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   _has_wide_vectors           = 0;
 467   _marked_for_deoptimization  = 0;
 468   _lock_count                 = 0;
 469   _stack_traversal_mark       = 0;
 470   _unload_reported            = false;           // jvmti state
 471 
 472 #ifdef ASSERT
 473   _oops_are_stale             = false;
 474 #endif
 475 
 476   _oops_do_mark_link       = NULL;
 477   _jmethod_id              = NULL;
 478   _osr_link                = NULL;
 479   _scavenge_root_link      = NULL;
 480   _scavenge_root_state     = 0;
 481   _saved_nmethod_link      = NULL;
 482   _compiler                = NULL;
 483 
 484 #ifdef HAVE_DTRACE_H
 485   _trap_offset             = 0;
 486 #endif // def HAVE_DTRACE_H
 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) nmethod(method(), native_nmethod_size,
 508                                             compile_id, &offsets,
 509                                             code_buffer, frame_size,
 510                                             basic_lock_owner_sp_offset,
 511                                             basic_lock_sp_offset, 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   }
 517   // verify nmethod
 518   debug_only(if (nm) nm->verify();) // might block
 519 
 520   if (nm != NULL) {
 521     nm->log_new_nmethod();
 522   }
 523 
 524   return nm;
 525 }
 526 
 527 #ifdef HAVE_DTRACE_H
 528 nmethod* nmethod::new_dtrace_nmethod(methodHandle method,
 529                                      CodeBuffer *code_buffer,
 530                                      int vep_offset,
 531                                      int trap_offset,
 532                                      int frame_complete,
 533                                      int frame_size) {
 534   code_buffer->finalize_oop_references(method);
 535   // create nmethod
 536   nmethod* nm = NULL;
 537   {
 538     MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
 539     int nmethod_size = allocation_size(code_buffer, sizeof(nmethod));
 540     CodeOffsets offsets;
 541     offsets.set_value(CodeOffsets::Verified_Entry, vep_offset);
 542     offsets.set_value(CodeOffsets::Dtrace_trap, trap_offset);
 543     offsets.set_value(CodeOffsets::Frame_Complete, frame_complete);
 544 
 545     nm = new (nmethod_size) nmethod(method(), nmethod_size,
 546                                     &offsets, code_buffer, frame_size);
 547 
 548     NOT_PRODUCT(if (nm != NULL)  nmethod_stats.note_nmethod(nm));
 549     if (PrintAssembly && nm != NULL) {
 550       Disassembler::decode(nm);
 551     }
 552   }
 553   // verify nmethod
 554   debug_only(if (nm) nm->verify();) // might block
 555 
 556   if (nm != NULL) {
 557     nm->log_new_nmethod();
 558   }
 559 
 560   return nm;
 561 }
 562 
 563 #endif // def HAVE_DTRACE_H
 564 
 565 nmethod* nmethod::new_nmethod(methodHandle method,
 566   int compile_id,
 567   int entry_bci,
 568   CodeOffsets* offsets,
 569   int orig_pc_offset,
 570   DebugInformationRecorder* debug_info,
 571   Dependencies* dependencies,
 572   CodeBuffer* code_buffer, int frame_size,
 573   OopMapSet* oop_maps,
 574   ExceptionHandlerTable* handler_table,
 575   ImplicitExceptionTable* nul_chk_table,
 576   AbstractCompiler* compiler,
 577   int comp_level
 578 )
 579 {
 580   assert(debug_info->oop_recorder() == code_buffer->oop_recorder(), "shared OR");
 581   code_buffer->finalize_oop_references(method);
 582   // create nmethod
 583   nmethod* nm = NULL;
 584   { MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
 585     int nmethod_size =
 586       allocation_size(code_buffer, sizeof(nmethod))
 587       + adjust_pcs_size(debug_info->pcs_size())
 588       + round_to(dependencies->size_in_bytes() , oopSize)
 589       + round_to(handler_table->size_in_bytes(), oopSize)
 590       + round_to(nul_chk_table->size_in_bytes(), oopSize)
 591       + round_to(debug_info->data_size()       , oopSize);
 592 
 593     nm = new (nmethod_size)
 594     nmethod(method(), nmethod_size, compile_id, entry_bci, offsets,
 595             orig_pc_offset, debug_info, dependencies, code_buffer, frame_size,
 596             oop_maps,
 597             handler_table,
 598             nul_chk_table,
 599             compiler,
 600             comp_level);
 601 
 602     if (nm != NULL) {
 603       // To make dependency checking during class loading fast, record
 604       // the nmethod dependencies in the classes it is dependent on.
 605       // This allows the dependency checking code to simply walk the
 606       // class hierarchy above the loaded class, checking only nmethods
 607       // which are dependent on those classes.  The slow way is to
 608       // check every nmethod for dependencies which makes it linear in
 609       // the number of methods compiled.  For applications with a lot
 610       // classes the slow way is too slow.
 611       for (Dependencies::DepStream deps(nm); deps.next(); ) {
 612         Klass* klass = deps.context_type();
 613         if (klass == NULL) {
 614           continue;  // ignore things like evol_method
 615         }
 616 
 617         // record this nmethod as dependent on this klass
 618         InstanceKlass::cast(klass)->add_dependent_nmethod(nm);
 619       }
 620     }
 621     NOT_PRODUCT(if (nm != NULL)  nmethod_stats.note_nmethod(nm));
 622     if (PrintAssembly && nm != NULL) {
 623       Disassembler::decode(nm);
 624     }
 625   }
 626 
 627   // verify nmethod
 628   debug_only(if (nm) nm->verify();) // might block
 629 
 630   if (nm != NULL) {
 631     nm->log_new_nmethod();
 632   }
 633 
 634   // done
 635   return nm;
 636 }
 637 
 638 
 639 // For native wrappers
 640 nmethod::nmethod(
 641   Method* method,
 642   int nmethod_size,
 643   int compile_id,
 644   CodeOffsets* offsets,
 645   CodeBuffer* code_buffer,
 646   int frame_size,
 647   ByteSize basic_lock_owner_sp_offset,
 648   ByteSize basic_lock_sp_offset,
 649   OopMapSet* oop_maps )
 650   : CodeBlob("native nmethod", code_buffer, sizeof(nmethod),
 651              nmethod_size, offsets->value(CodeOffsets::Frame_Complete), frame_size, oop_maps),
 652   _native_receiver_sp_offset(basic_lock_owner_sp_offset),
 653   _native_basic_lock_sp_offset(basic_lock_sp_offset)
 654 {
 655   {
 656     debug_only(No_Safepoint_Verifier nsv;)
 657     assert_locked_or_safepoint(CodeCache_lock);
 658 
 659     init_defaults();
 660     _method                  = method;
 661     _entry_bci               = InvocationEntryBci;
 662     // We have no exception handler or deopt handler make the
 663     // values something that will never match a pc like the nmethod vtable entry
 664     _exception_offset        = 0;
 665     _deoptimize_offset       = 0;
 666     _deoptimize_mh_offset    = 0;
 667     _orig_pc_offset          = 0;
 668 
 669     _consts_offset           = data_offset();
 670     _stub_offset             = data_offset();
 671     _oops_offset             = data_offset();
 672     _metadata_offset         = _oops_offset         + round_to(code_buffer->total_oop_size(), oopSize);
 673     _scopes_data_offset      = _metadata_offset     + round_to(code_buffer->total_metadata_size(), wordSize);
 674     _scopes_pcs_offset       = _scopes_data_offset;
 675     _dependencies_offset     = _scopes_pcs_offset;
 676     _handler_table_offset    = _dependencies_offset;
 677     _nul_chk_table_offset    = _handler_table_offset;
 678     _nmethod_end_offset      = _nul_chk_table_offset;
 679     _compile_id              = compile_id;
 680     _comp_level              = CompLevel_none;
 681     _entry_point             = code_begin()          + offsets->value(CodeOffsets::Entry);
 682     _verified_entry_point    = code_begin()          + offsets->value(CodeOffsets::Verified_Entry);
 683     _osr_entry_point         = NULL;
 684     _exception_cache         = NULL;
 685     _pc_desc_cache.reset_to(NULL);
 686 
 687     code_buffer->copy_values_to(this);
 688     if (ScavengeRootsInCode && detect_scavenge_root_oops()) {
 689       CodeCache::add_scavenge_root_nmethod(this);
 690     }
 691     debug_only(verify_scavenge_root_oops());
 692     CodeCache::commit(this);
 693   }
 694 
 695   if (PrintNativeNMethods || PrintDebugInfo || PrintRelocations || PrintDependencies) {
 696     ttyLocker ttyl;  // keep the following output all in one block
 697     // This output goes directly to the tty, not the compiler log.
 698     // To enable tools to match it up with the compilation activity,
 699     // be sure to tag this tty output with the compile ID.
 700     if (xtty != NULL) {
 701       xtty->begin_head("print_native_nmethod");
 702       xtty->method(_method);
 703       xtty->stamp();
 704       xtty->end_head(" address='" INTPTR_FORMAT "'", (intptr_t) this);
 705     }
 706     // print the header part first
 707     print();
 708     // then print the requested information
 709     if (PrintNativeNMethods) {
 710       print_code();
 711       if (oop_maps != NULL) {
 712         oop_maps->print();
 713       }
 714     }
 715     if (PrintRelocations) {
 716       print_relocations();
 717     }
 718     if (xtty != NULL) {
 719       xtty->tail("print_native_nmethod");
 720     }
 721   }
 722 }
 723 
 724 // For dtrace wrappers
 725 #ifdef HAVE_DTRACE_H
 726 nmethod::nmethod(
 727   Method* method,
 728   int nmethod_size,
 729   CodeOffsets* offsets,
 730   CodeBuffer* code_buffer,
 731   int frame_size)
 732   : CodeBlob("dtrace nmethod", code_buffer, sizeof(nmethod),
 733              nmethod_size, offsets->value(CodeOffsets::Frame_Complete), frame_size, NULL),
 734   _native_receiver_sp_offset(in_ByteSize(-1)),
 735   _native_basic_lock_sp_offset(in_ByteSize(-1))
 736 {
 737   {
 738     debug_only(No_Safepoint_Verifier nsv;)
 739     assert_locked_or_safepoint(CodeCache_lock);
 740 
 741     init_defaults();
 742     _method                  = method;
 743     _entry_bci               = InvocationEntryBci;
 744     // We have no exception handler or deopt handler make the
 745     // values something that will never match a pc like the nmethod vtable entry
 746     _exception_offset        = 0;
 747     _deoptimize_offset       = 0;
 748     _deoptimize_mh_offset    = 0;
 749     _unwind_handler_offset   = -1;
 750     _trap_offset             = offsets->value(CodeOffsets::Dtrace_trap);
 751     _orig_pc_offset          = 0;
 752     _consts_offset           = data_offset();
 753     _stub_offset             = data_offset();
 754     _oops_offset             = data_offset();
 755     _metadata_offset         = _oops_offset         + round_to(code_buffer->total_oop_size(), oopSize);
 756     _scopes_data_offset      = _metadata_offset     + round_to(code_buffer->total_metadata_size(), wordSize);
 757     _scopes_pcs_offset       = _scopes_data_offset;
 758     _dependencies_offset     = _scopes_pcs_offset;
 759     _handler_table_offset    = _dependencies_offset;
 760     _nul_chk_table_offset    = _handler_table_offset;
 761     _nmethod_end_offset      = _nul_chk_table_offset;
 762     _compile_id              = 0;  // default
 763     _comp_level              = CompLevel_none;
 764     _entry_point             = code_begin()          + offsets->value(CodeOffsets::Entry);
 765     _verified_entry_point    = code_begin()          + offsets->value(CodeOffsets::Verified_Entry);
 766     _osr_entry_point         = NULL;
 767     _exception_cache         = NULL;
 768     _pc_desc_cache.reset_to(NULL);
 769 
 770     code_buffer->copy_values_to(this);
 771     debug_only(verify_scavenge_root_oops());
 772     CodeCache::commit(this);
 773   }
 774 
 775   if (PrintNMethods || PrintDebugInfo || PrintRelocations || PrintDependencies) {
 776     ttyLocker ttyl;  // keep the following output all in one block
 777     // This output goes directly to the tty, not the compiler log.
 778     // To enable tools to match it up with the compilation activity,
 779     // be sure to tag this tty output with the compile ID.
 780     if (xtty != NULL) {
 781       xtty->begin_head("print_dtrace_nmethod");
 782       xtty->method(_method);
 783       xtty->stamp();
 784       xtty->end_head(" address='" INTPTR_FORMAT "'", (intptr_t) this);
 785     }
 786     // print the header part first
 787     print();
 788     // then print the requested information
 789     if (PrintNMethods) {
 790       print_code();
 791     }
 792     if (PrintRelocations) {
 793       print_relocations();
 794     }
 795     if (xtty != NULL) {
 796       xtty->tail("print_dtrace_nmethod");
 797     }
 798   }
 799 }
 800 #endif // def HAVE_DTRACE_H
 801 
 802 void* nmethod::operator new(size_t size, int nmethod_size) throw () {
 803   // Not critical, may return null if there is too little continuous memory
 804   return CodeCache::allocate(nmethod_size);
 805 }
 806 
 807 nmethod::nmethod(
 808   Method* method,
 809   int nmethod_size,
 810   int compile_id,
 811   int entry_bci,
 812   CodeOffsets* offsets,
 813   int orig_pc_offset,
 814   DebugInformationRecorder* debug_info,
 815   Dependencies* dependencies,
 816   CodeBuffer *code_buffer,
 817   int frame_size,
 818   OopMapSet* oop_maps,
 819   ExceptionHandlerTable* handler_table,
 820   ImplicitExceptionTable* nul_chk_table,
 821   AbstractCompiler* compiler,
 822   int comp_level
 823   )
 824   : CodeBlob("nmethod", code_buffer, sizeof(nmethod),
 825              nmethod_size, offsets->value(CodeOffsets::Frame_Complete), frame_size, oop_maps),
 826   _native_receiver_sp_offset(in_ByteSize(-1)),
 827   _native_basic_lock_sp_offset(in_ByteSize(-1))
 828 {
 829   assert(debug_info->oop_recorder() == code_buffer->oop_recorder(), "shared OR");
 830   {
 831     debug_only(No_Safepoint_Verifier nsv;)
 832     assert_locked_or_safepoint(CodeCache_lock);
 833 
 834     init_defaults();
 835     _method                  = method;
 836     _entry_bci               = entry_bci;
 837     _compile_id              = compile_id;
 838     _comp_level              = comp_level;
 839     _compiler                = compiler;
 840     _orig_pc_offset          = orig_pc_offset;
 841 
 842     // Section offsets
 843     _consts_offset           = content_offset()      + code_buffer->total_offset_of(code_buffer->consts());
 844     _stub_offset             = content_offset()      + code_buffer->total_offset_of(code_buffer->stubs());
 845 
 846     // Exception handler and deopt handler are in the stub section
 847     assert(offsets->value(CodeOffsets::Exceptions) != -1, "must be set");
 848     assert(offsets->value(CodeOffsets::Deopt     ) != -1, "must be set");
 849     _exception_offset        = _stub_offset          + offsets->value(CodeOffsets::Exceptions);
 850     _deoptimize_offset       = _stub_offset          + offsets->value(CodeOffsets::Deopt);
 851     if (offsets->value(CodeOffsets::DeoptMH) != -1) {
 852       _deoptimize_mh_offset  = _stub_offset          + offsets->value(CodeOffsets::DeoptMH);
 853     } else {
 854       _deoptimize_mh_offset  = -1;
 855     }
 856     if (offsets->value(CodeOffsets::UnwindHandler) != -1) {
 857       _unwind_handler_offset = code_offset()         + offsets->value(CodeOffsets::UnwindHandler);
 858     } else {
 859       _unwind_handler_offset = -1;
 860     }
 861 
 862     _oops_offset             = data_offset();
 863     _metadata_offset         = _oops_offset          + round_to(code_buffer->total_oop_size(), oopSize);
 864     _scopes_data_offset      = _metadata_offset      + round_to(code_buffer->total_metadata_size(), wordSize);
 865 
 866     _scopes_pcs_offset       = _scopes_data_offset   + round_to(debug_info->data_size       (), oopSize);
 867     _dependencies_offset     = _scopes_pcs_offset    + adjust_pcs_size(debug_info->pcs_size());
 868     _handler_table_offset    = _dependencies_offset  + round_to(dependencies->size_in_bytes (), oopSize);
 869     _nul_chk_table_offset    = _handler_table_offset + round_to(handler_table->size_in_bytes(), oopSize);
 870     _nmethod_end_offset      = _nul_chk_table_offset + round_to(nul_chk_table->size_in_bytes(), oopSize);
 871 
 872     _entry_point             = code_begin()          + offsets->value(CodeOffsets::Entry);
 873     _verified_entry_point    = code_begin()          + offsets->value(CodeOffsets::Verified_Entry);
 874     _osr_entry_point         = code_begin()          + offsets->value(CodeOffsets::OSR_Entry);
 875     _exception_cache         = NULL;
 876     _pc_desc_cache.reset_to(scopes_pcs_begin());
 877 
 878     // Copy contents of ScopeDescRecorder to nmethod
 879     code_buffer->copy_values_to(this);
 880     debug_info->copy_to(this);
 881     dependencies->copy_to(this);
 882     if (ScavengeRootsInCode && detect_scavenge_root_oops()) {
 883       CodeCache::add_scavenge_root_nmethod(this);
 884     }
 885     debug_only(verify_scavenge_root_oops());
 886 
 887     CodeCache::commit(this);
 888 
 889     // Copy contents of ExceptionHandlerTable to nmethod
 890     handler_table->copy_to(this);
 891     nul_chk_table->copy_to(this);
 892 
 893     // we use the information of entry points to find out if a method is
 894     // static or non static
 895     assert(compiler->is_c2() ||
 896            _method->is_static() == (entry_point() == _verified_entry_point),
 897            " entry points must be same for static methods and vice versa");
 898   }
 899 
 900   bool printnmethods = PrintNMethods
 901     || CompilerOracle::should_print(_method)
 902     || CompilerOracle::has_option_string(_method, "PrintNMethods");
 903   if (printnmethods || PrintDebugInfo || PrintRelocations || PrintDependencies || PrintExceptionHandlers) {
 904     print_nmethod(printnmethods);
 905   }
 906 }
 907 
 908 
 909 // Print a short set of xml attributes to identify this nmethod.  The
 910 // output should be embedded in some other element.
 911 void nmethod::log_identity(xmlStream* log) const {
 912   log->print(" compile_id='%d'", compile_id());
 913   const char* nm_kind = compile_kind();
 914   if (nm_kind != NULL)  log->print(" compile_kind='%s'", nm_kind);
 915   if (compiler() != NULL) {
 916     log->print(" compiler='%s'", compiler()->name());
 917   }
 918   if (TieredCompilation) {
 919     log->print(" level='%d'", comp_level());
 920   }
 921 }
 922 
 923 
 924 #define LOG_OFFSET(log, name)                    \
 925   if ((intptr_t)name##_end() - (intptr_t)name##_begin()) \
 926     log->print(" " XSTR(name) "_offset='%d'"    , \
 927                (intptr_t)name##_begin() - (intptr_t)this)
 928 
 929 
 930 void nmethod::log_new_nmethod() const {
 931   if (LogCompilation && xtty != NULL) {
 932     ttyLocker ttyl;
 933     HandleMark hm;
 934     xtty->begin_elem("nmethod");
 935     log_identity(xtty);
 936     xtty->print(" entry='" INTPTR_FORMAT "' size='%d'", code_begin(), size());
 937     xtty->print(" address='" INTPTR_FORMAT "'", (intptr_t) this);
 938 
 939     LOG_OFFSET(xtty, relocation);
 940     LOG_OFFSET(xtty, consts);
 941     LOG_OFFSET(xtty, insts);
 942     LOG_OFFSET(xtty, stub);
 943     LOG_OFFSET(xtty, scopes_data);
 944     LOG_OFFSET(xtty, scopes_pcs);
 945     LOG_OFFSET(xtty, dependencies);
 946     LOG_OFFSET(xtty, handler_table);
 947     LOG_OFFSET(xtty, nul_chk_table);
 948     LOG_OFFSET(xtty, oops);
 949 
 950     xtty->method(method());
 951     xtty->stamp();
 952     xtty->end_elem();
 953   }
 954 }
 955 
 956 #undef LOG_OFFSET
 957 
 958 
 959 // Print out more verbose output usually for a newly created nmethod.
 960 void nmethod::print_on(outputStream* st, const char* msg) const {
 961   if (st != NULL) {
 962     ttyLocker ttyl;
 963     if (WizardMode) {
 964       CompileTask::print_compilation(st, this, msg, /*short_form:*/ true);
 965       st->print_cr(" (" INTPTR_FORMAT ")", this);
 966     } else {
 967       CompileTask::print_compilation(st, this, msg, /*short_form:*/ false);
 968     }
 969   }
 970 }
 971 
 972 
 973 void nmethod::print_nmethod(bool printmethod) {
 974   ttyLocker ttyl;  // keep the following output all in one block
 975   if (xtty != NULL) {
 976     xtty->begin_head("print_nmethod");
 977     xtty->stamp();
 978     xtty->end_head();
 979   }
 980   // print the header part first
 981   print();
 982   // then print the requested information
 983   if (printmethod) {
 984     print_code();
 985     print_pcs();
 986     if (oop_maps()) {
 987       oop_maps()->print();
 988     }
 989   }
 990   if (PrintDebugInfo) {
 991     print_scopes();
 992   }
 993   if (PrintRelocations) {
 994     print_relocations();
 995   }
 996   if (PrintDependencies) {
 997     print_dependencies();
 998   }
 999   if (PrintExceptionHandlers) {
1000     print_handler_table();
1001     print_nul_chk_table();
1002   }
1003   if (xtty != NULL) {
1004     xtty->tail("print_nmethod");
1005   }
1006 }
1007 
1008 
1009 // Promote one word from an assembly-time handle to a live embedded oop.
1010 inline void nmethod::initialize_immediate_oop(oop* dest, jobject handle) {
1011   if (handle == NULL ||
1012       // As a special case, IC oops are initialized to 1 or -1.
1013       handle == (jobject) Universe::non_oop_word()) {
1014     (*dest) = (oop) handle;
1015   } else {
1016     (*dest) = JNIHandles::resolve_non_null(handle);
1017   }
1018 }
1019 
1020 
1021 // Have to have the same name because it's called by a template
1022 void nmethod::copy_values(GrowableArray<jobject>* array) {
1023   int length = array->length();
1024   assert((address)(oops_begin() + length) <= (address)oops_end(), "oops big enough");
1025   oop* dest = oops_begin();
1026   for (int index = 0 ; index < length; index++) {
1027     initialize_immediate_oop(&dest[index], array->at(index));
1028   }
1029 
1030   // Now we can fix up all the oops in the code.  We need to do this
1031   // in the code because the assembler uses jobjects as placeholders.
1032   // The code and relocations have already been initialized by the
1033   // CodeBlob constructor, so it is valid even at this early point to
1034   // iterate over relocations and patch the code.
1035   fix_oop_relocations(NULL, NULL, /*initialize_immediates=*/ true);
1036 }
1037 
1038 void nmethod::copy_values(GrowableArray<Metadata*>* array) {
1039   int length = array->length();
1040   assert((address)(metadata_begin() + length) <= (address)metadata_end(), "big enough");
1041   Metadata** dest = metadata_begin();
1042   for (int index = 0 ; index < length; index++) {
1043     dest[index] = array->at(index);
1044   }
1045 }
1046 
1047 bool nmethod::is_at_poll_return(address pc) {
1048   RelocIterator iter(this, pc, pc+1);
1049   while (iter.next()) {
1050     if (iter.type() == relocInfo::poll_return_type)
1051       return true;
1052   }
1053   return false;
1054 }
1055 
1056 
1057 bool nmethod::is_at_poll_or_poll_return(address pc) {
1058   RelocIterator iter(this, pc, pc+1);
1059   while (iter.next()) {
1060     relocInfo::relocType t = iter.type();
1061     if (t == relocInfo::poll_return_type || t == relocInfo::poll_type)
1062       return true;
1063   }
1064   return false;
1065 }
1066 
1067 
1068 void nmethod::fix_oop_relocations(address begin, address end, bool initialize_immediates) {
1069   // re-patch all oop-bearing instructions, just in case some oops moved
1070   RelocIterator iter(this, begin, end);
1071   while (iter.next()) {
1072     if (iter.type() == relocInfo::oop_type) {
1073       oop_Relocation* reloc = iter.oop_reloc();
1074       if (initialize_immediates && reloc->oop_is_immediate()) {
1075         oop* dest = reloc->oop_addr();
1076         initialize_immediate_oop(dest, (jobject) *dest);
1077       }
1078       // Refresh the oop-related bits of this instruction.
1079       reloc->fix_oop_relocation();
1080     } else if (iter.type() == relocInfo::metadata_type) {
1081       metadata_Relocation* reloc = iter.metadata_reloc();
1082       reloc->fix_metadata_relocation();
1083     }
1084 
1085     // There must not be any interfering patches or breakpoints.
1086     assert(!(iter.type() == relocInfo::breakpoint_type
1087              && iter.breakpoint_reloc()->active()),
1088            "no active breakpoint");
1089   }
1090 }
1091 
1092 
1093 void nmethod::verify_oop_relocations() {
1094   // Ensure sure that the code matches the current oop values
1095   RelocIterator iter(this, NULL, NULL);
1096   while (iter.next()) {
1097     if (iter.type() == relocInfo::oop_type) {
1098       oop_Relocation* reloc = iter.oop_reloc();
1099       if (!reloc->oop_is_immediate()) {
1100         reloc->verify_oop_relocation();
1101       }
1102     }
1103   }
1104 }
1105 
1106 
1107 ScopeDesc* nmethod::scope_desc_at(address pc) {
1108   PcDesc* pd = pc_desc_at(pc);
1109   guarantee(pd != NULL, "scope must be present");
1110   return new ScopeDesc(this, pd->scope_decode_offset(),
1111                        pd->obj_decode_offset(), pd->should_reexecute(),
1112                        pd->return_oop());
1113 }
1114 
1115 
1116 void nmethod::clear_inline_caches() {
1117   assert(SafepointSynchronize::is_at_safepoint(), "cleaning of IC's only allowed at safepoint");
1118   if (is_zombie()) {
1119     return;
1120   }
1121 
1122   RelocIterator iter(this);
1123   while (iter.next()) {
1124     iter.reloc()->clear_inline_cache();
1125   }
1126 }
1127 
1128 
1129 void nmethod::cleanup_inline_caches() {
1130 
1131   assert_locked_or_safepoint(CompiledIC_lock);
1132 
1133   // If the method is not entrant or zombie then a JMP is plastered over the
1134   // first few bytes.  If an oop in the old code was there, that oop
1135   // should not get GC'd.  Skip the first few bytes of oops on
1136   // not-entrant methods.
1137   address low_boundary = verified_entry_point();
1138   if (!is_in_use()) {
1139     low_boundary += NativeJump::instruction_size;
1140     // %%% Note:  On SPARC we patch only a 4-byte trap, not a full NativeJump.
1141     // This means that the low_boundary is going to be a little too high.
1142     // This shouldn't matter, since oops of non-entrant methods are never used.
1143     // In fact, why are we bothering to look at oops in a non-entrant method??
1144   }
1145 
1146   // Find all calls in an nmethod, and clear the ones that points to zombie methods
1147   ResourceMark rm;
1148   RelocIterator iter(this, low_boundary);
1149   while(iter.next()) {
1150     switch(iter.type()) {
1151       case relocInfo::virtual_call_type:
1152       case relocInfo::opt_virtual_call_type: {
1153         CompiledIC *ic = CompiledIC_at(iter.reloc());
1154         // Ok, to lookup references to zombies here
1155         CodeBlob *cb = CodeCache::find_blob_unsafe(ic->ic_destination());
1156         if( cb != NULL && cb->is_nmethod() ) {
1157           nmethod* nm = (nmethod*)cb;
1158           // Clean inline caches pointing to both zombie and not_entrant methods
1159           if (!nm->is_in_use() || (nm->method()->code() != nm)) ic->set_to_clean();
1160         }
1161         break;
1162       }
1163       case relocInfo::static_call_type: {
1164         CompiledStaticCall *csc = compiledStaticCall_at(iter.reloc());
1165         CodeBlob *cb = CodeCache::find_blob_unsafe(csc->destination());
1166         if( cb != NULL && cb->is_nmethod() ) {
1167           nmethod* nm = (nmethod*)cb;
1168           // Clean inline caches pointing to both zombie and not_entrant methods
1169           if (!nm->is_in_use() || (nm->method()->code() != nm)) csc->set_to_clean();
1170         }
1171         break;
1172       }
1173     }
1174   }
1175 }
1176 
1177 // This is a private interface with the sweeper.
1178 void nmethod::mark_as_seen_on_stack() {
1179   assert(is_not_entrant(), "must be a non-entrant method");
1180   // Set the traversal mark to ensure that the sweeper does 2
1181   // cleaning passes before moving to zombie.
1182   set_stack_traversal_mark(NMethodSweeper::traversal_count());
1183 }
1184 
1185 // Tell if a non-entrant method can be converted to a zombie (i.e.,
1186 // there are no activations on the stack, not in use by the VM,
1187 // and not in use by the ServiceThread)
1188 bool nmethod::can_not_entrant_be_converted() {
1189   assert(is_not_entrant(), "must be a non-entrant method");
1190 
1191   // Since the nmethod sweeper only does partial sweep the sweeper's traversal
1192   // count can be greater than the stack traversal count before it hits the
1193   // nmethod for the second time.
1194   return stack_traversal_mark()+1 < NMethodSweeper::traversal_count() &&
1195          !is_locked_by_vm();
1196 }
1197 
1198 void nmethod::inc_decompile_count() {
1199   if (!is_compiled_by_c2()) return;
1200   // Could be gated by ProfileTraps, but do not bother...
1201   Method* m = method();
1202   if (m == NULL)  return;
1203   MethodData* mdo = m->method_data();
1204   if (mdo == NULL)  return;
1205   // There is a benign race here.  See comments in methodData.hpp.
1206   mdo->inc_decompile_count();
1207 }
1208 
1209 void nmethod::make_unloaded(BoolObjectClosure* is_alive, oop cause) {
1210 
1211   post_compiled_method_unload();
1212 
1213   // Since this nmethod is being unloaded, make sure that dependencies
1214   // recorded in instanceKlasses get flushed and pass non-NULL closure to
1215   // indicate that this work is being done during a GC.
1216   assert(Universe::heap()->is_gc_active(), "should only be called during gc");
1217   assert(is_alive != NULL, "Should be non-NULL");
1218   // A non-NULL is_alive closure indicates that this is being called during GC.
1219   flush_dependencies(is_alive);
1220 
1221   // Break cycle between nmethod & method
1222   if (TraceClassUnloading && WizardMode) {
1223     tty->print_cr("[Class unloading: Making nmethod " INTPTR_FORMAT
1224                   " unloadable], Method*(" INTPTR_FORMAT
1225                   "), cause(" INTPTR_FORMAT ")",
1226                   this, (address)_method, (address)cause);
1227     if (!Universe::heap()->is_gc_active())
1228       cause->klass()->print();
1229   }
1230   // Unlink the osr method, so we do not look this up again
1231   if (is_osr_method()) {
1232     invalidate_osr_method();
1233   }
1234   // If _method is already NULL the Method* is about to be unloaded,
1235   // so we don't have to break the cycle. Note that it is possible to
1236   // have the Method* live here, in case we unload the nmethod because
1237   // it is pointing to some oop (other than the Method*) being unloaded.
1238   if (_method != NULL) {
1239     // OSR methods point to the Method*, but the Method* does not
1240     // point back!
1241     if (_method->code() == this) {
1242       _method->clear_code(); // Break a cycle
1243     }
1244     _method = NULL;            // Clear the method of this dead nmethod
1245   }
1246   // Make the class unloaded - i.e., change state and notify sweeper
1247   assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
1248   if (is_in_use()) {
1249     // Transitioning directly from live to unloaded -- so
1250     // we need to force a cache clean-up; remember this
1251     // for later on.
1252     CodeCache::set_needs_cache_clean(true);
1253   }
1254   _state = unloaded;
1255 
1256   // Log the unloading.
1257   log_state_change();
1258 
1259   // The Method* is gone at this point
1260   assert(_method == NULL, "Tautology");
1261 
1262   set_osr_link(NULL);
1263   //set_scavenge_root_link(NULL); // done by prune_scavenge_root_nmethods
1264   NMethodSweeper::notify(this);
1265 }
1266 
1267 void nmethod::invalidate_osr_method() {
1268   assert(_entry_bci != InvocationEntryBci, "wrong kind of nmethod");
1269   // Remove from list of active nmethods
1270   if (method() != NULL)
1271     method()->method_holder()->remove_osr_nmethod(this);
1272   // Set entry as invalid
1273   _entry_bci = InvalidOSREntryBci;
1274 }
1275 
1276 void nmethod::log_state_change() const {
1277   if (LogCompilation) {
1278     if (xtty != NULL) {
1279       ttyLocker ttyl;  // keep the following output all in one block
1280       if (_state == unloaded) {
1281         xtty->begin_elem("make_unloaded thread='" UINTX_FORMAT "'",
1282                          os::current_thread_id());
1283       } else {
1284         xtty->begin_elem("make_not_entrant thread='" UINTX_FORMAT "'%s",
1285                          os::current_thread_id(),
1286                          (_state == zombie ? " zombie='1'" : ""));
1287       }
1288       log_identity(xtty);
1289       xtty->stamp();
1290       xtty->end_elem();
1291     }
1292   }
1293   if (PrintCompilation && _state != unloaded) {
1294     print_on(tty, _state == zombie ? "made zombie" : "made not entrant");
1295   }
1296 }
1297 
1298 // Common functionality for both make_not_entrant and make_zombie
1299 bool nmethod::make_not_entrant_or_zombie(unsigned int state) {
1300   assert(state == zombie || state == not_entrant, "must be zombie or not_entrant");
1301   assert(!is_zombie(), "should not already be a zombie");
1302 
1303   // Make sure neither the nmethod nor the method is flushed in case of a safepoint in code below.
1304   nmethodLocker nml(this);
1305   methodHandle the_method(method());
1306   No_Safepoint_Verifier nsv;
1307 
1308   {
1309     // invalidate osr nmethod before acquiring the patching lock since
1310     // they both acquire leaf locks and we don't want a deadlock.
1311     // This logic is equivalent to the logic below for patching the
1312     // verified entry point of regular methods.
1313     if (is_osr_method()) {
1314       // this effectively makes the osr nmethod not entrant
1315       invalidate_osr_method();
1316     }
1317 
1318     // Enter critical section.  Does not block for safepoint.
1319     MutexLockerEx pl(Patching_lock, Mutex::_no_safepoint_check_flag);
1320 
1321     if (_state == state) {
1322       // another thread already performed this transition so nothing
1323       // to do, but return false to indicate this.
1324       return false;
1325     }
1326 
1327     // The caller can be calling the method statically or through an inline
1328     // cache call.
1329     if (!is_osr_method() && !is_not_entrant()) {
1330       NativeJump::patch_verified_entry(entry_point(), verified_entry_point(),
1331                   SharedRuntime::get_handle_wrong_method_stub());
1332     }
1333 
1334     if (is_in_use()) {
1335       // It's a true state change, so mark the method as decompiled.
1336       // Do it only for transition from alive.
1337       inc_decompile_count();
1338     }
1339 
1340     // Change state
1341     _state = state;
1342 
1343     // Log the transition once
1344     log_state_change();
1345 
1346     // Remove nmethod from method.
1347     // We need to check if both the _code and _from_compiled_code_entry_point
1348     // refer to this nmethod because there is a race in setting these two fields
1349     // in Method* as seen in bugid 4947125.
1350     // If the vep() points to the zombie nmethod, the memory for the nmethod
1351     // could be flushed and the compiler and vtable stubs could still call
1352     // through it.
1353     if (method() != NULL && (method()->code() == this ||
1354                              method()->from_compiled_entry() == verified_entry_point())) {
1355       HandleMark hm;
1356       method()->clear_code();
1357     }
1358 
1359     if (state == not_entrant) {
1360       mark_as_seen_on_stack();
1361     }
1362 
1363   } // leave critical region under Patching_lock
1364 
1365   // When the nmethod becomes zombie it is no longer alive so the
1366   // dependencies must be flushed.  nmethods in the not_entrant
1367   // state will be flushed later when the transition to zombie
1368   // happens or they get unloaded.
1369   if (state == zombie) {
1370     {
1371       // Flushing dependecies must be done before any possible
1372       // safepoint can sneak in, otherwise the oops used by the
1373       // dependency logic could have become stale.
1374       MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
1375       flush_dependencies(NULL);
1376     }
1377 
1378     // zombie only - if a JVMTI agent has enabled the CompiledMethodUnload
1379     // event and it hasn't already been reported for this nmethod then
1380     // report it now. The event may have been reported earilier if the GC
1381     // marked it for unloading). JvmtiDeferredEventQueue support means
1382     // we no longer go to a safepoint here.
1383     post_compiled_method_unload();
1384 
1385 #ifdef ASSERT
1386     // It's no longer safe to access the oops section since zombie
1387     // nmethods aren't scanned for GC.
1388     _oops_are_stale = true;
1389 #endif
1390   } else {
1391     assert(state == not_entrant, "other cases may need to be handled differently");
1392   }
1393 
1394   if (TraceCreateZombies) {
1395     tty->print_cr("nmethod <" INTPTR_FORMAT "> code made %s", this, (state == not_entrant) ? "not entrant" : "zombie");
1396   }
1397 
1398   // Make sweeper aware that there is a zombie method that needs to be removed
1399   NMethodSweeper::notify(this);
1400 
1401   return true;
1402 }
1403 
1404 void nmethod::flush() {
1405   // Note that there are no valid oops in the nmethod anymore.
1406   assert(is_zombie() || (is_osr_method() && is_unloaded()), "must be a zombie method");
1407   assert(is_marked_for_reclamation() || (is_osr_method() && is_unloaded()), "must be marked for reclamation");
1408 
1409   assert (!is_locked_by_vm(), "locked methods shouldn't be flushed");
1410   assert_locked_or_safepoint(CodeCache_lock);
1411 
1412   // completely deallocate this method
1413   Events::log(JavaThread::current(), "flushing nmethod " INTPTR_FORMAT, this);
1414   if (PrintMethodFlushing) {
1415     tty->print_cr("*flushing nmethod %3d/" INTPTR_FORMAT ". Live blobs:" UINT32_FORMAT "/Free CodeCache:" SIZE_FORMAT "Kb",
1416         _compile_id, this, CodeCache::nof_blobs(), CodeCache::unallocated_capacity()/1024);
1417   }
1418 
1419   // We need to deallocate any ExceptionCache data.
1420   // Note that we do not need to grab the nmethod lock for this, it
1421   // better be thread safe if we're disposing of it!
1422   ExceptionCache* ec = exception_cache();
1423   set_exception_cache(NULL);
1424   while(ec != NULL) {
1425     ExceptionCache* next = ec->next();
1426     delete ec;
1427     ec = next;
1428   }
1429 
1430   if (on_scavenge_root_list()) {
1431     CodeCache::drop_scavenge_root_nmethod(this);
1432   }
1433 
1434   if (is_speculatively_disconnected()) {
1435     CodeCache::remove_saved_code(this);
1436   }
1437 
1438 #ifdef SHARK
1439   ((SharkCompiler *) compiler())->free_compiled_method(insts_begin());
1440 #endif // SHARK
1441 
1442   ((CodeBlob*)(this))->flush();
1443 
1444   CodeCache::free(this);
1445 }
1446 
1447 
1448 //
1449 // Notify all classes this nmethod is dependent on that it is no
1450 // longer dependent. This should only be called in two situations.
1451 // First, when a nmethod transitions to a zombie all dependents need
1452 // to be clear.  Since zombification happens at a safepoint there's no
1453 // synchronization issues.  The second place is a little more tricky.
1454 // During phase 1 of mark sweep class unloading may happen and as a
1455 // result some nmethods may get unloaded.  In this case the flushing
1456 // of dependencies must happen during phase 1 since after GC any
1457 // dependencies in the unloaded nmethod won't be updated, so
1458 // traversing the dependency information in unsafe.  In that case this
1459 // function is called with a non-NULL argument and this function only
1460 // notifies instanceKlasses that are reachable
1461 
1462 void nmethod::flush_dependencies(BoolObjectClosure* is_alive) {
1463   assert_locked_or_safepoint(CodeCache_lock);
1464   assert(Universe::heap()->is_gc_active() == (is_alive != NULL),
1465   "is_alive is non-NULL if and only if we are called during GC");
1466   if (!has_flushed_dependencies()) {
1467     set_has_flushed_dependencies();
1468     for (Dependencies::DepStream deps(this); deps.next(); ) {
1469       Klass* klass = deps.context_type();
1470       if (klass == NULL)  continue;  // ignore things like evol_method
1471 
1472       // During GC the is_alive closure is non-NULL, and is used to
1473       // determine liveness of dependees that need to be updated.
1474       if (is_alive == NULL || klass->is_loader_alive(is_alive)) {
1475         InstanceKlass::cast(klass)->remove_dependent_nmethod(this);
1476       }
1477     }
1478   }
1479 }
1480 
1481 
1482 // If this oop is not live, the nmethod can be unloaded.
1483 bool nmethod::can_unload(BoolObjectClosure* is_alive, oop* root, bool unloading_occurred) {
1484   assert(root != NULL, "just checking");
1485   oop obj = *root;
1486   if (obj == NULL || is_alive->do_object_b(obj)) {
1487       return false;
1488   }
1489 
1490   // If ScavengeRootsInCode is true, an nmethod might be unloaded
1491   // simply because one of its constant oops has gone dead.
1492   // No actual classes need to be unloaded in order for this to occur.
1493   assert(unloading_occurred || ScavengeRootsInCode, "Inconsistency in unloading");
1494   make_unloaded(is_alive, obj);
1495   return true;
1496 }
1497 
1498 // ------------------------------------------------------------------
1499 // post_compiled_method_load_event
1500 // new method for install_code() path
1501 // Transfer information from compilation to jvmti
1502 void nmethod::post_compiled_method_load_event() {
1503 
1504   Method* moop = method();
1505 #ifndef USDT2
1506   HS_DTRACE_PROBE8(hotspot, compiled__method__load,
1507       moop->klass_name()->bytes(),
1508       moop->klass_name()->utf8_length(),
1509       moop->name()->bytes(),
1510       moop->name()->utf8_length(),
1511       moop->signature()->bytes(),
1512       moop->signature()->utf8_length(),
1513       insts_begin(), insts_size());
1514 #else /* USDT2 */
1515   HOTSPOT_COMPILED_METHOD_LOAD(
1516       (char *) moop->klass_name()->bytes(),
1517       moop->klass_name()->utf8_length(),
1518       (char *) moop->name()->bytes(),
1519       moop->name()->utf8_length(),
1520       (char *) moop->signature()->bytes(),
1521       moop->signature()->utf8_length(),
1522       insts_begin(), insts_size());
1523 #endif /* USDT2 */
1524 
1525   if (JvmtiExport::should_post_compiled_method_load() ||
1526       JvmtiExport::should_post_compiled_method_unload()) {
1527     get_and_cache_jmethod_id();
1528   }
1529 
1530   if (JvmtiExport::should_post_compiled_method_load()) {
1531     // Let the Service thread (which is a real Java thread) post the event
1532     MutexLockerEx ml(Service_lock, Mutex::_no_safepoint_check_flag);
1533     JvmtiDeferredEventQueue::enqueue(
1534       JvmtiDeferredEvent::compiled_method_load_event(this));
1535   }
1536 }
1537 
1538 jmethodID nmethod::get_and_cache_jmethod_id() {
1539   if (_jmethod_id == NULL) {
1540     // Cache the jmethod_id since it can no longer be looked up once the
1541     // method itself has been marked for unloading.
1542     _jmethod_id = method()->jmethod_id();
1543   }
1544   return _jmethod_id;
1545 }
1546 
1547 void nmethod::post_compiled_method_unload() {
1548   if (unload_reported()) {
1549     // During unloading we transition to unloaded and then to zombie
1550     // and the unloading is reported during the first transition.
1551     return;
1552   }
1553 
1554   assert(_method != NULL && !is_unloaded(), "just checking");
1555   DTRACE_METHOD_UNLOAD_PROBE(method());
1556 
1557   // If a JVMTI agent has enabled the CompiledMethodUnload event then
1558   // post the event. Sometime later this nmethod will be made a zombie
1559   // by the sweeper but the Method* will not be valid at that point.
1560   // If the _jmethod_id is null then no load event was ever requested
1561   // so don't bother posting the unload.  The main reason for this is
1562   // that the jmethodID is a weak reference to the Method* so if
1563   // it's being unloaded there's no way to look it up since the weak
1564   // ref will have been cleared.
1565   if (_jmethod_id != NULL && JvmtiExport::should_post_compiled_method_unload()) {
1566     assert(!unload_reported(), "already unloaded");
1567     JvmtiDeferredEvent event =
1568       JvmtiDeferredEvent::compiled_method_unload_event(this,
1569           _jmethod_id, insts_begin());
1570     if (SafepointSynchronize::is_at_safepoint()) {
1571       // Don't want to take the queueing lock. Add it as pending and
1572       // it will get enqueued later.
1573       JvmtiDeferredEventQueue::add_pending_event(event);
1574     } else {
1575       MutexLockerEx ml(Service_lock, Mutex::_no_safepoint_check_flag);
1576       JvmtiDeferredEventQueue::enqueue(event);
1577     }
1578   }
1579 
1580   // The JVMTI CompiledMethodUnload event can be enabled or disabled at
1581   // any time. As the nmethod is being unloaded now we mark it has
1582   // having the unload event reported - this will ensure that we don't
1583   // attempt to report the event in the unlikely scenario where the
1584   // event is enabled at the time the nmethod is made a zombie.
1585   set_unload_reported();
1586 }
1587 
1588 // This is called at the end of the strong tracing/marking phase of a
1589 // GC to unload an nmethod if it contains otherwise unreachable
1590 // oops.
1591 
1592 void nmethod::do_unloading(BoolObjectClosure* is_alive, bool unloading_occurred) {
1593   // Make sure the oop's ready to receive visitors
1594   assert(!is_zombie() && !is_unloaded(),
1595          "should not call follow on zombie or unloaded nmethod");
1596 
1597   // If the method is not entrant then a JMP is plastered over the
1598   // first few bytes.  If an oop in the old code was there, that oop
1599   // should not get GC'd.  Skip the first few bytes of oops on
1600   // not-entrant methods.
1601   address low_boundary = verified_entry_point();
1602   if (is_not_entrant()) {
1603     low_boundary += NativeJump::instruction_size;
1604     // %%% Note:  On SPARC we patch only a 4-byte trap, not a full NativeJump.
1605     // (See comment above.)
1606   }
1607 
1608   // The RedefineClasses() API can cause the class unloading invariant
1609   // to no longer be true. See jvmtiExport.hpp for details.
1610   // Also, leave a debugging breadcrumb in local flag.
1611   bool a_class_was_redefined = JvmtiExport::has_redefined_a_class();
1612   if (a_class_was_redefined) {
1613     // This set of the unloading_occurred flag is done before the
1614     // call to post_compiled_method_unload() so that the unloading
1615     // of this nmethod is reported.
1616     unloading_occurred = true;
1617   }
1618 
1619   // Exception cache
1620   ExceptionCache* ec = exception_cache();
1621   while (ec != NULL) {
1622     Klass* ex_klass = ec->exception_type();
1623     ExceptionCache* next_ec = ec->next();
1624     if (ex_klass != NULL && !ex_klass->is_loader_alive(is_alive)) {
1625       remove_from_exception_cache(ec);
1626     }
1627     ec = next_ec;
1628   }
1629 
1630   // If class unloading occurred we first iterate over all inline caches and
1631   // clear ICs where the cached oop is referring to an unloaded klass or method.
1632   // The remaining live cached oops will be traversed in the relocInfo::oop_type
1633   // iteration below.
1634   if (unloading_occurred) {
1635     RelocIterator iter(this, low_boundary);
1636     while(iter.next()) {
1637       if (iter.type() == relocInfo::virtual_call_type) {
1638         CompiledIC *ic = CompiledIC_at(iter.reloc());
1639         if (ic->is_icholder_call()) {
1640           // The only exception is compiledICHolder oops which may
1641           // yet be marked below. (We check this further below).
1642           CompiledICHolder* cichk_oop = ic->cached_icholder();
1643           if (cichk_oop->holder_method()->method_holder()->is_loader_alive(is_alive) &&
1644               cichk_oop->holder_klass()->is_loader_alive(is_alive)) {
1645               continue;
1646             }
1647         } else {
1648           Metadata* ic_oop = ic->cached_metadata();
1649           if (ic_oop != NULL) {
1650             if (ic_oop->is_klass()) {
1651               if (((Klass*)ic_oop)->is_loader_alive(is_alive)) {
1652                 continue;
1653               }
1654             } else if (ic_oop->is_method()) {
1655               if (((Method*)ic_oop)->method_holder()->is_loader_alive(is_alive)) {
1656                 continue;
1657               }
1658             } else {
1659               ShouldNotReachHere();
1660             }
1661           }
1662           }
1663           ic->set_to_clean();
1664       }
1665     }
1666   }
1667 
1668   // Compiled code
1669   {
1670   RelocIterator iter(this, low_boundary);
1671   while (iter.next()) {
1672     if (iter.type() == relocInfo::oop_type) {
1673       oop_Relocation* r = iter.oop_reloc();
1674       // In this loop, we must only traverse those oops directly embedded in
1675       // the code.  Other oops (oop_index>0) are seen as part of scopes_oops.
1676       assert(1 == (r->oop_is_immediate()) +
1677                   (r->oop_addr() >= oops_begin() && r->oop_addr() < oops_end()),
1678              "oop must be found in exactly one place");
1679       if (r->oop_is_immediate() && r->oop_value() != NULL) {
1680         if (can_unload(is_alive, r->oop_addr(), unloading_occurred)) {
1681           return;
1682         }
1683       }
1684     }
1685   }
1686   }
1687 
1688 
1689   // Scopes
1690   for (oop* p = oops_begin(); p < oops_end(); p++) {
1691     if (*p == Universe::non_oop_word())  continue;  // skip non-oops
1692     if (can_unload(is_alive, p, unloading_occurred)) {
1693       return;
1694     }
1695   }
1696 
1697   // Ensure that all metadata is still alive
1698   verify_metadata_loaders(low_boundary, is_alive);
1699 }
1700 
1701 #ifdef ASSERT
1702 
1703 class CheckClass : AllStatic {
1704   static BoolObjectClosure* _is_alive;
1705 
1706   // Check class_loader is alive for this bit of metadata.
1707   static void check_class(Metadata* md) {
1708     Klass* klass = NULL;
1709     if (md->is_klass()) {
1710       klass = ((Klass*)md);
1711     } else if (md->is_method()) {
1712       klass = ((Method*)md)->method_holder();
1713     } else if (md->is_methodData()) {
1714       klass = ((MethodData*)md)->method()->method_holder();
1715     } else {
1716       md->print();
1717       ShouldNotReachHere();
1718     }
1719     assert(klass->is_loader_alive(_is_alive), "must be alive");
1720   }
1721  public:
1722   static void do_check_class(BoolObjectClosure* is_alive, nmethod* nm) {
1723     assert(SafepointSynchronize::is_at_safepoint(), "this is only ok at safepoint");
1724     _is_alive = is_alive;
1725     nm->metadata_do(check_class);
1726   }
1727 };
1728 
1729 // This is called during a safepoint so can use static data
1730 BoolObjectClosure* CheckClass::_is_alive = NULL;
1731 #endif // ASSERT
1732 
1733 
1734 // Processing of oop references should have been sufficient to keep
1735 // all strong references alive.  Any weak references should have been
1736 // cleared as well.  Visit all the metadata and ensure that it's
1737 // really alive.
1738 void nmethod::verify_metadata_loaders(address low_boundary, BoolObjectClosure* is_alive) {
1739 #ifdef ASSERT
1740     RelocIterator iter(this, low_boundary);
1741     while (iter.next()) {
1742     // static_stub_Relocations may have dangling references to
1743     // Method*s so trim them out here.  Otherwise it looks like
1744     // compiled code is maintaining a link to dead metadata.
1745     address static_call_addr = NULL;
1746     if (iter.type() == relocInfo::opt_virtual_call_type) {
1747       CompiledIC* cic = CompiledIC_at(iter.reloc());
1748       if (!cic->is_call_to_interpreted()) {
1749         static_call_addr = iter.addr();
1750       }
1751     } else if (iter.type() == relocInfo::static_call_type) {
1752       CompiledStaticCall* csc = compiledStaticCall_at(iter.reloc());
1753       if (!csc->is_call_to_interpreted()) {
1754         static_call_addr = iter.addr();
1755       }
1756     }
1757     if (static_call_addr != NULL) {
1758       RelocIterator sciter(this, low_boundary);
1759       while (sciter.next()) {
1760         if (sciter.type() == relocInfo::static_stub_type &&
1761             sciter.static_stub_reloc()->static_call() == static_call_addr) {
1762           sciter.static_stub_reloc()->clear_inline_cache();
1763         }
1764       }
1765     }
1766   }
1767   // Check that the metadata embedded in the nmethod is alive
1768   CheckClass::do_check_class(is_alive, this);
1769 #endif
1770 }
1771 
1772 
1773 // Iterate over metadata calling this function.   Used by RedefineClasses
1774 void nmethod::metadata_do(void f(Metadata*)) {
1775   address low_boundary = verified_entry_point();
1776   if (is_not_entrant()) {
1777     low_boundary += NativeJump::instruction_size;
1778     // %%% Note:  On SPARC we patch only a 4-byte trap, not a full NativeJump.
1779     // (See comment above.)
1780   }
1781   {
1782     // Visit all immediate references that are embedded in the instruction stream.
1783     RelocIterator iter(this, low_boundary);
1784     while (iter.next()) {
1785       if (iter.type() == relocInfo::metadata_type ) {
1786         metadata_Relocation* r = iter.metadata_reloc();
1787         // In this lmetadata, we must only follow those metadatas directly embedded in
1788         // the code.  Other metadatas (oop_index>0) are seen as part of
1789         // the metadata section below.
1790         assert(1 == (r->metadata_is_immediate()) +
1791                (r->metadata_addr() >= metadata_begin() && r->metadata_addr() < metadata_end()),
1792                "metadata must be found in exactly one place");
1793         if (r->metadata_is_immediate() && r->metadata_value() != NULL) {
1794           Metadata* md = r->metadata_value();
1795           f(md);
1796         }
1797       } else if (iter.type() == relocInfo::virtual_call_type) {
1798         // Check compiledIC holders associated with this nmethod
1799         CompiledIC *ic = CompiledIC_at(iter.reloc());
1800         if (ic->is_icholder_call()) {
1801           CompiledICHolder* cichk = ic->cached_icholder();
1802           f(cichk->holder_method());
1803           f(cichk->holder_klass());
1804         } else {
1805           Metadata* ic_oop = ic->cached_metadata();
1806           if (ic_oop != NULL) {
1807             f(ic_oop);
1808           }
1809         }
1810       }
1811     }
1812   }
1813 
1814   // Visit the metadata section
1815   for (Metadata** p = metadata_begin(); p < metadata_end(); p++) {
1816     if (*p == Universe::non_oop_word() || *p == NULL)  continue;  // skip non-oops
1817     Metadata* md = *p;
1818     f(md);
1819   }
1820 
1821   // Call function Method*, not embedded in these other places.
1822   if (_method != NULL) f(_method);
1823 }
1824 
1825 
1826 // This method is called twice during GC -- once while
1827 // tracing the "active" nmethods on thread stacks during
1828 // the (strong) marking phase, and then again when walking
1829 // the code cache contents during the weak roots processing
1830 // phase. The two uses are distinguished by means of the
1831 // 'do_strong_roots_only' flag, which is true in the first
1832 // case. We want to walk the weak roots in the nmethod
1833 // only in the second case. The weak roots in the nmethod
1834 // are the oops in the ExceptionCache and the InlineCache
1835 // oops.
1836 void nmethod::oops_do(OopClosure* f, bool do_strong_roots_only) {
1837   // make sure the oops ready to receive visitors
1838   assert(!is_zombie() && !is_unloaded(),
1839          "should not call follow on zombie or unloaded nmethod");
1840 
1841   // If the method is not entrant or zombie then a JMP is plastered over the
1842   // first few bytes.  If an oop in the old code was there, that oop
1843   // should not get GC'd.  Skip the first few bytes of oops on
1844   // not-entrant methods.
1845   address low_boundary = verified_entry_point();
1846   if (is_not_entrant()) {
1847     low_boundary += NativeJump::instruction_size;
1848     // %%% Note:  On SPARC we patch only a 4-byte trap, not a full NativeJump.
1849     // (See comment above.)
1850   }
1851 
1852   RelocIterator iter(this, low_boundary);
1853 
1854   while (iter.next()) {
1855     if (iter.type() == relocInfo::oop_type ) {
1856       oop_Relocation* r = iter.oop_reloc();
1857       // In this loop, we must only follow those oops directly embedded in
1858       // the code.  Other oops (oop_index>0) are seen as part of scopes_oops.
1859       assert(1 == (r->oop_is_immediate()) +
1860                    (r->oop_addr() >= oops_begin() && r->oop_addr() < oops_end()),
1861              "oop must be found in exactly one place");
1862       if (r->oop_is_immediate() && r->oop_value() != NULL) {
1863         f->do_oop(r->oop_addr());
1864       }
1865     }
1866   }
1867 
1868   // Scopes
1869   // This includes oop constants not inlined in the code stream.
1870   for (oop* p = oops_begin(); p < oops_end(); p++) {
1871     if (*p == Universe::non_oop_word())  continue;  // skip non-oops
1872     f->do_oop(p);
1873   }
1874 }
1875 
1876 #define NMETHOD_SENTINEL ((nmethod*)badAddress)
1877 
1878 nmethod* volatile nmethod::_oops_do_mark_nmethods;
1879 
1880 // An nmethod is "marked" if its _mark_link is set non-null.
1881 // Even if it is the end of the linked list, it will have a non-null link value,
1882 // as long as it is on the list.
1883 // This code must be MP safe, because it is used from parallel GC passes.
1884 bool nmethod::test_set_oops_do_mark() {
1885   assert(nmethod::oops_do_marking_is_active(), "oops_do_marking_prologue must be called");
1886   nmethod* observed_mark_link = _oops_do_mark_link;
1887   if (observed_mark_link == NULL) {
1888     // Claim this nmethod for this thread to mark.
1889     observed_mark_link = (nmethod*)
1890       Atomic::cmpxchg_ptr(NMETHOD_SENTINEL, &_oops_do_mark_link, NULL);
1891     if (observed_mark_link == NULL) {
1892 
1893       // Atomically append this nmethod (now claimed) to the head of the list:
1894       nmethod* observed_mark_nmethods = _oops_do_mark_nmethods;
1895       for (;;) {
1896         nmethod* required_mark_nmethods = observed_mark_nmethods;
1897         _oops_do_mark_link = required_mark_nmethods;
1898         observed_mark_nmethods = (nmethod*)
1899           Atomic::cmpxchg_ptr(this, &_oops_do_mark_nmethods, required_mark_nmethods);
1900         if (observed_mark_nmethods == required_mark_nmethods)
1901           break;
1902       }
1903       // Mark was clear when we first saw this guy.
1904       NOT_PRODUCT(if (TraceScavenge)  print_on(tty, "oops_do, mark"));
1905       return false;
1906     }
1907   }
1908   // On fall through, another racing thread marked this nmethod before we did.
1909   return true;
1910 }
1911 
1912 void nmethod::oops_do_marking_prologue() {
1913   NOT_PRODUCT(if (TraceScavenge)  tty->print_cr("[oops_do_marking_prologue"));
1914   assert(_oops_do_mark_nmethods == NULL, "must not call oops_do_marking_prologue twice in a row");
1915   // We use cmpxchg_ptr instead of regular assignment here because the user
1916   // may fork a bunch of threads, and we need them all to see the same state.
1917   void* observed = Atomic::cmpxchg_ptr(NMETHOD_SENTINEL, &_oops_do_mark_nmethods, NULL);
1918   guarantee(observed == NULL, "no races in this sequential code");
1919 }
1920 
1921 void nmethod::oops_do_marking_epilogue() {
1922   assert(_oops_do_mark_nmethods != NULL, "must not call oops_do_marking_epilogue twice in a row");
1923   nmethod* cur = _oops_do_mark_nmethods;
1924   while (cur != NMETHOD_SENTINEL) {
1925     assert(cur != NULL, "not NULL-terminated");
1926     nmethod* next = cur->_oops_do_mark_link;
1927     cur->_oops_do_mark_link = NULL;
1928     cur->fix_oop_relocations();
1929     NOT_PRODUCT(if (TraceScavenge)  cur->print_on(tty, "oops_do, unmark"));
1930     cur = next;
1931   }
1932   void* required = _oops_do_mark_nmethods;
1933   void* observed = Atomic::cmpxchg_ptr(NULL, &_oops_do_mark_nmethods, required);
1934   guarantee(observed == required, "no races in this sequential code");
1935   NOT_PRODUCT(if (TraceScavenge)  tty->print_cr("oops_do_marking_epilogue]"));
1936 }
1937 
1938 class DetectScavengeRoot: public OopClosure {
1939   bool     _detected_scavenge_root;
1940 public:
1941   DetectScavengeRoot() : _detected_scavenge_root(false)
1942   { NOT_PRODUCT(_print_nm = NULL); }
1943   bool detected_scavenge_root() { return _detected_scavenge_root; }
1944   virtual void do_oop(oop* p) {
1945     if ((*p) != NULL && (*p)->is_scavengable()) {
1946       NOT_PRODUCT(maybe_print(p));
1947       _detected_scavenge_root = true;
1948     }
1949   }
1950   virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
1951 
1952 #ifndef PRODUCT
1953   nmethod* _print_nm;
1954   void maybe_print(oop* p) {
1955     if (_print_nm == NULL)  return;
1956     if (!_detected_scavenge_root)  _print_nm->print_on(tty, "new scavenge root");
1957     tty->print_cr(""PTR_FORMAT"[offset=%d] detected scavengable oop "PTR_FORMAT" (found at "PTR_FORMAT")",
1958                   _print_nm, (int)((intptr_t)p - (intptr_t)_print_nm),
1959                   (intptr_t)(*p), (intptr_t)p);
1960     (*p)->print();
1961   }
1962 #endif //PRODUCT
1963 };
1964 
1965 bool nmethod::detect_scavenge_root_oops() {
1966   DetectScavengeRoot detect_scavenge_root;
1967   NOT_PRODUCT(if (TraceScavenge)  detect_scavenge_root._print_nm = this);
1968   oops_do(&detect_scavenge_root);
1969   return detect_scavenge_root.detected_scavenge_root();
1970 }
1971 
1972 // Method that knows how to preserve outgoing arguments at call. This method must be
1973 // called with a frame corresponding to a Java invoke
1974 void nmethod::preserve_callee_argument_oops(frame fr, const RegisterMap *reg_map, OopClosure* f) {
1975 #ifndef SHARK
1976   if (!method()->is_native()) {
1977     SimpleScopeDesc ssd(this, fr.pc());
1978     Bytecode_invoke call(ssd.method(), ssd.bci());
1979     bool has_receiver = call.has_receiver();
1980     bool has_appendix = call.has_appendix();
1981     Symbol* signature = call.signature();
1982     fr.oops_compiled_arguments_do(signature, has_receiver, has_appendix, reg_map, f);
1983   }
1984 #endif // !SHARK
1985 }
1986 
1987 
1988 oop nmethod::embeddedOop_at(u_char* p) {
1989   RelocIterator iter(this, p, p + 1);
1990   while (iter.next())
1991     if (iter.type() == relocInfo::oop_type) {
1992       return iter.oop_reloc()->oop_value();
1993     }
1994   return NULL;
1995 }
1996 
1997 
1998 inline bool includes(void* p, void* from, void* to) {
1999   return from <= p && p < to;
2000 }
2001 
2002 
2003 void nmethod::copy_scopes_pcs(PcDesc* pcs, int count) {
2004   assert(count >= 2, "must be sentinel values, at least");
2005 
2006 #ifdef ASSERT
2007   // must be sorted and unique; we do a binary search in find_pc_desc()
2008   int prev_offset = pcs[0].pc_offset();
2009   assert(prev_offset == PcDesc::lower_offset_limit,
2010          "must start with a sentinel");
2011   for (int i = 1; i < count; i++) {
2012     int this_offset = pcs[i].pc_offset();
2013     assert(this_offset > prev_offset, "offsets must be sorted");
2014     prev_offset = this_offset;
2015   }
2016   assert(prev_offset == PcDesc::upper_offset_limit,
2017          "must end with a sentinel");
2018 #endif //ASSERT
2019 
2020   // Search for MethodHandle invokes and tag the nmethod.
2021   for (int i = 0; i < count; i++) {
2022     if (pcs[i].is_method_handle_invoke()) {
2023       set_has_method_handle_invokes(true);
2024       break;
2025     }
2026   }
2027   assert(has_method_handle_invokes() == (_deoptimize_mh_offset != -1), "must have deopt mh handler");
2028 
2029   int size = count * sizeof(PcDesc);
2030   assert(scopes_pcs_size() >= size, "oob");
2031   memcpy(scopes_pcs_begin(), pcs, size);
2032 
2033   // Adjust the final sentinel downward.
2034   PcDesc* last_pc = &scopes_pcs_begin()[count-1];
2035   assert(last_pc->pc_offset() == PcDesc::upper_offset_limit, "sanity");
2036   last_pc->set_pc_offset(content_size() + 1);
2037   for (; last_pc + 1 < scopes_pcs_end(); last_pc += 1) {
2038     // Fill any rounding gaps with copies of the last record.
2039     last_pc[1] = last_pc[0];
2040   }
2041   // The following assert could fail if sizeof(PcDesc) is not
2042   // an integral multiple of oopSize (the rounding term).
2043   // If it fails, change the logic to always allocate a multiple
2044   // of sizeof(PcDesc), and fill unused words with copies of *last_pc.
2045   assert(last_pc + 1 == scopes_pcs_end(), "must match exactly");
2046 }
2047 
2048 void nmethod::copy_scopes_data(u_char* buffer, int size) {
2049   assert(scopes_data_size() >= size, "oob");
2050   memcpy(scopes_data_begin(), buffer, size);
2051 }
2052 
2053 
2054 #ifdef ASSERT
2055 static PcDesc* linear_search(nmethod* nm, int pc_offset, bool approximate) {
2056   PcDesc* lower = nm->scopes_pcs_begin();
2057   PcDesc* upper = nm->scopes_pcs_end();
2058   lower += 1; // exclude initial sentinel
2059   PcDesc* res = NULL;
2060   for (PcDesc* p = lower; p < upper; p++) {
2061     NOT_PRODUCT(--nmethod_stats.pc_desc_tests);  // don't count this call to match_desc
2062     if (match_desc(p, pc_offset, approximate)) {
2063       if (res == NULL)
2064         res = p;
2065       else
2066         res = (PcDesc*) badAddress;
2067     }
2068   }
2069   return res;
2070 }
2071 #endif
2072 
2073 
2074 // Finds a PcDesc with real-pc equal to "pc"
2075 PcDesc* nmethod::find_pc_desc_internal(address pc, bool approximate) {
2076   address base_address = code_begin();
2077   if ((pc < base_address) ||
2078       (pc - base_address) >= (ptrdiff_t) PcDesc::upper_offset_limit) {
2079     return NULL;  // PC is wildly out of range
2080   }
2081   int pc_offset = (int) (pc - base_address);
2082 
2083   // Check the PcDesc cache if it contains the desired PcDesc
2084   // (This as an almost 100% hit rate.)
2085   PcDesc* res = _pc_desc_cache.find_pc_desc(pc_offset, approximate);
2086   if (res != NULL) {
2087     assert(res == linear_search(this, pc_offset, approximate), "cache ok");
2088     return res;
2089   }
2090 
2091   // Fallback algorithm: quasi-linear search for the PcDesc
2092   // Find the last pc_offset less than the given offset.
2093   // The successor must be the required match, if there is a match at all.
2094   // (Use a fixed radix to avoid expensive affine pointer arithmetic.)
2095   PcDesc* lower = scopes_pcs_begin();
2096   PcDesc* upper = scopes_pcs_end();
2097   upper -= 1; // exclude final sentinel
2098   if (lower >= upper)  return NULL;  // native method; no PcDescs at all
2099 
2100 #define assert_LU_OK \
2101   /* invariant on lower..upper during the following search: */ \
2102   assert(lower->pc_offset() <  pc_offset, "sanity"); \
2103   assert(upper->pc_offset() >= pc_offset, "sanity")
2104   assert_LU_OK;
2105 
2106   // Use the last successful return as a split point.
2107   PcDesc* mid = _pc_desc_cache.last_pc_desc();
2108   NOT_PRODUCT(++nmethod_stats.pc_desc_searches);
2109   if (mid->pc_offset() < pc_offset) {
2110     lower = mid;
2111   } else {
2112     upper = mid;
2113   }
2114 
2115   // Take giant steps at first (4096, then 256, then 16, then 1)
2116   const int LOG2_RADIX = 4 /*smaller steps in debug mode:*/ debug_only(-1);
2117   const int RADIX = (1 << LOG2_RADIX);
2118   for (int step = (1 << (LOG2_RADIX*3)); step > 1; step >>= LOG2_RADIX) {
2119     while ((mid = lower + step) < upper) {
2120       assert_LU_OK;
2121       NOT_PRODUCT(++nmethod_stats.pc_desc_searches);
2122       if (mid->pc_offset() < pc_offset) {
2123         lower = mid;
2124       } else {
2125         upper = mid;
2126         break;
2127       }
2128     }
2129     assert_LU_OK;
2130   }
2131 
2132   // Sneak up on the value with a linear search of length ~16.
2133   while (true) {
2134     assert_LU_OK;
2135     mid = lower + 1;
2136     NOT_PRODUCT(++nmethod_stats.pc_desc_searches);
2137     if (mid->pc_offset() < pc_offset) {
2138       lower = mid;
2139     } else {
2140       upper = mid;
2141       break;
2142     }
2143   }
2144 #undef assert_LU_OK
2145 
2146   if (match_desc(upper, pc_offset, approximate)) {
2147     assert(upper == linear_search(this, pc_offset, approximate), "search ok");
2148     _pc_desc_cache.add_pc_desc(upper);
2149     return upper;
2150   } else {
2151     assert(NULL == linear_search(this, pc_offset, approximate), "search ok");
2152     return NULL;
2153   }
2154 }
2155 
2156 
2157 bool nmethod::check_all_dependencies() {
2158   bool found_check = false;
2159   // wholesale check of all dependencies
2160   for (Dependencies::DepStream deps(this); deps.next(); ) {
2161     if (deps.check_dependency() != NULL) {
2162       found_check = true;
2163       NOT_DEBUG(break);
2164     }
2165   }
2166   return found_check;  // tell caller if we found anything
2167 }
2168 
2169 bool nmethod::check_dependency_on(DepChange& changes) {
2170   // What has happened:
2171   // 1) a new class dependee has been added
2172   // 2) dependee and all its super classes have been marked
2173   bool found_check = false;  // set true if we are upset
2174   for (Dependencies::DepStream deps(this); deps.next(); ) {
2175     // Evaluate only relevant dependencies.
2176     if (deps.spot_check_dependency_at(changes) != NULL) {
2177       found_check = true;
2178       NOT_DEBUG(break);
2179     }
2180   }
2181   return found_check;
2182 }
2183 
2184 bool nmethod::is_evol_dependent_on(Klass* dependee) {
2185   InstanceKlass *dependee_ik = InstanceKlass::cast(dependee);
2186   Array<Method*>* dependee_methods = dependee_ik->methods();
2187   for (Dependencies::DepStream deps(this); deps.next(); ) {
2188     if (deps.type() == Dependencies::evol_method) {
2189       Method* method = deps.method_argument(0);
2190       for (int j = 0; j < dependee_methods->length(); j++) {
2191         if (dependee_methods->at(j) == method) {
2192           // RC_TRACE macro has an embedded ResourceMark
2193           RC_TRACE(0x01000000,
2194             ("Found evol dependency of nmethod %s.%s(%s) compile_id=%d on method %s.%s(%s)",
2195             _method->method_holder()->external_name(),
2196             _method->name()->as_C_string(),
2197             _method->signature()->as_C_string(), compile_id(),
2198             method->method_holder()->external_name(),
2199             method->name()->as_C_string(),
2200             method->signature()->as_C_string()));
2201           if (TraceDependencies || LogCompilation)
2202             deps.log_dependency(dependee);
2203           return true;
2204         }
2205       }
2206     }
2207   }
2208   return false;
2209 }
2210 
2211 // Called from mark_for_deoptimization, when dependee is invalidated.
2212 bool nmethod::is_dependent_on_method(Method* dependee) {
2213   for (Dependencies::DepStream deps(this); deps.next(); ) {
2214     if (deps.type() != Dependencies::evol_method)
2215       continue;
2216     Method* method = deps.method_argument(0);
2217     if (method == dependee) return true;
2218   }
2219   return false;
2220 }
2221 
2222 
2223 bool nmethod::is_patchable_at(address instr_addr) {
2224   assert(insts_contains(instr_addr), "wrong nmethod used");
2225   if (is_zombie()) {
2226     // a zombie may never be patched
2227     return false;
2228   }
2229   return true;
2230 }
2231 
2232 
2233 address nmethod::continuation_for_implicit_exception(address pc) {
2234   // Exception happened outside inline-cache check code => we are inside
2235   // an active nmethod => use cpc to determine a return address
2236   int exception_offset = pc - code_begin();
2237   int cont_offset = ImplicitExceptionTable(this).at( exception_offset );
2238 #ifdef ASSERT
2239   if (cont_offset == 0) {
2240     Thread* thread = ThreadLocalStorage::get_thread_slow();
2241     ResetNoHandleMark rnm; // Might be called from LEAF/QUICK ENTRY
2242     HandleMark hm(thread);
2243     ResourceMark rm(thread);
2244     CodeBlob* cb = CodeCache::find_blob(pc);
2245     assert(cb != NULL && cb == this, "");
2246     tty->print_cr("implicit exception happened at " INTPTR_FORMAT, pc);
2247     print();
2248     method()->print_codes();
2249     print_code();
2250     print_pcs();
2251   }
2252 #endif
2253   if (cont_offset == 0) {
2254     // Let the normal error handling report the exception
2255     return NULL;
2256   }
2257   return code_begin() + cont_offset;
2258 }
2259 
2260 
2261 
2262 void nmethod_init() {
2263   // make sure you didn't forget to adjust the filler fields
2264   assert(sizeof(nmethod) % oopSize == 0, "nmethod size must be multiple of a word");
2265 }
2266 
2267 
2268 //-------------------------------------------------------------------------------------------
2269 
2270 
2271 // QQQ might we make this work from a frame??
2272 nmethodLocker::nmethodLocker(address pc) {
2273   CodeBlob* cb = CodeCache::find_blob(pc);
2274   guarantee(cb != NULL && cb->is_nmethod(), "bad pc for a nmethod found");
2275   _nm = (nmethod*)cb;
2276   lock_nmethod(_nm);
2277 }
2278 
2279 // Only JvmtiDeferredEvent::compiled_method_unload_event()
2280 // should pass zombie_ok == true.
2281 void nmethodLocker::lock_nmethod(nmethod* nm, bool zombie_ok) {
2282   if (nm == NULL)  return;
2283   Atomic::inc(&nm->_lock_count);
2284   guarantee(zombie_ok || !nm->is_zombie(), "cannot lock a zombie method");
2285 }
2286 
2287 void nmethodLocker::unlock_nmethod(nmethod* nm) {
2288   if (nm == NULL)  return;
2289   Atomic::dec(&nm->_lock_count);
2290   guarantee(nm->_lock_count >= 0, "unmatched nmethod lock/unlock");
2291 }
2292 
2293 
2294 // -----------------------------------------------------------------------------
2295 // nmethod::get_deopt_original_pc
2296 //
2297 // Return the original PC for the given PC if:
2298 // (a) the given PC belongs to a nmethod and
2299 // (b) it is a deopt PC
2300 address nmethod::get_deopt_original_pc(const frame* fr) {
2301   if (fr->cb() == NULL)  return NULL;
2302 
2303   nmethod* nm = fr->cb()->as_nmethod_or_null();
2304   if (nm != NULL && nm->is_deopt_pc(fr->pc()))
2305     return nm->get_original_pc(fr);
2306 
2307   return NULL;
2308 }
2309 
2310 
2311 // -----------------------------------------------------------------------------
2312 // MethodHandle
2313 
2314 bool nmethod::is_method_handle_return(address return_pc) {
2315   if (!has_method_handle_invokes())  return false;
2316   PcDesc* pd = pc_desc_at(return_pc);
2317   if (pd == NULL)
2318     return false;
2319   return pd->is_method_handle_invoke();
2320 }
2321 
2322 
2323 // -----------------------------------------------------------------------------
2324 // Verification
2325 
2326 class VerifyOopsClosure: public OopClosure {
2327   nmethod* _nm;
2328   bool     _ok;
2329 public:
2330   VerifyOopsClosure(nmethod* nm) : _nm(nm), _ok(true) { }
2331   bool ok() { return _ok; }
2332   virtual void do_oop(oop* p) {
2333     if ((*p) == NULL || (*p)->is_oop())  return;
2334     if (_ok) {
2335       _nm->print_nmethod(true);
2336       _ok = false;
2337     }
2338     tty->print_cr("*** non-oop "PTR_FORMAT" found at "PTR_FORMAT" (offset %d)",
2339                   (intptr_t)(*p), (intptr_t)p, (int)((intptr_t)p - (intptr_t)_nm));
2340   }
2341   virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
2342 };
2343 
2344 void nmethod::verify() {
2345 
2346   // Hmm. OSR methods can be deopted but not marked as zombie or not_entrant
2347   // seems odd.
2348 
2349   if( is_zombie() || is_not_entrant() )
2350     return;
2351 
2352   // Make sure all the entry points are correctly aligned for patching.
2353   NativeJump::check_verified_entry_alignment(entry_point(), verified_entry_point());
2354 
2355   // assert(method()->is_oop(), "must be valid");
2356 
2357   ResourceMark rm;
2358 
2359   if (!CodeCache::contains(this)) {
2360     fatal(err_msg("nmethod at " INTPTR_FORMAT " not in zone", this));
2361   }
2362 
2363   if(is_native_method() )
2364     return;
2365 
2366   nmethod* nm = CodeCache::find_nmethod(verified_entry_point());
2367   if (nm != this) {
2368     fatal(err_msg("findNMethod did not find this nmethod (" INTPTR_FORMAT ")",
2369                   this));
2370   }
2371 
2372   for (PcDesc* p = scopes_pcs_begin(); p < scopes_pcs_end(); p++) {
2373     if (! p->verify(this)) {
2374       tty->print_cr("\t\tin nmethod at " INTPTR_FORMAT " (pcs)", this);
2375     }
2376   }
2377 
2378   VerifyOopsClosure voc(this);
2379   oops_do(&voc);
2380   assert(voc.ok(), "embedded oops must be OK");
2381   verify_scavenge_root_oops();
2382 
2383   verify_scopes();
2384 }
2385 
2386 
2387 void nmethod::verify_interrupt_point(address call_site) {
2388   // This code does not work in release mode since
2389   // owns_lock only is available in debug mode.
2390   CompiledIC* ic = NULL;
2391   Thread *cur = Thread::current();
2392   if (CompiledIC_lock->owner() == cur ||
2393       ((cur->is_VM_thread() || cur->is_ConcurrentGC_thread()) &&
2394        SafepointSynchronize::is_at_safepoint())) {
2395     ic = CompiledIC_at(this, call_site);
2396     CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops());
2397   } else {
2398     MutexLocker ml_verify (CompiledIC_lock);
2399     ic = CompiledIC_at(this, call_site);
2400   }
2401   PcDesc* pd = pc_desc_at(ic->end_of_call());
2402   assert(pd != NULL, "PcDesc must exist");
2403   for (ScopeDesc* sd = new ScopeDesc(this, pd->scope_decode_offset(),
2404                                      pd->obj_decode_offset(), pd->should_reexecute(),
2405                                      pd->return_oop());
2406        !sd->is_top(); sd = sd->sender()) {
2407     sd->verify();
2408   }
2409 }
2410 
2411 void nmethod::verify_scopes() {
2412   if( !method() ) return;       // Runtime stubs have no scope
2413   if (method()->is_native()) return; // Ignore stub methods.
2414   // iterate through all interrupt point
2415   // and verify the debug information is valid.
2416   RelocIterator iter((nmethod*)this);
2417   while (iter.next()) {
2418     address stub = NULL;
2419     switch (iter.type()) {
2420       case relocInfo::virtual_call_type:
2421         verify_interrupt_point(iter.addr());
2422         break;
2423       case relocInfo::opt_virtual_call_type:
2424         stub = iter.opt_virtual_call_reloc()->static_stub();
2425         verify_interrupt_point(iter.addr());
2426         break;
2427       case relocInfo::static_call_type:
2428         stub = iter.static_call_reloc()->static_stub();
2429         //verify_interrupt_point(iter.addr());
2430         break;
2431       case relocInfo::runtime_call_type:
2432         address destination = iter.reloc()->value();
2433         // Right now there is no way to find out which entries support
2434         // an interrupt point.  It would be nice if we had this
2435         // information in a table.
2436         break;
2437     }
2438     assert(stub == NULL || stub_contains(stub), "static call stub outside stub section");
2439   }
2440 }
2441 
2442 
2443 // -----------------------------------------------------------------------------
2444 // Non-product code
2445 #ifndef PRODUCT
2446 
2447 class DebugScavengeRoot: public OopClosure {
2448   nmethod* _nm;
2449   bool     _ok;
2450 public:
2451   DebugScavengeRoot(nmethod* nm) : _nm(nm), _ok(true) { }
2452   bool ok() { return _ok; }
2453   virtual void do_oop(oop* p) {
2454     if ((*p) == NULL || !(*p)->is_scavengable())  return;
2455     if (_ok) {
2456       _nm->print_nmethod(true);
2457       _ok = false;
2458     }
2459     tty->print_cr("*** scavengable oop "PTR_FORMAT" found at "PTR_FORMAT" (offset %d)",
2460                   (intptr_t)(*p), (intptr_t)p, (int)((intptr_t)p - (intptr_t)_nm));
2461     (*p)->print();
2462   }
2463   virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
2464 };
2465 
2466 void nmethod::verify_scavenge_root_oops() {
2467   if (!on_scavenge_root_list()) {
2468     // Actually look inside, to verify the claim that it's clean.
2469     DebugScavengeRoot debug_scavenge_root(this);
2470     oops_do(&debug_scavenge_root);
2471     if (!debug_scavenge_root.ok())
2472       fatal("found an unadvertised bad scavengable oop in the code cache");
2473   }
2474   assert(scavenge_root_not_marked(), "");
2475 }
2476 
2477 #endif // PRODUCT
2478 
2479 // Printing operations
2480 
2481 void nmethod::print() const {
2482   ResourceMark rm;
2483   ttyLocker ttyl;   // keep the following output all in one block
2484 
2485   tty->print("Compiled method ");
2486 
2487   if (is_compiled_by_c1()) {
2488     tty->print("(c1) ");
2489   } else if (is_compiled_by_c2()) {
2490     tty->print("(c2) ");
2491   } else if (is_compiled_by_shark()) {
2492     tty->print("(shark) ");
2493   } else {
2494     tty->print("(nm) ");
2495   }
2496 
2497   print_on(tty, NULL);
2498 
2499   if (WizardMode) {
2500     tty->print("((nmethod*) "INTPTR_FORMAT ") ", this);
2501     tty->print(" for method " INTPTR_FORMAT , (address)method());
2502     tty->print(" { ");
2503     if (is_in_use())      tty->print("in_use ");
2504     if (is_not_entrant()) tty->print("not_entrant ");
2505     if (is_zombie())      tty->print("zombie ");
2506     if (is_unloaded())    tty->print("unloaded ");
2507     if (on_scavenge_root_list())  tty->print("scavenge_root ");
2508     tty->print_cr("}:");
2509   }
2510   if (size              () > 0) tty->print_cr(" total in heap  [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2511                                               (address)this,
2512                                               (address)this + size(),
2513                                               size());
2514   if (relocation_size   () > 0) tty->print_cr(" relocation     [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2515                                               relocation_begin(),
2516                                               relocation_end(),
2517                                               relocation_size());
2518   if (consts_size       () > 0) tty->print_cr(" constants      [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2519                                               consts_begin(),
2520                                               consts_end(),
2521                                               consts_size());
2522   if (insts_size        () > 0) tty->print_cr(" main code      [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2523                                               insts_begin(),
2524                                               insts_end(),
2525                                               insts_size());
2526   if (stub_size         () > 0) tty->print_cr(" stub code      [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2527                                               stub_begin(),
2528                                               stub_end(),
2529                                               stub_size());
2530   if (oops_size         () > 0) tty->print_cr(" oops           [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2531                                               oops_begin(),
2532                                               oops_end(),
2533                                               oops_size());
2534   if (metadata_size      () > 0) tty->print_cr(" metadata       [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2535                                               metadata_begin(),
2536                                               metadata_end(),
2537                                               metadata_size());
2538   if (scopes_data_size  () > 0) tty->print_cr(" scopes data    [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2539                                               scopes_data_begin(),
2540                                               scopes_data_end(),
2541                                               scopes_data_size());
2542   if (scopes_pcs_size   () > 0) tty->print_cr(" scopes pcs     [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2543                                               scopes_pcs_begin(),
2544                                               scopes_pcs_end(),
2545                                               scopes_pcs_size());
2546   if (dependencies_size () > 0) tty->print_cr(" dependencies   [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2547                                               dependencies_begin(),
2548                                               dependencies_end(),
2549                                               dependencies_size());
2550   if (handler_table_size() > 0) tty->print_cr(" handler table  [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2551                                               handler_table_begin(),
2552                                               handler_table_end(),
2553                                               handler_table_size());
2554   if (nul_chk_table_size() > 0) tty->print_cr(" nul chk table  [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2555                                               nul_chk_table_begin(),
2556                                               nul_chk_table_end(),
2557                                               nul_chk_table_size());
2558 }
2559 
2560 void nmethod::print_code() {
2561   HandleMark hm;
2562   ResourceMark m;
2563   Disassembler::decode(this);
2564 }
2565 
2566 
2567 #ifndef PRODUCT
2568 
2569 void nmethod::print_scopes() {
2570   // Find the first pc desc for all scopes in the code and print it.
2571   ResourceMark rm;
2572   for (PcDesc* p = scopes_pcs_begin(); p < scopes_pcs_end(); p++) {
2573     if (p->scope_decode_offset() == DebugInformationRecorder::serialized_null)
2574       continue;
2575 
2576     ScopeDesc* sd = scope_desc_at(p->real_pc(this));
2577     sd->print_on(tty, p);
2578   }
2579 }
2580 
2581 void nmethod::print_dependencies() {
2582   ResourceMark rm;
2583   ttyLocker ttyl;   // keep the following output all in one block
2584   tty->print_cr("Dependencies:");
2585   for (Dependencies::DepStream deps(this); deps.next(); ) {
2586     deps.print_dependency();
2587     Klass* ctxk = deps.context_type();
2588     if (ctxk != NULL) {
2589       if (ctxk->oop_is_instance() && ((InstanceKlass*)ctxk)->is_dependent_nmethod(this)) {
2590         tty->print_cr("   [nmethod<=klass]%s", ctxk->external_name());
2591       }
2592     }
2593     deps.log_dependency();  // put it into the xml log also
2594   }
2595 }
2596 
2597 
2598 void nmethod::print_relocations() {
2599   ResourceMark m;       // in case methods get printed via the debugger
2600   tty->print_cr("relocations:");
2601   RelocIterator iter(this);
2602   iter.print();
2603   if (UseRelocIndex) {
2604     jint* index_end   = (jint*)relocation_end() - 1;
2605     jint  index_size  = *index_end;
2606     jint* index_start = (jint*)( (address)index_end - index_size );
2607     tty->print_cr("    index @" INTPTR_FORMAT ": index_size=%d", index_start, index_size);
2608     if (index_size > 0) {
2609       jint* ip;
2610       for (ip = index_start; ip+2 <= index_end; ip += 2)
2611         tty->print_cr("  (%d %d) addr=" INTPTR_FORMAT " @" INTPTR_FORMAT,
2612                       ip[0],
2613                       ip[1],
2614                       header_end()+ip[0],
2615                       relocation_begin()-1+ip[1]);
2616       for (; ip < index_end; ip++)
2617         tty->print_cr("  (%d ?)", ip[0]);
2618       tty->print_cr("          @" INTPTR_FORMAT ": index_size=%d", ip, *ip++);
2619       tty->print_cr("reloc_end @" INTPTR_FORMAT ":", ip);
2620     }
2621   }
2622 }
2623 
2624 
2625 void nmethod::print_pcs() {
2626   ResourceMark m;       // in case methods get printed via debugger
2627   tty->print_cr("pc-bytecode offsets:");
2628   for (PcDesc* p = scopes_pcs_begin(); p < scopes_pcs_end(); p++) {
2629     p->print(this);
2630   }
2631 }
2632 
2633 #endif // PRODUCT
2634 
2635 const char* nmethod::reloc_string_for(u_char* begin, u_char* end) {
2636   RelocIterator iter(this, begin, end);
2637   bool have_one = false;
2638   while (iter.next()) {
2639     have_one = true;
2640     switch (iter.type()) {
2641         case relocInfo::none:                  return "no_reloc";
2642         case relocInfo::oop_type: {
2643           stringStream st;
2644           oop_Relocation* r = iter.oop_reloc();
2645           oop obj = r->oop_value();
2646           st.print("oop(");
2647           if (obj == NULL) st.print("NULL");
2648           else obj->print_value_on(&st);
2649           st.print(")");
2650           return st.as_string();
2651         }
2652         case relocInfo::metadata_type: {
2653           stringStream st;
2654           metadata_Relocation* r = iter.metadata_reloc();
2655           Metadata* obj = r->metadata_value();
2656           st.print("metadata(");
2657           if (obj == NULL) st.print("NULL");
2658           else obj->print_value_on(&st);
2659           st.print(")");
2660           return st.as_string();
2661         }
2662         case relocInfo::virtual_call_type:     return "virtual_call";
2663         case relocInfo::opt_virtual_call_type: return "optimized virtual_call";
2664         case relocInfo::static_call_type:      return "static_call";
2665         case relocInfo::static_stub_type:      return "static_stub";
2666         case relocInfo::runtime_call_type:     return "runtime_call";
2667         case relocInfo::external_word_type:    return "external_word";
2668         case relocInfo::internal_word_type:    return "internal_word";
2669         case relocInfo::section_word_type:     return "section_word";
2670         case relocInfo::poll_type:             return "poll";
2671         case relocInfo::poll_return_type:      return "poll_return";
2672         case relocInfo::type_mask:             return "type_bit_mask";
2673     }
2674   }
2675   return have_one ? "other" : NULL;
2676 }
2677 
2678 // Return a the last scope in (begin..end]
2679 ScopeDesc* nmethod::scope_desc_in(address begin, address end) {
2680   PcDesc* p = pc_desc_near(begin+1);
2681   if (p != NULL && p->real_pc(this) <= end) {
2682     return new ScopeDesc(this, p->scope_decode_offset(),
2683                          p->obj_decode_offset(), p->should_reexecute(),
2684                          p->return_oop());
2685   }
2686   return NULL;
2687 }
2688 
2689 void nmethod::print_nmethod_labels(outputStream* stream, address block_begin) const {
2690   if (block_begin == entry_point())             stream->print_cr("[Entry Point]");
2691   if (block_begin == verified_entry_point())    stream->print_cr("[Verified Entry Point]");
2692   if (block_begin == exception_begin())         stream->print_cr("[Exception Handler]");
2693   if (block_begin == stub_begin())              stream->print_cr("[Stub Code]");
2694   if (block_begin == deopt_handler_begin())     stream->print_cr("[Deopt Handler Code]");
2695 
2696   if (has_method_handle_invokes())
2697     if (block_begin == deopt_mh_handler_begin())  stream->print_cr("[Deopt MH Handler Code]");
2698 
2699   if (block_begin == consts_begin())            stream->print_cr("[Constants]");
2700 
2701   if (block_begin == entry_point()) {
2702     methodHandle m = method();
2703     if (m.not_null()) {
2704       stream->print("  # ");
2705       m->print_value_on(stream);
2706       stream->cr();
2707     }
2708     if (m.not_null() && !is_osr_method()) {
2709       ResourceMark rm;
2710       int sizeargs = m->size_of_parameters();
2711       BasicType* sig_bt = NEW_RESOURCE_ARRAY(BasicType, sizeargs);
2712       VMRegPair* regs   = NEW_RESOURCE_ARRAY(VMRegPair, sizeargs);
2713       {
2714         int sig_index = 0;
2715         if (!m->is_static())
2716           sig_bt[sig_index++] = T_OBJECT; // 'this'
2717         for (SignatureStream ss(m->signature()); !ss.at_return_type(); ss.next()) {
2718           BasicType t = ss.type();
2719           sig_bt[sig_index++] = t;
2720           if (type2size[t] == 2) {
2721             sig_bt[sig_index++] = T_VOID;
2722           } else {
2723             assert(type2size[t] == 1, "size is 1 or 2");
2724           }
2725         }
2726         assert(sig_index == sizeargs, "");
2727       }
2728       const char* spname = "sp"; // make arch-specific?
2729       intptr_t out_preserve = SharedRuntime::java_calling_convention(sig_bt, regs, sizeargs, false);
2730       int stack_slot_offset = this->frame_size() * wordSize;
2731       int tab1 = 14, tab2 = 24;
2732       int sig_index = 0;
2733       int arg_index = (m->is_static() ? 0 : -1);
2734       bool did_old_sp = false;
2735       for (SignatureStream ss(m->signature()); !ss.at_return_type(); ) {
2736         bool at_this = (arg_index == -1);
2737         bool at_old_sp = false;
2738         BasicType t = (at_this ? T_OBJECT : ss.type());
2739         assert(t == sig_bt[sig_index], "sigs in sync");
2740         if (at_this)
2741           stream->print("  # this: ");
2742         else
2743           stream->print("  # parm%d: ", arg_index);
2744         stream->move_to(tab1);
2745         VMReg fst = regs[sig_index].first();
2746         VMReg snd = regs[sig_index].second();
2747         if (fst->is_reg()) {
2748           stream->print("%s", fst->name());
2749           if (snd->is_valid())  {
2750             stream->print(":%s", snd->name());
2751           }
2752         } else if (fst->is_stack()) {
2753           int offset = fst->reg2stack() * VMRegImpl::stack_slot_size + stack_slot_offset;
2754           if (offset == stack_slot_offset)  at_old_sp = true;
2755           stream->print("[%s+0x%x]", spname, offset);
2756         } else {
2757           stream->print("reg%d:%d??", (int)(intptr_t)fst, (int)(intptr_t)snd);
2758         }
2759         stream->print(" ");
2760         stream->move_to(tab2);
2761         stream->print("= ");
2762         if (at_this) {
2763           m->method_holder()->print_value_on(stream);
2764         } else {
2765           bool did_name = false;
2766           if (!at_this && ss.is_object()) {
2767             Symbol* name = ss.as_symbol_or_null();
2768             if (name != NULL) {
2769               name->print_value_on(stream);
2770               did_name = true;
2771             }
2772           }
2773           if (!did_name)
2774             stream->print("%s", type2name(t));
2775         }
2776         if (at_old_sp) {
2777           stream->print("  (%s of caller)", spname);
2778           did_old_sp = true;
2779         }
2780         stream->cr();
2781         sig_index += type2size[t];
2782         arg_index += 1;
2783         if (!at_this)  ss.next();
2784       }
2785       if (!did_old_sp) {
2786         stream->print("  # ");
2787         stream->move_to(tab1);
2788         stream->print("[%s+0x%x]", spname, stack_slot_offset);
2789         stream->print("  (%s of caller)", spname);
2790         stream->cr();
2791       }
2792     }
2793   }
2794 }
2795 
2796 void nmethod::print_code_comment_on(outputStream* st, int column, u_char* begin, u_char* end) {
2797   // First, find an oopmap in (begin, end].
2798   // We use the odd half-closed interval so that oop maps and scope descs
2799   // which are tied to the byte after a call are printed with the call itself.
2800   address base = code_begin();
2801   OopMapSet* oms = oop_maps();
2802   if (oms != NULL) {
2803     for (int i = 0, imax = oms->size(); i < imax; i++) {
2804       OopMap* om = oms->at(i);
2805       address pc = base + om->offset();
2806       if (pc > begin) {
2807         if (pc <= end) {
2808           st->move_to(column);
2809           st->print("; ");
2810           om->print_on(st);
2811         }
2812         break;
2813       }
2814     }
2815   }
2816 
2817   // Print any debug info present at this pc.
2818   ScopeDesc* sd  = scope_desc_in(begin, end);
2819   if (sd != NULL) {
2820     st->move_to(column);
2821     if (sd->bci() == SynchronizationEntryBCI) {
2822       st->print(";*synchronization entry");
2823     } else {
2824       if (sd->method() == NULL) {
2825         st->print("method is NULL");
2826       } else if (sd->method()->is_native()) {
2827         st->print("method is native");
2828       } else {
2829         Bytecodes::Code bc = sd->method()->java_code_at(sd->bci());
2830         st->print(";*%s", Bytecodes::name(bc));
2831         switch (bc) {
2832         case Bytecodes::_invokevirtual:
2833         case Bytecodes::_invokespecial:
2834         case Bytecodes::_invokestatic:
2835         case Bytecodes::_invokeinterface:
2836           {
2837             Bytecode_invoke invoke(sd->method(), sd->bci());
2838             st->print(" ");
2839             if (invoke.name() != NULL)
2840               invoke.name()->print_symbol_on(st);
2841             else
2842               st->print("<UNKNOWN>");
2843             break;
2844           }
2845         case Bytecodes::_getfield:
2846         case Bytecodes::_putfield:
2847         case Bytecodes::_getstatic:
2848         case Bytecodes::_putstatic:
2849           {
2850             Bytecode_field field(sd->method(), sd->bci());
2851             st->print(" ");
2852             if (field.name() != NULL)
2853               field.name()->print_symbol_on(st);
2854             else
2855               st->print("<UNKNOWN>");
2856           }
2857         }
2858       }
2859     }
2860 
2861     // Print all scopes
2862     for (;sd != NULL; sd = sd->sender()) {
2863       st->move_to(column);
2864       st->print("; -");
2865       if (sd->method() == NULL) {
2866         st->print("method is NULL");
2867       } else {
2868         sd->method()->print_short_name(st);
2869       }
2870       int lineno = sd->method()->line_number_from_bci(sd->bci());
2871       if (lineno != -1) {
2872         st->print("@%d (line %d)", sd->bci(), lineno);
2873       } else {
2874         st->print("@%d", sd->bci());
2875       }
2876       st->cr();
2877     }
2878   }
2879 
2880   // Print relocation information
2881   const char* str = reloc_string_for(begin, end);
2882   if (str != NULL) {
2883     if (sd != NULL) st->cr();
2884     st->move_to(column);
2885     st->print(";   {%s}", str);
2886   }
2887   int cont_offset = ImplicitExceptionTable(this).at(begin - code_begin());
2888   if (cont_offset != 0) {
2889     st->move_to(column);
2890     st->print("; implicit exception: dispatches to " INTPTR_FORMAT, code_begin() + cont_offset);
2891   }
2892 
2893 }
2894 
2895 #ifndef PRODUCT
2896 
2897 void nmethod::print_value_on(outputStream* st) const {
2898   st->print("nmethod");
2899   print_on(st, NULL);
2900 }
2901 
2902 void nmethod::print_calls(outputStream* st) {
2903   RelocIterator iter(this);
2904   while (iter.next()) {
2905     switch (iter.type()) {
2906     case relocInfo::virtual_call_type:
2907     case relocInfo::opt_virtual_call_type: {
2908       VerifyMutexLocker mc(CompiledIC_lock);
2909       CompiledIC_at(iter.reloc())->print();
2910       break;
2911     }
2912     case relocInfo::static_call_type:
2913       st->print_cr("Static call at " INTPTR_FORMAT, iter.reloc()->addr());
2914       compiledStaticCall_at(iter.reloc())->print();
2915       break;
2916     }
2917   }
2918 }
2919 
2920 void nmethod::print_handler_table() {
2921   ExceptionHandlerTable(this).print();
2922 }
2923 
2924 void nmethod::print_nul_chk_table() {
2925   ImplicitExceptionTable(this).print(code_begin());
2926 }
2927 
2928 void nmethod::print_statistics() {
2929   ttyLocker ttyl;
2930   if (xtty != NULL)  xtty->head("statistics type='nmethod'");
2931   nmethod_stats.print_native_nmethod_stats();
2932   nmethod_stats.print_nmethod_stats();
2933   DebugInformationRecorder::print_statistics();
2934   nmethod_stats.print_pc_stats();
2935   Dependencies::print_statistics();
2936   if (xtty != NULL)  xtty->tail("statistics");
2937 }
2938 
2939 #endif // PRODUCT