2014-09-06 François Dumont <fdumont@gcc.gnu.org>

	* include/bits/hashtable_policy.h (_Prime_rehash_policy): Constructor
	noexcept qualified.
	(_Hash_code_base<>): All specialization default constructible if
	possible.
	(_Hashtable_base<>): Likewise.
	* include/bits/hashtable.h (_Hashtable<>()): Implementation defaulted.
	* include/bits/unordered_map.h (unordered_map<>::unordered_map()): New,
	implementation defaulted.
	(unordered_multimap<>::unordered_multimap()): Likewise.
	* include/bits/unordered_set.h
	(unordered_set<>::unordered_set()): Likewise.
	(unordered_multiset<>::unordered_multiset()): Likewise.
	* include/debug/unordered_map: Likewise.
	* include/debug/unordered_set: Likewise.
	* testsuite/23_containers/unordered_map/allocator/noexcept.cc
	(test04()): New.
	* testsuite/23_containers/unordered_multimap/allocator/noexcept.cc
	(test04()): New.
	* testsuite/23_containers/unordered_set/allocator/noexcept.cc
	(test04()): New.
	* testsuite/23_containers/unordered_multiset/allocator/noexcept.cc
	(test04()): New.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@214986 138bc75d-0d04-0410-961f-82ee72b054a4

4 files changed, 63 insertions, 38 deletions

diff --git a/libstdc++-v3/include/bits/hashtable.h b/libstdc++-v3/include/bits/hashtable.h
index 588e69c9d4d..0eb58cfb6ed 100644
--- a/libstdc++-v3/include/bits/hashtable.h
+++ b/libstdc++-v3/include/bits/hashtable.h
@@ -310,10 +310,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 				   const_local_iterator;
 
     private:
-      __bucket_type*		_M_buckets;
-      size_type			_M_bucket_count;
+      __bucket_type*		_M_buckets		= &_M_single_bucket;
+      size_type			_M_bucket_count		= 1;
       __node_base		_M_before_begin;
-      size_type			_M_element_count;
+      size_type			_M_element_count	= 0;
       _RehashPolicy		_M_rehash_policy;
 
       // A single bucket used when only need for 1 bucket. Especially
@@ -322,7 +322,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       // qualified.
       // Note that we can't leave hashtable with 0 bucket without adding
       // numerous checks in the code to avoid 0 modulus.
-      __bucket_type		_M_single_bucket;
+      __bucket_type		_M_single_bucket	= nullptr;
 
       bool
       _M_uses_single_bucket(__bucket_type* __bkts) const
@@ -382,8 +382,16 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       void
       _M_reset() noexcept;
 
+      _Hashtable(const _H1& __h1, const _H2& __h2, const _Hash& __h,
+		 const _Equal& __eq, const _ExtractKey& __exk,
+		 const allocator_type& __a)
+	: __hashtable_base(__exk, __h1, __h2, __h, __eq),
+	  __hashtable_alloc(__node_alloc_type(__a))
+      { }
+
     public:
       // Constructor, destructor, assignment, swap
+      _Hashtable() = default;
       _Hashtable(size_type __bucket_hint,
 		 const _H1&, const _H2&, const _Hash&,
 		 const _Equal&, const _ExtractKey&,
@@ -407,12 +415,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       // Use delegating constructors.
       explicit
       _Hashtable(const allocator_type& __a)
-      : _Hashtable(10, _H1(), _H2(), _Hash(), key_equal(),
-		   __key_extract(), __a)
+	: __hashtable_alloc(__node_alloc_type(__a))
       { }
 
       explicit
-      _Hashtable(size_type __n = 10,
+      _Hashtable(size_type __n,
 		 const _H1& __hf = _H1(),
 		 const key_equal& __eql = key_equal(),
 		 const allocator_type& __a = allocator_type())
@@ -791,15 +798,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	       const _H1& __h1, const _H2& __h2, const _Hash& __h,
 	       const _Equal& __eq, const _ExtractKey& __exk,
 	       const allocator_type& __a)
-    : __hashtable_base(__exk, __h1, __h2, __h, __eq),
-      __map_base(),
-      __rehash_base(),
-      __hashtable_alloc(__node_alloc_type(__a)),
-      _M_element_count(0),
-      _M_rehash_policy()
+      : _Hashtable(__h1, __h2, __h, __eq, __exk, __a)
     {
-      _M_bucket_count = _M_rehash_policy._M_next_bkt(__bucket_hint);
-      _M_buckets = _M_allocate_buckets(_M_bucket_count);
+      auto __bkt = _M_rehash_policy._M_next_bkt(__bucket_hint);
+      if (__bkt > _M_bucket_count)
+	{
+	  _M_buckets = _M_allocate_buckets(__bkt);
+	  _M_bucket_count = __bkt;
+	}
     }
 
   template<typename _Key, typename _Value,
@@ -814,20 +820,20 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 		 const _H1& __h1, const _H2& __h2, const _Hash& __h,
 		 const _Equal& __eq, const _ExtractKey& __exk,
 		 const allocator_type& __a)
-      : __hashtable_base(__exk, __h1, __h2, __h, __eq),
-	__map_base(),
-	__rehash_base(),
-	__hashtable_alloc(__node_alloc_type(__a)),
-	_M_element_count(0),
-	_M_rehash_policy()
+	: _Hashtable(__h1, __h2, __h, __eq, __exk, __a)
       {
 	auto __nb_elems = __detail::__distance_fw(__f, __l);
-	_M_bucket_count =
+	auto __bkt_count =
 	  _M_rehash_policy._M_next_bkt(
 	    std::max(_M_rehash_policy._M_bkt_for_elements(__nb_elems),
 		     __bucket_hint));
 
-	_M_buckets = _M_allocate_buckets(_M_bucket_count);
+	if (__bkt_count > _M_bucket_count)
+	  {
+	    _M_buckets = _M_allocate_buckets(__bkt_count);
+	    _M_bucket_count = __bkt_count;
+	  }
+
 	__try
 	  {
 	    for (; __f != __l; ++__f)
@@ -1101,7 +1107,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       __rehash_base(__ht),
       __hashtable_alloc(
 	__node_alloc_traits::_S_select_on_copy(__ht._M_node_allocator())),
-      _M_buckets(),
+      _M_buckets(nullptr),
       _M_bucket_count(__ht._M_bucket_count),
       _M_element_count(__ht._M_element_count),
       _M_rehash_policy(__ht._M_rehash_policy)
@@ -1175,7 +1181,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       __map_base(__ht),
       __rehash_base(__ht),
       __hashtable_alloc(__node_alloc_type(__a)),
-      _M_buckets(),
+      _M_buckets(nullptr),
       _M_bucket_count(__ht._M_bucket_count),
       _M_element_count(__ht._M_element_count),
       _M_rehash_policy(__ht._M_rehash_policy)
@@ -1218,8 +1224,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     ~_Hashtable() noexcept
     {
       clear();
-      if (_M_buckets)
-	_M_deallocate_buckets();
+      _M_deallocate_buckets();
     }
 
   template<typename _Key, typename _Value,
diff --git a/libstdc++-v3/include/bits/hashtable_policy.h b/libstdc++-v3/include/bits/hashtable_policy.h
index 606fbabbcdf..74d1bd011cf 100644
--- a/libstdc++-v3/include/bits/hashtable_policy.h
+++ b/libstdc++-v3/include/bits/hashtable_policy.h
@@ -460,7 +460,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
   /// smallest prime that keeps the load factor small enough.
   struct _Prime_rehash_policy
   {
-    _Prime_rehash_policy(float __z = 1.0)
+    _Prime_rehash_policy(float __z = 1.0) noexcept
     : _M_max_load_factor(__z), _M_next_resize(0) { }
 
     float
@@ -1071,7 +1071,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       typedef void* 					__hash_code;
       typedef _Hash_node<_Value, false>			__node_type;
 
-      // We need the default constructor for the local iterators.
+      // We need the default constructor for the local iterators and _Hashtable
+      // default constructor.
       _Hash_code_base() = default;
 
       _Hash_code_base(const _ExtractKey& __ex, const _H1&, const _H2&,
@@ -1161,7 +1162,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       typedef std::size_t 				__hash_code;
       typedef _Hash_node<_Value, false>			__node_type;
 
-      // We need the default constructor for the local iterators.
+      // We need the default constructor for the local iterators and _Hashtable
+      // default constructor.
       _Hash_code_base() = default;
 
       _Hash_code_base(const _ExtractKey& __ex,
@@ -1250,6 +1252,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       typedef std::size_t 				__hash_code;
       typedef _Hash_node<_Value, true>			__node_type;
 
+      // We need the default constructor for _Hashtable default constructor.
+      _Hash_code_base() = default;
       _Hash_code_base(const _ExtractKey& __ex,
 		      const _H1& __h1, const _H2& __h2,
 		      const _Default_ranged_hash&)
@@ -1694,6 +1698,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 					__hash_code, __hash_cached::value>;
 
   protected:
+    _Hashtable_base() = default;
     _Hashtable_base(const _ExtractKey& __ex, const _H1& __h1, const _H2& __h2,
 		    const _Hash& __hash, const _Equal& __eq)
     : __hash_code_base(__ex, __h1, __h2, __hash), _EqualEBO(__eq)
@@ -1906,6 +1911,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	__alloc_rebind<__node_alloc_type, __bucket_type>;
       using __bucket_alloc_traits = std::allocator_traits<__bucket_alloc_type>;
 
+      _Hashtable_alloc() = default;
       _Hashtable_alloc(const _Hashtable_alloc&) = default;
       _Hashtable_alloc(_Hashtable_alloc&&) = default;
 
diff --git a/libstdc++-v3/include/bits/unordered_map.h b/libstdc++-v3/include/bits/unordered_map.h
index 580aed9cc5c..019201d1dcc 100644
--- a/libstdc++-v3/include/bits/unordered_map.h
+++ b/libstdc++-v3/include/bits/unordered_map.h
@@ -128,15 +128,18 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
 
       //construct/destroy/copy
 
+      /// Default constructor.
+      unordered_map() = default;
+
       /**
        *  @brief  Default constructor creates no elements.
-       *  @param __n  Initial number of buckets.
+       *  @param __n  Minimal initial number of buckets.
        *  @param __hf  A hash functor.
        *  @param __eql  A key equality functor.
        *  @param __a  An allocator object.
        */
       explicit
-      unordered_map(size_type __n = 10,
+      unordered_map(size_type __n,
 		    const hasher& __hf = hasher(),
 		    const key_equal& __eql = key_equal(),
 		    const allocator_type& __a = allocator_type())
@@ -840,15 +843,18 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
 
       //construct/destroy/copy
 
+      /// Default constructor.
+      unordered_multimap() = default;
+
       /**
        *  @brief  Default constructor creates no elements.
-       *  @param __n  Initial number of buckets.
+       *  @param __n  Mnimal initial number of buckets.
        *  @param __hf  A hash functor.
        *  @param __eql  A key equality functor.
        *  @param __a  An allocator object.
        */
       explicit
-      unordered_multimap(size_type __n = 10,
+      unordered_multimap(size_type __n,
 			 const hasher& __hf = hasher(),
 			 const key_equal& __eql = key_equal(),
 			 const allocator_type& __a = allocator_type())
diff --git a/libstdc++-v3/include/bits/unordered_set.h b/libstdc++-v3/include/bits/unordered_set.h
index 3cf248d7d1c..161c6fbbe61 100644
--- a/libstdc++-v3/include/bits/unordered_set.h
+++ b/libstdc++-v3/include/bits/unordered_set.h
@@ -121,15 +121,19 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
       //@}
 
       // construct/destroy/copy
+
+      /// Default constructor.
+      unordered_set() = default;
+
       /**
        *  @brief  Default constructor creates no elements.
-       *  @param __n  Initial number of buckets.
+       *  @param __n  Minimal initial number of buckets.
        *  @param __hf  A hash functor.
        *  @param __eql  A key equality functor.
        *  @param __a  An allocator object.
        */
       explicit
-      unordered_set(size_type __n = 10,
+      unordered_set(size_type __n,
 		    const hasher& __hf = hasher(),
 		    const key_equal& __eql = key_equal(),
 		    const allocator_type& __a = allocator_type())
@@ -756,15 +760,19 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
       //@}
 
       // construct/destroy/copy
+
+      /// Default constructor.
+      unordered_multiset() = default;
+
       /**
        *  @brief  Default constructor creates no elements.
-       *  @param __n  Initial number of buckets.
+       *  @param __n  Minimal initial number of buckets.
        *  @param __hf  A hash functor.
        *  @param __eql  A key equality functor.
        *  @param __a  An allocator object.
        */
       explicit
-      unordered_multiset(size_type __n = 10,
+      unordered_multiset(size_type __n,
 			 const hasher& __hf = hasher(),
 			 const key_equal& __eql = key_equal(),
 			 const allocator_type& __a = allocator_type())