Re: [PATCH] libitm: Support sized delete.

[Torvald Riegel <triegel@redhat.com>]

On Fri, 2015-10-30 at 10:19 -0700, Richard Henderson wrote:
> >  #define _ZnwX			S(_Znw,MANGLE_SIZE_T)
> >  #define _ZnaX			S(_Zna,MANGLE_SIZE_T)
> > +#define _ZdlPvX			S(_ZdlPv,MANGLE_SIZE_T)
> >  #define _ZnwXRKSt9nothrow_t	S(S(_Znw,MANGLE_SIZE_T),RKSt9nothrow_t)
> >  #define _ZnaXRKSt9nothrow_t	S(S(_Zna,MANGLE_SIZE_T),RKSt9nothrow_t)
> > +#define _ZdlPvXRKSt9nothrow_t	S(S(_ZdlPv,MANGLE_SIZE_T),RKSt9nothrow_t)

These are symbols that are provided by libstdc++ if it is available
(otherwise, we use dummy implementations, see the other parts of the
patch)...
  
> >  #define _ZGTtnwX		S(_ZGTtnw,MANGLE_SIZE_T)
> >  #define _ZGTtnaX		S(_ZGTtna,MANGLE_SIZE_T)
> > +#define _ZGTtdlPvX		S(_ZGTtdlPv,MANGLE_SIZE_T)
> >  #define _ZGTtnwXRKSt9nothrow_t	S(S(_ZGTtnw,MANGLE_SIZE_T),RKSt9nothrow_t)
> >  #define _ZGTtnaXRKSt9nothrow_t	S(S(_ZGTtna,MANGLE_SIZE_T),RKSt9nothrow_t)
> > +#define _ZGTtdlPvXRKSt9nothrow_t S(S(_ZGTtdlPv,MANGLE_SIZE_T),RKSt9nothrow_t)
> 
> One more thing... Why are there 4 new symbols here...
> 
> > +/* Wrap: operator delete(void* ptr, std::size_t sz)  */
> > +void
> > +_ZGTtdlPvX (void *ptr, size_t sz)
> > +{
> > +  if (ptr)
> > +    gtm_thr()->forget_allocation (ptr, sz, _ZdlPvX);
> > +}
> > +
> > +/* Wrap: operator delete (void *ptr, std::size_t sz, const std::nothrow_t&)  */
> > +void
> > +_ZGTtdlPvXRKSt9nothrow_t (void *ptr, size_t sz, c_nothrow_p nt UNUSED)
> > +{
> > +  if (ptr)
> > +    gtm_thr()->forget_allocation (ptr, sz, delsz_opnt);
> > +}
> > +

... while those are the transactional wrappers that we actually want to
provide and export from libitm.

I'll probably revise the patch in a v2 though depending on how we decide
to handle allocations of exception objects.