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authorQuentin Monnet <quentin@isovalent.com>2021-10-07 20:44:27 +0100
committerAndrii Nakryiko <andrii@kernel.org>2021-10-08 11:47:34 -0700
commitb79c2ce3baa99beea7f8410ce3154cc23e26dbd8 (patch)
tree93f5b7898e3909926662071f591309354ad730b2
parent7e3cbd3405cb7b6c036b8984baa694bc55c08e46 (diff)
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 <quentin@isovalent.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20211007194438.34443-2-quentin@isovalent.com
-rw-r--r--tools/lib/bpf/Makefile27
1 files changed, 18 insertions, 9 deletions
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)) \