1 /* 2 * Copyright (C) 2014 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #include "inline_method_analyser.h" 18 19 #include "art_field-inl.h" 20 #include "art_method-inl.h" 21 #include "class_linker-inl.h" 22 #include "dex_file-inl.h" 23 #include "dex_instruction.h" 24 #include "dex_instruction-inl.h" 25 #include "dex_instruction_utils.h" 26 #include "mirror/class-inl.h" 27 #include "mirror/dex_cache-inl.h" 28 #include "verifier/method_verifier-inl.h" 29 30 /* 31 * NOTE: This code is part of the quick compiler. It lives in the runtime 32 * only to allow the debugger to check whether a method has been inlined. 33 */ 34 35 namespace art { 36 37 namespace { // anonymous namespace 38 39 // Helper class for matching a pattern. 40 class Matcher { 41 public: 42 // Match function type. 43 typedef bool MatchFn(Matcher* matcher); 44 45 template <size_t size> 46 static bool Match(const DexFile::CodeItem* code_item, MatchFn* const (&pattern)[size]); 47 48 // Match and advance. 49 50 static bool Mark(Matcher* matcher); 51 52 template <bool (Matcher::*Fn)()> 53 static bool Required(Matcher* matcher); 54 55 template <bool (Matcher::*Fn)()> 56 static bool Repeated(Matcher* matcher); // On match, returns to the mark. 57 58 // Match an individual instruction. 59 60 template <Instruction::Code opcode> bool Opcode(); 61 bool Const0(); 62 bool IPutOnThis(); 63 64 private: 65 explicit Matcher(const DexFile::CodeItem* code_item) 66 : code_item_(code_item), 67 instruction_(Instruction::At(code_item->insns_)), 68 pos_(0u), 69 mark_(0u) { } 70 71 static bool DoMatch(const DexFile::CodeItem* code_item, MatchFn* const* pattern, size_t size); 72 73 const DexFile::CodeItem* const code_item_; 74 const Instruction* instruction_; 75 size_t pos_; 76 size_t mark_; 77 }; 78 79 template <size_t size> 80 bool Matcher::Match(const DexFile::CodeItem* code_item, MatchFn* const (&pattern)[size]) { 81 return DoMatch(code_item, pattern, size); 82 } 83 84 bool Matcher::Mark(Matcher* matcher) { 85 matcher->pos_ += 1u; // Advance to the next match function before marking. 86 matcher->mark_ = matcher->pos_; 87 return true; 88 } 89 90 template <bool (Matcher::*Fn)()> 91 bool Matcher::Required(Matcher* matcher) { 92 if (!(matcher->*Fn)()) { 93 return false; 94 } 95 matcher->pos_ += 1u; 96 matcher->instruction_ = matcher->instruction_->Next(); 97 return true; 98 } 99 100 template <bool (Matcher::*Fn)()> 101 bool Matcher::Repeated(Matcher* matcher) { 102 if (!(matcher->*Fn)()) { 103 // Didn't match optional instruction, try the next match function. 104 matcher->pos_ += 1u; 105 return true; 106 } 107 matcher->pos_ = matcher->mark_; 108 matcher->instruction_ = matcher->instruction_->Next(); 109 return true; 110 } 111 112 template <Instruction::Code opcode> 113 bool Matcher::Opcode() { 114 return instruction_->Opcode() == opcode; 115 } 116 117 // Match const 0. 118 bool Matcher::Const0() { 119 return IsInstructionDirectConst(instruction_->Opcode()) && 120 (instruction_->Opcode() == Instruction::CONST_WIDE ? instruction_->VRegB_51l() == 0 121 : instruction_->VRegB() == 0); 122 } 123 124 bool Matcher::IPutOnThis() { 125 DCHECK_NE(code_item_->ins_size_, 0u); 126 return IsInstructionIPut(instruction_->Opcode()) && 127 instruction_->VRegB_22c() == code_item_->registers_size_ - code_item_->ins_size_; 128 } 129 130 bool Matcher::DoMatch(const DexFile::CodeItem* code_item, MatchFn* const* pattern, size_t size) { 131 Matcher matcher(code_item); 132 while (matcher.pos_ != size) { 133 if (!pattern[matcher.pos_](&matcher)) { 134 return false; 135 } 136 } 137 return true; 138 } 139 140 // Used for a single invoke in a constructor. In that situation, the method verifier makes 141 // sure we invoke a constructor either in the same class or superclass with at least "this". 142 ArtMethod* GetTargetConstructor(ArtMethod* method, const Instruction* invoke_direct) 143 SHARED_REQUIRES(Locks::mutator_lock_) { 144 DCHECK_EQ(invoke_direct->Opcode(), Instruction::INVOKE_DIRECT); 145 DCHECK_EQ(invoke_direct->VRegC_35c(), 146 method->GetCodeItem()->registers_size_ - method->GetCodeItem()->ins_size_); 147 uint32_t method_index = invoke_direct->VRegB_35c(); 148 size_t pointer_size = Runtime::Current()->GetClassLinker()->GetImagePointerSize(); 149 ArtMethod* target_method = 150 method->GetDexCache()->GetResolvedMethod(method_index, pointer_size); 151 if (kIsDebugBuild && target_method != nullptr) { 152 CHECK(!target_method->IsStatic()); 153 CHECK(target_method->IsConstructor()); 154 CHECK(target_method->GetDeclaringClass() == method->GetDeclaringClass() || 155 target_method->GetDeclaringClass() == method->GetDeclaringClass()->GetSuperClass()); 156 } 157 return target_method; 158 } 159 160 // Return the forwarded arguments and check that all remaining arguments are zero. 161 // If the check fails, return static_cast<size_t>(-1). 162 size_t CountForwardedConstructorArguments(const DexFile::CodeItem* code_item, 163 const Instruction* invoke_direct, 164 uint16_t zero_vreg_mask) { 165 DCHECK_EQ(invoke_direct->Opcode(), Instruction::INVOKE_DIRECT); 166 size_t number_of_args = invoke_direct->VRegA_35c(); 167 DCHECK_NE(number_of_args, 0u); 168 uint32_t args[Instruction::kMaxVarArgRegs]; 169 invoke_direct->GetVarArgs(args); 170 uint16_t this_vreg = args[0]; 171 DCHECK_EQ(this_vreg, code_item->registers_size_ - code_item->ins_size_); // Checked by verifier. 172 size_t forwarded = 1u; 173 while (forwarded < number_of_args && 174 args[forwarded] == this_vreg + forwarded && 175 (zero_vreg_mask & (1u << args[forwarded])) == 0) { 176 ++forwarded; 177 } 178 for (size_t i = forwarded; i != number_of_args; ++i) { 179 if ((zero_vreg_mask & (1u << args[i])) == 0) { 180 return static_cast<size_t>(-1); 181 } 182 } 183 return forwarded; 184 } 185 186 uint16_t GetZeroVRegMask(const Instruction* const0) { 187 DCHECK(IsInstructionDirectConst(const0->Opcode())); 188 DCHECK((const0->Opcode() == Instruction::CONST_WIDE) ? const0->VRegB_51l() == 0u 189 : const0->VRegB() == 0); 190 uint16_t base_mask = IsInstructionConstWide(const0->Opcode()) ? 3u : 1u; 191 return base_mask << const0->VRegA(); 192 } 193 194 // We limit the number of IPUTs storing parameters. There can be any number 195 // of IPUTs that store the value 0 as they are useless in a constructor as 196 // the object always starts zero-initialized. We also eliminate all but the 197 // last store to any field as they are not observable; not even if the field 198 // is volatile as no reference to the object can escape from a constructor 199 // with this pattern. 200 static constexpr size_t kMaxConstructorIPuts = 3u; 201 202 struct ConstructorIPutData { 203 ConstructorIPutData() : field_index(DexFile::kDexNoIndex16), arg(0u) { } 204 205 uint16_t field_index; 206 uint16_t arg; 207 }; 208 209 bool RecordConstructorIPut(ArtMethod* method, 210 const Instruction* new_iput, 211 uint16_t this_vreg, 212 uint16_t zero_vreg_mask, 213 /*inout*/ ConstructorIPutData (&iputs)[kMaxConstructorIPuts]) 214 SHARED_REQUIRES(Locks::mutator_lock_) { 215 DCHECK(IsInstructionIPut(new_iput->Opcode())); 216 uint32_t field_index = new_iput->VRegC_22c(); 217 size_t pointer_size = Runtime::Current()->GetClassLinker()->GetImagePointerSize(); 218 mirror::DexCache* dex_cache = method->GetDexCache(); 219 ArtField* field = dex_cache->GetResolvedField(field_index, pointer_size); 220 if (UNLIKELY(field == nullptr)) { 221 return false; 222 } 223 // Remove previous IPUT to the same field, if any. Different field indexes may refer 224 // to the same field, so we need to compare resolved fields from the dex cache. 225 for (size_t old_pos = 0; old_pos != arraysize(iputs); ++old_pos) { 226 if (iputs[old_pos].field_index == DexFile::kDexNoIndex16) { 227 break; 228 } 229 ArtField* f = dex_cache->GetResolvedField(iputs[old_pos].field_index, pointer_size); 230 DCHECK(f != nullptr); 231 if (f == field) { 232 auto back_it = std::copy(iputs + old_pos + 1, iputs + arraysize(iputs), iputs + old_pos); 233 *back_it = ConstructorIPutData(); 234 break; 235 } 236 } 237 // If the stored value isn't zero, record the IPUT. 238 if ((zero_vreg_mask & (1u << new_iput->VRegA_22c())) == 0u) { 239 size_t new_pos = 0; 240 while (new_pos != arraysize(iputs) && iputs[new_pos].field_index != DexFile::kDexNoIndex16) { 241 ++new_pos; 242 } 243 if (new_pos == arraysize(iputs)) { 244 return false; // Exceeded capacity of the output array. 245 } 246 iputs[new_pos].field_index = field_index; 247 iputs[new_pos].arg = new_iput->VRegA_22c() - this_vreg; 248 } 249 return true; 250 } 251 252 bool DoAnalyseConstructor(const DexFile::CodeItem* code_item, 253 ArtMethod* method, 254 /*inout*/ ConstructorIPutData (&iputs)[kMaxConstructorIPuts]) 255 SHARED_REQUIRES(Locks::mutator_lock_) { 256 // On entry we should not have any IPUTs yet. 257 DCHECK_EQ(0, std::count_if( 258 iputs, 259 iputs + arraysize(iputs), 260 [](const ConstructorIPutData& iput_data) { 261 return iput_data.field_index != DexFile::kDexNoIndex16; 262 })); 263 264 // Limit the maximum number of code units we're willing to match. 265 static constexpr size_t kMaxCodeUnits = 16u; 266 267 // Limit the number of registers that the constructor may use to 16. 268 // Given that IPUTs must use low 16 registers and we do not match MOVEs, 269 // this is a reasonable limitation. 270 static constexpr size_t kMaxVRegs = 16u; 271 272 // We try to match a constructor that calls another constructor (either in 273 // superclass or in the same class) with the same parameters, or with some 274 // parameters truncated (allowed only for calls to superclass constructor) 275 // or with extra parameters with value 0 (with any type, including null). 276 // This call can be followed by optional IPUTs on "this" storing either one 277 // of the parameters or 0 and the code must then finish with RETURN_VOID. 278 // The called constructor must be either java.lang.Object.<init>() or it 279 // must also match the same pattern. 280 static Matcher::MatchFn* const kConstructorPattern[] = { 281 &Matcher::Mark, 282 &Matcher::Repeated<&Matcher::Const0>, 283 &Matcher::Required<&Matcher::Opcode<Instruction::INVOKE_DIRECT>>, 284 &Matcher::Mark, 285 &Matcher::Repeated<&Matcher::Const0>, 286 &Matcher::Repeated<&Matcher::IPutOnThis>, 287 &Matcher::Required<&Matcher::Opcode<Instruction::RETURN_VOID>>, 288 }; 289 290 DCHECK(method != nullptr); 291 DCHECK(!method->IsStatic()); 292 DCHECK(method->IsConstructor()); 293 DCHECK(code_item != nullptr); 294 if (!method->GetDeclaringClass()->IsVerified() || 295 code_item->insns_size_in_code_units_ > kMaxCodeUnits || 296 code_item->registers_size_ > kMaxVRegs || 297 !Matcher::Match(code_item, kConstructorPattern)) { 298 return false; 299 } 300 301 // Verify the invoke, prevent a few odd cases and collect IPUTs. 302 uint16_t this_vreg = code_item->registers_size_ - code_item->ins_size_; 303 uint16_t zero_vreg_mask = 0u; 304 for (const Instruction* instruction = Instruction::At(code_item->insns_); 305 instruction->Opcode() != Instruction::RETURN_VOID; 306 instruction = instruction->Next()) { 307 if (instruction->Opcode() == Instruction::INVOKE_DIRECT) { 308 ArtMethod* target_method = GetTargetConstructor(method, instruction); 309 if (target_method == nullptr) { 310 return false; 311 } 312 // We allow forwarding constructors only if they pass more arguments 313 // to prevent infinite recursion. 314 if (target_method->GetDeclaringClass() == method->GetDeclaringClass() && 315 instruction->VRegA_35c() <= code_item->ins_size_) { 316 return false; 317 } 318 size_t forwarded = CountForwardedConstructorArguments(code_item, instruction, zero_vreg_mask); 319 if (forwarded == static_cast<size_t>(-1)) { 320 return false; 321 } 322 if (target_method->GetDeclaringClass()->IsObjectClass()) { 323 DCHECK_EQ(Instruction::At(target_method->GetCodeItem()->insns_)->Opcode(), 324 Instruction::RETURN_VOID); 325 } else { 326 const DexFile::CodeItem* target_code_item = target_method->GetCodeItem(); 327 if (target_code_item == nullptr) { 328 return false; // Native constructor? 329 } 330 if (!DoAnalyseConstructor(target_code_item, target_method, iputs)) { 331 return false; 332 } 333 // Prune IPUTs with zero input. 334 auto kept_end = std::remove_if( 335 iputs, 336 iputs + arraysize(iputs), 337 [forwarded](const ConstructorIPutData& iput_data) { 338 return iput_data.arg >= forwarded; 339 }); 340 std::fill(kept_end, iputs + arraysize(iputs), ConstructorIPutData()); 341 // If we have any IPUTs from the call, check that the target method is in the same 342 // dex file (compare DexCache references), otherwise field_indexes would be bogus. 343 if (iputs[0].field_index != DexFile::kDexNoIndex16 && 344 target_method->GetDexCache() != method->GetDexCache()) { 345 return false; 346 } 347 } 348 } else if (IsInstructionDirectConst(instruction->Opcode())) { 349 zero_vreg_mask |= GetZeroVRegMask(instruction); 350 if ((zero_vreg_mask & (1u << this_vreg)) != 0u) { 351 return false; // Overwriting `this` is unsupported. 352 } 353 } else { 354 DCHECK(IsInstructionIPut(instruction->Opcode())); 355 DCHECK_EQ(instruction->VRegB_22c(), this_vreg); 356 if (!RecordConstructorIPut(method, instruction, this_vreg, zero_vreg_mask, iputs)) { 357 return false; 358 } 359 } 360 } 361 return true; 362 } 363 364 } // anonymous namespace 365 366 bool AnalyseConstructor(const DexFile::CodeItem* code_item, 367 ArtMethod* method, 368 InlineMethod* result) 369 SHARED_REQUIRES(Locks::mutator_lock_) { 370 ConstructorIPutData iputs[kMaxConstructorIPuts]; 371 if (!DoAnalyseConstructor(code_item, method, iputs)) { 372 return false; 373 } 374 static_assert(kMaxConstructorIPuts == 3, "Unexpected limit"); // Code below depends on this. 375 DCHECK(iputs[0].field_index != DexFile::kDexNoIndex16 || 376 iputs[1].field_index == DexFile::kDexNoIndex16); 377 DCHECK(iputs[1].field_index != DexFile::kDexNoIndex16 || 378 iputs[2].field_index == DexFile::kDexNoIndex16); 379 380 #define STORE_IPUT(n) \ 381 do { \ 382 result->d.constructor_data.iput##n##_field_index = iputs[n].field_index; \ 383 result->d.constructor_data.iput##n##_arg = iputs[n].arg; \ 384 } while (false) 385 386 STORE_IPUT(0); 387 STORE_IPUT(1); 388 STORE_IPUT(2); 389 #undef STORE_IPUT 390 391 result->opcode = kInlineOpConstructor; 392 result->flags = kInlineSpecial; 393 result->d.constructor_data.reserved = 0u; 394 return true; 395 } 396 397 static_assert(InlineMethodAnalyser::IsInstructionIGet(Instruction::IGET), "iget type"); 398 static_assert(InlineMethodAnalyser::IsInstructionIGet(Instruction::IGET_WIDE), "iget_wide type"); 399 static_assert(InlineMethodAnalyser::IsInstructionIGet(Instruction::IGET_OBJECT), 400 "iget_object type"); 401 static_assert(InlineMethodAnalyser::IsInstructionIGet(Instruction::IGET_BOOLEAN), 402 "iget_boolean type"); 403 static_assert(InlineMethodAnalyser::IsInstructionIGet(Instruction::IGET_BYTE), "iget_byte type"); 404 static_assert(InlineMethodAnalyser::IsInstructionIGet(Instruction::IGET_CHAR), "iget_char type"); 405 static_assert(InlineMethodAnalyser::IsInstructionIGet(Instruction::IGET_SHORT), "iget_short type"); 406 static_assert(InlineMethodAnalyser::IsInstructionIPut(Instruction::IPUT), "iput type"); 407 static_assert(InlineMethodAnalyser::IsInstructionIPut(Instruction::IPUT_WIDE), "iput_wide type"); 408 static_assert(InlineMethodAnalyser::IsInstructionIPut(Instruction::IPUT_OBJECT), 409 "iput_object type"); 410 static_assert(InlineMethodAnalyser::IsInstructionIPut(Instruction::IPUT_BOOLEAN), 411 "iput_boolean type"); 412 static_assert(InlineMethodAnalyser::IsInstructionIPut(Instruction::IPUT_BYTE), "iput_byte type"); 413 static_assert(InlineMethodAnalyser::IsInstructionIPut(Instruction::IPUT_CHAR), "iput_char type"); 414 static_assert(InlineMethodAnalyser::IsInstructionIPut(Instruction::IPUT_SHORT), "iput_short type"); 415 static_assert(InlineMethodAnalyser::IGetVariant(Instruction::IGET) == 416 InlineMethodAnalyser::IPutVariant(Instruction::IPUT), "iget/iput variant"); 417 static_assert(InlineMethodAnalyser::IGetVariant(Instruction::IGET_WIDE) == 418 InlineMethodAnalyser::IPutVariant(Instruction::IPUT_WIDE), "iget/iput_wide variant"); 419 static_assert(InlineMethodAnalyser::IGetVariant(Instruction::IGET_OBJECT) == 420 InlineMethodAnalyser::IPutVariant(Instruction::IPUT_OBJECT), "iget/iput_object variant"); 421 static_assert(InlineMethodAnalyser::IGetVariant(Instruction::IGET_BOOLEAN) == 422 InlineMethodAnalyser::IPutVariant(Instruction::IPUT_BOOLEAN), "iget/iput_boolean variant"); 423 static_assert(InlineMethodAnalyser::IGetVariant(Instruction::IGET_BYTE) == 424 InlineMethodAnalyser::IPutVariant(Instruction::IPUT_BYTE), "iget/iput_byte variant"); 425 static_assert(InlineMethodAnalyser::IGetVariant(Instruction::IGET_CHAR) == 426 InlineMethodAnalyser::IPutVariant(Instruction::IPUT_CHAR), "iget/iput_char variant"); 427 static_assert(InlineMethodAnalyser::IGetVariant(Instruction::IGET_SHORT) == 428 InlineMethodAnalyser::IPutVariant(Instruction::IPUT_SHORT), "iget/iput_short variant"); 429 430 // This is used by compiler and debugger. We look into the dex cache for resolved methods and 431 // fields. However, in the context of the debugger, not all methods and fields are resolved. Since 432 // we need to be able to detect possibly inlined method, we pass a null inline method to indicate 433 // we don't want to take unresolved methods and fields into account during analysis. 434 bool InlineMethodAnalyser::AnalyseMethodCode(verifier::MethodVerifier* verifier, 435 InlineMethod* result) { 436 DCHECK(verifier != nullptr); 437 if (!Runtime::Current()->UseJitCompilation()) { 438 DCHECK_EQ(verifier->CanLoadClasses(), result != nullptr); 439 } 440 441 // Note: verifier->GetMethod() may be null. 442 return AnalyseMethodCode(verifier->CodeItem(), 443 verifier->GetMethodReference(), 444 (verifier->GetAccessFlags() & kAccStatic) != 0u, 445 verifier->GetMethod(), 446 result); 447 } 448 449 bool InlineMethodAnalyser::AnalyseMethodCode(ArtMethod* method, InlineMethod* result) { 450 const DexFile::CodeItem* code_item = method->GetCodeItem(); 451 if (code_item == nullptr) { 452 // Native or abstract. 453 return false; 454 } 455 return AnalyseMethodCode( 456 code_item, method->ToMethodReference(), method->IsStatic(), method, result); 457 } 458 459 bool InlineMethodAnalyser::AnalyseMethodCode(const DexFile::CodeItem* code_item, 460 const MethodReference& method_ref, 461 bool is_static, 462 ArtMethod* method, 463 InlineMethod* result) { 464 // We currently support only plain return or 2-instruction methods. 465 466 DCHECK_NE(code_item->insns_size_in_code_units_, 0u); 467 const Instruction* instruction = Instruction::At(code_item->insns_); 468 Instruction::Code opcode = instruction->Opcode(); 469 470 switch (opcode) { 471 case Instruction::RETURN_VOID: 472 if (result != nullptr) { 473 result->opcode = kInlineOpNop; 474 result->flags = kInlineSpecial; 475 result->d.data = 0u; 476 } 477 return true; 478 case Instruction::RETURN: 479 case Instruction::RETURN_OBJECT: 480 case Instruction::RETURN_WIDE: 481 return AnalyseReturnMethod(code_item, result); 482 case Instruction::CONST: 483 case Instruction::CONST_4: 484 case Instruction::CONST_16: 485 case Instruction::CONST_HIGH16: 486 // TODO: Support wide constants (RETURN_WIDE). 487 if (AnalyseConstMethod(code_item, result)) { 488 return true; 489 } 490 FALLTHROUGH_INTENDED; 491 case Instruction::CONST_WIDE: 492 case Instruction::CONST_WIDE_16: 493 case Instruction::CONST_WIDE_32: 494 case Instruction::CONST_WIDE_HIGH16: 495 case Instruction::INVOKE_DIRECT: 496 if (method != nullptr && !method->IsStatic() && method->IsConstructor()) { 497 return AnalyseConstructor(code_item, method, result); 498 } 499 return false; 500 case Instruction::IGET: 501 case Instruction::IGET_OBJECT: 502 case Instruction::IGET_BOOLEAN: 503 case Instruction::IGET_BYTE: 504 case Instruction::IGET_CHAR: 505 case Instruction::IGET_SHORT: 506 case Instruction::IGET_WIDE: 507 // TODO: Add handling for JIT. 508 // case Instruction::IGET_QUICK: 509 // case Instruction::IGET_WIDE_QUICK: 510 // case Instruction::IGET_OBJECT_QUICK: 511 return AnalyseIGetMethod(code_item, method_ref, is_static, method, result); 512 case Instruction::IPUT: 513 case Instruction::IPUT_OBJECT: 514 case Instruction::IPUT_BOOLEAN: 515 case Instruction::IPUT_BYTE: 516 case Instruction::IPUT_CHAR: 517 case Instruction::IPUT_SHORT: 518 case Instruction::IPUT_WIDE: 519 // TODO: Add handling for JIT. 520 // case Instruction::IPUT_QUICK: 521 // case Instruction::IPUT_WIDE_QUICK: 522 // case Instruction::IPUT_OBJECT_QUICK: 523 return AnalyseIPutMethod(code_item, method_ref, is_static, method, result); 524 default: 525 return false; 526 } 527 } 528 529 bool InlineMethodAnalyser::IsSyntheticAccessor(MethodReference ref) { 530 const DexFile::MethodId& method_id = ref.dex_file->GetMethodId(ref.dex_method_index); 531 const char* method_name = ref.dex_file->GetMethodName(method_id); 532 // javac names synthetic accessors "access$nnn", 533 // jack names them "-getN", "-putN", "-wrapN". 534 return strncmp(method_name, "access$", strlen("access$")) == 0 || 535 strncmp(method_name, "-", strlen("-")) == 0; 536 } 537 538 bool InlineMethodAnalyser::AnalyseReturnMethod(const DexFile::CodeItem* code_item, 539 InlineMethod* result) { 540 const Instruction* return_instruction = Instruction::At(code_item->insns_); 541 Instruction::Code return_opcode = return_instruction->Opcode(); 542 uint32_t reg = return_instruction->VRegA_11x(); 543 uint32_t arg_start = code_item->registers_size_ - code_item->ins_size_; 544 DCHECK_GE(reg, arg_start); 545 DCHECK_LT((return_opcode == Instruction::RETURN_WIDE) ? reg + 1 : reg, 546 code_item->registers_size_); 547 548 if (result != nullptr) { 549 result->opcode = kInlineOpReturnArg; 550 result->flags = kInlineSpecial; 551 InlineReturnArgData* data = &result->d.return_data; 552 data->arg = reg - arg_start; 553 data->is_wide = (return_opcode == Instruction::RETURN_WIDE) ? 1u : 0u; 554 data->is_object = (return_opcode == Instruction::RETURN_OBJECT) ? 1u : 0u; 555 data->reserved = 0u; 556 data->reserved2 = 0u; 557 } 558 return true; 559 } 560 561 bool InlineMethodAnalyser::AnalyseConstMethod(const DexFile::CodeItem* code_item, 562 InlineMethod* result) { 563 const Instruction* instruction = Instruction::At(code_item->insns_); 564 const Instruction* return_instruction = instruction->Next(); 565 Instruction::Code return_opcode = return_instruction->Opcode(); 566 if (return_opcode != Instruction::RETURN && 567 return_opcode != Instruction::RETURN_OBJECT) { 568 return false; 569 } 570 571 int32_t return_reg = return_instruction->VRegA_11x(); 572 DCHECK_LT(return_reg, code_item->registers_size_); 573 574 int32_t const_value = instruction->VRegB(); 575 if (instruction->Opcode() == Instruction::CONST_HIGH16) { 576 const_value <<= 16; 577 } 578 DCHECK_LT(instruction->VRegA(), code_item->registers_size_); 579 if (instruction->VRegA() != return_reg) { 580 return false; // Not returning the value set by const? 581 } 582 if (return_opcode == Instruction::RETURN_OBJECT && const_value != 0) { 583 return false; // Returning non-null reference constant? 584 } 585 if (result != nullptr) { 586 result->opcode = kInlineOpNonWideConst; 587 result->flags = kInlineSpecial; 588 result->d.data = static_cast<uint64_t>(const_value); 589 } 590 return true; 591 } 592 593 bool InlineMethodAnalyser::AnalyseIGetMethod(const DexFile::CodeItem* code_item, 594 const MethodReference& method_ref, 595 bool is_static, 596 ArtMethod* method, 597 InlineMethod* result) { 598 const Instruction* instruction = Instruction::At(code_item->insns_); 599 Instruction::Code opcode = instruction->Opcode(); 600 DCHECK(IsInstructionIGet(opcode)); 601 602 const Instruction* return_instruction = instruction->Next(); 603 Instruction::Code return_opcode = return_instruction->Opcode(); 604 if (!(return_opcode == Instruction::RETURN_WIDE && opcode == Instruction::IGET_WIDE) && 605 !(return_opcode == Instruction::RETURN_OBJECT && opcode == Instruction::IGET_OBJECT) && 606 !(return_opcode == Instruction::RETURN && opcode != Instruction::IGET_WIDE && 607 opcode != Instruction::IGET_OBJECT)) { 608 return false; 609 } 610 611 uint32_t return_reg = return_instruction->VRegA_11x(); 612 DCHECK_LT(return_opcode == Instruction::RETURN_WIDE ? return_reg + 1 : return_reg, 613 code_item->registers_size_); 614 615 uint32_t dst_reg = instruction->VRegA_22c(); 616 uint32_t object_reg = instruction->VRegB_22c(); 617 uint32_t field_idx = instruction->VRegC_22c(); 618 uint32_t arg_start = code_item->registers_size_ - code_item->ins_size_; 619 DCHECK_GE(object_reg, arg_start); 620 DCHECK_LT(object_reg, code_item->registers_size_); 621 uint32_t object_arg = object_reg - arg_start; 622 623 DCHECK_LT(opcode == Instruction::IGET_WIDE ? dst_reg + 1 : dst_reg, code_item->registers_size_); 624 if (dst_reg != return_reg) { 625 return false; // Not returning the value retrieved by IGET? 626 } 627 628 if (is_static || object_arg != 0u) { 629 // TODO: Implement inlining of IGET on non-"this" registers (needs correct stack trace for NPE). 630 // Allow synthetic accessors. We don't care about losing their stack frame in NPE. 631 if (!IsSyntheticAccessor(method_ref)) { 632 return false; 633 } 634 } 635 636 // InlineIGetIPutData::object_arg is only 4 bits wide. 637 static constexpr uint16_t kMaxObjectArg = 15u; 638 if (object_arg > kMaxObjectArg) { 639 return false; 640 } 641 642 if (result != nullptr) { 643 InlineIGetIPutData* data = &result->d.ifield_data; 644 if (!ComputeSpecialAccessorInfo(method, field_idx, false, data)) { 645 return false; 646 } 647 result->opcode = kInlineOpIGet; 648 result->flags = kInlineSpecial; 649 data->op_variant = IGetVariant(opcode); 650 data->method_is_static = is_static ? 1u : 0u; 651 data->object_arg = object_arg; // Allow IGET on any register, not just "this". 652 data->src_arg = 0u; 653 data->return_arg_plus1 = 0u; 654 } 655 return true; 656 } 657 658 bool InlineMethodAnalyser::AnalyseIPutMethod(const DexFile::CodeItem* code_item, 659 const MethodReference& method_ref, 660 bool is_static, 661 ArtMethod* method, 662 InlineMethod* result) { 663 const Instruction* instruction = Instruction::At(code_item->insns_); 664 Instruction::Code opcode = instruction->Opcode(); 665 DCHECK(IsInstructionIPut(opcode)); 666 667 const Instruction* return_instruction = instruction->Next(); 668 Instruction::Code return_opcode = return_instruction->Opcode(); 669 uint32_t arg_start = code_item->registers_size_ - code_item->ins_size_; 670 uint16_t return_arg_plus1 = 0u; 671 if (return_opcode != Instruction::RETURN_VOID) { 672 if (return_opcode != Instruction::RETURN && 673 return_opcode != Instruction::RETURN_OBJECT && 674 return_opcode != Instruction::RETURN_WIDE) { 675 return false; 676 } 677 // Returning an argument. 678 uint32_t return_reg = return_instruction->VRegA_11x(); 679 DCHECK_GE(return_reg, arg_start); 680 DCHECK_LT(return_opcode == Instruction::RETURN_WIDE ? return_reg + 1u : return_reg, 681 code_item->registers_size_); 682 return_arg_plus1 = return_reg - arg_start + 1u; 683 } 684 685 uint32_t src_reg = instruction->VRegA_22c(); 686 uint32_t object_reg = instruction->VRegB_22c(); 687 uint32_t field_idx = instruction->VRegC_22c(); 688 DCHECK_GE(object_reg, arg_start); 689 DCHECK_LT(object_reg, code_item->registers_size_); 690 DCHECK_GE(src_reg, arg_start); 691 DCHECK_LT(opcode == Instruction::IPUT_WIDE ? src_reg + 1 : src_reg, code_item->registers_size_); 692 uint32_t object_arg = object_reg - arg_start; 693 uint32_t src_arg = src_reg - arg_start; 694 695 if (is_static || object_arg != 0u) { 696 // TODO: Implement inlining of IPUT on non-"this" registers (needs correct stack trace for NPE). 697 // Allow synthetic accessors. We don't care about losing their stack frame in NPE. 698 if (!IsSyntheticAccessor(method_ref)) { 699 return false; 700 } 701 } 702 703 // InlineIGetIPutData::object_arg/src_arg/return_arg_plus1 are each only 4 bits wide. 704 static constexpr uint16_t kMaxObjectArg = 15u; 705 static constexpr uint16_t kMaxSrcArg = 15u; 706 static constexpr uint16_t kMaxReturnArgPlus1 = 15u; 707 if (object_arg > kMaxObjectArg || src_arg > kMaxSrcArg || return_arg_plus1 > kMaxReturnArgPlus1) { 708 return false; 709 } 710 711 if (result != nullptr) { 712 InlineIGetIPutData* data = &result->d.ifield_data; 713 if (!ComputeSpecialAccessorInfo(method, field_idx, true, data)) { 714 return false; 715 } 716 result->opcode = kInlineOpIPut; 717 result->flags = kInlineSpecial; 718 data->op_variant = IPutVariant(opcode); 719 data->method_is_static = is_static ? 1u : 0u; 720 data->object_arg = object_arg; // Allow IPUT on any register, not just "this". 721 data->src_arg = src_arg; 722 data->return_arg_plus1 = return_arg_plus1; 723 } 724 return true; 725 } 726 727 bool InlineMethodAnalyser::ComputeSpecialAccessorInfo(ArtMethod* method, 728 uint32_t field_idx, 729 bool is_put, 730 InlineIGetIPutData* result) { 731 if (method == nullptr) { 732 return false; 733 } 734 mirror::DexCache* dex_cache = method->GetDexCache(); 735 size_t pointer_size = Runtime::Current()->GetClassLinker()->GetImagePointerSize(); 736 ArtField* field = dex_cache->GetResolvedField(field_idx, pointer_size); 737 if (field == nullptr || field->IsStatic()) { 738 return false; 739 } 740 mirror::Class* method_class = method->GetDeclaringClass(); 741 mirror::Class* field_class = field->GetDeclaringClass(); 742 if (!method_class->CanAccessResolvedField(field_class, field, dex_cache, field_idx) || 743 (is_put && field->IsFinal() && method_class != field_class)) { 744 return false; 745 } 746 DCHECK_GE(field->GetOffset().Int32Value(), 0); 747 // Do not interleave function calls with bit field writes to placate valgrind. Bug: 27552451. 748 uint32_t field_offset = field->GetOffset().Uint32Value(); 749 bool is_volatile = field->IsVolatile(); 750 result->field_idx = field_idx; 751 result->field_offset = field_offset; 752 result->is_volatile = is_volatile ? 1u : 0u; 753 return true; 754 } 755 756 } // namespace art 757
