Subject: Re: [PATCH v2] perf build: Install libbpf headers locally when building

From: Arnaldo Carvalho de Melo <[email-masked]>
Date: Sun, 7 Nov 2021 12:30:07 -0300

Em Sun, Nov 07, 2021 at 12:24:45AM +0000, Quentin Monnet escreveu:
> API headers from libbpf should not be accessed directly from the
> library's source directory. Instead, they should be exported with "make
> install_headers". Let's adjust perf's Makefile to install those headers
> locally when building libbpf.
> 
> v2:
> - Fix $(LIBBPF_OUTPUT) when $(OUTPUT) is null.
> - Make sure the recipe for $(LIBBPF_OUTPUT) is not under a "ifdef".

Thanks for the prompt reply, now the cases where it was failing are
passing!

Best regards,

- Arnaldo
 
> Signed-off-by: Quentin Monnet <[email-masked]>
> ---
>  tools/perf/Makefile.perf | 32 +++++++++++++++++++-------------
>  1 file changed, 19 insertions(+), 13 deletions(-)
> 
> diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
> index b856afa6eb52..e01ada5c9876 100644
> --- a/tools/perf/Makefile.perf
> +++ b/tools/perf/Makefile.perf
> @@ -241,7 +241,7 @@ else # force_fixdep
>  
>  LIB_DIR         = $(srctree)/tools/lib/api/
>  TRACE_EVENT_DIR = $(srctree)/tools/lib/traceevent/
> -BPF_DIR         = $(srctree)/tools/lib/bpf/
> +LIBBPF_DIR      = $(srctree)/tools/lib/bpf/
>  SUBCMD_DIR      = $(srctree)/tools/lib/subcmd/
>  LIBPERF_DIR     = $(srctree)/tools/lib/perf/
>  DOC_DIR         = $(srctree)/tools/perf/Documentation/
> @@ -293,7 +293,6 @@ strip-libs = $(filter-out -l%,$(1))
>  ifneq ($(OUTPUT),)
>    TE_PATH=$(OUTPUT)
>    PLUGINS_PATH=$(OUTPUT)
> -  BPF_PATH=$(OUTPUT)
>    SUBCMD_PATH=$(OUTPUT)
>    LIBPERF_PATH=$(OUTPUT)
>  ifneq ($(subdir),)
> @@ -305,7 +304,6 @@ else
>    TE_PATH=$(TRACE_EVENT_DIR)
>    PLUGINS_PATH=$(TRACE_EVENT_DIR)plugins/
>    API_PATH=$(LIB_DIR)
> -  BPF_PATH=$(BPF_DIR)
>    SUBCMD_PATH=$(SUBCMD_DIR)
>    LIBPERF_PATH=$(LIBPERF_DIR)
>  endif
> @@ -324,7 +322,14 @@ LIBTRACEEVENT_DYNAMIC_LIST_LDFLAGS = $(if $(findstring -static,$(LDFLAGS)),,$(DY
>  LIBAPI = $(API_PATH)libapi.a
>  export LIBAPI
>  
> -LIBBPF = $(BPF_PATH)libbpf.a
> +ifneq ($(OUTPUT),)
> +  LIBBPF_OUTPUT = $(abspath $(OUTPUT))/libbpf
> +else
> +  LIBBPF_OUTPUT = $(CURDIR)/libbpf
> +endif
> +LIBBPF_DESTDIR = $(LIBBPF_OUTPUT)
> +LIBBPF_INCLUDE = $(LIBBPF_DESTDIR)/include
> +LIBBPF = $(LIBBPF_OUTPUT)/libbpf.a
>  
>  LIBSUBCMD = $(SUBCMD_PATH)libsubcmd.a
>  
> @@ -829,12 +834,14 @@ $(LIBAPI)-clean:
>  	$(call QUIET_CLEAN, libapi)
>  	$(Q)$(MAKE) -C $(LIB_DIR) O=$(OUTPUT) clean >/dev/null
>  
> -$(LIBBPF): FORCE
> -	$(Q)$(MAKE) -C $(BPF_DIR) O=$(OUTPUT) $(OUTPUT)libbpf.a FEATURES_DUMP=$(FEATURE_DUMP_EXPORT)
> +$(LIBBPF): FORCE | $(LIBBPF_OUTPUT)
> +	$(Q)$(MAKE) -C $(LIBBPF_DIR) FEATURES_DUMP=$(FEATURE_DUMP_EXPORT) \
> +		O= OUTPUT=$(LIBBPF_OUTPUT)/ DESTDIR=$(LIBBPF_DESTDIR) prefix= \
> +		$@ install_headers
>  
>  $(LIBBPF)-clean:
>  	$(call QUIET_CLEAN, libbpf)
> -	$(Q)$(MAKE) -C $(BPF_DIR) O=$(OUTPUT) clean >/dev/null
> +	$(Q)$(RM) -r -- $(LIBBPF_OUTPUT)
>  
>  $(LIBPERF): FORCE
>  	$(Q)$(MAKE) -C $(LIBPERF_DIR) EXTRA_CFLAGS="$(LIBPERF_CFLAGS)" O=$(OUTPUT) $(OUTPUT)libperf.a
> @@ -1034,16 +1041,15 @@ SKELETONS := $(SKEL_OUT)/bpf_prog_profiler.skel.h
>  SKELETONS += $(SKEL_OUT)/bperf_leader.skel.h $(SKEL_OUT)/bperf_follower.skel.h
>  SKELETONS += $(SKEL_OUT)/bperf_cgroup.skel.h
>  
> +$(SKEL_TMP_OUT) $(LIBBPF_OUTPUT):
> +	$(Q)$(MKDIR) -p $@
> +
>  ifdef BUILD_BPF_SKEL
>  BPFTOOL := $(SKEL_TMP_OUT)/bootstrap/bpftool
> -LIBBPF_SRC := $(abspath ../lib/bpf)
> -BPF_INCLUDE := -I$(SKEL_TMP_OUT)/.. -I$(BPF_PATH) -I$(LIBBPF_SRC)/..
> -
> -$(SKEL_TMP_OUT):
> -	$(Q)$(MKDIR) -p $@
> +BPF_INCLUDE := -I$(SKEL_TMP_OUT)/.. -I$(LIBBPF_INCLUDE)
>  
>  $(BPFTOOL): | $(SKEL_TMP_OUT)
> -	CFLAGS= $(MAKE) -C ../bpf/bpftool \
> +	$(Q)CFLAGS= $(MAKE) -C ../bpf/bpftool \
>  		OUTPUT=$(SKEL_TMP_OUT)/ bootstrap
>  
>  VMLINUX_BTF_PATHS ?= $(if $(O),$(O)/vmlinux)				\
> -- 
> 2.32.0

-- 

- Arnaldo