wip

parallel_hashmap/phmap.h

@@ -473,7 +473,7 @@ inline size_t GrowthToLowerboundCapacity(size_t growth)
     return growth + static_cast<size_t>((static_cast<int64_t>(growth) - 1) / 7);
 }
 
-namespace hashtable_debug_internal {
+namespace debug {
 
 // If it is a map, call get<0>().
 using std::get;
@@ -516,7 +516,7 @@ struct HashtableDebugAccess
     }
 };
 
-}  // namespace hashtable_debug_internal
+}  // namespace debug
 
 // ----------------------------------------------------------------------------
 //                    I N F O Z   S T U B S
@@ -1520,8 +1520,7 @@ public:
 
 private:
     template <class Container, typename Enabler>
-    friend struct phmap::container_internal::hashtable_debug_internal::
-    HashtableDebugAccess;
+    friend struct phmap::container_internal::debug::HashtableDebugAccess;
 
     struct FindElement 
     {
@@ -2196,14 +2195,14 @@ protected:
     // MutexLock with the additional set_mutex function, otherwise we could 
     // make the MutexLock from mutex.h a template and use that one.
     // --------------------------------------------------------------------
-    class SCOPED_LOCKABLE MutexLock_ {
+    class PHMAP_SCOPED_LOCKABLE MutexLock_ {
     public:
-        explicit MutexLock_(Mutex *mu) EXCLUSIVE_LOCK_FUNCTION(mu) : mu_(mu) {
+        explicit MutexLock_(Mutex *mu) PHMAP_EXCLUSIVE_LOCK_FUNCTION(mu) : mu_(mu) {
             if (this->mu_)
                 this->mu_->Lock();
         }
 
-        void set_mutex(Mutex *mu) NO_THREAD_SAFETY_ANALYSIS {
+        void set_mutex(Mutex *mu) PHMAP_NO_THREAD_SAFETY_ANALYSIS {
             assert(mu && this->mu_ == nullptr);
             this->mu_ = mu;
             this->mu_->Lock();
@@ -2214,7 +2213,7 @@ protected:
         MutexLock_& operator=(const MutexLock_&) = delete;
         MutexLock_& operator=(MutexLock_&&)      = delete;
 
-        ~MutexLock_() UNLOCK_FUNCTION() { if (this->mu_) this->mu_->Unlock(); }
+        ~MutexLock_() PHMAP_UNLOCK_FUNCTION() { if (this->mu_) this->mu_->Unlock(); }
 
     private:
         Mutex * mu_;
@@ -2998,8 +2997,7 @@ public:
 
 private:
     template <class Container, typename Enabler>
-    friend struct phmap::container_internal::hashtable_debug_internal::
-    HashtableDebugAccess;
+    friend struct phmap::container_internal::debug::HashtableDebugAccess;
 
     struct FindElement 
     {
@@ -3298,6 +3296,429 @@ private:
     }
 };
 
+// ----------------------------------------------------------------------------
+// Allocates at least n bytes aligned to the specified alignment.
+// Alignment must be a power of 2. It must be positive.
+//
+// Note that many allocators don't honor alignment requirements above certain
+// threshold (usually either alignof(std::max_align_t) or alignof(void*)).
+// Allocate() doesn't apply alignment corrections. If the underlying allocator
+// returns insufficiently alignment pointer, that's what you are going to get.
+// ----------------------------------------------------------------------------
+template <size_t Alignment, class Alloc>
+void* Allocate(Alloc* alloc, size_t n) {
+  static_assert(Alignment > 0, "");
+  assert(n && "n must be positive");
+  struct alignas(Alignment) M {};
+  using A = typename phmap::allocator_traits<Alloc>::template rebind_alloc<M>;
+  using AT = typename phmap::allocator_traits<Alloc>::template rebind_traits<M>;
+  A mem_alloc(*alloc);
+  void* p = AT::allocate(mem_alloc, (n + sizeof(M) - 1) / sizeof(M));
+  assert(reinterpret_cast<uintptr_t>(p) % Alignment == 0 &&
+         "allocator does not respect alignment");
+  return p;
+}
+
+// ----------------------------------------------------------------------------
+// The pointer must have been previously obtained by calling
+// Allocate<Alignment>(alloc, n).
+// ----------------------------------------------------------------------------
+template <size_t Alignment, class Alloc>
+void Deallocate(Alloc* alloc, void* p, size_t n) {
+  static_assert(Alignment > 0, "");
+  assert(n && "n must be positive");
+  struct alignas(Alignment) M {};
+  using A = typename phmap::allocator_traits<Alloc>::template rebind_alloc<M>;
+  using AT = typename phmap::allocator_traits<Alloc>::template rebind_traits<M>;
+  A mem_alloc(*alloc);
+  AT::deallocate(mem_alloc, static_cast<M*>(p),
+                 (n + sizeof(M) - 1) / sizeof(M));
+}
+
+namespace memory_internal {
+
+// Constructs T into uninitialized storage pointed by `ptr` using the args
+// specified in the tuple.
+// ----------------------------------------------------------------------------
+template <class Alloc, class T, class Tuple, size_t... I>
+void ConstructFromTupleImpl(Alloc* alloc, T* ptr, Tuple&& t,
+                            phmap::index_sequence<I...>) {
+    phmap::allocator_traits<Alloc>::construct(
+        *alloc, ptr, std::get<I>(std::forward<Tuple>(t))...);
+}
+
+template <class T, class F>
+struct WithConstructedImplF {
+    template <class... Args>
+    decltype(std::declval<F>()(std::declval<T>())) operator()(
+        Args&&... args) const {
+        return std::forward<F>(f)(T(std::forward<Args>(args)...));
+    }
+    F&& f;
+};
+
+template <class T, class Tuple, size_t... Is, class F>
+decltype(std::declval<F>()(std::declval<T>())) WithConstructedImpl(
+    Tuple&& t, phmap::index_sequence<Is...>, F&& f) {
+    return WithConstructedImplF<T, F>{std::forward<F>(f)}(
+        std::get<Is>(std::forward<Tuple>(t))...);
+}
+
+template <class T, size_t... Is>
+auto TupleRefImpl(T&& t, phmap::index_sequence<Is...>)
+    -> decltype(std::forward_as_tuple(std::get<Is>(std::forward<T>(t))...)) {
+  return std::forward_as_tuple(std::get<Is>(std::forward<T>(t))...);
+}
+
+// Returns a tuple of references to the elements of the input tuple. T must be a
+// tuple.
+// ----------------------------------------------------------------------------
+template <class T>
+auto TupleRef(T&& t) -> decltype(
+    TupleRefImpl(std::forward<T>(t),
+                 phmap::make_index_sequence<
+                     std::tuple_size<typename std::decay<T>::type>::value>())) {
+  return TupleRefImpl(
+      std::forward<T>(t),
+      phmap::make_index_sequence<
+          std::tuple_size<typename std::decay<T>::type>::value>());
+}
+
+template <class F, class K, class V>
+decltype(std::declval<F>()(std::declval<const K&>(), std::piecewise_construct,
+                           std::declval<std::tuple<K>>(), std::declval<V>()))
+DecomposePairImpl(F&& f, std::pair<std::tuple<K>, V> p) {
+    const auto& key = std::get<0>(p.first);
+    return std::forward<F>(f)(key, std::piecewise_construct, std::move(p.first),
+                              std::move(p.second));
+}
+
+}  // namespace memory_internal
+
+// Constructs T into uninitialized storage pointed by `ptr` using the args
+// specified in the tuple.
+// ----------------------------------------------------------------------------
+template <class Alloc, class T, class Tuple>
+void ConstructFromTuple(Alloc* alloc, T* ptr, Tuple&& t) {
+    memory_internal::ConstructFromTupleImpl(
+        alloc, ptr, std::forward<Tuple>(t),
+        phmap::make_index_sequence<
+        std::tuple_size<typename std::decay<Tuple>::type>::value>());
+}
+
+// Constructs T using the args specified in the tuple and calls F with the
+// constructed value.
+// ----------------------------------------------------------------------------
+template <class T, class Tuple, class F>
+decltype(std::declval<F>()(std::declval<T>())) WithConstructed(
+    Tuple&& t, F&& f) {
+    return memory_internal::WithConstructedImpl<T>(
+        std::forward<Tuple>(t),
+        phmap::make_index_sequence<
+        std::tuple_size<typename std::decay<Tuple>::type>::value>(),
+        std::forward<F>(f));
+}
+
+// ----------------------------------------------------------------------------
+// Given arguments of an std::pair's consructor, PairArgs() returns a pair of
+// tuples with references to the passed arguments. The tuples contain
+// constructor arguments for the first and the second elements of the pair.
+//
+// The following two snippets are equivalent.
+//
+// 1. std::pair<F, S> p(args...);
+//
+// 2. auto a = PairArgs(args...);
+//    std::pair<F, S> p(std::piecewise_construct,
+//                      std::move(p.first), std::move(p.second));
+// ----------------------------------------------------------------------------
+inline std::pair<std::tuple<>, std::tuple<>> PairArgs() { return {}; }
+
+template <class F, class S>
+std::pair<std::tuple<F&&>, std::tuple<S&&>> PairArgs(F&& f, S&& s) {
+  return {std::piecewise_construct, std::forward_as_tuple(std::forward<F>(f)),
+          std::forward_as_tuple(std::forward<S>(s))};
+}
+
+template <class F, class S>
+std::pair<std::tuple<const F&>, std::tuple<const S&>> PairArgs(
+    const std::pair<F, S>& p) {
+    return PairArgs(p.first, p.second);
+}
+
+template <class F, class S>
+std::pair<std::tuple<F&&>, std::tuple<S&&>> PairArgs(std::pair<F, S>&& p) {
+    return PairArgs(std::forward<F>(p.first), std::forward<S>(p.second));
+}
+
+template <class F, class S>
+auto PairArgs(std::piecewise_construct_t, F&& f, S&& s)
+    -> decltype(std::make_pair(memory_internal::TupleRef(std::forward<F>(f)),
+                               memory_internal::TupleRef(std::forward<S>(s)))) {
+    return std::make_pair(memory_internal::TupleRef(std::forward<F>(f)),
+                          memory_internal::TupleRef(std::forward<S>(s)));
+}
+
+// A helper function for implementing apply() in map policies.
+// ----------------------------------------------------------------------------
+template <class F, class... Args>
+auto DecomposePair(F&& f, Args&&... args)
+    -> decltype(memory_internal::DecomposePairImpl(
+        std::forward<F>(f), PairArgs(std::forward<Args>(args)...))) {
+    return memory_internal::DecomposePairImpl(
+        std::forward<F>(f), PairArgs(std::forward<Args>(args)...));
+}
+
+// A helper function for implementing apply() in set policies.
+// ----------------------------------------------------------------------------
+template <class F, class Arg>
+decltype(std::declval<F>()(std::declval<const Arg&>(), std::declval<Arg>()))
+DecomposeValue(F&& f, Arg&& arg) {
+    const auto& key = arg;
+    return std::forward<F>(f)(key, std::forward<Arg>(arg));
+}
+
+// Helper functions for asan and msan.
+// ----------------------------------------------------------------------------
+inline void SanitizerPoisonMemoryRegion(const void* m, size_t s) {
+#ifdef ADDRESS_SANITIZER
+    ASAN_POISON_MEMORY_REGION(m, s);
+#endif
+#ifdef MEMORY_SANITIZER
+    __msan_poison(m, s);
+#endif
+    (void)m;
+    (void)s;
+}
+
+inline void SanitizerUnpoisonMemoryRegion(const void* m, size_t s) {
+#ifdef ADDRESS_SANITIZER
+    ASAN_UNPOISON_MEMORY_REGION(m, s);
+#endif
+#ifdef MEMORY_SANITIZER
+    __msan_unpoison(m, s);
+#endif
+    (void)m;
+    (void)s;
+}
+
+template <typename T>
+inline void SanitizerPoisonObject(const T* object) {
+    SanitizerPoisonMemoryRegion(object, sizeof(T));
+}
+
+template <typename T>
+inline void SanitizerUnpoisonObject(const T* object) {
+    SanitizerUnpoisonMemoryRegion(object, sizeof(T));
+}
+
+namespace memory_internal {
+
+// ----------------------------------------------------------------------------
+// If Pair is a standard-layout type, OffsetOf<Pair>::kFirst and
+// OffsetOf<Pair>::kSecond are equivalent to offsetof(Pair, first) and
+// offsetof(Pair, second) respectively. Otherwise they are -1.
+//
+// The purpose of OffsetOf is to avoid calling offsetof() on non-standard-layout
+// type, which is non-portable.
+// ----------------------------------------------------------------------------
+template <class Pair, class = std::true_type>
+struct OffsetOf {
+  static constexpr size_t kFirst = -1;
+  static constexpr size_t kSecond = -1;
+};
+
+template <class Pair>
+struct OffsetOf<Pair, typename std::is_standard_layout<Pair>::type> 
+{
+    static constexpr size_t kFirst = offsetof(Pair, first);
+    static constexpr size_t kSecond = offsetof(Pair, second);
+};
+
+// ----------------------------------------------------------------------------
+template <class K, class V>
+struct IsLayoutCompatible 
+{
+private:
+    struct Pair {
+        K first;
+        V second;
+    };
+
+    // Is P layout-compatible with Pair?
+    template <class P>
+    static constexpr bool LayoutCompatible() {
+        return std::is_standard_layout<P>() && sizeof(P) == sizeof(Pair) &&
+            alignof(P) == alignof(Pair) &&
+            memory_internal::OffsetOf<P>::kFirst ==
+            memory_internal::OffsetOf<Pair>::kFirst &&
+            memory_internal::OffsetOf<P>::kSecond ==
+            memory_internal::OffsetOf<Pair>::kSecond;
+    }
+
+public:
+    // Whether pair<const K, V> and pair<K, V> are layout-compatible. If they are,
+    // then it is safe to store them in a union and read from either.
+    static constexpr bool value = std::is_standard_layout<K>() &&
+        std::is_standard_layout<Pair>() &&
+        memory_internal::OffsetOf<Pair>::kFirst == 0 &&
+        LayoutCompatible<std::pair<K, V>>() &&
+        LayoutCompatible<std::pair<const K, V>>();
+};
+
+}  // namespace memory_internal
+
+// ----------------------------------------------------------------------------
+// The internal storage type for key-value containers like flat_hash_map.
+//
+// It is convenient for the value_type of a flat_hash_map<K, V> to be
+// pair<const K, V>; the "const K" prevents accidental modification of the key
+// when dealing with the reference returned from find() and similar methods.
+// However, this creates other problems; we want to be able to emplace(K, V)
+// efficiently with move operations, and similarly be able to move a
+// pair<K, V> in insert().
+//
+// The solution is this union, which aliases the const and non-const versions
+// of the pair. This also allows flat_hash_map<const K, V> to work, even though
+// that has the same efficiency issues with move in emplace() and insert() -
+// but people do it anyway.
+//
+// If kMutableKeys is false, only the value member can be accessed.
+//
+// If kMutableKeys is true, key can be accessed through all slots while value
+// and mutable_value must be accessed only via INITIALIZED slots. Slots are
+// created and destroyed via mutable_value so that the key can be moved later.
+//
+// Accessing one of the union fields while the other is active is safe as
+// long as they are layout-compatible, which is guaranteed by the definition of
+// kMutableKeys. For C++11, the relevant section of the standard is
+// https://timsong-cpp.github.io/cppwp/n3337/class.mem#19 (9.2.19)
+// ----------------------------------------------------------------------------
+template <class K, class V>
+union map_slot_type 
+{
+    map_slot_type() {}
+    ~map_slot_type() = delete;
+    using value_type = std::pair<const K, V>;
+    using mutable_value_type = std::pair<K, V>;
+
+    value_type value;
+    mutable_value_type mutable_value;
+    K key;
+};
+
+// ----------------------------------------------------------------------------
+// ----------------------------------------------------------------------------
+template <class K, class V>
+struct map_slot_policy 
+{
+    using slot_type = map_slot_type<K, V>;
+    using value_type = std::pair<const K, V>;
+    using mutable_value_type = std::pair<K, V>;
+
+private:
+    static void emplace(slot_type* slot) {
+        // The construction of union doesn't do anything at runtime but it allows us
+        // to access its members without violating aliasing rules.
+        new (slot) slot_type;
+    }
+    // If pair<const K, V> and pair<K, V> are layout-compatible, we can accept one
+    // or the other via slot_type. We are also free to access the key via
+    // slot_type::key in this case.
+    using kMutableKeys = memory_internal::IsLayoutCompatible<K, V>;
+
+public:
+    static value_type& element(slot_type* slot) { return slot->value; }
+    static const value_type& element(const slot_type* slot) {
+        return slot->value;
+    }
+
+    static const K& key(const slot_type* slot) {
+        return kMutableKeys::value ? slot->key : slot->value.first;
+    }
+
+    template <class Allocator, class... Args>
+    static void construct(Allocator* alloc, slot_type* slot, Args&&... args) {
+        emplace(slot);
+        if (kMutableKeys::value) {
+            phmap::allocator_traits<Allocator>::construct(*alloc, &slot->mutable_value,
+                                                         std::forward<Args>(args)...);
+        } else {
+            phmap::allocator_traits<Allocator>::construct(*alloc, &slot->value,
+                                                         std::forward<Args>(args)...);
+        }
+    }
+
+    // Construct this slot by moving from another slot.
+    template <class Allocator>
+    static void construct(Allocator* alloc, slot_type* slot, slot_type* other) {
+        emplace(slot);
+        if (kMutableKeys::value) {
+            phmap::allocator_traits<Allocator>::construct(
+                *alloc, &slot->mutable_value, std::move(other->mutable_value));
+        } else {
+            phmap::allocator_traits<Allocator>::construct(*alloc, &slot->value,
+                                                         std::move(other->value));
+        }
+    }
+
+    template <class Allocator>
+    static void destroy(Allocator* alloc, slot_type* slot) {
+        if (kMutableKeys::value) {
+            phmap::allocator_traits<Allocator>::destroy(*alloc, &slot->mutable_value);
+        } else {
+            phmap::allocator_traits<Allocator>::destroy(*alloc, &slot->value);
+        }
+    }
+
+    template <class Allocator>
+    static void transfer(Allocator* alloc, slot_type* new_slot,
+                         slot_type* old_slot) {
+        emplace(new_slot);
+        if (kMutableKeys::value) {
+            phmap::allocator_traits<Allocator>::construct(
+                *alloc, &new_slot->mutable_value, std::move(old_slot->mutable_value));
+        } else {
+            phmap::allocator_traits<Allocator>::construct(*alloc, &new_slot->value,
+                                                         std::move(old_slot->value));
+        }
+        destroy(alloc, old_slot);
+    }
+
+    template <class Allocator>
+    static void swap(Allocator* alloc, slot_type* a, slot_type* b) {
+        if (kMutableKeys::value) {
+            using std::swap;
+            swap(a->mutable_value, b->mutable_value);
+        } else {
+            value_type tmp = std::move(a->value);
+            phmap::allocator_traits<Allocator>::destroy(*alloc, &a->value);
+            phmap::allocator_traits<Allocator>::construct(*alloc, &a->value,
+                                                         std::move(b->value));
+            phmap::allocator_traits<Allocator>::destroy(*alloc, &b->value);
+            phmap::allocator_traits<Allocator>::construct(*alloc, &b->value,
+                                                         std::move(tmp));
+        }
+    }
+
+    template <class Allocator>
+    static void move(Allocator* alloc, slot_type* src, slot_type* dest) {
+        if (kMutableKeys::value) {
+            dest->mutable_value = std::move(src->mutable_value);
+        } else {
+            phmap::allocator_traits<Allocator>::destroy(*alloc, &dest->value);
+            phmap::allocator_traits<Allocator>::construct(*alloc, &dest->value,
+                                                          std::move(src->value));
+        }
+    }
+
+    template <class Allocator>
+    static void move(Allocator* alloc, slot_type* first, slot_type* last,
+                     slot_type* result) {
+        for (slot_type *src = first, *dest = result; src != last; ++src, ++dest)
+            move(alloc, src, dest);
+    }
+};
 
 // --------------------------------------------------------------------------
 // Policy: a policy defines how to perform different operations on
@@ -3400,6 +3821,46 @@ struct FlatHashMapPolicy
     static const V& value(const std::pair<const K, V>* kv) { return kv->second; }
 };
 
+template <class Reference, class Policy>
+struct node_hash_policy {
+    static_assert(std::is_lvalue_reference<Reference>::value, "");
+
+    using slot_type = typename std::remove_cv<
+        typename std::remove_reference<Reference>::type>::type*;
+
+    template <class Alloc, class... Args>
+    static void construct(Alloc* alloc, slot_type* slot, Args&&... args) {
+        *slot = Policy::new_element(alloc, std::forward<Args>(args)...);
+    }
+
+    template <class Alloc>
+    static void destroy(Alloc* alloc, slot_type* slot) {
+        Policy::delete_element(alloc, *slot);
+    }
+
+    template <class Alloc>
+    static void transfer(Alloc*, slot_type* new_slot, slot_type* old_slot) {
+        *new_slot = *old_slot;
+    }
+
+    static size_t space_used(const slot_type* slot) {
+        if (slot == nullptr) return Policy::element_space_used(nullptr);
+        return Policy::element_space_used(*slot);
+    }
+
+    static Reference element(slot_type* slot) { return **slot; }
+
+    template <class T, class P = Policy>
+    static auto value(T* elem) -> decltype(P::value(elem)) {
+        return P::value(elem);
+    }
+
+    template <class... Ts, class P = Policy>
+    static auto apply(Ts&&... ts) -> decltype(P::apply(std::forward<Ts>(ts)...)) {
+        return P::apply(std::forward<Ts>(ts)...);
+    }
+};
+
 // --------------------------------------------------------------------------
 // --------------------------------------------------------------------------
 template <class T>