Re: [PATCH bpf-next 1/4] tools/resolve_btfids: Build libbpf and libsubcmd in separate directories

From: Jiri Olsa <jolsa@redhat.com>
To: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>, Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andriin@fb.com>,
	Networking <netdev@vger.kernel.org>, bpf <bpf@vger.kernel.org>,
	Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
	Yonghong Song <yhs@fb.com>,
	John Fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@chromium.org>,
	Masahiro Yamada <masahiroy@kernel.org>,
	Michal Marek <michal.lkml@markovi.net>,
	Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>
Subject: Re: [PATCH bpf-next 1/4] tools/resolve_btfids: Build libbpf and libsubcmd in separate directories
Date: Fri, 5 Feb 2021 11:35:07 +0100	[thread overview]
Message-ID: <YB0fW+zEPHa/XKsq@krava> (raw)
In-Reply-To: <CAEf4BzYhnm2tfnuGWXDOAZZmYBnboSZ3JsWjDHM5ortCbaeEjw@mail.gmail.com>

On Thu, Feb 04, 2021 at 04:39:38PM -0800, Andrii Nakryiko wrote:
> On Thu, Feb 4, 2021 at 1:20 PM Jiri Olsa <jolsa@kernel.org> wrote:
> >
> > Setting up separate build directories for libbpf and libpsubcmd,
> > so it's separated from other objects and we don't get them mixed
> > in the future.
> >
> > It also simplifies cleaning, which is now simple rm -rf.
> >
> > Also there's no need for FEATURE-DUMP.libbpf and bpf_helper_defs.h
> > files in .gitignore anymore.
> >
> > Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> > ---
> >  tools/bpf/resolve_btfids/.gitignore |  2 --
> >  tools/bpf/resolve_btfids/Makefile   | 26 +++++++++++---------------
> >  2 files changed, 11 insertions(+), 17 deletions(-)
> >
> > diff --git a/tools/bpf/resolve_btfids/.gitignore b/tools/bpf/resolve_btfids/.gitignore
> > index a026df7dc280..25f308c933cc 100644
> > --- a/tools/bpf/resolve_btfids/.gitignore
> > +++ b/tools/bpf/resolve_btfids/.gitignore
> > @@ -1,4 +1,2 @@
> > -/FEATURE-DUMP.libbpf
> > -/bpf_helper_defs.h
> >  /fixdep
> >  /resolve_btfids
> > diff --git a/tools/bpf/resolve_btfids/Makefile b/tools/bpf/resolve_btfids/Makefile
> > index bf656432ad73..b780b3a9fb07 100644
> > --- a/tools/bpf/resolve_btfids/Makefile
> > +++ b/tools/bpf/resolve_btfids/Makefile
> > @@ -28,22 +28,22 @@ OUTPUT ?= $(srctree)/tools/bpf/resolve_btfids/
> >  LIBBPF_SRC := $(srctree)/tools/lib/bpf/
> >  SUBCMD_SRC := $(srctree)/tools/lib/subcmd/
> >
> > -BPFOBJ     := $(OUTPUT)/libbpf.a
> > -SUBCMDOBJ  := $(OUTPUT)/libsubcmd.a
> > +BPFOBJ     := $(OUTPUT)/libbpf/libbpf.a
> > +SUBCMDOBJ  := $(OUTPUT)/libsubcmd/libsubcmd.a
> >
> >  BINARY     := $(OUTPUT)/resolve_btfids
> >  BINARY_IN  := $(BINARY)-in.o
> >
> >  all: $(BINARY)
> >
> > -$(OUTPUT):
> > +$(OUTPUT) $(OUTPUT)/libbpf $(OUTPUT)/libsubcmd:
> >         $(call msg,MKDIR,,$@)
> > -       $(Q)mkdir -p $(OUTPUT)
> > +       $(Q)mkdir -p $(@)
> >
> > -$(SUBCMDOBJ): fixdep FORCE
> > -       $(Q)$(MAKE) -C $(SUBCMD_SRC) OUTPUT=$(OUTPUT)
> > +$(SUBCMDOBJ): fixdep FORCE | $(OUTPUT)/libsubcmd
> > +       $(Q)$(MAKE) -C $(SUBCMD_SRC) OUTPUT=$(abspath $(dir $@))/ $(abspath $@)
> >
> > -$(BPFOBJ): $(wildcard $(LIBBPF_SRC)/*.[ch] $(LIBBPF_SRC)/Makefile) | $(OUTPUT)
> > +$(BPFOBJ): $(wildcard $(LIBBPF_SRC)/*.[ch] $(LIBBPF_SRC)/Makefile) | $(OUTPUT)/libbpf
> >         $(Q)$(MAKE) $(submake_extras) -C $(LIBBPF_SRC)  OUTPUT=$(abspath $(dir $@))/ $(abspath $@)
> >
> >  CFLAGS := -g \
> > @@ -57,23 +57,19 @@ LIBS = -lelf -lz
> >  export srctree OUTPUT CFLAGS Q
> >  include $(srctree)/tools/build/Makefile.include
> >
> > -$(BINARY_IN): fixdep FORCE
> > +$(BINARY_IN): fixdep FORCE | $(OUTPUT)
> >         $(Q)$(MAKE) $(build)=resolve_btfids
> >
> >  $(BINARY): $(BPFOBJ) $(SUBCMDOBJ) $(BINARY_IN)
> >         $(call msg,LINK,$@)
> >         $(Q)$(CC) $(BINARY_IN) $(LDFLAGS) -o $@ $(BPFOBJ) $(SUBCMDOBJ) $(LIBS)
> >
> > -libsubcmd-clean:
> > -       $(Q)$(MAKE) -C $(SUBCMD_SRC) OUTPUT=$(OUTPUT) clean
> > -
> > -libbpf-clean:
> > -       $(Q)$(MAKE) -C $(LIBBPF_SRC) OUTPUT=$(OUTPUT) clean
> > -
> > -clean: libsubcmd-clean libbpf-clean fixdep-clean
> > +clean: fixdep-clean
> >         $(call msg,CLEAN,$(BINARY))
> >         $(Q)$(RM) -f $(BINARY); \
> >         $(RM) -rf $(if $(OUTPUT),$(OUTPUT),.)/feature; \
> > +       $(RM) -rf $(OUTPUT)libbpf; \
> > +       $(RM) -rf $(OUTPUT)libsubcmd; \
> 
> If someone specifies OUTPUT=bla, you will attempt to delete blalibbpf,
> not bla/libbpf

will add missing '/', thanks

jirka