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/*
* Copyright (C) 2016 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.
*/
#ifndef ART_RUNTIME_IMTABLE_INL_H_
#define ART_RUNTIME_IMTABLE_INL_H_
#include "imtable.h"
#include "art_method-inl.h"
#include "dex/dex_file.h"
#include "dex/utf.h"
namespace art {
static constexpr bool kImTableHashUseName = true;
static constexpr bool kImTableHashUseCoefficients = true;
// Magic configuration that minimizes some common runtime calls.
static constexpr uint32_t kImTableHashCoefficientClass = 427;
static constexpr uint32_t kImTableHashCoefficientName = 16;
static constexpr uint32_t kImTableHashCoefficientSignature = 14;
inline void ImTable::GetImtHashComponents(ArtMethod* method,
uint32_t* class_hash,
uint32_t* name_hash,
uint32_t* signature_hash) {
if (kImTableHashUseName) {
if (method->IsProxyMethod()) {
*class_hash = 0;
*name_hash = 0;
*signature_hash = 0;
return;
}
const DexFile* dex_file = method->GetDexFile();
const dex::MethodId& method_id = dex_file->GetMethodId(method->GetDexMethodIndex());
// Class descriptor for the class component.
*class_hash = ComputeModifiedUtf8Hash(dex_file->GetMethodDeclaringClassDescriptor(method_id));
// Method name for the method component.
*name_hash = ComputeModifiedUtf8Hash(dex_file->GetMethodName(method_id));
const dex::ProtoId& proto_id = dex_file->GetMethodPrototype(method_id);
// Read the proto for the signature component.
uint32_t tmp = ComputeModifiedUtf8Hash(
dex_file->GetTypeDescriptor(dex_file->GetTypeId(proto_id.return_type_idx_)));
// Mix in the argument types.
// Note: we could consider just using the shorty. This would be faster, at the price of
// potential collisions.
const dex::TypeList* param_types = dex_file->GetProtoParameters(proto_id);
if (param_types != nullptr) {
for (size_t i = 0; i != param_types->Size(); ++i) {
const dex::TypeItem& type = param_types->GetTypeItem(i);
tmp = 31 * tmp + ComputeModifiedUtf8Hash(
dex_file->GetTypeDescriptor(dex_file->GetTypeId(type.type_idx_)));
}
}
*signature_hash = tmp;
return;
} else {
*class_hash = method->GetDexMethodIndex();
*name_hash = 0;
*signature_hash = 0;
return;
}
}
inline uint32_t ImTable::GetImtIndex(ArtMethod* method) {
uint32_t class_hash, name_hash, signature_hash;
GetImtHashComponents(method, &class_hash, &name_hash, &signature_hash);
uint32_t mixed_hash;
if (!kImTableHashUseCoefficients) {
mixed_hash = class_hash + name_hash + signature_hash;
} else {
mixed_hash = kImTableHashCoefficientClass * class_hash +
kImTableHashCoefficientName * name_hash +
kImTableHashCoefficientSignature * signature_hash;
}
return mixed_hash % ImTable::kSize;
}
} // namespace art
#endif // ART_RUNTIME_IMTABLE_INL_H_
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