[tip:perf/core] tools build: Add CFLAGS_REMOVE_* support

From: tip-bot for Jiri Olsa
Date: Tue Nov 15 2016 - 05:42:34 EST


Commit-ID: 2ec8107d8e0d1d285b2bbf1999e7f4e46b6b535b
Gitweb: http://git.kernel.org/tip/2ec8107d8e0d1d285b2bbf1999e7f4e46b6b535b
Author: Jiri Olsa <jolsa@xxxxxxxxxx>
AuthorDate: Wed, 2 Nov 2016 14:35:47 +0100
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Mon, 14 Nov 2016 11:37:25 -0300

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@xxxxxxxxxx>
Tested-by: Stephane Eranian <eranian@xxxxxxxxxx>
Cc: Andi Kleen <andi@xxxxxxxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: William Cohen <wcohen@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/1478093749-5602-2-git-send-email-jolsa@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/build/Build.include | 4 +++-
tools/build/Documentation/Build.txt | 6 ++++--
2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/tools/build/Build.include b/tools/build/Build.include
index 1dcb95e..c4ae12a 100644
--- a/tools/build/Build.include
+++ b/tools/build/Build.include
@@ -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))

###
diff --git a/tools/build/Documentation/Build.txt b/tools/build/Documentation/Build.txt
index a47bffb..a225874 100644
--- a/tools/build/Documentation/Build.txt
+++ b/tools/build/Documentation/Build.txt
@@ -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.