From b79c2ce3baa99beea7f8410ce3154cc23e26dbd8 Mon Sep 17 00:00:00 2001 From: Quentin Monnet Date: Thu, 7 Oct 2021 20:44:27 +0100 Subject: libbpf: Skip re-installing headers file if source is older than target The "install_headers" target in libbpf's Makefile would unconditionally export all API headers to the target directory. When those headers are installed to compile another application, this means that make always finds newer dependencies for the source files relying on those headers, and deduces that the targets should be rebuilt. Avoid that by making "install_headers" depend on the source header files, and (re-)install them only when necessary. Signed-off-by: Quentin Monnet Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20211007194438.34443-2-quentin@isovalent.com --- tools/lib/bpf/Makefile | 27 ++++++++++++++++++--------- 1 file changed, 18 insertions(+), 9 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile index 41e4f78dbad5..9c6804ca5b45 100644 --- a/tools/lib/bpf/Makefile +++ b/tools/lib/bpf/Makefile @@ -241,15 +241,24 @@ install_lib: all_cmd $(call do_install_mkdir,$(libdir_SQ)); \ cp -fpR $(LIB_FILE) $(DESTDIR)$(libdir_SQ) -INSTALL_HEADERS = bpf.h libbpf.h btf.h libbpf_common.h libbpf_legacy.h xsk.h \ - bpf_helpers.h $(BPF_GENERATED) bpf_tracing.h \ - bpf_endian.h bpf_core_read.h skel_internal.h \ - libbpf_version.h - -install_headers: $(BPF_GENERATED) - $(call QUIET_INSTALL, headers) \ - $(foreach hdr,$(INSTALL_HEADERS), \ - $(call do_install,$(hdr),$(prefix)/include/bpf,644);) +SRC_HDRS := bpf.h libbpf.h btf.h libbpf_common.h libbpf_legacy.h xsk.h \ + bpf_helpers.h bpf_tracing.h bpf_endian.h bpf_core_read.h \ + skel_internal.h libbpf_version.h +GEN_HDRS := $(BPF_GENERATED) + +INSTALL_PFX := $(DESTDIR)$(prefix)/include/bpf +INSTALL_SRC_HDRS := $(addprefix $(INSTALL_PFX)/, $(SRC_HDRS)) +INSTALL_GEN_HDRS := $(addprefix $(INSTALL_PFX)/, $(notdir $(GEN_HDRS))) + +$(INSTALL_SRC_HDRS): $(INSTALL_PFX)/%.h: %.h + $(call QUIET_INSTALL, $@) \ + $(call do_install,$<,$(prefix)/include/bpf,644) + +$(INSTALL_GEN_HDRS): $(INSTALL_PFX)/%.h: $(OUTPUT)%.h + $(call QUIET_INSTALL, $@) \ + $(call do_install,$<,$(prefix)/include/bpf,644) + +install_headers: $(BPF_GENERATED) $(INSTALL_SRC_HDRS) $(INSTALL_GEN_HDRS) install_pkgconfig: $(PC_FILE) $(call QUIET_INSTALL, $(PC_FILE)) \ -- cgit v1.2.3