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>
This commit is contained in:
Jiri Olsa 2016-11-02 14:35:47 +01:00 committed by Arnaldo Carvalho de Melo
parent 699c12a7cc
commit 2ec8107d8e
2 changed files with 7 additions and 3 deletions

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@ -89,7 +89,9 @@ if_changed = $(if $(strip $(any-prereq) $(arg-check)), \
# - per target C flags
# - per object C flags
# - BUILD_STR macro to allow '-D"$(variable)"' constructs
c_flags = -Wp,-MD,$(depfile),-MT,$@ $(CFLAGS) -D"BUILD_STR(s)=\#s" $(CFLAGS_$(basetarget).o) $(CFLAGS_$(obj))
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))
###

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@ -135,8 +135,10 @@ CFLAGS
It's possible to alter the standard object C flags in the following way:
CFLAGS_perf.o += '...' - alters CFLAGS for perf.o object
CFLAGS_gtk += '...' - alters CFLAGS for gtk build object
CFLAGS_perf.o += '...' - adds CFLAGS for perf.o object
CFLAGS_gtk += '...' - adds CFLAGS for gtk build object
CFLAGS_REMOVE_perf.o += '...' - removes CFLAGS for perf.o object
CFLAGS_REMOVE_gtk += '...' - removes CFLAGS for gtk build object
This C flags changes has the scope of the Build makefile they are defined in.