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