bcEscapeAnalyzer.hpp revision 196:d1605aabd0a1 
1/*
2 * Copyright 2005-2008 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
24
25define_array(ciObjectArray, ciObject*);
26define_stack(ciObjectList, ciObjectArray);
27
28// This class implements a fast, conservative analysis of effect of methods
29// on the escape state of their arguments.  The analysis is at the bytecode
30// level.
31
32class  ciMethodBlocks;
33class  ciBlock;
34
35class BCEscapeAnalyzer : public ResourceObj {
36 private:
37  bool              _conservative; // If true, return maximally
38                                   // conservative results.
39  ciMethod*         _method;
40  ciMethodData*     _methodData;
41  int               _arg_size;
42
43  intStack          _stack;
44
45  BitMap            _arg_local;
46  BitMap            _arg_stack;
47  BitMap            _arg_returned;
48  BitMap            _dirty;
49  enum{ ARG_OFFSET_MAX = 31};
50  uint              *_arg_modified;
51
52  bool              _return_local;
53  bool              _return_allocated;
54  bool              _allocated_escapes;
55  bool              _unknown_modified;
56
57  ciObjectList     _dependencies;
58
59  ciMethodBlocks   *_methodBlocks;
60
61  BCEscapeAnalyzer* _parent;
62  int               _level;
63
64  class  ArgumentMap;
65  class  StateInfo;
66
67  // helper functions
68  bool is_argument(int i)    { return i >= 0 && i < _arg_size; }
69
70  void raw_push(int i)       { _stack.push(i); }
71  int  raw_pop()             { return _stack.is_empty() ? -1 : _stack.pop(); }
72  void apush(int i)          { raw_push(i); }
73  void spush()               { raw_push(-1); }
74  void lpush()               { spush(); spush(); }
75  int  apop()                { return raw_pop(); }
76  void spop()                { assert(_stack.is_empty() || _stack.top() == -1, ""); raw_pop(); }
77  void lpop()                { spop(); spop(); }
78
79  void set_returned(ArgumentMap vars);
80  bool is_argument(ArgumentMap vars);
81  bool is_arg_stack(ArgumentMap vars);
82  void clear_bits(ArgumentMap vars, BitMap &bs);
83  void set_method_escape(ArgumentMap vars);
84  void set_global_escape(ArgumentMap vars);
85  void set_dirty(ArgumentMap vars);
86  void set_modified(ArgumentMap vars, int offs, int size);
87
88  bool is_recursive_call(ciMethod* callee);
89  void add_dependence(ciKlass *klass, ciMethod *meth);
90  void propagate_dependencies(ciMethod *meth);
91  void invoke(StateInfo &state, Bytecodes::Code code, ciMethod* target, ciKlass* holder);
92
93  void iterate_one_block(ciBlock *blk, StateInfo &state, GrowableArray<ciBlock *> &successors);
94  void iterate_blocks(Arena *);
95  void merge_block_states(StateInfo *blockstates, ciBlock *dest, StateInfo *s_state);
96
97  // analysis
98  void initialize();
99  void clear_escape_info();
100  void compute_escape_info();
101  vmIntrinsics::ID known_intrinsic();
102  bool compute_escape_for_intrinsic(vmIntrinsics::ID iid);
103  bool do_analysis();
104
105  void read_escape_info();
106
107  bool contains(uint arg_set1, uint arg_set2);
108
109 public:
110  BCEscapeAnalyzer(ciMethod* method, BCEscapeAnalyzer* parent = NULL);
111
112  // accessors
113  ciMethod*         method() const               { return _method; }
114  ciMethodData*     methodData() const           { return _methodData; }
115  BCEscapeAnalyzer* parent() const               { return _parent; }
116  int               level() const                { return _level; }
117  ciObjectList*     dependencies()               { return &_dependencies; }
118  bool              has_dependencies() const     { return !_dependencies.is_empty(); }
119
120  // retrieval of interprocedural escape information
121
122  // The given argument does not escape the callee.
123  bool is_arg_local(int i) const {
124    return !_conservative && _arg_local.at(i);
125  }
126
127  // The given argument escapes the callee, but does not become globally
128  // reachable.
129  bool is_arg_stack(int i) const {
130    return !_conservative && _arg_stack.at(i);
131  }
132
133  // The given argument does not escape globally, and may be returned.
134  bool is_arg_returned(int i) const {
135    return !_conservative && _arg_returned.at(i); }
136
137  // True iff only input arguments are returned.
138  bool is_return_local() const {
139    return !_conservative && _return_local;
140  }
141
142  // True iff only newly allocated unescaped objects are returned.
143  bool is_return_allocated() const {
144    return !_conservative && _return_allocated && !_allocated_escapes;
145  }
146
147  // Tracking of argument modification
148
149  enum {OFFSET_ANY = -1};
150  bool is_arg_modified(int arg, int offset, int size_in_bytes);
151  void set_arg_modified(int arg, int offset, int size_in_bytes);
152  bool has_non_arg_side_affects()    { return _unknown_modified; }
153
154  // Copy dependencies from this analysis into "deps"
155  void copy_dependencies(Dependencies *deps);
156
157#ifndef PRODUCT
158  // dump escape information
159  void dump();
160#endif
161};
162