perf tools: Force fixdep compilation at the start of the build

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.

Committer notes:

Testing it:

Before:

  $ rm -rf /tmp/build/perf/ ; mkdir -p /tmp/build/perf ; make -k O=/tmp/build/perf -C tools/perf install-bin
  make: Entering directory '/home/acme/git/linux/tools/perf'
    BUILD:   Doing 'make -j4' parallel build

  Auto-detecting system features:
  ...                         dwarf: [ on  ]
  ...            dwarf_getlocations: [ on  ]
  ...                         glibc: [ on  ]
  ...                          gtk2: [ on  ]
  ...                      libaudit: [ on  ]
  ...                        libbfd: [ on  ]
  ...                        libelf: [ on  ]
  ...                       libnuma: [ on  ]
  ...        numa_num_possible_cpus: [ on  ]
  ...                       libperl: [ on  ]
  ...                     libpython: [ on  ]
  ...                      libslang: [ on  ]
  ...                     libcrypto: [ on  ]
  ...                     libunwind: [ on  ]
  ...            libdw-dwarf-unwind: [ on  ]
  ...                          zlib: [ on  ]
  ...                          lzma: [ on  ]
  ...                     get_cpuid: [ on  ]
  ...                           bpf: [ on  ]

    GEN      /tmp/build/perf/common-cmds.h
    HOSTCC   /tmp/build/perf/fixdep.o
    HOSTLD   /tmp/build/perf/fixdep-in.o
    LINK     /tmp/build/perf/fixdep
    MKDIR    /tmp/build/perf/pmu-events/
    HOSTCC   /tmp/build/perf/pmu-events/json.o
    MKDIR    /tmp/build/perf/pmu-events/
    HOSTCC   /tmp/build/perf/pmu-events/jsmn.o
    HOSTCC   /tmp/build/perf/pmu-events/jevents.o
    HOSTLD   /tmp/build/perf/pmu-events/jevents-in.o
    PERF_VERSION = 4.9.rc8.g868cd5
    CC       /tmp/build/perf/perf-read-vdso32
  <SNIP>

After:

  $ rm -rf /tmp/build/perf/ ; mkdir -p /tmp/build/perf ; make -k O=/tmp/build/perf -C tools/perf install-bin
  make: Entering directory '/home/acme/git/linux/tools/perf'
    BUILD:   Doing 'make -j4' parallel build
    HOSTCC   /tmp/build/perf/fixdep.o
    HOSTLD   /tmp/build/perf/fixdep-in.o
    LINK     /tmp/build/perf/fixdep

  Auto-detecting system features:
  ...                         dwarf: [ on  ]
  ...            dwarf_getlocations: [ on  ]
  ...                         glibc: [ on  ]
  ...                          gtk2: [ on  ]
  ...                      libaudit: [ on  ]
  ...                        libbfd: [ on  ]
  ...                        libelf: [ on  ]
  ...                       libnuma: [ on  ]
  ...        numa_num_possible_cpus: [ on  ]
  ...                       libperl: [ on  ]
  ...                     libpython: [ on  ]
  ...                      libslang: [ on  ]
  ...                     libcrypto: [ on  ]
  ...                     libunwind: [ on  ]
  ...            libdw-dwarf-unwind: [ on  ]
  ...                          zlib: [ on  ]
  ...                          lzma: [ on  ]
  ...                     get_cpuid: [ on  ]
  ...                           bpf: [ on  ]

    GEN      /tmp/build/perf/common-cmds.h
    MKDIR    /tmp/build/perf/fd/
    CC       /tmp/build/perf/fd/array.o
    LD       /tmp/build/perf/fd/libapi-in.o
    MKDIR    /tmp/build/perf/fs/
    CC       /tmp/build/perf/event-parse.o
    CC       /tmp/build/perf/fs/fs.o
    PERF_VERSION = 4.9.rc8.g57a92f
    CC       /tmp/build/perf/event-plugin.o
    MKDIR    /tmp/build/perf/fs/
    CC       /tmp/build/perf/fs/tracing_path.o
  <SNIP>

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1481030331-31944-3-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

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