On 16/05/19 11:05 +0100, Jonathan Wakely wrote:
On 16/05/19 07:47 +0200, François Dumont wrote:
On 5/15/19 5:37 PM, Jonathan Wakely wrote:
François,
I noticed that _Hash_code_base and _Hashtable_base have a number of
member functions which are overloaded for const and non-const:
const _Equal&
_M_eq() const { return _EqualEBO::_S_cget(*this); }
_Equal&
_M_eq() { return _EqualEBO::_S_get(*this); }
The non-const ones seem to be unnecessary. They're used in the _M_swap
member functions, but all other uses could (and probably should) call
the const overload to get a const reference to the function object.
If we make the _M_swap members use the EBO accessors directly then we
can get rid of the non-const accessors. That makes overload resolution
simpler for the compiler (as there's only one function to choose from)
and should result in slightly smaller code when inlining is not
enabled.
Do you see any problem with this patch?
I think it is more a Pavlov behavior, always providing const and
non-const no matter what.
No problem to simplify this.
OK, tested powerpc64le-linux, committed to trunk.
I don't see a need for the _Hashtable_ebo_helper member functions to
be static. They return a member of *this, but are static so *this has
to be passed as a parameter. We could just make them non-static.
It seems to have always been that way since the first version of the
patch that added the helpers:
https://gcc.gnu.org/ml/libstdc++/2011-12/msg00139.html
This patch passes all tests. I plan to commit this to trunk too.
commit 73b18aaa3a42f446b3bf295ef5bcd2e3af45004f
Author: Jonathan Wakely <jwak...@redhat.com>
Date: Thu May 16 13:01:34 2019 +0100
Change EBO accessors from static to non-static member functions
* include/bits/hashtable_policy.h (_Hashtable_ebo_helper::_S_get):
Replace with _M_get non-static member function.
(_Hashtable_ebo_helper::_S_cget): Replace with _M_cget non-static
member function.
(_Hash_code_base, _Local_iterator_base, _Hashtable_base):
(_Hashtable_alloc): Adjust to use non-static members of EBO helper.
diff --git a/libstdc++-v3/include/bits/hashtable_policy.h b/libstdc++-v3/include/bits/hashtable_policy.h
index b417a7d442c..f7db7628c69 100644
--- a/libstdc++-v3/include/bits/hashtable_policy.h
+++ b/libstdc++-v3/include/bits/hashtable_policy.h
@@ -1112,13 +1112,8 @@ namespace __detail
: _Tp(std::forward<_OtherTp>(__tp))
{ }
- static const _Tp&
- _S_cget(const _Hashtable_ebo_helper& __eboh)
- { return static_cast<const _Tp&>(__eboh); }
-
- static _Tp&
- _S_get(_Hashtable_ebo_helper& __eboh)
- { return static_cast<_Tp&>(__eboh); }
+ const _Tp& _M_cget() const { return static_cast<const _Tp&>(*this); }
+ _Tp& _M_get() { return static_cast<_Tp&>(*this); }
};
/// Specialization not using EBO.
@@ -1132,13 +1127,8 @@ namespace __detail
: _M_tp(std::forward<_OtherTp>(__tp))
{ }
- static const _Tp&
- _S_cget(const _Hashtable_ebo_helper& __eboh)
- { return __eboh._M_tp; }
-
- static _Tp&
- _S_get(_Hashtable_ebo_helper& __eboh)
- { return __eboh._M_tp; }
+ const _Tp& _M_cget() const { return _M_tp; }
+ _Tp& _M_get() { return _M_tp; }
private:
_Tp _M_tp;
@@ -1229,16 +1219,16 @@ namespace __detail
void
_M_swap(_Hash_code_base& __x)
{
- std::swap(__ebo_extract_key::_S_get(*this),
- __ebo_extract_key::_S_get(__x));
- std::swap(__ebo_hash::_S_get(*this), __ebo_hash::_S_get(__x));
+ std::swap(__ebo_extract_key::_M_get(),
+ __x.__ebo_extract_key::_M_get());
+ std::swap(__ebo_hash::_M_get(), __x.__ebo_hash::_M_get());
}
const _ExtractKey&
- _M_extract() const { return __ebo_extract_key::_S_cget(*this); }
+ _M_extract() const { return __ebo_extract_key::_M_cget(); }
const _Hash&
- _M_ranged_hash() const { return __ebo_hash::_S_cget(*this); }
+ _M_ranged_hash() const { return __ebo_hash::_M_cget(); }
};
// No specialization for ranged hash function while caching hash codes.
@@ -1317,20 +1307,20 @@ namespace __detail
void
_M_swap(_Hash_code_base& __x)
{
- std::swap(__ebo_extract_key::_S_get(*this),
- __ebo_extract_key::_S_get(__x));
- std::swap(__ebo_h1::_S_get(*this), __ebo_h1::_S_get(__x));
- std::swap(__ebo_h2::_S_get(*this), __ebo_h2::_S_get(__x));
+ std::swap(__ebo_extract_key::_M_get(),
+ __x.__ebo_extract_key::_M_get());
+ std::swap(__ebo_h1::_M_get(), __x.__ebo_h1::_M_get());
+ std::swap(__ebo_h2::_M_get(), __x.__ebo_h2::_M_get());
}
const _ExtractKey&
- _M_extract() const { return __ebo_extract_key::_S_cget(*this); }
+ _M_extract() const { return __ebo_extract_key::_M_cget(); }
const _H1&
- _M_h1() const { return __ebo_h1::_S_cget(*this); }
+ _M_h1() const { return __ebo_h1::_M_cget(); }
const _H2&
- _M_h2() const { return __ebo_h2::_S_cget(*this); }
+ _M_h2() const { return __ebo_h2::_M_cget(); }
};
/// Specialization: hash function and range-hashing function,
@@ -1397,20 +1387,20 @@ namespace __detail
void
_M_swap(_Hash_code_base& __x)
{
- std::swap(__ebo_extract_key::_S_get(*this),
- __ebo_extract_key::_S_get(__x));
- std::swap(__ebo_h1::_S_get(*this), __ebo_h1::_S_get(__x));
- std::swap(__ebo_h2::_S_get(*this), __ebo_h2::_S_get(__x));
+ std::swap(__ebo_extract_key::_M_get(),
+ __x.__ebo_extract_key::_M_get());
+ std::swap(__ebo_h1::_M_get(), __x.__ebo_h1::_M_get());
+ std::swap(__ebo_h2::_M_get(), __x.__ebo_h2::_M_get());
}
const _ExtractKey&
- _M_extract() const { return __ebo_extract_key::_S_cget(*this); }
+ _M_extract() const { return __ebo_extract_key::_M_cget(); }
const _H1&
- _M_h1() const { return __ebo_h1::_S_cget(*this); }
+ _M_h1() const { return __ebo_h1::_M_cget(); }
const _H2&
- _M_h2() const { return __ebo_h2::_S_cget(*this); }
+ _M_h2() const { return __ebo_h2::_M_cget(); }
};
/**
@@ -1471,7 +1461,7 @@ namespace __detail
if (_M_cur)
{
std::size_t __bkt
- = __base_type::_S_get(*this)(_M_cur->_M_hash_code,
+ = __base_type::_M_get()(_M_cur->_M_hash_code,
_M_bucket_count);
if (__bkt != _M_bucket)
_M_cur = nullptr;
@@ -1819,11 +1809,11 @@ namespace __detail
_M_swap(_Hashtable_base& __x)
{
__hash_code_base::_M_swap(__x);
- std::swap(_EqualEBO::_S_get(*this), _EqualEBO::_S_get(__x));
+ std::swap(_EqualEBO::_M_get(), __x._EqualEBO::_M_get());
}
const _Equal&
- _M_eq() const { return _EqualEBO::_S_cget(*this); }
+ _M_eq() const { return _EqualEBO::_M_cget(); }
};
/**
@@ -2021,11 +2011,11 @@ namespace __detail
__node_alloc_type&
_M_node_allocator()
- { return __ebo_node_alloc::_S_get(*this); }
+ { return __ebo_node_alloc::_M_get(); }
const __node_alloc_type&
_M_node_allocator() const
- { return __ebo_node_alloc::_S_cget(*this); }
+ { return __ebo_node_alloc::_M_cget(); }
template<typename... _Args>
__node_type*
