OpenE2K
/
gcc
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Reduce code instantiated by filesystem::path::_S_convert_loc 

Jakub noted in https://gcc.gnu.org/ml/libstdc++/2019-04/msg00140.html
that an unwanted std::wstring::_M_replace_dispatch symbol has started to
be exported from the Fedora shared library. This symbol is triggered by
the instantiation of std::wstring::assign(const char*, const char*) from
std::__str_codecvt_in which is called from path::_S_convert_loc. The
branch that triggers that instantiation can't actually happen in that
case, because codecvt facets will only return noconv when the input and
output types are the same. Guarding the assign call with an if-constexpr
check that the types are the same avoids instantiating template
specializations that will never actually be needed.

	* config/abi/pre/gnu.ver (GLIBCXX_3.4): Replace wildcard that matches
	wstring::_M_replace_dispatch with more specific patterns.
	* include/bits/fs_path.h (path::_S_convert_loc<_InputIterator>):
	Create const std::string to avoid redundant call to _S_convert_loc
	with non-const pointers.
	* include/bits/locale_conv.h (__do_str_codecvt): Use if-constexpr to
	avoid unnecessary basic_string::assign instantiations.

From-SVN: r270602
This commit is contained in:
Jonathan Wakely 2019-04-26 15:04:45 +01:00 committed by Jonathan Wakely
parent 3addb7b937
commit 8281e3b8ea
4 changed files with 19 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
libstdc++-v3/ChangeLog
View File

@ -1,5 +1,13 @@
2019-04-26 Jonathan Wakely <jwakely@redhat.com>
* config/abi/pre/gnu.ver (GLIBCXX_3.4): Replace wildcard that matches
wstring::_M_replace_dispatch with more specific patterns.
* include/bits/fs_path.h (path::_S_convert_loc<_InputIterator>):
Create const std::string to avoid redundant call to _S_convert_loc
with non-const pointers.
* include/bits/locale_conv.h (__do_str_codecvt): Use if-constexpr to
avoid unnecessary basic_string::assign instantiations.
* include/std/memory (__uses_alloc_args): Add string-literal to
static_assert, to match the one in __uses_alloc.
[__cpp_concepts] (_Std_pair): Use C++2a syntax for concept.

3
libstdc++-v3/config/abi/pre/gnu.ver
View File

@ -299,7 +299,8 @@ GLIBCXX_3.4 {
_ZNSbIwSt11char_traitsIwESaIwEE12_S_constructE[jmy]wRKS1_;
_ZNSbIwSt11char_traitsIwESaIwEE12_S_empty_repEv;
_ZNSbIwSt11char_traitsIwESaIwEE13_S_copy_chars*;
_ZNSbIwSt11char_traitsIwESaIwEE[0-9][0-9]_M_replace*;
_ZNSbIwSt11char_traitsIwESaIwEE14_M_replace_aux*;
_ZNSbIwSt11char_traitsIwESaIwEE15_M_replace_safe*;
_ZNSbIwSt11char_traitsIwESaIwEE4_Rep10_M_destroy*;
_ZNSbIwSt11char_traitsIwESaIwEE4_Rep10_M_dispose*;
_ZNSbIwSt11char_traitsIwESaIwEE4_Rep10_M_refcopyEv;

2
libstdc++-v3/include/bits/fs_path.h
View File

@ -539,7 +539,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
_S_convert_loc(_InputIterator __src, __null_terminated,
const std::locale& __loc)
{
std::string __s = _S_string_from_iter(__src);
const std::string __s = _S_string_from_iter(__src);
return _S_convert_loc(__s.data(), __s.data() + __s.size(), __loc);
}

10
libstdc++-v3/include/bits/locale_conv.h
View File

@ -88,8 +88,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
if (__result == codecvt_base::noconv)
{
__outstr.assign(__first, __last);
__count = __last - __first;
// The codecvt facet will only return noconv when the types are
// the same, so avoid instantiating basic_string::assign otherwise
if _GLIBCXX17_CONSTEXPR (is_same<typename _Codecvt::intern_type,
typename _Codecvt::extern_type>())
{
__outstr.assign(__first, __last);
__count = __last - __first;
}
}
else
{