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re PR libstdc++/66017 (Undefined behaviour in std::set<long long>)

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PR libstdc++/66017
	* include/bits/stl_tree.h (_Rb_tree_node): Use __aligned_membuf.
	(_Rb_tree_iterator, _Rb_tree_const_iterator): Support construction
	from _Base_ptr.
	(_Rb_tree_const_iterator::_M_const_cast): Remove static_cast.
	(_Rb_tree::begin, _Rb_tree::end): Remove static_cast.
	* include/ext/aligned_buffer.h (__aligned_membuf): New type using
	alignment of _Tp as a member subobject, not as a complete object.
	* python/libstdcxx/v6/printers.py (StdRbtreeIteratorPrinter): Lookup
	_Link_type manually as it might not be in the debug info.

From-SVN: r223745
This commit is contained in:
Jonathan Wakely 2015-05-27 12:18:37 +01:00 • committed by Jonathan Wakely
parent b1af7da612
commit 2097b5b029
4 changed files with 66 additions and 21 deletions
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13
libstdc++-v3/ChangeLog
View file

@ -1,3 +1,16 @@
2015-05-27 Jonathan Wakely <jwakely@redhat.com>
PR libstdc++/66017
* include/bits/stl_tree.h (_Rb_tree_node): Use __aligned_membuf.
(_Rb_tree_iterator, _Rb_tree_const_iterator): Support construction
from _Base_ptr.
(_Rb_tree_const_iterator::_M_const_cast): Remove static_cast.
(_Rb_tree::begin, _Rb_tree::end): Remove static_cast.
* include/ext/aligned_buffer.h (__aligned_membuf): New type using
alignment of _Tp as a member subobject, not as a complete object.
* python/libstdcxx/v6/printers.py (StdRbtreeIteratorPrinter): Lookup
_Link_type manually as it might not be in the debug info.
2015-05-26 Doug Evans <dje@google.com>
* python/libstdcxx/v6/xmethods.py (UniquePtrMethodsMatcher): Add

26
libstdc++-v3/include/bits/stl_tree.h
View file

@ -146,7 +146,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_M_valptr() const
{ return std::__addressof(_M_value_field); }
#else
__gnu_cxx::__aligned_buffer<_Val> _M_storage;
__gnu_cxx::__aligned_membuf<_Val> _M_storage;
_Val*
_M_valptr()
@ -188,7 +188,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
: _M_node() { }
explicit
_Rb_tree_iterator(_Link_type __x) _GLIBCXX_NOEXCEPT
_Rb_tree_iterator(_Base_ptr __x) _GLIBCXX_NOEXCEPT
: _M_node(__x) { }
reference
@ -260,7 +260,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
: _M_node() { }
explicit
_Rb_tree_const_iterator(_Link_type __x) _GLIBCXX_NOEXCEPT
_Rb_tree_const_iterator(_Base_ptr __x) _GLIBCXX_NOEXCEPT
: _M_node(__x) { }
_Rb_tree_const_iterator(const iterator& __it) _GLIBCXX_NOEXCEPT
@ -268,8 +268,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
iterator
_M_const_cast() const _GLIBCXX_NOEXCEPT
{ return iterator(static_cast<typename iterator::_Link_type>
(const_cast<typename iterator::_Base_ptr>(_M_node))); }
{ return iterator(const_cast<typename iterator::_Base_ptr>(_M_node)); }
reference
operator*() const _GLIBCXX_NOEXCEPT
@ -868,28 +867,19 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
iterator
begin() _GLIBCXX_NOEXCEPT
{
return iterator(static_cast<_Link_type>
(this->_M_impl._M_header._M_left));
}
{ return iterator(this->_M_impl._M_header._M_left); }
const_iterator
begin() const _GLIBCXX_NOEXCEPT
{
return const_iterator(static_cast<_Const_Link_type>
(this->_M_impl._M_header._M_left));
}
{ return const_iterator(this->_M_impl._M_header._M_left); }
iterator
end() _GLIBCXX_NOEXCEPT
{ return iterator(static_cast<_Link_type>(&this->_M_impl._M_header)); }
{ return iterator(&this->_M_impl._M_header); }
const_iterator
end() const _GLIBCXX_NOEXCEPT
{
return const_iterator(static_cast<_Const_Link_type>
(&this->_M_impl._M_header));
}
{ return const_iterator(&this->_M_impl._M_header); }
reverse_iterator
rbegin() _GLIBCXX_NOEXCEPT

41
libstdc++-v3/include/ext/aligned_buffer.h
View file

@ -39,6 +39,47 @@
namespace __gnu_cxx
{
// A utility type containing a POD object that can hold an object of type
// _Tp initialized via placement new or allocator_traits::construct.
// Intended for use as a data member subobject, use __aligned_buffer for
// complete objects.
template<typename _Tp>
struct __aligned_membuf
{
// Target macro ADJUST_FIELD_ALIGN can produce different alignment for
// types when used as class members. __aligned_membuf is intended
// for use as a class member, so align the buffer as for a class member.
struct _Tp2 { _Tp _M_t; };
alignas(__alignof__(_Tp2::_M_t)) unsigned char _M_storage[sizeof(_Tp)];
__aligned_membuf() = default;
// Can be used to avoid value-initialization zeroing _M_storage.
__aligned_membuf(std::nullptr_t) { }
void*
_M_addr() noexcept
{ return static_cast<void*>(&_M_storage); }
const void*
_M_addr() const noexcept
{ return static_cast<const void*>(&_M_storage); }
_Tp*
_M_ptr() noexcept
{ return static_cast<_Tp*>(_M_addr()); }
const _Tp*
_M_ptr() const noexcept
{ return static_cast<const _Tp*>(_M_addr()); }
};
// Similar to __aligned_membuf but aligned for complete objects, not members.
// This type is used in <forward_list>, <future>, <bits/shared_ptr_base.h>
// and <bits/hashtable_policy.h>, but ideally they would use __aligned_membuf
// instead, as it has smaller size for some types on some targets.
// This type is still used to avoid an ABI change.
template<typename _Tp>
struct __aligned_buffer
: std::aligned_storage<sizeof(_Tp), std::alignment_of<_Tp>::value>

7
libstdc++-v3/python/libstdcxx/v6/printers.py
View file

@ -456,11 +456,12 @@ class StdRbtreeIteratorPrinter:
def __init__ (self, typename, val):
self.val = val
valtype = self.val.type.template_argument(0).strip_typedefs()
nodetype = gdb.lookup_type('std::_Rb_tree_node<' + str(valtype) + '>')
self.link_type = nodetype.strip_typedefs().pointer()
def to_string (self):
typename = str(self.val.type.strip_typedefs()) + '::_Link_type'
nodetype = gdb.lookup_type(typename).strip_typedefs()
node = self.val.cast(nodetype).dereference()
node = self.val['_M_node'].cast(self.link_type).dereference()
return get_value_from_Rb_tree_node(node)
class StdDebugIteratorPrinter: