src/share/vm/ci/bcEscapeAnalyzer.cpp

Wed, 23 Oct 2013 12:40:23 +0200

author
roland
date
Wed, 23 Oct 2013 12:40:23 +0200
changeset 5991
b2ee5dc63353
parent 5436
c90c698831d7
child 6198
55fb97c4c58d
permissions
-rw-r--r--

8024070: C2 needs some form of type speculation
Summary: record unused type profile information with type system, propagate and use it.
Reviewed-by: kvn, twisti

     1 /*
     2  * Copyright (c) 2005, 2012, Oracle and/or its affiliates. All rights reserved.
     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
     4  *
     5  * This code is free software; you can redistribute it and/or modify it
     6  * under the terms of the GNU General Public License version 2 only, as
     7  * published by the Free Software Foundation.
     8  *
     9  * This code is distributed in the hope that it will be useful, but WITHOUT
    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    12  * version 2 for more details (a copy is included in the LICENSE file that
    13  * accompanied this code).
    14  *
    15  * You should have received a copy of the GNU General Public License version
    16  * 2 along with this work; if not, write to the Free Software Foundation,
    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
    18  *
    19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
    20  * or visit www.oracle.com if you need additional information or have any
    21  * questions.
    22  *
    23  */
    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 "utilities/bitMap.inline.hpp"
    36 #ifndef PRODUCT
    37   #define TRACE_BCEA(level, code)                                            \
    38     if (EstimateArgEscape && BCEATraceLevel >= level) {                        \
    39       code;                                                                  \
    40     }
    41 #else
    42   #define TRACE_BCEA(level, code)
    43 #endif
    45 // Maintain a map of which aguments a local variable or
    46 // stack slot may contain.  In addition to tracking
    47 // arguments, it tracks two special values, "allocated"
    48 // which represents any object allocated in the current
    49 // method, and "unknown" which is any other object.
    50 // Up to 30 arguments are handled, with the last one
    51 // representing summary information for any extra arguments
    52 class BCEscapeAnalyzer::ArgumentMap {
    53   uint  _bits;
    54   enum {MAXBIT = 29,
    55         ALLOCATED = 1,
    56         UNKNOWN = 2};
    58   uint int_to_bit(uint e) const {
    59     if (e > MAXBIT)
    60       e = MAXBIT;
    61     return (1 << (e + 2));
    62   }
    64 public:
    65   ArgumentMap()                         { _bits = 0;}
    66   void set_bits(uint bits)              { _bits = bits;}
    67   uint get_bits() const                 { return _bits;}
    68   void clear()                          { _bits = 0;}
    69   void set_all()                        { _bits = ~0u; }
    70   bool is_empty() const                 { return _bits == 0; }
    71   bool contains(uint var) const         { return (_bits & int_to_bit(var)) != 0; }
    72   bool is_singleton(uint var) const     { return (_bits == int_to_bit(var)); }
    73   bool contains_unknown() const         { return (_bits & UNKNOWN) != 0; }
    74   bool contains_allocated() const       { return (_bits & ALLOCATED) != 0; }
    75   bool contains_vars() const            { return (_bits & (((1 << MAXBIT) -1) << 2)) != 0; }
    76   void set(uint var)                    { _bits = int_to_bit(var); }
    77   void add(uint var)                    { _bits |= int_to_bit(var); }
    78   void add_unknown()                    { _bits = UNKNOWN; }
    79   void add_allocated()                  { _bits = ALLOCATED; }
    80   void set_union(const ArgumentMap &am)     { _bits |= am._bits; }
    81   void set_intersect(const ArgumentMap &am) { _bits |= am._bits; }
    82   void set_difference(const ArgumentMap &am) { _bits &=  ~am._bits; }
    83   void operator=(const ArgumentMap &am) { _bits = am._bits; }
    84   bool operator==(const ArgumentMap &am) { return _bits == am._bits; }
    85   bool operator!=(const ArgumentMap &am) { return _bits != am._bits; }
    86 };
    88 class BCEscapeAnalyzer::StateInfo {
    89 public:
    90   ArgumentMap *_vars;
    91   ArgumentMap *_stack;
    92   short _stack_height;
    93   short _max_stack;
    94   bool _initialized;
    95   ArgumentMap empty_map;
    97   StateInfo() {
    98     empty_map.clear();
    99   }
   101   ArgumentMap raw_pop()  { guarantee(_stack_height > 0, "stack underflow"); return _stack[--_stack_height]; }
   102   ArgumentMap  apop()    { return raw_pop(); }
   103   void spop()            { raw_pop(); }
   104   void lpop()            { spop(); spop(); }
   105   void raw_push(ArgumentMap i)   { guarantee(_stack_height < _max_stack, "stack overflow"); _stack[_stack_height++] = i; }
   106   void apush(ArgumentMap i)      { raw_push(i); }
   107   void spush()           { raw_push(empty_map); }
   108   void lpush()           { spush(); spush(); }
   110 };
   112 void BCEscapeAnalyzer::set_returned(ArgumentMap vars) {
   113   for (int i = 0; i < _arg_size; i++) {
   114     if (vars.contains(i))
   115       _arg_returned.set(i);
   116   }
   117   _return_local = _return_local && !(vars.contains_unknown() || vars.contains_allocated());
   118   _return_allocated = _return_allocated && vars.contains_allocated() && !(vars.contains_unknown() || vars.contains_vars());
   119 }
   121 // return true if any element of vars is an argument
   122 bool BCEscapeAnalyzer::is_argument(ArgumentMap vars) {
   123   for (int i = 0; i < _arg_size; i++) {
   124     if (vars.contains(i))
   125       return true;
   126   }
   127   return false;
   128 }
   130 // return true if any element of vars is an arg_stack argument
   131 bool BCEscapeAnalyzer::is_arg_stack(ArgumentMap vars){
   132   if (_conservative)
   133     return true;
   134   for (int i = 0; i < _arg_size; i++) {
   135     if (vars.contains(i) && _arg_stack.test(i))
   136       return true;
   137   }
   138   return false;
   139 }
   141 // return true if all argument elements of vars are returned
   142 bool BCEscapeAnalyzer::returns_all(ArgumentMap vars) {
   143   for (int i = 0; i < _arg_size; i++) {
   144     if (vars.contains(i) && !_arg_returned.test(i)) {
   145       return false;
   146     }
   147   }
   148   return true;
   149 }
   151 void BCEscapeAnalyzer::clear_bits(ArgumentMap vars, VectorSet &bm) {
   152   for (int i = 0; i < _arg_size; i++) {
   153     if (vars.contains(i)) {
   154       bm >>= i;
   155     }
   156   }
   157 }
   159 void BCEscapeAnalyzer::set_method_escape(ArgumentMap vars) {
   160   clear_bits(vars, _arg_local);
   161 }
   163 void BCEscapeAnalyzer::set_global_escape(ArgumentMap vars, bool merge) {
   164   clear_bits(vars, _arg_local);
   165   clear_bits(vars, _arg_stack);
   166   if (vars.contains_allocated())
   167     _allocated_escapes = true;
   169   if (merge && !vars.is_empty()) {
   170     // Merge new state into already processed block.
   171     // New state is not taken into account and
   172     // it may invalidate set_returned() result.
   173     if (vars.contains_unknown() || vars.contains_allocated()) {
   174       _return_local = false;
   175     }
   176     if (vars.contains_unknown() || vars.contains_vars()) {
   177       _return_allocated = false;
   178     }
   179     if (_return_local && vars.contains_vars() && !returns_all(vars)) {
   180       // Return result should be invalidated if args in new
   181       // state are not recorded in return state.
   182       _return_local = false;
   183     }
   184   }
   185 }
   187 void BCEscapeAnalyzer::set_dirty(ArgumentMap vars) {
   188   clear_bits(vars, _dirty);
   189 }
   191 void BCEscapeAnalyzer::set_modified(ArgumentMap vars, int offs, int size) {
   193   for (int i = 0; i < _arg_size; i++) {
   194     if (vars.contains(i)) {
   195       set_arg_modified(i, offs, size);
   196     }
   197   }
   198   if (vars.contains_unknown())
   199     _unknown_modified = true;
   200 }
   202 bool BCEscapeAnalyzer::is_recursive_call(ciMethod* callee) {
   203   for (BCEscapeAnalyzer* scope = this; scope != NULL; scope = scope->_parent) {
   204     if (scope->method() == callee) {
   205       return true;
   206     }
   207   }
   208   return false;
   209 }
   211 bool BCEscapeAnalyzer::is_arg_modified(int arg, int offset, int size_in_bytes) {
   212   if (offset == OFFSET_ANY)
   213     return _arg_modified[arg] != 0;
   214   assert(arg >= 0 && arg < _arg_size, "must be an argument.");
   215   bool modified = false;
   216   int l = offset / HeapWordSize;
   217   int h = round_to(offset + size_in_bytes, HeapWordSize) / HeapWordSize;
   218   if (l > ARG_OFFSET_MAX)
   219     l = ARG_OFFSET_MAX;
   220   if (h > ARG_OFFSET_MAX+1)
   221     h = ARG_OFFSET_MAX + 1;
   222   for (int i = l; i < h; i++) {
   223     modified = modified || (_arg_modified[arg] & (1 << i)) != 0;
   224   }
   225   return modified;
   226 }
   228 void BCEscapeAnalyzer::set_arg_modified(int arg, int offset, int size_in_bytes) {
   229   if (offset == OFFSET_ANY) {
   230     _arg_modified[arg] =  (uint) -1;
   231     return;
   232   }
   233   assert(arg >= 0 && arg < _arg_size, "must be an argument.");
   234   int l = offset / HeapWordSize;
   235   int h = round_to(offset + size_in_bytes, HeapWordSize) / HeapWordSize;
   236   if (l > ARG_OFFSET_MAX)
   237     l = ARG_OFFSET_MAX;
   238   if (h > ARG_OFFSET_MAX+1)
   239     h = ARG_OFFSET_MAX + 1;
   240   for (int i = l; i < h; i++) {
   241     _arg_modified[arg] |= (1 << i);
   242   }
   243 }
   245 void BCEscapeAnalyzer::invoke(StateInfo &state, Bytecodes::Code code, ciMethod* target, ciKlass* holder) {
   246   int i;
   248   // retrieve information about the callee
   249   ciInstanceKlass* klass = target->holder();
   250   ciInstanceKlass* calling_klass = method()->holder();
   251   ciInstanceKlass* callee_holder = ciEnv::get_instance_klass_for_declared_method_holder(holder);
   252   ciInstanceKlass* actual_recv = callee_holder;
   254   // Some methods are obviously bindable without any type checks so
   255   // convert them directly to an invokespecial or invokestatic.
   256   if (target->is_loaded() && !target->is_abstract() && target->can_be_statically_bound()) {
   257     switch (code) {
   258     case Bytecodes::_invokevirtual:
   259       code = Bytecodes::_invokespecial;
   260       break;
   261     case Bytecodes::_invokehandle:
   262       code = target->is_static() ? Bytecodes::_invokestatic : Bytecodes::_invokespecial;
   263       break;
   264     }
   265   }
   267   // compute size of arguments
   268   int arg_size = target->invoke_arg_size(code);
   269   int arg_base = MAX2(state._stack_height - arg_size, 0);
   271   // direct recursive calls are skipped if they can be bound statically without introducing
   272   // dependencies and if parameters are passed at the same position as in the current method
   273   // other calls are skipped if there are no unescaped arguments passed to them
   274   bool directly_recursive = (method() == target) &&
   275                (code != Bytecodes::_invokevirtual || target->is_final_method() || state._stack[arg_base] .is_empty());
   277   // check if analysis of callee can safely be skipped
   278   bool skip_callee = true;
   279   for (i = state._stack_height - 1; i >= arg_base && skip_callee; i--) {
   280     ArgumentMap arg = state._stack[i];
   281     skip_callee = !is_argument(arg) || !is_arg_stack(arg) || (directly_recursive && arg.is_singleton(i - arg_base));
   282   }
   283   // For now we conservatively skip invokedynamic.
   284   if (code == Bytecodes::_invokedynamic) {
   285     skip_callee = true;
   286   }
   287   if (skip_callee) {
   288     TRACE_BCEA(3, tty->print_cr("[EA] skipping method %s::%s", holder->name()->as_utf8(), target->name()->as_utf8()));
   289     for (i = 0; i < arg_size; i++) {
   290       set_method_escape(state.raw_pop());
   291     }
   292     _unknown_modified = true;  // assume the worst since we don't analyze the called method
   293     return;
   294   }
   296   // determine actual method (use CHA if necessary)
   297   ciMethod* inline_target = NULL;
   298   if (target->is_loaded() && klass->is_loaded()
   299       && (klass->is_initialized() || klass->is_interface() && target->holder()->is_initialized())
   300       && target->is_loaded()) {
   301     if (code == Bytecodes::_invokestatic
   302         || code == Bytecodes::_invokespecial
   303         || code == Bytecodes::_invokevirtual && target->is_final_method()) {
   304       inline_target = target;
   305     } else {
   306       inline_target = target->find_monomorphic_target(calling_klass, callee_holder, actual_recv);
   307     }
   308   }
   310   if (inline_target != NULL && !is_recursive_call(inline_target)) {
   311     // analyze callee
   312     BCEscapeAnalyzer analyzer(inline_target, this);
   314     // adjust escape state of actual parameters
   315     bool must_record_dependencies = false;
   316     for (i = arg_size - 1; i >= 0; i--) {
   317       ArgumentMap arg = state.raw_pop();
   318       if (!is_argument(arg))
   319         continue;
   320       for (int j = 0; j < _arg_size; j++) {
   321         if (arg.contains(j)) {
   322           _arg_modified[j] |= analyzer._arg_modified[i];
   323         }
   324       }
   325       if (!is_arg_stack(arg)) {
   326         // arguments have already been recognized as escaping
   327       } else if (analyzer.is_arg_stack(i) && !analyzer.is_arg_returned(i)) {
   328         set_method_escape(arg);
   329         must_record_dependencies = true;
   330       } else {
   331         set_global_escape(arg);
   332       }
   333     }
   334     _unknown_modified = _unknown_modified || analyzer.has_non_arg_side_affects();
   336     // record dependencies if at least one parameter retained stack-allocatable
   337     if (must_record_dependencies) {
   338       if (code == Bytecodes::_invokeinterface || code == Bytecodes::_invokevirtual && !target->is_final_method()) {
   339         _dependencies.append(actual_recv);
   340         _dependencies.append(inline_target);
   341       }
   342       _dependencies.appendAll(analyzer.dependencies());
   343     }
   344   } else {
   345     TRACE_BCEA(1, tty->print_cr("[EA] virtual method %s is not monomorphic.",
   346                                 target->name()->as_utf8()));
   347     // conservatively mark all actual parameters as escaping globally
   348     for (i = 0; i < arg_size; i++) {
   349       ArgumentMap arg = state.raw_pop();
   350       if (!is_argument(arg))
   351         continue;
   352       set_modified(arg, OFFSET_ANY, type2size[T_INT]*HeapWordSize);
   353       set_global_escape(arg);
   354     }
   355     _unknown_modified = true;  // assume the worst since we don't know the called method
   356   }
   357 }
   359 bool BCEscapeAnalyzer::contains(uint arg_set1, uint arg_set2) {
   360   return ((~arg_set1) | arg_set2) == 0;
   361 }
   364 void BCEscapeAnalyzer::iterate_one_block(ciBlock *blk, StateInfo &state, GrowableArray<ciBlock *> &successors) {
   366   blk->set_processed();
   367   ciBytecodeStream s(method());
   368   int limit_bci = blk->limit_bci();
   369   bool fall_through = false;
   370   ArgumentMap allocated_obj;
   371   allocated_obj.add_allocated();
   372   ArgumentMap unknown_obj;
   373   unknown_obj.add_unknown();
   374   ArgumentMap empty_map;
   376   s.reset_to_bci(blk->start_bci());
   377   while (s.next() != ciBytecodeStream::EOBC() && s.cur_bci() < limit_bci) {
   378     fall_through = true;
   379     switch (s.cur_bc()) {
   380       case Bytecodes::_nop:
   381         break;
   382       case Bytecodes::_aconst_null:
   383         state.apush(unknown_obj);
   384         break;
   385       case Bytecodes::_iconst_m1:
   386       case Bytecodes::_iconst_0:
   387       case Bytecodes::_iconst_1:
   388       case Bytecodes::_iconst_2:
   389       case Bytecodes::_iconst_3:
   390       case Bytecodes::_iconst_4:
   391       case Bytecodes::_iconst_5:
   392       case Bytecodes::_fconst_0:
   393       case Bytecodes::_fconst_1:
   394       case Bytecodes::_fconst_2:
   395       case Bytecodes::_bipush:
   396       case Bytecodes::_sipush:
   397         state.spush();
   398         break;
   399       case Bytecodes::_lconst_0:
   400       case Bytecodes::_lconst_1:
   401       case Bytecodes::_dconst_0:
   402       case Bytecodes::_dconst_1:
   403         state.lpush();
   404         break;
   405       case Bytecodes::_ldc:
   406       case Bytecodes::_ldc_w:
   407       case Bytecodes::_ldc2_w:
   408       {
   409         // Avoid calling get_constant() which will try to allocate
   410         // unloaded constant. We need only constant's type.
   411         int index = s.get_constant_pool_index();
   412         constantTag tag = s.get_constant_pool_tag(index);
   413         if (tag.is_long() || tag.is_double()) {
   414           // Only longs and doubles use 2 stack slots.
   415           state.lpush();
   416         } else if (tag.basic_type() == T_OBJECT) {
   417           state.apush(unknown_obj);
   418         } else {
   419           state.spush();
   420         }
   421         break;
   422       }
   423       case Bytecodes::_aload:
   424         state.apush(state._vars[s.get_index()]);
   425         break;
   426       case Bytecodes::_iload:
   427       case Bytecodes::_fload:
   428       case Bytecodes::_iload_0:
   429       case Bytecodes::_iload_1:
   430       case Bytecodes::_iload_2:
   431       case Bytecodes::_iload_3:
   432       case Bytecodes::_fload_0:
   433       case Bytecodes::_fload_1:
   434       case Bytecodes::_fload_2:
   435       case Bytecodes::_fload_3:
   436         state.spush();
   437         break;
   438       case Bytecodes::_lload:
   439       case Bytecodes::_dload:
   440       case Bytecodes::_lload_0:
   441       case Bytecodes::_lload_1:
   442       case Bytecodes::_lload_2:
   443       case Bytecodes::_lload_3:
   444       case Bytecodes::_dload_0:
   445       case Bytecodes::_dload_1:
   446       case Bytecodes::_dload_2:
   447       case Bytecodes::_dload_3:
   448         state.lpush();
   449         break;
   450       case Bytecodes::_aload_0:
   451         state.apush(state._vars[0]);
   452         break;
   453       case Bytecodes::_aload_1:
   454         state.apush(state._vars[1]);
   455         break;
   456       case Bytecodes::_aload_2:
   457         state.apush(state._vars[2]);
   458         break;
   459       case Bytecodes::_aload_3:
   460         state.apush(state._vars[3]);
   461         break;
   462       case Bytecodes::_iaload:
   463       case Bytecodes::_faload:
   464       case Bytecodes::_baload:
   465       case Bytecodes::_caload:
   466       case Bytecodes::_saload:
   467         state.spop();
   468         set_method_escape(state.apop());
   469         state.spush();
   470         break;
   471       case Bytecodes::_laload:
   472       case Bytecodes::_daload:
   473         state.spop();
   474         set_method_escape(state.apop());
   475         state.lpush();
   476         break;
   477       case Bytecodes::_aaload:
   478         { state.spop();
   479           ArgumentMap array = state.apop();
   480           set_method_escape(array);
   481           state.apush(unknown_obj);
   482           set_dirty(array);
   483         }
   484         break;
   485       case Bytecodes::_istore:
   486       case Bytecodes::_fstore:
   487       case Bytecodes::_istore_0:
   488       case Bytecodes::_istore_1:
   489       case Bytecodes::_istore_2:
   490       case Bytecodes::_istore_3:
   491       case Bytecodes::_fstore_0:
   492       case Bytecodes::_fstore_1:
   493       case Bytecodes::_fstore_2:
   494       case Bytecodes::_fstore_3:
   495         state.spop();
   496         break;
   497       case Bytecodes::_lstore:
   498       case Bytecodes::_dstore:
   499       case Bytecodes::_lstore_0:
   500       case Bytecodes::_lstore_1:
   501       case Bytecodes::_lstore_2:
   502       case Bytecodes::_lstore_3:
   503       case Bytecodes::_dstore_0:
   504       case Bytecodes::_dstore_1:
   505       case Bytecodes::_dstore_2:
   506       case Bytecodes::_dstore_3:
   507         state.lpop();
   508         break;
   509       case Bytecodes::_astore:
   510         state._vars[s.get_index()] = state.apop();
   511         break;
   512       case Bytecodes::_astore_0:
   513         state._vars[0] = state.apop();
   514         break;
   515       case Bytecodes::_astore_1:
   516         state._vars[1] = state.apop();
   517         break;
   518       case Bytecodes::_astore_2:
   519         state._vars[2] = state.apop();
   520         break;
   521       case Bytecodes::_astore_3:
   522         state._vars[3] = state.apop();
   523         break;
   524       case Bytecodes::_iastore:
   525       case Bytecodes::_fastore:
   526       case Bytecodes::_bastore:
   527       case Bytecodes::_castore:
   528       case Bytecodes::_sastore:
   529       {
   530         state.spop();
   531         state.spop();
   532         ArgumentMap arr = state.apop();
   533         set_method_escape(arr);
   534         set_modified(arr, OFFSET_ANY, type2size[T_INT]*HeapWordSize);
   535         break;
   536       }
   537       case Bytecodes::_lastore:
   538       case Bytecodes::_dastore:
   539       {
   540         state.lpop();
   541         state.spop();
   542         ArgumentMap arr = state.apop();
   543         set_method_escape(arr);
   544         set_modified(arr, OFFSET_ANY, type2size[T_LONG]*HeapWordSize);
   545         break;
   546       }
   547       case Bytecodes::_aastore:
   548       {
   549         set_global_escape(state.apop());
   550         state.spop();
   551         ArgumentMap arr = state.apop();
   552         set_modified(arr, OFFSET_ANY, type2size[T_OBJECT]*HeapWordSize);
   553         break;
   554       }
   555       case Bytecodes::_pop:
   556         state.raw_pop();
   557         break;
   558       case Bytecodes::_pop2:
   559         state.raw_pop();
   560         state.raw_pop();
   561         break;
   562       case Bytecodes::_dup:
   563         { ArgumentMap w1 = state.raw_pop();
   564           state.raw_push(w1);
   565           state.raw_push(w1);
   566         }
   567         break;
   568       case Bytecodes::_dup_x1:
   569         { ArgumentMap w1 = state.raw_pop();
   570           ArgumentMap w2 = state.raw_pop();
   571           state.raw_push(w1);
   572           state.raw_push(w2);
   573           state.raw_push(w1);
   574         }
   575         break;
   576       case Bytecodes::_dup_x2:
   577         { ArgumentMap w1 = state.raw_pop();
   578           ArgumentMap w2 = state.raw_pop();
   579           ArgumentMap w3 = state.raw_pop();
   580           state.raw_push(w1);
   581           state.raw_push(w3);
   582           state.raw_push(w2);
   583           state.raw_push(w1);
   584         }
   585         break;
   586       case Bytecodes::_dup2:
   587         { ArgumentMap w1 = state.raw_pop();
   588           ArgumentMap w2 = state.raw_pop();
   589           state.raw_push(w2);
   590           state.raw_push(w1);
   591           state.raw_push(w2);
   592           state.raw_push(w1);
   593         }
   594         break;
   595       case Bytecodes::_dup2_x1:
   596         { ArgumentMap w1 = state.raw_pop();
   597           ArgumentMap w2 = state.raw_pop();
   598           ArgumentMap w3 = state.raw_pop();
   599           state.raw_push(w2);
   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_x2:
   607         { ArgumentMap w1 = state.raw_pop();
   608           ArgumentMap w2 = state.raw_pop();
   609           ArgumentMap w3 = state.raw_pop();
   610           ArgumentMap w4 = state.raw_pop();
   611           state.raw_push(w2);
   612           state.raw_push(w1);
   613           state.raw_push(w4);
   614           state.raw_push(w3);
   615           state.raw_push(w2);
   616           state.raw_push(w1);
   617         }
   618         break;
   619       case Bytecodes::_swap:
   620         { ArgumentMap w1 = state.raw_pop();
   621           ArgumentMap w2 = state.raw_pop();
   622           state.raw_push(w1);
   623           state.raw_push(w2);
   624         }
   625         break;
   626       case Bytecodes::_iadd:
   627       case Bytecodes::_fadd:
   628       case Bytecodes::_isub:
   629       case Bytecodes::_fsub:
   630       case Bytecodes::_imul:
   631       case Bytecodes::_fmul:
   632       case Bytecodes::_idiv:
   633       case Bytecodes::_fdiv:
   634       case Bytecodes::_irem:
   635       case Bytecodes::_frem:
   636       case Bytecodes::_iand:
   637       case Bytecodes::_ior:
   638       case Bytecodes::_ixor:
   639         state.spop();
   640         state.spop();
   641         state.spush();
   642         break;
   643       case Bytecodes::_ladd:
   644       case Bytecodes::_dadd:
   645       case Bytecodes::_lsub:
   646       case Bytecodes::_dsub:
   647       case Bytecodes::_lmul:
   648       case Bytecodes::_dmul:
   649       case Bytecodes::_ldiv:
   650       case Bytecodes::_ddiv:
   651       case Bytecodes::_lrem:
   652       case Bytecodes::_drem:
   653       case Bytecodes::_land:
   654       case Bytecodes::_lor:
   655       case Bytecodes::_lxor:
   656         state.lpop();
   657         state.lpop();
   658         state.lpush();
   659         break;
   660       case Bytecodes::_ishl:
   661       case Bytecodes::_ishr:
   662       case Bytecodes::_iushr:
   663         state.spop();
   664         state.spop();
   665         state.spush();
   666         break;
   667       case Bytecodes::_lshl:
   668       case Bytecodes::_lshr:
   669       case Bytecodes::_lushr:
   670         state.spop();
   671         state.lpop();
   672         state.lpush();
   673         break;
   674       case Bytecodes::_ineg:
   675       case Bytecodes::_fneg:
   676         state.spop();
   677         state.spush();
   678         break;
   679       case Bytecodes::_lneg:
   680       case Bytecodes::_dneg:
   681         state.lpop();
   682         state.lpush();
   683         break;
   684       case Bytecodes::_iinc:
   685         break;
   686       case Bytecodes::_i2l:
   687       case Bytecodes::_i2d:
   688       case Bytecodes::_f2l:
   689       case Bytecodes::_f2d:
   690         state.spop();
   691         state.lpush();
   692         break;
   693       case Bytecodes::_i2f:
   694       case Bytecodes::_f2i:
   695         state.spop();
   696         state.spush();
   697         break;
   698       case Bytecodes::_l2i:
   699       case Bytecodes::_l2f:
   700       case Bytecodes::_d2i:
   701       case Bytecodes::_d2f:
   702         state.lpop();
   703         state.spush();
   704         break;
   705       case Bytecodes::_l2d:
   706       case Bytecodes::_d2l:
   707         state.lpop();
   708         state.lpush();
   709         break;
   710       case Bytecodes::_i2b:
   711       case Bytecodes::_i2c:
   712       case Bytecodes::_i2s:
   713         state.spop();
   714         state.spush();
   715         break;
   716       case Bytecodes::_lcmp:
   717       case Bytecodes::_dcmpl:
   718       case Bytecodes::_dcmpg:
   719         state.lpop();
   720         state.lpop();
   721         state.spush();
   722         break;
   723       case Bytecodes::_fcmpl:
   724       case Bytecodes::_fcmpg:
   725         state.spop();
   726         state.spop();
   727         state.spush();
   728         break;
   729       case Bytecodes::_ifeq:
   730       case Bytecodes::_ifne:
   731       case Bytecodes::_iflt:
   732       case Bytecodes::_ifge:
   733       case Bytecodes::_ifgt:
   734       case Bytecodes::_ifle:
   735       {
   736         state.spop();
   737         int dest_bci = s.get_dest();
   738         assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
   739         assert(s.next_bci() == limit_bci, "branch must end block");
   740         successors.push(_methodBlocks->block_containing(dest_bci));
   741         break;
   742       }
   743       case Bytecodes::_if_icmpeq:
   744       case Bytecodes::_if_icmpne:
   745       case Bytecodes::_if_icmplt:
   746       case Bytecodes::_if_icmpge:
   747       case Bytecodes::_if_icmpgt:
   748       case Bytecodes::_if_icmple:
   749       {
   750         state.spop();
   751         state.spop();
   752         int dest_bci = s.get_dest();
   753         assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
   754         assert(s.next_bci() == limit_bci, "branch must end block");
   755         successors.push(_methodBlocks->block_containing(dest_bci));
   756         break;
   757       }
   758       case Bytecodes::_if_acmpeq:
   759       case Bytecodes::_if_acmpne:
   760       {
   761         set_method_escape(state.apop());
   762         set_method_escape(state.apop());
   763         int dest_bci = s.get_dest();
   764         assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
   765         assert(s.next_bci() == limit_bci, "branch must end block");
   766         successors.push(_methodBlocks->block_containing(dest_bci));
   767         break;
   768       }
   769       case Bytecodes::_goto:
   770       {
   771         int dest_bci = s.get_dest();
   772         assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
   773         assert(s.next_bci() == limit_bci, "branch must end block");
   774         successors.push(_methodBlocks->block_containing(dest_bci));
   775         fall_through = false;
   776         break;
   777       }
   778       case Bytecodes::_jsr:
   779       {
   780         int dest_bci = s.get_dest();
   781         assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
   782         assert(s.next_bci() == limit_bci, "branch must end block");
   783         state.apush(empty_map);
   784         successors.push(_methodBlocks->block_containing(dest_bci));
   785         fall_through = false;
   786         break;
   787       }
   788       case Bytecodes::_ret:
   789         // we don't track  the destination of a "ret" instruction
   790         assert(s.next_bci() == limit_bci, "branch must end block");
   791         fall_through = false;
   792         break;
   793       case Bytecodes::_return:
   794         assert(s.next_bci() == limit_bci, "return must end block");
   795         fall_through = false;
   796         break;
   797       case Bytecodes::_tableswitch:
   798         {
   799           state.spop();
   800           Bytecode_tableswitch sw(&s);
   801           int len = sw.length();
   802           int dest_bci;
   803           for (int i = 0; i < len; i++) {
   804             dest_bci = s.cur_bci() + sw.dest_offset_at(i);
   805             assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
   806             successors.push(_methodBlocks->block_containing(dest_bci));
   807           }
   808           dest_bci = s.cur_bci() + sw.default_offset();
   809           assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
   810           successors.push(_methodBlocks->block_containing(dest_bci));
   811           assert(s.next_bci() == limit_bci, "branch must end block");
   812           fall_through = false;
   813           break;
   814         }
   815       case Bytecodes::_lookupswitch:
   816         {
   817           state.spop();
   818           Bytecode_lookupswitch sw(&s);
   819           int len = sw.number_of_pairs();
   820           int dest_bci;
   821           for (int i = 0; i < len; i++) {
   822             dest_bci = s.cur_bci() + sw.pair_at(i).offset();
   823             assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
   824             successors.push(_methodBlocks->block_containing(dest_bci));
   825           }
   826           dest_bci = s.cur_bci() + sw.default_offset();
   827           assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
   828           successors.push(_methodBlocks->block_containing(dest_bci));
   829           fall_through = false;
   830           break;
   831         }
   832       case Bytecodes::_ireturn:
   833       case Bytecodes::_freturn:
   834         state.spop();
   835         fall_through = false;
   836         break;
   837       case Bytecodes::_lreturn:
   838       case Bytecodes::_dreturn:
   839         state.lpop();
   840         fall_through = false;
   841         break;
   842       case Bytecodes::_areturn:
   843         set_returned(state.apop());
   844         fall_through = false;
   845         break;
   846       case Bytecodes::_getstatic:
   847       case Bytecodes::_getfield:
   848         { bool ignored_will_link;
   849           ciField* field = s.get_field(ignored_will_link);
   850           BasicType field_type = field->type()->basic_type();
   851           if (s.cur_bc() != Bytecodes::_getstatic) {
   852             set_method_escape(state.apop());
   853           }
   854           if (field_type == T_OBJECT || field_type == T_ARRAY) {
   855             state.apush(unknown_obj);
   856           } else if (type2size[field_type] == 1) {
   857             state.spush();
   858           } else {
   859             state.lpush();
   860           }
   861         }
   862         break;
   863       case Bytecodes::_putstatic:
   864       case Bytecodes::_putfield:
   865         { bool will_link;
   866           ciField* field = s.get_field(will_link);
   867           BasicType field_type = field->type()->basic_type();
   868           if (field_type == T_OBJECT || field_type == T_ARRAY) {
   869             set_global_escape(state.apop());
   870           } else if (type2size[field_type] == 1) {
   871             state.spop();
   872           } else {
   873             state.lpop();
   874           }
   875           if (s.cur_bc() != Bytecodes::_putstatic) {
   876             ArgumentMap p = state.apop();
   877             set_method_escape(p);
   878             set_modified(p, will_link ? field->offset() : OFFSET_ANY, type2size[field_type]*HeapWordSize);
   879           }
   880         }
   881         break;
   882       case Bytecodes::_invokevirtual:
   883       case Bytecodes::_invokespecial:
   884       case Bytecodes::_invokestatic:
   885       case Bytecodes::_invokedynamic:
   886       case Bytecodes::_invokeinterface:
   887         { bool ignored_will_link;
   888           ciSignature* declared_signature = NULL;
   889           ciMethod* target = s.get_method(ignored_will_link, &declared_signature);
   890           ciKlass*  holder = s.get_declared_method_holder();
   891           assert(declared_signature != NULL, "cannot be null");
   892           // Push appendix argument, if one.
   893           if (s.has_appendix()) {
   894             state.apush(unknown_obj);
   895           }
   896           // Pass in raw bytecode because we need to see invokehandle instructions.
   897           invoke(state, s.cur_bc_raw(), target, holder);
   898           // We are using the return type of the declared signature here because
   899           // it might be a more concrete type than the one from the target (for
   900           // e.g. invokedynamic and invokehandle).
   901           ciType* return_type = declared_signature->return_type();
   902           if (!return_type->is_primitive_type()) {
   903             state.apush(unknown_obj);
   904           } else if (return_type->is_one_word()) {
   905             state.spush();
   906           } else if (return_type->is_two_word()) {
   907             state.lpush();
   908           }
   909         }
   910         break;
   911       case Bytecodes::_new:
   912         state.apush(allocated_obj);
   913         break;
   914       case Bytecodes::_newarray:
   915       case Bytecodes::_anewarray:
   916         state.spop();
   917         state.apush(allocated_obj);
   918         break;
   919       case Bytecodes::_multianewarray:
   920         { int i = s.cur_bcp()[3];
   921           while (i-- > 0) state.spop();
   922           state.apush(allocated_obj);
   923         }
   924         break;
   925       case Bytecodes::_arraylength:
   926         set_method_escape(state.apop());
   927         state.spush();
   928         break;
   929       case Bytecodes::_athrow:
   930         set_global_escape(state.apop());
   931         fall_through = false;
   932         break;
   933       case Bytecodes::_checkcast:
   934         { ArgumentMap obj = state.apop();
   935           set_method_escape(obj);
   936           state.apush(obj);
   937         }
   938         break;
   939       case Bytecodes::_instanceof:
   940         set_method_escape(state.apop());
   941         state.spush();
   942         break;
   943       case Bytecodes::_monitorenter:
   944       case Bytecodes::_monitorexit:
   945         state.apop();
   946         break;
   947       case Bytecodes::_wide:
   948         ShouldNotReachHere();
   949         break;
   950       case Bytecodes::_ifnull:
   951       case Bytecodes::_ifnonnull:
   952       {
   953         set_method_escape(state.apop());
   954         int dest_bci = s.get_dest();
   955         assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
   956         assert(s.next_bci() == limit_bci, "branch must end block");
   957         successors.push(_methodBlocks->block_containing(dest_bci));
   958         break;
   959       }
   960       case Bytecodes::_goto_w:
   961       {
   962         int dest_bci = s.get_far_dest();
   963         assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
   964         assert(s.next_bci() == limit_bci, "branch must end block");
   965         successors.push(_methodBlocks->block_containing(dest_bci));
   966         fall_through = false;
   967         break;
   968       }
   969       case Bytecodes::_jsr_w:
   970       {
   971         int dest_bci = s.get_far_dest();
   972         assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
   973         assert(s.next_bci() == limit_bci, "branch must end block");
   974         state.apush(empty_map);
   975         successors.push(_methodBlocks->block_containing(dest_bci));
   976         fall_through = false;
   977         break;
   978       }
   979       case Bytecodes::_breakpoint:
   980         break;
   981       default:
   982         ShouldNotReachHere();
   983         break;
   984     }
   986   }
   987   if (fall_through) {
   988     int fall_through_bci = s.cur_bci();
   989     if (fall_through_bci < _method->code_size()) {
   990       assert(_methodBlocks->is_block_start(fall_through_bci), "must fall through to block start.");
   991       successors.push(_methodBlocks->block_containing(fall_through_bci));
   992     }
   993   }
   994 }
   996 void BCEscapeAnalyzer::merge_block_states(StateInfo *blockstates, ciBlock *dest, StateInfo *s_state) {
   997   StateInfo *d_state = blockstates + dest->index();
   998   int nlocals = _method->max_locals();
  1000   // exceptions may cause transfer of control to handlers in the middle of a
  1001   // block, so we don't merge the incoming state of exception handlers
  1002   if (dest->is_handler())
  1003     return;
  1004   if (!d_state->_initialized ) {
  1005     // destination not initialized, just copy
  1006     for (int i = 0; i < nlocals; i++) {
  1007       d_state->_vars[i] = s_state->_vars[i];
  1009     for (int i = 0; i < s_state->_stack_height; i++) {
  1010       d_state->_stack[i] = s_state->_stack[i];
  1012     d_state->_stack_height = s_state->_stack_height;
  1013     d_state->_max_stack = s_state->_max_stack;
  1014     d_state->_initialized = true;
  1015   } else if (!dest->processed()) {
  1016     // we have not yet walked the bytecodes of dest, we can merge
  1017     // the states
  1018     assert(d_state->_stack_height == s_state->_stack_height, "computed stack heights must match");
  1019     for (int i = 0; i < nlocals; i++) {
  1020       d_state->_vars[i].set_union(s_state->_vars[i]);
  1022     for (int i = 0; i < s_state->_stack_height; i++) {
  1023       d_state->_stack[i].set_union(s_state->_stack[i]);
  1025   } else {
  1026     // the bytecodes of dest have already been processed, mark any
  1027     // arguments in the source state which are not in the dest state
  1028     // as global escape.
  1029     // Future refinement:  we only need to mark these variable to the
  1030     // maximum escape of any variables in dest state
  1031     assert(d_state->_stack_height == s_state->_stack_height, "computed stack heights must match");
  1032     ArgumentMap extra_vars;
  1033     for (int i = 0; i < nlocals; i++) {
  1034       ArgumentMap t;
  1035       t = s_state->_vars[i];
  1036       t.set_difference(d_state->_vars[i]);
  1037       extra_vars.set_union(t);
  1039     for (int i = 0; i < s_state->_stack_height; i++) {
  1040       ArgumentMap t;
  1041       //extra_vars |= !d_state->_vars[i] & s_state->_vars[i];
  1042       t.clear();
  1043       t = s_state->_stack[i];
  1044       t.set_difference(d_state->_stack[i]);
  1045       extra_vars.set_union(t);
  1047     set_global_escape(extra_vars, true);
  1051 void BCEscapeAnalyzer::iterate_blocks(Arena *arena) {
  1052   int numblocks = _methodBlocks->num_blocks();
  1053   int stkSize   = _method->max_stack();
  1054   int numLocals = _method->max_locals();
  1055   StateInfo state;
  1057   int datacount = (numblocks + 1) * (stkSize + numLocals);
  1058   int datasize = datacount * sizeof(ArgumentMap);
  1059   StateInfo *blockstates = (StateInfo *) arena->Amalloc(numblocks * sizeof(StateInfo));
  1060   ArgumentMap *statedata  = (ArgumentMap *) arena->Amalloc(datasize);
  1061   for (int i = 0; i < datacount; i++) ::new ((void*)&statedata[i]) ArgumentMap();
  1062   ArgumentMap *dp = statedata;
  1063   state._vars = dp;
  1064   dp += numLocals;
  1065   state._stack = dp;
  1066   dp += stkSize;
  1067   state._initialized = false;
  1068   state._max_stack = stkSize;
  1069   for (int i = 0; i < numblocks; i++) {
  1070     blockstates[i]._vars = dp;
  1071     dp += numLocals;
  1072     blockstates[i]._stack = dp;
  1073     dp += stkSize;
  1074     blockstates[i]._initialized = false;
  1075     blockstates[i]._stack_height = 0;
  1076     blockstates[i]._max_stack  = stkSize;
  1078   GrowableArray<ciBlock *> worklist(arena, numblocks / 4, 0, NULL);
  1079   GrowableArray<ciBlock *> successors(arena, 4, 0, NULL);
  1081   _methodBlocks->clear_processed();
  1083   // initialize block 0 state from method signature
  1084   ArgumentMap allVars;   // all oop arguments to method
  1085   ciSignature* sig = method()->signature();
  1086   int j = 0;
  1087   ciBlock* first_blk = _methodBlocks->block_containing(0);
  1088   int fb_i = first_blk->index();
  1089   if (!method()->is_static()) {
  1090     // record information for "this"
  1091     blockstates[fb_i]._vars[j].set(j);
  1092     allVars.add(j);
  1093     j++;
  1095   for (int i = 0; i < sig->count(); i++) {
  1096     ciType* t = sig->type_at(i);
  1097     if (!t->is_primitive_type()) {
  1098       blockstates[fb_i]._vars[j].set(j);
  1099       allVars.add(j);
  1101     j += t->size();
  1103   blockstates[fb_i]._initialized = true;
  1104   assert(j == _arg_size, "just checking");
  1106   ArgumentMap unknown_map;
  1107   unknown_map.add_unknown();
  1109   worklist.push(first_blk);
  1110   while(worklist.length() > 0) {
  1111     ciBlock *blk = worklist.pop();
  1112     StateInfo *blkState = blockstates + blk->index();
  1113     if (blk->is_handler() || blk->is_ret_target()) {
  1114       // for an exception handler or a target of a ret instruction, we assume the worst case,
  1115       // that any variable could contain any argument
  1116       for (int i = 0; i < numLocals; i++) {
  1117         state._vars[i] = allVars;
  1119       if (blk->is_handler()) {
  1120         state._stack_height = 1;
  1121       } else {
  1122         state._stack_height = blkState->_stack_height;
  1124       for (int i = 0; i < state._stack_height; i++) {
  1125 // ??? should this be unknown_map ???
  1126         state._stack[i] = allVars;
  1128     } else {
  1129       for (int i = 0; i < numLocals; i++) {
  1130         state._vars[i] = blkState->_vars[i];
  1132       for (int i = 0; i < blkState->_stack_height; i++) {
  1133         state._stack[i] = blkState->_stack[i];
  1135       state._stack_height = blkState->_stack_height;
  1137     iterate_one_block(blk, state, successors);
  1138     // if this block has any exception handlers, push them
  1139     // onto successor list
  1140     if (blk->has_handler()) {
  1141       DEBUG_ONLY(int handler_count = 0;)
  1142       int blk_start = blk->start_bci();
  1143       int blk_end = blk->limit_bci();
  1144       for (int i = 0; i < numblocks; i++) {
  1145         ciBlock *b = _methodBlocks->block(i);
  1146         if (b->is_handler()) {
  1147           int ex_start = b->ex_start_bci();
  1148           int ex_end = b->ex_limit_bci();
  1149           if ((ex_start >= blk_start && ex_start < blk_end) ||
  1150               (ex_end > blk_start && ex_end <= blk_end)) {
  1151             successors.push(b);
  1153           DEBUG_ONLY(handler_count++;)
  1156       assert(handler_count > 0, "must find at least one handler");
  1158     // merge computed variable state with successors
  1159     while(successors.length() > 0) {
  1160       ciBlock *succ = successors.pop();
  1161       merge_block_states(blockstates, succ, &state);
  1162       if (!succ->processed())
  1163         worklist.push(succ);
  1168 bool BCEscapeAnalyzer::do_analysis() {
  1169   Arena* arena = CURRENT_ENV->arena();
  1170   // identify basic blocks
  1171   _methodBlocks = _method->get_method_blocks();
  1173   iterate_blocks(arena);
  1174   // TEMPORARY
  1175   return true;
  1178 vmIntrinsics::ID BCEscapeAnalyzer::known_intrinsic() {
  1179   vmIntrinsics::ID iid = method()->intrinsic_id();
  1181   if (iid == vmIntrinsics::_getClass ||
  1182       iid ==  vmIntrinsics::_fillInStackTrace ||
  1183       iid == vmIntrinsics::_hashCode)
  1184     return iid;
  1185   else
  1186     return vmIntrinsics::_none;
  1189 bool BCEscapeAnalyzer::compute_escape_for_intrinsic(vmIntrinsics::ID iid) {
  1190   ArgumentMap arg;
  1191   arg.clear();
  1192   switch (iid) {
  1193   case vmIntrinsics::_getClass:
  1194     _return_local = false;
  1195     break;
  1196   case vmIntrinsics::_fillInStackTrace:
  1197     arg.set(0); // 'this'
  1198     set_returned(arg);
  1199     break;
  1200   case vmIntrinsics::_hashCode:
  1201     // initialized state is correct
  1202     break;
  1203   default:
  1204     assert(false, "unexpected intrinsic");
  1206   return true;
  1209 void BCEscapeAnalyzer::initialize() {
  1210   int i;
  1212   // clear escape information (method may have been deoptimized)
  1213   methodData()->clear_escape_info();
  1215   // initialize escape state of object parameters
  1216   ciSignature* sig = method()->signature();
  1217   int j = 0;
  1218   if (!method()->is_static()) {
  1219     _arg_local.set(0);
  1220     _arg_stack.set(0);
  1221     j++;
  1223   for (i = 0; i < sig->count(); i++) {
  1224     ciType* t = sig->type_at(i);
  1225     if (!t->is_primitive_type()) {
  1226       _arg_local.set(j);
  1227       _arg_stack.set(j);
  1229     j += t->size();
  1231   assert(j == _arg_size, "just checking");
  1233   // start with optimistic assumption
  1234   ciType *rt = _method->return_type();
  1235   if (rt->is_primitive_type()) {
  1236     _return_local = false;
  1237     _return_allocated = false;
  1238   } else {
  1239     _return_local = true;
  1240     _return_allocated = true;
  1242   _allocated_escapes = false;
  1243   _unknown_modified = false;
  1246 void BCEscapeAnalyzer::clear_escape_info() {
  1247   ciSignature* sig = method()->signature();
  1248   int arg_count = sig->count();
  1249   ArgumentMap var;
  1250   if (!method()->is_static()) {
  1251     arg_count++;  // allow for "this"
  1253   for (int i = 0; i < arg_count; i++) {
  1254     set_arg_modified(i, OFFSET_ANY, 4);
  1255     var.clear();
  1256     var.set(i);
  1257     set_modified(var, OFFSET_ANY, 4);
  1258     set_global_escape(var);
  1260   _arg_local.Clear();
  1261   _arg_stack.Clear();
  1262   _arg_returned.Clear();
  1263   _return_local = false;
  1264   _return_allocated = false;
  1265   _allocated_escapes = true;
  1266   _unknown_modified = true;
  1270 void BCEscapeAnalyzer::compute_escape_info() {
  1271   int i;
  1272   assert(!methodData()->has_escape_info(), "do not overwrite escape info");
  1274   vmIntrinsics::ID iid = known_intrinsic();
  1276   // check if method can be analyzed
  1277   if (iid ==  vmIntrinsics::_none && (method()->is_abstract() || method()->is_native() || !method()->holder()->is_initialized()
  1278       || _level > MaxBCEAEstimateLevel
  1279       || method()->code_size() > MaxBCEAEstimateSize)) {
  1280     if (BCEATraceLevel >= 1) {
  1281       tty->print("Skipping method because: ");
  1282       if (method()->is_abstract())
  1283         tty->print_cr("method is abstract.");
  1284       else if (method()->is_native())
  1285         tty->print_cr("method is native.");
  1286       else if (!method()->holder()->is_initialized())
  1287         tty->print_cr("class of method is not initialized.");
  1288       else if (_level > MaxBCEAEstimateLevel)
  1289         tty->print_cr("level (%d) exceeds MaxBCEAEstimateLevel (%d).",
  1290                       _level, MaxBCEAEstimateLevel);
  1291       else if (method()->code_size() > MaxBCEAEstimateSize)
  1292         tty->print_cr("code size (%d) exceeds MaxBCEAEstimateSize.",
  1293                       method()->code_size(), MaxBCEAEstimateSize);
  1294       else
  1295         ShouldNotReachHere();
  1297     clear_escape_info();
  1299     return;
  1302   if (BCEATraceLevel >= 1) {
  1303     tty->print("[EA] estimating escape information for");
  1304     if (iid != vmIntrinsics::_none)
  1305       tty->print(" intrinsic");
  1306     method()->print_short_name();
  1307     tty->print_cr(" (%d bytes)", method()->code_size());
  1310   bool success;
  1312   initialize();
  1314   // Do not scan method if it has no object parameters and
  1315   // does not returns an object (_return_allocated is set in initialize()).
  1316   if (_arg_local.Size() == 0 && !_return_allocated) {
  1317     // Clear all info since method's bytecode was not analysed and
  1318     // set pessimistic escape information.
  1319     clear_escape_info();
  1320     methodData()->set_eflag(MethodData::allocated_escapes);
  1321     methodData()->set_eflag(MethodData::unknown_modified);
  1322     methodData()->set_eflag(MethodData::estimated);
  1323     return;
  1326   if (iid != vmIntrinsics::_none)
  1327     success = compute_escape_for_intrinsic(iid);
  1328   else {
  1329     success = do_analysis();
  1332   // don't store interprocedural escape information if it introduces
  1333   // dependencies or if method data is empty
  1334   //
  1335   if (!has_dependencies() && !methodData()->is_empty()) {
  1336     for (i = 0; i < _arg_size; i++) {
  1337       if (_arg_local.test(i)) {
  1338         assert(_arg_stack.test(i), "inconsistent escape info");
  1339         methodData()->set_arg_local(i);
  1340         methodData()->set_arg_stack(i);
  1341       } else if (_arg_stack.test(i)) {
  1342         methodData()->set_arg_stack(i);
  1344       if (_arg_returned.test(i)) {
  1345         methodData()->set_arg_returned(i);
  1347       methodData()->set_arg_modified(i, _arg_modified[i]);
  1349     if (_return_local) {
  1350       methodData()->set_eflag(MethodData::return_local);
  1352     if (_return_allocated) {
  1353       methodData()->set_eflag(MethodData::return_allocated);
  1355     if (_allocated_escapes) {
  1356       methodData()->set_eflag(MethodData::allocated_escapes);
  1358     if (_unknown_modified) {
  1359       methodData()->set_eflag(MethodData::unknown_modified);
  1361     methodData()->set_eflag(MethodData::estimated);
  1365 void BCEscapeAnalyzer::read_escape_info() {
  1366   assert(methodData()->has_escape_info(), "no escape info available");
  1368   // read escape information from method descriptor
  1369   for (int i = 0; i < _arg_size; i++) {
  1370     if (methodData()->is_arg_local(i))
  1371       _arg_local.set(i);
  1372     if (methodData()->is_arg_stack(i))
  1373       _arg_stack.set(i);
  1374     if (methodData()->is_arg_returned(i))
  1375       _arg_returned.set(i);
  1376     _arg_modified[i] = methodData()->arg_modified(i);
  1378   _return_local = methodData()->eflag_set(MethodData::return_local);
  1379   _return_allocated = methodData()->eflag_set(MethodData::return_allocated);
  1380   _allocated_escapes = methodData()->eflag_set(MethodData::allocated_escapes);
  1381   _unknown_modified = methodData()->eflag_set(MethodData::unknown_modified);
  1385 #ifndef PRODUCT
  1386 void BCEscapeAnalyzer::dump() {
  1387   tty->print("[EA] estimated escape information for");
  1388   method()->print_short_name();
  1389   tty->print_cr(has_dependencies() ? " (not stored)" : "");
  1390   tty->print("     non-escaping args:      ");
  1391   _arg_local.print_on(tty);
  1392   tty->print("     stack-allocatable args: ");
  1393   _arg_stack.print_on(tty);
  1394   if (_return_local) {
  1395     tty->print("     returned args:          ");
  1396     _arg_returned.print_on(tty);
  1397   } else if (is_return_allocated()) {
  1398     tty->print_cr("     return allocated value");
  1399   } else {
  1400     tty->print_cr("     return non-local value");
  1402   tty->print("     modified args: ");
  1403   for (int i = 0; i < _arg_size; i++) {
  1404     if (_arg_modified[i] == 0)
  1405       tty->print("    0");
  1406     else
  1407       tty->print("    0x%x", _arg_modified[i]);
  1409   tty->cr();
  1410   tty->print("     flags: ");
  1411   if (_return_allocated)
  1412     tty->print(" return_allocated");
  1413   if (_allocated_escapes)
  1414     tty->print(" allocated_escapes");
  1415   if (_unknown_modified)
  1416     tty->print(" unknown_modified");
  1417   tty->cr();
  1419 #endif
  1421 BCEscapeAnalyzer::BCEscapeAnalyzer(ciMethod* method, BCEscapeAnalyzer* parent)
  1422     : _conservative(method == NULL || !EstimateArgEscape)
  1423     , _arena(CURRENT_ENV->arena())
  1424     , _method(method)
  1425     , _methodData(method ? method->method_data() : NULL)
  1426     , _arg_size(method ? method->arg_size() : 0)
  1427     , _arg_local(_arena)
  1428     , _arg_stack(_arena)
  1429     , _arg_returned(_arena)
  1430     , _dirty(_arena)
  1431     , _return_local(false)
  1432     , _return_allocated(false)
  1433     , _allocated_escapes(false)
  1434     , _unknown_modified(false)
  1435     , _dependencies(_arena, 4, 0, NULL)
  1436     , _parent(parent)
  1437     , _level(parent == NULL ? 0 : parent->level() + 1) {
  1438   if (!_conservative) {
  1439     _arg_local.Clear();
  1440     _arg_stack.Clear();
  1441     _arg_returned.Clear();
  1442     _dirty.Clear();
  1443     Arena* arena = CURRENT_ENV->arena();
  1444     _arg_modified = (uint *) arena->Amalloc(_arg_size * sizeof(uint));
  1445     Copy::zero_to_bytes(_arg_modified, _arg_size * sizeof(uint));
  1447     if (methodData() == NULL)
  1448       return;
  1449     bool printit = _method->should_print_assembly();
  1450     if (methodData()->has_escape_info()) {
  1451       TRACE_BCEA(2, tty->print_cr("[EA] Reading previous results for %s.%s",
  1452                                   method->holder()->name()->as_utf8(),
  1453                                   method->name()->as_utf8()));
  1454       read_escape_info();
  1455     } else {
  1456       TRACE_BCEA(2, tty->print_cr("[EA] computing results for %s.%s",
  1457                                   method->holder()->name()->as_utf8(),
  1458                                   method->name()->as_utf8()));
  1460       compute_escape_info();
  1461       methodData()->update_escape_info();
  1463 #ifndef PRODUCT
  1464     if (BCEATraceLevel >= 3) {
  1465       // dump escape information
  1466       dump();
  1468 #endif
  1472 void BCEscapeAnalyzer::copy_dependencies(Dependencies *deps) {
  1473   if (ciEnv::current()->jvmti_can_hotswap_or_post_breakpoint()) {
  1474     // Also record evol dependencies so redefinition of the
  1475     // callee will trigger recompilation.
  1476     deps->assert_evol_method(method());
  1478   for (int i = 0; i < _dependencies.length(); i+=2) {
  1479     ciKlass *k = _dependencies.at(i)->as_klass();
  1480     ciMethod *m = _dependencies.at(i+1)->as_method();
  1481     deps->assert_unique_concrete_method(k, m);

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