tqchen commented on a change in pull request #4346: [Runtime] Make ADTObject POD container type URL: https://github.com/apache/incubator-tvm/pull/4346#discussion_r350514759
########## File path: include/tvm/runtime/container.h ########## @@ -0,0 +1,282 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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. + */ + +/*! + * \file tvm/runtime/container.h + * \brief Common POD(plain old data) container types. + */ +#ifndef TVM_RUNTIME_CONTAINER_H_ +#define TVM_RUNTIME_CONTAINER_H_ +#include <dmlc/logging.h> +#include <tvm/runtime/memory.h> +#include <tvm/runtime/object.h> + +#include <initializer_list> +#include <type_traits> +#include <utility> +#include <vector> + +namespace tvm { +namespace runtime { + +/*! + * \brief Base template for classes with array like memory layout. + * + * It provides general methods to access the memory. The memory + * layout is ArrayType + [ElemType]. The alignment of ArrayType + * and ElemType is handled by the memory allocator. + * + * \tparam ArrayType The array header type, contains object specific metadata. + * \tparam ElemType The type of objects stored in the array right after + * ArrayType. + * + * \code + * // Example usage of the template to define a simple array wrapper + * class ArrayObj : public InplaceArrayBase<ArrayObj, Elem> { + * public: + * // Wrap EmplaceInit to initialize the elements + * template <typename Iterator> + * void Init(Iterator begin, Iterator end) { + * size_t num_elems = std::distance(begin, end); + * auto it = begin; + * for (size_t i = 0; i < num_elems; ++i) { + * InplaceArrayBase::EmplaceInit(i, *it++); + * } + * } + * } + * + * void test_function() { + * vector<Elem> fields; + * auto ptr = make_inplace_array_object<ArrayObj, Elem>(fields.size()); + * ptr->Init(fields.begin(), fields.end()); + * + * // Access the 0th element in the array. + * assert(ptr->operator[](0) == fields[0]); + * } + * + * \endcode + */ +template <typename ArrayType, typename ElemType> +class InplaceArrayBase { + public: + /*! + * \brief Access element at index + * \param idx The index of the element. + * \return Const reference to ElemType at the index. + */ + const ElemType& operator[](size_t idx) const { + size_t size = Self()->size(); + CHECK_LT(idx, size) << "Index " << idx << " out of bounds " << size << "\n"; + return *(reinterpret_cast<ElemType*>(AddressOf(idx))); + } + + /*! + * \brief Access element at index + * \param idx The index of the element. + * \return Reference to ElemType at the index. + */ + ElemType& operator[](size_t idx) { + size_t size = Self()->size(); + CHECK_LT(idx, size) << "Index " << idx << " out of bounds " << size << "\n"; + return *(reinterpret_cast<ElemType*>(AddressOf(idx))); + } + + /*! + * \brief Destroy the Inplace Array Base object + */ + ~InplaceArrayBase() { + if (!(std::is_standard_layout<ElemType>::value && + std::is_trivial<ElemType>::value)) { + size_t size = Self()->size(); + for (size_t i = 0; i < size; ++i) { + ElemType* fp = reinterpret_cast<ElemType*>(AddressOf(i)); + fp->ElemType::~ElemType(); + } + } + } + + protected: + /*! + * \brief Construct a value in place with the arguments. + * + * \tparam Args Type parameters of the arguments. + * \param idx Index of the element. + * \param args Arguments to construct the new value. + */ + template <typename... Args> + void EmplaceInit(size_t idx, Args&&... args) { + CHECK_LT(idx, Self()->capacity()) << "InplaceArray out of capacity\n"; + void* field_ptr = AddressOf(idx); + new (field_ptr) ElemType(std::forward<Args>(args)...); + } + + private: + /*! + * \brief Return the self object for the array. + * + * \return Pointer to ArrayType. + */ + inline ArrayType* Self() const { + return static_cast<ArrayType*>(const_cast<InplaceArrayBase*>(this)); + } + + /*! + * \brief Return the raw pointer to the element at idx. + * + * \param idx The index of the element. + * \return Raw pointer to the element. + */ + void* AddressOf(size_t idx) const { + static_assert(alignof(ArrayType) % alignof(ElemType) == 0 && + sizeof(ArrayType) % alignof(ElemType) == 0, + "The size and alignment of ArrayType should respect " + "ElemType's alignment."); + + size_t kDataStart = sizeof(ArrayType); + ArrayType* self = Self(); + char* data_start = reinterpret_cast<char*>(self) + kDataStart; + return data_start + idx * sizeof(ElemType); + } +}; + +/*! \brief An object representing a structure or enumeration. */ +class ADTObj : public Object, public InplaceArrayBase<ADTObj, ObjectRef> { + public: + /*! \brief The tag representing the constructor used. */ + uint32_t tag_; + /*! \brief Number of fields in the ADT object. */ + uint32_t size_; Review comment: Let us remove underscore as @icemelon9 suggested. We can expose a GetSize private function(make the base class a friend class) ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services
