112 lines
4.4 KiB
C++
112 lines
4.4 KiB
C++
/*
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* Copyright (C) 2014 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "verified_method.h"
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#include <algorithm>
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#include <memory>
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#include "base/logging.h"
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#include "dex_file.h"
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#include "dex_instruction-inl.h"
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#include "runtime.h"
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#include "verifier/method_verifier-inl.h"
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#include "verifier/reg_type-inl.h"
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#include "verifier/register_line-inl.h"
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#include "verifier/verifier_deps.h"
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namespace art {
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VerifiedMethod::VerifiedMethod(uint32_t encountered_error_types, bool has_runtime_throw)
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: encountered_error_types_(encountered_error_types),
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has_runtime_throw_(has_runtime_throw) {
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}
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const VerifiedMethod* VerifiedMethod::Create(verifier::MethodVerifier* method_verifier) {
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DCHECK(Runtime::Current()->IsAotCompiler());
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std::unique_ptr<VerifiedMethod> verified_method(
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new VerifiedMethod(method_verifier->GetEncounteredFailureTypes(),
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method_verifier->HasInstructionThatWillThrow()));
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if (method_verifier->HasCheckCasts()) {
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verified_method->GenerateSafeCastSet(method_verifier);
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}
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return verified_method.release();
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}
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bool VerifiedMethod::IsSafeCast(uint32_t pc) const {
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if (safe_cast_set_ == nullptr) {
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return false;
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}
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return std::binary_search(safe_cast_set_->begin(), safe_cast_set_->end(), pc);
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}
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void VerifiedMethod::GenerateSafeCastSet(verifier::MethodVerifier* method_verifier) {
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/*
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* Walks over the method code and adds any cast instructions in which
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* the type cast is implicit to a set, which is used in the code generation
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* to elide these casts.
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*/
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if (method_verifier->HasFailures()) {
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return;
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}
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const DexFile::CodeItem* code_item = method_verifier->CodeItem();
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const Instruction* inst = Instruction::At(code_item->insns_);
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const Instruction* end = Instruction::At(code_item->insns_ +
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code_item->insns_size_in_code_units_);
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for (; inst < end; inst = inst->Next()) {
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Instruction::Code code = inst->Opcode();
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if (code == Instruction::CHECK_CAST) {
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uint32_t dex_pc = inst->GetDexPc(code_item->insns_);
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if (!method_verifier->GetInstructionFlags(dex_pc).IsVisited()) {
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// Do not attempt to quicken this instruction, it's unreachable anyway.
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continue;
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}
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const verifier::RegisterLine* line = method_verifier->GetRegLine(dex_pc);
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const verifier::RegType& reg_type(line->GetRegisterType(method_verifier,
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inst->VRegA_21c()));
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const verifier::RegType& cast_type =
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method_verifier->ResolveCheckedClass(dex::TypeIndex(inst->VRegB_21c()));
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// Pass null for the method verifier to not record the VerifierDeps dependency
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// if the types are not assignable.
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if (cast_type.IsStrictlyAssignableFrom(reg_type, /* method_verifier */ nullptr)) {
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// The types are assignable, we record that dependency in the VerifierDeps so
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// that if this changes after OTA, we will re-verify again.
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// We check if reg_type has a class, as the verifier may have inferred it's
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// 'null'.
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if (reg_type.HasClass()) {
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DCHECK(cast_type.HasClass());
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verifier::VerifierDeps::MaybeRecordAssignability(method_verifier->GetDexFile(),
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cast_type.GetClass(),
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reg_type.GetClass(),
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/* strict */ true,
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/* assignable */ true);
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}
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if (safe_cast_set_ == nullptr) {
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safe_cast_set_.reset(new SafeCastSet());
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}
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// Verify ordering for push_back() to the sorted vector.
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DCHECK(safe_cast_set_->empty() || safe_cast_set_->back() < dex_pc);
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safe_cast_set_->push_back(dex_pc);
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}
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}
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}
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DCHECK(safe_cast_set_ == nullptr || !safe_cast_set_->empty());
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}
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} // namespace art
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