diff --git a/gfx/skia/moz.build b/gfx/skia/moz.build
index c9286af7cb38..3c907e04c6e8 100644
--- a/gfx/skia/moz.build
+++ b/gfx/skia/moz.build
@@ -544,7 +544,7 @@ CPP_SOURCES += [
 
 if not CONFIG['INTEL_ARCHITECTURE'] and CONFIG['CPU_ARCH'] == 'arm' and CONFIG['GNU_CC']:
     SSRCS += [
-        'memset.arm.S',
+        'src/opts/memset.arm.S',
     ]
 
 LIBRARY_NAME = 'skia'
diff --git a/gfx/tests/gtest/moz.build b/gfx/tests/gtest/moz.build
index a57a0933cf2c..d79a3ce904d1 100644
--- a/gfx/tests/gtest/moz.build
+++ b/gfx/tests/gtest/moz.build
@@ -27,12 +27,14 @@ GTEST_CPP_SOURCES += [
 # Because of gkmedia on windows we wont find these
 # symbols in xul.dll.
 if CONFIG['MOZ_WIDGET_TOOLKIT'] != 'windows':
-    GTEST_CPP_SOURCES += [
+    GTEST_CPP_SOURCES += [ '%s/gfx/2d/unittest/%s' % (TOPSRCDIR, p) for p in [
         'TestBase.cpp',
-        'TestMoz2D.cpp',
         'TestPoint.cpp',
-        'TestRect.cpp',
         'TestScaling.cpp',
+    ]]
+    GTEST_CPP_SOURCES += [
+        'TestMoz2D.cpp',
+        'TestRect.cpp',
     ]
 
 LIBXUL_LIBRARY = True
diff --git a/ipc/chromium/moz.build b/ipc/chromium/moz.build
index d24083716a15..9aeab43700ad 100644
--- a/ipc/chromium/moz.build
+++ b/ipc/chromium/moz.build
@@ -166,19 +166,19 @@ if os_macosx:
         'src/chrome/common/transport_dib_mac.cc',
     ]
     CMMSRCS += [
-        'base_paths_mac.mm',
-        'chrome_application_mac.mm',
-        'chrome_paths_mac.mm',
-        'file_util_mac.mm',
-        'file_version_info_mac.mm',
-        'mac_util.mm',
-        'mach_ipc_mac.mm',
-        'message_pump_mac.mm',
-        'platform_thread_mac.mm',
-        'process_util_mac.mm',
-        'scoped_nsautorelease_pool.mm',
-        'sys_string_conversions_mac.mm',
-        'worker_pool_mac.mm',
+        'src/base/base_paths_mac.mm',
+        'src/base/chrome_application_mac.mm',
+        'src/base/file_util_mac.mm',
+        'src/base/file_version_info_mac.mm',
+        'src/base/mac_util.mm',
+        'src/base/message_pump_mac.mm',
+        'src/base/platform_thread_mac.mm',
+        'src/base/process_util_mac.mm',
+        'src/base/scoped_nsautorelease_pool.mm',
+        'src/base/sys_string_conversions_mac.mm',
+        'src/base/worker_pool_mac.mm',
+        'src/chrome/common/chrome_paths_mac.mm',
+        'src/chrome/common/mach_ipc_mac.mm',
     ]
 
 if os_linux:
diff --git a/media/libtheora/lib/Makefile.in b/media/libtheora/lib/Makefile.in
index 02819216e96d..b05ee0107636 100644
--- a/media/libtheora/lib/Makefile.in
+++ b/media/libtheora/lib/Makefile.in
@@ -84,6 +84,12 @@ armopts-gnu.S: armopts.s
 %-gnu.$(ASM_SUFFIX): %.s
 	$(PERL) $(srcdir)/arm/arm2gnu.pl < $< > $@
 
+ASFILES += $(addsuffix .$(ASM_SUFFIX), \
+  armbits-gnu \
+  armfrag-gnu \
+  armidct-gnu \
+  armloop-gnu \
+)
 endif
 endif
 
diff --git a/media/libtheora/lib/moz.build b/media/libtheora/lib/moz.build
index 2b225cdc06e1..ec9cabc98e74 100644
--- a/media/libtheora/lib/moz.build
+++ b/media/libtheora/lib/moz.build
@@ -8,15 +8,6 @@ MODULE = 'theora'
 
 LIBRARY_NAME = 'theora'
 
-if CONFIG['OS_TEST'] == 'arm' and CONFIG['GNU_AS']:
-    asm_suffix = CONFIG['ASM_SUFFIX']
-    ASFILES += [ '%s.%s' % (f, asm_suffix) for f in [
-        'armbits-gnu',
-        'armfrag-gnu',
-        'armidct-gnu',
-        'armloop-gnu',
-    ]]
-
 CSRCS += [
     'apiwrapper.c',
     'bitpack.c',
diff --git a/media/libvpx/moz.build b/media/libvpx/moz.build
index 8d383ef1f9a8..186fb0288269 100644
--- a/media/libvpx/moz.build
+++ b/media/libvpx/moz.build
@@ -33,7 +33,7 @@ EXPORTS.vpx += [
 
 if CONFIG['VPX_NEED_OBJ_INT_EXTRACT']:
     HOST_CSRCS += [
-        'obj_int_extract.c',
+        'build/make/obj_int_extract.c',
     ]
 
 LIBRARY_NAME = 'vpx'
diff --git a/python/mozbuild/mozbuild/frontend/emitter.py b/python/mozbuild/mozbuild/frontend/emitter.py
index 27fa13086183..581fbdf48475 100644
--- a/python/mozbuild/mozbuild/frontend/emitter.py
+++ b/python/mozbuild/mozbuild/frontend/emitter.py
@@ -128,7 +128,9 @@ class TreeMetadataEmitter(LoggingMixin):
             yield XPIDLFile(sandbox, mozpath.join(sandbox['SRCDIR'], idl),
                 xpidl_module)
 
-        for symbol in ('CPP_SOURCES', 'CSRCS'):
+        for symbol in ('CPP_SOURCES', 'CSRCS', 'ASFILES', 'CMMSRCS', 'SSRCS',
+                       'GTEST_CMM_SOURCES', 'GTEST_CPP_SOURCES',
+                       'GTEST_C_SOURCES', 'HOST_CPPSRCS', 'HOST_CSRCS'):
             for src in (sandbox[symbol] or []):
                 if not os.path.exists(os.path.join(sandbox['SRCDIR'], src)):
                     raise SandboxValidationError('Reference to a file that '
diff --git a/python/mozbuild/mozbuild/test/backend/data/variable_passthru/bar.cpp b/python/mozbuild/mozbuild/test/backend/data/variable_passthru/bar.cpp
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/python/mozbuild/mozbuild/test/backend/data/variable_passthru/bar.mm b/python/mozbuild/mozbuild/test/backend/data/variable_passthru/bar.mm
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/python/mozbuild/mozbuild/test/backend/data/variable_passthru/bar.s b/python/mozbuild/mozbuild/test/backend/data/variable_passthru/bar.s
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/python/mozbuild/mozbuild/test/backend/data/variable_passthru/baz.S b/python/mozbuild/mozbuild/test/backend/data/variable_passthru/baz.S
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/python/mozbuild/mozbuild/test/backend/data/variable_passthru/foo.S b/python/mozbuild/mozbuild/test/backend/data/variable_passthru/foo.S
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/python/mozbuild/mozbuild/test/backend/data/variable_passthru/foo.asm b/python/mozbuild/mozbuild/test/backend/data/variable_passthru/foo.asm
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/python/mozbuild/mozbuild/test/backend/data/variable_passthru/foo.cpp b/python/mozbuild/mozbuild/test/backend/data/variable_passthru/foo.cpp
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/python/mozbuild/mozbuild/test/backend/data/variable_passthru/foo.mm b/python/mozbuild/mozbuild/test/backend/data/variable_passthru/foo.mm
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/python/mozbuild/mozbuild/test/backend/data/variable_passthru/moz.build b/python/mozbuild/mozbuild/test/backend/data/variable_passthru/moz.build
index 396737b1b328..a94ddebd0cb7 100644
--- a/python/mozbuild/mozbuild/test/backend/data/variable_passthru/moz.build
+++ b/python/mozbuild/mozbuild/test/backend/data/variable_passthru/moz.build
@@ -38,7 +38,7 @@ CSRCS += ['bar.c', 'foo.c']
 
 CMMSRCS = ['bar.mm', 'foo.mm']
 
-SSRCS = ['bar.S', 'foo.S']
+SSRCS = ['baz.S', 'foo.S']
 
 FAIL_ON_WARNINGS = True
 LIBXUL_LIBRARY = True
diff --git a/python/mozbuild/mozbuild/test/backend/data/variable_passthru/test1.c b/python/mozbuild/mozbuild/test/backend/data/variable_passthru/test1.c
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/python/mozbuild/mozbuild/test/backend/data/variable_passthru/test1.cpp b/python/mozbuild/mozbuild/test/backend/data/variable_passthru/test1.cpp
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/python/mozbuild/mozbuild/test/backend/data/variable_passthru/test1.mm b/python/mozbuild/mozbuild/test/backend/data/variable_passthru/test1.mm
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/python/mozbuild/mozbuild/test/backend/data/variable_passthru/test2.c b/python/mozbuild/mozbuild/test/backend/data/variable_passthru/test2.c
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/python/mozbuild/mozbuild/test/backend/data/variable_passthru/test2.cpp b/python/mozbuild/mozbuild/test/backend/data/variable_passthru/test2.cpp
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/python/mozbuild/mozbuild/test/backend/data/variable_passthru/test2.mm b/python/mozbuild/mozbuild/test/backend/data/variable_passthru/test2.mm
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/python/mozbuild/mozbuild/test/backend/test_recursivemake.py b/python/mozbuild/mozbuild/test/backend/test_recursivemake.py
index 472396629e04..9835641b17bd 100644
--- a/python/mozbuild/mozbuild/test/backend/test_recursivemake.py
+++ b/python/mozbuild/mozbuild/test/backend/test_recursivemake.py
@@ -355,7 +355,7 @@ class TestRecursiveMakeBackend(BackendTester):
                 'SIMPLE_PROGRAMS += foo.x',
             ],
             'SSRCS': [
-                'SSRCS += bar.S',
+                'SSRCS += baz.S',
                 'SSRCS += foo.S',
             ],
         }
diff --git a/python/mozbuild/mozbuild/test/frontend/data/variable-passthru/bans.S b/python/mozbuild/mozbuild/test/frontend/data/variable-passthru/bans.S
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/python/mozbuild/mozbuild/test/frontend/data/variable-passthru/fans.S b/python/mozbuild/mozbuild/test/frontend/data/variable-passthru/fans.S
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/python/mozbuild/mozbuild/test/frontend/data/variable-passthru/fans.asm b/python/mozbuild/mozbuild/test/frontend/data/variable-passthru/fans.asm
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/python/mozbuild/mozbuild/test/frontend/data/variable-passthru/fans.cpp b/python/mozbuild/mozbuild/test/frontend/data/variable-passthru/fans.cpp
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/python/mozbuild/mozbuild/test/frontend/data/variable-passthru/fans.mm b/python/mozbuild/mozbuild/test/frontend/data/variable-passthru/fans.mm
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/python/mozbuild/mozbuild/test/frontend/data/variable-passthru/moz.build b/python/mozbuild/mozbuild/test/frontend/data/variable-passthru/moz.build
index b6ac05209f2c..d7b85db6e0be 100644
--- a/python/mozbuild/mozbuild/test/frontend/data/variable-passthru/moz.build
+++ b/python/mozbuild/mozbuild/test/frontend/data/variable-passthru/moz.build
@@ -38,7 +38,7 @@ CSRCS += ['fans.c', 'tans.c']
 
 CMMSRCS = ['fans.mm', 'tans.mm']
 
-SSRCS = ['fans.S', 'tans.S']
+SSRCS = ['bans.S', 'fans.S']
 
 FAIL_ON_WARNINGS = True
 LIBXUL_LIBRARY = True
diff --git a/python/mozbuild/mozbuild/test/frontend/data/variable-passthru/tans.cpp b/python/mozbuild/mozbuild/test/frontend/data/variable-passthru/tans.cpp
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/python/mozbuild/mozbuild/test/frontend/data/variable-passthru/tans.mm b/python/mozbuild/mozbuild/test/frontend/data/variable-passthru/tans.mm
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/python/mozbuild/mozbuild/test/frontend/data/variable-passthru/tans.s b/python/mozbuild/mozbuild/test/frontend/data/variable-passthru/tans.s
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/python/mozbuild/mozbuild/test/frontend/data/variable-passthru/test1.c b/python/mozbuild/mozbuild/test/frontend/data/variable-passthru/test1.c
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/python/mozbuild/mozbuild/test/frontend/data/variable-passthru/test1.cpp b/python/mozbuild/mozbuild/test/frontend/data/variable-passthru/test1.cpp
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/python/mozbuild/mozbuild/test/frontend/data/variable-passthru/test1.mm b/python/mozbuild/mozbuild/test/frontend/data/variable-passthru/test1.mm
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/python/mozbuild/mozbuild/test/frontend/data/variable-passthru/test2.c b/python/mozbuild/mozbuild/test/frontend/data/variable-passthru/test2.c
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/python/mozbuild/mozbuild/test/frontend/data/variable-passthru/test2.cpp b/python/mozbuild/mozbuild/test/frontend/data/variable-passthru/test2.cpp
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/python/mozbuild/mozbuild/test/frontend/data/variable-passthru/test2.mm b/python/mozbuild/mozbuild/test/frontend/data/variable-passthru/test2.mm
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/python/mozbuild/mozbuild/test/frontend/test_emitter.py b/python/mozbuild/mozbuild/test/frontend/test_emitter.py
index 5940d97aa8a4..b125884a0eeb 100644
--- a/python/mozbuild/mozbuild/test/frontend/test_emitter.py
+++ b/python/mozbuild/mozbuild/test/frontend/test_emitter.py
@@ -162,7 +162,7 @@ class TestEmitterBasic(unittest.TestCase):
             SDK_LIBRARY=['fans.sdk', 'tans.sdk'],
             SHARED_LIBRARY_LIBS=['fans.sll', 'tans.sll'],
             SIMPLE_PROGRAMS=['fans.x', 'tans.x'],
-            SSRCS=['fans.S', 'tans.S'],
+            SSRCS=['bans.S', 'fans.S'],
         )
 
         variables = objs[1].variables
diff --git a/testing/gtest/moz.build b/testing/gtest/moz.build
index 0e24e29a9cc2..4da5dee19b17 100644
--- a/testing/gtest/moz.build
+++ b/testing/gtest/moz.build
@@ -62,7 +62,7 @@ CPP_SOURCES += [
 LIBRARY_NAME = 'gtest'
 
 GTEST_CPP_SOURCES += [
-    'SanityTest.cpp',
+    'mozilla/SanityTest.cpp',
 ]
 
 LIBXUL_LIBRARY = True
diff --git a/toolkit/crashreporter/google-breakpad/src/common/moz.build b/toolkit/crashreporter/google-breakpad/src/common/moz.build
index e922a319585f..8b643b471460 100644
--- a/toolkit/crashreporter/google-breakpad/src/common/moz.build
+++ b/toolkit/crashreporter/google-breakpad/src/common/moz.build
@@ -77,7 +77,7 @@ if CONFIG['OS_ARCH'] == 'Darwin':
 
 if CONFIG['OS_TARGET'] == 'Android':
     SSRCS += [
-        'breakpad_getcontext.S',
+        'android/breakpad_getcontext.S',
     ]
 
 LIBRARY_NAME = 'breakpad_common_s'
diff --git a/uriloader/exthandler/moz.build b/uriloader/exthandler/moz.build
index c9bd5790f2ab..e102dfbb7c9e 100644
--- a/uriloader/exthandler/moz.build
+++ b/uriloader/exthandler/moz.build
@@ -67,9 +67,9 @@ CPP_SOURCES += [
 
 if CONFIG['MOZ_WIDGET_TOOLKIT'] == 'cocoa':
     CMMSRCS += [
-        'nsLocalHandlerAppMac.mm',
-        'nsMIMEInfoMac.mm',
-        'nsOSHelperAppService.mm',
+        'mac/nsLocalHandlerAppMac.mm',
+        'mac/nsMIMEInfoMac.mm',
+        'mac/nsOSHelperAppService.mm',
     ]
 else:
     CPP_SOURCES += [