linux/tools/build/Build.include
Jiri Olsa 2ec8107d8e tools build: Add CFLAGS_REMOVE_* support
Adding support to remove options from final CFLAGS for both object file
and build target. It's now possible to remove CFLAGS options like:

  CFLAGS_REMOVE_krava.o += -Wstrict-prototypes

Committer notes:

This comes from the kernel's kbuild infrastructure, the subset that is
supported in tools/ is being documented at tools/build/Documentation/Build.txt.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Stephane Eranian <eranian@google.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: William Cohen <wcohen@redhat.com>
Link: http://lkml.kernel.org/r/1478093749-5602-2-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-11-14 11:37:25 -03:00

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###
# build: Generic definitions
#
# Lots of this code have been borrowed or heavily inspired from parts
# of kbuild code, which is not credited, but mostly developed by:
#
# Copyright (C) Sam Ravnborg <sam@mars.ravnborg.org>, 2015
# Copyright (C) Linus Torvalds <torvalds@linux-foundation.org>, 2015
#
###
# Convenient variables
comma := ,
squote := '
###
# Name of target with a '.' as filename prefix. foo/bar.o => foo/.bar.o
dot-target = $(dir $@).$(notdir $@)
###
# filename of target with directory and extension stripped
basetarget = $(basename $(notdir $@))
###
# The temporary file to save gcc -MD generated dependencies must not
# contain a comma
depfile = $(subst $(comma),_,$(dot-target).d)
###
# Check if both arguments has same arguments. Result is empty string if equal.
arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \
$(filter-out $(cmd_$@), $(cmd_$(1))) )
###
# Escape single quote for use in echo statements
escsq = $(subst $(squote),'\$(squote)',$1)
# Echo command
# Short version is used, if $(quiet) equals `quiet_', otherwise full one.
echo-cmd = $(if $($(quiet)cmd_$(1)),\
echo ' $(call escsq,$($(quiet)cmd_$(1)))';)
###
# Replace >$< with >$$< to preserve $ when reloading the .cmd file
# (needed for make)
# Replace >#< with >\#< to avoid starting a comment in the .cmd file
# (needed for make)
# Replace >'< with >'\''< to be able to enclose the whole string in '...'
# (needed for the shell)
make-cmd = $(call escsq,$(subst \#,\\\#,$(subst $$,$$$$,$(cmd_$(1)))))
###
# Find any prerequisites that is newer than target or that does not exist.
# PHONY targets skipped in both cases.
any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^)
###
# Copy dependency data into .cmd file
# - gcc -M dependency info
# - command line to create object 'cmd_object :='
dep-cmd = $(if $(wildcard $(fixdep)), \
$(fixdep) $(depfile) $@ '$(make-cmd)' > $(dot-target).tmp; \
rm -f $(depfile); \
mv -f $(dot-target).tmp $(dot-target).cmd, \
printf '\# cannot find fixdep (%s)\n' $(fixdep) > $(dot-target).cmd; \
printf '\# using basic dep data\n\n' >> $(dot-target).cmd; \
cat $(depfile) >> $(dot-target).cmd; \
printf '%s\n' 'cmd_$@ := $(make-cmd)' >> $(dot-target).cmd)
###
# if_changed_dep - execute command if any prerequisite is newer than
# target, or command line has changed and update
# dependencies in the cmd file
if_changed_dep = $(if $(strip $(any-prereq) $(arg-check)), \
@set -e; \
$(echo-cmd) $(cmd_$(1)) && $(dep-cmd))
# if_changed - execute command if any prerequisite is newer than
# target, or command line has changed
if_changed = $(if $(strip $(any-prereq) $(arg-check)), \
@set -e; \
$(echo-cmd) $(cmd_$(1)); \
printf '%s\n' 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd)
###
# C flags to be used in rule definitions, includes:
# - depfile generation
# - global $(CFLAGS)
# - per target C flags
# - per object C flags
# - BUILD_STR macro to allow '-D"$(variable)"' constructs
c_flags_1 = -Wp,-MD,$(depfile),-MT,$@ $(CFLAGS) -D"BUILD_STR(s)=\#s" $(CFLAGS_$(basetarget).o) $(CFLAGS_$(obj))
c_flags_2 = $(filter-out $(CFLAGS_REMOVE_$(basetarget).o), $(c_flags_1))
c_flags = $(filter-out $(CFLAGS_REMOVE_$(obj)), $(c_flags_2))
cxx_flags = -Wp,-MD,$(depfile),-MT,$@ $(CXXFLAGS) -D"BUILD_STR(s)=\#s" $(CXXFLAGS_$(basetarget).o) $(CXXFLAGS_$(obj))
###
## HOSTCC C flags
host_c_flags = -Wp,-MD,$(depfile),-MT,$@ $(CHOSTFLAGS) -D"BUILD_STR(s)=\#s" $(CHOSTFLAGS_$(basetarget).o) $(CHOSTFLAGS_$(obj))