1 /*
   2  * Copyright (c) 1997, 2011, 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/methodDataOop.hpp"
  38 #include "prims/jvmtiRedefineClassesTrace.hpp"
  39 #include "prims/jvmtiImpl.hpp"
  40 #include "runtime/sharedRuntime.hpp"
  41 #include "runtime/sweeper.hpp"
  42 #include "utilities/dtrace.hpp"
  43 #include "utilities/events.hpp"
  44 #include "utilities/xmlstream.hpp"
  45 #ifdef SHARK
  46 #include "shark/sharkCompiler.hpp"
  47 #endif
  48 
  49 #ifdef DTRACE_ENABLED
  50 
  51 // Only bother with this argument setup if dtrace is available
  52 
  53 #ifndef USDT2
  54 HS_DTRACE_PROBE_DECL8(hotspot, compiled__method__load,
  55   const char*, int, const char*, int, const char*, int, void*, size_t);
  56 
  57 HS_DTRACE_PROBE_DECL6(hotspot, compiled__method__unload,
  58   char*, int, char*, int, char*, int);
  59 
  60 #define DTRACE_METHOD_UNLOAD_PROBE(method)                                \
  61   {                                                                       \
  62     methodOop m = (method);                                               \
  63     if (m != NULL) {                                                      \
  64       Symbol* klass_name = m->klass_name();                               \
  65       Symbol* name = m->name();                                           \
  66       Symbol* signature = m->signature();                                 \
  67       HS_DTRACE_PROBE6(hotspot, compiled__method__unload,                 \
  68         klass_name->bytes(), klass_name->utf8_length(),                   \
  69         name->bytes(), name->utf8_length(),                               \
  70         signature->bytes(), signature->utf8_length());                    \
  71     }                                                                     \
  72   }
  73 #else /* USDT2 */
  74 #define DTRACE_METHOD_UNLOAD_PROBE(method)                                \
  75   {                                                                       \
  76     methodOop m = (method);                                               \
  77     if (m != NULL) {                                                      \
  78       Symbol* klass_name = m->klass_name();                               \
  79       Symbol* name = m->name();                                           \
  80       Symbol* signature = m->signature();                                 \
  81       HOTSPOT_COMPILED_METHOD_UNLOAD(                                     \
  82         (char *) klass_name->bytes(), klass_name->utf8_length(),                   \
  83         (char *) name->bytes(), name->utf8_length(),                               \
  84         (char *) signature->bytes(), signature->utf8_length());                    \
  85     }                                                                     \
  86   }
  87 #endif /* USDT2 */
  88 
  89 #else //  ndef DTRACE_ENABLED
  90 
  91 #define DTRACE_METHOD_UNLOAD_PROBE(method)
  92 
  93 #endif
  94 
  95 bool nmethod::is_compiled_by_c1() const {
  96   if (compiler() == NULL || method() == NULL)  return false;  // can happen during debug printing
  97   if (is_native_method()) return false;
  98   return compiler()->is_c1();
  99 }
 100 bool nmethod::is_compiled_by_c2() const {
 101   if (compiler() == NULL || method() == NULL)  return false;  // can happen during debug printing
 102   if (is_native_method()) return false;
 103   return compiler()->is_c2();
 104 }
 105 bool nmethod::is_compiled_by_shark() const {
 106   if (is_native_method()) return false;
 107   assert(compiler() != NULL, "must be");
 108   return compiler()->is_shark();
 109 }
 110 
 111 
 112 
 113 //---------------------------------------------------------------------------------
 114 // NMethod statistics
 115 // They are printed under various flags, including:
 116 //   PrintC1Statistics, PrintOptoStatistics, LogVMOutput, and LogCompilation.
 117 // (In the latter two cases, they like other stats are printed to the log only.)
 118 
 119 #ifndef PRODUCT
 120 // These variables are put into one block to reduce relocations
 121 // and make it simpler to print from the debugger.
 122 static
 123 struct nmethod_stats_struct {
 124   int nmethod_count;
 125   int total_size;
 126   int relocation_size;
 127   int consts_size;
 128   int insts_size;
 129   int stub_size;
 130   int scopes_data_size;
 131   int scopes_pcs_size;
 132   int dependencies_size;
 133   int handler_table_size;
 134   int nul_chk_table_size;
 135   int oops_size;
 136 
 137   void note_nmethod(nmethod* nm) {
 138     nmethod_count += 1;
 139     total_size          += nm->size();
 140     relocation_size     += nm->relocation_size();
 141     consts_size         += nm->consts_size();
 142     insts_size          += nm->insts_size();
 143     stub_size           += nm->stub_size();
 144     oops_size           += nm->oops_size();
 145     scopes_data_size    += nm->scopes_data_size();
 146     scopes_pcs_size     += nm->scopes_pcs_size();
 147     dependencies_size   += nm->dependencies_size();
 148     handler_table_size  += nm->handler_table_size();
 149     nul_chk_table_size  += nm->nul_chk_table_size();
 150   }
 151   void print_nmethod_stats() {
 152     if (nmethod_count == 0)  return;
 153     tty->print_cr("Statistics for %d bytecoded nmethods:", nmethod_count);
 154     if (total_size != 0)          tty->print_cr(" total in heap  = %d", total_size);
 155     if (relocation_size != 0)     tty->print_cr(" relocation     = %d", relocation_size);
 156     if (consts_size != 0)         tty->print_cr(" constants      = %d", consts_size);
 157     if (insts_size != 0)          tty->print_cr(" main code      = %d", insts_size);
 158     if (stub_size != 0)           tty->print_cr(" stub code      = %d", stub_size);
 159     if (oops_size != 0)           tty->print_cr(" oops           = %d", oops_size);
 160     if (scopes_data_size != 0)    tty->print_cr(" scopes data    = %d", scopes_data_size);
 161     if (scopes_pcs_size != 0)     tty->print_cr(" scopes pcs     = %d", scopes_pcs_size);
 162     if (dependencies_size != 0)   tty->print_cr(" dependencies   = %d", dependencies_size);
 163     if (handler_table_size != 0)  tty->print_cr(" handler table  = %d", handler_table_size);
 164     if (nul_chk_table_size != 0)  tty->print_cr(" nul chk table  = %d", nul_chk_table_size);
 165   }
 166 
 167   int native_nmethod_count;
 168   int native_total_size;
 169   int native_relocation_size;
 170   int native_insts_size;
 171   int native_oops_size;
 172   void note_native_nmethod(nmethod* nm) {
 173     native_nmethod_count += 1;
 174     native_total_size       += nm->size();
 175     native_relocation_size  += nm->relocation_size();
 176     native_insts_size       += nm->insts_size();
 177     native_oops_size        += nm->oops_size();
 178   }
 179   void print_native_nmethod_stats() {
 180     if (native_nmethod_count == 0)  return;
 181     tty->print_cr("Statistics for %d native nmethods:", native_nmethod_count);
 182     if (native_total_size != 0)       tty->print_cr(" N. total size  = %d", native_total_size);
 183     if (native_relocation_size != 0)  tty->print_cr(" N. relocation  = %d", native_relocation_size);
 184     if (native_insts_size != 0)       tty->print_cr(" N. main code   = %d", native_insts_size);
 185     if (native_oops_size != 0)        tty->print_cr(" N. oops        = %d", native_oops_size);
 186   }
 187 
 188   int pc_desc_resets;   // number of resets (= number of caches)
 189   int pc_desc_queries;  // queries to nmethod::find_pc_desc
 190   int pc_desc_approx;   // number of those which have approximate true
 191   int pc_desc_repeats;  // number of _pc_descs[0] hits
 192   int pc_desc_hits;     // number of LRU cache hits
 193   int pc_desc_tests;    // total number of PcDesc examinations
 194   int pc_desc_searches; // total number of quasi-binary search steps
 195   int pc_desc_adds;     // number of LUR cache insertions
 196 
 197   void print_pc_stats() {
 198     tty->print_cr("PcDesc Statistics:  %d queries, %.2f comparisons per query",
 199                   pc_desc_queries,
 200                   (double)(pc_desc_tests + pc_desc_searches)
 201                   / pc_desc_queries);
 202     tty->print_cr("  caches=%d queries=%d/%d, hits=%d+%d, tests=%d+%d, adds=%d",
 203                   pc_desc_resets,
 204                   pc_desc_queries, pc_desc_approx,
 205                   pc_desc_repeats, pc_desc_hits,
 206                   pc_desc_tests, pc_desc_searches, pc_desc_adds);
 207   }
 208 } nmethod_stats;
 209 #endif //PRODUCT
 210 
 211 
 212 //---------------------------------------------------------------------------------
 213 
 214 
 215 ExceptionCache::ExceptionCache(Handle exception, address pc, address handler) {
 216   assert(pc != NULL, "Must be non null");
 217   assert(exception.not_null(), "Must be non null");
 218   assert(handler != NULL, "Must be non null");
 219 
 220   _count = 0;
 221   _exception_type = exception->klass();
 222   _next = NULL;
 223 
 224   add_address_and_handler(pc,handler);
 225 }
 226 
 227 
 228 address ExceptionCache::match(Handle exception, address pc) {
 229   assert(pc != NULL,"Must be non null");
 230   assert(exception.not_null(),"Must be non null");
 231   if (exception->klass() == exception_type()) {
 232     return (test_address(pc));
 233   }
 234 
 235   return NULL;
 236 }
 237 
 238 
 239 bool ExceptionCache::match_exception_with_space(Handle exception) {
 240   assert(exception.not_null(),"Must be non null");
 241   if (exception->klass() == exception_type() && count() < cache_size) {
 242     return true;
 243   }
 244   return false;
 245 }
 246 
 247 
 248 address ExceptionCache::test_address(address addr) {
 249   for (int i=0; i<count(); i++) {
 250     if (pc_at(i) == addr) {
 251       return handler_at(i);
 252     }
 253   }
 254   return NULL;
 255 }
 256 
 257 
 258 bool ExceptionCache::add_address_and_handler(address addr, address handler) {
 259   if (test_address(addr) == handler) return true;
 260   if (count() < cache_size) {
 261     set_pc_at(count(),addr);
 262     set_handler_at(count(), handler);
 263     increment_count();
 264     return true;
 265   }
 266   return false;
 267 }
 268 
 269 
 270 // private method for handling exception cache
 271 // These methods are private, and used to manipulate the exception cache
 272 // directly.
 273 ExceptionCache* nmethod::exception_cache_entry_for_exception(Handle exception) {
 274   ExceptionCache* ec = exception_cache();
 275   while (ec != NULL) {
 276     if (ec->match_exception_with_space(exception)) {
 277       return ec;
 278     }
 279     ec = ec->next();
 280   }
 281   return NULL;
 282 }
 283 
 284 
 285 //-----------------------------------------------------------------------------
 286 
 287 
 288 // Helper used by both find_pc_desc methods.
 289 static inline bool match_desc(PcDesc* pc, int pc_offset, bool approximate) {
 290   NOT_PRODUCT(++nmethod_stats.pc_desc_tests);
 291   if (!approximate)
 292     return pc->pc_offset() == pc_offset;
 293   else
 294     return (pc-1)->pc_offset() < pc_offset && pc_offset <= pc->pc_offset();
 295 }
 296 
 297 void PcDescCache::reset_to(PcDesc* initial_pc_desc) {
 298   if (initial_pc_desc == NULL) {
 299     _pc_descs[0] = NULL; // native method; no PcDescs at all
 300     return;
 301   }
 302   NOT_PRODUCT(++nmethod_stats.pc_desc_resets);
 303   // reset the cache by filling it with benign (non-null) values
 304   assert(initial_pc_desc->pc_offset() < 0, "must be sentinel");
 305   for (int i = 0; i < cache_size; i++)
 306     _pc_descs[i] = initial_pc_desc;
 307 }
 308 
 309 PcDesc* PcDescCache::find_pc_desc(int pc_offset, bool approximate) {
 310   NOT_PRODUCT(++nmethod_stats.pc_desc_queries);
 311   NOT_PRODUCT(if (approximate) ++nmethod_stats.pc_desc_approx);
 312 
 313   // Note: one might think that caching the most recently
 314   // read value separately would be a win, but one would be
 315   // wrong.  When many threads are updating it, the cache
 316   // line it's in would bounce between caches, negating
 317   // any benefit.
 318 
 319   // In order to prevent race conditions do not load cache elements
 320   // repeatedly, but use a local copy:
 321   PcDesc* res;
 322 
 323   // Step one:  Check the most recently added value.
 324   res = _pc_descs[0];
 325   if (res == NULL) return NULL;  // native method; no PcDescs at all
 326   if (match_desc(res, pc_offset, approximate)) {
 327     NOT_PRODUCT(++nmethod_stats.pc_desc_repeats);
 328     return res;
 329   }
 330 
 331   // Step two:  Check the rest of the LRU cache.
 332   for (int i = 1; i < cache_size; ++i) {
 333     res = _pc_descs[i];
 334     if (res->pc_offset() < 0) break;  // optimization: skip empty cache
 335     if (match_desc(res, pc_offset, approximate)) {
 336       NOT_PRODUCT(++nmethod_stats.pc_desc_hits);
 337       return res;
 338     }
 339   }
 340 
 341   // Report failure.
 342   return NULL;
 343 }
 344 
 345 void PcDescCache::add_pc_desc(PcDesc* pc_desc) {
 346   NOT_PRODUCT(++nmethod_stats.pc_desc_adds);
 347   // Update the LRU cache by shifting pc_desc forward.
 348   for (int i = 0; i < cache_size; i++)  {
 349     PcDesc* next = _pc_descs[i];
 350     _pc_descs[i] = pc_desc;
 351     pc_desc = next;
 352   }
 353 }
 354 
 355 // adjust pcs_size so that it is a multiple of both oopSize and
 356 // sizeof(PcDesc) (assumes that if sizeof(PcDesc) is not a multiple
 357 // of oopSize, then 2*sizeof(PcDesc) is)
 358 static int adjust_pcs_size(int pcs_size) {
 359   int nsize = round_to(pcs_size,   oopSize);
 360   if ((nsize % sizeof(PcDesc)) != 0) {
 361     nsize = pcs_size + sizeof(PcDesc);
 362   }
 363   assert((nsize % oopSize) == 0, "correct alignment");
 364   return nsize;
 365 }
 366 
 367 //-----------------------------------------------------------------------------
 368 
 369 
 370 void nmethod::add_exception_cache_entry(ExceptionCache* new_entry) {
 371   assert(ExceptionCache_lock->owned_by_self(),"Must hold the ExceptionCache_lock");
 372   assert(new_entry != NULL,"Must be non null");
 373   assert(new_entry->next() == NULL, "Must be null");
 374 
 375   if (exception_cache() != NULL) {
 376     new_entry->set_next(exception_cache());
 377   }
 378   set_exception_cache(new_entry);
 379 }
 380 
 381 void nmethod::remove_from_exception_cache(ExceptionCache* ec) {
 382   ExceptionCache* prev = NULL;
 383   ExceptionCache* curr = exception_cache();
 384   assert(curr != NULL, "nothing to remove");
 385   // find the previous and next entry of ec
 386   while (curr != ec) {
 387     prev = curr;
 388     curr = curr->next();
 389     assert(curr != NULL, "ExceptionCache not found");
 390   }
 391   // now: curr == ec
 392   ExceptionCache* next = curr->next();
 393   if (prev == NULL) {
 394     set_exception_cache(next);
 395   } else {
 396     prev->set_next(next);
 397   }
 398   delete curr;
 399 }
 400 
 401 
 402 // public method for accessing the exception cache
 403 // These are the public access methods.
 404 address nmethod::handler_for_exception_and_pc(Handle exception, address pc) {
 405   // We never grab a lock to read the exception cache, so we may
 406   // have false negatives. This is okay, as it can only happen during
 407   // the first few exception lookups for a given nmethod.
 408   ExceptionCache* ec = exception_cache();
 409   while (ec != NULL) {
 410     address ret_val;
 411     if ((ret_val = ec->match(exception,pc)) != NULL) {
 412       return ret_val;
 413     }
 414     ec = ec->next();
 415   }
 416   return NULL;
 417 }
 418 
 419 
 420 void nmethod::add_handler_for_exception_and_pc(Handle exception, address pc, address handler) {
 421   // There are potential race conditions during exception cache updates, so we
 422   // must own the ExceptionCache_lock before doing ANY modifications. Because
 423   // we don't lock during reads, it is possible to have several threads attempt
 424   // to update the cache with the same data. We need to check for already inserted
 425   // copies of the current data before adding it.
 426 
 427   MutexLocker ml(ExceptionCache_lock);
 428   ExceptionCache* target_entry = exception_cache_entry_for_exception(exception);
 429 
 430   if (target_entry == NULL || !target_entry->add_address_and_handler(pc,handler)) {
 431     target_entry = new ExceptionCache(exception,pc,handler);
 432     add_exception_cache_entry(target_entry);
 433   }
 434 }
 435 
 436 
 437 //-------------end of code for ExceptionCache--------------
 438 
 439 
 440 int nmethod::total_size() const {
 441   return
 442     consts_size()        +
 443     insts_size()         +
 444     stub_size()          +
 445     scopes_data_size()   +
 446     scopes_pcs_size()    +
 447     handler_table_size() +
 448     nul_chk_table_size();
 449 }
 450 
 451 const char* nmethod::compile_kind() const {
 452   if (is_osr_method())     return "osr";
 453   if (method() != NULL && is_native_method())  return "c2n";
 454   return NULL;
 455 }
 456 
 457 // Fill in default values for various flag fields
 458 void nmethod::init_defaults() {
 459   _state                      = alive;
 460   _marked_for_reclamation     = 0;
 461   _has_flushed_dependencies   = 0;
 462   _speculatively_disconnected = 0;
 463   _has_unsafe_access          = 0;
 464   _has_method_handle_invokes  = 0;
 465   _marked_for_deoptimization  = 0;
 466   _lock_count                 = 0;
 467   _stack_traversal_mark       = 0;
 468   _unload_reported            = false;           // jvmti state
 469 
 470 #ifdef ASSERT
 471   _oops_are_stale             = false;
 472 #endif
 473 
 474   _oops_do_mark_link       = NULL;
 475   _jmethod_id              = NULL;
 476   _osr_link                = NULL;
 477   _scavenge_root_link      = NULL;
 478   _scavenge_root_state     = 0;
 479   _saved_nmethod_link      = NULL;
 480   _compiler                = NULL;
 481 
 482 #ifdef HAVE_DTRACE_H
 483   _trap_offset             = 0;
 484 #endif // def HAVE_DTRACE_H
 485 }
 486 
 487 
 488 nmethod* nmethod::new_native_nmethod(methodHandle method,
 489   int compile_id,
 490   CodeBuffer *code_buffer,
 491   int vep_offset,
 492   int frame_complete,
 493   int frame_size,
 494   ByteSize basic_lock_owner_sp_offset,
 495   ByteSize basic_lock_sp_offset,
 496   OopMapSet* oop_maps) {
 497   // create nmethod
 498   nmethod* nm = NULL;
 499   {
 500     MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
 501     int native_nmethod_size = allocation_size(code_buffer, sizeof(nmethod));
 502     CodeOffsets offsets;
 503     offsets.set_value(CodeOffsets::Verified_Entry, vep_offset);
 504     offsets.set_value(CodeOffsets::Frame_Complete, frame_complete);
 505     nm = new (native_nmethod_size)
 506       nmethod(method(), native_nmethod_size, compile_id, &offsets,
 507               code_buffer, frame_size,
 508               basic_lock_owner_sp_offset, basic_lock_sp_offset,
 509               oop_maps);
 510     NOT_PRODUCT(if (nm != NULL)  nmethod_stats.note_native_nmethod(nm));
 511     if (PrintAssembly && nm != NULL)
 512       Disassembler::decode(nm);
 513   }
 514   // verify nmethod
 515   debug_only(if (nm) nm->verify();) // might block
 516 
 517   if (nm != NULL) {
 518     nm->log_new_nmethod();
 519   }
 520 
 521   return nm;
 522 }
 523 
 524 #ifdef HAVE_DTRACE_H
 525 nmethod* nmethod::new_dtrace_nmethod(methodHandle method,
 526                                      CodeBuffer *code_buffer,
 527                                      int vep_offset,
 528                                      int trap_offset,
 529                                      int frame_complete,
 530                                      int frame_size) {
 531   // create nmethod
 532   nmethod* nm = NULL;
 533   {
 534     MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
 535     int nmethod_size = allocation_size(code_buffer, sizeof(nmethod));
 536     CodeOffsets offsets;
 537     offsets.set_value(CodeOffsets::Verified_Entry, vep_offset);
 538     offsets.set_value(CodeOffsets::Dtrace_trap, trap_offset);
 539     offsets.set_value(CodeOffsets::Frame_Complete, frame_complete);
 540 
 541     nm = new (nmethod_size) nmethod(method(), nmethod_size, &offsets, code_buffer, frame_size);
 542 
 543     NOT_PRODUCT(if (nm != NULL)  nmethod_stats.note_nmethod(nm));
 544     if (PrintAssembly && nm != NULL)
 545       Disassembler::decode(nm);
 546   }
 547   // verify nmethod
 548   debug_only(if (nm) nm->verify();) // might block
 549 
 550   if (nm != NULL) {
 551     nm->log_new_nmethod();
 552   }
 553 
 554   return nm;
 555 }
 556 
 557 #endif // def HAVE_DTRACE_H
 558 
 559 nmethod* nmethod::new_nmethod(methodHandle method,
 560   int compile_id,
 561   int entry_bci,
 562   CodeOffsets* offsets,
 563   int orig_pc_offset,
 564   DebugInformationRecorder* debug_info,
 565   Dependencies* dependencies,
 566   CodeBuffer* code_buffer, int frame_size,
 567   OopMapSet* oop_maps,
 568   ExceptionHandlerTable* handler_table,
 569   ImplicitExceptionTable* nul_chk_table,
 570   AbstractCompiler* compiler,
 571   int comp_level
 572 )
 573 {
 574   assert(debug_info->oop_recorder() == code_buffer->oop_recorder(), "shared OR");
 575   // create nmethod
 576   nmethod* nm = NULL;
 577   { MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
 578     int nmethod_size =
 579       allocation_size(code_buffer, sizeof(nmethod))
 580       + adjust_pcs_size(debug_info->pcs_size())
 581       + round_to(dependencies->size_in_bytes() , oopSize)
 582       + round_to(handler_table->size_in_bytes(), oopSize)
 583       + round_to(nul_chk_table->size_in_bytes(), oopSize)
 584       + round_to(debug_info->data_size()       , oopSize);
 585     nm = new (nmethod_size)
 586       nmethod(method(), nmethod_size, compile_id, entry_bci, offsets,
 587               orig_pc_offset, debug_info, dependencies, code_buffer, frame_size,
 588               oop_maps,
 589               handler_table,
 590               nul_chk_table,
 591               compiler,
 592               comp_level);
 593     if (nm != NULL) {
 594       // To make dependency checking during class loading fast, record
 595       // the nmethod dependencies in the classes it is dependent on.
 596       // This allows the dependency checking code to simply walk the
 597       // class hierarchy above the loaded class, checking only nmethods
 598       // which are dependent on those classes.  The slow way is to
 599       // check every nmethod for dependencies which makes it linear in
 600       // the number of methods compiled.  For applications with a lot
 601       // classes the slow way is too slow.
 602       for (Dependencies::DepStream deps(nm); deps.next(); ) {
 603         klassOop klass = deps.context_type();
 604         if (klass == NULL)  continue;  // ignore things like evol_method
 605 
 606         // record this nmethod as dependent on this klass
 607         instanceKlass::cast(klass)->add_dependent_nmethod(nm);
 608       }
 609     }
 610     NOT_PRODUCT(if (nm != NULL)  nmethod_stats.note_nmethod(nm));
 611     if (PrintAssembly && nm != NULL)
 612       Disassembler::decode(nm);
 613   }
 614 
 615   // verify nmethod
 616   debug_only(if (nm) nm->verify();) // might block
 617 
 618   if (nm != NULL) {
 619     nm->log_new_nmethod();
 620   }
 621 
 622   // done
 623   return nm;
 624 }
 625 
 626 
 627 // For native wrappers
 628 nmethod::nmethod(
 629   methodOop method,
 630   int nmethod_size,
 631   int compile_id,
 632   CodeOffsets* offsets,
 633   CodeBuffer* code_buffer,
 634   int frame_size,
 635   ByteSize basic_lock_owner_sp_offset,
 636   ByteSize basic_lock_sp_offset,
 637   OopMapSet* oop_maps )
 638   : CodeBlob("native nmethod", code_buffer, sizeof(nmethod),
 639              nmethod_size, offsets->value(CodeOffsets::Frame_Complete), frame_size, oop_maps),
 640   _native_receiver_sp_offset(basic_lock_owner_sp_offset),
 641   _native_basic_lock_sp_offset(basic_lock_sp_offset)
 642 {
 643   {
 644     debug_only(No_Safepoint_Verifier nsv;)
 645     assert_locked_or_safepoint(CodeCache_lock);
 646 
 647     init_defaults();
 648     _method                  = method;
 649     _entry_bci               = InvocationEntryBci;
 650     // We have no exception handler or deopt handler make the
 651     // values something that will never match a pc like the nmethod vtable entry
 652     _exception_offset        = 0;
 653     _deoptimize_offset       = 0;
 654     _deoptimize_mh_offset    = 0;
 655     _orig_pc_offset          = 0;
 656 
 657     _consts_offset           = data_offset();
 658     _stub_offset             = data_offset();
 659     _oops_offset             = data_offset();
 660     _scopes_data_offset      = _oops_offset          + round_to(code_buffer->total_oop_size(), oopSize);
 661     _scopes_pcs_offset       = _scopes_data_offset;
 662     _dependencies_offset     = _scopes_pcs_offset;
 663     _handler_table_offset    = _dependencies_offset;
 664     _nul_chk_table_offset    = _handler_table_offset;
 665     _nmethod_end_offset      = _nul_chk_table_offset;
 666     _compile_id              = compile_id;
 667     _comp_level              = CompLevel_none;
 668     _entry_point             = code_begin()          + offsets->value(CodeOffsets::Entry);
 669     _verified_entry_point    = code_begin()          + offsets->value(CodeOffsets::Verified_Entry);
 670     _osr_entry_point         = NULL;
 671     _exception_cache         = NULL;
 672     _pc_desc_cache.reset_to(NULL);
 673 
 674     code_buffer->copy_oops_to(this);
 675     if (ScavengeRootsInCode && detect_scavenge_root_oops()) {
 676       CodeCache::add_scavenge_root_nmethod(this);
 677     }
 678     debug_only(verify_scavenge_root_oops());
 679     CodeCache::commit(this);
 680   }
 681 
 682   if (PrintNativeNMethods || PrintDebugInfo || PrintRelocations || PrintDependencies) {
 683     ttyLocker ttyl;  // keep the following output all in one block
 684     // This output goes directly to the tty, not the compiler log.
 685     // To enable tools to match it up with the compilation activity,
 686     // be sure to tag this tty output with the compile ID.
 687     if (xtty != NULL) {
 688       xtty->begin_head("print_native_nmethod");
 689       xtty->method(_method);
 690       xtty->stamp();
 691       xtty->end_head(" address='" INTPTR_FORMAT "'", (intptr_t) this);
 692     }
 693     // print the header part first
 694     print();
 695     // then print the requested information
 696     if (PrintNativeNMethods) {
 697       print_code();
 698       oop_maps->print();
 699     }
 700     if (PrintRelocations) {
 701       print_relocations();
 702     }
 703     if (xtty != NULL) {
 704       xtty->tail("print_native_nmethod");
 705     }
 706   }
 707   Events::log("Create nmethod " INTPTR_FORMAT, this);
 708 }
 709 
 710 // For dtrace wrappers
 711 #ifdef HAVE_DTRACE_H
 712 nmethod::nmethod(
 713   methodOop method,
 714   int nmethod_size,
 715   CodeOffsets* offsets,
 716   CodeBuffer* code_buffer,
 717   int frame_size)
 718   : CodeBlob("dtrace nmethod", code_buffer, sizeof(nmethod),
 719              nmethod_size, offsets->value(CodeOffsets::Frame_Complete), frame_size, NULL),
 720   _native_receiver_sp_offset(in_ByteSize(-1)),
 721   _native_basic_lock_sp_offset(in_ByteSize(-1))
 722 {
 723   {
 724     debug_only(No_Safepoint_Verifier nsv;)
 725     assert_locked_or_safepoint(CodeCache_lock);
 726 
 727     init_defaults();
 728     _method                  = method;
 729     _entry_bci               = InvocationEntryBci;
 730     // We have no exception handler or deopt handler make the
 731     // values something that will never match a pc like the nmethod vtable entry
 732     _exception_offset        = 0;
 733     _deoptimize_offset       = 0;
 734     _deoptimize_mh_offset    = 0;
 735     _unwind_handler_offset   = -1;
 736     _trap_offset             = offsets->value(CodeOffsets::Dtrace_trap);
 737     _orig_pc_offset          = 0;
 738     _consts_offset           = data_offset();
 739     _stub_offset             = data_offset();
 740     _oops_offset             = data_offset();
 741     _scopes_data_offset      = _oops_offset          + round_to(code_buffer->total_oop_size(), oopSize);
 742     _scopes_pcs_offset       = _scopes_data_offset;
 743     _dependencies_offset     = _scopes_pcs_offset;
 744     _handler_table_offset    = _dependencies_offset;
 745     _nul_chk_table_offset    = _handler_table_offset;
 746     _nmethod_end_offset      = _nul_chk_table_offset;
 747     _compile_id              = 0;  // default
 748     _comp_level              = CompLevel_none;
 749     _entry_point             = code_begin()          + offsets->value(CodeOffsets::Entry);
 750     _verified_entry_point    = code_begin()          + offsets->value(CodeOffsets::Verified_Entry);
 751     _osr_entry_point         = NULL;
 752     _exception_cache         = NULL;
 753     _pc_desc_cache.reset_to(NULL);
 754 
 755     code_buffer->copy_oops_to(this);
 756     debug_only(verify_scavenge_root_oops());
 757     CodeCache::commit(this);
 758   }
 759 
 760   if (PrintNMethods || PrintDebugInfo || PrintRelocations || PrintDependencies) {
 761     ttyLocker ttyl;  // keep the following output all in one block
 762     // This output goes directly to the tty, not the compiler log.
 763     // To enable tools to match it up with the compilation activity,
 764     // be sure to tag this tty output with the compile ID.
 765     if (xtty != NULL) {
 766       xtty->begin_head("print_dtrace_nmethod");
 767       xtty->method(_method);
 768       xtty->stamp();
 769       xtty->end_head(" address='" INTPTR_FORMAT "'", (intptr_t) this);
 770     }
 771     // print the header part first
 772     print();
 773     // then print the requested information
 774     if (PrintNMethods) {
 775       print_code();
 776     }
 777     if (PrintRelocations) {
 778       print_relocations();
 779     }
 780     if (xtty != NULL) {
 781       xtty->tail("print_dtrace_nmethod");
 782     }
 783   }
 784   Events::log("Create nmethod " INTPTR_FORMAT, this);
 785 }
 786 #endif // def HAVE_DTRACE_H
 787 
 788 void* nmethod::operator new(size_t size, int nmethod_size) {
 789   // Always leave some room in the CodeCache for I2C/C2I adapters
 790   if (CodeCache::largest_free_block() < CodeCacheMinimumFreeSpace) return NULL;
 791   return CodeCache::allocate(nmethod_size);
 792 }
 793 
 794 
 795 nmethod::nmethod(
 796   methodOop method,
 797   int nmethod_size,
 798   int compile_id,
 799   int entry_bci,
 800   CodeOffsets* offsets,
 801   int orig_pc_offset,
 802   DebugInformationRecorder* debug_info,
 803   Dependencies* dependencies,
 804   CodeBuffer *code_buffer,
 805   int frame_size,
 806   OopMapSet* oop_maps,
 807   ExceptionHandlerTable* handler_table,
 808   ImplicitExceptionTable* nul_chk_table,
 809   AbstractCompiler* compiler,
 810   int comp_level
 811   )
 812   : CodeBlob("nmethod", code_buffer, sizeof(nmethod),
 813              nmethod_size, offsets->value(CodeOffsets::Frame_Complete), frame_size, oop_maps),
 814   _native_receiver_sp_offset(in_ByteSize(-1)),
 815   _native_basic_lock_sp_offset(in_ByteSize(-1))
 816 {
 817   assert(debug_info->oop_recorder() == code_buffer->oop_recorder(), "shared OR");
 818   {
 819     debug_only(No_Safepoint_Verifier nsv;)
 820     assert_locked_or_safepoint(CodeCache_lock);
 821 
 822     init_defaults();
 823     _method                  = method;
 824     _entry_bci               = entry_bci;
 825     _compile_id              = compile_id;
 826     _comp_level              = comp_level;
 827     _compiler                = compiler;
 828     _orig_pc_offset          = orig_pc_offset;
 829 
 830     // Section offsets
 831     _consts_offset           = content_offset()      + code_buffer->total_offset_of(code_buffer->consts());
 832     _stub_offset             = content_offset()      + code_buffer->total_offset_of(code_buffer->stubs());
 833 
 834     // Exception handler and deopt handler are in the stub section
 835     assert(offsets->value(CodeOffsets::Exceptions) != -1, "must be set");
 836     assert(offsets->value(CodeOffsets::Deopt     ) != -1, "must be set");
 837     _exception_offset        = _stub_offset          + offsets->value(CodeOffsets::Exceptions);
 838     _deoptimize_offset       = _stub_offset          + offsets->value(CodeOffsets::Deopt);
 839     if (offsets->value(CodeOffsets::DeoptMH) != -1) {
 840       _deoptimize_mh_offset  = _stub_offset          + offsets->value(CodeOffsets::DeoptMH);
 841     } else {
 842       _deoptimize_mh_offset  = -1;
 843     }
 844     if (offsets->value(CodeOffsets::UnwindHandler) != -1) {
 845       _unwind_handler_offset = code_offset()         + offsets->value(CodeOffsets::UnwindHandler);
 846     } else {
 847       _unwind_handler_offset = -1;
 848     }
 849 
 850     _oops_offset             = data_offset();
 851     _scopes_data_offset      = _oops_offset          + round_to(code_buffer->total_oop_size (), oopSize);
 852     _scopes_pcs_offset       = _scopes_data_offset   + round_to(debug_info->data_size       (), oopSize);
 853     _dependencies_offset     = _scopes_pcs_offset    + adjust_pcs_size(debug_info->pcs_size());
 854     _handler_table_offset    = _dependencies_offset  + round_to(dependencies->size_in_bytes (), oopSize);
 855     _nul_chk_table_offset    = _handler_table_offset + round_to(handler_table->size_in_bytes(), oopSize);
 856     _nmethod_end_offset      = _nul_chk_table_offset + round_to(nul_chk_table->size_in_bytes(), oopSize);
 857 
 858     _entry_point             = code_begin()          + offsets->value(CodeOffsets::Entry);
 859     _verified_entry_point    = code_begin()          + offsets->value(CodeOffsets::Verified_Entry);
 860     _osr_entry_point         = code_begin()          + offsets->value(CodeOffsets::OSR_Entry);
 861     _exception_cache         = NULL;
 862     _pc_desc_cache.reset_to(scopes_pcs_begin());
 863 
 864     // Copy contents of ScopeDescRecorder to nmethod
 865     code_buffer->copy_oops_to(this);
 866     debug_info->copy_to(this);
 867     dependencies->copy_to(this);
 868     if (ScavengeRootsInCode && detect_scavenge_root_oops()) {
 869       CodeCache::add_scavenge_root_nmethod(this);
 870     }
 871     debug_only(verify_scavenge_root_oops());
 872 
 873     CodeCache::commit(this);
 874 
 875     // Copy contents of ExceptionHandlerTable to nmethod
 876     handler_table->copy_to(this);
 877     nul_chk_table->copy_to(this);
 878 
 879     // we use the information of entry points to find out if a method is
 880     // static or non static
 881     assert(compiler->is_c2() ||
 882            _method->is_static() == (entry_point() == _verified_entry_point),
 883            " entry points must be same for static methods and vice versa");
 884   }
 885 
 886   bool printnmethods = PrintNMethods
 887     || CompilerOracle::should_print(_method)
 888     || CompilerOracle::has_option_string(_method, "PrintNMethods");
 889   if (printnmethods || PrintDebugInfo || PrintRelocations || PrintDependencies || PrintExceptionHandlers) {
 890     print_nmethod(printnmethods);
 891   }
 892 
 893   // Note: Do not verify in here as the CodeCache_lock is
 894   //       taken which would conflict with the CompiledIC_lock
 895   //       which taken during the verification of call sites.
 896   //       (was bug - gri 10/25/99)
 897 
 898   Events::log("Create nmethod " INTPTR_FORMAT, this);
 899 }
 900 
 901 
 902 // Print a short set of xml attributes to identify this nmethod.  The
 903 // output should be embedded in some other element.
 904 void nmethod::log_identity(xmlStream* log) const {
 905   log->print(" compile_id='%d'", compile_id());
 906   const char* nm_kind = compile_kind();
 907   if (nm_kind != NULL)  log->print(" compile_kind='%s'", nm_kind);
 908   if (compiler() != NULL) {
 909     log->print(" compiler='%s'", compiler()->name());
 910   }
 911   if (TieredCompilation) {
 912     log->print(" level='%d'", comp_level());
 913   }
 914 }
 915 
 916 
 917 #define LOG_OFFSET(log, name)                    \
 918   if ((intptr_t)name##_end() - (intptr_t)name##_begin()) \
 919     log->print(" " XSTR(name) "_offset='%d'"    , \
 920                (intptr_t)name##_begin() - (intptr_t)this)
 921 
 922 
 923 void nmethod::log_new_nmethod() const {
 924   if (LogCompilation && xtty != NULL) {
 925     ttyLocker ttyl;
 926     HandleMark hm;
 927     xtty->begin_elem("nmethod");
 928     log_identity(xtty);
 929     xtty->print(" entry='" INTPTR_FORMAT "' size='%d'", code_begin(), size());
 930     xtty->print(" address='" INTPTR_FORMAT "'", (intptr_t) this);
 931 
 932     LOG_OFFSET(xtty, relocation);
 933     LOG_OFFSET(xtty, consts);
 934     LOG_OFFSET(xtty, insts);
 935     LOG_OFFSET(xtty, stub);
 936     LOG_OFFSET(xtty, scopes_data);
 937     LOG_OFFSET(xtty, scopes_pcs);
 938     LOG_OFFSET(xtty, dependencies);
 939     LOG_OFFSET(xtty, handler_table);
 940     LOG_OFFSET(xtty, nul_chk_table);
 941     LOG_OFFSET(xtty, oops);
 942 
 943     xtty->method(method());
 944     xtty->stamp();
 945     xtty->end_elem();
 946   }
 947 }
 948 
 949 #undef LOG_OFFSET
 950 
 951 
 952 // Print out more verbose output usually for a newly created nmethod.
 953 void nmethod::print_on(outputStream* st, const char* msg) const {
 954   if (st != NULL) {
 955     ttyLocker ttyl;
 956     CompileTask::print_compilation(st, this, msg);
 957     if (WizardMode) st->print(" (" INTPTR_FORMAT ")", this);
 958   }
 959 }
 960 
 961 
 962 void nmethod::print_nmethod(bool printmethod) {
 963   ttyLocker ttyl;  // keep the following output all in one block
 964   if (xtty != NULL) {
 965     xtty->begin_head("print_nmethod");
 966     xtty->stamp();
 967     xtty->end_head();
 968   }
 969   // print the header part first
 970   print();
 971   // then print the requested information
 972   if (printmethod) {
 973     print_code();
 974     print_pcs();
 975     oop_maps()->print();
 976   }
 977   if (PrintDebugInfo) {
 978     print_scopes();
 979   }
 980   if (PrintRelocations) {
 981     print_relocations();
 982   }
 983   if (PrintDependencies) {
 984     print_dependencies();
 985   }
 986   if (PrintExceptionHandlers) {
 987     print_handler_table();
 988     print_nul_chk_table();
 989   }
 990   if (xtty != NULL) {
 991     xtty->tail("print_nmethod");
 992   }
 993 }
 994 
 995 
 996 // Promote one word from an assembly-time handle to a live embedded oop.
 997 inline void nmethod::initialize_immediate_oop(oop* dest, jobject handle) {
 998   if (handle == NULL ||
 999       // As a special case, IC oops are initialized to 1 or -1.
1000       handle == (jobject) Universe::non_oop_word()) {
1001     (*dest) = (oop) handle;
1002   } else {
1003     (*dest) = JNIHandles::resolve_non_null(handle);
1004   }
1005 }
1006 
1007 
1008 void nmethod::copy_oops(GrowableArray<jobject>* array) {
1009   //assert(oops_size() == 0, "do this handshake just once, please");
1010   int length = array->length();
1011   assert((address)(oops_begin() + length) <= data_end(), "oops big enough");
1012   oop* dest = oops_begin();
1013   for (int index = 0 ; index < length; index++) {
1014     initialize_immediate_oop(&dest[index], array->at(index));
1015   }
1016 
1017   // Now we can fix up all the oops in the code.  We need to do this
1018   // in the code because the assembler uses jobjects as placeholders.
1019   // The code and relocations have already been initialized by the
1020   // CodeBlob constructor, so it is valid even at this early point to
1021   // iterate over relocations and patch the code.
1022   fix_oop_relocations(NULL, NULL, /*initialize_immediates=*/ true);
1023 }
1024 
1025 
1026 bool nmethod::is_at_poll_return(address pc) {
1027   RelocIterator iter(this, pc, pc+1);
1028   while (iter.next()) {
1029     if (iter.type() == relocInfo::poll_return_type)
1030       return true;
1031   }
1032   return false;
1033 }
1034 
1035 
1036 bool nmethod::is_at_poll_or_poll_return(address pc) {
1037   RelocIterator iter(this, pc, pc+1);
1038   while (iter.next()) {
1039     relocInfo::relocType t = iter.type();
1040     if (t == relocInfo::poll_return_type || t == relocInfo::poll_type)
1041       return true;
1042   }
1043   return false;
1044 }
1045 
1046 
1047 void nmethod::fix_oop_relocations(address begin, address end, bool initialize_immediates) {
1048   // re-patch all oop-bearing instructions, just in case some oops moved
1049   RelocIterator iter(this, begin, end);
1050   while (iter.next()) {
1051     if (iter.type() == relocInfo::oop_type) {
1052       oop_Relocation* reloc = iter.oop_reloc();
1053       if (initialize_immediates && reloc->oop_is_immediate()) {
1054         oop* dest = reloc->oop_addr();
1055         initialize_immediate_oop(dest, (jobject) *dest);
1056       }
1057       // Refresh the oop-related bits of this instruction.
1058       reloc->fix_oop_relocation();
1059     }
1060 
1061     // There must not be any interfering patches or breakpoints.
1062     assert(!(iter.type() == relocInfo::breakpoint_type
1063              && iter.breakpoint_reloc()->active()),
1064            "no active breakpoint");
1065   }
1066 }
1067 
1068 
1069 void nmethod::verify_oop_relocations() {
1070   // Ensure sure that the code matches the current oop values
1071   RelocIterator iter(this, NULL, NULL);
1072   while (iter.next()) {
1073     if (iter.type() == relocInfo::oop_type) {
1074       oop_Relocation* reloc = iter.oop_reloc();
1075       if (!reloc->oop_is_immediate()) {
1076         reloc->verify_oop_relocation();
1077       }
1078     }
1079   }
1080 }
1081 
1082 
1083 ScopeDesc* nmethod::scope_desc_at(address pc) {
1084   PcDesc* pd = pc_desc_at(pc);
1085   guarantee(pd != NULL, "scope must be present");
1086   return new ScopeDesc(this, pd->scope_decode_offset(),
1087                        pd->obj_decode_offset(), pd->should_reexecute(),
1088                        pd->return_oop());
1089 }
1090 
1091 
1092 void nmethod::clear_inline_caches() {
1093   assert(SafepointSynchronize::is_at_safepoint(), "cleaning of IC's only allowed at safepoint");
1094   if (is_zombie()) {
1095     return;
1096   }
1097 
1098   RelocIterator iter(this);
1099   while (iter.next()) {
1100     iter.reloc()->clear_inline_cache();
1101   }
1102 }
1103 
1104 
1105 void nmethod::cleanup_inline_caches() {
1106 
1107   assert_locked_or_safepoint(CompiledIC_lock);
1108 
1109   // If the method is not entrant or zombie then a JMP is plastered over the
1110   // first few bytes.  If an oop in the old code was there, that oop
1111   // should not get GC'd.  Skip the first few bytes of oops on
1112   // not-entrant methods.
1113   address low_boundary = verified_entry_point();
1114   if (!is_in_use()) {
1115     low_boundary += NativeJump::instruction_size;
1116     // %%% Note:  On SPARC we patch only a 4-byte trap, not a full NativeJump.
1117     // This means that the low_boundary is going to be a little too high.
1118     // This shouldn't matter, since oops of non-entrant methods are never used.
1119     // In fact, why are we bothering to look at oops in a non-entrant method??
1120   }
1121 
1122   // Find all calls in an nmethod, and clear the ones that points to zombie methods
1123   ResourceMark rm;
1124   RelocIterator iter(this, low_boundary);
1125   while(iter.next()) {
1126     switch(iter.type()) {
1127       case relocInfo::virtual_call_type:
1128       case relocInfo::opt_virtual_call_type: {
1129         CompiledIC *ic = CompiledIC_at(iter.reloc());
1130         // Ok, to lookup references to zombies here
1131         CodeBlob *cb = CodeCache::find_blob_unsafe(ic->ic_destination());
1132         if( cb != NULL && cb->is_nmethod() ) {
1133           nmethod* nm = (nmethod*)cb;
1134           // Clean inline caches pointing to both zombie and not_entrant methods
1135           if (!nm->is_in_use() || (nm->method()->code() != nm)) ic->set_to_clean();
1136         }
1137         break;
1138       }
1139       case relocInfo::static_call_type: {
1140         CompiledStaticCall *csc = compiledStaticCall_at(iter.reloc());
1141         CodeBlob *cb = CodeCache::find_blob_unsafe(csc->destination());
1142         if( cb != NULL && cb->is_nmethod() ) {
1143           nmethod* nm = (nmethod*)cb;
1144           // Clean inline caches pointing to both zombie and not_entrant methods
1145           if (!nm->is_in_use() || (nm->method()->code() != nm)) csc->set_to_clean();
1146         }
1147         break;
1148       }
1149     }
1150   }
1151 }
1152 
1153 // This is a private interface with the sweeper.
1154 void nmethod::mark_as_seen_on_stack() {
1155   assert(is_not_entrant(), "must be a non-entrant method");
1156   // Set the traversal mark to ensure that the sweeper does 2
1157   // cleaning passes before moving to zombie.
1158   set_stack_traversal_mark(NMethodSweeper::traversal_count());
1159 }
1160 
1161 // Tell if a non-entrant method can be converted to a zombie (i.e.,
1162 // there are no activations on the stack, not in use by the VM,
1163 // and not in use by the ServiceThread)
1164 bool nmethod::can_not_entrant_be_converted() {
1165   assert(is_not_entrant(), "must be a non-entrant method");
1166 
1167   // Since the nmethod sweeper only does partial sweep the sweeper's traversal
1168   // count can be greater than the stack traversal count before it hits the
1169   // nmethod for the second time.
1170   return stack_traversal_mark()+1 < NMethodSweeper::traversal_count() &&
1171          !is_locked_by_vm();
1172 }
1173 
1174 void nmethod::inc_decompile_count() {
1175   if (!is_compiled_by_c2()) return;
1176   // Could be gated by ProfileTraps, but do not bother...
1177   methodOop m = method();
1178   if (m == NULL)  return;
1179   methodDataOop mdo = m->method_data();
1180   if (mdo == NULL)  return;
1181   // There is a benign race here.  See comments in methodDataOop.hpp.
1182   mdo->inc_decompile_count();
1183 }
1184 
1185 void nmethod::make_unloaded(BoolObjectClosure* is_alive, oop cause) {
1186 
1187   post_compiled_method_unload();
1188 
1189   // Since this nmethod is being unloaded, make sure that dependencies
1190   // recorded in instanceKlasses get flushed and pass non-NULL closure to
1191   // indicate that this work is being done during a GC.
1192   assert(Universe::heap()->is_gc_active(), "should only be called during gc");
1193   assert(is_alive != NULL, "Should be non-NULL");
1194   // A non-NULL is_alive closure indicates that this is being called during GC.
1195   flush_dependencies(is_alive);
1196 
1197   // Break cycle between nmethod & method
1198   if (TraceClassUnloading && WizardMode) {
1199     tty->print_cr("[Class unloading: Making nmethod " INTPTR_FORMAT
1200                   " unloadable], methodOop(" INTPTR_FORMAT
1201                   "), cause(" INTPTR_FORMAT ")",
1202                   this, (address)_method, (address)cause);
1203     if (!Universe::heap()->is_gc_active())
1204       cause->klass()->print();
1205   }
1206   // Unlink the osr method, so we do not look this up again
1207   if (is_osr_method()) {
1208     invalidate_osr_method();
1209   }
1210   // If _method is already NULL the methodOop is about to be unloaded,
1211   // so we don't have to break the cycle. Note that it is possible to
1212   // have the methodOop live here, in case we unload the nmethod because
1213   // it is pointing to some oop (other than the methodOop) being unloaded.
1214   if (_method != NULL) {
1215     // OSR methods point to the methodOop, but the methodOop does not
1216     // point back!
1217     if (_method->code() == this) {
1218       _method->clear_code(); // Break a cycle
1219     }
1220     _method = NULL;            // Clear the method of this dead nmethod
1221   }
1222   // Make the class unloaded - i.e., change state and notify sweeper
1223   assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
1224   if (is_in_use()) {
1225     // Transitioning directly from live to unloaded -- so
1226     // we need to force a cache clean-up; remember this
1227     // for later on.
1228     CodeCache::set_needs_cache_clean(true);
1229   }
1230   _state = unloaded;
1231 
1232   // Log the unloading.
1233   log_state_change();
1234 
1235   // The methodOop is gone at this point
1236   assert(_method == NULL, "Tautology");
1237 
1238   set_osr_link(NULL);
1239   //set_scavenge_root_link(NULL); // done by prune_scavenge_root_nmethods
1240   NMethodSweeper::notify(this);
1241 }
1242 
1243 void nmethod::invalidate_osr_method() {
1244   assert(_entry_bci != InvocationEntryBci, "wrong kind of nmethod");
1245   // Remove from list of active nmethods
1246   if (method() != NULL)
1247     instanceKlass::cast(method()->method_holder())->remove_osr_nmethod(this);
1248   // Set entry as invalid
1249   _entry_bci = InvalidOSREntryBci;
1250 }
1251 
1252 void nmethod::log_state_change() const {
1253   if (LogCompilation) {
1254     if (xtty != NULL) {
1255       ttyLocker ttyl;  // keep the following output all in one block
1256       if (_state == unloaded) {
1257         xtty->begin_elem("make_unloaded thread='" UINTX_FORMAT "'",
1258                          os::current_thread_id());
1259       } else {
1260         xtty->begin_elem("make_not_entrant thread='" UINTX_FORMAT "'%s",
1261                          os::current_thread_id(),
1262                          (_state == zombie ? " zombie='1'" : ""));
1263       }
1264       log_identity(xtty);
1265       xtty->stamp();
1266       xtty->end_elem();
1267     }
1268   }
1269   if (PrintCompilation && _state != unloaded) {
1270     print_on(tty, _state == zombie ? "made zombie" : "made not entrant");
1271   }
1272 }
1273 
1274 // Common functionality for both make_not_entrant and make_zombie
1275 bool nmethod::make_not_entrant_or_zombie(unsigned int state) {
1276   assert(state == zombie || state == not_entrant, "must be zombie or not_entrant");
1277   assert(!is_zombie(), "should not already be a zombie");
1278 
1279   // Make sure neither the nmethod nor the method is flushed in case of a safepoint in code below.
1280   nmethodLocker nml(this);
1281   methodHandle the_method(method());
1282   No_Safepoint_Verifier nsv;
1283 
1284   {
1285     // invalidate osr nmethod before acquiring the patching lock since
1286     // they both acquire leaf locks and we don't want a deadlock.
1287     // This logic is equivalent to the logic below for patching the
1288     // verified entry point of regular methods.
1289     if (is_osr_method()) {
1290       // this effectively makes the osr nmethod not entrant
1291       invalidate_osr_method();
1292     }
1293 
1294     // Enter critical section.  Does not block for safepoint.
1295     MutexLockerEx pl(Patching_lock, Mutex::_no_safepoint_check_flag);
1296 
1297     if (_state == state) {
1298       // another thread already performed this transition so nothing
1299       // to do, but return false to indicate this.
1300       return false;
1301     }
1302 
1303     // The caller can be calling the method statically or through an inline
1304     // cache call.
1305     if (!is_osr_method() && !is_not_entrant()) {
1306       NativeJump::patch_verified_entry(entry_point(), verified_entry_point(),
1307                   SharedRuntime::get_handle_wrong_method_stub());
1308     }
1309 
1310     if (is_in_use()) {
1311       // It's a true state change, so mark the method as decompiled.
1312       // Do it only for transition from alive.
1313       inc_decompile_count();
1314     }
1315 
1316     // Change state
1317     _state = state;
1318 
1319     // Log the transition once
1320     log_state_change();
1321 
1322     // Remove nmethod from method.
1323     // We need to check if both the _code and _from_compiled_code_entry_point
1324     // refer to this nmethod because there is a race in setting these two fields
1325     // in methodOop as seen in bugid 4947125.
1326     // If the vep() points to the zombie nmethod, the memory for the nmethod
1327     // could be flushed and the compiler and vtable stubs could still call
1328     // through it.
1329     if (method() != NULL && (method()->code() == this ||
1330                              method()->from_compiled_entry() == verified_entry_point())) {
1331       HandleMark hm;
1332       method()->clear_code();
1333     }
1334 
1335     if (state == not_entrant) {
1336       mark_as_seen_on_stack();
1337     }
1338 
1339   } // leave critical region under Patching_lock
1340 
1341   // When the nmethod becomes zombie it is no longer alive so the
1342   // dependencies must be flushed.  nmethods in the not_entrant
1343   // state will be flushed later when the transition to zombie
1344   // happens or they get unloaded.
1345   if (state == zombie) {
1346     {
1347       // Flushing dependecies must be done before any possible
1348       // safepoint can sneak in, otherwise the oops used by the
1349       // dependency logic could have become stale.
1350       MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
1351       flush_dependencies(NULL);
1352     }
1353 
1354     // zombie only - if a JVMTI agent has enabled the CompiledMethodUnload
1355     // event and it hasn't already been reported for this nmethod then
1356     // report it now. The event may have been reported earilier if the GC
1357     // marked it for unloading). JvmtiDeferredEventQueue support means
1358     // we no longer go to a safepoint here.
1359     post_compiled_method_unload();
1360 
1361 #ifdef ASSERT
1362     // It's no longer safe to access the oops section since zombie
1363     // nmethods aren't scanned for GC.
1364     _oops_are_stale = true;
1365 #endif
1366   } else {
1367     assert(state == not_entrant, "other cases may need to be handled differently");
1368   }
1369 
1370   if (TraceCreateZombies) {
1371     tty->print_cr("nmethod <" INTPTR_FORMAT "> code made %s", this, (state == not_entrant) ? "not entrant" : "zombie");
1372   }
1373 
1374   // Make sweeper aware that there is a zombie method that needs to be removed
1375   NMethodSweeper::notify(this);
1376 
1377   return true;
1378 }
1379 
1380 void nmethod::flush() {
1381   // Note that there are no valid oops in the nmethod anymore.
1382   assert(is_zombie() || (is_osr_method() && is_unloaded()), "must be a zombie method");
1383   assert(is_marked_for_reclamation() || (is_osr_method() && is_unloaded()), "must be marked for reclamation");
1384 
1385   assert (!is_locked_by_vm(), "locked methods shouldn't be flushed");
1386   assert_locked_or_safepoint(CodeCache_lock);
1387 
1388   // completely deallocate this method
1389   EventMark m("flushing nmethod " INTPTR_FORMAT " %s", this, "");
1390   if (PrintMethodFlushing) {
1391     tty->print_cr("*flushing nmethod %3d/" INTPTR_FORMAT ". Live blobs:" UINT32_FORMAT "/Free CodeCache:" SIZE_FORMAT "Kb",
1392         _compile_id, this, CodeCache::nof_blobs(), CodeCache::unallocated_capacity()/1024);
1393   }
1394 
1395   // We need to deallocate any ExceptionCache data.
1396   // Note that we do not need to grab the nmethod lock for this, it
1397   // better be thread safe if we're disposing of it!
1398   ExceptionCache* ec = exception_cache();
1399   set_exception_cache(NULL);
1400   while(ec != NULL) {
1401     ExceptionCache* next = ec->next();
1402     delete ec;
1403     ec = next;
1404   }
1405 
1406   if (on_scavenge_root_list()) {
1407     CodeCache::drop_scavenge_root_nmethod(this);
1408   }
1409 
1410   if (is_speculatively_disconnected()) {
1411     CodeCache::remove_saved_code(this);
1412   }
1413 
1414 #ifdef SHARK
1415   ((SharkCompiler *) compiler())->free_compiled_method(insts_begin());
1416 #endif // SHARK
1417 
1418   ((CodeBlob*)(this))->flush();
1419 
1420   CodeCache::free(this);
1421 }
1422 
1423 
1424 //
1425 // Notify all classes this nmethod is dependent on that it is no
1426 // longer dependent. This should only be called in two situations.
1427 // First, when a nmethod transitions to a zombie all dependents need
1428 // to be clear.  Since zombification happens at a safepoint there's no
1429 // synchronization issues.  The second place is a little more tricky.
1430 // During phase 1 of mark sweep class unloading may happen and as a
1431 // result some nmethods may get unloaded.  In this case the flushing
1432 // of dependencies must happen during phase 1 since after GC any
1433 // dependencies in the unloaded nmethod won't be updated, so
1434 // traversing the dependency information in unsafe.  In that case this
1435 // function is called with a non-NULL argument and this function only
1436 // notifies instanceKlasses that are reachable
1437 
1438 void nmethod::flush_dependencies(BoolObjectClosure* is_alive) {
1439   assert_locked_or_safepoint(CodeCache_lock);
1440   assert(Universe::heap()->is_gc_active() == (is_alive != NULL),
1441   "is_alive is non-NULL if and only if we are called during GC");
1442   if (!has_flushed_dependencies()) {
1443     set_has_flushed_dependencies();
1444     for (Dependencies::DepStream deps(this); deps.next(); ) {
1445       klassOop klass = deps.context_type();
1446       if (klass == NULL)  continue;  // ignore things like evol_method
1447 
1448       // During GC the is_alive closure is non-NULL, and is used to
1449       // determine liveness of dependees that need to be updated.
1450       if (is_alive == NULL || is_alive->do_object_b(klass)) {
1451         instanceKlass::cast(klass)->remove_dependent_nmethod(this);
1452       }
1453     }
1454   }
1455 }
1456 
1457 
1458 // If this oop is not live, the nmethod can be unloaded.
1459 bool nmethod::can_unload(BoolObjectClosure* is_alive,
1460                          OopClosure* keep_alive,
1461                          oop* root, bool unloading_occurred) {
1462   assert(root != NULL, "just checking");
1463   oop obj = *root;
1464   if (obj == NULL || is_alive->do_object_b(obj)) {
1465       return false;
1466   }
1467   if (obj->is_compiledICHolder()) {
1468     compiledICHolderOop cichk_oop = compiledICHolderOop(obj);
1469     if (is_alive->do_object_b(
1470           cichk_oop->holder_method()->method_holder()) &&
1471         is_alive->do_object_b(cichk_oop->holder_klass())) {
1472       // The oop should be kept alive
1473       keep_alive->do_oop(root);
1474       return false;
1475     }
1476   }
1477   // If ScavengeRootsInCode is true, an nmethod might be unloaded
1478   // simply because one of its constant oops has gone dead.
1479   // No actual classes need to be unloaded in order for this to occur.
1480   assert(unloading_occurred || ScavengeRootsInCode, "Inconsistency in unloading");
1481   make_unloaded(is_alive, obj);
1482   return true;
1483 }
1484 
1485 // ------------------------------------------------------------------
1486 // post_compiled_method_load_event
1487 // new method for install_code() path
1488 // Transfer information from compilation to jvmti
1489 void nmethod::post_compiled_method_load_event() {
1490 
1491   methodOop moop = method();
1492 #ifndef USDT2
1493   HS_DTRACE_PROBE8(hotspot, compiled__method__load,
1494       moop->klass_name()->bytes(),
1495       moop->klass_name()->utf8_length(),
1496       moop->name()->bytes(),
1497       moop->name()->utf8_length(),
1498       moop->signature()->bytes(),
1499       moop->signature()->utf8_length(),
1500       insts_begin(), insts_size());
1501 #else /* USDT2 */
1502   HOTSPOT_COMPILED_METHOD_LOAD(
1503       (char *) moop->klass_name()->bytes(),
1504       moop->klass_name()->utf8_length(),
1505       (char *) moop->name()->bytes(),
1506       moop->name()->utf8_length(),
1507       (char *) moop->signature()->bytes(),
1508       moop->signature()->utf8_length(),
1509       insts_begin(), insts_size());
1510 #endif /* USDT2 */
1511 
1512   if (JvmtiExport::should_post_compiled_method_load() ||
1513       JvmtiExport::should_post_compiled_method_unload()) {
1514     get_and_cache_jmethod_id();
1515   }
1516 
1517   if (JvmtiExport::should_post_compiled_method_load()) {
1518     // Let the Service thread (which is a real Java thread) post the event
1519     MutexLockerEx ml(Service_lock, Mutex::_no_safepoint_check_flag);
1520     JvmtiDeferredEventQueue::enqueue(
1521       JvmtiDeferredEvent::compiled_method_load_event(this));
1522   }
1523 }
1524 
1525 jmethodID nmethod::get_and_cache_jmethod_id() {
1526   if (_jmethod_id == NULL) {
1527     // Cache the jmethod_id since it can no longer be looked up once the
1528     // method itself has been marked for unloading.
1529     _jmethod_id = method()->jmethod_id();
1530   }
1531   return _jmethod_id;
1532 }
1533 
1534 void nmethod::post_compiled_method_unload() {
1535   if (unload_reported()) {
1536     // During unloading we transition to unloaded and then to zombie
1537     // and the unloading is reported during the first transition.
1538     return;
1539   }
1540 
1541   assert(_method != NULL && !is_unloaded(), "just checking");
1542   DTRACE_METHOD_UNLOAD_PROBE(method());
1543 
1544   // If a JVMTI agent has enabled the CompiledMethodUnload event then
1545   // post the event. Sometime later this nmethod will be made a zombie
1546   // by the sweeper but the methodOop will not be valid at that point.
1547   // If the _jmethod_id is null then no load event was ever requested
1548   // so don't bother posting the unload.  The main reason for this is
1549   // that the jmethodID is a weak reference to the methodOop so if
1550   // it's being unloaded there's no way to look it up since the weak
1551   // ref will have been cleared.
1552   if (_jmethod_id != NULL && JvmtiExport::should_post_compiled_method_unload()) {
1553     assert(!unload_reported(), "already unloaded");
1554     JvmtiDeferredEvent event =
1555       JvmtiDeferredEvent::compiled_method_unload_event(this,
1556           _jmethod_id, insts_begin());
1557     if (SafepointSynchronize::is_at_safepoint()) {
1558       // Don't want to take the queueing lock. Add it as pending and
1559       // it will get enqueued later.
1560       JvmtiDeferredEventQueue::add_pending_event(event);
1561     } else {
1562       MutexLockerEx ml(Service_lock, Mutex::_no_safepoint_check_flag);
1563       JvmtiDeferredEventQueue::enqueue(event);
1564     }
1565   }
1566 
1567   // The JVMTI CompiledMethodUnload event can be enabled or disabled at
1568   // any time. As the nmethod is being unloaded now we mark it has
1569   // having the unload event reported - this will ensure that we don't
1570   // attempt to report the event in the unlikely scenario where the
1571   // event is enabled at the time the nmethod is made a zombie.
1572   set_unload_reported();
1573 }
1574 
1575 // This is called at the end of the strong tracing/marking phase of a
1576 // GC to unload an nmethod if it contains otherwise unreachable
1577 // oops.
1578 
1579 void nmethod::do_unloading(BoolObjectClosure* is_alive,
1580                            OopClosure* keep_alive, bool unloading_occurred) {
1581   // Make sure the oop's ready to receive visitors
1582   assert(!is_zombie() && !is_unloaded(),
1583          "should not call follow on zombie or unloaded nmethod");
1584 
1585   // If the method is not entrant then a JMP is plastered over the
1586   // first few bytes.  If an oop in the old code was there, that oop
1587   // should not get GC'd.  Skip the first few bytes of oops on
1588   // not-entrant methods.
1589   address low_boundary = verified_entry_point();
1590   if (is_not_entrant()) {
1591     low_boundary += NativeJump::instruction_size;
1592     // %%% Note:  On SPARC we patch only a 4-byte trap, not a full NativeJump.
1593     // (See comment above.)
1594   }
1595 
1596   // The RedefineClasses() API can cause the class unloading invariant
1597   // to no longer be true. See jvmtiExport.hpp for details.
1598   // Also, leave a debugging breadcrumb in local flag.
1599   bool a_class_was_redefined = JvmtiExport::has_redefined_a_class();
1600   if (a_class_was_redefined) {
1601     // This set of the unloading_occurred flag is done before the
1602     // call to post_compiled_method_unload() so that the unloading
1603     // of this nmethod is reported.
1604     unloading_occurred = true;
1605   }
1606 
1607   // Follow methodOop
1608   if (can_unload(is_alive, keep_alive, (oop*)&_method, unloading_occurred)) {
1609     return;
1610   }
1611 
1612   // Exception cache
1613   ExceptionCache* ec = exception_cache();
1614   while (ec != NULL) {
1615     oop* ex_addr = (oop*)ec->exception_type_addr();
1616     oop ex = *ex_addr;
1617     ExceptionCache* next_ec = ec->next();
1618     if (ex != NULL && !is_alive->do_object_b(ex)) {
1619       assert(!ex->is_compiledICHolder(), "Possible error here");
1620       remove_from_exception_cache(ec);
1621     }
1622     ec = next_ec;
1623   }
1624 
1625   // If class unloading occurred we first iterate over all inline caches and
1626   // clear ICs where the cached oop is referring to an unloaded klass or method.
1627   // The remaining live cached oops will be traversed in the relocInfo::oop_type
1628   // iteration below.
1629   if (unloading_occurred) {
1630     RelocIterator iter(this, low_boundary);
1631     while(iter.next()) {
1632       if (iter.type() == relocInfo::virtual_call_type) {
1633         CompiledIC *ic = CompiledIC_at(iter.reloc());
1634         oop ic_oop = ic->cached_oop();
1635         if (ic_oop != NULL && !is_alive->do_object_b(ic_oop)) {
1636           // The only exception is compiledICHolder oops which may
1637           // yet be marked below. (We check this further below).
1638           if (ic_oop->is_compiledICHolder()) {
1639             compiledICHolderOop cichk_oop = compiledICHolderOop(ic_oop);
1640             if (is_alive->do_object_b(
1641                   cichk_oop->holder_method()->method_holder()) &&
1642                 is_alive->do_object_b(cichk_oop->holder_klass())) {
1643               continue;
1644             }
1645           }
1646           ic->set_to_clean();
1647           assert(ic->cached_oop() == NULL,
1648                  "cached oop in IC should be cleared");
1649         }
1650       }
1651     }
1652   }
1653 
1654   // Compiled code
1655   RelocIterator iter(this, low_boundary);
1656   while (iter.next()) {
1657     if (iter.type() == relocInfo::oop_type) {
1658       oop_Relocation* r = iter.oop_reloc();
1659       // In this loop, we must only traverse those oops directly embedded in
1660       // the code.  Other oops (oop_index>0) are seen as part of scopes_oops.
1661       assert(1 == (r->oop_is_immediate()) +
1662                   (r->oop_addr() >= oops_begin() && r->oop_addr() < oops_end()),
1663              "oop must be found in exactly one place");
1664       if (r->oop_is_immediate() && r->oop_value() != NULL) {
1665         if (can_unload(is_alive, keep_alive, r->oop_addr(), unloading_occurred)) {
1666           return;
1667         }
1668       }
1669     }
1670   }
1671 
1672 
1673   // Scopes
1674   for (oop* p = oops_begin(); p < oops_end(); p++) {
1675     if (*p == Universe::non_oop_word())  continue;  // skip non-oops
1676     if (can_unload(is_alive, keep_alive, p, unloading_occurred)) {
1677       return;
1678     }
1679   }
1680 
1681 #ifndef PRODUCT
1682   // This nmethod was not unloaded; check below that all CompiledICs
1683   // refer to marked oops.
1684   {
1685     RelocIterator iter(this, low_boundary);
1686     while (iter.next()) {
1687       if (iter.type() == relocInfo::virtual_call_type) {
1688          CompiledIC *ic = CompiledIC_at(iter.reloc());
1689          oop ic_oop = ic->cached_oop();
1690          assert(ic_oop == NULL || is_alive->do_object_b(ic_oop),
1691                 "Found unmarked ic_oop in reachable nmethod");
1692        }
1693     }
1694   }
1695 #endif // !PRODUCT
1696 }
1697 
1698 // This method is called twice during GC -- once while
1699 // tracing the "active" nmethods on thread stacks during
1700 // the (strong) marking phase, and then again when walking
1701 // the code cache contents during the weak roots processing
1702 // phase. The two uses are distinguished by means of the
1703 // 'do_strong_roots_only' flag, which is true in the first
1704 // case. We want to walk the weak roots in the nmethod
1705 // only in the second case. The weak roots in the nmethod
1706 // are the oops in the ExceptionCache and the InlineCache
1707 // oops.
1708 void nmethod::oops_do(OopClosure* f, bool do_strong_roots_only) {
1709   // make sure the oops ready to receive visitors
1710   assert(!is_zombie() && !is_unloaded(),
1711          "should not call follow on zombie or unloaded nmethod");
1712 
1713   // If the method is not entrant or zombie then a JMP is plastered over the
1714   // first few bytes.  If an oop in the old code was there, that oop
1715   // should not get GC'd.  Skip the first few bytes of oops on
1716   // not-entrant methods.
1717   address low_boundary = verified_entry_point();
1718   if (is_not_entrant()) {
1719     low_boundary += NativeJump::instruction_size;
1720     // %%% Note:  On SPARC we patch only a 4-byte trap, not a full NativeJump.
1721     // (See comment above.)
1722   }
1723 
1724   // Compiled code
1725   f->do_oop((oop*) &_method);
1726   if (!do_strong_roots_only) {
1727     // weak roots processing phase -- update ExceptionCache oops
1728     ExceptionCache* ec = exception_cache();
1729     while(ec != NULL) {
1730       f->do_oop((oop*)ec->exception_type_addr());
1731       ec = ec->next();
1732     }
1733   } // Else strong roots phase -- skip oops in ExceptionCache
1734 
1735   RelocIterator iter(this, low_boundary);
1736 
1737   while (iter.next()) {
1738     if (iter.type() == relocInfo::oop_type ) {
1739       oop_Relocation* r = iter.oop_reloc();
1740       // In this loop, we must only follow those oops directly embedded in
1741       // the code.  Other oops (oop_index>0) are seen as part of scopes_oops.
1742       assert(1 == (r->oop_is_immediate()) +
1743                    (r->oop_addr() >= oops_begin() && r->oop_addr() < oops_end()),
1744              "oop must be found in exactly one place");
1745       if (r->oop_is_immediate() && r->oop_value() != NULL) {
1746         f->do_oop(r->oop_addr());
1747       }
1748     }
1749   }
1750 
1751   // Scopes
1752   // This includes oop constants not inlined in the code stream.
1753   for (oop* p = oops_begin(); p < oops_end(); p++) {
1754     if (*p == Universe::non_oop_word())  continue;  // skip non-oops
1755     f->do_oop(p);
1756   }
1757 }
1758 
1759 #define NMETHOD_SENTINEL ((nmethod*)badAddress)
1760 
1761 nmethod* volatile nmethod::_oops_do_mark_nmethods;
1762 
1763 // An nmethod is "marked" if its _mark_link is set non-null.
1764 // Even if it is the end of the linked list, it will have a non-null link value,
1765 // as long as it is on the list.
1766 // This code must be MP safe, because it is used from parallel GC passes.
1767 bool nmethod::test_set_oops_do_mark() {
1768   assert(nmethod::oops_do_marking_is_active(), "oops_do_marking_prologue must be called");
1769   nmethod* observed_mark_link = _oops_do_mark_link;
1770   if (observed_mark_link == NULL) {
1771     // Claim this nmethod for this thread to mark.
1772     observed_mark_link = (nmethod*)
1773       Atomic::cmpxchg_ptr(NMETHOD_SENTINEL, &_oops_do_mark_link, NULL);
1774     if (observed_mark_link == NULL) {
1775 
1776       // Atomically append this nmethod (now claimed) to the head of the list:
1777       nmethod* observed_mark_nmethods = _oops_do_mark_nmethods;
1778       for (;;) {
1779         nmethod* required_mark_nmethods = observed_mark_nmethods;
1780         _oops_do_mark_link = required_mark_nmethods;
1781         observed_mark_nmethods = (nmethod*)
1782           Atomic::cmpxchg_ptr(this, &_oops_do_mark_nmethods, required_mark_nmethods);
1783         if (observed_mark_nmethods == required_mark_nmethods)
1784           break;
1785       }
1786       // Mark was clear when we first saw this guy.
1787       NOT_PRODUCT(if (TraceScavenge)  print_on(tty, "oops_do, mark"));
1788       return false;
1789     }
1790   }
1791   // On fall through, another racing thread marked this nmethod before we did.
1792   return true;
1793 }
1794 
1795 void nmethod::oops_do_marking_prologue() {
1796   NOT_PRODUCT(if (TraceScavenge)  tty->print_cr("[oops_do_marking_prologue"));
1797   assert(_oops_do_mark_nmethods == NULL, "must not call oops_do_marking_prologue twice in a row");
1798   // We use cmpxchg_ptr instead of regular assignment here because the user
1799   // may fork a bunch of threads, and we need them all to see the same state.
1800   void* observed = Atomic::cmpxchg_ptr(NMETHOD_SENTINEL, &_oops_do_mark_nmethods, NULL);
1801   guarantee(observed == NULL, "no races in this sequential code");
1802 }
1803 
1804 void nmethod::oops_do_marking_epilogue() {
1805   assert(_oops_do_mark_nmethods != NULL, "must not call oops_do_marking_epilogue twice in a row");
1806   nmethod* cur = _oops_do_mark_nmethods;
1807   while (cur != NMETHOD_SENTINEL) {
1808     assert(cur != NULL, "not NULL-terminated");
1809     nmethod* next = cur->_oops_do_mark_link;
1810     cur->_oops_do_mark_link = NULL;
1811     cur->fix_oop_relocations();
1812     NOT_PRODUCT(if (TraceScavenge)  cur->print_on(tty, "oops_do, unmark"));
1813     cur = next;
1814   }
1815   void* required = _oops_do_mark_nmethods;
1816   void* observed = Atomic::cmpxchg_ptr(NULL, &_oops_do_mark_nmethods, required);
1817   guarantee(observed == required, "no races in this sequential code");
1818   NOT_PRODUCT(if (TraceScavenge)  tty->print_cr("oops_do_marking_epilogue]"));
1819 }
1820 
1821 class DetectScavengeRoot: public OopClosure {
1822   bool     _detected_scavenge_root;
1823 public:
1824   DetectScavengeRoot() : _detected_scavenge_root(false)
1825   { NOT_PRODUCT(_print_nm = NULL); }
1826   bool detected_scavenge_root() { return _detected_scavenge_root; }
1827   virtual void do_oop(oop* p) {
1828     if ((*p) != NULL && (*p)->is_scavengable()) {
1829       NOT_PRODUCT(maybe_print(p));
1830       _detected_scavenge_root = true;
1831     }
1832   }
1833   virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
1834 
1835 #ifndef PRODUCT
1836   nmethod* _print_nm;
1837   void maybe_print(oop* p) {
1838     if (_print_nm == NULL)  return;
1839     if (!_detected_scavenge_root)  _print_nm->print_on(tty, "new scavenge root");
1840     tty->print_cr(""PTR_FORMAT"[offset=%d] detected scavengable oop "PTR_FORMAT" (found at "PTR_FORMAT")",
1841                   _print_nm, (int)((intptr_t)p - (intptr_t)_print_nm),
1842                   (intptr_t)(*p), (intptr_t)p);
1843     (*p)->print();
1844   }
1845 #endif //PRODUCT
1846 };
1847 
1848 bool nmethod::detect_scavenge_root_oops() {
1849   DetectScavengeRoot detect_scavenge_root;
1850   NOT_PRODUCT(if (TraceScavenge)  detect_scavenge_root._print_nm = this);
1851   oops_do(&detect_scavenge_root);
1852   return detect_scavenge_root.detected_scavenge_root();
1853 }
1854 
1855 // Method that knows how to preserve outgoing arguments at call. This method must be
1856 // called with a frame corresponding to a Java invoke
1857 void nmethod::preserve_callee_argument_oops(frame fr, const RegisterMap *reg_map, OopClosure* f) {
1858 #ifndef SHARK
1859   if (!method()->is_native()) {
1860     SimpleScopeDesc ssd(this, fr.pc());
1861     Bytecode_invoke call(ssd.method(), ssd.bci());
1862     // compiled invokedynamic call sites have an implicit receiver at
1863     // resolution time, so make sure it gets GC'ed.
1864     bool has_receiver = !call.is_invokestatic();
1865     Symbol* signature = call.signature();
1866     fr.oops_compiled_arguments_do(signature, has_receiver, reg_map, f);
1867   }
1868 #endif // !SHARK
1869 }
1870 
1871 
1872 oop nmethod::embeddedOop_at(u_char* p) {
1873   RelocIterator iter(this, p, p + 1);
1874   while (iter.next())
1875     if (iter.type() == relocInfo::oop_type) {
1876       return iter.oop_reloc()->oop_value();
1877     }
1878   return NULL;
1879 }
1880 
1881 
1882 inline bool includes(void* p, void* from, void* to) {
1883   return from <= p && p < to;
1884 }
1885 
1886 
1887 void nmethod::copy_scopes_pcs(PcDesc* pcs, int count) {
1888   assert(count >= 2, "must be sentinel values, at least");
1889 
1890 #ifdef ASSERT
1891   // must be sorted and unique; we do a binary search in find_pc_desc()
1892   int prev_offset = pcs[0].pc_offset();
1893   assert(prev_offset == PcDesc::lower_offset_limit,
1894          "must start with a sentinel");
1895   for (int i = 1; i < count; i++) {
1896     int this_offset = pcs[i].pc_offset();
1897     assert(this_offset > prev_offset, "offsets must be sorted");
1898     prev_offset = this_offset;
1899   }
1900   assert(prev_offset == PcDesc::upper_offset_limit,
1901          "must end with a sentinel");
1902 #endif //ASSERT
1903 
1904   // Search for MethodHandle invokes and tag the nmethod.
1905   for (int i = 0; i < count; i++) {
1906     if (pcs[i].is_method_handle_invoke()) {
1907       set_has_method_handle_invokes(true);
1908       break;
1909     }
1910   }
1911   assert(has_method_handle_invokes() == (_deoptimize_mh_offset != -1), "must have deopt mh handler");
1912 
1913   int size = count * sizeof(PcDesc);
1914   assert(scopes_pcs_size() >= size, "oob");
1915   memcpy(scopes_pcs_begin(), pcs, size);
1916 
1917   // Adjust the final sentinel downward.
1918   PcDesc* last_pc = &scopes_pcs_begin()[count-1];
1919   assert(last_pc->pc_offset() == PcDesc::upper_offset_limit, "sanity");
1920   last_pc->set_pc_offset(content_size() + 1);
1921   for (; last_pc + 1 < scopes_pcs_end(); last_pc += 1) {
1922     // Fill any rounding gaps with copies of the last record.
1923     last_pc[1] = last_pc[0];
1924   }
1925   // The following assert could fail if sizeof(PcDesc) is not
1926   // an integral multiple of oopSize (the rounding term).
1927   // If it fails, change the logic to always allocate a multiple
1928   // of sizeof(PcDesc), and fill unused words with copies of *last_pc.
1929   assert(last_pc + 1 == scopes_pcs_end(), "must match exactly");
1930 }
1931 
1932 void nmethod::copy_scopes_data(u_char* buffer, int size) {
1933   assert(scopes_data_size() >= size, "oob");
1934   memcpy(scopes_data_begin(), buffer, size);
1935 }
1936 
1937 
1938 #ifdef ASSERT
1939 static PcDesc* linear_search(nmethod* nm, int pc_offset, bool approximate) {
1940   PcDesc* lower = nm->scopes_pcs_begin();
1941   PcDesc* upper = nm->scopes_pcs_end();
1942   lower += 1; // exclude initial sentinel
1943   PcDesc* res = NULL;
1944   for (PcDesc* p = lower; p < upper; p++) {
1945     NOT_PRODUCT(--nmethod_stats.pc_desc_tests);  // don't count this call to match_desc
1946     if (match_desc(p, pc_offset, approximate)) {
1947       if (res == NULL)
1948         res = p;
1949       else
1950         res = (PcDesc*) badAddress;
1951     }
1952   }
1953   return res;
1954 }
1955 #endif
1956 
1957 
1958 // Finds a PcDesc with real-pc equal to "pc"
1959 PcDesc* nmethod::find_pc_desc_internal(address pc, bool approximate) {
1960   address base_address = code_begin();
1961   if ((pc < base_address) ||
1962       (pc - base_address) >= (ptrdiff_t) PcDesc::upper_offset_limit) {
1963     return NULL;  // PC is wildly out of range
1964   }
1965   int pc_offset = (int) (pc - base_address);
1966 
1967   // Check the PcDesc cache if it contains the desired PcDesc
1968   // (This as an almost 100% hit rate.)
1969   PcDesc* res = _pc_desc_cache.find_pc_desc(pc_offset, approximate);
1970   if (res != NULL) {
1971     assert(res == linear_search(this, pc_offset, approximate), "cache ok");
1972     return res;
1973   }
1974 
1975   // Fallback algorithm: quasi-linear search for the PcDesc
1976   // Find the last pc_offset less than the given offset.
1977   // The successor must be the required match, if there is a match at all.
1978   // (Use a fixed radix to avoid expensive affine pointer arithmetic.)
1979   PcDesc* lower = scopes_pcs_begin();
1980   PcDesc* upper = scopes_pcs_end();
1981   upper -= 1; // exclude final sentinel
1982   if (lower >= upper)  return NULL;  // native method; no PcDescs at all
1983 
1984 #define assert_LU_OK \
1985   /* invariant on lower..upper during the following search: */ \
1986   assert(lower->pc_offset() <  pc_offset, "sanity"); \
1987   assert(upper->pc_offset() >= pc_offset, "sanity")
1988   assert_LU_OK;
1989 
1990   // Use the last successful return as a split point.
1991   PcDesc* mid = _pc_desc_cache.last_pc_desc();
1992   NOT_PRODUCT(++nmethod_stats.pc_desc_searches);
1993   if (mid->pc_offset() < pc_offset) {
1994     lower = mid;
1995   } else {
1996     upper = mid;
1997   }
1998 
1999   // Take giant steps at first (4096, then 256, then 16, then 1)
2000   const int LOG2_RADIX = 4 /*smaller steps in debug mode:*/ debug_only(-1);
2001   const int RADIX = (1 << LOG2_RADIX);
2002   for (int step = (1 << (LOG2_RADIX*3)); step > 1; step >>= LOG2_RADIX) {
2003     while ((mid = lower + step) < upper) {
2004       assert_LU_OK;
2005       NOT_PRODUCT(++nmethod_stats.pc_desc_searches);
2006       if (mid->pc_offset() < pc_offset) {
2007         lower = mid;
2008       } else {
2009         upper = mid;
2010         break;
2011       }
2012     }
2013     assert_LU_OK;
2014   }
2015 
2016   // Sneak up on the value with a linear search of length ~16.
2017   while (true) {
2018     assert_LU_OK;
2019     mid = lower + 1;
2020     NOT_PRODUCT(++nmethod_stats.pc_desc_searches);
2021     if (mid->pc_offset() < pc_offset) {
2022       lower = mid;
2023     } else {
2024       upper = mid;
2025       break;
2026     }
2027   }
2028 #undef assert_LU_OK
2029 
2030   if (match_desc(upper, pc_offset, approximate)) {
2031     assert(upper == linear_search(this, pc_offset, approximate), "search ok");
2032     _pc_desc_cache.add_pc_desc(upper);
2033     return upper;
2034   } else {
2035     assert(NULL == linear_search(this, pc_offset, approximate), "search ok");
2036     return NULL;
2037   }
2038 }
2039 
2040 
2041 bool nmethod::check_all_dependencies() {
2042   bool found_check = false;
2043   // wholesale check of all dependencies
2044   for (Dependencies::DepStream deps(this); deps.next(); ) {
2045     if (deps.check_dependency() != NULL) {
2046       found_check = true;
2047       NOT_DEBUG(break);
2048     }
2049   }
2050   return found_check;  // tell caller if we found anything
2051 }
2052 
2053 bool nmethod::check_dependency_on(DepChange& changes) {
2054   // What has happened:
2055   // 1) a new class dependee has been added
2056   // 2) dependee and all its super classes have been marked
2057   bool found_check = false;  // set true if we are upset
2058   for (Dependencies::DepStream deps(this); deps.next(); ) {
2059     // Evaluate only relevant dependencies.
2060     if (deps.spot_check_dependency_at(changes) != NULL) {
2061       found_check = true;
2062       NOT_DEBUG(break);
2063     }
2064   }
2065   return found_check;
2066 }
2067 
2068 bool nmethod::is_evol_dependent_on(klassOop dependee) {
2069   instanceKlass *dependee_ik = instanceKlass::cast(dependee);
2070   objArrayOop dependee_methods = dependee_ik->methods();
2071   for (Dependencies::DepStream deps(this); deps.next(); ) {
2072     if (deps.type() == Dependencies::evol_method) {
2073       methodOop method = deps.method_argument(0);
2074       for (int j = 0; j < dependee_methods->length(); j++) {
2075         if ((methodOop) dependee_methods->obj_at(j) == method) {
2076           // RC_TRACE macro has an embedded ResourceMark
2077           RC_TRACE(0x01000000,
2078             ("Found evol dependency of nmethod %s.%s(%s) compile_id=%d on method %s.%s(%s)",
2079             _method->method_holder()->klass_part()->external_name(),
2080             _method->name()->as_C_string(),
2081             _method->signature()->as_C_string(), compile_id(),
2082             method->method_holder()->klass_part()->external_name(),
2083             method->name()->as_C_string(),
2084             method->signature()->as_C_string()));
2085           if (TraceDependencies || LogCompilation)
2086             deps.log_dependency(dependee);
2087           return true;
2088         }
2089       }
2090     }
2091   }
2092   return false;
2093 }
2094 
2095 // Called from mark_for_deoptimization, when dependee is invalidated.
2096 bool nmethod::is_dependent_on_method(methodOop dependee) {
2097   for (Dependencies::DepStream deps(this); deps.next(); ) {
2098     if (deps.type() != Dependencies::evol_method)
2099       continue;
2100     methodOop method = deps.method_argument(0);
2101     if (method == dependee) return true;
2102   }
2103   return false;
2104 }
2105 
2106 
2107 bool nmethod::is_patchable_at(address instr_addr) {
2108   assert(insts_contains(instr_addr), "wrong nmethod used");
2109   if (is_zombie()) {
2110     // a zombie may never be patched
2111     return false;
2112   }
2113   return true;
2114 }
2115 
2116 
2117 address nmethod::continuation_for_implicit_exception(address pc) {
2118   // Exception happened outside inline-cache check code => we are inside
2119   // an active nmethod => use cpc to determine a return address
2120   int exception_offset = pc - code_begin();
2121   int cont_offset = ImplicitExceptionTable(this).at( exception_offset );
2122 #ifdef ASSERT
2123   if (cont_offset == 0) {
2124     Thread* thread = ThreadLocalStorage::get_thread_slow();
2125     ResetNoHandleMark rnm; // Might be called from LEAF/QUICK ENTRY
2126     HandleMark hm(thread);
2127     ResourceMark rm(thread);
2128     CodeBlob* cb = CodeCache::find_blob(pc);
2129     assert(cb != NULL && cb == this, "");
2130     tty->print_cr("implicit exception happened at " INTPTR_FORMAT, pc);
2131     print();
2132     method()->print_codes();
2133     print_code();
2134     print_pcs();
2135   }
2136 #endif
2137   if (cont_offset == 0) {
2138     // Let the normal error handling report the exception
2139     return NULL;
2140   }
2141   return code_begin() + cont_offset;
2142 }
2143 
2144 
2145 
2146 void nmethod_init() {
2147   // make sure you didn't forget to adjust the filler fields
2148   assert(sizeof(nmethod) % oopSize == 0, "nmethod size must be multiple of a word");
2149 }
2150 
2151 
2152 //-------------------------------------------------------------------------------------------
2153 
2154 
2155 // QQQ might we make this work from a frame??
2156 nmethodLocker::nmethodLocker(address pc) {
2157   CodeBlob* cb = CodeCache::find_blob(pc);
2158   guarantee(cb != NULL && cb->is_nmethod(), "bad pc for a nmethod found");
2159   _nm = (nmethod*)cb;
2160   lock_nmethod(_nm);
2161 }
2162 
2163 // Only JvmtiDeferredEvent::compiled_method_unload_event()
2164 // should pass zombie_ok == true.
2165 void nmethodLocker::lock_nmethod(nmethod* nm, bool zombie_ok) {
2166   if (nm == NULL)  return;
2167   Atomic::inc(&nm->_lock_count);
2168   guarantee(zombie_ok || !nm->is_zombie(), "cannot lock a zombie method");
2169 }
2170 
2171 void nmethodLocker::unlock_nmethod(nmethod* nm) {
2172   if (nm == NULL)  return;
2173   Atomic::dec(&nm->_lock_count);
2174   guarantee(nm->_lock_count >= 0, "unmatched nmethod lock/unlock");
2175 }
2176 
2177 
2178 // -----------------------------------------------------------------------------
2179 // nmethod::get_deopt_original_pc
2180 //
2181 // Return the original PC for the given PC if:
2182 // (a) the given PC belongs to a nmethod and
2183 // (b) it is a deopt PC
2184 address nmethod::get_deopt_original_pc(const frame* fr) {
2185   if (fr->cb() == NULL)  return NULL;
2186 
2187   nmethod* nm = fr->cb()->as_nmethod_or_null();
2188   if (nm != NULL && nm->is_deopt_pc(fr->pc()))
2189     return nm->get_original_pc(fr);
2190 
2191   return NULL;
2192 }
2193 
2194 
2195 // -----------------------------------------------------------------------------
2196 // MethodHandle
2197 
2198 bool nmethod::is_method_handle_return(address return_pc) {
2199   if (!has_method_handle_invokes())  return false;
2200   PcDesc* pd = pc_desc_at(return_pc);
2201   if (pd == NULL)
2202     return false;
2203   return pd->is_method_handle_invoke();
2204 }
2205 
2206 
2207 // -----------------------------------------------------------------------------
2208 // Verification
2209 
2210 class VerifyOopsClosure: public OopClosure {
2211   nmethod* _nm;
2212   bool     _ok;
2213 public:
2214   VerifyOopsClosure(nmethod* nm) : _nm(nm), _ok(true) { }
2215   bool ok() { return _ok; }
2216   virtual void do_oop(oop* p) {
2217     if ((*p) == NULL || (*p)->is_oop())  return;
2218     if (_ok) {
2219       _nm->print_nmethod(true);
2220       _ok = false;
2221     }
2222     tty->print_cr("*** non-oop "PTR_FORMAT" found at "PTR_FORMAT" (offset %d)",
2223                   (intptr_t)(*p), (intptr_t)p, (int)((intptr_t)p - (intptr_t)_nm));
2224   }
2225   virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
2226 };
2227 
2228 void nmethod::verify() {
2229 
2230   // Hmm. OSR methods can be deopted but not marked as zombie or not_entrant
2231   // seems odd.
2232 
2233   if( is_zombie() || is_not_entrant() )
2234     return;
2235 
2236   // Make sure all the entry points are correctly aligned for patching.
2237   NativeJump::check_verified_entry_alignment(entry_point(), verified_entry_point());
2238 
2239   assert(method()->is_oop(), "must be valid");
2240 
2241   ResourceMark rm;
2242 
2243   if (!CodeCache::contains(this)) {
2244     fatal(err_msg("nmethod at " INTPTR_FORMAT " not in zone", this));
2245   }
2246 
2247   if(is_native_method() )
2248     return;
2249 
2250   nmethod* nm = CodeCache::find_nmethod(verified_entry_point());
2251   if (nm != this) {
2252     fatal(err_msg("findNMethod did not find this nmethod (" INTPTR_FORMAT ")",
2253                   this));
2254   }
2255 
2256   for (PcDesc* p = scopes_pcs_begin(); p < scopes_pcs_end(); p++) {
2257     if (! p->verify(this)) {
2258       tty->print_cr("\t\tin nmethod at " INTPTR_FORMAT " (pcs)", this);
2259     }
2260   }
2261 
2262   VerifyOopsClosure voc(this);
2263   oops_do(&voc);
2264   assert(voc.ok(), "embedded oops must be OK");
2265   verify_scavenge_root_oops();
2266 
2267   verify_scopes();
2268 }
2269 
2270 
2271 void nmethod::verify_interrupt_point(address call_site) {
2272   // This code does not work in release mode since
2273   // owns_lock only is available in debug mode.
2274   CompiledIC* ic = NULL;
2275   Thread *cur = Thread::current();
2276   if (CompiledIC_lock->owner() == cur ||
2277       ((cur->is_VM_thread() || cur->is_ConcurrentGC_thread()) &&
2278        SafepointSynchronize::is_at_safepoint())) {
2279     ic = CompiledIC_at(call_site);
2280     CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops());
2281   } else {
2282     MutexLocker ml_verify (CompiledIC_lock);
2283     ic = CompiledIC_at(call_site);
2284   }
2285   PcDesc* pd = pc_desc_at(ic->end_of_call());
2286   assert(pd != NULL, "PcDesc must exist");
2287   for (ScopeDesc* sd = new ScopeDesc(this, pd->scope_decode_offset(),
2288                                      pd->obj_decode_offset(), pd->should_reexecute(),
2289                                      pd->return_oop());
2290        !sd->is_top(); sd = sd->sender()) {
2291     sd->verify();
2292   }
2293 }
2294 
2295 void nmethod::verify_scopes() {
2296   if( !method() ) return;       // Runtime stubs have no scope
2297   if (method()->is_native()) return; // Ignore stub methods.
2298   // iterate through all interrupt point
2299   // and verify the debug information is valid.
2300   RelocIterator iter((nmethod*)this);
2301   while (iter.next()) {
2302     address stub = NULL;
2303     switch (iter.type()) {
2304       case relocInfo::virtual_call_type:
2305         verify_interrupt_point(iter.addr());
2306         break;
2307       case relocInfo::opt_virtual_call_type:
2308         stub = iter.opt_virtual_call_reloc()->static_stub();
2309         verify_interrupt_point(iter.addr());
2310         break;
2311       case relocInfo::static_call_type:
2312         stub = iter.static_call_reloc()->static_stub();
2313         //verify_interrupt_point(iter.addr());
2314         break;
2315       case relocInfo::runtime_call_type:
2316         address destination = iter.reloc()->value();
2317         // Right now there is no way to find out which entries support
2318         // an interrupt point.  It would be nice if we had this
2319         // information in a table.
2320         break;
2321     }
2322     assert(stub == NULL || stub_contains(stub), "static call stub outside stub section");
2323   }
2324 }
2325 
2326 
2327 // -----------------------------------------------------------------------------
2328 // Non-product code
2329 #ifndef PRODUCT
2330 
2331 class DebugScavengeRoot: public OopClosure {
2332   nmethod* _nm;
2333   bool     _ok;
2334 public:
2335   DebugScavengeRoot(nmethod* nm) : _nm(nm), _ok(true) { }
2336   bool ok() { return _ok; }
2337   virtual void do_oop(oop* p) {
2338     if ((*p) == NULL || !(*p)->is_scavengable())  return;
2339     if (_ok) {
2340       _nm->print_nmethod(true);
2341       _ok = false;
2342     }
2343     tty->print_cr("*** scavengable oop "PTR_FORMAT" found at "PTR_FORMAT" (offset %d)",
2344                   (intptr_t)(*p), (intptr_t)p, (int)((intptr_t)p - (intptr_t)_nm));
2345     (*p)->print();
2346   }
2347   virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
2348 };
2349 
2350 void nmethod::verify_scavenge_root_oops() {
2351   if (!on_scavenge_root_list()) {
2352     // Actually look inside, to verify the claim that it's clean.
2353     DebugScavengeRoot debug_scavenge_root(this);
2354     oops_do(&debug_scavenge_root);
2355     if (!debug_scavenge_root.ok())
2356       fatal("found an unadvertised bad scavengable oop in the code cache");
2357   }
2358   assert(scavenge_root_not_marked(), "");
2359 }
2360 
2361 #endif // PRODUCT
2362 
2363 // Printing operations
2364 
2365 void nmethod::print() const {
2366   ResourceMark rm;
2367   ttyLocker ttyl;   // keep the following output all in one block
2368 
2369   tty->print("Compiled method ");
2370 
2371   if (is_compiled_by_c1()) {
2372     tty->print("(c1) ");
2373   } else if (is_compiled_by_c2()) {
2374     tty->print("(c2) ");
2375   } else if (is_compiled_by_shark()) {
2376     tty->print("(shark) ");
2377   } else {
2378     tty->print("(nm) ");
2379   }
2380 
2381   print_on(tty, NULL);
2382 
2383   if (WizardMode) {
2384     tty->print("((nmethod*) "INTPTR_FORMAT ") ", this);
2385     tty->print(" for method " INTPTR_FORMAT , (address)method());
2386     tty->print(" { ");
2387     if (is_in_use())      tty->print("in_use ");
2388     if (is_not_entrant()) tty->print("not_entrant ");
2389     if (is_zombie())      tty->print("zombie ");
2390     if (is_unloaded())    tty->print("unloaded ");
2391     if (on_scavenge_root_list())  tty->print("scavenge_root ");
2392     tty->print_cr("}:");
2393   }
2394   if (size              () > 0) tty->print_cr(" total in heap  [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2395                                               (address)this,
2396                                               (address)this + size(),
2397                                               size());
2398   if (relocation_size   () > 0) tty->print_cr(" relocation     [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2399                                               relocation_begin(),
2400                                               relocation_end(),
2401                                               relocation_size());
2402   if (consts_size       () > 0) tty->print_cr(" constants      [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2403                                               consts_begin(),
2404                                               consts_end(),
2405                                               consts_size());
2406   if (insts_size        () > 0) tty->print_cr(" main code      [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2407                                               insts_begin(),
2408                                               insts_end(),
2409                                               insts_size());
2410   if (stub_size         () > 0) tty->print_cr(" stub code      [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2411                                               stub_begin(),
2412                                               stub_end(),
2413                                               stub_size());
2414   if (oops_size         () > 0) tty->print_cr(" oops           [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2415                                               oops_begin(),
2416                                               oops_end(),
2417                                               oops_size());
2418   if (scopes_data_size  () > 0) tty->print_cr(" scopes data    [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2419                                               scopes_data_begin(),
2420                                               scopes_data_end(),
2421                                               scopes_data_size());
2422   if (scopes_pcs_size   () > 0) tty->print_cr(" scopes pcs     [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2423                                               scopes_pcs_begin(),
2424                                               scopes_pcs_end(),
2425                                               scopes_pcs_size());
2426   if (dependencies_size () > 0) tty->print_cr(" dependencies   [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2427                                               dependencies_begin(),
2428                                               dependencies_end(),
2429                                               dependencies_size());
2430   if (handler_table_size() > 0) tty->print_cr(" handler table  [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2431                                               handler_table_begin(),
2432                                               handler_table_end(),
2433                                               handler_table_size());
2434   if (nul_chk_table_size() > 0) tty->print_cr(" nul chk table  [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2435                                               nul_chk_table_begin(),
2436                                               nul_chk_table_end(),
2437                                               nul_chk_table_size());
2438 }
2439 
2440 void nmethod::print_code() {
2441   HandleMark hm;
2442   ResourceMark m;
2443   Disassembler::decode(this);
2444 }
2445 
2446 
2447 #ifndef PRODUCT
2448 
2449 void nmethod::print_scopes() {
2450   // Find the first pc desc for all scopes in the code and print it.
2451   ResourceMark rm;
2452   for (PcDesc* p = scopes_pcs_begin(); p < scopes_pcs_end(); p++) {
2453     if (p->scope_decode_offset() == DebugInformationRecorder::serialized_null)
2454       continue;
2455 
2456     ScopeDesc* sd = scope_desc_at(p->real_pc(this));
2457     sd->print_on(tty, p);
2458   }
2459 }
2460 
2461 void nmethod::print_dependencies() {
2462   ResourceMark rm;
2463   ttyLocker ttyl;   // keep the following output all in one block
2464   tty->print_cr("Dependencies:");
2465   for (Dependencies::DepStream deps(this); deps.next(); ) {
2466     deps.print_dependency();
2467     klassOop ctxk = deps.context_type();
2468     if (ctxk != NULL) {
2469       Klass* k = Klass::cast(ctxk);
2470       if (k->oop_is_instance() && ((instanceKlass*)k)->is_dependent_nmethod(this)) {
2471         tty->print_cr("   [nmethod<=klass]%s", k->external_name());
2472       }
2473     }
2474     deps.log_dependency();  // put it into the xml log also
2475   }
2476 }
2477 
2478 
2479 void nmethod::print_relocations() {
2480   ResourceMark m;       // in case methods get printed via the debugger
2481   tty->print_cr("relocations:");
2482   RelocIterator iter(this);
2483   iter.print();
2484   if (UseRelocIndex) {
2485     jint* index_end   = (jint*)relocation_end() - 1;
2486     jint  index_size  = *index_end;
2487     jint* index_start = (jint*)( (address)index_end - index_size );
2488     tty->print_cr("    index @" INTPTR_FORMAT ": index_size=%d", index_start, index_size);
2489     if (index_size > 0) {
2490       jint* ip;
2491       for (ip = index_start; ip+2 <= index_end; ip += 2)
2492         tty->print_cr("  (%d %d) addr=" INTPTR_FORMAT " @" INTPTR_FORMAT,
2493                       ip[0],
2494                       ip[1],
2495                       header_end()+ip[0],
2496                       relocation_begin()-1+ip[1]);
2497       for (; ip < index_end; ip++)
2498         tty->print_cr("  (%d ?)", ip[0]);
2499       tty->print_cr("          @" INTPTR_FORMAT ": index_size=%d", ip, *ip++);
2500       tty->print_cr("reloc_end @" INTPTR_FORMAT ":", ip);
2501     }
2502   }
2503 }
2504 
2505 
2506 void nmethod::print_pcs() {
2507   ResourceMark m;       // in case methods get printed via debugger
2508   tty->print_cr("pc-bytecode offsets:");
2509   for (PcDesc* p = scopes_pcs_begin(); p < scopes_pcs_end(); p++) {
2510     p->print(this);
2511   }
2512 }
2513 
2514 #endif // PRODUCT
2515 
2516 const char* nmethod::reloc_string_for(u_char* begin, u_char* end) {
2517   RelocIterator iter(this, begin, end);
2518   bool have_one = false;
2519   while (iter.next()) {
2520     have_one = true;
2521     switch (iter.type()) {
2522         case relocInfo::none:                  return "no_reloc";
2523         case relocInfo::oop_type: {
2524           stringStream st;
2525           oop_Relocation* r = iter.oop_reloc();
2526           oop obj = r->oop_value();
2527           st.print("oop(");
2528           if (obj == NULL) st.print("NULL");
2529           else obj->print_value_on(&st);
2530           st.print(")");
2531           return st.as_string();
2532         }
2533         case relocInfo::virtual_call_type:     return "virtual_call";
2534         case relocInfo::opt_virtual_call_type: return "optimized virtual_call";
2535         case relocInfo::static_call_type:      return "static_call";
2536         case relocInfo::static_stub_type:      return "static_stub";
2537         case relocInfo::runtime_call_type:     return "runtime_call";
2538         case relocInfo::external_word_type:    return "external_word";
2539         case relocInfo::internal_word_type:    return "internal_word";
2540         case relocInfo::section_word_type:     return "section_word";
2541         case relocInfo::poll_type:             return "poll";
2542         case relocInfo::poll_return_type:      return "poll_return";
2543         case relocInfo::type_mask:             return "type_bit_mask";
2544     }
2545   }
2546   return have_one ? "other" : NULL;
2547 }
2548 
2549 // Return a the last scope in (begin..end]
2550 ScopeDesc* nmethod::scope_desc_in(address begin, address end) {
2551   PcDesc* p = pc_desc_near(begin+1);
2552   if (p != NULL && p->real_pc(this) <= end) {
2553     return new ScopeDesc(this, p->scope_decode_offset(),
2554                          p->obj_decode_offset(), p->should_reexecute(),
2555                          p->return_oop());
2556   }
2557   return NULL;
2558 }
2559 
2560 void nmethod::print_nmethod_labels(outputStream* stream, address block_begin) {
2561   if (block_begin == entry_point())             stream->print_cr("[Entry Point]");
2562   if (block_begin == verified_entry_point())    stream->print_cr("[Verified Entry Point]");
2563   if (block_begin == exception_begin())         stream->print_cr("[Exception Handler]");
2564   if (block_begin == stub_begin())              stream->print_cr("[Stub Code]");
2565   if (block_begin == deopt_handler_begin())     stream->print_cr("[Deopt Handler Code]");
2566 
2567   if (has_method_handle_invokes())
2568     if (block_begin == deopt_mh_handler_begin())  stream->print_cr("[Deopt MH Handler Code]");
2569 
2570   if (block_begin == consts_begin())            stream->print_cr("[Constants]");
2571 
2572   if (block_begin == entry_point()) {
2573     methodHandle m = method();
2574     if (m.not_null()) {
2575       stream->print("  # ");
2576       m->print_value_on(stream);
2577       stream->cr();
2578     }
2579     if (m.not_null() && !is_osr_method()) {
2580       ResourceMark rm;
2581       int sizeargs = m->size_of_parameters();
2582       BasicType* sig_bt = NEW_RESOURCE_ARRAY(BasicType, sizeargs);
2583       VMRegPair* regs   = NEW_RESOURCE_ARRAY(VMRegPair, sizeargs);
2584       {
2585         int sig_index = 0;
2586         if (!m->is_static())
2587           sig_bt[sig_index++] = T_OBJECT; // 'this'
2588         for (SignatureStream ss(m->signature()); !ss.at_return_type(); ss.next()) {
2589           BasicType t = ss.type();
2590           sig_bt[sig_index++] = t;
2591           if (type2size[t] == 2) {
2592             sig_bt[sig_index++] = T_VOID;
2593           } else {
2594             assert(type2size[t] == 1, "size is 1 or 2");
2595           }
2596         }
2597         assert(sig_index == sizeargs, "");
2598       }
2599       const char* spname = "sp"; // make arch-specific?
2600       intptr_t out_preserve = SharedRuntime::java_calling_convention(sig_bt, regs, sizeargs, false);
2601       int stack_slot_offset = this->frame_size() * wordSize;
2602       int tab1 = 14, tab2 = 24;
2603       int sig_index = 0;
2604       int arg_index = (m->is_static() ? 0 : -1);
2605       bool did_old_sp = false;
2606       for (SignatureStream ss(m->signature()); !ss.at_return_type(); ) {
2607         bool at_this = (arg_index == -1);
2608         bool at_old_sp = false;
2609         BasicType t = (at_this ? T_OBJECT : ss.type());
2610         assert(t == sig_bt[sig_index], "sigs in sync");
2611         if (at_this)
2612           stream->print("  # this: ");
2613         else
2614           stream->print("  # parm%d: ", arg_index);
2615         stream->move_to(tab1);
2616         VMReg fst = regs[sig_index].first();
2617         VMReg snd = regs[sig_index].second();
2618         if (fst->is_reg()) {
2619           stream->print("%s", fst->name());
2620           if (snd->is_valid())  {
2621             stream->print(":%s", snd->name());
2622           }
2623         } else if (fst->is_stack()) {
2624           int offset = fst->reg2stack() * VMRegImpl::stack_slot_size + stack_slot_offset;
2625           if (offset == stack_slot_offset)  at_old_sp = true;
2626           stream->print("[%s+0x%x]", spname, offset);
2627         } else {
2628           stream->print("reg%d:%d??", (int)(intptr_t)fst, (int)(intptr_t)snd);
2629         }
2630         stream->print(" ");
2631         stream->move_to(tab2);
2632         stream->print("= ");
2633         if (at_this) {
2634           m->method_holder()->print_value_on(stream);
2635         } else {
2636           bool did_name = false;
2637           if (!at_this && ss.is_object()) {
2638             Symbol* name = ss.as_symbol_or_null();
2639             if (name != NULL) {
2640               name->print_value_on(stream);
2641               did_name = true;
2642             }
2643           }
2644           if (!did_name)
2645             stream->print("%s", type2name(t));
2646         }
2647         if (at_old_sp) {
2648           stream->print("  (%s of caller)", spname);
2649           did_old_sp = true;
2650         }
2651         stream->cr();
2652         sig_index += type2size[t];
2653         arg_index += 1;
2654         if (!at_this)  ss.next();
2655       }
2656       if (!did_old_sp) {
2657         stream->print("  # ");
2658         stream->move_to(tab1);
2659         stream->print("[%s+0x%x]", spname, stack_slot_offset);
2660         stream->print("  (%s of caller)", spname);
2661         stream->cr();
2662       }
2663     }
2664   }
2665 }
2666 
2667 void nmethod::print_code_comment_on(outputStream* st, int column, u_char* begin, u_char* end) {
2668   // First, find an oopmap in (begin, end].
2669   // We use the odd half-closed interval so that oop maps and scope descs
2670   // which are tied to the byte after a call are printed with the call itself.
2671   address base = code_begin();
2672   OopMapSet* oms = oop_maps();
2673   if (oms != NULL) {
2674     for (int i = 0, imax = oms->size(); i < imax; i++) {
2675       OopMap* om = oms->at(i);
2676       address pc = base + om->offset();
2677       if (pc > begin) {
2678         if (pc <= end) {
2679           st->move_to(column);
2680           st->print("; ");
2681           om->print_on(st);
2682         }
2683         break;
2684       }
2685     }
2686   }
2687 
2688   // Print any debug info present at this pc.
2689   ScopeDesc* sd  = scope_desc_in(begin, end);
2690   if (sd != NULL) {
2691     st->move_to(column);
2692     if (sd->bci() == SynchronizationEntryBCI) {
2693       st->print(";*synchronization entry");
2694     } else {
2695       if (sd->method().is_null()) {
2696         st->print("method is NULL");
2697       } else if (sd->method()->is_native()) {
2698         st->print("method is native");
2699       } else {
2700         Bytecodes::Code bc = sd->method()->java_code_at(sd->bci());
2701         st->print(";*%s", Bytecodes::name(bc));
2702         switch (bc) {
2703         case Bytecodes::_invokevirtual:
2704         case Bytecodes::_invokespecial:
2705         case Bytecodes::_invokestatic:
2706         case Bytecodes::_invokeinterface:
2707           {
2708             Bytecode_invoke invoke(sd->method(), sd->bci());
2709             st->print(" ");
2710             if (invoke.name() != NULL)
2711               invoke.name()->print_symbol_on(st);
2712             else
2713               st->print("<UNKNOWN>");
2714             break;
2715           }
2716         case Bytecodes::_getfield:
2717         case Bytecodes::_putfield:
2718         case Bytecodes::_getstatic:
2719         case Bytecodes::_putstatic:
2720           {
2721             Bytecode_field field(sd->method(), sd->bci());
2722             st->print(" ");
2723             if (field.name() != NULL)
2724               field.name()->print_symbol_on(st);
2725             else
2726               st->print("<UNKNOWN>");
2727           }
2728         }
2729       }
2730     }
2731 
2732     // Print all scopes
2733     for (;sd != NULL; sd = sd->sender()) {
2734       st->move_to(column);
2735       st->print("; -");
2736       if (sd->method().is_null()) {
2737         st->print("method is NULL");
2738       } else {
2739         sd->method()->print_short_name(st);
2740       }
2741       int lineno = sd->method()->line_number_from_bci(sd->bci());
2742       if (lineno != -1) {
2743         st->print("@%d (line %d)", sd->bci(), lineno);
2744       } else {
2745         st->print("@%d", sd->bci());
2746       }
2747       st->cr();
2748     }
2749   }
2750 
2751   // Print relocation information
2752   const char* str = reloc_string_for(begin, end);
2753   if (str != NULL) {
2754     if (sd != NULL) st->cr();
2755     st->move_to(column);
2756     st->print(";   {%s}", str);
2757   }
2758   int cont_offset = ImplicitExceptionTable(this).at(begin - code_begin());
2759   if (cont_offset != 0) {
2760     st->move_to(column);
2761     st->print("; implicit exception: dispatches to " INTPTR_FORMAT, code_begin() + cont_offset);
2762   }
2763 
2764 }
2765 
2766 #ifndef PRODUCT
2767 
2768 void nmethod::print_value_on(outputStream* st) const {
2769   st->print("nmethod");
2770   print_on(st, NULL);
2771 }
2772 
2773 void nmethod::print_calls(outputStream* st) {
2774   RelocIterator iter(this);
2775   while (iter.next()) {
2776     switch (iter.type()) {
2777     case relocInfo::virtual_call_type:
2778     case relocInfo::opt_virtual_call_type: {
2779       VerifyMutexLocker mc(CompiledIC_lock);
2780       CompiledIC_at(iter.reloc())->print();
2781       break;
2782     }
2783     case relocInfo::static_call_type:
2784       st->print_cr("Static call at " INTPTR_FORMAT, iter.reloc()->addr());
2785       compiledStaticCall_at(iter.reloc())->print();
2786       break;
2787     }
2788   }
2789 }
2790 
2791 void nmethod::print_handler_table() {
2792   ExceptionHandlerTable(this).print();
2793 }
2794 
2795 void nmethod::print_nul_chk_table() {
2796   ImplicitExceptionTable(this).print(code_begin());
2797 }
2798 
2799 void nmethod::print_statistics() {
2800   ttyLocker ttyl;
2801   if (xtty != NULL)  xtty->head("statistics type='nmethod'");
2802   nmethod_stats.print_native_nmethod_stats();
2803   nmethod_stats.print_nmethod_stats();
2804   DebugInformationRecorder::print_statistics();
2805   nmethod_stats.print_pc_stats();
2806   Dependencies::print_statistics();
2807   if (xtty != NULL)  xtty->tail("statistics");
2808 }
2809 
2810 #endif // PRODUCT