[PATCH 5/7] 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.

Link: http://lkml.kernel.org/n/tip-b6wi5cssl8apu74o2kbfheag@xxxxxxxxxxxxxx
Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
---
 tools/perf/Makefile.perf | 54 +++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 42 insertions(+), 12 deletions(-)

diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index 112f4f7bb200..25d9d6653746 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -179,6 +179,27 @@ 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 := $(config)
+endif
+
+# Disable config, we are forcing fixdep rule first
+# and it does not need config data.
+
+ifeq ($(force_fixdep),1)
+  config := 0
+endif
+
 # 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
@@ -324,10 +345,22 @@ LIBS = -Wl,--whole-archive $(PERFLIBS) -Wl,--no-whole-archive -Wl,--start-group
 
 export INSTALL SHELL_PATH
 
+export srctree OUTPUT RM CC LD AR CFLAGS V BISON FLEX AWK
+export HOSTCC HOSTLD HOSTAR
+include $(srctree)/tools/build/Makefile.include
+
 ### Build rules
 
 SHELL = $(SHELL_PATH)
 
+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
 all: shell_compatibility_test $(ALL_PROGRAMS) $(LANG_BINDINGS) $(OTHER_PROGRAMS)
 
 $(OUTPUT)python/perf.so: $(PYTHON_EXT_SRCS) $(PYTHON_EXT_DEPS) $(LIBTRACEEVENT_DYNAMIC_LIST)
@@ -348,10 +381,6 @@ strip: $(PROGRAMS) $(OUTPUT)perf
 
 PERF_IN := $(OUTPUT)perf-in.o
 
-export srctree OUTPUT RM CC LD AR CFLAGS 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
 
@@ -470,7 +499,7 @@ $(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)
@@ -515,7 +544,7 @@ 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) $@
@@ -565,7 +594,7 @@ $(patsubst perf-%,%.o,$(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)
@@ -573,10 +602,10 @@ $(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
@@ -589,21 +618,21 @@ $(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:
@@ -811,3 +840,4 @@ FORCE:
 .PHONY: $(GIT-HEAD-PHONY) TAGS tags cscope FORCE prepare
 .PHONY: libtraceevent_plugins archheaders
 
+endif # force_fixdep
-- 
2.7.4