Hi
Here is a proposal to fix PR 61143. As explained in the PR I
finally prefer to leave the container in a valid state that is to say
with a non zero number of bucket, that is to say 1, after a move. This
bucket is stored directly in the container so not allocated to leave the
move operations noexcept qualified. With this evolution we could even
make the default constructor noexcept but I don't think it has any interest.
2014-05-15 François Dumont <fdum...@gcc.gnu.org>
PR libstdc++/61143
* include/bits/hashtable.h: Fix move semantic to leave hashtable in a
usable state.
* testsuite/23_containers/unordered_set/61143.cc: New.
I run unordered containers test for the moment with no error. I
will run the others before to commit.
François
Index: include/bits/hashtable.h
===================================================================
--- include/bits/hashtable.h (revision 210479)
+++ include/bits/hashtable.h (working copy)
@@ -316,14 +316,37 @@
size_type _M_element_count;
_RehashPolicy _M_rehash_policy;
+ // A single bucket used when only need 1 bucket. After move the hashtable
+ // is left with only 1 bucket which is not allocated so that we can have a
+ // noexcept move constructor.
+ // 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;
+
__hashtable_alloc&
_M_base_alloc() { return *this; }
- using __hashtable_alloc::_M_deallocate_buckets;
+ __bucket_type*
+ _M_allocate_buckets(size_type __n)
+ {
+ if (__builtin_expect(__n == 1, false))
+ return &_M_single_bucket;
+ return __hashtable_alloc::_M_allocate_buckets(__n);
+ }
+
void
+ _M_deallocate_buckets(__bucket_type* __bkts, size_type __n)
+ {
+ if (__builtin_expect(__bkts == &_M_single_bucket, false))
+ return;
+
+ __hashtable_alloc::_M_deallocate_buckets(__bkts, __n);
+ }
+
+ void
_M_deallocate_buckets()
- { this->_M_deallocate_buckets(_M_buckets, _M_bucket_count); }
+ { _M_deallocate_buckets(_M_buckets, _M_bucket_count); }
// Gets bucket begin, deals with the fact that non-empty buckets contain
// their before begin node.
@@ -703,11 +726,7 @@
size_type
erase(const key_type& __k)
- {
- if (__builtin_expect(_M_bucket_count == 0, false))
- return 0;
- return _M_erase(__unique_keys(), __k);
- }
+ { return _M_erase(__unique_keys(), __k); }
iterator
erase(const_iterator, const_iterator);
@@ -768,7 +787,7 @@
_M_rehash_policy()
{
_M_bucket_count = _M_rehash_policy._M_next_bkt(__bucket_hint);
- _M_buckets = this->_M_allocate_buckets(_M_bucket_count);
+ _M_buckets = _M_allocate_buckets(_M_bucket_count);
}
template<typename _Key, typename _Value,
@@ -796,7 +815,7 @@
std::max(_M_rehash_policy._M_bkt_for_elements(__nb_elems),
__bucket_hint));
- _M_buckets = this->_M_allocate_buckets(_M_bucket_count);
+ _M_buckets = _M_allocate_buckets(_M_bucket_count);
__try
{
for (; __f != __l; ++__f)
@@ -833,9 +852,9 @@
{
// Replacement allocator cannot free existing storage.
this->_M_deallocate_nodes(_M_begin());
- if (__builtin_expect(_M_bucket_count != 0, true))
- _M_deallocate_buckets();
- _M_reset();
+ _M_before_begin._M_nxt = nullptr;
+ _M_deallocate_buckets();
+ _M_buckets = nullptr;
std::__alloc_on_copy(__this_alloc, __that_alloc);
__hashtable_base::operator=(__ht);
_M_bucket_count = __ht._M_bucket_count;
@@ -867,7 +886,7 @@
if (_M_bucket_count != __ht._M_bucket_count)
{
__former_buckets = _M_buckets;
- _M_buckets = this->_M_allocate_buckets(__ht._M_bucket_count);
+ _M_buckets = _M_allocate_buckets(__ht._M_bucket_count);
_M_bucket_count = __ht._M_bucket_count;
}
else
@@ -885,8 +904,7 @@
[&__roan](const __node_type* __n)
{ return __roan(__n->_M_v()); });
if (__former_buckets)
- this->_M_deallocate_buckets(__former_buckets,
- __former_bucket_count);
+ _M_deallocate_buckets(__former_buckets, __former_bucket_count);
}
__catch(...)
{
@@ -917,7 +935,7 @@
{
__bucket_type* __buckets = nullptr;
if (!_M_buckets)
- _M_buckets = __buckets = this->_M_allocate_buckets(_M_bucket_count);
+ _M_buckets = __buckets = _M_allocate_buckets(_M_bucket_count);
__try
{
@@ -964,8 +982,9 @@
_M_reset() noexcept
{
_M_rehash_policy._M_reset();
- _M_bucket_count = 0;
- _M_buckets = nullptr;
+ _M_bucket_count = 1;
+ _M_buckets = &_M_single_bucket;
+ _M_single_bucket = nullptr;
_M_before_begin._M_nxt = nullptr;
_M_element_count = 0;
}
@@ -980,12 +999,16 @@
_M_move_assign(_Hashtable&& __ht, std::true_type)
{
this->_M_deallocate_nodes(_M_begin());
- if (__builtin_expect(_M_bucket_count != 0, true))
- _M_deallocate_buckets();
-
+ _M_deallocate_buckets();
__hashtable_base::operator=(std::move(__ht));
_M_rehash_policy = __ht._M_rehash_policy;
- _M_buckets = __ht._M_buckets;
+ if (__builtin_expect(__ht._M_buckets != &__ht._M_single_bucket, true))
+ _M_buckets = __ht._M_buckets;
+ else
+ {
+ _M_buckets = &_M_single_bucket;
+ _M_single_bucket = __ht._M_single_bucket;
+ }
_M_bucket_count = __ht._M_bucket_count;
_M_before_begin._M_nxt = __ht._M_before_begin._M_nxt;
_M_element_count = __ht._M_element_count;
@@ -1019,7 +1042,7 @@
if (_M_bucket_count != __ht._M_bucket_count)
{
__former_buckets = _M_buckets;
- _M_buckets = this->_M_allocate_buckets(__ht._M_bucket_count);
+ _M_buckets = _M_allocate_buckets(__ht._M_bucket_count);
_M_bucket_count = __ht._M_bucket_count;
}
else
@@ -1093,10 +1116,18 @@
_M_element_count(__ht._M_element_count),
_M_rehash_policy(__ht._M_rehash_policy)
{
+ // Update, if necessary, buckets if __ht is using its single bucket.
+ if (__builtin_expect(__ht._M_buckets == &__ht._M_single_bucket, false))
+ {
+ _M_buckets = &_M_single_bucket;
+ _M_single_bucket = __ht._M_single_bucket;
+ }
+
// Update, if necessary, bucket pointing to before begin that hasn't
// moved.
if (_M_begin())
_M_buckets[_M_bucket_index(_M_begin())] = &_M_before_begin;
+
__ht._M_reset();
}
@@ -1139,7 +1170,14 @@
{
if (__ht._M_node_allocator() == this->_M_node_allocator())
{
- _M_buckets = __ht._M_buckets;
+ if (__builtin_expect(__ht._M_buckets == &__ht._M_single_bucket, false))
+ {
+ _M_buckets = &_M_single_bucket;
+ _M_single_bucket = __ht._M_single_bucket;
+ }
+ else
+ _M_buckets = __ht._M_buckets;
+
_M_before_begin._M_nxt = __ht._M_before_begin._M_nxt;
// Update, if necessary, bucket pointing to before begin that hasn't
// moved.
@@ -1193,11 +1231,21 @@
std::swap(_M_bucket_count, __x._M_bucket_count);
std::swap(_M_before_begin._M_nxt, __x._M_before_begin._M_nxt);
std::swap(_M_element_count, __x._M_element_count);
+ std::swap(_M_single_bucket, __x._M_single_bucket);
+ // Fix buckets if any is pointing to its single bucket that can't be
+ // swapped.
+ if (_M_buckets == &__x._M_single_bucket)
+ _M_buckets = &_M_single_bucket;
+
+ if (__x._M_buckets == &_M_single_bucket)
+ __x._M_buckets = &__x._M_single_bucket;
+
// Fix buckets containing the _M_before_begin pointers that can't be
// swapped.
if (_M_begin())
_M_buckets[_M_bucket_index(_M_begin())] = &_M_before_begin;
+
if (__x._M_begin())
__x._M_buckets[__x._M_bucket_index(__x._M_begin())]
= &__x._M_before_begin;
@@ -1230,9 +1278,6 @@
_H1, _H2, _Hash, _RehashPolicy, _Traits>::
find(const key_type& __k)
{
- if (__builtin_expect(_M_bucket_count == 0, false))
- return end();
-
__hash_code __code = this->_M_hash_code(__k);
std::size_t __n = _M_bucket_index(__k, __code);
__node_type* __p = _M_find_node(__n, __k, __code);
@@ -1250,9 +1295,6 @@
_H1, _H2, _Hash, _RehashPolicy, _Traits>::
find(const key_type& __k) const
{
- if (__builtin_expect(_M_bucket_count == 0, false))
- return end();
-
__hash_code __code = this->_M_hash_code(__k);
std::size_t __n = _M_bucket_index(__k, __code);
__node_type* __p = _M_find_node(__n, __k, __code);
@@ -1270,9 +1312,6 @@
_H1, _H2, _Hash, _RehashPolicy, _Traits>::
count(const key_type& __k) const
{
- if (__builtin_expect(_M_bucket_count == 0, false))
- return 0;
-
__hash_code __code = this->_M_hash_code(__k);
std::size_t __n = _M_bucket_index(__k, __code);
__node_type* __p = _M_bucket_begin(__n);
@@ -1311,9 +1350,6 @@
_H1, _H2, _Hash, _RehashPolicy, _Traits>::
equal_range(const key_type& __k)
{
- if (__builtin_expect(_M_bucket_count == 0, false))
- return std::make_pair(end(), end());
-
__hash_code __code = this->_M_hash_code(__k);
std::size_t __n = _M_bucket_index(__k, __code);
__node_type* __p = _M_find_node(__n, __k, __code);
@@ -1347,9 +1383,6 @@
_H1, _H2, _Hash, _RehashPolicy, _Traits>::
equal_range(const key_type& __k) const
{
- if (__builtin_expect(_M_bucket_count == 0, false))
- return std::make_pair(end(), end());
-
__hash_code __code = this->_M_hash_code(__k);
std::size_t __n = _M_bucket_index(__k, __code);
__node_type* __p = _M_find_node(__n, __k, __code);
@@ -1944,7 +1977,7 @@
_H1, _H2, _Hash, _RehashPolicy, _Traits>::
_M_rehash_aux(size_type __n, std::true_type)
{
- __bucket_type* __new_buckets = this->_M_allocate_buckets(__n);
+ __bucket_type* __new_buckets = _M_allocate_buckets(__n);
__node_type* __p = _M_begin();
_M_before_begin._M_nxt = nullptr;
std::size_t __bbegin_bkt = 0;
@@ -1969,8 +2002,7 @@
__p = __next;
}
- if (__builtin_expect(_M_bucket_count != 0, true))
- _M_deallocate_buckets();
+ _M_deallocate_buckets();
_M_bucket_count = __n;
_M_buckets = __new_buckets;
}
@@ -1986,7 +2018,7 @@
_H1, _H2, _Hash, _RehashPolicy, _Traits>::
_M_rehash_aux(size_type __n, std::false_type)
{
- __bucket_type* __new_buckets = this->_M_allocate_buckets(__n);
+ __bucket_type* __new_buckets = _M_allocate_buckets(__n);
__node_type* __p = _M_begin();
_M_before_begin._M_nxt = nullptr;
@@ -2060,8 +2092,7 @@
__new_buckets[__next_bkt] = __prev_p;
}
- if (__builtin_expect(_M_bucket_count != 0, true))
- _M_deallocate_buckets();
+ _M_deallocate_buckets();
_M_bucket_count = __n;
_M_buckets = __new_buckets;
}
Index: testsuite/23_containers/unordered_map/allocator/copy_assign.cc
===================================================================
--- testsuite/23_containers/unordered_map/allocator/copy_assign.cc (revision 210479)
+++ testsuite/23_containers/unordered_map/allocator/copy_assign.cc (working copy)
@@ -17,6 +17,7 @@
// { dg-options "-std=c++11" }
+#include <iostream>
#include <unordered_map>
#include <testsuite_hooks.h>
#include <testsuite_allocator.h>
@@ -56,22 +57,37 @@
void test02()
{
bool test __attribute__((unused)) = true;
- typedef propagating_allocator<T, true> alloc_type;
- typedef std::unordered_map<T, T, hash, equal_to, alloc_type> test_type;
- test_type v1(alloc_type(1));
- v1.emplace(std::piecewise_construct,
- std::make_tuple(T()), std::make_tuple(T()));
- test_type v2(alloc_type(2));
- v2.emplace(std::piecewise_construct,
- std::make_tuple(T()), std::make_tuple(T()));
- v2 = v1;
- VERIFY(1 == v1.get_allocator().get_personality());
- VERIFY(1 == v2.get_allocator().get_personality());
+ {
+ typedef propagating_allocator<T, true> alloc_type;
+ typedef std::unordered_map<T, T, hash, equal_to, alloc_type> test_type;
+ std::cout << "Instantiate v1" << std::endl;
+ test_type v1(alloc_type(1));
+ std::cout << "Emplace in v1" << std::endl;
+ v1.emplace(std::piecewise_construct,
+ std::make_tuple(T()), std::make_tuple(T()));
+ {
+ std::cout << "Instantiate v2" << std::endl;
+ test_type v2(alloc_type(2));
+ std::cout << "Emplace in v2" << std::endl;
+ v2.emplace(std::piecewise_construct,
+ std::make_tuple(T()), std::make_tuple(T()));
+ std::cout << "v2 = v1" << std::endl;
+ v2 = v1;
+ std::cout << "Done" << std::endl;
+ VERIFY(1 == v1.get_allocator().get_personality());
+ VERIFY(1 == v2.get_allocator().get_personality());
+ }
+ std::cout << "v2 destroyed" << std::endl;
+ }
+ std::cout << "v1 destroyed" << std::endl;
}
int main()
{
+ std::cout << "Running test01" << std::endl;
test01();
+ std::cout << "Running test02" << std::endl;
test02();
+ std::cout << "Done" << std::endl;
return 0;
}
Index: testsuite/23_containers/unordered_set/61143.cc
===================================================================
--- testsuite/23_containers/unordered_set/61143.cc (revision 0)
+++ testsuite/23_containers/unordered_set/61143.cc (working copy)
@@ -0,0 +1,38 @@
+// { dg-options "-std=gnu++11" }
+
+// Copyright (C) 2014 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library. This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3. If not see
+// <http://www.gnu.org/licenses/>.
+
+// libstdc++/61143
+
+#include <unordered_set>
+
+void test01()
+{
+ std::unordered_set<int> us1, us2;
+ us1.insert(1);
+
+ us2 = std::move(us1);
+
+ us1.insert(1);
+}
+
+int main()
+{
+ test01();
+ return 0;
+}
Index: testsuite/Makefile.in
===================================================================
--- testsuite/Makefile.in (revision 210479)
+++ testsuite/Makefile.in (working copy)
@@ -1,9 +1,9 @@
-# Makefile.in generated by automake 1.11.1 from Makefile.am.
+# Makefile.in generated by automake 1.11.6 from Makefile.am.
# @configure_input@
# Copyright (C) 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002,
-# 2003, 2004, 2005, 2006, 2007, 2008, 2009 Free Software Foundation,
-# Inc.
+# 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Free Software
+# Foundation, Inc.
# This Makefile.in is free software; the Free Software Foundation
# gives unlimited permission to copy and/or distribute it,
# with or without modifications, as long as this notice is preserved.
@@ -15,6 +15,23 @@
@SET_MAKE@
VPATH = @srcdir@
+am__make_dryrun = \
+ { \
+ am__dry=no; \
+ case $$MAKEFLAGS in \
+ *\\[\ \ ]*) \
+ echo 'am--echo: ; @echo "AM" OK' | $(MAKE) -f - 2>/dev/null \
+ | grep '^AM OK$$' >/dev/null || am__dry=yes;; \
+ *) \
+ for am__flg in $$MAKEFLAGS; do \
+ case $$am__flg in \
+ *=*|--*) ;; \
+ *n*) am__dry=yes; break;; \
+ esac; \
+ done;; \
+ esac; \
+ test $$am__dry = yes; \
+ }
pkgdatadir = $(datadir)/@PACKAGE@
pkgincludedir = $(includedir)/@PACKAGE@
pkglibdir = $(libdir)/@PACKAGE@
@@ -67,6 +84,11 @@
depcomp =
am__depfiles_maybe =
SOURCES =
+am__can_run_installinfo = \
+ case $$AM_UPDATE_INFO_DIR in \
+ n|no|NO) false;; \
+ *) (install-info --version) >/dev/null 2>&1;; \
+ esac
ABI_TWEAKS_SRCDIR = @ABI_TWEAKS_SRCDIR@
ACLOCAL = @ACLOCAL@
ALLOCATOR_H = @ALLOCATOR_H@
@@ -360,6 +382,7 @@
echo ' cd $(top_builddir) && $(SHELL) ./config.status $(subdir)/$@ $(am__depfiles_maybe)'; \
cd $(top_builddir) && $(SHELL) ./config.status $(subdir)/$@ $(am__depfiles_maybe);; \
esac;
+$(top_srcdir)/fragment.am:
$(top_builddir)/config.status: $(top_srcdir)/configure $(CONFIG_STATUS_DEPENDENCIES)
cd $(top_builddir) && $(MAKE) $(AM_MAKEFLAGS) am--refresh
@@ -395,10 +418,15 @@
installcheck: installcheck-am
install-strip:
- $(MAKE) $(AM_MAKEFLAGS) INSTALL_PROGRAM="$(INSTALL_STRIP_PROGRAM)" \
- install_sh_PROGRAM="$(INSTALL_STRIP_PROGRAM)" INSTALL_STRIP_FLAG=-s \
- `test -z '$(STRIP)' || \
- echo "INSTALL_PROGRAM_ENV=STRIPPROG='$(STRIP)'"` install
+ if test -z '$(STRIP)'; then \
+ $(MAKE) $(AM_MAKEFLAGS) INSTALL_PROGRAM="$(INSTALL_STRIP_PROGRAM)" \
+ install_sh_PROGRAM="$(INSTALL_STRIP_PROGRAM)" INSTALL_STRIP_FLAG=-s \
+ install; \
+ else \
+ $(MAKE) $(AM_MAKEFLAGS) INSTALL_PROGRAM="$(INSTALL_STRIP_PROGRAM)" \
+ install_sh_PROGRAM="$(INSTALL_STRIP_PROGRAM)" INSTALL_STRIP_FLAG=-s \
+ "INSTALL_PROGRAM_ENV=STRIPPROG='$(STRIP)'" install; \
+ fi
mostlyclean-generic:
clean-generic: