diff --git a/js/src/builtin/moz.build b/js/src/builtin/moz.build
new file mode 100644
index 000000000..ebf9318db
--- /dev/null
+++ b/js/src/builtin/moz.build
@@ -0,0 +1,73 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# 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/.
+
+include('../js-config.mozbuild')
+include('../js-cxxflags.mozbuild')
+
+FINAL_LIBRARY = "js"
+
+# Includes should be relative to parent path
+LOCAL_INCLUDES += ["!..", ".."]
+
+SOURCES += [
+    'AtomicsObject.cpp',
+    'Eval.cpp',
+    'Intl.cpp',
+    'MapObject.cpp',
+    'ModuleObject.cpp',
+    'Object.cpp',
+    'Profilers.cpp',
+    'Promise.cpp',
+    'Reflect.cpp',
+    'ReflectParse.cpp',
+    'RegExp.cpp',
+    'SIMD.cpp',
+    'SymbolObject.cpp',
+    'TestingFunctions.cpp',
+    'TypedObject.cpp',
+    'WeakMapObject.cpp',
+    'WeakSetObject.cpp',
+]
+
+if CONFIG['_MSC_VER']:
+    if CONFIG['CPU_ARCH'] == 'x86':
+        SOURCES['RegExp.cpp'].no_pgo = True # Bug 772303
+
+# Prepare self-hosted JS code for embedding
+GENERATED_FILES += [('selfhosted.out.h', 'selfhosted.js')]
+selfhosted = GENERATED_FILES[('selfhosted.out.h', 'selfhosted.js')]
+selfhosted.script = 'embedjs.py:generate_selfhosted'
+selfhosted.inputs = [
+    '../js.msg',
+    'TypedObjectConstants.h',
+    'SelfHostingDefines.h',
+    'Utilities.js',
+    'Array.js',
+    'AsyncIteration.js',
+    'Classes.js',
+    'Date.js',
+    'Error.js',
+    'Function.js',
+    'Generator.js',
+    'Intl.js',
+    'IntlData.js',
+    'Iterator.js',
+    'Map.js',
+    'Module.js',
+    'Number.js',
+    'Object.js',
+    'Promise.js',
+    'Reflect.js',
+    'RegExp.js',
+    'RegExpGlobalReplaceOpt.h.js',
+    'RegExpLocalReplaceOpt.h.js',
+    'String.js',
+    'Set.js',
+    'Sorting.js',
+    'TypedArray.js',
+    'TypedObject.js',
+    'WeakMap.js',
+    'WeakSet.js',
+]
diff --git a/js/src/ctypes/moz.build b/js/src/ctypes/moz.build
new file mode 100644
index 000000000..5bea399f3
--- /dev/null
+++ b/js/src/ctypes/moz.build
@@ -0,0 +1,26 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# 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/.
+
+include('../js-config.mozbuild')
+include('../js-cxxflags.mozbuild')
+
+FINAL_LIBRARY = "js"
+
+# Includes should be relative to parent path
+LOCAL_INCLUDES += ["!..", ".."]
+
+SOURCES += [
+    'CTypes.cpp',
+    'Library.cpp',
+]
+
+if not CONFIG['MOZ_SYSTEM_FFI']:
+    LOCAL_INCLUDES += [
+        '!libffi/include',
+        'libffi/src/%s' % CONFIG['FFI_TARGET_DIR'],
+    ]
+
+if CONFIG['_MSC_VER'] and CONFIG['CPU_ARCH'] == 'x86_64':
+    SOURCES['CTypes.cpp'].no_pgo = True # Bug 810661
\ No newline at end of file
diff --git a/js/src/devtools/moz.build b/js/src/devtools/moz.build
new file mode 100644
index 000000000..cb2fc3256
--- /dev/null
+++ b/js/src/devtools/moz.build
@@ -0,0 +1,25 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# 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/.
+
+include('../js-config.mozbuild')
+include('../js-cxxflags.mozbuild')
+
+FINAL_LIBRARY = "js"
+
+# Includes should be relative to parent path
+LOCAL_INCLUDES += ["!..", ".."]
+
+CONFIGURE_SUBST_FILES += [
+    'rootAnalysis/Makefile',
+]
+
+SOURCES += [
+    'sharkctl.cpp',
+]
+
+if CONFIG['MOZ_INSTRUMENTS']:
+    SOURCES += [
+        'Instruments.cpp',
+    ]
diff --git a/js/src/ds/moz.build b/js/src/ds/moz.build
new file mode 100644
index 000000000..a0b869706
--- /dev/null
+++ b/js/src/ds/moz.build
@@ -0,0 +1,17 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# 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/.
+
+include('../js-config.mozbuild')
+include('../js-cxxflags.mozbuild')
+
+FINAL_LIBRARY = "js"
+
+# Includes should be relative to parent path
+LOCAL_INCLUDES += ["!..", ".."]
+
+SOURCES += [
+    'LifoAlloc.cpp',
+    'MemoryProtectionExceptionHandler.cpp',
+]
\ No newline at end of file
diff --git a/js/src/frontend/moz.build b/js/src/frontend/moz.build
new file mode 100644
index 000000000..55037dd5a
--- /dev/null
+++ b/js/src/frontend/moz.build
@@ -0,0 +1,27 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# 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/.
+
+include('../js-config.mozbuild')
+include('../js-cxxflags.mozbuild')
+
+FINAL_LIBRARY = "js"
+
+# Includes should be relative to parent path
+LOCAL_INCLUDES += ["!..", ".."]
+
+SOURCES += [
+    'BytecodeCompiler.cpp',
+    'BytecodeEmitter.cpp',
+    'FoldConstants.cpp',
+    'NameFunctions.cpp',
+    'ParseNode.cpp',
+    'Parser.cpp',
+    'TokenStream.cpp',
+]
+
+GENERATED_FILES += ['ReservedWordsGenerated.h']
+ReservedWordsGenerated = GENERATED_FILES['ReservedWordsGenerated.h']
+ReservedWordsGenerated.script = 'GenerateReservedWords.py'
+ReservedWordsGenerated.inputs += ['ReservedWords.h']
\ No newline at end of file
diff --git a/js/src/gc/moz.build b/js/src/gc/moz.build
new file mode 100644
index 000000000..d33dfb007
--- /dev/null
+++ b/js/src/gc/moz.build
@@ -0,0 +1,31 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# 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/.
+
+include('../js-config.mozbuild')
+include('../js-cxxflags.mozbuild')
+
+FINAL_LIBRARY = "js"
+
+# Includes should be relative to parent path
+LOCAL_INCLUDES += ["!..", ".."]
+
+SOURCES += [
+    'Allocator.cpp',
+    'Barrier.cpp',
+    'GCTrace.cpp',
+    'Iteration.cpp',
+    'Marking.cpp',
+    'Memory.cpp',
+    'MemoryProfiler.cpp',
+    'Nursery.cpp',
+    'RootMarking.cpp',
+    'Statistics.cpp',
+    'StoreBuffer.cpp',
+    'Tracer.cpp',
+    'Zone.cpp',
+]
+
+if CONFIG['MOZ_DEBUG']:
+    SOURCES += ['Verifier.cpp']
diff --git a/js/src/gdb/moz.build b/js/src/gdb/moz.build
index a2e935624..01f6cb0b6 100644
--- a/js/src/gdb/moz.build
+++ b/js/src/gdb/moz.build
@@ -5,6 +5,8 @@
 
 GeckoProgram('gdb-tests', linkage=None)
 
+include('../js-cxxflags.mozbuild')
+
 UNIFIED_SOURCES += [
     'gdb-tests.cpp',
     'tests/test-asmjs.cpp',
@@ -40,13 +42,6 @@ if CONFIG['MOZ_ICU_DATA_ARCHIVE']:
 
 OS_LIBS += CONFIG['MOZ_ZLIB_LIBS']
 
-if CONFIG['GNU_CXX']:
-    CXXFLAGS += ['-Wno-shadow', '-fno-strict-aliasing']
-
-# This is intended as a temporary workaround to enable VS2015.
-if CONFIG['_MSC_VER']:
-    CXXFLAGS += ['-wd4312']
-
 DEFINES['topsrcdir'] = '%s/js/src' % TOPSRCDIR
 FINAL_TARGET_PP_FILES += ['gdb-tests-gdb.py.in']
 OBJDIR_FILES.js.src.gdb += ['!/dist/bin/gdb-tests-gdb.py']
diff --git a/js/src/irregexp/moz.build b/js/src/irregexp/moz.build
new file mode 100644
index 000000000..fc4fe6218
--- /dev/null
+++ b/js/src/irregexp/moz.build
@@ -0,0 +1,23 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# 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/.
+
+include('../js-config.mozbuild')
+include('../js-cxxflags.mozbuild')
+
+FINAL_LIBRARY = "js"
+
+# Includes should be relative to parent path
+LOCAL_INCLUDES += ["!..", ".."]
+
+SOURCES += [
+    'NativeRegExpMacroAssembler.cpp',
+    'RegExpAST.cpp',
+    'RegExpCharacters.cpp',
+    'RegExpEngine.cpp',
+    'RegExpInterpreter.cpp',
+    'RegExpMacroAssembler.cpp',
+    'RegExpParser.cpp',
+    'RegExpStack.cpp',
+]
\ No newline at end of file
diff --git a/js/src/jit/moz.build b/js/src/jit/moz.build
new file mode 100644
index 000000000..e8b463112
--- /dev/null
+++ b/js/src/jit/moz.build
@@ -0,0 +1,233 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# 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/.
+
+include('../js-config.mozbuild')
+include('../js-cxxflags.mozbuild')
+
+FINAL_LIBRARY = "js"
+
+# Includes should be relative to parent path
+LOCAL_INCLUDES += ["!..", ".."]
+
+UNIFIED_SOURCES += [
+    'AliasAnalysis.cpp',
+    'AliasAnalysisShared.cpp',
+    'AlignmentMaskAnalysis.cpp',
+    'BacktrackingAllocator.cpp',
+    'Bailouts.cpp',
+    'BaselineBailouts.cpp',
+    'BaselineCacheIR.cpp',
+    'BaselineCompiler.cpp',
+    'BaselineDebugModeOSR.cpp',
+    'BaselineFrame.cpp',
+    'BaselineFrameInfo.cpp',
+    'BaselineIC.cpp',
+    'BaselineInspector.cpp',
+    'BaselineJIT.cpp',
+    'BitSet.cpp',
+    'BytecodeAnalysis.cpp',
+    'C1Spewer.cpp',
+    'CacheIR.cpp',
+    'CodeGenerator.cpp',
+    'CompileWrappers.cpp',
+    'EagerSimdUnbox.cpp',
+    'EdgeCaseAnalysis.cpp',
+    'EffectiveAddressAnalysis.cpp',
+    'ExecutableAllocator.cpp',
+    'FlowAliasAnalysis.cpp',
+    'FoldLinearArithConstants.cpp',
+    'InstructionReordering.cpp',
+    'Ion.cpp',
+    'IonAnalysis.cpp',
+    'IonBuilder.cpp',
+    'IonCaches.cpp',
+    'IonOptimizationLevels.cpp',
+    'JitcodeMap.cpp',
+    'JitFrames.cpp',
+    'JitOptions.cpp',
+    'JitSpewer.cpp',
+    'JSONSpewer.cpp',
+    'LICM.cpp',
+    'Linker.cpp',
+    'LIR.cpp',
+    'LoopUnroller.cpp',
+    'Lowering.cpp',
+    'MacroAssembler.cpp',
+    'MCallOptimize.cpp',
+    'MIR.cpp',
+    'MIRGraph.cpp',
+    'MoveResolver.cpp',
+    'OptimizationTracking.cpp',
+    'PerfSpewer.cpp',
+    'ProcessExecutableMemory.cpp',
+    'RangeAnalysis.cpp',
+    'Recover.cpp',
+    'RegisterAllocator.cpp',
+    'RematerializedFrame.cpp',
+    'Safepoints.cpp',
+    'ScalarReplacement.cpp',
+    'shared/BaselineCompiler-shared.cpp',
+    'shared/CodeGenerator-shared.cpp',
+    'shared/Lowering-shared.cpp',
+    'SharedIC.cpp',
+    'Sink.cpp',
+    'Snapshots.cpp',
+    'StupidAllocator.cpp',
+    'TypedObjectPrediction.cpp',
+    'TypePolicy.cpp',
+    'ValueNumbering.cpp',
+    'VMFunctions.cpp',
+    'WasmBCE.cpp',
+]
+
+if CONFIG['MOZ_DEBUG']:
+    UNIFIED_SOURCES += ['Disassembler.cpp']
+
+if not CONFIG['ENABLE_ION']:
+    UNIFIED_SOURCES += [
+        'none/Trampoline-none.cpp'
+    ]
+elif CONFIG['JS_CODEGEN_X86'] or CONFIG['JS_CODEGEN_X64']:
+    UNIFIED_SOURCES += [
+        'x86-shared/Architecture-x86-shared.cpp',
+        'x86-shared/Assembler-x86-shared.cpp',
+        'x86-shared/AssemblerBuffer-x86-shared.cpp',
+        'x86-shared/BaselineCompiler-x86-shared.cpp',
+        'x86-shared/BaselineIC-x86-shared.cpp',
+        'x86-shared/CodeGenerator-x86-shared.cpp',
+        'x86-shared/Lowering-x86-shared.cpp',
+        'x86-shared/MacroAssembler-x86-shared.cpp',
+        'x86-shared/MoveEmitter-x86-shared.cpp',
+    ]
+    UNIFIED_SOURCES += [
+        'x86-shared/Disassembler-x86-shared.cpp',  # using namespace js::jit::X86Encoding;
+    ]
+    if CONFIG['JS_CODEGEN_X64']:
+        UNIFIED_SOURCES += [
+            'x64/Assembler-x64.cpp',
+            'x64/Bailouts-x64.cpp',
+            'x64/BaselineCompiler-x64.cpp',
+            'x64/BaselineIC-x64.cpp',
+            'x64/CodeGenerator-x64.cpp',
+            'x64/Lowering-x64.cpp',
+            'x64/MacroAssembler-x64.cpp',
+            'x64/SharedIC-x64.cpp',
+            'x64/Trampoline-x64.cpp',
+        ]
+    else:
+        UNIFIED_SOURCES += [
+            'x86/Assembler-x86.cpp',
+            'x86/Bailouts-x86.cpp',
+            'x86/BaselineCompiler-x86.cpp',
+            'x86/BaselineIC-x86.cpp',
+            'x86/CodeGenerator-x86.cpp',
+            'x86/Lowering-x86.cpp',
+            'x86/MacroAssembler-x86.cpp',
+            'x86/SharedIC-x86.cpp',
+            'x86/Trampoline-x86.cpp',
+        ]
+elif CONFIG['JS_CODEGEN_ARM']:
+    UNIFIED_SOURCES += [
+        'arm/Architecture-arm.cpp',
+        'arm/Assembler-arm.cpp',
+        'arm/Bailouts-arm.cpp',
+        'arm/BaselineCompiler-arm.cpp',
+        'arm/BaselineIC-arm.cpp',
+        'arm/CodeGenerator-arm.cpp',
+        'arm/disasm/Constants-arm.cpp',
+        'arm/disasm/Disasm-arm.cpp',
+        'arm/Lowering-arm.cpp',
+        'arm/MacroAssembler-arm.cpp',
+        'arm/MoveEmitter-arm.cpp',
+        'arm/SharedIC-arm.cpp',
+        'arm/Trampoline-arm.cpp',
+    ]
+    if CONFIG['JS_SIMULATOR_ARM']:
+        UNIFIED_SOURCES += [
+            'arm/Simulator-arm.cpp'
+        ]
+    elif CONFIG['OS_ARCH'] == 'Darwin':
+        UNIFIED_SOURCES += [
+            'arm/llvm-compiler-rt/arm/aeabi_idivmod.S',
+            'arm/llvm-compiler-rt/arm/aeabi_uidivmod.S',
+        ]
+elif CONFIG['JS_CODEGEN_ARM64']:
+    UNIFIED_SOURCES += [
+        'arm64/Architecture-arm64.cpp',
+        'arm64/Assembler-arm64.cpp',
+        'arm64/Bailouts-arm64.cpp',
+        'arm64/BaselineIC-arm64.cpp',
+        'arm64/CodeGenerator-arm64.cpp',
+        'arm64/Lowering-arm64.cpp',
+        'arm64/MacroAssembler-arm64.cpp',
+        'arm64/MoveEmitter-arm64.cpp',
+        'arm64/SharedIC-arm64.cpp',
+        'arm64/Trampoline-arm64.cpp',
+        'arm64/vixl/Assembler-vixl.cpp',
+        'arm64/vixl/Cpu-vixl.cpp',
+        'arm64/vixl/Decoder-vixl.cpp',
+        'arm64/vixl/Disasm-vixl.cpp',
+        'arm64/vixl/Instructions-vixl.cpp',
+        'arm64/vixl/Instrument-vixl.cpp',
+        'arm64/vixl/MacroAssembler-vixl.cpp',
+        'arm64/vixl/MozAssembler-vixl.cpp',
+        'arm64/vixl/MozInstructions-vixl.cpp',
+        'arm64/vixl/Utils-vixl.cpp'
+    ]
+    if CONFIG['JS_SIMULATOR_ARM64']:
+        UNIFIED_SOURCES += [
+            'arm64/vixl/Debugger-vixl.cpp',
+            'arm64/vixl/Logic-vixl.cpp',
+            'arm64/vixl/MozSimulator-vixl.cpp',
+            'arm64/vixl/Simulator-vixl.cpp'
+        ]
+elif CONFIG['JS_CODEGEN_MIPS32'] or CONFIG['JS_CODEGEN_MIPS64']:
+    UNIFIED_SOURCES += [
+        'mips-shared/Architecture-mips-shared.cpp',
+        'mips-shared/Assembler-mips-shared.cpp',
+        'mips-shared/Bailouts-mips-shared.cpp',
+        'mips-shared/BaselineCompiler-mips-shared.cpp',
+        'mips-shared/BaselineIC-mips-shared.cpp',
+        'mips-shared/CodeGenerator-mips-shared.cpp',
+        'mips-shared/Lowering-mips-shared.cpp',
+        'mips-shared/MacroAssembler-mips-shared.cpp',
+        'mips-shared/MoveEmitter-mips-shared.cpp',
+    ]
+    if CONFIG['JS_CODEGEN_MIPS32']:
+        UNIFIED_SOURCES += [
+            'mips32/Architecture-mips32.cpp',
+            'mips32/Assembler-mips32.cpp',
+            'mips32/Bailouts-mips32.cpp',
+            'mips32/BaselineCompiler-mips32.cpp',
+            'mips32/BaselineIC-mips32.cpp',
+            'mips32/CodeGenerator-mips32.cpp',
+            'mips32/Lowering-mips32.cpp',
+            'mips32/MacroAssembler-mips32.cpp',
+            'mips32/MoveEmitter-mips32.cpp',
+            'mips32/SharedIC-mips32.cpp',
+            'mips32/Trampoline-mips32.cpp',
+        ]
+        if CONFIG['JS_SIMULATOR_MIPS32']:
+            UNIFIED_SOURCES += [
+                'mips32/Simulator-mips32.cpp'
+            ]
+    elif CONFIG['JS_CODEGEN_MIPS64']:
+        UNIFIED_SOURCES += [
+            'mips64/Architecture-mips64.cpp',
+            'mips64/Assembler-mips64.cpp',
+            'mips64/Bailouts-mips64.cpp',
+            'mips64/BaselineCompiler-mips64.cpp',
+            'mips64/BaselineIC-mips64.cpp',
+            'mips64/CodeGenerator-mips64.cpp',
+            'mips64/Lowering-mips64.cpp',
+            'mips64/MacroAssembler-mips64.cpp',
+            'mips64/MoveEmitter-mips64.cpp',
+            'mips64/SharedIC-mips64.cpp',
+            'mips64/Trampoline-mips64.cpp',
+        ]
+        if CONFIG['JS_SIMULATOR_MIPS64']:
+            UNIFIED_SOURCES += [
+                'mips64/Simulator-mips64.cpp'
+            ]
diff --git a/js/src/js-config.mozbuild b/js/src/js-config.mozbuild
new file mode 100644
index 000000000..4166c0ad1
--- /dev/null
+++ b/js/src/js-config.mozbuild
@@ -0,0 +1,34 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# 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/.
+
+FILES_PER_UNIFIED_FILE = 6
+
+# Also set in shell/moz.build
+DEFINES['ENABLE_SHARED_ARRAY_BUFFER'] = True
+
+DEFINES['EXPORT_JS_API'] = True
+
+if CONFIG['NIGHTLY_BUILD']:
+    DEFINES['ENABLE_BINARYDATA'] = True
+
+if CONFIG['NIGHTLY_BUILD']:
+    DEFINES['ENABLE_SIMD'] = True
+
+if CONFIG['JS_HAS_CTYPES']:
+    DEFINES['JS_HAS_CTYPES'] = True
+    for var in ('DLL_PREFIX', 'DLL_SUFFIX'):
+        DEFINES[var] = '"%s"' % CONFIG[var]
+
+if CONFIG['MOZ_LINKER']:
+    DEFINES['MOZ_LINKER'] = True
+
+if CONFIG['JS_HAS_CTYPES']:
+    if not CONFIG['MOZ_SYSTEM_FFI']:
+        # Windows needs this to be linked with a static library.
+        DEFINES['FFI_BUILDING'] = True
+
+if CONFIG['OS_ARCH'] == 'WINNT':
+    DEFINES['_CRT_RAND_S'] = True
+    DEFINES['NOMINMAX'] = True
\ No newline at end of file
diff --git a/js/src/js-cxxflags.mozbuild b/js/src/js-cxxflags.mozbuild
new file mode 100644
index 000000000..3cab923f1
--- /dev/null
+++ b/js/src/js-cxxflags.mozbuild
@@ -0,0 +1,42 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# 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/.
+
+CFLAGS += CONFIG['MOZ_ICU_CFLAGS']
+CXXFLAGS += CONFIG['MOZ_ICU_CFLAGS']
+
+if CONFIG['_MSC_VER']:
+    # Prevent floating point errors caused by VC++ optimizations
+    CFLAGS += ['-fp:precise']
+    CXXFLAGS += ['-fp:precise']  
+
+    # C4805 warns mixing bool with other integral types in computation.
+    # But given the conversion from bool is specified, and this is a
+    # pattern widely used in code in js/src, suppress this warning here.
+    CXXFLAGS += ['-wd4805']
+
+    # C4661 ("no suitable definition provided for explicit template
+    # instantiation request") is emitted for all Parser methods that
+    # have a Parser<FullParseHandler> definition but no
+    # Parser<SyntaxParseHandler> definition, see bug 1167030.
+    CXXFLAGS += ['-wd4661', '-we4067', '-we4258', '-we4275']
+    CXXFLAGS += ['-wd4146'] # FIXME: unary minus operator applied to unsigned type (bug 1229189)
+
+    # This is intended as a temporary hack to support building with VS2015.
+    # 'noexcept' used with no exception handling mode specified;
+    # termination on exception is not guaranteed. Specify /EHsc
+    CXXFLAGS += ['-wd4577', '-wd4312']
+
+if CONFIG['GNU_CXX']:
+    # Disable strict-aliasing for GCC, which is enabled by default
+    # starting with version 7.1, see Mozilla bug 1363009.
+    CXXFLAGS += ['-Wno-shadow', '-Werror=format', '-fno-strict-aliasing']
+
+if CONFIG['JS_HAS_CTYPES'] and CONFIG['MOZ_SYSTEM_FFI']:
+    CXXFLAGS += CONFIG['MOZ_FFI_CFLAGS']
+
+if CONFIG['JS_CODEGEN_ARM'] and CONFIG['JS_SIMULATOR_ARM']:
+    # Configuration used only for testing.
+    if CONFIG['OS_ARCH'] == 'Linux' or CONFIG['OS_ARCH'] == 'Darwin':
+        CXXFLAGS += [ '-msse2', '-mfpmath=sse' ]
\ No newline at end of file
diff --git a/js/src/js-testing.mozbuild b/js/src/js-testing.mozbuild
new file mode 100644
index 000000000..a880d9831
--- /dev/null
+++ b/js/src/js-testing.mozbuild
@@ -0,0 +1,48 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# 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/.
+
+component_engine = ('Core', 'JavaScript Engine')
+component_gc     = ('Core', 'JavaScript: GC')
+component_intl   = ('Core', 'JavaScript: Internationalization API')
+component_jit    = ('Core', 'JavaScript Engine: JIT')
+component_stl    = ('Core', 'JavaScript: Standard Library')
+
+with Files('../public/**'):
+    BUG_COMPONENT = component_engine
+with Files('*'):
+    BUG_COMPONENT = component_engine
+
+with Files('wasm/**'):
+    BUG_COMPONENT = component_jit
+with Files('builtin/**'):
+    BUG_COMPONENT = component_stl
+with Files('ctypes/**'):
+    BUG_COMPONENT = ('Core', 'js-ctypes')
+with Files('gc/**'):
+    BUG_COMPONENT = component_gc
+with Files('jit/**'):
+    BUG_COMPONENT = component_jit
+
+# File-specific metadata
+for gcfile in ['jsgc*', 'devtools/rootAnalysis', 'devtools/gc-ubench', 'devtools/gctrace']:
+    with Files(gcfile):
+        BUG_COMPONENT = component_gc
+for header in ('GCAnnotations.h', 'GCAPI.h', 'HeapAPI.h', 'RootingAPI.h', 'SliceBudget.h', 'SweepingAPI.h', 'TraceKind.h', 'TracingAPI.h', 'WeakMapPtr.h'):
+    with Files('../public/' + header):
+        BUG_COMPONENT = component_gc
+
+for stlfile in ['jsarray.*', 'jsbool*', 'jsdate.*', 'jsnum.*', 'json.*', 'jsstr.*']:
+    with Files(stlfile):
+        BUG_COMPONENT = component_stl
+
+with Files('builtin/Intl*'):
+    BUG_COMPONENT = component_intl
+with Files('builtin/make_intl_data.py'):
+    BUG_COMPONENT = component_intl
+
+with Files('../public/TrackedOptimizationInfo.h'):
+    BUG_COMPONENT = component_jit
+
+TEST_DIRS += ['jsapi-tests', 'tests', 'gdb']
\ No newline at end of file
diff --git a/js/src/jsapi-tests/moz.build b/js/src/jsapi-tests/moz.build
index 378b2ed7f..35bc69b85 100644
--- a/js/src/jsapi-tests/moz.build
+++ b/js/src/jsapi-tests/moz.build
@@ -3,6 +3,8 @@
 # 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/.
 
+include(../js-cxxflags.mozbuild)
+
 GeckoProgram('jsapi-tests', linkage=None)
 
 UNIFIED_SOURCES += [
@@ -142,12 +144,5 @@ USE_LIBS += [
 
 OS_LIBS += CONFIG['MOZ_ZLIB_LIBS']
 
-if CONFIG['GNU_CXX']:
-    CXXFLAGS += ['-Wno-shadow', '-Werror=format', '-fno-strict-aliasing']
-
-# This is intended as a temporary workaround to enable VS2015.
-if CONFIG['_MSC_VER']:
-    CXXFLAGS += ['-wd4312']
-
 DEFINES['topsrcdir'] = '%s/js/src' % TOPSRCDIR
 OBJDIR_PP_FILES.js.src['jsapi-tests'] += ['jsapi-tests-gdb.py.in']
diff --git a/js/src/moz.build b/js/src/moz.build
index 24ad2084e..b33965b66 100644
--- a/js/src/moz.build
+++ b/js/src/moz.build
@@ -3,65 +3,15 @@
 # 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/.
 
-# Directory metadata
-component_engine = ('Core', 'JavaScript Engine')
-component_gc     = ('Core', 'JavaScript: GC')
-component_intl   = ('Core', 'JavaScript: Internationalization API')
-component_jit    = ('Core', 'JavaScript Engine: JIT')
-component_stl    = ('Core', 'JavaScript: Standard Library')
-
-FILES_PER_UNIFIED_FILE = 6
-
-with Files('../public/**'):
-    BUG_COMPONENT = component_engine
-with Files('*'):
-    BUG_COMPONENT = component_engine
-
-with Files('wasm/**'):
-    BUG_COMPONENT = component_jit
-with Files('builtin/**'):
-    BUG_COMPONENT = component_stl
-with Files('ctypes/**'):
-    BUG_COMPONENT = ('Core', 'js-ctypes')
-with Files('gc/**'):
-    BUG_COMPONENT = component_gc
-with Files('jit/**'):
-    BUG_COMPONENT = component_jit
-
-# File-specific metadata
-for gcfile in ['jsgc*', 'devtools/rootAnalysis', 'devtools/gc-ubench', 'devtools/gctrace']:
-    with Files(gcfile):
-        BUG_COMPONENT = component_gc
-for header in ('GCAnnotations.h', 'GCAPI.h', 'HeapAPI.h', 'RootingAPI.h', 'SliceBudget.h', 'SweepingAPI.h', 'TraceKind.h', 'TracingAPI.h', 'WeakMapPtr.h'):
-    with Files('../public/' + header):
-        BUG_COMPONENT = component_gc
-
-for stlfile in ['jsarray.*', 'jsbool*', 'jsdate.*', 'jsnum.*', 'json.*', 'jsstr.*']:
-    with Files(stlfile):
-        BUG_COMPONENT = component_stl
-
-with Files('builtin/Intl*'):
-    BUG_COMPONENT = component_intl
-with Files('builtin/make_intl_data.py'):
-    BUG_COMPONENT = component_intl
-
-with Files('../public/TrackedOptimizationInfo.h'):
-    BUG_COMPONENT = component_jit
-
-
-if CONFIG['JS_BUNDLED_EDITLINE']:
-    DIRS += ['editline']
-
-if not CONFIG['JS_DISABLE_SHELL']:
-    DIRS += ['shell']
-
-TEST_DIRS += ['jsapi-tests', 'tests', 'gdb']
+include('js-config.mozbuild')
+include('js-cxxflags.mozbuild')
+include('js-testing.mozbuild')
 
 CONFIGURE_SUBST_FILES += [
-    'devtools/rootAnalysis/Makefile',
     'js-config',
     'js.pc',
 ]
+
 CONFIGURE_DEFINE_FILES += [
     'js-confdefs.h',
 ]
@@ -80,7 +30,6 @@ CONFIGURE_DEFINE_FILES += [
 
 if CONFIG['HAVE_DTRACE']:
     GENERATED_FILES += ['javascript-trace.h']
-
     EXPORTS += ['!javascript-trace.h']
 
 # Changes to internal header files, used externally, massively slow down
@@ -101,7 +50,6 @@ EXPORTS += [
     'jstypes.h',
     'jsversion.h',
     'jswrapper.h',
-    'perf/jsperf.h',
 ]
 
 # If you add a header here, add it to js/src/jsapi-tests/testIntTypesABI.cpp so
@@ -154,122 +102,33 @@ EXPORTS.js += [
     '../public/WeakMapPtr.h',
 ]
 
-SOURCES += [
-    'builtin/AtomicsObject.cpp',
-    'builtin/Eval.cpp',
-    'builtin/Intl.cpp',
-    'builtin/MapObject.cpp',
-    'builtin/ModuleObject.cpp',
-    'builtin/Object.cpp',
-    'builtin/Profilers.cpp',
-    'builtin/Promise.cpp',
-    'builtin/Reflect.cpp',
-    'builtin/ReflectParse.cpp',
-    'builtin/SIMD.cpp',
-    'builtin/SymbolObject.cpp',
-    'builtin/TestingFunctions.cpp',
-    'builtin/TypedObject.cpp',
-    'builtin/WeakMapObject.cpp',
-    'builtin/WeakSetObject.cpp',
-    'devtools/sharkctl.cpp',
-    'ds/LifoAlloc.cpp',
-    'ds/MemoryProtectionExceptionHandler.cpp',
-    'frontend/BytecodeCompiler.cpp',
-    'frontend/BytecodeEmitter.cpp',
-    'frontend/FoldConstants.cpp',
-    'frontend/NameFunctions.cpp',
-    'frontend/ParseNode.cpp',
-    'frontend/TokenStream.cpp',
-    'gc/Allocator.cpp',
-    'gc/Barrier.cpp',
-    'gc/GCTrace.cpp',
-    'gc/Iteration.cpp',
-    'gc/Marking.cpp',
-    'gc/Memory.cpp',
-    'gc/MemoryProfiler.cpp',
-    'gc/Nursery.cpp',
-    'gc/RootMarking.cpp',
-    'gc/Statistics.cpp',
-    'gc/Tracer.cpp',
-    'gc/Verifier.cpp',
-    'gc/Zone.cpp',
-    'irregexp/NativeRegExpMacroAssembler.cpp',
-    'irregexp/RegExpAST.cpp',
-    'irregexp/RegExpCharacters.cpp',
-    'irregexp/RegExpEngine.cpp',
-    'irregexp/RegExpInterpreter.cpp',
-    'irregexp/RegExpMacroAssembler.cpp',
-    'irregexp/RegExpParser.cpp',
-    'irregexp/RegExpStack.cpp',
-    'jit/AliasAnalysis.cpp',
-    'jit/AliasAnalysisShared.cpp',
-    'jit/AlignmentMaskAnalysis.cpp',
-    'jit/BacktrackingAllocator.cpp',
-    'jit/Bailouts.cpp',
-    'jit/BaselineBailouts.cpp',
-    'jit/BaselineCacheIR.cpp',
-    'jit/BaselineCompiler.cpp',
-    'jit/BaselineDebugModeOSR.cpp',
-    'jit/BaselineFrame.cpp',
-    'jit/BaselineFrameInfo.cpp',
-    'jit/BaselineIC.cpp',
-    'jit/BaselineInspector.cpp',
-    'jit/BaselineJIT.cpp',
-    'jit/BitSet.cpp',
-    'jit/BytecodeAnalysis.cpp',
-    'jit/C1Spewer.cpp',
-    'jit/CacheIR.cpp',
-    'jit/CodeGenerator.cpp',
-    'jit/CompileWrappers.cpp',
-    'jit/Disassembler.cpp',
-    'jit/EagerSimdUnbox.cpp',
-    'jit/EdgeCaseAnalysis.cpp',
-    'jit/EffectiveAddressAnalysis.cpp',
-    'jit/ExecutableAllocator.cpp',
-    'jit/FlowAliasAnalysis.cpp',
-    'jit/FoldLinearArithConstants.cpp',
-    'jit/InstructionReordering.cpp',
-    'jit/Ion.cpp',
-    'jit/IonAnalysis.cpp',
-    'jit/IonBuilder.cpp',
-    'jit/IonCaches.cpp',
-    'jit/IonOptimizationLevels.cpp',
-    'jit/JitcodeMap.cpp',
-    'jit/JitFrames.cpp',
-    'jit/JitOptions.cpp',
-    'jit/JitSpewer.cpp',
-    'jit/JSONSpewer.cpp',
-    'jit/LICM.cpp',
-    'jit/Linker.cpp',
-    'jit/LIR.cpp',
-    'jit/LoopUnroller.cpp',
-    'jit/Lowering.cpp',
-    'jit/MacroAssembler.cpp',
-    'jit/MCallOptimize.cpp',
-    'jit/MIR.cpp',
-    'jit/MIRGraph.cpp',
-    'jit/MoveResolver.cpp',
-    'jit/OptimizationTracking.cpp',
-    'jit/PerfSpewer.cpp',
-    'jit/ProcessExecutableMemory.cpp',
-    'jit/RangeAnalysis.cpp',
-    'jit/Recover.cpp',
-    'jit/RegisterAllocator.cpp',
-    'jit/RematerializedFrame.cpp',
-    'jit/Safepoints.cpp',
-    'jit/ScalarReplacement.cpp',
-    'jit/shared/BaselineCompiler-shared.cpp',
-    'jit/shared/CodeGenerator-shared.cpp',
-    'jit/shared/Lowering-shared.cpp',
-    'jit/SharedIC.cpp',
-    'jit/Sink.cpp',
-    'jit/Snapshots.cpp',
-    'jit/StupidAllocator.cpp',
-    'jit/TypedObjectPrediction.cpp',
-    'jit/TypePolicy.cpp',
-    'jit/ValueNumbering.cpp',
-    'jit/VMFunctions.cpp',
-    'jit/WasmBCE.cpp',
+DIRS += [
+    'builtin',
+    'devtools',
+    'ds',
+    'frontend',
+    'gc',
+    'irregexp',
+    'jit',
+    'perf',
+    'proxy',
+    'threading',
+    'wasm',
+]
+
+if CONFIG['JS_HAS_CTYPES']:
+    DIRS += ['ctypes']
+
+if CONFIG['JS_BUNDLED_EDITLINE']:
+    DIRS += ['editline']
+
+if not CONFIG['JS_DISABLE_SHELL']:
+    DIRS += ['shell']
+
+if CONFIG['MOZ_VTUNE']:
+    DIRS += ['vtune']
+
+UNIFIED_SOURCES += [
     'jsalloc.cpp',
     'jsapi.cpp',
     'jsbool.cpp',
@@ -291,16 +150,23 @@ SOURCES += [
     'jsscript.cpp',
     'jsstr.cpp',
     'jsweakmap.cpp',
-    'perf/jsperf.cpp',
-    'proxy/BaseProxyHandler.cpp',
-    'proxy/CrossCompartmentWrapper.cpp',
-    'proxy/DeadObjectProxy.cpp',
-    'proxy/OpaqueCrossCompartmentWrapper.cpp',
-    'proxy/Proxy.cpp',
-    'proxy/ScriptedProxyHandler.cpp',
-    'proxy/SecurityWrapper.cpp',
-    'proxy/Wrapper.cpp',
-    'threading/Mutex.cpp',
+]
+
+# Can't be built unified
+SOURCES += [
+    'jsarray.cpp',
+    'jsatom.cpp',
+    'jsdtoa.cpp',
+    'jsmath.cpp',
+    'jsutil.cpp',
+]
+
+# Suppress warnings in third-party code.
+# We are keeping this in the main moz.build because it is file specific
+if CONFIG['CLANG_CXX'] or CONFIG['GNU_CXX']:
+    SOURCES['jsdtoa.cpp'].flags += ['-Wno-implicit-fallthrough']
+
+UNIFIED_SOURCES += [
     'vm/ArgumentsObject.cpp',
     'vm/ArrayBufferObject.cpp',
     'vm/AsyncFunction.cpp',
@@ -359,273 +225,26 @@ SOURCES += [
     'vm/Value.cpp',
     'vm/WeakMapPtr.cpp',
     'vm/Xdr.cpp',
-    'wasm/AsmJS.cpp',
-    'wasm/WasmBaselineCompile.cpp',
-    'wasm/WasmBinaryFormat.cpp',
-    'wasm/WasmBinaryIterator.cpp',
-    'wasm/WasmBinaryToAST.cpp',
-    'wasm/WasmBinaryToExperimentalText.cpp',
-    'wasm/WasmBinaryToText.cpp',
-    'wasm/WasmCode.cpp',
-    'wasm/WasmCompartment.cpp',
-    'wasm/WasmCompile.cpp',
-    'wasm/WasmFrameIterator.cpp',
-    'wasm/WasmGenerator.cpp',
-    'wasm/WasmInstance.cpp',
-    'wasm/WasmIonCompile.cpp',
-    'wasm/WasmJS.cpp',
-    'wasm/WasmModule.cpp',
-    'wasm/WasmSignalHandlers.cpp',
-    'wasm/WasmStubs.cpp',
-    'wasm/WasmTable.cpp',
-    'wasm/WasmTextToBinary.cpp',
-    'wasm/WasmTextUtils.cpp',
-    'wasm/WasmTypes.cpp'
 ]
 
-# jsarray.cpp and jsatom.cpp cannot be built in unified mode because
-# xpcshell is broken during packaging when compiled with gcc-4.8.2
-# builtin/RegExp.cpp cannot be built in unified mode because it is built
-# without PGO
-# frontend/Parser.cpp cannot be built in unified mode because of explicit
-# template instantiations.
-# jsdtoa.cpp cannot be built in unified mode because we want to suppress
-# compiler warnings in third-party dtoa.c.
-# jsmath.cpp cannot be built in unified mode because it needs to pull rand_s
-# from <stdlib.h> on Windows through a preprocessor define.
-# jsutil.cpp cannot be built in unified mode because it is needed for
-# check-vanilla-allocations.
-# StoreBuffer.cpp cannot be built in unified because its template
-# instantiations may or may not be needed depending on what it gets bundled
-# with.
+# Can't be built unified
 SOURCES += [
-    'builtin/RegExp.cpp',
-    'frontend/Parser.cpp',
-    'gc/StoreBuffer.cpp',
-    'jsarray.cpp',
-    'jsatom.cpp',
-    'jsdtoa.cpp',
-    'jsmath.cpp',
-    'jsutil.cpp',
     'vm/Initialization.cpp',
 ]
 
 if CONFIG['JS_POSIX_NSPR']:
-    SOURCES += [
+    UNIFIED_SOURCES += [
         'vm/PosixNSPR.cpp',
     ]
 
-if CONFIG['MOZ_INSTRUMENTS']:
-    SOURCES += [
-        'devtools/Instruments.cpp',
-    ]
-
 if CONFIG['ENABLE_TRACE_LOGGING']:
+    # Can't be built unified
     SOURCES += [
         'vm/TraceLogging.cpp',
         'vm/TraceLoggingGraph.cpp',
         'vm/TraceLoggingTypes.cpp',
     ]
 
-if not CONFIG['ENABLE_ION']:
-    SOURCES += [
-        'jit/none/Trampoline-none.cpp'
-    ]
-elif CONFIG['JS_CODEGEN_X86'] or CONFIG['JS_CODEGEN_X64']:
-    SOURCES += [
-        'jit/x86-shared/Architecture-x86-shared.cpp',
-        'jit/x86-shared/Assembler-x86-shared.cpp',
-        'jit/x86-shared/AssemblerBuffer-x86-shared.cpp',
-        'jit/x86-shared/BaselineCompiler-x86-shared.cpp',
-        'jit/x86-shared/BaselineIC-x86-shared.cpp',
-        'jit/x86-shared/CodeGenerator-x86-shared.cpp',
-        'jit/x86-shared/Lowering-x86-shared.cpp',
-        'jit/x86-shared/MacroAssembler-x86-shared.cpp',
-        'jit/x86-shared/MoveEmitter-x86-shared.cpp',
-    ]
-    SOURCES += [
-        'jit/x86-shared/Disassembler-x86-shared.cpp',  # using namespace js::jit::X86Encoding;
-    ]
-    if CONFIG['JS_CODEGEN_X64']:
-        SOURCES += [
-            'jit/x64/Assembler-x64.cpp',
-            'jit/x64/Bailouts-x64.cpp',
-            'jit/x64/BaselineCompiler-x64.cpp',
-            'jit/x64/BaselineIC-x64.cpp',
-            'jit/x64/CodeGenerator-x64.cpp',
-            'jit/x64/Lowering-x64.cpp',
-            'jit/x64/MacroAssembler-x64.cpp',
-            'jit/x64/SharedIC-x64.cpp',
-            'jit/x64/Trampoline-x64.cpp',
-        ]
-    else:
-        SOURCES += [
-            'jit/x86/Assembler-x86.cpp',
-            'jit/x86/Bailouts-x86.cpp',
-            'jit/x86/BaselineCompiler-x86.cpp',
-            'jit/x86/BaselineIC-x86.cpp',
-            'jit/x86/CodeGenerator-x86.cpp',
-            'jit/x86/Lowering-x86.cpp',
-            'jit/x86/MacroAssembler-x86.cpp',
-            'jit/x86/SharedIC-x86.cpp',
-            'jit/x86/Trampoline-x86.cpp',
-        ]
-elif CONFIG['JS_CODEGEN_ARM']:
-    SOURCES += [
-        'jit/arm/Architecture-arm.cpp',
-        'jit/arm/Assembler-arm.cpp',
-        'jit/arm/Bailouts-arm.cpp',
-        'jit/arm/BaselineCompiler-arm.cpp',
-        'jit/arm/BaselineIC-arm.cpp',
-        'jit/arm/CodeGenerator-arm.cpp',
-        'jit/arm/disasm/Constants-arm.cpp',
-        'jit/arm/disasm/Disasm-arm.cpp',
-        'jit/arm/Lowering-arm.cpp',
-        'jit/arm/MacroAssembler-arm.cpp',
-        'jit/arm/MoveEmitter-arm.cpp',
-        'jit/arm/SharedIC-arm.cpp',
-        'jit/arm/Trampoline-arm.cpp',
-    ]
-    if CONFIG['JS_SIMULATOR_ARM']:
-        SOURCES += [
-            'jit/arm/Simulator-arm.cpp'
-        ]
-        # Configuration used only for testing.
-        if CONFIG['OS_ARCH'] == 'Linux' or CONFIG['OS_ARCH'] == 'Darwin':
-            CXXFLAGS += [ '-msse2', '-mfpmath=sse' ]
-    elif CONFIG['OS_ARCH'] == 'Darwin':
-        SOURCES += [
-            'jit/arm/llvm-compiler-rt/arm/aeabi_idivmod.S',
-            'jit/arm/llvm-compiler-rt/arm/aeabi_uidivmod.S',
-        ]
-elif CONFIG['JS_CODEGEN_ARM64']:
-    SOURCES += [
-        'jit/arm64/Architecture-arm64.cpp',
-        'jit/arm64/Assembler-arm64.cpp',
-        'jit/arm64/Bailouts-arm64.cpp',
-        'jit/arm64/BaselineIC-arm64.cpp',
-        'jit/arm64/CodeGenerator-arm64.cpp',
-        'jit/arm64/Lowering-arm64.cpp',
-        'jit/arm64/MacroAssembler-arm64.cpp',
-        'jit/arm64/MoveEmitter-arm64.cpp',
-        'jit/arm64/SharedIC-arm64.cpp',
-        'jit/arm64/Trampoline-arm64.cpp',
-        'jit/arm64/vixl/Assembler-vixl.cpp',
-        'jit/arm64/vixl/Cpu-vixl.cpp',
-        'jit/arm64/vixl/Decoder-vixl.cpp',
-        'jit/arm64/vixl/Disasm-vixl.cpp',
-        'jit/arm64/vixl/Instructions-vixl.cpp',
-        'jit/arm64/vixl/Instrument-vixl.cpp',
-        'jit/arm64/vixl/MacroAssembler-vixl.cpp',
-        'jit/arm64/vixl/MozAssembler-vixl.cpp',
-        'jit/arm64/vixl/MozInstructions-vixl.cpp',
-        'jit/arm64/vixl/Utils-vixl.cpp'
-    ]
-    if CONFIG['JS_SIMULATOR_ARM64']:
-        SOURCES += [
-            'jit/arm64/vixl/Debugger-vixl.cpp',
-            'jit/arm64/vixl/Logic-vixl.cpp',
-            'jit/arm64/vixl/MozSimulator-vixl.cpp',
-            'jit/arm64/vixl/Simulator-vixl.cpp'
-        ]
-elif CONFIG['JS_CODEGEN_MIPS32'] or CONFIG['JS_CODEGEN_MIPS64']:
-    SOURCES += [
-        'jit/mips-shared/Architecture-mips-shared.cpp',
-        'jit/mips-shared/Assembler-mips-shared.cpp',
-        'jit/mips-shared/Bailouts-mips-shared.cpp',
-        'jit/mips-shared/BaselineCompiler-mips-shared.cpp',
-        'jit/mips-shared/BaselineIC-mips-shared.cpp',
-        'jit/mips-shared/CodeGenerator-mips-shared.cpp',
-        'jit/mips-shared/Lowering-mips-shared.cpp',
-        'jit/mips-shared/MacroAssembler-mips-shared.cpp',
-        'jit/mips-shared/MoveEmitter-mips-shared.cpp',
-    ]
-    if CONFIG['JS_CODEGEN_MIPS32']:
-        SOURCES += [
-            'jit/mips32/Architecture-mips32.cpp',
-            'jit/mips32/Assembler-mips32.cpp',
-            'jit/mips32/Bailouts-mips32.cpp',
-            'jit/mips32/BaselineCompiler-mips32.cpp',
-            'jit/mips32/BaselineIC-mips32.cpp',
-            'jit/mips32/CodeGenerator-mips32.cpp',
-            'jit/mips32/Lowering-mips32.cpp',
-            'jit/mips32/MacroAssembler-mips32.cpp',
-            'jit/mips32/MoveEmitter-mips32.cpp',
-            'jit/mips32/SharedIC-mips32.cpp',
-            'jit/mips32/Trampoline-mips32.cpp',
-        ]
-        if CONFIG['JS_SIMULATOR_MIPS32']:
-            SOURCES += [
-                'jit/mips32/Simulator-mips32.cpp'
-            ]
-    elif CONFIG['JS_CODEGEN_MIPS64']:
-        SOURCES += [
-            'jit/mips64/Architecture-mips64.cpp',
-            'jit/mips64/Assembler-mips64.cpp',
-            'jit/mips64/Bailouts-mips64.cpp',
-            'jit/mips64/BaselineCompiler-mips64.cpp',
-            'jit/mips64/BaselineIC-mips64.cpp',
-            'jit/mips64/CodeGenerator-mips64.cpp',
-            'jit/mips64/Lowering-mips64.cpp',
-            'jit/mips64/MacroAssembler-mips64.cpp',
-            'jit/mips64/MoveEmitter-mips64.cpp',
-            'jit/mips64/SharedIC-mips64.cpp',
-            'jit/mips64/Trampoline-mips64.cpp',
-        ]
-        if CONFIG['JS_SIMULATOR_MIPS64']:
-            SOURCES += [
-                'jit/mips64/Simulator-mips64.cpp'
-            ]
-
-if CONFIG['OS_ARCH'] == 'WINNT':
-    SOURCES += [
-        'threading/windows/ConditionVariable.cpp',
-        'threading/windows/MutexImpl.cpp',
-        'threading/windows/Thread.cpp',
-    ]
-    # _CRT_RAND_S must be #defined before #including stdlib.h to get rand_s()
-    DEFINES['_CRT_RAND_S'] = True
-else:
-    SOURCES += [
-        'threading/posix/ConditionVariable.cpp',
-        'threading/posix/MutexImpl.cpp',
-        'threading/posix/Thread.cpp',
-    ]
-
-if CONFIG['JS_HAS_CTYPES']:
-    SOURCES += [
-        'ctypes/CTypes.cpp',
-        'ctypes/Library.cpp',
-    ]
-    if not CONFIG['MOZ_SYSTEM_FFI']:
-        LOCAL_INCLUDES += [
-            '!ctypes/libffi/include',
-            'ctypes/libffi/src/%s' % CONFIG['FFI_TARGET_DIR'],
-        ]
-
-if CONFIG['MOZ_VTUNE']:
-    SOURCES += [
-        'vtune/jitprofiling.c'
-    ]
-
-if CONFIG['HAVE_LINUX_PERF_EVENT_H']:
-    SOURCES += [
-        'perf/pm_linux.cpp'
-    ]
-    if CONFIG['LINUX_HEADERS_INCLUDES']:
-        SOURCES['perf/pm_linux.cpp'].flags += [CONFIG['LINUX_HEADERS_INCLUDES']]
-else:
-    SOURCES += [
-        'perf/pm_stub.cpp'
-    ]
-
-GENERATED_FILES += ['frontend/ReservedWordsGenerated.h']
-ReservedWordsGenerated = GENERATED_FILES['frontend/ReservedWordsGenerated.h']
-ReservedWordsGenerated.script = 'frontend/GenerateReservedWords.py'
-ReservedWordsGenerated.inputs += [
-    'frontend/ReservedWords.h'
-]
-
 # JavaScript must be built shared, even for static builds, as it is used by
 # other modules which are always built shared. Failure to do so results in
 # the js code getting copied into xpinstall and jsd as well as mozilla-bin,
@@ -661,65 +280,14 @@ USE_LIBS += [
     'zlib',
 ]
 
-if CONFIG['NIGHTLY_BUILD']:
-    DEFINES['ENABLE_BINARYDATA'] = True
-
-if CONFIG['NIGHTLY_BUILD']:
-    DEFINES['ENABLE_SIMD'] = True
-
-# Also set in shell/moz.build
-DEFINES['ENABLE_SHARED_ARRAY_BUFFER'] = True
-
-DEFINES['EXPORT_JS_API'] = True
-
-if CONFIG['JS_HAS_CTYPES']:
-    DEFINES['JS_HAS_CTYPES'] = True
-    for var in ('DLL_PREFIX', 'DLL_SUFFIX'):
-        DEFINES[var] = '"%s"' % CONFIG[var]
-
-if CONFIG['MOZ_LINKER']:
-    DEFINES['MOZ_LINKER'] = True
-
-if CONFIG['_MSC_VER']:
-    if CONFIG['CPU_ARCH'] == 'x86':
-        SOURCES['builtin/RegExp.cpp'].no_pgo = True # Bug 772303
-    elif CONFIG['CPU_ARCH'] == 'x86_64' and CONFIG['JS_HAS_CTYPES']:
-        SOURCES['ctypes/CTypes.cpp'].no_pgo = True # Bug 810661
-    # Prevent floating point errors caused by VC++ optimizations
-    CFLAGS += ['-fp:precise']
-    CXXFLAGS += ['-fp:precise']    
-    # C4805 warns mixing bool with other integral types in computation.
-    # But given the conversion from bool is specified, and this is a
-    # pattern widely used in code in js/src, suppress this warning here.
-    CXXFLAGS += ['-wd4805']
-    # C4661 ("no suitable definition provided for explicit template
-    # instantiation request") is emitted for all Parser methods that
-    # have a Parser<FullParseHandler> definition but no
-    # Parser<SyntaxParseHandler> definition, see bug 1167030.
-    CXXFLAGS += ['-wd4661']
-    CXXFLAGS += ['-we4067', '-we4258', '-we4275']
-    CXXFLAGS += ['-wd4146'] # FIXME: unary minus operator applied to unsigned type (bug 1229189)
-
-    # This is intended as a temporary hack to support building with VS2015.
-    # 'noexcept' used with no exception handling mode specified;
-    # termination on exception is not guaranteed. Specify /EHsc
-    CXXFLAGS += ['-wd4577']
-    CXXFLAGS += ['-wd4312']
-
 if CONFIG['OS_ARCH'] not in ('WINNT'):
-    OS_LIBS += [
-        'm',
-    ]
+    OS_LIBS += ['m']
 
 if CONFIG['OS_ARCH'] == 'FreeBSD':
-    OS_LIBS += [
-        '-pthread',
-    ]
+    OS_LIBS += ['-pthread']
 
 if CONFIG['OS_ARCH'] == 'Linux':
-    OS_LIBS += [
-        'dl',
-    ]
+    OS_LIBS += ['dl']
 
 if CONFIG['OS_ARCH'] == 'SunOS':
     OS_LIBS += [
@@ -731,65 +299,8 @@ if CONFIG['OS_ARCH'] == 'SunOS':
 
 OS_LIBS += CONFIG['REALTIME_LIBS']
 
-CFLAGS += CONFIG['MOZ_ICU_CFLAGS']
-CXXFLAGS += CONFIG['MOZ_ICU_CFLAGS']
-
 NO_EXPAND_LIBS = True
 
 DIST_INSTALL = True
 
-# Prepare self-hosted JS code for embedding
-GENERATED_FILES += [('selfhosted.out.h', 'selfhosted.js')]
-selfhosted = GENERATED_FILES[('selfhosted.out.h', 'selfhosted.js')]
-selfhosted.script = 'builtin/embedjs.py:generate_selfhosted'
-selfhosted.inputs = [
-    'js.msg',
-    'builtin/TypedObjectConstants.h',
-    'builtin/SelfHostingDefines.h',
-    'builtin/Utilities.js',
-    'builtin/Array.js',
-    'builtin/AsyncIteration.js',
-    'builtin/Classes.js',
-    'builtin/Date.js',
-    'builtin/Error.js',
-    'builtin/Function.js',
-    'builtin/Generator.js',
-    'builtin/Intl.js',
-    'builtin/IntlData.js',
-    'builtin/Iterator.js',
-    'builtin/Map.js',
-    'builtin/Module.js',
-    'builtin/Number.js',
-    'builtin/Object.js',
-    'builtin/Promise.js',
-    'builtin/Reflect.js',
-    'builtin/RegExp.js',
-    'builtin/RegExpGlobalReplaceOpt.h.js',
-    'builtin/RegExpLocalReplaceOpt.h.js',
-    'builtin/String.js',
-    'builtin/Set.js',
-    'builtin/Sorting.js',
-    'builtin/TypedArray.js',
-    'builtin/TypedObject.js',
-    'builtin/WeakMap.js',
-    'builtin/WeakSet.js'
-]
 
-if CONFIG['JS_HAS_CTYPES']:
-    if CONFIG['MOZ_SYSTEM_FFI']:
-        CXXFLAGS += CONFIG['MOZ_FFI_CFLAGS']
-    else:
-        # Windows needs this to be linked with a static library.
-        DEFINES['FFI_BUILDING'] = True
-
-if CONFIG['GNU_CXX']:
-    # Disable strict-aliasing for GCC, which is enabled by default
-    # starting with version 7.1, see Mozilla bug 1363009.
-    CXXFLAGS += ['-Wno-shadow', '-Werror=format', '-fno-strict-aliasing']
-
-# Suppress warnings in third-party code.
-if CONFIG['CLANG_CXX'] or CONFIG['GNU_CXX']:
-    SOURCES['jsdtoa.cpp'].flags += ['-Wno-implicit-fallthrough']
-
-if CONFIG['OS_ARCH'] == 'WINNT':
-    DEFINES['NOMINMAX'] = True
diff --git a/js/src/perf/moz.build b/js/src/perf/moz.build
new file mode 100644
index 000000000..f0dd7e1d6
--- /dev/null
+++ b/js/src/perf/moz.build
@@ -0,0 +1,29 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# 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/.
+
+include('../js-config.mozbuild')
+include('../js-cxxflags.mozbuild')
+
+FINAL_LIBRARY = "js"
+
+# Includes should be relative to parent path
+LOCAL_INCLUDES += ["!..", ".."]
+
+EXPORTS += ['jsperf.h']
+
+SOURCES += [
+    'jsperf.cpp',
+]
+
+if CONFIG['HAVE_LINUX_PERF_EVENT_H']:
+    SOURCES += [
+        'pm_linux.cpp'
+    ]
+    if CONFIG['LINUX_HEADERS_INCLUDES']:
+        SOURCES['pm_linux.cpp'].flags += [CONFIG['LINUX_HEADERS_INCLUDES']]
+else:
+    SOURCES += [
+        'pm_stub.cpp'
+    ]
\ No newline at end of file
diff --git a/js/src/proxy/moz.build b/js/src/proxy/moz.build
new file mode 100644
index 000000000..72082df85
--- /dev/null
+++ b/js/src/proxy/moz.build
@@ -0,0 +1,23 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# 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/.
+
+include('../js-config.mozbuild')
+include('../js-cxxflags.mozbuild')
+
+FINAL_LIBRARY = "js"
+
+# Includes should be relative to parent path
+LOCAL_INCLUDES += ["!..", ".."]
+
+SOURCES += [
+    'BaseProxyHandler.cpp',
+    'CrossCompartmentWrapper.cpp',
+    'DeadObjectProxy.cpp',
+    'OpaqueCrossCompartmentWrapper.cpp',
+    'Proxy.cpp',
+    'ScriptedProxyHandler.cpp',
+    'SecurityWrapper.cpp',
+    'Wrapper.cpp',
+]
diff --git a/js/src/shell/moz.build b/js/src/shell/moz.build
index 7c861fb0d..93812da74 100644
--- a/js/src/shell/moz.build
+++ b/js/src/shell/moz.build
@@ -3,6 +3,8 @@
 # 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/.
 
+include('../js-cxxflags.mozbuild')
+
 if CONFIG['JS_SHELL_NAME']:
     GeckoProgram(CONFIG['JS_SHELL_NAME'], linkage=None)
     if CONFIG['JS_BUNDLED_EDITLINE']:
@@ -49,13 +51,6 @@ shellmoduleloader.inputs = [
     'ModuleLoader.js',
 ]
 
-if CONFIG['GNU_CXX']:
-    CXXFLAGS += ['-Wno-shadow', '-Werror=format']
-
-# This is intended as a temporary workaround to enable VS2015.
-if CONFIG['_MSC_VER']:
-    CXXFLAGS += ['-wd4312']
-
 # Place a GDB Python auto-load file next to the shell executable, both in
 # the build directory and in the dist/bin directory.
 DEFINES['topsrcdir'] = '%s/js/src' % TOPSRCDIR
diff --git a/js/src/threading/moz.build b/js/src/threading/moz.build
new file mode 100644
index 000000000..97673d0c6
--- /dev/null
+++ b/js/src/threading/moz.build
@@ -0,0 +1,30 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# 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/.
+
+include('../js-config.mozbuild')
+include('../js-cxxflags.mozbuild')
+
+FINAL_LIBRARY = "js"
+
+# Includes should be relative to parent path
+LOCAL_INCLUDES += ["!..", ".."]
+
+SOURCES += [
+    'Mutex.cpp',
+]
+
+if CONFIG['OS_ARCH'] == 'WINNT':
+    SOURCES += [
+        'windows/ConditionVariable.cpp',
+        'windows/MutexImpl.cpp',
+        'windows/Thread.cpp',
+    ]
+    # _CRT_RAND_S must be #defined before #including stdlib.h to get rand_s()
+else:
+    SOURCES += [
+        'posix/ConditionVariable.cpp',
+        'posix/MutexImpl.cpp',
+        'posix/Thread.cpp',
+    ]
\ No newline at end of file
diff --git a/js/src/vm/SelfHosting.cpp b/js/src/vm/SelfHosting.cpp
index b7d62efc1..dc1dfb9fa 100644
--- a/js/src/vm/SelfHosting.cpp
+++ b/js/src/vm/SelfHosting.cpp
@@ -20,8 +20,8 @@
 #include "jsstr.h"
 #include "jsweakmap.h"
 #include "jswrapper.h"
-#include "selfhosted.out.h"
 
+#include "builtin/selfhosted.out.h"
 #include "builtin/Intl.h"
 #include "builtin/MapObject.h"
 #include "builtin/ModuleObject.h"
diff --git a/js/src/vtune/moz.build b/js/src/vtune/moz.build
new file mode 100644
index 000000000..465919795
--- /dev/null
+++ b/js/src/vtune/moz.build
@@ -0,0 +1,14 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# 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/.
+
+include('../js-config.mozbuild')
+include('../js-cxxflags.mozbuild')
+
+FINAL_LIBRARY = "js"
+
+# Includes should be relative to parent path
+LOCAL_INCLUDES += ["!..", ".."]
+
+SOURCES += ['jitprofiling.c']
\ No newline at end of file
diff --git a/js/src/wasm/moz.build b/js/src/wasm/moz.build
new file mode 100644
index 000000000..5fe046add
--- /dev/null
+++ b/js/src/wasm/moz.build
@@ -0,0 +1,39 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# 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/.
+
+include('../js-config.mozbuild')
+include('../js-cxxflags.mozbuild')
+
+FINAL_LIBRARY = "js"
+
+# Includes should be relative to parent path
+LOCAL_INCLUDES += ["!..", ".."]
+
+UNIFIED_SOURCES += [
+    'AsmJS.cpp',
+    'WasmBaselineCompile.cpp',
+    'WasmBinaryFormat.cpp',
+    'WasmBinaryToAST.cpp',
+    'WasmBinaryToExperimentalText.cpp',
+    'WasmBinaryToText.cpp',
+    'WasmCode.cpp',
+    'WasmCompartment.cpp',
+    'WasmCompile.cpp',
+    'WasmFrameIterator.cpp',
+    'WasmGenerator.cpp',
+    'WasmInstance.cpp',
+    'WasmIonCompile.cpp',
+    'WasmJS.cpp',
+    'WasmModule.cpp',
+    'WasmSignalHandlers.cpp',
+    'WasmStubs.cpp',
+    'WasmTable.cpp',
+    'WasmTextToBinary.cpp',
+    'WasmTextUtils.cpp',
+    'WasmTypes.cpp'
+]
+
+if CONFIG['MOZ_DEBUG']:
+    SOURCES += ['WasmBinaryIterator.cpp']
\ No newline at end of file