[builtins] Migrate String.prototype.trim/trimLeft/trimRight to C++.

These builtins do call into C++ anyways, so there's no point in keeping
the JavaScript wrappers for them.

R=franzih@chromium.org
BUG=v8:5049

Review-Url: https://codereview.chromium.org/2018963002
Cr-Commit-Position: refs/heads/master@{#36553}

src/bootstrapper.cc

@@ -1340,6 +1340,12 @@ void Genesis::InitializeGlobal(Handle<JSGlobalObject> global_object,
                           1, true);
     SimpleInstallFunction(prototype, "charCodeAt",
                           Builtins::kStringPrototypeCharCodeAt, 1, true);
+    SimpleInstallFunction(prototype, "trim", Builtins::kStringPrototypeTrim, 0,
+                          false);
+    SimpleInstallFunction(prototype, "trimLeft",
+                          Builtins::kStringPrototypeTrimLeft, 0, false);
+    SimpleInstallFunction(prototype, "trimRight",
+                          Builtins::kStringPrototypeTrimRight, 0, false);
   }
 
   {

src/builtins.cc

@@ -179,6 +179,19 @@ BUILTIN_LIST_C(DEF_ARG_TYPE)
   }                                                                         \
   Handle<Type> name = Handle<Type>::cast(args.receiver())
 
+// Throws a TypeError for {method} if the receiver is not coercible to Object,
+// or converts the receiver to a String otherwise and assigns it to a new var
+// with the given {name}.
+#define TO_THIS_STRING(name, method)                                          \
+  if (args.receiver()->IsNull() || args.receiver()->IsUndefined()) {          \
+    THROW_NEW_ERROR_RETURN_FAILURE(                                           \
+        isolate,                                                              \
+        NewTypeError(MessageTemplate::kCalledOnNullOrUndefined,               \
+                     isolate->factory()->NewStringFromAsciiChecked(method))); \
+  }                                                                           \
+  Handle<String> name;                                                        \
+  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(                                         \
+      isolate, name, Object::ToString(isolate, args.receiver()))
 
 inline bool ClampedToInteger(Object* object, int* out) {
   // This is an extended version of ECMA-262 7.1.11 handling signed values
@@ -4541,6 +4554,27 @@ void Builtins::Generate_StringPrototypeCharCodeAt(
   assembler->Return(result);
 }
 
+// ES6 section 21.1.3.25 String.prototype.trim ()
+BUILTIN(StringPrototypeTrim) {
+  HandleScope scope(isolate);
+  TO_THIS_STRING(string, "String.prototype.trim");
+  return *String::Trim(string, String::kTrim);
+}
+
+// Non-standard WebKit extension
+BUILTIN(StringPrototypeTrimLeft) {
+  HandleScope scope(isolate);
+  TO_THIS_STRING(string, "String.prototype.trimLeft");
+  return *String::Trim(string, String::kTrimLeft);
+}
+
+// Non-standard WebKit extension
+BUILTIN(StringPrototypeTrimRight) {
+  HandleScope scope(isolate);
+  TO_THIS_STRING(string, "String.prototype.trimRight");
+  return *String::Trim(string, String::kTrimRight);
+}
+
 // -----------------------------------------------------------------------------
 // ES6 section 21.1 ArrayBuffer Objects
 

src/builtins.h

@@ -172,6 +172,9 @@ inline bool operator&(BuiltinExtraArguments lhs, BuiltinExtraArguments rhs) {
   V(ReflectSetPrototypeOf, kNone)                              \
                                                                \
   V(StringFromCharCode, kNone)                                 \
+  V(StringPrototypeTrim, kNone)                                \
+  V(StringPrototypeTrimLeft, kNone)                            \
+  V(StringPrototypeTrimRight, kNone)                           \
                                                                \
   V(SymbolConstructor, kNone)                                  \
   V(SymbolConstructor_ConstructStub, kTarget)                  \

src/js/string.js

@@ -518,25 +518,6 @@ function StringToLocaleUpperCase() {
   return %StringToUpperCase(TO_STRING(this));
 }
 
-// ES5, 15.5.4.20
-function StringTrimJS() {
-  CHECK_OBJECT_COERCIBLE(this, "String.prototype.trim");
-
-  return %StringTrim(TO_STRING(this), true, true);
-}
-
-function StringTrimLeft() {
-  CHECK_OBJECT_COERCIBLE(this, "String.prototype.trimLeft");
-
-  return %StringTrim(TO_STRING(this), true, false);
-}
-
-function StringTrimRight() {
-  CHECK_OBJECT_COERCIBLE(this, "String.prototype.trimRight");
-
-  return %StringTrim(TO_STRING(this), false, true);
-}
-
 
 // ES6 draft, revision 26 (2014-07-18), section B.2.3.2.1
 function HtmlEscape(str) {
@@ -850,9 +831,6 @@ utils.InstallFunctions(GlobalString.prototype, DONT_ENUM, [
   "toLocaleLowerCase", StringToLocaleLowerCase,
   "toUpperCase", StringToUpperCaseJS,
   "toLocaleUpperCase", StringToLocaleUpperCase,
-  "trim", StringTrimJS,
-  "trimLeft", StringTrimLeft,
-  "trimRight", StringTrimRight,
 
   "link", StringLink,
   "anchor", StringAnchor,

src/objects.cc

@@ -9981,6 +9981,34 @@ bool DescriptorArray::IsEqualTo(DescriptorArray* other) {
 }
 #endif
 
+// static
+Handle<String> String::Trim(Handle<String> string, TrimMode mode) {
+  Isolate* const isolate = string->GetIsolate();
+  string = String::Flatten(string);
+  int const length = string->length();
+
+  // Perform left trimming if requested.
+  int left = 0;
+  UnicodeCache* unicode_cache = isolate->unicode_cache();
+  if (mode == kTrim || mode == kTrimLeft) {
+    while (left < length &&
+           unicode_cache->IsWhiteSpaceOrLineTerminator(string->Get(left))) {
+      left++;
+    }
+  }
+
+  // Perform right trimming if requested.
+  int right = length;
+  if (mode == kTrim || mode == kTrimRight) {
+    while (
+        right > left &&
+        unicode_cache->IsWhiteSpaceOrLineTerminator(string->Get(right - 1))) {
+      right--;
+    }
+  }
+
+  return isolate->factory()->NewSubString(string, left, right);
+}
 
 bool String::LooksValid() {
   if (!GetIsolate()->heap()->Contains(this)) return false;

src/objects.h

@@ -8861,6 +8861,10 @@ class String: public Name {
   // Conversion.
   inline bool AsArrayIndex(uint32_t* index);
 
+  // Trimming.
+  enum TrimMode { kTrim, kTrimLeft, kTrimRight };
+  static Handle<String> Trim(Handle<String> string, TrimMode mode);
+
   DECLARE_CAST(String)
 
   void PrintOn(FILE* out);

src/runtime/runtime-strings.cc

@@ -1088,39 +1088,6 @@ RUNTIME_FUNCTION(Runtime_StringToUpperCase) {
   return ConvertCase(s, isolate, isolate->runtime_state()->to_upper_mapping());
 }
 
-
-RUNTIME_FUNCTION(Runtime_StringTrim) {
-  HandleScope scope(isolate);
-  DCHECK(args.length() == 3);
-
-  CONVERT_ARG_HANDLE_CHECKED(String, string, 0);
-  CONVERT_BOOLEAN_ARG_CHECKED(trimLeft, 1);
-  CONVERT_BOOLEAN_ARG_CHECKED(trimRight, 2);
-
-  string = String::Flatten(string);
-  int length = string->length();
-
-  int left = 0;
-  UnicodeCache* unicode_cache = isolate->unicode_cache();
-  if (trimLeft) {
-    while (left < length &&
-           unicode_cache->IsWhiteSpaceOrLineTerminator(string->Get(left))) {
-      left++;
-    }
-  }
-
-  int right = length;
-  if (trimRight) {
-    while (
-        right > left &&
-        unicode_cache->IsWhiteSpaceOrLineTerminator(string->Get(right - 1))) {
-      right--;
-    }
-  }
-
-  return *isolate->factory()->NewSubString(string, left, right);
-}
-
 RUNTIME_FUNCTION(Runtime_StringLessThan) {
   HandleScope handle_scope(isolate);
   DCHECK_EQ(2, args.length());

src/runtime/runtime.h

@@ -831,7 +831,6 @@ namespace internal {
   F(StringToArray, 2, 1)                  \
   F(StringToLowerCase, 1, 1)              \
   F(StringToUpperCase, 1, 1)              \
-  F(StringTrim, 3, 1)                     \
   F(StringLessThan, 2, 1)                 \
   F(StringLessThanOrEqual, 2, 1)          \
   F(StringGreaterThan, 2, 1)              \