Marking C++ allocators as allocators (Was: More function decorations II)

[Richard Guenther]

On Fri, 17 Apr 2009, Martin Jambor wrote:

> Hi,
> 
> On Fri, Apr 17, 2009 at 04:20:40PM +0200, Jan Hubicka wrote:
> > 
> > I wonder, should not be the allocators somehow marked via malloc
> > attribute?  That one provide very important hint for alias analysis and
> > also Martin's IPA stuff.
> > 
> 
> Yep, I'd appreciate such a thing desperately, yet apparently it is not
> as easy as marking the damned things with a flag :-)
> 
> I  have learned  all I  know  about this  issue either  from PR  23383
> (builtin array  operator new is  not marked with malloc  attribute) or
> from the mailing list thread at
> http://gcc.gnu.org/ml/gcc/2007-09/msg00159.html

Fun to re-read this ;)  I will try to put together a summary of the
arguments on the wiki.

One of my next immediate projects for GCC 4.5 is to finally put an
end on this dynamic type/lifetime of memory issues (aka placement
new, aka CHANGE_DYNAMIC_TYPE_EXPR, aka we-cannot-implement-malloc-in-C)
by changing GCCs memory model to make a store of type T to memory M
change its dynamic type to T (for type-based alias analysis).

Richard.