Mercurial > hg > graal-compiler
annotate src/share/vm/interpreter/oopMapCache.hpp @ 3992:d1bdeef3e3e2
7098282: G1: assert(interval >= 0) failed: Sanity check, referencePolicy.cpp: 76
Summary: There is a race between one thread successfully forwarding and copying the klass mirror for the SoftReference class (including the static master clock) and another thread attempting to use the master clock while attempting to discover a soft reference object. Maintain a shadow copy of the soft reference master clock and use the shadow during reference discovery and reference processing.
Reviewed-by: tonyp, brutisso, ysr
author | johnc |
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date | Wed, 12 Oct 2011 10:25:51 -0700 |
parents | c760f78e0a53 |
children | d2a62e0f25eb |
rev | line source |
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0 | 1 /* |
1972 | 2 * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved. |
0 | 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 * | |
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
0 | 22 * |
23 */ | |
24 | |
1972 | 25 #ifndef SHARE_VM_INTERPRETER_OOPMAPCACHE_HPP |
26 #define SHARE_VM_INTERPRETER_OOPMAPCACHE_HPP | |
27 | |
28 #include "oops/generateOopMap.hpp" | |
1983
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29 #include "runtime/mutex.hpp" |
1972 | 30 |
0 | 31 // A Cache for storing (method, bci) -> oopMap. |
32 // The memory management system uses the cache when locating object | |
33 // references in an interpreted frame. | |
34 // | |
35 // OopMapCache's are allocated lazily per instanceKlass. | |
36 | |
37 // The oopMap (InterpreterOopMap) is stored as a bit mask. If the | |
38 // bit_mask can fit into two words it is stored in | |
39 // the _bit_mask array, otherwise it is allocated on the heap. | |
40 // For OopMapCacheEntry the bit_mask is allocated in the C heap | |
41 // because these entries persist between garbage collections. | |
42 // For InterpreterOopMap the bit_mask is allocated in | |
43 // a resource area for better performance. InterpreterOopMap | |
44 // should only be created and deleted during same garbage collection. | |
45 // | |
46 // If ENABBLE_ZAP_DEAD_LOCALS is defined, two bits are used | |
47 // per entry instead of one. In all cases, | |
48 // the first bit is set to indicate oops as opposed to other | |
49 // values. If the second bit is available, | |
50 // it is set for dead values. We get the following encoding: | |
51 // | |
52 // 00 live value | |
53 // 01 live oop | |
54 // 10 dead value | |
55 // 11 <unused> (we cannot distinguish between dead oops or values with the current oop map generator) | |
56 | |
57 | |
58 class OffsetClosure { | |
59 public: | |
60 virtual void offset_do(int offset) = 0; | |
61 }; | |
62 | |
63 | |
64 class InterpreterOopMap: ResourceObj { | |
65 friend class OopMapCache; | |
66 | |
67 public: | |
68 enum { | |
69 N = 2, // the number of words reserved | |
70 // for inlined mask storage | |
71 small_mask_limit = N * BitsPerWord, // the maximum number of bits | |
72 // available for small masks, | |
73 // small_mask_limit can be set to 0 | |
74 // for testing bit_mask allocation | |
75 | |
76 #ifdef ENABLE_ZAP_DEAD_LOCALS | |
77 bits_per_entry = 2, | |
78 dead_bit_number = 1, | |
79 #else | |
80 bits_per_entry = 1, | |
81 #endif | |
82 oop_bit_number = 0 | |
83 }; | |
84 | |
85 private: | |
86 methodOop _method; // the method for which the mask is valid | |
87 unsigned short _bci; // the bci for which the mask is valid | |
88 int _mask_size; // the mask size in bits | |
89 int _expression_stack_size; // the size of the expression stack in slots | |
90 | |
91 protected: | |
92 intptr_t _bit_mask[N]; // the bit mask if | |
93 // mask_size <= small_mask_limit, | |
94 // ptr to bit mask otherwise | |
95 // "protected" so that sub classes can | |
96 // access it without using trickery in | |
97 // methd bit_mask(). | |
98 #ifdef ASSERT | |
99 bool _resource_allocate_bit_mask; | |
100 #endif | |
101 | |
102 // access methods | |
103 methodOop method() const { return _method; } | |
104 void set_method(methodOop v) { _method = v; } | |
105 int bci() const { return _bci; } | |
106 void set_bci(int v) { _bci = v; } | |
107 int mask_size() const { return _mask_size; } | |
108 void set_mask_size(int v) { _mask_size = v; } | |
109 int number_of_entries() const { return mask_size() / bits_per_entry; } | |
110 // Test bit mask size and return either the in-line bit mask or allocated | |
111 // bit mask. | |
112 uintptr_t* bit_mask() { return (uintptr_t*)(mask_size() <= small_mask_limit ? (intptr_t)_bit_mask : _bit_mask[0]); } | |
113 | |
114 // return the word size of_bit_mask. mask_size() <= 4 * MAX_USHORT | |
115 size_t mask_word_size() { | |
116 return (mask_size() + BitsPerWord - 1) / BitsPerWord; | |
117 } | |
118 | |
119 uintptr_t entry_at(int offset) { int i = offset * bits_per_entry; return bit_mask()[i / BitsPerWord] >> (i % BitsPerWord); } | |
120 | |
121 void set_expression_stack_size(int sz) { _expression_stack_size = sz; } | |
122 | |
123 #ifdef ENABLE_ZAP_DEAD_LOCALS | |
124 bool is_dead(int offset) { return (entry_at(offset) & (1 << dead_bit_number)) != 0; } | |
125 #endif | |
126 | |
127 // Lookup | |
128 bool match(methodHandle method, int bci) { return _method == method() && _bci == bci; } | |
129 bool is_empty(); | |
130 | |
131 // Initialization | |
132 void initialize(); | |
133 | |
134 public: | |
135 InterpreterOopMap(); | |
136 ~InterpreterOopMap(); | |
137 | |
138 // Copy the OopMapCacheEntry in parameter "from" into this | |
139 // InterpreterOopMap. If the _bit_mask[0] in "from" points to | |
140 // allocated space (i.e., the bit mask was to large to hold | |
141 // in-line), allocate the space from a Resource area. | |
142 void resource_copy(OopMapCacheEntry* from); | |
143 | |
144 void iterate_oop(OffsetClosure* oop_closure); | |
145 void oop_iterate(OopClosure * blk); | |
146 void oop_iterate(OopClosure * blk, MemRegion mr); | |
147 void verify(); | |
148 void print(); | |
149 | |
150 bool is_oop (int offset) { return (entry_at(offset) & (1 << oop_bit_number )) != 0; } | |
151 | |
152 int expression_stack_size() { return _expression_stack_size; } | |
153 | |
154 #ifdef ENABLE_ZAP_DEAD_LOCALS | |
155 void iterate_all(OffsetClosure* oop_closure, OffsetClosure* value_closure, OffsetClosure* dead_closure); | |
156 #endif | |
157 }; | |
158 | |
159 class OopMapCache : public CHeapObj { | |
160 private: | |
161 enum { _size = 32, // Use fixed size for now | |
162 _probe_depth = 3 // probe depth in case of collisions | |
163 }; | |
164 | |
165 OopMapCacheEntry* _array; | |
166 | |
167 unsigned int hash_value_for(methodHandle method, int bci); | |
168 OopMapCacheEntry* entry_at(int i) const; | |
169 | |
170 Mutex _mut; | |
171 | |
172 void flush(); | |
173 | |
174 public: | |
175 OopMapCache(); | |
176 ~OopMapCache(); // free up memory | |
177 | |
178 // flush cache entry is occupied by an obsolete method | |
179 void flush_obsolete_entries(); | |
180 | |
181 // Returns the oopMap for (method, bci) in parameter "entry". | |
182 // Returns false if an oop map was not found. | |
183 void lookup(methodHandle method, int bci, InterpreterOopMap* entry); | |
184 | |
185 // Compute an oop map without updating the cache or grabbing any locks (for debugging) | |
186 static void compute_one_oop_map(methodHandle method, int bci, InterpreterOopMap* entry); | |
187 | |
188 // Helpers | |
189 // Iterate over the entries in the cached OopMapCacheEntry's | |
190 void oop_iterate(OopClosure *blk); | |
191 void oop_iterate(OopClosure *blk, MemRegion mr); | |
192 void verify(); | |
193 | |
194 // Returns total no. of bytes allocated as part of OopMapCache's | |
195 static long memory_usage() PRODUCT_RETURN0; | |
196 }; | |
1972 | 197 |
198 #endif // SHARE_VM_INTERPRETER_OOPMAPCACHE_HPP |