Split yet more runtime functions into separate files.

src/runtime/runtime-function.cc

+// Copyright 2014 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/v8.h"
+
+#include "src/accessors.h"
+#include "src/arguments.h"
+#include "src/compiler.h"
+#include "src/deoptimizer.h"
+#include "src/frames.h"
+#include "src/runtime/runtime.h"
+#include "src/runtime/runtime-utils.h"
+
+namespace v8 {
+namespace internal {
+
+RUNTIME_FUNCTION(Runtime_IsSloppyModeFunction) {
+  SealHandleScope shs(isolate);
+  DCHECK(args.length() == 1);
+  CONVERT_ARG_CHECKED(JSReceiver, callable, 0);
+  if (!callable->IsJSFunction()) {
+    HandleScope scope(isolate);
+    Handle<Object> delegate;
+    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
+        isolate, delegate, Execution::TryGetFunctionDelegate(
+                               isolate, Handle<JSReceiver>(callable)));
+    callable = JSFunction::cast(*delegate);
+  }
+  JSFunction* function = JSFunction::cast(callable);
+  SharedFunctionInfo* shared = function->shared();
+  return isolate->heap()->ToBoolean(shared->strict_mode() == SLOPPY);
+}
+
+
+RUNTIME_FUNCTION(Runtime_GetDefaultReceiver) {
+  SealHandleScope shs(isolate);
+  DCHECK(args.length() == 1);
+  CONVERT_ARG_CHECKED(JSReceiver, callable, 0);
+
+  if (!callable->IsJSFunction()) {
+    HandleScope scope(isolate);
+    Handle<Object> delegate;
+    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
+        isolate, delegate, Execution::TryGetFunctionDelegate(
+                               isolate, Handle<JSReceiver>(callable)));
+    callable = JSFunction::cast(*delegate);
+  }
+  JSFunction* function = JSFunction::cast(callable);
+
+  SharedFunctionInfo* shared = function->shared();
+  if (shared->native() || shared->strict_mode() == STRICT) {
+    return isolate->heap()->undefined_value();
+  }
+  // Returns undefined for strict or native functions, or
+  // the associated global receiver for "normal" functions.
+
+  return function->global_proxy();
+}
+
+
+RUNTIME_FUNCTION(Runtime_FunctionGetName) {
+  SealHandleScope shs(isolate);
+  DCHECK(args.length() == 1);
+
+  CONVERT_ARG_CHECKED(JSFunction, f, 0);
+  return f->shared()->name();
+}
+
+
+RUNTIME_FUNCTION(Runtime_FunctionSetName) {
+  SealHandleScope shs(isolate);
+  DCHECK(args.length() == 2);
+
+  CONVERT_ARG_CHECKED(JSFunction, f, 0);
+  CONVERT_ARG_CHECKED(String, name, 1);
+  f->shared()->set_name(name);
+  return isolate->heap()->undefined_value();
+}
+
+
+RUNTIME_FUNCTION(Runtime_FunctionNameShouldPrintAsAnonymous) {
+  SealHandleScope shs(isolate);
+  DCHECK(args.length() == 1);
+  CONVERT_ARG_CHECKED(JSFunction, f, 0);
+  return isolate->heap()->ToBoolean(
+      f->shared()->name_should_print_as_anonymous());
+}
+
+
+RUNTIME_FUNCTION(Runtime_FunctionMarkNameShouldPrintAsAnonymous) {
+  SealHandleScope shs(isolate);
+  DCHECK(args.length() == 1);
+  CONVERT_ARG_CHECKED(JSFunction, f, 0);
+  f->shared()->set_name_should_print_as_anonymous(true);
+  return isolate->heap()->undefined_value();
+}
+
+
+RUNTIME_FUNCTION(Runtime_FunctionIsArrow) {
+  SealHandleScope shs(isolate);
+  DCHECK(args.length() == 1);
+  CONVERT_ARG_CHECKED(JSFunction, f, 0);
+  return isolate->heap()->ToBoolean(f->shared()->is_arrow());
+}
+
+
+RUNTIME_FUNCTION(Runtime_FunctionIsConciseMethod) {
+  SealHandleScope shs(isolate);
+  DCHECK(args.length() == 1);
+  CONVERT_ARG_CHECKED(JSFunction, f, 0);
+  return isolate->heap()->ToBoolean(f->shared()->is_concise_method());
+}
+
+
+RUNTIME_FUNCTION(Runtime_FunctionRemovePrototype) {
+  SealHandleScope shs(isolate);
+  DCHECK(args.length() == 1);
+
+  CONVERT_ARG_CHECKED(JSFunction, f, 0);
+  RUNTIME_ASSERT(f->RemovePrototype());
+
+  return isolate->heap()->undefined_value();
+}
+
+
+RUNTIME_FUNCTION(Runtime_FunctionGetScript) {
+  HandleScope scope(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(args.length() == 1);
+
+  CONVERT_ARG_HANDLE_CHECKED(JSFunction, f, 0);
+  Handle<SharedFunctionInfo> shared(f->shared());
+  return *shared->GetSourceCode();
+}
+
+
+RUNTIME_FUNCTION(Runtime_FunctionGetScriptSourcePosition) {
+  SealHandleScope shs(isolate);
+  DCHECK(args.length() == 1);
+
+  CONVERT_ARG_CHECKED(JSFunction, fun, 0);
+  int pos = fun->shared()->start_position();
+  return Smi::FromInt(pos);
+}
+
+
+RUNTIME_FUNCTION(Runtime_FunctionGetPositionForOffset) {
+  SealHandleScope shs(isolate);
+  DCHECK(args.length() == 2);
+
+  CONVERT_ARG_CHECKED(Code, code, 0);
+  CONVERT_NUMBER_CHECKED(int, offset, Int32, args[1]);
+
+  RUNTIME_ASSERT(0 <= offset && offset < code->Size());
+
+  Address pc = code->address() + offset;
+  return Smi::FromInt(code->SourcePosition(pc));
+}
+
+
+RUNTIME_FUNCTION(Runtime_FunctionSetInstanceClassName) {
+  SealHandleScope shs(isolate);
+  DCHECK(args.length() == 2);
+
+  CONVERT_ARG_CHECKED(JSFunction, fun, 0);
+  CONVERT_ARG_CHECKED(String, name, 1);
+  fun->SetInstanceClassName(name);
+  return isolate->heap()->undefined_value();
+}
+
+
+RUNTIME_FUNCTION(Runtime_FunctionSetLength) {
+  SealHandleScope shs(isolate);
+  DCHECK(args.length() == 2);
+
+  CONVERT_ARG_CHECKED(JSFunction, fun, 0);
+  CONVERT_SMI_ARG_CHECKED(length, 1);
+  RUNTIME_ASSERT((length & 0xC0000000) == 0xC0000000 ||
+                 (length & 0xC0000000) == 0x0);
+  fun->shared()->set_length(length);
+  return isolate->heap()->undefined_value();
+}
+
+
+RUNTIME_FUNCTION(Runtime_FunctionSetPrototype) {
+  HandleScope scope(isolate);
+  DCHECK(args.length() == 2);
+
+  CONVERT_ARG_HANDLE_CHECKED(JSFunction, fun, 0);
+  CONVERT_ARG_HANDLE_CHECKED(Object, value, 1);
+  RUNTIME_ASSERT(fun->should_have_prototype());
+  Accessors::FunctionSetPrototype(fun, value);
+  return args[0];  // return TOS
+}
+
+
+RUNTIME_FUNCTION(Runtime_FunctionIsAPIFunction) {
+  SealHandleScope shs(isolate);
+  DCHECK(args.length() == 1);
+
+  CONVERT_ARG_CHECKED(JSFunction, f, 0);
+  return isolate->heap()->ToBoolean(f->shared()->IsApiFunction());
+}
+
+
+RUNTIME_FUNCTION(Runtime_FunctionIsBuiltin) {
+  SealHandleScope shs(isolate);
+  DCHECK(args.length() == 1);
+
+  CONVERT_ARG_CHECKED(JSFunction, f, 0);
+  return isolate->heap()->ToBoolean(f->IsBuiltin());
+}
+
+
+RUNTIME_FUNCTION(Runtime_SetCode) {
+  HandleScope scope(isolate);
+  DCHECK(args.length() == 2);
+
+  CONVERT_ARG_HANDLE_CHECKED(JSFunction, target, 0);
+  CONVERT_ARG_HANDLE_CHECKED(JSFunction, source, 1);
+
+  Handle<SharedFunctionInfo> target_shared(target->shared());
+  Handle<SharedFunctionInfo> source_shared(source->shared());
+  RUNTIME_ASSERT(!source_shared->bound());
+
+  if (!Compiler::EnsureCompiled(source, KEEP_EXCEPTION)) {
+    return isolate->heap()->exception();
+  }
+
+  // Mark both, the source and the target, as un-flushable because the
+  // shared unoptimized code makes them impossible to enqueue in a list.
+  DCHECK(target_shared->code()->gc_metadata() == NULL);
+  DCHECK(source_shared->code()->gc_metadata() == NULL);
+  target_shared->set_dont_flush(true);
+  source_shared->set_dont_flush(true);
+
+  // Set the code, scope info, formal parameter count, and the length
+  // of the target shared function info.
+  target_shared->ReplaceCode(source_shared->code());
+  target_shared->set_scope_info(source_shared->scope_info());
+  target_shared->set_length(source_shared->length());
+  target_shared->set_feedback_vector(source_shared->feedback_vector());
+  target_shared->set_formal_parameter_count(
+      source_shared->formal_parameter_count());
+  target_shared->set_script(source_shared->script());
+  target_shared->set_start_position_and_type(
+      source_shared->start_position_and_type());
+  target_shared->set_end_position(source_shared->end_position());
+  bool was_native = target_shared->native();
+  target_shared->set_compiler_hints(source_shared->compiler_hints());
+  target_shared->set_native(was_native);
+  target_shared->set_profiler_ticks(source_shared->profiler_ticks());
+
+  // Set the code of the target function.
+  target->ReplaceCode(source_shared->code());
+  DCHECK(target->next_function_link()->IsUndefined());
+
+  // Make sure we get a fresh copy of the literal vector to avoid cross
+  // context contamination.
+  Handle<Context> context(source->context());
+  int number_of_literals = source->NumberOfLiterals();
+  Handle<FixedArray> literals =
+      isolate->factory()->NewFixedArray(number_of_literals, TENURED);
+  if (number_of_literals > 0) {
+    literals->set(JSFunction::kLiteralNativeContextIndex,
+                  context->native_context());
+  }
+  target->set_context(*context);
+  target->set_literals(*literals);
+
+  if (isolate->logger()->is_logging_code_events() ||
+      isolate->cpu_profiler()->is_profiling()) {
+    isolate->logger()->LogExistingFunction(source_shared,
+                                           Handle<Code>(source_shared->code()));
+  }
+
+  return *target;
+}
+
+
+// Set the native flag on the function.
+// This is used to decide if we should transform null and undefined
+// into the global object when doing call and apply.
+RUNTIME_FUNCTION(Runtime_SetNativeFlag) {
+  SealHandleScope shs(isolate);
+  RUNTIME_ASSERT(args.length() == 1);
+
+  CONVERT_ARG_CHECKED(Object, object, 0);
+
+  if (object->IsJSFunction()) {
+    JSFunction* func = JSFunction::cast(object);
+    func->shared()->set_native(true);
+  }
+  return isolate->heap()->undefined_value();
+}
+
+
+RUNTIME_FUNCTION(Runtime_SetInlineBuiltinFlag) {
+  SealHandleScope shs(isolate);
+  RUNTIME_ASSERT(args.length() == 1);
+  CONVERT_ARG_HANDLE_CHECKED(Object, object, 0);
+
+  if (object->IsJSFunction()) {
+    JSFunction* func = JSFunction::cast(*object);
+    func->shared()->set_inline_builtin(true);
+  }
+  return isolate->heap()->undefined_value();
+}
+
+
+// Find the arguments of the JavaScript function invocation that called
+// into C++ code. Collect these in a newly allocated array of handles (possibly
+// prefixed by a number of empty handles).
+static SmartArrayPointer<Handle<Object> > GetCallerArguments(Isolate* isolate,
+                                                             int prefix_argc,
+                                                             int* total_argc) {
+  // Find frame containing arguments passed to the caller.
+  JavaScriptFrameIterator it(isolate);
+  JavaScriptFrame* frame = it.frame();
+  List<JSFunction*> functions(2);
+  frame->GetFunctions(&functions);
+  if (functions.length() > 1) {
+    int inlined_jsframe_index = functions.length() - 1;
+    JSFunction* inlined_function = functions[inlined_jsframe_index];
+    SlotRefValueBuilder slot_refs(
+        frame, inlined_jsframe_index,
+        inlined_function->shared()->formal_parameter_count());
+
+    int args_count = slot_refs.args_length();
+
+    *total_argc = prefix_argc + args_count;
+    SmartArrayPointer<Handle<Object> > param_data(
+        NewArray<Handle<Object> >(*total_argc));
+    slot_refs.Prepare(isolate);
+    for (int i = 0; i < args_count; i++) {
+      Handle<Object> val = slot_refs.GetNext(isolate, 0);
+      param_data[prefix_argc + i] = val;
+    }
+    slot_refs.Finish(isolate);
+
+    return param_data;
+  } else {
+    it.AdvanceToArgumentsFrame();
+    frame = it.frame();
+    int args_count = frame->ComputeParametersCount();
+
+    *total_argc = prefix_argc + args_count;
+    SmartArrayPointer<Handle<Object> > param_data(
+        NewArray<Handle<Object> >(*total_argc));
+    for (int i = 0; i < args_count; i++) {
+      Handle<Object> val = Handle<Object>(frame->GetParameter(i), isolate);
+      param_data[prefix_argc + i] = val;
+    }
+    return param_data;
+  }
+}
+
+
+RUNTIME_FUNCTION(Runtime_FunctionBindArguments) {
+  HandleScope scope(isolate);
+  DCHECK(args.length() == 4);
+  CONVERT_ARG_HANDLE_CHECKED(JSFunction, bound_function, 0);
+  CONVERT_ARG_HANDLE_CHECKED(Object, bindee, 1);
+  CONVERT_ARG_HANDLE_CHECKED(Object, this_object, 2);
+  CONVERT_NUMBER_ARG_HANDLE_CHECKED(new_length, 3);
+
+  // TODO(lrn): Create bound function in C++ code from premade shared info.
+  bound_function->shared()->set_bound(true);
+  // Get all arguments of calling function (Function.prototype.bind).
+  int argc = 0;
+  SmartArrayPointer<Handle<Object> > arguments =
+      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<FixedArray> new_bindings;
+  int i;
+  if (bindee->IsJSFunction() && JSFunction::cast(*bindee)->shared()->bound()) {
+    Handle<FixedArray> old_bindings(
+        JSFunction::cast(*bindee)->function_bindings());
+    RUNTIME_ASSERT(old_bindings->length() > JSFunction::kBoundFunctionIndex);
+    new_bindings =
+        isolate->factory()->NewFixedArray(old_bindings->length() + argc);
+    bindee = Handle<Object>(old_bindings->get(JSFunction::kBoundFunctionIndex),
+                            isolate);
+    i = 0;
+    for (int n = old_bindings->length(); i < n; i++) {
+      new_bindings->set(i, old_bindings->get(i));
+    }
+  } else {
+    int array_size = JSFunction::kBoundArgumentsStartIndex + argc;
+    new_bindings = isolate->factory()->NewFixedArray(array_size);
+    new_bindings->set(JSFunction::kBoundFunctionIndex, *bindee);
+    new_bindings->set(JSFunction::kBoundThisIndex, *this_object);
+    i = 2;
+  }
+  // Copy arguments, skipping the first which is "this_arg".
+  for (int j = 0; j < argc; j++, i++) {
+    new_bindings->set(i, *arguments[j + 1]);
+  }
+  new_bindings->set_map_no_write_barrier(
+      isolate->heap()->fixed_cow_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());
+  Handle<Map> bound_function_map(
+      isolate->native_context()->bound_function_map());
+  JSObject::MigrateToMap(bound_function, bound_function_map);
+  Handle<String> length_string = isolate->factory()->length_string();
+  PropertyAttributes attr =
+      static_cast<PropertyAttributes>(DONT_DELETE | 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()) {
+      Handle<FixedArray> bindings(function->function_bindings());
+      RUNTIME_ASSERT(bindings->map() == isolate->heap()->fixed_cow_array_map());
+      return *isolate->factory()->NewJSArrayWithElements(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<FixedArray> bound_args =
+      Handle<FixedArray>(FixedArray::cast(function->function_bindings()));
+  int bound_argc = bound_args->length() - JSFunction::kBoundArgumentsStartIndex;
+  Handle<Object> bound_function(
+      JSReceiver::cast(bound_args->get(JSFunction::kBoundFunctionIndex)),
+      isolate);
+  DCHECK(!bound_function->IsJSFunction() ||
+         !Handle<JSFunction>::cast(bound_function)->shared()->bound());
+
+  int total_argc = 0;
+  SmartArrayPointer<Handle<Object> > param_data =
+      GetCallerArguments(isolate, bound_argc, &total_argc);
+  for (int i = 0; i < bound_argc; i++) {
+    param_data[i] = Handle<Object>(
+        bound_args->get(JSFunction::kBoundArgumentsStartIndex + i), isolate);
+  }
+
+  if (!bound_function->IsJSFunction()) {
+    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
+        isolate, bound_function,
+        Execution::TryGetConstructorDelegate(isolate, bound_function));
+  }
+  DCHECK(bound_function->IsJSFunction());
+
+  Handle<Object> result;
+  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
+      isolate, result, Execution::New(Handle<JSFunction>::cast(bound_function),
+                                      total_argc, param_data.get()));
+  return *result;
+}
+
+
+RUNTIME_FUNCTION(Runtime_Call) {
+  HandleScope scope(isolate);
+  DCHECK(args.length() >= 2);
+  int argc = args.length() - 2;
+  CONVERT_ARG_CHECKED(JSReceiver, fun, argc + 1);
+  Object* receiver = args[0];
+
+  // If there are too many arguments, allocate argv via malloc.
+  const int argv_small_size = 10;
+  Handle<Object> argv_small_buffer[argv_small_size];
+  SmartArrayPointer<Handle<Object> > argv_large_buffer;
+  Handle<Object>* argv = argv_small_buffer;
+  if (argc > argv_small_size) {
+    argv = new Handle<Object>[argc];
+    if (argv == NULL) return isolate->StackOverflow();
+    argv_large_buffer = SmartArrayPointer<Handle<Object> >(argv);
+  }
+
+  for (int i = 0; i < argc; ++i) {
+    argv[i] = Handle<Object>(args[1 + i], isolate);
+  }
+
+  Handle<JSReceiver> hfun(fun);
+  Handle<Object> hreceiver(receiver, isolate);
+  Handle<Object> result;
+  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
+      isolate, result,
+      Execution::Call(isolate, hfun, hreceiver, argc, argv, true));
+  return *result;
+}
+
+
+RUNTIME_FUNCTION(Runtime_Apply) {
+  HandleScope scope(isolate);
+  DCHECK(args.length() == 5);
+  CONVERT_ARG_HANDLE_CHECKED(JSReceiver, fun, 0);
+  CONVERT_ARG_HANDLE_CHECKED(Object, receiver, 1);
+  CONVERT_ARG_HANDLE_CHECKED(JSObject, arguments, 2);
+  CONVERT_INT32_ARG_CHECKED(offset, 3);
+  CONVERT_INT32_ARG_CHECKED(argc, 4);
+  RUNTIME_ASSERT(offset >= 0);
+  // Loose upper bound to allow fuzzing. We'll most likely run out of
+  // stack space before hitting this limit.
+  static int kMaxArgc = 1000000;
+  RUNTIME_ASSERT(argc >= 0 && argc <= kMaxArgc);
+
+  // If there are too many arguments, allocate argv via malloc.
+  const int argv_small_size = 10;
+  Handle<Object> argv_small_buffer[argv_small_size];
+  SmartArrayPointer<Handle<Object> > argv_large_buffer;
+  Handle<Object>* argv = argv_small_buffer;
+  if (argc > argv_small_size) {
+    argv = new Handle<Object>[argc];
+    if (argv == NULL) return isolate->StackOverflow();
+    argv_large_buffer = SmartArrayPointer<Handle<Object> >(argv);
+  }
+
+  for (int i = 0; i < argc; ++i) {
+    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
+        isolate, argv[i], Object::GetElement(isolate, arguments, offset + i));
+  }
+
+  Handle<Object> result;
+  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
+      isolate, result,
+      Execution::Call(isolate, fun, receiver, argc, argv, true));
+  return *result;
+}
+
+
+RUNTIME_FUNCTION(Runtime_GetFunctionDelegate) {
+  HandleScope scope(isolate);
+  DCHECK(args.length() == 1);
+  CONVERT_ARG_HANDLE_CHECKED(Object, object, 0);
+  RUNTIME_ASSERT(!object->IsJSFunction());
+  return *Execution::GetFunctionDelegate(isolate, object);
+}
+
+
+RUNTIME_FUNCTION(Runtime_GetConstructorDelegate) {
+  HandleScope scope(isolate);
+  DCHECK(args.length() == 1);
+  CONVERT_ARG_HANDLE_CHECKED(Object, object, 0);
+  RUNTIME_ASSERT(!object->IsJSFunction());
+  return *Execution::GetConstructorDelegate(isolate, object);
+}
+
+
+RUNTIME_FUNCTION(RuntimeReference_CallFunction) {
+  SealHandleScope shs(isolate);
+  return __RT_impl_Runtime_Call(args, isolate);
+}
+
+
+RUNTIME_FUNCTION(RuntimeReference_IsConstructCall) {
+  SealHandleScope shs(isolate);
+  DCHECK(args.length() == 0);
+  JavaScriptFrameIterator it(isolate);
+  JavaScriptFrame* frame = it.frame();
+  return isolate->heap()->ToBoolean(frame->IsConstructor());
+}
+
+
+RUNTIME_FUNCTION(RuntimeReference_IsFunction) {
+  SealHandleScope shs(isolate);
+  DCHECK(args.length() == 1);
+  CONVERT_ARG_CHECKED(Object, obj, 0);
+  return isolate->heap()->ToBoolean(obj->IsJSFunction());
+}
+}
+}  // namespace v8::internal