Add command line flags to dump asm.js -> wasm conversion data.

src/wasm/wasm-js.cc

 // 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"
@@ skipping 108 matching lines @@
     typer.set_allow_simd(true);
   }
   if (!typer.Validate()) {
     thrower->Error("Asm.js validation failed: %s", typer.error_message());
     return nullptr;
   }
 
   auto module = v8::internal::wasm::AsmWasmBuilder(
                     info->isolate(), info->zone(), info->literal(), foreign)
                     .Run();
+
+  if (i::FLAG_dump_asmjs_wasm) {
+    FILE* wasm_file = fopen(i::FLAG_asmjs_wasm_dumpfile, "wb");
+    if (wasm_file) {
+      fwrite(module->Begin(), module->End() - module->Begin(), 1, wasm_file);
+      fclose(wasm_file);
+    }
+  }
+
   return module;
 }
 
 
 void InstantiateModuleCommon(const v8::FunctionCallbackInfo<v8::Value>& args,
                              const byte* start, const byte* end,
                              ErrorThrower* thrower, bool must_decode) {
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(args.GetIsolate());
 
   i::Handle<i::JSArrayBuffer> memory = i::Handle<i::JSArrayBuffer>::null();
@@ skipping 134 matching lines @@
   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