--- a/accessible/mac/moz.build
+++ b/accessible/mac/moz.build
@@ -42,22 +42,18 @@ LOCAL_INCLUDES += [
     '/accessible/ipc/other',
     '/accessible/xul',
     '/layout/generic',
     '/layout/xul',
     '/widget',
     '/widget/cocoa',
 ]
 
-GENERATED_FILES += [
-    'MacSelectorMap.h',
-    'MacSelectorMap.mm',
-]
-
-GENERATED_FILES['MacSelectorMap.mm'].script = '/accessible/mac/SelectorMapGen.py:gen_mm'
-GENERATED_FILES['MacSelectorMap.mm'].inputs = ['MOXAccessibleProtocol.h']
-
-GENERATED_FILES['MacSelectorMap.h'].script = '/accessible/mac/SelectorMapGen.py:gen_h'
-GENERATED_FILES['MacSelectorMap.h'].inputs = ['MOXAccessibleProtocol.h']
+GeneratedFile('MacSelectorMap.h',
+              script='/accessible/mac/SelectorMapGen.py', entry_point='gen_h',
+              inputs=['MOXAccessibleProtocol.h'])
+GeneratedFile('MacSelectorMap.mm',
+              script='/accessible/mac/SelectorMapGen.py', entry_point='gen_mm',
+              inputs=['MOXAccessibleProtocol.h'])
 
 FINAL_LIBRARY = 'xul'
 
 include('/ipc/chromium/chromium-config.mozbuild')

--- a/config/moz.build
+++ b/config/moz.build
@@ -50,21 +50,19 @@ if CONFIG['WRAP_STL_INCLUDES']:
         # GeneratedFile.__init__ in python/mozbuild/mozbuild/frontend/data.py
         # might need to be updated accordingly as well.
         template_file = SRCDIR + '/%s-stl-wrapper.template.h' % stl_compiler
         output_dir = '../dist/stl_wrappers'
         # We have to use a sentinel file as the first file because the
         # file_generate action will create it for us, but we want to create all
         # the files in gen_wrappers()
         outputs = tuple(['stl.sentinel'] + ['%s/%s' % (output_dir, h) for h in stl_headers])
-        GENERATED_FILES += [outputs]
-        stl = GENERATED_FILES[outputs]
-        stl.script = 'make-stl-wrappers.py:gen_wrappers'
-        stl.flags = [output_dir, stl_compiler, template_file]
-        stl.flags.extend(stl_headers)
+        GeneratedFile(
+            *outputs, script='make-stl-wrappers.py', entry_point='gen_wrappers',
+            flags=[output_dir, stl_compiler, template_file] + stl_headers)
 
     # Wrap <windows.h> to make it easier to use correctly
     # NOTE: If we aren't wrapping STL includes, we're building part of the browser
     # which won't need this wrapper, such as L10N. Just don't try to generate the
     # wrapper in that case.
     if CONFIG['OS_TARGET'] == 'WINNT':
         GeneratedFile('../dist/stl_wrappers/windows.h',
                       script='make-windows-h-wrapper.py',
@@ -73,14 +71,11 @@ if CONFIG['WRAP_STL_INCLUDES']:
                                 'windows-h-unicode.decls.h',
                                 'windows-h-wrapper.template.h'],
                       flags=[stl_compiler])
 
 if CONFIG['WRAP_SYSTEM_INCLUDES']:
     include('system-headers.mozbuild')
     output_dir = '../dist/system_wrappers'
     outputs = tuple(['system-header.sentinel'] + ['%s/%s' % (output_dir, h) for h in stl_headers + system_headers])
-    GENERATED_FILES += [outputs]
-    system = GENERATED_FILES[outputs]
-    system.script = 'make-system-wrappers.py:gen_wrappers'
-    system.flags = [output_dir]
-    system.flags.extend(stl_headers)
-    system.flags.extend(system_headers)
+    GeneratedFile(*outputs, script='make-system-wrappers.py',
+                  entry_point='gen_wrappers',
+                  flags = [output_dir] + stl_headers + system_headers)

--- a/layout/style/test/moz.build
+++ b/layout/style/test/moz.build
@@ -132,15 +132,13 @@ TEST_HARNESS_FILES.testing.mochitest.tes
     '/layout/reftests/svg/as-image/svg-image-visited-1d.html',
     '/layout/reftests/svg/pseudo-classes-02-ref.svg',
     '/layout/reftests/svg/pseudo-classes-02.svg',
 ]
 
 DEFINES['MOZILLA_INTERNAL_API'] = True
 
 if CONFIG['COMPILE_ENVIRONMENT']:
-    GENERATED_FILES += ['css_properties.js']
-    GENERATED_FILES['css_properties.js'].script = 'gen-css-properties.py'
-    GENERATED_FILES['css_properties.js'].inputs = [
-        'css_properties_like_longhand.js',
-        '!host_ListCSSProperties%s' % CONFIG['HOST_BIN_SUFFIX'],
-    ]
+    GeneratedFile('css_properties.js', script='gen-css-properties.py',
+                  inputs=[
+                      'css_properties_like_longhand.js',
+                      '!host_ListCSSProperties%s' % CONFIG['HOST_BIN_SUFFIX']])
     TEST_HARNESS_FILES.testing.mochitest.tests.layout.style.test += ['!css_properties.js']

--- a/media/libdav1d/asm/moz.build
+++ b/media/libdav1d/asm/moz.build
@@ -110,43 +110,31 @@ if CONFIG['CPU_ARCH'] in ('x86', 'x86_64
         'film_grain_init_tmpl.c',
         'ipred_init_tmpl.c',
         'itx_init_tmpl.c',
         'loopfilter_init_tmpl.c',
         'looprestoration_init_tmpl.c',
         'mc_init_tmpl.c',
     ]
 
-    GENERATED_FILES += [
-        '16bd_%s' % p for p in bitdepth_basenames
-    ]
-
-    SOURCES += [
-        '!16bd_%s' % p for p in bitdepth_basenames
-    ]
 
     for f in bitdepth_basenames:
-        a = GENERATED_FILES['16bd_%s' % f]
-        a.script = '../generate_source.py:add_define'
-        a.inputs = [relative_path + f]
-        a.flags = ['BITDEPTH', '16']
-
-    GENERATED_FILES += [
-        '8bd_%s' % p for p in bitdepth_basenames
-    ]
+        SOURCES += [
+            '!16bd_%s' % f
+        ]
+        GeneratedFile('16bd_%s' % f, script='../generate_source.py',
+                      entry_point='add_define', inputs=[relative_path + f],
+                      flags=['BITDEPTH', '16'])
+        SOURCES += [
+            '!8bd_%s' % f
+        ]
+        GeneratedFile('8bd_%s' % f, script='../generate_source.py',
+                      entry_point='add_define', inputs=[relative_path + f],
+                      flags=['BITDEPTH', '8'])
 
-    SOURCES += [
-        '!8bd_%s' % p for p in bitdepth_basenames
-    ]
-
-    for f in bitdepth_basenames:
-        a = GENERATED_FILES['8bd_%s' % f]
-        a.script = '../generate_source.py:add_define'
-        a.inputs = [relative_path + f]
-        a.flags = ['BITDEPTH', '8']
 elif CONFIG['CPU_ARCH'] == 'arm' or CONFIG['CPU_ARCH'] == 'aarch64':
     SOURCES += [
         '../../../third_party/dav1d/src/arm/cpu.c',
     ]
     EXPORTS += [
         '../../../third_party/dav1d/src/arm/cpu.h',
         '../../../third_party/dav1d/src/arm/msac.h',
     ]
@@ -157,43 +145,29 @@ elif CONFIG['CPU_ARCH'] == 'arm' or CONF
         'cdef_init_tmpl.c',
         'ipred_init_tmpl.c',
         'itx_init_tmpl.c',
         'loopfilter_init_tmpl.c',
         'looprestoration_init_tmpl.c',
         'mc_init_tmpl.c',
     ]
 
-    GENERATED_FILES += [
-        '16bd_%s' % p for p in bitdepth_basenames
-    ]
-
-    SOURCES += [
-        '!16bd_%s' % p for p in bitdepth_basenames
-    ]
-
     for f in bitdepth_basenames:
-        a = GENERATED_FILES['16bd_%s' % f]
-        a.script = '../generate_source.py:add_define'
-        a.inputs = [relative_path + f]
-        a.flags = ['BITDEPTH', '16']
-
-    GENERATED_FILES += [
-        '8bd_%s' % p for p in bitdepth_basenames
-    ]
-
-    SOURCES += [
-        '!8bd_%s' % p for p in bitdepth_basenames
-    ]
-
-    for f in bitdepth_basenames:
-        a = GENERATED_FILES['8bd_%s' % f]
-        a.script = '../generate_source.py:add_define'
-        a.inputs = [relative_path + f]
-        a.flags = ['BITDEPTH', '8']
+        SOURCES += [
+            '!16bd_%s' % f
+        ]
+        GeneratedFile('16bd_%s' % f, script='../generate_source.py',
+                      entry_point='add_define', inputs=[relative_path + f],
+                      flags=['BITDEPTH', '16'])
+        SOURCES += [
+            '!8bd_%s' % f
+        ]
+        GeneratedFile('8bd_%s' % f, script='../generate_source.py',
+                      entry_point='add_define', inputs=[relative_path + f],
+                      flags=['BITDEPTH', '8'])
 
     # BITDEPTH .S files
     if CONFIG['CPU_ARCH'] == 'aarch64':
         SOURCES += [
             '../../../third_party/dav1d/src/arm/64/cdef.S',
             '../../../third_party/dav1d/src/arm/64/cdef16.S',
             '../../../third_party/dav1d/src/arm/64/cdef_tmpl.S',
             '../../../third_party/dav1d/src/arm/64/ipred.S',

--- a/media/mp4parse-rust/moz.build
+++ b/media/mp4parse-rust/moz.build
@@ -4,24 +4,17 @@
 # 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/.
 
 EXPORTS += [
     'mp4parse.h',
 ]
 
 if CONFIG['COMPILE_ENVIRONMENT']:
-
-    GENERATED_FILES += [
-        'mp4parse_ffi_generated.h',
-    ]
+    GeneratedFile('mp4parse_ffi_generated.h',
+                  script='/build/RunCbindgen.py', entry_point='generate',
+                  inputs=['/third_party/rust/mp4parse_capi'])
 
     EXPORTS += [ # Should this be namespaced? EXPORTS.mozilla.media
         '!mp4parse_ffi_generated.h',
     ]
 
-    ffi_generated = GENERATED_FILES['mp4parse_ffi_generated.h']
-    ffi_generated.script = '/build/RunCbindgen.py:generate'
-    ffi_generated.inputs = [
-        '/third_party/rust/mp4parse_capi',
-    ]
-
 FINAL_LIBRARY = 'xul'

--- a/modules/libpref/moz.build
+++ b/modules/libpref/moz.build
@@ -116,21 +116,18 @@ EXPORTS.mozilla += sorted(['!' + g for g
 
 UNIFIED_SOURCES += [
     'Preferences.cpp',
     'SharedPrefMap.cpp',
 ]
 
 gen_all_tuple = tuple(gen_h + gen_cpp + gen_rs)
 
-GENERATED_FILES += [gen_all_tuple]
-
-static_pref_list = GENERATED_FILES[gen_all_tuple]
-static_pref_list.script = 'init/generate_static_pref_list.py:emit_code'
-static_pref_list.inputs = ['init/StaticPrefList.yaml']
+GeneratedFile(*gen_all_tuple, script='init/generate_static_pref_list.py',
+              entry_point='emit_code', inputs=['init/StaticPrefList.yaml'])
 
 PYTHON_UNITTEST_MANIFESTS += [
     'test/python.ini',
 ]
 
 XPCOM_MANIFESTS += [
     'components.conf',
 ]

--- a/mozglue/dllservices/moz.build
+++ b/mozglue/dllservices/moz.build
@@ -42,17 +42,15 @@ EXPORTS.mozilla.glue += [
     'WindowsDllServices.h',
 ]
 
 # Generate DLL Blocklists
 blocklist_header_types = ['A11y', 'Launcher', 'Legacy', 'Test']
 blocklist_file_leaf_tpl = 'WindowsDllBlocklist{0}Defs.h'
 blocklist_files = tuple([blocklist_file_leaf_tpl.format(type)
                          for type in blocklist_header_types])
-GENERATED_FILES += [
-    blocklist_files
-]
-blocklist_defs = GENERATED_FILES[blocklist_files]
-blocklist_defs.script = 'gen_dll_blocklist_defs.py:gen_blocklists'
-blocklist_defs.inputs = ['WindowsDllBlocklistDefs.in']
+
+GeneratedFile(*blocklist_files, script='gen_dll_blocklist_defs.py',
+              entry_point='gen_blocklists',
+              inputs=['WindowsDllBlocklistDefs.in'])
 EXPORTS.mozilla += ['!' + hdr for hdr in blocklist_files]
 
 FINAL_LIBRARY = 'mozglue'

--- a/netwerk/dns/tests/unit/data/moz.build
+++ b/netwerk/dns/tests/unit/data/moz.build
@@ -1,14 +1,10 @@
 # -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
 # vim: set filetype=python:
 # 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/.
 
-GENERATED_FILES = ['fake_remote_dafsa.bin']
-
-fake_remote_dafsa = GENERATED_FILES['fake_remote_dafsa.bin']
-fake_remote_dafsa.script = '../../../prepare_tlds.py'
-fake_remote_dafsa.inputs = ['fake_public_suffix_list.dat']
-fake_remote_dafsa.flags = ['bin']
+GeneratedFile('fake_remote_dafsa.bin', script='../../../prepare_tlds.py',
+              inputs=['fake_public_suffix_list.dat'], flags = ['bin'])
 
 TEST_HARNESS_FILES.xpcshell.netwerk.dns.tests.unit.data += ['!fake_remote_dafsa.bin']

--- a/python/mozbuild/mozbuild/frontend/context.py
+++ b/python/mozbuild/mozbuild/frontend/context.py
@@ -1418,16 +1418,22 @@ VARIABLES = {
         """
         ),
 
     'GENERATED_FILES': (
         GeneratedFilesList,
         list,
         """Generic generated files.
 
+        Unless you have a reason not to, use the GeneratedFile template rather
+        than referencing GENERATED_FILES directly. The GeneratedFile template
+        has all the same arguments as the attributes listed below (``script``,
+        ``inputs``, ``flags``, ``force``), plus an additional ``entry_point``
+        argument to specify a particular function to run in the given script.
+
         This variable contains a list of files for the build system to
         generate at export time. The generation method may be declared
         with optional ``script``, ``inputs``, ``flags``, and ``force``
         attributes on individual entries.
         If the optional ``script`` attribute is not present on an entry, it
         is assumed that rules for generating the file are present in
         the associated Makefile.in.
 

--- a/toolkit/components/normandy/test/browser/moz.build
+++ b/toolkit/components/normandy/test/browser/moz.build
@@ -1,8 +1,10 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
 # 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/.
 
 BROWSER_CHROME_MANIFESTS += [
   'browser.ini',
 ]
 
@@ -13,13 +15,11 @@ addons = [
 ]
 
 output_dir = OBJDIR_FILES._tests.testing.mochitest.browser.toolkit.components.normandy.test.browser.addons
 
 for addon in addons:
     indir = 'addons/%s' % addon
     xpi = '%s.xpi' % indir
 
-    GENERATED_FILES += [xpi]
-    GENERATED_FILES[xpi].script = '../create_xpi.py'
-    GENERATED_FILES[xpi].inputs = [indir]
+    GeneratedFile(xpi, script='../create_xpi.py', inputs=[indir])
 
     output_dir += ['!%s' % xpi]

--- a/toolkit/mozapps/extensions/test/browser/moz.build
+++ b/toolkit/mozapps/extensions/test/browser/moz.build
@@ -19,14 +19,12 @@ addons = [
 
 output_dir = OBJDIR_FILES._tests.testing.mochitest.browser.toolkit.mozapps.extensions.test.browser.addons
 
 for addon in addons:
     for file_type in ['xpi', 'zip']:
         indir = 'addons/%s' % addon
         path = '%s.%s' % (indir, file_type)
 
-        GENERATED_FILES += [path]
-        GENERATED_FILES[path].script = '../create_xpi.py'
-        GENERATED_FILES[path].inputs = [indir]
+        GeneratedFile(path, script='../create_xpi.py', inputs=[indir])
 
         output_dir += ['!%s' % path]
 

--- a/widget/android/bindings/moz.build
+++ b/widget/android/bindings/moz.build
@@ -32,17 +32,17 @@ EXPORTS += ['!%s.h' % stem for stem in g
 # The recursive make backend treats the first output specially: it's passed as
 # an open FileAvoidWrite to the invoked script.  That doesn't work well with
 # the Gradle task that generates all of the outputs, so we add a dummy first
 # output.
 t = tuple(['sdk_bindings'] +
           ['%s.cpp' % stem for stem in generated] +
           ['%s.h' % stem for stem in generated])
 
-GENERATED_FILES += [t]
-GENERATED_FILES[t].script = '/mobile/android/gradle.py:generate_sdk_bindings'
-GENERATED_FILES[t].inputs += ['%s-classes.txt' % stem for stem in generated]
+GeneratedFile(*t, script='/mobile/android/gradle.py',
+              entry_point='generate_sdk_bindings',
+              inputs=['%s-classes.txt' % stem for stem in generated])
 
 FINAL_LIBRARY = 'xul'
 
 LOCAL_INCLUDES += [
     '/widget/android',
 ]