Subject: [PATCHv4 0/6] perf/bpftool: Allow to link libbpf dynamically

From: Jiri Olsa <[email-masked]>
Date: Mon, 2 Dec 2019 14:18:40 +0100

hi,
adding support to link bpftool with libbpf dynamically,
and config change for perf.

It's now possible to use:
  $ make -C tools/bpf/bpftool/ LIBBPF_DYNAMIC=1

which will detect libbpf devel package and if found, link it with bpftool.

It's possible to use arbitrary installed libbpf:
  $ make -C tools/bpf/bpftool/ LIBBPF_DYNAMIC=1 LIBBPF_DIR=/tmp/libbpf/

I based this change on top of Arnaldo's perf/core, because
it contains libbpf feature detection code as dependency.

Also available in:
  git://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git
  libbpf/dyn

v4 changes:
  - based on Toke's v3 post, there's no need for additional API exports:

    Since bpftool uses bits of libbpf that are not exported as public API in
    the .so version, we also pass in libbpf.a to the linker, which allows it to
    pick up the private functions from the static library without having to
    expose them as ABI.

  - changing some Makefile variable names
  - documenting LIBBPF_DYNAMIC and LIBBPF_DIR in the Makefile comment
  - extending test_bpftool_build.sh with libbpf dynamic link

thanks,
jirka

---
Jiri Olsa (6):
      perf tools: Allow to specify libbpf install directory
      bpftool: Allow to link libbpf dynamically
      bpftool: Rename BPF_DIR Makefile variable to LIBBPF_SRC_DIR
      bpftool: Rename LIBBPF_OUTPUT Makefile variable to LIBBPF_BUILD_OUTPUT
      bpftool: Rename LIBBPF_PATH Makefile variable to LIBBPF_BUILD_PATH
      selftests, bpftool: Add build test for libbpf dynamic linking

 tools/bpf/bpftool/Makefile                        | 54 ++++++++++++++++++++++++++++++++++++++++++++++--------
 tools/perf/Makefile.config                        | 27 ++++++++++++++++++++-------
 tools/testing/selftests/bpf/test_bpftool_build.sh | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 119 insertions(+), 15 deletions(-)