[Interpreter] Add support for new.target

BUG=v8:4280
LOG=N

Review URL: https://codereview.chromium.org/1419273008

Cr-Commit-Position: refs/heads/master@{#31862}

src/interpreter/bytecode-generator.cc

@@ -2050,9 +2050,6 @@ void BytecodeGenerator::VisitThisFunctionVariable(Variable* variable) {
 void BytecodeGenerator::VisitNewTargetVariable(Variable* variable) {
   if (variable == nullptr) return;
 
-  // TODO(rmcilroy): Remove once we have tests which exercise this code path.
-  UNIMPLEMENTED();
-
   // Store the closure we were called with in the this_function_var.
   builder()->CallRuntime(Runtime::kGetOriginalConstructor, Register(), 0);
   VisitVariableAssignment(variable, FeedbackVectorSlot::Invalid());

test/cctest/interpreter/test-bytecode-generator.cc

@@ -5188,6 +5188,32 @@ TEST(ThisFunction) {
   }
 }
 
+
+TEST(NewTarget) {
+  InitializedHandleScope handle_scope;
+  BytecodeGeneratorHelper helper;
+
+  ExpectedSnippet<int> snippets[] = {
+      {"return new.target;",
+       1 * kPointerSize,
+       1,
+       10,
+       {
+           B(CallRuntime), U16(Runtime::kGetOriginalConstructor), R(0),  //
+                           U8(0),                                        //
+           B(Star), R(0),                                                //
+           B(Ldar), R(0),                                                //
+           B(Return),                                                    //
+       }},
+  };
+
+  for (size_t i = 0; i < arraysize(snippets); i++) {
+    Handle<BytecodeArray> bytecode_array =
+        helper.MakeBytecodeForFunctionBody(snippets[i].code_snippet);
+    CheckBytecodeArrayEqual(snippets[i], bytecode_array);
+  }
+}
+
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8

test/cctest/interpreter/test-interpreter.cc

@@ -2933,6 +2933,24 @@ TEST(InterpreterThisFunction) {
   CHECK(return_value->SameValue(*factory->NewStringFromStaticChars("f")));
 }
 
+
+TEST(InterpreterNewTarget) {
+  HandleAndZoneScope handles;
+  i::Isolate* isolate = handles.main_isolate();
+  i::Factory* factory = isolate->factory();
+
+  // TODO(rmcilroy): Add tests that we get the original constructor for
+  // superclass constructors once we have class support.
+  InterpreterTester tester(handles.main_isolate(),
+                           "function f() { this.a = new.target; }");
+  auto callable = tester.GetCallable<>();
+  callable().ToHandleChecked();
+
+  Handle<Object> new_target_name = v8::Utils::OpenHandle(
+      *CompileRun("(function() { return (new f()).a.name; })();"));
+  CHECK(new_target_name->SameValue(*factory->NewStringFromStaticChars("f")));
+}
+
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8