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