tools/scripts/Makefile.include may expand EXTRA_CFLAGS in a future change. This could alter the initialization of CFLAGS, as the default options "-g -O2" would never be set once EXTRA_CFLAGS is expanded.
Prepare for this by moving the CFLAGS initialization before including tools/scripts/Makefile.include, so it is not affected by the extended EXTRA_CFLAGS. Append EXTRA_CFLAGS to CFLAGS only after including Makefile.include and place it last so that the extra flags propagate properly and can override the default options. tools/scripts/Makefile.include already appends $(CLANG_CROSS_FLAGS) to CFLAGS, the Makefile appends $(CLANG_CROSS_FLAGS) again, remove the redundant append. Signed-off-by: Leo Yan <[email protected]> --- tools/lib/bpf/Makefile | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile index 168140f8e6461bd06db40e23d21a3fb8847ccbf4..eca584fb061e16013e76827e4203f6be0477a73e 100644 --- a/tools/lib/bpf/Makefile +++ b/tools/lib/bpf/Makefile @@ -49,6 +49,14 @@ man_dir_SQ = '$(subst ','\'',$(man_dir))' export man_dir man_dir_SQ INSTALL export DESTDIR DESTDIR_SQ +# Defer assigning EXTRA_CFLAGS to CFLAGS until after including +# tools/scripts/Makefile.include, as it may add flags to EXTRA_CFLAGS. +ifdef EXTRA_CFLAGS + CFLAGS := +else + CFLAGS := -g -O2 +endif + include $(srctree)/tools/scripts/Makefile.include # copy a bit from Linux kbuild @@ -70,13 +78,6 @@ LIB_TARGET = libbpf.a libbpf.so.$(LIBBPF_VERSION) LIB_FILE = libbpf.a libbpf.so* PC_FILE = libbpf.pc -# Set compile option CFLAGS -ifdef EXTRA_CFLAGS - CFLAGS := $(EXTRA_CFLAGS) -else - CFLAGS := -g -O2 -endif - # Append required CFLAGS override CFLAGS += -std=gnu89 override CFLAGS += $(EXTRA_WARNINGS) -Wno-switch-enum @@ -84,7 +85,7 @@ override CFLAGS += -Werror -Wall override CFLAGS += $(INCLUDES) override CFLAGS += -fvisibility=hidden override CFLAGS += -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -override CFLAGS += $(CLANG_CROSS_FLAGS) +override CFLAGS += $(EXTRA_CFLAGS) # flags specific for shared library SHLIB_FLAGS := -DSHARED -fPIC -- 2.34.1
