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

On Thu, Feb 04, 2021 at 04:39:38PM -0800, Andrii Nakryiko wrote:

On Thu, Feb 4, 2021 at 1:20 PM Jiri Olsa [off-list ref] wrote:

quoted

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