[PATCH 8/8] perf build: Introduce FEATURES_DUMP make variable

From: Arnaldo Carvalho de Melo
Date: Fri Jan 15 2016 - 16:42:41 EST

From: Jiri Olsa <jolsa@xxxxxxxxxx>

Introducing FEATURES_DUMP make variable to provide features
detection dump file and bypass the feature detection.

The intention is to use this during build tests to skip
repeated features detection, like:

Get feature dump static build into /tmp/fd file:
$ make feature-dump FEATURE_DUMP_COPY=/tmp/fd LDFLAGS=-static
BUILD: Doing 'make -j4' parallel build

Auto-detecting system features:
... dwarf: [ OFF ]


FEATURE-DUMP file copied into /tmp/fd

Use /tmp/fd to build perf:
$ make FEATURES_DUMP=/tmp/fd LDFLAGS=-static

$ file perf
perf: ELF 64-bit LSB executable, x86-64, version 1 (GNU/Linux), statically linked, for ...

Suggested-by: Wang Nan <wangnan0@xxxxxxxxxx>
Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Tested-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Zefan Li <lizefan@xxxxxxxxxx>
Cc: pi3orama@xxxxxxx
Link: http://lkml.kernel.org/r/1452830421-77757-7-git-send-email-wangnan0@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
tools/perf/Makefile.perf | 14 +++++++++++++-
tools/perf/config/Makefile | 4 ++++
2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index f758a72df1b3..5d34815c7ccb 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -77,6 +77,9 @@ include config/utilities.mak
# Define NO_AUXTRACE if you do not want AUX area tracing support
# Define NO_LIBBPF if you do not want BPF support
+# Define FEATURES_DUMP to provide features detection dump file
+# and bypass the feature detection

# As per kernel Makefile, avoid funny character set dependencies
unexport LC_ALL
@@ -166,6 +169,15 @@ ifeq ($(config),1)
include config/Makefile

+# The FEATURE_DUMP_EXPORT holds location of the actual
+# FEATURE_DUMP file to be used to bypass feature detection
+# (for bpf or any other subproject)
+ifeq ($(FEATURES_DUMP),)
export prefix bindir sharedir sysconfdir DESTDIR

# sparse is architecture-neutral, which means that we need to tell it
@@ -436,7 +448,7 @@ $(LIBAPI)-clean:
$(Q)$(MAKE) -C $(LIB_DIR) O=$(OUTPUT) clean >/dev/null

$(LIBBPF): fixdep FORCE

$(call QUIET_CLEAN, libbpf)
diff --git a/tools/perf/config/Makefile b/tools/perf/config/Makefile
index e5959c136a19..511141b102e8 100644
--- a/tools/perf/config/Makefile
+++ b/tools/perf/config/Makefile
@@ -181,7 +181,11 @@ LDFLAGS += -Wl,-z,noexecstack

EXTLIBS = -lpthread -lrt -lm -ldl

+ifeq ($(FEATURES_DUMP),)
include $(srctree)/tools/build/Makefile.feature
+include $(FEATURES_DUMP)

ifeq ($(feature-stackprotector-all), 1)
CFLAGS += -fstack-protector-all