[Boost-bugs] [Boost C++ Libraries] #9260: Phoenix switch_ statements accessing wrong memory and cause segfault

Subject: [Boost-bugs] [Boost C++ Libraries] #9260: Phoenix switch_ statements accessing wrong memory and cause segfault
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2013-10-18 07:46:19

#9260: Phoenix switch_ statements accessing wrong memory and cause segfault
------------------------------+--------------------------------
 Reporter:  stephan.menzel@…  |       Type:  Bugs
   Status:  new               |  Milestone:  To Be Determined
Component:  None              |    Version:  Boost 1.54.0
 Severity:  Problem           |   Keywords:  phoenix  spirit qi
------------------------------+--------------------------------
 Seth Heeren and I tracked down a problem in phoenix 3's switch_ statements
 that causes a crash in the attached example.

 Judging from valgrind outputs, it appears as if the switch_ accesses
 memory outside it's stack. In the attached case that causes a crash when
 accessing local variables in the enclosing rule.

 To reproduce:

 With this rule:
 qi::rule<It, bool(), qi::locals<bool, unsigned int, double, std::string>,
 Skipper> enclosing;

 defined as:
 enclosing %= condition[_a = _1] >> double_[_val = _a];

 it works.

 If it is defined as:
 enclosing %= condition[_a = _1] >> double_[_c = _1, _val = _a];

 it crashes.

 When not using local variables there is no crash but still  undefined
 behavior caused by the switch_.
 Phoenix 2 does not have this problem.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/9260>
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