[Openmp-commits] [PATCH] D110193: [RFC] Initial documentation for declare target indirect support.

[Ravi Narayanaswamy via Phabricator via Openmp-commits]

RaviNarayanaswamy added inline comments.


================
Comment at: openmp/libomptarget/docs/declare_target_indirect.md:39
+
+Since all pointers are supposed to be translated/mapped, when program does not use **required unified_shared_memory**, it is possible to avoid generating the runtime dispatch code for indirect function calls. The mapping between host and device address of an indirect function will be established by `libomptarget` during processing of the offload entries table.
+
----------------
vzakhari wrote:
> jdoerfert wrote:
> > How would we translate/map all pointers? I fail to see how we could even identify all (function) pointers (see below). Or did we add wording to the standard to forbid this?
> > 
> > ```
> > char data[sizeof(fp)];
> > memcpy(data, &fp, sizeof(fp));
> > 
> > #pragma omp target map(to:data[:sizeof(fp)])
> > {
> >   void (*fpc)();
> >   memcpy(&fpc, data, sizeof(fp));
> >   fpc(); 
> > }
> > ```
> > 
> > Modulo my syntax errors ;)
> I agree that in this case there will be no translation.  I will remove the words about non-unified_shared_memory "optimization".  Does it sound right?
> I agree that in this case there will be no translation.  I will remove the words about non-unified_shared_memory "optimization".  Does it sound right?

We should get the spec to disallow copy/casting of host pointers and using it  to allow the optimization.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D110193/new/

https://reviews.llvm.org/D110193