1 /* 2 * Copyright (c) 1998, 2013, 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_CPCACHEOOP_HPP 26 #define SHARE_VM_OOPS_CPCACHEOOP_HPP 27 28 #include "interpreter/bytecodes.hpp" 29 #include "memory/allocation.hpp" 30 #include "oops/arrayOop.hpp" 31 #include "utilities/array.hpp" 32 33 // A ConstantPoolCacheEntry describes an individual entry of the constant 34 // pool cache. There's 2 principal kinds of entries: field entries for in- 35 // stance & static field access, and method entries for invokes. Some of 36 // the entry layout is shared and looks as follows: 37 // 38 // bit number |31 0| 39 // bit length |-8--|-8--|---16----| 40 // -------------------------------- 41 // _indices [ b2 | b1 | index ] 42 // _f1 [ entry specific ] 43 // _f2 [ entry specific ] 44 // _flags [t|f|vf|v|m|h|unused|field_index] (for field entries) 45 // bit length |4|1|1 |1|1|0|---7--|----16-----] 46 // _flags [t|f|vf|v|m|h|unused|eidx|psze] (for method entries) 47 // bit length |4|1|1 |1|1|1|---7--|-8--|-8--] 48 49 // -------------------------------- 50 // 51 // with: 52 // index = original constant pool index 53 // b1 = bytecode 1 54 // b2 = bytecode 2 55 // psze = parameters size (method entries only) 56 // eidx = interpreter entry index (method entries only) 57 // field_index = index into field information in holder instanceKlass 58 // The index max is 0xffff (max number of fields in constant pool) 59 // and is multiplied by (instanceKlass::next_offset) when accessing. 60 // t = TosState (see below) 61 // f = field is marked final (see below) 62 // vf = virtual, final (method entries only : is_vfinal()) 63 // v = field is volatile (see below) 64 // m = invokeinterface used for method in class Object (see below) 65 // h = RedefineClasses/Hotswap bit (see below) 66 // 67 // The flags after TosState have the following interpretation: 68 // bit 27: f flag true if field is marked final 69 // bit 26: vf flag true if virtual final method 70 // bit 25: v flag true if field is volatile (only for fields) 71 // bit 24: m flag true if invokeinterface used for method in class Object 72 // bit 23: 0 for fields, 1 for methods 73 // 74 // The flags 31, 30, 29, 28 together build a 4 bit number 0 to 8 with the 75 // following mapping to the TosState states: 76 // 77 // btos: 0 78 // ctos: 1 79 // stos: 2 80 // itos: 3 81 // ltos: 4 82 // ftos: 5 83 // dtos: 6 84 // atos: 7 85 // vtos: 8 86 // 87 // Entry specific: field entries: 88 // _indices = get (b1 section) and put (b2 section) bytecodes, original constant pool index 89 // _f1 = field holder 90 // _f2 = field offset in words 91 // _flags = field type information, original field index in field holder 92 // (field_index section) 93 // 94 // Entry specific: method entries: 95 // _indices = invoke code for f1 (b1 section), invoke code for f2 (b2 section), 96 // original constant pool index 97 // _f1 = method for all but virtual calls, unused by virtual calls 98 // (note: for interface calls, which are essentially virtual, 99 // contains klassOop for the corresponding interface. 100 // for invokedynamic, f1 contains the CallSite object for the invocation 101 // _f2 = method/vtable index for virtual calls only, unused by all other 102 // calls. The vf flag indicates this is a method pointer not an 103 // index. 104 // _flags = field type info (f section), 105 // virtual final entry (vf), 106 // interpreter entry index (eidx section), 107 // parameter size (psze section) 108 // 109 // Note: invokevirtual & invokespecial bytecodes can share the same constant 110 // pool entry and thus the same constant pool cache entry. All invoke 111 // bytecodes but invokevirtual use only _f1 and the corresponding b1 112 // bytecode, while invokevirtual uses only _f2 and the corresponding 113 // b2 bytecode. The value of _flags is shared for both types of entries. 114 // 115 // The fields are volatile so that they are stored in the order written in the 116 // source code. The _indices field with the bytecode must be written last. 117 118 class ConstantPoolCacheEntry VALUE_OBJ_CLASS_SPEC { 119 friend class VMStructs; 120 friend class constantPoolCacheKlass; 121 friend class constantPoolOopDesc; //resolve_constant_at_impl => set_f1 122 123 private: 124 volatile intx _indices; // constant pool index & rewrite bytecodes 125 volatile oop _f1; // entry specific oop field 126 volatile intx _f2; // entry specific int/oop field 127 volatile intx _flags; // flags 128 129 130 #ifdef ASSERT 131 bool same_methodOop(oop cur_f1, oop f1); 132 #endif 133 134 void set_bytecode_1(Bytecodes::Code code); 135 void set_bytecode_2(Bytecodes::Code code); 136 void set_f1(oop f1) { 137 oop existing_f1 = _f1; // read once 138 assert(existing_f1 == NULL || existing_f1 == f1, "illegal field change"); 139 oop_store(&_f1, f1); 140 } 141 void set_f1_if_null_atomic(oop f1); 142 void set_f2(intx f2) { assert(_f2 == 0 || _f2 == f2, "illegal field change"); _f2 = f2; } 143 int as_flags(TosState state, bool is_final, bool is_vfinal, bool is_volatile, 144 bool is_method_interface, bool is_method); 145 void set_flags(intx flags) { _flags = flags; } 146 147 public: 148 // specific bit values in flag field 149 // Note: the interpreter knows this layout! 150 enum FlagBitValues { 151 hotSwapBit = 23, 152 methodInterface = 24, 153 volatileField = 25, 154 vfinalMethod = 26, 155 finalField = 27 156 }; 157 158 enum { field_index_mask = 0xFFFF }; 159 160 // start of type bits in flags 161 // Note: the interpreter knows this layout! 162 enum FlagValues { 163 tosBits = 28 164 }; 165 166 // Initialization 167 void initialize_entry(int original_index); // initialize primary entry 168 void initialize_secondary_entry(int main_index); // initialize secondary entry 169 170 void set_field( // sets entry to resolved field state 171 Bytecodes::Code get_code, // the bytecode used for reading the field 172 Bytecodes::Code put_code, // the bytecode used for writing the field 173 KlassHandle field_holder, // the object/klass holding the field 174 int orig_field_index, // the original field index in the field holder 175 int field_offset, // the field offset in words in the field holder 176 TosState field_type, // the (machine) field type 177 bool is_final, // the field is final 178 bool is_volatile // the field is volatile 179 ); 180 181 void set_method( // sets entry to resolved method entry 182 Bytecodes::Code invoke_code, // the bytecode used for invoking the method 183 methodHandle method, // the method/prototype if any (NULL, otherwise) 184 int vtable_index // the vtable index if any, else negative 185 ); 186 187 void set_interface_call( 188 methodHandle method, // Resolved method 189 int index // Method index into interface 190 ); 191 192 void set_dynamic_call( 193 Handle call_site, // Resolved java.lang.invoke.CallSite (f1) 194 methodHandle signature_invoker // determines signature information 195 ); 196 197 methodOop get_method_if_resolved(Bytecodes::Code invoke_code, constantPoolHandle cpool); 198 199 // For JVM_CONSTANT_InvokeDynamic cache entries: 200 void initialize_bootstrap_method_index_in_cache(int bsm_cache_index); 201 int bootstrap_method_index_in_cache(); 202 203 void set_parameter_size(int value) { 204 assert(parameter_size() == 0 || parameter_size() == value, 205 "size must not change"); 206 // Setting the parameter size by itself is only safe if the 207 // current value of _flags is 0, otherwise another thread may have 208 // updated it and we don't want to overwrite that value. Don't 209 // bother trying to update it once it's nonzero but always make 210 // sure that the final parameter size agrees with what was passed. 211 if (_flags == 0) { 212 Atomic::cmpxchg_ptr((value & 0xFF), &_flags, 0); 213 } 214 guarantee(parameter_size() == value, "size must not change"); 215 } 216 217 // Which bytecode number (1 or 2) in the index field is valid for this bytecode? 218 // Returns -1 if neither is valid. 219 static int bytecode_number(Bytecodes::Code code) { 220 switch (code) { 221 case Bytecodes::_getstatic : // fall through 222 case Bytecodes::_getfield : // fall through 223 case Bytecodes::_invokespecial : // fall through 224 case Bytecodes::_invokestatic : // fall through 225 case Bytecodes::_invokedynamic : // fall through 226 case Bytecodes::_invokeinterface : return 1; 227 case Bytecodes::_putstatic : // fall through 228 case Bytecodes::_putfield : // fall through 229 case Bytecodes::_invokevirtual : return 2; 230 default : break; 231 } 232 return -1; 233 } 234 235 // Has this bytecode been resolved? Only valid for invokes and get/put field/static. 236 bool is_resolved(Bytecodes::Code code) const { 237 switch (bytecode_number(code)) { 238 case 1: return (bytecode_1() == code); 239 case 2: return (bytecode_2() == code); 240 } 241 return false; // default: not resolved 242 } 243 244 // Accessors 245 bool is_secondary_entry() const { return (_indices & 0xFFFF) == 0; } 246 int constant_pool_index() const { assert((_indices & 0xFFFF) != 0, "must be main entry"); 247 return (_indices & 0xFFFF); } 248 int main_entry_index() const { assert((_indices & 0xFFFF) == 0, "must be secondary entry"); 249 return ((uintx)_indices >> 16); } 250 Bytecodes::Code bytecode_1() const { return Bytecodes::cast((_indices >> 16) & 0xFF); } 251 Bytecodes::Code bytecode_2() const { return Bytecodes::cast((_indices >> 24) & 0xFF); } 252 volatile oop f1() const { return _f1; } 253 bool is_f1_null() const { return (oop)_f1 == NULL; } // classifies a CPC entry as unbound 254 intx f2() const { return _f2; } 255 int field_index() const; 256 int parameter_size() const { return _flags & 0xFF; } 257 bool is_vfinal() const { return ((_flags & (1 << vfinalMethod)) == (1 << vfinalMethod)); } 258 bool is_volatile() const { return ((_flags & (1 << volatileField)) == (1 << volatileField)); } 259 bool is_methodInterface() const { return ((_flags & (1 << methodInterface)) == (1 << methodInterface)); } 260 bool is_byte() const { return (((uintx) _flags >> tosBits) == btos); } 261 bool is_char() const { return (((uintx) _flags >> tosBits) == ctos); } 262 bool is_short() const { return (((uintx) _flags >> tosBits) == stos); } 263 bool is_int() const { return (((uintx) _flags >> tosBits) == itos); } 264 bool is_long() const { return (((uintx) _flags >> tosBits) == ltos); } 265 bool is_float() const { return (((uintx) _flags >> tosBits) == ftos); } 266 bool is_double() const { return (((uintx) _flags >> tosBits) == dtos); } 267 bool is_object() const { return (((uintx) _flags >> tosBits) == atos); } 268 TosState flag_state() const { assert( ( (_flags >> tosBits) & 0x0F ) < number_of_states, "Invalid state in as_flags"); 269 return (TosState)((_flags >> tosBits) & 0x0F); } 270 271 // Code generation support 272 static WordSize size() { return in_WordSize(sizeof(ConstantPoolCacheEntry) / HeapWordSize); } 273 static ByteSize size_in_bytes() { return in_ByteSize(sizeof(ConstantPoolCacheEntry)); } 274 static ByteSize indices_offset() { return byte_offset_of(ConstantPoolCacheEntry, _indices); } 275 static ByteSize f1_offset() { return byte_offset_of(ConstantPoolCacheEntry, _f1); } 276 static ByteSize f2_offset() { return byte_offset_of(ConstantPoolCacheEntry, _f2); } 277 static ByteSize flags_offset() { return byte_offset_of(ConstantPoolCacheEntry, _flags); } 278 279 // GC Support 280 void oops_do(void f(oop*)); 281 void oop_iterate(OopClosure* blk); 282 void oop_iterate_m(OopClosure* blk, MemRegion mr); 283 void follow_contents(); 284 void adjust_pointers(); 285 286 #ifndef SERIALGC 287 // Parallel Old 288 void follow_contents(ParCompactionManager* cm); 289 #endif // SERIALGC 290 291 void update_pointers(); 292 293 // RedefineClasses() API support: 294 // If this constantPoolCacheEntry refers to old_method then update it 295 // to refer to new_method. 296 // trace_name_printed is set to true if the current call has 297 // printed the klass name so that other routines in the adjust_* 298 // group don't print the klass name. 299 bool adjust_method_entry(methodOop old_method, methodOop new_method, 300 bool * trace_name_printed); 301 bool check_no_old_or_obsolete_entries(); 302 bool is_interesting_method_entry(klassOop k); 303 bool is_field_entry() const { return (_flags & (1 << hotSwapBit)) == 0; } 304 bool is_method_entry() const { return (_flags & (1 << hotSwapBit)) != 0; } 305 306 // Debugging & Printing 307 void print (outputStream* st, int index) const; 308 void verify(outputStream* st) const; 309 310 static void verify_tosBits() { 311 assert(tosBits == 28, "interpreter now assumes tosBits is 28"); 312 } 313 }; 314 315 316 // A constant pool cache is a runtime data structure set aside to a constant pool. The cache 317 // holds interpreter runtime information for all field access and invoke bytecodes. The cache 318 // is created and initialized before a class is actively used (i.e., initialized), the indivi- 319 // dual cache entries are filled at resolution (i.e., "link") time (see also: rewriter.*). 320 321 class constantPoolCacheOopDesc: public oopDesc { 322 friend class VMStructs; 323 private: 324 int _length; 325 constantPoolOop _constant_pool; // the corresponding constant pool 326 327 // Sizing 328 debug_only(friend class ClassVerifier;) 329 public: 330 int length() const { return _length; } 331 private: 332 void set_length(int length) { _length = length; } 333 334 static int header_size() { return sizeof(constantPoolCacheOopDesc) / HeapWordSize; } 335 static int object_size(int length) { return align_object_size(header_size() + length * in_words(ConstantPoolCacheEntry::size())); } 336 int object_size() { return object_size(length()); } 337 338 // Helpers 339 constantPoolOop* constant_pool_addr() { return &_constant_pool; } 340 ConstantPoolCacheEntry* base() const { return (ConstantPoolCacheEntry*)((address)this + in_bytes(base_offset())); } 341 342 friend class constantPoolCacheKlass; 343 friend class ConstantPoolCacheEntry; 344 345 public: 346 // Initialization 347 void initialize(intArray& inverse_index_map); 348 349 // Secondary indexes. 350 // They must look completely different from normal indexes. 351 // The main reason is that byte swapping is sometimes done on normal indexes. 352 // Also, some of the CP accessors do different things for secondary indexes. 353 // Finally, it is helpful for debugging to tell the two apart. 354 static bool is_secondary_index(int i) { return (i < 0); } 355 static int decode_secondary_index(int i) { assert(is_secondary_index(i), ""); return ~i; } 356 static int encode_secondary_index(int i) { assert(!is_secondary_index(i), ""); return ~i; } 357 358 // Accessors 359 void set_constant_pool(constantPoolOop pool) { oop_store_without_check((oop*)&_constant_pool, (oop)pool); } 360 constantPoolOop constant_pool() const { return _constant_pool; } 361 // Fetches the entry at the given index. 362 // The entry may be either primary or secondary. 363 // In either case the index must not be encoded or byte-swapped in any way. 364 ConstantPoolCacheEntry* entry_at(int i) const { 365 assert(0 <= i && i < length(), "index out of bounds"); 366 return base() + i; 367 } 368 // Fetches the secondary entry referred to by index. 369 // The index may be a secondary index, and must not be byte-swapped. 370 ConstantPoolCacheEntry* secondary_entry_at(int i) const { 371 int raw_index = i; 372 if (is_secondary_index(i)) { // correct these on the fly 373 raw_index = decode_secondary_index(i); 374 } 375 assert(entry_at(raw_index)->is_secondary_entry(), "not a secondary entry"); 376 return entry_at(raw_index); 377 } 378 // Given a primary or secondary index, fetch the corresponding primary entry. 379 // Indirect through the secondary entry, if the index is encoded as a secondary index. 380 // The index must not be byte-swapped. 381 ConstantPoolCacheEntry* main_entry_at(int i) const { 382 int primary_index = i; 383 if (is_secondary_index(i)) { 384 // run through an extra level of indirection: 385 int raw_index = decode_secondary_index(i); 386 primary_index = entry_at(raw_index)->main_entry_index(); 387 } 388 assert(!entry_at(primary_index)->is_secondary_entry(), "only one level of indirection"); 389 return entry_at(primary_index); 390 } 391 392 // Code generation 393 static ByteSize base_offset() { return in_ByteSize(sizeof(constantPoolCacheOopDesc)); } 394 static ByteSize entry_offset(int raw_index) { 395 int index = raw_index; 396 if (is_secondary_index(raw_index)) 397 index = decode_secondary_index(raw_index); 398 return (base_offset() + ConstantPoolCacheEntry::size_in_bytes() * index); 399 } 400 401 // RedefineClasses() API support: 402 // If any entry of this constantPoolCache points to any of 403 // old_methods, replace it with the corresponding new_method. 404 // trace_name_printed is set to true if the current call has 405 // printed the klass name so that other routines in the adjust_* 406 // group don't print the klass name. 407 void adjust_method_entries(methodOop* old_methods, methodOop* new_methods, 408 int methods_length, bool * trace_name_printed); 409 bool check_no_old_or_obsolete_entries(); 410 void dump_cache(); 411 }; 412 413 #endif // SHARE_VM_OOPS_CPCACHEOOP_HPP