Wed, 11 Jan 2012 17:34:02 -0500
7115199: Add event tracing hooks and Java Flight Recorder infrastructure
Summary: Added a nop tracing infrastructure, JFR makefile changes and other infrastructure used only by JFR.
Reviewed-by: acorn, sspitsyn
Contributed-by: markus.gronlund@oracle.com
1 /*
2 * Copyright (c) 1997, 2011, 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 */
25 #ifndef SHARE_VM_CLASSFILE_SYMBOLTABLE_HPP
26 #define SHARE_VM_CLASSFILE_SYMBOLTABLE_HPP
28 #include "memory/allocation.inline.hpp"
29 #include "oops/symbol.hpp"
30 #include "utilities/hashtable.hpp"
32 // The symbol table holds all Symbol*s and corresponding interned strings.
33 // Symbol*s and literal strings should be canonicalized.
34 //
35 // The interned strings are created lazily.
36 //
37 // It is implemented as an open hash table with a fixed number of buckets.
38 //
39 // %note:
40 // - symbolTableEntrys are allocated in blocks to reduce the space overhead.
42 class BoolObjectClosure;
45 // Class to hold a newly created or referenced Symbol* temporarily in scope.
46 // new_symbol() and lookup() will create a Symbol* if not already in the
47 // symbol table and add to the symbol's reference count.
48 // probe() and lookup_only() will increment the refcount if symbol is found.
49 class TempNewSymbol : public StackObj {
50 Symbol* _temp;
52 public:
53 TempNewSymbol() : _temp(NULL) {}
54 // Creating or looking up a symbol increments the symbol's reference count
55 TempNewSymbol(Symbol *s) : _temp(s) {}
57 // Operator= increments reference count.
58 void operator=(const TempNewSymbol &s) {
59 _temp = s._temp;
60 if (_temp !=NULL) _temp->increment_refcount();
61 }
63 // Decrement reference counter so it can go away if it's unique
64 ~TempNewSymbol() { if (_temp != NULL) _temp->decrement_refcount(); }
66 // Operators so they can be used like Symbols
67 Symbol* operator -> () const { return _temp; }
68 bool operator == (Symbol* o) const { return _temp == o; }
69 // Sneaky conversion function
70 operator Symbol*() { return _temp; }
71 };
73 class SymbolTable : public Hashtable<Symbol*> {
74 friend class VMStructs;
75 friend class ClassFileParser;
77 private:
78 // The symbol table
79 static SymbolTable* _the_table;
81 // For statistics
82 static int symbols_removed;
83 static int symbols_counted;
85 Symbol* allocate_symbol(const u1* name, int len, TRAPS); // Assumes no characters larger than 0x7F
86 bool allocate_symbols(int names_count, const u1** names, int* lengths, Symbol** syms, TRAPS);
88 // Adding elements
89 Symbol* basic_add(int index, u1* name, int len,
90 unsigned int hashValue, TRAPS);
91 bool basic_add(constantPoolHandle cp, int names_count,
92 const char** names, int* lengths, int* cp_indices,
93 unsigned int* hashValues, TRAPS);
95 static void new_symbols(constantPoolHandle cp, int names_count,
96 const char** name, int* lengths,
97 int* cp_indices, unsigned int* hashValues,
98 TRAPS) {
99 add(cp, names_count, name, lengths, cp_indices, hashValues, THREAD);
100 }
103 // Table size
104 enum {
105 symbol_table_size = 20011
106 };
108 Symbol* lookup(int index, const char* name, int len, unsigned int hash);
110 SymbolTable()
111 : Hashtable<Symbol*>(symbol_table_size, sizeof (HashtableEntry<Symbol*>)) {}
113 SymbolTable(HashtableBucket* t, int number_of_entries)
114 : Hashtable<Symbol*>(symbol_table_size, sizeof (HashtableEntry<Symbol*>), t,
115 number_of_entries) {}
118 public:
119 enum {
120 symbol_alloc_batch_size = 8
121 };
123 // The symbol table
124 static SymbolTable* the_table() { return _the_table; }
126 static void create_table() {
127 assert(_the_table == NULL, "One symbol table allowed.");
128 _the_table = new SymbolTable();
129 }
131 static void create_table(HashtableBucket* t, int length,
132 int number_of_entries) {
133 assert(_the_table == NULL, "One symbol table allowed.");
134 assert(length == symbol_table_size * sizeof(HashtableBucket),
135 "bad shared symbol size.");
136 _the_table = new SymbolTable(t, number_of_entries);
137 }
139 static Symbol* lookup(const char* name, int len, TRAPS);
140 // lookup only, won't add. Also calculate hash.
141 static Symbol* lookup_only(const char* name, int len, unsigned int& hash);
142 // Only copy to C string to be added if lookup failed.
143 static Symbol* lookup(const Symbol* sym, int begin, int end, TRAPS);
145 static void release(Symbol* sym);
147 // Look up the address of the literal in the SymbolTable for this Symbol*
148 static Symbol** lookup_symbol_addr(Symbol* sym);
150 // jchar (utf16) version of lookups
151 static Symbol* lookup_unicode(const jchar* name, int len, TRAPS);
152 static Symbol* lookup_only_unicode(const jchar* name, int len, unsigned int& hash);
154 static void add(constantPoolHandle cp, int names_count,
155 const char** names, int* lengths, int* cp_indices,
156 unsigned int* hashValues, TRAPS);
158 // Release any dead symbols
159 static void unlink();
161 // iterate over symbols
162 static void symbols_do(SymbolClosure *cl);
164 // Symbol creation
165 static Symbol* new_symbol(const char* utf8_buffer, int length, TRAPS) {
166 assert(utf8_buffer != NULL, "just checking");
167 return lookup(utf8_buffer, length, THREAD);
168 }
169 static Symbol* new_symbol(const char* name, TRAPS) {
170 return new_symbol(name, (int)strlen(name), THREAD);
171 }
172 static Symbol* new_symbol(const Symbol* sym, int begin, int end, TRAPS) {
173 assert(begin <= end && end <= sym->utf8_length(), "just checking");
174 return lookup(sym, begin, end, THREAD);
175 }
177 // Symbol lookup
178 static Symbol* lookup(int index, const char* name, int len, TRAPS);
180 // Needed for preloading classes in signatures when compiling.
181 // Returns the symbol is already present in symbol table, otherwise
182 // NULL. NO ALLOCATION IS GUARANTEED!
183 static Symbol* probe(const char* name, int len) {
184 unsigned int ignore_hash;
185 return lookup_only(name, len, ignore_hash);
186 }
187 static Symbol* probe_unicode(const jchar* name, int len) {
188 unsigned int ignore_hash;
189 return lookup_only_unicode(name, len, ignore_hash);
190 }
192 // Histogram
193 static void print_histogram() PRODUCT_RETURN;
194 static void print() PRODUCT_RETURN;
196 // Debugging
197 static void verify();
199 // Sharing
200 static void copy_buckets(char** top, char*end) {
201 the_table()->Hashtable<Symbol*>::copy_buckets(top, end);
202 }
203 static void copy_table(char** top, char*end) {
204 the_table()->Hashtable<Symbol*>::copy_table(top, end);
205 }
206 static void reverse(void* boundary = NULL) {
207 the_table()->Hashtable<Symbol*>::reverse(boundary);
208 }
209 };
211 class StringTable : public Hashtable<oop> {
212 friend class VMStructs;
214 private:
215 // The string table
216 static StringTable* _the_table;
218 static oop intern(Handle string_or_null, jchar* chars, int length, TRAPS);
219 oop basic_add(int index, Handle string_or_null, jchar* name, int len,
220 unsigned int hashValue, TRAPS);
222 oop lookup(int index, jchar* chars, int length, unsigned int hashValue);
224 StringTable() : Hashtable<oop>((int)StringTableSize,
225 sizeof (HashtableEntry<oop>)) {}
227 StringTable(HashtableBucket* t, int number_of_entries)
228 : Hashtable<oop>((int)StringTableSize, sizeof (HashtableEntry<oop>), t,
229 number_of_entries) {}
231 public:
232 // The string table
233 static StringTable* the_table() { return _the_table; }
235 static void create_table() {
236 assert(_the_table == NULL, "One string table allowed.");
237 _the_table = new StringTable();
238 }
240 static void create_table(HashtableBucket* t, int length,
241 int number_of_entries) {
242 assert(_the_table == NULL, "One string table allowed.");
243 assert((size_t)length == StringTableSize * sizeof(HashtableBucket),
244 "bad shared string size.");
245 _the_table = new StringTable(t, number_of_entries);
246 }
248 // GC support
249 // Delete pointers to otherwise-unreachable objects.
250 static void unlink(BoolObjectClosure* cl);
252 // Invoke "f->do_oop" on the locations of all oops in the table.
253 static void oops_do(OopClosure* f);
255 // Probing
256 static oop lookup(Symbol* symbol);
258 // Interning
259 static oop intern(Symbol* symbol, TRAPS);
260 static oop intern(oop string, TRAPS);
261 static oop intern(const char *utf8_string, TRAPS);
263 // Debugging
264 static void verify();
266 // Sharing
267 static void copy_buckets(char** top, char*end) {
268 the_table()->Hashtable<oop>::copy_buckets(top, end);
269 }
270 static void copy_table(char** top, char*end) {
271 the_table()->Hashtable<oop>::copy_table(top, end);
272 }
273 static void reverse() {
274 the_table()->Hashtable<oop>::reverse();
275 }
276 };
278 #endif // SHARE_VM_CLASSFILE_SYMBOLTABLE_HPP