| /* |
| * Copyright (C) 2014 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #include "verified_method.h" |
| |
| #include <algorithm> |
| #include <memory> |
| #include <vector> |
| |
| #include "art_method-inl.h" |
| #include "base/enums.h" |
| #include "base/logging.h" |
| #include "base/stl_util.h" |
| #include "dex_file.h" |
| #include "dex_instruction-inl.h" |
| #include "dex_instruction_utils.h" |
| #include "mirror/class-inl.h" |
| #include "mirror/dex_cache-inl.h" |
| #include "mirror/object-inl.h" |
| #include "utils.h" |
| #include "verifier/method_verifier-inl.h" |
| #include "verifier/reg_type-inl.h" |
| #include "verifier/register_line-inl.h" |
| |
| namespace art { |
| |
| VerifiedMethod::VerifiedMethod(uint32_t encountered_error_types, bool has_runtime_throw) |
| : encountered_error_types_(encountered_error_types), |
| has_runtime_throw_(has_runtime_throw) { |
| } |
| |
| const VerifiedMethod* VerifiedMethod::Create(verifier::MethodVerifier* method_verifier, |
| bool compile) { |
| std::unique_ptr<VerifiedMethod> verified_method( |
| new VerifiedMethod(method_verifier->GetEncounteredFailureTypes(), |
| method_verifier->HasInstructionThatWillThrow())); |
| |
| if (compile) { |
| // TODO: move this out when DEX-to-DEX supports devirtualization. |
| if (method_verifier->HasVirtualOrInterfaceInvokes()) { |
| verified_method->GenerateDevirtMap(method_verifier); |
| } |
| |
| // Only need dequicken info for JIT so far. |
| if (Runtime::Current()->UseJitCompilation() && |
| !verified_method->GenerateDequickenMap(method_verifier)) { |
| return nullptr; |
| } |
| } |
| |
| if (method_verifier->HasCheckCasts()) { |
| verified_method->GenerateSafeCastSet(method_verifier); |
| } |
| |
| return verified_method.release(); |
| } |
| |
| const MethodReference* VerifiedMethod::GetDevirtTarget(uint32_t dex_pc) const { |
| auto it = devirt_map_.find(dex_pc); |
| return (it != devirt_map_.end()) ? &it->second : nullptr; |
| } |
| |
| const DexFileReference* VerifiedMethod::GetDequickenIndex(uint32_t dex_pc) const { |
| DCHECK(Runtime::Current()->UseJitCompilation()); |
| auto it = dequicken_map_.find(dex_pc); |
| return (it != dequicken_map_.end()) ? &it->second : nullptr; |
| } |
| |
| bool VerifiedMethod::IsSafeCast(uint32_t pc) const { |
| return std::binary_search(safe_cast_set_.begin(), safe_cast_set_.end(), pc); |
| } |
| |
| bool VerifiedMethod::GenerateDequickenMap(verifier::MethodVerifier* method_verifier) { |
| if (method_verifier->HasFailures()) { |
| return false; |
| } |
| const DexFile::CodeItem* code_item = method_verifier->CodeItem(); |
| const uint16_t* insns = code_item->insns_; |
| const Instruction* inst = Instruction::At(insns); |
| const Instruction* end = Instruction::At(insns + code_item->insns_size_in_code_units_); |
| for (; inst < end; inst = inst->Next()) { |
| const bool is_virtual_quick = inst->Opcode() == Instruction::INVOKE_VIRTUAL_QUICK; |
| const bool is_range_quick = inst->Opcode() == Instruction::INVOKE_VIRTUAL_RANGE_QUICK; |
| if (is_virtual_quick || is_range_quick) { |
| uint32_t dex_pc = inst->GetDexPc(insns); |
| verifier::RegisterLine* line = method_verifier->GetRegLine(dex_pc); |
| ArtMethod* method = |
| method_verifier->GetQuickInvokedMethod(inst, line, is_range_quick, true); |
| if (method == nullptr) { |
| // It can be null if the line wasn't verified since it was unreachable. |
| return false; |
| } |
| // The verifier must know what the type of the object was or else we would have gotten a |
| // failure. Put the dex method index in the dequicken map since we need this to get number of |
| // arguments in the compiler. |
| dequicken_map_.Put(dex_pc, DexFileReference(method->GetDexFile(), |
| method->GetDexMethodIndex())); |
| } else if (IsInstructionIGetQuickOrIPutQuick(inst->Opcode())) { |
| uint32_t dex_pc = inst->GetDexPc(insns); |
| verifier::RegisterLine* line = method_verifier->GetRegLine(dex_pc); |
| ArtField* field = method_verifier->GetQuickFieldAccess(inst, line); |
| if (field == nullptr) { |
| // It can be null if the line wasn't verified since it was unreachable. |
| return false; |
| } |
| // The verifier must know what the type of the field was or else we would have gotten a |
| // failure. Put the dex field index in the dequicken map since we need this for lowering |
| // in the compiler. |
| // TODO: Putting a field index in a method reference is gross. |
| dequicken_map_.Put(dex_pc, DexFileReference(field->GetDexFile(), field->GetDexFieldIndex())); |
| } |
| } |
| return true; |
| } |
| |
| void VerifiedMethod::GenerateDevirtMap(verifier::MethodVerifier* method_verifier) { |
| // It is risky to rely on reg_types for sharpening in cases of soft |
| // verification, we might end up sharpening to a wrong implementation. Just abort. |
| if (method_verifier->HasFailures()) { |
| return; |
| } |
| |
| const DexFile::CodeItem* code_item = method_verifier->CodeItem(); |
| const uint16_t* insns = code_item->insns_; |
| const Instruction* inst = Instruction::At(insns); |
| const Instruction* end = Instruction::At(insns + code_item->insns_size_in_code_units_); |
| |
| for (; inst < end; inst = inst->Next()) { |
| const bool is_virtual = inst->Opcode() == Instruction::INVOKE_VIRTUAL || |
| inst->Opcode() == Instruction::INVOKE_VIRTUAL_RANGE; |
| const bool is_interface = inst->Opcode() == Instruction::INVOKE_INTERFACE || |
| inst->Opcode() == Instruction::INVOKE_INTERFACE_RANGE; |
| |
| if (!is_interface && !is_virtual) { |
| continue; |
| } |
| // Get reg type for register holding the reference to the object that will be dispatched upon. |
| uint32_t dex_pc = inst->GetDexPc(insns); |
| verifier::RegisterLine* line = method_verifier->GetRegLine(dex_pc); |
| const bool is_range = inst->Opcode() == Instruction::INVOKE_VIRTUAL_RANGE || |
| inst->Opcode() == Instruction::INVOKE_INTERFACE_RANGE; |
| const verifier::RegType& |
| reg_type(line->GetRegisterType(method_verifier, |
| is_range ? inst->VRegC_3rc() : inst->VRegC_35c())); |
| |
| if (!reg_type.HasClass()) { |
| // We will compute devirtualization information only when we know the Class of the reg type. |
| continue; |
| } |
| mirror::Class* reg_class = reg_type.GetClass(); |
| if (reg_class->IsInterface()) { |
| // We can't devirtualize when the known type of the register is an interface. |
| continue; |
| } |
| if (reg_class->IsAbstract() && !reg_class->IsArrayClass()) { |
| // We can't devirtualize abstract classes except on arrays of abstract classes. |
| continue; |
| } |
| auto* cl = Runtime::Current()->GetClassLinker(); |
| PointerSize pointer_size = cl->GetImagePointerSize(); |
| ArtMethod* abstract_method = method_verifier->GetDexCache()->GetResolvedMethod( |
| is_range ? inst->VRegB_3rc() : inst->VRegB_35c(), pointer_size); |
| if (abstract_method == nullptr) { |
| // If the method is not found in the cache this means that it was never found |
| // by ResolveMethodAndCheckAccess() called when verifying invoke_*. |
| continue; |
| } |
| // Find the concrete method. |
| ArtMethod* concrete_method = nullptr; |
| if (is_interface) { |
| concrete_method = reg_type.GetClass()->FindVirtualMethodForInterface( |
| abstract_method, pointer_size); |
| } |
| if (is_virtual) { |
| concrete_method = reg_type.GetClass()->FindVirtualMethodForVirtual( |
| abstract_method, pointer_size); |
| } |
| if (concrete_method == nullptr || !concrete_method->IsInvokable()) { |
| // In cases where concrete_method is not found, or is not invokable, continue to the next |
| // invoke. |
| continue; |
| } |
| if (reg_type.IsPreciseReference() || concrete_method->IsFinal() || |
| concrete_method->GetDeclaringClass()->IsFinal()) { |
| // If we knew exactly the class being dispatched upon, or if the target method cannot be |
| // overridden record the target to be used in the compiler driver. |
| devirt_map_.Put(dex_pc, concrete_method->ToMethodReference()); |
| } |
| } |
| } |
| |
| void VerifiedMethod::GenerateSafeCastSet(verifier::MethodVerifier* method_verifier) { |
| /* |
| * Walks over the method code and adds any cast instructions in which |
| * the type cast is implicit to a set, which is used in the code generation |
| * to elide these casts. |
| */ |
| if (method_verifier->HasFailures()) { |
| return; |
| } |
| const DexFile::CodeItem* code_item = method_verifier->CodeItem(); |
| const Instruction* inst = Instruction::At(code_item->insns_); |
| const Instruction* end = Instruction::At(code_item->insns_ + |
| code_item->insns_size_in_code_units_); |
| |
| for (; inst < end; inst = inst->Next()) { |
| Instruction::Code code = inst->Opcode(); |
| if ((code == Instruction::CHECK_CAST) || (code == Instruction::APUT_OBJECT)) { |
| uint32_t dex_pc = inst->GetDexPc(code_item->insns_); |
| if (!method_verifier->GetInstructionFlags(dex_pc).IsVisited()) { |
| // Do not attempt to quicken this instruction, it's unreachable anyway. |
| continue; |
| } |
| const verifier::RegisterLine* line = method_verifier->GetRegLine(dex_pc); |
| bool is_safe_cast = false; |
| if (code == Instruction::CHECK_CAST) { |
| const verifier::RegType& reg_type(line->GetRegisterType(method_verifier, |
| inst->VRegA_21c())); |
| const verifier::RegType& cast_type = |
| method_verifier->ResolveCheckedClass(inst->VRegB_21c()); |
| is_safe_cast = cast_type.IsStrictlyAssignableFrom(reg_type); |
| } else { |
| const verifier::RegType& array_type(line->GetRegisterType(method_verifier, |
| inst->VRegB_23x())); |
| // We only know its safe to assign to an array if the array type is precise. For example, |
| // an Object[] can have any type of object stored in it, but it may also be assigned a |
| // String[] in which case the stores need to be of Strings. |
| if (array_type.IsPreciseReference()) { |
| const verifier::RegType& value_type(line->GetRegisterType(method_verifier, |
| inst->VRegA_23x())); |
| const verifier::RegType& component_type = method_verifier->GetRegTypeCache() |
| ->GetComponentType(array_type, method_verifier->GetClassLoader()); |
| is_safe_cast = component_type.IsStrictlyAssignableFrom(value_type); |
| } |
| } |
| if (is_safe_cast) { |
| // Verify ordering for push_back() to the sorted vector. |
| DCHECK(safe_cast_set_.empty() || safe_cast_set_.back() < dex_pc); |
| safe_cast_set_.push_back(dex_pc); |
| } |
| } |
| } |
| } |
| |
| } // namespace art |