[builtins] Move StringEndsWith to a C++ builtin.

BUG=v8:5364

Review-Url: https://codereview.chromium.org/2406873002
Cr-Commit-Position: refs/heads/master@{#40164}

src/bootstrapper.cc

@@ -1437,6 +1437,8 @@ void Genesis::InitializeGlobal(Handle<JSGlobalObject> global_object,
                           1, true);
     SimpleInstallFunction(prototype, "charCodeAt",
                           Builtins::kStringPrototypeCharCodeAt, 1, true);
+    SimpleInstallFunction(prototype, "endsWith",
+                          Builtins::kStringPrototypeEndsWith, 1, false);
     SimpleInstallFunction(prototype, "includes",
                           Builtins::kStringPrototypeIncludes, 1, false);
     SimpleInstallFunction(prototype, "indexOf",

src/builtins/builtins-string.cc

@@ -781,6 +781,56 @@ void Builtins::Generate_StringPrototypeCharCodeAt(
   assembler->Return(result);
 }
 
+// ES6 section 21.1.3.6
+// String.prototype.endsWith ( searchString [ , endPosition ] )
+BUILTIN(StringPrototypeEndsWith) {
+  HandleScope handle_scope(isolate);
+  TO_THIS_STRING(str, "String.prototype.endsWith");
+
+  // Check if the search string is a regExp and fail if it is.
+  Handle<Object> search = args.atOrUndefined(isolate, 1);
+  Maybe<bool> is_reg_exp = Object::IsRegExp(isolate, search);
+  if (is_reg_exp.IsNothing()) {
+    DCHECK(isolate->has_pending_exception());
+    return isolate->heap()->exception();
+  }
+  if (is_reg_exp.FromJust()) {
+    THROW_NEW_ERROR_RETURN_FAILURE(
+        isolate, NewTypeError(MessageTemplate::kFirstArgumentNotRegExp,
+                              isolate->factory()->NewStringFromStaticChars(
+                                  "String.prototype.endsWith")));
+  }
+  Handle<String> search_string;
+  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, search_string,
+                                     Object::ToString(isolate, search));
+
+  Handle<Object> position = args.atOrUndefined(isolate, 2);
+  int end;
+
+  if (position->IsUndefined(isolate)) {
+    end = str->length();
+  } else {
+    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, position,
+                                       Object::ToInteger(isolate, position));
+    double index = std::max(position->Number(), 0.0);
+    index = std::min(index, static_cast<double>(str->length()));
+    end = static_cast<uint32_t>(index);
+  }
+
+  int start = end - search_string->length();
+  if (start < 0) return *isolate->factory()->false_value();
+
+  FlatStringReader str_reader(isolate, String::Flatten(str));
+  FlatStringReader search_reader(isolate, String::Flatten(search_string));
+
+  for (int i = 0; i < search_string->length(); i++) {
+    if (str_reader.Get(start + i) != search_reader.Get(i)) {
+      return *isolate->factory()->false_value();
+    }
+  }
+  return *isolate->factory()->true_value();
+}
+
 // ES6 section 21.1.3.7
 // String.prototype.includes ( searchString [ , position ] )
 BUILTIN(StringPrototypeIncludes) {

src/builtins/builtins.h

@@ -612,6 +612,9 @@ namespace internal {
   TFJ(StringPrototypeCharAt, 2)                                               \
   /* ES6 section 21.1.3.2 String.prototype.charCodeAt ( pos ) */              \
   TFJ(StringPrototypeCharCodeAt, 2)                                           \
+  /* ES6 section 21.1.3.6 */                                                  \
+  /* String.prototype.endsWith ( searchString [ , endPosition ] ) */          \
+  CPP(StringPrototypeEndsWith)                                                \
   /* ES6 section 21.1.3.7 */                                                  \
   /* String.prototype.includes ( searchString [ , position ] ) */             \
   CPP(StringPrototypeIncludes)                                                \

src/js/string.js

@@ -406,33 +406,6 @@ function StringStartsWith(searchString, position) {  // length == 1
 %FunctionSetLength(StringStartsWith, 1);
 
 
-// ES6 draft 04-05-14, section 21.1.3.7
-function StringEndsWith(searchString, position) {  // length == 1
-  CHECK_OBJECT_COERCIBLE(this, "String.prototype.endsWith");
-
-  var s = TO_STRING(this);
-
-  if (IsRegExp(searchString)) {
-    throw %make_type_error(kFirstArgumentNotRegExp, "String.prototype.endsWith");
-  }
-
-  var ss = TO_STRING(searchString);
-  var s_len = s.length;
-  var pos = !IS_UNDEFINED(position) ? TO_INTEGER(position) : s_len
-
-  var end = MinSimple(MaxSimple(pos, 0), s_len);
-  var ss_len = ss.length;
-  var start = end - ss_len;
-  if (start < 0) {
-    return false;
-  }
-
-  return %_SubString(s, start, start + ss_len) === ss;
-}
-
-%FunctionSetLength(StringEndsWith, 1);
-
-
 // ES6 Draft 05-22-2014, section 21.1.3.3
 function StringCodePointAt(pos) {
   CHECK_OBJECT_COERCIBLE(this, "String.prototype.codePointAt");
@@ -490,7 +463,6 @@ utils.InstallFunctions(GlobalString, DONT_ENUM, [
 utils.InstallFunctions(GlobalString.prototype, DONT_ENUM, [
   "codePointAt", StringCodePointAt,
   "concat", StringConcat,
-  "endsWith", StringEndsWith,
   "match", StringMatchJS,
   "repeat", StringRepeat,
   "replace", StringReplace,

test/mjsunit/es6/string-endswith.js

@@ -34,6 +34,7 @@ assertFalse(testString.endsWith("world"));
 assertFalse(testString.endsWith("Hello World!"));
 assertFalse(testString.endsWith(null));
 assertFalse(testString.endsWith(undefined));
+assertFalse(testString.endsWith());
 
 assertTrue("null".endsWith(null));
 assertTrue("undefined".endsWith(undefined));