blob: e46dc597fae9d9e055adeaac307afb82f1348d0e [file] [log] [blame]
/*
* 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 "base/logging.h"
#include "dex_file.h"
#include "dex_instruction-inl.h"
#include "runtime.h"
#include "verifier/method_verifier-inl.h"
#include "verifier/reg_type-inl.h"
#include "verifier/register_line-inl.h"
#include "verifier/verifier_deps.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) {
DCHECK(Runtime::Current()->IsAotCompiler());
std::unique_ptr<VerifiedMethod> verified_method(
new VerifiedMethod(method_verifier->GetEncounteredFailureTypes(),
method_verifier->HasInstructionThatWillThrow()));
if (method_verifier->HasCheckCasts()) {
verified_method->GenerateSafeCastSet(method_verifier);
}
return verified_method.release();
}
bool VerifiedMethod::IsSafeCast(uint32_t pc) const {
if (safe_cast_set_ == nullptr) {
return false;
}
return std::binary_search(safe_cast_set_->begin(), safe_cast_set_->end(), pc);
}
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) {
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);
const verifier::RegType& reg_type(line->GetRegisterType(method_verifier,
inst->VRegA_21c()));
const verifier::RegType& cast_type =
method_verifier->ResolveCheckedClass(dex::TypeIndex(inst->VRegB_21c()));
// Pass null for the method verifier to not record the VerifierDeps dependency
// if the types are not assignable.
if (cast_type.IsStrictlyAssignableFrom(reg_type, /* method_verifier */ nullptr)) {
// The types are assignable, we record that dependency in the VerifierDeps so
// that if this changes after OTA, we will re-verify again.
// We check if reg_type has a class, as the verifier may have inferred it's
// 'null'.
if (reg_type.HasClass()) {
DCHECK(cast_type.HasClass());
verifier::VerifierDeps::MaybeRecordAssignability(method_verifier->GetDexFile(),
cast_type.GetClass(),
reg_type.GetClass(),
/* strict */ true,
/* assignable */ true);
}
if (safe_cast_set_ == nullptr) {
safe_cast_set_.reset(new SafeCastSet());
}
// 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);
}
}
}
DCHECK(safe_cast_set_ == nullptr || !safe_cast_set_->empty());
}
} // namespace art