structural_hash.h

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/*
 * 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.
 */
#ifndef TVM_NODE_STRUCTURAL_HASH_H_
#define TVM_NODE_STRUCTURAL_HASH_H_
 
#include <tvm/node/functor.h>
#include <tvm/runtime/data_type.h>
#include <tvm/runtime/tensor.h>
 
#include <cmath>
#include <functional>
#include <limits>
#include <string>
 
namespace tvm {
 
class BaseValueHash {
 protected:
  template <typename T, typename U>
  uint64_t Reinterpret(T value) const {
    union Union {
      T a;
      U b;
    } u;
    static_assert(sizeof(Union) == sizeof(T), "sizeof(Union) != sizeof(T)");
    static_assert(sizeof(Union) == sizeof(U), "sizeof(Union) != sizeof(U)");
    u.b = 0;
    u.a = value;
    return u.b;
  }
 
 public:
  uint64_t operator()(const float& key) const { return Reinterpret<float, uint32_t>(key); }
  uint64_t operator()(const double& key) const {
    if (std::isnan(key)) {
      // The IEEE format defines more than one bit-pattern that
      // represents NaN.  For the purpose of comparing IR
      // representations, all NaN values are considered equivalent.
      return Reinterpret<double, uint64_t>(std::numeric_limits<double>::quiet_NaN());
    } else {
      return Reinterpret<double, uint64_t>(key);
    }
  }
  uint64_t operator()(const int64_t& key) const { return Reinterpret<int64_t, uint64_t>(key); }
  uint64_t operator()(const uint64_t& key) const { return key; }
  uint64_t operator()(const int& key) const { return Reinterpret<int, uint32_t>(key); }
  uint64_t operator()(const bool& key) const { return key; }
  uint64_t operator()(const runtime::DataType& key) const {
    return Reinterpret<DLDataType, uint32_t>(key);
  }
  template <typename ENum, typename = typename std::enable_if<std::is_enum<ENum>::value>::type>
  uint64_t operator()(const ENum& key) const {
    return Reinterpret<int64_t, uint64_t>(static_cast<int64_t>(key));
  }
  uint64_t operator()(const std::string& key) const {
    return tvm::ffi::details::StableHashBytes(key.data(), key.length());
  }
  uint64_t operator()(const ffi::Optional<int64_t>& key) const {
    if (key.has_value()) {
      return Reinterpret<int64_t, uint64_t>(*key);
    } else {
      return 0;
    }
  }
  uint64_t operator()(const ffi::Optional<double>& key) const {
    if (key.has_value()) {
      return Reinterpret<double, uint64_t>(*key);
    } else {
      return 0;
    }
  }
  TVM_FFI_INLINE uint64_t HashPODValueInAny(const ffi::Any& key) const {
    return ffi::details::AnyUnsafe::TVMFFIAnyPtrFromAny(key)->v_uint64;
  }
};
 
class StructuralHash : public BaseValueHash {
 public:
  // inherit operator()
  using BaseValueHash::operator();
  TVM_DLL uint64_t operator()(const ffi::Any& key) const;
};
 
}  // namespace tvm
#endif  // TVM_NODE_STRUCTURAL_HASH_H_