--- a/python/mozbuild/mozbuild/backend/recursivemake.py
+++ b/python/mozbuild/mozbuild/backend/recursivemake.py
@@ -501,29 +501,30 @@ class RecursiveMakeBackend(CommonBackend
                 else:
                     backend_file.write('%s := %s\n' % (k, v))
         elif isinstance(obj, HostDefines):
             self._process_defines(obj, backend_file, which='HOST_DEFINES')
         elif isinstance(obj, Defines):
             self._process_defines(obj, backend_file)
 
         elif isinstance(obj, GeneratedFile):
-            self._no_skip['export'].add(backend_file.relobjdir)
+            tier = 'misc' if any(isinstance(f, ObjDirPath) for f in obj.inputs) else 'export'
+            self._no_skip[tier].add(backend_file.relobjdir)
             dep_file = "%s.pp" % obj.output
-            backend_file.write('export:: %s\n' % obj.output)
+            backend_file.write('%s:: %s\n' % (tier, obj.output))
             backend_file.write('GARBAGE += %s\n' % obj.output)
             backend_file.write('EXTRA_MDDEPEND_FILES += %s\n' % dep_file)
             if obj.script:
                 backend_file.write("""{output}: {script}{inputs}{backend}
 \t$(REPORT_BUILD)
 \t$(call py_action,file_generate,{script} {method} {output} $(MDDEPDIR)/{dep_file}{inputs}{flags})
 
 """.format(output=obj.output,
            dep_file=dep_file,
-           inputs=' ' + ' '.join(obj.inputs) if obj.inputs else '',
+           inputs=' ' + ' '.join([f.full_path for f in obj.inputs]) if obj.inputs else '',
            flags=' ' + ' '.join(obj.flags) if obj.flags else '',
            backend=' backend.mk' if obj.flags else '',
            script=obj.script,
            method=obj.method))
 
         elif isinstance(obj, JARManifest):
             self._no_skip['libs'].add(backend_file.relobjdir)
             backend_file.write('JAR_MANIFEST := %s\n' % obj.path.full_path)

--- a/python/mozbuild/mozbuild/frontend/emitter.py
+++ b/python/mozbuild/mozbuild/frontend/emitter.py
@@ -566,17 +566,17 @@ class TreeMetadataEmitter(LoggingMixin):
                     script = mozpath.join(
                         mozpath.dirname(mozpath.dirname(__file__)),
                         'action', 'generate_symbols_file.py')
                     defines = ()
                     if lib.defines:
                         defines = lib.defines.get_defines()
                     yield GeneratedFile(context, script,
                         'generate_symbols_file', lib.symbols_file,
-                        [symbols_file.full_path], defines)
+                        [symbols_file], defines)
             if static_lib:
                 lib = StaticLibrary(context, libname, **static_args)
                 self._libs[libname].append(lib)
                 self._linkage.append((context, lib, 'USE_LIBS'))
                 has_linkables = True
 
             if lib_defines:
                 if not libname:
@@ -976,17 +976,17 @@ class TreeMetadataEmitter(LoggingMixin):
                 xpidl_module, add_to_manifest=not context['XPIDL_NO_MANIFEST'])
 
     def _process_generated_files(self, context):
         for path in context['CONFIGURE_DEFINE_FILES']:
             script = mozpath.join(mozpath.dirname(mozpath.dirname(__file__)),
                                   'action', 'process_define_files.py')
             yield GeneratedFile(context, script, 'process_define_file',
                                 unicode(path),
-                                [mozpath.join(context.srcdir, path + '.in')])
+                                [Path(context, path + '.in')])
 
         generated_files = context.get('GENERATED_FILES')
         if not generated_files:
             return
 
         for f in generated_files:
             flags = generated_files[f]
             output = f
@@ -1011,17 +1011,17 @@ class TreeMetadataEmitter(LoggingMixin):
 
                 for i in flags.inputs:
                     p = Path(context, i)
                     if (isinstance(p, SourcePath) and
                             not os.path.exists(p.full_path)):
                         raise SandboxValidationError(
                             'Input for generating %s does not exist: %s'
                             % (f, p.full_path), context)
-                    inputs.append(p.full_path)
+                    inputs.append(p)
             else:
                 script = None
                 method = None
             yield GeneratedFile(context, script, method, output, inputs)
 
     def _process_test_manifests(self, context):
         for prefix, info in TEST_MANIFESTS.items():
             for path, manifest in context.get('%s_MANIFESTS' % prefix, []):