1 /*
   2  * Copyright (c) 2005, 2013, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_CI_BCESCAPEANALYZER_HPP
  26 #define SHARE_VM_CI_BCESCAPEANALYZER_HPP
  27 
  28 #ifdef COMPILER2
  29 #include "ci/ciObject.hpp"
  30 #include "ci/ciMethod.hpp"
  31 #include "ci/ciMethodData.hpp"
  32 #include "code/dependencies.hpp"
  33 #include "libadt/vectset.hpp"
  34 #include "memory/allocation.hpp"
  35 #include "utilities/growableArray.hpp"
  36 #endif
  37 
  38 // This class implements a fast, conservative analysis of effect of methods
  39 // on the escape state of their arguments.  The analysis is at the bytecode
  40 // level.
  41 
  42 class  ciMethodBlocks;
  43 class  ciBlock;
  44 
  45 class BCEscapeAnalyzer : public ResourceObj {
  46  private:
  47   Arena*            _arena;        // ciEnv arena
  48 
  49   bool              _conservative; // If true, return maximally
  50                                    // conservative results.
  51   ciMethod*         _method;
  52   ciMethodData*     _methodData;
  53   int               _arg_size;
  54   VectorSet         _arg_local;
  55   VectorSet         _arg_stack;
  56   VectorSet         _arg_returned;
  57   VectorSet         _dirty;
  58   enum{ ARG_OFFSET_MAX = 31};
  59   uint              *_arg_modified;
  60 
  61   bool              _return_local;
  62   bool              _return_allocated;
  63   bool              _allocated_escapes;
  64   bool              _unknown_modified;
  65 
  66   GrowableArray<ciMetadata *> _dependencies;
  67 
  68   ciMethodBlocks   *_methodBlocks;
  69 
  70   BCEscapeAnalyzer* _parent;
  71   int               _level;
  72 
  73  public:
  74   class  ArgumentMap;
  75   class  StateInfo;
  76 
  77  private:
  78   // helper functions
  79   bool is_argument(int i)    { return i >= 0 && i < _arg_size; }
  80   void set_returned(ArgumentMap vars);
  81   bool is_argument(ArgumentMap vars);
  82   bool is_arg_stack(ArgumentMap vars);
  83   bool returns_all(ArgumentMap vars);
  84   void clear_bits(ArgumentMap vars, VectorSet &bs);
  85   void set_method_escape(ArgumentMap vars);
  86   void set_global_escape(ArgumentMap vars, bool merge = false);
  87   void set_dirty(ArgumentMap vars);
  88   void set_modified(ArgumentMap vars, int offs, int size);
  89 
  90   bool is_recursive_call(ciMethod* callee);
  91   void add_dependence(ciKlass *klass, ciMethod *meth);
  92   void propagate_dependencies(ciMethod *meth);
  93   void invoke(StateInfo &state, Bytecodes::Code code, ciMethod* target, ciKlass* holder);
  94 
  95   void iterate_one_block(ciBlock *blk, StateInfo &state, GrowableArray<ciBlock *> &successors);
  96   void iterate_blocks(Arena *);
  97   void merge_block_states(StateInfo *blockstates, ciBlock *dest, StateInfo *s_state);
  98 
  99   // analysis
 100   void initialize();
 101   void clear_escape_info();
 102   void compute_escape_info();
 103   vmIntrinsics::ID known_intrinsic();
 104   bool compute_escape_for_intrinsic(vmIntrinsics::ID iid);
 105   bool do_analysis();
 106 
 107   void read_escape_info();
 108 
 109   bool contains(uint arg_set1, uint arg_set2);
 110 
 111  public:
 112   BCEscapeAnalyzer(ciMethod* method, BCEscapeAnalyzer* parent = NULL);
 113 
 114   // accessors
 115   ciMethod*         method() const               { return _method; }
 116   ciMethodData*     methodData() const           { return _methodData; }
 117   BCEscapeAnalyzer* parent() const               { return _parent; }
 118   int               level() const                { return _level; }
 119   GrowableArray<ciMetadata *>* dependencies()    { return &_dependencies; }
 120   bool              has_dependencies() const     { return !_dependencies.is_empty(); }
 121 
 122   // retrieval of interprocedural escape information
 123 
 124   // The given argument does not escape the callee.
 125   bool is_arg_local(int i) const {
 126     return !_conservative && _arg_local.test(i);
 127   }
 128 
 129   // The given argument escapes the callee, but does not become globally
 130   // reachable.
 131   bool is_arg_stack(int i) const {
 132     return !_conservative && _arg_stack.test(i);
 133   }
 134 
 135   // The given argument does not escape globally, and may be returned.
 136   bool is_arg_returned(int i) const {
 137     return !_conservative && _arg_returned.test(i); }
 138 
 139   // True iff only input arguments are returned.
 140   bool is_return_local() const {
 141     return !_conservative && _return_local;
 142   }
 143 
 144   // True iff only newly allocated unescaped objects are returned.
 145   bool is_return_allocated() const {
 146     return !_conservative && _return_allocated && !_allocated_escapes;
 147   }
 148 
 149   // Tracking of argument modification
 150 
 151   enum {OFFSET_ANY = -1};
 152   bool is_arg_modified(int arg, int offset, int size_in_bytes);
 153   void set_arg_modified(int arg, int offset, int size_in_bytes);
 154   bool has_non_arg_side_affects()    { return _unknown_modified; }
 155 
 156   // Copy dependencies from this analysis into "deps"
 157   void copy_dependencies(Dependencies *deps);
 158 
 159 #ifndef PRODUCT
 160   // dump escape information
 161   void dump();
 162 #endif
 163 };
 164 
 165 #endif // SHARE_VM_CI_BCESCAPEANALYZER_HPP