2057   if (is_not_entrant()) {
2058     low_boundary += NativeJump::instruction_size;
2059     // %%% Note:  On SPARC we patch only a 4-byte trap, not a full NativeJump.
2060     // (See comment above.)
2061   }
2062   {
2063     // Visit all immediate references that are embedded in the instruction stream.
2064     RelocIterator iter(this, low_boundary);
2065     while (iter.next()) {
2066       if (iter.type() == relocInfo::metadata_type ) {
2067         metadata_Relocation* r = iter.metadata_reloc();
2068         // In this lmetadata, we must only follow those metadatas directly embedded in
2069         // the code.  Other metadatas (oop_index>0) are seen as part of
2070         // the metadata section below.
2071         assert(1 == (r->metadata_is_immediate()) +
2072                (r->metadata_addr() >= metadata_begin() && r->metadata_addr() < metadata_end()),
2073                "metadata must be found in exactly one place");
2074         if (r->metadata_is_immediate() && r->metadata_value() != NULL) {
2075           Metadata* md = r->metadata_value();
2076           if (md != _method) f(md);
2077         }
2078       } else if (iter.type() == relocInfo::virtual_call_type) {
2079         // Check compiledIC holders associated with this nmethod
2080         CompiledIC *ic = CompiledIC_at(&iter);
2081         if (ic->is_icholder_call()) {
2082           CompiledICHolder* cichk = ic->cached_icholder();
2083           f(cichk->holder_method());
2084           f(cichk->holder_klass());
2085         } else {
2086           Metadata* ic_oop = ic->cached_metadata();
2087           if (ic_oop != NULL) {
2088             f(ic_oop);
2089           }
2090         }
2091       }
2092     }
2093   }
2094 
2095   // Visit the metadata section
2096   for (Metadata** p = metadata_begin(); p < metadata_end(); p++) {
2097     if (*p == Universe::non_oop_word() || *p == NULL)  continue;  // skip non-oops
2098     Metadata* md = *p;
2099     f(md);
2100   }
2101 
2102   // Call function Method*, not embedded in these other places.
2103   if (_method != NULL) f(_method);
2104 }
2105 
2106 void nmethod::oops_do(OopClosure* f, bool allow_zombie) {
2107   // make sure the oops ready to receive visitors
2108   assert(allow_zombie || !is_zombie(), "should not call follow on zombie nmethod");
2109   assert(!is_unloaded(), "should not call follow on unloaded nmethod");
2110 
2111   // If the method is not entrant or zombie then a JMP is plastered over the
2112   // first few bytes.  If an oop in the old code was there, that oop
2113   // should not get GC'd.  Skip the first few bytes of oops on
2114   // not-entrant methods.
2115   address low_boundary = verified_entry_point();
2116   if (is_not_entrant()) {
2117     low_boundary += NativeJump::instruction_size;
2118     // %%% Note:  On SPARC we patch only a 4-byte trap, not a full NativeJump.
2119     // (See comment above.)
2120   }
2121 
2122   RelocIterator iter(this, low_boundary);
2123 
2124   while (iter.next()) {
2125     if (iter.type() == relocInfo::oop_type ) {
2126       oop_Relocation* r = iter.oop_reloc();
2127       // In this loop, we must only follow those oops directly embedded in
2128       // the code.  Other oops (oop_index>0) are seen as part of scopes_oops.
2129       assert(1 == (r->oop_is_immediate()) +
2130                    (r->oop_addr() >= oops_begin() && r->oop_addr() < oops_end()),
2131              "oop must be found in exactly one place");
2132       if (r->oop_is_immediate() && r->oop_value() != NULL) {
2133         f->do_oop(r->oop_addr());
2134       }
2135     }
2136   }
2137 
2138   // Scopes
2139   // This includes oop constants not inlined in the code stream.
2140   for (oop* p = oops_begin(); p < oops_end(); p++) {
2141     if (*p == Universe::non_oop_word())  continue;  // skip non-oops
2142     f->do_oop(p);
2143   }
2144 }
2145 
2146 #define NMETHOD_SENTINEL ((nmethod*)badAddress)
2147 
2148 nmethod* volatile nmethod::_oops_do_mark_nmethods;
2149 
2150 // An nmethod is "marked" if its _mark_link is set non-null.
2151 // Even if it is the end of the linked list, it will have a non-null link value,
2152 // as long as it is on the list.
2153 // This code must be MP safe, because it is used from parallel GC passes.
2154 bool nmethod::test_set_oops_do_mark() {
2155   assert(nmethod::oops_do_marking_is_active(), "oops_do_marking_prologue must be called");
2156   nmethod* observed_mark_link = _oops_do_mark_link;
2157   if (observed_mark_link == NULL) {
2158     // Claim this nmethod for this thread to mark.
2159     observed_mark_link = (nmethod*)
2160       Atomic::cmpxchg_ptr(NMETHOD_SENTINEL, &_oops_do_mark_link, NULL);
2161     if (observed_mark_link == NULL) {
2162 
2163       // Atomically append this nmethod (now claimed) to the head of the list:
2164       nmethod* observed_mark_nmethods = _oops_do_mark_nmethods;
2165       for (;;) {
2166         nmethod* required_mark_nmethods = observed_mark_nmethods;
2167         _oops_do_mark_link = required_mark_nmethods;
2168         observed_mark_nmethods = (nmethod*)
2169           Atomic::cmpxchg_ptr(this, &_oops_do_mark_nmethods, required_mark_nmethods);
2170         if (observed_mark_nmethods == required_mark_nmethods)
2171           break;
2172       }
2173       // Mark was clear when we first saw this guy.
2174       NOT_PRODUCT(if (TraceScavenge)  print_on(tty, "oops_do, mark"));
2175       return false;
2176     }
2177   }
2178   // On fall through, another racing thread marked this nmethod before we did.
2179   return true;
2180 }
2181 
2182 void nmethod::oops_do_marking_prologue() {
2183   NOT_PRODUCT(if (TraceScavenge)  tty->print_cr("[oops_do_marking_prologue"));
2184   assert(_oops_do_mark_nmethods == NULL, "must not call oops_do_marking_prologue twice in a row");
2185   // We use cmpxchg_ptr instead of regular assignment here because the user
2186   // may fork a bunch of threads, and we need them all to see the same state.
2187   void* observed = Atomic::cmpxchg_ptr(NMETHOD_SENTINEL, &_oops_do_mark_nmethods, NULL);
2188   guarantee(observed == NULL, "no races in this sequential code");
2189 }
2190 
2191 void nmethod::oops_do_marking_epilogue() {
2192   assert(_oops_do_mark_nmethods != NULL, "must not call oops_do_marking_epilogue twice in a row");
2193   nmethod* cur = _oops_do_mark_nmethods;
2194   while (cur != NMETHOD_SENTINEL) {
2195     assert(cur != NULL, "not NULL-terminated");
2196     nmethod* next = cur->_oops_do_mark_link;
2197     cur->_oops_do_mark_link = NULL;
2198     cur->verify_oop_relocations();
2199     NOT_PRODUCT(if (TraceScavenge)  cur->print_on(tty, "oops_do, unmark"));
2200     cur = next;
2201   }
2202   void* required = _oops_do_mark_nmethods;
2203   void* observed = Atomic::cmpxchg_ptr(NULL, &_oops_do_mark_nmethods, required);
2204   guarantee(observed == required, "no races in this sequential code");
2205   NOT_PRODUCT(if (TraceScavenge)  tty->print_cr("oops_do_marking_epilogue]"));
2206 }
2207 
2208 class DetectScavengeRoot: public OopClosure {
2209   bool     _detected_scavenge_root;
2210 public:
2211   DetectScavengeRoot() : _detected_scavenge_root(false)
2212   { NOT_PRODUCT(_print_nm = NULL); }
2213   bool detected_scavenge_root() { return _detected_scavenge_root; }
2214   virtual void do_oop(oop* p) {
2215     if ((*p) != NULL && (*p)->is_scavengable()) {
2216       NOT_PRODUCT(maybe_print(p));
2217       _detected_scavenge_root = true;
2218     }
2219   }
2220   virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
2221 
2222 #ifndef PRODUCT
2223   nmethod* _print_nm;
2224   void maybe_print(oop* p) {
2225     if (_print_nm == NULL)  return;
2226     if (!_detected_scavenge_root)  _print_nm->print_on(tty, "new scavenge root");
2227     tty->print_cr(""PTR_FORMAT"[offset=%d] detected scavengable oop "PTR_FORMAT" (found at "PTR_FORMAT")",
2228                   _print_nm, (int)((intptr_t)p - (intptr_t)_print_nm),
2229                   (void *)(*p), (intptr_t)p);
2230     (*p)->print();
2231   }
2232 #endif //PRODUCT
2233 };
2234 
2235 bool nmethod::detect_scavenge_root_oops() {
2236   DetectScavengeRoot detect_scavenge_root;
2237   NOT_PRODUCT(if (TraceScavenge)  detect_scavenge_root._print_nm = this);
2238   oops_do(&detect_scavenge_root);
2239   return detect_scavenge_root.detected_scavenge_root();
2240 }
2241 
2242 // Method that knows how to preserve outgoing arguments at call. This method must be
2243 // called with a frame corresponding to a Java invoke
2244 void nmethod::preserve_callee_argument_oops(frame fr, const RegisterMap *reg_map, OopClosure* f) {
2245 #ifndef SHARK
2246   if (!method()->is_native()) {
2247     SimpleScopeDesc ssd(this, fr.pc());
2248     Bytecode_invoke call(ssd.method(), ssd.bci());
2249     bool has_receiver = call.has_receiver();
2250     bool has_appendix = call.has_appendix();
2251     Symbol* signature = call.signature();
2252     fr.oops_compiled_arguments_do(signature, has_receiver, has_appendix, reg_map, f);
2253   }
2254 #endif // !SHARK
2255 }
2256 
2257 
2258 oop nmethod::embeddedOop_at(u_char* p) {
2259   RelocIterator iter(this, p, p + 1);
2260   while (iter.next())
2261     if (iter.type() == relocInfo::oop_type) {
2262       return iter.oop_reloc()->oop_value();
2263     }
2264   return NULL;
2265 }
2266 
2267 
2268 inline bool includes(void* p, void* from, void* to) {
2269   return from <= p && p < to;
2270 }
2271 
2272 
2273 void nmethod::copy_scopes_pcs(PcDesc* pcs, int count) {
2274   assert(count >= 2, "must be sentinel values, at least");
2275 
2276 #ifdef ASSERT
2277   // must be sorted and unique; we do a binary search in find_pc_desc()
2278   int prev_offset = pcs[0].pc_offset();
2279   assert(prev_offset == PcDesc::lower_offset_limit,
2280          "must start with a sentinel");
2281   for (int i = 1; i < count; i++) {
2282     int this_offset = pcs[i].pc_offset();
2283     assert(this_offset > prev_offset, "offsets must be sorted");
2284     prev_offset = this_offset;
2285   }
2286   assert(prev_offset == PcDesc::upper_offset_limit,
2287          "must end with a sentinel");
2288 #endif //ASSERT
2289 
2290   // Search for MethodHandle invokes and tag the nmethod.
2291   for (int i = 0; i < count; i++) {
2292     if (pcs[i].is_method_handle_invoke()) {
2293       set_has_method_handle_invokes(true);
2294       break;
2295     }
2296   }
2297   assert(has_method_handle_invokes() == (_deoptimize_mh_offset != -1), "must have deopt mh handler");
2298 
2299   int size = count * sizeof(PcDesc);
2300   assert(scopes_pcs_size() >= size, "oob");
2301   memcpy(scopes_pcs_begin(), pcs, size);
2302 
2303   // Adjust the final sentinel downward.
2304   PcDesc* last_pc = &scopes_pcs_begin()[count-1];
2305   assert(last_pc->pc_offset() == PcDesc::upper_offset_limit, "sanity");
2306   last_pc->set_pc_offset(content_size() + 1);
2307   for (; last_pc + 1 < scopes_pcs_end(); last_pc += 1) {
2308     // Fill any rounding gaps with copies of the last record.
2309     last_pc[1] = last_pc[0];
2310   }
2311   // The following assert could fail if sizeof(PcDesc) is not
2312   // an integral multiple of oopSize (the rounding term).
2313   // If it fails, change the logic to always allocate a multiple
2314   // of sizeof(PcDesc), and fill unused words with copies of *last_pc.
2315   assert(last_pc + 1 == scopes_pcs_end(), "must match exactly");
2316 }
2317 
2318 void nmethod::copy_scopes_data(u_char* buffer, int size) {
2319   assert(scopes_data_size() >= size, "oob");
2320   memcpy(scopes_data_begin(), buffer, size);
2321 }
2322 
2323 
2324 #ifdef ASSERT
2325 static PcDesc* linear_search(nmethod* nm, int pc_offset, bool approximate) {
2326   PcDesc* lower = nm->scopes_pcs_begin();
2327   PcDesc* upper = nm->scopes_pcs_end();
2328   lower += 1; // exclude initial sentinel
2329   PcDesc* res = NULL;
2330   for (PcDesc* p = lower; p < upper; p++) {
2331     NOT_PRODUCT(--nmethod_stats.pc_desc_tests);  // don't count this call to match_desc
2332     if (match_desc(p, pc_offset, approximate)) {
2333       if (res == NULL)
2334         res = p;
2335       else
2336         res = (PcDesc*) badAddress;
2337     }
2338   }
2339   return res;
2340 }
2341 #endif
2342 
2343 
2344 // Finds a PcDesc with real-pc equal to "pc"
2345 PcDesc* nmethod::find_pc_desc_internal(address pc, bool approximate) {
2346   address base_address = code_begin();
2347   if ((pc < base_address) ||
2348       (pc - base_address) >= (ptrdiff_t) PcDesc::upper_offset_limit) {
2349     return NULL;  // PC is wildly out of range
2350   }
2351   int pc_offset = (int) (pc - base_address);
2352 
2353   // Check the PcDesc cache if it contains the desired PcDesc
2354   // (This as an almost 100% hit rate.)
2355   PcDesc* res = _pc_desc_cache.find_pc_desc(pc_offset, approximate);
2356   if (res != NULL) {
2357     assert(res == linear_search(this, pc_offset, approximate), "cache ok");
2358     return res;
2359   }
2360 
2361   // Fallback algorithm: quasi-linear search for the PcDesc
2362   // Find the last pc_offset less than the given offset.
2363   // The successor must be the required match, if there is a match at all.
2364   // (Use a fixed radix to avoid expensive affine pointer arithmetic.)
2365   PcDesc* lower = scopes_pcs_begin();
2366   PcDesc* upper = scopes_pcs_end();
2367   upper -= 1; // exclude final sentinel
2368   if (lower >= upper)  return NULL;  // native method; no PcDescs at all
2369 
2370 #define assert_LU_OK \
2371   /* invariant on lower..upper during the following search: */ \
2372   assert(lower->pc_offset() <  pc_offset, "sanity"); \
2373   assert(upper->pc_offset() >= pc_offset, "sanity")
2374   assert_LU_OK;
2375 
2376   // Use the last successful return as a split point.
2377   PcDesc* mid = _pc_desc_cache.last_pc_desc();
2378   NOT_PRODUCT(++nmethod_stats.pc_desc_searches);
2379   if (mid->pc_offset() < pc_offset) {
2380     lower = mid;
2381   } else {
2382     upper = mid;
2383   }
2384 
2385   // Take giant steps at first (4096, then 256, then 16, then 1)
2386   const int LOG2_RADIX = 4 /*smaller steps in debug mode:*/ debug_only(-1);
2387   const int RADIX = (1 << LOG2_RADIX);
2388   for (int step = (1 << (LOG2_RADIX*3)); step > 1; step >>= LOG2_RADIX) {
2389     while ((mid = lower + step) < upper) {
2390       assert_LU_OK;
2391       NOT_PRODUCT(++nmethod_stats.pc_desc_searches);
2392       if (mid->pc_offset() < pc_offset) {
2393         lower = mid;
2394       } else {
2395         upper = mid;
2396         break;
2397       }
2398     }
2399     assert_LU_OK;
2400   }
2401 
2402   // Sneak up on the value with a linear search of length ~16.
2403   while (true) {
2404     assert_LU_OK;
2405     mid = lower + 1;
2406     NOT_PRODUCT(++nmethod_stats.pc_desc_searches);
2407     if (mid->pc_offset() < pc_offset) {
2408       lower = mid;
2409     } else {
2410       upper = mid;
2411       break;
2412     }
2413   }
2414 #undef assert_LU_OK
2415 
2416   if (match_desc(upper, pc_offset, approximate)) {
2417     assert(upper == linear_search(this, pc_offset, approximate), "search ok");
2418     _pc_desc_cache.add_pc_desc(upper);
2419     return upper;
2420   } else {
2421     assert(NULL == linear_search(this, pc_offset, approximate), "search ok");
2422     return NULL;
2423   }
2424 }
2425 
2426 
2427 void nmethod::check_all_dependencies(DepChange& changes) {
2428   // Checked dependencies are allocated into this ResourceMark
2429   ResourceMark rm;
2430 
2431   // Turn off dependency tracing while actually testing dependencies.
2432   NOT_PRODUCT( FlagSetting fs(TraceDependencies, false) );
2433 
2434   typedef ResourceHashtable<DependencySignature, int, &DependencySignature::hash,
2435                             &DependencySignature::equals, 11027> DepTable;
2436 
2437   DepTable* table = new DepTable();
2438 
2439   // Iterate over live nmethods and check dependencies of all nmethods that are not
2440   // marked for deoptimization. A particular dependency is only checked once.
2441   NMethodIterator iter;
2442   while(iter.next()) {
2443     nmethod* nm = iter.method();
2444     // Only notify for live nmethods
2445     if (nm->is_alive() && !nm->is_marked_for_deoptimization()) {
2446       for (Dependencies::DepStream deps(nm); deps.next(); ) {
2447         // Construct abstraction of a dependency.
2448         DependencySignature* current_sig = new DependencySignature(deps);
2449 
2450         // Determine if dependency is already checked. table->put(...) returns
2451         // 'true' if the dependency is added (i.e., was not in the hashtable).
2452         if (table->put(*current_sig, 1)) {
2453           if (deps.check_dependency() != NULL) {
2454             // Dependency checking failed. Print out information about the failed
2455             // dependency and finally fail with an assert. We can fail here, since
2456             // dependency checking is never done in a product build.
2457             changes.print();
2458             nm->print();
2459             nm->print_dependencies();
2460             assert(false, "Should have been marked for deoptimization");
2461           }
2462         }
2463       }
2464     }
2465   }
2466 }
2467 
2468 bool nmethod::check_dependency_on(DepChange& changes) {
2469   // What has happened:
2470   // 1) a new class dependee has been added
2471   // 2) dependee and all its super classes have been marked
2472   bool found_check = false;  // set true if we are upset
2473   for (Dependencies::DepStream deps(this); deps.next(); ) {
2474     // Evaluate only relevant dependencies.
2475     if (deps.spot_check_dependency_at(changes) != NULL) {
2476       found_check = true;
2477       NOT_DEBUG(break);
2478     }
2479   }
2480   return found_check;
2481 }
2482 
2483 bool nmethod::is_evol_dependent_on(Klass* dependee) {
2484   InstanceKlass *dependee_ik = InstanceKlass::cast(dependee);
2485   Array<Method*>* dependee_methods = dependee_ik->methods();
2486   for (Dependencies::DepStream deps(this); deps.next(); ) {
2487     if (deps.type() == Dependencies::evol_method) {
2488       Method* method = deps.method_argument(0);
2489       for (int j = 0; j < dependee_methods->length(); j++) {
2490         if (dependee_methods->at(j) == method) {
2491           // RC_TRACE macro has an embedded ResourceMark
2492           RC_TRACE(0x01000000,
2493             ("Found evol dependency of nmethod %s.%s(%s) compile_id=%d on method %s.%s(%s)",
2494             _method->method_holder()->external_name(),
2495             _method->name()->as_C_string(),
2496             _method->signature()->as_C_string(), compile_id(),
2497             method->method_holder()->external_name(),
2498             method->name()->as_C_string(),
2499             method->signature()->as_C_string()));
2500           if (TraceDependencies || LogCompilation)
2501             deps.log_dependency(dependee);
2502           return true;
2503         }
2504       }
2505     }
2506   }
2507   return false;
2508 }
2509 
2510 // Called from mark_for_deoptimization, when dependee is invalidated.
2511 bool nmethod::is_dependent_on_method(Method* dependee) {
2512   for (Dependencies::DepStream deps(this); deps.next(); ) {
2513     if (deps.type() != Dependencies::evol_method)
2514       continue;
2515     Method* method = deps.method_argument(0);
2516     if (method == dependee) return true;
2517   }
2518   return false;
2519 }
2520 
2521 
2522 bool nmethod::is_patchable_at(address instr_addr) {
2523   assert(insts_contains(instr_addr), "wrong nmethod used");
2524   if (is_zombie()) {
2525     // a zombie may never be patched
2526     return false;
2527   }
2528   return true;
2529 }
2530 
2531 
2532 address nmethod::continuation_for_implicit_exception(address pc) {
2533   // Exception happened outside inline-cache check code => we are inside
2534   // an active nmethod => use cpc to determine a return address
2535   int exception_offset = pc - code_begin();
2536   int cont_offset = ImplicitExceptionTable(this).at( exception_offset );
2537 #ifdef ASSERT
2538   if (cont_offset == 0) {
2539     Thread* thread = ThreadLocalStorage::get_thread_slow();
2540     ResetNoHandleMark rnm; // Might be called from LEAF/QUICK ENTRY
2541     HandleMark hm(thread);
2542     ResourceMark rm(thread);
2543     CodeBlob* cb = CodeCache::find_blob(pc);
2544     assert(cb != NULL && cb == this, "");
2545     tty->print_cr("implicit exception happened at " INTPTR_FORMAT, pc);
2546     print();
2547     method()->print_codes();
2548     print_code();
2549     print_pcs();
2550   }
2551 #endif
2552   if (cont_offset == 0) {
2553     // Let the normal error handling report the exception
2554     return NULL;
2555   }
2556   return code_begin() + cont_offset;
2557 }
2558 
2559 
2560 
2561 void nmethod_init() {
2562   // make sure you didn't forget to adjust the filler fields
2563   assert(sizeof(nmethod) % oopSize == 0, "nmethod size must be multiple of a word");
2564 }
2565 
2566 
2567 //-------------------------------------------------------------------------------------------
2568 
2569 
2570 // QQQ might we make this work from a frame??
2571 nmethodLocker::nmethodLocker(address pc) {
2572   CodeBlob* cb = CodeCache::find_blob(pc);
2573   guarantee(cb != NULL && cb->is_nmethod(), "bad pc for a nmethod found");
2574   _nm = (nmethod*)cb;
2575   lock_nmethod(_nm);
2576 }
2577 
2578 // Only JvmtiDeferredEvent::compiled_method_unload_event()
2579 // should pass zombie_ok == true.
2580 void nmethodLocker::lock_nmethod(nmethod* nm, bool zombie_ok) {
2581   if (nm == NULL)  return;
2582   Atomic::inc(&nm->_lock_count);
2583   assert(zombie_ok || !nm->is_zombie(), "cannot lock a zombie method");
2584 }
2585 
2586 void nmethodLocker::unlock_nmethod(nmethod* nm) {
2587   if (nm == NULL)  return;
2588   Atomic::dec(&nm->_lock_count);
2589   assert(nm->_lock_count >= 0, "unmatched nmethod lock/unlock");
2590 }
2591 
2592 
2593 // -----------------------------------------------------------------------------
2594 // nmethod::get_deopt_original_pc
2595 //
2596 // Return the original PC for the given PC if:
2597 // (a) the given PC belongs to a nmethod and
2598 // (b) it is a deopt PC
2599 address nmethod::get_deopt_original_pc(const frame* fr) {
2600   if (fr->cb() == NULL)  return NULL;
2601 
2602   nmethod* nm = fr->cb()->as_nmethod_or_null();
2603   if (nm != NULL && nm->is_deopt_pc(fr->pc()))
2604     return nm->get_original_pc(fr);
2605 
2606   return NULL;
2607 }
2608 
2609 
2610 // -----------------------------------------------------------------------------
2611 // MethodHandle
2612 
2613 bool nmethod::is_method_handle_return(address return_pc) {
2614   if (!has_method_handle_invokes())  return false;
2615   PcDesc* pd = pc_desc_at(return_pc);
2616   if (pd == NULL)
2617     return false;
2618   return pd->is_method_handle_invoke();
2619 }
2620 
2621 
2622 // -----------------------------------------------------------------------------
2623 // Verification
2624 
2625 class VerifyOopsClosure: public OopClosure {
2626   nmethod* _nm;
2627   bool     _ok;
2628 public:
2629   VerifyOopsClosure(nmethod* nm) : _nm(nm), _ok(true) { }
2630   bool ok() { return _ok; }
2631   virtual void do_oop(oop* p) {
2632     if ((*p) == NULL || (*p)->is_oop())  return;
2633     if (_ok) {
2634       _nm->print_nmethod(true);
2635       _ok = false;
2636     }
2637     tty->print_cr("*** non-oop "PTR_FORMAT" found at "PTR_FORMAT" (offset %d)",
2638                   (void *)(*p), (intptr_t)p, (int)((intptr_t)p - (intptr_t)_nm));
2639   }
2640   virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
2641 };
2642 
2643 void nmethod::verify() {
2644 
2645   // Hmm. OSR methods can be deopted but not marked as zombie or not_entrant
2646   // seems odd.
2647 
2648   if( is_zombie() || is_not_entrant() )
2649     return;
2650 
2651   // Make sure all the entry points are correctly aligned for patching.
2652   NativeJump::check_verified_entry_alignment(entry_point(), verified_entry_point());
2653 
2654   // assert(method()->is_oop(), "must be valid");
2655 
2656   ResourceMark rm;
2657 
2658   if (!CodeCache::contains(this)) {
2659     fatal(err_msg("nmethod at " INTPTR_FORMAT " not in zone", this));
2660   }
2661 
2662   if(is_native_method() )
2663     return;
2664 
2665   nmethod* nm = CodeCache::find_nmethod(verified_entry_point());
2666   if (nm != this) {
2667     fatal(err_msg("findNMethod did not find this nmethod (" INTPTR_FORMAT ")",
2668                   this));
2669   }
2670 
2671   for (PcDesc* p = scopes_pcs_begin(); p < scopes_pcs_end(); p++) {
2672     if (! p->verify(this)) {
2673       tty->print_cr("\t\tin nmethod at " INTPTR_FORMAT " (pcs)", this);
2674     }
2675   }
2676 
2677   VerifyOopsClosure voc(this);
2678   oops_do(&voc);
2679   assert(voc.ok(), "embedded oops must be OK");
2680   verify_scavenge_root_oops();
2681 
2682   verify_scopes();
2683 }
2684 
2685 
2686 void nmethod::verify_interrupt_point(address call_site) {
2687   // Verify IC only when nmethod installation is finished.
2688   bool is_installed = (method()->code() == this) // nmethod is in state 'in_use' and installed
2689                       || !this->is_in_use();     // nmethod is installed, but not in 'in_use' state
2690   if (is_installed) {
2691     Thread *cur = Thread::current();
2692     if (CompiledIC_lock->owner() == cur ||
2693         ((cur->is_VM_thread() || cur->is_ConcurrentGC_thread()) &&
2694          SafepointSynchronize::is_at_safepoint())) {
2695       CompiledIC_at(this, call_site);
2696       CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops());
2697     } else {
2698       MutexLocker ml_verify (CompiledIC_lock);
2699       CompiledIC_at(this, call_site);
2700     }
2701   }
2702 
2703   PcDesc* pd = pc_desc_at(nativeCall_at(call_site)->return_address());
2704   assert(pd != NULL, "PcDesc must exist");
2705   for (ScopeDesc* sd = new ScopeDesc(this, pd->scope_decode_offset(),
2706                                      pd->obj_decode_offset(), pd->should_reexecute(),
2707                                      pd->return_oop());
2708        !sd->is_top(); sd = sd->sender()) {
2709     sd->verify();
2710   }
2711 }
2712 
2713 void nmethod::verify_scopes() {
2714   if( !method() ) return;       // Runtime stubs have no scope
2715   if (method()->is_native()) return; // Ignore stub methods.
2716   // iterate through all interrupt point
2717   // and verify the debug information is valid.
2718   RelocIterator iter((nmethod*)this);
2719   while (iter.next()) {
2720     address stub = NULL;
2721     switch (iter.type()) {
2722       case relocInfo::virtual_call_type:
2723         verify_interrupt_point(iter.addr());
2724         break;
2725       case relocInfo::opt_virtual_call_type:
2726         stub = iter.opt_virtual_call_reloc()->static_stub();
2727         verify_interrupt_point(iter.addr());
2728         break;
2729       case relocInfo::static_call_type:
2730         stub = iter.static_call_reloc()->static_stub();
2731         //verify_interrupt_point(iter.addr());
2732         break;
2733       case relocInfo::runtime_call_type:
2734         address destination = iter.reloc()->value();
2735         // Right now there is no way to find out which entries support
2736         // an interrupt point.  It would be nice if we had this
2737         // information in a table.
2738         break;
2739     }
2740     assert(stub == NULL || stub_contains(stub), "static call stub outside stub section");
2741   }
2742 }
2743 
2744 
2745 // -----------------------------------------------------------------------------
2746 // Non-product code
2747 #ifndef PRODUCT
2748 
2749 class DebugScavengeRoot: public OopClosure {
2750   nmethod* _nm;
2751   bool     _ok;
2752 public:
2753   DebugScavengeRoot(nmethod* nm) : _nm(nm), _ok(true) { }
2754   bool ok() { return _ok; }
2755   virtual void do_oop(oop* p) {
2756     if ((*p) == NULL || !(*p)->is_scavengable())  return;
2757     if (_ok) {
2758       _nm->print_nmethod(true);
2759       _ok = false;
2760     }
2761     tty->print_cr("*** scavengable oop "PTR_FORMAT" found at "PTR_FORMAT" (offset %d)",
2762                   (void *)(*p), (intptr_t)p, (int)((intptr_t)p - (intptr_t)_nm));
2763     (*p)->print();
2764   }
2765   virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
2766 };
2767 
2768 void nmethod::verify_scavenge_root_oops() {
2769   if (UseG1GC) {
2770     return;
2771   }
2772 
2773   if (!on_scavenge_root_list()) {
2774     // Actually look inside, to verify the claim that it's clean.
2775     DebugScavengeRoot debug_scavenge_root(this);
2776     oops_do(&debug_scavenge_root);
2777     if (!debug_scavenge_root.ok())
2778       fatal("found an unadvertised bad scavengable oop in the code cache");
2779   }
2780   assert(scavenge_root_not_marked(), "");
2781 }
2782 
2783 #endif // PRODUCT
2784 
2785 // Printing operations
2786 
2787 void nmethod::print() const {
2788   ResourceMark rm;
2789   ttyLocker ttyl;   // keep the following output all in one block
2790 
2791   tty->print("Compiled method ");
2792 
2793   if (is_compiled_by_c1()) {
2794     tty->print("(c1) ");
2795   } else if (is_compiled_by_c2()) {
2796     tty->print("(c2) ");
2797   } else if (is_compiled_by_shark()) {
2798     tty->print("(shark) ");
2799   } else {
2800     tty->print("(nm) ");
2801   }
2802 
2803   print_on(tty, NULL);
2804 
2805   if (WizardMode) {
2806     tty->print("((nmethod*) "INTPTR_FORMAT ") ", this);
2807     tty->print(" for method " INTPTR_FORMAT , (address)method());
2808     tty->print(" { ");
2809     if (is_in_use())      tty->print("in_use ");
2810     if (is_not_entrant()) tty->print("not_entrant ");
2811     if (is_zombie())      tty->print("zombie ");
2812     if (is_unloaded())    tty->print("unloaded ");
2813     if (on_scavenge_root_list())  tty->print("scavenge_root ");
2814     tty->print_cr("}:");
2815   }
2816   if (size              () > 0) tty->print_cr(" total in heap  [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2817                                               (address)this,
2818                                               (address)this + size(),
2819                                               size());
2820   if (relocation_size   () > 0) tty->print_cr(" relocation     [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2821                                               relocation_begin(),
2822                                               relocation_end(),
2823                                               relocation_size());
2824   if (consts_size       () > 0) tty->print_cr(" constants      [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2825                                               consts_begin(),
2826                                               consts_end(),
2827                                               consts_size());
2828   if (insts_size        () > 0) tty->print_cr(" main code      [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2829                                               insts_begin(),
2830                                               insts_end(),
2831                                               insts_size());
2832   if (stub_size         () > 0) tty->print_cr(" stub code      [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2833                                               stub_begin(),
2834                                               stub_end(),
2835                                               stub_size());
2836   if (oops_size         () > 0) tty->print_cr(" oops           [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2837                                               oops_begin(),
2838                                               oops_end(),
2839                                               oops_size());
2840   if (metadata_size      () > 0) tty->print_cr(" metadata       [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2841                                               metadata_begin(),
2842                                               metadata_end(),
2843                                               metadata_size());
2844   if (scopes_data_size  () > 0) tty->print_cr(" scopes data    [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2845                                               scopes_data_begin(),
2846                                               scopes_data_end(),
2847                                               scopes_data_size());
2848   if (scopes_pcs_size   () > 0) tty->print_cr(" scopes pcs     [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2849                                               scopes_pcs_begin(),
2850                                               scopes_pcs_end(),
2851                                               scopes_pcs_size());
2852   if (dependencies_size () > 0) tty->print_cr(" dependencies   [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2853                                               dependencies_begin(),
2854                                               dependencies_end(),
2855                                               dependencies_size());
2856   if (handler_table_size() > 0) tty->print_cr(" handler table  [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2857                                               handler_table_begin(),
2858                                               handler_table_end(),
2859                                               handler_table_size());
2860   if (nul_chk_table_size() > 0) tty->print_cr(" nul chk table  [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2861                                               nul_chk_table_begin(),
2862                                               nul_chk_table_end(),
2863                                               nul_chk_table_size());
2864 }
2865 
2866 void nmethod::print_code() {
2867   HandleMark hm;
2868   ResourceMark m;
2869   Disassembler::decode(this);
2870 }
2871 
2872 
2873 #ifndef PRODUCT
2874 
2875 void nmethod::print_scopes() {
2876   // Find the first pc desc for all scopes in the code and print it.
2877   ResourceMark rm;
2878   for (PcDesc* p = scopes_pcs_begin(); p < scopes_pcs_end(); p++) {
2879     if (p->scope_decode_offset() == DebugInformationRecorder::serialized_null)
2880       continue;
2881 
2882     ScopeDesc* sd = scope_desc_at(p->real_pc(this));
2883     sd->print_on(tty, p);
2884   }
2885 }
2886 
2887 void nmethod::print_dependencies() {
2888   ResourceMark rm;
2889   ttyLocker ttyl;   // keep the following output all in one block
2890   tty->print_cr("Dependencies:");
2891   for (Dependencies::DepStream deps(this); deps.next(); ) {
2892     deps.print_dependency();
2893     Klass* ctxk = deps.context_type();
2894     if (ctxk != NULL) {
2895       if (ctxk->oop_is_instance() && ((InstanceKlass*)ctxk)->is_dependent_nmethod(this)) {
2896         tty->print_cr("   [nmethod<=klass]%s", ctxk->external_name());
2897       }
2898     }
2899     deps.log_dependency();  // put it into the xml log also
2900   }
2901 }
2902 
2903 
2904 void nmethod::print_relocations() {
2905   ResourceMark m;       // in case methods get printed via the debugger
2906   tty->print_cr("relocations:");
2907   RelocIterator iter(this);
2908   iter.print();
2909   if (UseRelocIndex) {
2910     jint* index_end   = (jint*)relocation_end() - 1;
2911     jint  index_size  = *index_end;
2912     jint* index_start = (jint*)( (address)index_end - index_size );
2913     tty->print_cr("    index @" INTPTR_FORMAT ": index_size=%d", index_start, index_size);
2914     if (index_size > 0) {
2915       jint* ip;
2916       for (ip = index_start; ip+2 <= index_end; ip += 2)
2917         tty->print_cr("  (%d %d) addr=" INTPTR_FORMAT " @" INTPTR_FORMAT,
2918                       ip[0],
2919                       ip[1],
2920                       header_end()+ip[0],
2921                       relocation_begin()-1+ip[1]);
2922       for (; ip < index_end; ip++)
2923         tty->print_cr("  (%d ?)", ip[0]);
2924       tty->print_cr("          @" INTPTR_FORMAT ": index_size=%d", ip, *ip);
2925       ip++;
2926       tty->print_cr("reloc_end @" INTPTR_FORMAT ":", ip);
2927     }
2928   }
2929 }
2930 
2931 
2932 void nmethod::print_pcs() {
2933   ResourceMark m;       // in case methods get printed via debugger
2934   tty->print_cr("pc-bytecode offsets:");
2935   for (PcDesc* p = scopes_pcs_begin(); p < scopes_pcs_end(); p++) {
2936     p->print(this);
2937   }
2938 }
2939 
2940 #endif // PRODUCT
2941 
2942 const char* nmethod::reloc_string_for(u_char* begin, u_char* end) {
2943   RelocIterator iter(this, begin, end);
2944   bool have_one = false;
2945   while (iter.next()) {
2946     have_one = true;
2947     switch (iter.type()) {
2948         case relocInfo::none:                  return "no_reloc";
2949         case relocInfo::oop_type: {
2950           stringStream st;
2951           oop_Relocation* r = iter.oop_reloc();
2952           oop obj = r->oop_value();
2953           st.print("oop(");
2954           if (obj == NULL) st.print("NULL");
2955           else obj->print_value_on(&st);
2956           st.print(")");
2957           return st.as_string();
2958         }
2959         case relocInfo::metadata_type: {
2960           stringStream st;
2961           metadata_Relocation* r = iter.metadata_reloc();
2962           Metadata* obj = r->metadata_value();
2963           st.print("metadata(");
2964           if (obj == NULL) st.print("NULL");
2965           else obj->print_value_on(&st);
2966           st.print(")");
2967           return st.as_string();
2968         }
2969         case relocInfo::virtual_call_type:     return "virtual_call";
2970         case relocInfo::opt_virtual_call_type: return "optimized virtual_call";
2971         case relocInfo::static_call_type:      return "static_call";
2972         case relocInfo::static_stub_type:      return "static_stub";
2973         case relocInfo::runtime_call_type:     return "runtime_call";
2974         case relocInfo::external_word_type:    return "external_word";
2975         case relocInfo::internal_word_type:    return "internal_word";
2976         case relocInfo::section_word_type:     return "section_word";
2977         case relocInfo::poll_type:             return "poll";
2978         case relocInfo::poll_return_type:      return "poll_return";
2979         case relocInfo::type_mask:             return "type_bit_mask";
2980     }
2981   }
2982   return have_one ? "other" : NULL;
2983 }
2984 
2985 // Return a the last scope in (begin..end]
2986 ScopeDesc* nmethod::scope_desc_in(address begin, address end) {
2987   PcDesc* p = pc_desc_near(begin+1);
2988   if (p != NULL && p->real_pc(this) <= end) {
2989     return new ScopeDesc(this, p->scope_decode_offset(),
2990                          p->obj_decode_offset(), p->should_reexecute(),
2991                          p->return_oop());
2992   }
2993   return NULL;
2994 }
2995 
2996 void nmethod::print_nmethod_labels(outputStream* stream, address block_begin) const {
2997   if (block_begin == entry_point())             stream->print_cr("[Entry Point]");
2998   if (block_begin == verified_entry_point())    stream->print_cr("[Verified Entry Point]");
2999   if (block_begin == exception_begin())         stream->print_cr("[Exception Handler]");
3000   if (block_begin == stub_begin())              stream->print_cr("[Stub Code]");
3001   if (block_begin == deopt_handler_begin())     stream->print_cr("[Deopt Handler Code]");
3002 
3003   if (has_method_handle_invokes())
3004     if (block_begin == deopt_mh_handler_begin())  stream->print_cr("[Deopt MH Handler Code]");
3005 
3006   if (block_begin == consts_begin())            stream->print_cr("[Constants]");
3007 
3008   if (block_begin == entry_point()) {
3009     methodHandle m = method();
3010     if (m.not_null()) {
3011       stream->print("  # ");
3012       m->print_value_on(stream);
3013       stream->cr();
3014     }
3015     if (m.not_null() && !is_osr_method()) {
3016       ResourceMark rm;
3017       int sizeargs = m->size_of_parameters();
3018       BasicType* sig_bt = NEW_RESOURCE_ARRAY(BasicType, sizeargs);
3019       VMRegPair* regs   = NEW_RESOURCE_ARRAY(VMRegPair, sizeargs);
3020       {
3021         int sig_index = 0;
3022         if (!m->is_static())
3023           sig_bt[sig_index++] = T_OBJECT; // 'this'
3024         for (SignatureStream ss(m->signature()); !ss.at_return_type(); ss.next()) {
3025           BasicType t = ss.type();
3026           sig_bt[sig_index++] = t;
3027           if (type2size[t] == 2) {
3028             sig_bt[sig_index++] = T_VOID;
3029           } else {
3030             assert(type2size[t] == 1, "size is 1 or 2");
3031           }
3032         }
3033         assert(sig_index == sizeargs, "");
3034       }
3035       const char* spname = "sp"; // make arch-specific?
3036       intptr_t out_preserve = SharedRuntime::java_calling_convention(sig_bt, regs, sizeargs, false);
3037       int stack_slot_offset = this->frame_size() * wordSize;
3038       int tab1 = 14, tab2 = 24;
3039       int sig_index = 0;
3040       int arg_index = (m->is_static() ? 0 : -1);
3041       bool did_old_sp = false;
3042       for (SignatureStream ss(m->signature()); !ss.at_return_type(); ) {
3043         bool at_this = (arg_index == -1);
3044         bool at_old_sp = false;
3045         BasicType t = (at_this ? T_OBJECT : ss.type());
3046         assert(t == sig_bt[sig_index], "sigs in sync");
3047         if (at_this)
3048           stream->print("  # this: ");
3049         else
3050           stream->print("  # parm%d: ", arg_index);
3051         stream->move_to(tab1);
3052         VMReg fst = regs[sig_index].first();
3053         VMReg snd = regs[sig_index].second();
3054         if (fst->is_reg()) {
3055           stream->print("%s", fst->name());
3056           if (snd->is_valid())  {
3057             stream->print(":%s", snd->name());
3058           }
3059         } else if (fst->is_stack()) {
3060           int offset = fst->reg2stack() * VMRegImpl::stack_slot_size + stack_slot_offset;
3061           if (offset == stack_slot_offset)  at_old_sp = true;
3062           stream->print("[%s+0x%x]", spname, offset);
3063         } else {
3064           stream->print("reg%d:%d??", (int)(intptr_t)fst, (int)(intptr_t)snd);
3065         }
3066         stream->print(" ");
3067         stream->move_to(tab2);
3068         stream->print("= ");
3069         if (at_this) {
3070           m->method_holder()->print_value_on(stream);
3071         } else {
3072           bool did_name = false;
3073           if (!at_this && ss.is_object()) {
3074             Symbol* name = ss.as_symbol_or_null();
3075             if (name != NULL) {
3076               name->print_value_on(stream);
3077               did_name = true;
3078             }
3079           }
3080           if (!did_name)
3081             stream->print("%s", type2name(t));
3082         }
3083         if (at_old_sp) {
3084           stream->print("  (%s of caller)", spname);
3085           did_old_sp = true;
3086         }
3087         stream->cr();
3088         sig_index += type2size[t];
3089         arg_index += 1;
3090         if (!at_this)  ss.next();
3091       }
3092       if (!did_old_sp) {
3093         stream->print("  # ");
3094         stream->move_to(tab1);
3095         stream->print("[%s+0x%x]", spname, stack_slot_offset);
3096         stream->print("  (%s of caller)", spname);
3097         stream->cr();
3098       }
3099     }
3100   }
3101 }
3102 
3103 void nmethod::print_code_comment_on(outputStream* st, int column, u_char* begin, u_char* end) {
3104   // First, find an oopmap in (begin, end].
3105   // We use the odd half-closed interval so that oop maps and scope descs
3106   // which are tied to the byte after a call are printed with the call itself.
3107   address base = code_begin();
3108   OopMapSet* oms = oop_maps();
3109   if (oms != NULL) {
3110     for (int i = 0, imax = oms->size(); i < imax; i++) {
3111       OopMap* om = oms->at(i);
3112       address pc = base + om->offset();
3113       if (pc > begin) {
3114         if (pc <= end) {
3115           st->move_to(column);
3116           st->print("; ");
3117           om->print_on(st);
3118         }
3119         break;
3120       }
3121     }
3122   }
3123 
3124   // Print any debug info present at this pc.
3125   ScopeDesc* sd  = scope_desc_in(begin, end);
3126   if (sd != NULL) {
3127     st->move_to(column);
3128     if (sd->bci() == SynchronizationEntryBCI) {
3129       st->print(";*synchronization entry");
3130     } else {
3131       if (sd->method() == NULL) {
3132         st->print("method is NULL");
3133       } else if (sd->method()->is_native()) {
3134         st->print("method is native");
3135       } else {
3136         Bytecodes::Code bc = sd->method()->java_code_at(sd->bci());
3137         st->print(";*%s", Bytecodes::name(bc));
3138         switch (bc) {
3139         case Bytecodes::_invokevirtual:
3140         case Bytecodes::_invokespecial:
3141         case Bytecodes::_invokestatic:
3142         case Bytecodes::_invokeinterface:
3143           {
3144             Bytecode_invoke invoke(sd->method(), sd->bci());
3145             st->print(" ");
3146             if (invoke.name() != NULL)
3147               invoke.name()->print_symbol_on(st);
3148             else
3149               st->print("<UNKNOWN>");
3150             break;
3151           }
3152         case Bytecodes::_getfield:
3153         case Bytecodes::_putfield:
3154         case Bytecodes::_getstatic:
3155         case Bytecodes::_putstatic:
3156           {
3157             Bytecode_field field(sd->method(), sd->bci());
3158             st->print(" ");
3159             if (field.name() != NULL)
3160               field.name()->print_symbol_on(st);
3161             else
3162               st->print("<UNKNOWN>");
3163           }
3164         }
3165       }
3166     }
3167 
3168     // Print all scopes
3169     for (;sd != NULL; sd = sd->sender()) {
3170       st->move_to(column);
3171       st->print("; -");
3172       if (sd->method() == NULL) {
3173         st->print("method is NULL");
3174       } else {
3175         sd->method()->print_short_name(st);
3176       }
3177       int lineno = sd->method()->line_number_from_bci(sd->bci());
3178       if (lineno != -1) {
3179         st->print("@%d (line %d)", sd->bci(), lineno);
3180       } else {
3181         st->print("@%d", sd->bci());
3182       }
3183       st->cr();
3184     }
3185   }
3186 
3187   // Print relocation information
3188   const char* str = reloc_string_for(begin, end);
3189   if (str != NULL) {
3190     if (sd != NULL) st->cr();
3191     st->move_to(column);
3192     st->print(";   {%s}", str);
3193   }
3194   int cont_offset = ImplicitExceptionTable(this).at(begin - code_begin());
3195   if (cont_offset != 0) {
3196     st->move_to(column);
3197     st->print("; implicit exception: dispatches to " INTPTR_FORMAT, code_begin() + cont_offset);
3198   }
3199 
3200 }
3201 
3202 #ifndef PRODUCT
3203 
3204 void nmethod::print_value_on(outputStream* st) const {
3205   st->print("nmethod");
3206   print_on(st, NULL);
3207 }
3208 
3209 void nmethod::print_calls(outputStream* st) {
3210   RelocIterator iter(this);
3211   while (iter.next()) {
3212     switch (iter.type()) {
3213     case relocInfo::virtual_call_type:
3214     case relocInfo::opt_virtual_call_type: {
3215       VerifyMutexLocker mc(CompiledIC_lock);
3216       CompiledIC_at(&iter)->print();
3217       break;
3218     }
3219     case relocInfo::static_call_type:
3220       st->print_cr("Static call at " INTPTR_FORMAT, iter.reloc()->addr());
3221       compiledStaticCall_at(iter.reloc())->print();
3222       break;
3223     }
3224   }
3225 }
3226 
3227 void nmethod::print_handler_table() {
3228   ExceptionHandlerTable(this).print();
3229 }
3230 
3231 void nmethod::print_nul_chk_table() {
3232   ImplicitExceptionTable(this).print(code_begin());
3233 }
3234 
3235 void nmethod::print_statistics() {
3236   ttyLocker ttyl;
3237   if (xtty != NULL)  xtty->head("statistics type='nmethod'");
3238   nmethod_stats.print_native_nmethod_stats();
3239   nmethod_stats.print_nmethod_stats();
3240   DebugInformationRecorder::print_statistics();
3241   nmethod_stats.print_pc_stats();
3242   Dependencies::print_statistics();
3243   if (xtty != NULL)  xtty->tail("statistics");
3244 }
3245 
3246 #endif // PRODUCT