comparison src/share/vm/classfile/symbolTable.hpp @ 0:a61af66fc99e

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author duke
date Sat, 01 Dec 2007 00:00:00 +0000
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1 /*
2 * Copyright 1997-2006 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
25 // The symbol table holds all symbolOops and corresponding interned strings.
26 // symbolOops and literal strings should be canonicalized.
27 //
28 // The interned strings are created lazily.
29 //
30 // It is implemented as an open hash table with a fixed number of buckets.
31 //
32 // %note:
33 // - symbolTableEntrys are allocated in blocks to reduce the space overhead.
34
35 class BoolObjectClosure;
36
37
38 class SymbolTable : public Hashtable {
39 friend class VMStructs;
40
41 private:
42 // The symbol table
43 static SymbolTable* _the_table;
44
45 // Adding elements
46 symbolOop basic_add(int index, u1* name, int len,
47 unsigned int hashValue, TRAPS);
48 bool basic_add(constantPoolHandle cp, int names_count,
49 const char** names, int* lengths, int* cp_indices,
50 unsigned int* hashValues, TRAPS);
51
52 // Table size
53 enum {
54 symbol_table_size = 20011
55 };
56
57 symbolOop lookup(int index, const char* name, int len, unsigned int hash);
58
59 SymbolTable()
60 : Hashtable(symbol_table_size, sizeof (HashtableEntry)) {}
61
62 SymbolTable(HashtableBucket* t, int number_of_entries)
63 : Hashtable(symbol_table_size, sizeof (HashtableEntry), t,
64 number_of_entries) {}
65
66
67 public:
68 enum {
69 symbol_alloc_batch_size = 8
70 };
71
72 // The symbol table
73 static SymbolTable* the_table() { return _the_table; }
74
75 static void create_table() {
76 assert(_the_table == NULL, "One symbol table allowed.");
77 _the_table = new SymbolTable();
78 }
79
80 static void create_table(HashtableBucket* t, int length,
81 int number_of_entries) {
82 assert(_the_table == NULL, "One symbol table allowed.");
83 assert(length == symbol_table_size * sizeof(HashtableBucket),
84 "bad shared symbol size.");
85 _the_table = new SymbolTable(t, number_of_entries);
86 }
87
88 static symbolOop lookup(const char* name, int len, TRAPS);
89 // lookup only, won't add. Also calculate hash.
90 static symbolOop lookup_only(const char* name, int len, unsigned int& hash);
91 // Only copy to C string to be added if lookup failed.
92 static symbolOop lookup(symbolHandle sym, int begin, int end, TRAPS);
93
94 static void add(constantPoolHandle cp, int names_count,
95 const char** names, int* lengths, int* cp_indices,
96 unsigned int* hashValues, TRAPS);
97
98 // GC support
99 // Delete pointers to otherwise-unreachable objects.
100 static void unlink(BoolObjectClosure* cl) {
101 the_table()->Hashtable::unlink(cl);
102 }
103
104 // Invoke "f->do_oop" on the locations of all oops in the table.
105 static void oops_do(OopClosure* f) {
106 the_table()->Hashtable::oops_do(f);
107 }
108
109 // Symbol lookup
110 static symbolOop lookup(int index, const char* name, int len, TRAPS);
111
112 // Needed for preloading classes in signatures when compiling.
113 // Returns the symbol is already present in symbol table, otherwise
114 // NULL. NO ALLOCATION IS GUARANTEED!
115 static symbolOop probe(const char* name, int len);
116
117 // Histogram
118 static void print_histogram() PRODUCT_RETURN;
119
120 // Debugging
121 static void verify();
122
123 // Sharing
124 static void copy_buckets(char** top, char*end) {
125 the_table()->Hashtable::copy_buckets(top, end);
126 }
127 static void copy_table(char** top, char*end) {
128 the_table()->Hashtable::copy_table(top, end);
129 }
130 static void reverse(void* boundary = NULL) {
131 ((Hashtable*)the_table())->reverse(boundary);
132 }
133 };
134
135
136 class StringTable : public Hashtable {
137 friend class VMStructs;
138
139 private:
140 // The string table
141 static StringTable* _the_table;
142
143 static oop intern(Handle string_or_null, jchar* chars, int length, TRAPS);
144 oop basic_add(int index, Handle string_or_null, jchar* name, int len,
145 unsigned int hashValue, TRAPS);
146
147 // Table size
148 enum {
149 string_table_size = 1009
150 };
151
152 oop lookup(int index, jchar* chars, int length, unsigned int hashValue);
153
154 StringTable() : Hashtable(string_table_size, sizeof (HashtableEntry)) {}
155
156 StringTable(HashtableBucket* t, int number_of_entries)
157 : Hashtable(string_table_size, sizeof (HashtableEntry), t,
158 number_of_entries) {}
159
160 public:
161 // The string table
162 static StringTable* the_table() { return _the_table; }
163
164 static void create_table() {
165 assert(_the_table == NULL, "One string table allowed.");
166 _the_table = new StringTable();
167 }
168
169 static void create_table(HashtableBucket* t, int length,
170 int number_of_entries) {
171 assert(_the_table == NULL, "One string table allowed.");
172 assert(length == string_table_size * sizeof(HashtableBucket),
173 "bad shared string size.");
174 _the_table = new StringTable(t, number_of_entries);
175 }
176
177
178 static int hash_string(jchar* s, int len);
179
180
181 // GC support
182 // Delete pointers to otherwise-unreachable objects.
183 static void unlink(BoolObjectClosure* cl) {
184 the_table()->Hashtable::unlink(cl);
185 }
186
187 // Invoke "f->do_oop" on the locations of all oops in the table.
188 static void oops_do(OopClosure* f) {
189 the_table()->Hashtable::oops_do(f);
190 }
191
192 // Probing
193 static oop lookup(symbolOop symbol);
194
195 // Interning
196 static oop intern(symbolOop symbol, TRAPS);
197 static oop intern(oop string, TRAPS);
198 static oop intern(const char *utf8_string, TRAPS);
199
200 // Debugging
201 static void verify();
202
203 // Sharing
204 static void copy_buckets(char** top, char*end) {
205 the_table()->Hashtable::copy_buckets(top, end);
206 }
207 static void copy_table(char** top, char*end) {
208 the_table()->Hashtable::copy_table(top, end);
209 }
210 static void reverse() {
211 ((BasicHashtable*)the_table())->reverse();
212 }
213 };