Bug 1412932 - Switch to PGO build in Makefile.in; r=ted

Previously, client.mk made the decision of whether to perform a PGO
build. This required passing around MOZ_PGO and invoking a separate
make target if this variable was set.

In this commit, we move this logic to Makefile.in. We employ a special
mechanism in rules.mk to override the default make target so
`make` evaluates "profiledbuild" if MOZ_PGO is set. This also
required using an explicit target for $(MAKE) invocations inside
the "profiledbuild" rule to avoid infinite recursion.

MozReview-Commit-ID: 8sHiVspMisM

--HG--
extra : rebase_source : 76c8a0c592015802f2b9ad52fe2001012a4611f6
extra : source : 24e28b37fbc0ad55ee449699e09c62042af41b55

Makefile.in

@@ -226,22 +226,27 @@ default all::
 profiledbuild::
 	$(call BUILDSTATUS,TIERS pgo_profile_generate pgo_package pgo_profile pgo_clobber pgo_profile_use)
 	$(call BUILDSTATUS,TIER_START pgo_profile_generate)
-	$(MAKE) MOZ_PROFILE_GENERATE=1 MOZ_PGO_INSTRUMENTED=1
+	$(MAKE) default MOZ_PROFILE_GENERATE=1 MOZ_PGO_INSTRUMENTED=1
 	$(call BUILDSTATUS,TIER_FINISH pgo_profile_generate)
 	$(call BUILDSTATUS,TIER_START pgo_package)
 	$(MAKE) package MOZ_PGO_INSTRUMENTED=1 MOZ_INTERNAL_SIGNING_FORMAT= MOZ_EXTERNAL_SIGNING_FORMAT=
 	rm -f jarlog/en-US.log
 	$(call BUILDSTATUS,TIER_FINISH pgo_package)
 	$(call BUILDSTATUS,TIER_START pgo_profile)
-	MOZ_PGO_INSTRUMENTED=1 JARLOG_FILE=jarlog/en-US.log EXTRA_TEST_ARGS=10 $(MAKE) pgo-profile-run
+	$(MAKE) pgo-profile-run MOZ_PGO_INSTRUMENTED=1 JARLOG_FILE=jarlog/en-US.log EXTRA_TEST_ARGS=10
 	$(call BUILDSTATUS,TIER_FINISH pgo_profile)
 	$(call BUILDSTATUS,TIER_START pgo_clobber)
 	$(MAKE) maybe_clobber_profiledbuild
 	$(call BUILDSTATUS,TIER_FINISH pgo_clobber)
 	$(call BUILDSTATUS,TIER_START pgo_profile_use)
-	$(MAKE) MOZ_PROFILE_USE=1
+	$(MAKE) default MOZ_PROFILE_USE=1
 	$(call BUILDSTATUS,TIER_FINISH pgo_profile_use)
 
+# Change default target to PGO build if PGO is enabled.
+ifdef MOZ_PGO
+OVERRIDE_DEFAULT_GOAL := profiledbuild
+endif
+
 include $(topsrcdir)/config/rules.mk
 
 ifdef SCCACHE_VERBOSE_STATS

client.mk

@@ -86,8 +86,7 @@ endef
 # before evaluation. $(shell) replacing newlines with spaces, || is always
 # followed by a space (since sed doesn't remove newlines), except on the
 # last line, so replace both '|| ' and '||'.
-# Also, make MOZ_PGO available to mozconfig when passed on make command line.
-MOZCONFIG_CONTENT := $(subst ||,$(CR),$(subst || ,$(CR),$(shell MOZ_PGO=$(MOZ_PGO) $(TOPSRCDIR)/mach environment --format=client.mk | sed 's/$$/||/')))
+MOZCONFIG_CONTENT := $(subst ||,$(CR),$(subst || ,$(CR),$(shell $(TOPSRCDIR)/mach environment --format=client.mk | sed 's/$$/||/')))
 $(eval $(MOZCONFIG_CONTENT))
 
 export FOUND_MOZCONFIG
@@ -104,9 +103,6 @@ MOZCONFIG_OUT_FILTERED := $(filter-out $(START_COMMENT)%,$(MOZCONFIG_OUT_LINES))
 ifdef AUTOCLOBBER
 export AUTOCLOBBER=1
 endif
-ifdef MOZ_PGO
-export MOZ_PGO
-endif
 
 ifdef MOZ_PARALLEL_BUILD
   MOZ_MAKE_FLAGS := $(filter-out -j%,$(MOZ_MAKE_FLAGS))
@@ -290,7 +286,7 @@ endif
 # Build it
 
 build::  $(OBJDIR)/Makefile $(OBJDIR)/config.status
-	+$(MOZ_MAKE) $(if $(MOZ_PGO),profiledbuild)
+	+$(MOZ_MAKE)
 
 ####################################
 # Other targets

python/mozbuild/mozbuild/test/backend/test_build.py

@@ -34,6 +34,7 @@ class TestBuild(unittest.TestCase):
         self._old_env = dict(os.environ)
         os.environ.pop('MOZCONFIG', None)
         os.environ.pop('MOZ_OBJDIR', None)
+        os.environ.pop('MOZ_PGO', None)
 
     def tearDown(self):
         os.environ.clear()