Mercurial > hg > graal-compiler
annotate src/share/vm/oops/constantPoolOop.hpp @ 113:ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
Summary: Compressed oops in instances, arrays, and headers. Code contributors are coleenp, phh, never, swamyv
Reviewed-by: jmasa, kamg, acorn, tbell, kvn, rasbold
| author | coleenp |
|---|---|
| date | Sun, 13 Apr 2008 17:43:42 -0400 |
| parents | a61af66fc99e |
| children | d1605aabd0a1 |
| rev | line source |
|---|---|
| 0 | 1 /* |
| 2 * Copyright 1997-2007 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 // A constantPool is an array containing class constants as described in the | |
| 26 // class file. | |
| 27 // | |
| 28 // Most of the constant pool entries are written during class parsing, which | |
| 29 // is safe. For klass and string types, the constant pool entry is | |
| 30 // modified when the entry is resolved. If a klass or string constant pool | |
| 31 // entry is read without a lock, only the resolved state guarantees that | |
| 32 // the entry in the constant pool is a klass or String object and | |
| 33 // not a symbolOop. | |
| 34 | |
| 35 class SymbolHashMap; | |
| 36 | |
|
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37 class constantPoolOopDesc : public oopDesc { |
| 0 | 38 friend class VMStructs; |
| 39 friend class BytecodeInterpreter; // Directly extracts an oop in the pool for fast instanceof/checkcast | |
| 40 private: | |
| 41 typeArrayOop _tags; // the tag array describing the constant pool's contents | |
| 42 constantPoolCacheOop _cache; // the cache holding interpreter runtime information | |
| 43 klassOop _pool_holder; // the corresponding class | |
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44 int _length; // number of elements in the array |
| 0 | 45 // only set to non-zero if constant pool is merged by RedefineClasses |
| 46 int _orig_length; | |
| 47 | |
| 48 void set_tags(typeArrayOop tags) { oop_store_without_check((oop*)&_tags, tags); } | |
| 49 void tag_at_put(int which, jbyte t) { tags()->byte_at_put(which, t); } | |
| 50 void release_tag_at_put(int which, jbyte t) { tags()->release_byte_at_put(which, t); } | |
| 51 | |
| 52 private: | |
| 53 intptr_t* base() const { return (intptr_t*) (((char*) this) + sizeof(constantPoolOopDesc)); } | |
| 54 oop* tags_addr() { return (oop*)&_tags; } | |
| 55 oop* cache_addr() { return (oop*)&_cache; } | |
| 56 | |
| 57 oop* obj_at_addr(int which) const { | |
| 58 assert(is_within_bounds(which), "index out of bounds"); | |
| 59 return (oop*) &base()[which]; | |
| 60 } | |
| 61 | |
| 62 jint* int_at_addr(int which) const { | |
| 63 assert(is_within_bounds(which), "index out of bounds"); | |
| 64 return (jint*) &base()[which]; | |
| 65 } | |
| 66 | |
| 67 jlong* long_at_addr(int which) const { | |
| 68 assert(is_within_bounds(which), "index out of bounds"); | |
| 69 return (jlong*) &base()[which]; | |
| 70 } | |
| 71 | |
| 72 jfloat* float_at_addr(int which) const { | |
| 73 assert(is_within_bounds(which), "index out of bounds"); | |
| 74 return (jfloat*) &base()[which]; | |
| 75 } | |
| 76 | |
| 77 jdouble* double_at_addr(int which) const { | |
| 78 assert(is_within_bounds(which), "index out of bounds"); | |
| 79 return (jdouble*) &base()[which]; | |
| 80 } | |
| 81 | |
| 82 public: | |
| 83 typeArrayOop tags() const { return _tags; } | |
| 84 | |
| 85 // Klass holding pool | |
| 86 klassOop pool_holder() const { return _pool_holder; } | |
| 87 void set_pool_holder(klassOop k) { oop_store_without_check((oop*)&_pool_holder, (oop) k); } | |
| 88 oop* pool_holder_addr() { return (oop*)&_pool_holder; } | |
| 89 | |
| 90 // Interpreter runtime support | |
| 91 constantPoolCacheOop cache() const { return _cache; } | |
| 92 void set_cache(constantPoolCacheOop cache){ oop_store((oop*)&_cache, cache); } | |
| 93 | |
| 94 // Assembly code support | |
| 95 static int tags_offset_in_bytes() { return offset_of(constantPoolOopDesc, _tags); } | |
| 96 static int cache_offset_in_bytes() { return offset_of(constantPoolOopDesc, _cache); } | |
| 97 static int pool_holder_offset_in_bytes() { return offset_of(constantPoolOopDesc, _pool_holder); } | |
| 98 | |
| 99 // Storing constants | |
| 100 | |
| 101 void klass_at_put(int which, klassOop k) { | |
| 102 oop_store_without_check((volatile oop *)obj_at_addr(which), oop(k)); | |
| 103 // The interpreter assumes when the tag is stored, the klass is resolved | |
| 104 // and the klassOop is a klass rather than a symbolOop, so we need | |
| 105 // hardware store ordering here. | |
| 106 release_tag_at_put(which, JVM_CONSTANT_Class); | |
| 107 if (UseConcMarkSweepGC) { | |
| 108 // In case the earlier card-mark was consumed by a concurrent | |
| 109 // marking thread before the tag was updated, redirty the card. | |
| 110 oop_store_without_check((volatile oop *)obj_at_addr(which), oop(k)); | |
| 111 } | |
| 112 } | |
| 113 | |
| 114 // For temporary use while constructing constant pool | |
| 115 void klass_index_at_put(int which, int name_index) { | |
| 116 tag_at_put(which, JVM_CONSTANT_ClassIndex); | |
| 117 *int_at_addr(which) = name_index; | |
| 118 } | |
| 119 | |
| 120 // Temporary until actual use | |
| 121 void unresolved_klass_at_put(int which, symbolOop s) { | |
| 122 // Overwrite the old index with a GC friendly value so | |
| 123 // that if GC looks during the transition it won't try | |
| 124 // to treat a small integer as oop. | |
| 125 *obj_at_addr(which) = NULL; | |
| 126 release_tag_at_put(which, JVM_CONSTANT_UnresolvedClass); | |
| 127 oop_store_without_check(obj_at_addr(which), oop(s)); | |
| 128 } | |
| 129 | |
| 130 // Temporary until actual use | |
| 131 void unresolved_string_at_put(int which, symbolOop s) { | |
| 132 *obj_at_addr(which) = NULL; | |
| 133 release_tag_at_put(which, JVM_CONSTANT_UnresolvedString); | |
| 134 oop_store_without_check(obj_at_addr(which), oop(s)); | |
| 135 } | |
| 136 | |
| 137 void int_at_put(int which, jint i) { | |
| 138 tag_at_put(which, JVM_CONSTANT_Integer); | |
| 139 *int_at_addr(which) = i; | |
| 140 } | |
| 141 | |
| 142 void long_at_put(int which, jlong l) { | |
| 143 tag_at_put(which, JVM_CONSTANT_Long); | |
| 144 // *long_at_addr(which) = l; | |
| 145 Bytes::put_native_u8((address)long_at_addr(which), *((u8*) &l)); | |
| 146 } | |
| 147 | |
| 148 void float_at_put(int which, jfloat f) { | |
| 149 tag_at_put(which, JVM_CONSTANT_Float); | |
| 150 *float_at_addr(which) = f; | |
| 151 } | |
| 152 | |
| 153 void double_at_put(int which, jdouble d) { | |
| 154 tag_at_put(which, JVM_CONSTANT_Double); | |
| 155 // *double_at_addr(which) = d; | |
| 156 // u8 temp = *(u8*) &d; | |
| 157 Bytes::put_native_u8((address) double_at_addr(which), *((u8*) &d)); | |
| 158 } | |
| 159 | |
| 160 void symbol_at_put(int which, symbolOop s) { | |
| 161 tag_at_put(which, JVM_CONSTANT_Utf8); | |
| 162 oop_store_without_check(obj_at_addr(which), oop(s)); | |
| 163 } | |
| 164 | |
| 165 void string_at_put(int which, oop str) { | |
| 166 oop_store((volatile oop*)obj_at_addr(which), str); | |
| 167 release_tag_at_put(which, JVM_CONSTANT_String); | |
| 168 if (UseConcMarkSweepGC) { | |
| 169 // In case the earlier card-mark was consumed by a concurrent | |
| 170 // marking thread before the tag was updated, redirty the card. | |
| 171 oop_store_without_check((volatile oop *)obj_at_addr(which), str); | |
| 172 } | |
| 173 } | |
| 174 | |
| 175 // For temporary use while constructing constant pool | |
| 176 void string_index_at_put(int which, int string_index) { | |
| 177 tag_at_put(which, JVM_CONSTANT_StringIndex); | |
| 178 *int_at_addr(which) = string_index; | |
| 179 } | |
| 180 | |
| 181 void field_at_put(int which, int class_index, int name_and_type_index) { | |
| 182 tag_at_put(which, JVM_CONSTANT_Fieldref); | |
| 183 *int_at_addr(which) = ((jint) name_and_type_index<<16) | class_index; | |
| 184 } | |
| 185 | |
| 186 void method_at_put(int which, int class_index, int name_and_type_index) { | |
| 187 tag_at_put(which, JVM_CONSTANT_Methodref); | |
| 188 *int_at_addr(which) = ((jint) name_and_type_index<<16) | class_index; | |
| 189 } | |
| 190 | |
| 191 void interface_method_at_put(int which, int class_index, int name_and_type_index) { | |
| 192 tag_at_put(which, JVM_CONSTANT_InterfaceMethodref); | |
| 193 *int_at_addr(which) = ((jint) name_and_type_index<<16) | class_index; // Not so nice | |
| 194 } | |
| 195 | |
| 196 void name_and_type_at_put(int which, int name_index, int signature_index) { | |
| 197 tag_at_put(which, JVM_CONSTANT_NameAndType); | |
| 198 *int_at_addr(which) = ((jint) signature_index<<16) | name_index; // Not so nice | |
| 199 } | |
| 200 | |
| 201 // Tag query | |
| 202 | |
| 203 constantTag tag_at(int which) const { return (constantTag)tags()->byte_at_acquire(which); } | |
| 204 | |
| 205 // Whether the entry is a pointer that must be GC'd. | |
| 206 bool is_pointer_entry(int which) { | |
| 207 constantTag tag = tag_at(which); | |
| 208 return tag.is_klass() || | |
| 209 tag.is_unresolved_klass() || | |
| 210 tag.is_symbol() || | |
| 211 tag.is_unresolved_string() || | |
| 212 tag.is_string(); | |
| 213 } | |
| 214 | |
| 215 // Fetching constants | |
| 216 | |
| 217 klassOop klass_at(int which, TRAPS) { | |
| 218 constantPoolHandle h_this(THREAD, this); | |
| 219 return klass_at_impl(h_this, which, CHECK_NULL); | |
| 220 } | |
| 221 | |
| 222 symbolOop klass_name_at(int which); // Returns the name, w/o resolving. | |
| 223 | |
| 224 klassOop resolved_klass_at(int which) { // Used by Compiler | |
| 225 guarantee(tag_at(which).is_klass(), "Corrupted constant pool"); | |
| 226 // Must do an acquire here in case another thread resolved the klass | |
| 227 // behind our back, lest we later load stale values thru the oop. | |
| 228 return klassOop((oop)OrderAccess::load_ptr_acquire(obj_at_addr(which))); | |
| 229 } | |
| 230 | |
| 231 // This method should only be used with a cpool lock or during parsing or gc | |
| 232 symbolOop unresolved_klass_at(int which) { // Temporary until actual use | |
| 233 symbolOop s = symbolOop((oop)OrderAccess::load_ptr_acquire(obj_at_addr(which))); | |
| 234 // check that the klass is still unresolved. | |
| 235 assert(tag_at(which).is_unresolved_klass(), "Corrupted constant pool"); | |
| 236 return s; | |
| 237 } | |
| 238 | |
| 239 // RedefineClasses() API support: | |
| 240 symbolOop klass_at_noresolve(int which) { return klass_name_at(which); } | |
| 241 | |
| 242 jint int_at(int which) { | |
| 243 assert(tag_at(which).is_int(), "Corrupted constant pool"); | |
| 244 return *int_at_addr(which); | |
| 245 } | |
| 246 | |
| 247 jlong long_at(int which) { | |
| 248 assert(tag_at(which).is_long(), "Corrupted constant pool"); | |
| 249 // return *long_at_addr(which); | |
| 250 u8 tmp = Bytes::get_native_u8((address)&base()[which]); | |
| 251 return *((jlong*)&tmp); | |
| 252 } | |
| 253 | |
| 254 jfloat float_at(int which) { | |
| 255 assert(tag_at(which).is_float(), "Corrupted constant pool"); | |
| 256 return *float_at_addr(which); | |
| 257 } | |
| 258 | |
| 259 jdouble double_at(int which) { | |
| 260 assert(tag_at(which).is_double(), "Corrupted constant pool"); | |
| 261 u8 tmp = Bytes::get_native_u8((address)&base()[which]); | |
| 262 return *((jdouble*)&tmp); | |
| 263 } | |
| 264 | |
| 265 symbolOop symbol_at(int which) { | |
| 266 assert(tag_at(which).is_utf8(), "Corrupted constant pool"); | |
| 267 return symbolOop(*obj_at_addr(which)); | |
| 268 } | |
| 269 | |
| 270 oop string_at(int which, TRAPS) { | |
| 271 constantPoolHandle h_this(THREAD, this); | |
| 272 return string_at_impl(h_this, which, CHECK_NULL); | |
| 273 } | |
| 274 | |
| 275 // only called when we are sure a string entry is already resolved (via an | |
| 276 // earlier string_at call. | |
| 277 oop resolved_string_at(int which) { | |
| 278 assert(tag_at(which).is_string(), "Corrupted constant pool"); | |
| 279 // Must do an acquire here in case another thread resolved the klass | |
| 280 // behind our back, lest we later load stale values thru the oop. | |
| 281 return (oop)OrderAccess::load_ptr_acquire(obj_at_addr(which)); | |
| 282 } | |
| 283 | |
| 284 // This method should only be used with a cpool lock or during parsing or gc | |
| 285 symbolOop unresolved_string_at(int which) { // Temporary until actual use | |
| 286 symbolOop s = symbolOop((oop)OrderAccess::load_ptr_acquire(obj_at_addr(which))); | |
| 287 // check that the string is still unresolved. | |
| 288 assert(tag_at(which).is_unresolved_string(), "Corrupted constant pool"); | |
| 289 return s; | |
| 290 } | |
| 291 | |
| 292 // Returns an UTF8 for a CONSTANT_String entry at a given index. | |
| 293 // UTF8 char* representation was chosen to avoid conversion of | |
| 294 // java_lang_Strings at resolved entries into symbolOops | |
| 295 // or vice versa. | |
| 296 char* string_at_noresolve(int which); | |
| 297 | |
| 298 jint name_and_type_at(int which) { | |
| 299 assert(tag_at(which).is_name_and_type(), "Corrupted constant pool"); | |
| 300 return *int_at_addr(which); | |
| 301 } | |
| 302 | |
| 303 // The following methods (klass_ref_at, klass_ref_at_noresolve, name_ref_at, | |
| 304 // signature_ref_at, klass_ref_index_at, name_and_type_ref_index_at, | |
| 305 // name_ref_index_at, signature_ref_index_at) all expect constant pool indices | |
| 306 // from the bytecodes to be passed in, which are actually potentially byte-swapped | |
| 307 // contstant pool cache indices. See field_or_method_at. | |
| 308 | |
| 309 // Lookup for entries consisting of (klass_index, name_and_type index) | |
| 310 klassOop klass_ref_at(int which, TRAPS); | |
| 311 symbolOop klass_ref_at_noresolve(int which); | |
| 312 symbolOop name_ref_at(int which); | |
| 313 symbolOop signature_ref_at(int which); // the type descriptor | |
| 314 | |
| 315 int klass_ref_index_at(int which); | |
| 316 int name_and_type_ref_index_at(int which); | |
| 317 | |
| 318 // Lookup for entries consisting of (name_index, signature_index) | |
| 319 int name_ref_index_at(int which); | |
| 320 int signature_ref_index_at(int which); | |
| 321 | |
| 322 BasicType basic_type_for_signature_at(int which); | |
| 323 | |
| 324 // Resolve string constants (to prevent allocation during compilation) | |
| 325 void resolve_string_constants(TRAPS) { | |
| 326 constantPoolHandle h_this(THREAD, this); | |
| 327 resolve_string_constants_impl(h_this, CHECK); | |
| 328 } | |
| 329 | |
| 330 // Klass name matches name at offset | |
| 331 bool klass_name_at_matches(instanceKlassHandle k, int which); | |
| 332 | |
| 333 // Sizing | |
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334 int length() const { return _length; } |
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335 void set_length(int length) { _length = length; } |
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336 |
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337 // Tells whether index is within bounds. |
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338 bool is_within_bounds(int index) const { |
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339 return 0 <= index && index < length(); |
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340 } |
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341 |
| 0 | 342 static int header_size() { return sizeof(constantPoolOopDesc)/HeapWordSize; } |
| 343 static int object_size(int length) { return align_object_size(header_size() + length); } | |
| 344 int object_size() { return object_size(length()); } | |
| 345 | |
| 346 friend class constantPoolKlass; | |
| 347 friend class ClassFileParser; | |
| 348 friend class SystemDictionary; | |
| 349 | |
| 350 // Used by compiler to prevent classloading. | |
| 351 static klassOop klass_at_if_loaded (constantPoolHandle this_oop, int which); | |
| 352 static klassOop klass_ref_at_if_loaded (constantPoolHandle this_oop, int which); | |
| 353 // Same as above - but does LinkResolving. | |
| 354 static klassOop klass_ref_at_if_loaded_check(constantPoolHandle this_oop, int which, TRAPS); | |
| 355 | |
| 356 // Routines currently used for annotations (only called by jvm.cpp) but which might be used in the | |
| 357 // future by other Java code. These take constant pool indices rather than possibly-byte-swapped | |
| 358 // constant pool cache indices as do the peer methods above. | |
| 359 symbolOop uncached_name_ref_at(int which); | |
| 360 symbolOop uncached_signature_ref_at(int which); | |
| 361 int uncached_klass_ref_index_at(int which); | |
| 362 int uncached_name_and_type_ref_index_at(int which); | |
| 363 | |
| 364 // Sharing | |
| 365 int pre_resolve_shared_klasses(TRAPS); | |
| 366 void shared_symbols_iterate(OopClosure* closure0); | |
| 367 void shared_tags_iterate(OopClosure* closure0); | |
| 368 void shared_strings_iterate(OopClosure* closure0); | |
| 369 | |
| 370 // Debugging | |
| 371 const char* printable_name_at(int which) PRODUCT_RETURN0; | |
| 372 | |
| 373 private: | |
| 374 | |
| 375 // Takes either a constant pool cache index in possibly byte-swapped | |
| 376 // byte order (which comes from the bytecodes after rewriting) or, | |
| 377 // if "uncached" is true, a vanilla constant pool index | |
| 378 jint field_or_method_at(int which, bool uncached) { | |
| 379 int i = -1; | |
| 380 if (uncached || cache() == NULL) { | |
| 381 i = which; | |
| 382 } else { | |
| 383 // change byte-ordering and go via cache | |
| 384 i = cache()->entry_at(Bytes::swap_u2(which))->constant_pool_index(); | |
| 385 } | |
| 386 assert(tag_at(i).is_field_or_method(), "Corrupted constant pool"); | |
| 387 return *int_at_addr(i); | |
| 388 } | |
| 389 | |
| 390 // Used while constructing constant pool (only by ClassFileParser) | |
| 391 jint klass_index_at(int which) { | |
| 392 assert(tag_at(which).is_klass_index(), "Corrupted constant pool"); | |
| 393 return *int_at_addr(which); | |
| 394 } | |
| 395 | |
| 396 jint string_index_at(int which) { | |
| 397 assert(tag_at(which).is_string_index(), "Corrupted constant pool"); | |
| 398 return *int_at_addr(which); | |
| 399 } | |
| 400 | |
| 401 // Performs the LinkResolver checks | |
| 402 static void verify_constant_pool_resolve(constantPoolHandle this_oop, KlassHandle klass, TRAPS); | |
| 403 | |
| 404 // Implementation of methods that needs an exposed 'this' pointer, in order to | |
| 405 // handle GC while executing the method | |
| 406 static klassOop klass_at_impl(constantPoolHandle this_oop, int which, TRAPS); | |
| 407 static oop string_at_impl(constantPoolHandle this_oop, int which, TRAPS); | |
| 408 | |
| 409 // Resolve string constants (to prevent allocation during compilation) | |
| 410 static void resolve_string_constants_impl(constantPoolHandle this_oop, TRAPS); | |
| 411 | |
| 412 public: | |
| 413 // Merging constantPoolOop support: | |
| 414 bool compare_entry_to(int index1, constantPoolHandle cp2, int index2, TRAPS); | |
| 415 void copy_cp_to(int start_i, int end_i, constantPoolHandle to_cp, int to_i, | |
| 416 TRAPS); | |
| 417 void copy_entry_to(int from_i, constantPoolHandle to_cp, int to_i, TRAPS); | |
| 418 int find_matching_entry(int pattern_i, constantPoolHandle search_cp, TRAPS); | |
| 419 int orig_length() const { return _orig_length; } | |
| 420 void set_orig_length(int orig_length) { _orig_length = orig_length; } | |
| 421 | |
| 422 | |
| 423 // JVMTI accesss - GetConstantPool, RetransformClasses, ... | |
| 424 friend class JvmtiConstantPoolReconstituter; | |
| 425 | |
| 426 private: | |
| 427 jint cpool_entry_size(jint idx); | |
| 428 jint hash_entries_to(SymbolHashMap *symmap, SymbolHashMap *classmap); | |
| 429 | |
| 430 // Copy cpool bytes into byte array. | |
| 431 // Returns: | |
| 432 // int > 0, count of the raw cpool bytes that have been copied | |
| 433 // 0, OutOfMemory error | |
| 434 // -1, Internal error | |
| 435 int copy_cpool_bytes(int cpool_size, | |
| 436 SymbolHashMap* tbl, | |
| 437 unsigned char *bytes); | |
| 438 }; | |
| 439 | |
| 440 class SymbolHashMapEntry : public CHeapObj { | |
| 441 private: | |
| 442 unsigned int _hash; // 32-bit hash for item | |
| 443 SymbolHashMapEntry* _next; // Next element in the linked list for this bucket | |
| 444 symbolOop _symbol; // 1-st part of the mapping: symbol => value | |
| 445 u2 _value; // 2-nd part of the mapping: symbol => value | |
| 446 | |
| 447 public: | |
| 448 unsigned int hash() const { return _hash; } | |
| 449 void set_hash(unsigned int hash) { _hash = hash; } | |
| 450 | |
| 451 SymbolHashMapEntry* next() const { return _next; } | |
| 452 void set_next(SymbolHashMapEntry* next) { _next = next; } | |
| 453 | |
| 454 symbolOop symbol() const { return _symbol; } | |
| 455 void set_symbol(symbolOop sym) { _symbol = sym; } | |
| 456 | |
| 457 u2 value() const { return _value; } | |
| 458 void set_value(u2 value) { _value = value; } | |
| 459 | |
| 460 SymbolHashMapEntry(unsigned int hash, symbolOop symbol, u2 value) | |
| 461 : _hash(hash), _symbol(symbol), _value(value), _next(NULL) {} | |
| 462 | |
| 463 }; // End SymbolHashMapEntry class | |
| 464 | |
| 465 | |
| 466 class SymbolHashMapBucket : public CHeapObj { | |
| 467 | |
| 468 private: | |
| 469 SymbolHashMapEntry* _entry; | |
| 470 | |
| 471 public: | |
| 472 SymbolHashMapEntry* entry() const { return _entry; } | |
| 473 void set_entry(SymbolHashMapEntry* entry) { _entry = entry; } | |
| 474 void clear() { _entry = NULL; } | |
| 475 | |
| 476 }; // End SymbolHashMapBucket class | |
| 477 | |
| 478 | |
| 479 class SymbolHashMap: public CHeapObj { | |
| 480 | |
| 481 private: | |
| 482 // Default number of entries in the table | |
| 483 enum SymbolHashMap_Constants { | |
| 484 _Def_HashMap_Size = 256 | |
| 485 }; | |
| 486 | |
| 487 int _table_size; | |
| 488 SymbolHashMapBucket* _buckets; | |
| 489 | |
| 490 void initialize_table(int table_size) { | |
| 491 _table_size = table_size; | |
| 492 _buckets = NEW_C_HEAP_ARRAY(SymbolHashMapBucket, table_size); | |
| 493 for (int index = 0; index < table_size; index++) { | |
| 494 _buckets[index].clear(); | |
| 495 } | |
| 496 } | |
| 497 | |
| 498 public: | |
| 499 | |
| 500 int table_size() const { return _table_size; } | |
| 501 | |
| 502 SymbolHashMap() { initialize_table(_Def_HashMap_Size); } | |
| 503 SymbolHashMap(int table_size) { initialize_table(table_size); } | |
| 504 | |
| 505 // hash P(31) from Kernighan & Ritchie | |
| 506 static unsigned int compute_hash(const char* str, int len) { | |
| 507 unsigned int hash = 0; | |
| 508 while (len-- > 0) { | |
| 509 hash = 31*hash + (unsigned) *str; | |
| 510 str++; | |
| 511 } | |
| 512 return hash; | |
| 513 } | |
| 514 | |
| 515 SymbolHashMapEntry* bucket(int i) { | |
| 516 return _buckets[i].entry(); | |
| 517 } | |
| 518 | |
| 519 void add_entry(symbolOop sym, u2 value); | |
| 520 SymbolHashMapEntry* find_entry(symbolOop sym); | |
| 521 | |
| 522 u2 symbol_to_value(symbolOop sym) { | |
| 523 SymbolHashMapEntry *entry = find_entry(sym); | |
| 524 return (entry == NULL) ? 0 : entry->value(); | |
| 525 } | |
| 526 | |
| 527 ~SymbolHashMap() { | |
| 528 SymbolHashMapEntry* next; | |
| 529 for (int i = 0; i < _table_size; i++) { | |
| 530 for (SymbolHashMapEntry* cur = bucket(i); cur != NULL; cur = next) { | |
| 531 next = cur->next(); | |
| 532 delete(cur); | |
| 533 } | |
| 534 } | |
| 535 delete _buckets; | |
| 536 } | |
| 537 }; // End SymbolHashMap class |