1 /*
   2  * Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "classfile/systemDictionary.hpp"
  27 #include "interpreter/bytecode.hpp"
  28 #include "interpreter/bytecodeStream.hpp"
  29 #include "interpreter/linkResolver.hpp"
  30 #include "memory/heapInspection.hpp"
  31 #include "oops/methodData.hpp"
  32 #include "prims/jvmtiRedefineClasses.hpp"
  33 #include "runtime/compilationPolicy.hpp"
  34 #include "runtime/deoptimization.hpp"
  35 #include "runtime/handles.inline.hpp"
  36 
  37 // ==================================================================
  38 // DataLayout
  39 //
  40 // Overlay for generic profiling data.
  41 
  42 // Some types of data layouts need a length field.
  43 bool DataLayout::needs_array_len(u1 tag) {
  44   return (tag == multi_branch_data_tag) || (tag == arg_info_data_tag);
  45 }
  46 
  47 // Perform generic initialization of the data.  More specific
  48 // initialization occurs in overrides of ProfileData::post_initialize.
  49 void DataLayout::initialize(u1 tag, u2 bci, int cell_count) {
  50   _header._bits = (intptr_t)0;
  51   _header._struct._tag = tag;
  52   _header._struct._bci = bci;
  53   for (int i = 0; i < cell_count; i++) {
  54     set_cell_at(i, (intptr_t)0);
  55   }
  56   if (needs_array_len(tag)) {
  57     set_cell_at(ArrayData::array_len_off_set, cell_count - 1); // -1 for header.
  58   }
  59   if (tag == call_type_data_tag) {
  60     CallTypeData::initialize(this, cell_count);
  61   } else if (tag == virtual_call_type_data_tag) {
  62     VirtualCallTypeData::initialize(this, cell_count);
  63   }
  64 }
  65 
  66 void DataLayout::clean_weak_klass_links(BoolObjectClosure* cl) {
  67   ResourceMark m;
  68   data_in()->clean_weak_klass_links(cl);
  69 }
  70 
  71 
  72 // ==================================================================
  73 // ProfileData
  74 //
  75 // A ProfileData object is created to refer to a section of profiling
  76 // data in a structured way.
  77 
  78 // Constructor for invalid ProfileData.
  79 ProfileData::ProfileData() {
  80   _data = NULL;
  81 }
  82 
  83 #ifndef PRODUCT
  84 void ProfileData::print_shared(outputStream* st, const char* name) const {
  85   st->print("bci: %d", bci());
  86   st->fill_to(tab_width_one);
  87   st->print("%s", name);
  88   tab(st);
  89   int trap = trap_state();
  90   if (trap != 0) {
  91     char buf[100];
  92     st->print("trap(%s) ", Deoptimization::format_trap_state(buf, sizeof(buf), trap));
  93   }
  94   int flags = data()->flags();
  95   if (flags != 0)
  96     st->print("flags(%d) ", flags);
  97 }
  98 
  99 void ProfileData::tab(outputStream* st, bool first) const {
 100   st->fill_to(first ? tab_width_one : tab_width_two);
 101 }
 102 #endif // !PRODUCT
 103 
 104 // ==================================================================
 105 // BitData
 106 //
 107 // A BitData corresponds to a one-bit flag.  This is used to indicate
 108 // whether a checkcast bytecode has seen a null value.
 109 
 110 
 111 #ifndef PRODUCT
 112 void BitData::print_data_on(outputStream* st) const {
 113   print_shared(st, "BitData");
 114 }
 115 #endif // !PRODUCT
 116 
 117 // ==================================================================
 118 // CounterData
 119 //
 120 // A CounterData corresponds to a simple counter.
 121 
 122 #ifndef PRODUCT
 123 void CounterData::print_data_on(outputStream* st) const {
 124   print_shared(st, "CounterData");
 125   st->print_cr("count(%u)", count());
 126 }
 127 #endif // !PRODUCT
 128 
 129 // ==================================================================
 130 // JumpData
 131 //
 132 // A JumpData is used to access profiling information for a direct
 133 // branch.  It is a counter, used for counting the number of branches,
 134 // plus a data displacement, used for realigning the data pointer to
 135 // the corresponding target bci.
 136 
 137 void JumpData::post_initialize(BytecodeStream* stream, MethodData* mdo) {
 138   assert(stream->bci() == bci(), "wrong pos");
 139   int target;
 140   Bytecodes::Code c = stream->code();
 141   if (c == Bytecodes::_goto_w || c == Bytecodes::_jsr_w) {
 142     target = stream->dest_w();
 143   } else {
 144     target = stream->dest();
 145   }
 146   int my_di = mdo->dp_to_di(dp());
 147   int target_di = mdo->bci_to_di(target);
 148   int offset = target_di - my_di;
 149   set_displacement(offset);
 150 }
 151 
 152 #ifndef PRODUCT
 153 void JumpData::print_data_on(outputStream* st) const {
 154   print_shared(st, "JumpData");
 155   st->print_cr("taken(%u) displacement(%d)", taken(), displacement());
 156 }
 157 #endif // !PRODUCT
 158 
 159 int TypeStackSlotEntries::compute_cell_count(BytecodeStream* stream) {
 160   int max = TypeProfileArgsLimit;
 161   assert(Bytecodes::is_invoke(stream->code()), "should be invoke");
 162   Bytecode_invoke inv(stream->method(), stream->bci());
 163   
 164   ResourceMark rm;
 165   SignatureStream ss(inv.signature());
 166   int args_count = MIN2(ss.reference_parameter_count(), max);
 167 
 168   return args_count * per_arg_cell_count + (args_count > 0 ? header_cell_count() : 0);
 169 }
 170 
 171 class ArgumentOffsetComputer : public SignatureInfo {
 172 private:
 173   int _max;
 174   GrowableArray<int> _offsets;
 175 
 176   void set(int size, BasicType type) { _size += size; }
 177   void do_object(int begin, int end) {
 178     if (_offsets.length() < _max) {
 179       _offsets.push(_size);
 180     }
 181     SignatureInfo::do_object(begin, end);
 182   }
 183   void do_array (int begin, int end) {
 184     if (_offsets.length() < _max) {
 185       _offsets.push(_size);
 186     }
 187     SignatureInfo::do_array(begin, end);
 188   }
 189 
 190 public:
 191   ArgumentOffsetComputer(Symbol* signature, int max)
 192     : SignatureInfo(signature), _max(max), _offsets(Thread::current(), max) {
 193   }
 194 
 195   int total() { lazy_iterate_parameters(); return _size; }
 196 
 197   int off_at(int i) const { return _offsets.at(i); }
 198 };
 199 
 200 void TypeStackSlotEntries::post_initialize(BytecodeStream* stream) {
 201   ResourceMark rm;
 202 
 203   assert(Bytecodes::is_invoke(stream->code()), "should be invoke");
 204   Bytecode_invoke inv(stream->method(), stream->bci());
 205 
 206 #ifdef ASSERT
 207   SignatureStream ss(inv.signature());
 208   int count = MIN2(ss.reference_parameter_count(), TypeProfileArgsLimit);
 209   assert(count > 0, "room for args type but none found?");
 210   check_number_of_arguments(count);
 211 #endif
 212   
 213   int start = 0;
 214   ArgumentOffsetComputer aos(inv.signature(), number_of_arguments()-start);
 215   aos.total();
 216   bool has_receiver = inv.has_receiver();
 217   for (int i = start; i < number_of_arguments(); i++) {
 218     set_stack_slot(i, aos.off_at(i-start) + (has_receiver ? 1 : 0));
 219     set_type(i, type_none());
 220   }
 221 }
 222 
 223 bool TypeEntries::is_loader_alive(BoolObjectClosure* is_alive_cl, intptr_t p) {
 224   return !is_type_none(p) &&
 225     !((Klass*)klass_part(p))->is_loader_alive(is_alive_cl);
 226 }
 227 
 228 void TypeStackSlotEntries::clean_weak_klass_links(BoolObjectClosure* is_alive_cl) {
 229   for (int i = 0; i < number_of_arguments(); i++) {
 230     intptr_t p = type(i);
 231     if (is_loader_alive(is_alive_cl, p)) {
 232       set_type(i, type_none());
 233     }
 234   }
 235 }
 236 
 237 bool TypeStackSlotEntries::arguments_profiling_enabled() {
 238   return MethodData::profile_arguments();
 239 }
 240 
 241 #ifndef PRODUCT
 242 void TypeEntries::print_klass(outputStream* st, intptr_t k) {
 243   if (is_type_none(k)) {
 244     st->print("none");
 245   } else if (is_type_unknown(k)) {
 246     st->print("unknown");
 247   } else {
 248     valid_klass(k)->print_value_on(st);
 249   }
 250   if (was_null_seen(k)) {
 251     st->print(" (null seen)");
 252   }
 253 }
 254 
 255 void TypeStackSlotEntries::print_data_on(outputStream* st) const {
 256   _pd->tab(st, true);
 257   st->print("argument types");
 258   for (int i = 0; i < number_of_arguments(); i++) {
 259     _pd->tab(st);
 260     st->print("%d: stack(%u) ", i, stack_slot(i));
 261     print_klass(st, type(i));
 262     st->cr();
 263   }
 264 }
 265 
 266 void CallTypeData::print_data_on(outputStream* st) const {
 267   CounterData::print_data_on(st);
 268   _args.print_data_on(st);
 269 }
 270 
 271 void VirtualCallTypeData::print_data_on(outputStream* st) const {
 272   VirtualCallData::print_data_on(st);
 273   _args.print_data_on(st);
 274 }
 275 #endif
 276 
 277 // ==================================================================
 278 // ReceiverTypeData
 279 //
 280 // A ReceiverTypeData is used to access profiling information about a
 281 // dynamic type check.  It consists of a counter which counts the total times
 282 // that the check is reached, and a series of (Klass*, count) pairs
 283 // which are used to store a type profile for the receiver of the check.
 284 
 285 void ReceiverTypeData::clean_weak_klass_links(BoolObjectClosure* is_alive_cl) {
 286     for (uint row = 0; row < row_limit(); row++) {
 287     Klass* p = receiver(row);
 288     if (p != NULL && !p->is_loader_alive(is_alive_cl)) {
 289       clear_row(row);
 290     }
 291   }
 292 }
 293 
 294 #ifndef PRODUCT
 295 void ReceiverTypeData::print_receiver_data_on(outputStream* st) const {
 296   uint row;
 297   int entries = 0;
 298   for (row = 0; row < row_limit(); row++) {
 299     if (receiver(row) != NULL)  entries++;
 300   }
 301   st->print_cr("count(%u) entries(%u)", count(), entries);
 302   int total = count();
 303   for (row = 0; row < row_limit(); row++) {
 304     if (receiver(row) != NULL) {
 305       total += receiver_count(row);
 306     }
 307   }
 308   for (row = 0; row < row_limit(); row++) {
 309     if (receiver(row) != NULL) {
 310       tab(st);
 311       receiver(row)->print_value_on(st);
 312       st->print_cr("(%u %4.2f)", receiver_count(row), (float) receiver_count(row) / (float) total);
 313     }
 314   }
 315 }
 316 void ReceiverTypeData::print_data_on(outputStream* st) const {
 317   print_shared(st, "ReceiverTypeData");
 318   print_receiver_data_on(st);
 319 }
 320 void VirtualCallData::print_data_on(outputStream* st) const {
 321   print_shared(st, "VirtualCallData");
 322   print_receiver_data_on(st);
 323 }
 324 #endif // !PRODUCT
 325 
 326 // ==================================================================
 327 // RetData
 328 //
 329 // A RetData is used to access profiling information for a ret bytecode.
 330 // It is composed of a count of the number of times that the ret has
 331 // been executed, followed by a series of triples of the form
 332 // (bci, count, di) which count the number of times that some bci was the
 333 // target of the ret and cache a corresponding displacement.
 334 
 335 void RetData::post_initialize(BytecodeStream* stream, MethodData* mdo) {
 336   for (uint row = 0; row < row_limit(); row++) {
 337     set_bci_displacement(row, -1);
 338     set_bci(row, no_bci);
 339   }
 340   // release so other threads see a consistent state.  bci is used as
 341   // a valid flag for bci_displacement.
 342   OrderAccess::release();
 343 }
 344 
 345 // This routine needs to atomically update the RetData structure, so the
 346 // caller needs to hold the RetData_lock before it gets here.  Since taking
 347 // the lock can block (and allow GC) and since RetData is a ProfileData is a
 348 // wrapper around a derived oop, taking the lock in _this_ method will
 349 // basically cause the 'this' pointer's _data field to contain junk after the
 350 // lock.  We require the caller to take the lock before making the ProfileData
 351 // structure.  Currently the only caller is InterpreterRuntime::update_mdp_for_ret
 352 address RetData::fixup_ret(int return_bci, MethodData* h_mdo) {
 353   // First find the mdp which corresponds to the return bci.
 354   address mdp = h_mdo->bci_to_dp(return_bci);
 355 
 356   // Now check to see if any of the cache slots are open.
 357   for (uint row = 0; row < row_limit(); row++) {
 358     if (bci(row) == no_bci) {
 359       set_bci_displacement(row, mdp - dp());
 360       set_bci_count(row, DataLayout::counter_increment);
 361       // Barrier to ensure displacement is written before the bci; allows
 362       // the interpreter to read displacement without fear of race condition.
 363       release_set_bci(row, return_bci);
 364       break;
 365     }
 366   }
 367   return mdp;
 368 }
 369 
 370 
 371 #ifndef PRODUCT
 372 void RetData::print_data_on(outputStream* st) const {
 373   print_shared(st, "RetData");
 374   uint row;
 375   int entries = 0;
 376   for (row = 0; row < row_limit(); row++) {
 377     if (bci(row) != no_bci)  entries++;
 378   }
 379   st->print_cr("count(%u) entries(%u)", count(), entries);
 380   for (row = 0; row < row_limit(); row++) {
 381     if (bci(row) != no_bci) {
 382       tab(st);
 383       st->print_cr("bci(%d: count(%u) displacement(%d))",
 384                    bci(row), bci_count(row), bci_displacement(row));
 385     }
 386   }
 387 }
 388 #endif // !PRODUCT
 389 
 390 // ==================================================================
 391 // BranchData
 392 //
 393 // A BranchData is used to access profiling data for a two-way branch.
 394 // It consists of taken and not_taken counts as well as a data displacement
 395 // for the taken case.
 396 
 397 void BranchData::post_initialize(BytecodeStream* stream, MethodData* mdo) {
 398   assert(stream->bci() == bci(), "wrong pos");
 399   int target = stream->dest();
 400   int my_di = mdo->dp_to_di(dp());
 401   int target_di = mdo->bci_to_di(target);
 402   int offset = target_di - my_di;
 403   set_displacement(offset);
 404 }
 405 
 406 #ifndef PRODUCT
 407 void BranchData::print_data_on(outputStream* st) const {
 408   print_shared(st, "BranchData");
 409   st->print_cr("taken(%u) displacement(%d)",
 410                taken(), displacement());
 411   tab(st);
 412   st->print_cr("not taken(%u)", not_taken());
 413 }
 414 #endif
 415 
 416 // ==================================================================
 417 // MultiBranchData
 418 //
 419 // A MultiBranchData is used to access profiling information for
 420 // a multi-way branch (*switch bytecodes).  It consists of a series
 421 // of (count, displacement) pairs, which count the number of times each
 422 // case was taken and specify the data displacment for each branch target.
 423 
 424 int MultiBranchData::compute_cell_count(BytecodeStream* stream) {
 425   int cell_count = 0;
 426   if (stream->code() == Bytecodes::_tableswitch) {
 427     Bytecode_tableswitch sw(stream->method()(), stream->bcp());
 428     cell_count = 1 + per_case_cell_count * (1 + sw.length()); // 1 for default
 429   } else {
 430     Bytecode_lookupswitch sw(stream->method()(), stream->bcp());
 431     cell_count = 1 + per_case_cell_count * (sw.number_of_pairs() + 1); // 1 for default
 432   }
 433   return cell_count;
 434 }
 435 
 436 void MultiBranchData::post_initialize(BytecodeStream* stream,
 437                                       MethodData* mdo) {
 438   assert(stream->bci() == bci(), "wrong pos");
 439   int target;
 440   int my_di;
 441   int target_di;
 442   int offset;
 443   if (stream->code() == Bytecodes::_tableswitch) {
 444     Bytecode_tableswitch sw(stream->method()(), stream->bcp());
 445     int len = sw.length();
 446     assert(array_len() == per_case_cell_count * (len + 1), "wrong len");
 447     for (int count = 0; count < len; count++) {
 448       target = sw.dest_offset_at(count) + bci();
 449       my_di = mdo->dp_to_di(dp());
 450       target_di = mdo->bci_to_di(target);
 451       offset = target_di - my_di;
 452       set_displacement_at(count, offset);
 453     }
 454     target = sw.default_offset() + bci();
 455     my_di = mdo->dp_to_di(dp());
 456     target_di = mdo->bci_to_di(target);
 457     offset = target_di - my_di;
 458     set_default_displacement(offset);
 459 
 460   } else {
 461     Bytecode_lookupswitch sw(stream->method()(), stream->bcp());
 462     int npairs = sw.number_of_pairs();
 463     assert(array_len() == per_case_cell_count * (npairs + 1), "wrong len");
 464     for (int count = 0; count < npairs; count++) {
 465       LookupswitchPair pair = sw.pair_at(count);
 466       target = pair.offset() + bci();
 467       my_di = mdo->dp_to_di(dp());
 468       target_di = mdo->bci_to_di(target);
 469       offset = target_di - my_di;
 470       set_displacement_at(count, offset);
 471     }
 472     target = sw.default_offset() + bci();
 473     my_di = mdo->dp_to_di(dp());
 474     target_di = mdo->bci_to_di(target);
 475     offset = target_di - my_di;
 476     set_default_displacement(offset);
 477   }
 478 }
 479 
 480 #ifndef PRODUCT
 481 void MultiBranchData::print_data_on(outputStream* st) const {
 482   print_shared(st, "MultiBranchData");
 483   st->print_cr("default_count(%u) displacement(%d)",
 484                default_count(), default_displacement());
 485   int cases = number_of_cases();
 486   for (int i = 0; i < cases; i++) {
 487     tab(st);
 488     st->print_cr("count(%u) displacement(%d)",
 489                  count_at(i), displacement_at(i));
 490   }
 491 }
 492 #endif
 493 
 494 #ifndef PRODUCT
 495 void ArgInfoData::print_data_on(outputStream* st) const {
 496   print_shared(st, "ArgInfoData");
 497   int nargs = number_of_args();
 498   for (int i = 0; i < nargs; i++) {
 499     st->print("  0x%x", arg_modified(i));
 500   }
 501   st->cr();
 502 }
 503 
 504 #endif
 505 // ==================================================================
 506 // MethodData*
 507 //
 508 // A MethodData* holds information which has been collected about
 509 // a method.
 510 
 511 MethodData* MethodData::allocate(ClassLoaderData* loader_data, methodHandle method, TRAPS) {
 512   int size = MethodData::compute_allocation_size_in_words(method);
 513 
 514   return new (loader_data, size, false, MetaspaceObj::MethodDataType, THREAD)
 515     MethodData(method(), size, CHECK_NULL);
 516 }
 517 
 518 int MethodData::bytecode_cell_count(Bytecodes::Code code) {
 519 #if defined(COMPILER1) && !defined(COMPILER2)
 520   return no_profile_data;
 521 #else
 522   switch (code) {
 523   case Bytecodes::_checkcast:
 524   case Bytecodes::_instanceof:
 525   case Bytecodes::_aastore:
 526     if (TypeProfileCasts) {
 527       return ReceiverTypeData::static_cell_count();
 528     } else {
 529       return BitData::static_cell_count();
 530     }
 531   case Bytecodes::_invokespecial:
 532   case Bytecodes::_invokestatic:
 533     if (MethodData::profile_arguments()) {
 534       return variable_cell_count;
 535     } else {
 536       return CounterData::static_cell_count();
 537     }
 538   case Bytecodes::_goto:
 539   case Bytecodes::_goto_w:
 540   case Bytecodes::_jsr:
 541   case Bytecodes::_jsr_w:
 542     return JumpData::static_cell_count();
 543   case Bytecodes::_invokevirtual:
 544   case Bytecodes::_invokeinterface:
 545     if (MethodData::profile_arguments()) {
 546       return variable_cell_count;
 547     } else {
 548       return VirtualCallData::static_cell_count();
 549     }
 550   case Bytecodes::_invokedynamic:
 551     if (MethodData::profile_arguments()) {
 552       return variable_cell_count;
 553     } else {
 554       return CounterData::static_cell_count();
 555     }
 556   case Bytecodes::_ret:
 557     return RetData::static_cell_count();
 558   case Bytecodes::_ifeq:
 559   case Bytecodes::_ifne:
 560   case Bytecodes::_iflt:
 561   case Bytecodes::_ifge:
 562   case Bytecodes::_ifgt:
 563   case Bytecodes::_ifle:
 564   case Bytecodes::_if_icmpeq:
 565   case Bytecodes::_if_icmpne:
 566   case Bytecodes::_if_icmplt:
 567   case Bytecodes::_if_icmpge:
 568   case Bytecodes::_if_icmpgt:
 569   case Bytecodes::_if_icmple:
 570   case Bytecodes::_if_acmpeq:
 571   case Bytecodes::_if_acmpne:
 572   case Bytecodes::_ifnull:
 573   case Bytecodes::_ifnonnull:
 574     return BranchData::static_cell_count();
 575   case Bytecodes::_lookupswitch:
 576   case Bytecodes::_tableswitch:
 577     return variable_cell_count;
 578   }
 579   return no_profile_data;
 580 #endif
 581 }
 582 
 583 // Compute the size of the profiling information corresponding to
 584 // the current bytecode.
 585 int MethodData::compute_data_size(BytecodeStream* stream) {
 586   int cell_count = bytecode_cell_count(stream->code());
 587   if (cell_count == no_profile_data) {
 588     return 0;
 589   }
 590   if (cell_count == variable_cell_count) {
 591     switch (stream->code()) {
 592     case Bytecodes::_lookupswitch:
 593     case Bytecodes::_tableswitch:
 594       cell_count = MultiBranchData::compute_cell_count(stream);
 595       break;
 596     case Bytecodes::_invokespecial:
 597     case Bytecodes::_invokestatic:
 598     case Bytecodes::_invokedynamic:
 599       assert(MethodData::profile_arguments(), "should be collecting args profile");
 600       if (profile_arguments_for_invoke(stream->method(), stream->bci())) {
 601         cell_count = CallTypeData::compute_cell_count(stream);
 602       } else {
 603         cell_count = CounterData::static_cell_count();
 604       }
 605       break;
 606     case Bytecodes::_invokevirtual:
 607     case Bytecodes::_invokeinterface: {
 608       assert(MethodData::profile_arguments(), "should be collecting args profile");
 609       if (profile_arguments_for_invoke(stream->method(), stream->bci())) {
 610         cell_count = VirtualCallTypeData::compute_cell_count(stream);
 611       } else {
 612         cell_count = VirtualCallData::static_cell_count();
 613       }
 614       break;
 615     }
 616     default:
 617       fatal("unexpected bytecode for var length profile data");
 618     }
 619   }
 620   // Note:  cell_count might be zero, meaning that there is just
 621   //        a DataLayout header, with no extra cells.
 622   assert(cell_count >= 0, "sanity");
 623   return DataLayout::compute_size_in_bytes(cell_count);
 624 }
 625 
 626 int MethodData::compute_extra_data_count(int data_size, int empty_bc_count) {
 627   if (ProfileTraps) {
 628     // Assume that up to 3% of BCIs with no MDP will need to allocate one.
 629     int extra_data_count = (uint)(empty_bc_count * 3) / 128 + 1;
 630     // If the method is large, let the extra BCIs grow numerous (to ~1%).
 631     int one_percent_of_data
 632       = (uint)data_size / (DataLayout::header_size_in_bytes()*128);
 633     if (extra_data_count < one_percent_of_data)
 634       extra_data_count = one_percent_of_data;
 635     if (extra_data_count > empty_bc_count)
 636       extra_data_count = empty_bc_count;  // no need for more
 637     return extra_data_count;
 638   } else {
 639     return 0;
 640   }
 641 }
 642 
 643 // Compute the size of the MethodData* necessary to store
 644 // profiling information about a given method.  Size is in bytes.
 645 int MethodData::compute_allocation_size_in_bytes(methodHandle method) {
 646   int data_size = 0;
 647   BytecodeStream stream(method);
 648   Bytecodes::Code c;
 649   int empty_bc_count = 0;  // number of bytecodes lacking data
 650   while ((c = stream.next()) >= 0) {
 651     int size_in_bytes = compute_data_size(&stream);
 652     data_size += size_in_bytes;
 653     if (size_in_bytes == 0)  empty_bc_count += 1;
 654   }
 655   int object_size = in_bytes(data_offset()) + data_size;
 656 
 657   // Add some extra DataLayout cells (at least one) to track stray traps.
 658   int extra_data_count = compute_extra_data_count(data_size, empty_bc_count);
 659   object_size += extra_data_count * DataLayout::compute_size_in_bytes(0);
 660 
 661   // Add a cell to record information about modified arguments.
 662   int arg_size = method->size_of_parameters();
 663   object_size += DataLayout::compute_size_in_bytes(arg_size+1);
 664 
 665   return object_size;
 666 }
 667 
 668 // Compute the size of the MethodData* necessary to store
 669 // profiling information about a given method.  Size is in words
 670 int MethodData::compute_allocation_size_in_words(methodHandle method) {
 671   int byte_size = compute_allocation_size_in_bytes(method);
 672   int word_size = align_size_up(byte_size, BytesPerWord) / BytesPerWord;
 673   return align_object_size(word_size);
 674 }
 675 
 676 // Initialize an individual data segment.  Returns the size of
 677 // the segment in bytes.
 678 int MethodData::initialize_data(BytecodeStream* stream,
 679                                        int data_index) {
 680 #if defined(COMPILER1) && !defined(COMPILER2)
 681   return 0;
 682 #else
 683   int cell_count = -1;
 684   int tag = DataLayout::no_tag;
 685   DataLayout* data_layout = data_layout_at(data_index);
 686   Bytecodes::Code c = stream->code();
 687   switch (c) {
 688   case Bytecodes::_checkcast:
 689   case Bytecodes::_instanceof:
 690   case Bytecodes::_aastore:
 691     if (TypeProfileCasts) {
 692       cell_count = ReceiverTypeData::static_cell_count();
 693       tag = DataLayout::receiver_type_data_tag;
 694     } else {
 695       cell_count = BitData::static_cell_count();
 696       tag = DataLayout::bit_data_tag;
 697     }
 698     break;
 699   case Bytecodes::_invokespecial:
 700   case Bytecodes::_invokestatic: {
 701     int counter_data_cell_count = CounterData::static_cell_count();
 702     if (profile_arguments_for_invoke(stream->method(), stream->bci())) {
 703       cell_count = CallTypeData::compute_cell_count(stream);
 704     } else {
 705       cell_count = counter_data_cell_count;
 706     }
 707     if (cell_count > counter_data_cell_count) {
 708       tag = DataLayout::call_type_data_tag;
 709     } else {
 710       tag = DataLayout::counter_data_tag;
 711     }
 712     break;
 713   }
 714   case Bytecodes::_goto:
 715   case Bytecodes::_goto_w:
 716   case Bytecodes::_jsr:
 717   case Bytecodes::_jsr_w:
 718     cell_count = JumpData::static_cell_count();
 719     tag = DataLayout::jump_data_tag;
 720     break;
 721   case Bytecodes::_invokevirtual:
 722   case Bytecodes::_invokeinterface: {
 723     int virtual_call_data_cell_count = VirtualCallData::static_cell_count();
 724     if (profile_arguments_for_invoke(stream->method(), stream->bci())) {
 725       cell_count = VirtualCallTypeData::compute_cell_count(stream);
 726     } else {
 727       cell_count = virtual_call_data_cell_count;
 728     }
 729     if (cell_count > virtual_call_data_cell_count) {
 730       tag = DataLayout::virtual_call_type_data_tag;
 731     } else {
 732       tag = DataLayout::virtual_call_data_tag;
 733     }
 734     break;
 735   }
 736   case Bytecodes::_invokedynamic: {
 737     // %%% should make a type profile for any invokedynamic that takes a ref argument
 738     int counter_data_cell_count = CounterData::static_cell_count();
 739     if (profile_arguments_for_invoke(stream->method(), stream->bci())) {
 740       cell_count = CallTypeData::compute_cell_count(stream);
 741     } else {
 742       cell_count = counter_data_cell_count;
 743     }
 744     if (cell_count > counter_data_cell_count) {
 745       tag = DataLayout::call_type_data_tag;
 746     } else {
 747       tag = DataLayout::counter_data_tag;
 748     }
 749     break;
 750   }
 751   case Bytecodes::_ret:
 752     cell_count = RetData::static_cell_count();
 753     tag = DataLayout::ret_data_tag;
 754     break;
 755   case Bytecodes::_ifeq:
 756   case Bytecodes::_ifne:
 757   case Bytecodes::_iflt:
 758   case Bytecodes::_ifge:
 759   case Bytecodes::_ifgt:
 760   case Bytecodes::_ifle:
 761   case Bytecodes::_if_icmpeq:
 762   case Bytecodes::_if_icmpne:
 763   case Bytecodes::_if_icmplt:
 764   case Bytecodes::_if_icmpge:
 765   case Bytecodes::_if_icmpgt:
 766   case Bytecodes::_if_icmple:
 767   case Bytecodes::_if_acmpeq:
 768   case Bytecodes::_if_acmpne:
 769   case Bytecodes::_ifnull:
 770   case Bytecodes::_ifnonnull:
 771     cell_count = BranchData::static_cell_count();
 772     tag = DataLayout::branch_data_tag;
 773     break;
 774   case Bytecodes::_lookupswitch:
 775   case Bytecodes::_tableswitch:
 776     cell_count = MultiBranchData::compute_cell_count(stream);
 777     tag = DataLayout::multi_branch_data_tag;
 778     break;
 779   }
 780   assert(tag == DataLayout::multi_branch_data_tag ||
 781          (MethodData::profile_arguments() &&
 782           (tag == DataLayout::call_type_data_tag ||
 783            tag == DataLayout::counter_data_tag ||
 784            tag == DataLayout::virtual_call_type_data_tag ||
 785            tag == DataLayout::virtual_call_data_tag)) ||
 786          cell_count == bytecode_cell_count(c), "cell counts must agree");
 787   if (cell_count >= 0) {
 788     assert(tag != DataLayout::no_tag, "bad tag");
 789     assert(bytecode_has_profile(c), "agree w/ BHP");
 790     data_layout->initialize(tag, stream->bci(), cell_count);
 791     return DataLayout::compute_size_in_bytes(cell_count);
 792   } else {
 793     assert(!bytecode_has_profile(c), "agree w/ !BHP");
 794     return 0;
 795   }
 796 #endif
 797 }
 798 
 799 // Get the data at an arbitrary (sort of) data index.
 800 ProfileData* MethodData::data_at(int data_index) const {
 801   if (out_of_bounds(data_index)) {
 802     return NULL;
 803   }
 804   DataLayout* data_layout = data_layout_at(data_index);
 805   return data_layout->data_in();
 806 }
 807 
 808 ProfileData* DataLayout::data_in() {
 809   switch (tag()) {
 810   case DataLayout::no_tag:
 811   default:
 812     ShouldNotReachHere();
 813     return NULL;
 814   case DataLayout::bit_data_tag:
 815     return new BitData(this);
 816   case DataLayout::counter_data_tag:
 817     return new CounterData(this);
 818   case DataLayout::jump_data_tag:
 819     return new JumpData(this);
 820   case DataLayout::receiver_type_data_tag:
 821     return new ReceiverTypeData(this);
 822   case DataLayout::virtual_call_data_tag:
 823     return new VirtualCallData(this);
 824   case DataLayout::ret_data_tag:
 825     return new RetData(this);
 826   case DataLayout::branch_data_tag:
 827     return new BranchData(this);
 828   case DataLayout::multi_branch_data_tag:
 829     return new MultiBranchData(this);
 830   case DataLayout::arg_info_data_tag:
 831     return new ArgInfoData(this);
 832   case DataLayout::call_type_data_tag:
 833     return new CallTypeData(this);
 834   case DataLayout::virtual_call_type_data_tag:
 835     return new VirtualCallTypeData(this);
 836   };
 837 }
 838 
 839 // Iteration over data.
 840 ProfileData* MethodData::next_data(ProfileData* current) const {
 841   int current_index = dp_to_di(current->dp());
 842   int next_index = current_index + current->size_in_bytes();
 843   ProfileData* next = data_at(next_index);
 844   return next;
 845 }
 846 
 847 // Give each of the data entries a chance to perform specific
 848 // data initialization.
 849 void MethodData::post_initialize(BytecodeStream* stream) {
 850   ResourceMark rm;
 851   ProfileData* data;
 852   for (data = first_data(); is_valid(data); data = next_data(data)) {
 853     stream->set_start(data->bci());
 854     stream->next();
 855     data->post_initialize(stream, this);
 856   }
 857 }
 858 
 859 // Initialize the MethodData* corresponding to a given method.
 860 MethodData::MethodData(methodHandle method, int size, TRAPS) {
 861   No_Safepoint_Verifier no_safepoint;  // init function atomic wrt GC
 862   ResourceMark rm;
 863   // Set the method back-pointer.
 864   _method = method();
 865 
 866   init();
 867   set_creation_mileage(mileage_of(method()));
 868 
 869   // Go through the bytecodes and allocate and initialize the
 870   // corresponding data cells.
 871   int data_size = 0;
 872   int empty_bc_count = 0;  // number of bytecodes lacking data
 873   _data[0] = 0;  // apparently not set below.
 874   BytecodeStream stream(method);
 875   Bytecodes::Code c;
 876   while ((c = stream.next()) >= 0) {
 877     int size_in_bytes = initialize_data(&stream, data_size);
 878     data_size += size_in_bytes;
 879     if (size_in_bytes == 0)  empty_bc_count += 1;
 880   }
 881   _data_size = data_size;
 882   int object_size = in_bytes(data_offset()) + data_size;
 883 
 884   // Add some extra DataLayout cells (at least one) to track stray traps.
 885   int extra_data_count = compute_extra_data_count(data_size, empty_bc_count);
 886   int extra_size = extra_data_count * DataLayout::compute_size_in_bytes(0);
 887 
 888   // Add a cell to record information about modified arguments.
 889   // Set up _args_modified array after traps cells so that
 890   // the code for traps cells works.
 891   DataLayout *dp = data_layout_at(data_size + extra_size);
 892 
 893   int arg_size = method->size_of_parameters();
 894   dp->initialize(DataLayout::arg_info_data_tag, 0, arg_size+1);
 895 
 896   object_size += extra_size + DataLayout::compute_size_in_bytes(arg_size+1);
 897 
 898   // Set an initial hint. Don't use set_hint_di() because
 899   // first_di() may be out of bounds if data_size is 0.
 900   // In that situation, _hint_di is never used, but at
 901   // least well-defined.
 902   _hint_di = first_di();
 903 
 904   post_initialize(&stream);
 905 
 906   set_size(object_size);
 907 }
 908 
 909 void MethodData::init() {
 910   _invocation_counter.init();
 911   _backedge_counter.init();
 912   _invocation_counter_start = 0;
 913   _backedge_counter_start = 0;
 914   _num_loops = 0;
 915   _num_blocks = 0;
 916   _highest_comp_level = 0;
 917   _highest_osr_comp_level = 0;
 918   _would_profile = true;
 919 
 920   // Initialize flags and trap history.
 921   _nof_decompiles = 0;
 922   _nof_overflow_recompiles = 0;
 923   _nof_overflow_traps = 0;
 924   clear_escape_info();
 925   assert(sizeof(_trap_hist) % sizeof(HeapWord) == 0, "align");
 926   Copy::zero_to_words((HeapWord*) &_trap_hist,
 927                       sizeof(_trap_hist) / sizeof(HeapWord));
 928 }
 929 
 930 // Get a measure of how much mileage the method has on it.
 931 int MethodData::mileage_of(Method* method) {
 932   int mileage = 0;
 933   if (TieredCompilation) {
 934     mileage = MAX2(method->invocation_count(), method->backedge_count());
 935   } else {
 936     int iic = method->interpreter_invocation_count();
 937     if (mileage < iic)  mileage = iic;
 938     MethodCounters* mcs = method->method_counters();
 939     if (mcs != NULL) {
 940       InvocationCounter* ic = mcs->invocation_counter();
 941       InvocationCounter* bc = mcs->backedge_counter();
 942       int icval = ic->count();
 943       if (ic->carry()) icval += CompileThreshold;
 944       if (mileage < icval)  mileage = icval;
 945       int bcval = bc->count();
 946       if (bc->carry()) bcval += CompileThreshold;
 947       if (mileage < bcval)  mileage = bcval;
 948     }
 949   }
 950   return mileage;
 951 }
 952 
 953 bool MethodData::is_mature() const {
 954   return CompilationPolicy::policy()->is_mature(_method);
 955 }
 956 
 957 // Translate a bci to its corresponding data index (di).
 958 address MethodData::bci_to_dp(int bci) {
 959   ResourceMark rm;
 960   ProfileData* data = data_before(bci);
 961   ProfileData* prev = NULL;
 962   for ( ; is_valid(data); data = next_data(data)) {
 963     if (data->bci() >= bci) {
 964       if (data->bci() == bci)  set_hint_di(dp_to_di(data->dp()));
 965       else if (prev != NULL)   set_hint_di(dp_to_di(prev->dp()));
 966       return data->dp();
 967     }
 968     prev = data;
 969   }
 970   return (address)limit_data_position();
 971 }
 972 
 973 // Translate a bci to its corresponding data, or NULL.
 974 ProfileData* MethodData::bci_to_data(int bci) {
 975   ProfileData* data = data_before(bci);
 976   for ( ; is_valid(data); data = next_data(data)) {
 977     if (data->bci() == bci) {
 978       set_hint_di(dp_to_di(data->dp()));
 979       return data;
 980     } else if (data->bci() > bci) {
 981       break;
 982     }
 983   }
 984   return bci_to_extra_data(bci, false);
 985 }
 986 
 987 // Translate a bci to its corresponding extra data, or NULL.
 988 ProfileData* MethodData::bci_to_extra_data(int bci, bool create_if_missing) {
 989   DataLayout* dp    = extra_data_base();
 990   DataLayout* end   = extra_data_limit();
 991   DataLayout* avail = NULL;
 992   for (; dp < end; dp = next_extra(dp)) {
 993     // No need for "OrderAccess::load_acquire" ops,
 994     // since the data structure is monotonic.
 995     if (dp->tag() == DataLayout::no_tag)  break;
 996     if (dp->tag() == DataLayout::arg_info_data_tag) {
 997       dp = end; // ArgInfoData is at the end of extra data section.
 998       break;
 999     }
1000     if (dp->bci() == bci) {
1001       assert(dp->tag() == DataLayout::bit_data_tag, "sane");
1002       return new BitData(dp);
1003     }
1004   }
1005   if (create_if_missing && dp < end) {
1006     // Allocate this one.  There is no mutual exclusion,
1007     // so two threads could allocate different BCIs to the
1008     // same data layout.  This means these extra data
1009     // records, like most other MDO contents, must not be
1010     // trusted too much.
1011     DataLayout temp;
1012     temp.initialize(DataLayout::bit_data_tag, bci, 0);
1013     dp->release_set_header(temp.header());
1014     assert(dp->tag() == DataLayout::bit_data_tag, "sane");
1015     //NO: assert(dp->bci() == bci, "no concurrent allocation");
1016     return new BitData(dp);
1017   }
1018   return NULL;
1019 }
1020 
1021 ArgInfoData *MethodData::arg_info() {
1022   DataLayout* dp    = extra_data_base();
1023   DataLayout* end   = extra_data_limit();
1024   for (; dp < end; dp = next_extra(dp)) {
1025     if (dp->tag() == DataLayout::arg_info_data_tag)
1026       return new ArgInfoData(dp);
1027   }
1028   return NULL;
1029 }
1030 
1031 // Printing
1032 
1033 #ifndef PRODUCT
1034 
1035 void MethodData::print_on(outputStream* st) const {
1036   assert(is_methodData(), "should be method data");
1037   st->print("method data for ");
1038   method()->print_value_on(st);
1039   st->cr();
1040   print_data_on(st);
1041 }
1042 
1043 #endif //PRODUCT
1044 
1045 void MethodData::print_value_on(outputStream* st) const {
1046   assert(is_methodData(), "should be method data");
1047   st->print("method data for ");
1048   method()->print_value_on(st);
1049 }
1050 
1051 #ifndef PRODUCT
1052 void MethodData::print_data_on(outputStream* st) const {
1053   ResourceMark rm;
1054   ProfileData* data = first_data();
1055   for ( ; is_valid(data); data = next_data(data)) {
1056     st->print("%d", dp_to_di(data->dp()));
1057     st->fill_to(6);
1058     data->print_data_on(st);
1059   }
1060   st->print_cr("--- Extra data:");
1061   DataLayout* dp    = extra_data_base();
1062   DataLayout* end   = extra_data_limit();
1063   for (; dp < end; dp = next_extra(dp)) {
1064     // No need for "OrderAccess::load_acquire" ops,
1065     // since the data structure is monotonic.
1066     if (dp->tag() == DataLayout::no_tag)  continue;
1067     if (dp->tag() == DataLayout::bit_data_tag) {
1068       data = new BitData(dp);
1069     } else {
1070       assert(dp->tag() == DataLayout::arg_info_data_tag, "must be BitData or ArgInfo");
1071       data = new ArgInfoData(dp);
1072       dp = end; // ArgInfoData is at the end of extra data section.
1073     }
1074     st->print("%d", dp_to_di(data->dp()));
1075     st->fill_to(6);
1076     data->print_data_on(st);
1077   }
1078 }
1079 #endif
1080 
1081 #if INCLUDE_SERVICES
1082 // Size Statistics
1083 void MethodData::collect_statistics(KlassSizeStats *sz) const {
1084   int n = sz->count(this);
1085   sz->_method_data_bytes += n;
1086   sz->_method_all_bytes += n;
1087   sz->_rw_bytes += n;
1088 }
1089 #endif // INCLUDE_SERVICES
1090 
1091 // Verification
1092 
1093 void MethodData::verify_on(outputStream* st) {
1094   guarantee(is_methodData(), "object must be method data");
1095   // guarantee(m->is_perm(), "should be in permspace");
1096   this->verify_data_on(st);
1097 }
1098 
1099 void MethodData::verify_data_on(outputStream* st) {
1100   NEEDS_CLEANUP;
1101   // not yet implemented.
1102 }
1103 
1104 bool MethodData::profile_jsr292(methodHandle m, int bci) {
1105   if (m->is_compiled_lambda_form()) {
1106     return true;
1107   }
1108 
1109   Bytecode_invoke inv(m , bci);
1110   return inv.is_invokedynamic() || inv.is_invokehandle();
1111 }
1112 
1113 int MethodData::profile_arguments_flag() {
1114   return TypeProfileLevel;
1115 }
1116 
1117 bool MethodData::profile_arguments() {
1118   return profile_arguments_flag() > no_type_profile && profile_arguments_flag() <= type_profile_all;
1119 }
1120 
1121 bool MethodData::profile_arguments_jsr292_only() {
1122   return profile_arguments_flag() == type_profile_jsr292;
1123 }
1124 
1125 bool MethodData::profile_all_arguments() {
1126   return profile_arguments_flag() == type_profile_all;
1127 }
1128 
1129 bool MethodData::profile_arguments_for_invoke(methodHandle m, int bci) {
1130   if (!profile_arguments()) {
1131     return false;
1132   }
1133   
1134   if (profile_all_arguments()) {
1135     return true;
1136   }
1137   
1138   assert(profile_arguments_jsr292_only(), "inconsistent");
1139   return profile_jsr292(m, bci);
1140 }
1141