Allow asm modules to be instatiated with external heaps.

src/wasm/wasm-js.cc

Index: src/wasm/wasm-js.cc
diff --git a/src/wasm/wasm-js.cc b/src/wasm/wasm-js.cc
index 80d8bdb2369e1b87e4fbf3427c19660f4a3e3bb6..7944a621e677e65796d9a50100913e783be1b5d1 100644
--- a/src/wasm/wasm-js.cc
+++ b/src/wasm/wasm-js.cc
@@ -126,7 +126,8 @@ void CompileRun(const v8::FunctionCallbackInfo<v8::Value>& args) {
 }
 
 
-v8::internal::wasm::WasmModuleIndex* TranslateAsmModule(i::ParseInfo* info) {
+v8::internal::wasm::WasmModuleIndex* TranslateAsmModule(i::ParseInfo* info,
+                                                        ErrorThrower* thrower) {
   info->set_global();
   info->set_lazy(false);
   info->set_allow_lazy_parsing(false);
@@ -142,6 +143,7 @@ v8::internal::wasm::WasmModuleIndex* TranslateAsmModule(i::ParseInfo* info) {
   v8::internal::AsmTyper typer(info->isolate(), info->zone(), *(info->script()),
                                info->literal());
   if (!typer.Validate()) {
+    thrower->Error("Asm.js validation failed: %s", typer.error_message());
     return nullptr;
   }
 
@@ -162,7 +164,7 @@ void AsmCompileRun(const v8::FunctionCallbackInfo<v8::Value>& args) {
     return;
   }
   if (!args[0]->IsString()) {
-    thrower.Error("Invalid argument count");
+    thrower.Error("Asm module text should be a string");
     return;
   }
 
@@ -172,9 +174,8 @@ void AsmCompileRun(const v8::FunctionCallbackInfo<v8::Value>& args) {
   i::Handle<i::Script> script = factory->NewScript(Utils::OpenHandle(*source));
   i::ParseInfo info(&zone, script);
 
-  auto module = TranslateAsmModule(&info);
+  auto module = TranslateAsmModule(&info, &thrower);
   if (module == nullptr) {
-    thrower.Error("Asm.js validation failed");
     return;
   }
 
@@ -184,42 +185,35 @@ void AsmCompileRun(const v8::FunctionCallbackInfo<v8::Value>& args) {
 }
 
 
-// TODO(aseemgarg): deal with arraybuffer and foreign functions
-void InstantiateModuleFromAsm(const v8::FunctionCallbackInfo<v8::Value>& args) {
-  HandleScope scope(args.GetIsolate());
+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());
-  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::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));
   }
 
-  i::Factory* factory = isolate->factory();
+  // Decode but avoid a redundant pass over function bodies for verification.
+  // Verification will happen during compilation.
   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);
+      isolate, &zone, start, end, false, false);
 
-  if (result.failed()) {
-    thrower.Failed("", result);
+  if (result.failed() && must_decode) {
+    thrower->Error("Asm.js converted module failed to decode");
+  } else 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);
@@ -233,46 +227,40 @@ void InstantiateModuleFromAsm(const v8::FunctionCallbackInfo<v8::Value>& args) {
 }
 
 
-void InstantiateModule(const v8::FunctionCallbackInfo<v8::Value>& args) {
+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.instantiateModule()");
-
-  RawBuffer buffer = GetRawBufferArgument(thrower, args);
-  if (buffer.start == nullptr) return;
+  ErrorThrower thrower(isolate, "WASM.instantiateModuleFromAsm()");
 
-  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));
+  if (!args[0]->IsString()) {
+    thrower.Error("Asm module text should be a string");
+    return;
   }
 
-  // Decode but avoid a redundant pass over function bodies for verification.
-  // Verification will happen during compilation.
+  i::Factory* factory = isolate->factory();
   i::Zone zone;
-  internal::wasm::ModuleResult result = internal::wasm::DecodeWasmModule(
-      isolate, &zone, buffer.start, buffer.end, false, false);
+  Local<String> source = Local<String>::Cast(args[0]);
+  i::Handle<i::Script> script = factory->NewScript(Utils::OpenHandle(*source));
+  i::ParseInfo info(&zone, script);
 
-  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));
-    }
+  auto module = TranslateAsmModule(&info, &thrower);
+  if (module == nullptr) {
+    return;
+  }
 
-    i::MaybeHandle<i::JSObject> object =
-        result.val->Instantiate(isolate, ffi, memory);
+  InstantiateModuleCommon(args, module->Begin(), module->End(), &thrower, true);
+}
 
-    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;
+
+  InstantiateModuleCommon(args, buffer.start, buffer.end, &thrower, false);
 }
 }  // namespace