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libstdc++: Remove <memory_resource> dependency from <regex> [PR 92546]

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Unlike the other headers that declare alias templates in namespace pmr,
<regex> includes <memory_resource>. That was done because the
pmr::string::const_iterator typedef requires pmr::string to be complete,
which requires pmr::polymorphic_allocator<char> to be complete.

By using __normal_iterator<const char*, pmr::string> instead of the
const_iterator typedef we can avoid the completeness requirement.

This makes <regex> smaller, by not requiring <memory_resource> and its
<shared_mutex> dependency, which depends on <chrono>.  Backporting this
will also help with PR 97876, where <stop_token> ends up being needed by
<regex> via <memory_resource>.

libstdc++-v3/ChangeLog:

	PR libstdc++/92546
	* include/std/regex (pmr::smatch, pmr::wsmatch): Declare using
	underlying __normal_iterator type, not nested typedef
	basic_string::const_iterator.
This commit is contained in:
Jonathan Wakely 2020-11-20 11:30:33 +00:00
parent 4405edb496
commit 640ebeb336
1 changed files with 9 additions and 5 deletions
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14
libstdc++-v3/include/std/regex
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@ -64,21 +64,25 @@
#include <bits/regex_executor.h>
#if __cplusplus >= 201703L && _GLIBCXX_USE_CXX11_ABI
#include <memory_resource>
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
namespace pmr {
namespace pmr
{
template<typename _Tp> class polymorphic_allocator;
template<typename _BidirectionalIterator>
using match_results
= std::match_results<_BidirectionalIterator, polymorphic_allocator<
sub_match<_BidirectionalIterator>>>;
using cmatch = match_results<const char*>;
using smatch = match_results<string::const_iterator>;
using cmatch = match_results<const char*>;
// Use __normal_iterator directly, because pmr::string::const_iterator
// would require pmr::polymorphic_allocator to be complete.
using smatch
= match_results<__gnu_cxx::__normal_iterator<const char*, string>>;
#ifdef _GLIBCXX_USE_WCHAR_T
using wcmatch = match_results<const wchar_t*>;
using wsmatch = match_results<wstring::const_iterator>;
using wsmatch
= match_results<__gnu_cxx::__normal_iterator<const wchar_t*, wstring>>;
#endif
} // namespace pmr
_GLIBCXX_END_NAMESPACE_VERSION