Method Apply

source/fuzz/fuzzer_pass_replace_irrelevant_ids.cpp:35–179

                 transformations, ignore_inapplicable_transformations) {}

void FuzzerPassReplaceIrrelevantIds::Apply() {
  // Keep track of the irrelevant ids. This includes all the ids that are
  // irrelevant according to the fact manager and that are still present in the
  // module (some of them may have been removed by previously-run
  // transformations).
  std::vector<uint32_t> irrelevant_ids;

  // Keep a map from the type ids of irrelevant ids to all the ids with that
  // type.
  std::unordered_map<uint32_t, std::vector<uint32_t>> types_to_ids;

  // Find all the irrelevant ids that still exist in the module and all the
  // types for which irrelevant ids exist.
  for (auto id :
       GetTransformationContext()->GetFactManager()->GetIrrelevantIds()) {
    // Check that the id still exists in the module.
    auto declaration = GetIRContext()->get_def_use_mgr()->GetDef(id);
    if (!declaration) {
      continue;
    }

    irrelevant_ids.push_back(id);

    // If the type of this id has not been seen before, add a mapping from this
    // type id to an empty list in |types_to_ids|. The list will be filled later
    // on.
    if (types_to_ids.count(declaration->type_id()) == 0) {
      types_to_ids.insert({declaration->type_id(), {}});
    }
  }

  // If no irrelevant ids were found, return.
  if (irrelevant_ids.empty()) {
    return;
  }

  // For every type for which we have at least one irrelevant id, record all ids
  // in the module which have that type. Skip ids of OpFunction instructions as
  // we cannot use these as replacements.
  for (const auto& pair : GetIRContext()->get_def_use_mgr()->id_to_defs()) {
    uint32_t type_id = pair.second->type_id();
    if (pair.second->opcode() != spv::Op::OpFunction && type_id &&
        types_to_ids.count(type_id)) {
      types_to_ids[type_id].push_back(pair.first);
    }
  }

  // Keep a list of all the transformations to perform. We avoid applying the
  // transformations while traversing the uses since applying the transformation
  // invalidates all analyses, and we want to avoid invalidating and recomputing
  // them every time.
  std::vector<TransformationReplaceIrrelevantId> transformations_to_apply;

  // Loop through all the uses of irrelevant ids, check that the id can be
  // replaced and randomly decide whether to apply the transformation.
  for (auto irrelevant_id : irrelevant_ids) {
    uint32_t type_id =
        GetIRContext()->get_def_use_mgr()->GetDef(irrelevant_id)->type_id();