Re: [PATCH RFC] tools: Factor Clang, LLC and LLVM utils definitions

On Sat, Jan 16, 2021 at 10:54:04AM +0100, Sedat Dilek wrote:

When dealing with BPF/BTF/pahole and DWARF v5 I wanted to build bpftool.

While looking into the source code I found duplicate assignments
in misc tools for the LLVM eco system, e.g. clang and llvm-objcopy.

Move the Clang, LLC and/or LLVM utils definitions to
tools/scripts/Makefile.include file and add missing
includes where needed.
Honestly, I was inspired by commit c8a950d0d3b9
("tools: Factor HOSTCC, HOSTLD, HOSTAR definitions").

I tested with bpftool and perf on Debian/testing AMD64 and
LLVM/Clang v11.1.0-rc1.

Build instructions:

[ make and make-options ]
MAKE="make V=1"
MAKE_OPTS="HOSTCC=clang HOSTCXX=clang++ HOSTLD=ld.lld CC=clang LD=ld.lld LLVM=1 LLVM_IAS=1"
MAKE_OPTS="$MAKE_OPTS PAHOLE=/opt/pahole/bin/pahole"

[ clean-up ]
$MAKE $MAKE_OPTS -C tools/ clean

[ bpftool ]
$MAKE $MAKE_OPTS -C tools/bpf/bpftool/

[ perf ]
PYTHON=python3 $MAKE $MAKE_OPTS -C tools/perf/

I was careful with respecting the user's wish to override custom compiler,
linker, GNU/binutils and/or LLVM utils settings.

Some personal notes:
1. I have NOT tested with cross-toolchain for other archs (cross compiler/linker etc.).
2. This patch is on top of Linux v5.11-rc3.

I hope to get some feedback from especially Linux-bpf folks.

Signed-off-by: Sedat Dilek <redacted>
---
 tools/bpf/bpftool/Makefile                  | 2 --
 tools/bpf/runqslower/Makefile               | 3 ---
 tools/build/feature/Makefile                | 4 ++--
 tools/perf/Makefile.perf                    | 1 -

for tools/build and tools/perf

Acked-by: Jiri Olsa <redacted>

jirka

SNIP