56
57 // Operator= increments reference count.
58 void operator=(const TempNewSymbol &s) {
59 //clear(); //FIXME
60 _temp = s._temp;
61 if (_temp !=NULL) _temp->increment_refcount();
62 }
63
64 // Decrement reference counter so it can go away if it's unique
65 void clear() { if (_temp != NULL) _temp->decrement_refcount(); _temp = NULL; }
66
67 ~TempNewSymbol() { clear(); }
68
69 // Operators so they can be used like Symbols
70 Symbol* operator -> () const { return _temp; }
71 bool operator == (Symbol* o) const { return _temp == o; }
72 // Sneaky conversion function
73 operator Symbol*() { return _temp; }
74 };
75
76 class SymbolTable : public RehashableHashtable<Symbol*, mtSymbol> {
77 friend class VMStructs;
78 friend class ClassFileParser;
79
80 private:
81 // The symbol table
82 static SymbolTable* _the_table;
83
84 // Set if one bucket is out of balance due to hash algorithm deficiency
85 static bool _needs_rehashing;
86
87 // For statistics
88 static int _symbols_removed;
89 static int _symbols_counted;
90
91 Symbol* allocate_symbol(const u1* name, int len, bool c_heap, TRAPS); // Assumes no characters larger than 0x7F
92
93 // Adding elements
94 Symbol* basic_add(int index, u1* name, int len, unsigned int hashValue,
95 bool c_heap, TRAPS);
96 bool basic_add(ClassLoaderData* loader_data,
97 constantPoolHandle cp, int names_count,
98 const char** names, int* lengths, int* cp_indices,
99 unsigned int* hashValues, TRAPS);
100
101 static void new_symbols(ClassLoaderData* loader_data,
102 constantPoolHandle cp, int names_count,
103 const char** name, int* lengths,
104 int* cp_indices, unsigned int* hashValues,
105 TRAPS) {
106 add(loader_data, cp, names_count, name, lengths, cp_indices, hashValues, THREAD);
107 }
108
109 Symbol* lookup(int index, const char* name, int len, unsigned int hash);
110
111 SymbolTable()
112 : RehashableHashtable<Symbol*, mtSymbol>(SymbolTableSize, sizeof (HashtableEntry<Symbol*, mtSymbol>)) {}
113
114 SymbolTable(HashtableBucket<mtSymbol>* t, int number_of_entries)
115 : RehashableHashtable<Symbol*, mtSymbol>(SymbolTableSize, sizeof (HashtableEntry<Symbol*, mtSymbol>), t,
116 number_of_entries) {}
117
118 // Arena for permanent symbols (null class loader) that are never unloaded
119 static Arena* _arena;
120 static Arena* arena() { return _arena; } // called for statistics
121
122 static void initialize_symbols(int arena_alloc_size = 0);
123
124 static volatile int _parallel_claimed_idx;
125
126 // Release any dead symbols
127 static void buckets_unlink(int start_idx, int end_idx, int* processed, int* removed, size_t* memory_total);
128 public:
129 enum {
130 symbol_alloc_batch_size = 8,
131 // Pick initial size based on java -version size measurements
132 symbol_alloc_arena_size = 360*K
133 };
134
135 // The symbol table
136 static SymbolTable* the_table() { return _the_table; }
137
138 // Size of one bucket in the string table. Used when checking for rollover.
139 static uint bucket_size() { return sizeof(HashtableBucket<mtSymbol>); }
140
141 static void create_table() {
142 assert(_the_table == NULL, "One symbol table allowed.");
143 _the_table = new SymbolTable();
144 initialize_symbols(symbol_alloc_arena_size);
145 }
146
147 static void create_table(HashtableBucket<mtSymbol>* t, int length,
148 int number_of_entries) {
149 assert(_the_table == NULL, "One symbol table allowed.");
150
151 // If CDS archive used a different symbol table size, use that size instead
152 // which is better than giving an error.
153 SymbolTableSize = length/bucket_size();
154
155 _the_table = new SymbolTable(t, number_of_entries);
156 // if CDS give symbol table a default arena size since most symbols
157 // are already allocated in the shared misc section.
158 initialize_symbols();
159 }
160
161 static unsigned int hash_symbol(const char* s, int len);
162
163 static Symbol* lookup(const char* name, int len, TRAPS);
164 // lookup only, won't add. Also calculate hash.
165 static Symbol* lookup_only(const char* name, int len, unsigned int& hash);
166 // Only copy to C string to be added if lookup failed.
167 static Symbol* lookup(const Symbol* sym, int begin, int end, TRAPS);
168
169 static void release(Symbol* sym);
170
171 // Look up the address of the literal in the SymbolTable for this Symbol*
172 static Symbol** lookup_symbol_addr(Symbol* sym);
173
174 // jchar (utf16) version of lookups
175 static Symbol* lookup_unicode(const jchar* name, int len, TRAPS);
176 static Symbol* lookup_only_unicode(const jchar* name, int len, unsigned int& hash);
177
178 static void add(ClassLoaderData* loader_data,
179 constantPoolHandle cp, int names_count,
180 const char** names, int* lengths, int* cp_indices,
213 static Symbol* lookup(int index, const char* name, int len, TRAPS);
214
215 // Needed for preloading classes in signatures when compiling.
216 // Returns the symbol is already present in symbol table, otherwise
217 // NULL. NO ALLOCATION IS GUARANTEED!
218 static Symbol* probe(const char* name, int len) {
219 unsigned int ignore_hash;
220 return lookup_only(name, len, ignore_hash);
221 }
222 static Symbol* probe_unicode(const jchar* name, int len) {
223 unsigned int ignore_hash;
224 return lookup_only_unicode(name, len, ignore_hash);
225 }
226
227 // Histogram
228 static void print_histogram() PRODUCT_RETURN;
229 static void print() PRODUCT_RETURN;
230
231 // Debugging
232 static void verify();
233 static void dump(outputStream* st);
234
235 // Sharing
236 static void copy_buckets(char** top, char*end) {
237 the_table()->Hashtable<Symbol*, mtSymbol>::copy_buckets(top, end);
238 }
239 static void copy_table(char** top, char*end) {
240 the_table()->Hashtable<Symbol*, mtSymbol>::copy_table(top, end);
241 }
242 static void reverse(void* boundary = NULL) {
243 the_table()->Hashtable<Symbol*, mtSymbol>::reverse(boundary);
244 }
245
246 // Rehash the symbol table if it gets out of balance
247 static void rehash_table();
248 static bool needs_rehashing() { return _needs_rehashing; }
249 // Parallel chunked scanning
250 static void clear_parallel_claimed_index() { _parallel_claimed_idx = 0; }
251 static int parallel_claimed_index() { return _parallel_claimed_idx; }
252 };
253
254 #endif // SHARE_VM_CLASSFILE_SYMBOLTABLE_HPP
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56
57 // Operator= increments reference count.
58 void operator=(const TempNewSymbol &s) {
59 //clear(); //FIXME
60 _temp = s._temp;
61 if (_temp !=NULL) _temp->increment_refcount();
62 }
63
64 // Decrement reference counter so it can go away if it's unique
65 void clear() { if (_temp != NULL) _temp->decrement_refcount(); _temp = NULL; }
66
67 ~TempNewSymbol() { clear(); }
68
69 // Operators so they can be used like Symbols
70 Symbol* operator -> () const { return _temp; }
71 bool operator == (Symbol* o) const { return _temp == o; }
72 // Sneaky conversion function
73 operator Symbol*() { return _temp; }
74 };
75
76 template <class T, class N> class CompactHashtable;
77
78 class SymbolTable : public RehashableHashtable<Symbol*, mtSymbol> {
79 friend class VMStructs;
80 friend class ClassFileParser;
81
82 private:
83 // The symbol table
84 static SymbolTable* _the_table;
85
86 // Set if one bucket is out of balance due to hash algorithm deficiency
87 static bool _needs_rehashing;
88 static bool _lookup_shared_first;
89
90 // For statistics
91 static int _symbols_removed;
92 static int _symbols_counted;
93
94 // shared symbol table.
95 static CompactHashtable<Symbol*, char> _shared_table;
96
97 Symbol* allocate_symbol(const u1* name, int len, bool c_heap, TRAPS); // Assumes no characters larger than 0x7F
98
99 // Adding elements
100 Symbol* basic_add(int index, u1* name, int len, unsigned int hashValue,
101 bool c_heap, TRAPS);
102 bool basic_add(ClassLoaderData* loader_data,
103 constantPoolHandle cp, int names_count,
104 const char** names, int* lengths, int* cp_indices,
105 unsigned int* hashValues, TRAPS);
106
107 static void new_symbols(ClassLoaderData* loader_data,
108 constantPoolHandle cp, int names_count,
109 const char** name, int* lengths,
110 int* cp_indices, unsigned int* hashValues,
111 TRAPS) {
112 add(loader_data, cp, names_count, name, lengths, cp_indices, hashValues, THREAD);
113 }
114
115 static Symbol* lookup_shared(const char* name, int len, unsigned int hash);
116 Symbol* lookup_dynamic(int index, const char* name, int len, unsigned int hash);
117 Symbol* lookup(int index, const char* name, int len, unsigned int hash);
118
119 SymbolTable()
120 : RehashableHashtable<Symbol*, mtSymbol>(SymbolTableSize, sizeof (HashtableEntry<Symbol*, mtSymbol>)) {}
121
122 SymbolTable(HashtableBucket<mtSymbol>* t, int number_of_entries)
123 : RehashableHashtable<Symbol*, mtSymbol>(SymbolTableSize, sizeof (HashtableEntry<Symbol*, mtSymbol>), t,
124 number_of_entries) {}
125
126 // Arena for permanent symbols (null class loader) that are never unloaded
127 static Arena* _arena;
128 static Arena* arena() { return _arena; } // called for statistics
129
130 static void initialize_symbols(int arena_alloc_size = 0);
131
132 static volatile int _parallel_claimed_idx;
133
134 // Release any dead symbols
135 static void buckets_unlink(int start_idx, int end_idx, int* processed, int* removed, size_t* memory_total);
136 public:
137 enum {
138 symbol_alloc_batch_size = 8,
139 // Pick initial size based on java -version size measurements
140 symbol_alloc_arena_size = 360*K
141 };
142
143 // The symbol table
144 static SymbolTable* the_table() { return _the_table; }
145
146 // Size of one bucket in the string table. Used when checking for rollover.
147 static uint bucket_size() { return sizeof(HashtableBucket<mtSymbol>); }
148
149 static void create_table() {
150 assert(_the_table == NULL, "One symbol table allowed.");
151 _the_table = new SymbolTable();
152 initialize_symbols(symbol_alloc_arena_size);
153 }
154
155 static unsigned int hash_symbol(const char* s, int len);
156
157 static Symbol* lookup(const char* name, int len, TRAPS);
158 // lookup only, won't add. Also calculate hash.
159 static Symbol* lookup_only(const char* name, int len, unsigned int& hash);
160 // Only copy to C string to be added if lookup failed.
161 static Symbol* lookup(const Symbol* sym, int begin, int end, TRAPS);
162
163 static void release(Symbol* sym);
164
165 // Look up the address of the literal in the SymbolTable for this Symbol*
166 static Symbol** lookup_symbol_addr(Symbol* sym);
167
168 // jchar (utf16) version of lookups
169 static Symbol* lookup_unicode(const jchar* name, int len, TRAPS);
170 static Symbol* lookup_only_unicode(const jchar* name, int len, unsigned int& hash);
171
172 static void add(ClassLoaderData* loader_data,
173 constantPoolHandle cp, int names_count,
174 const char** names, int* lengths, int* cp_indices,
207 static Symbol* lookup(int index, const char* name, int len, TRAPS);
208
209 // Needed for preloading classes in signatures when compiling.
210 // Returns the symbol is already present in symbol table, otherwise
211 // NULL. NO ALLOCATION IS GUARANTEED!
212 static Symbol* probe(const char* name, int len) {
213 unsigned int ignore_hash;
214 return lookup_only(name, len, ignore_hash);
215 }
216 static Symbol* probe_unicode(const jchar* name, int len) {
217 unsigned int ignore_hash;
218 return lookup_only_unicode(name, len, ignore_hash);
219 }
220
221 // Histogram
222 static void print_histogram() PRODUCT_RETURN;
223 static void print() PRODUCT_RETURN;
224
225 // Debugging
226 static void verify();
227 static void dump(outputStream* st, bool verbose=false);
228 static void read(const char* filename, TRAPS);
229
230 // Sharing
231 static bool copy_compact_table(char** top, char* end);
232 static const char* init_shared_table(const char* buffer);
233
234 // Rehash the symbol table if it gets out of balance
235 static void rehash_table();
236 static bool needs_rehashing() { return _needs_rehashing; }
237 // Parallel chunked scanning
238 static void clear_parallel_claimed_index() { _parallel_claimed_idx = 0; }
239 static int parallel_claimed_index() { return _parallel_claimed_idx; }
240 };
241
242 #endif // SHARE_VM_CLASSFILE_SYMBOLTABLE_HPP
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