The dependency will be checked anyway after Kbuild descends into a sub-directory. Skip object/source dependency checks in top Makefile. VPATH can be simpler since the top Makefile no longer checks the preprense of the source file, which is located in in the external module directory. [Pros] - Code is cleaner - It can compile an object from a generated source file For example, $ make crypto/rsapubkey.asn1.o ... ASN.1 crypto/rsapubkey.asn1.c CC crypto/rsapubkey.asn1.o [Cons] - The top Makefile does not let it fail immediately when a user tries to build a wrong object. Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx> --- Makefile | 38 +++++++++----------------------------- 1 file changed, 9 insertions(+), 29 deletions(-) diff --git a/Makefile b/Makefile index f7f1aa1..8bf0ed6 100644 --- a/Makefile +++ b/Makefile @@ -219,7 +219,7 @@ objtree := . src := $(srctree) obj := $(objtree) -VPATH := $(srctree)$(if $(KBUILD_EXTMOD),:$(KBUILD_EXTMOD)) +VPATH := $(srctree) export srctree objtree VPATH @@ -1686,31 +1686,14 @@ tools/%: FORCE # target-dir => where to store outputfile # build-dir => directory in kernel source tree to use -ifeq ($(KBUILD_EXTMOD),) - build-dir = $(patsubst %/,%,$(dir $@)) - target-dir = $(dir $@) -else - zap-slash=$(filter-out .,$(patsubst %/,%,$(dir $@))) - build-dir = $(KBUILD_EXTMOD)$(if $(zap-slash),/$(zap-slash)) - target-dir = $(if $(KBUILD_EXTMOD),$(dir $<),$(dir $@)) -endif - -%.s: %.c prepare FORCE - $(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@) -%.i: %.c prepare FORCE - $(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@) -%.o: %.c prepare FORCE - $(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@) -%.lst: %.c prepare FORCE - $(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@) -%.s: %.S prepare FORCE - $(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@) -%.o: %.S prepare FORCE - $(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@) -%.symtypes: %.c prepare FORCE - $(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@) -%.ll: %.c prepare FORCE - $(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@) +build-target = $(if $(KBUILD_EXTMOD), $(KBUILD_EXTMOD)/)$@ +build-dir = $(patsubst %/,%,$(dir $(build-target))) + +%.i %.ll %.lst %.o %.s %.symtypes: prepare FORCE + $(Q)$(MAKE) $(build)=$(build-dir) $(build-target) + +%.ko: %.o + $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost # Modules PHONY += / @@ -1720,9 +1703,6 @@ PHONY += / Documentation/ samples/: headers_install %/: prepare FORCE $(Q)$(MAKE) KBUILD_MODULES=1 $(build)=$(build-dir) -%.ko: prepare FORCE - $(Q)$(MAKE) $(build)=$(build-dir) $(@:.ko=.o) - $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost # FIXME Should go into a make.lib or something # =========================================================================== -- 2.7.4