1 /* 2 * Copyright 1997-2009 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 37 class constantPoolOopDesc : public oopDesc { 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 44 int _flags; // a few header bits to describe contents for GC 45 int _length; // number of elements in the array 46 volatile bool _is_conc_safe; // if true, safe for concurrent 47 // GC processing 48 // only set to non-zero if constant pool is merged by RedefineClasses 49 int _orig_length; 50 51 void set_tags(typeArrayOop tags) { oop_store_without_check((oop*)&_tags, tags); } 52 void tag_at_put(int which, jbyte t) { tags()->byte_at_put(which, t); } 53 void release_tag_at_put(int which, jbyte t) { tags()->release_byte_at_put(which, t); } 54 55 enum FlagBit { 56 FB_has_invokedynamic = 1, 57 FB_has_pseudo_string = 2 58 }; 59 60 int flags() const { return _flags; } 61 void set_flags(int f) { _flags = f; } 62 bool flag_at(FlagBit fb) const { return (_flags & (1 << (int)fb)) != 0; } 63 void set_flag_at(FlagBit fb); 64 // no clear_flag_at function; they only increase 65 66 private: 67 intptr_t* base() const { return (intptr_t*) (((char*) this) + sizeof(constantPoolOopDesc)); } 68 oop* tags_addr() { return (oop*)&_tags; } 69 oop* cache_addr() { return (oop*)&_cache; } 70 71 oop* obj_at_addr(int which) const { 72 assert(is_within_bounds(which), "index out of bounds"); 73 return (oop*) &base()[which]; 74 } 75 76 jint* int_at_addr(int which) const { 77 assert(is_within_bounds(which), "index out of bounds"); 78 return (jint*) &base()[which]; 79 } 80 81 jlong* long_at_addr(int which) const { 82 assert(is_within_bounds(which), "index out of bounds"); 83 return (jlong*) &base()[which]; 84 } 85 86 jfloat* float_at_addr(int which) const { 87 assert(is_within_bounds(which), "index out of bounds"); 88 return (jfloat*) &base()[which]; 89 } 90 91 jdouble* double_at_addr(int which) const { 92 assert(is_within_bounds(which), "index out of bounds"); 93 return (jdouble*) &base()[which]; 94 } 95 96 public: 97 typeArrayOop tags() const { return _tags; } 98 99 bool has_pseudo_string() const { return flag_at(FB_has_pseudo_string); } 100 bool has_invokedynamic() const { return flag_at(FB_has_invokedynamic); } 101 void set_pseudo_string() { set_flag_at(FB_has_pseudo_string); } 102 void set_invokedynamic() { set_flag_at(FB_has_invokedynamic); } 103 104 // Klass holding pool 105 klassOop pool_holder() const { return _pool_holder; } 106 void set_pool_holder(klassOop k) { oop_store_without_check((oop*)&_pool_holder, (oop) k); } 107 oop* pool_holder_addr() { return (oop*)&_pool_holder; } 108 109 // Interpreter runtime support 110 constantPoolCacheOop cache() const { return _cache; } 111 void set_cache(constantPoolCacheOop cache){ oop_store((oop*)&_cache, cache); } 112 113 // Assembly code support 114 static int tags_offset_in_bytes() { return offset_of(constantPoolOopDesc, _tags); } 115 static int cache_offset_in_bytes() { return offset_of(constantPoolOopDesc, _cache); } 116 static int pool_holder_offset_in_bytes() { return offset_of(constantPoolOopDesc, _pool_holder); } 117 118 // Storing constants 119 120 void klass_at_put(int which, klassOop k) { 121 oop_store_without_check((volatile oop *)obj_at_addr(which), oop(k)); 122 // The interpreter assumes when the tag is stored, the klass is resolved 123 // and the klassOop is a klass rather than a symbolOop, so we need 124 // hardware store ordering here. 125 release_tag_at_put(which, JVM_CONSTANT_Class); 126 if (UseConcMarkSweepGC) { 127 // In case the earlier card-mark was consumed by a concurrent 128 // marking thread before the tag was updated, redirty the card. 129 oop_store_without_check((volatile oop *)obj_at_addr(which), oop(k)); 130 } 131 } 132 133 // For temporary use while constructing constant pool 134 void klass_index_at_put(int which, int name_index) { 135 tag_at_put(which, JVM_CONSTANT_ClassIndex); 136 *int_at_addr(which) = name_index; 137 } 138 139 // Temporary until actual use 140 void unresolved_klass_at_put(int which, symbolOop s) { 141 // Overwrite the old index with a GC friendly value so 142 // that if GC looks during the transition it won't try 143 // to treat a small integer as oop. 144 *obj_at_addr(which) = NULL; 145 release_tag_at_put(which, JVM_CONSTANT_UnresolvedClass); 146 oop_store_without_check(obj_at_addr(which), oop(s)); 147 } 148 149 // Temporary until actual use 150 void unresolved_string_at_put(int which, symbolOop s) { 151 *obj_at_addr(which) = NULL; 152 release_tag_at_put(which, JVM_CONSTANT_UnresolvedString); 153 oop_store_without_check(obj_at_addr(which), oop(s)); 154 } 155 156 void int_at_put(int which, jint i) { 157 tag_at_put(which, JVM_CONSTANT_Integer); 158 *int_at_addr(which) = i; 159 } 160 161 void long_at_put(int which, jlong l) { 162 tag_at_put(which, JVM_CONSTANT_Long); 163 // *long_at_addr(which) = l; 164 Bytes::put_native_u8((address)long_at_addr(which), *((u8*) &l)); 165 } 166 167 void float_at_put(int which, jfloat f) { 168 tag_at_put(which, JVM_CONSTANT_Float); 169 *float_at_addr(which) = f; 170 } 171 172 void double_at_put(int which, jdouble d) { 173 tag_at_put(which, JVM_CONSTANT_Double); 174 // *double_at_addr(which) = d; 175 // u8 temp = *(u8*) &d; 176 Bytes::put_native_u8((address) double_at_addr(which), *((u8*) &d)); 177 } 178 179 void symbol_at_put(int which, symbolOop s) { 180 tag_at_put(which, JVM_CONSTANT_Utf8); 181 oop_store_without_check(obj_at_addr(which), oop(s)); 182 } 183 184 void string_at_put(int which, oop str) { 185 oop_store((volatile oop*)obj_at_addr(which), str); 186 release_tag_at_put(which, JVM_CONSTANT_String); 187 if (UseConcMarkSweepGC) { 188 // In case the earlier card-mark was consumed by a concurrent 189 // marking thread before the tag was updated, redirty the card. 190 oop_store_without_check((volatile oop *)obj_at_addr(which), str); 191 } 192 } 193 194 // For temporary use while constructing constant pool 195 void string_index_at_put(int which, int string_index) { 196 tag_at_put(which, JVM_CONSTANT_StringIndex); 197 *int_at_addr(which) = string_index; 198 } 199 200 void field_at_put(int which, int class_index, int name_and_type_index) { 201 tag_at_put(which, JVM_CONSTANT_Fieldref); 202 *int_at_addr(which) = ((jint) name_and_type_index<<16) | class_index; 203 } 204 205 void method_at_put(int which, int class_index, int name_and_type_index) { 206 tag_at_put(which, JVM_CONSTANT_Methodref); 207 *int_at_addr(which) = ((jint) name_and_type_index<<16) | class_index; 208 } 209 210 void interface_method_at_put(int which, int class_index, int name_and_type_index) { 211 tag_at_put(which, JVM_CONSTANT_InterfaceMethodref); 212 *int_at_addr(which) = ((jint) name_and_type_index<<16) | class_index; // Not so nice 213 } 214 215 void name_and_type_at_put(int which, int name_index, int signature_index) { 216 tag_at_put(which, JVM_CONSTANT_NameAndType); 217 *int_at_addr(which) = ((jint) signature_index<<16) | name_index; // Not so nice 218 } 219 220 // Tag query 221 222 constantTag tag_at(int which) const { return (constantTag)tags()->byte_at_acquire(which); } 223 224 // Whether the entry is a pointer that must be GC'd. 225 bool is_pointer_entry(int which) { 226 constantTag tag = tag_at(which); 227 return tag.is_klass() || 228 tag.is_unresolved_klass() || 229 tag.is_symbol() || 230 tag.is_unresolved_string() || 231 tag.is_string(); 232 } 233 234 // Fetching constants 235 236 klassOop klass_at(int which, TRAPS) { 237 constantPoolHandle h_this(THREAD, this); 238 return klass_at_impl(h_this, which, CHECK_NULL); 239 } 240 241 symbolOop klass_name_at(int which); // Returns the name, w/o resolving. 242 243 klassOop resolved_klass_at(int which) { // Used by Compiler 244 guarantee(tag_at(which).is_klass(), "Corrupted constant pool"); 245 // Must do an acquire here in case another thread resolved the klass 246 // behind our back, lest we later load stale values thru the oop. 247 return klassOop((oop)OrderAccess::load_ptr_acquire(obj_at_addr(which))); 248 } 249 250 // This method should only be used with a cpool lock or during parsing or gc 251 symbolOop unresolved_klass_at(int which) { // Temporary until actual use 252 symbolOop s = symbolOop((oop)OrderAccess::load_ptr_acquire(obj_at_addr(which))); 253 // check that the klass is still unresolved. 254 assert(tag_at(which).is_unresolved_klass(), "Corrupted constant pool"); 255 return s; 256 } 257 258 // RedefineClasses() API support: 259 symbolOop klass_at_noresolve(int which) { return klass_name_at(which); } 260 261 jint int_at(int which) { 262 assert(tag_at(which).is_int(), "Corrupted constant pool"); 263 return *int_at_addr(which); 264 } 265 266 jlong long_at(int which) { 267 assert(tag_at(which).is_long(), "Corrupted constant pool"); 268 // return *long_at_addr(which); 269 u8 tmp = Bytes::get_native_u8((address)&base()[which]); 270 return *((jlong*)&tmp); 271 } 272 273 jfloat float_at(int which) { 274 assert(tag_at(which).is_float(), "Corrupted constant pool"); 275 return *float_at_addr(which); 276 } 277 278 jdouble double_at(int which) { 279 assert(tag_at(which).is_double(), "Corrupted constant pool"); 280 u8 tmp = Bytes::get_native_u8((address)&base()[which]); 281 return *((jdouble*)&tmp); 282 } 283 284 symbolOop symbol_at(int which) { 285 assert(tag_at(which).is_utf8(), "Corrupted constant pool"); 286 return symbolOop(*obj_at_addr(which)); 287 } 288 289 oop string_at(int which, TRAPS) { 290 constantPoolHandle h_this(THREAD, this); 291 return string_at_impl(h_this, which, CHECK_NULL); 292 } 293 294 // A "pseudo-string" is an non-string oop that has found is way into 295 // a String entry. 296 // Under AnonymousClasses this can happen if the user patches a live 297 // object into a CONSTANT_String entry of an anonymous class. 298 // Method oops internally created for method handles may also 299 // use pseudo-strings to link themselves to related metaobjects. 300 301 bool is_pseudo_string_at(int which); 302 303 oop pseudo_string_at(int which) { 304 assert(tag_at(which).is_string(), "Corrupted constant pool"); 305 return *obj_at_addr(which); 306 } 307 308 void pseudo_string_at_put(int which, oop x) { 309 assert(AnonymousClasses, ""); 310 set_pseudo_string(); // mark header 311 assert(tag_at(which).is_string() || tag_at(which).is_unresolved_string(), "Corrupted constant pool"); 312 string_at_put(which, x); // this works just fine 313 } 314 315 // only called when we are sure a string entry is already resolved (via an 316 // earlier string_at call. 317 oop resolved_string_at(int which) { 318 assert(tag_at(which).is_string(), "Corrupted constant pool"); 319 // Must do an acquire here in case another thread resolved the klass 320 // behind our back, lest we later load stale values thru the oop. 321 return (oop)OrderAccess::load_ptr_acquire(obj_at_addr(which)); 322 } 323 324 // This method should only be used with a cpool lock or during parsing or gc 325 symbolOop unresolved_string_at(int which) { // Temporary until actual use 326 symbolOop s = symbolOop((oop)OrderAccess::load_ptr_acquire(obj_at_addr(which))); 327 // check that the string is still unresolved. 328 assert(tag_at(which).is_unresolved_string(), "Corrupted constant pool"); 329 return s; 330 } 331 332 // Returns an UTF8 for a CONSTANT_String entry at a given index. 333 // UTF8 char* representation was chosen to avoid conversion of 334 // java_lang_Strings at resolved entries into symbolOops 335 // or vice versa. 336 // Caller is responsible for checking for pseudo-strings. 337 char* string_at_noresolve(int which); 338 339 jint name_and_type_at(int which) { 340 assert(tag_at(which).is_name_and_type(), "Corrupted constant pool"); 341 return *int_at_addr(which); 342 } 343 344 // The following methods (name/signature/klass_ref_at, klass_ref_at_noresolve, 345 // name_and_type_ref_index_at) all expect to be passed indices obtained 346 // directly from the bytecode, and extracted according to java byte order. 347 // If the indices are meant to refer to fields or methods, they are 348 // actually potentially byte-swapped, rewritten constant pool cache indices. 349 // The routine remap_instruction_operand_from_cache manages the adjustment 350 // of these values back to constant pool indices. 351 352 // There are also "uncached" versions which do not adjust the operand index; see below. 353 354 // Lookup for entries consisting of (klass_index, name_and_type index) 355 klassOop klass_ref_at(int which, TRAPS); 356 symbolOop klass_ref_at_noresolve(int which); 357 symbolOop name_ref_at(int which) { return impl_name_ref_at(which, false); } 358 symbolOop signature_ref_at(int which) { return impl_signature_ref_at(which, false); } 359 360 int klass_ref_index_at(int which) { return impl_klass_ref_index_at(which, false); } 361 int name_and_type_ref_index_at(int which) { return impl_name_and_type_ref_index_at(which, false); } 362 363 // Lookup for entries consisting of (name_index, signature_index) 364 int name_ref_index_at(int which_nt); // == low-order jshort of name_and_type_at(which_nt) 365 int signature_ref_index_at(int which_nt); // == high-order jshort of name_and_type_at(which_nt) 366 367 BasicType basic_type_for_signature_at(int which); 368 369 // Resolve string constants (to prevent allocation during compilation) 370 void resolve_string_constants(TRAPS) { 371 constantPoolHandle h_this(THREAD, this); 372 resolve_string_constants_impl(h_this, CHECK); 373 } 374 375 // Klass name matches name at offset 376 bool klass_name_at_matches(instanceKlassHandle k, int which); 377 378 // Sizing 379 int length() const { return _length; } 380 void set_length(int length) { _length = length; } 381 382 // Tells whether index is within bounds. 383 bool is_within_bounds(int index) const { 384 return 0 <= index && index < length(); 385 } 386 387 static int header_size() { return sizeof(constantPoolOopDesc)/HeapWordSize; } 388 static int object_size(int length) { return align_object_size(header_size() + length); } 389 int object_size() { return object_size(length()); } 390 391 bool is_conc_safe() { return _is_conc_safe; } 392 void set_is_conc_safe(bool v) { _is_conc_safe = v; } 393 394 friend class constantPoolKlass; 395 friend class ClassFileParser; 396 friend class SystemDictionary; 397 398 // Used by compiler to prevent classloading. 399 static klassOop klass_at_if_loaded (constantPoolHandle this_oop, int which); 400 static klassOop klass_ref_at_if_loaded (constantPoolHandle this_oop, int which); 401 // Same as above - but does LinkResolving. 402 static klassOop klass_ref_at_if_loaded_check(constantPoolHandle this_oop, int which, TRAPS); 403 404 // Routines currently used for annotations (only called by jvm.cpp) but which might be used in the 405 // future by other Java code. These take constant pool indices rather than possibly-byte-swapped 406 // constant pool cache indices as do the peer methods above. 407 symbolOop uncached_name_ref_at(int which) { return impl_name_ref_at(which, true); } 408 symbolOop uncached_signature_ref_at(int which) { return impl_signature_ref_at(which, true); } 409 int uncached_klass_ref_index_at(int which) { return impl_klass_ref_index_at(which, true); } 410 int uncached_name_and_type_ref_index_at(int which) { return impl_name_and_type_ref_index_at(which, true); } 411 412 // Sharing 413 int pre_resolve_shared_klasses(TRAPS); 414 void shared_symbols_iterate(OopClosure* closure0); 415 void shared_tags_iterate(OopClosure* closure0); 416 void shared_strings_iterate(OopClosure* closure0); 417 418 // Debugging 419 const char* printable_name_at(int which) PRODUCT_RETURN0; 420 421 private: 422 423 symbolOop impl_name_ref_at(int which, bool uncached); 424 symbolOop impl_signature_ref_at(int which, bool uncached); 425 int impl_klass_ref_index_at(int which, bool uncached); 426 int impl_name_and_type_ref_index_at(int which, bool uncached); 427 428 int remap_instruction_operand_from_cache(int operand); 429 430 // Used while constructing constant pool (only by ClassFileParser) 431 jint klass_index_at(int which) { 432 assert(tag_at(which).is_klass_index(), "Corrupted constant pool"); 433 return *int_at_addr(which); 434 } 435 436 jint string_index_at(int which) { 437 assert(tag_at(which).is_string_index(), "Corrupted constant pool"); 438 return *int_at_addr(which); 439 } 440 441 // Performs the LinkResolver checks 442 static void verify_constant_pool_resolve(constantPoolHandle this_oop, KlassHandle klass, TRAPS); 443 444 // Implementation of methods that needs an exposed 'this' pointer, in order to 445 // handle GC while executing the method 446 static klassOop klass_at_impl(constantPoolHandle this_oop, int which, TRAPS); 447 static oop string_at_impl(constantPoolHandle this_oop, int which, TRAPS); 448 449 // Resolve string constants (to prevent allocation during compilation) 450 static void resolve_string_constants_impl(constantPoolHandle this_oop, TRAPS); 451 452 public: 453 // Merging constantPoolOop support: 454 bool compare_entry_to(int index1, constantPoolHandle cp2, int index2, TRAPS); 455 void copy_cp_to(int start_i, int end_i, constantPoolHandle to_cp, int to_i, 456 TRAPS); 457 void copy_entry_to(int from_i, constantPoolHandle to_cp, int to_i, TRAPS); 458 int find_matching_entry(int pattern_i, constantPoolHandle search_cp, TRAPS); 459 int orig_length() const { return _orig_length; } 460 void set_orig_length(int orig_length) { _orig_length = orig_length; } 461 462 463 // JVMTI accesss - GetConstantPool, RetransformClasses, ... 464 friend class JvmtiConstantPoolReconstituter; 465 466 private: 467 jint cpool_entry_size(jint idx); 468 jint hash_entries_to(SymbolHashMap *symmap, SymbolHashMap *classmap); 469 470 // Copy cpool bytes into byte array. 471 // Returns: 472 // int > 0, count of the raw cpool bytes that have been copied 473 // 0, OutOfMemory error 474 // -1, Internal error 475 int copy_cpool_bytes(int cpool_size, 476 SymbolHashMap* tbl, 477 unsigned char *bytes); 478 }; 479 480 class SymbolHashMapEntry : public CHeapObj { 481 private: 482 unsigned int _hash; // 32-bit hash for item 483 SymbolHashMapEntry* _next; // Next element in the linked list for this bucket 484 symbolOop _symbol; // 1-st part of the mapping: symbol => value 485 u2 _value; // 2-nd part of the mapping: symbol => value 486 487 public: 488 unsigned int hash() const { return _hash; } 489 void set_hash(unsigned int hash) { _hash = hash; } 490 491 SymbolHashMapEntry* next() const { return _next; } 492 void set_next(SymbolHashMapEntry* next) { _next = next; } 493 494 symbolOop symbol() const { return _symbol; } 495 void set_symbol(symbolOop sym) { _symbol = sym; } 496 497 u2 value() const { return _value; } 498 void set_value(u2 value) { _value = value; } 499 500 SymbolHashMapEntry(unsigned int hash, symbolOop symbol, u2 value) 501 : _hash(hash), _symbol(symbol), _value(value), _next(NULL) {} 502 503 }; // End SymbolHashMapEntry class 504 505 506 class SymbolHashMapBucket : public CHeapObj { 507 508 private: 509 SymbolHashMapEntry* _entry; 510 511 public: 512 SymbolHashMapEntry* entry() const { return _entry; } 513 void set_entry(SymbolHashMapEntry* entry) { _entry = entry; } 514 void clear() { _entry = NULL; } 515 516 }; // End SymbolHashMapBucket class 517 518 519 class SymbolHashMap: public CHeapObj { 520 521 private: 522 // Default number of entries in the table 523 enum SymbolHashMap_Constants { 524 _Def_HashMap_Size = 256 525 }; 526 527 int _table_size; 528 SymbolHashMapBucket* _buckets; 529 530 void initialize_table(int table_size) { 531 _table_size = table_size; 532 _buckets = NEW_C_HEAP_ARRAY(SymbolHashMapBucket, table_size); 533 for (int index = 0; index < table_size; index++) { 534 _buckets[index].clear(); 535 } 536 } 537 538 public: 539 540 int table_size() const { return _table_size; } 541 542 SymbolHashMap() { initialize_table(_Def_HashMap_Size); } 543 SymbolHashMap(int table_size) { initialize_table(table_size); } 544 545 // hash P(31) from Kernighan & Ritchie 546 static unsigned int compute_hash(const char* str, int len) { 547 unsigned int hash = 0; 548 while (len-- > 0) { 549 hash = 31*hash + (unsigned) *str; 550 str++; 551 } 552 return hash; 553 } 554 555 SymbolHashMapEntry* bucket(int i) { 556 return _buckets[i].entry(); 557 } 558 559 void add_entry(symbolOop sym, u2 value); 560 SymbolHashMapEntry* find_entry(symbolOop sym); 561 562 u2 symbol_to_value(symbolOop sym) { 563 SymbolHashMapEntry *entry = find_entry(sym); 564 return (entry == NULL) ? 0 : entry->value(); 565 } 566 567 ~SymbolHashMap() { 568 SymbolHashMapEntry* next; 569 for (int i = 0; i < _table_size; i++) { 570 for (SymbolHashMapEntry* cur = bucket(i); cur != NULL; cur = next) { 571 next = cur->next(); 572 delete(cur); 573 } 574 } 575 delete _buckets; 576 } 577 }; // End SymbolHashMap class