Re: [RFC PATCH bpf-next v5 8/8] selftests/bpf: build each test runner instance in its own sub-make

[Eduard Zingerman <eddyz87@gmail.com>]

On Sat, 2026-08-22 at 17:34 -0700, Mykola Lysenko wrote:

...

> > > -# Define test_progs BPF-GCC-flavored test runner.
> > >  ifneq ($(BPF_GCC),)
> > > -TRUNNER_BPF_BUILD_RULE := GCC_BPF_BUILD_RULE
> > > -TRUNNER_BPF_CFLAGS := $(BPF_CFLAGS) $(call get_sys_includes,gcc,)
> > > -$(eval $(call DEFINE_TEST_RUNNER,test_progs,bpf_gcc))
> > > +# Sys includes come from the *host* gcc, not $(BPF_GCC) - bpf-gcc's own
> > > +# search path lacks the host's asm-generic/ headers.
> > > +GCC_SYS_INCLUDES := $(call get_sys_includes,gcc,)
> > > +
> > > +$(OUTPUT)/test_progs-bpf_gcc: $(RUNNER_PREREQS) FORCE
> > > +     +$(Q)$(RUNNER_MAKE) RUNNER=test_progs FLAVOR=bpf_gcc TESTS_DIR=prog_tests \
> > > +             BPF_CC='$(BPF_GCC)' BPF_CC_MSG=GCC-BPF                          \
> > > +             BPF_SYS_INCLUDES='$(GCC_SYS_INCLUDES)'                          \
> > > +             BPF_CC_FLAGS='-DBPF_NO_PRESERVE_ACCESS_INDEX -Wno-attributes -O2'
> > >  endif
> > 
> > Did you test the bpf_gcc flavor?
> > I have a recipe to build the toolchain somewhere, if you need it.
> 
> Two data points. The BPF CI GCC-BPF job builds the flavor and is
> green on this series. Locally I ran it with the bpf-gcc Ubuntu
> packages (gcc 14 snapshot, 2024): the machinery works - 671 of 982
> programs compile, the ones that old gcc cannot handle skip cleanly
> under BPF_STRICT_BUILD=0, skeletons generate or skip with the
> objects - until resolve_btfids aborts on btf_data.bpf.o carrying no
> .BTF section, which that gcc does not emit; the BTFIDS recipe step is
> not covered by the permissive suffix in the current Makefile either,
> so the behavior matches stock. I would take your toolchain recipe -
> with a current gcc-bpf I expect the flavor to complete, and I'd like
> it in my pre-send checklist.

#!/bin/bash

set -e

base=/home/ezingerman/gcc-bpf-toolchain
build_base=$base/build
gcc_repo=$base/gcc
gcc_build_dir=$build_base/gcc
binutils_repo=$base/binutils-gdb
binutils_build_dir=$build_base/binutils
install_dir=$base/install

mkdir -p $gcc_build_dir $binutils_build_dir

cd $binutils_build_dir
$binutils_repo/configure --target=bpf-unknown-none --prefix=$install_dir --disable-gdb
make -j
make install

export PATH="$install_dir/bin:$PATH"

cd $gcc_build_dir
$gcc_repo/configure --target=bpf-unknown-none --prefix=$install_dir --enable-languages=c,lto --disable-multilib
make -j
make install