[Bug c++/49021] [4.6 regression] BOOST_FOREACH over vector segfaults at runtime
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49021 Michel MORIN mimomorin at gmail dot com changed: What|Removed |Added CC||mimomorin at gmail dot com --- Comment #13 from Michel MORIN mimomorin at gmail dot com 2011-05-23 09:04:14 UTC --- (In reply to comment #12) This is a bug in BOOST_FOREACH_COMPILE_TIME_CONST_RVALUE_DETECTION. This was already fixed in boost/trunk, and the fix will be released in Boost.1.47. For details, please see the following ticket: [Foreach] Compile-time const rvalue detection fails with gcc 4.6 https://svn.boost.org/trac/boost/ticket/5279
[Bug c++/49021] [4.6 regression] BOOST_FOREACH over vector segfaults at runtime
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49021 --- Comment #8 from Mikael Pettersson mikpe at it dot uu.se 2011-05-20 08:27:39 UTC --- I'm trying to reduce the preprocessed test case, but since I'm not a C++ person this might take some time.
[Bug c++/49021] [4.6 regression] BOOST_FOREACH over vector segfaults at runtime
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49021 --- Comment #9 from Mikael Pettersson mikpe at it dot uu.se 2011-05-20 09:05:31 UTC --- (In reply to comment #8) I'm trying to reduce the preprocessed test case, but since I'm not a C++ person this might take some time. Scratch that, the preprocessed code is way too weird for me.
[Bug c++/49021] [4.6 regression] BOOST_FOREACH over vector segfaults at runtime
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49021 --- Comment #10 from Jonathan Wakely redi at gcc dot gnu.org 2011-05-20 09:48:42 UTC --- (In reply to comment #9) (In reply to comment #8) I'm trying to reduce the preprocessed test case, but since I'm not a C++ person this might take some time. Scratch that, the preprocessed code is way too weird for me. welcome to Boost MPL! ;) there are huge chunks that can be removed (iostreams and locales, reverse_iterators) but reducing it manually is not easy. See http://gcc.gnu.org/wiki/A_guide_to_testcase_reduction for a tool to do it automatically
[Bug c++/49021] [4.6 regression] BOOST_FOREACH over vector segfaults at runtime
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49021 --- Comment #11 from Jonathan Wakely redi at gcc dot gnu.org 2011-05-20 13:44:10 UTC --- Created attachment 24299 -- http://gcc.gnu.org/bugzilla/attachment.cgi?id=24299 reduced by delta
[Bug c++/49021] [4.6 regression] BOOST_FOREACH over vector segfaults at runtime
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49021 Jason Merrill jason at gcc dot gnu.org changed: What|Removed |Added Status|NEW |ASSIGNED AssignedTo|unassigned at gcc dot |jason at gcc dot gnu.org |gnu.org |
[Bug c++/49021] [4.6 regression] BOOST_FOREACH over vector segfaults at runtime
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49021
Jason Merrill jason at gcc dot gnu.org changed:
What|Removed |Added
Status|ASSIGNED|RESOLVED
Resolution||INVALID
--- Comment #12 from Jason Merrill jason at gcc dot gnu.org 2011-05-20
21:25:50 UTC ---
This is a bug in BOOST_FOREACH_COMPILE_TIME_CONST_RVALUE_DETECTION.
The GCC bugfix meant that where previously
true ? boost::foreach_detail_::make_probe(getv()) : (getv())
had the type vector, now it has type const vector.
5.16/3 says:
Otherwise (i.e., if E1 or E2 has a nonclass type, or if they both have class
types but the underlying classes are not either the same or one a base class of
the other): E1 can be converted to match E2 if E1 can be implicitly converted
to the type that expression E2 would have if E2 were converted to a prvalue (or
the type it has, if E2 is a prvalue).
const vector cannot be converted to make_probevector, but
make_probevector has an operator vector, so it can be converted to const
vector, so the type of the conditional expression is const vector.
Here's a reduced example:
template class T
void f (T, int);
template class T
void f (T const, ...);
struct A { };
struct B { operator A () const; };
const A g();
int main()
{
f( (true ? B() : g()), 0);
}
[Bug c++/49021] [4.6 regression] BOOST_FOREACH over vector segfaults at runtime
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49021 --- Comment #6 from Mikael Pettersson mikpe at it dot uu.se 2011-05-19 23:37:54 UTC --- The regression started with r170601: Author: jason Date: Tue Mar 1 22:44:35 2011 New Revision: 170601 URL: http://gcc.gnu.org/viewcvs?root=gccview=revrev=170601 Log: PR c++/47851 * call.c (standard_conversion): Provide requested cv-quals on class rvalue conversion.
[Bug c++/49021] [4.6 regression] BOOST_FOREACH over vector segfaults at runtime
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49021 Jonathan Wakely redi at gcc dot gnu.org changed: What|Removed |Added CC||jason at gcc dot gnu.org --- Comment #7 from Jonathan Wakely redi at gcc dot gnu.org 2011-05-20 00:11:19 UTC --- well if the fix for PR 47851 made G++ correct then this could be a bug in BOOST_FOREACH, but it's hard to know because trying to reduce any MPL code is pretty tedious! Jason, any ideas? do we need to reduce it with delta?
[Bug c++/49021] [4.6 regression] BOOST_FOREACH over vector segfaults at runtime
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49021 --- Comment #1 from Mikael Pettersson mikpe at it dot uu.se 2011-05-17 12:37:52 UTC --- Created attachment 24260 -- http://gcc.gnu.org/bugzilla/attachment.cgi?id=24260 test case, preprocessed on x86_64-linux
[Bug c++/49021] [4.6 regression] BOOST_FOREACH over vector segfaults at runtime
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49021 --- Comment #2 from Mikael Pettersson mikpe at it dot uu.se 2011-05-17 12:38:38 UTC --- Created attachment 24261 -- http://gcc.gnu.org/bugzilla/attachment.cgi?id=24261 test case, non-preprocessed
[Bug c++/49021] [4.6 regression] BOOST_FOREACH over vector segfaults at runtime
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49021 --- Comment #3 from Jonathan Wakely redi at gcc dot gnu.org 2011-05-17 13:52:40 UTC --- The temporary returned by getv() seems to be destroyed too early, before the printf that uses it
[Bug c++/49021] [4.6 regression] BOOST_FOREACH over vector segfaults at runtime
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49021
Jonathan Wakely redi at gcc dot gnu.org changed:
What|Removed |Added
Status|UNCONFIRMED |NEW
Last reconfirmed||2011.05.17 17:24:37
Ever Confirmed|0 |1
--- Comment #4 from Jonathan Wakely redi at gcc dot gnu.org 2011-05-17
17:24:37 UTC ---
slightly reduced, but boost/foreach.hpp still includes thousands of lines
in this version vectorT zeros its data member on destruction, so using it
after destruction is obvious
#include boost/foreach.hpp
templatetypename T
struct vector
{
typedef const T* const_iterator;
~vector() { data = T(); }
T data;
const_iterator begin() const { return data; }
const_iterator end() const { return data + 1; }
};
vectorint v = { 1 };
const vectorint *
getv()
{
vectorint * ret = { v.data };
return ret;
}
int
main(int argc, char **argv)
{
BOOST_FOREACH(int *w, getv())
__builtin_printf(%d\n, *w);
return 0;
}
[Bug c++/49021] [4.6 regression] BOOST_FOREACH over vector segfaults at runtime
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49021
--- Comment #5 from Jonathan Wakely redi at gcc dot gnu.org 2011-05-17
17:28:44 UTC ---
slightly more reduced
#include boost/foreach.hpp
struct vector
{
typedef int* const* const_iterator;
~vector() { data = 0; }
int* data;
const_iterator begin() const { return data; }
const_iterator end() const { return data + 1; }
};
int v = 1;
const vector
getv()
{
vector ret = { v };
return ret;
}
int
main(int argc, char **argv)
{
BOOST_FOREACH(int *w, getv())
__builtin_printf(%d\n, *w);
return 0;
}
