[PATCH 03/50] tools/perf/build: Add 'autodep' functionality, generate feature test dependencies automatically

From: Ingo Molnar
Date: Mon Oct 07 2013 - 08:11:15 EST


Use GCC's -MD feature to generate a dependency file for each feature test .c file,
and include that .d file in the config/feature-checks/Makefile.

This allows us to do two things:

- speed up feature tests
- detect removal or changes in build dependencies - including system libraries/headers

Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Link: http://lkml.kernel.org/n/tip-Jfma8pmPnnqzpxjbs3hpgmsj@xxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
tools/perf/config/feature-checks/Makefile | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/tools/perf/config/feature-checks/Makefile b/tools/perf/config/feature-checks/Makefile
index b3f6372..4708cca 100644
--- a/tools/perf/config/feature-checks/Makefile
+++ b/tools/perf/config/feature-checks/Makefile
@@ -1,16 +1,20 @@

FILES=test-hello

+CC := $(CC) -MD
+
all: $(FILES)

BUILD = $(CC) -o $(OUTPUT)$@ $@.c

###############################

-test-hello: test-hello.c
+test-hello:
$(BUILD)

+-include *.d */*.d
+
###############################

clean:
- rm -f $(FILES)
+ rm -f $(FILES) *.d
--
1.7.11.7

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