Re: CVS commit: src

[maya%netbsd.org@localhost]

On Tue, Jan 01, 2019 at 04:02:01PM +0000, Robert Swindells wrote:
> 
> maya%NetBSD.org@localhost wrote:
> >On Tue, Jan 01, 2019 at 03:34:47PM +0100, Martin Husemann wrote:
> >> On Tue, Jan 01, 2019 at 02:22:54PM +0000, maya%netbsd.org@localhost wrote:
> >> > I'm stuck between the hammer and the anvil here.
> >> > I'd like NetBSD to use a recent MesaLib, the kind that uses LLVM.
> >> 
> >> Can you explain how the MesaLib build uses llvm?
> >> 
> >> This kinda sounds like you need a special build time binary that would
> >> live in $TOOLDIR and it is not exactly clear how installing some headers
> >> helps building this tool (as you can not assume a NetBSD build host).
> >> 
> >> Martin
> >
> >I haven't dug up too much into it in the past, so this was fun to
> >discover:
> >
> >MesaLib is a compiler for turning agnostic representations like GLSL and
> >SPIR-V into hardware appropriate ones. It has passes and intermediate
> >formats (plural!) and everything.
> >
> >AMD drivers use LLVM as a step in the process, they defined an AMDGPU as
> >a target architecture.
> >
> >I'm not sure how a JIT works, but swrast uses LLVM for its JIT.
> >
> >at least on the pkgsrc build, swrast and radeonsi are dynamically linked
> >with libLLVM.
> 
> How does the usage of libLLVM from MesaLib make use of the LLVM headers
> at *runtime* ?
> 
> If they are not needed at runtime then why do they need to be installed
> on a target machine ?

it doesn't need the headers at runtime. joerg is currently objecting to
installing the llvm libraries too.