[PATCH 2/4] perf tools: Force fixdep compilation at the start of the build

[Jiri Olsa]

The fixdep tool needs to be built before everything else,
because it fixes every object dependency file.

We handle this currently by making all objects to depend
on fixdep, which is error prone and is easily forgotten
when new object is added.

Instead of this, this patch force fixdep tool to be built
as the first target in the separate make session. This way
we don't need to handle extra fixdep dependencies and we are
certain there's no fixdep race with any parallel make job.

Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Link: http://lkml.kernel.org/n/tip-b6wi5cssl8apu74o2kbfheag@xxxxxxxxxxxxxx
---
 tools/perf/Makefile.perf | 50 ++++++++++++++++++++++++++++++++++++------------
 1 file changed, 38 insertions(+), 12 deletions(-)

diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index 9e5a6e1a387d..33b1d9f8555f 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -181,6 +181,35 @@ ifeq ($(filter-out $(NON_CONFIG_TARGETS),$(MAKECMDGOALS)),)
 endif
 endif
 
+# The fixdep build - we force fixdep tool to be built as
+# the first target in the separate make session not to be
+# disturbed by any parallel make jobs. Once fixdep is done
+# we issue the requested build with FIXDEP=1 variable.
+#
+# The fixdep build is disabled for $(NON_CONFIG_TARGETS)
+# targets, because it's not necessary.
+
+ifdef FIXDEP
+  force_fixdep := 0
+else
+  force_fixdep := $(config)
+endif
+
+export srctree OUTPUT RM CC CXX LD AR CFLAGS CXXFLAGS V BISON FLEX AWK
+export HOSTCC HOSTLD HOSTAR
+
+include $(srctree)/tools/build/Makefile.include
+
+ifeq ($(force_fixdep),1)
+goals := $(filter-out all sub-make, $(MAKECMDGOALS))
+
+$(goals) all: sub-make
+
+sub-make: fixdep
+	$(Q)$(MAKE) FIXDEP=1 -f Makefile.perf $(goals)
+
+else # force_fixdep
+
 # Set FEATURE_TESTS to 'all' so all possible feature checkers are executed.
 # Without this setting the output feature dump file misses some features, for
 # example, liberty. Select all checkers so we won't get an incomplete feature
@@ -365,10 +394,6 @@ strip: $(PROGRAMS) $(OUTPUT)perf
 
 PERF_IN := $(OUTPUT)perf-in.o
 
-export srctree OUTPUT RM CC CXX LD AR CFLAGS CXXFLAGS V BISON FLEX AWK
-export HOSTCC HOSTLD HOSTAR
-include $(srctree)/tools/build/Makefile.include
-
 JEVENTS       := $(OUTPUT)pmu-events/jevents
 JEVENTS_IN    := $(OUTPUT)pmu-events/jevents-in.o
 
@@ -487,7 +512,7 @@ $(OUTPUT)perf: $(PERFLIBS) $(PERF_IN) $(PMU_EVENTS_IN) $(LIBTRACEEVENT_DYNAMIC_L
 	$(QUIET_LINK)$(CC) $(CFLAGS) $(LDFLAGS) $(LIBTRACEEVENT_DYNAMIC_LIST_LDFLAGS) \
 		$(PERF_IN) $(PMU_EVENTS_IN) $(LIBS) -o $@
 
-$(GTK_IN): fixdep FORCE
+$(GTK_IN): FORCE
 	$(Q)$(MAKE) $(build)=gtk
 
 $(OUTPUT)libperf-gtk.so: $(GTK_IN) $(PERFLIBS)
@@ -536,7 +561,7 @@ endif
 __build-dir = $(subst $(OUTPUT),,$(dir $@))
 build-dir   = $(if $(__build-dir),$(__build-dir),.)
 
-prepare: $(OUTPUT)PERF-VERSION-FILE $(OUTPUT)common-cmds.h fixdep archheaders
+prepare: $(OUTPUT)PERF-VERSION-FILE $(OUTPUT)common-cmds.h archheaders
 
 $(OUTPUT)%.o: %.c prepare FORCE
 	$(Q)$(MAKE) -f $(srctree)/tools/build/Makefile.build dir=$(build-dir) $@
@@ -586,7 +611,7 @@ $(patsubst perf-%,%.o,$(PROGRAMS)): $(wildcard */*.h)
 
 LIBPERF_IN := $(OUTPUT)libperf-in.o
 
-$(LIBPERF_IN): prepare fixdep FORCE
+$(LIBPERF_IN): prepare FORCE
 	$(Q)$(MAKE) $(build)=libperf
 
 $(LIB_FILE): $(LIBPERF_IN)
@@ -594,10 +619,10 @@ $(LIB_FILE): $(LIBPERF_IN)
 
 LIBTRACEEVENT_FLAGS += plugin_dir=$(plugindir_SQ)
 
-$(LIBTRACEEVENT): fixdep FORCE
+$(LIBTRACEEVENT): FORCE
 	$(Q)$(MAKE) -C $(TRACE_EVENT_DIR) $(LIBTRACEEVENT_FLAGS) O=$(OUTPUT) $(OUTPUT)libtraceevent.a
 
-libtraceevent_plugins: fixdep FORCE
+libtraceevent_plugins: FORCE
 	$(Q)$(MAKE) -C $(TRACE_EVENT_DIR) $(LIBTRACEEVENT_FLAGS) O=$(OUTPUT) plugins
 
 $(LIBTRACEEVENT_DYNAMIC_LIST): libtraceevent_plugins
@@ -610,21 +635,21 @@ $(LIBTRACEEVENT)-clean:
 install-traceevent-plugins: libtraceevent_plugins
 	$(Q)$(MAKE) -C $(TRACE_EVENT_DIR) $(LIBTRACEEVENT_FLAGS) O=$(OUTPUT) install_plugins
 
-$(LIBAPI): fixdep FORCE
+$(LIBAPI): FORCE
 	$(Q)$(MAKE) -C $(LIB_DIR) O=$(OUTPUT) $(OUTPUT)libapi.a
 
 $(LIBAPI)-clean:
 	$(call QUIET_CLEAN, libapi)
 	$(Q)$(MAKE) -C $(LIB_DIR) O=$(OUTPUT) clean >/dev/null
 
-$(LIBBPF): fixdep FORCE
+$(LIBBPF): FORCE
 	$(Q)$(MAKE) -C $(BPF_DIR) O=$(OUTPUT) $(OUTPUT)libbpf.a FEATURES_DUMP=$(FEATURE_DUMP_EXPORT)
 
 $(LIBBPF)-clean:
 	$(call QUIET_CLEAN, libbpf)
 	$(Q)$(MAKE) -C $(BPF_DIR) O=$(OUTPUT) clean >/dev/null
 
-$(LIBSUBCMD): fixdep FORCE
+$(LIBSUBCMD): FORCE
 	$(Q)$(MAKE) -C $(SUBCMD_DIR) O=$(OUTPUT) $(OUTPUT)libsubcmd.a
 
 $(LIBSUBCMD)-clean:
@@ -832,3 +857,4 @@ FORCE:
 .PHONY: $(GIT-HEAD-PHONY) TAGS tags cscope FORCE prepare
 .PHONY: libtraceevent_plugins archheaders
 
+endif # force_fixdep
-- 
2.7.4