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[PATCH] Fix regex_iterator end() state and operator==()
- From: Tim Shen <timshen at google dot com>
- To: "libstdc++" <libstdc++ at gcc dot gnu dot org>, gcc-patches <gcc-patches at gcc dot gnu dot org>
- Date: Mon, 7 Nov 2016 23:01:17 -0800
- Subject: [PATCH] Fix regex_iterator end() state and operator==()
- Authentication-results: sourceware.org; auth=none
This fixes libstdc++/78236. I'm surprised that this bug was not
revealed until now :P.
Bootstrapped and tested under x86_64-linux-gnu.
I'm happy with however many backports.
--
Regards,
Tim Shen
commit 8aee66b743b5b0ef09cbc9587ebbacf6665ba0cb
Author: Tim Shen <timshen@google.com>
Date: Mon Nov 7 21:50:49 2016 -0800
* libstdc++-v3/include/bits/regex.h (regex_iterator::regex_iterator()):
Define end() as _M_pregex == nullptr.
* libstdc++-v3/include/bits/regex.tcc (regex_iterator::operator==(),
regex_iterator::operator++()): Fix operator==() and operator++() to
look at null-ness of _M_pregex on both sides.
* testsuite/28_regex/regression.cc: New testcase.
diff --git a/libstdc++-v3/include/bits/regex.h b/libstdc++-v3/include/bits/regex.h
index a7d45e6..aadf312 100644
--- a/libstdc++-v3/include/bits/regex.h
+++ b/libstdc++-v3/include/bits/regex.h
@@ -2454,7 +2454,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
* one-past-the-end of a range.
*/
regex_iterator()
- : _M_match()
+ : _M_pregex()
{ }
/**
diff --git a/libstdc++-v3/include/bits/regex.tcc b/libstdc++-v3/include/bits/regex.tcc
index 4a3d7c3..3f8969d 100644
--- a/libstdc++-v3/include/bits/regex.tcc
+++ b/libstdc++-v3/include/bits/regex.tcc
@@ -496,12 +496,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
regex_iterator<_Bi_iter, _Ch_type, _Rx_traits>::
operator==(const regex_iterator& __rhs) const
{
- return (_M_match.empty() && __rhs._M_match.empty())
- || (_M_begin == __rhs._M_begin
- && _M_end == __rhs._M_end
- && _M_pregex == __rhs._M_pregex
- && _M_flags == __rhs._M_flags
- && _M_match[0] == __rhs._M_match[0]);
+ if (_M_pregex == nullptr && __rhs._M_pregex == nullptr)
+ return true;
+ return _M_pregex == __rhs._M_pregex
+ && _M_begin == __rhs._M_begin
+ && _M_end == __rhs._M_end
+ && _M_flags == __rhs._M_flags
+ && _M_match[0] == __rhs._M_match[0];
}
template<typename _Bi_iter,
@@ -525,7 +526,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{
if (__start == _M_end)
{
- _M_match = value_type();
+ _M_pregex = nullptr;
return *this;
}
else
@@ -558,7 +559,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_M_match._M_begin = _M_begin;
}
else
- _M_match = value_type();
+ _M_pregex = nullptr;
}
return *this;
}
diff --git a/libstdc++-v3/testsuite/28_regex/regression.cc b/libstdc++-v3/testsuite/28_regex/regression.cc
index effb356..5214fe3 100644
--- a/libstdc++-v3/testsuite/28_regex/regression.cc
+++ b/libstdc++-v3/testsuite/28_regex/regression.cc
@@ -72,6 +72,27 @@ test05()
VERIFY(regex_match_debug("-", std::regex("[a-]")));
}
+// PR libstdc++/78236
+void
+test06()
+{
+ char const s[] = "afoo";
+ std::basic_regex<char> r("(f+)");
+ {
+ std::cregex_iterator i(s, s+sizeof(s), r);
+ std::cregex_iterator j(s, s+sizeof(s), r);
+ VERIFY(i == j);
+ }
+ // The iterator manipulation code must be repeated in the same scope
+ // to expose the undefined read during the execution of the ==
+ // operator (stack location reuse)
+ {
+ std::cregex_iterator i(s, s+sizeof(s), r);
+ std::cregex_iterator j;
+ VERIFY(!(i == j));
+ }
+}
+
int
main()
{
@@ -80,6 +101,7 @@ main()
test03();
test04();
test05();
+ test06();
return 0;
}