1 /* 2 * Copyright (c) 1999, 2019, 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 #include "precompiled.hpp" 26 #include "ci/ciConstant.hpp" 27 #include "ci/ciField.hpp" 28 #include "ci/ciKlass.hpp" 29 #include "ci/ciObjArrayKlass.hpp" 30 #include "ci/ciStreams.hpp" 31 #include "ci/ciSymbols.hpp" 32 #include "ci/ciUtilities.inline.hpp" 33 #include "runtime/handles.inline.hpp" 34 35 // ciExceptionHandlerStream 36 // 37 // Walk over some selected set of a methods exception handlers. 38 39 // ------------------------------------------------------------------ 40 // ciExceptionHandlerStream::count 41 // 42 // How many exception handlers are there in this stream? 43 // 44 // Implementation note: Compiler2 needs this functionality, so I had 45 int ciExceptionHandlerStream::count() { 46 int save_pos = _pos; 47 int save_end = _end; 48 49 int count = 0; 50 51 _pos = -1; 52 _end = _method->_handler_count; 53 54 55 next(); 56 while (!is_done()) { 57 count++; 58 next(); 59 } 60 61 _pos = save_pos; 62 _end = save_end; 63 64 return count; 65 } 66 67 int ciExceptionHandlerStream::count_remaining() { 68 int save_pos = _pos; 69 int save_end = _end; 70 71 int count = 0; 72 73 while (!is_done()) { 74 count++; 75 next(); 76 } 77 78 _pos = save_pos; 79 _end = save_end; 80 81 return count; 82 } 83 84 // ciBytecodeStream 85 // 86 // The class is used to iterate over the bytecodes of a method. 87 // It hides the details of constant pool structure/access by 88 // providing accessors for constant pool items. 89 90 // ------------------------------------------------------------------ 91 // ciBytecodeStream::next_wide_or_table 92 // 93 // Special handling for switch ops 94 Bytecodes::Code ciBytecodeStream::next_wide_or_table(Bytecodes::Code bc) { 95 switch (bc) { // Check for special bytecode handling 96 case Bytecodes::_wide: 97 // Special handling for the wide bytcode 98 // Get following bytecode; do not return wide 99 assert(Bytecodes::Code(_pc[0]) == Bytecodes::_wide, ""); 100 bc = Bytecodes::java_code(_raw_bc = (Bytecodes::Code)_pc[1]); 101 assert(Bytecodes::wide_length_for(bc) > 2, "must make progress"); 102 _pc += Bytecodes::wide_length_for(bc); 103 _was_wide = _pc; // Flag last wide bytecode found 104 assert(is_wide(), "accessor works right"); 105 break; 106 107 case Bytecodes::_lookupswitch: 108 _pc++; // Skip wide bytecode 109 _pc += (_start-_pc)&3; // Word align 110 _table_base = (jint*)_pc; // Capture for later usage 111 // table_base[0] is default far_dest 112 // Table has 2 lead elements (default, length), then pairs of u4 values. 113 // So load table length, and compute address at end of table 114 _pc = (address)&_table_base[2+ 2*Bytes::get_Java_u4((address)&_table_base[1])]; 115 break; 116 117 case Bytecodes::_tableswitch: { 118 _pc++; // Skip wide bytecode 119 _pc += (_start-_pc)&3; // Word align 120 _table_base = (jint*)_pc; // Capture for later usage 121 // table_base[0] is default far_dest 122 int lo = Bytes::get_Java_u4((address)&_table_base[1]);// Low bound 123 int hi = Bytes::get_Java_u4((address)&_table_base[2]);// High bound 124 int len = hi - lo + 1; // Dense table size 125 _pc = (address)&_table_base[3+len]; // Skip past table 126 break; 127 } 128 129 default: 130 fatal("unhandled bytecode"); 131 } 132 return bc; 133 } 134 135 // ------------------------------------------------------------------ 136 // ciBytecodeStream::reset_to_bci 137 void ciBytecodeStream::reset_to_bci( int bci ) { 138 _bc_start=_was_wide=0; 139 _pc = _start+bci; 140 } 141 142 // ------------------------------------------------------------------ 143 // ciBytecodeStream::force_bci 144 void ciBytecodeStream::force_bci(int bci) { 145 if (bci < 0) { 146 reset_to_bci(0); 147 _bc_start = _start + bci; 148 _bc = EOBC(); 149 } else { 150 reset_to_bci(bci); 151 next(); 152 } 153 } 154 155 156 // ------------------------------------------------------------------ 157 // Constant pool access 158 // ------------------------------------------------------------------ 159 160 // ------------------------------------------------------------------ 161 // ciBytecodeStream::get_klass_index 162 // 163 // If this bytecodes references a klass, return the index of the 164 // referenced klass. 165 int ciBytecodeStream::get_klass_index() const { 166 switch(cur_bc()) { 167 case Bytecodes::_ldc: 168 return get_index_u1(); 169 case Bytecodes::_ldc_w: 170 case Bytecodes::_ldc2_w: 171 case Bytecodes::_checkcast: 172 case Bytecodes::_instanceof: 173 case Bytecodes::_anewarray: 174 case Bytecodes::_multianewarray: 175 case Bytecodes::_new: 176 case Bytecodes::_newarray: 177 return get_index_u2(); 178 default: 179 ShouldNotReachHere(); 180 return 0; 181 } 182 } 183 184 // ------------------------------------------------------------------ 185 // ciBytecodeStream::get_klass 186 // 187 // If this bytecode is a new, newarray, multianewarray, instanceof, 188 // or checkcast, get the referenced klass. 189 ciKlass* ciBytecodeStream::get_klass(bool& will_link) { 190 VM_ENTRY_MARK; 191 constantPoolHandle cpool(THREAD, _method->get_Method()->constants()); 192 return CURRENT_ENV->get_klass_by_index(cpool, get_klass_index(), will_link, _holder); 193 } 194 195 // ciBytecodeStream::get_klass 196 // 197 // If this bytecode is a new, newarray, multianewarray, instanceof, 198 // or checkcast, get the referenced klass. Retuns an unloaded ciKlass 199 // if the referenced klass is not accessible. 200 ciKlass* ciBytecodeStream::get_klass() { 201 bool will_link; 202 ciKlass* klass = get_klass(will_link); 203 if (!will_link && klass->is_loaded()) { // klass not accessible 204 VM_ENTRY_MARK; 205 klass = CURRENT_ENV->get_unloaded_klass(_holder, klass->name()); 206 } 207 return klass; 208 } 209 210 // ------------------------------------------------------------------ 211 // ciBytecodeStream::get_constant_raw_index 212 // 213 // If this bytecode is one of the ldc variants, get the index of the 214 // referenced constant. 215 int ciBytecodeStream::get_constant_raw_index() const { 216 // work-alike for Bytecode_loadconstant::raw_index() 217 switch (cur_bc()) { 218 case Bytecodes::_ldc: 219 return get_index_u1(); 220 case Bytecodes::_ldc_w: 221 case Bytecodes::_ldc2_w: 222 return get_index_u2(); 223 default: 224 ShouldNotReachHere(); 225 return 0; 226 } 227 } 228 229 // ------------------------------------------------------------------ 230 // ciBytecodeStream::get_constant_pool_index 231 // Decode any reference index into a regular pool index. 232 int ciBytecodeStream::get_constant_pool_index() const { 233 // work-alike for Bytecode_loadconstant::pool_index() 234 int index = get_constant_raw_index(); 235 if (has_cache_index()) { 236 VM_ENTRY_MARK; 237 constantPoolHandle cpool(THREAD, _method->get_Method()->constants()); 238 return cpool->object_to_cp_index(index); 239 } 240 return index; 241 } 242 243 // ------------------------------------------------------------------ 244 // ciBytecodeStream::get_constant 245 // 246 // If this bytecode is one of the ldc variants, get the referenced 247 // constant. 248 ciConstant ciBytecodeStream::get_constant() { 249 VM_ENTRY_MARK; 250 constantPoolHandle cpool(THREAD, _method->get_Method()->constants()); 251 int pool_index = get_constant_raw_index(); 252 int cache_index = -1; 253 if (has_cache_index()) { 254 cache_index = pool_index; 255 pool_index = cpool->object_to_cp_index(cache_index); 256 } else if (cpool->tag_at(pool_index).is_dynamic_constant() || 257 cpool->tag_at(pool_index).is_dynamic_constant_in_error()) { 258 // Condy with primitive type is not quickened, so the index into resolved reference cache should be reconstructed. 259 assert(is_java_primitive(cpool->basic_type_for_constant_at(pool_index)), "not quickened"); 260 cache_index = cpool->cp_to_object_index(pool_index); 261 } 262 return CURRENT_ENV->get_constant_by_index(cpool, pool_index, cache_index, _holder); 263 } 264 265 // ------------------------------------------------------------------ 266 // ciBytecodeStream::get_constant_pool_tag 267 // 268 // If this bytecode is one of the ldc variants, get the referenced 269 // constant. 270 constantTag ciBytecodeStream::get_constant_pool_tag(int index) const { 271 VM_ENTRY_MARK; 272 return _method->get_Method()->constants()->constant_tag_at(index); 273 } 274 275 // ------------------------------------------------------------------ 276 // ciBytecodeStream::get_raw_pool_tag 277 // 278 constantTag ciBytecodeStream::get_raw_pool_tag_at(int index) const { 279 VM_ENTRY_MARK; 280 return _method->get_Method()->constants()->tag_at(index); 281 } 282 283 // ------------------------------------------------------------------ 284 // ciBytecodeStream::get_basic_type_for_constant_at 285 // 286 BasicType ciBytecodeStream::get_basic_type_for_constant_at(int index) const { 287 VM_ENTRY_MARK; 288 return _method->get_Method()->constants()->basic_type_for_constant_at(index); 289 } 290 291 // ------------------------------------------------------------------ 292 // ciBytecodeStream::get_field_index 293 // 294 // If this is a field access bytecode, get the constant pool 295 // index of the referenced field. 296 int ciBytecodeStream::get_field_index() { 297 assert(cur_bc() == Bytecodes::_getfield || 298 cur_bc() == Bytecodes::_putfield || 299 cur_bc() == Bytecodes::_getstatic || 300 cur_bc() == Bytecodes::_putstatic, "wrong bc"); 301 return get_index_u2_cpcache(); 302 } 303 304 305 // ------------------------------------------------------------------ 306 // ciBytecodeStream::get_field 307 // 308 // If this bytecode is one of get_field, get_static, put_field, 309 // or put_static, get the referenced field. 310 ciField* ciBytecodeStream::get_field(bool& will_link) { 311 ciField* f = CURRENT_ENV->get_field_by_index(_holder, get_field_index()); 312 will_link = f->will_link(_method, _bc); 313 return f; 314 } 315 316 317 // ------------------------------------------------------------------ 318 // ciBytecodeStream::get_declared_field_holder 319 // 320 // Get the declared holder of the currently referenced field. 321 // 322 // Usage note: the holder() of a ciField class returns the canonical 323 // holder of the field, rather than the holder declared in the 324 // bytecodes. 325 // 326 // There is no "will_link" result passed back. The user is responsible 327 // for checking linkability when retrieving the associated field. 328 ciInstanceKlass* ciBytecodeStream::get_declared_field_holder() { 329 VM_ENTRY_MARK; 330 constantPoolHandle cpool(THREAD, _method->get_Method()->constants()); 331 int holder_index = get_field_holder_index(); 332 bool ignore; 333 return CURRENT_ENV->get_klass_by_index(cpool, holder_index, ignore, _holder) 334 ->as_instance_klass(); 335 } 336 337 // ------------------------------------------------------------------ 338 // ciBytecodeStream::get_field_holder_index 339 // 340 // Get the constant pool index of the declared holder of the field 341 // referenced by the current bytecode. Used for generating 342 // deoptimization information. 343 int ciBytecodeStream::get_field_holder_index() { 344 GUARDED_VM_ENTRY( 345 ConstantPool* cpool = _holder->get_instanceKlass()->constants(); 346 return cpool->klass_ref_index_at(get_field_index()); 347 ) 348 } 349 350 // ------------------------------------------------------------------ 351 // ciBytecodeStream::get_method_index 352 // 353 // If this is a method invocation bytecode, get the constant pool 354 // index of the invoked method. 355 int ciBytecodeStream::get_method_index() { 356 assert(Bytecodes::is_invoke(cur_bc()), "invalid bytecode: %s", Bytecodes::name(cur_bc())); 357 if (has_index_u4()) 358 return get_index_u4(); // invokedynamic 359 return get_index_u2_cpcache(); 360 } 361 362 // ------------------------------------------------------------------ 363 // ciBytecodeStream::get_method 364 // 365 // If this is a method invocation bytecode, get the invoked method. 366 // Additionally return the declared signature to get more concrete 367 // type information if required (Cf. invokedynamic and invokehandle). 368 ciMethod* ciBytecodeStream::get_method(bool& will_link, ciSignature* *declared_signature_result) { 369 VM_ENTRY_MARK; 370 ciEnv* env = CURRENT_ENV; 371 constantPoolHandle cpool(THREAD, _method->get_Method()->constants()); 372 ciMethod* m = env->get_method_by_index(cpool, get_method_index(), cur_bc(), _holder); 373 will_link = m->is_loaded(); 374 375 // Use the signature stored in the CP cache to create a signature 376 // with correct types (in respect to class loaders). 377 // 378 // In classic Java (before Java 7) there is never the slightest 379 // difference between the signature at the call site and that of the 380 // method. Such a difference would have been a type error in the 381 // JVM. 382 // 383 // Now there are a few circumstances where the signature of a call 384 // site (which controls the outgoing stacked arguments) can differ 385 // from the signature of the method (which controls the receipt of 386 // those arguments at the method entry point). 387 // 388 // A. The signatures can differ if the callee is a static method and 389 // the caller thinks it is calling a non-static method (VH.get). 390 // This requires the method signature to have an explicit leading 391 // argument for the implicit 'this', not present at the call site. 392 // 393 // B. The call site can have less specific parameter types than the 394 // method, allowing loosely-typed code to handle strongly-typed 395 // methods. This happens with linkToStatic and related linker 396 // commands. Obviously the loosely-typed code has to ensure that 397 // the strongly typed method's invariants are respected, and this is 398 // done by issuing dynamic casts. 399 // 400 // C. The call site can have more specific parameter types than the 401 // method, allowing loosely-typed methods to handle strongly-typed 402 // requests. 403 // 404 // D. There are corresponding effects with return values, such as 405 // boolean method returning an int to an int-receiving call site, 406 // even though the method thought it returned just a boolean. 407 // 408 // E. The calling sequence at a particular call site may add an 409 // "appendix" argument not mentioned in the call site signature. It 410 // is expected by the method signature, though, and this adds to the 411 // method's arity, even after 'this' parameter effects (A) are 412 // discounted. Appendixes are used by invokehandle and 413 // invokedynamic instructions. 414 // 415 // F. A linker method (linkToStatic, etc.) can also take an extra 416 // argument, a MemberName which routes the call to a concrete 417 // strongly-typed method. In this case the linker method may also 418 // differ in any of the ways A-D. The eventual method will ignore 419 // the presence of the extra argument. 420 // 421 // None of these changes to calling sequences requires an argument 422 // to be moved or reformatted in any way. This works because all 423 // references look alike to the JVM, as do all primitives (except 424 // float/long/double). Another required property of the JVM is 425 // that, if a trailing argument is added or dropped, the placement 426 // of other arguments does not change. This allows cases E and F to 427 // work smoothly, against without any moving or reformatting, 428 // despite the arity change. 429 // 430 if (has_local_signature()) { 431 Symbol* local_signature = cpool->symbol_at(get_method_signature_index(cpool)); 432 ciSymbol* sig_sym = env->get_symbol(local_signature); 433 ciKlass* pool_holder = env->get_klass(cpool->pool_holder()); 434 ciSignature* call_site_sig = new (env->arena()) ciSignature(pool_holder, cpool, sig_sym); 435 // Examples of how the call site signature can differ from the method's own signature: 436 // 437 // meth = static jboolean java.lang.invoke.VarHandleGuards.guard_LII_Z(jobject, jobject, jint, jint, jobject) 438 // msig = (Ljava/lang/invoke/VarHandle;Ljava/lang/Object;IILjava/lang/invoke/VarHandle$AccessDescriptor;)Z 439 // call = (Ljava/util/concurrent/locks/AbstractQueuedSynchronizer;II)Z 440 // 441 // meth = static jobject java.lang.invoke.LambdaForm$MH/0x0000000800066840.linkToTargetMethod(jobject, jobject) 442 // msig = (Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object; 443 // call = (Ljava/lang/String;)Ljava/util/function/Predicate; 444 // 445 (*declared_signature_result) = call_site_sig; 446 447 } else { 448 // We can just use the method's own signature. It may differ from the call site, but not by much. 449 // 450 // Examples of how the call site signature can differ from the method's signature: 451 // 452 // meth = static final native jint java.lang.invoke.MethodHandle.linkToStatic(jobject, jobject, jint, jint, jobject) 453 // msig = (Ljava/lang/Object;Ljava/lang/Object;IILjava/lang/invoke/MemberName;)I 454 // call = (Ljava/lang/invoke/VarHandle;Ljava/lang/Object;IILjava/lang/invoke/MemberName;)Z 455 // 456 // meth = final native jint java.lang.invoke.MethodHandle.invokeBasic(jobject, jobject, jint, jint) 457 // msig = (Ljava/lang/Object;Ljava/lang/Object;II)I 458 // call = (Ljava/lang/invoke/VarHandle;Ljava/lang/Object;II)Z 459 // 460 (*declared_signature_result) = m->signature(); 461 } 462 return m; 463 } 464 465 // ------------------------------------------------------------------ 466 // ciBytecodeStream::has_appendix 467 // 468 // Returns true if there is an appendix argument stored in the 469 // constant pool cache at the current bci. 470 bool ciBytecodeStream::has_appendix() { 471 VM_ENTRY_MARK; 472 constantPoolHandle cpool(THREAD, _method->get_Method()->constants()); 473 return ConstantPool::has_appendix_at_if_loaded(cpool, get_method_index()); 474 } 475 476 // ------------------------------------------------------------------ 477 // ciBytecodeStream::get_appendix 478 // 479 // Return the appendix argument stored in the constant pool cache at 480 // the current bci. 481 ciObject* ciBytecodeStream::get_appendix() { 482 VM_ENTRY_MARK; 483 constantPoolHandle cpool(THREAD, _method->get_Method()->constants()); 484 oop appendix_oop = ConstantPool::appendix_at_if_loaded(cpool, get_method_index()); 485 return CURRENT_ENV->get_object(appendix_oop); 486 } 487 488 // ------------------------------------------------------------------ 489 // ciBytecodeStream::has_local_signature 490 // 491 // Returns true if the method stored in the constant 492 // pool cache at the current bci has a local signature. 493 bool ciBytecodeStream::has_local_signature() { 494 GUARDED_VM_ENTRY( 495 constantPoolHandle cpool(Thread::current(), _method->get_Method()->constants()); 496 return ConstantPool::has_local_signature_at_if_loaded(cpool, get_method_index()); 497 ) 498 } 499 500 // ------------------------------------------------------------------ 501 // ciBytecodeStream::get_declared_method_holder 502 // 503 // Get the declared holder of the currently referenced method. 504 // 505 // Usage note: the holder() of a ciMethod class returns the canonical 506 // holder of the method, rather than the holder declared in the 507 // bytecodes. 508 // 509 // There is no "will_link" result passed back. The user is responsible 510 // for checking linkability when retrieving the associated method. 511 ciKlass* ciBytecodeStream::get_declared_method_holder() { 512 VM_ENTRY_MARK; 513 constantPoolHandle cpool(THREAD, _method->get_Method()->constants()); 514 bool ignore; 515 // report as MethodHandle for invokedynamic, which is syntactically classless 516 if (cur_bc() == Bytecodes::_invokedynamic) { 517 return CURRENT_ENV->MethodHandle_klass(); 518 } 519 return CURRENT_ENV->get_klass_by_index(cpool, get_method_holder_index(), ignore, _holder); 520 } 521 522 // ------------------------------------------------------------------ 523 // ciBytecodeStream::get_method_holder_index 524 // 525 // Get the constant pool index of the declared holder of the method 526 // referenced by the current bytecode. Used for generating 527 // deoptimization information. 528 int ciBytecodeStream::get_method_holder_index() { 529 ConstantPool* cpool = _method->get_Method()->constants(); 530 return cpool->klass_ref_index_at(get_method_index()); 531 } 532 533 // ------------------------------------------------------------------ 534 // ciBytecodeStream::get_method_signature_index 535 // 536 // Get the constant pool index of the signature of the method 537 // referenced by the current bytecode. Used for generating 538 // deoptimization information. 539 int ciBytecodeStream::get_method_signature_index(const constantPoolHandle& cpool) { 540 GUARDED_VM_ENTRY( 541 const int method_index = get_method_index(); 542 const int name_and_type_index = cpool->name_and_type_ref_index_at(method_index); 543 return cpool->signature_ref_index_at(name_and_type_index); 544 ) 545 } 546