Bug 905879 - More robust tier tracking; r=glandium

Makefile.in

@@ -94,6 +94,9 @@ ifdef ENABLE_TESTS
 include $(topsrcdir)/testing/testsuite-targets.mk
 endif
 
+# Hacky way for precompile tier to bypass default tier traversal mechanism.
+TIER_precompile_CUSTOM := 1
+
 include $(topsrcdir)/config/rules.mk
 
 distclean::

config/makefiles/precompile/Makefile.in

@@ -24,10 +24,12 @@ $(call BUILDSTATUS,SUBTIER_FINISH precompile $(1))
 
 endef
 
-export::
+default::
-	$(call BUILDSTATUS,SUBTIERS IPDL WebIDL XPIDL XPIDLParser)
+	$(call BUILDSTATUS,TIER_START  precompile IPDL WebIDL XPIDL)
+	+$(MAKE) export
+	$(call BUILDSTATUS,TIER_FINISH precompile)
 
-export:: ipdl webidl xpidl-parser xpidl
+export:: ipdl webidl xpidl
 
 ipdl:
 	$(call make_subtier_dir,IPDL,$(DEPTH)/ipc/ipdl,ipdl)
@@ -35,9 +37,9 @@ ipdl:
 webidl:
 	$(call make_subtier_dir,WebIDL,$(DEPTH)/dom/bindings,webidl)
 
-xpidl-parser:
+xpidl:
-	$(call make_subtier_dir,XPIDLParser,$(DEPTH)/xpcom/idl-parser,xpidl-parser)
+	$(call BUILDSTATUS,SUBTIER_START  precompile XPIDL)
-
+	+$(MAKE) -C $(DEPTH)/xpcom/idl-parser xpidl-parser
-xpidl: xpidl-parser
 	$(call py_action,process_install_manifest,$(DIST)/idl $(DEPTH)/_build_manifests/install/dist_idl)
-	$(call make_subtier_dir,XPIDL,$(DEPTH)/config/makefiles/xpidl,xpidl)
+	+$(MAKE) -C $(DEPTH)/config/makefiles/xpidl xpidl
+	$(call BUILDSTATUS,SUBTIER_FINISH precompile XPIDL)

config/makefiles/target_export.mk

@@ -14,7 +14,7 @@ PARALLEL_DIRS_export = $(addsuffix _export,$(PARALLEL_DIRS))
 ###############
 $(addprefix export_tier_,$(TIERS)): export_tier_%:
 	@$(ECHO) "$@"
-	$(foreach dir,$(tier_$*_dirs),$(call TIER_DIR_SUBMAKE,export,$(dir)))
+	$(foreach dir,$(tier_$*_dirs),$(call TIER_DIR_SUBMAKE,$*,export,$(dir),export))
 
 #################
 ## Common targets

config/makefiles/target_libs.mk

@@ -14,7 +14,7 @@ PARALLEL_DIRS_libs = $(addsuffix _libs,$(PARALLEL_DIRS))
 ###############
 $(addprefix libs_tier_,$(TIERS)): libs_tier_%:
 	@$(ECHO) "$@"
-	$(foreach dir,$(tier_$*_dirs),$(call TIER_DIR_SUBMAKE,libs,$(dir)))
+	$(foreach dir,$(tier_$*_dirs),$(call TIER_DIR_SUBMAKE,$*,libs,$(dir),libs))
 
 #################
 ## Common targets

config/makefiles/target_tools.mk

@@ -14,7 +14,7 @@ PARALLEL_DIRS_tools = $(addsuffix _tools,$(PARALLEL_DIRS))
 ###############
 $(addprefix tools_tier_,$(TIERS)): tools_tier_%:
 	@$(ECHO) "$@"
-	$(foreach dir,$(tier_$*_dirs),$(call TIER_DIR_SUBMAKE,tools,$(dir)))
+	$(foreach dir,$(tier_$*_dirs),$(call TIER_DIR_SUBMAKE,$*,tools,$(dir),tools))
 
 #################
 ## Common targets

config/rules.mk

@@ -429,8 +429,9 @@ UPDATE_TITLE = printf "\033]0;%s in %s\007" $(1) $(shell $(BUILD_TOOLS)/print-de
 endif
 
 ifdef MACH
-BUILDSTATUS=@echo BUILDSTATUS $1
+BUILDSTATUS=@echo "BUILDSTATUS $1"
 endif
+
 # Static directories are largely independent of our build system. But, they
 # could share the same build mechanism (like moz.build files). We need to
 # prevent leaking of our backend state to these independent build systems. This
@@ -443,9 +444,9 @@ define SUBMAKE # $(call SUBMAKE,target,directory,static)
 endef # The extra line is important here! don't delete it
 
 define TIER_DIR_SUBMAKE
-$(call BUILDSTATUS,TIERDIR_START  $(2))
+$(call BUILDSTATUS,TIERDIR_START  $(1) $(2) $(3))
-$(call SUBMAKE,$(1),$(2),$(3))
+$(call SUBMAKE,$(4),$(3),$(5))
-$(call BUILDSTATUS,TIERDIR_FINISH $(2))
+$(call BUILDSTATUS,TIERDIR_FINISH $(1) $(2) $(3))
 
 endef # Ths empty line is important.
 
@@ -712,32 +713,38 @@ QUIET := -q
 endif
 
 # This function is called and evaluated to produce the rule to build the
-# specified tier. Each tier begins by building the "static" directories.
+# specified tier.
-# The BUILDSTATUS echo commands are used to faciliate easier parsing
+#
-# of build output. Build drivers are encouraged to filter these lines
+# Tiers are traditionally composed of directories that are invoked either
-# from the user.
+# once (so-called "static" directories) or 3 times with the export, libs, and
+# tools sub-tiers.
+#
+# If the TIER_$(tier)_CUSTOM variable is defined, then these traditional
+# tier rules are ignored and each directory in the tier is executed via a
+# sub-make invocation (make -C).
 define CREATE_TIER_RULE
 tier_$(1)::
-	$(call BUILDSTATUS,TIER_START $(1))
+ifdef TIER_$(1)_CUSTOM
-	$(call BUILDSTATUS,SUBTIERS $(if $(tier_$(1)_staticdirs),static )$(if $(tier_$(1)_dirs),export libs tools))
+	$$(foreach dir,$$($$@_dirs),$$(call SUBMAKE,,$$(dir)))
-	$(call BUILDSTATUS,STATICDIRS $$($$@_staticdirs))
+else
-	$(call BUILDSTATUS,DIRS $$($$@_dirs))
+	$(call BUILDSTATUS,TIER_START $(1) $(if $(tier_$(1)_staticdirs),static )$(if $(tier_$(1)_dirs),export libs tools))
 ifneq (,$(tier_$(1)_staticdirs))
-	$(call BUILDSTATUS,SUBTIER_START $(1) static)
+	$(call BUILDSTATUS,SUBTIER_START  $(1) static $$($$@_staticdirs))
-	$$(foreach dir,$$($$@_staticdirs),$$(call TIER_DIR_SUBMAKE,,$$(dir),1))
+	$$(foreach dir,$$($$@_staticdirs),$$(call TIER_DIR_SUBMAKE,$(1),static,$$(dir),,1))
 	$(call BUILDSTATUS,SUBTIER_FINISH $(1) static)
 endif
 ifneq (,$(tier_$(1)_dirs))
-	$(call BUILDSTATUS,SUBTIER_START $(1) export)
+	$(call BUILDSTATUS,SUBTIER_START  $(1) export $$($$@_dirs))
 	$$(MAKE) export_$$@
 	$(call BUILDSTATUS,SUBTIER_FINISH $(1) export)
-	$(call BUILDSTATUS,SUBTIER_START $(1) libs)
+	$(call BUILDSTATUS,SUBTIER_START  $(1) libs $$($$@_dirs))
 	$$(MAKE) libs_$$@
 	$(call BUILDSTATUS,SUBTIER_FINISH $(1) libs)
-	$(call BUILDSTATUS,SUBTIER_START $(1) tools)
+	$(call BUILDSTATUS,SUBTIER_START  $(1) tools $$($$@_dirs))
 	$$(MAKE) tools_$$@
 	$(call BUILDSTATUS,SUBTIER_FINISH $(1) tools)
-	$(call BUILDSTATUS TIER_FINISH $(1))
+endif
+	$(call BUILDSTATUS,TIER_FINISH $(1))
 endif
 endef
 

js/src/config/makefiles/target_export.mk

@@ -14,7 +14,7 @@ PARALLEL_DIRS_export = $(addsuffix _export,$(PARALLEL_DIRS))
 ###############
 $(addprefix export_tier_,$(TIERS)): export_tier_%:
 	@$(ECHO) "$@"
-	$(foreach dir,$(tier_$*_dirs),$(call TIER_DIR_SUBMAKE,export,$(dir)))
+	$(foreach dir,$(tier_$*_dirs),$(call TIER_DIR_SUBMAKE,$*,export,$(dir),export))
 
 #################
 ## Common targets

js/src/config/makefiles/target_libs.mk

@@ -14,7 +14,7 @@ PARALLEL_DIRS_libs = $(addsuffix _libs,$(PARALLEL_DIRS))
 ###############
 $(addprefix libs_tier_,$(TIERS)): libs_tier_%:
 	@$(ECHO) "$@"
-	$(foreach dir,$(tier_$*_dirs),$(call TIER_DIR_SUBMAKE,libs,$(dir)))
+	$(foreach dir,$(tier_$*_dirs),$(call TIER_DIR_SUBMAKE,$*,libs,$(dir),libs))
 
 #################
 ## Common targets

js/src/config/makefiles/target_tools.mk

@@ -14,7 +14,7 @@ PARALLEL_DIRS_tools = $(addsuffix _tools,$(PARALLEL_DIRS))
 ###############
 $(addprefix tools_tier_,$(TIERS)): tools_tier_%:
 	@$(ECHO) "$@"
-	$(foreach dir,$(tier_$*_dirs),$(call TIER_DIR_SUBMAKE,tools,$(dir)))
+	$(foreach dir,$(tier_$*_dirs),$(call TIER_DIR_SUBMAKE,$*,tools,$(dir),tools))
 
 #################
 ## Common targets

js/src/config/rules.mk

@@ -429,8 +429,9 @@ UPDATE_TITLE = printf "\033]0;%s in %s\007" $(1) $(shell $(BUILD_TOOLS)/print-de
 endif
 
 ifdef MACH
-BUILDSTATUS=@echo BUILDSTATUS $1
+BUILDSTATUS=@echo "BUILDSTATUS $1"
 endif
+
 # Static directories are largely independent of our build system. But, they
 # could share the same build mechanism (like moz.build files). We need to
 # prevent leaking of our backend state to these independent build systems. This
@@ -443,9 +444,9 @@ define SUBMAKE # $(call SUBMAKE,target,directory,static)
 endef # The extra line is important here! don't delete it
 
 define TIER_DIR_SUBMAKE
-$(call BUILDSTATUS,TIERDIR_START  $(2))
+$(call BUILDSTATUS,TIERDIR_START  $(1) $(2) $(3))
-$(call SUBMAKE,$(1),$(2),$(3))
+$(call SUBMAKE,$(4),$(3),$(5))
-$(call BUILDSTATUS,TIERDIR_FINISH $(2))
+$(call BUILDSTATUS,TIERDIR_FINISH $(1) $(2) $(3))
 
 endef # Ths empty line is important.
 
@@ -712,32 +713,38 @@ QUIET := -q
 endif
 
 # This function is called and evaluated to produce the rule to build the
-# specified tier. Each tier begins by building the "static" directories.
+# specified tier.
-# The BUILDSTATUS echo commands are used to faciliate easier parsing
+#
-# of build output. Build drivers are encouraged to filter these lines
+# Tiers are traditionally composed of directories that are invoked either
-# from the user.
+# once (so-called "static" directories) or 3 times with the export, libs, and
+# tools sub-tiers.
+#
+# If the TIER_$(tier)_CUSTOM variable is defined, then these traditional
+# tier rules are ignored and each directory in the tier is executed via a
+# sub-make invocation (make -C).
 define CREATE_TIER_RULE
 tier_$(1)::
-	$(call BUILDSTATUS,TIER_START $(1))
+ifdef TIER_$(1)_CUSTOM
-	$(call BUILDSTATUS,SUBTIERS $(if $(tier_$(1)_staticdirs),static )$(if $(tier_$(1)_dirs),export libs tools))
+	$$(foreach dir,$$($$@_dirs),$$(call SUBMAKE,,$$(dir)))
-	$(call BUILDSTATUS,STATICDIRS $$($$@_staticdirs))
+else
-	$(call BUILDSTATUS,DIRS $$($$@_dirs))
+	$(call BUILDSTATUS,TIER_START $(1) $(if $(tier_$(1)_staticdirs),static )$(if $(tier_$(1)_dirs),export libs tools))
 ifneq (,$(tier_$(1)_staticdirs))
-	$(call BUILDSTATUS,SUBTIER_START $(1) static)
+	$(call BUILDSTATUS,SUBTIER_START  $(1) static $$($$@_staticdirs))
-	$$(foreach dir,$$($$@_staticdirs),$$(call TIER_DIR_SUBMAKE,,$$(dir),1))
+	$$(foreach dir,$$($$@_staticdirs),$$(call TIER_DIR_SUBMAKE,$(1),static,$$(dir),,1))
 	$(call BUILDSTATUS,SUBTIER_FINISH $(1) static)
 endif
 ifneq (,$(tier_$(1)_dirs))
-	$(call BUILDSTATUS,SUBTIER_START $(1) export)
+	$(call BUILDSTATUS,SUBTIER_START  $(1) export $$($$@_dirs))
 	$$(MAKE) export_$$@
 	$(call BUILDSTATUS,SUBTIER_FINISH $(1) export)
-	$(call BUILDSTATUS,SUBTIER_START $(1) libs)
+	$(call BUILDSTATUS,SUBTIER_START  $(1) libs $$($$@_dirs))
 	$$(MAKE) libs_$$@
 	$(call BUILDSTATUS,SUBTIER_FINISH $(1) libs)
-	$(call BUILDSTATUS,SUBTIER_START $(1) tools)
+	$(call BUILDSTATUS,SUBTIER_START  $(1) tools $$($$@_dirs))
 	$$(MAKE) tools_$$@
 	$(call BUILDSTATUS,SUBTIER_FINISH $(1) tools)
-	$(call BUILDSTATUS TIER_FINISH $(1))
+endif
+	$(call BUILDSTATUS,TIER_FINISH $(1))
 endif
 endef
 

python/mozbuild/mozbuild/controller/building.py

@@ -9,7 +9,10 @@ import os
 import sys
 import time
 
-from collections import namedtuple
+from collections import (
+    namedtuple,
+    OrderedDict,
+)
 
 # keep in sync with psutil os support, see psutil/__init__.py
 if sys.platform.startswith("freebsd") or sys.platform.startswith("darwin") or sys.platform.startswith("win32") or sys.platform.startswith("linux"):
@@ -20,6 +23,8 @@ if sys.platform.startswith("freebsd") or sys.platform.startswith("darwin") or sy
 else:
     psutil = None
 
+from ..base import MozbuildObject
+
 from ..compilation.warnings import (
     WarningsCollector,
     WarningsDatabase,
@@ -30,27 +35,150 @@ BuildOutputResult = namedtuple('BuildOutputResult',
     ('warning', 'state_changed', 'for_display'))
 
 
-class BuildMonitor(object):
+class TierStatus(object):
+    """Represents the state and progress of tier traversal.
+
+    The build system is organized into linear phases called tiers. Each tier
+    executes in the order it was defined, 1 at a time.
+
+    Tiers can have subtiers. Subtiers can execute in any order. Some subtiers
+    execute sequentially. Others are concurrent.
+
+    Subtiers can have directories. Directories can execute in any order, just
+    like subtiers.
+    """
+
+    def __init__(self):
+        self.tiers = OrderedDict()
+        self.active_tier = None
+        self.active_subtiers = set()
+
+    def set_tiers(self, tiers):
+        """Record the set of known tiers."""
+        for tier in tiers:
+            self.tiers[tier] = dict(
+                begin_time=None,
+                finish_time=None,
+                duration=None,
+                subtiers=OrderedDict(),
+            )
+
+    def begin_tier(self, tier, subtiers):
+        """Record that execution of a tier has begun."""
+        t = self.tiers[tier]
+        # We should ideally use a monotonic clock here. Unfortunately, we won't
+        # have one until Python 3.
+        t['begin_time'] = time.time()
+        for subtier in subtiers:
+            t['subtiers'][subtier] = dict(
+                begin_time=None,
+                finish_time=None,
+                duration=None,
+                concurrent=False,
+                dirs=OrderedDict(),
+                dirs_complete=0,
+            )
+
+        self.active_tier = tier
+        self.active_subtiers = set()
+        self.active_dirs = {}
+
+    def finish_tier(self, tier):
+        """Record that execution of a tier has finished."""
+        t = self.tiers[tier]
+        t['finish_time'] = time.time()
+        t['duration'] = t['finish_time'] - t['begin_time']
+
+    def begin_subtier(self, tier, subtier, dirs):
+        """Record that execution of a subtier has begun."""
+        st = self.tiers[tier]['subtiers'][subtier]
+        st['begin_time'] = time.time()
+
+        for d in dirs:
+            st['dirs'][d] = dict(
+                begin_time=None,
+                finish_time=None,
+                duration=None,
+                concurrent=False,
+            )
+
+        if self.active_subtiers:
+            st['concurrent'] = True
+
+        self.active_subtiers.add(subtier)
+
+    def finish_subtier(self, tier, subtier):
+        """Record that execution of a subtier has finished."""
+        st = self.tiers[tier]['subtiers'][subtier]
+        st['finish_time'] = time.time()
+
+        self.active_subtiers.remove(subtier)
+        if self.active_subtiers:
+            st['concurrent'] = True
+
+        # A subtier may not have directories.
+        try:
+            del self.active_dirs[subtier]
+        except KeyError:
+            pass
+
+        st['duration'] = st['finish_time'] - st['begin_time']
+
+    def begin_dir(self, tier, subtier, d):
+        """Record that execution of a directory has begun."""
+        entry = self.tiers[tier]['subtiers'][subtier]['dirs'][d]
+        entry['begin_time'] = time.time()
+
+        self.active_dirs.setdefault(subtier, set()).add(d)
+
+        if len(self.active_dirs[subtier]) > 1:
+            entry['concurrent'] = True
+
+    def finish_dir(self, tier, subtier, d):
+        """Record that execution of a directory has finished."""
+        st = self.tiers[tier]['subtiers'][subtier]
+        st['dirs_complete'] += 1
+
+        entry = st['dirs'][d]
+        entry['finish_time'] = time.time()
+
+        self.active_dirs[subtier].remove(d)
+        entry['duration'] = entry['finish_time'] - entry['begin_time']
+
+        if self.active_dirs[subtier]:
+            entry['concurrent'] = True
+
+    def tier_status(self):
+        for tier, state in self.tiers.items():
+            active = self.active_tier == tier
+            finished = state['finish_time'] is not None
+
+            yield tier, active, finished
+
+    def current_subtier_status(self):
+        for subtier, state in self.tiers[self.active_tier]['subtiers'].items():
+            active = subtier in self.active_subtiers
+            finished = state['finish_time'] is not None
+
+            yield subtier, active, finished
+
+    def current_dirs_status(self):
+        for subtier, dirs in self.active_dirs.items():
+            st = self.tiers[self.active_tier]['subtiers'][subtier]
+            yield subtier, st['dirs'].keys(), dirs, st['dirs_complete']
+
+
+class BuildMonitor(MozbuildObject):
     """Monitors the output of the build."""
 
-    def __init__(self, topobjdir, warnings_path):
+    def init(self, warnings_path):
         """Create a new monitor.
 
         warnings_path is a path of a warnings database to use.
         """
         self._warnings_path = warnings_path
 
-        self.tiers = []
+        self.tiers = TierStatus()
-        self.subtiers = []
-        self.current_tier = None
-        self.current_subtier = None
-        self.current_tier_dirs = []
-        self.current_tier_static_dirs = []
-        self.current_subtier_dirs = []
-        self.current_subtier_started = set()
-        self.current_subtier_finished = set()
-        self.current_tier_dir = None
-        self.current_tier_dir_index = 0
 
         self.warnings_database = WarningsDatabase()
         if os.path.exists(warnings_path):
@@ -60,7 +188,7 @@ class BuildMonitor(object):
                 os.remove(warnings_path)
 
         self._warnings_collector = WarningsCollector(
-            database=self.warnings_database, objdir=topobjdir)
+            database=self.warnings_database, objdir=self.topobjdir)
 
     def start(self):
         """Record the start of the build."""
@@ -93,51 +221,28 @@ class BuildMonitor(object):
             update_needed = True
 
             if action == 'TIERS':
-                self.tiers = args
+                self.tiers.set_tiers(args)
-                update_needed = False
-            elif action == 'SUBTIERS':
-                self.subtiers = args
-                update_needed = False
-            elif action == 'STATICDIRS':
-                self.current_tier_static_dirs = args
-                update_needed = False
-            elif action == 'DIRS':
-                self.current_tier_dirs = args
                 update_needed = False
             elif action == 'TIER_START':
-                assert len(args) == 1
+                tier = args[0]
-                self.current_tier = args[0]
+                subtiers = args[1:]
-                self.current_subtier = None
+                self.tiers.begin_tier(tier, subtiers)
-                self.current_tier_dirs = []
-                self.current_subtier_started = set()
-                self.current_subtier_finished = set()
-                self.current_tier_dir = None
             elif action == 'TIER_FINISH':
-                assert len(args) == 1
+                tier, = args
-                assert args[0] == self.current_tier
+                self.tiers.finish_tier(tier)
             elif action == 'SUBTIER_START':
-                assert len(args) == 2
+                tier, subtier = args[0:2]
-                tier, subtier = args
+                dirs = args[2:]
-                assert tier == self.current_tier
+                self.tiers.begin_subtier(tier, subtier, dirs)
-                self.current_subtier = subtier
-                if subtier == 'static':
-                    self.current_subtier_dirs = self.current_tier_static_dirs
-                else:
-                    self.current_subtier_dirs = self.current_tier_dirs
-                self.current_tier_dir_index = 0
-                self.current_subtier_started.add(subtier)
             elif action == 'SUBTIER_FINISH':
-                assert len(args) == 2
                 tier, subtier = args
-                assert tier == self.current_tier
+                self.tiers.finish_subtier(tier, subtier)
-                self.current_subtier_finished.add(subtier)
             elif action == 'TIERDIR_START':
-                assert len(args) == 1
+                tier, subtier, d = args
-                self.current_tier_dir = args[0]
+                self.tiers.begin_dir(tier, subtier, d)
-                self.current_tier_dir_index += 1
             elif action == 'TIERDIR_FINISH':
-                assert len(args) == 1
+                tier, subtier, d = args
-                assert self.current_tier_dir == args[0]
+                self.tiers.finish_dir(tier, subtier, d)
             else:
                 raise Exception('Unknown build status: %s' % action)
 

python/mozbuild/mozbuild/mach_commands.py

@@ -113,7 +113,9 @@ class BuildProgressFooter(object):
 
     def draw(self):
         """Draws this footer in the terminal."""
-        if not self._monitor.tiers:
+        tiers = self._monitor.tiers
+
+        if not tiers.tiers:
             return
 
         # The drawn terminal looks something like:
@@ -124,34 +126,48 @@ class BuildProgressFooter(object):
         # big comment below.
         parts = [('bold', 'TIER'), ':', ' ']
 
-        current_encountered = False
+        for tier, active, finished in tiers.tier_status():
-        for tier in self._monitor.tiers:
+            if active:
-            if tier == self._monitor.current_tier:
                 parts.extend([('underline_yellow', tier), ' '])
-                current_encountered = True
+            elif finished:
-            elif not current_encountered:
                 parts.extend([('green', tier), ' '])
             else:
                 parts.extend([tier, ' '])
 
         parts.extend([('bold', 'SUBTIER'), ':', ' '])
-        for subtier in self._monitor.subtiers:
+        for subtier, active, finished in tiers.current_subtier_status():
-            if subtier in self._monitor.current_subtier_finished:
+            if active:
-                parts.extend([('green', subtier), ' '])
-            elif subtier in self._monitor.current_subtier_started:
                 parts.extend([('underline_yellow', subtier), ' '])
+            elif finished:
+                parts.extend([('green', subtier), ' '])
             else:
                 parts.extend([subtier, ' '])
 
-        if self._monitor.current_subtier_dirs and self._monitor.current_tier_dir:
+        if tiers.active_dirs:
+            parts.extend([('bold', 'DIRECTORIES'), ': '])
+            have_dirs = False
+
+            for subtier, all_dirs, active_dirs, complete in tiers.current_dirs_status():
+                if len(all_dirs) < 2:
+                    continue
+
+                have_dirs = True
+
                 parts.extend([
-                ('bold', 'DIRECTORIES'), ': ',
+                    '%02d' % (complete + 1),
-                '%02d' % self._monitor.current_tier_dir_index,
                     '/',
-                '%02d' % len(self._monitor.current_subtier_dirs),
+                    '%02d' % len(all_dirs),
                     ' ',
-                '(', ('magenta', self._monitor.current_tier_dir), ')',
+                    '(',
                 ])
+                for d in active_dirs:
+                    parts.extend([
+                        ('magenta', d), ' ,'
+                    ])
+                parts[-1] = ')'
+
+            if not have_dirs:
+                parts = parts[0:-2]
 
         # We don't want to write more characters than the current width of the
         # terminal otherwise wrapping may result in weird behavior. We can't
@@ -274,7 +290,8 @@ class Build(MachCommandBase):
         from mozbuild.util import resolve_target_to_make
 
         warnings_path = self._get_state_filename('warnings.json')
-        monitor = BuildMonitor(self.topobjdir, warnings_path)
+        monitor = self._spawn(BuildMonitor)
+        monitor.init(warnings_path)
 
         with BuildOutputManager(self.log_manager, monitor) as output:
             monitor.start()