src/share/vm/ci/bcEscapeAnalyzer.cpp

Thu, 24 May 2018 18:41:44 +0800

author
aoqi
date
Thu, 24 May 2018 18:41:44 +0800
changeset 8856
ac27a9c85bea
parent 7994
04ff2f6cd0eb
child 9756
2be326848943
permissions
-rw-r--r--

Merge

     1 /*
     2  * Copyright (c) 2005, 2014, 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 arguments 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   int _stack_height;
    93   int _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   if (vars.contains_allocated()) {
   162     _allocated_escapes = true;
   163   }
   164 }
   166 void BCEscapeAnalyzer::set_global_escape(ArgumentMap vars, bool merge) {
   167   clear_bits(vars, _arg_local);
   168   clear_bits(vars, _arg_stack);
   169   if (vars.contains_allocated())
   170     _allocated_escapes = true;
   172   if (merge && !vars.is_empty()) {
   173     // Merge new state into already processed block.
   174     // New state is not taken into account and
   175     // it may invalidate set_returned() result.
   176     if (vars.contains_unknown() || vars.contains_allocated()) {
   177       _return_local = false;
   178     }
   179     if (vars.contains_unknown() || vars.contains_vars()) {
   180       _return_allocated = false;
   181     }
   182     if (_return_local && vars.contains_vars() && !returns_all(vars)) {
   183       // Return result should be invalidated if args in new
   184       // state are not recorded in return state.
   185       _return_local = false;
   186     }
   187   }
   188 }
   190 void BCEscapeAnalyzer::set_dirty(ArgumentMap vars) {
   191   clear_bits(vars, _dirty);
   192 }
   194 void BCEscapeAnalyzer::set_modified(ArgumentMap vars, int offs, int size) {
   196   for (int i = 0; i < _arg_size; i++) {
   197     if (vars.contains(i)) {
   198       set_arg_modified(i, offs, size);
   199     }
   200   }
   201   if (vars.contains_unknown())
   202     _unknown_modified = true;
   203 }
   205 bool BCEscapeAnalyzer::is_recursive_call(ciMethod* callee) {
   206   for (BCEscapeAnalyzer* scope = this; scope != NULL; scope = scope->_parent) {
   207     if (scope->method() == callee) {
   208       return true;
   209     }
   210   }
   211   return false;
   212 }
   214 bool BCEscapeAnalyzer::is_arg_modified(int arg, int offset, int size_in_bytes) {
   215   if (offset == OFFSET_ANY)
   216     return _arg_modified[arg] != 0;
   217   assert(arg >= 0 && arg < _arg_size, "must be an argument.");
   218   bool modified = false;
   219   int l = offset / HeapWordSize;
   220   int h = round_to(offset + size_in_bytes, HeapWordSize) / HeapWordSize;
   221   if (l > ARG_OFFSET_MAX)
   222     l = ARG_OFFSET_MAX;
   223   if (h > ARG_OFFSET_MAX+1)
   224     h = ARG_OFFSET_MAX + 1;
   225   for (int i = l; i < h; i++) {
   226     modified = modified || (_arg_modified[arg] & (1 << i)) != 0;
   227   }
   228   return modified;
   229 }
   231 void BCEscapeAnalyzer::set_arg_modified(int arg, int offset, int size_in_bytes) {
   232   if (offset == OFFSET_ANY) {
   233     _arg_modified[arg] =  (uint) -1;
   234     return;
   235   }
   236   assert(arg >= 0 && arg < _arg_size, "must be an argument.");
   237   int l = offset / HeapWordSize;
   238   int h = round_to(offset + size_in_bytes, HeapWordSize) / HeapWordSize;
   239   if (l > ARG_OFFSET_MAX)
   240     l = ARG_OFFSET_MAX;
   241   if (h > ARG_OFFSET_MAX+1)
   242     h = ARG_OFFSET_MAX + 1;
   243   for (int i = l; i < h; i++) {
   244     _arg_modified[arg] |= (1 << i);
   245   }
   246 }
   248 void BCEscapeAnalyzer::invoke(StateInfo &state, Bytecodes::Code code, ciMethod* target, ciKlass* holder) {
   249   int i;
   251   // retrieve information about the callee
   252   ciInstanceKlass* klass = target->holder();
   253   ciInstanceKlass* calling_klass = method()->holder();
   254   ciInstanceKlass* callee_holder = ciEnv::get_instance_klass_for_declared_method_holder(holder);
   255   ciInstanceKlass* actual_recv = callee_holder;
   257   // Some methods are obviously bindable without any type checks so
   258   // convert them directly to an invokespecial or invokestatic.
   259   if (target->is_loaded() && !target->is_abstract() && target->can_be_statically_bound()) {
   260     switch (code) {
   261     case Bytecodes::_invokevirtual:
   262       code = Bytecodes::_invokespecial;
   263       break;
   264     case Bytecodes::_invokehandle:
   265       code = target->is_static() ? Bytecodes::_invokestatic : Bytecodes::_invokespecial;
   266       break;
   267     }
   268   }
   270   // compute size of arguments
   271   int arg_size = target->invoke_arg_size(code);
   272   int arg_base = MAX2(state._stack_height - arg_size, 0);
   274   // direct recursive calls are skipped if they can be bound statically without introducing
   275   // dependencies and if parameters are passed at the same position as in the current method
   276   // other calls are skipped if there are no unescaped arguments passed to them
   277   bool directly_recursive = (method() == target) &&
   278                (code != Bytecodes::_invokevirtual || target->is_final_method() || state._stack[arg_base] .is_empty());
   280   // check if analysis of callee can safely be skipped
   281   bool skip_callee = true;
   282   for (i = state._stack_height - 1; i >= arg_base && skip_callee; i--) {
   283     ArgumentMap arg = state._stack[i];
   284     skip_callee = !is_argument(arg) || !is_arg_stack(arg) || (directly_recursive && arg.is_singleton(i - arg_base));
   285   }
   286   // For now we conservatively skip invokedynamic.
   287   if (code == Bytecodes::_invokedynamic) {
   288     skip_callee = true;
   289   }
   290   if (skip_callee) {
   291     TRACE_BCEA(3, tty->print_cr("[EA] skipping method %s::%s", holder->name()->as_utf8(), target->name()->as_utf8()));
   292     for (i = 0; i < arg_size; i++) {
   293       set_method_escape(state.raw_pop());
   294     }
   295     _unknown_modified = true;  // assume the worst since we don't analyze the called method
   296     return;
   297   }
   299   // determine actual method (use CHA if necessary)
   300   ciMethod* inline_target = NULL;
   301   if (target->is_loaded() && klass->is_loaded()
   302       && (klass->is_initialized() || klass->is_interface() && target->holder()->is_initialized())
   303       && target->is_loaded()) {
   304     if (code == Bytecodes::_invokestatic
   305         || code == Bytecodes::_invokespecial
   306         || code == Bytecodes::_invokevirtual && target->is_final_method()) {
   307       inline_target = target;
   308     } else {
   309       inline_target = target->find_monomorphic_target(calling_klass, callee_holder, actual_recv);
   310     }
   311   }
   313   if (inline_target != NULL && !is_recursive_call(inline_target)) {
   314     // analyze callee
   315     BCEscapeAnalyzer analyzer(inline_target, this);
   317     // adjust escape state of actual parameters
   318     bool must_record_dependencies = false;
   319     for (i = arg_size - 1; i >= 0; i--) {
   320       ArgumentMap arg = state.raw_pop();
   321       // Check if callee arg is a caller arg or an allocated object
   322       bool allocated = arg.contains_allocated();
   323       if (!(is_argument(arg) || allocated))
   324         continue;
   325       for (int j = 0; j < _arg_size; j++) {
   326         if (arg.contains(j)) {
   327           _arg_modified[j] |= analyzer._arg_modified[i];
   328         }
   329       }
   330       if (!(is_arg_stack(arg) || allocated)) {
   331         // arguments have already been recognized as escaping
   332       } else if (analyzer.is_arg_stack(i) && !analyzer.is_arg_returned(i)) {
   333         set_method_escape(arg);
   334         must_record_dependencies = true;
   335       } else {
   336         set_global_escape(arg);
   337       }
   338     }
   339     _unknown_modified = _unknown_modified || analyzer.has_non_arg_side_affects();
   341     // record dependencies if at least one parameter retained stack-allocatable
   342     if (must_record_dependencies) {
   343       if (code == Bytecodes::_invokeinterface || code == Bytecodes::_invokevirtual && !target->is_final_method()) {
   344         _dependencies.append(actual_recv);
   345         _dependencies.append(inline_target);
   346       }
   347       _dependencies.appendAll(analyzer.dependencies());
   348     }
   349   } else {
   350     TRACE_BCEA(1, tty->print_cr("[EA] virtual method %s is not monomorphic.",
   351                                 target->name()->as_utf8()));
   352     // conservatively mark all actual parameters as escaping globally
   353     for (i = 0; i < arg_size; i++) {
   354       ArgumentMap arg = state.raw_pop();
   355       if (!is_argument(arg))
   356         continue;
   357       set_modified(arg, OFFSET_ANY, type2size[T_INT]*HeapWordSize);
   358       set_global_escape(arg);
   359     }
   360     _unknown_modified = true;  // assume the worst since we don't know the called method
   361   }
   362 }
   364 bool BCEscapeAnalyzer::contains(uint arg_set1, uint arg_set2) {
   365   return ((~arg_set1) | arg_set2) == 0;
   366 }
   369 void BCEscapeAnalyzer::iterate_one_block(ciBlock *blk, StateInfo &state, GrowableArray<ciBlock *> &successors) {
   371   blk->set_processed();
   372   ciBytecodeStream s(method());
   373   int limit_bci = blk->limit_bci();
   374   bool fall_through = false;
   375   ArgumentMap allocated_obj;
   376   allocated_obj.add_allocated();
   377   ArgumentMap unknown_obj;
   378   unknown_obj.add_unknown();
   379   ArgumentMap empty_map;
   381   s.reset_to_bci(blk->start_bci());
   382   while (s.next() != ciBytecodeStream::EOBC() && s.cur_bci() < limit_bci) {
   383     fall_through = true;
   384     switch (s.cur_bc()) {
   385       case Bytecodes::_nop:
   386         break;
   387       case Bytecodes::_aconst_null:
   388         state.apush(unknown_obj);
   389         break;
   390       case Bytecodes::_iconst_m1:
   391       case Bytecodes::_iconst_0:
   392       case Bytecodes::_iconst_1:
   393       case Bytecodes::_iconst_2:
   394       case Bytecodes::_iconst_3:
   395       case Bytecodes::_iconst_4:
   396       case Bytecodes::_iconst_5:
   397       case Bytecodes::_fconst_0:
   398       case Bytecodes::_fconst_1:
   399       case Bytecodes::_fconst_2:
   400       case Bytecodes::_bipush:
   401       case Bytecodes::_sipush:
   402         state.spush();
   403         break;
   404       case Bytecodes::_lconst_0:
   405       case Bytecodes::_lconst_1:
   406       case Bytecodes::_dconst_0:
   407       case Bytecodes::_dconst_1:
   408         state.lpush();
   409         break;
   410       case Bytecodes::_ldc:
   411       case Bytecodes::_ldc_w:
   412       case Bytecodes::_ldc2_w:
   413       {
   414         // Avoid calling get_constant() which will try to allocate
   415         // unloaded constant. We need only constant's type.
   416         int index = s.get_constant_pool_index();
   417         constantTag tag = s.get_constant_pool_tag(index);
   418         if (tag.is_long() || tag.is_double()) {
   419           // Only longs and doubles use 2 stack slots.
   420           state.lpush();
   421         } else if (tag.basic_type() == T_OBJECT) {
   422           state.apush(unknown_obj);
   423         } else {
   424           state.spush();
   425         }
   426         break;
   427       }
   428       case Bytecodes::_aload:
   429         state.apush(state._vars[s.get_index()]);
   430         break;
   431       case Bytecodes::_iload:
   432       case Bytecodes::_fload:
   433       case Bytecodes::_iload_0:
   434       case Bytecodes::_iload_1:
   435       case Bytecodes::_iload_2:
   436       case Bytecodes::_iload_3:
   437       case Bytecodes::_fload_0:
   438       case Bytecodes::_fload_1:
   439       case Bytecodes::_fload_2:
   440       case Bytecodes::_fload_3:
   441         state.spush();
   442         break;
   443       case Bytecodes::_lload:
   444       case Bytecodes::_dload:
   445       case Bytecodes::_lload_0:
   446       case Bytecodes::_lload_1:
   447       case Bytecodes::_lload_2:
   448       case Bytecodes::_lload_3:
   449       case Bytecodes::_dload_0:
   450       case Bytecodes::_dload_1:
   451       case Bytecodes::_dload_2:
   452       case Bytecodes::_dload_3:
   453         state.lpush();
   454         break;
   455       case Bytecodes::_aload_0:
   456         state.apush(state._vars[0]);
   457         break;
   458       case Bytecodes::_aload_1:
   459         state.apush(state._vars[1]);
   460         break;
   461       case Bytecodes::_aload_2:
   462         state.apush(state._vars[2]);
   463         break;
   464       case Bytecodes::_aload_3:
   465         state.apush(state._vars[3]);
   466         break;
   467       case Bytecodes::_iaload:
   468       case Bytecodes::_faload:
   469       case Bytecodes::_baload:
   470       case Bytecodes::_caload:
   471       case Bytecodes::_saload:
   472         state.spop();
   473         set_method_escape(state.apop());
   474         state.spush();
   475         break;
   476       case Bytecodes::_laload:
   477       case Bytecodes::_daload:
   478         state.spop();
   479         set_method_escape(state.apop());
   480         state.lpush();
   481         break;
   482       case Bytecodes::_aaload:
   483         { state.spop();
   484           ArgumentMap array = state.apop();
   485           set_method_escape(array);
   486           state.apush(unknown_obj);
   487           set_dirty(array);
   488         }
   489         break;
   490       case Bytecodes::_istore:
   491       case Bytecodes::_fstore:
   492       case Bytecodes::_istore_0:
   493       case Bytecodes::_istore_1:
   494       case Bytecodes::_istore_2:
   495       case Bytecodes::_istore_3:
   496       case Bytecodes::_fstore_0:
   497       case Bytecodes::_fstore_1:
   498       case Bytecodes::_fstore_2:
   499       case Bytecodes::_fstore_3:
   500         state.spop();
   501         break;
   502       case Bytecodes::_lstore:
   503       case Bytecodes::_dstore:
   504       case Bytecodes::_lstore_0:
   505       case Bytecodes::_lstore_1:
   506       case Bytecodes::_lstore_2:
   507       case Bytecodes::_lstore_3:
   508       case Bytecodes::_dstore_0:
   509       case Bytecodes::_dstore_1:
   510       case Bytecodes::_dstore_2:
   511       case Bytecodes::_dstore_3:
   512         state.lpop();
   513         break;
   514       case Bytecodes::_astore:
   515         state._vars[s.get_index()] = state.apop();
   516         break;
   517       case Bytecodes::_astore_0:
   518         state._vars[0] = state.apop();
   519         break;
   520       case Bytecodes::_astore_1:
   521         state._vars[1] = state.apop();
   522         break;
   523       case Bytecodes::_astore_2:
   524         state._vars[2] = state.apop();
   525         break;
   526       case Bytecodes::_astore_3:
   527         state._vars[3] = state.apop();
   528         break;
   529       case Bytecodes::_iastore:
   530       case Bytecodes::_fastore:
   531       case Bytecodes::_bastore:
   532       case Bytecodes::_castore:
   533       case Bytecodes::_sastore:
   534       {
   535         state.spop();
   536         state.spop();
   537         ArgumentMap arr = state.apop();
   538         set_method_escape(arr);
   539         set_modified(arr, OFFSET_ANY, type2size[T_INT]*HeapWordSize);
   540         break;
   541       }
   542       case Bytecodes::_lastore:
   543       case Bytecodes::_dastore:
   544       {
   545         state.lpop();
   546         state.spop();
   547         ArgumentMap arr = state.apop();
   548         set_method_escape(arr);
   549         set_modified(arr, OFFSET_ANY, type2size[T_LONG]*HeapWordSize);
   550         break;
   551       }
   552       case Bytecodes::_aastore:
   553       {
   554         set_global_escape(state.apop());
   555         state.spop();
   556         ArgumentMap arr = state.apop();
   557         set_modified(arr, OFFSET_ANY, type2size[T_OBJECT]*HeapWordSize);
   558         break;
   559       }
   560       case Bytecodes::_pop:
   561         state.raw_pop();
   562         break;
   563       case Bytecodes::_pop2:
   564         state.raw_pop();
   565         state.raw_pop();
   566         break;
   567       case Bytecodes::_dup:
   568         { ArgumentMap w1 = state.raw_pop();
   569           state.raw_push(w1);
   570           state.raw_push(w1);
   571         }
   572         break;
   573       case Bytecodes::_dup_x1:
   574         { ArgumentMap w1 = state.raw_pop();
   575           ArgumentMap w2 = state.raw_pop();
   576           state.raw_push(w1);
   577           state.raw_push(w2);
   578           state.raw_push(w1);
   579         }
   580         break;
   581       case Bytecodes::_dup_x2:
   582         { ArgumentMap w1 = state.raw_pop();
   583           ArgumentMap w2 = state.raw_pop();
   584           ArgumentMap w3 = state.raw_pop();
   585           state.raw_push(w1);
   586           state.raw_push(w3);
   587           state.raw_push(w2);
   588           state.raw_push(w1);
   589         }
   590         break;
   591       case Bytecodes::_dup2:
   592         { ArgumentMap w1 = state.raw_pop();
   593           ArgumentMap w2 = state.raw_pop();
   594           state.raw_push(w2);
   595           state.raw_push(w1);
   596           state.raw_push(w2);
   597           state.raw_push(w1);
   598         }
   599         break;
   600       case Bytecodes::_dup2_x1:
   601         { ArgumentMap w1 = state.raw_pop();
   602           ArgumentMap w2 = state.raw_pop();
   603           ArgumentMap w3 = state.raw_pop();
   604           state.raw_push(w2);
   605           state.raw_push(w1);
   606           state.raw_push(w3);
   607           state.raw_push(w2);
   608           state.raw_push(w1);
   609         }
   610         break;
   611       case Bytecodes::_dup2_x2:
   612         { ArgumentMap w1 = state.raw_pop();
   613           ArgumentMap w2 = state.raw_pop();
   614           ArgumentMap w3 = state.raw_pop();
   615           ArgumentMap w4 = state.raw_pop();
   616           state.raw_push(w2);
   617           state.raw_push(w1);
   618           state.raw_push(w4);
   619           state.raw_push(w3);
   620           state.raw_push(w2);
   621           state.raw_push(w1);
   622         }
   623         break;
   624       case Bytecodes::_swap:
   625         { ArgumentMap w1 = state.raw_pop();
   626           ArgumentMap w2 = state.raw_pop();
   627           state.raw_push(w1);
   628           state.raw_push(w2);
   629         }
   630         break;
   631       case Bytecodes::_iadd:
   632       case Bytecodes::_fadd:
   633       case Bytecodes::_isub:
   634       case Bytecodes::_fsub:
   635       case Bytecodes::_imul:
   636       case Bytecodes::_fmul:
   637       case Bytecodes::_idiv:
   638       case Bytecodes::_fdiv:
   639       case Bytecodes::_irem:
   640       case Bytecodes::_frem:
   641       case Bytecodes::_iand:
   642       case Bytecodes::_ior:
   643       case Bytecodes::_ixor:
   644         state.spop();
   645         state.spop();
   646         state.spush();
   647         break;
   648       case Bytecodes::_ladd:
   649       case Bytecodes::_dadd:
   650       case Bytecodes::_lsub:
   651       case Bytecodes::_dsub:
   652       case Bytecodes::_lmul:
   653       case Bytecodes::_dmul:
   654       case Bytecodes::_ldiv:
   655       case Bytecodes::_ddiv:
   656       case Bytecodes::_lrem:
   657       case Bytecodes::_drem:
   658       case Bytecodes::_land:
   659       case Bytecodes::_lor:
   660       case Bytecodes::_lxor:
   661         state.lpop();
   662         state.lpop();
   663         state.lpush();
   664         break;
   665       case Bytecodes::_ishl:
   666       case Bytecodes::_ishr:
   667       case Bytecodes::_iushr:
   668         state.spop();
   669         state.spop();
   670         state.spush();
   671         break;
   672       case Bytecodes::_lshl:
   673       case Bytecodes::_lshr:
   674       case Bytecodes::_lushr:
   675         state.spop();
   676         state.lpop();
   677         state.lpush();
   678         break;
   679       case Bytecodes::_ineg:
   680       case Bytecodes::_fneg:
   681         state.spop();
   682         state.spush();
   683         break;
   684       case Bytecodes::_lneg:
   685       case Bytecodes::_dneg:
   686         state.lpop();
   687         state.lpush();
   688         break;
   689       case Bytecodes::_iinc:
   690         break;
   691       case Bytecodes::_i2l:
   692       case Bytecodes::_i2d:
   693       case Bytecodes::_f2l:
   694       case Bytecodes::_f2d:
   695         state.spop();
   696         state.lpush();
   697         break;
   698       case Bytecodes::_i2f:
   699       case Bytecodes::_f2i:
   700         state.spop();
   701         state.spush();
   702         break;
   703       case Bytecodes::_l2i:
   704       case Bytecodes::_l2f:
   705       case Bytecodes::_d2i:
   706       case Bytecodes::_d2f:
   707         state.lpop();
   708         state.spush();
   709         break;
   710       case Bytecodes::_l2d:
   711       case Bytecodes::_d2l:
   712         state.lpop();
   713         state.lpush();
   714         break;
   715       case Bytecodes::_i2b:
   716       case Bytecodes::_i2c:
   717       case Bytecodes::_i2s:
   718         state.spop();
   719         state.spush();
   720         break;
   721       case Bytecodes::_lcmp:
   722       case Bytecodes::_dcmpl:
   723       case Bytecodes::_dcmpg:
   724         state.lpop();
   725         state.lpop();
   726         state.spush();
   727         break;
   728       case Bytecodes::_fcmpl:
   729       case Bytecodes::_fcmpg:
   730         state.spop();
   731         state.spop();
   732         state.spush();
   733         break;
   734       case Bytecodes::_ifeq:
   735       case Bytecodes::_ifne:
   736       case Bytecodes::_iflt:
   737       case Bytecodes::_ifge:
   738       case Bytecodes::_ifgt:
   739       case Bytecodes::_ifle:
   740       {
   741         state.spop();
   742         int dest_bci = s.get_dest();
   743         assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
   744         assert(s.next_bci() == limit_bci, "branch must end block");
   745         successors.push(_methodBlocks->block_containing(dest_bci));
   746         break;
   747       }
   748       case Bytecodes::_if_icmpeq:
   749       case Bytecodes::_if_icmpne:
   750       case Bytecodes::_if_icmplt:
   751       case Bytecodes::_if_icmpge:
   752       case Bytecodes::_if_icmpgt:
   753       case Bytecodes::_if_icmple:
   754       {
   755         state.spop();
   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_acmpeq:
   764       case Bytecodes::_if_acmpne:
   765       {
   766         set_method_escape(state.apop());
   767         set_method_escape(state.apop());
   768         int dest_bci = s.get_dest();
   769         assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
   770         assert(s.next_bci() == limit_bci, "branch must end block");
   771         successors.push(_methodBlocks->block_containing(dest_bci));
   772         break;
   773       }
   774       case Bytecodes::_goto:
   775       {
   776         int dest_bci = s.get_dest();
   777         assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
   778         assert(s.next_bci() == limit_bci, "branch must end block");
   779         successors.push(_methodBlocks->block_containing(dest_bci));
   780         fall_through = false;
   781         break;
   782       }
   783       case Bytecodes::_jsr:
   784       {
   785         int dest_bci = s.get_dest();
   786         assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
   787         assert(s.next_bci() == limit_bci, "branch must end block");
   788         state.apush(empty_map);
   789         successors.push(_methodBlocks->block_containing(dest_bci));
   790         fall_through = false;
   791         break;
   792       }
   793       case Bytecodes::_ret:
   794         // we don't track  the destination of a "ret" instruction
   795         assert(s.next_bci() == limit_bci, "branch must end block");
   796         fall_through = false;
   797         break;
   798       case Bytecodes::_return:
   799         assert(s.next_bci() == limit_bci, "return must end block");
   800         fall_through = false;
   801         break;
   802       case Bytecodes::_tableswitch:
   803         {
   804           state.spop();
   805           Bytecode_tableswitch sw(&s);
   806           int len = sw.length();
   807           int dest_bci;
   808           for (int i = 0; i < len; i++) {
   809             dest_bci = s.cur_bci() + sw.dest_offset_at(i);
   810             assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
   811             successors.push(_methodBlocks->block_containing(dest_bci));
   812           }
   813           dest_bci = s.cur_bci() + sw.default_offset();
   814           assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
   815           successors.push(_methodBlocks->block_containing(dest_bci));
   816           assert(s.next_bci() == limit_bci, "branch must end block");
   817           fall_through = false;
   818           break;
   819         }
   820       case Bytecodes::_lookupswitch:
   821         {
   822           state.spop();
   823           Bytecode_lookupswitch sw(&s);
   824           int len = sw.number_of_pairs();
   825           int dest_bci;
   826           for (int i = 0; i < len; i++) {
   827             dest_bci = s.cur_bci() + sw.pair_at(i).offset();
   828             assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
   829             successors.push(_methodBlocks->block_containing(dest_bci));
   830           }
   831           dest_bci = s.cur_bci() + sw.default_offset();
   832           assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
   833           successors.push(_methodBlocks->block_containing(dest_bci));
   834           fall_through = false;
   835           break;
   836         }
   837       case Bytecodes::_ireturn:
   838       case Bytecodes::_freturn:
   839         state.spop();
   840         fall_through = false;
   841         break;
   842       case Bytecodes::_lreturn:
   843       case Bytecodes::_dreturn:
   844         state.lpop();
   845         fall_through = false;
   846         break;
   847       case Bytecodes::_areturn:
   848         set_returned(state.apop());
   849         fall_through = false;
   850         break;
   851       case Bytecodes::_getstatic:
   852       case Bytecodes::_getfield:
   853         { bool ignored_will_link;
   854           ciField* field = s.get_field(ignored_will_link);
   855           BasicType field_type = field->type()->basic_type();
   856           if (s.cur_bc() != Bytecodes::_getstatic) {
   857             set_method_escape(state.apop());
   858           }
   859           if (field_type == T_OBJECT || field_type == T_ARRAY) {
   860             state.apush(unknown_obj);
   861           } else if (type2size[field_type] == 1) {
   862             state.spush();
   863           } else {
   864             state.lpush();
   865           }
   866         }
   867         break;
   868       case Bytecodes::_putstatic:
   869       case Bytecodes::_putfield:
   870         { bool will_link;
   871           ciField* field = s.get_field(will_link);
   872           BasicType field_type = field->type()->basic_type();
   873           if (field_type == T_OBJECT || field_type == T_ARRAY) {
   874             set_global_escape(state.apop());
   875           } else if (type2size[field_type] == 1) {
   876             state.spop();
   877           } else {
   878             state.lpop();
   879           }
   880           if (s.cur_bc() != Bytecodes::_putstatic) {
   881             ArgumentMap p = state.apop();
   882             set_method_escape(p);
   883             set_modified(p, will_link ? field->offset() : OFFSET_ANY, type2size[field_type]*HeapWordSize);
   884           }
   885         }
   886         break;
   887       case Bytecodes::_invokevirtual:
   888       case Bytecodes::_invokespecial:
   889       case Bytecodes::_invokestatic:
   890       case Bytecodes::_invokedynamic:
   891       case Bytecodes::_invokeinterface:
   892         { bool ignored_will_link;
   893           ciSignature* declared_signature = NULL;
   894           ciMethod* target = s.get_method(ignored_will_link, &declared_signature);
   895           ciKlass*  holder = s.get_declared_method_holder();
   896           assert(declared_signature != NULL, "cannot be null");
   897           // Push appendix argument, if one.
   898           if (s.has_appendix()) {
   899             state.apush(unknown_obj);
   900           }
   901           // Pass in raw bytecode because we need to see invokehandle instructions.
   902           invoke(state, s.cur_bc_raw(), target, holder);
   903           // We are using the return type of the declared signature here because
   904           // it might be a more concrete type than the one from the target (for
   905           // e.g. invokedynamic and invokehandle).
   906           ciType* return_type = declared_signature->return_type();
   907           if (!return_type->is_primitive_type()) {
   908             state.apush(unknown_obj);
   909           } else if (return_type->is_one_word()) {
   910             state.spush();
   911           } else if (return_type->is_two_word()) {
   912             state.lpush();
   913           }
   914         }
   915         break;
   916       case Bytecodes::_new:
   917         state.apush(allocated_obj);
   918         break;
   919       case Bytecodes::_newarray:
   920       case Bytecodes::_anewarray:
   921         state.spop();
   922         state.apush(allocated_obj);
   923         break;
   924       case Bytecodes::_multianewarray:
   925         { int i = s.cur_bcp()[3];
   926           while (i-- > 0) state.spop();
   927           state.apush(allocated_obj);
   928         }
   929         break;
   930       case Bytecodes::_arraylength:
   931         set_method_escape(state.apop());
   932         state.spush();
   933         break;
   934       case Bytecodes::_athrow:
   935         set_global_escape(state.apop());
   936         fall_through = false;
   937         break;
   938       case Bytecodes::_checkcast:
   939         { ArgumentMap obj = state.apop();
   940           set_method_escape(obj);
   941           state.apush(obj);
   942         }
   943         break;
   944       case Bytecodes::_instanceof:
   945         set_method_escape(state.apop());
   946         state.spush();
   947         break;
   948       case Bytecodes::_monitorenter:
   949       case Bytecodes::_monitorexit:
   950         state.apop();
   951         break;
   952       case Bytecodes::_wide:
   953         ShouldNotReachHere();
   954         break;
   955       case Bytecodes::_ifnull:
   956       case Bytecodes::_ifnonnull:
   957       {
   958         set_method_escape(state.apop());
   959         int dest_bci = s.get_dest();
   960         assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
   961         assert(s.next_bci() == limit_bci, "branch must end block");
   962         successors.push(_methodBlocks->block_containing(dest_bci));
   963         break;
   964       }
   965       case Bytecodes::_goto_w:
   966       {
   967         int dest_bci = s.get_far_dest();
   968         assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
   969         assert(s.next_bci() == limit_bci, "branch must end block");
   970         successors.push(_methodBlocks->block_containing(dest_bci));
   971         fall_through = false;
   972         break;
   973       }
   974       case Bytecodes::_jsr_w:
   975       {
   976         int dest_bci = s.get_far_dest();
   977         assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
   978         assert(s.next_bci() == limit_bci, "branch must end block");
   979         state.apush(empty_map);
   980         successors.push(_methodBlocks->block_containing(dest_bci));
   981         fall_through = false;
   982         break;
   983       }
   984       case Bytecodes::_breakpoint:
   985         break;
   986       default:
   987         ShouldNotReachHere();
   988         break;
   989     }
   991   }
   992   if (fall_through) {
   993     int fall_through_bci = s.cur_bci();
   994     if (fall_through_bci < _method->code_size()) {
   995       assert(_methodBlocks->is_block_start(fall_through_bci), "must fall through to block start.");
   996       successors.push(_methodBlocks->block_containing(fall_through_bci));
   997     }
   998   }
   999 }
  1001 void BCEscapeAnalyzer::merge_block_states(StateInfo *blockstates, ciBlock *dest, StateInfo *s_state) {
  1002   StateInfo *d_state = blockstates + dest->index();
  1003   int nlocals = _method->max_locals();
  1005   // exceptions may cause transfer of control to handlers in the middle of a
  1006   // block, so we don't merge the incoming state of exception handlers
  1007   if (dest->is_handler())
  1008     return;
  1009   if (!d_state->_initialized ) {
  1010     // destination not initialized, just copy
  1011     for (int i = 0; i < nlocals; i++) {
  1012       d_state->_vars[i] = s_state->_vars[i];
  1014     for (int i = 0; i < s_state->_stack_height; i++) {
  1015       d_state->_stack[i] = s_state->_stack[i];
  1017     d_state->_stack_height = s_state->_stack_height;
  1018     d_state->_max_stack = s_state->_max_stack;
  1019     d_state->_initialized = true;
  1020   } else if (!dest->processed()) {
  1021     // we have not yet walked the bytecodes of dest, we can merge
  1022     // the states
  1023     assert(d_state->_stack_height == s_state->_stack_height, "computed stack heights must match");
  1024     for (int i = 0; i < nlocals; i++) {
  1025       d_state->_vars[i].set_union(s_state->_vars[i]);
  1027     for (int i = 0; i < s_state->_stack_height; i++) {
  1028       d_state->_stack[i].set_union(s_state->_stack[i]);
  1030   } else {
  1031     // the bytecodes of dest have already been processed, mark any
  1032     // arguments in the source state which are not in the dest state
  1033     // as global escape.
  1034     // Future refinement:  we only need to mark these variable to the
  1035     // maximum escape of any variables in dest state
  1036     assert(d_state->_stack_height == s_state->_stack_height, "computed stack heights must match");
  1037     ArgumentMap extra_vars;
  1038     for (int i = 0; i < nlocals; i++) {
  1039       ArgumentMap t;
  1040       t = s_state->_vars[i];
  1041       t.set_difference(d_state->_vars[i]);
  1042       extra_vars.set_union(t);
  1044     for (int i = 0; i < s_state->_stack_height; i++) {
  1045       ArgumentMap t;
  1046       //extra_vars |= !d_state->_vars[i] & s_state->_vars[i];
  1047       t.clear();
  1048       t = s_state->_stack[i];
  1049       t.set_difference(d_state->_stack[i]);
  1050       extra_vars.set_union(t);
  1052     set_global_escape(extra_vars, true);
  1056 void BCEscapeAnalyzer::iterate_blocks(Arena *arena) {
  1057   int numblocks = _methodBlocks->num_blocks();
  1058   int stkSize   = _method->max_stack();
  1059   int numLocals = _method->max_locals();
  1060   StateInfo state;
  1062   int datacount = (numblocks + 1) * (stkSize + numLocals);
  1063   int datasize = datacount * sizeof(ArgumentMap);
  1064   StateInfo *blockstates = (StateInfo *) arena->Amalloc(numblocks * sizeof(StateInfo));
  1065   ArgumentMap *statedata  = (ArgumentMap *) arena->Amalloc(datasize);
  1066   for (int i = 0; i < datacount; i++) ::new ((void*)&statedata[i]) ArgumentMap();
  1067   ArgumentMap *dp = statedata;
  1068   state._vars = dp;
  1069   dp += numLocals;
  1070   state._stack = dp;
  1071   dp += stkSize;
  1072   state._initialized = false;
  1073   state._max_stack = stkSize;
  1074   for (int i = 0; i < numblocks; i++) {
  1075     blockstates[i]._vars = dp;
  1076     dp += numLocals;
  1077     blockstates[i]._stack = dp;
  1078     dp += stkSize;
  1079     blockstates[i]._initialized = false;
  1080     blockstates[i]._stack_height = 0;
  1081     blockstates[i]._max_stack  = stkSize;
  1083   GrowableArray<ciBlock *> worklist(arena, numblocks / 4, 0, NULL);
  1084   GrowableArray<ciBlock *> successors(arena, 4, 0, NULL);
  1086   _methodBlocks->clear_processed();
  1088   // initialize block 0 state from method signature
  1089   ArgumentMap allVars;   // all oop arguments to method
  1090   ciSignature* sig = method()->signature();
  1091   int j = 0;
  1092   ciBlock* first_blk = _methodBlocks->block_containing(0);
  1093   int fb_i = first_blk->index();
  1094   if (!method()->is_static()) {
  1095     // record information for "this"
  1096     blockstates[fb_i]._vars[j].set(j);
  1097     allVars.add(j);
  1098     j++;
  1100   for (int i = 0; i < sig->count(); i++) {
  1101     ciType* t = sig->type_at(i);
  1102     if (!t->is_primitive_type()) {
  1103       blockstates[fb_i]._vars[j].set(j);
  1104       allVars.add(j);
  1106     j += t->size();
  1108   blockstates[fb_i]._initialized = true;
  1109   assert(j == _arg_size, "just checking");
  1111   ArgumentMap unknown_map;
  1112   unknown_map.add_unknown();
  1114   worklist.push(first_blk);
  1115   while(worklist.length() > 0) {
  1116     ciBlock *blk = worklist.pop();
  1117     StateInfo *blkState = blockstates + blk->index();
  1118     if (blk->is_handler() || blk->is_ret_target()) {
  1119       // for an exception handler or a target of a ret instruction, we assume the worst case,
  1120       // that any variable could contain any argument
  1121       for (int i = 0; i < numLocals; i++) {
  1122         state._vars[i] = allVars;
  1124       if (blk->is_handler()) {
  1125         state._stack_height = 1;
  1126       } else {
  1127         state._stack_height = blkState->_stack_height;
  1129       for (int i = 0; i < state._stack_height; i++) {
  1130 // ??? should this be unknown_map ???
  1131         state._stack[i] = allVars;
  1133     } else {
  1134       for (int i = 0; i < numLocals; i++) {
  1135         state._vars[i] = blkState->_vars[i];
  1137       for (int i = 0; i < blkState->_stack_height; i++) {
  1138         state._stack[i] = blkState->_stack[i];
  1140       state._stack_height = blkState->_stack_height;
  1142     iterate_one_block(blk, state, successors);
  1143     // if this block has any exception handlers, push them
  1144     // onto successor list
  1145     if (blk->has_handler()) {
  1146       DEBUG_ONLY(int handler_count = 0;)
  1147       int blk_start = blk->start_bci();
  1148       int blk_end = blk->limit_bci();
  1149       for (int i = 0; i < numblocks; i++) {
  1150         ciBlock *b = _methodBlocks->block(i);
  1151         if (b->is_handler()) {
  1152           int ex_start = b->ex_start_bci();
  1153           int ex_end = b->ex_limit_bci();
  1154           if ((ex_start >= blk_start && ex_start < blk_end) ||
  1155               (ex_end > blk_start && ex_end <= blk_end)) {
  1156             successors.push(b);
  1158           DEBUG_ONLY(handler_count++;)
  1161       assert(handler_count > 0, "must find at least one handler");
  1163     // merge computed variable state with successors
  1164     while(successors.length() > 0) {
  1165       ciBlock *succ = successors.pop();
  1166       merge_block_states(blockstates, succ, &state);
  1167       if (!succ->processed())
  1168         worklist.push(succ);
  1173 bool BCEscapeAnalyzer::do_analysis() {
  1174   Arena* arena = CURRENT_ENV->arena();
  1175   // identify basic blocks
  1176   _methodBlocks = _method->get_method_blocks();
  1178   iterate_blocks(arena);
  1179   // TEMPORARY
  1180   return true;
  1183 vmIntrinsics::ID BCEscapeAnalyzer::known_intrinsic() {
  1184   vmIntrinsics::ID iid = method()->intrinsic_id();
  1186   if (iid == vmIntrinsics::_getClass ||
  1187       iid ==  vmIntrinsics::_fillInStackTrace ||
  1188       iid == vmIntrinsics::_hashCode)
  1189     return iid;
  1190   else
  1191     return vmIntrinsics::_none;
  1194 bool BCEscapeAnalyzer::compute_escape_for_intrinsic(vmIntrinsics::ID iid) {
  1195   ArgumentMap arg;
  1196   arg.clear();
  1197   switch (iid) {
  1198   case vmIntrinsics::_getClass:
  1199     _return_local = false;
  1200     break;
  1201   case vmIntrinsics::_fillInStackTrace:
  1202     arg.set(0); // 'this'
  1203     set_returned(arg);
  1204     break;
  1205   case vmIntrinsics::_hashCode:
  1206     // initialized state is correct
  1207     break;
  1208   default:
  1209     assert(false, "unexpected intrinsic");
  1211   return true;
  1214 void BCEscapeAnalyzer::initialize() {
  1215   int i;
  1217   // clear escape information (method may have been deoptimized)
  1218   methodData()->clear_escape_info();
  1220   // initialize escape state of object parameters
  1221   ciSignature* sig = method()->signature();
  1222   int j = 0;
  1223   if (!method()->is_static()) {
  1224     _arg_local.set(0);
  1225     _arg_stack.set(0);
  1226     j++;
  1228   for (i = 0; i < sig->count(); i++) {
  1229     ciType* t = sig->type_at(i);
  1230     if (!t->is_primitive_type()) {
  1231       _arg_local.set(j);
  1232       _arg_stack.set(j);
  1234     j += t->size();
  1236   assert(j == _arg_size, "just checking");
  1238   // start with optimistic assumption
  1239   ciType *rt = _method->return_type();
  1240   if (rt->is_primitive_type()) {
  1241     _return_local = false;
  1242     _return_allocated = false;
  1243   } else {
  1244     _return_local = true;
  1245     _return_allocated = true;
  1247   _allocated_escapes = false;
  1248   _unknown_modified = false;
  1251 void BCEscapeAnalyzer::clear_escape_info() {
  1252   ciSignature* sig = method()->signature();
  1253   int arg_count = sig->count();
  1254   ArgumentMap var;
  1255   if (!method()->is_static()) {
  1256     arg_count++;  // allow for "this"
  1258   for (int i = 0; i < arg_count; i++) {
  1259     set_arg_modified(i, OFFSET_ANY, 4);
  1260     var.clear();
  1261     var.set(i);
  1262     set_modified(var, OFFSET_ANY, 4);
  1263     set_global_escape(var);
  1265   _arg_local.Clear();
  1266   _arg_stack.Clear();
  1267   _arg_returned.Clear();
  1268   _return_local = false;
  1269   _return_allocated = false;
  1270   _allocated_escapes = true;
  1271   _unknown_modified = true;
  1275 void BCEscapeAnalyzer::compute_escape_info() {
  1276   int i;
  1277   assert(!methodData()->has_escape_info(), "do not overwrite escape info");
  1279   vmIntrinsics::ID iid = known_intrinsic();
  1281   // check if method can be analyzed
  1282   if (iid ==  vmIntrinsics::_none && (method()->is_abstract() || method()->is_native() || !method()->holder()->is_initialized()
  1283       || _level > MaxBCEAEstimateLevel
  1284       || method()->code_size() > MaxBCEAEstimateSize)) {
  1285     if (BCEATraceLevel >= 1) {
  1286       tty->print("Skipping method because: ");
  1287       if (method()->is_abstract())
  1288         tty->print_cr("method is abstract.");
  1289       else if (method()->is_native())
  1290         tty->print_cr("method is native.");
  1291       else if (!method()->holder()->is_initialized())
  1292         tty->print_cr("class of method is not initialized.");
  1293       else if (_level > MaxBCEAEstimateLevel)
  1294         tty->print_cr("level (%d) exceeds MaxBCEAEstimateLevel (%d).",
  1295                       _level, (int) MaxBCEAEstimateLevel);
  1296       else if (method()->code_size() > MaxBCEAEstimateSize)
  1297         tty->print_cr("code size (%d) exceeds MaxBCEAEstimateSize (%d).",
  1298                       method()->code_size(), (int) MaxBCEAEstimateSize);
  1299       else
  1300         ShouldNotReachHere();
  1302     clear_escape_info();
  1304     return;
  1307   if (BCEATraceLevel >= 1) {
  1308     tty->print("[EA] estimating escape information for");
  1309     if (iid != vmIntrinsics::_none)
  1310       tty->print(" intrinsic");
  1311     method()->print_short_name();
  1312     tty->print_cr(" (%d bytes)", method()->code_size());
  1315   bool success;
  1317   initialize();
  1319   // Do not scan method if it has no object parameters and
  1320   // does not returns an object (_return_allocated is set in initialize()).
  1321   if (_arg_local.Size() == 0 && !_return_allocated) {
  1322     // Clear all info since method's bytecode was not analysed and
  1323     // set pessimistic escape information.
  1324     clear_escape_info();
  1325     methodData()->set_eflag(MethodData::allocated_escapes);
  1326     methodData()->set_eflag(MethodData::unknown_modified);
  1327     methodData()->set_eflag(MethodData::estimated);
  1328     return;
  1331   if (iid != vmIntrinsics::_none)
  1332     success = compute_escape_for_intrinsic(iid);
  1333   else {
  1334     success = do_analysis();
  1337   // don't store interprocedural escape information if it introduces
  1338   // dependencies or if method data is empty
  1339   //
  1340   if (!has_dependencies() && !methodData()->is_empty()) {
  1341     for (i = 0; i < _arg_size; i++) {
  1342       if (_arg_local.test(i)) {
  1343         assert(_arg_stack.test(i), "inconsistent escape info");
  1344         methodData()->set_arg_local(i);
  1345         methodData()->set_arg_stack(i);
  1346       } else if (_arg_stack.test(i)) {
  1347         methodData()->set_arg_stack(i);
  1349       if (_arg_returned.test(i)) {
  1350         methodData()->set_arg_returned(i);
  1352       methodData()->set_arg_modified(i, _arg_modified[i]);
  1354     if (_return_local) {
  1355       methodData()->set_eflag(MethodData::return_local);
  1357     if (_return_allocated) {
  1358       methodData()->set_eflag(MethodData::return_allocated);
  1360     if (_allocated_escapes) {
  1361       methodData()->set_eflag(MethodData::allocated_escapes);
  1363     if (_unknown_modified) {
  1364       methodData()->set_eflag(MethodData::unknown_modified);
  1366     methodData()->set_eflag(MethodData::estimated);
  1370 void BCEscapeAnalyzer::read_escape_info() {
  1371   assert(methodData()->has_escape_info(), "no escape info available");
  1373   // read escape information from method descriptor
  1374   for (int i = 0; i < _arg_size; i++) {
  1375     if (methodData()->is_arg_local(i))
  1376       _arg_local.set(i);
  1377     if (methodData()->is_arg_stack(i))
  1378       _arg_stack.set(i);
  1379     if (methodData()->is_arg_returned(i))
  1380       _arg_returned.set(i);
  1381     _arg_modified[i] = methodData()->arg_modified(i);
  1383   _return_local = methodData()->eflag_set(MethodData::return_local);
  1384   _return_allocated = methodData()->eflag_set(MethodData::return_allocated);
  1385   _allocated_escapes = methodData()->eflag_set(MethodData::allocated_escapes);
  1386   _unknown_modified = methodData()->eflag_set(MethodData::unknown_modified);
  1390 #ifndef PRODUCT
  1391 void BCEscapeAnalyzer::dump() {
  1392   tty->print("[EA] estimated escape information for");
  1393   method()->print_short_name();
  1394   tty->print_cr(has_dependencies() ? " (not stored)" : "");
  1395   tty->print("     non-escaping args:      ");
  1396   _arg_local.print_on(tty);
  1397   tty->print("     stack-allocatable args: ");
  1398   _arg_stack.print_on(tty);
  1399   if (_return_local) {
  1400     tty->print("     returned args:          ");
  1401     _arg_returned.print_on(tty);
  1402   } else if (is_return_allocated()) {
  1403     tty->print_cr("     return allocated value");
  1404   } else {
  1405     tty->print_cr("     return non-local value");
  1407   tty->print("     modified args: ");
  1408   for (int i = 0; i < _arg_size; i++) {
  1409     if (_arg_modified[i] == 0)
  1410       tty->print("    0");
  1411     else
  1412       tty->print("    0x%x", _arg_modified[i]);
  1414   tty->cr();
  1415   tty->print("     flags: ");
  1416   if (_return_allocated)
  1417     tty->print(" return_allocated");
  1418   if (_allocated_escapes)
  1419     tty->print(" allocated_escapes");
  1420   if (_unknown_modified)
  1421     tty->print(" unknown_modified");
  1422   tty->cr();
  1424 #endif
  1426 BCEscapeAnalyzer::BCEscapeAnalyzer(ciMethod* method, BCEscapeAnalyzer* parent)
  1427     : _conservative(method == NULL || !EstimateArgEscape)
  1428     , _arena(CURRENT_ENV->arena())
  1429     , _method(method)
  1430     , _methodData(method ? method->method_data() : NULL)
  1431     , _arg_size(method ? method->arg_size() : 0)
  1432     , _arg_local(_arena)
  1433     , _arg_stack(_arena)
  1434     , _arg_returned(_arena)
  1435     , _dirty(_arena)
  1436     , _return_local(false)
  1437     , _return_allocated(false)
  1438     , _allocated_escapes(false)
  1439     , _unknown_modified(false)
  1440     , _dependencies(_arena, 4, 0, NULL)
  1441     , _parent(parent)
  1442     , _level(parent == NULL ? 0 : parent->level() + 1) {
  1443   if (!_conservative) {
  1444     _arg_local.Clear();
  1445     _arg_stack.Clear();
  1446     _arg_returned.Clear();
  1447     _dirty.Clear();
  1448     Arena* arena = CURRENT_ENV->arena();
  1449     _arg_modified = (uint *) arena->Amalloc(_arg_size * sizeof(uint));
  1450     Copy::zero_to_bytes(_arg_modified, _arg_size * sizeof(uint));
  1452     if (methodData() == NULL)
  1453       return;
  1454     bool printit = _method->should_print_assembly();
  1455     if (methodData()->has_escape_info()) {
  1456       TRACE_BCEA(2, tty->print_cr("[EA] Reading previous results for %s.%s",
  1457                                   method->holder()->name()->as_utf8(),
  1458                                   method->name()->as_utf8()));
  1459       read_escape_info();
  1460     } else {
  1461       TRACE_BCEA(2, tty->print_cr("[EA] computing results for %s.%s",
  1462                                   method->holder()->name()->as_utf8(),
  1463                                   method->name()->as_utf8()));
  1465       compute_escape_info();
  1466       methodData()->update_escape_info();
  1468 #ifndef PRODUCT
  1469     if (BCEATraceLevel >= 3) {
  1470       // dump escape information
  1471       dump();
  1473 #endif
  1477 void BCEscapeAnalyzer::copy_dependencies(Dependencies *deps) {
  1478   if (ciEnv::current()->jvmti_can_hotswap_or_post_breakpoint()) {
  1479     // Also record evol dependencies so redefinition of the
  1480     // callee will trigger recompilation.
  1481     deps->assert_evol_method(method());
  1483   for (int i = 0; i < _dependencies.length(); i+=2) {
  1484     ciKlass *k = _dependencies.at(i)->as_klass();
  1485     ciMethod *m = _dependencies.at(i+1)->as_method();
  1486     deps->assert_unique_concrete_method(k, m);

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