Revert of [runtime] Introduce dedicated JSBoundFunction to represent bound functions.

src/runtime/runtime-function.cc

Index: src/runtime/runtime-function.cc
diff --git a/src/runtime/runtime-function.cc b/src/runtime/runtime-function.cc
index 24ed128f670a039c635e4b39a7277d5e50a33ca5..9ec4cda81a11f4f2cfab49c28d7a8804599d75ea 100644
--- a/src/runtime/runtime-function.cc
+++ b/src/runtime/runtime-function.cc
@@ -53,23 +53,23 @@
 
 RUNTIME_FUNCTION(Runtime_FunctionGetScript) {
   HandleScope scope(isolate);
-  DCHECK_EQ(1, args.length());
-  CONVERT_ARG_HANDLE_CHECKED(JSReceiver, function, 0);
-
-  if (function->IsJSBoundFunction()) return isolate->heap()->undefined_value();
-  Handle<Object> script(Handle<JSFunction>::cast(function)->shared()->script(),
-                        isolate);
+  DCHECK(args.length() == 1);
+
+  CONVERT_ARG_CHECKED(JSFunction, fun, 0);
+  Handle<Object> script = Handle<Object>(fun->shared()->script(), isolate);
   if (!script->IsScript()) return isolate->heap()->undefined_value();
+
   return *Script::GetWrapper(Handle<Script>::cast(script));
 }
 
 
 RUNTIME_FUNCTION(Runtime_FunctionGetSourceCode) {
   HandleScope scope(isolate);
-  DCHECK_EQ(1, args.length());
-  CONVERT_ARG_HANDLE_CHECKED(JSReceiver, function, 0);
-  if (function->IsJSBoundFunction()) return isolate->heap()->undefined_value();
-  return *Handle<JSFunction>::cast(function)->shared()->GetSourceCode();
+  DCHECK(args.length() == 1);
+
+  CONVERT_ARG_HANDLE_CHECKED(JSFunction, f, 0);
+  Handle<SharedFunctionInfo> shared(f->shared());
+  return *shared->GetSourceCode();
 }
 
 
@@ -152,6 +152,7 @@
 
   Handle<SharedFunctionInfo> target_shared(target->shared());
   Handle<SharedFunctionInfo> source_shared(source->shared());
+  RUNTIME_ASSERT(!source_shared->bound());
 
   if (!Compiler::Compile(source, KEEP_EXCEPTION)) {
     return isolate->heap()->exception();
@@ -308,6 +309,137 @@
 }
 
 
+RUNTIME_FUNCTION(Runtime_FunctionBindArguments) {
+  HandleScope scope(isolate);
+  DCHECK(args.length() == 5);
+  CONVERT_ARG_HANDLE_CHECKED(JSFunction, bound_function, 0);
+  CONVERT_ARG_HANDLE_CHECKED(JSReceiver, bindee, 1);
+  CONVERT_ARG_HANDLE_CHECKED(Object, this_object, 2);
+  CONVERT_NUMBER_ARG_HANDLE_CHECKED(new_length, 3);
+  CONVERT_ARG_HANDLE_CHECKED(Object, proto, 4);
+
+  // TODO(lrn): Create bound function in C++ code from premade shared info.
+  bound_function->shared()->set_bound(true);
+  bound_function->shared()->set_optimized_code_map(
+      isolate->heap()->cleared_optimized_code_map());
+  bound_function->shared()->set_inferred_name(isolate->heap()->empty_string());
+  bound_function->shared()->set_construct_stub(
+      *isolate->builtins()->JSBuiltinsConstructStub());
+  // Get all arguments of calling function (Function.prototype.bind).
+  int argc = 0;
+  base::SmartArrayPointer<Handle<Object>> arguments =
+      Runtime::GetCallerArguments(isolate, 0, &argc);
+  // Don't count the this-arg.
+  if (argc > 0) {
+    RUNTIME_ASSERT(arguments[0].is_identical_to(this_object));
+    argc--;
+  } else {
+    RUNTIME_ASSERT(this_object->IsUndefined());
+  }
+  // Initialize array of bindings (function, this, and any existing arguments
+  // if the function was already bound).
+  Handle<BindingsArray> new_bindings;
+  int out_index = 0;
+  Handle<TypeFeedbackVector> vector(
+      bound_function->shared()->feedback_vector());
+  if (bindee->IsJSFunction() && JSFunction::cast(*bindee)->shared()->bound()) {
+    Handle<BindingsArray> old_bindings(
+        JSFunction::cast(*bindee)->function_bindings());
+    RUNTIME_ASSERT(old_bindings->bindings_count() >= 0);
+    bindee = handle(old_bindings->bound_function(), isolate);
+    Handle<Object> old_bound_this(old_bindings->bound_this(), isolate);
+    new_bindings = BindingsArray::New(isolate, vector, bindee, old_bound_this,
+                                      old_bindings->bindings_count() + argc);
+    for (int n = old_bindings->bindings_count(); out_index < n; out_index++) {
+      new_bindings->set_binding(out_index, old_bindings->binding(out_index));
+    }
+  } else {
+    new_bindings =
+        BindingsArray::New(isolate, vector, bindee, this_object, argc);
+  }
+  // Copy arguments, skipping the first which is "this_arg".
+  for (int j = 0; j < argc; j++, out_index++) {
+    new_bindings->set_binding(out_index, *arguments[j + 1]);
+  }
+  new_bindings->set_map_no_write_barrier(isolate->heap()->fixed_array_map());
+  bound_function->set_function_bindings(*new_bindings);
+
+  // Update length. Have to remove the prototype first so that map migration
+  // is happy about the number of fields.
+  RUNTIME_ASSERT(bound_function->RemovePrototype());
+
+  // The new function should have the given prototype.
+  Handle<Map> bound_function_map =
+      bindee->IsConstructor()
+          ? isolate->bound_function_with_constructor_map()
+          : isolate->bound_function_without_constructor_map();
+  if (bound_function_map->prototype() != *proto) {
+    bound_function_map = Map::TransitionToPrototype(bound_function_map, proto,
+                                                    REGULAR_PROTOTYPE);
+  }
+  JSObject::MigrateToMap(bound_function, bound_function_map);
+  DCHECK_EQ(bindee->IsConstructor(), bound_function->IsConstructor());
+
+  Handle<String> length_string = isolate->factory()->length_string();
+  // These attributes must be kept in sync with how the bootstrapper
+  // configures the bound_function_map retrieved above.
+  // We use ...IgnoreAttributes() here because of length's read-onliness.
+  PropertyAttributes attr =
+      static_cast<PropertyAttributes>(DONT_ENUM | READ_ONLY);
+  RETURN_FAILURE_ON_EXCEPTION(
+      isolate, JSObject::SetOwnPropertyIgnoreAttributes(
+                   bound_function, length_string, new_length, attr));
+  return *bound_function;
+}
+
+
+RUNTIME_FUNCTION(Runtime_BoundFunctionGetBindings) {
+  HandleScope handles(isolate);
+  DCHECK(args.length() == 1);
+  CONVERT_ARG_HANDLE_CHECKED(JSReceiver, callable, 0);
+  if (callable->IsJSFunction()) {
+    Handle<JSFunction> function = Handle<JSFunction>::cast(callable);
+    if (function->shared()->bound()) {
+      RUNTIME_ASSERT(function->function_bindings()->IsBindingsArray());
+      Handle<BindingsArray> bindings(function->function_bindings());
+      return *BindingsArray::CreateRuntimeBindings(bindings);
+    }
+  }
+  return isolate->heap()->undefined_value();
+}
+
+
+RUNTIME_FUNCTION(Runtime_NewObjectFromBound) {
+  HandleScope scope(isolate);
+  DCHECK(args.length() == 1);
+  // First argument is a function to use as a constructor.
+  CONVERT_ARG_HANDLE_CHECKED(JSFunction, function, 0);
+  RUNTIME_ASSERT(function->shared()->bound());
+
+  // The argument is a bound function. Extract its bound arguments
+  // and callable.
+  Handle<BindingsArray> bound_args =
+      handle(BindingsArray::cast(function->function_bindings()));
+  int bound_argc = bound_args->bindings_count();
+  Handle<Object> bound_function(bound_args->bound_function(), isolate);
+  DCHECK(!bound_function->IsJSFunction() ||
+         !Handle<JSFunction>::cast(bound_function)->shared()->bound());
+
+  int total_argc = 0;
+  base::SmartArrayPointer<Handle<Object>> param_data =
+      Runtime::GetCallerArguments(isolate, bound_argc, &total_argc);
+  for (int i = 0; i < bound_argc; i++) {
+    param_data[i] = handle(bound_args->binding(i), isolate);
+  }
+
+  Handle<Object> result;
+  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
+      isolate, result, Execution::New(isolate, bound_function, bound_function,
+                                      total_argc, param_data.get()));
+  return *result;
+}
+
+
 RUNTIME_FUNCTION(Runtime_Call) {
   HandleScope scope(isolate);
   DCHECK_LE(2, args.length());
@@ -395,9 +527,9 @@
 
 RUNTIME_FUNCTION(Runtime_IsFunction) {
   SealHandleScope shs(isolate);
-  DCHECK_EQ(1, args.length());
-  CONVERT_ARG_CHECKED(Object, object, 0);
-  return isolate->heap()->ToBoolean(object->IsFunction());
+  DCHECK(args.length() == 1);
+  CONVERT_ARG_CHECKED(Object, obj, 0);
+  return isolate->heap()->ToBoolean(obj->IsJSFunction());
 }
 
 
@@ -412,11 +544,8 @@
 RUNTIME_FUNCTION(Runtime_FunctionToString) {
   HandleScope scope(isolate);
   DCHECK_EQ(1, args.length());
-  CONVERT_ARG_HANDLE_CHECKED(JSReceiver, function, 0);
-  return function->IsJSBoundFunction()
-             ? *JSBoundFunction::ToString(
-                   Handle<JSBoundFunction>::cast(function))
-             : *JSFunction::ToString(Handle<JSFunction>::cast(function));
+  CONVERT_ARG_HANDLE_CHECKED(JSFunction, function, 0);
+  return *JSFunction::ToString(function);
 }
 
 }  // namespace internal