On 20/07/21 16:26 +0100, Jonathan Wakely wrote:
On 02/06/21 13:35 +0100, Jonathan Wakely wrote:
The allocator, hash function and equality function should all be
value-initialized by the default constructor of an unordered container.
Do it in the EBO helper, so we don't have to get it right in multiple
places.
Signed-off-by: Jonathan Wakely <jwak...@redhat.com>
libstdc++-v3/ChangeLog:
PR libstdc++/100863
PR libstdc++/65816
* include/bits/hashtable_policy.h (_Hashtable_ebo_helper):
Value-initialize subobject.
* testsuite/23_containers/unordered_map/allocator/default_init.cc:
Remove XFAIL.
* testsuite/23_containers/unordered_set/allocator/default_init.cc:
Remove XFAIL.
The recent change to _Hashtable_ebo_helper for this PR broke the
is_default_constructible trait for a hash container with a non-default
constructible allocator. That happens because the constructor needs to
be user-provided in order to initialize the member, and so is not
defined as deleted when the type is not default constructible.
By making _Hashtable derive from _Enable_special_members we can ensure
that the default constructor for the std::unordered_xxx containers is
deleted when it would be ill-formed. This makes the trait give the
correct answer.
Signed-off-by: Jonathan Wakely <jwak...@redhat.com>
libstdc++-v3/ChangeLog:
PR libstdc++/100863
* include/bits/hashtable.h (_Hashtable): Conditionally delete
default constructor by deriving from _Enable_special_members.
* testsuite/23_containers/unordered_map/cons/default.cc: New test.
* testsuite/23_containers/unordered_set/cons/default.cc: New test.
When I added the new mixin to _Hashtable, I forgot to explicitly
construct it in each non-default constructor. That means you can't
use any constructors unless all three of the hash function, equality
function, and allocator are all default constructible.
PR libstdc++/101583
* include/bits/hashtable.h (_Hashtable): Replace mixin with
_Enable_default_ctor. Construct it explicitly in all
non-forwarding, non-defaulted constructors.
* testsuite/23_containers/unordered_map/cons/default.cc: Check
non-default constructors can be used.
* testsuite/23_containers/unordered_set/cons/default.cc:
Likewise.
Tested powerpc64le-linux. Committed to trunk.
commit 8ed6cfbbee74ec9e03f2558b9c36f61dd7d4dcfd
Author: Jonathan Wakely <jwak...@redhat.com>
Date: Thu Jul 22 18:49:57 2021
libstdc++: Fix non-default constructors for hash containers [PR101583]
When I added the new mixin to _Hashtable, I forgot to explicitly
construct it in each non-default constructor. That means you can't
use any constructors unless all three of the hash function, equality
function, and allocator are all default constructible.
libstdc++-v3/ChangeLog:
PR libstdc++/101583
* include/bits/hashtable.h (_Hashtable): Replace mixin with
_Enable_default_ctor. Construct it explicitly in all
non-forwarding, non-defaulted constructors.
* testsuite/23_containers/unordered_map/cons/default.cc: Check
non-default constructors can be used.
* testsuite/23_containers/unordered_set/cons/default.cc:
Likewise.
diff --git a/libstdc++-v3/include/bits/hashtable.h b/libstdc++-v3/include/bits/hashtable.h
index adb59213f2d..92516b81ae5 100644
--- a/libstdc++-v3/include/bits/hashtable.h
+++ b/libstdc++-v3/include/bits/hashtable.h
@@ -54,11 +54,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// from any other potentially-overlapping subobjects of the hashtable.
template<typename _Equal, typename _Hash, typename _Allocator>
using _Hashtable_enable_default_ctor
- = _Enable_special_members<__and_<is_default_constructible<_Equal>,
+ = _Enable_default_constructor<__and_<is_default_constructible<_Equal>,
is_default_constructible<_Hash>,
is_default_constructible<_Allocator>>{},
- true, true, true, true, true,
- __detail::_Hash_node_base>;
+ __detail::_Hash_node_base>;
/**
* Primary class template _Hashtable.
@@ -228,6 +227,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_Equal, _Hash,
_RangeHash, _Unused,
_RehashPolicy, _Traits>;
+ using __enable_default_ctor
+ = _Hashtable_enable_default_ctor<_Equal, _Hash, _Alloc>;
public:
typedef _Key key_type;
@@ -484,7 +485,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_Hashtable(const _Hash& __h, const _Equal& __eq,
const allocator_type& __a)
: __hashtable_base(__h, __eq),
- __hashtable_alloc(__node_alloc_type(__a))
+ __hashtable_alloc(__node_alloc_type(__a)),
+ __enable_default_ctor(_Enable_default_constructor_tag{})
{ }
template<bool _No_realloc = true>
@@ -551,7 +553,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
explicit
_Hashtable(const allocator_type& __a)
- : __hashtable_alloc(__node_alloc_type(__a))
+ : __hashtable_alloc(__node_alloc_type(__a)),
+ __enable_default_ctor(_Enable_default_constructor_tag{})
{ }
template<typename _InputIterator>
@@ -1435,6 +1438,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__rehash_base(__ht),
__hashtable_alloc(
__node_alloc_traits::_S_select_on_copy(__ht._M_node_allocator())),
+ __enable_default_ctor(__ht),
_M_buckets(nullptr),
_M_bucket_count(__ht._M_bucket_count),
_M_element_count(__ht._M_element_count),
@@ -1457,6 +1461,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__map_base(__ht),
__rehash_base(__ht),
__hashtable_alloc(std::move(__a)),
+ __enable_default_ctor(__ht),
_M_buckets(__ht._M_buckets),
_M_bucket_count(__ht._M_bucket_count),
_M_before_begin(__ht._M_before_begin._M_nxt),
@@ -1487,6 +1492,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__map_base(__ht),
__rehash_base(__ht),
__hashtable_alloc(__node_alloc_type(__a)),
+ __enable_default_ctor(__ht),
_M_buckets(),
_M_bucket_count(__ht._M_bucket_count),
_M_element_count(__ht._M_element_count),
@@ -1508,6 +1514,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__map_base(__ht),
__rehash_base(__ht),
__hashtable_alloc(std::move(__a)),
+ __enable_default_ctor(__ht),
_M_buckets(nullptr),
_M_bucket_count(__ht._M_bucket_count),
_M_element_count(__ht._M_element_count),
diff --git a/libstdc++-v3/testsuite/23_containers/unordered_map/cons/default.cc b/libstdc++-v3/testsuite/23_containers/unordered_map/cons/default.cc
index e4f836fde3e..d64d078a7da 100644
--- a/libstdc++-v3/testsuite/23_containers/unordered_map/cons/default.cc
+++ b/libstdc++-v3/testsuite/23_containers/unordered_map/cons/default.cc
@@ -31,3 +31,18 @@ static_assert( ! std::is_default_constructible<Map2>{}, "PR libstdc++/100863" );
struct Equal : std::equal_to<int> { Equal(int) { } };
using Map3 = std::unordered_map<int, int, std::hash<int>, Equal>;
static_assert( ! std::is_default_constructible<Map3>{}, "PR libstdc++/100863" );
+
+// PR libstdc++/101583
+// verify non-default ctors can still be used
+using Map4 = std::unordered_map<int, int, Hash, Equal,
+ NoDefaultConsAlloc<std::pair<const int, int>>>;
+Hash h(1);
+Equal eq(1);
+Map4::allocator_type a(1);
+Map4 m{1, h, eq, a};
+Map4 m2{m.begin(), m.end(), m.size(), h, eq, a};
+Map4 m3{{{1,1}, {2,2}, {3,3}}, 3, h, eq, a};
+Map4 m4{m};
+Map4 m5{m, a};
+Map4 m6{std::move(m)};
+Map4 m7{std::move(m6), a};
diff --git a/libstdc++-v3/testsuite/23_containers/unordered_set/cons/default.cc b/libstdc++-v3/testsuite/23_containers/unordered_set/cons/default.cc
index 42fbf3d7997..41281d3d774 100644
--- a/libstdc++-v3/testsuite/23_containers/unordered_set/cons/default.cc
+++ b/libstdc++-v3/testsuite/23_containers/unordered_set/cons/default.cc
@@ -31,3 +31,17 @@ static_assert( ! std::is_default_constructible<Set2>{}, "PR libstdc++/100863" );
struct Equal : std::equal_to<int> { Equal(int) { } };
using Set3 = std::unordered_set<int, std::hash<int>, Equal>;
static_assert( ! std::is_default_constructible<Set3>{}, "PR libstdc++/100863" );
+
+// PR libstdc++/101583
+// verify non-default ctors can still be used
+using Set4 = std::unordered_set<int, Hash, Equal, NoDefaultConsAlloc<int>>;
+Hash h(1);
+Equal eq(1);
+Set4::allocator_type a(1);
+Set4 s{1, h, eq, a};
+Set4 s2{s.begin(), s.end(), s.size(), h, eq, a};
+Set4 s3{{1, 2, 3}, 3, h, eq, a};
+Set4 s4{s};
+Set4 s5{s, a};
+Set4 s6{std::move(s)};
+Set4 s7{std::move(s6), a};
