[ffi] Translation + test for int32

src/ffi/ffi-compiler.h

 // Copyright 2017 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.
 
 #ifndef SRC_FFI_FFI_COMPILER_H_
 #define SRC_FFI_FFI_COMPILER_H_
 
 #include "src/code-stub-assembler.h"
 #include "src/machine-type.h"
 
 namespace v8 {
 namespace internal {
 
 typedef compiler::Node Node;
 typedef compiler::CodeAssemblerState CodeAssemblerState;
 
 void InstallFFIMap(Isolate* isolate);
 
 namespace ffi {
 
-typedef Signature<MachineType> FFISignature;
+enum class FFIType : uint8_t { kInt32 };
+
+typedef Signature<FFIType> FFISignature;
 
 struct NativeFunction {
   FFISignature* sig;
   uint8_t* start;
 };
 
 Handle<JSFunction> CompileJSToNativeWrapper(Isolate* isolate,
                                             Handle<String> name,
                                             NativeFunction func);
 }  // namespace ffi
 }  // namespace internal
 }  // namespace v8
 
 #endif  // SRC_FFI_FFI_COMPILER_H_