1 /*
   2  * Copyright (c) 2005, 2015, 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 "ci/bcEscapeAnalyzer.hpp"
  27 #include "ci/ciConstant.hpp"
  28 #include "ci/ciField.hpp"
  29 #include "ci/ciMethodBlocks.hpp"
  30 #include "ci/ciStreams.hpp"
  31 #include "interpreter/bytecode.hpp"
  32 #include "oops/oop.inline.hpp"
  33 #include "utilities/bitMap.inline.hpp"
  34 
  35 
  36 
  37 #ifndef PRODUCT
  38   #define TRACE_BCEA(level, code)                                            \
  39     if (EstimateArgEscape && BCEATraceLevel >= level) {                        \
  40       code;                                                                  \
  41     }
  42 #else
  43   #define TRACE_BCEA(level, code)
  44 #endif
  45 
  46 // Maintain a map of which arguments a local variable or
  47 // stack slot may contain.  In addition to tracking
  48 // arguments, it tracks two special values, "allocated"
  49 // which represents any object allocated in the current
  50 // method, and "unknown" which is any other object.
  51 // Up to 30 arguments are handled, with the last one
  52 // representing summary information for any extra arguments
  53 class BCEscapeAnalyzer::ArgumentMap {
  54   uint  _bits;
  55   enum {MAXBIT = 29,
  56         ALLOCATED = 1,
  57         UNKNOWN = 2};
  58 
  59   uint int_to_bit(uint e) const {
  60     if (e > MAXBIT)
  61       e = MAXBIT;
  62     return (1 << (e + 2));
  63   }
  64 
  65 public:
  66   ArgumentMap()                         { _bits = 0;}
  67   void set_bits(uint bits)              { _bits = bits;}
  68   uint get_bits() const                 { return _bits;}
  69   void clear()                          { _bits = 0;}
  70   void set_all()                        { _bits = ~0u; }
  71   bool is_empty() const                 { return _bits == 0; }
  72   bool contains(uint var) const         { return (_bits & int_to_bit(var)) != 0; }
  73   bool is_singleton(uint var) const     { return (_bits == int_to_bit(var)); }
  74   bool contains_unknown() const         { return (_bits & UNKNOWN) != 0; }
  75   bool contains_allocated() const       { return (_bits & ALLOCATED) != 0; }
  76   bool contains_vars() const            { return (_bits & (((1 << MAXBIT) -1) << 2)) != 0; }
  77   void set(uint var)                    { _bits = int_to_bit(var); }
  78   void add(uint var)                    { _bits |= int_to_bit(var); }
  79   void add_unknown()                    { _bits = UNKNOWN; }
  80   void add_allocated()                  { _bits = ALLOCATED; }
  81   void set_union(const ArgumentMap &am)     { _bits |= am._bits; }
  82   void set_intersect(const ArgumentMap &am) { _bits |= am._bits; }
  83   void set_difference(const ArgumentMap &am) { _bits &=  ~am._bits; }
  84   void operator=(const ArgumentMap &am) { _bits = am._bits; }
  85   bool operator==(const ArgumentMap &am) { return _bits == am._bits; }
  86   bool operator!=(const ArgumentMap &am) { return _bits != am._bits; }
  87 };
  88 
  89 class BCEscapeAnalyzer::StateInfo {
  90 public:
  91   ArgumentMap *_vars;
  92   ArgumentMap *_stack;
  93   int _stack_height;
  94   int _max_stack;
  95   bool _initialized;
  96   ArgumentMap empty_map;
  97 
  98   StateInfo() {
  99     empty_map.clear();
 100   }
 101 
 102   ArgumentMap raw_pop()  { guarantee(_stack_height > 0, "stack underflow"); return _stack[--_stack_height]; }
 103   ArgumentMap  apop()    { return raw_pop(); }
 104   void spop()            { raw_pop(); }
 105   void lpop()            { spop(); spop(); }
 106   void raw_push(ArgumentMap i)   { guarantee(_stack_height < _max_stack, "stack overflow"); _stack[_stack_height++] = i; }
 107   void apush(ArgumentMap i)      { raw_push(i); }
 108   void spush()           { raw_push(empty_map); }
 109   void lpush()           { spush(); spush(); }
 110 
 111 };
 112 
 113 void BCEscapeAnalyzer::set_returned(ArgumentMap vars) {
 114   for (int i = 0; i < _arg_size; i++) {
 115     if (vars.contains(i))
 116       _arg_returned.set(i);
 117   }
 118   _return_local = _return_local && !(vars.contains_unknown() || vars.contains_allocated());
 119   _return_allocated = _return_allocated && vars.contains_allocated() && !(vars.contains_unknown() || vars.contains_vars());
 120 }
 121 
 122 // return true if any element of vars is an argument
 123 bool BCEscapeAnalyzer::is_argument(ArgumentMap vars) {
 124   for (int i = 0; i < _arg_size; i++) {
 125     if (vars.contains(i))
 126       return true;
 127   }
 128   return false;
 129 }
 130 
 131 // return true if any element of vars is an arg_stack argument
 132 bool BCEscapeAnalyzer::is_arg_stack(ArgumentMap vars){
 133   if (_conservative)
 134     return true;
 135   for (int i = 0; i < _arg_size; i++) {
 136     if (vars.contains(i) && _arg_stack.test(i))
 137       return true;
 138   }
 139   return false;
 140 }
 141 
 142 // return true if all argument elements of vars are returned
 143 bool BCEscapeAnalyzer::returns_all(ArgumentMap vars) {
 144   for (int i = 0; i < _arg_size; i++) {
 145     if (vars.contains(i) && !_arg_returned.test(i)) {
 146       return false;
 147     }
 148   }
 149   return true;
 150 }
 151 
 152 void BCEscapeAnalyzer::clear_bits(ArgumentMap vars, VectorSet &bm) {
 153   for (int i = 0; i < _arg_size; i++) {
 154     if (vars.contains(i)) {
 155       bm >>= i;
 156     }
 157   }
 158 }
 159 
 160 void BCEscapeAnalyzer::set_method_escape(ArgumentMap vars) {
 161   clear_bits(vars, _arg_local);
 162   if (vars.contains_allocated()) {
 163     _allocated_escapes = true;
 164   }
 165 }
 166 
 167 void BCEscapeAnalyzer::set_global_escape(ArgumentMap vars, bool merge) {
 168   clear_bits(vars, _arg_local);
 169   clear_bits(vars, _arg_stack);
 170   if (vars.contains_allocated())
 171     _allocated_escapes = true;
 172 
 173   if (merge && !vars.is_empty()) {
 174     // Merge new state into already processed block.
 175     // New state is not taken into account and
 176     // it may invalidate set_returned() result.
 177     if (vars.contains_unknown() || vars.contains_allocated()) {
 178       _return_local = false;
 179     }
 180     if (vars.contains_unknown() || vars.contains_vars()) {
 181       _return_allocated = false;
 182     }
 183     if (_return_local && vars.contains_vars() && !returns_all(vars)) {
 184       // Return result should be invalidated if args in new
 185       // state are not recorded in return state.
 186       _return_local = false;
 187     }
 188   }
 189 }
 190 
 191 void BCEscapeAnalyzer::set_dirty(ArgumentMap vars) {
 192   clear_bits(vars, _dirty);
 193 }
 194 
 195 void BCEscapeAnalyzer::set_modified(ArgumentMap vars, int offs, int size) {
 196 
 197   for (int i = 0; i < _arg_size; i++) {
 198     if (vars.contains(i)) {
 199       set_arg_modified(i, offs, size);
 200     }
 201   }
 202   if (vars.contains_unknown())
 203     _unknown_modified = true;
 204 }
 205 
 206 bool BCEscapeAnalyzer::is_recursive_call(ciMethod* callee) {
 207   for (BCEscapeAnalyzer* scope = this; scope != NULL; scope = scope->_parent) {
 208     if (scope->method() == callee) {
 209       return true;
 210     }
 211   }
 212   return false;
 213 }
 214 
 215 bool BCEscapeAnalyzer::is_arg_modified(int arg, int offset, int size_in_bytes) {
 216   if (offset == OFFSET_ANY)
 217     return _arg_modified[arg] != 0;
 218   assert(arg >= 0 && arg < _arg_size, "must be an argument.");
 219   bool modified = false;
 220   int l = offset / HeapWordSize;
 221   int h = round_to(offset + size_in_bytes, HeapWordSize) / HeapWordSize;
 222   if (l > ARG_OFFSET_MAX)
 223     l = ARG_OFFSET_MAX;
 224   if (h > ARG_OFFSET_MAX+1)
 225     h = ARG_OFFSET_MAX + 1;
 226   for (int i = l; i < h; i++) {
 227     modified = modified || (_arg_modified[arg] & (1 << i)) != 0;
 228   }
 229   return modified;
 230 }
 231 
 232 void BCEscapeAnalyzer::set_arg_modified(int arg, int offset, int size_in_bytes) {
 233   if (offset == OFFSET_ANY) {
 234     _arg_modified[arg] =  (uint) -1;
 235     return;
 236   }
 237   assert(arg >= 0 && arg < _arg_size, "must be an argument.");
 238   int l = offset / HeapWordSize;
 239   int h = round_to(offset + size_in_bytes, HeapWordSize) / HeapWordSize;
 240   if (l > ARG_OFFSET_MAX)
 241     l = ARG_OFFSET_MAX;
 242   if (h > ARG_OFFSET_MAX+1)
 243     h = ARG_OFFSET_MAX + 1;
 244   for (int i = l; i < h; i++) {
 245     _arg_modified[arg] |= (1 << i);
 246   }
 247 }
 248 
 249 void BCEscapeAnalyzer::invoke(StateInfo &state, Bytecodes::Code code, ciMethod* target, ciKlass* holder) {
 250   int i;
 251 
 252   // retrieve information about the callee
 253   ciInstanceKlass* klass = target->holder();
 254   ciInstanceKlass* calling_klass = method()->holder();
 255   ciInstanceKlass* callee_holder = ciEnv::get_instance_klass_for_declared_method_holder(holder);
 256   ciInstanceKlass* actual_recv = callee_holder;
 257 
 258   // Some methods are obviously bindable without any type checks so
 259   // convert them directly to an invokespecial or invokestatic.
 260   if (target->is_loaded() && !target->is_abstract() && target->can_be_statically_bound()) {
 261     switch (code) {
 262     case Bytecodes::_invokevirtual:
 263       code = Bytecodes::_invokespecial;
 264       break;
 265     case Bytecodes::_invokehandle:
 266       code = target->is_static() ? Bytecodes::_invokestatic : Bytecodes::_invokespecial;
 267       break;
 268     }
 269   }
 270 
 271   // compute size of arguments
 272   int arg_size = target->invoke_arg_size(code);
 273   int arg_base = MAX2(state._stack_height - arg_size, 0);
 274 
 275   // direct recursive calls are skipped if they can be bound statically without introducing
 276   // dependencies and if parameters are passed at the same position as in the current method
 277   // other calls are skipped if there are no unescaped arguments passed to them
 278   bool directly_recursive = (method() == target) &&
 279                (code != Bytecodes::_invokevirtual || target->is_final_method() || state._stack[arg_base] .is_empty());
 280 
 281   // check if analysis of callee can safely be skipped
 282   bool skip_callee = true;
 283   for (i = state._stack_height - 1; i >= arg_base && skip_callee; i--) {
 284     ArgumentMap arg = state._stack[i];
 285     skip_callee = !is_argument(arg) || !is_arg_stack(arg) || (directly_recursive && arg.is_singleton(i - arg_base));
 286   }
 287   // For now we conservatively skip invokedynamic.
 288   if (code == Bytecodes::_invokedynamic) {
 289     skip_callee = true;
 290   }
 291   if (skip_callee) {
 292     TRACE_BCEA(3, tty->print_cr("[EA] skipping method %s::%s", holder->name()->as_utf8(), target->name()->as_utf8()));
 293     for (i = 0; i < arg_size; i++) {
 294       set_method_escape(state.raw_pop());
 295     }
 296     _unknown_modified = true;  // assume the worst since we don't analyze the called method
 297     return;
 298   }
 299 
 300   // determine actual method (use CHA if necessary)
 301   ciMethod* inline_target = NULL;
 302   if (target->is_loaded() && klass->is_loaded()
 303       && (klass->is_initialized() || klass->is_interface() && target->holder()->is_initialized())
 304       && target->is_loaded()) {
 305     if (code == Bytecodes::_invokestatic
 306         || code == Bytecodes::_invokespecial
 307         || code == Bytecodes::_invokevirtual && target->is_final_method()) {
 308       inline_target = target;
 309     } else {
 310       inline_target = target->find_monomorphic_target(calling_klass, callee_holder, actual_recv);
 311     }
 312   }
 313 
 314   if (inline_target != NULL && !is_recursive_call(inline_target)) {
 315     // analyze callee
 316     BCEscapeAnalyzer analyzer(inline_target, this);
 317 
 318     // adjust escape state of actual parameters
 319     bool must_record_dependencies = false;
 320     for (i = arg_size - 1; i >= 0; i--) {
 321       ArgumentMap arg = state.raw_pop();
 322       // Check if callee arg is a caller arg or an allocated object
 323       bool allocated = arg.contains_allocated();
 324       if (!(is_argument(arg) || allocated))
 325         continue;
 326       for (int j = 0; j < _arg_size; j++) {
 327         if (arg.contains(j)) {
 328           _arg_modified[j] |= analyzer._arg_modified[i];
 329         }
 330       }
 331       if (!(is_arg_stack(arg) || allocated)) {
 332         // arguments have already been recognized as escaping
 333       } else if (analyzer.is_arg_stack(i) && !analyzer.is_arg_returned(i)) {
 334         set_method_escape(arg);
 335         must_record_dependencies = true;
 336       } else {
 337         set_global_escape(arg);
 338       }
 339     }
 340     _unknown_modified = _unknown_modified || analyzer.has_non_arg_side_affects();
 341 
 342     // record dependencies if at least one parameter retained stack-allocatable
 343     if (must_record_dependencies) {
 344       if (code == Bytecodes::_invokeinterface || code == Bytecodes::_invokevirtual && !target->is_final_method()) {
 345         _dependencies.append(actual_recv);
 346         _dependencies.append(inline_target);
 347       }
 348       _dependencies.appendAll(analyzer.dependencies());
 349     }
 350   } else {
 351     TRACE_BCEA(1, tty->print_cr("[EA] virtual method %s is not monomorphic.",
 352                                 target->name()->as_utf8()));
 353     // conservatively mark all actual parameters as escaping globally
 354     for (i = 0; i < arg_size; i++) {
 355       ArgumentMap arg = state.raw_pop();
 356       if (!is_argument(arg))
 357         continue;
 358       set_modified(arg, OFFSET_ANY, type2size[T_INT]*HeapWordSize);
 359       set_global_escape(arg);
 360     }
 361     _unknown_modified = true;  // assume the worst since we don't know the called method
 362   }
 363 }
 364 
 365 bool BCEscapeAnalyzer::contains(uint arg_set1, uint arg_set2) {
 366   return ((~arg_set1) | arg_set2) == 0;
 367 }
 368 
 369 
 370 void BCEscapeAnalyzer::iterate_one_block(ciBlock *blk, StateInfo &state, GrowableArray<ciBlock *> &successors) {
 371 
 372   blk->set_processed();
 373   ciBytecodeStream s(method());
 374   int limit_bci = blk->limit_bci();
 375   bool fall_through = false;
 376   ArgumentMap allocated_obj;
 377   allocated_obj.add_allocated();
 378   ArgumentMap unknown_obj;
 379   unknown_obj.add_unknown();
 380   ArgumentMap empty_map;
 381 
 382   s.reset_to_bci(blk->start_bci());
 383   while (s.next() != ciBytecodeStream::EOBC() && s.cur_bci() < limit_bci) {
 384     fall_through = true;
 385     switch (s.cur_bc()) {
 386       case Bytecodes::_nop:
 387         break;
 388       case Bytecodes::_aconst_null:
 389         state.apush(unknown_obj);
 390         break;
 391       case Bytecodes::_iconst_m1:
 392       case Bytecodes::_iconst_0:
 393       case Bytecodes::_iconst_1:
 394       case Bytecodes::_iconst_2:
 395       case Bytecodes::_iconst_3:
 396       case Bytecodes::_iconst_4:
 397       case Bytecodes::_iconst_5:
 398       case Bytecodes::_fconst_0:
 399       case Bytecodes::_fconst_1:
 400       case Bytecodes::_fconst_2:
 401       case Bytecodes::_bipush:
 402       case Bytecodes::_sipush:
 403         state.spush();
 404         break;
 405       case Bytecodes::_lconst_0:
 406       case Bytecodes::_lconst_1:
 407       case Bytecodes::_dconst_0:
 408       case Bytecodes::_dconst_1:
 409         state.lpush();
 410         break;
 411       case Bytecodes::_ldc:
 412       case Bytecodes::_ldc_w:
 413       case Bytecodes::_ldc2_w:
 414       {
 415         // Avoid calling get_constant() which will try to allocate
 416         // unloaded constant. We need only constant's type.
 417         int index = s.get_constant_pool_index();
 418         constantTag tag = s.get_constant_pool_tag(index);
 419         if (tag.is_long() || tag.is_double()) {
 420           // Only longs and doubles use 2 stack slots.
 421           state.lpush();
 422         } else if (tag.basic_type() == T_OBJECT) {
 423           state.apush(unknown_obj);
 424         } else {
 425           state.spush();
 426         }
 427         break;
 428       }
 429       case Bytecodes::_aload:
 430       case Bytecodes::_vload:
 431         state.apush(state._vars[s.get_index()]);
 432         break;
 433       case Bytecodes::_iload:
 434       case Bytecodes::_fload:
 435       case Bytecodes::_iload_0:
 436       case Bytecodes::_iload_1:
 437       case Bytecodes::_iload_2:
 438       case Bytecodes::_iload_3:
 439       case Bytecodes::_fload_0:
 440       case Bytecodes::_fload_1:
 441       case Bytecodes::_fload_2:
 442       case Bytecodes::_fload_3:
 443         state.spush();
 444         break;
 445       case Bytecodes::_lload:
 446       case Bytecodes::_dload:
 447       case Bytecodes::_lload_0:
 448       case Bytecodes::_lload_1:
 449       case Bytecodes::_lload_2:
 450       case Bytecodes::_lload_3:
 451       case Bytecodes::_dload_0:
 452       case Bytecodes::_dload_1:
 453       case Bytecodes::_dload_2:
 454       case Bytecodes::_dload_3:
 455         state.lpush();
 456         break;
 457       case Bytecodes::_aload_0:
 458         state.apush(state._vars[0]);
 459         break;
 460       case Bytecodes::_aload_1:
 461         state.apush(state._vars[1]);
 462         break;
 463       case Bytecodes::_aload_2:
 464         state.apush(state._vars[2]);
 465         break;
 466       case Bytecodes::_aload_3:
 467         state.apush(state._vars[3]);
 468         break;
 469       case Bytecodes::_iaload:
 470       case Bytecodes::_faload:
 471       case Bytecodes::_baload:
 472       case Bytecodes::_caload:
 473       case Bytecodes::_saload:
 474         state.spop();
 475         set_method_escape(state.apop());
 476         state.spush();
 477         break;
 478       case Bytecodes::_laload:
 479       case Bytecodes::_daload:
 480         state.spop();
 481         set_method_escape(state.apop());
 482         state.lpush();
 483         break;
 484       case Bytecodes::_vaload:
 485       case Bytecodes::_aaload:
 486         { state.spop();
 487           ArgumentMap array = state.apop();
 488           set_method_escape(array);
 489           state.apush(unknown_obj);
 490           set_dirty(array);
 491         }
 492         break;
 493       case Bytecodes::_istore:
 494       case Bytecodes::_fstore:
 495       case Bytecodes::_istore_0:
 496       case Bytecodes::_istore_1:
 497       case Bytecodes::_istore_2:
 498       case Bytecodes::_istore_3:
 499       case Bytecodes::_fstore_0:
 500       case Bytecodes::_fstore_1:
 501       case Bytecodes::_fstore_2:
 502       case Bytecodes::_fstore_3:
 503         state.spop();
 504         break;
 505       case Bytecodes::_lstore:
 506       case Bytecodes::_dstore:
 507       case Bytecodes::_lstore_0:
 508       case Bytecodes::_lstore_1:
 509       case Bytecodes::_lstore_2:
 510       case Bytecodes::_lstore_3:
 511       case Bytecodes::_dstore_0:
 512       case Bytecodes::_dstore_1:
 513       case Bytecodes::_dstore_2:
 514       case Bytecodes::_dstore_3:
 515         state.lpop();
 516         break;
 517       case Bytecodes::_astore:
 518       case Bytecodes::_vstore:
 519         state._vars[s.get_index()] = state.apop();
 520         break;
 521       case Bytecodes::_astore_0:
 522         state._vars[0] = state.apop();
 523         break;
 524       case Bytecodes::_astore_1:
 525         state._vars[1] = state.apop();
 526         break;
 527       case Bytecodes::_astore_2:
 528         state._vars[2] = state.apop();
 529         break;
 530       case Bytecodes::_astore_3:
 531         state._vars[3] = state.apop();
 532         break;
 533       case Bytecodes::_iastore:
 534       case Bytecodes::_fastore:
 535       case Bytecodes::_bastore:
 536       case Bytecodes::_castore:
 537       case Bytecodes::_sastore:
 538       {
 539         state.spop();
 540         state.spop();
 541         ArgumentMap arr = state.apop();
 542         set_method_escape(arr);
 543         set_modified(arr, OFFSET_ANY, type2size[T_INT]*HeapWordSize);
 544         break;
 545       }
 546       case Bytecodes::_lastore:
 547       case Bytecodes::_dastore:
 548       {
 549         state.lpop();
 550         state.spop();
 551         ArgumentMap arr = state.apop();
 552         set_method_escape(arr);
 553         set_modified(arr, OFFSET_ANY, type2size[T_LONG]*HeapWordSize);
 554         break;
 555       }

 556       case Bytecodes::_aastore:
 557       {
 558         set_global_escape(state.apop());
 559         state.spop();
 560         ArgumentMap arr = state.apop();
 561         set_modified(arr, OFFSET_ANY, type2size[T_OBJECT]*HeapWordSize);
 562         break;
 563       }
 564       case Bytecodes::_vastore:
 565       {
 566         set_global_escape(state.apop());
 567         state.spop();
 568         ArgumentMap arr = state.apop();
 569         // If the array is flattened, a larger part of it is modified than
 570         // the size of a reference. However, if OFFSET_ANY is given as
 571         // parameter to set_modified(), size is not taken into account.
 572         set_modified(arr, OFFSET_ANY, type2size[T_VALUETYPE]*HeapWordSize);
 573         break;
 574       }
 575       case Bytecodes::_pop:
 576         state.raw_pop();
 577         break;
 578       case Bytecodes::_pop2:
 579         state.raw_pop();
 580         state.raw_pop();
 581         break;
 582       case Bytecodes::_dup:
 583         { ArgumentMap w1 = state.raw_pop();
 584           state.raw_push(w1);
 585           state.raw_push(w1);
 586         }
 587         break;
 588       case Bytecodes::_dup_x1:
 589         { ArgumentMap w1 = state.raw_pop();
 590           ArgumentMap w2 = state.raw_pop();
 591           state.raw_push(w1);
 592           state.raw_push(w2);
 593           state.raw_push(w1);
 594         }
 595         break;
 596       case Bytecodes::_dup_x2:
 597         { ArgumentMap w1 = state.raw_pop();
 598           ArgumentMap w2 = state.raw_pop();
 599           ArgumentMap w3 = state.raw_pop();
 600           state.raw_push(w1);
 601           state.raw_push(w3);
 602           state.raw_push(w2);
 603           state.raw_push(w1);
 604         }
 605         break;
 606       case Bytecodes::_dup2:
 607         { ArgumentMap w1 = state.raw_pop();
 608           ArgumentMap w2 = state.raw_pop();
 609           state.raw_push(w2);
 610           state.raw_push(w1);
 611           state.raw_push(w2);
 612           state.raw_push(w1);
 613         }
 614         break;
 615       case Bytecodes::_dup2_x1:
 616         { ArgumentMap w1 = state.raw_pop();
 617           ArgumentMap w2 = state.raw_pop();
 618           ArgumentMap w3 = state.raw_pop();
 619           state.raw_push(w2);
 620           state.raw_push(w1);
 621           state.raw_push(w3);
 622           state.raw_push(w2);
 623           state.raw_push(w1);
 624         }
 625         break;
 626       case Bytecodes::_dup2_x2:
 627         { ArgumentMap w1 = state.raw_pop();
 628           ArgumentMap w2 = state.raw_pop();
 629           ArgumentMap w3 = state.raw_pop();
 630           ArgumentMap w4 = state.raw_pop();
 631           state.raw_push(w2);
 632           state.raw_push(w1);
 633           state.raw_push(w4);
 634           state.raw_push(w3);
 635           state.raw_push(w2);
 636           state.raw_push(w1);
 637         }
 638         break;
 639       case Bytecodes::_swap:
 640         { ArgumentMap w1 = state.raw_pop();
 641           ArgumentMap w2 = state.raw_pop();
 642           state.raw_push(w1);
 643           state.raw_push(w2);
 644         }
 645         break;
 646       case Bytecodes::_iadd:
 647       case Bytecodes::_fadd:
 648       case Bytecodes::_isub:
 649       case Bytecodes::_fsub:
 650       case Bytecodes::_imul:
 651       case Bytecodes::_fmul:
 652       case Bytecodes::_idiv:
 653       case Bytecodes::_fdiv:
 654       case Bytecodes::_irem:
 655       case Bytecodes::_frem:
 656       case Bytecodes::_iand:
 657       case Bytecodes::_ior:
 658       case Bytecodes::_ixor:
 659         state.spop();
 660         state.spop();
 661         state.spush();
 662         break;
 663       case Bytecodes::_ladd:
 664       case Bytecodes::_dadd:
 665       case Bytecodes::_lsub:
 666       case Bytecodes::_dsub:
 667       case Bytecodes::_lmul:
 668       case Bytecodes::_dmul:
 669       case Bytecodes::_ldiv:
 670       case Bytecodes::_ddiv:
 671       case Bytecodes::_lrem:
 672       case Bytecodes::_drem:
 673       case Bytecodes::_land:
 674       case Bytecodes::_lor:
 675       case Bytecodes::_lxor:
 676         state.lpop();
 677         state.lpop();
 678         state.lpush();
 679         break;
 680       case Bytecodes::_ishl:
 681       case Bytecodes::_ishr:
 682       case Bytecodes::_iushr:
 683         state.spop();
 684         state.spop();
 685         state.spush();
 686         break;
 687       case Bytecodes::_lshl:
 688       case Bytecodes::_lshr:
 689       case Bytecodes::_lushr:
 690         state.spop();
 691         state.lpop();
 692         state.lpush();
 693         break;
 694       case Bytecodes::_ineg:
 695       case Bytecodes::_fneg:
 696         state.spop();
 697         state.spush();
 698         break;
 699       case Bytecodes::_lneg:
 700       case Bytecodes::_dneg:
 701         state.lpop();
 702         state.lpush();
 703         break;
 704       case Bytecodes::_iinc:
 705         break;
 706       case Bytecodes::_i2l:
 707       case Bytecodes::_i2d:
 708       case Bytecodes::_f2l:
 709       case Bytecodes::_f2d:
 710         state.spop();
 711         state.lpush();
 712         break;
 713       case Bytecodes::_i2f:
 714       case Bytecodes::_f2i:
 715         state.spop();
 716         state.spush();
 717         break;
 718       case Bytecodes::_l2i:
 719       case Bytecodes::_l2f:
 720       case Bytecodes::_d2i:
 721       case Bytecodes::_d2f:
 722         state.lpop();
 723         state.spush();
 724         break;
 725       case Bytecodes::_l2d:
 726       case Bytecodes::_d2l:
 727         state.lpop();
 728         state.lpush();
 729         break;
 730       case Bytecodes::_i2b:
 731       case Bytecodes::_i2c:
 732       case Bytecodes::_i2s:
 733         state.spop();
 734         state.spush();
 735         break;
 736       case Bytecodes::_lcmp:
 737       case Bytecodes::_dcmpl:
 738       case Bytecodes::_dcmpg:
 739         state.lpop();
 740         state.lpop();
 741         state.spush();
 742         break;
 743       case Bytecodes::_fcmpl:
 744       case Bytecodes::_fcmpg:
 745         state.spop();
 746         state.spop();
 747         state.spush();
 748         break;
 749       case Bytecodes::_ifeq:
 750       case Bytecodes::_ifne:
 751       case Bytecodes::_iflt:
 752       case Bytecodes::_ifge:
 753       case Bytecodes::_ifgt:
 754       case Bytecodes::_ifle:
 755       {
 756         state.spop();
 757         int dest_bci = s.get_dest();
 758         assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
 759         assert(s.next_bci() == limit_bci, "branch must end block");
 760         successors.push(_methodBlocks->block_containing(dest_bci));
 761         break;
 762       }
 763       case Bytecodes::_if_icmpeq:
 764       case Bytecodes::_if_icmpne:
 765       case Bytecodes::_if_icmplt:
 766       case Bytecodes::_if_icmpge:
 767       case Bytecodes::_if_icmpgt:
 768       case Bytecodes::_if_icmple:
 769       {
 770         state.spop();
 771         state.spop();
 772         int dest_bci = s.get_dest();
 773         assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
 774         assert(s.next_bci() == limit_bci, "branch must end block");
 775         successors.push(_methodBlocks->block_containing(dest_bci));
 776         break;
 777       }
 778       case Bytecodes::_if_acmpeq:
 779       case Bytecodes::_if_acmpne:
 780       {
 781         set_method_escape(state.apop());
 782         set_method_escape(state.apop());
 783         int dest_bci = s.get_dest();
 784         assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
 785         assert(s.next_bci() == limit_bci, "branch must end block");
 786         successors.push(_methodBlocks->block_containing(dest_bci));
 787         break;
 788       }
 789       case Bytecodes::_goto:
 790       {
 791         int dest_bci = s.get_dest();
 792         assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
 793         assert(s.next_bci() == limit_bci, "branch must end block");
 794         successors.push(_methodBlocks->block_containing(dest_bci));
 795         fall_through = false;
 796         break;
 797       }
 798       case Bytecodes::_jsr:
 799       {
 800         int dest_bci = s.get_dest();
 801         assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
 802         assert(s.next_bci() == limit_bci, "branch must end block");
 803         state.apush(empty_map);
 804         successors.push(_methodBlocks->block_containing(dest_bci));
 805         fall_through = false;
 806         break;
 807       }
 808       case Bytecodes::_ret:
 809         // we don't track  the destination of a "ret" instruction
 810         assert(s.next_bci() == limit_bci, "branch must end block");
 811         fall_through = false;
 812         break;
 813       case Bytecodes::_return:
 814         assert(s.next_bci() == limit_bci, "return must end block");
 815         fall_through = false;
 816         break;
 817       case Bytecodes::_tableswitch:
 818         {
 819           state.spop();
 820           Bytecode_tableswitch sw(&s);
 821           int len = sw.length();
 822           int dest_bci;
 823           for (int i = 0; i < len; i++) {
 824             dest_bci = s.cur_bci() + sw.dest_offset_at(i);
 825             assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
 826             successors.push(_methodBlocks->block_containing(dest_bci));
 827           }
 828           dest_bci = s.cur_bci() + sw.default_offset();
 829           assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
 830           successors.push(_methodBlocks->block_containing(dest_bci));
 831           assert(s.next_bci() == limit_bci, "branch must end block");
 832           fall_through = false;
 833           break;
 834         }
 835       case Bytecodes::_lookupswitch:
 836         {
 837           state.spop();
 838           Bytecode_lookupswitch sw(&s);
 839           int len = sw.number_of_pairs();
 840           int dest_bci;
 841           for (int i = 0; i < len; i++) {
 842             dest_bci = s.cur_bci() + sw.pair_at(i).offset();
 843             assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
 844             successors.push(_methodBlocks->block_containing(dest_bci));
 845           }
 846           dest_bci = s.cur_bci() + sw.default_offset();
 847           assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
 848           successors.push(_methodBlocks->block_containing(dest_bci));
 849           fall_through = false;
 850           break;
 851         }
 852       case Bytecodes::_ireturn:
 853       case Bytecodes::_freturn:
 854         state.spop();
 855         fall_through = false;
 856         break;
 857       case Bytecodes::_lreturn:
 858       case Bytecodes::_dreturn:
 859         state.lpop();
 860         fall_through = false;
 861         break;
 862       case Bytecodes::_areturn:
 863       case Bytecodes::_vreturn:
 864         set_returned(state.apop());
 865         fall_through = false;
 866         break;
 867       case Bytecodes::_getstatic:
 868       case Bytecodes::_getfield:
 869       case Bytecodes::_vgetfield:
 870         { bool ignored_will_link;
 871           ciField* field = s.get_field(ignored_will_link);
 872           BasicType field_type = field->type()->basic_type();
 873           if (s.cur_bc() != Bytecodes::_getstatic) {
 874             set_method_escape(state.apop());
 875           }
 876           if (field_type == T_OBJECT || field_type == T_ARRAY) {
 877             state.apush(unknown_obj);
 878           } else if (type2size[field_type] == 1) {
 879             state.spush();
 880           } else {
 881             state.lpush();
 882           }
 883         }
 884         break;
 885       case Bytecodes::_putstatic:
 886       case Bytecodes::_putfield:
 887         { bool will_link;
 888           ciField* field = s.get_field(will_link);
 889           BasicType field_type = field->type()->basic_type();
 890           if (field_type == T_OBJECT || field_type == T_ARRAY) {
 891             set_global_escape(state.apop());
 892           } else if (type2size[field_type] == 1) {
 893             state.spop();
 894           } else {
 895             state.lpop();
 896           }
 897           if (s.cur_bc() != Bytecodes::_putstatic) {
 898             ArgumentMap p = state.apop();
 899             set_method_escape(p);
 900             set_modified(p, will_link ? field->offset() : OFFSET_ANY, type2size[field_type]*HeapWordSize);
 901           }
 902         }
 903         break;
 904       case Bytecodes::_invokevirtual:
 905       case Bytecodes::_invokespecial:
 906       case Bytecodes::_invokestatic:
 907       case Bytecodes::_invokedynamic:
 908       case Bytecodes::_invokeinterface:
 909         { bool ignored_will_link;
 910           ciSignature* declared_signature = NULL;
 911           ciMethod* target = s.get_method(ignored_will_link, &declared_signature);
 912           ciKlass*  holder = s.get_declared_method_holder();
 913           assert(declared_signature != NULL, "cannot be null");
 914           // If the current bytecode has an attached appendix argument,
 915           // push an unknown object to represent that argument. (Analysis
 916           // of dynamic call sites, especially invokehandle calls, needs
 917           // the appendix argument on the stack, in addition to "regular" arguments
 918           // pushed onto the stack by bytecode instructions preceding the call.)
 919           //
 920           // The escape analyzer does _not_ use the ciBytecodeStream::has_appendix(s)
 921           // method to determine whether the current bytecode has an appendix argument.
 922           // The has_appendix() method obtains the appendix from the
 923           // ConstantPoolCacheEntry::_f1 field, which can happen concurrently with
 924           // resolution of dynamic call sites. Callees in the
 925           // ciBytecodeStream::get_method() call above also access the _f1 field;
 926           // interleaving the get_method() and has_appendix() calls in the current
 927           // method with call site resolution can lead to an inconsistent view of
 928           // the current method's argument count. In particular, some interleaving(s)
 929           // can cause the method's argument count to not include the appendix, which
 930           // then leads to stack over-/underflow in the escape analyzer.
 931           //
 932           // Instead of pushing the argument if has_appendix() is true, the escape analyzer
 933           // pushes an appendix for all call sites targeted by invokedynamic and invokehandle
 934           // instructions, except if the call site is the _invokeBasic intrinsic
 935           // (that intrinsic is always targeted by an invokehandle instruction but does
 936           // not have an appendix argument).
 937           if (target->is_loaded() &&
 938               Bytecodes::has_optional_appendix(s.cur_bc_raw()) &&
 939               target->intrinsic_id() != vmIntrinsics::_invokeBasic) {
 940             state.apush(unknown_obj);
 941           }
 942           // Pass in raw bytecode because we need to see invokehandle instructions.
 943           invoke(state, s.cur_bc_raw(), target, holder);
 944           // We are using the return type of the declared signature here because
 945           // it might be a more concrete type than the one from the target (for
 946           // e.g. invokedynamic and invokehandle).
 947           ciType* return_type = declared_signature->return_type();
 948           if (!return_type->is_primitive_type()) {
 949             state.apush(unknown_obj);
 950           } else if (return_type->is_one_word()) {
 951             state.spush();
 952           } else if (return_type->is_two_word()) {
 953             state.lpush();
 954           }
 955         }
 956         break;
 957       case Bytecodes::_new:
 958       case Bytecodes::_vdefault:
 959         state.apush(allocated_obj);
 960         break;
 961       case Bytecodes::_vwithfield: {
 962         bool will_link;
 963         ciField* field = s.get_field(will_link);
 964         BasicType field_type = field->type()->basic_type();
 965         if (field_type == T_OBJECT || field_type == T_ARRAY) {
 966           set_global_escape(state.apop());
 967         } else if (type2size[field_type] == 1) {
 968           state.spop();
 969         } else {
 970           state.lpop();
 971         }
 972         state.apop();
 973         state.apush(allocated_obj);
 974         break;
 975       }
 976       case Bytecodes::_newarray:
 977       case Bytecodes::_anewarray:
 978         state.spop();
 979         state.apush(allocated_obj);
 980         break;
 981       case Bytecodes::_multianewarray:
 982         { int i = s.cur_bcp()[3];
 983           while (i-- > 0) state.spop();
 984           state.apush(allocated_obj);
 985         }
 986         break;
 987       case Bytecodes::_arraylength:
 988         set_method_escape(state.apop());
 989         state.spush();
 990         break;
 991       case Bytecodes::_athrow:
 992         set_global_escape(state.apop());
 993         fall_through = false;
 994         break;
 995       case Bytecodes::_checkcast:
 996         { ArgumentMap obj = state.apop();
 997           set_method_escape(obj);
 998           state.apush(obj);
 999         }
1000         break;
1001       case Bytecodes::_instanceof:
1002         set_method_escape(state.apop());
1003         state.spush();
1004         break;
1005       case Bytecodes::_monitorenter:
1006       case Bytecodes::_monitorexit:
1007         state.apop();
1008         break;
1009       case Bytecodes::_wide:
1010         ShouldNotReachHere();
1011         break;
1012       case Bytecodes::_ifnull:
1013       case Bytecodes::_ifnonnull:
1014       {
1015         set_method_escape(state.apop());
1016         int dest_bci = s.get_dest();
1017         assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
1018         assert(s.next_bci() == limit_bci, "branch must end block");
1019         successors.push(_methodBlocks->block_containing(dest_bci));
1020         break;
1021       }
1022       case Bytecodes::_goto_w:
1023       {
1024         int dest_bci = s.get_far_dest();
1025         assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
1026         assert(s.next_bci() == limit_bci, "branch must end block");
1027         successors.push(_methodBlocks->block_containing(dest_bci));
1028         fall_through = false;
1029         break;
1030       }
1031       case Bytecodes::_jsr_w:
1032       {
1033         int dest_bci = s.get_far_dest();
1034         assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
1035         assert(s.next_bci() == limit_bci, "branch must end block");
1036         state.apush(empty_map);
1037         successors.push(_methodBlocks->block_containing(dest_bci));
1038         fall_through = false;
1039         break;
1040       }
1041       case Bytecodes::_breakpoint:
1042         break;
1043       default:
1044         ShouldNotReachHere();
1045         break;
1046     }
1047 
1048   }
1049   if (fall_through) {
1050     int fall_through_bci = s.cur_bci();
1051     if (fall_through_bci < _method->code_size()) {
1052       assert(_methodBlocks->is_block_start(fall_through_bci), "must fall through to block start.");
1053       successors.push(_methodBlocks->block_containing(fall_through_bci));
1054     }
1055   }
1056 }
1057 
1058 void BCEscapeAnalyzer::merge_block_states(StateInfo *blockstates, ciBlock *dest, StateInfo *s_state) {
1059   StateInfo *d_state = blockstates + dest->index();
1060   int nlocals = _method->max_locals();
1061 
1062   // exceptions may cause transfer of control to handlers in the middle of a
1063   // block, so we don't merge the incoming state of exception handlers
1064   if (dest->is_handler())
1065     return;
1066   if (!d_state->_initialized ) {
1067     // destination not initialized, just copy
1068     for (int i = 0; i < nlocals; i++) {
1069       d_state->_vars[i] = s_state->_vars[i];
1070     }
1071     for (int i = 0; i < s_state->_stack_height; i++) {
1072       d_state->_stack[i] = s_state->_stack[i];
1073     }
1074     d_state->_stack_height = s_state->_stack_height;
1075     d_state->_max_stack = s_state->_max_stack;
1076     d_state->_initialized = true;
1077   } else if (!dest->processed()) {
1078     // we have not yet walked the bytecodes of dest, we can merge
1079     // the states
1080     assert(d_state->_stack_height == s_state->_stack_height, "computed stack heights must match");
1081     for (int i = 0; i < nlocals; i++) {
1082       d_state->_vars[i].set_union(s_state->_vars[i]);
1083     }
1084     for (int i = 0; i < s_state->_stack_height; i++) {
1085       d_state->_stack[i].set_union(s_state->_stack[i]);
1086     }
1087   } else {
1088     // the bytecodes of dest have already been processed, mark any
1089     // arguments in the source state which are not in the dest state
1090     // as global escape.
1091     // Future refinement:  we only need to mark these variable to the
1092     // maximum escape of any variables in dest state
1093     assert(d_state->_stack_height == s_state->_stack_height, "computed stack heights must match");
1094     ArgumentMap extra_vars;
1095     for (int i = 0; i < nlocals; i++) {
1096       ArgumentMap t;
1097       t = s_state->_vars[i];
1098       t.set_difference(d_state->_vars[i]);
1099       extra_vars.set_union(t);
1100     }
1101     for (int i = 0; i < s_state->_stack_height; i++) {
1102       ArgumentMap t;
1103       //extra_vars |= !d_state->_vars[i] & s_state->_vars[i];
1104       t.clear();
1105       t = s_state->_stack[i];
1106       t.set_difference(d_state->_stack[i]);
1107       extra_vars.set_union(t);
1108     }
1109     set_global_escape(extra_vars, true);
1110   }
1111 }
1112 
1113 void BCEscapeAnalyzer::iterate_blocks(Arena *arena) {
1114   int numblocks = _methodBlocks->num_blocks();
1115   int stkSize   = _method->max_stack();
1116   int numLocals = _method->max_locals();
1117   StateInfo state;
1118 
1119   int datacount = (numblocks + 1) * (stkSize + numLocals);
1120   int datasize = datacount * sizeof(ArgumentMap);
1121   StateInfo *blockstates = (StateInfo *) arena->Amalloc(numblocks * sizeof(StateInfo));
1122   ArgumentMap *statedata  = (ArgumentMap *) arena->Amalloc(datasize);
1123   for (int i = 0; i < datacount; i++) ::new ((void*)&statedata[i]) ArgumentMap();
1124   ArgumentMap *dp = statedata;
1125   state._vars = dp;
1126   dp += numLocals;
1127   state._stack = dp;
1128   dp += stkSize;
1129   state._initialized = false;
1130   state._max_stack = stkSize;
1131   for (int i = 0; i < numblocks; i++) {
1132     blockstates[i]._vars = dp;
1133     dp += numLocals;
1134     blockstates[i]._stack = dp;
1135     dp += stkSize;
1136     blockstates[i]._initialized = false;
1137     blockstates[i]._stack_height = 0;
1138     blockstates[i]._max_stack  = stkSize;
1139   }
1140   GrowableArray<ciBlock *> worklist(arena, numblocks / 4, 0, NULL);
1141   GrowableArray<ciBlock *> successors(arena, 4, 0, NULL);
1142 
1143   _methodBlocks->clear_processed();
1144 
1145   // initialize block 0 state from method signature
1146   ArgumentMap allVars;   // all oop arguments to method
1147   ciSignature* sig = method()->signature();
1148   int j = 0;
1149   ciBlock* first_blk = _methodBlocks->block_containing(0);
1150   int fb_i = first_blk->index();
1151   if (!method()->is_static()) {
1152     // record information for "this"
1153     blockstates[fb_i]._vars[j].set(j);
1154     allVars.add(j);
1155     j++;
1156   }
1157   for (int i = 0; i < sig->count(); i++) {
1158     ciType* t = sig->type_at(i);
1159     if (!t->is_primitive_type()) {
1160       blockstates[fb_i]._vars[j].set(j);
1161       allVars.add(j);
1162     }
1163     j += t->size();
1164   }
1165   blockstates[fb_i]._initialized = true;
1166   assert(j == _arg_size, "just checking");
1167 
1168   ArgumentMap unknown_map;
1169   unknown_map.add_unknown();
1170 
1171   worklist.push(first_blk);
1172   while(worklist.length() > 0) {
1173     ciBlock *blk = worklist.pop();
1174     StateInfo *blkState = blockstates + blk->index();
1175     if (blk->is_handler() || blk->is_ret_target()) {
1176       // for an exception handler or a target of a ret instruction, we assume the worst case,
1177       // that any variable could contain any argument
1178       for (int i = 0; i < numLocals; i++) {
1179         state._vars[i] = allVars;
1180       }
1181       if (blk->is_handler()) {
1182         state._stack_height = 1;
1183       } else {
1184         state._stack_height = blkState->_stack_height;
1185       }
1186       for (int i = 0; i < state._stack_height; i++) {
1187 // ??? should this be unknown_map ???
1188         state._stack[i] = allVars;
1189       }
1190     } else {
1191       for (int i = 0; i < numLocals; i++) {
1192         state._vars[i] = blkState->_vars[i];
1193       }
1194       for (int i = 0; i < blkState->_stack_height; i++) {
1195         state._stack[i] = blkState->_stack[i];
1196       }
1197       state._stack_height = blkState->_stack_height;
1198     }
1199     iterate_one_block(blk, state, successors);
1200     // if this block has any exception handlers, push them
1201     // onto successor list
1202     if (blk->has_handler()) {
1203       DEBUG_ONLY(int handler_count = 0;)
1204       int blk_start = blk->start_bci();
1205       int blk_end = blk->limit_bci();
1206       for (int i = 0; i < numblocks; i++) {
1207         ciBlock *b = _methodBlocks->block(i);
1208         if (b->is_handler()) {
1209           int ex_start = b->ex_start_bci();
1210           int ex_end = b->ex_limit_bci();
1211           if ((ex_start >= blk_start && ex_start < blk_end) ||
1212               (ex_end > blk_start && ex_end <= blk_end)) {
1213             successors.push(b);
1214           }
1215           DEBUG_ONLY(handler_count++;)
1216         }
1217       }
1218       assert(handler_count > 0, "must find at least one handler");
1219     }
1220     // merge computed variable state with successors
1221     while(successors.length() > 0) {
1222       ciBlock *succ = successors.pop();
1223       merge_block_states(blockstates, succ, &state);
1224       if (!succ->processed())
1225         worklist.push(succ);
1226     }
1227   }
1228 }
1229 
1230 bool BCEscapeAnalyzer::do_analysis() {
1231   Arena* arena = CURRENT_ENV->arena();
1232   // identify basic blocks
1233   _methodBlocks = _method->get_method_blocks();
1234 
1235   iterate_blocks(arena);
1236   // TEMPORARY
1237   return true;
1238 }
1239 
1240 vmIntrinsics::ID BCEscapeAnalyzer::known_intrinsic() {
1241   vmIntrinsics::ID iid = method()->intrinsic_id();
1242 
1243   if (iid == vmIntrinsics::_getClass ||
1244       iid == vmIntrinsics::_hashCode)
1245     return iid;
1246   else
1247     return vmIntrinsics::_none;
1248 }
1249 
1250 bool BCEscapeAnalyzer::compute_escape_for_intrinsic(vmIntrinsics::ID iid) {
1251   ArgumentMap arg;
1252   arg.clear();
1253   switch (iid) {
1254   case vmIntrinsics::_getClass:
1255     _return_local = false;
1256     break;
1257   case vmIntrinsics::_hashCode:
1258     // initialized state is correct
1259     break;
1260   default:
1261     assert(false, "unexpected intrinsic");
1262   }
1263   return true;
1264 }
1265 
1266 void BCEscapeAnalyzer::initialize() {
1267   int i;
1268 
1269   // clear escape information (method may have been deoptimized)
1270   methodData()->clear_escape_info();
1271 
1272   // initialize escape state of object parameters
1273   ciSignature* sig = method()->signature();
1274   int j = 0;
1275   if (!method()->is_static()) {
1276     _arg_local.set(0);
1277     _arg_stack.set(0);
1278     j++;
1279   }
1280   for (i = 0; i < sig->count(); i++) {
1281     ciType* t = sig->type_at(i);
1282     if (!t->is_primitive_type()) {
1283       _arg_local.set(j);
1284       _arg_stack.set(j);
1285     }
1286     j += t->size();
1287   }
1288   assert(j == _arg_size, "just checking");
1289 
1290   // start with optimistic assumption
1291   ciType *rt = _method->return_type();
1292   if (rt->is_primitive_type()) {
1293     _return_local = false;
1294     _return_allocated = false;
1295   } else {
1296     _return_local = true;
1297     _return_allocated = true;
1298   }
1299   _allocated_escapes = false;
1300   _unknown_modified = false;
1301 }
1302 
1303 void BCEscapeAnalyzer::clear_escape_info() {
1304   ciSignature* sig = method()->signature();
1305   int arg_count = sig->count();
1306   ArgumentMap var;
1307   if (!method()->is_static()) {
1308     arg_count++;  // allow for "this"
1309   }
1310   for (int i = 0; i < arg_count; i++) {
1311     set_arg_modified(i, OFFSET_ANY, 4);
1312     var.clear();
1313     var.set(i);
1314     set_modified(var, OFFSET_ANY, 4);
1315     set_global_escape(var);
1316   }
1317   _arg_local.Clear();
1318   _arg_stack.Clear();
1319   _arg_returned.Clear();
1320   _return_local = false;
1321   _return_allocated = false;
1322   _allocated_escapes = true;
1323   _unknown_modified = true;
1324 }
1325 
1326 
1327 void BCEscapeAnalyzer::compute_escape_info() {
1328   int i;
1329   assert(!methodData()->has_escape_info(), "do not overwrite escape info");
1330 
1331   vmIntrinsics::ID iid = known_intrinsic();
1332 
1333   // check if method can be analyzed
1334   if (iid ==  vmIntrinsics::_none && (method()->is_abstract() || method()->is_native() || !method()->holder()->is_initialized()
1335       || _level > MaxBCEAEstimateLevel
1336       || method()->code_size() > MaxBCEAEstimateSize)) {
1337     if (BCEATraceLevel >= 1) {
1338       tty->print("Skipping method because: ");
1339       if (method()->is_abstract())
1340         tty->print_cr("method is abstract.");
1341       else if (method()->is_native())
1342         tty->print_cr("method is native.");
1343       else if (!method()->holder()->is_initialized())
1344         tty->print_cr("class of method is not initialized.");
1345       else if (_level > MaxBCEAEstimateLevel)
1346         tty->print_cr("level (%d) exceeds MaxBCEAEstimateLevel (%d).",
1347                       _level, (int) MaxBCEAEstimateLevel);
1348       else if (method()->code_size() > MaxBCEAEstimateSize)
1349         tty->print_cr("code size (%d) exceeds MaxBCEAEstimateSize (%d).",
1350                       method()->code_size(), (int) MaxBCEAEstimateSize);
1351       else
1352         ShouldNotReachHere();
1353     }
1354     clear_escape_info();
1355 
1356     return;
1357   }
1358 
1359   if (BCEATraceLevel >= 1) {
1360     tty->print("[EA] estimating escape information for");
1361     if (iid != vmIntrinsics::_none)
1362       tty->print(" intrinsic");
1363     method()->print_short_name();
1364     tty->print_cr(" (%d bytes)", method()->code_size());
1365   }
1366 
1367   bool success;
1368 
1369   initialize();
1370 
1371   // Do not scan method if it has no object parameters and
1372   // does not returns an object (_return_allocated is set in initialize()).
1373   if (_arg_local.Size() == 0 && !_return_allocated) {
1374     // Clear all info since method's bytecode was not analysed and
1375     // set pessimistic escape information.
1376     clear_escape_info();
1377     methodData()->set_eflag(MethodData::allocated_escapes);
1378     methodData()->set_eflag(MethodData::unknown_modified);
1379     methodData()->set_eflag(MethodData::estimated);
1380     return;
1381   }
1382 
1383   if (iid != vmIntrinsics::_none)
1384     success = compute_escape_for_intrinsic(iid);
1385   else {
1386     success = do_analysis();
1387   }
1388 
1389   // don't store interprocedural escape information if it introduces
1390   // dependencies or if method data is empty
1391   //
1392   if (!has_dependencies() && !methodData()->is_empty()) {
1393     for (i = 0; i < _arg_size; i++) {
1394       if (_arg_local.test(i)) {
1395         assert(_arg_stack.test(i), "inconsistent escape info");
1396         methodData()->set_arg_local(i);
1397         methodData()->set_arg_stack(i);
1398       } else if (_arg_stack.test(i)) {
1399         methodData()->set_arg_stack(i);
1400       }
1401       if (_arg_returned.test(i)) {
1402         methodData()->set_arg_returned(i);
1403       }
1404       methodData()->set_arg_modified(i, _arg_modified[i]);
1405     }
1406     if (_return_local) {
1407       methodData()->set_eflag(MethodData::return_local);
1408     }
1409     if (_return_allocated) {
1410       methodData()->set_eflag(MethodData::return_allocated);
1411     }
1412     if (_allocated_escapes) {
1413       methodData()->set_eflag(MethodData::allocated_escapes);
1414     }
1415     if (_unknown_modified) {
1416       methodData()->set_eflag(MethodData::unknown_modified);
1417     }
1418     methodData()->set_eflag(MethodData::estimated);
1419   }
1420 }
1421 
1422 void BCEscapeAnalyzer::read_escape_info() {
1423   assert(methodData()->has_escape_info(), "no escape info available");
1424 
1425   // read escape information from method descriptor
1426   for (int i = 0; i < _arg_size; i++) {
1427     if (methodData()->is_arg_local(i))
1428       _arg_local.set(i);
1429     if (methodData()->is_arg_stack(i))
1430       _arg_stack.set(i);
1431     if (methodData()->is_arg_returned(i))
1432       _arg_returned.set(i);
1433     _arg_modified[i] = methodData()->arg_modified(i);
1434   }
1435   _return_local = methodData()->eflag_set(MethodData::return_local);
1436   _return_allocated = methodData()->eflag_set(MethodData::return_allocated);
1437   _allocated_escapes = methodData()->eflag_set(MethodData::allocated_escapes);
1438   _unknown_modified = methodData()->eflag_set(MethodData::unknown_modified);
1439 
1440 }
1441 
1442 #ifndef PRODUCT
1443 void BCEscapeAnalyzer::dump() {
1444   tty->print("[EA] estimated escape information for");
1445   method()->print_short_name();
1446   tty->print_cr(has_dependencies() ? " (not stored)" : "");
1447   tty->print("     non-escaping args:      ");
1448   _arg_local.print();
1449   tty->print("     stack-allocatable args: ");
1450   _arg_stack.print();
1451   if (_return_local) {
1452     tty->print("     returned args:          ");
1453     _arg_returned.print();
1454   } else if (is_return_allocated()) {
1455     tty->print_cr("     return allocated value");
1456   } else {
1457     tty->print_cr("     return non-local value");
1458   }
1459   tty->print("     modified args: ");
1460   for (int i = 0; i < _arg_size; i++) {
1461     if (_arg_modified[i] == 0)
1462       tty->print("    0");
1463     else
1464       tty->print("    0x%x", _arg_modified[i]);
1465   }
1466   tty->cr();
1467   tty->print("     flags: ");
1468   if (_return_allocated)
1469     tty->print(" return_allocated");
1470   if (_allocated_escapes)
1471     tty->print(" allocated_escapes");
1472   if (_unknown_modified)
1473     tty->print(" unknown_modified");
1474   tty->cr();
1475 }
1476 #endif
1477 
1478 BCEscapeAnalyzer::BCEscapeAnalyzer(ciMethod* method, BCEscapeAnalyzer* parent)
1479     : _conservative(method == NULL || !EstimateArgEscape)
1480     , _arena(CURRENT_ENV->arena())
1481     , _method(method)
1482     , _methodData(method ? method->method_data() : NULL)
1483     , _arg_size(method ? method->arg_size() : 0)
1484     , _arg_local(_arena)
1485     , _arg_stack(_arena)
1486     , _arg_returned(_arena)
1487     , _dirty(_arena)
1488     , _return_local(false)
1489     , _return_allocated(false)
1490     , _allocated_escapes(false)
1491     , _unknown_modified(false)
1492     , _dependencies(_arena, 4, 0, NULL)
1493     , _parent(parent)
1494     , _level(parent == NULL ? 0 : parent->level() + 1) {
1495   if (!_conservative) {
1496     _arg_local.Clear();
1497     _arg_stack.Clear();
1498     _arg_returned.Clear();
1499     _dirty.Clear();
1500     Arena* arena = CURRENT_ENV->arena();
1501     _arg_modified = (uint *) arena->Amalloc(_arg_size * sizeof(uint));
1502     Copy::zero_to_bytes(_arg_modified, _arg_size * sizeof(uint));
1503 
1504     if (methodData() == NULL)
1505       return;
1506     if (methodData()->has_escape_info()) {
1507       TRACE_BCEA(2, tty->print_cr("[EA] Reading previous results for %s.%s",
1508                                   method->holder()->name()->as_utf8(),
1509                                   method->name()->as_utf8()));
1510       read_escape_info();
1511     } else {
1512       TRACE_BCEA(2, tty->print_cr("[EA] computing results for %s.%s",
1513                                   method->holder()->name()->as_utf8(),
1514                                   method->name()->as_utf8()));
1515 
1516       compute_escape_info();
1517       methodData()->update_escape_info();
1518     }
1519 #ifndef PRODUCT
1520     if (BCEATraceLevel >= 3) {
1521       // dump escape information
1522       dump();
1523     }
1524 #endif
1525   }
1526 }
1527 
1528 void BCEscapeAnalyzer::copy_dependencies(Dependencies *deps) {
1529   if (ciEnv::current()->jvmti_can_hotswap_or_post_breakpoint()) {
1530     // Also record evol dependencies so redefinition of the
1531     // callee will trigger recompilation.
1532     deps->assert_evol_method(method());
1533   }
1534   for (int i = 0; i < _dependencies.length(); i+=2) {
1535     ciKlass *k = _dependencies.at(i)->as_klass();
1536     ciMethod *m = _dependencies.at(i+1)->as_method();
1537     deps->assert_unique_concrete_method(k, m);
1538   }
1539 }
--- EOF ---