src/share/vm/oops/constantPoolOop.hpp

Thu, 13 Mar 2008 14:17:48 -0700

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dcubed
date
Thu, 13 Mar 2008 14:17:48 -0700
changeset 487
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duke@435 1 /*
duke@435 2 * Copyright 1997-2007 Sun Microsystems, Inc. All Rights Reserved.
duke@435 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435 4 *
duke@435 5 * This code is free software; you can redistribute it and/or modify it
duke@435 6 * under the terms of the GNU General Public License version 2 only, as
duke@435 7 * published by the Free Software Foundation.
duke@435 8 *
duke@435 9 * This code is distributed in the hope that it will be useful, but WITHOUT
duke@435 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
duke@435 12 * version 2 for more details (a copy is included in the LICENSE file that
duke@435 13 * accompanied this code).
duke@435 14 *
duke@435 15 * You should have received a copy of the GNU General Public License version
duke@435 16 * 2 along with this work; if not, write to the Free Software Foundation,
duke@435 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435 18 *
duke@435 19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
duke@435 20 * CA 95054 USA or visit www.sun.com if you need additional information or
duke@435 21 * have any questions.
duke@435 22 *
duke@435 23 */
duke@435 24
duke@435 25 // A constantPool is an array containing class constants as described in the
duke@435 26 // class file.
duke@435 27 //
duke@435 28 // Most of the constant pool entries are written during class parsing, which
duke@435 29 // is safe. For klass and string types, the constant pool entry is
duke@435 30 // modified when the entry is resolved. If a klass or string constant pool
duke@435 31 // entry is read without a lock, only the resolved state guarantees that
duke@435 32 // the entry in the constant pool is a klass or String object and
duke@435 33 // not a symbolOop.
duke@435 34
duke@435 35 class SymbolHashMap;
duke@435 36
duke@435 37 class constantPoolOopDesc : public arrayOopDesc {
duke@435 38 friend class VMStructs;
duke@435 39 friend class BytecodeInterpreter; // Directly extracts an oop in the pool for fast instanceof/checkcast
duke@435 40 private:
duke@435 41 typeArrayOop _tags; // the tag array describing the constant pool's contents
duke@435 42 constantPoolCacheOop _cache; // the cache holding interpreter runtime information
duke@435 43 klassOop _pool_holder; // the corresponding class
duke@435 44 // only set to non-zero if constant pool is merged by RedefineClasses
duke@435 45 int _orig_length;
duke@435 46
duke@435 47 void set_tags(typeArrayOop tags) { oop_store_without_check((oop*)&_tags, tags); }
duke@435 48 void tag_at_put(int which, jbyte t) { tags()->byte_at_put(which, t); }
duke@435 49 void release_tag_at_put(int which, jbyte t) { tags()->release_byte_at_put(which, t); }
duke@435 50
duke@435 51 private:
duke@435 52 intptr_t* base() const { return (intptr_t*) (((char*) this) + sizeof(constantPoolOopDesc)); }
duke@435 53 oop* tags_addr() { return (oop*)&_tags; }
duke@435 54 oop* cache_addr() { return (oop*)&_cache; }
duke@435 55
duke@435 56 oop* obj_at_addr(int which) const {
duke@435 57 assert(is_within_bounds(which), "index out of bounds");
duke@435 58 return (oop*) &base()[which];
duke@435 59 }
duke@435 60
duke@435 61 jint* int_at_addr(int which) const {
duke@435 62 assert(is_within_bounds(which), "index out of bounds");
duke@435 63 return (jint*) &base()[which];
duke@435 64 }
duke@435 65
duke@435 66 jlong* long_at_addr(int which) const {
duke@435 67 assert(is_within_bounds(which), "index out of bounds");
duke@435 68 return (jlong*) &base()[which];
duke@435 69 }
duke@435 70
duke@435 71 jfloat* float_at_addr(int which) const {
duke@435 72 assert(is_within_bounds(which), "index out of bounds");
duke@435 73 return (jfloat*) &base()[which];
duke@435 74 }
duke@435 75
duke@435 76 jdouble* double_at_addr(int which) const {
duke@435 77 assert(is_within_bounds(which), "index out of bounds");
duke@435 78 return (jdouble*) &base()[which];
duke@435 79 }
duke@435 80
duke@435 81 public:
duke@435 82 typeArrayOop tags() const { return _tags; }
duke@435 83
duke@435 84 // Klass holding pool
duke@435 85 klassOop pool_holder() const { return _pool_holder; }
duke@435 86 void set_pool_holder(klassOop k) { oop_store_without_check((oop*)&_pool_holder, (oop) k); }
duke@435 87 oop* pool_holder_addr() { return (oop*)&_pool_holder; }
duke@435 88
duke@435 89 // Interpreter runtime support
duke@435 90 constantPoolCacheOop cache() const { return _cache; }
duke@435 91 void set_cache(constantPoolCacheOop cache){ oop_store((oop*)&_cache, cache); }
duke@435 92
duke@435 93 // Assembly code support
duke@435 94 static int tags_offset_in_bytes() { return offset_of(constantPoolOopDesc, _tags); }
duke@435 95 static int cache_offset_in_bytes() { return offset_of(constantPoolOopDesc, _cache); }
duke@435 96 static int pool_holder_offset_in_bytes() { return offset_of(constantPoolOopDesc, _pool_holder); }
duke@435 97
duke@435 98 // Storing constants
duke@435 99
duke@435 100 void klass_at_put(int which, klassOop k) {
duke@435 101 oop_store_without_check((volatile oop *)obj_at_addr(which), oop(k));
duke@435 102 // The interpreter assumes when the tag is stored, the klass is resolved
duke@435 103 // and the klassOop is a klass rather than a symbolOop, so we need
duke@435 104 // hardware store ordering here.
duke@435 105 release_tag_at_put(which, JVM_CONSTANT_Class);
duke@435 106 if (UseConcMarkSweepGC) {
duke@435 107 // In case the earlier card-mark was consumed by a concurrent
duke@435 108 // marking thread before the tag was updated, redirty the card.
duke@435 109 oop_store_without_check((volatile oop *)obj_at_addr(which), oop(k));
duke@435 110 }
duke@435 111 }
duke@435 112
duke@435 113 // For temporary use while constructing constant pool
duke@435 114 void klass_index_at_put(int which, int name_index) {
duke@435 115 tag_at_put(which, JVM_CONSTANT_ClassIndex);
duke@435 116 *int_at_addr(which) = name_index;
duke@435 117 }
duke@435 118
duke@435 119 // Temporary until actual use
duke@435 120 void unresolved_klass_at_put(int which, symbolOop s) {
duke@435 121 // Overwrite the old index with a GC friendly value so
duke@435 122 // that if GC looks during the transition it won't try
duke@435 123 // to treat a small integer as oop.
duke@435 124 *obj_at_addr(which) = NULL;
duke@435 125 release_tag_at_put(which, JVM_CONSTANT_UnresolvedClass);
duke@435 126 oop_store_without_check(obj_at_addr(which), oop(s));
duke@435 127 }
duke@435 128
duke@435 129 // Temporary until actual use
duke@435 130 void unresolved_string_at_put(int which, symbolOop s) {
duke@435 131 *obj_at_addr(which) = NULL;
duke@435 132 release_tag_at_put(which, JVM_CONSTANT_UnresolvedString);
duke@435 133 oop_store_without_check(obj_at_addr(which), oop(s));
duke@435 134 }
duke@435 135
duke@435 136 void int_at_put(int which, jint i) {
duke@435 137 tag_at_put(which, JVM_CONSTANT_Integer);
duke@435 138 *int_at_addr(which) = i;
duke@435 139 }
duke@435 140
duke@435 141 void long_at_put(int which, jlong l) {
duke@435 142 tag_at_put(which, JVM_CONSTANT_Long);
duke@435 143 // *long_at_addr(which) = l;
duke@435 144 Bytes::put_native_u8((address)long_at_addr(which), *((u8*) &l));
duke@435 145 }
duke@435 146
duke@435 147 void float_at_put(int which, jfloat f) {
duke@435 148 tag_at_put(which, JVM_CONSTANT_Float);
duke@435 149 *float_at_addr(which) = f;
duke@435 150 }
duke@435 151
duke@435 152 void double_at_put(int which, jdouble d) {
duke@435 153 tag_at_put(which, JVM_CONSTANT_Double);
duke@435 154 // *double_at_addr(which) = d;
duke@435 155 // u8 temp = *(u8*) &d;
duke@435 156 Bytes::put_native_u8((address) double_at_addr(which), *((u8*) &d));
duke@435 157 }
duke@435 158
duke@435 159 void symbol_at_put(int which, symbolOop s) {
duke@435 160 tag_at_put(which, JVM_CONSTANT_Utf8);
duke@435 161 oop_store_without_check(obj_at_addr(which), oop(s));
duke@435 162 }
duke@435 163
duke@435 164 void string_at_put(int which, oop str) {
duke@435 165 oop_store((volatile oop*)obj_at_addr(which), str);
duke@435 166 release_tag_at_put(which, JVM_CONSTANT_String);
duke@435 167 if (UseConcMarkSweepGC) {
duke@435 168 // In case the earlier card-mark was consumed by a concurrent
duke@435 169 // marking thread before the tag was updated, redirty the card.
duke@435 170 oop_store_without_check((volatile oop *)obj_at_addr(which), str);
duke@435 171 }
duke@435 172 }
duke@435 173
duke@435 174 // For temporary use while constructing constant pool
duke@435 175 void string_index_at_put(int which, int string_index) {
duke@435 176 tag_at_put(which, JVM_CONSTANT_StringIndex);
duke@435 177 *int_at_addr(which) = string_index;
duke@435 178 }
duke@435 179
duke@435 180 void field_at_put(int which, int class_index, int name_and_type_index) {
duke@435 181 tag_at_put(which, JVM_CONSTANT_Fieldref);
duke@435 182 *int_at_addr(which) = ((jint) name_and_type_index<<16) | class_index;
duke@435 183 }
duke@435 184
duke@435 185 void method_at_put(int which, int class_index, int name_and_type_index) {
duke@435 186 tag_at_put(which, JVM_CONSTANT_Methodref);
duke@435 187 *int_at_addr(which) = ((jint) name_and_type_index<<16) | class_index;
duke@435 188 }
duke@435 189
duke@435 190 void interface_method_at_put(int which, int class_index, int name_and_type_index) {
duke@435 191 tag_at_put(which, JVM_CONSTANT_InterfaceMethodref);
duke@435 192 *int_at_addr(which) = ((jint) name_and_type_index<<16) | class_index; // Not so nice
duke@435 193 }
duke@435 194
duke@435 195 void name_and_type_at_put(int which, int name_index, int signature_index) {
duke@435 196 tag_at_put(which, JVM_CONSTANT_NameAndType);
duke@435 197 *int_at_addr(which) = ((jint) signature_index<<16) | name_index; // Not so nice
duke@435 198 }
duke@435 199
duke@435 200 // Tag query
duke@435 201
duke@435 202 constantTag tag_at(int which) const { return (constantTag)tags()->byte_at_acquire(which); }
duke@435 203
duke@435 204 // Whether the entry is a pointer that must be GC'd.
duke@435 205 bool is_pointer_entry(int which) {
duke@435 206 constantTag tag = tag_at(which);
duke@435 207 return tag.is_klass() ||
duke@435 208 tag.is_unresolved_klass() ||
duke@435 209 tag.is_symbol() ||
duke@435 210 tag.is_unresolved_string() ||
duke@435 211 tag.is_string();
duke@435 212 }
duke@435 213
duke@435 214 // Fetching constants
duke@435 215
duke@435 216 klassOop klass_at(int which, TRAPS) {
duke@435 217 constantPoolHandle h_this(THREAD, this);
duke@435 218 return klass_at_impl(h_this, which, CHECK_NULL);
duke@435 219 }
duke@435 220
duke@435 221 symbolOop klass_name_at(int which); // Returns the name, w/o resolving.
duke@435 222
duke@435 223 klassOop resolved_klass_at(int which) { // Used by Compiler
duke@435 224 guarantee(tag_at(which).is_klass(), "Corrupted constant pool");
duke@435 225 // Must do an acquire here in case another thread resolved the klass
duke@435 226 // behind our back, lest we later load stale values thru the oop.
duke@435 227 return klassOop((oop)OrderAccess::load_ptr_acquire(obj_at_addr(which)));
duke@435 228 }
duke@435 229
duke@435 230 // This method should only be used with a cpool lock or during parsing or gc
duke@435 231 symbolOop unresolved_klass_at(int which) { // Temporary until actual use
duke@435 232 symbolOop s = symbolOop((oop)OrderAccess::load_ptr_acquire(obj_at_addr(which)));
duke@435 233 // check that the klass is still unresolved.
duke@435 234 assert(tag_at(which).is_unresolved_klass(), "Corrupted constant pool");
duke@435 235 return s;
duke@435 236 }
duke@435 237
duke@435 238 // RedefineClasses() API support:
duke@435 239 symbolOop klass_at_noresolve(int which) { return klass_name_at(which); }
duke@435 240
duke@435 241 jint int_at(int which) {
duke@435 242 assert(tag_at(which).is_int(), "Corrupted constant pool");
duke@435 243 return *int_at_addr(which);
duke@435 244 }
duke@435 245
duke@435 246 jlong long_at(int which) {
duke@435 247 assert(tag_at(which).is_long(), "Corrupted constant pool");
duke@435 248 // return *long_at_addr(which);
duke@435 249 u8 tmp = Bytes::get_native_u8((address)&base()[which]);
duke@435 250 return *((jlong*)&tmp);
duke@435 251 }
duke@435 252
duke@435 253 jfloat float_at(int which) {
duke@435 254 assert(tag_at(which).is_float(), "Corrupted constant pool");
duke@435 255 return *float_at_addr(which);
duke@435 256 }
duke@435 257
duke@435 258 jdouble double_at(int which) {
duke@435 259 assert(tag_at(which).is_double(), "Corrupted constant pool");
duke@435 260 u8 tmp = Bytes::get_native_u8((address)&base()[which]);
duke@435 261 return *((jdouble*)&tmp);
duke@435 262 }
duke@435 263
duke@435 264 symbolOop symbol_at(int which) {
duke@435 265 assert(tag_at(which).is_utf8(), "Corrupted constant pool");
duke@435 266 return symbolOop(*obj_at_addr(which));
duke@435 267 }
duke@435 268
duke@435 269 oop string_at(int which, TRAPS) {
duke@435 270 constantPoolHandle h_this(THREAD, this);
duke@435 271 return string_at_impl(h_this, which, CHECK_NULL);
duke@435 272 }
duke@435 273
duke@435 274 // only called when we are sure a string entry is already resolved (via an
duke@435 275 // earlier string_at call.
duke@435 276 oop resolved_string_at(int which) {
duke@435 277 assert(tag_at(which).is_string(), "Corrupted constant pool");
duke@435 278 // Must do an acquire here in case another thread resolved the klass
duke@435 279 // behind our back, lest we later load stale values thru the oop.
duke@435 280 return (oop)OrderAccess::load_ptr_acquire(obj_at_addr(which));
duke@435 281 }
duke@435 282
duke@435 283 // This method should only be used with a cpool lock or during parsing or gc
duke@435 284 symbolOop unresolved_string_at(int which) { // Temporary until actual use
duke@435 285 symbolOop s = symbolOop((oop)OrderAccess::load_ptr_acquire(obj_at_addr(which)));
duke@435 286 // check that the string is still unresolved.
duke@435 287 assert(tag_at(which).is_unresolved_string(), "Corrupted constant pool");
duke@435 288 return s;
duke@435 289 }
duke@435 290
duke@435 291 // Returns an UTF8 for a CONSTANT_String entry at a given index.
duke@435 292 // UTF8 char* representation was chosen to avoid conversion of
duke@435 293 // java_lang_Strings at resolved entries into symbolOops
duke@435 294 // or vice versa.
duke@435 295 char* string_at_noresolve(int which);
duke@435 296
duke@435 297 jint name_and_type_at(int which) {
duke@435 298 assert(tag_at(which).is_name_and_type(), "Corrupted constant pool");
duke@435 299 return *int_at_addr(which);
duke@435 300 }
duke@435 301
duke@435 302 // The following methods (klass_ref_at, klass_ref_at_noresolve, name_ref_at,
duke@435 303 // signature_ref_at, klass_ref_index_at, name_and_type_ref_index_at,
duke@435 304 // name_ref_index_at, signature_ref_index_at) all expect constant pool indices
duke@435 305 // from the bytecodes to be passed in, which are actually potentially byte-swapped
duke@435 306 // contstant pool cache indices. See field_or_method_at.
duke@435 307
duke@435 308 // Lookup for entries consisting of (klass_index, name_and_type index)
duke@435 309 klassOop klass_ref_at(int which, TRAPS);
duke@435 310 symbolOop klass_ref_at_noresolve(int which);
duke@435 311 symbolOop name_ref_at(int which);
duke@435 312 symbolOop signature_ref_at(int which); // the type descriptor
duke@435 313
duke@435 314 int klass_ref_index_at(int which);
duke@435 315 int name_and_type_ref_index_at(int which);
duke@435 316
duke@435 317 // Lookup for entries consisting of (name_index, signature_index)
duke@435 318 int name_ref_index_at(int which);
duke@435 319 int signature_ref_index_at(int which);
duke@435 320
duke@435 321 BasicType basic_type_for_signature_at(int which);
duke@435 322
duke@435 323 // Resolve string constants (to prevent allocation during compilation)
duke@435 324 void resolve_string_constants(TRAPS) {
duke@435 325 constantPoolHandle h_this(THREAD, this);
duke@435 326 resolve_string_constants_impl(h_this, CHECK);
duke@435 327 }
duke@435 328
duke@435 329 // Klass name matches name at offset
duke@435 330 bool klass_name_at_matches(instanceKlassHandle k, int which);
duke@435 331
duke@435 332 // Sizing
duke@435 333 static int header_size() { return sizeof(constantPoolOopDesc)/HeapWordSize; }
duke@435 334 static int object_size(int length) { return align_object_size(header_size() + length); }
duke@435 335 int object_size() { return object_size(length()); }
duke@435 336
duke@435 337 friend class constantPoolKlass;
duke@435 338 friend class ClassFileParser;
duke@435 339 friend class SystemDictionary;
duke@435 340
duke@435 341 // Used by compiler to prevent classloading.
duke@435 342 static klassOop klass_at_if_loaded (constantPoolHandle this_oop, int which);
duke@435 343 static klassOop klass_ref_at_if_loaded (constantPoolHandle this_oop, int which);
duke@435 344 // Same as above - but does LinkResolving.
duke@435 345 static klassOop klass_ref_at_if_loaded_check(constantPoolHandle this_oop, int which, TRAPS);
duke@435 346
duke@435 347 // Routines currently used for annotations (only called by jvm.cpp) but which might be used in the
duke@435 348 // future by other Java code. These take constant pool indices rather than possibly-byte-swapped
duke@435 349 // constant pool cache indices as do the peer methods above.
duke@435 350 symbolOop uncached_name_ref_at(int which);
duke@435 351 symbolOop uncached_signature_ref_at(int which);
duke@435 352 int uncached_klass_ref_index_at(int which);
duke@435 353 int uncached_name_and_type_ref_index_at(int which);
duke@435 354
duke@435 355 // Sharing
duke@435 356 int pre_resolve_shared_klasses(TRAPS);
duke@435 357 void shared_symbols_iterate(OopClosure* closure0);
duke@435 358 void shared_tags_iterate(OopClosure* closure0);
duke@435 359 void shared_strings_iterate(OopClosure* closure0);
duke@435 360
duke@435 361 // Debugging
duke@435 362 const char* printable_name_at(int which) PRODUCT_RETURN0;
duke@435 363
duke@435 364 private:
duke@435 365
duke@435 366 // Takes either a constant pool cache index in possibly byte-swapped
duke@435 367 // byte order (which comes from the bytecodes after rewriting) or,
duke@435 368 // if "uncached" is true, a vanilla constant pool index
duke@435 369 jint field_or_method_at(int which, bool uncached) {
duke@435 370 int i = -1;
duke@435 371 if (uncached || cache() == NULL) {
duke@435 372 i = which;
duke@435 373 } else {
duke@435 374 // change byte-ordering and go via cache
duke@435 375 i = cache()->entry_at(Bytes::swap_u2(which))->constant_pool_index();
duke@435 376 }
duke@435 377 assert(tag_at(i).is_field_or_method(), "Corrupted constant pool");
duke@435 378 return *int_at_addr(i);
duke@435 379 }
duke@435 380
duke@435 381 // Used while constructing constant pool (only by ClassFileParser)
duke@435 382 jint klass_index_at(int which) {
duke@435 383 assert(tag_at(which).is_klass_index(), "Corrupted constant pool");
duke@435 384 return *int_at_addr(which);
duke@435 385 }
duke@435 386
duke@435 387 jint string_index_at(int which) {
duke@435 388 assert(tag_at(which).is_string_index(), "Corrupted constant pool");
duke@435 389 return *int_at_addr(which);
duke@435 390 }
duke@435 391
duke@435 392 // Performs the LinkResolver checks
duke@435 393 static void verify_constant_pool_resolve(constantPoolHandle this_oop, KlassHandle klass, TRAPS);
duke@435 394
duke@435 395 // Implementation of methods that needs an exposed 'this' pointer, in order to
duke@435 396 // handle GC while executing the method
duke@435 397 static klassOop klass_at_impl(constantPoolHandle this_oop, int which, TRAPS);
duke@435 398 static oop string_at_impl(constantPoolHandle this_oop, int which, TRAPS);
duke@435 399
duke@435 400 // Resolve string constants (to prevent allocation during compilation)
duke@435 401 static void resolve_string_constants_impl(constantPoolHandle this_oop, TRAPS);
duke@435 402
duke@435 403 public:
duke@435 404 // Merging constantPoolOop support:
duke@435 405 bool compare_entry_to(int index1, constantPoolHandle cp2, int index2, TRAPS);
duke@435 406 void copy_cp_to(int start_i, int end_i, constantPoolHandle to_cp, int to_i,
duke@435 407 TRAPS);
duke@435 408 void copy_entry_to(int from_i, constantPoolHandle to_cp, int to_i, TRAPS);
duke@435 409 int find_matching_entry(int pattern_i, constantPoolHandle search_cp, TRAPS);
duke@435 410 int orig_length() const { return _orig_length; }
duke@435 411 void set_orig_length(int orig_length) { _orig_length = orig_length; }
duke@435 412
duke@435 413
duke@435 414 // JVMTI accesss - GetConstantPool, RetransformClasses, ...
duke@435 415 friend class JvmtiConstantPoolReconstituter;
duke@435 416
duke@435 417 private:
duke@435 418 jint cpool_entry_size(jint idx);
duke@435 419 jint hash_entries_to(SymbolHashMap *symmap, SymbolHashMap *classmap);
duke@435 420
duke@435 421 // Copy cpool bytes into byte array.
duke@435 422 // Returns:
duke@435 423 // int > 0, count of the raw cpool bytes that have been copied
duke@435 424 // 0, OutOfMemory error
duke@435 425 // -1, Internal error
duke@435 426 int copy_cpool_bytes(int cpool_size,
duke@435 427 SymbolHashMap* tbl,
duke@435 428 unsigned char *bytes);
duke@435 429 };
duke@435 430
duke@435 431 class SymbolHashMapEntry : public CHeapObj {
duke@435 432 private:
duke@435 433 unsigned int _hash; // 32-bit hash for item
duke@435 434 SymbolHashMapEntry* _next; // Next element in the linked list for this bucket
duke@435 435 symbolOop _symbol; // 1-st part of the mapping: symbol => value
duke@435 436 u2 _value; // 2-nd part of the mapping: symbol => value
duke@435 437
duke@435 438 public:
duke@435 439 unsigned int hash() const { return _hash; }
duke@435 440 void set_hash(unsigned int hash) { _hash = hash; }
duke@435 441
duke@435 442 SymbolHashMapEntry* next() const { return _next; }
duke@435 443 void set_next(SymbolHashMapEntry* next) { _next = next; }
duke@435 444
duke@435 445 symbolOop symbol() const { return _symbol; }
duke@435 446 void set_symbol(symbolOop sym) { _symbol = sym; }
duke@435 447
duke@435 448 u2 value() const { return _value; }
duke@435 449 void set_value(u2 value) { _value = value; }
duke@435 450
duke@435 451 SymbolHashMapEntry(unsigned int hash, symbolOop symbol, u2 value)
duke@435 452 : _hash(hash), _symbol(symbol), _value(value), _next(NULL) {}
duke@435 453
duke@435 454 }; // End SymbolHashMapEntry class
duke@435 455
duke@435 456
duke@435 457 class SymbolHashMapBucket : public CHeapObj {
duke@435 458
duke@435 459 private:
duke@435 460 SymbolHashMapEntry* _entry;
duke@435 461
duke@435 462 public:
duke@435 463 SymbolHashMapEntry* entry() const { return _entry; }
duke@435 464 void set_entry(SymbolHashMapEntry* entry) { _entry = entry; }
duke@435 465 void clear() { _entry = NULL; }
duke@435 466
duke@435 467 }; // End SymbolHashMapBucket class
duke@435 468
duke@435 469
duke@435 470 class SymbolHashMap: public CHeapObj {
duke@435 471
duke@435 472 private:
duke@435 473 // Default number of entries in the table
duke@435 474 enum SymbolHashMap_Constants {
duke@435 475 _Def_HashMap_Size = 256
duke@435 476 };
duke@435 477
duke@435 478 int _table_size;
duke@435 479 SymbolHashMapBucket* _buckets;
duke@435 480
duke@435 481 void initialize_table(int table_size) {
duke@435 482 _table_size = table_size;
duke@435 483 _buckets = NEW_C_HEAP_ARRAY(SymbolHashMapBucket, table_size);
duke@435 484 for (int index = 0; index < table_size; index++) {
duke@435 485 _buckets[index].clear();
duke@435 486 }
duke@435 487 }
duke@435 488
duke@435 489 public:
duke@435 490
duke@435 491 int table_size() const { return _table_size; }
duke@435 492
duke@435 493 SymbolHashMap() { initialize_table(_Def_HashMap_Size); }
duke@435 494 SymbolHashMap(int table_size) { initialize_table(table_size); }
duke@435 495
duke@435 496 // hash P(31) from Kernighan & Ritchie
duke@435 497 static unsigned int compute_hash(const char* str, int len) {
duke@435 498 unsigned int hash = 0;
duke@435 499 while (len-- > 0) {
duke@435 500 hash = 31*hash + (unsigned) *str;
duke@435 501 str++;
duke@435 502 }
duke@435 503 return hash;
duke@435 504 }
duke@435 505
duke@435 506 SymbolHashMapEntry* bucket(int i) {
duke@435 507 return _buckets[i].entry();
duke@435 508 }
duke@435 509
duke@435 510 void add_entry(symbolOop sym, u2 value);
duke@435 511 SymbolHashMapEntry* find_entry(symbolOop sym);
duke@435 512
duke@435 513 u2 symbol_to_value(symbolOop sym) {
duke@435 514 SymbolHashMapEntry *entry = find_entry(sym);
duke@435 515 return (entry == NULL) ? 0 : entry->value();
duke@435 516 }
duke@435 517
duke@435 518 ~SymbolHashMap() {
duke@435 519 SymbolHashMapEntry* next;
duke@435 520 for (int i = 0; i < _table_size; i++) {
duke@435 521 for (SymbolHashMapEntry* cur = bucket(i); cur != NULL; cur = next) {
duke@435 522 next = cur->next();
duke@435 523 delete(cur);
duke@435 524 }
duke@435 525 }
duke@435 526 delete _buckets;
duke@435 527 }
duke@435 528 }; // End SymbolHashMap class

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