1 /*
   2  * Copyright (c) 1997, 2012, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "code/codeCache.hpp"
  27 #include "code/compiledIC.hpp"
  28 #include "code/dependencies.hpp"
  29 #include "code/nmethod.hpp"
  30 #include "code/scopeDesc.hpp"
  31 #include "compiler/abstractCompiler.hpp"
  32 #include "compiler/compileBroker.hpp"
  33 #include "compiler/compileLog.hpp"
  34 #include "compiler/compilerOracle.hpp"
  35 #include "compiler/disassembler.hpp"
  36 #include "interpreter/bytecode.hpp"
  37 #include "oops/methodData.hpp"
  38 #include "prims/jvmtiRedefineClassesTrace.hpp"
  39 #include "prims/jvmtiImpl.hpp"
  40 #include "runtime/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     Method* m = (method);                                                 \
  63     if (m != NULL) {                                                      \
  64       Symbol* klass_name = m->klass_name();                               \
  65       Symbol* name = m->name();                                           \
  66       Symbol* signature = m->signature();                                 \
  67       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     Method* 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   _lazy_critical_native       = 0;
 466   _marked_for_deoptimization  = 0;
 467   _lock_count                 = 0;
 468   _stack_traversal_mark       = 0;
 469   _unload_reported            = false;           // jvmti state
 470 
 471 #ifdef ASSERT
 472   _oops_are_stale             = false;
 473 #endif
 474 
 475   _oops_do_mark_link       = NULL;
 476   _jmethod_id              = NULL;
 477   _osr_link                = NULL;
 478   _scavenge_root_link      = NULL;
 479   _scavenge_root_state     = 0;
 480   _saved_nmethod_link      = NULL;
 481   _compiler                = NULL;
 482 
 483 #ifdef HAVE_DTRACE_H
 484   _trap_offset             = 0;
 485 #endif // def HAVE_DTRACE_H
 486 }
 487 
 488 
 489 nmethod* nmethod::new_native_nmethod(methodHandle method,
 490   int compile_id,
 491   CodeBuffer *code_buffer,
 492   int vep_offset,
 493   int frame_complete,
 494   int frame_size,
 495   ByteSize basic_lock_owner_sp_offset,
 496   ByteSize basic_lock_sp_offset,
 497   OopMapSet* oop_maps) {
 498   code_buffer->finalize_oop_references(method);
 499   // create nmethod
 500   nmethod* nm = NULL;
 501   {
 502     MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
 503     int native_nmethod_size = allocation_size(code_buffer, sizeof(nmethod));
 504     CodeOffsets offsets;
 505     offsets.set_value(CodeOffsets::Verified_Entry, vep_offset);
 506     offsets.set_value(CodeOffsets::Frame_Complete, frame_complete);
 507     nm = new (native_nmethod_size)
 508       nmethod(method(), native_nmethod_size, compile_id, &offsets,
 509               code_buffer, frame_size,
 510               basic_lock_owner_sp_offset, basic_lock_sp_offset,
 511               oop_maps);
 512     NOT_PRODUCT(if (nm != NULL)  nmethod_stats.note_native_nmethod(nm));
 513     if (PrintAssembly && nm != NULL)
 514       Disassembler::decode(nm);
 515   }
 516   // verify nmethod
 517   debug_only(if (nm) nm->verify();) // might block
 518 
 519   if (nm != NULL) {
 520     nm->log_new_nmethod();
 521   }
 522 
 523   return nm;
 524 }
 525 
 526 #ifdef HAVE_DTRACE_H
 527 nmethod* nmethod::new_dtrace_nmethod(methodHandle method,
 528                                      CodeBuffer *code_buffer,
 529                                      int vep_offset,
 530                                      int trap_offset,
 531                                      int frame_complete,
 532                                      int frame_size) {
 533   code_buffer->finalize_oop_references(method);
 534   // create nmethod
 535   nmethod* nm = NULL;
 536   {
 537     MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
 538     int nmethod_size = allocation_size(code_buffer, sizeof(nmethod));
 539     CodeOffsets offsets;
 540     offsets.set_value(CodeOffsets::Verified_Entry, vep_offset);
 541     offsets.set_value(CodeOffsets::Dtrace_trap, trap_offset);
 542     offsets.set_value(CodeOffsets::Frame_Complete, frame_complete);
 543 
 544     nm = new (nmethod_size) nmethod(method(), nmethod_size, &offsets, code_buffer, frame_size);
 545 
 546     NOT_PRODUCT(if (nm != NULL)  nmethod_stats.note_nmethod(nm));
 547     if (PrintAssembly && nm != NULL)
 548       Disassembler::decode(nm);
 549   }
 550   // verify nmethod
 551   debug_only(if (nm) nm->verify();) // might block
 552 
 553   if (nm != NULL) {
 554     nm->log_new_nmethod();
 555   }
 556 
 557   return nm;
 558 }
 559 
 560 #endif // def HAVE_DTRACE_H
 561 
 562 nmethod* nmethod::new_nmethod(methodHandle method,
 563   int compile_id,
 564   int entry_bci,
 565   CodeOffsets* offsets,
 566   int orig_pc_offset,
 567   DebugInformationRecorder* debug_info,
 568   Dependencies* dependencies,
 569   CodeBuffer* code_buffer, int frame_size,
 570   OopMapSet* oop_maps,
 571   ExceptionHandlerTable* handler_table,
 572   ImplicitExceptionTable* nul_chk_table,
 573   AbstractCompiler* compiler,
 574   int comp_level
 575 )
 576 {
 577   assert(debug_info->oop_recorder() == code_buffer->oop_recorder(), "shared OR");
 578   code_buffer->finalize_oop_references(method);
 579   // create nmethod
 580   nmethod* nm = NULL;
 581   { MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
 582     int nmethod_size =
 583       allocation_size(code_buffer, sizeof(nmethod))
 584       + adjust_pcs_size(debug_info->pcs_size())
 585       + round_to(dependencies->size_in_bytes() , oopSize)
 586       + round_to(handler_table->size_in_bytes(), oopSize)
 587       + round_to(nul_chk_table->size_in_bytes(), oopSize)
 588       + round_to(debug_info->data_size()       , oopSize);
 589     nm = new (nmethod_size)
 590       nmethod(method(), nmethod_size, compile_id, entry_bci, offsets,
 591               orig_pc_offset, debug_info, dependencies, code_buffer, frame_size,
 592               oop_maps,
 593               handler_table,
 594               nul_chk_table,
 595               compiler,
 596               comp_level);
 597     if (nm != NULL) {
 598       // To make dependency checking during class loading fast, record
 599       // the nmethod dependencies in the classes it is dependent on.
 600       // This allows the dependency checking code to simply walk the
 601       // class hierarchy above the loaded class, checking only nmethods
 602       // which are dependent on those classes.  The slow way is to
 603       // check every nmethod for dependencies which makes it linear in
 604       // the number of methods compiled.  For applications with a lot
 605       // classes the slow way is too slow.
 606       for (Dependencies::DepStream deps(nm); deps.next(); ) {
 607         Klass* klass = deps.context_type();
 608         if (klass == NULL)  continue;  // ignore things like evol_method
 609 
 610         // record this nmethod as dependent on this klass
 611         InstanceKlass::cast(klass)->add_dependent_nmethod(nm);
 612       }
 613     }
 614     NOT_PRODUCT(if (nm != NULL)  nmethod_stats.note_nmethod(nm));
 615     if (PrintAssembly && nm != NULL)
 616       Disassembler::decode(nm);
 617   }
 618 
 619   // verify nmethod
 620   debug_only(if (nm) nm->verify();) // might block
 621 
 622   if (nm != NULL) {
 623     nm->log_new_nmethod();
 624   }
 625 
 626   // done
 627   return nm;
 628 }
 629 
 630 
 631 // For native wrappers
 632 nmethod::nmethod(
 633   Method* method,
 634   int nmethod_size,
 635   int compile_id,
 636   CodeOffsets* offsets,
 637   CodeBuffer* code_buffer,
 638   int frame_size,
 639   ByteSize basic_lock_owner_sp_offset,
 640   ByteSize basic_lock_sp_offset,
 641   OopMapSet* oop_maps )
 642   : CodeBlob("native nmethod", code_buffer, sizeof(nmethod),
 643              nmethod_size, offsets->value(CodeOffsets::Frame_Complete), frame_size, oop_maps),
 644   _native_receiver_sp_offset(basic_lock_owner_sp_offset),
 645   _native_basic_lock_sp_offset(basic_lock_sp_offset)
 646 {
 647   {
 648     debug_only(No_Safepoint_Verifier nsv;)
 649     assert_locked_or_safepoint(CodeCache_lock);
 650 
 651     init_defaults();
 652     _method                  = method;
 653     _entry_bci               = InvocationEntryBci;
 654     // We have no exception handler or deopt handler make the
 655     // values something that will never match a pc like the nmethod vtable entry
 656     _exception_offset        = 0;
 657     _deoptimize_offset       = 0;
 658     _deoptimize_mh_offset    = 0;
 659     _orig_pc_offset          = 0;
 660 
 661     _consts_offset           = data_offset();
 662     _stub_offset             = data_offset();
 663     _oops_offset             = data_offset();
 664     _metadata_offset         = _oops_offset         + round_to(code_buffer->total_oop_size(), oopSize);
 665     _scopes_data_offset      = _metadata_offset     + round_to(code_buffer->total_metadata_size(), wordSize);
 666     _scopes_pcs_offset       = _scopes_data_offset;
 667     _dependencies_offset     = _scopes_pcs_offset;
 668     _handler_table_offset    = _dependencies_offset;
 669     _nul_chk_table_offset    = _handler_table_offset;
 670     _nmethod_end_offset      = _nul_chk_table_offset;
 671     _compile_id              = compile_id;
 672     _comp_level              = CompLevel_none;
 673     _entry_point             = code_begin()          + offsets->value(CodeOffsets::Entry);
 674     _verified_entry_point    = code_begin()          + offsets->value(CodeOffsets::Verified_Entry);
 675     _osr_entry_point         = NULL;
 676     _exception_cache         = NULL;
 677     _pc_desc_cache.reset_to(NULL);
 678 
 679     code_buffer->copy_values_to(this);
 680     if (ScavengeRootsInCode && detect_scavenge_root_oops()) {
 681       CodeCache::add_scavenge_root_nmethod(this);
 682     }
 683     debug_only(verify_scavenge_root_oops());
 684     CodeCache::commit(this);
 685   }
 686 
 687   if (PrintNativeNMethods || PrintDebugInfo || PrintRelocations || PrintDependencies) {
 688     ttyLocker ttyl;  // keep the following output all in one block
 689     // This output goes directly to the tty, not the compiler log.
 690     // To enable tools to match it up with the compilation activity,
 691     // be sure to tag this tty output with the compile ID.
 692     if (xtty != NULL) {
 693       xtty->begin_head("print_native_nmethod");
 694       xtty->method(_method);
 695       xtty->stamp();
 696       xtty->end_head(" address='" INTPTR_FORMAT "'", (intptr_t) this);
 697     }
 698     // print the header part first
 699     print();
 700     // then print the requested information
 701     if (PrintNativeNMethods) {
 702       print_code();
 703       oop_maps->print();
 704     }
 705     if (PrintRelocations) {
 706       print_relocations();
 707     }
 708     if (xtty != NULL) {
 709       xtty->tail("print_native_nmethod");
 710     }
 711   }
 712 }
 713 
 714 // For dtrace wrappers
 715 #ifdef HAVE_DTRACE_H
 716 nmethod::nmethod(
 717   Method* method,
 718   int nmethod_size,
 719   CodeOffsets* offsets,
 720   CodeBuffer* code_buffer,
 721   int frame_size)
 722   : CodeBlob("dtrace nmethod", code_buffer, sizeof(nmethod),
 723              nmethod_size, offsets->value(CodeOffsets::Frame_Complete), frame_size, NULL),
 724   _native_receiver_sp_offset(in_ByteSize(-1)),
 725   _native_basic_lock_sp_offset(in_ByteSize(-1))
 726 {
 727   {
 728     debug_only(No_Safepoint_Verifier nsv;)
 729     assert_locked_or_safepoint(CodeCache_lock);
 730 
 731     init_defaults();
 732     _method                  = method;
 733     _entry_bci               = InvocationEntryBci;
 734     // We have no exception handler or deopt handler make the
 735     // values something that will never match a pc like the nmethod vtable entry
 736     _exception_offset        = 0;
 737     _deoptimize_offset       = 0;
 738     _deoptimize_mh_offset    = 0;
 739     _unwind_handler_offset   = -1;
 740     _trap_offset             = offsets->value(CodeOffsets::Dtrace_trap);
 741     _orig_pc_offset          = 0;
 742     _consts_offset           = data_offset();
 743     _stub_offset             = data_offset();
 744     _oops_offset             = data_offset();
 745     _metadata_offset         = _oops_offset         + round_to(code_buffer->total_oop_size(), oopSize);
 746     _scopes_data_offset      = _metadata_offset     + round_to(code_buffer->total_metadata_size(), wordSize);
 747     _scopes_pcs_offset       = _scopes_data_offset;
 748     _dependencies_offset     = _scopes_pcs_offset;
 749     _handler_table_offset    = _dependencies_offset;
 750     _nul_chk_table_offset    = _handler_table_offset;
 751     _nmethod_end_offset      = _nul_chk_table_offset;
 752     _compile_id              = 0;  // default
 753     _comp_level              = CompLevel_none;
 754     _entry_point             = code_begin()          + offsets->value(CodeOffsets::Entry);
 755     _verified_entry_point    = code_begin()          + offsets->value(CodeOffsets::Verified_Entry);
 756     _osr_entry_point         = NULL;
 757     _exception_cache         = NULL;
 758     _pc_desc_cache.reset_to(NULL);
 759 
 760     code_buffer->copy_values_to(this);
 761     debug_only(verify_scavenge_root_oops());
 762     CodeCache::commit(this);
 763   }
 764 
 765   if (PrintNMethods || PrintDebugInfo || PrintRelocations || PrintDependencies) {
 766     ttyLocker ttyl;  // keep the following output all in one block
 767     // This output goes directly to the tty, not the compiler log.
 768     // To enable tools to match it up with the compilation activity,
 769     // be sure to tag this tty output with the compile ID.
 770     if (xtty != NULL) {
 771       xtty->begin_head("print_dtrace_nmethod");
 772       xtty->method(_method);
 773       xtty->stamp();
 774       xtty->end_head(" address='" INTPTR_FORMAT "'", (intptr_t) this);
 775     }
 776     // print the header part first
 777     print();
 778     // then print the requested information
 779     if (PrintNMethods) {
 780       print_code();
 781     }
 782     if (PrintRelocations) {
 783       print_relocations();
 784     }
 785     if (xtty != NULL) {
 786       xtty->tail("print_dtrace_nmethod");
 787     }
 788   }
 789 }
 790 #endif // def HAVE_DTRACE_H
 791 
 792 void* nmethod::operator new(size_t size, int nmethod_size) {
 793   // Always leave some room in the CodeCache for I2C/C2I adapters
 794   if (CodeCache::largest_free_block() < CodeCacheMinimumFreeSpace) return NULL;
 795   return CodeCache::allocate(nmethod_size);
 796 }
 797 
 798 
 799 nmethod::nmethod(
 800   Method* method,
 801   int nmethod_size,
 802   int compile_id,
 803   int entry_bci,
 804   CodeOffsets* offsets,
 805   int orig_pc_offset,
 806   DebugInformationRecorder* debug_info,
 807   Dependencies* dependencies,
 808   CodeBuffer *code_buffer,
 809   int frame_size,
 810   OopMapSet* oop_maps,
 811   ExceptionHandlerTable* handler_table,
 812   ImplicitExceptionTable* nul_chk_table,
 813   AbstractCompiler* compiler,
 814   int comp_level
 815   )
 816   : CodeBlob("nmethod", code_buffer, sizeof(nmethod),
 817              nmethod_size, offsets->value(CodeOffsets::Frame_Complete), frame_size, oop_maps),
 818   _native_receiver_sp_offset(in_ByteSize(-1)),
 819   _native_basic_lock_sp_offset(in_ByteSize(-1))
 820 {
 821   assert(debug_info->oop_recorder() == code_buffer->oop_recorder(), "shared OR");
 822   {
 823     debug_only(No_Safepoint_Verifier nsv;)
 824     assert_locked_or_safepoint(CodeCache_lock);
 825 
 826     init_defaults();
 827     _method                  = method;
 828     _entry_bci               = entry_bci;
 829     _compile_id              = compile_id;
 830     _comp_level              = comp_level;
 831     _compiler                = compiler;
 832     _orig_pc_offset          = orig_pc_offset;
 833 
 834     // Section offsets
 835     _consts_offset           = content_offset()      + code_buffer->total_offset_of(code_buffer->consts());
 836     _stub_offset             = content_offset()      + code_buffer->total_offset_of(code_buffer->stubs());
 837 
 838     // Exception handler and deopt handler are in the stub section
 839     assert(offsets->value(CodeOffsets::Exceptions) != -1, "must be set");
 840     assert(offsets->value(CodeOffsets::Deopt     ) != -1, "must be set");
 841     _exception_offset        = _stub_offset          + offsets->value(CodeOffsets::Exceptions);
 842     _deoptimize_offset       = _stub_offset          + offsets->value(CodeOffsets::Deopt);
 843     if (offsets->value(CodeOffsets::DeoptMH) != -1) {
 844       _deoptimize_mh_offset  = _stub_offset          + offsets->value(CodeOffsets::DeoptMH);
 845     } else {
 846       _deoptimize_mh_offset  = -1;
 847     }
 848     if (offsets->value(CodeOffsets::UnwindHandler) != -1) {
 849       _unwind_handler_offset = code_offset()         + offsets->value(CodeOffsets::UnwindHandler);
 850     } else {
 851       _unwind_handler_offset = -1;
 852     }
 853 
 854     _oops_offset             = data_offset();
 855     _metadata_offset         = _oops_offset          + round_to(code_buffer->total_oop_size(), oopSize);
 856     _scopes_data_offset      = _metadata_offset      + round_to(code_buffer->total_metadata_size(), wordSize);
 857 
 858     _scopes_pcs_offset       = _scopes_data_offset   + round_to(debug_info->data_size       (), oopSize);
 859     _dependencies_offset     = _scopes_pcs_offset    + adjust_pcs_size(debug_info->pcs_size());
 860     _handler_table_offset    = _dependencies_offset  + round_to(dependencies->size_in_bytes (), oopSize);
 861     _nul_chk_table_offset    = _handler_table_offset + round_to(handler_table->size_in_bytes(), oopSize);
 862     _nmethod_end_offset      = _nul_chk_table_offset + round_to(nul_chk_table->size_in_bytes(), oopSize);
 863 
 864     _entry_point             = code_begin()          + offsets->value(CodeOffsets::Entry);
 865     _verified_entry_point    = code_begin()          + offsets->value(CodeOffsets::Verified_Entry);
 866     _osr_entry_point         = code_begin()          + offsets->value(CodeOffsets::OSR_Entry);
 867     _exception_cache         = NULL;
 868     _pc_desc_cache.reset_to(scopes_pcs_begin());
 869 
 870     // Copy contents of ScopeDescRecorder to nmethod
 871     code_buffer->copy_values_to(this);
 872     debug_info->copy_to(this);
 873     dependencies->copy_to(this);
 874     if (ScavengeRootsInCode && detect_scavenge_root_oops()) {
 875       CodeCache::add_scavenge_root_nmethod(this);
 876     }
 877     debug_only(verify_scavenge_root_oops());
 878 
 879     CodeCache::commit(this);
 880 
 881     // Copy contents of ExceptionHandlerTable to nmethod
 882     handler_table->copy_to(this);
 883     nul_chk_table->copy_to(this);
 884 
 885     // we use the information of entry points to find out if a method is
 886     // static or non static
 887     assert(compiler->is_c2() ||
 888            _method->is_static() == (entry_point() == _verified_entry_point),
 889            " entry points must be same for static methods and vice versa");
 890   }
 891 
 892   bool printnmethods = PrintNMethods
 893     || CompilerOracle::should_print(_method)
 894     || CompilerOracle::has_option_string(_method, "PrintNMethods");
 895   if (printnmethods || PrintDebugInfo || PrintRelocations || PrintDependencies || PrintExceptionHandlers) {
 896     print_nmethod(printnmethods);
 897   }
 898 }
 899 
 900 
 901 // Print a short set of xml attributes to identify this nmethod.  The
 902 // output should be embedded in some other element.
 903 void nmethod::log_identity(xmlStream* log) const {
 904   log->print(" compile_id='%d'", compile_id());
 905   const char* nm_kind = compile_kind();
 906   if (nm_kind != NULL)  log->print(" compile_kind='%s'", nm_kind);
 907   if (compiler() != NULL) {
 908     log->print(" compiler='%s'", compiler()->name());
 909   }
 910   if (TieredCompilation) {
 911     log->print(" level='%d'", comp_level());
 912   }
 913 }
 914 
 915 
 916 #define LOG_OFFSET(log, name)                    \
 917   if ((intptr_t)name##_end() - (intptr_t)name##_begin()) \
 918     log->print(" " XSTR(name) "_offset='%d'"    , \
 919                (intptr_t)name##_begin() - (intptr_t)this)
 920 
 921 
 922 void nmethod::log_new_nmethod() const {
 923   if (LogCompilation && xtty != NULL) {
 924     ttyLocker ttyl;
 925     HandleMark hm;
 926     xtty->begin_elem("nmethod");
 927     log_identity(xtty);
 928     xtty->print(" entry='" INTPTR_FORMAT "' size='%d'", code_begin(), size());
 929     xtty->print(" address='" INTPTR_FORMAT "'", (intptr_t) this);
 930 
 931     LOG_OFFSET(xtty, relocation);
 932     LOG_OFFSET(xtty, consts);
 933     LOG_OFFSET(xtty, insts);
 934     LOG_OFFSET(xtty, stub);
 935     LOG_OFFSET(xtty, scopes_data);
 936     LOG_OFFSET(xtty, scopes_pcs);
 937     LOG_OFFSET(xtty, dependencies);
 938     LOG_OFFSET(xtty, handler_table);
 939     LOG_OFFSET(xtty, nul_chk_table);
 940     LOG_OFFSET(xtty, oops);
 941 
 942     xtty->method(method());
 943     xtty->stamp();
 944     xtty->end_elem();
 945   }
 946 }
 947 
 948 #undef LOG_OFFSET
 949 
 950 
 951 // Print out more verbose output usually for a newly created nmethod.
 952 void nmethod::print_on(outputStream* st, const char* msg) const {
 953   if (st != NULL) {
 954     ttyLocker ttyl;
 955     if (WizardMode) {
 956       CompileTask::print_compilation(st, this, msg, /*short_form:*/ true);
 957       st->print_cr(" (" INTPTR_FORMAT ")", this);
 958     } else {
 959       CompileTask::print_compilation(st, this, msg, /*short_form:*/ false);
 960     }
 961   }
 962 }
 963 
 964 
 965 void nmethod::print_nmethod(bool printmethod) {
 966   ttyLocker ttyl;  // keep the following output all in one block
 967   if (xtty != NULL) {
 968     xtty->begin_head("print_nmethod");
 969     xtty->stamp();
 970     xtty->end_head();
 971   }
 972   // print the header part first
 973   print();
 974   // then print the requested information
 975   if (printmethod) {
 976     print_code();
 977     print_pcs();
 978     if (oop_maps()) {
 979       oop_maps()->print();
 980     }
 981   }
 982   if (PrintDebugInfo) {
 983     print_scopes();
 984   }
 985   if (PrintRelocations) {
 986     print_relocations();
 987   }
 988   if (PrintDependencies) {
 989     print_dependencies();
 990   }
 991   if (PrintExceptionHandlers) {
 992     print_handler_table();
 993     print_nul_chk_table();
 994   }
 995   if (xtty != NULL) {
 996     xtty->tail("print_nmethod");
 997   }
 998 }
 999 
1000 
1001 // Promote one word from an assembly-time handle to a live embedded oop.
1002 inline void nmethod::initialize_immediate_oop(oop* dest, jobject handle) {
1003   if (handle == NULL ||
1004       // As a special case, IC oops are initialized to 1 or -1.
1005       handle == (jobject) Universe::non_oop_word()) {
1006     (*dest) = (oop) handle;
1007   } else {
1008     (*dest) = JNIHandles::resolve_non_null(handle);
1009   }
1010 }
1011 
1012 
1013 // Have to have the same name because it's called by a template
1014 void nmethod::copy_values(GrowableArray<jobject>* array) {
1015   int length = array->length();
1016   assert((address)(oops_begin() + length) <= (address)oops_end(), "oops big enough");
1017   oop* dest = oops_begin();
1018   for (int index = 0 ; index < length; index++) {
1019     initialize_immediate_oop(&dest[index], array->at(index));
1020   }
1021 
1022   // Now we can fix up all the oops in the code.  We need to do this
1023   // in the code because the assembler uses jobjects as placeholders.
1024   // The code and relocations have already been initialized by the
1025   // CodeBlob constructor, so it is valid even at this early point to
1026   // iterate over relocations and patch the code.
1027   fix_oop_relocations(NULL, NULL, /*initialize_immediates=*/ true);
1028 }
1029 
1030 void nmethod::copy_values(GrowableArray<Metadata*>* array) {
1031   int length = array->length();
1032   assert((address)(metadata_begin() + length) <= (address)metadata_end(), "big enough");
1033   Metadata** dest = metadata_begin();
1034   for (int index = 0 ; index < length; index++) {
1035     dest[index] = array->at(index);
1036   }
1037 }
1038 
1039 bool nmethod::is_at_poll_return(address pc) {
1040   RelocIterator iter(this, pc, pc+1);
1041   while (iter.next()) {
1042     if (iter.type() == relocInfo::poll_return_type)
1043       return true;
1044   }
1045   return false;
1046 }
1047 
1048 
1049 bool nmethod::is_at_poll_or_poll_return(address pc) {
1050   RelocIterator iter(this, pc, pc+1);
1051   while (iter.next()) {
1052     relocInfo::relocType t = iter.type();
1053     if (t == relocInfo::poll_return_type || t == relocInfo::poll_type)
1054       return true;
1055   }
1056   return false;
1057 }
1058 
1059 
1060 void nmethod::fix_oop_relocations(address begin, address end, bool initialize_immediates) {
1061   // re-patch all oop-bearing instructions, just in case some oops moved
1062   RelocIterator iter(this, begin, end);
1063   while (iter.next()) {
1064     if (iter.type() == relocInfo::oop_type) {
1065       oop_Relocation* reloc = iter.oop_reloc();
1066       if (initialize_immediates && reloc->oop_is_immediate()) {
1067         oop* dest = reloc->oop_addr();
1068         initialize_immediate_oop(dest, (jobject) *dest);
1069       }
1070       // Refresh the oop-related bits of this instruction.
1071       reloc->fix_oop_relocation();
1072     } else if (iter.type() == relocInfo::metadata_type) {
1073       metadata_Relocation* reloc = iter.metadata_reloc();
1074       reloc->fix_metadata_relocation();
1075     }
1076 
1077     // There must not be any interfering patches or breakpoints.
1078     assert(!(iter.type() == relocInfo::breakpoint_type
1079              && iter.breakpoint_reloc()->active()),
1080            "no active breakpoint");
1081   }
1082 }
1083 
1084 
1085 void nmethod::verify_oop_relocations() {
1086   // Ensure sure that the code matches the current oop values
1087   RelocIterator iter(this, NULL, NULL);
1088   while (iter.next()) {
1089     if (iter.type() == relocInfo::oop_type) {
1090       oop_Relocation* reloc = iter.oop_reloc();
1091       if (!reloc->oop_is_immediate()) {
1092         reloc->verify_oop_relocation();
1093       }
1094     }
1095   }
1096 }
1097 
1098 
1099 ScopeDesc* nmethod::scope_desc_at(address pc) {
1100   PcDesc* pd = pc_desc_at(pc);
1101   guarantee(pd != NULL, "scope must be present");
1102   return new ScopeDesc(this, pd->scope_decode_offset(),
1103                        pd->obj_decode_offset(), pd->should_reexecute(),
1104                        pd->return_oop());
1105 }
1106 
1107 
1108 void nmethod::clear_inline_caches() {
1109   assert(SafepointSynchronize::is_at_safepoint(), "cleaning of IC's only allowed at safepoint");
1110   if (is_zombie()) {
1111     return;
1112   }
1113 
1114   RelocIterator iter(this);
1115   while (iter.next()) {
1116     iter.reloc()->clear_inline_cache();
1117   }
1118 }
1119 
1120 
1121 void nmethod::cleanup_inline_caches() {
1122 
1123   assert_locked_or_safepoint(CompiledIC_lock);
1124 
1125   // If the method is not entrant or zombie then a JMP is plastered over the
1126   // first few bytes.  If an oop in the old code was there, that oop
1127   // should not get GC'd.  Skip the first few bytes of oops on
1128   // not-entrant methods.
1129   address low_boundary = verified_entry_point();
1130   if (!is_in_use()) {
1131     low_boundary += NativeJump::instruction_size;
1132     // %%% Note:  On SPARC we patch only a 4-byte trap, not a full NativeJump.
1133     // This means that the low_boundary is going to be a little too high.
1134     // This shouldn't matter, since oops of non-entrant methods are never used.
1135     // In fact, why are we bothering to look at oops in a non-entrant method??
1136   }
1137 
1138   // Find all calls in an nmethod, and clear the ones that points to zombie methods
1139   ResourceMark rm;
1140   RelocIterator iter(this, low_boundary);
1141   while(iter.next()) {
1142     switch(iter.type()) {
1143       case relocInfo::virtual_call_type:
1144       case relocInfo::opt_virtual_call_type: {
1145         CompiledIC *ic = CompiledIC_at(iter.reloc());
1146         // Ok, to lookup references to zombies here
1147         CodeBlob *cb = CodeCache::find_blob_unsafe(ic->ic_destination());
1148         if( cb != NULL && cb->is_nmethod() ) {
1149           nmethod* nm = (nmethod*)cb;
1150           // Clean inline caches pointing to both zombie and not_entrant methods
1151           if (!nm->is_in_use() || (nm->method()->code() != nm)) ic->set_to_clean();
1152         }
1153         break;
1154       }
1155       case relocInfo::static_call_type: {
1156         CompiledStaticCall *csc = compiledStaticCall_at(iter.reloc());
1157         CodeBlob *cb = CodeCache::find_blob_unsafe(csc->destination());
1158         if( cb != NULL && cb->is_nmethod() ) {
1159           nmethod* nm = (nmethod*)cb;
1160           // Clean inline caches pointing to both zombie and not_entrant methods
1161           if (!nm->is_in_use() || (nm->method()->code() != nm)) csc->set_to_clean();
1162         }
1163         break;
1164       }
1165     }
1166   }
1167 }
1168 
1169 // This is a private interface with the sweeper.
1170 void nmethod::mark_as_seen_on_stack() {
1171   assert(is_not_entrant(), "must be a non-entrant method");
1172   // Set the traversal mark to ensure that the sweeper does 2
1173   // cleaning passes before moving to zombie.
1174   set_stack_traversal_mark(NMethodSweeper::traversal_count());
1175 }
1176 
1177 // Tell if a non-entrant method can be converted to a zombie (i.e.,
1178 // there are no activations on the stack, not in use by the VM,
1179 // and not in use by the ServiceThread)
1180 bool nmethod::can_not_entrant_be_converted() {
1181   assert(is_not_entrant(), "must be a non-entrant method");
1182 
1183   // Since the nmethod sweeper only does partial sweep the sweeper's traversal
1184   // count can be greater than the stack traversal count before it hits the
1185   // nmethod for the second time.
1186   return stack_traversal_mark()+1 < NMethodSweeper::traversal_count() &&
1187          !is_locked_by_vm();
1188 }
1189 
1190 void nmethod::inc_decompile_count() {
1191   if (!is_compiled_by_c2()) return;
1192   // Could be gated by ProfileTraps, but do not bother...
1193   Method* m = method();
1194   if (m == NULL)  return;
1195   MethodData* mdo = m->method_data();
1196   if (mdo == NULL)  return;
1197   // There is a benign race here.  See comments in methodData.hpp.
1198   mdo->inc_decompile_count();
1199 }
1200 
1201 void nmethod::make_unloaded(BoolObjectClosure* is_alive, oop cause) {
1202 
1203   post_compiled_method_unload();
1204 
1205   // Since this nmethod is being unloaded, make sure that dependencies
1206   // recorded in instanceKlasses get flushed and pass non-NULL closure to
1207   // indicate that this work is being done during a GC.
1208   assert(Universe::heap()->is_gc_active(), "should only be called during gc");
1209   assert(is_alive != NULL, "Should be non-NULL");
1210   // A non-NULL is_alive closure indicates that this is being called during GC.
1211   flush_dependencies(is_alive);
1212 
1213   // Break cycle between nmethod & method
1214   if (TraceClassUnloading && WizardMode) {
1215     tty->print_cr("[Class unloading: Making nmethod " INTPTR_FORMAT
1216                   " unloadable], Method*(" INTPTR_FORMAT
1217                   "), cause(" INTPTR_FORMAT ")",
1218                   this, (address)_method, (address)cause);
1219     if (!Universe::heap()->is_gc_active())
1220       cause->klass()->print();
1221   }
1222   // Unlink the osr method, so we do not look this up again
1223   if (is_osr_method()) {
1224     invalidate_osr_method();
1225   }
1226   // If _method is already NULL the Method* is about to be unloaded,
1227   // so we don't have to break the cycle. Note that it is possible to
1228   // have the Method* live here, in case we unload the nmethod because
1229   // it is pointing to some oop (other than the Method*) being unloaded.
1230   if (_method != NULL) {
1231     // OSR methods point to the Method*, but the Method* does not
1232     // point back!
1233     if (_method->code() == this) {
1234       _method->clear_code(); // Break a cycle
1235     }
1236     _method = NULL;            // Clear the method of this dead nmethod
1237   }
1238   // Make the class unloaded - i.e., change state and notify sweeper
1239   assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
1240   if (is_in_use()) {
1241     // Transitioning directly from live to unloaded -- so
1242     // we need to force a cache clean-up; remember this
1243     // for later on.
1244     CodeCache::set_needs_cache_clean(true);
1245   }
1246   _state = unloaded;
1247 
1248   // Log the unloading.
1249   log_state_change();
1250 
1251   // The Method* is gone at this point
1252   assert(_method == NULL, "Tautology");
1253 
1254   set_osr_link(NULL);
1255   //set_scavenge_root_link(NULL); // done by prune_scavenge_root_nmethods
1256   NMethodSweeper::notify(this);
1257 }
1258 
1259 void nmethod::invalidate_osr_method() {
1260   assert(_entry_bci != InvocationEntryBci, "wrong kind of nmethod");
1261   // Remove from list of active nmethods
1262   if (method() != NULL)
1263     InstanceKlass::cast(method()->method_holder())->remove_osr_nmethod(this);
1264   // Set entry as invalid
1265   _entry_bci = InvalidOSREntryBci;
1266 }
1267 
1268 void nmethod::log_state_change() const {
1269   if (LogCompilation) {
1270     if (xtty != NULL) {
1271       ttyLocker ttyl;  // keep the following output all in one block
1272       if (_state == unloaded) {
1273         xtty->begin_elem("make_unloaded thread='" UINTX_FORMAT "'",
1274                          os::current_thread_id());
1275       } else {
1276         xtty->begin_elem("make_not_entrant thread='" UINTX_FORMAT "'%s",
1277                          os::current_thread_id(),
1278                          (_state == zombie ? " zombie='1'" : ""));
1279       }
1280       log_identity(xtty);
1281       xtty->stamp();
1282       xtty->end_elem();
1283     }
1284   }
1285   if (PrintCompilation && _state != unloaded) {
1286     print_on(tty, _state == zombie ? "made zombie" : "made not entrant");
1287   }
1288 }
1289 
1290 // Common functionality for both make_not_entrant and make_zombie
1291 bool nmethod::make_not_entrant_or_zombie(unsigned int state) {
1292   assert(state == zombie || state == not_entrant, "must be zombie or not_entrant");
1293   assert(!is_zombie(), "should not already be a zombie");
1294 
1295   // Make sure neither the nmethod nor the method is flushed in case of a safepoint in code below.
1296   nmethodLocker nml(this);
1297   methodHandle the_method(method());
1298   No_Safepoint_Verifier nsv;
1299 
1300   {
1301     // invalidate osr nmethod before acquiring the patching lock since
1302     // they both acquire leaf locks and we don't want a deadlock.
1303     // This logic is equivalent to the logic below for patching the
1304     // verified entry point of regular methods.
1305     if (is_osr_method()) {
1306       // this effectively makes the osr nmethod not entrant
1307       invalidate_osr_method();
1308     }
1309 
1310     // Enter critical section.  Does not block for safepoint.
1311     MutexLockerEx pl(Patching_lock, Mutex::_no_safepoint_check_flag);
1312 
1313     if (_state == state) {
1314       // another thread already performed this transition so nothing
1315       // to do, but return false to indicate this.
1316       return false;
1317     }
1318 
1319     // The caller can be calling the method statically or through an inline
1320     // cache call.
1321     if (!is_osr_method() && !is_not_entrant()) {
1322       NativeJump::patch_verified_entry(entry_point(), verified_entry_point(),
1323                   SharedRuntime::get_handle_wrong_method_stub());
1324     }
1325 
1326     if (is_in_use()) {
1327       // It's a true state change, so mark the method as decompiled.
1328       // Do it only for transition from alive.
1329       inc_decompile_count();
1330     }
1331 
1332     // Change state
1333     _state = state;
1334 
1335     // Log the transition once
1336     log_state_change();
1337 
1338     // Remove nmethod from method.
1339     // We need to check if both the _code and _from_compiled_code_entry_point
1340     // refer to this nmethod because there is a race in setting these two fields
1341     // in Method* as seen in bugid 4947125.
1342     // If the vep() points to the zombie nmethod, the memory for the nmethod
1343     // could be flushed and the compiler and vtable stubs could still call
1344     // through it.
1345     if (method() != NULL && (method()->code() == this ||
1346                              method()->from_compiled_entry() == verified_entry_point())) {
1347       HandleMark hm;
1348       method()->clear_code();
1349     }
1350 
1351     if (state == not_entrant) {
1352       mark_as_seen_on_stack();
1353     }
1354 
1355   } // leave critical region under Patching_lock
1356 
1357   // When the nmethod becomes zombie it is no longer alive so the
1358   // dependencies must be flushed.  nmethods in the not_entrant
1359   // state will be flushed later when the transition to zombie
1360   // happens or they get unloaded.
1361   if (state == zombie) {
1362     {
1363       // Flushing dependecies must be done before any possible
1364       // safepoint can sneak in, otherwise the oops used by the
1365       // dependency logic could have become stale.
1366       MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
1367       flush_dependencies(NULL);
1368     }
1369 
1370     // zombie only - if a JVMTI agent has enabled the CompiledMethodUnload
1371     // event and it hasn't already been reported for this nmethod then
1372     // report it now. The event may have been reported earilier if the GC
1373     // marked it for unloading). JvmtiDeferredEventQueue support means
1374     // we no longer go to a safepoint here.
1375     post_compiled_method_unload();
1376 
1377 #ifdef ASSERT
1378     // It's no longer safe to access the oops section since zombie
1379     // nmethods aren't scanned for GC.
1380     _oops_are_stale = true;
1381 #endif
1382   } else {
1383     assert(state == not_entrant, "other cases may need to be handled differently");
1384   }
1385 
1386   if (TraceCreateZombies) {
1387     tty->print_cr("nmethod <" INTPTR_FORMAT "> code made %s", this, (state == not_entrant) ? "not entrant" : "zombie");
1388   }
1389 
1390   // Make sweeper aware that there is a zombie method that needs to be removed
1391   NMethodSweeper::notify(this);
1392 
1393   return true;
1394 }
1395 
1396 void nmethod::flush() {
1397   // Note that there are no valid oops in the nmethod anymore.
1398   assert(is_zombie() || (is_osr_method() && is_unloaded()), "must be a zombie method");
1399   assert(is_marked_for_reclamation() || (is_osr_method() && is_unloaded()), "must be marked for reclamation");
1400 
1401   assert (!is_locked_by_vm(), "locked methods shouldn't be flushed");
1402   assert_locked_or_safepoint(CodeCache_lock);
1403 
1404   // completely deallocate this method
1405   Events::log(JavaThread::current(), "flushing nmethod " INTPTR_FORMAT, this);
1406   if (PrintMethodFlushing) {
1407     tty->print_cr("*flushing nmethod %3d/" INTPTR_FORMAT ". Live blobs:" UINT32_FORMAT "/Free CodeCache:" SIZE_FORMAT "Kb",
1408         _compile_id, this, CodeCache::nof_blobs(), CodeCache::unallocated_capacity()/1024);
1409   }
1410 
1411   // We need to deallocate any ExceptionCache data.
1412   // Note that we do not need to grab the nmethod lock for this, it
1413   // better be thread safe if we're disposing of it!
1414   ExceptionCache* ec = exception_cache();
1415   set_exception_cache(NULL);
1416   while(ec != NULL) {
1417     ExceptionCache* next = ec->next();
1418     delete ec;
1419     ec = next;
1420   }
1421 
1422   if (on_scavenge_root_list()) {
1423     CodeCache::drop_scavenge_root_nmethod(this);
1424   }
1425 
1426   if (is_speculatively_disconnected()) {
1427     CodeCache::remove_saved_code(this);
1428   }
1429 
1430 #ifdef SHARK
1431   ((SharkCompiler *) compiler())->free_compiled_method(insts_begin());
1432 #endif // SHARK
1433 
1434   ((CodeBlob*)(this))->flush();
1435 
1436   CodeCache::free(this);
1437 }
1438 
1439 
1440 //
1441 // Notify all classes this nmethod is dependent on that it is no
1442 // longer dependent. This should only be called in two situations.
1443 // First, when a nmethod transitions to a zombie all dependents need
1444 // to be clear.  Since zombification happens at a safepoint there's no
1445 // synchronization issues.  The second place is a little more tricky.
1446 // During phase 1 of mark sweep class unloading may happen and as a
1447 // result some nmethods may get unloaded.  In this case the flushing
1448 // of dependencies must happen during phase 1 since after GC any
1449 // dependencies in the unloaded nmethod won't be updated, so
1450 // traversing the dependency information in unsafe.  In that case this
1451 // function is called with a non-NULL argument and this function only
1452 // notifies instanceKlasses that are reachable
1453 
1454 void nmethod::flush_dependencies(BoolObjectClosure* is_alive) {
1455   assert_locked_or_safepoint(CodeCache_lock);
1456   assert(Universe::heap()->is_gc_active() == (is_alive != NULL),
1457   "is_alive is non-NULL if and only if we are called during GC");
1458   if (!has_flushed_dependencies()) {
1459     set_has_flushed_dependencies();
1460     for (Dependencies::DepStream deps(this); deps.next(); ) {
1461       Klass* klass = deps.context_type();
1462       if (klass == NULL)  continue;  // ignore things like evol_method
1463 
1464       // During GC the is_alive closure is non-NULL, and is used to
1465       // determine liveness of dependees that need to be updated.
1466       if (is_alive == NULL || klass->is_loader_alive(is_alive)) {
1467         InstanceKlass::cast(klass)->remove_dependent_nmethod(this);
1468       }
1469     }
1470   }
1471 }
1472 
1473 
1474 // If this oop is not live, the nmethod can be unloaded.
1475 bool nmethod::can_unload(BoolObjectClosure* is_alive,
1476                          OopClosure* keep_alive,
1477                          oop* root, bool unloading_occurred) {
1478   assert(root != NULL, "just checking");
1479   oop obj = *root;
1480   if (obj == NULL || is_alive->do_object_b(obj)) {
1481       return false;
1482   }
1483 
1484   // If ScavengeRootsInCode is true, an nmethod might be unloaded
1485   // simply because one of its constant oops has gone dead.
1486   // No actual classes need to be unloaded in order for this to occur.
1487   assert(unloading_occurred || ScavengeRootsInCode, "Inconsistency in unloading");
1488   make_unloaded(is_alive, obj);
1489   return true;
1490 }
1491 
1492 // ------------------------------------------------------------------
1493 // post_compiled_method_load_event
1494 // new method for install_code() path
1495 // Transfer information from compilation to jvmti
1496 void nmethod::post_compiled_method_load_event() {
1497 
1498   Method* moop = method();
1499 #ifndef USDT2
1500   HS_DTRACE_PROBE8(hotspot, compiled__method__load,
1501       moop->klass_name()->bytes(),
1502       moop->klass_name()->utf8_length(),
1503       moop->name()->bytes(),
1504       moop->name()->utf8_length(),
1505       moop->signature()->bytes(),
1506       moop->signature()->utf8_length(),
1507       insts_begin(), insts_size());
1508 #else /* USDT2 */
1509   HOTSPOT_COMPILED_METHOD_LOAD(
1510       (char *) moop->klass_name()->bytes(),
1511       moop->klass_name()->utf8_length(),
1512       (char *) moop->name()->bytes(),
1513       moop->name()->utf8_length(),
1514       (char *) moop->signature()->bytes(),
1515       moop->signature()->utf8_length(),
1516       insts_begin(), insts_size());
1517 #endif /* USDT2 */
1518 
1519   if (JvmtiExport::should_post_compiled_method_load() ||
1520       JvmtiExport::should_post_compiled_method_unload()) {
1521     get_and_cache_jmethod_id();
1522   }
1523 
1524   if (JvmtiExport::should_post_compiled_method_load()) {
1525     // Let the Service thread (which is a real Java thread) post the event
1526     MutexLockerEx ml(Service_lock, Mutex::_no_safepoint_check_flag);
1527     JvmtiDeferredEventQueue::enqueue(
1528       JvmtiDeferredEvent::compiled_method_load_event(this));
1529   }
1530 }
1531 
1532 jmethodID nmethod::get_and_cache_jmethod_id() {
1533   if (_jmethod_id == NULL) {
1534     // Cache the jmethod_id since it can no longer be looked up once the
1535     // method itself has been marked for unloading.
1536     _jmethod_id = method()->jmethod_id();
1537   }
1538   return _jmethod_id;
1539 }
1540 
1541 void nmethod::post_compiled_method_unload() {
1542   if (unload_reported()) {
1543     // During unloading we transition to unloaded and then to zombie
1544     // and the unloading is reported during the first transition.
1545     return;
1546   }
1547 
1548   assert(_method != NULL && !is_unloaded(), "just checking");
1549   DTRACE_METHOD_UNLOAD_PROBE(method());
1550 
1551   // If a JVMTI agent has enabled the CompiledMethodUnload event then
1552   // post the event. Sometime later this nmethod will be made a zombie
1553   // by the sweeper but the Method* will not be valid at that point.
1554   // If the _jmethod_id is null then no load event was ever requested
1555   // so don't bother posting the unload.  The main reason for this is
1556   // that the jmethodID is a weak reference to the Method* so if
1557   // it's being unloaded there's no way to look it up since the weak
1558   // ref will have been cleared.
1559   if (_jmethod_id != NULL && JvmtiExport::should_post_compiled_method_unload()) {
1560     assert(!unload_reported(), "already unloaded");
1561     JvmtiDeferredEvent event =
1562       JvmtiDeferredEvent::compiled_method_unload_event(this,
1563           _jmethod_id, insts_begin());
1564     if (SafepointSynchronize::is_at_safepoint()) {
1565       // Don't want to take the queueing lock. Add it as pending and
1566       // it will get enqueued later.
1567       JvmtiDeferredEventQueue::add_pending_event(event);
1568     } else {
1569       MutexLockerEx ml(Service_lock, Mutex::_no_safepoint_check_flag);
1570       JvmtiDeferredEventQueue::enqueue(event);
1571     }
1572   }
1573 
1574   // The JVMTI CompiledMethodUnload event can be enabled or disabled at
1575   // any time. As the nmethod is being unloaded now we mark it has
1576   // having the unload event reported - this will ensure that we don't
1577   // attempt to report the event in the unlikely scenario where the
1578   // event is enabled at the time the nmethod is made a zombie.
1579   set_unload_reported();
1580 }
1581 
1582 // This is called at the end of the strong tracing/marking phase of a
1583 // GC to unload an nmethod if it contains otherwise unreachable
1584 // oops.
1585 
1586 void nmethod::do_unloading(BoolObjectClosure* is_alive,
1587                            OopClosure* keep_alive, bool unloading_occurred) {
1588   // Make sure the oop's ready to receive visitors
1589   assert(!is_zombie() && !is_unloaded(),
1590          "should not call follow on zombie or unloaded nmethod");
1591 
1592   // If the method is not entrant then a JMP is plastered over the
1593   // first few bytes.  If an oop in the old code was there, that oop
1594   // should not get GC'd.  Skip the first few bytes of oops on
1595   // not-entrant methods.
1596   address low_boundary = verified_entry_point();
1597   if (is_not_entrant()) {
1598     low_boundary += NativeJump::instruction_size;
1599     // %%% Note:  On SPARC we patch only a 4-byte trap, not a full NativeJump.
1600     // (See comment above.)
1601   }
1602 
1603   // The RedefineClasses() API can cause the class unloading invariant
1604   // to no longer be true. See jvmtiExport.hpp for details.
1605   // Also, leave a debugging breadcrumb in local flag.
1606   bool a_class_was_redefined = JvmtiExport::has_redefined_a_class();
1607   if (a_class_was_redefined) {
1608     // This set of the unloading_occurred flag is done before the
1609     // call to post_compiled_method_unload() so that the unloading
1610     // of this nmethod is reported.
1611     unloading_occurred = true;
1612   }
1613 
1614   // Exception cache
1615   ExceptionCache* ec = exception_cache();
1616   while (ec != NULL) {
1617     Klass* ex_klass = ec->exception_type();
1618     ExceptionCache* next_ec = ec->next();
1619     if (ex_klass != NULL && !ex_klass->is_loader_alive(is_alive)) {
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         if (ic->is_icholder_call()) {
1635           // The only exception is compiledICHolder oops which may
1636           // yet be marked below. (We check this further below).
1637           CompiledICHolder* cichk_oop = ic->cached_icholder();
1638           if (cichk_oop->holder_method()->method_holder()->is_loader_alive(is_alive) &&
1639               cichk_oop->holder_klass()->is_loader_alive(is_alive)) {
1640               continue;
1641             }
1642         } else {
1643           Metadata* ic_oop = ic->cached_metadata();
1644           if (ic_oop != NULL) {
1645             if (ic_oop->is_klass()) {
1646               if (((Klass*)ic_oop)->is_loader_alive(is_alive)) {
1647                 continue;
1648               }
1649             } else if (ic_oop->is_method()) {
1650               if (((Method*)ic_oop)->method_holder()->is_loader_alive(is_alive)) {
1651                 continue;
1652               }
1653             } else {
1654               ShouldNotReachHere();
1655             }
1656           }
1657           }
1658           ic->set_to_clean();
1659       }
1660     }
1661   }
1662 
1663   // Compiled code
1664   {
1665   RelocIterator iter(this, low_boundary);
1666   while (iter.next()) {
1667     if (iter.type() == relocInfo::oop_type) {
1668       oop_Relocation* r = iter.oop_reloc();
1669       // In this loop, we must only traverse those oops directly embedded in
1670       // the code.  Other oops (oop_index>0) are seen as part of scopes_oops.
1671       assert(1 == (r->oop_is_immediate()) +
1672                   (r->oop_addr() >= oops_begin() && r->oop_addr() < oops_end()),
1673              "oop must be found in exactly one place");
1674       if (r->oop_is_immediate() && r->oop_value() != NULL) {
1675         if (can_unload(is_alive, keep_alive, r->oop_addr(), unloading_occurred)) {
1676           return;
1677         }
1678       }
1679     }
1680   }
1681   }
1682 
1683 
1684   // Scopes
1685   for (oop* p = oops_begin(); p < oops_end(); p++) {
1686     if (*p == Universe::non_oop_word())  continue;  // skip non-oops
1687     if (can_unload(is_alive, keep_alive, p, unloading_occurred)) {
1688       return;
1689     }
1690   }
1691 
1692   // Ensure that all metadata is still alive
1693   verify_metadata_loaders(low_boundary, is_alive);
1694 }
1695 
1696 #ifdef ASSERT
1697 
1698 class CheckClass : AllStatic {
1699   static BoolObjectClosure* _is_alive;
1700 
1701   // Check class_loader is alive for this bit of metadata.
1702   static void check_class(Metadata* md) {
1703     Klass* klass = NULL;
1704     if (md->is_klass()) {
1705       klass = ((Klass*)md);
1706     } else if (md->is_method()) {
1707       klass = ((Method*)md)->method_holder();
1708     } else if (md->is_methodData()) {
1709       klass = ((MethodData*)md)->method()->method_holder();
1710     } else {
1711       md->print();
1712       ShouldNotReachHere();
1713     }
1714     assert(klass->is_loader_alive(_is_alive), "must be alive");
1715   }
1716  public:
1717   static void do_check_class(BoolObjectClosure* is_alive, nmethod* nm) {
1718     assert(SafepointSynchronize::is_at_safepoint(), "this is only ok at safepoint");
1719     _is_alive = is_alive;
1720     nm->metadata_do(check_class);
1721   }
1722 };
1723 
1724 // This is called during a safepoint so can use static data
1725 BoolObjectClosure* CheckClass::_is_alive = NULL;
1726 #endif // ASSERT
1727 
1728 
1729 // Processing of oop references should have been sufficient to keep
1730 // all strong references alive.  Any weak references should have been
1731 // cleared as well.  Visit all the metadata and ensure that it's
1732 // really alive.
1733 void nmethod::verify_metadata_loaders(address low_boundary, BoolObjectClosure* is_alive) {
1734 #ifdef ASSERT
1735     RelocIterator iter(this, low_boundary);
1736     while (iter.next()) {
1737     // static_stub_Relocations may have dangling references to
1738     // Method*s so trim them out here.  Otherwise it looks like
1739     // compiled code is maintaining a link to dead metadata.
1740     address static_call_addr = NULL;
1741     if (iter.type() == relocInfo::opt_virtual_call_type) {
1742       CompiledIC* cic = CompiledIC_at(iter.reloc());
1743       if (!cic->is_call_to_interpreted()) {
1744         static_call_addr = iter.addr();
1745       }
1746     } else if (iter.type() == relocInfo::static_call_type) {
1747       CompiledStaticCall* csc = compiledStaticCall_at(iter.reloc());
1748       if (!csc->is_call_to_interpreted()) {
1749         static_call_addr = iter.addr();
1750       }
1751     }
1752     if (static_call_addr != NULL) {
1753       RelocIterator sciter(this, low_boundary);
1754       while (sciter.next()) {
1755         if (sciter.type() == relocInfo::static_stub_type &&
1756             sciter.static_stub_reloc()->static_call() == static_call_addr) {
1757           sciter.static_stub_reloc()->clear_inline_cache();
1758         }
1759       }
1760     }
1761   }
1762   // Check that the metadata embedded in the nmethod is alive
1763   CheckClass::do_check_class(is_alive, this);
1764 #endif
1765 }
1766 
1767 
1768 // Iterate over metadata calling this function.   Used by RedefineClasses
1769 void nmethod::metadata_do(void f(Metadata*)) {
1770   address low_boundary = verified_entry_point();
1771   if (is_not_entrant()) {
1772     low_boundary += NativeJump::instruction_size;
1773     // %%% Note:  On SPARC we patch only a 4-byte trap, not a full NativeJump.
1774     // (See comment above.)
1775   }
1776   {
1777     // Visit all immediate references that are embedded in the instruction stream.
1778     RelocIterator iter(this, low_boundary);
1779     while (iter.next()) {
1780       if (iter.type() == relocInfo::metadata_type ) {
1781         metadata_Relocation* r = iter.metadata_reloc();
1782         // In this lmetadata, we must only follow those metadatas directly embedded in
1783         // the code.  Other metadatas (oop_index>0) are seen as part of
1784         // the metadata section below.
1785         assert(1 == (r->metadata_is_immediate()) +
1786                (r->metadata_addr() >= metadata_begin() && r->metadata_addr() < metadata_end()),
1787                "metadata must be found in exactly one place");
1788         if (r->metadata_is_immediate() && r->metadata_value() != NULL) {
1789           Metadata* md = r->metadata_value();
1790           f(md);
1791         }
1792       }
1793     }
1794   }
1795 
1796   // Visit the metadata section
1797   for (Metadata** p = metadata_begin(); p < metadata_end(); p++) {
1798     if (*p == Universe::non_oop_word() || *p == NULL)  continue;  // skip non-oops
1799     Metadata* md = *p;
1800     f(md);
1801   }
1802   // Call function Method*, not embedded in these other places.
1803   if (_method != NULL) f(_method);
1804 }
1805 
1806 
1807 // This method is called twice during GC -- once while
1808 // tracing the "active" nmethods on thread stacks during
1809 // the (strong) marking phase, and then again when walking
1810 // the code cache contents during the weak roots processing
1811 // phase. The two uses are distinguished by means of the
1812 // 'do_strong_roots_only' flag, which is true in the first
1813 // case. We want to walk the weak roots in the nmethod
1814 // only in the second case. The weak roots in the nmethod
1815 // are the oops in the ExceptionCache and the InlineCache
1816 // oops.
1817 void nmethod::oops_do(OopClosure* f, bool do_strong_roots_only) {
1818   // make sure the oops ready to receive visitors
1819   assert(!is_zombie() && !is_unloaded(),
1820          "should not call follow on zombie or unloaded nmethod");
1821 
1822   // If the method is not entrant or zombie then a JMP is plastered over the
1823   // first few bytes.  If an oop in the old code was there, that oop
1824   // should not get GC'd.  Skip the first few bytes of oops on
1825   // not-entrant methods.
1826   address low_boundary = verified_entry_point();
1827   if (is_not_entrant()) {
1828     low_boundary += NativeJump::instruction_size;
1829     // %%% Note:  On SPARC we patch only a 4-byte trap, not a full NativeJump.
1830     // (See comment above.)
1831   }
1832 
1833   RelocIterator iter(this, low_boundary);
1834 
1835   while (iter.next()) {
1836     if (iter.type() == relocInfo::oop_type ) {
1837       oop_Relocation* r = iter.oop_reloc();
1838       // In this loop, we must only follow those oops directly embedded in
1839       // the code.  Other oops (oop_index>0) are seen as part of scopes_oops.
1840       assert(1 == (r->oop_is_immediate()) +
1841                    (r->oop_addr() >= oops_begin() && r->oop_addr() < oops_end()),
1842              "oop must be found in exactly one place");
1843       if (r->oop_is_immediate() && r->oop_value() != NULL) {
1844         f->do_oop(r->oop_addr());
1845       }
1846     }
1847   }
1848 
1849   // Scopes
1850   // This includes oop constants not inlined in the code stream.
1851   for (oop* p = oops_begin(); p < oops_end(); p++) {
1852     if (*p == Universe::non_oop_word())  continue;  // skip non-oops
1853     f->do_oop(p);
1854   }
1855 }
1856 
1857 #define NMETHOD_SENTINEL ((nmethod*)badAddress)
1858 
1859 nmethod* volatile nmethod::_oops_do_mark_nmethods;
1860 
1861 // An nmethod is "marked" if its _mark_link is set non-null.
1862 // Even if it is the end of the linked list, it will have a non-null link value,
1863 // as long as it is on the list.
1864 // This code must be MP safe, because it is used from parallel GC passes.
1865 bool nmethod::test_set_oops_do_mark() {
1866   assert(nmethod::oops_do_marking_is_active(), "oops_do_marking_prologue must be called");
1867   nmethod* observed_mark_link = _oops_do_mark_link;
1868   if (observed_mark_link == NULL) {
1869     // Claim this nmethod for this thread to mark.
1870     observed_mark_link = (nmethod*)
1871       Atomic::cmpxchg_ptr(NMETHOD_SENTINEL, &_oops_do_mark_link, NULL);
1872     if (observed_mark_link == NULL) {
1873 
1874       // Atomically append this nmethod (now claimed) to the head of the list:
1875       nmethod* observed_mark_nmethods = _oops_do_mark_nmethods;
1876       for (;;) {
1877         nmethod* required_mark_nmethods = observed_mark_nmethods;
1878         _oops_do_mark_link = required_mark_nmethods;
1879         observed_mark_nmethods = (nmethod*)
1880           Atomic::cmpxchg_ptr(this, &_oops_do_mark_nmethods, required_mark_nmethods);
1881         if (observed_mark_nmethods == required_mark_nmethods)
1882           break;
1883       }
1884       // Mark was clear when we first saw this guy.
1885       NOT_PRODUCT(if (TraceScavenge)  print_on(tty, "oops_do, mark"));
1886       return false;
1887     }
1888   }
1889   // On fall through, another racing thread marked this nmethod before we did.
1890   return true;
1891 }
1892 
1893 void nmethod::oops_do_marking_prologue() {
1894   NOT_PRODUCT(if (TraceScavenge)  tty->print_cr("[oops_do_marking_prologue"));
1895   assert(_oops_do_mark_nmethods == NULL, "must not call oops_do_marking_prologue twice in a row");
1896   // We use cmpxchg_ptr instead of regular assignment here because the user
1897   // may fork a bunch of threads, and we need them all to see the same state.
1898   void* observed = Atomic::cmpxchg_ptr(NMETHOD_SENTINEL, &_oops_do_mark_nmethods, NULL);
1899   guarantee(observed == NULL, "no races in this sequential code");
1900 }
1901 
1902 void nmethod::oops_do_marking_epilogue() {
1903   assert(_oops_do_mark_nmethods != NULL, "must not call oops_do_marking_epilogue twice in a row");
1904   nmethod* cur = _oops_do_mark_nmethods;
1905   while (cur != NMETHOD_SENTINEL) {
1906     assert(cur != NULL, "not NULL-terminated");
1907     nmethod* next = cur->_oops_do_mark_link;
1908     cur->_oops_do_mark_link = NULL;
1909     cur->fix_oop_relocations();
1910     NOT_PRODUCT(if (TraceScavenge)  cur->print_on(tty, "oops_do, unmark"));
1911     cur = next;
1912   }
1913   void* required = _oops_do_mark_nmethods;
1914   void* observed = Atomic::cmpxchg_ptr(NULL, &_oops_do_mark_nmethods, required);
1915   guarantee(observed == required, "no races in this sequential code");
1916   NOT_PRODUCT(if (TraceScavenge)  tty->print_cr("oops_do_marking_epilogue]"));
1917 }
1918 
1919 class DetectScavengeRoot: public OopClosure {
1920   bool     _detected_scavenge_root;
1921 public:
1922   DetectScavengeRoot() : _detected_scavenge_root(false)
1923   { NOT_PRODUCT(_print_nm = NULL); }
1924   bool detected_scavenge_root() { return _detected_scavenge_root; }
1925   virtual void do_oop(oop* p) {
1926     if ((*p) != NULL && (*p)->is_scavengable()) {
1927       NOT_PRODUCT(maybe_print(p));
1928       _detected_scavenge_root = true;
1929     }
1930   }
1931   virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
1932 
1933 #ifndef PRODUCT
1934   nmethod* _print_nm;
1935   void maybe_print(oop* p) {
1936     if (_print_nm == NULL)  return;
1937     if (!_detected_scavenge_root)  _print_nm->print_on(tty, "new scavenge root");
1938     tty->print_cr(""PTR_FORMAT"[offset=%d] detected scavengable oop "PTR_FORMAT" (found at "PTR_FORMAT")",
1939                   _print_nm, (int)((intptr_t)p - (intptr_t)_print_nm),
1940                   (intptr_t)(*p), (intptr_t)p);
1941     (*p)->print();
1942   }
1943 #endif //PRODUCT
1944 };
1945 
1946 bool nmethod::detect_scavenge_root_oops() {
1947   DetectScavengeRoot detect_scavenge_root;
1948   NOT_PRODUCT(if (TraceScavenge)  detect_scavenge_root._print_nm = this);
1949   oops_do(&detect_scavenge_root);
1950   return detect_scavenge_root.detected_scavenge_root();
1951 }
1952 
1953 // Method that knows how to preserve outgoing arguments at call. This method must be
1954 // called with a frame corresponding to a Java invoke
1955 void nmethod::preserve_callee_argument_oops(frame fr, const RegisterMap *reg_map, OopClosure* f) {
1956 #ifndef SHARK
1957   if (!method()->is_native()) {
1958     SimpleScopeDesc ssd(this, fr.pc());
1959     Bytecode_invoke call(ssd.method(), ssd.bci());
1960     // compiled invokedynamic call sites have an implicit receiver at
1961     // resolution time, so make sure it gets GC'ed.
1962     bool has_receiver = !call.is_invokestatic();
1963     Symbol* signature = call.signature();
1964     fr.oops_compiled_arguments_do(signature, has_receiver, reg_map, f);
1965   }
1966 #endif // !SHARK
1967 }
1968 
1969 
1970 oop nmethod::embeddedOop_at(u_char* p) {
1971   RelocIterator iter(this, p, p + 1);
1972   while (iter.next())
1973     if (iter.type() == relocInfo::oop_type) {
1974       return iter.oop_reloc()->oop_value();
1975     }
1976   return NULL;
1977 }
1978 
1979 
1980 inline bool includes(void* p, void* from, void* to) {
1981   return from <= p && p < to;
1982 }
1983 
1984 
1985 void nmethod::copy_scopes_pcs(PcDesc* pcs, int count) {
1986   assert(count >= 2, "must be sentinel values, at least");
1987 
1988 #ifdef ASSERT
1989   // must be sorted and unique; we do a binary search in find_pc_desc()
1990   int prev_offset = pcs[0].pc_offset();
1991   assert(prev_offset == PcDesc::lower_offset_limit,
1992          "must start with a sentinel");
1993   for (int i = 1; i < count; i++) {
1994     int this_offset = pcs[i].pc_offset();
1995     assert(this_offset > prev_offset, "offsets must be sorted");
1996     prev_offset = this_offset;
1997   }
1998   assert(prev_offset == PcDesc::upper_offset_limit,
1999          "must end with a sentinel");
2000 #endif //ASSERT
2001 
2002   // Search for MethodHandle invokes and tag the nmethod.
2003   for (int i = 0; i < count; i++) {
2004     if (pcs[i].is_method_handle_invoke()) {
2005       set_has_method_handle_invokes(true);
2006       break;
2007     }
2008   }
2009   assert(has_method_handle_invokes() == (_deoptimize_mh_offset != -1), "must have deopt mh handler");
2010 
2011   int size = count * sizeof(PcDesc);
2012   assert(scopes_pcs_size() >= size, "oob");
2013   memcpy(scopes_pcs_begin(), pcs, size);
2014 
2015   // Adjust the final sentinel downward.
2016   PcDesc* last_pc = &scopes_pcs_begin()[count-1];
2017   assert(last_pc->pc_offset() == PcDesc::upper_offset_limit, "sanity");
2018   last_pc->set_pc_offset(content_size() + 1);
2019   for (; last_pc + 1 < scopes_pcs_end(); last_pc += 1) {
2020     // Fill any rounding gaps with copies of the last record.
2021     last_pc[1] = last_pc[0];
2022   }
2023   // The following assert could fail if sizeof(PcDesc) is not
2024   // an integral multiple of oopSize (the rounding term).
2025   // If it fails, change the logic to always allocate a multiple
2026   // of sizeof(PcDesc), and fill unused words with copies of *last_pc.
2027   assert(last_pc + 1 == scopes_pcs_end(), "must match exactly");
2028 }
2029 
2030 void nmethod::copy_scopes_data(u_char* buffer, int size) {
2031   assert(scopes_data_size() >= size, "oob");
2032   memcpy(scopes_data_begin(), buffer, size);
2033 }
2034 
2035 
2036 #ifdef ASSERT
2037 static PcDesc* linear_search(nmethod* nm, int pc_offset, bool approximate) {
2038   PcDesc* lower = nm->scopes_pcs_begin();
2039   PcDesc* upper = nm->scopes_pcs_end();
2040   lower += 1; // exclude initial sentinel
2041   PcDesc* res = NULL;
2042   for (PcDesc* p = lower; p < upper; p++) {
2043     NOT_PRODUCT(--nmethod_stats.pc_desc_tests);  // don't count this call to match_desc
2044     if (match_desc(p, pc_offset, approximate)) {
2045       if (res == NULL)
2046         res = p;
2047       else
2048         res = (PcDesc*) badAddress;
2049     }
2050   }
2051   return res;
2052 }
2053 #endif
2054 
2055 
2056 // Finds a PcDesc with real-pc equal to "pc"
2057 PcDesc* nmethod::find_pc_desc_internal(address pc, bool approximate) {
2058   address base_address = code_begin();
2059   if ((pc < base_address) ||
2060       (pc - base_address) >= (ptrdiff_t) PcDesc::upper_offset_limit) {
2061     return NULL;  // PC is wildly out of range
2062   }
2063   int pc_offset = (int) (pc - base_address);
2064 
2065   // Check the PcDesc cache if it contains the desired PcDesc
2066   // (This as an almost 100% hit rate.)
2067   PcDesc* res = _pc_desc_cache.find_pc_desc(pc_offset, approximate);
2068   if (res != NULL) {
2069     assert(res == linear_search(this, pc_offset, approximate), "cache ok");
2070     return res;
2071   }
2072 
2073   // Fallback algorithm: quasi-linear search for the PcDesc
2074   // Find the last pc_offset less than the given offset.
2075   // The successor must be the required match, if there is a match at all.
2076   // (Use a fixed radix to avoid expensive affine pointer arithmetic.)
2077   PcDesc* lower = scopes_pcs_begin();
2078   PcDesc* upper = scopes_pcs_end();
2079   upper -= 1; // exclude final sentinel
2080   if (lower >= upper)  return NULL;  // native method; no PcDescs at all
2081 
2082 #define assert_LU_OK \
2083   /* invariant on lower..upper during the following search: */ \
2084   assert(lower->pc_offset() <  pc_offset, "sanity"); \
2085   assert(upper->pc_offset() >= pc_offset, "sanity")
2086   assert_LU_OK;
2087 
2088   // Use the last successful return as a split point.
2089   PcDesc* mid = _pc_desc_cache.last_pc_desc();
2090   NOT_PRODUCT(++nmethod_stats.pc_desc_searches);
2091   if (mid->pc_offset() < pc_offset) {
2092     lower = mid;
2093   } else {
2094     upper = mid;
2095   }
2096 
2097   // Take giant steps at first (4096, then 256, then 16, then 1)
2098   const int LOG2_RADIX = 4 /*smaller steps in debug mode:*/ debug_only(-1);
2099   const int RADIX = (1 << LOG2_RADIX);
2100   for (int step = (1 << (LOG2_RADIX*3)); step > 1; step >>= LOG2_RADIX) {
2101     while ((mid = lower + step) < upper) {
2102       assert_LU_OK;
2103       NOT_PRODUCT(++nmethod_stats.pc_desc_searches);
2104       if (mid->pc_offset() < pc_offset) {
2105         lower = mid;
2106       } else {
2107         upper = mid;
2108         break;
2109       }
2110     }
2111     assert_LU_OK;
2112   }
2113 
2114   // Sneak up on the value with a linear search of length ~16.
2115   while (true) {
2116     assert_LU_OK;
2117     mid = lower + 1;
2118     NOT_PRODUCT(++nmethod_stats.pc_desc_searches);
2119     if (mid->pc_offset() < pc_offset) {
2120       lower = mid;
2121     } else {
2122       upper = mid;
2123       break;
2124     }
2125   }
2126 #undef assert_LU_OK
2127 
2128   if (match_desc(upper, pc_offset, approximate)) {
2129     assert(upper == linear_search(this, pc_offset, approximate), "search ok");
2130     _pc_desc_cache.add_pc_desc(upper);
2131     return upper;
2132   } else {
2133     assert(NULL == linear_search(this, pc_offset, approximate), "search ok");
2134     return NULL;
2135   }
2136 }
2137 
2138 
2139 bool nmethod::check_all_dependencies() {
2140   bool found_check = false;
2141   // wholesale check of all dependencies
2142   for (Dependencies::DepStream deps(this); deps.next(); ) {
2143     if (deps.check_dependency() != NULL) {
2144       found_check = true;
2145       NOT_DEBUG(break);
2146     }
2147   }
2148   return found_check;  // tell caller if we found anything
2149 }
2150 
2151 bool nmethod::check_dependency_on(DepChange& changes) {
2152   // What has happened:
2153   // 1) a new class dependee has been added
2154   // 2) dependee and all its super classes have been marked
2155   bool found_check = false;  // set true if we are upset
2156   for (Dependencies::DepStream deps(this); deps.next(); ) {
2157     // Evaluate only relevant dependencies.
2158     if (deps.spot_check_dependency_at(changes) != NULL) {
2159       found_check = true;
2160       NOT_DEBUG(break);
2161     }
2162   }
2163   return found_check;
2164 }
2165 
2166 bool nmethod::is_evol_dependent_on(Klass* dependee) {
2167   InstanceKlass *dependee_ik = InstanceKlass::cast(dependee);
2168   Array<Method*>* dependee_methods = dependee_ik->methods();
2169   for (Dependencies::DepStream deps(this); deps.next(); ) {
2170     if (deps.type() == Dependencies::evol_method) {
2171       Method* method = deps.method_argument(0);
2172       for (int j = 0; j < dependee_methods->length(); j++) {
2173         if (dependee_methods->at(j) == method) {
2174           // RC_TRACE macro has an embedded ResourceMark
2175           RC_TRACE(0x01000000,
2176             ("Found evol dependency of nmethod %s.%s(%s) compile_id=%d on method %s.%s(%s)",
2177             _method->method_holder()->external_name(),
2178             _method->name()->as_C_string(),
2179             _method->signature()->as_C_string(), compile_id(),
2180             method->method_holder()->external_name(),
2181             method->name()->as_C_string(),
2182             method->signature()->as_C_string()));
2183           if (TraceDependencies || LogCompilation)
2184             deps.log_dependency(dependee);
2185           return true;
2186         }
2187       }
2188     }
2189   }
2190   return false;
2191 }
2192 
2193 // Called from mark_for_deoptimization, when dependee is invalidated.
2194 bool nmethod::is_dependent_on_method(Method* dependee) {
2195   for (Dependencies::DepStream deps(this); deps.next(); ) {
2196     if (deps.type() != Dependencies::evol_method)
2197       continue;
2198     Method* method = deps.method_argument(0);
2199     if (method == dependee) return true;
2200   }
2201   return false;
2202 }
2203 
2204 
2205 bool nmethod::is_patchable_at(address instr_addr) {
2206   assert(insts_contains(instr_addr), "wrong nmethod used");
2207   if (is_zombie()) {
2208     // a zombie may never be patched
2209     return false;
2210   }
2211   return true;
2212 }
2213 
2214 
2215 address nmethod::continuation_for_implicit_exception(address pc) {
2216   // Exception happened outside inline-cache check code => we are inside
2217   // an active nmethod => use cpc to determine a return address
2218   int exception_offset = pc - code_begin();
2219   int cont_offset = ImplicitExceptionTable(this).at( exception_offset );
2220 #ifdef ASSERT
2221   if (cont_offset == 0) {
2222     Thread* thread = ThreadLocalStorage::get_thread_slow();
2223     ResetNoHandleMark rnm; // Might be called from LEAF/QUICK ENTRY
2224     HandleMark hm(thread);
2225     ResourceMark rm(thread);
2226     CodeBlob* cb = CodeCache::find_blob(pc);
2227     assert(cb != NULL && cb == this, "");
2228     tty->print_cr("implicit exception happened at " INTPTR_FORMAT, pc);
2229     print();
2230     method()->print_codes();
2231     print_code();
2232     print_pcs();
2233   }
2234 #endif
2235   if (cont_offset == 0) {
2236     // Let the normal error handling report the exception
2237     return NULL;
2238   }
2239   return code_begin() + cont_offset;
2240 }
2241 
2242 
2243 
2244 void nmethod_init() {
2245   // make sure you didn't forget to adjust the filler fields
2246   assert(sizeof(nmethod) % oopSize == 0, "nmethod size must be multiple of a word");
2247 }
2248 
2249 
2250 //-------------------------------------------------------------------------------------------
2251 
2252 
2253 // QQQ might we make this work from a frame??
2254 nmethodLocker::nmethodLocker(address pc) {
2255   CodeBlob* cb = CodeCache::find_blob(pc);
2256   guarantee(cb != NULL && cb->is_nmethod(), "bad pc for a nmethod found");
2257   _nm = (nmethod*)cb;
2258   lock_nmethod(_nm);
2259 }
2260 
2261 // Only JvmtiDeferredEvent::compiled_method_unload_event()
2262 // should pass zombie_ok == true.
2263 void nmethodLocker::lock_nmethod(nmethod* nm, bool zombie_ok) {
2264   if (nm == NULL)  return;
2265   Atomic::inc(&nm->_lock_count);
2266   guarantee(zombie_ok || !nm->is_zombie(), "cannot lock a zombie method");
2267 }
2268 
2269 void nmethodLocker::unlock_nmethod(nmethod* nm) {
2270   if (nm == NULL)  return;
2271   Atomic::dec(&nm->_lock_count);
2272   guarantee(nm->_lock_count >= 0, "unmatched nmethod lock/unlock");
2273 }
2274 
2275 
2276 // -----------------------------------------------------------------------------
2277 // nmethod::get_deopt_original_pc
2278 //
2279 // Return the original PC for the given PC if:
2280 // (a) the given PC belongs to a nmethod and
2281 // (b) it is a deopt PC
2282 address nmethod::get_deopt_original_pc(const frame* fr) {
2283   if (fr->cb() == NULL)  return NULL;
2284 
2285   nmethod* nm = fr->cb()->as_nmethod_or_null();
2286   if (nm != NULL && nm->is_deopt_pc(fr->pc()))
2287     return nm->get_original_pc(fr);
2288 
2289   return NULL;
2290 }
2291 
2292 
2293 // -----------------------------------------------------------------------------
2294 // MethodHandle
2295 
2296 bool nmethod::is_method_handle_return(address return_pc) {
2297   if (!has_method_handle_invokes())  return false;
2298   PcDesc* pd = pc_desc_at(return_pc);
2299   if (pd == NULL)
2300     return false;
2301   return pd->is_method_handle_invoke();
2302 }
2303 
2304 
2305 // -----------------------------------------------------------------------------
2306 // Verification
2307 
2308 class VerifyOopsClosure: public OopClosure {
2309   nmethod* _nm;
2310   bool     _ok;
2311 public:
2312   VerifyOopsClosure(nmethod* nm) : _nm(nm), _ok(true) { }
2313   bool ok() { return _ok; }
2314   virtual void do_oop(oop* p) {
2315     if ((*p) == NULL || (*p)->is_oop())  return;
2316     if (_ok) {
2317       _nm->print_nmethod(true);
2318       _ok = false;
2319     }
2320     tty->print_cr("*** non-oop "PTR_FORMAT" found at "PTR_FORMAT" (offset %d)",
2321                   (intptr_t)(*p), (intptr_t)p, (int)((intptr_t)p - (intptr_t)_nm));
2322   }
2323   virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
2324 };
2325 
2326 void nmethod::verify() {
2327 
2328   // Hmm. OSR methods can be deopted but not marked as zombie or not_entrant
2329   // seems odd.
2330 
2331   if( is_zombie() || is_not_entrant() )
2332     return;
2333 
2334   // Make sure all the entry points are correctly aligned for patching.
2335   NativeJump::check_verified_entry_alignment(entry_point(), verified_entry_point());
2336 
2337   // assert(method()->is_oop(), "must be valid");
2338 
2339   ResourceMark rm;
2340 
2341   if (!CodeCache::contains(this)) {
2342     fatal(err_msg("nmethod at " INTPTR_FORMAT " not in zone", this));
2343   }
2344 
2345   if(is_native_method() )
2346     return;
2347 
2348   nmethod* nm = CodeCache::find_nmethod(verified_entry_point());
2349   if (nm != this) {
2350     fatal(err_msg("findNMethod did not find this nmethod (" INTPTR_FORMAT ")",
2351                   this));
2352   }
2353 
2354   for (PcDesc* p = scopes_pcs_begin(); p < scopes_pcs_end(); p++) {
2355     if (! p->verify(this)) {
2356       tty->print_cr("\t\tin nmethod at " INTPTR_FORMAT " (pcs)", this);
2357     }
2358   }
2359 
2360   VerifyOopsClosure voc(this);
2361   oops_do(&voc);
2362   assert(voc.ok(), "embedded oops must be OK");
2363   verify_scavenge_root_oops();
2364 
2365   verify_scopes();
2366 }
2367 
2368 
2369 void nmethod::verify_interrupt_point(address call_site) {
2370   // This code does not work in release mode since
2371   // owns_lock only is available in debug mode.
2372   CompiledIC* ic = NULL;
2373   Thread *cur = Thread::current();
2374   if (CompiledIC_lock->owner() == cur ||
2375       ((cur->is_VM_thread() || cur->is_ConcurrentGC_thread()) &&
2376        SafepointSynchronize::is_at_safepoint())) {
2377     ic = CompiledIC_at(this, call_site);
2378     CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops());
2379   } else {
2380     MutexLocker ml_verify (CompiledIC_lock);
2381     ic = CompiledIC_at(this, call_site);
2382   }
2383   PcDesc* pd = pc_desc_at(ic->end_of_call());
2384   assert(pd != NULL, "PcDesc must exist");
2385   for (ScopeDesc* sd = new ScopeDesc(this, pd->scope_decode_offset(),
2386                                      pd->obj_decode_offset(), pd->should_reexecute(),
2387                                      pd->return_oop());
2388        !sd->is_top(); sd = sd->sender()) {
2389     sd->verify();
2390   }
2391 }
2392 
2393 void nmethod::verify_scopes() {
2394   if( !method() ) return;       // Runtime stubs have no scope
2395   if (method()->is_native()) return; // Ignore stub methods.
2396   // iterate through all interrupt point
2397   // and verify the debug information is valid.
2398   RelocIterator iter((nmethod*)this);
2399   while (iter.next()) {
2400     address stub = NULL;
2401     switch (iter.type()) {
2402       case relocInfo::virtual_call_type:
2403         verify_interrupt_point(iter.addr());
2404         break;
2405       case relocInfo::opt_virtual_call_type:
2406         stub = iter.opt_virtual_call_reloc()->static_stub();
2407         verify_interrupt_point(iter.addr());
2408         break;
2409       case relocInfo::static_call_type:
2410         stub = iter.static_call_reloc()->static_stub();
2411         //verify_interrupt_point(iter.addr());
2412         break;
2413       case relocInfo::runtime_call_type:
2414         address destination = iter.reloc()->value();
2415         // Right now there is no way to find out which entries support
2416         // an interrupt point.  It would be nice if we had this
2417         // information in a table.
2418         break;
2419     }
2420     assert(stub == NULL || stub_contains(stub), "static call stub outside stub section");
2421   }
2422 }
2423 
2424 
2425 // -----------------------------------------------------------------------------
2426 // Non-product code
2427 #ifndef PRODUCT
2428 
2429 class DebugScavengeRoot: public OopClosure {
2430   nmethod* _nm;
2431   bool     _ok;
2432 public:
2433   DebugScavengeRoot(nmethod* nm) : _nm(nm), _ok(true) { }
2434   bool ok() { return _ok; }
2435   virtual void do_oop(oop* p) {
2436     if ((*p) == NULL || !(*p)->is_scavengable())  return;
2437     if (_ok) {
2438       _nm->print_nmethod(true);
2439       _ok = false;
2440     }
2441     tty->print_cr("*** scavengable oop "PTR_FORMAT" found at "PTR_FORMAT" (offset %d)",
2442                   (intptr_t)(*p), (intptr_t)p, (int)((intptr_t)p - (intptr_t)_nm));
2443     (*p)->print();
2444   }
2445   virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
2446 };
2447 
2448 void nmethod::verify_scavenge_root_oops() {
2449   if (!on_scavenge_root_list()) {
2450     // Actually look inside, to verify the claim that it's clean.
2451     DebugScavengeRoot debug_scavenge_root(this);
2452     oops_do(&debug_scavenge_root);
2453     if (!debug_scavenge_root.ok())
2454       fatal("found an unadvertised bad scavengable oop in the code cache");
2455   }
2456   assert(scavenge_root_not_marked(), "");
2457 }
2458 
2459 #endif // PRODUCT
2460 
2461 // Printing operations
2462 
2463 void nmethod::print() const {
2464   ResourceMark rm;
2465   ttyLocker ttyl;   // keep the following output all in one block
2466 
2467   tty->print("Compiled method ");
2468 
2469   if (is_compiled_by_c1()) {
2470     tty->print("(c1) ");
2471   } else if (is_compiled_by_c2()) {
2472     tty->print("(c2) ");
2473   } else if (is_compiled_by_shark()) {
2474     tty->print("(shark) ");
2475   } else {
2476     tty->print("(nm) ");
2477   }
2478 
2479   print_on(tty, NULL);
2480 
2481   if (WizardMode) {
2482     tty->print("((nmethod*) "INTPTR_FORMAT ") ", this);
2483     tty->print(" for method " INTPTR_FORMAT , (address)method());
2484     tty->print(" { ");
2485     if (is_in_use())      tty->print("in_use ");
2486     if (is_not_entrant()) tty->print("not_entrant ");
2487     if (is_zombie())      tty->print("zombie ");
2488     if (is_unloaded())    tty->print("unloaded ");
2489     if (on_scavenge_root_list())  tty->print("scavenge_root ");
2490     tty->print_cr("}:");
2491   }
2492   if (size              () > 0) tty->print_cr(" total in heap  [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2493                                               (address)this,
2494                                               (address)this + size(),
2495                                               size());
2496   if (relocation_size   () > 0) tty->print_cr(" relocation     [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2497                                               relocation_begin(),
2498                                               relocation_end(),
2499                                               relocation_size());
2500   if (consts_size       () > 0) tty->print_cr(" constants      [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2501                                               consts_begin(),
2502                                               consts_end(),
2503                                               consts_size());
2504   if (insts_size        () > 0) tty->print_cr(" main code      [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2505                                               insts_begin(),
2506                                               insts_end(),
2507                                               insts_size());
2508   if (stub_size         () > 0) tty->print_cr(" stub code      [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2509                                               stub_begin(),
2510                                               stub_end(),
2511                                               stub_size());
2512   if (oops_size         () > 0) tty->print_cr(" oops           [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2513                                               oops_begin(),
2514                                               oops_end(),
2515                                               oops_size());
2516   if (metadata_size      () > 0) tty->print_cr(" metadata       [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2517                                               metadata_begin(),
2518                                               metadata_end(),
2519                                               metadata_size());
2520   if (scopes_data_size  () > 0) tty->print_cr(" scopes data    [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2521                                               scopes_data_begin(),
2522                                               scopes_data_end(),
2523                                               scopes_data_size());
2524   if (scopes_pcs_size   () > 0) tty->print_cr(" scopes pcs     [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2525                                               scopes_pcs_begin(),
2526                                               scopes_pcs_end(),
2527                                               scopes_pcs_size());
2528   if (dependencies_size () > 0) tty->print_cr(" dependencies   [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2529                                               dependencies_begin(),
2530                                               dependencies_end(),
2531                                               dependencies_size());
2532   if (handler_table_size() > 0) tty->print_cr(" handler table  [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2533                                               handler_table_begin(),
2534                                               handler_table_end(),
2535                                               handler_table_size());
2536   if (nul_chk_table_size() > 0) tty->print_cr(" nul chk table  [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2537                                               nul_chk_table_begin(),
2538                                               nul_chk_table_end(),
2539                                               nul_chk_table_size());
2540 }
2541 
2542 void nmethod::print_code() {
2543   HandleMark hm;
2544   ResourceMark m;
2545   Disassembler::decode(this);
2546 }
2547 
2548 
2549 #ifndef PRODUCT
2550 
2551 void nmethod::print_scopes() {
2552   // Find the first pc desc for all scopes in the code and print it.
2553   ResourceMark rm;
2554   for (PcDesc* p = scopes_pcs_begin(); p < scopes_pcs_end(); p++) {
2555     if (p->scope_decode_offset() == DebugInformationRecorder::serialized_null)
2556       continue;
2557 
2558     ScopeDesc* sd = scope_desc_at(p->real_pc(this));
2559     sd->print_on(tty, p);
2560   }
2561 }
2562 
2563 void nmethod::print_dependencies() {
2564   ResourceMark rm;
2565   ttyLocker ttyl;   // keep the following output all in one block
2566   tty->print_cr("Dependencies:");
2567   for (Dependencies::DepStream deps(this); deps.next(); ) {
2568     deps.print_dependency();
2569     Klass* ctxk = deps.context_type();
2570     if (ctxk != NULL) {
2571       Klass* k = Klass::cast(ctxk);
2572       if (k->oop_is_instance() && ((InstanceKlass*)k)->is_dependent_nmethod(this)) {
2573         tty->print_cr("   [nmethod<=klass]%s", k->external_name());
2574       }
2575     }
2576     deps.log_dependency();  // put it into the xml log also
2577   }
2578 }
2579 
2580 
2581 void nmethod::print_relocations() {
2582   ResourceMark m;       // in case methods get printed via the debugger
2583   tty->print_cr("relocations:");
2584   RelocIterator iter(this);
2585   iter.print();
2586   if (UseRelocIndex) {
2587     jint* index_end   = (jint*)relocation_end() - 1;
2588     jint  index_size  = *index_end;
2589     jint* index_start = (jint*)( (address)index_end - index_size );
2590     tty->print_cr("    index @" INTPTR_FORMAT ": index_size=%d", index_start, index_size);
2591     if (index_size > 0) {
2592       jint* ip;
2593       for (ip = index_start; ip+2 <= index_end; ip += 2)
2594         tty->print_cr("  (%d %d) addr=" INTPTR_FORMAT " @" INTPTR_FORMAT,
2595                       ip[0],
2596                       ip[1],
2597                       header_end()+ip[0],
2598                       relocation_begin()-1+ip[1]);
2599       for (; ip < index_end; ip++)
2600         tty->print_cr("  (%d ?)", ip[0]);
2601       tty->print_cr("          @" INTPTR_FORMAT ": index_size=%d", ip, *ip++);
2602       tty->print_cr("reloc_end @" INTPTR_FORMAT ":", ip);
2603     }
2604   }
2605 }
2606 
2607 
2608 void nmethod::print_pcs() {
2609   ResourceMark m;       // in case methods get printed via debugger
2610   tty->print_cr("pc-bytecode offsets:");
2611   for (PcDesc* p = scopes_pcs_begin(); p < scopes_pcs_end(); p++) {
2612     p->print(this);
2613   }
2614 }
2615 
2616 #endif // PRODUCT
2617 
2618 const char* nmethod::reloc_string_for(u_char* begin, u_char* end) {
2619   RelocIterator iter(this, begin, end);
2620   bool have_one = false;
2621   while (iter.next()) {
2622     have_one = true;
2623     switch (iter.type()) {
2624         case relocInfo::none:                  return "no_reloc";
2625         case relocInfo::oop_type: {
2626           stringStream st;
2627           oop_Relocation* r = iter.oop_reloc();
2628           oop obj = r->oop_value();
2629           st.print("oop(");
2630           if (obj == NULL) st.print("NULL");
2631           else obj->print_value_on(&st);
2632           st.print(")");
2633           return st.as_string();
2634         }
2635         case relocInfo::metadata_type: {
2636           stringStream st;
2637           metadata_Relocation* r = iter.metadata_reloc();
2638           Metadata* obj = r->metadata_value();
2639           st.print("metadata(");
2640           if (obj == NULL) st.print("NULL");
2641           else obj->print_value_on(&st);
2642           st.print(")");
2643           return st.as_string();
2644         }
2645         case relocInfo::virtual_call_type:     return "virtual_call";
2646         case relocInfo::opt_virtual_call_type: return "optimized virtual_call";
2647         case relocInfo::static_call_type:      return "static_call";
2648         case relocInfo::static_stub_type:      return "static_stub";
2649         case relocInfo::runtime_call_type:     return "runtime_call";
2650         case relocInfo::external_word_type:    return "external_word";
2651         case relocInfo::internal_word_type:    return "internal_word";
2652         case relocInfo::section_word_type:     return "section_word";
2653         case relocInfo::poll_type:             return "poll";
2654         case relocInfo::poll_return_type:      return "poll_return";
2655         case relocInfo::type_mask:             return "type_bit_mask";
2656     }
2657   }
2658   return have_one ? "other" : NULL;
2659 }
2660 
2661 // Return a the last scope in (begin..end]
2662 ScopeDesc* nmethod::scope_desc_in(address begin, address end) {
2663   PcDesc* p = pc_desc_near(begin+1);
2664   if (p != NULL && p->real_pc(this) <= end) {
2665     return new ScopeDesc(this, p->scope_decode_offset(),
2666                          p->obj_decode_offset(), p->should_reexecute(),
2667                          p->return_oop());
2668   }
2669   return NULL;
2670 }
2671 
2672 void nmethod::print_nmethod_labels(outputStream* stream, address block_begin) {
2673   if (block_begin == entry_point())             stream->print_cr("[Entry Point]");
2674   if (block_begin == verified_entry_point())    stream->print_cr("[Verified Entry Point]");
2675   if (block_begin == exception_begin())         stream->print_cr("[Exception Handler]");
2676   if (block_begin == stub_begin())              stream->print_cr("[Stub Code]");
2677   if (block_begin == deopt_handler_begin())     stream->print_cr("[Deopt Handler Code]");
2678 
2679   if (has_method_handle_invokes())
2680     if (block_begin == deopt_mh_handler_begin())  stream->print_cr("[Deopt MH Handler Code]");
2681 
2682   if (block_begin == consts_begin())            stream->print_cr("[Constants]");
2683 
2684   if (block_begin == entry_point()) {
2685     methodHandle m = method();
2686     if (m.not_null()) {
2687       stream->print("  # ");
2688       m->print_value_on(stream);
2689       stream->cr();
2690     }
2691     if (m.not_null() && !is_osr_method()) {
2692       ResourceMark rm;
2693       int sizeargs = m->size_of_parameters();
2694       BasicType* sig_bt = NEW_RESOURCE_ARRAY(BasicType, sizeargs);
2695       VMRegPair* regs   = NEW_RESOURCE_ARRAY(VMRegPair, sizeargs);
2696       {
2697         int sig_index = 0;
2698         if (!m->is_static())
2699           sig_bt[sig_index++] = T_OBJECT; // 'this'
2700         for (SignatureStream ss(m->signature()); !ss.at_return_type(); ss.next()) {
2701           BasicType t = ss.type();
2702           sig_bt[sig_index++] = t;
2703           if (type2size[t] == 2) {
2704             sig_bt[sig_index++] = T_VOID;
2705           } else {
2706             assert(type2size[t] == 1, "size is 1 or 2");
2707           }
2708         }
2709         assert(sig_index == sizeargs, "");
2710       }
2711       const char* spname = "sp"; // make arch-specific?
2712       intptr_t out_preserve = SharedRuntime::java_calling_convention(sig_bt, regs, sizeargs, false);
2713       int stack_slot_offset = this->frame_size() * wordSize;
2714       int tab1 = 14, tab2 = 24;
2715       int sig_index = 0;
2716       int arg_index = (m->is_static() ? 0 : -1);
2717       bool did_old_sp = false;
2718       for (SignatureStream ss(m->signature()); !ss.at_return_type(); ) {
2719         bool at_this = (arg_index == -1);
2720         bool at_old_sp = false;
2721         BasicType t = (at_this ? T_OBJECT : ss.type());
2722         assert(t == sig_bt[sig_index], "sigs in sync");
2723         if (at_this)
2724           stream->print("  # this: ");
2725         else
2726           stream->print("  # parm%d: ", arg_index);
2727         stream->move_to(tab1);
2728         VMReg fst = regs[sig_index].first();
2729         VMReg snd = regs[sig_index].second();
2730         if (fst->is_reg()) {
2731           stream->print("%s", fst->name());
2732           if (snd->is_valid())  {
2733             stream->print(":%s", snd->name());
2734           }
2735         } else if (fst->is_stack()) {
2736           int offset = fst->reg2stack() * VMRegImpl::stack_slot_size + stack_slot_offset;
2737           if (offset == stack_slot_offset)  at_old_sp = true;
2738           stream->print("[%s+0x%x]", spname, offset);
2739         } else {
2740           stream->print("reg%d:%d??", (int)(intptr_t)fst, (int)(intptr_t)snd);
2741         }
2742         stream->print(" ");
2743         stream->move_to(tab2);
2744         stream->print("= ");
2745         if (at_this) {
2746           m->method_holder()->print_value_on(stream);
2747         } else {
2748           bool did_name = false;
2749           if (!at_this && ss.is_object()) {
2750             Symbol* name = ss.as_symbol_or_null();
2751             if (name != NULL) {
2752               name->print_value_on(stream);
2753               did_name = true;
2754             }
2755           }
2756           if (!did_name)
2757             stream->print("%s", type2name(t));
2758         }
2759         if (at_old_sp) {
2760           stream->print("  (%s of caller)", spname);
2761           did_old_sp = true;
2762         }
2763         stream->cr();
2764         sig_index += type2size[t];
2765         arg_index += 1;
2766         if (!at_this)  ss.next();
2767       }
2768       if (!did_old_sp) {
2769         stream->print("  # ");
2770         stream->move_to(tab1);
2771         stream->print("[%s+0x%x]", spname, stack_slot_offset);
2772         stream->print("  (%s of caller)", spname);
2773         stream->cr();
2774       }
2775     }
2776   }
2777 }
2778 
2779 void nmethod::print_code_comment_on(outputStream* st, int column, u_char* begin, u_char* end) {
2780   // First, find an oopmap in (begin, end].
2781   // We use the odd half-closed interval so that oop maps and scope descs
2782   // which are tied to the byte after a call are printed with the call itself.
2783   address base = code_begin();
2784   OopMapSet* oms = oop_maps();
2785   if (oms != NULL) {
2786     for (int i = 0, imax = oms->size(); i < imax; i++) {
2787       OopMap* om = oms->at(i);
2788       address pc = base + om->offset();
2789       if (pc > begin) {
2790         if (pc <= end) {
2791           st->move_to(column);
2792           st->print("; ");
2793           om->print_on(st);
2794         }
2795         break;
2796       }
2797     }
2798   }
2799 
2800   // Print any debug info present at this pc.
2801   ScopeDesc* sd  = scope_desc_in(begin, end);
2802   if (sd != NULL) {
2803     st->move_to(column);
2804     if (sd->bci() == SynchronizationEntryBCI) {
2805       st->print(";*synchronization entry");
2806     } else {
2807       if (sd->method() == NULL) {
2808         st->print("method is NULL");
2809       } else if (sd->method()->is_native()) {
2810         st->print("method is native");
2811       } else {
2812         Bytecodes::Code bc = sd->method()->java_code_at(sd->bci());
2813         st->print(";*%s", Bytecodes::name(bc));
2814         switch (bc) {
2815         case Bytecodes::_invokevirtual:
2816         case Bytecodes::_invokespecial:
2817         case Bytecodes::_invokestatic:
2818         case Bytecodes::_invokeinterface:
2819           {
2820             Bytecode_invoke invoke(sd->method(), sd->bci());
2821             st->print(" ");
2822             if (invoke.name() != NULL)
2823               invoke.name()->print_symbol_on(st);
2824             else
2825               st->print("<UNKNOWN>");
2826             break;
2827           }
2828         case Bytecodes::_getfield:
2829         case Bytecodes::_putfield:
2830         case Bytecodes::_getstatic:
2831         case Bytecodes::_putstatic:
2832           {
2833             Bytecode_field field(sd->method(), sd->bci());
2834             st->print(" ");
2835             if (field.name() != NULL)
2836               field.name()->print_symbol_on(st);
2837             else
2838               st->print("<UNKNOWN>");
2839           }
2840         }
2841       }
2842     }
2843 
2844     // Print all scopes
2845     for (;sd != NULL; sd = sd->sender()) {
2846       st->move_to(column);
2847       st->print("; -");
2848       if (sd->method() == NULL) {
2849         st->print("method is NULL");
2850       } else {
2851         sd->method()->print_short_name(st);
2852       }
2853       int lineno = sd->method()->line_number_from_bci(sd->bci());
2854       if (lineno != -1) {
2855         st->print("@%d (line %d)", sd->bci(), lineno);
2856       } else {
2857         st->print("@%d", sd->bci());
2858       }
2859       st->cr();
2860     }
2861   }
2862 
2863   // Print relocation information
2864   const char* str = reloc_string_for(begin, end);
2865   if (str != NULL) {
2866     if (sd != NULL) st->cr();
2867     st->move_to(column);
2868     st->print(";   {%s}", str);
2869   }
2870   int cont_offset = ImplicitExceptionTable(this).at(begin - code_begin());
2871   if (cont_offset != 0) {
2872     st->move_to(column);
2873     st->print("; implicit exception: dispatches to " INTPTR_FORMAT, code_begin() + cont_offset);
2874   }
2875 
2876 }
2877 
2878 #ifndef PRODUCT
2879 
2880 void nmethod::print_value_on(outputStream* st) const {
2881   st->print("nmethod");
2882   print_on(st, NULL);
2883 }
2884 
2885 void nmethod::print_calls(outputStream* st) {
2886   RelocIterator iter(this);
2887   while (iter.next()) {
2888     switch (iter.type()) {
2889     case relocInfo::virtual_call_type:
2890     case relocInfo::opt_virtual_call_type: {
2891       VerifyMutexLocker mc(CompiledIC_lock);
2892       CompiledIC_at(iter.reloc())->print();
2893       break;
2894     }
2895     case relocInfo::static_call_type:
2896       st->print_cr("Static call at " INTPTR_FORMAT, iter.reloc()->addr());
2897       compiledStaticCall_at(iter.reloc())->print();
2898       break;
2899     }
2900   }
2901 }
2902 
2903 void nmethod::print_handler_table() {
2904   ExceptionHandlerTable(this).print();
2905 }
2906 
2907 void nmethod::print_nul_chk_table() {
2908   ImplicitExceptionTable(this).print(code_begin());
2909 }
2910 
2911 void nmethod::print_statistics() {
2912   ttyLocker ttyl;
2913   if (xtty != NULL)  xtty->head("statistics type='nmethod'");
2914   nmethod_stats.print_native_nmethod_stats();
2915   nmethod_stats.print_nmethod_stats();
2916   DebugInformationRecorder::print_statistics();
2917   nmethod_stats.print_pc_stats();
2918   Dependencies::print_statistics();
2919   if (xtty != NULL)  xtty->tail("statistics");
2920 }
2921 
2922 #endif // PRODUCT