[PATCH] D53153: [OpenCL] Mark kernel functions with default visibility

Fri Nov 30 12:28:58 PST 2018

rjmccall added a comment.

In D53153#1315107 <https://reviews.llvm.org/D53153#1315107>, @yaxunl wrote:

> In D53153#1315039 <https://reviews.llvm.org/D53153#1315039>, @scott.linder wrote:
>
> > In D53153#1314798 <https://reviews.llvm.org/D53153#1314798>, @rjmccall wrote:
> >
> > > You still have the same linkage model for those other languages, right?  Ultimately there's something like a kernel function that has to be declared specially and which becomes the only public interface of the code?
> >
> >
> > I don't think this is true for all languages targeting AMDGPU. For example, HIP has APIs like `hipMemcpyToSymbol` which accept a string identifying a symbol for a variable in global/constant address space. @yaxunl is my understanding about the HIP runtime requiring dynamic symbols for global variables correct here?
>
>
> Right. There is also hipGetSymbolAddress which returns address of a global variable in device memory given the name of the variable. Therefore we cannot hide the global variables.

Okay.  So it's still the case that all symbols will be defined within the linkage unit; it's just that some things might need to get exposed outside of it.

LLVM does provide a `dso_local` attribute which you could use unconditionally on every symbol without actually changing visibility.

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https://reviews.llvm.org/D53153