Re: [PATCH v2 5/6] tools/build: selftests: Allow versioning LLVM lld

[Arnaldo Carvalho de Melo <acme@kernel.org>]

On Mon, May 18, 2026 at 10:47:53AM +0100, James Clark wrote:
> 
> 
> On 18/05/2026 10:32 am, sashiko-bot@kernel.org wrote:
> > Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
> > - [Medium] Empty USE_LD variable causes clang build failure in selftests when ld.lld is not in PATH.
> > --
> > 
> > commit 371ca22c55bb0fa6502ac06f7b33d63418ad16ff
> > Author: James Clark <james.clark@linaro.org>
> > 
> > tools/build: selftests: Allow versioning LLVM lld
> > 
> > This commit adds an LLD variable to Makefile.include to allow versioning of
> > LLVM's linker, keeping it consistent with the rest of the LLVM toolchain. It
> > modifies the BPF selftests Makefile to resolve the full path of the linker
> > using the command -v shell utility.
> > 
> > > diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
> > > index 6ef6872adbc3e..836e783f0170e 100644
> > > --- a/tools/testing/selftests/bpf/Makefile
> > > +++ b/tools/testing/selftests/bpf/Makefile
> > 
> > [ ... ]
> > 
> > > @@ -245,9 +245,9 @@ $(OUTPUT)/%:%.c
> > >   # LLVM's ld.lld doesn't support all the architectures, so use it only on x86
> > >   ifeq ($(SRCARCH),$(filter $(SRCARCH),x86 riscv))
> > > -LLD := lld
> > > +USE_LD := $(shell command -v $(LLD))
> > 
> > Does this cause the build to fail if the toolchain directory is not in the
> > system PATH?
> > 
> > If a user explicitly specifies the compiler using an absolute path like
> > CLANG=/path/to/clang, but does not add the toolchain directory to their PATH,
> > the command -v utility will return an empty string.
> 
> If they don't use LLVM= and use CLANG= with an absolute path then they need
> to set all the tools with an absolute path. That's the problem that setting
> the path with a prefix for all tools with LLVM= solved.
> 
> I suppose this could _technically_ be a regression, but so could adding any
> new build rule that added a new tool that wouldn't be set in someones
> existing build command. Being that strict would mean we can't ever add new
> tools so I don't think this is an issue. And I don't think there's a way to
> solve this and also respect the documented rules of LLVM=

Hey, this touches several tools and libs, did you get acks besides the
one from Ian?

- Arnaldo