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Use aligned storage for the value.

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[SVN r49927]
This commit is contained in:
Daniel James
2008-11-24 23:15:55 +00:00
parent 601daa0e5d
commit c8e7874534
3 changed files with 51 additions and 140 deletions
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7
doc/changes.qbk
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@ -52,5 +52,12 @@ First official release.
* [@https://svn.boost.org/trac/boost/ticket/1710 Ticket 1710]: * [@https://svn.boost.org/trac/boost/ticket/1710 Ticket 1710]:
Use a larger prime number list. Thanks to Thorsten Ottosen and Hervé Use a larger prime number list. Thanks to Thorsten Ottosen and Hervé
Brönnimann. Brönnimann.
* Use
[@../../libs/type_traits/doc/html/boost_typetraits/category/alignment.html
aligned storage] to store the types. This changes the way the allocator is
used to construct nodes. It used to construct the node with two calls to
the allocator's `construct` method - once for the pointers and once for the
value. It now constructs the node with a single call to construct and
then constructs the value using in place construction.
[endsect] [endsect]

2
include/boost/unordered/detail/hash_table.hpp
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@ -26,6 +26,8 @@
#include <boost/static_assert.hpp> #include <boost/static_assert.hpp>
#include <boost/unordered/detail/allocator_helpers.hpp> #include <boost/unordered/detail/allocator_helpers.hpp>
#include <boost/type_traits/is_same.hpp> #include <boost/type_traits/is_same.hpp>
#include <boost/type_traits/aligned_storage.hpp>
#include <boost/type_traits/alignment_of.hpp>
#include <boost/mpl/if.hpp> #include <boost/mpl/if.hpp>
#include <boost/mpl/and.hpp> #include <boost/mpl/and.hpp>
#include <boost/detail/workaround.hpp> #include <boost/detail/workaround.hpp>

182
include/boost/unordered/detail/hash_table_impl.hpp
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@ -34,7 +34,6 @@ namespace boost {
public: public:
typedef BOOST_UNORDERED_TABLE_DATA data; typedef BOOST_UNORDERED_TABLE_DATA data;
struct node_base;
struct node; struct node;
struct bucket; struct bucket;
typedef std::size_t size_type; typedef std::size_t size_type;
@ -45,9 +44,6 @@ namespace boost {
typedef BOOST_DEDUCED_TYPENAME typedef BOOST_DEDUCED_TYPENAME
boost::unordered_detail::rebind_wrap<Alloc, node>::type boost::unordered_detail::rebind_wrap<Alloc, node>::type
node_allocator; node_allocator;
typedef BOOST_DEDUCED_TYPENAME
boost::unordered_detail::rebind_wrap<Alloc, node_base>::type
node_base_allocator;
typedef BOOST_DEDUCED_TYPENAME typedef BOOST_DEDUCED_TYPENAME
boost::unordered_detail::rebind_wrap<Alloc, bucket>::type boost::unordered_detail::rebind_wrap<Alloc, bucket>::type
bucket_allocator; bucket_allocator;
@ -88,39 +84,36 @@ namespace boost {
} }
}; };
// Value Base
struct value_base {
typename boost::aligned_storage<
sizeof(value_type),
boost::alignment_of<value_type>::value>::type data_;
void* address() { return this; }
};
// Hash Node // Hash Node
// //
// all no throw // all no throw
struct node_base : bucket struct node : value_base, bucket {
{
#if BOOST_UNORDERED_EQUIVALENT_KEYS #if BOOST_UNORDERED_EQUIVALENT_KEYS
public: public:
node_base() : group_prev_() node() : group_prev_()
{ {
BOOST_UNORDERED_MSVC_RESET_PTR(group_prev_); BOOST_UNORDERED_MSVC_RESET_PTR(group_prev_);
} }
link_ptr group_prev_; link_ptr group_prev_;
#endif #endif
value_type& value() {
return *static_cast<value_type*>(this->address());
}
}; };
struct node : node_base
{
public:
#if defined(BOOST_HAS_RVALUE_REFS) && defined(BOOST_HAS_VARIADIC_TMPL)
template <typename... Args>
node(Args&&... args)
: node_base(), value_(std::forward<Args>(args)...) {}
#else
node(value_type const& v) : node_base(), value_(v) {}
#endif
value_type value_;
};
#if defined(BOOST_HAS_RVALUE_REFS) && defined(BOOST_HAS_VARIADIC_TMPL)
// allocators // allocators
// //
// Stores all the allocators that we're going to need. // Stores all the allocators that we're going to need.
@ -136,7 +129,9 @@ namespace boost {
void destroy(link_ptr ptr) void destroy(link_ptr ptr)
{ {
node_ptr n(node_alloc_.address(*static_cast<node*>(&*ptr))); node* raw_ptr = static_cast<node*>(&*ptr);
raw_ptr->value().~value_type();
node_ptr n(node_alloc_.address(*raw_ptr));
node_alloc_.destroy(n); node_alloc_.destroy(n);
node_alloc_.deallocate(n, 1); node_alloc_.deallocate(n, 1);
} }
@ -163,146 +158,62 @@ namespace boost {
node_ptr node_; node_ptr node_;
bool node_constructed_; bool node_constructed_;
bool value_constructed_;
public: public:
node_constructor(allocators& a) node_constructor(allocators& a)
: allocators_(a), : allocators_(a),
node_(), node_constructed_(false) node_(), node_constructed_(false), value_constructed_(false)
{ {
} }
~node_constructor() ~node_constructor()
{ {
if (node_) { if (node_) {
if (value_constructed_) {
node_->value().~value_type();
}
if (node_constructed_) if (node_constructed_)
allocators_.node_alloc_.destroy(node_); allocators_.node_alloc_.destroy(node_);
allocators_.node_alloc_.deallocate(node_, 1); allocators_.node_alloc_.deallocate(node_, 1);
} }
} }
#if defined(BOOST_HAS_RVALUE_REFS) && defined(BOOST_HAS_VARIADIC_TMPL)
template <typename... Args> template <typename... Args>
void construct(Args&&... args) void construct(Args&&... args)
{ {
BOOST_ASSERT(!node_); BOOST_ASSERT(!node_);
node_constructed_ = false; node_constructed_ = false;
value_constructed_ = false;
node_ = allocators_.node_alloc_.allocate(1); node_ = allocators_.node_alloc_.allocate(1);
allocators_.node_alloc_.construct(node_, std::forward<Args>(args)...);
allocators_.node_alloc_.construct(node_, node());
node_constructed_ = true; node_constructed_ = true;
}
node_ptr get() const new(node_->address()) value_type(std::forward<Args>(args)...);
{ value_constructed_ = true;
BOOST_ASSERT(node_);
return node_;
} }
// no throw
link_ptr release()
{
node_ptr p = node_;
unordered_detail::reset(node_);
return link_ptr(allocators_.bucket_alloc_.address(*p));
}
private:
node_constructor(node_constructor const&);
node_constructor& operator=(node_constructor const&);
};
#else #else
// allocators
//
// Stores all the allocators that we're going to need.
struct allocators
{
node_allocator node_alloc_;
bucket_allocator bucket_alloc_;
value_allocator value_alloc_;
node_base_allocator node_base_alloc_;
allocators(value_allocator const& a)
: node_alloc_(a), bucket_alloc_(a),
value_alloc_(a), node_base_alloc_(a)
{}
void destroy(link_ptr ptr)
{
node_ptr n(node_alloc_.address(*static_cast<node*>(&*ptr)));
value_alloc_.destroy(value_alloc_.address(n->value_));
node_base_alloc_.destroy(node_base_alloc_.address(*n));
node_alloc_.deallocate(n, 1);
}
void swap(allocators& x)
{
boost::swap(node_alloc_, x.node_alloc_);
boost::swap(bucket_alloc_, x.bucket_alloc_);
boost::swap(value_alloc_, x.value_alloc_);
boost::swap(node_base_alloc_, x.node_base_alloc_);
}
bool operator==(allocators const& x)
{
return value_alloc_ == x.value_alloc_;
}
};
// node_constructor
//
// Used to construct nodes in an exception safe manner.
class node_constructor
{
allocators& allocators_;
node_ptr node_;
bool value_constructed_;
bool node_base_constructed_;
public:
node_constructor(allocators& a)
: allocators_(a),
node_(), value_constructed_(false), node_base_constructed_(false)
{
BOOST_UNORDERED_MSVC_RESET_PTR(node_);
}
~node_constructor()
{
if (node_) {
if (value_constructed_)
allocators_.value_alloc_.destroy(
allocators_.value_alloc_.address(node_->value_));
if (node_base_constructed_)
allocators_.node_base_alloc_.destroy(
allocators_.node_base_alloc_.address(*node_));
allocators_.node_alloc_.deallocate(node_, 1);
}
}
template <typename V> template <typename V>
void construct(V const& v) void construct(V const& v)
{ {
BOOST_ASSERT(!node_); BOOST_ASSERT(!node_);
node_constructed_ = false;
value_constructed_ = false; value_constructed_ = false;
node_base_constructed_ = false;
node_ = allocators_.node_alloc_.allocate(1); node_ = allocators_.node_alloc_.allocate(1);
allocators_.node_base_alloc_.construct( allocators_.node_alloc_.construct(node_, node());
allocators_.node_base_alloc_.address(*node_), node_constructed_ = true;
node_base());
node_base_constructed_ = true;
allocators_.value_alloc_.construct( new(node_->address()) value_type(v);
allocators_.value_alloc_.address(node_->value_), v);
value_constructed_ = true; value_constructed_ = true;
} }
#endif
node_ptr get() const node_ptr get() const
{ {
@ -322,7 +233,6 @@ namespace boost {
node_constructor(node_constructor const&); node_constructor(node_constructor const&);
node_constructor& operator=(node_constructor const&); node_constructor& operator=(node_constructor const&);
}; };
#endif
// Methods for navigating groups of elements with equal keys. // Methods for navigating groups of elements with equal keys.
@ -351,8 +261,7 @@ namespace boost {
// pre: Must be pointing to a node // pre: Must be pointing to a node
static inline reference get_value(link_ptr p) { static inline reference get_value(link_ptr p) {
BOOST_ASSERT(p); return get_node(p).value();
return static_cast<node*>(&*p)->value_;
} }
class iterator_base class iterator_base
@ -1357,17 +1266,10 @@ namespace boost {
// accessors // accessors
// no throw // no throw
#if defined(BOOST_HAS_RVALUE_REFS) && defined(BOOST_HAS_VARIADIC_TMPL)
node_allocator get_allocator() const node_allocator get_allocator() const
{ {
return data_.allocators_.node_alloc_; return data_.allocators_.node_alloc_;
} }
#else
value_allocator get_allocator() const
{
return data_.allocators_.value_alloc_;
}
#endif
// no throw // no throw
hasher const& hash_function() const hasher const& hash_function() const
@ -1728,7 +1630,7 @@ namespace boost {
iterator_base insert_impl(node_constructor& a) iterator_base insert_impl(node_constructor& a)
{ {
key_type const& k = extract_key(a.get()->value_); key_type const& k = extract_key(a.get()->value());
size_type hash_value = hash_function()(k); size_type hash_value = hash_function()(k);
bucket_ptr bucket = data_.bucket_ptr_from_hash(hash_value); bucket_ptr bucket = data_.bucket_ptr_from_hash(hash_value);
link_ptr position = find_iterator(bucket, k); link_ptr position = find_iterator(bucket, k);
@ -1750,7 +1652,7 @@ namespace boost {
iterator_base insert_hint_impl(iterator_base const& it, node_constructor& a) iterator_base insert_hint_impl(iterator_base const& it, node_constructor& a)
{ {
// equal can throw, but with no effects // equal can throw, but with no effects
if (it == data_.end() || !equal(extract_key(a.get()->value_), *it)) { if (it == data_.end() || !equal(extract_key(a.get()->value()), *it)) {
// Use the standard insert if the iterator doesn't point // Use the standard insert if the iterator doesn't point
// to a matching key. // to a matching key.
return insert_impl(a); return insert_impl(a);
@ -1766,7 +1668,7 @@ namespace boost {
// reserve has basic exception safety if the hash function // reserve has basic exception safety if the hash function
// throws, strong otherwise. // throws, strong otherwise.
bucket_ptr base = reserve_for_insert(size() + 1) ? bucket_ptr base = reserve_for_insert(size() + 1) ?
get_bucket(extract_key(a.get()->value_)) : it.bucket_; get_bucket(extract_key(a.get()->value())) : it.bucket_;
// Nothing after this point can throw // Nothing after this point can throw
@ -1796,7 +1698,7 @@ namespace boost {
for (; i != j; ++i) { for (; i != j; ++i) {
a.construct(*i); a.construct(*i);
key_type const& k = extract_key(a.get()->value_); key_type const& k = extract_key(a.get()->value());
bucket_ptr bucket = get_bucket(k); bucket_ptr bucket = get_bucket(k);
link_ptr position = find_iterator(bucket, k); link_ptr position = find_iterator(bucket, k);
@ -1981,7 +1883,7 @@ namespace boost {
a.construct(std::forward<Args>(args)...); a.construct(std::forward<Args>(args)...);
// No side effects in this initial code // No side effects in this initial code
key_type const& k = extract_key(a.get()->value_); key_type const& k = extract_key(a.get()->value());
size_type hash_value = hash_function()(k); size_type hash_value = hash_function()(k);
bucket_ptr bucket = data_.bucket_ptr_from_hash(hash_value); bucket_ptr bucket = data_.bucket_ptr_from_hash(hash_value);
link_ptr pos = find_iterator(bucket, k); link_ptr pos = find_iterator(bucket, k);