1 /* 2 * Copyright (c) 1997, 2018, 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 */ 24 25 #ifndef SHARE_VM_OOPS_CONSTANTPOOLOOP_HPP 26 #define SHARE_VM_OOPS_CONSTANTPOOLOOP_HPP 27 28 #include "memory/allocation.hpp" 29 #include "oops/arrayOop.hpp" 30 #include "oops/cpCache.hpp" 31 #include "oops/objArrayOop.hpp" 32 #include "oops/oopHandle.hpp" 33 #include "oops/symbol.hpp" 34 #include "oops/typeArrayOop.hpp" 35 #include "runtime/handles.hpp" 36 #include "utilities/align.hpp" 37 #include "utilities/bytes.hpp" 38 #include "utilities/constantTag.hpp" 39 40 // A ConstantPool is an array containing class constants as described in the 41 // class file. 42 // 43 // Most of the constant pool entries are written during class parsing, which 44 // is safe. For klass types, the constant pool entry is 45 // modified when the entry is resolved. If a klass constant pool 46 // entry is read without a lock, only the resolved state guarantees that 47 // the entry in the constant pool is a klass object and not a Symbol*. 48 49 class SymbolHashMap; 50 51 class CPSlot { 52 friend class ConstantPool; 53 intptr_t _ptr; 54 enum TagBits {_pseudo_bit = 1}; 55 public: 56 CPSlot(intptr_t ptr)57 CPSlot(intptr_t ptr): _ptr(ptr) {} CPSlot(Symbol * ptr,int tag_bits=0)58 CPSlot(Symbol* ptr, int tag_bits = 0): _ptr((intptr_t)ptr | tag_bits) {} 59 value()60 intptr_t value() { return _ptr; } is_pseudo_string()61 bool is_pseudo_string() { return (_ptr & _pseudo_bit) != 0; } 62 get_symbol()63 Symbol* get_symbol() { 64 return (Symbol*)(_ptr & ~_pseudo_bit); 65 } 66 }; 67 68 // This represents a JVM_CONSTANT_Class, JVM_CONSTANT_UnresolvedClass, or 69 // JVM_CONSTANT_UnresolvedClassInError slot in the constant pool. 70 class CPKlassSlot { 71 // cp->symbol_at(_name_index) gives the name of the class. 72 int _name_index; 73 74 // cp->_resolved_klasses->at(_resolved_klass_index) gives the Klass* for the class. 75 int _resolved_klass_index; 76 public: 77 enum { 78 // This is used during constant pool merging where the resolved klass index is 79 // not yet known, and will be computed at a later stage (during a call to 80 // initialize_unresolved_klasses()). 81 _temp_resolved_klass_index = 0xffff 82 }; CPKlassSlot(int n,int rk)83 CPKlassSlot(int n, int rk) { 84 _name_index = n; 85 _resolved_klass_index = rk; 86 } name_index() const87 int name_index() const { 88 return _name_index; 89 } resolved_klass_index() const90 int resolved_klass_index() const { 91 assert(_resolved_klass_index != _temp_resolved_klass_index, "constant pool merging was incomplete"); 92 return _resolved_klass_index; 93 } 94 }; 95 96 class KlassSizeStats; 97 98 class ConstantPool : public Metadata { 99 friend class VMStructs; 100 friend class JVMCIVMStructs; 101 friend class BytecodeInterpreter; // Directly extracts a klass in the pool for fast instanceof/checkcast 102 friend class Universe; // For null constructor 103 private: 104 // If you add a new field that points to any metaspace object, you 105 // must add this field to ConstantPool::metaspace_pointers_do(). 106 Array<u1>* _tags; // the tag array describing the constant pool's contents 107 ConstantPoolCache* _cache; // the cache holding interpreter runtime information 108 InstanceKlass* _pool_holder; // the corresponding class 109 Array<u2>* _operands; // for variable-sized (InvokeDynamic) nodes, usually empty 110 111 // Consider using an array of compressed klass pointers to 112 // save space on 64-bit platforms. 113 Array<Klass*>* _resolved_klasses; 114 115 enum { 116 _has_preresolution = 1, // Flags 117 _on_stack = 2, 118 _is_shared = 4, 119 _has_dynamic_constant = 8 120 }; 121 122 int _flags; // old fashioned bit twiddling 123 int _length; // number of elements in the array 124 125 union { 126 // set for CDS to restore resolved references 127 int _resolved_reference_length; 128 // keeps version number for redefined classes (used in backtrace) 129 int _version; 130 } _saved; 131 set_tags(Array<u1> * tags)132 void set_tags(Array<u1>* tags) { _tags = tags; } tag_at_put(int which,jbyte t)133 void tag_at_put(int which, jbyte t) { tags()->at_put(which, t); } 134 void release_tag_at_put(int which, jbyte t); 135 tag_addr_at(int which) const136 u1* tag_addr_at(int which) const { return tags()->adr_at(which); } 137 set_operands(Array<u2> * operands)138 void set_operands(Array<u2>* operands) { _operands = operands; } 139 flags() const140 int flags() const { return _flags; } set_flags(int f)141 void set_flags(int f) { _flags = f; } 142 143 private: base() const144 intptr_t* base() const { return (intptr_t*) (((char*) this) + sizeof(ConstantPool)); } 145 146 CPSlot slot_at(int which) const; 147 slot_at_put(int which,CPSlot s) const148 void slot_at_put(int which, CPSlot s) const { 149 assert(is_within_bounds(which), "index out of bounds"); 150 assert(s.value() != 0, "Caught something"); 151 *(intptr_t*)&base()[which] = s.value(); 152 } obj_at_addr(int which) const153 intptr_t* obj_at_addr(int which) const { 154 assert(is_within_bounds(which), "index out of bounds"); 155 return (intptr_t*) &base()[which]; 156 } 157 int_at_addr(int which) const158 jint* int_at_addr(int which) const { 159 assert(is_within_bounds(which), "index out of bounds"); 160 return (jint*) &base()[which]; 161 } 162 long_at_addr(int which) const163 jlong* long_at_addr(int which) const { 164 assert(is_within_bounds(which), "index out of bounds"); 165 return (jlong*) &base()[which]; 166 } 167 float_at_addr(int which) const168 jfloat* float_at_addr(int which) const { 169 assert(is_within_bounds(which), "index out of bounds"); 170 return (jfloat*) &base()[which]; 171 } 172 double_at_addr(int which) const173 jdouble* double_at_addr(int which) const { 174 assert(is_within_bounds(which), "index out of bounds"); 175 return (jdouble*) &base()[which]; 176 } 177 178 ConstantPool(Array<u1>* tags); ConstantPool()179 ConstantPool() { assert(DumpSharedSpaces || UseSharedSpaces, "only for CDS"); } 180 public: 181 static ConstantPool* allocate(ClassLoaderData* loader_data, int length, TRAPS); 182 is_constantPool() const183 bool is_constantPool() const volatile { return true; } 184 tags() const185 Array<u1>* tags() const { return _tags; } operands() const186 Array<u2>* operands() const { return _operands; } 187 has_preresolution() const188 bool has_preresolution() const { return (_flags & _has_preresolution) != 0; } set_has_preresolution()189 void set_has_preresolution() { 190 assert(!is_shared(), "should never be called on shared ConstantPools"); 191 _flags |= _has_preresolution; 192 } 193 194 // Redefine classes support. If a method refering to this constant pool 195 // is on the executing stack, or as a handle in vm code, this constant pool 196 // can't be removed from the set of previous versions saved in the instance 197 // class. on_stack() const198 bool on_stack() const { return (_flags &_on_stack) != 0; } 199 void set_on_stack(const bool value); 200 201 // Faster than MetaspaceObj::is_shared() - used by set_on_stack() is_shared() const202 bool is_shared() const { return (_flags & _is_shared) != 0; } 203 has_dynamic_constant() const204 bool has_dynamic_constant() const { return (_flags & _has_dynamic_constant) != 0; } set_has_dynamic_constant()205 void set_has_dynamic_constant() { _flags |= _has_dynamic_constant; } 206 207 // Klass holding pool pool_holder() const208 InstanceKlass* pool_holder() const { return _pool_holder; } set_pool_holder(InstanceKlass * k)209 void set_pool_holder(InstanceKlass* k) { _pool_holder = k; } pool_holder_addr()210 InstanceKlass** pool_holder_addr() { return &_pool_holder; } 211 212 // Interpreter runtime support cache() const213 ConstantPoolCache* cache() const { return _cache; } set_cache(ConstantPoolCache * cache)214 void set_cache(ConstantPoolCache* cache){ _cache = cache; } 215 216 virtual void metaspace_pointers_do(MetaspaceClosure* iter); type() const217 virtual MetaspaceObj::Type type() const { return ConstantPoolType; } 218 219 // Create object cache in the constant pool 220 void initialize_resolved_references(ClassLoaderData* loader_data, 221 const intStack& reference_map, 222 int constant_pool_map_length, 223 TRAPS); 224 225 // resolved strings, methodHandles and callsite objects from the constant pool 226 objArrayOop resolved_references() const; 227 objArrayOop resolved_references_or_null() const; 228 // mapping resolved object array indexes to cp indexes and back. object_to_cp_index(int index)229 int object_to_cp_index(int index) { return reference_map()->at(index); } 230 int cp_to_object_index(int index); 231 set_resolved_klasses(Array<Klass * > * rk)232 void set_resolved_klasses(Array<Klass*>* rk) { _resolved_klasses = rk; } resolved_klasses() const233 Array<Klass*>* resolved_klasses() const { return _resolved_klasses; } 234 void allocate_resolved_klasses(ClassLoaderData* loader_data, int num_klasses, TRAPS); 235 void initialize_unresolved_klasses(ClassLoaderData* loader_data, TRAPS); 236 237 // Invokedynamic indexes. 238 // They must look completely different from normal indexes. 239 // The main reason is that byte swapping is sometimes done on normal indexes. 240 // Finally, it is helpful for debugging to tell the two apart. is_invokedynamic_index(int i)241 static bool is_invokedynamic_index(int i) { return (i < 0); } decode_invokedynamic_index(int i)242 static int decode_invokedynamic_index(int i) { assert(is_invokedynamic_index(i), ""); return ~i; } encode_invokedynamic_index(int i)243 static int encode_invokedynamic_index(int i) { assert(!is_invokedynamic_index(i), ""); return ~i; } 244 245 246 // The invokedynamic points at a CP cache entry. This entry points back 247 // at the original CP entry (CONSTANT_InvokeDynamic) and also (via f2) at an entry 248 // in the resolved_references array (which provides the appendix argument). invokedynamic_cp_cache_index(int index) const249 int invokedynamic_cp_cache_index(int index) const { 250 assert (is_invokedynamic_index(index), "should be a invokedynamic index"); 251 int cache_index = decode_invokedynamic_index(index); 252 return cache_index; 253 } invokedynamic_cp_cache_entry_at(int index) const254 ConstantPoolCacheEntry* invokedynamic_cp_cache_entry_at(int index) const { 255 // decode index that invokedynamic points to. 256 int cp_cache_index = invokedynamic_cp_cache_index(index); 257 return cache()->entry_at(cp_cache_index); 258 } 259 260 // Assembly code support tags_offset_in_bytes()261 static int tags_offset_in_bytes() { return offset_of(ConstantPool, _tags); } cache_offset_in_bytes()262 static int cache_offset_in_bytes() { return offset_of(ConstantPool, _cache); } pool_holder_offset_in_bytes()263 static int pool_holder_offset_in_bytes() { return offset_of(ConstantPool, _pool_holder); } resolved_klasses_offset_in_bytes()264 static int resolved_klasses_offset_in_bytes() { return offset_of(ConstantPool, _resolved_klasses); } 265 266 // Storing constants 267 268 // For temporary use while constructing constant pool klass_index_at_put(int which,int name_index)269 void klass_index_at_put(int which, int name_index) { 270 tag_at_put(which, JVM_CONSTANT_ClassIndex); 271 *int_at_addr(which) = name_index; 272 } 273 274 // Anonymous class support: 275 void klass_at_put(int class_index, int name_index, int resolved_klass_index, Klass* k, Symbol* name); 276 void klass_at_put(int class_index, Klass* k); 277 unresolved_klass_at_put(int which,int name_index,int resolved_klass_index)278 void unresolved_klass_at_put(int which, int name_index, int resolved_klass_index) { 279 release_tag_at_put(which, JVM_CONSTANT_UnresolvedClass); 280 281 assert((name_index & 0xffff0000) == 0, "must be"); 282 assert((resolved_klass_index & 0xffff0000) == 0, "must be"); 283 *int_at_addr(which) = 284 build_int_from_shorts((jushort)resolved_klass_index, (jushort)name_index); 285 } 286 method_handle_index_at_put(int which,int ref_kind,int ref_index)287 void method_handle_index_at_put(int which, int ref_kind, int ref_index) { 288 tag_at_put(which, JVM_CONSTANT_MethodHandle); 289 *int_at_addr(which) = ((jint) ref_index<<16) | ref_kind; 290 } 291 method_type_index_at_put(int which,int ref_index)292 void method_type_index_at_put(int which, int ref_index) { 293 tag_at_put(which, JVM_CONSTANT_MethodType); 294 *int_at_addr(which) = ref_index; 295 } 296 dynamic_constant_at_put(int which,int bootstrap_specifier_index,int name_and_type_index)297 void dynamic_constant_at_put(int which, int bootstrap_specifier_index, int name_and_type_index) { 298 tag_at_put(which, JVM_CONSTANT_Dynamic); 299 *int_at_addr(which) = ((jint) name_and_type_index<<16) | bootstrap_specifier_index; 300 } 301 invoke_dynamic_at_put(int which,int bootstrap_specifier_index,int name_and_type_index)302 void invoke_dynamic_at_put(int which, int bootstrap_specifier_index, int name_and_type_index) { 303 tag_at_put(which, JVM_CONSTANT_InvokeDynamic); 304 *int_at_addr(which) = ((jint) name_and_type_index<<16) | bootstrap_specifier_index; 305 } 306 unresolved_string_at_put(int which,Symbol * s)307 void unresolved_string_at_put(int which, Symbol* s) { 308 release_tag_at_put(which, JVM_CONSTANT_String); 309 slot_at_put(which, CPSlot(s)); 310 } 311 int_at_put(int which,jint i)312 void int_at_put(int which, jint i) { 313 tag_at_put(which, JVM_CONSTANT_Integer); 314 *int_at_addr(which) = i; 315 } 316 long_at_put(int which,jlong l)317 void long_at_put(int which, jlong l) { 318 tag_at_put(which, JVM_CONSTANT_Long); 319 // *long_at_addr(which) = l; 320 Bytes::put_native_u8((address)long_at_addr(which), *((u8*) &l)); 321 } 322 float_at_put(int which,jfloat f)323 void float_at_put(int which, jfloat f) { 324 tag_at_put(which, JVM_CONSTANT_Float); 325 *float_at_addr(which) = f; 326 } 327 double_at_put(int which,jdouble d)328 void double_at_put(int which, jdouble d) { 329 tag_at_put(which, JVM_CONSTANT_Double); 330 // *double_at_addr(which) = d; 331 // u8 temp = *(u8*) &d; 332 Bytes::put_native_u8((address) double_at_addr(which), *((u8*) &d)); 333 } 334 symbol_at_addr(int which) const335 Symbol** symbol_at_addr(int which) const { 336 assert(is_within_bounds(which), "index out of bounds"); 337 return (Symbol**) &base()[which]; 338 } 339 symbol_at_put(int which,Symbol * s)340 void symbol_at_put(int which, Symbol* s) { 341 assert(s->refcount() != 0, "should have nonzero refcount"); 342 tag_at_put(which, JVM_CONSTANT_Utf8); 343 *symbol_at_addr(which) = s; 344 } 345 346 void string_at_put(int which, int obj_index, oop str); 347 348 // For temporary use while constructing constant pool string_index_at_put(int which,int string_index)349 void string_index_at_put(int which, int string_index) { 350 tag_at_put(which, JVM_CONSTANT_StringIndex); 351 *int_at_addr(which) = string_index; 352 } 353 field_at_put(int which,int class_index,int name_and_type_index)354 void field_at_put(int which, int class_index, int name_and_type_index) { 355 tag_at_put(which, JVM_CONSTANT_Fieldref); 356 *int_at_addr(which) = ((jint) name_and_type_index<<16) | class_index; 357 } 358 method_at_put(int which,int class_index,int name_and_type_index)359 void method_at_put(int which, int class_index, int name_and_type_index) { 360 tag_at_put(which, JVM_CONSTANT_Methodref); 361 *int_at_addr(which) = ((jint) name_and_type_index<<16) | class_index; 362 } 363 interface_method_at_put(int which,int class_index,int name_and_type_index)364 void interface_method_at_put(int which, int class_index, int name_and_type_index) { 365 tag_at_put(which, JVM_CONSTANT_InterfaceMethodref); 366 *int_at_addr(which) = ((jint) name_and_type_index<<16) | class_index; // Not so nice 367 } 368 name_and_type_at_put(int which,int name_index,int signature_index)369 void name_and_type_at_put(int which, int name_index, int signature_index) { 370 tag_at_put(which, JVM_CONSTANT_NameAndType); 371 *int_at_addr(which) = ((jint) signature_index<<16) | name_index; // Not so nice 372 } 373 374 // Tag query 375 376 constantTag tag_at(int which) const; 377 378 // Fetching constants 379 klass_at(int which,TRAPS)380 Klass* klass_at(int which, TRAPS) { 381 constantPoolHandle h_this(THREAD, this); 382 return klass_at_impl(h_this, which, true, THREAD); 383 } 384 385 // Version of klass_at that doesn't save the resolution error, called during deopt klass_at_ignore_error(int which,TRAPS)386 Klass* klass_at_ignore_error(int which, TRAPS) { 387 constantPoolHandle h_this(THREAD, this); 388 return klass_at_impl(h_this, which, false, THREAD); 389 } 390 klass_slot_at(int which) const391 CPKlassSlot klass_slot_at(int which) const { 392 assert(tag_at(which).is_unresolved_klass() || tag_at(which).is_klass(), 393 "Corrupted constant pool"); 394 int value = *int_at_addr(which); 395 int name_index = extract_high_short_from_int(value); 396 int resolved_klass_index = extract_low_short_from_int(value); 397 return CPKlassSlot(name_index, resolved_klass_index); 398 } 399 400 Symbol* klass_name_at(int which) const; // Returns the name, w/o resolving. klass_name_index_at(int which) const401 int klass_name_index_at(int which) const { 402 return klass_slot_at(which).name_index(); 403 } 404 405 Klass* resolved_klass_at(int which) const; // Used by Compiler 406 407 // RedefineClasses() API support: klass_at_noresolve(int which)408 Symbol* klass_at_noresolve(int which) { return klass_name_at(which); } temp_unresolved_klass_at_put(int which,int name_index)409 void temp_unresolved_klass_at_put(int which, int name_index) { 410 // Used only during constant pool merging for class redefinition. The resolved klass index 411 // will be initialized later by a call to initialize_unresolved_klasses(). 412 unresolved_klass_at_put(which, name_index, CPKlassSlot::_temp_resolved_klass_index); 413 } 414 int_at(int which)415 jint int_at(int which) { 416 assert(tag_at(which).is_int(), "Corrupted constant pool"); 417 return *int_at_addr(which); 418 } 419 long_at(int which)420 jlong long_at(int which) { 421 assert(tag_at(which).is_long(), "Corrupted constant pool"); 422 // return *long_at_addr(which); 423 u8 tmp = Bytes::get_native_u8((address)&base()[which]); 424 return *((jlong*)&tmp); 425 } 426 float_at(int which)427 jfloat float_at(int which) { 428 assert(tag_at(which).is_float(), "Corrupted constant pool"); 429 return *float_at_addr(which); 430 } 431 double_at(int which)432 jdouble double_at(int which) { 433 assert(tag_at(which).is_double(), "Corrupted constant pool"); 434 u8 tmp = Bytes::get_native_u8((address)&base()[which]); 435 return *((jdouble*)&tmp); 436 } 437 symbol_at(int which) const438 Symbol* symbol_at(int which) const { 439 assert(tag_at(which).is_utf8(), "Corrupted constant pool"); 440 return *symbol_at_addr(which); 441 } 442 string_at(int which,int obj_index,TRAPS)443 oop string_at(int which, int obj_index, TRAPS) { 444 constantPoolHandle h_this(THREAD, this); 445 return string_at_impl(h_this, which, obj_index, THREAD); 446 } string_at(int which,TRAPS)447 oop string_at(int which, TRAPS) { 448 int obj_index = cp_to_object_index(which); 449 return string_at(which, obj_index, THREAD); 450 } 451 452 // Version that can be used before string oop array is created. 453 oop uncached_string_at(int which, TRAPS); 454 455 // A "pseudo-string" is an non-string oop that has found its way into 456 // a String entry. 457 // This can happen if the user patches a live 458 // object into a CONSTANT_String entry of an anonymous class. 459 // Method oops internally created for method handles may also 460 // use pseudo-strings to link themselves to related metaobjects. 461 462 bool is_pseudo_string_at(int which); 463 464 oop pseudo_string_at(int which, int obj_index); 465 466 oop pseudo_string_at(int which); 467 pseudo_string_at_put(int which,int obj_index,oop x)468 void pseudo_string_at_put(int which, int obj_index, oop x) { 469 assert(tag_at(which).is_string(), "Corrupted constant pool"); 470 Symbol* sym = unresolved_string_at(which); 471 slot_at_put(which, CPSlot(sym, CPSlot::_pseudo_bit)); 472 string_at_put(which, obj_index, x); // this works just fine 473 } 474 475 // only called when we are sure a string entry is already resolved (via an 476 // earlier string_at call. resolved_string_at(int which)477 oop resolved_string_at(int which) { 478 assert(tag_at(which).is_string(), "Corrupted constant pool"); 479 // Must do an acquire here in case another thread resolved the klass 480 // behind our back, lest we later load stale values thru the oop. 481 // we might want a volatile_obj_at in ObjArrayKlass. 482 int obj_index = cp_to_object_index(which); 483 return resolved_references()->obj_at(obj_index); 484 } 485 unresolved_string_at(int which)486 Symbol* unresolved_string_at(int which) { 487 assert(tag_at(which).is_string(), "Corrupted constant pool"); 488 Symbol* sym = slot_at(which).get_symbol(); 489 return sym; 490 } 491 492 // Returns an UTF8 for a CONSTANT_String entry at a given index. 493 // UTF8 char* representation was chosen to avoid conversion of 494 // java_lang_Strings at resolved entries into Symbol*s 495 // or vice versa. 496 char* string_at_noresolve(int which); 497 name_and_type_at(int which)498 jint name_and_type_at(int which) { 499 assert(tag_at(which).is_name_and_type(), "Corrupted constant pool"); 500 return *int_at_addr(which); 501 } 502 method_handle_ref_kind_at(int which)503 int method_handle_ref_kind_at(int which) { 504 assert(tag_at(which).is_method_handle() || 505 tag_at(which).is_method_handle_in_error(), "Corrupted constant pool"); 506 return extract_low_short_from_int(*int_at_addr(which)); // mask out unwanted ref_index bits 507 } method_handle_index_at(int which)508 int method_handle_index_at(int which) { 509 assert(tag_at(which).is_method_handle() || 510 tag_at(which).is_method_handle_in_error(), "Corrupted constant pool"); 511 return extract_high_short_from_int(*int_at_addr(which)); // shift out unwanted ref_kind bits 512 } method_type_index_at(int which)513 int method_type_index_at(int which) { 514 assert(tag_at(which).is_method_type() || 515 tag_at(which).is_method_type_in_error(), "Corrupted constant pool"); 516 return *int_at_addr(which); 517 } 518 519 // Derived queries: method_handle_name_ref_at(int which)520 Symbol* method_handle_name_ref_at(int which) { 521 int member = method_handle_index_at(which); 522 return impl_name_ref_at(member, true); 523 } method_handle_signature_ref_at(int which)524 Symbol* method_handle_signature_ref_at(int which) { 525 int member = method_handle_index_at(which); 526 return impl_signature_ref_at(member, true); 527 } method_handle_klass_index_at(int which)528 int method_handle_klass_index_at(int which) { 529 int member = method_handle_index_at(which); 530 return impl_klass_ref_index_at(member, true); 531 } method_type_signature_at(int which)532 Symbol* method_type_signature_at(int which) { 533 int sym = method_type_index_at(which); 534 return symbol_at(sym); 535 } 536 invoke_dynamic_name_and_type_ref_index_at(int which)537 int invoke_dynamic_name_and_type_ref_index_at(int which) { 538 assert(tag_at(which).is_invoke_dynamic() || 539 tag_at(which).is_dynamic_constant() || 540 tag_at(which).is_dynamic_constant_in_error(), "Corrupted constant pool"); 541 return extract_high_short_from_int(*int_at_addr(which)); 542 } invoke_dynamic_bootstrap_specifier_index(int which)543 int invoke_dynamic_bootstrap_specifier_index(int which) { 544 assert(tag_at(which).is_invoke_dynamic() || 545 tag_at(which).is_dynamic_constant() || 546 tag_at(which).is_dynamic_constant_in_error(), "Corrupted constant pool"); 547 return extract_low_short_from_int(*int_at_addr(which)); 548 } invoke_dynamic_operand_base(int which)549 int invoke_dynamic_operand_base(int which) { 550 int bootstrap_specifier_index = invoke_dynamic_bootstrap_specifier_index(which); 551 return operand_offset_at(operands(), bootstrap_specifier_index); 552 } 553 // The first part of the operands array consists of an index into the second part. 554 // Extract a 32-bit index value from the first part. operand_offset_at(Array<u2> * operands,int bootstrap_specifier_index)555 static int operand_offset_at(Array<u2>* operands, int bootstrap_specifier_index) { 556 int n = (bootstrap_specifier_index * 2); 557 assert(n >= 0 && n+2 <= operands->length(), "oob"); 558 // The first 32-bit index points to the beginning of the second part 559 // of the operands array. Make sure this index is in the first part. 560 DEBUG_ONLY(int second_part = build_int_from_shorts(operands->at(0), 561 operands->at(1))); 562 assert(second_part == 0 || n+2 <= second_part, "oob (2)"); 563 int offset = build_int_from_shorts(operands->at(n+0), 564 operands->at(n+1)); 565 // The offset itself must point into the second part of the array. 566 assert(offset == 0 || offset >= second_part && offset <= operands->length(), "oob (3)"); 567 return offset; 568 } operand_offset_at_put(Array<u2> * operands,int bootstrap_specifier_index,int offset)569 static void operand_offset_at_put(Array<u2>* operands, int bootstrap_specifier_index, int offset) { 570 int n = bootstrap_specifier_index * 2; 571 assert(n >= 0 && n+2 <= operands->length(), "oob"); 572 operands->at_put(n+0, extract_low_short_from_int(offset)); 573 operands->at_put(n+1, extract_high_short_from_int(offset)); 574 } operand_array_length(Array<u2> * operands)575 static int operand_array_length(Array<u2>* operands) { 576 if (operands == NULL || operands->length() == 0) return 0; 577 int second_part = operand_offset_at(operands, 0); 578 return (second_part / 2); 579 } 580 581 #ifdef ASSERT 582 // operand tuples fit together exactly, end to end operand_limit_at(Array<u2> * operands,int bootstrap_specifier_index)583 static int operand_limit_at(Array<u2>* operands, int bootstrap_specifier_index) { 584 int nextidx = bootstrap_specifier_index + 1; 585 if (nextidx == operand_array_length(operands)) 586 return operands->length(); 587 else 588 return operand_offset_at(operands, nextidx); 589 } invoke_dynamic_operand_limit(int which)590 int invoke_dynamic_operand_limit(int which) { 591 int bootstrap_specifier_index = invoke_dynamic_bootstrap_specifier_index(which); 592 return operand_limit_at(operands(), bootstrap_specifier_index); 593 } 594 #endif //ASSERT 595 596 // layout of InvokeDynamic and Dynamic bootstrap method specifier (in second part of operands array): 597 enum { 598 _indy_bsm_offset = 0, // CONSTANT_MethodHandle bsm 599 _indy_argc_offset = 1, // u2 argc 600 _indy_argv_offset = 2 // u2 argv[argc] 601 }; 602 603 // These functions are used in RedefineClasses for CP merge 604 operand_offset_at(int bootstrap_specifier_index)605 int operand_offset_at(int bootstrap_specifier_index) { 606 assert(0 <= bootstrap_specifier_index && 607 bootstrap_specifier_index < operand_array_length(operands()), 608 "Corrupted CP operands"); 609 return operand_offset_at(operands(), bootstrap_specifier_index); 610 } operand_bootstrap_method_ref_index_at(int bootstrap_specifier_index)611 int operand_bootstrap_method_ref_index_at(int bootstrap_specifier_index) { 612 int offset = operand_offset_at(bootstrap_specifier_index); 613 return operands()->at(offset + _indy_bsm_offset); 614 } operand_argument_count_at(int bootstrap_specifier_index)615 int operand_argument_count_at(int bootstrap_specifier_index) { 616 int offset = operand_offset_at(bootstrap_specifier_index); 617 int argc = operands()->at(offset + _indy_argc_offset); 618 return argc; 619 } operand_argument_index_at(int bootstrap_specifier_index,int j)620 int operand_argument_index_at(int bootstrap_specifier_index, int j) { 621 int offset = operand_offset_at(bootstrap_specifier_index); 622 return operands()->at(offset + _indy_argv_offset + j); 623 } operand_next_offset_at(int bootstrap_specifier_index)624 int operand_next_offset_at(int bootstrap_specifier_index) { 625 int offset = operand_offset_at(bootstrap_specifier_index) + _indy_argv_offset 626 + operand_argument_count_at(bootstrap_specifier_index); 627 return offset; 628 } 629 // Compare a bootsrap specifier in the operands arrays 630 bool compare_operand_to(int bootstrap_specifier_index1, const constantPoolHandle& cp2, 631 int bootstrap_specifier_index2, TRAPS); 632 // Find a bootsrap specifier in the operands array 633 int find_matching_operand(int bootstrap_specifier_index, const constantPoolHandle& search_cp, 634 int operands_cur_len, TRAPS); 635 // Resize the operands array with delta_len and delta_size 636 void resize_operands(int delta_len, int delta_size, TRAPS); 637 // Extend the operands array with the length and size of the ext_cp operands 638 void extend_operands(const constantPoolHandle& ext_cp, TRAPS); 639 // Shrink the operands array to a smaller array with new_len length 640 void shrink_operands(int new_len, TRAPS); 641 invoke_dynamic_bootstrap_method_ref_index_at(int which)642 int invoke_dynamic_bootstrap_method_ref_index_at(int which) { 643 assert(tag_at(which).is_invoke_dynamic() || 644 tag_at(which).is_dynamic_constant() || 645 tag_at(which).is_dynamic_constant_in_error(), "Corrupted constant pool"); 646 int op_base = invoke_dynamic_operand_base(which); 647 return operands()->at(op_base + _indy_bsm_offset); 648 } invoke_dynamic_argument_count_at(int which)649 int invoke_dynamic_argument_count_at(int which) { 650 assert(tag_at(which).is_invoke_dynamic() || 651 tag_at(which).is_dynamic_constant() || 652 tag_at(which).is_dynamic_constant_in_error(), "Corrupted constant pool"); 653 int op_base = invoke_dynamic_operand_base(which); 654 int argc = operands()->at(op_base + _indy_argc_offset); 655 DEBUG_ONLY(int end_offset = op_base + _indy_argv_offset + argc; 656 int next_offset = invoke_dynamic_operand_limit(which)); 657 assert(end_offset == next_offset, "matched ending"); 658 return argc; 659 } invoke_dynamic_argument_index_at(int which,int j)660 int invoke_dynamic_argument_index_at(int which, int j) { 661 int op_base = invoke_dynamic_operand_base(which); 662 DEBUG_ONLY(int argc = operands()->at(op_base + _indy_argc_offset)); 663 assert((uint)j < (uint)argc, "oob"); 664 return operands()->at(op_base + _indy_argv_offset + j); 665 } 666 667 // The following methods (name/signature/klass_ref_at, klass_ref_at_noresolve, 668 // name_and_type_ref_index_at) all expect to be passed indices obtained 669 // directly from the bytecode. 670 // If the indices are meant to refer to fields or methods, they are 671 // actually rewritten constant pool cache indices. 672 // The routine remap_instruction_operand_from_cache manages the adjustment 673 // of these values back to constant pool indices. 674 675 // There are also "uncached" versions which do not adjust the operand index; see below. 676 677 // FIXME: Consider renaming these with a prefix "cached_" to make the distinction clear. 678 // In a few cases (the verifier) there are uses before a cpcache has been built, 679 // which are handled by a dynamic check in remap_instruction_operand_from_cache. 680 // FIXME: Remove the dynamic check, and adjust all callers to specify the correct mode. 681 682 // Lookup for entries consisting of (klass_index, name_and_type index) 683 Klass* klass_ref_at(int which, TRAPS); 684 Symbol* klass_ref_at_noresolve(int which); name_ref_at(int which)685 Symbol* name_ref_at(int which) { return impl_name_ref_at(which, false); } signature_ref_at(int which)686 Symbol* signature_ref_at(int which) { return impl_signature_ref_at(which, false); } 687 klass_ref_index_at(int which)688 int klass_ref_index_at(int which) { return impl_klass_ref_index_at(which, false); } name_and_type_ref_index_at(int which)689 int name_and_type_ref_index_at(int which) { return impl_name_and_type_ref_index_at(which, false); } 690 691 int remap_instruction_operand_from_cache(int operand); // operand must be biased by CPCACHE_INDEX_TAG 692 tag_ref_at(int cp_cache_index)693 constantTag tag_ref_at(int cp_cache_index) { return impl_tag_ref_at(cp_cache_index, false); } 694 695 // Lookup for entries consisting of (name_index, signature_index) 696 int name_ref_index_at(int which_nt); // == low-order jshort of name_and_type_at(which_nt) 697 int signature_ref_index_at(int which_nt); // == high-order jshort of name_and_type_at(which_nt) 698 699 BasicType basic_type_for_signature_at(int which) const; 700 701 // Resolve string constants (to prevent allocation during compilation) resolve_string_constants(TRAPS)702 void resolve_string_constants(TRAPS) { 703 constantPoolHandle h_this(THREAD, this); 704 resolve_string_constants_impl(h_this, CHECK); 705 } 706 707 // CDS support 708 void archive_resolved_references(Thread *THREAD) NOT_CDS_JAVA_HEAP_RETURN; 709 void resolve_class_constants(TRAPS) NOT_CDS_JAVA_HEAP_RETURN; 710 void remove_unshareable_info(); 711 void restore_unshareable_info(TRAPS); 712 // The ConstantPool vtable is restored by this call when the ConstantPool is 713 // in the shared archive. See patch_klass_vtables() in metaspaceShared.cpp for 714 // all the gory details. SA, dtrace and pstack helpers distinguish metadata 715 // by their vtable. restore_vtable()716 void restore_vtable() { guarantee(is_constantPool(), "vtable restored by this call"); } 717 718 private: 719 enum { _no_index_sentinel = -1, _possible_index_sentinel = -2 }; 720 public: 721 722 // Get the tag for a constant, which may involve a constant dynamic 723 constantTag constant_tag_at(int which); 724 // Get the basic type for a constant, which may involve a constant dynamic 725 BasicType basic_type_for_constant_at(int which); 726 727 // Resolve late bound constants. resolve_constant_at(int index,TRAPS)728 oop resolve_constant_at(int index, TRAPS) { 729 constantPoolHandle h_this(THREAD, this); 730 return resolve_constant_at_impl(h_this, index, _no_index_sentinel, NULL, THREAD); 731 } 732 resolve_cached_constant_at(int cache_index,TRAPS)733 oop resolve_cached_constant_at(int cache_index, TRAPS) { 734 constantPoolHandle h_this(THREAD, this); 735 return resolve_constant_at_impl(h_this, _no_index_sentinel, cache_index, NULL, THREAD); 736 } 737 resolve_possibly_cached_constant_at(int pool_index,TRAPS)738 oop resolve_possibly_cached_constant_at(int pool_index, TRAPS) { 739 constantPoolHandle h_this(THREAD, this); 740 return resolve_constant_at_impl(h_this, pool_index, _possible_index_sentinel, NULL, THREAD); 741 } 742 find_cached_constant_at(int pool_index,bool & found_it,TRAPS)743 oop find_cached_constant_at(int pool_index, bool& found_it, TRAPS) { 744 constantPoolHandle h_this(THREAD, this); 745 return resolve_constant_at_impl(h_this, pool_index, _possible_index_sentinel, &found_it, THREAD); 746 } 747 resolve_bootstrap_specifier_at(int index,TRAPS)748 oop resolve_bootstrap_specifier_at(int index, TRAPS) { 749 constantPoolHandle h_this(THREAD, this); 750 return resolve_bootstrap_specifier_at_impl(h_this, index, THREAD); 751 } 752 copy_bootstrap_arguments_at(int index,int start_arg,int end_arg,objArrayHandle info,int pos,bool must_resolve,Handle if_not_available,TRAPS)753 void copy_bootstrap_arguments_at(int index, 754 int start_arg, int end_arg, 755 objArrayHandle info, int pos, 756 bool must_resolve, Handle if_not_available, TRAPS) { 757 constantPoolHandle h_this(THREAD, this); 758 copy_bootstrap_arguments_at_impl(h_this, index, start_arg, end_arg, 759 info, pos, must_resolve, if_not_available, THREAD); 760 } 761 762 // Klass name matches name at offset 763 bool klass_name_at_matches(const InstanceKlass* k, int which); 764 765 // Sizing length() const766 int length() const { return _length; } set_length(int length)767 void set_length(int length) { _length = length; } 768 769 // Tells whether index is within bounds. is_within_bounds(int index) const770 bool is_within_bounds(int index) const { 771 return 0 <= index && index < length(); 772 } 773 774 // Sizing (in words) header_size()775 static int header_size() { 776 return align_up((int)sizeof(ConstantPool), wordSize) / wordSize; 777 } size(int length)778 static int size(int length) { return align_metadata_size(header_size() + length); } size() const779 int size() const { return size(length()); } 780 #if INCLUDE_SERVICES 781 void collect_statistics(KlassSizeStats *sz) const; 782 #endif 783 784 // ConstantPools should be stored in the read-only region of CDS archive. is_read_only_by_default()785 static bool is_read_only_by_default() { return true; } 786 787 friend class ClassFileParser; 788 friend class SystemDictionary; 789 790 // Used by CDS. These classes need to access the private ConstantPool() constructor. 791 template <class T> friend class CppVtableTesterA; 792 template <class T> friend class CppVtableTesterB; 793 template <class T> friend class CppVtableCloner; 794 795 // Used by compiler to prevent classloading. 796 static Method* method_at_if_loaded (const constantPoolHandle& this_cp, int which); 797 static bool has_appendix_at_if_loaded (const constantPoolHandle& this_cp, int which); 798 static oop appendix_at_if_loaded (const constantPoolHandle& this_cp, int which); 799 static bool has_method_type_at_if_loaded (const constantPoolHandle& this_cp, int which); 800 static oop method_type_at_if_loaded (const constantPoolHandle& this_cp, int which); 801 static Klass* klass_at_if_loaded (const constantPoolHandle& this_cp, int which); 802 803 // Routines currently used for annotations (only called by jvm.cpp) but which might be used in the 804 // future by other Java code. These take constant pool indices rather than 805 // constant pool cache indices as do the peer methods above. 806 Symbol* uncached_klass_ref_at_noresolve(int which); uncached_name_ref_at(int which)807 Symbol* uncached_name_ref_at(int which) { return impl_name_ref_at(which, true); } uncached_signature_ref_at(int which)808 Symbol* uncached_signature_ref_at(int which) { return impl_signature_ref_at(which, true); } uncached_klass_ref_index_at(int which)809 int uncached_klass_ref_index_at(int which) { return impl_klass_ref_index_at(which, true); } uncached_name_and_type_ref_index_at(int which)810 int uncached_name_and_type_ref_index_at(int which) { return impl_name_and_type_ref_index_at(which, true); } 811 812 // Sharing 813 int pre_resolve_shared_klasses(TRAPS); 814 815 // Debugging 816 const char* printable_name_at(int which) PRODUCT_RETURN0; 817 818 #ifdef ASSERT 819 enum { CPCACHE_INDEX_TAG = 0x10000 }; // helps keep CP cache indices distinct from CP indices 820 #else 821 enum { CPCACHE_INDEX_TAG = 0 }; // in product mode, this zero value is a no-op 822 #endif //ASSERT 823 decode_cpcache_index(int raw_index,bool invokedynamic_ok=false)824 static int decode_cpcache_index(int raw_index, bool invokedynamic_ok = false) { 825 if (invokedynamic_ok && is_invokedynamic_index(raw_index)) 826 return decode_invokedynamic_index(raw_index); 827 else 828 return raw_index - CPCACHE_INDEX_TAG; 829 } 830 831 private: 832 set_resolved_references(OopHandle s)833 void set_resolved_references(OopHandle s) { _cache->set_resolved_references(s); } reference_map() const834 Array<u2>* reference_map() const { return (_cache == NULL) ? NULL : _cache->reference_map(); } set_reference_map(Array<u2> * o)835 void set_reference_map(Array<u2>* o) { _cache->set_reference_map(o); } 836 837 // patch JSR 292 resolved references after the class is linked. 838 void patch_resolved_references(GrowableArray<Handle>* cp_patches); 839 840 Symbol* impl_name_ref_at(int which, bool uncached); 841 Symbol* impl_signature_ref_at(int which, bool uncached); 842 843 int impl_klass_ref_index_at(int which, bool uncached); 844 int impl_name_and_type_ref_index_at(int which, bool uncached); 845 constantTag impl_tag_ref_at(int which, bool uncached); 846 847 // Used while constructing constant pool (only by ClassFileParser) klass_index_at(int which)848 jint klass_index_at(int which) { 849 assert(tag_at(which).is_klass_index(), "Corrupted constant pool"); 850 return *int_at_addr(which); 851 } 852 string_index_at(int which)853 jint string_index_at(int which) { 854 assert(tag_at(which).is_string_index(), "Corrupted constant pool"); 855 return *int_at_addr(which); 856 } 857 858 // Performs the LinkResolver checks 859 static void verify_constant_pool_resolve(const constantPoolHandle& this_cp, Klass* klass, TRAPS); 860 861 // Implementation of methods that needs an exposed 'this' pointer, in order to 862 // handle GC while executing the method 863 static Klass* klass_at_impl(const constantPoolHandle& this_cp, int which, 864 bool save_resolution_error, TRAPS); 865 static oop string_at_impl(const constantPoolHandle& this_cp, int which, int obj_index, TRAPS); 866 867 static void trace_class_resolution(const constantPoolHandle& this_cp, Klass* k); 868 869 // Resolve string constants (to prevent allocation during compilation) 870 static void resolve_string_constants_impl(const constantPoolHandle& this_cp, TRAPS); 871 872 static oop resolve_constant_at_impl(const constantPoolHandle& this_cp, int index, int cache_index, 873 bool* status_return, TRAPS); 874 static oop resolve_bootstrap_specifier_at_impl(const constantPoolHandle& this_cp, int index, TRAPS); 875 static void copy_bootstrap_arguments_at_impl(const constantPoolHandle& this_cp, int index, 876 int start_arg, int end_arg, 877 objArrayHandle info, int pos, 878 bool must_resolve, Handle if_not_available, TRAPS); 879 880 // Exception handling 881 static Symbol* exception_message(const constantPoolHandle& this_cp, int which, constantTag tag, oop pending_exception); 882 static void save_and_throw_exception(const constantPoolHandle& this_cp, int which, constantTag tag, TRAPS); 883 884 public: 885 // Exception handling 886 static void throw_resolution_error(const constantPoolHandle& this_cp, int which, TRAPS); 887 888 // Merging ConstantPool* support: 889 bool compare_entry_to(int index1, const constantPoolHandle& cp2, int index2, TRAPS); copy_cp_to(int start_i,int end_i,const constantPoolHandle & to_cp,int to_i,TRAPS)890 void copy_cp_to(int start_i, int end_i, const constantPoolHandle& to_cp, int to_i, TRAPS) { 891 constantPoolHandle h_this(THREAD, this); 892 copy_cp_to_impl(h_this, start_i, end_i, to_cp, to_i, THREAD); 893 } 894 static void copy_cp_to_impl(const constantPoolHandle& from_cp, int start_i, int end_i, const constantPoolHandle& to_cp, int to_i, TRAPS); 895 static void copy_entry_to(const constantPoolHandle& from_cp, int from_i, const constantPoolHandle& to_cp, int to_i, TRAPS); 896 static void copy_operands(const constantPoolHandle& from_cp, const constantPoolHandle& to_cp, TRAPS); 897 int find_matching_entry(int pattern_i, const constantPoolHandle& search_cp, TRAPS); version() const898 int version() const { return _saved._version; } set_version(int version)899 void set_version(int version) { _saved._version = version; } increment_and_save_version(int version)900 void increment_and_save_version(int version) { 901 _saved._version = version >= 0 ? (version + 1) : version; // keep overflow 902 } 903 set_resolved_reference_length(int length)904 void set_resolved_reference_length(int length) { _saved._resolved_reference_length = length; } resolved_reference_length() const905 int resolved_reference_length() const { return _saved._resolved_reference_length; } 906 907 // Decrease ref counts of symbols that are in the constant pool 908 // when the holder class is unloaded 909 void unreference_symbols(); 910 911 // Deallocate constant pool for RedefineClasses 912 void deallocate_contents(ClassLoaderData* loader_data); 913 void release_C_heap_structures(); 914 915 // JVMTI accesss - GetConstantPool, RetransformClasses, ... 916 friend class JvmtiConstantPoolReconstituter; 917 918 private: 919 jint cpool_entry_size(jint idx); 920 jint hash_entries_to(SymbolHashMap *symmap, SymbolHashMap *classmap); 921 922 // Copy cpool bytes into byte array. 923 // Returns: 924 // int > 0, count of the raw cpool bytes that have been copied 925 // 0, OutOfMemory error 926 // -1, Internal error 927 int copy_cpool_bytes(int cpool_size, 928 SymbolHashMap* tbl, 929 unsigned char *bytes); 930 931 public: 932 // Verify 933 void verify_on(outputStream* st); 934 935 // Printing 936 void print_on(outputStream* st) const; 937 void print_value_on(outputStream* st) const; 938 void print_entry_on(int index, outputStream* st); 939 internal_name() const940 const char* internal_name() const { return "{constant pool}"; } 941 942 #ifndef PRODUCT 943 // Compile the world support 944 static void preload_and_initialize_all_classes(ConstantPool* constant_pool, TRAPS); 945 #endif 946 }; 947 948 class SymbolHashMapEntry : public CHeapObj<mtSymbol> { 949 private: 950 unsigned int _hash; // 32-bit hash for item 951 SymbolHashMapEntry* _next; // Next element in the linked list for this bucket 952 Symbol* _symbol; // 1-st part of the mapping: symbol => value 953 u2 _value; // 2-nd part of the mapping: symbol => value 954 955 public: hash() const956 unsigned int hash() const { return _hash; } set_hash(unsigned int hash)957 void set_hash(unsigned int hash) { _hash = hash; } 958 next() const959 SymbolHashMapEntry* next() const { return _next; } set_next(SymbolHashMapEntry * next)960 void set_next(SymbolHashMapEntry* next) { _next = next; } 961 symbol() const962 Symbol* symbol() const { return _symbol; } set_symbol(Symbol * sym)963 void set_symbol(Symbol* sym) { _symbol = sym; } 964 value() const965 u2 value() const { return _value; } set_value(u2 value)966 void set_value(u2 value) { _value = value; } 967 SymbolHashMapEntry(unsigned int hash,Symbol * symbol,u2 value)968 SymbolHashMapEntry(unsigned int hash, Symbol* symbol, u2 value) 969 : _hash(hash), _symbol(symbol), _value(value), _next(NULL) {} 970 971 }; // End SymbolHashMapEntry class 972 973 974 class SymbolHashMapBucket : public CHeapObj<mtSymbol> { 975 976 private: 977 SymbolHashMapEntry* _entry; 978 979 public: entry() const980 SymbolHashMapEntry* entry() const { return _entry; } set_entry(SymbolHashMapEntry * entry)981 void set_entry(SymbolHashMapEntry* entry) { _entry = entry; } clear()982 void clear() { _entry = NULL; } 983 984 }; // End SymbolHashMapBucket class 985 986 987 class SymbolHashMap: public CHeapObj<mtSymbol> { 988 989 private: 990 // Default number of entries in the table 991 enum SymbolHashMap_Constants { 992 _Def_HashMap_Size = 256 993 }; 994 995 int _table_size; 996 SymbolHashMapBucket* _buckets; 997 998 void initialize_table(int table_size); 999 1000 public: 1001 table_size() const1002 int table_size() const { return _table_size; } 1003 SymbolHashMap()1004 SymbolHashMap() { initialize_table(_Def_HashMap_Size); } SymbolHashMap(int table_size)1005 SymbolHashMap(int table_size) { initialize_table(table_size); } 1006 1007 // hash P(31) from Kernighan & Ritchie compute_hash(const char * str,int len)1008 static unsigned int compute_hash(const char* str, int len) { 1009 unsigned int hash = 0; 1010 while (len-- > 0) { 1011 hash = 31*hash + (unsigned) *str; 1012 str++; 1013 } 1014 return hash; 1015 } 1016 bucket(int i)1017 SymbolHashMapEntry* bucket(int i) { 1018 return _buckets[i].entry(); 1019 } 1020 1021 void add_entry(Symbol* sym, u2 value); 1022 SymbolHashMapEntry* find_entry(Symbol* sym); 1023 symbol_to_value(Symbol * sym)1024 u2 symbol_to_value(Symbol* sym) { 1025 SymbolHashMapEntry *entry = find_entry(sym); 1026 return (entry == NULL) ? 0 : entry->value(); 1027 } 1028 1029 ~SymbolHashMap(); 1030 }; // End SymbolHashMap class 1031 1032 #endif // SHARE_VM_OOPS_CONSTANTPOOLOOP_HPP 1033