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