diff -r 000000000000 -r 6474c204b198 config/recurse.mk
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/config/recurse.mk	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,219 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this file,
+# You can obtain one at http://mozilla.org/MPL/2.0/.
+
+ifndef INCLUDED_RULES_MK
+include $(topsrcdir)/config/rules.mk
+endif
+
+# The traditional model of directory traversal with make is as follows:
+#   make -C foo
+#     Entering foo
+#     make -C bar
+#       Entering foo/bar
+#     make -C baz
+#       Entering foo/baz
+#   make -C qux
+#     Entering qux
+#
+# Pseudo derecurse transforms the above into:
+#   make -C foo
+#   make -C foo/bar
+#   make -C foo/baz
+#   make -C qux
+
+# MOZ_PSEUDO_DERECURSE can have values other than 1.
+ifeq (1_.,$(if $(MOZ_PSEUDO_DERECURSE),1)_$(DEPTH))
+
+include root.mk
+
+# Disable build status for mach in top directories without TIERS.
+# In practice this disables it when recursing under js/src, which confuses mach.
+ifndef TIERS
+BUILDSTATUS =
+endif
+
+# Main rules (export, compile, binaries, libs and tools) call recurse_* rules.
+# This wrapping is only really useful for build status.
+compile binaries libs export tools::
+	$(call BUILDSTATUS,TIER_START $@)
+	+$(MAKE) recurse_$@
+	$(call BUILDSTATUS,TIER_FINISH $@)
+
+# Carefully avoid $(eval) type of rule generation, which makes pymake slower
+# than necessary.
+# Get current tier and corresponding subtiers from the data in root.mk.
+CURRENT_TIER := $(filter $(foreach tier,compile binaries libs export tools,recurse_$(tier) $(tier)-deps),$(MAKECMDGOALS))
+ifneq (,$(filter-out 0 1,$(words $(CURRENT_TIER))))
+$(error $(CURRENT_TIER) not supported on the same make command line)
+endif
+CURRENT_TIER := $(subst recurse_,,$(CURRENT_TIER:-deps=))
+CURRENT_SUBTIERS := $($(CURRENT_TIER)_subtiers)
+
+# The rules here are doing directory traversal, so we don't want further
+# recursion to happen when running make -C subdir $tier. But some make files
+# further call make -C something else, and sometimes expect recursion to
+# happen in that case (see browser/metro/locales/Makefile.in for example).
+# Conveniently, every invocation of make increases MAKELEVEL, so only stop
+# recursion from happening at current MAKELEVEL + 1.
+ifdef CURRENT_TIER
+ifeq (0,$(MAKELEVEL))
+export NO_RECURSE_MAKELEVEL=1
+else
+export NO_RECURSE_MAKELEVEL=$(word $(MAKELEVEL),2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20)
+endif
+endif
+
+# Get all directories traversed for all subtiers in the current tier, or use
+# directly the $(*_dirs) variables available in root.mk when there is no
+# TIERS (like for js/src).
+TIER_DIRS = $(or $($(1)_dirs),$(foreach subtier,$($(1)_subtiers),$($(1)_subtier_$(subtier))))
+CURRENT_DIRS := $(call TIER_DIRS,$(CURRENT_TIER))
+
+ifneq (,$(filter binaries libs,$(CURRENT_TIER)))
+WANT_STAMPS = 1
+STAMP_TOUCH = $(TOUCH) $(@D)/binaries
+endif
+
+# Subtier delimiter rules
+$(addprefix subtiers/,$(addsuffix _start/$(CURRENT_TIER),$(CURRENT_SUBTIERS))): subtiers/%_start/$(CURRENT_TIER): $(if $(WANT_STAMPS),$(call mkdir_deps,subtiers/%_start))
+	@$(STAMP_TOUCH)
+
+$(addprefix subtiers/,$(addsuffix _finish/$(CURRENT_TIER),$(CURRENT_SUBTIERS))): subtiers/%_finish/$(CURRENT_TIER): $(if $(WANT_STAMPS),$(call mkdir_deps,subtiers/%_finish))
+	@$(STAMP_TOUCH)
+
+$(addprefix subtiers/,$(addsuffix /$(CURRENT_TIER),$(CURRENT_SUBTIERS))): %/$(CURRENT_TIER): $(if $(WANT_STAMPS),$(call mkdir_deps,%))
+	@$(STAMP_TOUCH)
+
+GARBAGE_DIRS += subtiers
+
+# Recursion rule for all directories traversed for all subtiers in the
+# current tier.
+# root.mk defines subtier_of_* variables, that map a normalized subdir path to
+# a subtier name (e.g. subtier_of_memory_jemalloc = base)
+$(addsuffix /$(CURRENT_TIER),$(CURRENT_DIRS)): %/$(CURRENT_TIER):
+	+@$(MAKE) -C $* $(if $(filter $*,$(tier_$(subtier_of_$(subst /,_,$*))_staticdirs)),,$(CURRENT_TIER))
+# Ensure existing stamps are up-to-date, but don't create one if submake didn't create one.
+	$(if $(wildcard $@),@$(STAMP_TOUCH))
+
+# Dummy rules for possibly inexisting dependencies for the above tier targets
+$(addsuffix /Makefile,$(CURRENT_DIRS)) $(addsuffix /backend.mk,$(CURRENT_DIRS)):
+
+# The export tier requires nsinstall, which is built from config. So every
+# subdirectory traversal needs to happen after traversing config.
+ifeq ($(CURRENT_TIER),export)
+$(addsuffix /$(CURRENT_TIER),$(filter-out config,$(CURRENT_DIRS))): config/$(CURRENT_TIER)
+endif
+
+ifdef COMPILE_ENVIRONMENT
+ifneq (,$(filter libs binaries,$(CURRENT_TIER)))
+# When doing a "libs" build, target_libs.mk ensures the interesting dependency data
+# is available in the "binaries" stamp. Once recursion is done, aggregate all that
+# dependency info so that stamps depend on relevant files and relevant other stamps.
+# When doing a "binaries" build, the aggregate dependency file and those stamps are
+# used and allow to skip recursing directories where changes are not going to require
+# rebuild. A few directories, however, are still traversed all the time, mostly, the
+# gyp managed ones and js/src.
+# A few things that are not traversed by a "binaries" build, but should, in an ideal
+# world, are nspr, nss, icu and ffi.
+recurse_$(CURRENT_TIER):
+	@$(MAKE) binaries-deps
+
+# Creating binaries-deps.mk directly would make us build it twice: once when beginning
+# the build because of the include, and once at the end because of the stamps.
+binaries-deps: $(addsuffix /binaries,$(CURRENT_DIRS))
+	@$(call py_action,link_deps,-o $@.mk --group-by-depfile --topsrcdir $(topsrcdir) --topobjdir $(DEPTH) --dist $(DIST) --guard $(addprefix ',$(addsuffix ',$^)))
+	@$(TOUCH) $@
+
+ifeq (recurse_binaries,$(MAKECMDGOALS))
+$(call include_deps,binaries-deps.mk)
+endif
+
+endif
+
+DIST_GARBAGE += binaries-deps.mk binaries-deps
+
+endif
+
+else
+
+# Don't recurse if MAKELEVEL is NO_RECURSE_MAKELEVEL as defined above
+ifeq ($(NO_RECURSE_MAKELEVEL),$(MAKELEVEL))
+
+compile binaries libs export tools::
+
+else
+#########################
+# Tier traversal handling
+#########################
+
+ifdef TIERS
+
+libs export tools::
+	$(call BUILDSTATUS,TIER_START $@)
+	$(foreach tier,$(TIERS), $(if $(filter-out libs_precompile tools_precompile,$@_$(tier)), \
+		$(if $(filter libs,$@),$(foreach dir, $(tier_$(tier)_staticdirs), $(call TIER_DIR_SUBMAKE,$@,$(tier),$(dir),,1))) \
+		$(foreach dir, $(tier_$(tier)_dirs), $(call TIER_DIR_SUBMAKE,$@,$(tier),$(dir),$@))))
+	$(call BUILDSTATUS,TIER_FINISH $@)
+
+else
+
+define CREATE_SUBTIER_TRAVERSAL_RULE
+PARALLEL_DIRS_$(1) = $$(addsuffix _$(1),$$(PARALLEL_DIRS))
+
+.PHONY: $(1) $$(PARALLEL_DIRS_$(1))
+
+ifdef PARALLEL_DIRS
+$$(PARALLEL_DIRS_$(1)): %_$(1): %/Makefile
+	+@$$(call SUBMAKE,$(1),$$*)
+endif
+
+$(1):: $$(SUBMAKEFILES)
+ifdef PARALLEL_DIRS
+	+@$(MAKE) $$(PARALLEL_DIRS_$(1))
+endif
+	$$(LOOP_OVER_DIRS)
+
+endef
+
+$(foreach subtier,export compile binaries libs tools,$(eval $(call CREATE_SUBTIER_TRAVERSAL_RULE,$(subtier))))
+
+tools export:: $(SUBMAKEFILES)
+	$(LOOP_OVER_TOOL_DIRS)
+
+endif # ifdef TIERS
+
+endif # ifeq ($(NO_RECURSE_MAKELEVEL),$(MAKELEVEL))
+
+endif # ifeq (1_.,$(MOZ_PSEUDO_DERECURSE)_$(DEPTH))
+
+ifdef MOZ_PSEUDO_DERECURSE
+
+ifdef COMPILE_ENVIRONMENT
+
+# Aggregate all dependency files relevant to a binaries build except in
+# the mozilla top-level directory.
+ifneq (.,$(DEPTH))
+ALL_DEP_FILES := \
+  $(BINARIES_PP) \
+  $(addsuffix .pp,$(addprefix $(MDDEPDIR)/,$(sort \
+    $(TARGETS) \
+    $(filter-out $(SOBJS) $(ASOBJS) $(EXCLUDED_OBJS),$(OBJ_TARGETS)) \
+  ))) \
+  $(NULL)
+endif
+
+binaries libs:: $(TARGETS) $(BINARIES_PP)
+ifneq (.,$(DEPTH))
+	@$(if $^,$(call py_action,link_deps,-o binaries --group-all --topsrcdir $(topsrcdir) --topobjdir $(DEPTH) --dist $(DIST) $(ALL_DEP_FILES)))
+endif
+
+endif
+
+endif # ifdef MOZ_PSEUDO_DERECURSE
+
+recurse:
+	@$(RECURSED_COMMAND)
+	$(LOOP_OVER_PARALLEL_DIRS)
+	$(LOOP_OVER_DIRS)
+	$(LOOP_OVER_TOOL_DIRS)