1 /*
   2  * Copyright (c) 1997, 2010, 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 "incls/_precompiled.incl"
  26 # include "incls/_nmethod.cpp.incl"
  27 
  28 #ifdef DTRACE_ENABLED
  29 
  30 // Only bother with this argument setup if dtrace is available
  31 
  32 HS_DTRACE_PROBE_DECL8(hotspot, compiled__method__load,
  33   const char*, int, const char*, int, const char*, int, void*, size_t);
  34 
  35 HS_DTRACE_PROBE_DECL6(hotspot, compiled__method__unload,
  36   char*, int, char*, int, char*, int);
  37 
  38 #define DTRACE_METHOD_UNLOAD_PROBE(method)                                \
  39   {                                                                       \
  40     methodOop m = (method);                                               \
  41     if (m != NULL) {                                                      \
  42       symbolOop klass_name = m->klass_name();                             \
  43       symbolOop name = m->name();                                         \
  44       symbolOop signature = m->signature();                               \
  45       HS_DTRACE_PROBE6(hotspot, compiled__method__unload,                 \
  46         klass_name->bytes(), klass_name->utf8_length(),                   \
  47         name->bytes(), name->utf8_length(),                               \
  48         signature->bytes(), signature->utf8_length());                    \
  49     }                                                                     \
  50   }
  51 
  52 #else //  ndef DTRACE_ENABLED
  53 
  54 #define DTRACE_METHOD_UNLOAD_PROBE(method)
  55 
  56 #endif
  57 
  58 bool nmethod::is_compiled_by_c1() const {
  59   if (compiler() == NULL || method() == NULL)  return false;  // can happen during debug printing
  60   if (is_native_method()) return false;
  61   return compiler()->is_c1();
  62 }
  63 bool nmethod::is_compiled_by_c2() const {
  64   if (compiler() == NULL || method() == NULL)  return false;  // can happen during debug printing
  65   if (is_native_method()) return false;
  66   return compiler()->is_c2();
  67 }
  68 
  69 
  70 
  71 //---------------------------------------------------------------------------------
  72 // NMethod statistics
  73 // They are printed under various flags, including:
  74 //   PrintC1Statistics, PrintOptoStatistics, LogVMOutput, and LogCompilation.
  75 // (In the latter two cases, they like other stats are printed to the log only.)
  76 
  77 #ifndef PRODUCT
  78 // These variables are put into one block to reduce relocations
  79 // and make it simpler to print from the debugger.
  80 static
  81 struct nmethod_stats_struct {
  82   int nmethod_count;
  83   int total_size;
  84   int relocation_size;
  85   int code_size;
  86   int stub_size;
  87   int consts_size;
  88   int scopes_data_size;
  89   int scopes_pcs_size;
  90   int dependencies_size;
  91   int handler_table_size;
  92   int nul_chk_table_size;
  93   int oops_size;
  94 
  95   void note_nmethod(nmethod* nm) {
  96     nmethod_count += 1;
  97     total_size          += nm->size();
  98     relocation_size     += nm->relocation_size();
  99     code_size           += nm->code_size();
 100     stub_size           += nm->stub_size();
 101     consts_size         += nm->consts_size();
 102     oops_size           += nm->oops_size();
 103     scopes_data_size    += nm->scopes_data_size();
 104     scopes_pcs_size     += nm->scopes_pcs_size();
 105     dependencies_size   += nm->dependencies_size();
 106     handler_table_size  += nm->handler_table_size();
 107     nul_chk_table_size  += nm->nul_chk_table_size();
 108   }
 109   void print_nmethod_stats() {
 110     if (nmethod_count == 0)  return;
 111     tty->print_cr("Statistics for %d bytecoded nmethods:", nmethod_count);
 112     if (total_size != 0)          tty->print_cr(" total in heap  = %d", total_size);
 113     if (relocation_size != 0)     tty->print_cr(" relocation     = %d", relocation_size);
 114     if (code_size != 0)           tty->print_cr(" main code      = %d", code_size);
 115     if (stub_size != 0)           tty->print_cr(" stub code      = %d", stub_size);
 116     if (consts_size != 0)         tty->print_cr(" constants      = %d", consts_size);
 117     if (oops_size != 0)           tty->print_cr(" oops           = %d", oops_size);
 118     if (scopes_data_size != 0)    tty->print_cr(" scopes data    = %d", scopes_data_size);
 119     if (scopes_pcs_size != 0)     tty->print_cr(" scopes pcs     = %d", scopes_pcs_size);
 120     if (dependencies_size != 0)   tty->print_cr(" dependencies   = %d", dependencies_size);
 121     if (handler_table_size != 0)  tty->print_cr(" handler table  = %d", handler_table_size);
 122     if (nul_chk_table_size != 0)  tty->print_cr(" nul chk table  = %d", nul_chk_table_size);
 123   }
 124 
 125   int native_nmethod_count;
 126   int native_total_size;
 127   int native_relocation_size;
 128   int native_code_size;
 129   int native_oops_size;
 130   void note_native_nmethod(nmethod* nm) {
 131     native_nmethod_count += 1;
 132     native_total_size       += nm->size();
 133     native_relocation_size  += nm->relocation_size();
 134     native_code_size        += nm->code_size();
 135     native_oops_size        += nm->oops_size();
 136   }
 137   void print_native_nmethod_stats() {
 138     if (native_nmethod_count == 0)  return;
 139     tty->print_cr("Statistics for %d native nmethods:", native_nmethod_count);
 140     if (native_total_size != 0)       tty->print_cr(" N. total size  = %d", native_total_size);
 141     if (native_relocation_size != 0)  tty->print_cr(" N. relocation  = %d", native_relocation_size);
 142     if (native_code_size != 0)        tty->print_cr(" N. main code   = %d", native_code_size);
 143     if (native_oops_size != 0)        tty->print_cr(" N. oops        = %d", native_oops_size);
 144   }
 145 
 146   int pc_desc_resets;   // number of resets (= number of caches)
 147   int pc_desc_queries;  // queries to nmethod::find_pc_desc
 148   int pc_desc_approx;   // number of those which have approximate true
 149   int pc_desc_repeats;  // number of _last_pc_desc hits
 150   int pc_desc_hits;     // number of LRU cache hits
 151   int pc_desc_tests;    // total number of PcDesc examinations
 152   int pc_desc_searches; // total number of quasi-binary search steps
 153   int pc_desc_adds;     // number of LUR cache insertions
 154 
 155   void print_pc_stats() {
 156     tty->print_cr("PcDesc Statistics:  %d queries, %.2f comparisons per query",
 157                   pc_desc_queries,
 158                   (double)(pc_desc_tests + pc_desc_searches)
 159                   / pc_desc_queries);
 160     tty->print_cr("  caches=%d queries=%d/%d, hits=%d+%d, tests=%d+%d, adds=%d",
 161                   pc_desc_resets,
 162                   pc_desc_queries, pc_desc_approx,
 163                   pc_desc_repeats, pc_desc_hits,
 164                   pc_desc_tests, pc_desc_searches, pc_desc_adds);
 165   }
 166 } nmethod_stats;
 167 #endif //PRODUCT
 168 
 169 //---------------------------------------------------------------------------------
 170 
 171 
 172 // The _unwind_handler is a special marker address, which says that
 173 // for given exception oop and address, the frame should be removed
 174 // as the tuple cannot be caught in the nmethod
 175 address ExceptionCache::_unwind_handler = (address) -1;
 176 
 177 
 178 ExceptionCache::ExceptionCache(Handle exception, address pc, address handler) {
 179   assert(pc != NULL, "Must be non null");
 180   assert(exception.not_null(), "Must be non null");
 181   assert(handler != NULL, "Must be non null");
 182 
 183   _count = 0;
 184   _exception_type = exception->klass();
 185   _next = NULL;
 186 
 187   add_address_and_handler(pc,handler);
 188 }
 189 
 190 
 191 address ExceptionCache::match(Handle exception, address pc) {
 192   assert(pc != NULL,"Must be non null");
 193   assert(exception.not_null(),"Must be non null");
 194   if (exception->klass() == exception_type()) {
 195     return (test_address(pc));
 196   }
 197 
 198   return NULL;
 199 }
 200 
 201 
 202 bool ExceptionCache::match_exception_with_space(Handle exception) {
 203   assert(exception.not_null(),"Must be non null");
 204   if (exception->klass() == exception_type() && count() < cache_size) {
 205     return true;
 206   }
 207   return false;
 208 }
 209 
 210 
 211 address ExceptionCache::test_address(address addr) {
 212   for (int i=0; i<count(); i++) {
 213     if (pc_at(i) == addr) {
 214       return handler_at(i);
 215     }
 216   }
 217   return NULL;
 218 }
 219 
 220 
 221 bool ExceptionCache::add_address_and_handler(address addr, address handler) {
 222   if (test_address(addr) == handler) return true;
 223   if (count() < cache_size) {
 224     set_pc_at(count(),addr);
 225     set_handler_at(count(), handler);
 226     increment_count();
 227     return true;
 228   }
 229   return false;
 230 }
 231 
 232 
 233 // private method for handling exception cache
 234 // These methods are private, and used to manipulate the exception cache
 235 // directly.
 236 ExceptionCache* nmethod::exception_cache_entry_for_exception(Handle exception) {
 237   ExceptionCache* ec = exception_cache();
 238   while (ec != NULL) {
 239     if (ec->match_exception_with_space(exception)) {
 240       return ec;
 241     }
 242     ec = ec->next();
 243   }
 244   return NULL;
 245 }
 246 
 247 
 248 //-----------------------------------------------------------------------------
 249 
 250 
 251 // Helper used by both find_pc_desc methods.
 252 static inline bool match_desc(PcDesc* pc, int pc_offset, bool approximate) {
 253   NOT_PRODUCT(++nmethod_stats.pc_desc_tests);
 254   if (!approximate)
 255     return pc->pc_offset() == pc_offset;
 256   else
 257     return (pc-1)->pc_offset() < pc_offset && pc_offset <= pc->pc_offset();
 258 }
 259 
 260 void PcDescCache::reset_to(PcDesc* initial_pc_desc) {
 261   if (initial_pc_desc == NULL) {
 262     _last_pc_desc = NULL;  // native method
 263     return;
 264   }
 265   NOT_PRODUCT(++nmethod_stats.pc_desc_resets);
 266   // reset the cache by filling it with benign (non-null) values
 267   assert(initial_pc_desc->pc_offset() < 0, "must be sentinel");
 268   _last_pc_desc = initial_pc_desc + 1;  // first valid one is after sentinel
 269   for (int i = 0; i < cache_size; i++)
 270     _pc_descs[i] = initial_pc_desc;
 271 }
 272 
 273 PcDesc* PcDescCache::find_pc_desc(int pc_offset, bool approximate) {
 274   NOT_PRODUCT(++nmethod_stats.pc_desc_queries);
 275   NOT_PRODUCT(if (approximate)  ++nmethod_stats.pc_desc_approx);
 276 
 277   // In order to prevent race conditions do not load cache elements
 278   // repeatedly, but use a local copy:
 279   PcDesc* res;
 280 
 281   // Step one:  Check the most recently returned value.
 282   res = _last_pc_desc;
 283   if (res == NULL)  return NULL;  // native method; no PcDescs at all
 284   if (match_desc(res, pc_offset, approximate)) {
 285     NOT_PRODUCT(++nmethod_stats.pc_desc_repeats);
 286     return res;
 287   }
 288 
 289   // Step two:  Check the LRU cache.
 290   for (int i = 0; i < cache_size; i++) {
 291     res = _pc_descs[i];
 292     if (res->pc_offset() < 0)  break;  // optimization: skip empty cache
 293     if (match_desc(res, pc_offset, approximate)) {
 294       NOT_PRODUCT(++nmethod_stats.pc_desc_hits);
 295       _last_pc_desc = res;  // record this cache hit in case of repeat
 296       return res;
 297     }
 298   }
 299 
 300   // Report failure.
 301   return NULL;
 302 }
 303 
 304 void PcDescCache::add_pc_desc(PcDesc* pc_desc) {
 305   NOT_PRODUCT(++nmethod_stats.pc_desc_adds);
 306   // Update the LRU cache by shifting pc_desc forward:
 307   for (int i = 0; i < cache_size; i++)  {
 308     PcDesc* next = _pc_descs[i];
 309     _pc_descs[i] = pc_desc;
 310     pc_desc = next;
 311   }
 312   // Note:  Do not update _last_pc_desc.  It fronts for the LRU cache.
 313 }
 314 
 315 // adjust pcs_size so that it is a multiple of both oopSize and
 316 // sizeof(PcDesc) (assumes that if sizeof(PcDesc) is not a multiple
 317 // of oopSize, then 2*sizeof(PcDesc) is)
 318 static int  adjust_pcs_size(int pcs_size) {
 319   int nsize = round_to(pcs_size,   oopSize);
 320   if ((nsize % sizeof(PcDesc)) != 0) {
 321     nsize = pcs_size + sizeof(PcDesc);
 322   }
 323   assert((nsize %  oopSize) == 0, "correct alignment");
 324   return nsize;
 325 }
 326 
 327 //-----------------------------------------------------------------------------
 328 
 329 
 330 void nmethod::add_exception_cache_entry(ExceptionCache* new_entry) {
 331   assert(ExceptionCache_lock->owned_by_self(),"Must hold the ExceptionCache_lock");
 332   assert(new_entry != NULL,"Must be non null");
 333   assert(new_entry->next() == NULL, "Must be null");
 334 
 335   if (exception_cache() != NULL) {
 336     new_entry->set_next(exception_cache());
 337   }
 338   set_exception_cache(new_entry);
 339 }
 340 
 341 void nmethod::remove_from_exception_cache(ExceptionCache* ec) {
 342   ExceptionCache* prev = NULL;
 343   ExceptionCache* curr = exception_cache();
 344   assert(curr != NULL, "nothing to remove");
 345   // find the previous and next entry of ec
 346   while (curr != ec) {
 347     prev = curr;
 348     curr = curr->next();
 349     assert(curr != NULL, "ExceptionCache not found");
 350   }
 351   // now: curr == ec
 352   ExceptionCache* next = curr->next();
 353   if (prev == NULL) {
 354     set_exception_cache(next);
 355   } else {
 356     prev->set_next(next);
 357   }
 358   delete curr;
 359 }
 360 
 361 
 362 // public method for accessing the exception cache
 363 // These are the public access methods.
 364 address nmethod::handler_for_exception_and_pc(Handle exception, address pc) {
 365   // We never grab a lock to read the exception cache, so we may
 366   // have false negatives. This is okay, as it can only happen during
 367   // the first few exception lookups for a given nmethod.
 368   ExceptionCache* ec = exception_cache();
 369   while (ec != NULL) {
 370     address ret_val;
 371     if ((ret_val = ec->match(exception,pc)) != NULL) {
 372       return ret_val;
 373     }
 374     ec = ec->next();
 375   }
 376   return NULL;
 377 }
 378 
 379 
 380 void nmethod::add_handler_for_exception_and_pc(Handle exception, address pc, address handler) {
 381   // There are potential race conditions during exception cache updates, so we
 382   // must own the ExceptionCache_lock before doing ANY modifications. Because
 383   // we don't lock during reads, it is possible to have several threads attempt
 384   // to update the cache with the same data. We need to check for already inserted
 385   // copies of the current data before adding it.
 386 
 387   MutexLocker ml(ExceptionCache_lock);
 388   ExceptionCache* target_entry = exception_cache_entry_for_exception(exception);
 389 
 390   if (target_entry == NULL || !target_entry->add_address_and_handler(pc,handler)) {
 391     target_entry = new ExceptionCache(exception,pc,handler);
 392     add_exception_cache_entry(target_entry);
 393   }
 394 }
 395 
 396 
 397 //-------------end of code for ExceptionCache--------------
 398 
 399 
 400 void nmFlags::clear() {
 401   assert(sizeof(nmFlags) == sizeof(int), "using more than one word for nmFlags");
 402   *(jint*)this = 0;
 403 }
 404 
 405 int nmethod::total_size() const {
 406   return
 407     code_size()          +
 408     stub_size()          +
 409     consts_size()        +
 410     scopes_data_size()   +
 411     scopes_pcs_size()    +
 412     handler_table_size() +
 413     nul_chk_table_size();
 414 }
 415 
 416 const char* nmethod::compile_kind() const {
 417   if (is_osr_method())     return "osr";
 418   if (method() != NULL && is_native_method())  return "c2n";
 419   return NULL;
 420 }
 421 
 422 // %%% This variable is no longer used?
 423 int nmethod::_zombie_instruction_size = NativeJump::instruction_size;
 424 
 425 
 426 nmethod* nmethod::new_native_nmethod(methodHandle method,
 427   CodeBuffer *code_buffer,
 428   int vep_offset,
 429   int frame_complete,
 430   int frame_size,
 431   ByteSize basic_lock_owner_sp_offset,
 432   ByteSize basic_lock_sp_offset,
 433   OopMapSet* oop_maps) {
 434   // create nmethod
 435   nmethod* nm = NULL;
 436   {
 437     MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
 438     int native_nmethod_size = allocation_size(code_buffer, sizeof(nmethod));
 439     CodeOffsets offsets;
 440     offsets.set_value(CodeOffsets::Verified_Entry, vep_offset);
 441     offsets.set_value(CodeOffsets::Frame_Complete, frame_complete);
 442     nm = new (native_nmethod_size)
 443       nmethod(method(), native_nmethod_size, &offsets,
 444               code_buffer, frame_size,
 445               basic_lock_owner_sp_offset, basic_lock_sp_offset,
 446               oop_maps);
 447     NOT_PRODUCT(if (nm != NULL)  nmethod_stats.note_native_nmethod(nm));
 448     if (PrintAssembly && nm != NULL)
 449       Disassembler::decode(nm);
 450   }
 451   // verify nmethod
 452   debug_only(if (nm) nm->verify();) // might block
 453 
 454   if (nm != NULL) {
 455     nm->log_new_nmethod();
 456   }
 457 
 458   return nm;
 459 }
 460 
 461 #ifdef HAVE_DTRACE_H
 462 nmethod* nmethod::new_dtrace_nmethod(methodHandle method,
 463                                      CodeBuffer *code_buffer,
 464                                      int vep_offset,
 465                                      int trap_offset,
 466                                      int frame_complete,
 467                                      int frame_size) {
 468   // create nmethod
 469   nmethod* nm = NULL;
 470   {
 471     MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
 472     int nmethod_size = allocation_size(code_buffer, sizeof(nmethod));
 473     CodeOffsets offsets;
 474     offsets.set_value(CodeOffsets::Verified_Entry, vep_offset);
 475     offsets.set_value(CodeOffsets::Dtrace_trap, trap_offset);
 476     offsets.set_value(CodeOffsets::Frame_Complete, frame_complete);
 477 
 478     nm = new (nmethod_size) nmethod(method(), nmethod_size, &offsets, code_buffer, frame_size);
 479 
 480     NOT_PRODUCT(if (nm != NULL)  nmethod_stats.note_nmethod(nm));
 481     if (PrintAssembly && nm != NULL)
 482       Disassembler::decode(nm);
 483   }
 484   // verify nmethod
 485   debug_only(if (nm) nm->verify();) // might block
 486 
 487   if (nm != NULL) {
 488     nm->log_new_nmethod();
 489   }
 490 
 491   return nm;
 492 }
 493 
 494 #endif // def HAVE_DTRACE_H
 495 
 496 nmethod* nmethod::new_nmethod(methodHandle method,
 497   int compile_id,
 498   int entry_bci,
 499   CodeOffsets* offsets,
 500   int orig_pc_offset,
 501   DebugInformationRecorder* debug_info,
 502   Dependencies* dependencies,
 503   CodeBuffer* code_buffer, int frame_size,
 504   OopMapSet* oop_maps,
 505   ExceptionHandlerTable* handler_table,
 506   ImplicitExceptionTable* nul_chk_table,
 507   AbstractCompiler* compiler,
 508   int comp_level
 509 )
 510 {
 511   assert(debug_info->oop_recorder() == code_buffer->oop_recorder(), "shared OR");
 512   // create nmethod
 513   nmethod* nm = NULL;
 514   { MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
 515     int nmethod_size =
 516       allocation_size(code_buffer, sizeof(nmethod))
 517       + adjust_pcs_size(debug_info->pcs_size())
 518       + round_to(dependencies->size_in_bytes() , oopSize)
 519       + round_to(handler_table->size_in_bytes(), oopSize)
 520       + round_to(nul_chk_table->size_in_bytes(), oopSize)
 521       + round_to(debug_info->data_size()       , oopSize);
 522     nm = new (nmethod_size)
 523       nmethod(method(), nmethod_size, compile_id, entry_bci, offsets,
 524               orig_pc_offset, debug_info, dependencies, code_buffer, frame_size,
 525               oop_maps,
 526               handler_table,
 527               nul_chk_table,
 528               compiler,
 529               comp_level);
 530     if (nm != NULL) {
 531       // To make dependency checking during class loading fast, record
 532       // the nmethod dependencies in the classes it is dependent on.
 533       // This allows the dependency checking code to simply walk the
 534       // class hierarchy above the loaded class, checking only nmethods
 535       // which are dependent on those classes.  The slow way is to
 536       // check every nmethod for dependencies which makes it linear in
 537       // the number of methods compiled.  For applications with a lot
 538       // classes the slow way is too slow.
 539       for (Dependencies::DepStream deps(nm); deps.next(); ) {
 540         klassOop klass = deps.context_type();
 541         if (klass == NULL)  continue;  // ignore things like evol_method
 542 
 543         // record this nmethod as dependent on this klass
 544         instanceKlass::cast(klass)->add_dependent_nmethod(nm);
 545       }
 546     }
 547     NOT_PRODUCT(if (nm != NULL)  nmethod_stats.note_nmethod(nm));
 548     if (PrintAssembly && nm != NULL)
 549       Disassembler::decode(nm);
 550   }
 551 
 552   // verify nmethod
 553   debug_only(if (nm) nm->verify();) // might block
 554 
 555   if (nm != NULL) {
 556     nm->log_new_nmethod();
 557   }
 558 
 559   // done
 560   return nm;
 561 }
 562 
 563 
 564 // For native wrappers
 565 nmethod::nmethod(
 566   methodOop method,
 567   int nmethod_size,
 568   CodeOffsets* offsets,
 569   CodeBuffer* code_buffer,
 570   int frame_size,
 571   ByteSize basic_lock_owner_sp_offset,
 572   ByteSize basic_lock_sp_offset,
 573   OopMapSet* oop_maps )
 574   : CodeBlob("native nmethod", code_buffer, sizeof(nmethod),
 575              nmethod_size, offsets->value(CodeOffsets::Frame_Complete), frame_size, oop_maps),
 576   _compiled_synchronized_native_basic_lock_owner_sp_offset(basic_lock_owner_sp_offset),
 577   _compiled_synchronized_native_basic_lock_sp_offset(basic_lock_sp_offset)
 578 {
 579   {
 580     debug_only(No_Safepoint_Verifier nsv;)
 581     assert_locked_or_safepoint(CodeCache_lock);
 582 
 583     NOT_PRODUCT(_has_debug_info = false);
 584     _oops_do_mark_link       = NULL;
 585     _method                  = method;
 586     _entry_bci               = InvocationEntryBci;
 587     _osr_link                = NULL;
 588     _scavenge_root_link      = NULL;
 589     _scavenge_root_state     = 0;
 590     _saved_nmethod_link      = NULL;
 591     _compiler                = NULL;
 592     // We have no exception handler or deopt handler make the
 593     // values something that will never match a pc like the nmethod vtable entry
 594     _exception_offset        = 0;
 595     _deoptimize_offset       = 0;
 596     _deoptimize_mh_offset    = 0;
 597     _orig_pc_offset          = 0;
 598 #ifdef HAVE_DTRACE_H
 599     _trap_offset             = 0;
 600 #endif // def HAVE_DTRACE_H
 601     _stub_offset             = data_offset();
 602     _consts_offset           = data_offset();
 603     _oops_offset             = data_offset();
 604     _scopes_data_offset      = _oops_offset          + round_to(code_buffer->total_oop_size(), oopSize);
 605     _scopes_pcs_offset       = _scopes_data_offset;
 606     _dependencies_offset     = _scopes_pcs_offset;
 607     _handler_table_offset    = _dependencies_offset;
 608     _nul_chk_table_offset    = _handler_table_offset;
 609     _nmethod_end_offset      = _nul_chk_table_offset;
 610     _compile_id              = 0;  // default
 611     _comp_level              = CompLevel_none;
 612     _entry_point             = instructions_begin();
 613     _verified_entry_point    = instructions_begin() + offsets->value(CodeOffsets::Verified_Entry);
 614     _osr_entry_point         = NULL;
 615     _exception_cache         = NULL;
 616     _pc_desc_cache.reset_to(NULL);
 617 
 618     flags.clear();
 619     flags.state              = alive;
 620     _markedForDeoptimization = 0;
 621 
 622     _lock_count = 0;
 623     _stack_traversal_mark    = 0;
 624 
 625     code_buffer->copy_oops_to(this);
 626     debug_only(verify_scavenge_root_oops());
 627     CodeCache::commit(this);
 628     VTune::create_nmethod(this);
 629   }
 630 
 631   if (PrintNativeNMethods || PrintDebugInfo || PrintRelocations || PrintDependencies) {
 632     ttyLocker ttyl;  // keep the following output all in one block
 633     // This output goes directly to the tty, not the compiler log.
 634     // To enable tools to match it up with the compilation activity,
 635     // be sure to tag this tty output with the compile ID.
 636     if (xtty != NULL) {
 637       xtty->begin_head("print_native_nmethod");
 638       xtty->method(_method);
 639       xtty->stamp();
 640       xtty->end_head(" address='" INTPTR_FORMAT "'", (intptr_t) this);
 641     }
 642     // print the header part first
 643     print();
 644     // then print the requested information
 645     if (PrintNativeNMethods) {
 646       print_code();
 647       oop_maps->print();
 648     }
 649     if (PrintRelocations) {
 650       print_relocations();
 651     }
 652     if (xtty != NULL) {
 653       xtty->tail("print_native_nmethod");
 654     }
 655   }
 656   Events::log("Create nmethod " INTPTR_FORMAT, this);
 657 }
 658 
 659 // For dtrace wrappers
 660 #ifdef HAVE_DTRACE_H
 661 nmethod::nmethod(
 662   methodOop method,
 663   int nmethod_size,
 664   CodeOffsets* offsets,
 665   CodeBuffer* code_buffer,
 666   int frame_size)
 667   : CodeBlob("dtrace nmethod", code_buffer, sizeof(nmethod),
 668              nmethod_size, offsets->value(CodeOffsets::Frame_Complete), frame_size, NULL),
 669   _compiled_synchronized_native_basic_lock_owner_sp_offset(in_ByteSize(-1)),
 670   _compiled_synchronized_native_basic_lock_sp_offset(in_ByteSize(-1))
 671 {
 672   {
 673     debug_only(No_Safepoint_Verifier nsv;)
 674     assert_locked_or_safepoint(CodeCache_lock);
 675 
 676     NOT_PRODUCT(_has_debug_info = false);
 677     _oops_do_mark_link       = NULL;
 678     _method                  = method;
 679     _entry_bci               = InvocationEntryBci;
 680     _osr_link                = NULL;
 681     _scavenge_root_link      = NULL;
 682     _scavenge_root_state     = 0;
 683     _compiler                = NULL;
 684     // We have no exception handler or deopt handler make the
 685     // values something that will never match a pc like the nmethod vtable entry
 686     _exception_offset        = 0;
 687     _deoptimize_offset       = 0;
 688     _deoptimize_mh_offset    = 0;
 689     _unwind_handler_offset   = -1;
 690     _trap_offset             = offsets->value(CodeOffsets::Dtrace_trap);
 691     _orig_pc_offset          = 0;
 692     _stub_offset             = data_offset();
 693     _consts_offset           = data_offset();
 694     _oops_offset             = data_offset();
 695     _scopes_data_offset      = _oops_offset          + round_to(code_buffer->total_oop_size(), oopSize);
 696     _scopes_pcs_offset       = _scopes_data_offset;
 697     _dependencies_offset     = _scopes_pcs_offset;
 698     _handler_table_offset    = _dependencies_offset;
 699     _nul_chk_table_offset    = _handler_table_offset;
 700     _nmethod_end_offset      = _nul_chk_table_offset;
 701     _compile_id              = 0;  // default
 702     _comp_level              = CompLevel_none;
 703     _entry_point             = instructions_begin();
 704     _verified_entry_point    = instructions_begin() + offsets->value(CodeOffsets::Verified_Entry);
 705     _osr_entry_point         = NULL;
 706     _exception_cache         = NULL;
 707     _pc_desc_cache.reset_to(NULL);
 708 
 709     flags.clear();
 710     flags.state              = alive;
 711     _markedForDeoptimization = 0;
 712 
 713     _lock_count = 0;
 714     _stack_traversal_mark    = 0;
 715 
 716     code_buffer->copy_oops_to(this);
 717     debug_only(verify_scavenge_root_oops());
 718     CodeCache::commit(this);
 719     VTune::create_nmethod(this);
 720   }
 721 
 722   if (PrintNMethods || PrintDebugInfo || PrintRelocations || PrintDependencies) {
 723     ttyLocker ttyl;  // keep the following output all in one block
 724     // This output goes directly to the tty, not the compiler log.
 725     // To enable tools to match it up with the compilation activity,
 726     // be sure to tag this tty output with the compile ID.
 727     if (xtty != NULL) {
 728       xtty->begin_head("print_dtrace_nmethod");
 729       xtty->method(_method);
 730       xtty->stamp();
 731       xtty->end_head(" address='" INTPTR_FORMAT "'", (intptr_t) this);
 732     }
 733     // print the header part first
 734     print();
 735     // then print the requested information
 736     if (PrintNMethods) {
 737       print_code();
 738     }
 739     if (PrintRelocations) {
 740       print_relocations();
 741     }
 742     if (xtty != NULL) {
 743       xtty->tail("print_dtrace_nmethod");
 744     }
 745   }
 746   Events::log("Create nmethod " INTPTR_FORMAT, this);
 747 }
 748 #endif // def HAVE_DTRACE_H
 749 
 750 void* nmethod::operator new(size_t size, int nmethod_size) {
 751   // Always leave some room in the CodeCache for I2C/C2I adapters
 752   if (CodeCache::unallocated_capacity() < CodeCacheMinimumFreeSpace) return NULL;
 753   return CodeCache::allocate(nmethod_size);
 754 }
 755 
 756 
 757 nmethod::nmethod(
 758   methodOop method,
 759   int nmethod_size,
 760   int compile_id,
 761   int entry_bci,
 762   CodeOffsets* offsets,
 763   int orig_pc_offset,
 764   DebugInformationRecorder* debug_info,
 765   Dependencies* dependencies,
 766   CodeBuffer *code_buffer,
 767   int frame_size,
 768   OopMapSet* oop_maps,
 769   ExceptionHandlerTable* handler_table,
 770   ImplicitExceptionTable* nul_chk_table,
 771   AbstractCompiler* compiler,
 772   int comp_level
 773   )
 774   : CodeBlob("nmethod", code_buffer, sizeof(nmethod),
 775              nmethod_size, offsets->value(CodeOffsets::Frame_Complete), frame_size, oop_maps),
 776   _compiled_synchronized_native_basic_lock_owner_sp_offset(in_ByteSize(-1)),
 777   _compiled_synchronized_native_basic_lock_sp_offset(in_ByteSize(-1))
 778 {
 779   assert(debug_info->oop_recorder() == code_buffer->oop_recorder(), "shared OR");
 780   {
 781     debug_only(No_Safepoint_Verifier nsv;)
 782     assert_locked_or_safepoint(CodeCache_lock);
 783 
 784     NOT_PRODUCT(_has_debug_info = false);
 785     _oops_do_mark_link       = NULL;
 786     _method                  = method;
 787     _compile_id              = compile_id;
 788     _comp_level              = comp_level;
 789     _entry_bci               = entry_bci;
 790     _osr_link                = NULL;
 791     _scavenge_root_link      = NULL;
 792     _scavenge_root_state     = 0;
 793     _compiler                = compiler;
 794     _orig_pc_offset          = orig_pc_offset;
 795 #ifdef HAVE_DTRACE_H
 796     _trap_offset             = 0;
 797 #endif // def HAVE_DTRACE_H
 798     _stub_offset             = instructions_offset() + code_buffer->total_offset_of(code_buffer->stubs()->start());
 799 
 800     // Exception handler and deopt handler are in the stub section
 801     _exception_offset        = _stub_offset + offsets->value(CodeOffsets::Exceptions);
 802     _deoptimize_offset       = _stub_offset + offsets->value(CodeOffsets::Deopt);
 803     _deoptimize_mh_offset    = _stub_offset + offsets->value(CodeOffsets::DeoptMH);
 804     if (offsets->value(CodeOffsets::UnwindHandler) != -1) {
 805       _unwind_handler_offset   = instructions_offset() + offsets->value(CodeOffsets::UnwindHandler);
 806     } else {
 807       _unwind_handler_offset   = -1;
 808     }
 809     _consts_offset           = instructions_offset() + code_buffer->total_offset_of(code_buffer->consts()->start());
 810     _oops_offset             = data_offset();
 811     _scopes_data_offset      = _oops_offset          + round_to(code_buffer->total_oop_size (), oopSize);
 812     _scopes_pcs_offset       = _scopes_data_offset   + round_to(debug_info->data_size       (), oopSize);
 813     _dependencies_offset     = _scopes_pcs_offset    + adjust_pcs_size(debug_info->pcs_size());
 814     _handler_table_offset    = _dependencies_offset  + round_to(dependencies->size_in_bytes (), oopSize);
 815     _nul_chk_table_offset    = _handler_table_offset + round_to(handler_table->size_in_bytes(), oopSize);
 816     _nmethod_end_offset      = _nul_chk_table_offset + round_to(nul_chk_table->size_in_bytes(), oopSize);
 817 
 818     _entry_point             = instructions_begin();
 819     _verified_entry_point    = instructions_begin() + offsets->value(CodeOffsets::Verified_Entry);
 820     _osr_entry_point         = instructions_begin() + offsets->value(CodeOffsets::OSR_Entry);
 821     _exception_cache         = NULL;
 822     _pc_desc_cache.reset_to(scopes_pcs_begin());
 823 
 824     flags.clear();
 825     flags.state              = alive;
 826     _markedForDeoptimization = 0;
 827 
 828     _unload_reported         = false;           // jvmti state
 829 
 830     _lock_count = 0;
 831     _stack_traversal_mark    = 0;
 832 
 833     // Copy contents of ScopeDescRecorder to nmethod
 834     code_buffer->copy_oops_to(this);
 835     debug_info->copy_to(this);
 836     dependencies->copy_to(this);
 837     if (ScavengeRootsInCode && detect_scavenge_root_oops()) {
 838       CodeCache::add_scavenge_root_nmethod(this);
 839     }
 840     debug_only(verify_scavenge_root_oops());
 841 
 842     CodeCache::commit(this);
 843 
 844     VTune::create_nmethod(this);
 845 
 846     // Copy contents of ExceptionHandlerTable to nmethod
 847     handler_table->copy_to(this);
 848     nul_chk_table->copy_to(this);
 849 
 850     // we use the information of entry points to find out if a method is
 851     // static or non static
 852     assert(compiler->is_c2() ||
 853            _method->is_static() == (entry_point() == _verified_entry_point),
 854            " entry points must be same for static methods and vice versa");
 855   }
 856 
 857   bool printnmethods = PrintNMethods
 858     || CompilerOracle::should_print(_method)
 859     || CompilerOracle::has_option_string(_method, "PrintNMethods");
 860   if (printnmethods || PrintDebugInfo || PrintRelocations || PrintDependencies || PrintExceptionHandlers) {
 861     print_nmethod(printnmethods);
 862   }
 863 
 864   // Note: Do not verify in here as the CodeCache_lock is
 865   //       taken which would conflict with the CompiledIC_lock
 866   //       which taken during the verification of call sites.
 867   //       (was bug - gri 10/25/99)
 868 
 869   Events::log("Create nmethod " INTPTR_FORMAT, this);
 870 }
 871 
 872 
 873 // Print a short set of xml attributes to identify this nmethod.  The
 874 // output should be embedded in some other element.
 875 void nmethod::log_identity(xmlStream* log) const {
 876   log->print(" compile_id='%d'", compile_id());
 877   const char* nm_kind = compile_kind();
 878   if (nm_kind != NULL)  log->print(" compile_kind='%s'", nm_kind);
 879   if (compiler() != NULL) {
 880     log->print(" compiler='%s'", compiler()->name());
 881   }
 882 #ifdef TIERED
 883   log->print(" level='%d'", comp_level());
 884 #endif // TIERED
 885 }
 886 
 887 
 888 #define LOG_OFFSET(log, name)                    \
 889   if ((intptr_t)name##_end() - (intptr_t)name##_begin()) \
 890     log->print(" " XSTR(name) "_offset='%d'"    , \
 891                (intptr_t)name##_begin() - (intptr_t)this)
 892 
 893 
 894 void nmethod::log_new_nmethod() const {
 895   if (LogCompilation && xtty != NULL) {
 896     ttyLocker ttyl;
 897     HandleMark hm;
 898     xtty->begin_elem("nmethod");
 899     log_identity(xtty);
 900     xtty->print(" entry='" INTPTR_FORMAT "' size='%d'",
 901                 instructions_begin(), size());
 902     xtty->print(" address='" INTPTR_FORMAT "'", (intptr_t) this);
 903 
 904     LOG_OFFSET(xtty, relocation);
 905     LOG_OFFSET(xtty, code);
 906     LOG_OFFSET(xtty, stub);
 907     LOG_OFFSET(xtty, consts);
 908     LOG_OFFSET(xtty, scopes_data);
 909     LOG_OFFSET(xtty, scopes_pcs);
 910     LOG_OFFSET(xtty, dependencies);
 911     LOG_OFFSET(xtty, handler_table);
 912     LOG_OFFSET(xtty, nul_chk_table);
 913     LOG_OFFSET(xtty, oops);
 914 
 915     xtty->method(method());
 916     xtty->stamp();
 917     xtty->end_elem();
 918   }
 919 }
 920 
 921 #undef LOG_OFFSET
 922 
 923 
 924 // Print out more verbose output usually for a newly created nmethod.
 925 void nmethod::print_on(outputStream* st, const char* title) const {
 926   if (st != NULL) {
 927     ttyLocker ttyl;
 928     // Print a little tag line that looks like +PrintCompilation output:
 929     int tlen = (int) strlen(title);
 930     bool do_nl = false;
 931     if (tlen > 0 && title[tlen-1] == '\n') { tlen--; do_nl = true; }
 932     st->print("%3d%c  %.*s",
 933               compile_id(),
 934               is_osr_method() ? '%' :
 935               method() != NULL &&
 936               is_native_method() ? 'n' : ' ',
 937               tlen, title);
 938 #ifdef TIERED
 939     st->print(" (%d) ", comp_level());
 940 #endif // TIERED
 941     if (WizardMode) st->print(" (" INTPTR_FORMAT ")", this);
 942     if (Universe::heap()->is_gc_active() && method() != NULL) {
 943       st->print("(method)");
 944     } else if (method() != NULL) {
 945         method()->print_short_name(st);
 946       if (is_osr_method())
 947         st->print(" @ %d", osr_entry_bci());
 948       if (method()->code_size() > 0)
 949         st->print(" (%d bytes)", method()->code_size());
 950     }
 951 
 952     if (do_nl)  st->cr();
 953   }
 954 }
 955 
 956 
 957 void nmethod::print_nmethod(bool printmethod) {
 958   ttyLocker ttyl;  // keep the following output all in one block
 959   if (xtty != NULL) {
 960     xtty->begin_head("print_nmethod");
 961     xtty->stamp();
 962     xtty->end_head();
 963   }
 964   // print the header part first
 965   print();
 966   // then print the requested information
 967   if (printmethod) {
 968     print_code();
 969     print_pcs();
 970     oop_maps()->print();
 971   }
 972   if (PrintDebugInfo) {
 973     print_scopes();
 974   }
 975   if (PrintRelocations) {
 976     print_relocations();
 977   }
 978   if (PrintDependencies) {
 979     print_dependencies();
 980   }
 981   if (PrintExceptionHandlers) {
 982     print_handler_table();
 983     print_nul_chk_table();
 984   }
 985   if (xtty != NULL) {
 986     xtty->tail("print_nmethod");
 987   }
 988 }
 989 
 990 
 991 void nmethod::set_version(int v) {
 992   flags.version = v;
 993 }
 994 
 995 
 996 // Promote one word from an assembly-time handle to a live embedded oop.
 997 inline void nmethod::initialize_immediate_oop(oop* dest, jobject handle) {
 998   if (handle == NULL ||
 999       // As a special case, IC oops are initialized to 1 or -1.
1000       handle == (jobject) Universe::non_oop_word()) {
1001     (*dest) = (oop) handle;
1002   } else {
1003     (*dest) = JNIHandles::resolve_non_null(handle);
1004   }
1005 }
1006 
1007 
1008 void nmethod::copy_oops(GrowableArray<jobject>* array) {
1009   //assert(oops_size() == 0, "do this handshake just once, please");
1010   int length = array->length();
1011   assert((address)(oops_begin() + length) <= data_end(), "oops big enough");
1012   oop* dest = oops_begin();
1013   for (int index = 0 ; index < length; index++) {
1014     initialize_immediate_oop(&dest[index], array->at(index));
1015   }
1016 
1017   // Now we can fix up all the oops in the code.  We need to do this
1018   // in the code because the assembler uses jobjects as placeholders.
1019   // The code and relocations have already been initialized by the
1020   // CodeBlob constructor, so it is valid even at this early point to
1021   // iterate over relocations and patch the code.
1022   fix_oop_relocations(NULL, NULL, /*initialize_immediates=*/ true);
1023 }
1024 
1025 
1026 bool nmethod::is_at_poll_return(address pc) {
1027   RelocIterator iter(this, pc, pc+1);
1028   while (iter.next()) {
1029     if (iter.type() == relocInfo::poll_return_type)
1030       return true;
1031   }
1032   return false;
1033 }
1034 
1035 
1036 bool nmethod::is_at_poll_or_poll_return(address pc) {
1037   RelocIterator iter(this, pc, pc+1);
1038   while (iter.next()) {
1039     relocInfo::relocType t = iter.type();
1040     if (t == relocInfo::poll_return_type || t == relocInfo::poll_type)
1041       return true;
1042   }
1043   return false;
1044 }
1045 
1046 
1047 void nmethod::fix_oop_relocations(address begin, address end, bool initialize_immediates) {
1048   // re-patch all oop-bearing instructions, just in case some oops moved
1049   RelocIterator iter(this, begin, end);
1050   while (iter.next()) {
1051     if (iter.type() == relocInfo::oop_type) {
1052       oop_Relocation* reloc = iter.oop_reloc();
1053       if (initialize_immediates && reloc->oop_is_immediate()) {
1054         oop* dest = reloc->oop_addr();
1055         initialize_immediate_oop(dest, (jobject) *dest);
1056       }
1057       // Refresh the oop-related bits of this instruction.
1058       reloc->fix_oop_relocation();
1059     }
1060 
1061     // There must not be any interfering patches or breakpoints.
1062     assert(!(iter.type() == relocInfo::breakpoint_type
1063              && iter.breakpoint_reloc()->active()),
1064            "no active breakpoint");
1065   }
1066 }
1067 
1068 
1069 ScopeDesc* nmethod::scope_desc_at(address pc) {
1070   PcDesc* pd = pc_desc_at(pc);
1071   guarantee(pd != NULL, "scope must be present");
1072   return new ScopeDesc(this, pd->scope_decode_offset(),
1073                        pd->obj_decode_offset(), pd->should_reexecute(),
1074                        pd->return_oop());
1075 }
1076 
1077 
1078 void nmethod::clear_inline_caches() {
1079   assert(SafepointSynchronize::is_at_safepoint(), "cleaning of IC's only allowed at safepoint");
1080   if (is_zombie()) {
1081     return;
1082   }
1083 
1084   RelocIterator iter(this);
1085   while (iter.next()) {
1086     iter.reloc()->clear_inline_cache();
1087   }
1088 }
1089 
1090 
1091 void nmethod::cleanup_inline_caches() {
1092 
1093   assert_locked_or_safepoint(CompiledIC_lock);
1094 
1095   // If the method is not entrant or zombie then a JMP is plastered over the
1096   // first few bytes.  If an oop in the old code was there, that oop
1097   // should not get GC'd.  Skip the first few bytes of oops on
1098   // not-entrant methods.
1099   address low_boundary = verified_entry_point();
1100   if (!is_in_use()) {
1101     low_boundary += NativeJump::instruction_size;
1102     // %%% Note:  On SPARC we patch only a 4-byte trap, not a full NativeJump.
1103     // This means that the low_boundary is going to be a little too high.
1104     // This shouldn't matter, since oops of non-entrant methods are never used.
1105     // In fact, why are we bothering to look at oops in a non-entrant method??
1106   }
1107 
1108   // Find all calls in an nmethod, and clear the ones that points to zombie methods
1109   ResourceMark rm;
1110   RelocIterator iter(this, low_boundary);
1111   while(iter.next()) {
1112     switch(iter.type()) {
1113       case relocInfo::virtual_call_type:
1114       case relocInfo::opt_virtual_call_type: {
1115         CompiledIC *ic = CompiledIC_at(iter.reloc());
1116         // Ok, to lookup references to zombies here
1117         CodeBlob *cb = CodeCache::find_blob_unsafe(ic->ic_destination());
1118         if( cb != NULL && cb->is_nmethod() ) {
1119           nmethod* nm = (nmethod*)cb;
1120           // Clean inline caches pointing to both zombie and not_entrant methods
1121           if (!nm->is_in_use() || (nm->method()->code() != nm)) ic->set_to_clean();
1122         }
1123         break;
1124       }
1125       case relocInfo::static_call_type: {
1126         CompiledStaticCall *csc = compiledStaticCall_at(iter.reloc());
1127         CodeBlob *cb = CodeCache::find_blob_unsafe(csc->destination());
1128         if( cb != NULL && cb->is_nmethod() ) {
1129           nmethod* nm = (nmethod*)cb;
1130           // Clean inline caches pointing to both zombie and not_entrant methods
1131           if (!nm->is_in_use() || (nm->method()->code() != nm)) csc->set_to_clean();
1132         }
1133         break;
1134       }
1135     }
1136   }
1137 }
1138 
1139 // This is a private interface with the sweeper.
1140 void nmethod::mark_as_seen_on_stack() {
1141   assert(is_not_entrant(), "must be a non-entrant method");
1142   set_stack_traversal_mark(NMethodSweeper::traversal_count());
1143 }
1144 
1145 // Tell if a non-entrant method can be converted to a zombie (i.e., there is no activations on the stack)
1146 bool nmethod::can_not_entrant_be_converted() {
1147   assert(is_not_entrant(), "must be a non-entrant method");
1148 
1149   // Since the nmethod sweeper only does partial sweep the sweeper's traversal
1150   // count can be greater than the stack traversal count before it hits the
1151   // nmethod for the second time.
1152   return stack_traversal_mark()+1 < NMethodSweeper::traversal_count();
1153 }
1154 
1155 void nmethod::inc_decompile_count() {
1156   // Could be gated by ProfileTraps, but do not bother...
1157   methodOop m = method();
1158   if (m == NULL)  return;
1159   methodDataOop mdo = m->method_data();
1160   if (mdo == NULL)  return;
1161   // There is a benign race here.  See comments in methodDataOop.hpp.
1162   mdo->inc_decompile_count();
1163 }
1164 
1165 void nmethod::make_unloaded(BoolObjectClosure* is_alive, oop cause) {
1166 
1167   post_compiled_method_unload();
1168 
1169   // Since this nmethod is being unloaded, make sure that dependencies
1170   // recorded in instanceKlasses get flushed and pass non-NULL closure to
1171   // indicate that this work is being done during a GC.
1172   assert(Universe::heap()->is_gc_active(), "should only be called during gc");
1173   assert(is_alive != NULL, "Should be non-NULL");
1174   // A non-NULL is_alive closure indicates that this is being called during GC.
1175   flush_dependencies(is_alive);
1176 
1177   // Break cycle between nmethod & method
1178   if (TraceClassUnloading && WizardMode) {
1179     tty->print_cr("[Class unloading: Making nmethod " INTPTR_FORMAT
1180                   " unloadable], methodOop(" INTPTR_FORMAT
1181                   "), cause(" INTPTR_FORMAT ")",
1182                   this, (address)_method, (address)cause);
1183     if (!Universe::heap()->is_gc_active())
1184       cause->klass()->print();
1185   }
1186   // Unlink the osr method, so we do not look this up again
1187   if (is_osr_method()) {
1188     invalidate_osr_method();
1189   }
1190   // If _method is already NULL the methodOop is about to be unloaded,
1191   // so we don't have to break the cycle. Note that it is possible to
1192   // have the methodOop live here, in case we unload the nmethod because
1193   // it is pointing to some oop (other than the methodOop) being unloaded.
1194   if (_method != NULL) {
1195     // OSR methods point to the methodOop, but the methodOop does not
1196     // point back!
1197     if (_method->code() == this) {
1198       _method->clear_code(); // Break a cycle
1199     }
1200     _method = NULL;            // Clear the method of this dead nmethod
1201   }
1202   // Make the class unloaded - i.e., change state and notify sweeper
1203   assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
1204   if (is_in_use()) {
1205     // Transitioning directly from live to unloaded -- so
1206     // we need to force a cache clean-up; remember this
1207     // for later on.
1208     CodeCache::set_needs_cache_clean(true);
1209   }
1210   flags.state = unloaded;
1211 
1212   // Log the unloading.
1213   log_state_change();
1214 
1215   // The methodOop is gone at this point
1216   assert(_method == NULL, "Tautology");
1217 
1218   set_osr_link(NULL);
1219   //set_scavenge_root_link(NULL); // done by prune_scavenge_root_nmethods
1220   NMethodSweeper::notify(this);
1221 }
1222 
1223 void nmethod::invalidate_osr_method() {
1224   assert(_entry_bci != InvocationEntryBci, "wrong kind of nmethod");
1225   // Remove from list of active nmethods
1226   if (method() != NULL)
1227     instanceKlass::cast(method()->method_holder())->remove_osr_nmethod(this);
1228   // Set entry as invalid
1229   _entry_bci = InvalidOSREntryBci;
1230 }
1231 
1232 void nmethod::log_state_change() const {
1233   if (LogCompilation) {
1234     if (xtty != NULL) {
1235       ttyLocker ttyl;  // keep the following output all in one block
1236       if (flags.state == unloaded) {
1237         xtty->begin_elem("make_unloaded thread='" UINTX_FORMAT "'",
1238                          os::current_thread_id());
1239       } else {
1240         xtty->begin_elem("make_not_entrant thread='" UINTX_FORMAT "'%s",
1241                          os::current_thread_id(),
1242                          (flags.state == zombie ? " zombie='1'" : ""));
1243       }
1244       log_identity(xtty);
1245       xtty->stamp();
1246       xtty->end_elem();
1247     }
1248   }
1249   if (PrintCompilation && flags.state != unloaded) {
1250     print_on(tty, flags.state == zombie ? "made zombie " : "made not entrant ");
1251     tty->cr();
1252   }
1253 }
1254 
1255 // Common functionality for both make_not_entrant and make_zombie
1256 bool nmethod::make_not_entrant_or_zombie(unsigned int state) {
1257   assert(state == zombie || state == not_entrant, "must be zombie or not_entrant");
1258 
1259   bool was_alive = false;
1260 
1261   // Make sure the nmethod is not flushed in case of a safepoint in code below.
1262   nmethodLocker nml(this);
1263 
1264   {
1265     // If the method is already zombie there is nothing to do
1266     if (is_zombie()) {
1267       return false;
1268     }
1269 
1270     // invalidate osr nmethod before acquiring the patching lock since
1271     // they both acquire leaf locks and we don't want a deadlock.
1272     // This logic is equivalent to the logic below for patching the
1273     // verified entry point of regular methods.
1274     if (is_osr_method()) {
1275       // this effectively makes the osr nmethod not entrant
1276       invalidate_osr_method();
1277     }
1278 
1279     // Enter critical section.  Does not block for safepoint.
1280     MutexLockerEx pl(Patching_lock, Mutex::_no_safepoint_check_flag);
1281 
1282     if (flags.state == state) {
1283       // another thread already performed this transition so nothing
1284       // to do, but return false to indicate this.
1285       return false;
1286     }
1287 
1288     // The caller can be calling the method statically or through an inline
1289     // cache call.
1290     if (!is_osr_method() && !is_not_entrant()) {
1291       NativeJump::patch_verified_entry(entry_point(), verified_entry_point(),
1292                   SharedRuntime::get_handle_wrong_method_stub());
1293       assert (NativeJump::instruction_size == nmethod::_zombie_instruction_size, "");
1294     }
1295 
1296     was_alive = is_in_use(); // Read state under lock
1297 
1298     // Change state
1299     flags.state = state;
1300 
1301     // Log the transition once
1302     log_state_change();
1303 
1304   } // leave critical region under Patching_lock
1305 
1306   // When the nmethod becomes zombie it is no longer alive so the
1307   // dependencies must be flushed.  nmethods in the not_entrant
1308   // state will be flushed later when the transition to zombie
1309   // happens or they get unloaded.
1310   if (state == zombie) {
1311     MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
1312     flush_dependencies(NULL);
1313   } else {
1314     assert(state == not_entrant, "other cases may need to be handled differently");
1315   }
1316 
1317   if (state == not_entrant) {
1318     Events::log("Make nmethod not entrant " INTPTR_FORMAT, this);
1319   } else {
1320     Events::log("Make nmethod zombie " INTPTR_FORMAT, this);
1321   }
1322 
1323   if (TraceCreateZombies) {
1324     tty->print_cr("nmethod <" INTPTR_FORMAT "> code made %s", this, (state == not_entrant) ? "not entrant" : "zombie");
1325   }
1326 
1327   // Make sweeper aware that there is a zombie method that needs to be removed
1328   NMethodSweeper::notify(this);
1329 
1330   // not_entrant only stuff
1331   if (state == not_entrant) {
1332     mark_as_seen_on_stack();
1333   }
1334 
1335   if (was_alive) {
1336     // It's a true state change, so mark the method as decompiled.
1337     // Do it only for transition from alive.
1338     inc_decompile_count();
1339   }
1340 
1341   // zombie only - if a JVMTI agent has enabled the CompiledMethodUnload event
1342   // and it hasn't already been reported for this nmethod then report it now.
1343   // (the event may have been reported earilier if the GC marked it for unloading).
1344   if (state == zombie) {
1345     post_compiled_method_unload();
1346   }
1347 
1348 
1349   // Zombie only stuff
1350   if (state == zombie) {
1351     VTune::delete_nmethod(this);
1352   }
1353 
1354   // Check whether method got unloaded at a safepoint before this,
1355   // if so we can skip the flushing steps below
1356   if (method() == NULL) return true;
1357 
1358   // Remove nmethod from method.
1359   // We need to check if both the _code and _from_compiled_code_entry_point
1360   // refer to this nmethod because there is a race in setting these two fields
1361   // in methodOop as seen in bugid 4947125.
1362   // If the vep() points to the zombie nmethod, the memory for the nmethod
1363   // could be flushed and the compiler and vtable stubs could still call
1364   // through it.
1365   if (method()->code() == this ||
1366       method()->from_compiled_entry() == verified_entry_point()) {
1367     HandleMark hm;
1368     method()->clear_code();
1369   }
1370 
1371   return true;
1372 }
1373 
1374 void nmethod::flush() {
1375   // Note that there are no valid oops in the nmethod anymore.
1376   assert(is_zombie() || (is_osr_method() && is_unloaded()), "must be a zombie method");
1377   assert(is_marked_for_reclamation() || (is_osr_method() && is_unloaded()), "must be marked for reclamation");
1378 
1379   assert (!is_locked_by_vm(), "locked methods shouldn't be flushed");
1380   assert_locked_or_safepoint(CodeCache_lock);
1381 
1382   // completely deallocate this method
1383   EventMark m("flushing nmethod " INTPTR_FORMAT " %s", this, "");
1384   if (PrintMethodFlushing) {
1385     tty->print_cr("*flushing nmethod %3d/" INTPTR_FORMAT ". Live blobs:" UINT32_FORMAT "/Free CodeCache:" SIZE_FORMAT "Kb",
1386         _compile_id, this, CodeCache::nof_blobs(), CodeCache::unallocated_capacity()/1024);
1387   }
1388 
1389   // We need to deallocate any ExceptionCache data.
1390   // Note that we do not need to grab the nmethod lock for this, it
1391   // better be thread safe if we're disposing of it!
1392   ExceptionCache* ec = exception_cache();
1393   set_exception_cache(NULL);
1394   while(ec != NULL) {
1395     ExceptionCache* next = ec->next();
1396     delete ec;
1397     ec = next;
1398   }
1399 
1400   if (on_scavenge_root_list()) {
1401     CodeCache::drop_scavenge_root_nmethod(this);
1402   }
1403 
1404   if (is_speculatively_disconnected()) {
1405     CodeCache::remove_saved_code(this);
1406   }
1407 
1408   ((CodeBlob*)(this))->flush();
1409 
1410   CodeCache::free(this);
1411 }
1412 
1413 
1414 //
1415 // Notify all classes this nmethod is dependent on that it is no
1416 // longer dependent. This should only be called in two situations.
1417 // First, when a nmethod transitions to a zombie all dependents need
1418 // to be clear.  Since zombification happens at a safepoint there's no
1419 // synchronization issues.  The second place is a little more tricky.
1420 // During phase 1 of mark sweep class unloading may happen and as a
1421 // result some nmethods may get unloaded.  In this case the flushing
1422 // of dependencies must happen during phase 1 since after GC any
1423 // dependencies in the unloaded nmethod won't be updated, so
1424 // traversing the dependency information in unsafe.  In that case this
1425 // function is called with a non-NULL argument and this function only
1426 // notifies instanceKlasses that are reachable
1427 
1428 void nmethod::flush_dependencies(BoolObjectClosure* is_alive) {
1429   assert_locked_or_safepoint(CodeCache_lock);
1430   assert(Universe::heap()->is_gc_active() == (is_alive != NULL),
1431   "is_alive is non-NULL if and only if we are called during GC");
1432   if (!has_flushed_dependencies()) {
1433     set_has_flushed_dependencies();
1434     for (Dependencies::DepStream deps(this); deps.next(); ) {
1435       klassOop klass = deps.context_type();
1436       if (klass == NULL)  continue;  // ignore things like evol_method
1437 
1438       // During GC the is_alive closure is non-NULL, and is used to
1439       // determine liveness of dependees that need to be updated.
1440       if (is_alive == NULL || is_alive->do_object_b(klass)) {
1441         instanceKlass::cast(klass)->remove_dependent_nmethod(this);
1442       }
1443     }
1444   }
1445 }
1446 
1447 
1448 // If this oop is not live, the nmethod can be unloaded.
1449 bool nmethod::can_unload(BoolObjectClosure* is_alive,
1450                          OopClosure* keep_alive,
1451                          oop* root, bool unloading_occurred) {
1452   assert(root != NULL, "just checking");
1453   oop obj = *root;
1454   if (obj == NULL || is_alive->do_object_b(obj)) {
1455       return false;
1456   }
1457   if (obj->is_compiledICHolder()) {
1458     compiledICHolderOop cichk_oop = compiledICHolderOop(obj);
1459     if (is_alive->do_object_b(
1460           cichk_oop->holder_method()->method_holder()) &&
1461         is_alive->do_object_b(cichk_oop->holder_klass())) {
1462       // The oop should be kept alive
1463       keep_alive->do_oop(root);
1464       return false;
1465     }
1466   }
1467   // If ScavengeRootsInCode is true, an nmethod might be unloaded
1468   // simply because one of its constant oops has gone dead.
1469   // No actual classes need to be unloaded in order for this to occur.
1470   assert(unloading_occurred || ScavengeRootsInCode, "Inconsistency in unloading");
1471   make_unloaded(is_alive, obj);
1472   return true;
1473 }
1474 
1475 // ------------------------------------------------------------------
1476 // post_compiled_method_load_event
1477 // new method for install_code() path
1478 // Transfer information from compilation to jvmti
1479 void nmethod::post_compiled_method_load_event() {
1480 
1481   methodOop moop = method();
1482   HS_DTRACE_PROBE8(hotspot, compiled__method__load,
1483       moop->klass_name()->bytes(),
1484       moop->klass_name()->utf8_length(),
1485       moop->name()->bytes(),
1486       moop->name()->utf8_length(),
1487       moop->signature()->bytes(),
1488       moop->signature()->utf8_length(),
1489       code_begin(), code_size());
1490 
1491   if (JvmtiExport::should_post_compiled_method_load()) {
1492     JvmtiExport::post_compiled_method_load(this);
1493   }
1494 }
1495 
1496 void nmethod::post_compiled_method_unload() {
1497   if (unload_reported()) {
1498     // During unloading we transition to unloaded and then to zombie
1499     // and the unloading is reported during the first transition.
1500     return;
1501   }
1502 
1503   assert(_method != NULL && !is_unloaded(), "just checking");
1504   DTRACE_METHOD_UNLOAD_PROBE(method());
1505 
1506   // If a JVMTI agent has enabled the CompiledMethodUnload event then
1507   // post the event. Sometime later this nmethod will be made a zombie by
1508   // the sweeper but the methodOop will not be valid at that point.
1509   if (JvmtiExport::should_post_compiled_method_unload()) {
1510     assert(!unload_reported(), "already unloaded");
1511     HandleMark hm;
1512     JvmtiExport::post_compiled_method_unload(method()->jmethod_id(), code_begin());
1513   }
1514 
1515   // The JVMTI CompiledMethodUnload event can be enabled or disabled at
1516   // any time. As the nmethod is being unloaded now we mark it has
1517   // having the unload event reported - this will ensure that we don't
1518   // attempt to report the event in the unlikely scenario where the
1519   // event is enabled at the time the nmethod is made a zombie.
1520   set_unload_reported();
1521 }
1522 
1523 // This is called at the end of the strong tracing/marking phase of a
1524 // GC to unload an nmethod if it contains otherwise unreachable
1525 // oops.
1526 
1527 void nmethod::do_unloading(BoolObjectClosure* is_alive,
1528                            OopClosure* keep_alive, bool unloading_occurred) {
1529   // Make sure the oop's ready to receive visitors
1530   assert(!is_zombie() && !is_unloaded(),
1531          "should not call follow on zombie or unloaded nmethod");
1532 
1533   // If the method is not entrant then a JMP is plastered over the
1534   // first few bytes.  If an oop in the old code was there, that oop
1535   // should not get GC'd.  Skip the first few bytes of oops on
1536   // not-entrant methods.
1537   address low_boundary = verified_entry_point();
1538   if (is_not_entrant()) {
1539     low_boundary += NativeJump::instruction_size;
1540     // %%% Note:  On SPARC we patch only a 4-byte trap, not a full NativeJump.
1541     // (See comment above.)
1542   }
1543 
1544   // The RedefineClasses() API can cause the class unloading invariant
1545   // to no longer be true. See jvmtiExport.hpp for details.
1546   // Also, leave a debugging breadcrumb in local flag.
1547   bool a_class_was_redefined = JvmtiExport::has_redefined_a_class();
1548   if (a_class_was_redefined) {
1549     // This set of the unloading_occurred flag is done before the
1550     // call to post_compiled_method_unload() so that the unloading
1551     // of this nmethod is reported.
1552     unloading_occurred = true;
1553   }
1554 
1555   // Follow methodOop
1556   if (can_unload(is_alive, keep_alive, (oop*)&_method, unloading_occurred)) {
1557     return;
1558   }
1559 
1560   // Exception cache
1561   ExceptionCache* ec = exception_cache();
1562   while (ec != NULL) {
1563     oop* ex_addr = (oop*)ec->exception_type_addr();
1564     oop ex = *ex_addr;
1565     ExceptionCache* next_ec = ec->next();
1566     if (ex != NULL && !is_alive->do_object_b(ex)) {
1567       assert(!ex->is_compiledICHolder(), "Possible error here");
1568       remove_from_exception_cache(ec);
1569     }
1570     ec = next_ec;
1571   }
1572 
1573   // If class unloading occurred we first iterate over all inline caches and
1574   // clear ICs where the cached oop is referring to an unloaded klass or method.
1575   // The remaining live cached oops will be traversed in the relocInfo::oop_type
1576   // iteration below.
1577   if (unloading_occurred) {
1578     RelocIterator iter(this, low_boundary);
1579     while(iter.next()) {
1580       if (iter.type() == relocInfo::virtual_call_type) {
1581         CompiledIC *ic = CompiledIC_at(iter.reloc());
1582         oop ic_oop = ic->cached_oop();
1583         if (ic_oop != NULL && !is_alive->do_object_b(ic_oop)) {
1584           // The only exception is compiledICHolder oops which may
1585           // yet be marked below. (We check this further below).
1586           if (ic_oop->is_compiledICHolder()) {
1587             compiledICHolderOop cichk_oop = compiledICHolderOop(ic_oop);
1588             if (is_alive->do_object_b(
1589                   cichk_oop->holder_method()->method_holder()) &&
1590                 is_alive->do_object_b(cichk_oop->holder_klass())) {
1591               continue;
1592             }
1593           }
1594           ic->set_to_clean();
1595           assert(ic->cached_oop() == NULL,
1596                  "cached oop in IC should be cleared");
1597         }
1598       }
1599     }
1600   }
1601 
1602   // Compiled code
1603   RelocIterator iter(this, low_boundary);
1604   while (iter.next()) {
1605     if (iter.type() == relocInfo::oop_type) {
1606       oop_Relocation* r = iter.oop_reloc();
1607       // In this loop, we must only traverse those oops directly embedded in
1608       // the code.  Other oops (oop_index>0) are seen as part of scopes_oops.
1609       assert(1 == (r->oop_is_immediate()) +
1610                   (r->oop_addr() >= oops_begin() && r->oop_addr() < oops_end()),
1611              "oop must be found in exactly one place");
1612       if (r->oop_is_immediate() && r->oop_value() != NULL) {
1613         if (can_unload(is_alive, keep_alive, r->oop_addr(), unloading_occurred)) {
1614           return;
1615         }
1616       }
1617     }
1618   }
1619 
1620 
1621   // Scopes
1622   for (oop* p = oops_begin(); p < oops_end(); p++) {
1623     if (*p == Universe::non_oop_word())  continue;  // skip non-oops
1624     if (can_unload(is_alive, keep_alive, p, unloading_occurred)) {
1625       return;
1626     }
1627   }
1628 
1629 #ifndef PRODUCT
1630   // This nmethod was not unloaded; check below that all CompiledICs
1631   // refer to marked oops.
1632   {
1633     RelocIterator iter(this, low_boundary);
1634     while (iter.next()) {
1635       if (iter.type() == relocInfo::virtual_call_type) {
1636          CompiledIC *ic = CompiledIC_at(iter.reloc());
1637          oop ic_oop = ic->cached_oop();
1638          assert(ic_oop == NULL || is_alive->do_object_b(ic_oop),
1639                 "Found unmarked ic_oop in reachable nmethod");
1640        }
1641     }
1642   }
1643 #endif // !PRODUCT
1644 }
1645 
1646 // This method is called twice during GC -- once while
1647 // tracing the "active" nmethods on thread stacks during
1648 // the (strong) marking phase, and then again when walking
1649 // the code cache contents during the weak roots processing
1650 // phase. The two uses are distinguished by means of the
1651 // 'do_strong_roots_only' flag, which is true in the first
1652 // case. We want to walk the weak roots in the nmethod
1653 // only in the second case. The weak roots in the nmethod
1654 // are the oops in the ExceptionCache and the InlineCache
1655 // oops.
1656 void nmethod::oops_do(OopClosure* f, bool do_strong_roots_only) {
1657   // make sure the oops ready to receive visitors
1658   assert(!is_zombie() && !is_unloaded(),
1659          "should not call follow on zombie or unloaded nmethod");
1660 
1661   // If the method is not entrant or zombie then a JMP is plastered over the
1662   // first few bytes.  If an oop in the old code was there, that oop
1663   // should not get GC'd.  Skip the first few bytes of oops on
1664   // not-entrant methods.
1665   address low_boundary = verified_entry_point();
1666   if (is_not_entrant()) {
1667     low_boundary += NativeJump::instruction_size;
1668     // %%% Note:  On SPARC we patch only a 4-byte trap, not a full NativeJump.
1669     // (See comment above.)
1670   }
1671 
1672   // Compiled code
1673   f->do_oop((oop*) &_method);
1674   if (!do_strong_roots_only) {
1675     // weak roots processing phase -- update ExceptionCache oops
1676     ExceptionCache* ec = exception_cache();
1677     while(ec != NULL) {
1678       f->do_oop((oop*)ec->exception_type_addr());
1679       ec = ec->next();
1680     }
1681   } // Else strong roots phase -- skip oops in ExceptionCache
1682 
1683   RelocIterator iter(this, low_boundary);
1684 
1685   while (iter.next()) {
1686     if (iter.type() == relocInfo::oop_type ) {
1687       oop_Relocation* r = iter.oop_reloc();
1688       // In this loop, we must only follow those oops directly embedded in
1689       // the code.  Other oops (oop_index>0) are seen as part of scopes_oops.
1690       assert(1 == (r->oop_is_immediate()) +
1691                    (r->oop_addr() >= oops_begin() && r->oop_addr() < oops_end()),
1692              "oop must be found in exactly one place");
1693       if (r->oop_is_immediate() && r->oop_value() != NULL) {
1694         f->do_oop(r->oop_addr());
1695       }
1696     }
1697   }
1698 
1699   // Scopes
1700   // This includes oop constants not inlined in the code stream.
1701   for (oop* p = oops_begin(); p < oops_end(); p++) {
1702     if (*p == Universe::non_oop_word())  continue;  // skip non-oops
1703     f->do_oop(p);
1704   }
1705 }
1706 
1707 #define NMETHOD_SENTINEL ((nmethod*)badAddress)
1708 
1709 nmethod* volatile nmethod::_oops_do_mark_nmethods;
1710 
1711 // An nmethod is "marked" if its _mark_link is set non-null.
1712 // Even if it is the end of the linked list, it will have a non-null link value,
1713 // as long as it is on the list.
1714 // This code must be MP safe, because it is used from parallel GC passes.
1715 bool nmethod::test_set_oops_do_mark() {
1716   assert(nmethod::oops_do_marking_is_active(), "oops_do_marking_prologue must be called");
1717   nmethod* observed_mark_link = _oops_do_mark_link;
1718   if (observed_mark_link == NULL) {
1719     // Claim this nmethod for this thread to mark.
1720     observed_mark_link = (nmethod*)
1721       Atomic::cmpxchg_ptr(NMETHOD_SENTINEL, &_oops_do_mark_link, NULL);
1722     if (observed_mark_link == NULL) {
1723 
1724       // Atomically append this nmethod (now claimed) to the head of the list:
1725       nmethod* observed_mark_nmethods = _oops_do_mark_nmethods;
1726       for (;;) {
1727         nmethod* required_mark_nmethods = observed_mark_nmethods;
1728         _oops_do_mark_link = required_mark_nmethods;
1729         observed_mark_nmethods = (nmethod*)
1730           Atomic::cmpxchg_ptr(this, &_oops_do_mark_nmethods, required_mark_nmethods);
1731         if (observed_mark_nmethods == required_mark_nmethods)
1732           break;
1733       }
1734       // Mark was clear when we first saw this guy.
1735       NOT_PRODUCT(if (TraceScavenge)  print_on(tty, "oops_do, mark\n"));
1736       return false;
1737     }
1738   }
1739   // On fall through, another racing thread marked this nmethod before we did.
1740   return true;
1741 }
1742 
1743 void nmethod::oops_do_marking_prologue() {
1744   NOT_PRODUCT(if (TraceScavenge)  tty->print_cr("[oops_do_marking_prologue"));
1745   assert(_oops_do_mark_nmethods == NULL, "must not call oops_do_marking_prologue twice in a row");
1746   // We use cmpxchg_ptr instead of regular assignment here because the user
1747   // may fork a bunch of threads, and we need them all to see the same state.
1748   void* observed = Atomic::cmpxchg_ptr(NMETHOD_SENTINEL, &_oops_do_mark_nmethods, NULL);
1749   guarantee(observed == NULL, "no races in this sequential code");
1750 }
1751 
1752 void nmethod::oops_do_marking_epilogue() {
1753   assert(_oops_do_mark_nmethods != NULL, "must not call oops_do_marking_epilogue twice in a row");
1754   nmethod* cur = _oops_do_mark_nmethods;
1755   while (cur != NMETHOD_SENTINEL) {
1756     assert(cur != NULL, "not NULL-terminated");
1757     nmethod* next = cur->_oops_do_mark_link;
1758     cur->_oops_do_mark_link = NULL;
1759     NOT_PRODUCT(if (TraceScavenge)  cur->print_on(tty, "oops_do, unmark\n"));
1760     cur = next;
1761   }
1762   void* required = _oops_do_mark_nmethods;
1763   void* observed = Atomic::cmpxchg_ptr(NULL, &_oops_do_mark_nmethods, required);
1764   guarantee(observed == required, "no races in this sequential code");
1765   NOT_PRODUCT(if (TraceScavenge)  tty->print_cr("oops_do_marking_epilogue]"));
1766 }
1767 
1768 class DetectScavengeRoot: public OopClosure {
1769   bool     _detected_scavenge_root;
1770 public:
1771   DetectScavengeRoot() : _detected_scavenge_root(false)
1772   { NOT_PRODUCT(_print_nm = NULL); }
1773   bool detected_scavenge_root() { return _detected_scavenge_root; }
1774   virtual void do_oop(oop* p) {
1775     if ((*p) != NULL && (*p)->is_scavengable()) {
1776       NOT_PRODUCT(maybe_print(p));
1777       _detected_scavenge_root = true;
1778     }
1779   }
1780   virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
1781 
1782 #ifndef PRODUCT
1783   nmethod* _print_nm;
1784   void maybe_print(oop* p) {
1785     if (_print_nm == NULL)  return;
1786     if (!_detected_scavenge_root)  _print_nm->print_on(tty, "new scavenge root");
1787     tty->print_cr(""PTR_FORMAT"[offset=%d] detected non-perm oop "PTR_FORMAT" (found at "PTR_FORMAT")",
1788                   _print_nm, (int)((intptr_t)p - (intptr_t)_print_nm),
1789                   (intptr_t)(*p), (intptr_t)p);
1790     (*p)->print();
1791   }
1792 #endif //PRODUCT
1793 };
1794 
1795 bool nmethod::detect_scavenge_root_oops() {
1796   DetectScavengeRoot detect_scavenge_root;
1797   NOT_PRODUCT(if (TraceScavenge)  detect_scavenge_root._print_nm = this);
1798   oops_do(&detect_scavenge_root);
1799   return detect_scavenge_root.detected_scavenge_root();
1800 }
1801 
1802 // Method that knows how to preserve outgoing arguments at call. This method must be
1803 // called with a frame corresponding to a Java invoke
1804 void nmethod::preserve_callee_argument_oops(frame fr, const RegisterMap *reg_map, OopClosure* f) {
1805   if (!method()->is_native()) {
1806     SimpleScopeDesc ssd(this, fr.pc());
1807     Bytecode_invoke* call = Bytecode_invoke_at(ssd.method(), ssd.bci());
1808     bool has_receiver = call->has_receiver();
1809     symbolOop signature = call->signature();
1810     fr.oops_compiled_arguments_do(signature, has_receiver, reg_map, f);
1811   }
1812 }
1813 
1814 
1815 oop nmethod::embeddedOop_at(u_char* p) {
1816   RelocIterator iter(this, p, p + oopSize);
1817   while (iter.next())
1818     if (iter.type() == relocInfo::oop_type) {
1819       return iter.oop_reloc()->oop_value();
1820     }
1821   return NULL;
1822 }
1823 
1824 
1825 inline bool includes(void* p, void* from, void* to) {
1826   return from <= p && p < to;
1827 }
1828 
1829 
1830 void nmethod::copy_scopes_pcs(PcDesc* pcs, int count) {
1831   assert(count >= 2, "must be sentinel values, at least");
1832 
1833 #ifdef ASSERT
1834   // must be sorted and unique; we do a binary search in find_pc_desc()
1835   int prev_offset = pcs[0].pc_offset();
1836   assert(prev_offset == PcDesc::lower_offset_limit,
1837          "must start with a sentinel");
1838   for (int i = 1; i < count; i++) {
1839     int this_offset = pcs[i].pc_offset();
1840     assert(this_offset > prev_offset, "offsets must be sorted");
1841     prev_offset = this_offset;
1842   }
1843   assert(prev_offset == PcDesc::upper_offset_limit,
1844          "must end with a sentinel");
1845 #endif //ASSERT
1846 
1847   // Search for MethodHandle invokes and tag the nmethod.
1848   for (int i = 0; i < count; i++) {
1849     if (pcs[i].is_method_handle_invoke()) {
1850       set_has_method_handle_invokes(true);
1851       break;
1852     }
1853   }
1854 
1855   int size = count * sizeof(PcDesc);
1856   assert(scopes_pcs_size() >= size, "oob");
1857   memcpy(scopes_pcs_begin(), pcs, size);
1858 
1859   // Adjust the final sentinel downward.
1860   PcDesc* last_pc = &scopes_pcs_begin()[count-1];
1861   assert(last_pc->pc_offset() == PcDesc::upper_offset_limit, "sanity");
1862   last_pc->set_pc_offset(instructions_size() + 1);
1863   for (; last_pc + 1 < scopes_pcs_end(); last_pc += 1) {
1864     // Fill any rounding gaps with copies of the last record.
1865     last_pc[1] = last_pc[0];
1866   }
1867   // The following assert could fail if sizeof(PcDesc) is not
1868   // an integral multiple of oopSize (the rounding term).
1869   // If it fails, change the logic to always allocate a multiple
1870   // of sizeof(PcDesc), and fill unused words with copies of *last_pc.
1871   assert(last_pc + 1 == scopes_pcs_end(), "must match exactly");
1872 }
1873 
1874 void nmethod::copy_scopes_data(u_char* buffer, int size) {
1875   assert(scopes_data_size() >= size, "oob");
1876   memcpy(scopes_data_begin(), buffer, size);
1877 }
1878 
1879 
1880 #ifdef ASSERT
1881 static PcDesc* linear_search(nmethod* nm, int pc_offset, bool approximate) {
1882   PcDesc* lower = nm->scopes_pcs_begin();
1883   PcDesc* upper = nm->scopes_pcs_end();
1884   lower += 1; // exclude initial sentinel
1885   PcDesc* res = NULL;
1886   for (PcDesc* p = lower; p < upper; p++) {
1887     NOT_PRODUCT(--nmethod_stats.pc_desc_tests);  // don't count this call to match_desc
1888     if (match_desc(p, pc_offset, approximate)) {
1889       if (res == NULL)
1890         res = p;
1891       else
1892         res = (PcDesc*) badAddress;
1893     }
1894   }
1895   return res;
1896 }
1897 #endif
1898 
1899 
1900 // Finds a PcDesc with real-pc equal to "pc"
1901 PcDesc* nmethod::find_pc_desc_internal(address pc, bool approximate) {
1902   address base_address = instructions_begin();
1903   if ((pc < base_address) ||
1904       (pc - base_address) >= (ptrdiff_t) PcDesc::upper_offset_limit) {
1905     return NULL;  // PC is wildly out of range
1906   }
1907   int pc_offset = (int) (pc - base_address);
1908 
1909   // Check the PcDesc cache if it contains the desired PcDesc
1910   // (This as an almost 100% hit rate.)
1911   PcDesc* res = _pc_desc_cache.find_pc_desc(pc_offset, approximate);
1912   if (res != NULL) {
1913     assert(res == linear_search(this, pc_offset, approximate), "cache ok");
1914     return res;
1915   }
1916 
1917   // Fallback algorithm: quasi-linear search for the PcDesc
1918   // Find the last pc_offset less than the given offset.
1919   // The successor must be the required match, if there is a match at all.
1920   // (Use a fixed radix to avoid expensive affine pointer arithmetic.)
1921   PcDesc* lower = scopes_pcs_begin();
1922   PcDesc* upper = scopes_pcs_end();
1923   upper -= 1; // exclude final sentinel
1924   if (lower >= upper)  return NULL;  // native method; no PcDescs at all
1925 
1926 #define assert_LU_OK \
1927   /* invariant on lower..upper during the following search: */ \
1928   assert(lower->pc_offset() <  pc_offset, "sanity"); \
1929   assert(upper->pc_offset() >= pc_offset, "sanity")
1930   assert_LU_OK;
1931 
1932   // Use the last successful return as a split point.
1933   PcDesc* mid = _pc_desc_cache.last_pc_desc();
1934   NOT_PRODUCT(++nmethod_stats.pc_desc_searches);
1935   if (mid->pc_offset() < pc_offset) {
1936     lower = mid;
1937   } else {
1938     upper = mid;
1939   }
1940 
1941   // Take giant steps at first (4096, then 256, then 16, then 1)
1942   const int LOG2_RADIX = 4 /*smaller steps in debug mode:*/ debug_only(-1);
1943   const int RADIX = (1 << LOG2_RADIX);
1944   for (int step = (1 << (LOG2_RADIX*3)); step > 1; step >>= LOG2_RADIX) {
1945     while ((mid = lower + step) < upper) {
1946       assert_LU_OK;
1947       NOT_PRODUCT(++nmethod_stats.pc_desc_searches);
1948       if (mid->pc_offset() < pc_offset) {
1949         lower = mid;
1950       } else {
1951         upper = mid;
1952         break;
1953       }
1954     }
1955     assert_LU_OK;
1956   }
1957 
1958   // Sneak up on the value with a linear search of length ~16.
1959   while (true) {
1960     assert_LU_OK;
1961     mid = lower + 1;
1962     NOT_PRODUCT(++nmethod_stats.pc_desc_searches);
1963     if (mid->pc_offset() < pc_offset) {
1964       lower = mid;
1965     } else {
1966       upper = mid;
1967       break;
1968     }
1969   }
1970 #undef assert_LU_OK
1971 
1972   if (match_desc(upper, pc_offset, approximate)) {
1973     assert(upper == linear_search(this, pc_offset, approximate), "search ok");
1974     _pc_desc_cache.add_pc_desc(upper);
1975     return upper;
1976   } else {
1977     assert(NULL == linear_search(this, pc_offset, approximate), "search ok");
1978     return NULL;
1979   }
1980 }
1981 
1982 
1983 bool nmethod::check_all_dependencies() {
1984   bool found_check = false;
1985   // wholesale check of all dependencies
1986   for (Dependencies::DepStream deps(this); deps.next(); ) {
1987     if (deps.check_dependency() != NULL) {
1988       found_check = true;
1989       NOT_DEBUG(break);
1990     }
1991   }
1992   return found_check;  // tell caller if we found anything
1993 }
1994 
1995 bool nmethod::check_dependency_on(DepChange& changes) {
1996   // What has happened:
1997   // 1) a new class dependee has been added
1998   // 2) dependee and all its super classes have been marked
1999   bool found_check = false;  // set true if we are upset
2000   for (Dependencies::DepStream deps(this); deps.next(); ) {
2001     // Evaluate only relevant dependencies.
2002     if (deps.spot_check_dependency_at(changes) != NULL) {
2003       found_check = true;
2004       NOT_DEBUG(break);
2005     }
2006   }
2007   return found_check;
2008 }
2009 
2010 bool nmethod::is_evol_dependent_on(klassOop dependee) {
2011   instanceKlass *dependee_ik = instanceKlass::cast(dependee);
2012   objArrayOop dependee_methods = dependee_ik->methods();
2013   for (Dependencies::DepStream deps(this); deps.next(); ) {
2014     if (deps.type() == Dependencies::evol_method) {
2015       methodOop method = deps.method_argument(0);
2016       for (int j = 0; j < dependee_methods->length(); j++) {
2017         if ((methodOop) dependee_methods->obj_at(j) == method) {
2018           // RC_TRACE macro has an embedded ResourceMark
2019           RC_TRACE(0x01000000,
2020             ("Found evol dependency of nmethod %s.%s(%s) compile_id=%d on method %s.%s(%s)",
2021             _method->method_holder()->klass_part()->external_name(),
2022             _method->name()->as_C_string(),
2023             _method->signature()->as_C_string(), compile_id(),
2024             method->method_holder()->klass_part()->external_name(),
2025             method->name()->as_C_string(),
2026             method->signature()->as_C_string()));
2027           if (TraceDependencies || LogCompilation)
2028             deps.log_dependency(dependee);
2029           return true;
2030         }
2031       }
2032     }
2033   }
2034   return false;
2035 }
2036 
2037 // Called from mark_for_deoptimization, when dependee is invalidated.
2038 bool nmethod::is_dependent_on_method(methodOop dependee) {
2039   for (Dependencies::DepStream deps(this); deps.next(); ) {
2040     if (deps.type() != Dependencies::evol_method)
2041       continue;
2042     methodOop method = deps.method_argument(0);
2043     if (method == dependee) return true;
2044   }
2045   return false;
2046 }
2047 
2048 
2049 bool nmethod::is_patchable_at(address instr_addr) {
2050   assert (code_contains(instr_addr), "wrong nmethod used");
2051   if (is_zombie()) {
2052     // a zombie may never be patched
2053     return false;
2054   }
2055   return true;
2056 }
2057 
2058 
2059 address nmethod::continuation_for_implicit_exception(address pc) {
2060   // Exception happened outside inline-cache check code => we are inside
2061   // an active nmethod => use cpc to determine a return address
2062   int exception_offset = pc - instructions_begin();
2063   int cont_offset = ImplicitExceptionTable(this).at( exception_offset );
2064 #ifdef ASSERT
2065   if (cont_offset == 0) {
2066     Thread* thread = ThreadLocalStorage::get_thread_slow();
2067     ResetNoHandleMark rnm; // Might be called from LEAF/QUICK ENTRY
2068     HandleMark hm(thread);
2069     ResourceMark rm(thread);
2070     CodeBlob* cb = CodeCache::find_blob(pc);
2071     assert(cb != NULL && cb == this, "");
2072     tty->print_cr("implicit exception happened at " INTPTR_FORMAT, pc);
2073     print();
2074     method()->print_codes();
2075     print_code();
2076     print_pcs();
2077   }
2078 #endif
2079   if (cont_offset == 0) {
2080     // Let the normal error handling report the exception
2081     return NULL;
2082   }
2083   return instructions_begin() + cont_offset;
2084 }
2085 
2086 
2087 
2088 void nmethod_init() {
2089   // make sure you didn't forget to adjust the filler fields
2090   assert(sizeof(nmFlags) <= 4,           "nmFlags occupies more than a word");
2091   assert(sizeof(nmethod) % oopSize == 0, "nmethod size must be multiple of a word");
2092 }
2093 
2094 
2095 //-------------------------------------------------------------------------------------------
2096 
2097 
2098 // QQQ might we make this work from a frame??
2099 nmethodLocker::nmethodLocker(address pc) {
2100   CodeBlob* cb = CodeCache::find_blob(pc);
2101   guarantee(cb != NULL && cb->is_nmethod(), "bad pc for a nmethod found");
2102   _nm = (nmethod*)cb;
2103   lock_nmethod(_nm);
2104 }
2105 
2106 void nmethodLocker::lock_nmethod(nmethod* nm) {
2107   if (nm == NULL)  return;
2108   Atomic::inc(&nm->_lock_count);
2109   guarantee(!nm->is_zombie(), "cannot lock a zombie method");
2110 }
2111 
2112 void nmethodLocker::unlock_nmethod(nmethod* nm) {
2113   if (nm == NULL)  return;
2114   Atomic::dec(&nm->_lock_count);
2115   guarantee(nm->_lock_count >= 0, "unmatched nmethod lock/unlock");
2116 }
2117 
2118 
2119 // -----------------------------------------------------------------------------
2120 // nmethod::get_deopt_original_pc
2121 //
2122 // Return the original PC for the given PC if:
2123 // (a) the given PC belongs to a nmethod and
2124 // (b) it is a deopt PC
2125 address nmethod::get_deopt_original_pc(const frame* fr) {
2126   if (fr->cb() == NULL)  return NULL;
2127 
2128   nmethod* nm = fr->cb()->as_nmethod_or_null();
2129   if (nm != NULL && nm->is_deopt_pc(fr->pc()))
2130     return nm->get_original_pc(fr);
2131 
2132   return NULL;
2133 }
2134 
2135 
2136 // -----------------------------------------------------------------------------
2137 // MethodHandle
2138 
2139 bool nmethod::is_method_handle_return(address return_pc) {
2140   if (!has_method_handle_invokes())  return false;
2141   PcDesc* pd = pc_desc_at(return_pc);
2142   if (pd == NULL)
2143     return false;
2144   return pd->is_method_handle_invoke();
2145 }
2146 
2147 
2148 // -----------------------------------------------------------------------------
2149 // Verification
2150 
2151 class VerifyOopsClosure: public OopClosure {
2152   nmethod* _nm;
2153   bool     _ok;
2154 public:
2155   VerifyOopsClosure(nmethod* nm) : _nm(nm), _ok(true) { }
2156   bool ok() { return _ok; }
2157   virtual void do_oop(oop* p) {
2158     if ((*p) == NULL || (*p)->is_oop())  return;
2159     if (_ok) {
2160       _nm->print_nmethod(true);
2161       _ok = false;
2162     }
2163     tty->print_cr("*** non-oop "PTR_FORMAT" found at "PTR_FORMAT" (offset %d)",
2164                   (intptr_t)(*p), (intptr_t)p, (int)((intptr_t)p - (intptr_t)_nm));
2165   }
2166   virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
2167 };
2168 
2169 void nmethod::verify() {
2170 
2171   // Hmm. OSR methods can be deopted but not marked as zombie or not_entrant
2172   // seems odd.
2173 
2174   if( is_zombie() || is_not_entrant() )
2175     return;
2176 
2177   // Make sure all the entry points are correctly aligned for patching.
2178   NativeJump::check_verified_entry_alignment(entry_point(), verified_entry_point());
2179 
2180   assert(method()->is_oop(), "must be valid");
2181 
2182   ResourceMark rm;
2183 
2184   if (!CodeCache::contains(this)) {
2185     fatal(err_msg("nmethod at " INTPTR_FORMAT " not in zone", this));
2186   }
2187 
2188   if(is_native_method() )
2189     return;
2190 
2191   nmethod* nm = CodeCache::find_nmethod(verified_entry_point());
2192   if (nm != this) {
2193     fatal(err_msg("findNMethod did not find this nmethod (" INTPTR_FORMAT ")",
2194                   this));
2195   }
2196 
2197   for (PcDesc* p = scopes_pcs_begin(); p < scopes_pcs_end(); p++) {
2198     if (! p->verify(this)) {
2199       tty->print_cr("\t\tin nmethod at " INTPTR_FORMAT " (pcs)", this);
2200     }
2201   }
2202 
2203   VerifyOopsClosure voc(this);
2204   oops_do(&voc);
2205   assert(voc.ok(), "embedded oops must be OK");
2206   verify_scavenge_root_oops();
2207 
2208   verify_scopes();
2209 }
2210 
2211 
2212 void nmethod::verify_interrupt_point(address call_site) {
2213   // This code does not work in release mode since
2214   // owns_lock only is available in debug mode.
2215   CompiledIC* ic = NULL;
2216   Thread *cur = Thread::current();
2217   if (CompiledIC_lock->owner() == cur ||
2218       ((cur->is_VM_thread() || cur->is_ConcurrentGC_thread()) &&
2219        SafepointSynchronize::is_at_safepoint())) {
2220     ic = CompiledIC_at(call_site);
2221     CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops());
2222   } else {
2223     MutexLocker ml_verify (CompiledIC_lock);
2224     ic = CompiledIC_at(call_site);
2225   }
2226   PcDesc* pd = pc_desc_at(ic->end_of_call());
2227   assert(pd != NULL, "PcDesc must exist");
2228   for (ScopeDesc* sd = new ScopeDesc(this, pd->scope_decode_offset(),
2229                                      pd->obj_decode_offset(), pd->should_reexecute(),
2230                                      pd->return_oop());
2231        !sd->is_top(); sd = sd->sender()) {
2232     sd->verify();
2233   }
2234 }
2235 
2236 void nmethod::verify_scopes() {
2237   if( !method() ) return;       // Runtime stubs have no scope
2238   if (method()->is_native()) return; // Ignore stub methods.
2239   // iterate through all interrupt point
2240   // and verify the debug information is valid.
2241   RelocIterator iter((nmethod*)this);
2242   while (iter.next()) {
2243     address stub = NULL;
2244     switch (iter.type()) {
2245       case relocInfo::virtual_call_type:
2246         verify_interrupt_point(iter.addr());
2247         break;
2248       case relocInfo::opt_virtual_call_type:
2249         stub = iter.opt_virtual_call_reloc()->static_stub();
2250         verify_interrupt_point(iter.addr());
2251         break;
2252       case relocInfo::static_call_type:
2253         stub = iter.static_call_reloc()->static_stub();
2254         //verify_interrupt_point(iter.addr());
2255         break;
2256       case relocInfo::runtime_call_type:
2257         address destination = iter.reloc()->value();
2258         // Right now there is no way to find out which entries support
2259         // an interrupt point.  It would be nice if we had this
2260         // information in a table.
2261         break;
2262     }
2263     assert(stub == NULL || stub_contains(stub), "static call stub outside stub section");
2264   }
2265 }
2266 
2267 
2268 // -----------------------------------------------------------------------------
2269 // Non-product code
2270 #ifndef PRODUCT
2271 
2272 class DebugScavengeRoot: public OopClosure {
2273   nmethod* _nm;
2274   bool     _ok;
2275 public:
2276   DebugScavengeRoot(nmethod* nm) : _nm(nm), _ok(true) { }
2277   bool ok() { return _ok; }
2278   virtual void do_oop(oop* p) {
2279     if ((*p) == NULL || !(*p)->is_scavengable())  return;
2280     if (_ok) {
2281       _nm->print_nmethod(true);
2282       _ok = false;
2283     }
2284     tty->print_cr("*** non-perm oop "PTR_FORMAT" found at "PTR_FORMAT" (offset %d)",
2285                   (intptr_t)(*p), (intptr_t)p, (int)((intptr_t)p - (intptr_t)_nm));
2286     (*p)->print();
2287   }
2288   virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
2289 };
2290 
2291 void nmethod::verify_scavenge_root_oops() {
2292   if (!on_scavenge_root_list()) {
2293     // Actually look inside, to verify the claim that it's clean.
2294     DebugScavengeRoot debug_scavenge_root(this);
2295     oops_do(&debug_scavenge_root);
2296     if (!debug_scavenge_root.ok())
2297       fatal("found an unadvertised bad non-perm oop in the code cache");
2298   }
2299   assert(scavenge_root_not_marked(), "");
2300 }
2301 
2302 #endif // PRODUCT
2303 
2304 // Printing operations
2305 
2306 void nmethod::print() const {
2307   ResourceMark rm;
2308   ttyLocker ttyl;   // keep the following output all in one block
2309 
2310   tty->print("Compiled ");
2311 
2312   if (is_compiled_by_c1()) {
2313     tty->print("(c1) ");
2314   } else if (is_compiled_by_c2()) {
2315     tty->print("(c2) ");
2316   } else {
2317     tty->print("(nm) ");
2318   }
2319 
2320   print_on(tty, "nmethod");
2321   tty->cr();
2322   if (WizardMode) {
2323     tty->print("((nmethod*) "INTPTR_FORMAT ") ", this);
2324     tty->print(" for method " INTPTR_FORMAT , (address)method());
2325     tty->print(" { ");
2326     if (version())        tty->print("v%d ", version());
2327     if (is_in_use())      tty->print("in_use ");
2328     if (is_not_entrant()) tty->print("not_entrant ");
2329     if (is_zombie())      tty->print("zombie ");
2330     if (is_unloaded())    tty->print("unloaded ");
2331     if (on_scavenge_root_list())  tty->print("scavenge_root ");
2332     tty->print_cr("}:");
2333   }
2334   if (size              () > 0) tty->print_cr(" total in heap  [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2335                                               (address)this,
2336                                               (address)this + size(),
2337                                               size());
2338   if (relocation_size   () > 0) tty->print_cr(" relocation     [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2339                                               relocation_begin(),
2340                                               relocation_end(),
2341                                               relocation_size());
2342   if (code_size         () > 0) tty->print_cr(" main code      [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2343                                               code_begin(),
2344                                               code_end(),
2345                                               code_size());
2346   if (stub_size         () > 0) tty->print_cr(" stub code      [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2347                                               stub_begin(),
2348                                               stub_end(),
2349                                               stub_size());
2350   if (consts_size       () > 0) tty->print_cr(" constants      [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2351                                               consts_begin(),
2352                                               consts_end(),
2353                                               consts_size());
2354   if (oops_size         () > 0) tty->print_cr(" oops           [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2355                                               oops_begin(),
2356                                               oops_end(),
2357                                               oops_size());
2358   if (scopes_data_size  () > 0) tty->print_cr(" scopes data    [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2359                                               scopes_data_begin(),
2360                                               scopes_data_end(),
2361                                               scopes_data_size());
2362   if (scopes_pcs_size   () > 0) tty->print_cr(" scopes pcs     [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2363                                               scopes_pcs_begin(),
2364                                               scopes_pcs_end(),
2365                                               scopes_pcs_size());
2366   if (dependencies_size () > 0) tty->print_cr(" dependencies   [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2367                                               dependencies_begin(),
2368                                               dependencies_end(),
2369                                               dependencies_size());
2370   if (handler_table_size() > 0) tty->print_cr(" handler table  [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2371                                               handler_table_begin(),
2372                                               handler_table_end(),
2373                                               handler_table_size());
2374   if (nul_chk_table_size() > 0) tty->print_cr(" nul chk table  [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2375                                               nul_chk_table_begin(),
2376                                               nul_chk_table_end(),
2377                                               nul_chk_table_size());
2378   if (oops_size         () > 0) tty->print_cr(" oops           [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",
2379                                               oops_begin(),
2380                                               oops_end(),
2381                                               oops_size());
2382 }
2383 
2384 void nmethod::print_code() {
2385   HandleMark hm;
2386   ResourceMark m;
2387   Disassembler::decode(this);
2388 }
2389 
2390 
2391 #ifndef PRODUCT
2392 
2393 void nmethod::print_scopes() {
2394   // Find the first pc desc for all scopes in the code and print it.
2395   ResourceMark rm;
2396   for (PcDesc* p = scopes_pcs_begin(); p < scopes_pcs_end(); p++) {
2397     if (p->scope_decode_offset() == DebugInformationRecorder::serialized_null)
2398       continue;
2399 
2400     ScopeDesc* sd = scope_desc_at(p->real_pc(this));
2401     sd->print_on(tty, p);
2402   }
2403 }
2404 
2405 void nmethod::print_dependencies() {
2406   ResourceMark rm;
2407   ttyLocker ttyl;   // keep the following output all in one block
2408   tty->print_cr("Dependencies:");
2409   for (Dependencies::DepStream deps(this); deps.next(); ) {
2410     deps.print_dependency();
2411     klassOop ctxk = deps.context_type();
2412     if (ctxk != NULL) {
2413       Klass* k = Klass::cast(ctxk);
2414       if (k->oop_is_instance() && ((instanceKlass*)k)->is_dependent_nmethod(this)) {
2415         tty->print_cr("   [nmethod<=klass]%s", k->external_name());
2416       }
2417     }
2418     deps.log_dependency();  // put it into the xml log also
2419   }
2420 }
2421 
2422 
2423 void nmethod::print_relocations() {
2424   ResourceMark m;       // in case methods get printed via the debugger
2425   tty->print_cr("relocations:");
2426   RelocIterator iter(this);
2427   iter.print();
2428   if (UseRelocIndex) {
2429     jint* index_end   = (jint*)relocation_end() - 1;
2430     jint  index_size  = *index_end;
2431     jint* index_start = (jint*)( (address)index_end - index_size );
2432     tty->print_cr("    index @" INTPTR_FORMAT ": index_size=%d", index_start, index_size);
2433     if (index_size > 0) {
2434       jint* ip;
2435       for (ip = index_start; ip+2 <= index_end; ip += 2)
2436         tty->print_cr("  (%d %d) addr=" INTPTR_FORMAT " @" INTPTR_FORMAT,
2437                       ip[0],
2438                       ip[1],
2439                       header_end()+ip[0],
2440                       relocation_begin()-1+ip[1]);
2441       for (; ip < index_end; ip++)
2442         tty->print_cr("  (%d ?)", ip[0]);
2443       tty->print_cr("          @" INTPTR_FORMAT ": index_size=%d", ip, *ip++);
2444       tty->print_cr("reloc_end @" INTPTR_FORMAT ":", ip);
2445     }
2446   }
2447 }
2448 
2449 
2450 void nmethod::print_pcs() {
2451   ResourceMark m;       // in case methods get printed via debugger
2452   tty->print_cr("pc-bytecode offsets:");
2453   for (PcDesc* p = scopes_pcs_begin(); p < scopes_pcs_end(); p++) {
2454     p->print(this);
2455   }
2456 }
2457 
2458 #endif // PRODUCT
2459 
2460 const char* nmethod::reloc_string_for(u_char* begin, u_char* end) {
2461   RelocIterator iter(this, begin, end);
2462   bool have_one = false;
2463   while (iter.next()) {
2464     have_one = true;
2465     switch (iter.type()) {
2466         case relocInfo::none:                  return "no_reloc";
2467         case relocInfo::oop_type: {
2468           stringStream st;
2469           oop_Relocation* r = iter.oop_reloc();
2470           oop obj = r->oop_value();
2471           st.print("oop(");
2472           if (obj == NULL) st.print("NULL");
2473           else obj->print_value_on(&st);
2474           st.print(")");
2475           return st.as_string();
2476         }
2477         case relocInfo::virtual_call_type:     return "virtual_call";
2478         case relocInfo::opt_virtual_call_type: return "optimized virtual_call";
2479         case relocInfo::static_call_type:      return "static_call";
2480         case relocInfo::static_stub_type:      return "static_stub";
2481         case relocInfo::runtime_call_type:     return "runtime_call";
2482         case relocInfo::external_word_type:    return "external_word";
2483         case relocInfo::internal_word_type:    return "internal_word";
2484         case relocInfo::section_word_type:     return "section_word";
2485         case relocInfo::poll_type:             return "poll";
2486         case relocInfo::poll_return_type:      return "poll_return";
2487         case relocInfo::type_mask:             return "type_bit_mask";
2488     }
2489   }
2490   return have_one ? "other" : NULL;
2491 }
2492 
2493 // Return a the last scope in (begin..end]
2494 ScopeDesc* nmethod::scope_desc_in(address begin, address end) {
2495   PcDesc* p = pc_desc_near(begin+1);
2496   if (p != NULL && p->real_pc(this) <= end) {
2497     return new ScopeDesc(this, p->scope_decode_offset(),
2498                          p->obj_decode_offset(), p->should_reexecute(),
2499                          p->return_oop());
2500   }
2501   return NULL;
2502 }
2503 
2504 void nmethod::print_nmethod_labels(outputStream* stream, address block_begin) {
2505   if (block_begin == entry_point())             stream->print_cr("[Entry Point]");
2506   if (block_begin == verified_entry_point())    stream->print_cr("[Verified Entry Point]");
2507   if (block_begin == exception_begin())         stream->print_cr("[Exception Handler]");
2508   if (block_begin == stub_begin())              stream->print_cr("[Stub Code]");
2509   if (block_begin == deopt_handler_begin())     stream->print_cr("[Deopt Handler Code]");
2510   if (block_begin == deopt_mh_handler_begin())  stream->print_cr("[Deopt MH Handler Code]");
2511   if (block_begin == consts_begin())            stream->print_cr("[Constants]");
2512   if (block_begin == entry_point()) {
2513     methodHandle m = method();
2514     if (m.not_null()) {
2515       stream->print("  # ");
2516       m->print_value_on(stream);
2517       stream->cr();
2518     }
2519     if (m.not_null() && !is_osr_method()) {
2520       ResourceMark rm;
2521       int sizeargs = m->size_of_parameters();
2522       BasicType* sig_bt = NEW_RESOURCE_ARRAY(BasicType, sizeargs);
2523       VMRegPair* regs   = NEW_RESOURCE_ARRAY(VMRegPair, sizeargs);
2524       {
2525         int sig_index = 0;
2526         if (!m->is_static())
2527           sig_bt[sig_index++] = T_OBJECT; // 'this'
2528         for (SignatureStream ss(m->signature()); !ss.at_return_type(); ss.next()) {
2529           BasicType t = ss.type();
2530           sig_bt[sig_index++] = t;
2531           if (type2size[t] == 2) {
2532             sig_bt[sig_index++] = T_VOID;
2533           } else {
2534             assert(type2size[t] == 1, "size is 1 or 2");
2535           }
2536         }
2537         assert(sig_index == sizeargs, "");
2538       }
2539       const char* spname = "sp"; // make arch-specific?
2540       intptr_t out_preserve = SharedRuntime::java_calling_convention(sig_bt, regs, sizeargs, false);
2541       int stack_slot_offset = this->frame_size() * wordSize;
2542       int tab1 = 14, tab2 = 24;
2543       int sig_index = 0;
2544       int arg_index = (m->is_static() ? 0 : -1);
2545       bool did_old_sp = false;
2546       for (SignatureStream ss(m->signature()); !ss.at_return_type(); ) {
2547         bool at_this = (arg_index == -1);
2548         bool at_old_sp = false;
2549         BasicType t = (at_this ? T_OBJECT : ss.type());
2550         assert(t == sig_bt[sig_index], "sigs in sync");
2551         if (at_this)
2552           stream->print("  # this: ");
2553         else
2554           stream->print("  # parm%d: ", arg_index);
2555         stream->move_to(tab1);
2556         VMReg fst = regs[sig_index].first();
2557         VMReg snd = regs[sig_index].second();
2558         if (fst->is_reg()) {
2559           stream->print("%s", fst->name());
2560           if (snd->is_valid())  {
2561             stream->print(":%s", snd->name());
2562           }
2563         } else if (fst->is_stack()) {
2564           int offset = fst->reg2stack() * VMRegImpl::stack_slot_size + stack_slot_offset;
2565           if (offset == stack_slot_offset)  at_old_sp = true;
2566           stream->print("[%s+0x%x]", spname, offset);
2567         } else {
2568           stream->print("reg%d:%d??", (int)(intptr_t)fst, (int)(intptr_t)snd);
2569         }
2570         stream->print(" ");
2571         stream->move_to(tab2);
2572         stream->print("= ");
2573         if (at_this) {
2574           m->method_holder()->print_value_on(stream);
2575         } else {
2576           bool did_name = false;
2577           if (!at_this && ss.is_object()) {
2578             symbolOop name = ss.as_symbol_or_null();
2579             if (name != NULL) {
2580               name->print_value_on(stream);
2581               did_name = true;
2582             }
2583           }
2584           if (!did_name)
2585             stream->print("%s", type2name(t));
2586         }
2587         if (at_old_sp) {
2588           stream->print("  (%s of caller)", spname);
2589           did_old_sp = true;
2590         }
2591         stream->cr();
2592         sig_index += type2size[t];
2593         arg_index += 1;
2594         if (!at_this)  ss.next();
2595       }
2596       if (!did_old_sp) {
2597         stream->print("  # ");
2598         stream->move_to(tab1);
2599         stream->print("[%s+0x%x]", spname, stack_slot_offset);
2600         stream->print("  (%s of caller)", spname);
2601         stream->cr();
2602       }
2603     }
2604   }
2605 }
2606 
2607 void nmethod::print_code_comment_on(outputStream* st, int column, u_char* begin, u_char* end) {
2608   // First, find an oopmap in (begin, end].
2609   // We use the odd half-closed interval so that oop maps and scope descs
2610   // which are tied to the byte after a call are printed with the call itself.
2611   address base = instructions_begin();
2612   OopMapSet* oms = oop_maps();
2613   if (oms != NULL) {
2614     for (int i = 0, imax = oms->size(); i < imax; i++) {
2615       OopMap* om = oms->at(i);
2616       address pc = base + om->offset();
2617       if (pc > begin) {
2618         if (pc <= end) {
2619           st->move_to(column);
2620           st->print("; ");
2621           om->print_on(st);
2622         }
2623         break;
2624       }
2625     }
2626   }
2627 
2628   // Print any debug info present at this pc.
2629   ScopeDesc* sd  = scope_desc_in(begin, end);
2630   if (sd != NULL) {
2631     st->move_to(column);
2632     if (sd->bci() == SynchronizationEntryBCI) {
2633       st->print(";*synchronization entry");
2634     } else {
2635       if (sd->method().is_null()) {
2636         st->print("method is NULL");
2637       } else if (sd->method()->is_native()) {
2638         st->print("method is native");
2639       } else {
2640         address bcp  = sd->method()->bcp_from(sd->bci());
2641         Bytecodes::Code bc = Bytecodes::java_code_at(bcp);
2642         st->print(";*%s", Bytecodes::name(bc));
2643         switch (bc) {
2644         case Bytecodes::_invokevirtual:
2645         case Bytecodes::_invokespecial:
2646         case Bytecodes::_invokestatic:
2647         case Bytecodes::_invokeinterface:
2648           {
2649             Bytecode_invoke* invoke = Bytecode_invoke_at(sd->method(), sd->bci());
2650             st->print(" ");
2651             if (invoke->name() != NULL)
2652               invoke->name()->print_symbol_on(st);
2653             else
2654               st->print("<UNKNOWN>");
2655             break;
2656           }
2657         case Bytecodes::_getfield:
2658         case Bytecodes::_putfield:
2659         case Bytecodes::_getstatic:
2660         case Bytecodes::_putstatic:
2661           {
2662             Bytecode_field* field = Bytecode_field_at(sd->method(), sd->bci());
2663             st->print(" ");
2664             if (field->name() != NULL)
2665               field->name()->print_symbol_on(st);
2666             else
2667               st->print("<UNKNOWN>");
2668           }
2669         }
2670       }
2671     }
2672 
2673     // Print all scopes
2674     for (;sd != NULL; sd = sd->sender()) {
2675       st->move_to(column);
2676       st->print("; -");
2677       if (sd->method().is_null()) {
2678         st->print("method is NULL");
2679       } else {
2680         sd->method()->print_short_name(st);
2681       }
2682       int lineno = sd->method()->line_number_from_bci(sd->bci());
2683       if (lineno != -1) {
2684         st->print("@%d (line %d)", sd->bci(), lineno);
2685       } else {
2686         st->print("@%d", sd->bci());
2687       }
2688       st->cr();
2689     }
2690   }
2691 
2692   // Print relocation information
2693   const char* str = reloc_string_for(begin, end);
2694   if (str != NULL) {
2695     if (sd != NULL) st->cr();
2696     st->move_to(column);
2697     st->print(";   {%s}", str);
2698   }
2699   int cont_offset = ImplicitExceptionTable(this).at(begin - instructions_begin());
2700   if (cont_offset != 0) {
2701     st->move_to(column);
2702     st->print("; implicit exception: dispatches to " INTPTR_FORMAT, instructions_begin() + cont_offset);
2703   }
2704 
2705 }
2706 
2707 #ifndef PRODUCT
2708 
2709 void nmethod::print_value_on(outputStream* st) const {
2710   print_on(st, "nmethod");
2711 }
2712 
2713 void nmethod::print_calls(outputStream* st) {
2714   RelocIterator iter(this);
2715   while (iter.next()) {
2716     switch (iter.type()) {
2717     case relocInfo::virtual_call_type:
2718     case relocInfo::opt_virtual_call_type: {
2719       VerifyMutexLocker mc(CompiledIC_lock);
2720       CompiledIC_at(iter.reloc())->print();
2721       break;
2722     }
2723     case relocInfo::static_call_type:
2724       st->print_cr("Static call at " INTPTR_FORMAT, iter.reloc()->addr());
2725       compiledStaticCall_at(iter.reloc())->print();
2726       break;
2727     }
2728   }
2729 }
2730 
2731 void nmethod::print_handler_table() {
2732   ExceptionHandlerTable(this).print();
2733 }
2734 
2735 void nmethod::print_nul_chk_table() {
2736   ImplicitExceptionTable(this).print(instructions_begin());
2737 }
2738 
2739 void nmethod::print_statistics() {
2740   ttyLocker ttyl;
2741   if (xtty != NULL)  xtty->head("statistics type='nmethod'");
2742   nmethod_stats.print_native_nmethod_stats();
2743   nmethod_stats.print_nmethod_stats();
2744   DebugInformationRecorder::print_statistics();
2745   nmethod_stats.print_pc_stats();
2746   Dependencies::print_statistics();
2747   if (xtty != NULL)  xtty->tail("statistics");
2748 }
2749 
2750 #endif // PRODUCT