boost_unordered/test/unordered/unnecessary_copy_tests.cpp

// Copyright 2006-2009 Daniel James.
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)

// clang-format off
#include "../helpers/prefix.hpp"
#include <boost/unordered_set.hpp>
#include <boost/unordered_map.hpp>
#include "../helpers/postfix.hpp"
// clang-format on

#include "../helpers/test.hpp"

namespace unnecessary_copy_tests {
  struct count_copies
  {
  private:
    BOOST_COPYABLE_AND_MOVABLE(count_copies)
  public:
    static int copies;
    static int moves;
    static int id_count;

    count_copies() : tag_(0), id_(++id_count)
    {
      ++copies;
      trace_op("Default construct");
    }

    explicit count_copies(int tag) : tag_(tag), id_(++id_count)
    {
      ++copies;
      trace_op("Tag construct");
    }

    // This bizarre constructor is an attempt to confuse emplace.
    //
    // unordered_map<count_copies, count_copies> x:
    // x.emplace(count_copies(1), count_copies(2));
    // x.emplace(count_copies(1), count_copies(2), count_copies(3));
    //
    // The first emplace should use the single argument constructor twice.
    // The second emplace should use the single argument contructor for
    // the key, and this constructor for the value.
    count_copies(count_copies const&, count_copies const& x)
        : tag_(x.tag_), id_(++id_count)
    {
      ++copies;
      trace_op("Pair construct");
    }

    count_copies(count_copies const& x) : tag_(x.tag_), id_(++id_count)
    {
      ++copies;
      trace_op("Copy construct");
    }

    count_copies(BOOST_RV_REF(count_copies) x) : tag_(x.tag_), id_(++id_count)
    {
      x.tag_ = -1;
      ++moves;
      trace_op("Move construct");
    }

    count_copies& operator=(
      BOOST_COPY_ASSIGN_REF(count_copies) p) // Copy assignment
    {
      tag_ = p.tag_;
      ++copies;
      trace_op("Copy assign");
      return *this;
    }

    count_copies& operator=(BOOST_RV_REF(count_copies) p) // Move assignment
    {
      tag_ = p.tag_;
      ++moves;
      trace_op("Move assign");
      return *this;
    }

    ~count_copies() { trace_op("Destruct"); }

    void trace_op(char const* str)
    {
      BOOST_LIGHTWEIGHT_TEST_OSTREAM << str << ": " << tag_ << " (#" << id_
                                     << ")" << std::endl;
    }

    int tag_;
    int id_;
  };

  bool operator==(count_copies const& x, count_copies const& y)
  {
    return x.tag_ == y.tag_;
  }

  template <class T> T source() { return T(); }

  void reset()
  {
    count_copies::copies = 0;
    count_copies::moves = 0;

    BOOST_LIGHTWEIGHT_TEST_OSTREAM << "\nReset\n" << std::endl;
  }
}

#if defined(BOOST_NO_ARGUMENT_DEPENDENT_LOOKUP)
namespace boost
#else
namespace unnecessary_copy_tests
#endif
{
  std::size_t hash_value(unnecessary_copy_tests::count_copies const& x)
  {
    return static_cast<std::size_t>(x.tag_);
  }
}

// Boost.Move doesn't seem to work very well on this compiler.
// For example for:
//
//     T x;
//
// It will default construct T, and then move it in.
// For 'T const' it seems to copy.

#if defined(__IBMCPP__) && __IBMCPP__ <= 1210
#define EXTRA_CONSTRUCT_COST 1
#else
#define EXTRA_CONSTRUCT_COST 0
#endif

#define COPY_COUNT(n)                                                          \
  if (::unnecessary_copy_tests::count_copies::copies != n) {                   \
    BOOST_ERROR("Wrong number of copies.");                                    \
    BOOST_LIGHTWEIGHT_TEST_OSTREAM                                             \
      << "Number of copies: "                                                  \
      << ::unnecessary_copy_tests::count_copies::copies << " expecting: " << n \
      << std::endl;                                                            \
  }
#define MOVE_COUNT(n)                                                          \
  if (::unnecessary_copy_tests::count_copies::moves != n) {                    \
    BOOST_ERROR("Wrong number of moves.");                                     \
    BOOST_LIGHTWEIGHT_TEST_OSTREAM                                             \
      << "Number of moves: " << ::unnecessary_copy_tests::count_copies::moves  \
      << " expecting: " << n << std::endl;                                     \
  }
#define COPY_COUNT_RANGE(a, b)                                                 \
  if (::unnecessary_copy_tests::count_copies::copies < a ||                    \
      ::unnecessary_copy_tests::count_copies::copies > b) {                    \
    BOOST_ERROR("Wrong number of copies.");                                    \
    BOOST_LIGHTWEIGHT_TEST_OSTREAM                                             \
      << "Number of copies: "                                                  \
      << ::unnecessary_copy_tests::count_copies::copies << " expecting: ["     \
      << a << ", " << b << "]" << std::endl;                                   \
  }
#define MOVE_COUNT_RANGE(a, b)                                                 \
  if (::unnecessary_copy_tests::count_copies::moves < a ||                     \
      ::unnecessary_copy_tests::count_copies::moves > b) {                     \
    BOOST_ERROR("Wrong number of moves.");                                     \
    BOOST_LIGHTWEIGHT_TEST_OSTREAM                                             \
      << "Number of moves: " << ::unnecessary_copy_tests::count_copies::moves  \
      << " expecting: [" << a << ", " << b << "]" << std::endl;                \
  }
#define COPY_COUNT_EXTRA(a, b) COPY_COUNT_RANGE(a, a + b * EXTRA_CONSTRUCT_COST)
#define MOVE_COUNT_EXTRA(a, b) MOVE_COUNT_RANGE(a, a + b * EXTRA_CONSTRUCT_COST)

namespace unnecessary_copy_tests {
  int count_copies::copies;
  int count_copies::moves;
  int count_copies::id_count;

  template <class T> void unnecessary_copy_insert_test(T*)
  {
    T x;
    BOOST_DEDUCED_TYPENAME T::value_type a;
    reset();
    x.insert(a);
    COPY_COUNT(1);
    MOVE_COUNT(0);
  }

  template <class T> void unnecessary_copy_insert_rvalue_set_test(T*)
  {
    T x;
    BOOST_DEDUCED_TYPENAME T::value_type a;
    reset();
    x.insert(boost::move(a));
    COPY_COUNT(0);
    MOVE_COUNT(1);

    BOOST_DEDUCED_TYPENAME T::value_type a2;
    reset();
    x.insert(boost::move(a));
    COPY_COUNT(0);
    MOVE_COUNT((x.size() == 2 ? 1 : 0));
  }

  template <class T> void unnecessary_copy_insert_rvalue_map_test(T*)
  {
    // Doesn't currently try to emulate std::pair move construction,
    // so std::pair's require a copy. Could try emulating it in
    // construct_from_args.

    T x;
    BOOST_DEDUCED_TYPENAME T::value_type a;
    reset();
    x.insert(boost::move(a));
#if defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
    COPY_COUNT(1);
    MOVE_COUNT(0);
#else
    COPY_COUNT(0);
    MOVE_COUNT(1);
#endif

    BOOST_DEDUCED_TYPENAME T::value_type a2;
    reset();
    x.insert(boost::move(a));
#if defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
    COPY_COUNT((x.size() == 2 ? 1 : 0));
    MOVE_COUNT(0);
#else
    COPY_COUNT(0);
    MOVE_COUNT((x.size() == 2 ? 1 : 0));
#endif
  }

  boost::unordered_set<count_copies>* set;
  boost::unordered_multiset<count_copies>* multiset;
  boost::unordered_map<int, count_copies>* map;
  boost::unordered_multimap<int, count_copies>* multimap;

  UNORDERED_TEST(unnecessary_copy_insert_test, ((set)(multiset)(map)(multimap)))
  UNORDERED_TEST(unnecessary_copy_insert_rvalue_set_test, ((set)(multiset)))
  UNORDERED_TEST(unnecessary_copy_insert_rvalue_map_test, ((map)(multimap)))

  template <class T> void unnecessary_copy_emplace_test(T*)
  {
    reset();
    T x;
    BOOST_DEDUCED_TYPENAME T::value_type a;
    COPY_COUNT(1);
    x.emplace(a);
    COPY_COUNT(2);
  }

  template <class T> void unnecessary_copy_emplace_rvalue_test(T*)
  {
    reset();
    T x;
    x.emplace(source<BOOST_DEDUCED_TYPENAME T::value_type>());
#if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
    COPY_COUNT(1);
#else
    COPY_COUNT(2);
#endif
  }

  UNORDERED_TEST(
    unnecessary_copy_emplace_test, ((set)(multiset)(map)(multimap)))
  UNORDERED_TEST(
    unnecessary_copy_emplace_rvalue_test, ((set)(multiset)(map)(multimap)))

#if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
  template <class T> void unnecessary_copy_emplace_std_move_test(T*)
  {
    reset();
    T x;
    BOOST_DEDUCED_TYPENAME T::value_type a;
    COPY_COUNT(1);
    MOVE_COUNT(0);
    x.emplace(std::move(a));
    COPY_COUNT(1);
    MOVE_COUNT(1);
  }

  UNORDERED_TEST(
    unnecessary_copy_emplace_std_move_test, ((set)(multiset)(map)(multimap)))
#endif

  template <class T> void unnecessary_copy_emplace_boost_move_test(T*)
  {
    reset();
    T x;
    BOOST_DEDUCED_TYPENAME T::value_type a;
    COPY_COUNT(1);
    MOVE_COUNT_EXTRA(0, 1);
    x.emplace(boost::move(a));
#if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
    COPY_COUNT(1);
    MOVE_COUNT(1);
#else
    // Since std::pair isn't movable, move only works for sets.
    COPY_COUNT_RANGE(1, 2);
    MOVE_COUNT_RANGE(0, 1);
#endif
  }

  UNORDERED_TEST(
    unnecessary_copy_emplace_boost_move_test, ((set)(multiset)(map)(multimap)))

  template <class T> void unnecessary_copy_emplace_boost_move_set_test(T*)
  {
    reset();
    T x;
    BOOST_DEDUCED_TYPENAME T::value_type a;
    COPY_COUNT(1);
    MOVE_COUNT(0);
    x.emplace(boost::move(a));
    COPY_COUNT(1);
    MOVE_COUNT(1);
  }

  UNORDERED_TEST(
    unnecessary_copy_emplace_boost_move_set_test, ((set)(multiset)))

  template <class T> void unnecessary_copy_emplace_boost_move_map_test(T*)
  {
    reset();
    T x;
    COPY_COUNT(0);
    MOVE_COUNT(0);
    BOOST_DEDUCED_TYPENAME T::value_type a;
    COPY_COUNT(1);
    MOVE_COUNT_EXTRA(0, 1);
    x.emplace(boost::move(a));
#if defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
    COPY_COUNT(2);
    MOVE_COUNT_EXTRA(0, 1);
#else
    COPY_COUNT(1);
    MOVE_COUNT(1);
#endif
  }

  UNORDERED_TEST(
    unnecessary_copy_emplace_boost_move_map_test, ((map)(multimap)))

  UNORDERED_AUTO_TEST(unnecessary_copy_emplace_set_test)
  {
    // When calling 'source' the object is moved on some compilers, but not
    // others. So count that here to adjust later.

    reset();
    source<count_copies>();
    int source_cost = ::unnecessary_copy_tests::count_copies::moves;

    //

    reset();
    boost::unordered_set<count_copies> x;
    count_copies a;
    x.insert(a);
    COPY_COUNT(2);
    MOVE_COUNT(0);

//
// 0 arguments
//

#if !BOOST_UNORDERED_SUN_WORKAROUNDS1
    // The container will have to create a copy in order to compare with
    // the existing element.
    reset();
    x.emplace();

    // source_cost doesn't make much sense here, but it seems to fit.
    COPY_COUNT(1);
    MOVE_COUNT(source_cost);
#endif

    //
    // 1 argument
    //

    // Emplace should be able to tell that there already is an element
    // without creating a new one.
    reset();
    x.emplace(a);
    COPY_COUNT(0);
    MOVE_COUNT(0);

    // A new object is created by source, but it shouldn't be moved or
    // copied.
    reset();
    x.emplace(source<count_copies>());
    COPY_COUNT(1);
    MOVE_COUNT(source_cost);

    // No move should take place.
    reset();
    x.emplace(boost::move(a));
    COPY_COUNT(0);
    MOVE_COUNT(0);

    // Use a new value for cases where a did get moved...
    count_copies b;

    // The container will have to create a copy in order to compare with
    // the existing element.
    reset();
    x.emplace(b.tag_);
    COPY_COUNT(1);
    MOVE_COUNT(0);

    //
    // 2 arguments
    //

    // The container will have to create b copy in order to compare with
    // the existing element.
    //
    // Note to self: If copy_count == 0 it's an error not an optimization.
    // TODO: Devise a better test.

    reset();

    x.emplace(b, b);
    COPY_COUNT(1);
    MOVE_COUNT(0);
  }

  UNORDERED_AUTO_TEST(unnecessary_copy_emplace_map_test)
  {
    // When calling 'source' the object is moved on some compilers, but not
    // others. So count that here to adjust later.

    reset();
    source<count_copies>();
    int source_cost = ::unnecessary_copy_tests::count_copies::moves;

    reset();
    source<std::pair<count_copies, count_copies> >();
    int source_pair_cost = ::unnecessary_copy_tests::count_copies::moves;

    //

    reset();
    boost::unordered_map<count_copies, count_copies> x;
    // TODO: Run tests for pairs without const etc.
    std::pair<count_copies const, count_copies> a;
    x.emplace(a);
    COPY_COUNT_EXTRA(4, 1);
    MOVE_COUNT_EXTRA(0, 1);

//
// 0 arguments
//

#if !BOOST_UNORDERED_SUN_WORKAROUNDS1
    // COPY_COUNT(1) would be okay here.
    reset();
    x.emplace();
#if BOOST_WORKAROUND(BOOST_MSVC, == 1700)
    // This is a little odd, Visual C++ 11 seems to move the pair, which
    // results in one copy (for the const key) and one move (for the
    // non-const mapped value). Since 'emplace(boost::move(a))' (see below)
    // has the normal result, it must be some odd consequence of how
    // Visual C++ 11 handles calling move for default arguments.
    COPY_COUNT(3);
    MOVE_COUNT(1);
#else
    COPY_COUNT_EXTRA(2, 1);
    MOVE_COUNT_EXTRA(0, 1);
#endif
#endif

    reset();
    x.emplace(boost::unordered::piecewise_construct, boost::make_tuple(),
      boost::make_tuple());
    COPY_COUNT(2);
    MOVE_COUNT(0);

    //
    // 1 argument
    //

    reset();
    x.emplace(a);
    COPY_COUNT(0);
    MOVE_COUNT(0);

    // A new object is created by source, but it shouldn't be moved or
    // copied.
    reset();
    x.emplace(source<std::pair<count_copies, count_copies> >());
    COPY_COUNT(2);
    MOVE_COUNT(source_pair_cost);

#if !(defined(__GNUC__) && __cplusplus < 199900L) &&                           \
  !(defined(_MSC_VER) && _MSC_VER < 1600)
    count_copies part;
    reset();
    std::pair<count_copies const&, count_copies const&> a_ref(part, part);
    x.emplace(a_ref);
    COPY_COUNT(2);
    MOVE_COUNT(0);

#endif

    // No move should take place.
    // (since a is already in the container)
    reset();
    x.emplace(boost::move(a));
    COPY_COUNT(0);
    MOVE_COUNT(0);

    //
    // 2 arguments
    //

    std::pair<count_copies const, count_copies> b;

    reset();
    x.emplace(b.first, b.second);
    COPY_COUNT(0);
    MOVE_COUNT(0);

    reset();
    x.emplace(source<count_copies>(), source<count_copies>());
    COPY_COUNT(2);
    MOVE_COUNT(source_cost * 2);

    // source<count_copies> creates a single copy.
    reset();
    x.emplace(b.first, source<count_copies>());
    COPY_COUNT(1);
    MOVE_COUNT(source_cost);

    reset();
    x.emplace(count_copies(b.first.tag_), count_copies(b.second.tag_));
    COPY_COUNT(2);
    MOVE_COUNT(0);

    reset();
    x.emplace(boost::unordered::piecewise_construct,
      boost::make_tuple(boost::ref(b.first)),
      boost::make_tuple(boost::ref(b.second)));
    COPY_COUNT(0);
    MOVE_COUNT(0);

#if BOOST_UNORDERED_TUPLE_ARGS

    reset();
    x.emplace(boost::unordered::piecewise_construct,
      std::make_tuple(std::ref(b.first)), std::make_tuple(std::ref(b.second)));
    COPY_COUNT(0);
    MOVE_COUNT(0);

    std::pair<count_copies const, count_copies> move_source_trial;
    reset();
    std::make_tuple(std::move(move_source_trial.first));
    std::make_tuple(std::move(move_source_trial.second));
    int tuple_move_cost = ::unnecessary_copy_tests::count_copies::moves;
    int tuple_copy_cost = ::unnecessary_copy_tests::count_copies::copies;

    std::pair<count_copies const, count_copies> move_source;
    reset();
    x.emplace(boost::unordered::piecewise_construct,
      std::make_tuple(std::move(move_source.first)),
      std::make_tuple(std::move(move_source.second)));
    COPY_COUNT(tuple_copy_cost);
    MOVE_COUNT(tuple_move_cost);

#if !defined(BOOST_NO_CXX11_HDR_TUPLE) &&                                      \
  !(defined(__GNUC__) && __GNUC__ == 4 && __GNUC_MINOR__ < 6) &&               \
  !(defined(BOOST_MSVC) && BOOST_MSVC < 1700)
    reset();
    x.emplace(boost::unordered::piecewise_construct,
      std::forward_as_tuple(b.first), std::forward_as_tuple(b.second));
    COPY_COUNT(0);
    MOVE_COUNT(0);
#endif

#endif
  }
}

RUN_TESTS()