--- a/Makefile.in
+++ b/Makefile.in
@@ -146,25 +146,22 @@ ifneq (,$(filter FasterMake+RecursiveMak
 install-manifests: faster
 .PHONY: faster
 faster: install-dist/idl
 	$(MAKE) -C faster FASTER_RECURSIVE_MAKE=1
 endif
 
 .PHONY: tup
 tup:
-	$(call BUILDSTATUS,TIERS $(if $(MOZ_ARTIFACT_BUILDS),artifact )make tup)
+	$(call BUILDSTATUS,TIERS $(if $(MOZ_ARTIFACT_BUILDS),artifact )tup)
 ifdef MOZ_ARTIFACT_BUILDS
 	$(call BUILDSTATUS,TIER_START artifact)
 	$(MAKE) recurse_artifact
 	$(call BUILDSTATUS,TIER_FINISH artifact)
 endif
-	$(call BUILDSTATUS,TIER_START make)
-	$(MAKE) buildid.h source-repo.h
-	$(call BUILDSTATUS,TIER_FINISH make)
 	$(call BUILDSTATUS,TIER_START tup)
 	@$(TUP) $(if $(findstring s,$(filter-out --%,$(MAKEFLAGS))),,--verbose)
 	$(call BUILDSTATUS,TIER_FINISH tup)
 
 .PHONY: $(addprefix install-,$(install_manifests))
 $(addprefix install-,$(install_manifests)): install-%: $(install_manifest_depends)
 ifneq (,$(filter FasterMake+RecursiveMake,$(BUILD_BACKENDS)))
 	@# If we're using the hybrid FasterMake/RecursiveMake backend, we want

--- a/python/mozbuild/mozbuild/backend/tup.py
+++ b/python/mozbuild/mozbuild/backend/tup.py
@@ -183,16 +183,20 @@ class TupOnly(CommonBackend, PartialBack
             '*.py',
             '*.rs',
         )
 
         # These are 'group' dependencies - All rules that list these as an output
         # will be built before any rules that list this as an input.
         self._installed_idls = '$(MOZ_OBJ_ROOT)/<installed-idls>'
         self._installed_files = '$(MOZ_OBJ_ROOT)/<installed-files>'
+        # The preprocessor including source-repo.h and buildid.h creates
+        # dependencies that aren't specified by moz.build and cause errors
+        # in Tup. Express these as a group dependency.
+        self._early_generated_files = '$(MOZ_OBJ_ROOT)/<early-generated-files>'
 
     def _get_backend_file(self, relobjdir):
         objdir = mozpath.normpath(mozpath.join(self.environment.topobjdir, relobjdir))
         if objdir not in self._backend_files:
             self._backend_files[objdir] = \
                     BackendTupfile(objdir, self.environment,
                                    self.environment.topsrcdir, self.environment.topobjdir)
         return self._backend_files[objdir]
@@ -216,24 +220,20 @@ class TupOnly(CommonBackend, PartialBack
 
         consumed = CommonBackend.consume_object(self, obj)
         if consumed:
             return True
 
         backend_file = self._get_backend_file_for(obj)
 
         if isinstance(obj, GeneratedFile):
-            # These files are already generated by make before tup runs.
-            skip_files = (
-                'buildid.h',
-                'source-repo.h',
-            )
+            skip_files = []
 
             if self.environment.is_artifact_build:
-                skip_files = skip_files + self._compile_env_gen_files
+                skip_files = self._compile_env_gen_files
 
             for f in obj.outputs:
                 if any(mozpath.match(f, p) for p in skip_files):
                     return False
 
             if 'application.ini.h' in obj.outputs:
                 # application.ini.h is a special case since we need to process
                 # the FINAL_TARGET_PP_FILES for application.ini before running
@@ -266,16 +266,22 @@ class TupOnly(CommonBackend, PartialBack
             self._process_computed_flags(obj, backend_file)
         elif isinstance(obj, (Sources, GeneratedSources)):
             backend_file.sources[obj.canonical_suffix].extend(obj.files)
         elif isinstance(obj, HostSources):
             backend_file.host_sources[obj.canonical_suffix].extend(obj.files)
         elif isinstance(obj, VariablePassthru):
             backend_file.variables = obj.variables
 
+        # The top-level Makefile.in still contains our driver target and some
+        # things related to artifact builds, so as a special case ensure the
+        # make backend generates a Makefile there.
+        if obj.objdir == self.environment.topobjdir:
+            return False
+
         return True
 
     def consume_finished(self):
         CommonBackend.consume_finished(self)
 
         # The approach here is similar to fastermake.py, but we
         # simply write out the resulting files here.
         for target, entries in self._manifest_entries.iteritems():
@@ -342,17 +348,21 @@ class TupOnly(CommonBackend, PartialBack
             full_inputs = [f.full_path for f in obj.inputs]
             cmd.extend(full_inputs)
             cmd.extend(shell_quote(f) for f in obj.flags)
 
             outputs = []
             outputs.extend(obj.outputs)
             outputs.append('%s.pp' % obj.outputs[0])
 
-            extra_outputs = [self._installed_files] if obj.required_for_compile else None
+            if any(f in obj.outputs for f in ('source-repo.h', 'buildid.h')):
+                extra_outputs = [self._early_generated_files]
+            else:
+                extra_outputs = [self._installed_files] if obj.required_for_compile else []
+                full_inputs += [self._early_generated_files]
 
             backend_file.rule(
                 display='python {script}:{method} -> [%o]'.format(script=obj.script, method=obj.method),
                 cmd=cmd,
                 inputs=full_inputs,
                 outputs=outputs,
                 extra_outputs=extra_outputs,
             )
@@ -509,16 +519,17 @@ class TupOnly(CommonBackend, PartialBack
 
         base_input = mozpath.basename(target)
         if base_input.endswith('.in'):
             base_input = mozpath.splitext(base_input)[0]
         output = mozpath.join(destdir, base_input) if destdir else base_input
 
         backend_file.rule(
             inputs=[input_file],
+            extra_inputs=[self._early_generated_files],
             display='Preprocess %o',
             cmd=cmd,
             outputs=[output],
         )
 
     def _handle_ipdl_sources(self, ipdl_dir, sorted_ipdl_sources, sorted_nonstatic_ipdl_sources,
                              sorted_static_ipdl_sources, unified_ipdl_cppsrcs_mapping):
         # Preferably we wouldn't have to import ipdl, but we need to parse the