Merge pull request #176 from boostorg/feature/foa_fast_copy_fix

feature/foa fast copy fix

include/boost/unordered/detail/foa.hpp

@@ -31,6 +31,7 @@
 #include <cstring>
 #include <iterator>
 #include <limits>
+#include <memory>
 #include <tuple>
 #include <type_traits>
 #include <utility>
@@ -1025,6 +1026,47 @@ inline void prefetch(const void* p)
 
 struct try_emplace_args_t{};
 
+template<typename Allocator>
+struct is_std_allocator:std::false_type{};
+
+template<typename T>
+struct is_std_allocator<std::allocator<T>>:std::true_type{};
+
+/* std::allocator::construct marked as deprecated */
+#if defined(_LIBCPP_SUPPRESS_DEPRECATED_PUSH)
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+#elif defined(_STL_DISABLE_DEPRECATED_WARNING)
+_STL_DISABLE_DEPRECATED_WARNING
+#elif defined(_MSC_VER)
+#pragma warning(push)
+#pragma warning(disable:4996)
+#endif
+
+template<typename Allocator,typename Ptr,typename... Args>
+struct alloc_has_construct
+{
+private:
+  template<typename Allocator2>
+  static decltype(
+    std::declval<Allocator2&>().construct(
+      std::declval<Ptr>(),std::declval<Args&&>()...),
+    std::true_type{}
+  ) check(int);
+
+  template<typename> static std::false_type check(...);
+
+public:
+  static constexpr bool value=decltype(check<Allocator>(0))::value;
+};
+
+#if defined(_LIBCPP_SUPPRESS_DEPRECATED_POP)
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#elif defined(_STL_RESTORE_DEPRECATED_WARNING)
+_STL_RESTORE_DEPRECATED_WARNING
+#elif defined(_MSC_VER)
+#pragma warning(pop)
+#endif
+
 #if defined(BOOST_GCC)
 /* GCC's -Wshadow triggers at scenarios like this: 
  *
@@ -1590,6 +1632,9 @@ private:
 #else
         std::is_trivially_copy_constructible<value_type>::value
 #endif
+        &&(
+          is_std_allocator<Allocator>::value||
+          !alloc_has_construct<Allocator,value_type*,const value_type&>::value)
       >{}
     );
   }

test/objects/test.hpp

@@ -230,18 +230,18 @@ namespace test {
 
     std::size_t operator()(int x) const
     {
-      int result;
+      unsigned result;
       switch (type_) {
       case 1:
-        result = x;
+        result = static_cast<unsigned>(x);
         break;
       case 2:
-        result = x * 7;
+        result = static_cast<unsigned>(x) * 7;
         break;
       default:
-        result = x * 256;
+        result = static_cast<unsigned>(x) * 256;
       }
-      return static_cast<std::size_t>(result);
+      return result;
     }
 
     friend bool operator==(hash const& x1, hash const& x2)

test/unordered/copy_tests.cpp

@@ -225,11 +225,227 @@ namespace copy_tests {
     }
   }
 
+  template <class T>
+  void copy_construct_tests_std_allocator1(
+    T*, test::random_generator const& generator)
+  {
+    typename T::hasher hf;
+    typename T::key_equal eq;
+    typename T::allocator_type al;
+
+    {
+      test::check_instances check_;
+
+      T x;
+      T y(x);
+      BOOST_TEST(y.empty());
+      BOOST_TEST(test::equivalent(y.hash_function(), hf));
+      BOOST_TEST(test::equivalent(y.key_eq(), eq));
+      BOOST_TEST(test::equivalent(y.get_allocator(), al));
+      BOOST_TEST(x.max_load_factor() == y.max_load_factor());
+      BOOST_TEST(test::detail::tracker.count_allocations == 0);
+      test::check_equivalent_keys(y);
+    }
+
+    {
+      test::check_instances check_;
+
+      T x(0);
+      T y(x);
+      BOOST_TEST(y.empty());
+      BOOST_TEST(test::equivalent(y.hash_function(), hf));
+      BOOST_TEST(test::equivalent(y.key_eq(), eq));
+      BOOST_TEST(test::equivalent(y.get_allocator(), al));
+      BOOST_TEST(x.max_load_factor() == y.max_load_factor());
+      BOOST_TEST(test::detail::tracker.count_allocations == 0);
+      test::check_equivalent_keys(y);
+    }
+
+    {
+      test::check_instances check_;
+
+      test::random_values<T> v(1000, generator);
+
+      T x(v.begin(), v.end());
+      T y(x);
+      test::unordered_equivalence_tester<T> equivalent(x);
+      BOOST_TEST(equivalent(y));
+      test::check_equivalent_keys(y);
+    }
+
+    {
+      test::check_instances check_;
+
+      // In this test I drop the original containers max load factor, so it
+      // is much lower than the load factor. The hash table is not allowed
+      // to rehash, but the destination container should probably allocate
+      // enough buckets to decrease the load factor appropriately.
+      test::random_values<T> v(1000, generator);
+      T x(v.begin(), v.end());
+      x.max_load_factor(x.load_factor() / 4);
+      T y(x);
+      test::unordered_equivalence_tester<T> equivalent(x);
+      BOOST_TEST(equivalent(y));
+      // This isn't guaranteed:
+      BOOST_TEST(y.load_factor() < y.max_load_factor());
+      test::check_equivalent_keys(y);
+    }
+  }
+
+  template <class T>
+  void copy_construct_tests_std_allocator2(
+    T*, test::random_generator const& generator)
+  {
+    typename T::hasher hf(1);
+    typename T::key_equal eq(1);
+    typename T::allocator_type al;
+
+    {
+      test::check_instances check_;
+
+      T x(0, hf, eq, al);
+      T y(x);
+      BOOST_TEST(y.empty());
+      BOOST_TEST(test::equivalent(y.hash_function(), hf));
+      BOOST_TEST(test::equivalent(y.key_eq(), eq));
+      BOOST_TEST(test::equivalent(y.get_allocator(), al));
+      BOOST_TEST(x.max_load_factor() == y.max_load_factor());
+      BOOST_TEST(test::detail::tracker.count_allocations == 0);
+      test::check_equivalent_keys(y);
+    }
+
+    {
+      test::check_instances check_;
+
+      T x(10000, hf, eq, al);
+      T y(x);
+      BOOST_TEST(y.empty());
+      BOOST_TEST(test::equivalent(y.hash_function(), hf));
+      BOOST_TEST(test::equivalent(y.key_eq(), eq));
+      BOOST_TEST(test::equivalent(y.get_allocator(), al));
+      BOOST_TEST(x.max_load_factor() == y.max_load_factor());
+      test::check_equivalent_keys(y);
+    }
+
+    {
+      test::check_instances check_;
+
+      T x(0, hf, eq, al);
+      T y(x, al);
+      BOOST_TEST(y.empty());
+      BOOST_TEST(test::equivalent(y.hash_function(), hf));
+      BOOST_TEST(test::equivalent(y.key_eq(), eq));
+      BOOST_TEST(test::equivalent(y.get_allocator(), al));
+      BOOST_TEST(x.max_load_factor() == y.max_load_factor());
+      BOOST_TEST(test::selected_count(y.get_allocator()) == 0);
+      BOOST_TEST(test::detail::tracker.count_allocations == 0);
+      test::check_equivalent_keys(y);
+    }
+
+    {
+      test::check_instances check_;
+
+      T x(1000, hf, eq, al);
+      T y(x, al);
+      BOOST_TEST(y.empty());
+      BOOST_TEST(test::equivalent(y.hash_function(), hf));
+      BOOST_TEST(test::equivalent(y.key_eq(), eq));
+      BOOST_TEST(test::equivalent(y.get_allocator(), al));
+      BOOST_TEST(x.max_load_factor() == y.max_load_factor());
+      BOOST_TEST(test::selected_count(y.get_allocator()) == 0);
+      test::check_equivalent_keys(y);
+    }
+
+    {
+      test::check_instances check_;
+
+      test::random_values<T> v;
+
+      T x(v.begin(), v.end(), 0, hf, eq, al);
+      T y(x);
+      test::unordered_equivalence_tester<T> equivalent(x);
+      BOOST_TEST(equivalent(y));
+      test::check_equivalent_keys(y);
+      BOOST_TEST(test::equivalent(y.get_allocator(), al));
+      BOOST_TEST(test::detail::tracker.count_allocations == 0);
+    }
+
+    {
+      test::check_instances check_;
+
+      test::random_values<T> v(1000, generator);
+
+      T x(v.begin(), v.end(), 0, hf, eq, al);
+      T y(x);
+      test::unordered_equivalence_tester<T> equivalent(x);
+      BOOST_TEST(equivalent(y));
+      test::check_equivalent_keys(y);
+      BOOST_TEST(test::equivalent(y.get_allocator(), al));
+    }
+
+    {
+      test::check_instances check_;
+
+      test::random_values<T> v;
+
+      T x(v.begin(), v.end(), 0, hf, eq, al);
+      T y(x, al);
+      test::unordered_equivalence_tester<T> equivalent(x);
+      BOOST_TEST(equivalent(y));
+      test::check_equivalent_keys(y);
+      BOOST_TEST(test::selected_count(y.get_allocator()) == 0);
+      BOOST_TEST(test::equivalent(y.get_allocator(), al));
+      BOOST_TEST(test::detail::tracker.count_allocations == 0);
+    }
+
+    {
+      test::check_instances check_;
+
+      test::random_values<T> v(500, generator);
+
+      T x(v.begin(), v.end(), 0, hf, eq, al);
+      T y(x, al);
+      test::unordered_equivalence_tester<T> equivalent(x);
+      BOOST_TEST(equivalent(y));
+      test::check_equivalent_keys(y);
+      BOOST_TEST(test::selected_count(y.get_allocator()) == 0);
+      BOOST_TEST(test::equivalent(y.get_allocator(), al));
+    }
+  }
+
   using test::default_generator;
   using test::generate_collisions;
   using test::limited_range;
 
 #ifdef BOOST_UNORDERED_FOA_TESTS
+  template <class T> struct allocator
+  {
+    using value_type = T;
+
+    allocator() = default;
+    allocator(allocator const&) = default;
+    allocator(allocator&&) = default;
+
+    template <class U> allocator(allocator<U> const&) {}
+
+    T* allocate(std::size_t n)
+    {
+      return static_cast<T*>(::operator new(sizeof(value_type) * n));
+    }
+
+    void deallocate(T* p, std::size_t) { ::operator delete(p); }
+
+    friend inline bool operator==(allocator const&, allocator const&)
+    {
+      return true;
+    }
+
+    friend inline bool operator!=(allocator const&, allocator const&)
+    {
+      return false;
+    }
+  };
+
   boost::unordered_flat_set<test::object, test::hash, test::equal_to,
     test::allocator1<test::object> >* test_set;
   boost::unordered_flat_map<test::object, test::object, test::hash,
@@ -249,13 +465,50 @@ namespace copy_tests {
     test::equal_to, test::cxx11_allocator<test::object, test::no_select_copy> >*
     test_map_no_select_copy;
 
+  boost::unordered_flat_set<int, test::hash, test::equal_to,
+    test::allocator1<int> >* test_set_trivially_copyable;
+  boost::unordered_flat_map<int, int, test::hash, test::equal_to,
+    test::allocator1<std::pair<int const, int> > >* test_map_trivially_copyable;
+
+  boost::unordered_flat_set<int, test::hash, test::equal_to,
+    std::allocator<int> >* test_set_trivially_copyable_std_allocator;
+  boost::unordered_flat_map<int, int, test::hash, test::equal_to,
+    std::allocator<std::pair<int const, int> > >*
+    test_map_trivially_copyable_std_allocator;
+
+  boost::unordered_flat_set<int, test::hash, test::equal_to, allocator<int> >*
+    test_set_trivially_copyable_no_construct;
+  boost::unordered_flat_map<int, int, test::hash, test::equal_to,
+    allocator<std::pair<int const, int> > >*
+    test_map_trivially_copyable_no_construct;
+
+  // clang-format off
   UNORDERED_TEST(copy_construct_tests1,
-    ((test_set)(test_map)(test_set_select_copy)(test_map_select_copy)(test_set_no_select_copy)(test_map_no_select_copy))(
+    ((test_set)(test_map)(test_set_select_copy)(test_map_select_copy)
-      (default_generator)(generate_collisions)(limited_range)))
+     (test_set_no_select_copy)(test_map_no_select_copy)
+     (test_set_trivially_copyable)(test_map_trivially_copyable))
+    ((default_generator)(generate_collisions)(limited_range)))
 
   UNORDERED_TEST(copy_construct_tests2,
-    ((test_set)(test_map)(test_set_select_copy)(test_map_select_copy)(test_set_no_select_copy)(test_map_no_select_copy))(
+    ((test_set)(test_map)(test_set_select_copy)(test_map_select_copy)
-      (default_generator)(generate_collisions)(limited_range)))
+     (test_set_no_select_copy)(test_map_no_select_copy)
+     (test_set_trivially_copyable)(test_map_trivially_copyable))
+    ((default_generator)(generate_collisions)(limited_range)))
+
+  UNORDERED_TEST(copy_construct_tests_std_allocator1,
+    ((test_set_trivially_copyable_std_allocator)
+     (test_map_trivially_copyable_std_allocator)
+     (test_set_trivially_copyable_no_construct)
+     (test_map_trivially_copyable_no_construct))
+    ((default_generator)(generate_collisions)(limited_range)))
+
+  UNORDERED_TEST(copy_construct_tests_std_allocator2,
+    ((test_set_trivially_copyable_std_allocator)
+     (test_map_trivially_copyable_std_allocator)
+     (test_set_trivially_copyable_no_construct)
+     (test_map_trivially_copyable_no_construct))
+    ((default_generator)(generate_collisions)(limited_range)))
+  // clang-format on
 #else
   boost::unordered_set<test::object, test::hash, test::equal_to,
     test::allocator1<test::object> >* test_set;