[Bug target/36861] [4.5/4.6 Regression] boost's compressed avl confuses GCC

[igaztanaga at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36861

--- Comment #38 from Ion Gaztañaga <igaztanaga at gmail dot com> 2011-01-18 19:15:22 UTC ---
Thanks Richard for the detailed report. The fact is that the next standard is
trying to support relative pointers for container implementations (much like
Boost.Interprocess does), to be able to place containers in shared memory. In
those cases the relative pointers stores the difference between "this" and the
pointee, which is what boost::interprocess::offset_ptr does.

It is certainly outside the standard right now and the standard won't include
such "relative pointer" class, but it will require to container implementations
to support them as allocator::pointer types. It would be important to find a
way to use smart pointers, maybe with some existing annotation/attribute to
avoid optimizing away that relative addressing, so that there is always away to
compute the pointee address based on "this" + this->m_offset. It is also
important to support smart pointers created on the stack pointing to global
objects (temporaries, function arguments, etc.)

I know this is outside the bug, but it will be certainly a common question when
using GCC and next standard containers. Thanks