text: // Copyright (c) 2020 Google LLC
  //
  // 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 SOURCE_FUZZ_TRANSFORMATION_REPLACE_IRRELEVANT_ID_H_
  #define SOURCE_FUZZ_TRANSFORMATION_REPLACE_IRRELEVANT_ID_H_
  
  #include "source/fuzz/transformation.h"
  
  namespace spvtools {
  namespace fuzz {
  
  class TransformationReplaceIrrelevantId : public Transformation {
   public:
    explicit TransformationReplaceIrrelevantId(
        const protobufs::TransformationReplaceIrrelevantId& message);
  
    TransformationReplaceIrrelevantId(
        const protobufs::IdUseDescriptor& id_use_descriptor,
        uint32_t replacement_id);
  
    // - The id of interest in |message_.id_use_descriptor| is irrelevant
    //   according to the fact manager.
    // - The types of the original id and of the replacement ids are the same.
    // - The replacement must not be the result id of an OpFunction instruction.
    // - |message_.replacement_id| is available to use at the enclosing
    //   instruction of |message_.id_use_descriptor|.
    // - The original id is in principle replaceable with any other id of the same
    //   type. See fuzzerutil::IdUseCanBeReplaced for details.
    bool IsApplicable(
        opt::IRContext* ir_context,
        const TransformationContext& transformation_context) const override;
  
    // Replaces the use of an irrelevant id identified by
    // |message_.id_use_descriptor| with the id |message_.replacement_id|, which
    // has the same type as the id of interest.
    void Apply(opt::IRContext* ir_context,
               TransformationContext* transformation_context) const override;
  
    std::unordered_set<uint32_t> GetFreshIds() const override;
  
    protobufs::Transformation ToMessage() const override;
  
    // Returns true if and only if |use_instruction| is OpVariable and
    // |replacement_for_use| is not a constant instruction - i.e., if it would be
    // illegal to replace the variable's initializer with the given instruction.
    static bool AttemptsToReplaceVariableInitializerWithNonConstant(
        const opt::Instruction& use_instruction,
        const opt::Instruction& replacement_for_use);
  
   private:
    protobufs::TransformationReplaceIrrelevantId message_;
  };
  
  }  // namespace fuzz
  }  // namespace spvtools
  
  #endif  // SOURCE_FUZZ_TRANSFORMATION_REPLACE_IRRELEVANT_ID_H_
  