diff --git a/src/wasm/wasm-js.cc b/src/wasm/wasm-js.cc
new file mode 100644
index 0000000..80d8bdb
--- /dev/null
+++ b/src/wasm/wasm-js.cc
@@ -0,0 +1,345 @@
+// Copyright 2015 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "src/api.h"
+#include "src/api-natives.h"
+#include "src/assert-scope.h"
+#include "src/ast/ast.h"
+#include "src/ast/scopes.h"
+#include "src/factory.h"
+#include "src/handles.h"
+#include "src/isolate.h"
+#include "src/objects.h"
+#include "src/parsing/parser.h"
+#include "src/typing-asm.h"
+
+#include "src/wasm/asm-wasm-builder.h"
+#include "src/wasm/encoder.h"
+#include "src/wasm/module-decoder.h"
+#include "src/wasm/wasm-js.h"
+#include "src/wasm/wasm-module.h"
+#include "src/wasm/wasm-result.h"
+
+typedef uint8_t byte;
+
+using v8::internal::wasm::ErrorThrower;
+
+namespace v8 {
+
+namespace {
+struct RawBuffer {
+  const byte* start;
+  const byte* end;
+  size_t size() { return static_cast<size_t>(end - start); }
+};
+
+
+RawBuffer GetRawBufferArgument(
+    ErrorThrower& thrower, const v8::FunctionCallbackInfo<v8::Value>& args) {
+  if (args.Length() < 1 || !args[0]->IsArrayBuffer()) {
+    thrower.Error("Argument 0 must be an array buffer");
+    return {nullptr, nullptr};
+  }
+  Local<ArrayBuffer> buffer = Local<ArrayBuffer>::Cast(args[0]);
+  ArrayBuffer::Contents contents = buffer->GetContents();
+
+  // TODO(titzer): allow offsets into buffers, views, etc.
+
+  const byte* start = reinterpret_cast<const byte*>(contents.Data());
+  const byte* end = start + contents.ByteLength();
+
+  if (start == nullptr) {
+    thrower.Error("ArrayBuffer argument is empty");
+  }
+  return {start, end};
+}
+
+
+void VerifyModule(const v8::FunctionCallbackInfo<v8::Value>& args) {
+  HandleScope scope(args.GetIsolate());
+  i::Isolate* isolate = reinterpret_cast<i::Isolate*>(args.GetIsolate());
+  ErrorThrower thrower(isolate, "WASM.verifyModule()");
+
+  RawBuffer buffer = GetRawBufferArgument(thrower, args);
+  if (thrower.error()) return;
+
+  i::Zone zone;
+  internal::wasm::ModuleResult result = internal::wasm::DecodeWasmModule(
+      isolate, &zone, buffer.start, buffer.end, true, false);
+
+  if (result.failed()) {
+    thrower.Failed("", result);
+  }
+
+  if (result.val) delete result.val;
+}
+
+
+void VerifyFunction(const v8::FunctionCallbackInfo<v8::Value>& args) {
+  HandleScope scope(args.GetIsolate());
+  i::Isolate* isolate = reinterpret_cast<i::Isolate*>(args.GetIsolate());
+  ErrorThrower thrower(isolate, "WASM.verifyFunction()");
+
+  RawBuffer buffer = GetRawBufferArgument(thrower, args);
+  if (thrower.error()) return;
+
+  internal::wasm::FunctionResult result;
+  {
+    // Verification of a single function shouldn't allocate.
+    i::DisallowHeapAllocation no_allocation;
+    i::Zone zone;
+    result = internal::wasm::DecodeWasmFunction(isolate, &zone, nullptr,
+                                                buffer.start, buffer.end);
+  }
+
+  if (result.failed()) {
+    thrower.Failed("", result);
+  }
+
+  if (result.val) delete result.val;
+}
+
+
+void CompileRun(const v8::FunctionCallbackInfo<v8::Value>& args) {
+  HandleScope scope(args.GetIsolate());
+  i::Isolate* isolate = reinterpret_cast<i::Isolate*>(args.GetIsolate());
+  ErrorThrower thrower(isolate, "WASM.compileRun()");
+
+  RawBuffer buffer = GetRawBufferArgument(thrower, args);
+  if (thrower.error()) return;
+
+  // Decode and pre-verify the functions before compiling and running.
+  i::Zone zone;
+  internal::wasm::ModuleResult result = internal::wasm::DecodeWasmModule(
+      isolate, &zone, buffer.start, buffer.end, true, false);
+
+  if (result.failed()) {
+    thrower.Failed("", result);
+  } else {
+    // Success. Compile and run!
+    int32_t retval = i::wasm::CompileAndRunWasmModule(isolate, result.val);
+    args.GetReturnValue().Set(retval);
+  }
+
+  if (result.val) delete result.val;
+}
+
+
+v8::internal::wasm::WasmModuleIndex* TranslateAsmModule(i::ParseInfo* info) {
+  info->set_global();
+  info->set_lazy(false);
+  info->set_allow_lazy_parsing(false);
+  info->set_toplevel(true);
+
+  if (!i::Compiler::ParseAndAnalyze(info)) {
+    return nullptr;
+  }
+
+  info->set_literal(
+      info->scope()->declarations()->at(0)->AsFunctionDeclaration()->fun());
+
+  v8::internal::AsmTyper typer(info->isolate(), info->zone(), *(info->script()),
+                               info->literal());
+  if (!typer.Validate()) {
+    return nullptr;
+  }
+
+  auto module = v8::internal::wasm::AsmWasmBuilder(
+                    info->isolate(), info->zone(), info->literal())
+                    .Run();
+  return module;
+}
+
+
+void AsmCompileRun(const v8::FunctionCallbackInfo<v8::Value>& args) {
+  HandleScope scope(args.GetIsolate());
+  i::Isolate* isolate = reinterpret_cast<i::Isolate*>(args.GetIsolate());
+  ErrorThrower thrower(isolate, "WASM.asmCompileRun()");
+
+  if (args.Length() != 1) {
+    thrower.Error("Invalid argument count");
+    return;
+  }
+  if (!args[0]->IsString()) {
+    thrower.Error("Invalid argument count");
+    return;
+  }
+
+  i::Factory* factory = isolate->factory();
+  i::Zone zone;
+  Local<String> source = Local<String>::Cast(args[0]);
+  i::Handle<i::Script> script = factory->NewScript(Utils::OpenHandle(*source));
+  i::ParseInfo info(&zone, script);
+
+  auto module = TranslateAsmModule(&info);
+  if (module == nullptr) {
+    thrower.Error("Asm.js validation failed");
+    return;
+  }
+
+  int32_t result = v8::internal::wasm::CompileAndRunWasmModule(
+      isolate, module->Begin(), module->End(), true);
+  args.GetReturnValue().Set(result);
+}
+
+
+// TODO(aseemgarg): deal with arraybuffer and foreign functions
+void InstantiateModuleFromAsm(const v8::FunctionCallbackInfo<v8::Value>& args) {
+  HandleScope scope(args.GetIsolate());
+  i::Isolate* isolate = reinterpret_cast<i::Isolate*>(args.GetIsolate());
+  ErrorThrower thrower(isolate, "WASM.instantiateModuleFromAsm()");
+
+  if (args.Length() != 1) {
+    thrower.Error("Invalid argument count");
+    return;
+  }
+  if (!args[0]->IsString()) {
+    thrower.Error("Invalid argument count");
+    return;
+  }
+
+  i::Factory* factory = isolate->factory();
+  i::Zone zone;
+  Local<String> source = Local<String>::Cast(args[0]);
+  i::Handle<i::Script> script = factory->NewScript(Utils::OpenHandle(*source));
+  i::ParseInfo info(&zone, script);
+
+  auto module = TranslateAsmModule(&info);
+  if (module == nullptr) {
+    thrower.Error("Asm.js validation failed");
+    return;
+  }
+
+  i::Handle<i::JSArrayBuffer> memory = i::Handle<i::JSArrayBuffer>::null();
+  internal::wasm::ModuleResult result = internal::wasm::DecodeWasmModule(
+      isolate, &zone, module->Begin(), module->End(), false, false);
+
+  if (result.failed()) {
+    thrower.Failed("", result);
+  } else {
+    // Success. Instantiate the module and return the object.
+    i::Handle<i::JSObject> ffi = i::Handle<i::JSObject>::null();
+
+    i::MaybeHandle<i::JSObject> object =
+        result.val->Instantiate(isolate, ffi, memory);
+
+    if (!object.is_null()) {
+      args.GetReturnValue().Set(v8::Utils::ToLocal(object.ToHandleChecked()));
+    }
+  }
+
+  if (result.val) delete result.val;
+}
+
+
+void InstantiateModule(const v8::FunctionCallbackInfo<v8::Value>& args) {
+  HandleScope scope(args.GetIsolate());
+  i::Isolate* isolate = reinterpret_cast<i::Isolate*>(args.GetIsolate());
+  ErrorThrower thrower(isolate, "WASM.instantiateModule()");
+
+  RawBuffer buffer = GetRawBufferArgument(thrower, args);
+  if (buffer.start == nullptr) return;
+
+  i::Handle<i::JSArrayBuffer> memory = i::Handle<i::JSArrayBuffer>::null();
+  if (args.Length() > 2 && args[2]->IsArrayBuffer()) {
+    Local<Object> obj = Local<Object>::Cast(args[2]);
+    i::Handle<i::Object> mem_obj = v8::Utils::OpenHandle(*obj);
+    memory = i::Handle<i::JSArrayBuffer>(i::JSArrayBuffer::cast(*mem_obj));
+  }
+
+  // Decode but avoid a redundant pass over function bodies for verification.
+  // Verification will happen during compilation.
+  i::Zone zone;
+  internal::wasm::ModuleResult result = internal::wasm::DecodeWasmModule(
+      isolate, &zone, buffer.start, buffer.end, false, false);
+
+  if (result.failed()) {
+    thrower.Failed("", result);
+  } else {
+    // Success. Instantiate the module and return the object.
+    i::Handle<i::JSObject> ffi = i::Handle<i::JSObject>::null();
+    if (args.Length() > 1 && args[1]->IsObject()) {
+      Local<Object> obj = Local<Object>::Cast(args[1]);
+      ffi = i::Handle<i::JSObject>::cast(v8::Utils::OpenHandle(*obj));
+    }
+
+    i::MaybeHandle<i::JSObject> object =
+        result.val->Instantiate(isolate, ffi, memory);
+
+    if (!object.is_null()) {
+      args.GetReturnValue().Set(v8::Utils::ToLocal(object.ToHandleChecked()));
+    }
+  }
+
+  if (result.val) delete result.val;
+}
+}  // namespace
+
+
+// TODO(titzer): we use the API to create the function template because the
+// internal guts are too ugly to replicate here.
+static i::Handle<i::FunctionTemplateInfo> NewTemplate(i::Isolate* i_isolate,
+                                                      FunctionCallback func) {
+  Isolate* isolate = reinterpret_cast<Isolate*>(i_isolate);
+  Local<FunctionTemplate> local = FunctionTemplate::New(isolate, func);
+  return v8::Utils::OpenHandle(*local);
+}
+
+
+namespace internal {
+static Handle<String> v8_str(Isolate* isolate, const char* str) {
+  return isolate->factory()->NewStringFromAsciiChecked(str);
+}
+
+
+static void InstallFunc(Isolate* isolate, Handle<JSObject> object,
+                        const char* str, FunctionCallback func) {
+  Handle<String> name = v8_str(isolate, str);
+  Handle<FunctionTemplateInfo> temp = NewTemplate(isolate, func);
+  Handle<JSFunction> function =
+      ApiNatives::InstantiateFunction(temp).ToHandleChecked();
+  PropertyAttributes attributes =
+      static_cast<PropertyAttributes>(DONT_DELETE | READ_ONLY);
+  JSObject::AddProperty(object, name, function, attributes);
+}
+
+
+void WasmJs::Install(Isolate* isolate, Handle<JSGlobalObject> global) {
+  // Setup wasm function map.
+  Handle<Context> context(global->native_context(), isolate);
+  InstallWasmFunctionMap(isolate, context);
+
+  // Bind the WASM object.
+  Factory* factory = isolate->factory();
+  Handle<String> name = v8_str(isolate, "_WASMEXP_");
+  Handle<JSFunction> cons = factory->NewFunction(name);
+  JSFunction::SetInstancePrototype(
+      cons, Handle<Object>(context->initial_object_prototype(), isolate));
+  cons->shared()->set_instance_class_name(*name);
+  Handle<JSObject> wasm_object = factory->NewJSObject(cons, TENURED);
+  PropertyAttributes attributes = static_cast<PropertyAttributes>(DONT_ENUM);
+  JSObject::AddProperty(global, name, wasm_object, attributes);
+
+  // Install functions on the WASM object.
+  InstallFunc(isolate, wasm_object, "instantiateModule", InstantiateModule);
+  InstallFunc(isolate, wasm_object, "verifyModule", VerifyModule);
+  InstallFunc(isolate, wasm_object, "verifyFunction", VerifyFunction);
+  InstallFunc(isolate, wasm_object, "compileRun", CompileRun);
+  InstallFunc(isolate, wasm_object, "asmCompileRun", AsmCompileRun);
+  InstallFunc(isolate, wasm_object, "instantiateModuleFromAsm",
+              InstantiateModuleFromAsm);
+}
+
+
+void WasmJs::InstallWasmFunctionMap(Isolate* isolate, Handle<Context> context) {
+  if (!context->get(Context::WASM_FUNCTION_MAP_INDEX)->IsMap()) {
+    Handle<Map> wasm_function_map = isolate->factory()->NewMap(
+        JS_FUNCTION_TYPE, JSFunction::kSize + kPointerSize);
+    wasm_function_map->set_is_callable();
+    context->set_wasm_function_map(*wasm_function_map);
+  }
+}
+
+}  // namespace internal
+}  // namespace v8