SPIRV-Tools/source/id_descriptor.h

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// Copyright (c) 2017 Google Inc.
//
// 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 LIBSPIRV_ID_DESCRIPTOR_H_
#define LIBSPIRV_ID_DESCRIPTOR_H_
#include <unordered_map>
#include <vector>
#include "spirv-tools/libspirv.hpp"
namespace libspirv {
using CustomHashFunc = std::function<uint32_t(const std::vector<uint32_t>&)>;
// Computes and stores id descriptors.
//
// Descriptors are computed as hash of all words in the instruction where ids
// were substituted with previously computed descriptors.
class IdDescriptorCollection {
public:
explicit IdDescriptorCollection(
CustomHashFunc custom_hash_func = CustomHashFunc())
: custom_hash_func_(custom_hash_func) {
words_.reserve(16);
}
// Computes descriptor for the result id of the given instruction and
// registers it in id_to_descriptor_. Returns the computed descriptor.
// This function needs to be sequentially called for every instruction in the
// module.
uint32_t ProcessInstruction(const spv_parsed_instruction_t& inst);
// Returns a previously computed descriptor id.
uint32_t GetDescriptor(uint32_t id) const {
const auto it = id_to_descriptor_.find(id);
if (it == id_to_descriptor_.end()) return 0;
return it->second;
}
private:
std::unordered_map<uint32_t, uint32_t> id_to_descriptor_;
std::function<uint32_t(const std::vector<uint32_t>&)> custom_hash_func_;
// Scratch buffer used for hashing. Class member to optimize on allocation.
std::vector<uint32_t> words_;
};
} // namespace libspirv
#endif // LIBSPIRV_ID_DESCRIPTOR_H_