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

From: Jiri Olsa <[email-masked]>
Date: Fri, 5 Feb 2021 13:40:17 +0100

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.

Acked-by: Song Liu <[email-masked]>
Signed-off-by: Jiri Olsa <[email-masked]>
---
 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..1d46a247ec95 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; \
 	find $(if $(OUTPUT),$(OUTPUT),.) -name \*.o -or -name \*.o.cmd -or -name \*.o.d | xargs $(RM)
 
 tags:
-- 
2.26.2