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 /*

  * Copyright (c) 2005, 2012, Oracle and/or its affiliates. All rights reserved.

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.

  *

  * This code is distributed in the hope that it will be useful, but WITHOUT

  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

  * or visit www.oracle.com if you need additional information or have any

  * questions.

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  */

 #ifndef SHARE_VM_CI_BCESCAPEANALYZER_HPP

 #define SHARE_VM_CI_BCESCAPEANALYZER_HPP

 #ifdef COMPILER2

 #include "ci/ciObject.hpp"

 #include "ci/ciMethod.hpp"

 #include "ci/ciMethodData.hpp"

 #include "code/dependencies.hpp"

 #include "libadt/vectset.hpp"

 #include "memory/allocation.hpp"

 #include "utilities/growableArray.hpp"

 #endif

 // This class implements a fast, conservative analysis of effect of methods

 // on the escape state of their arguments.  The analysis is at the bytecode

 // level.

 class  ciMethodBlocks;

 class  ciBlock;

 class BCEscapeAnalyzer : public ResourceObj {

  private:

   Arena*            _arena;        // ciEnv arena

   bool              _conservative; // If true, return maximally

                                    // conservative results.

   ciMethod*         _method;

   ciMethodData*     _methodData;

   int               _arg_size;

   VectorSet         _arg_local;

   VectorSet         _arg_stack;

   VectorSet         _arg_returned;

   VectorSet         _dirty;

   enum{ ARG_OFFSET_MAX = 31};

   uint              *_arg_modified;

   bool              _return_local;

   bool              _return_allocated;

   bool              _allocated_escapes;

   bool              _unknown_modified;

   GrowableArray<ciMetadata *> _dependencies;

   ciMethodBlocks   *_methodBlocks;

   BCEscapeAnalyzer* _parent;

   int               _level;

  public:

   class  ArgumentMap;

   class  StateInfo;

  private:

   // helper functions

   bool is_argument(int i)    { return i >= 0 && i < _arg_size; }

   void set_returned(ArgumentMap vars);

   bool is_argument(ArgumentMap vars);

   bool is_arg_stack(ArgumentMap vars);

   bool returns_all(ArgumentMap vars);

   void clear_bits(ArgumentMap vars, VectorSet &bs);

   void set_method_escape(ArgumentMap vars);

   void set_global_escape(ArgumentMap vars, bool merge = false);

   void set_dirty(ArgumentMap vars);

   void set_modified(ArgumentMap vars, int offs, int size);

   bool is_recursive_call(ciMethod* callee);

   void add_dependence(ciKlass *klass, ciMethod *meth);

   void propagate_dependencies(ciMethod *meth);

   void invoke(StateInfo &state, Bytecodes::Code code, ciMethod* target, ciKlass* holder);

   void iterate_one_block(ciBlock *blk, StateInfo &state, GrowableArray<ciBlock *> &successors);

   void iterate_blocks(Arena *);

   void merge_block_states(StateInfo *blockstates, ciBlock *dest, StateInfo *s_state);

   // analysis

   void initialize();

   void clear_escape_info();

   void compute_escape_info();

   vmIntrinsics::ID known_intrinsic();

   bool compute_escape_for_intrinsic(vmIntrinsics::ID iid);

   bool do_analysis();

   void read_escape_info();

   bool contains(uint arg_set1, uint arg_set2);

  public:

   BCEscapeAnalyzer(ciMethod* method, BCEscapeAnalyzer* parent = NULL);

   // accessors

   ciMethod*         method() const               { return _method; }

   ciMethodData*     methodData() const           { return _methodData; }

   BCEscapeAnalyzer* parent() const               { return _parent; }

   int               level() const                { return _level; }

   GrowableArray<ciMetadata *>* dependencies()    { return &_dependencies; }

   bool              has_dependencies() const     { return !_dependencies.is_empty(); }

   // retrieval of interprocedural escape information

   // The given argument does not escape the callee.

   bool is_arg_local(int i) const {

     return !_conservative && _arg_local.test(i);

   }

   // The given argument escapes the callee, but does not become globally

   // reachable.

   bool is_arg_stack(int i) const {

     return !_conservative && _arg_stack.test(i);

   }

   // The given argument does not escape globally, and may be returned.

   bool is_arg_returned(int i) const {

     return !_conservative && _arg_returned.test(i); }

   // True iff only input arguments are returned.

   bool is_return_local() const {

     return !_conservative && _return_local;

   }

   // True iff only newly allocated unescaped objects are returned.

   bool is_return_allocated() const {

     return !_conservative && _return_allocated && !_allocated_escapes;

   }

   // Tracking of argument modification

   enum {OFFSET_ANY = -1};

   bool is_arg_modified(int arg, int offset, int size_in_bytes);

   void set_arg_modified(int arg, int offset, int size_in_bytes);

   bool has_non_arg_side_affects()    { return _unknown_modified; }

   // Copy dependencies from this analysis into "deps"

   void copy_dependencies(Dependencies *deps);

 #ifndef PRODUCT

   // dump escape information

   void dump();

 #endif

 };

 #endif // SHARE_VM_CI_BCESCAPEANALYZER_HPP