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re PR libstdc++/61424 (std::regex matches right to left, not leftmost longest)

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PR libstdc++/61424
	* include/bits/regex.tcc (__regex_algo_impl<>): Use DFS for ECMAScript,
	not just regex containing back-references.
	* include/bits/regex_compiler.tcc (_Compiler<>::_M_disjunction):
	exchange _M_next and _M_alt for alternative operator,
	making matching from left to right.
	* include/bits/regex_executor.h (_State_info<>::_M_get_sol_pos):
	Add position tracking fom DFS.
	* include/bits/regex_executor.tcc (_Executor<>::_M_main_dispatch,
	_Executor<>::_M_dfs): Likewise.
	* include/bits/regex_scanner.h: Remove unused enum entry.
	* testsuite/28_regex/algorithms/regex_search/61424.cc: New
	testcase from PR.

From-SVN: r212184
This commit is contained in:
Tim Shen 2014-07-01 02:10:31 +00:00 committed by Tim Shen
parent 25f28ff0ea
commit ad9ec7b3c5
7 changed files with 123 additions and 8 deletions
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16
libstdc++-v3/ChangeLog
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@ -1,3 +1,19 @@
2014-07-01 Tim Shen <timshen@google.com>
PR libstdc++/61424
* include/bits/regex.tcc (__regex_algo_impl<>): Use DFS for ECMAScript,
not just regex containing back-references.
* include/bits/regex_compiler.tcc (_Compiler<>::_M_disjunction):
exchange _M_next and _M_alt for alternative operator,
making matching from left to right.
* include/bits/regex_executor.h (_State_info<>::_M_get_sol_pos):
Add position tracking fom DFS.
* include/bits/regex_executor.tcc (_Executor<>::_M_main_dispatch,
_Executor<>::_M_dfs): Likewise.
* include/bits/regex_scanner.h: Remove unused enum entry.
* testsuite/28_regex/algorithms/regex_search/61424.cc: New
testcase from PR.
2014-06-30 Jason Merrill <jason@redhat.com>
* libsupc++/cxxabi.h (class __pbase_type_info): __pointer_catch

1
libstdc++-v3/include/bits/regex.tcc
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@ -71,6 +71,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// _GLIBCXX_REGEX_USE_THOMPSON_NFA if they need to use this approach.
bool __ret;
if (!__re._M_automaton->_M_has_backref
&& !(__re._M_flags & regex_constants::ECMAScript)
#ifndef _GLIBCXX_REGEX_USE_THOMPSON_NFA
&& __policy == _RegexExecutorPolicy::_S_alternate
#endif

7
libstdc++-v3/include/bits/regex_compiler.tcc
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@ -103,9 +103,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
auto __end = _M_nfa._M_insert_dummy();
__alt1._M_append(__end);
__alt2._M_append(__end);
// __alt2 is state._M_next, __alt1 is state._M_alt. The executor
// executes _M_alt before _M_next, as well as executing left
// alternative before right one.
_M_stack.push(_StateSeqT(_M_nfa,
_M_nfa._M_insert_alt(__alt1._M_start,
__alt2._M_start, false),
_M_nfa._M_insert_alt(__alt2._M_start,
__alt1._M_start, false),
__end));
}
}

7
libstdc++-v3/include/bits/regex_executor.h
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@ -173,6 +173,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
void _M_queue(_StateIdT __i, const _ResultsVec& __res)
{ _M_match_queue.emplace_back(__i, __res); }
// Dummy implementations for BFS mode.
_BiIter* _M_get_sol_pos() { return nullptr; }
// Saves states that need to be considered for the next character.
vector<pair<_StateIdT, _ResultsVec>> _M_match_queue;
// Indicates which states are already visited.
@ -192,11 +195,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
bool _M_visited(_StateIdT) const { return false; }
void _M_queue(_StateIdT, const _ResultsVec&) { }
_BiIter* _M_get_sol_pos() { return &_M_sol_pos; }
// To record current solution.
_StateIdT _M_start;
_BiIter _M_sol_pos;
};
public:
_ResultsVec _M_cur_results;
_BiIter _M_current;

47
libstdc++-v3/include/bits/regex_executor.tcc
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@ -82,6 +82,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_M_main_dispatch(_Match_mode __match_mode, __dfs)
{
_M_has_sol = false;
*_M_states._M_get_sol_pos() = _BiIter();
_M_cur_results = _M_results;
_M_dfs(__match_mode, _M_states._M_start);
return _M_has_sol;
@ -338,7 +339,29 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
&& (_M_flags & regex_constants::match_not_null))
_M_has_sol = false;
if (_M_has_sol)
_M_results = _M_cur_results;
{
if (_M_nfa._M_flags & regex_constants::ECMAScript)
_M_results = _M_cur_results;
else // POSIX
{
_GLIBCXX_DEBUG_ASSERT(_M_states._M_get_sol_pos());
// Here's POSIX's logic: match the longest one. However
// we never know which one (lhs or rhs of "|") is longer
// unless we try both of them and compare the results.
// The member variable _M_sol_pos records the end
// position of the last successful match. It's better
// to be larger, because POSIX regex is always greedy.
// TODO: This could be slow.
if (*_M_states._M_get_sol_pos() == _BiIter()
|| std::distance(_M_begin,
*_M_states._M_get_sol_pos())
< std::distance(_M_begin, _M_current))
{
*_M_states._M_get_sol_pos() = _M_current;
_M_results = _M_cur_results;
}
}
}
}
else
{
@ -354,9 +377,25 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
}
break;
case _S_opcode_alternative:
_M_dfs(__match_mode, __state._M_alt);
if (!__dfs_mode || !_M_has_sol)
_M_dfs(__match_mode, __state._M_next);
if (_M_nfa._M_flags & regex_constants::ECMAScript)
{
// TODO: Let DFS support ECMAScript's alternative operation.
_GLIBCXX_DEBUG_ASSERT(!__dfs_mode);
_M_dfs(__match_mode, __state._M_alt);
// Pick lhs if it matches. Only try rhs if it doesn't.
if (!_M_has_sol)
_M_dfs(__match_mode, __state._M_next);
}
else
{
// Try both and compare the result.
// See "case _S_opcode_accept:" handling above.
_M_dfs(__match_mode, __state._M_alt);
auto __has_sol = _M_has_sol;
_M_has_sol = false;
_M_dfs(__match_mode, __state._M_next);
_M_has_sol |= __has_sol;
}
break;
default:
_GLIBCXX_DEBUG_ASSERT(false);

1
libstdc++-v3/include/bits/regex_scanner.h
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@ -67,7 +67,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_S_token_or,
_S_token_closure0,
_S_token_closure1,
_S_token_ungreedy,
_S_token_line_begin,
_S_token_line_end,
_S_token_word_bound, // neg if _M_value[0] == 'n'

52
libstdc++-v3/testsuite/28_regex/algorithms/regex_search/61424.cc Normal file
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@ -0,0 +1,52 @@
// { dg-options "-std=gnu++11" }
// Copyright (C) 2014 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License along
// with this library; see the file COPYING3. If not see
// <http://www.gnu.org/licenses/>.
// PR libstdc++/61424
#include <regex>
#include <testsuite_hooks.h>
#include <testsuite_regex.h>
using namespace std;
using namespace __gnu_test;
int main()
{
regex_constants::syntax_option_type grammar[] = {
regex_constants::ECMAScript, regex_constants::extended,
regex_constants::awk, regex_constants::egrep
};
string sol[] = {
"tour",
"tournament",
"tournament",
"tournament",
};
int i = 0;
for (auto g : grammar)
{
regex re("tour|tournament|tourn", g);
const char str[] = "tournament";
cmatch m;
VERIFY(regex_search_debug(str, m, re));
VERIFY(sol[i] == m[0]);
i++;
}
}