1### 2# build: Generic definitions 3# 4# Lots of this code have been borrowed or heavily inspired from parts 5# of kbuild code, which is not credited, but mostly developed by: 6# 7# Copyright (C) Sam Ravnborg <sam@mars.ravnborg.org>, 2015 8# Copyright (C) Linus Torvalds <torvalds@linux-foundation.org>, 2015 9# 10 11### 12# Convenient variables 13comma := , 14squote := ' 15 16### 17# Name of target with a '.' as filename prefix. foo/bar.o => foo/.bar.o 18dot-target = $(dir $@).$(notdir $@) 19 20### 21# filename of target with directory and extension stripped 22basetarget = $(basename $(notdir $@)) 23 24### 25# The temporary file to save gcc -MD generated dependencies must not 26# contain a comma 27depfile = $(subst $(comma),_,$(dot-target).d) 28 29### 30# Check if both arguments has same arguments. Result is empty string if equal. 31arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \ 32 $(filter-out $(cmd_$@), $(cmd_$(1))) ) 33 34### 35# Escape single quote for use in echo statements 36escsq = $(subst $(squote),'\$(squote)',$1) 37 38# Echo command 39# Short version is used, if $(quiet) equals `quiet_', otherwise full one. 40echo-cmd = $(if $($(quiet)cmd_$(1)),\ 41 echo ' $(call escsq,$($(quiet)cmd_$(1)))';) 42 43### 44# Replace >$< with >$$< to preserve $ when reloading the .cmd file 45# (needed for make) 46# Replace >#< with >\#< to avoid starting a comment in the .cmd file 47# (needed for make) 48# Replace >'< with >'\''< to be able to enclose the whole string in '...' 49# (needed for the shell) 50make-cmd = $(call escsq,$(subst \#,\\\#,$(subst $$,$$$$,$(cmd_$(1))))) 51 52### 53# Find any prerequisites that is newer than target or that does not exist. 54# PHONY targets skipped in both cases. 55any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^) 56 57### 58# if_changed_dep - execute command if any prerequisite is newer than 59# target, or command line has changed and update 60# dependencies in the cmd file 61if_changed_dep = $(if $(strip $(any-prereq) $(arg-check)), \ 62 @set -e; \ 63 $(echo-cmd) $(cmd_$(1)); \ 64 cat $(depfile) > $(dot-target).cmd; \ 65 printf '%s\n' 'cmd_$@ := $(make-cmd)' >> $(dot-target).cmd) 66 67# if_changed - execute command if any prerequisite is newer than 68# target, or command line has changed 69if_changed = $(if $(strip $(any-prereq) $(arg-check)), \ 70 @set -e; \ 71 $(echo-cmd) $(cmd_$(1)); \ 72 printf '%s\n' 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd) 73 74### 75# C flags to be used in rule definitions, includes: 76# - depfile generation 77# - global $(CFLAGS) 78# - per target C flags 79# - per object C flags 80# - BUILD_STR macro to allow '-D"$(variable)"' constructs 81c_flags = -Wp,-MD,$(depfile),-MT,$@ $(CFLAGS) -D"BUILD_STR(s)=\#s" $(CFLAGS_$(basetarget).o) $(CFLAGS_$(obj)) 82