[runtime] Add fast-paths for common conversion methods

Add inlineable fast-paths for Object::ToPropertyKey, Object::ToLength and
Object::ToIndex for the most common argument types.

BUG=

Review-Url: https://codereview.chromium.org/2587013002
Cr-Commit-Position: refs/heads/master@{#41839}

src/objects-inl.h

@@ -1101,6 +1101,13 @@ MaybeHandle<Name> Object::ToName(Isolate* isolate, Handle<Object> input) {
   return ConvertToName(isolate, input);
 }
 
+// static
+MaybeHandle<Object> Object::ToPropertyKey(Isolate* isolate,
+                                          Handle<Object> value) {
+  if (value->IsSmi() || HeapObject::cast(*value)->IsName()) return value;
+  return ConvertToPropertyKey(isolate, value);
+}
+
 // static
 MaybeHandle<Object> Object::ToPrimitive(Handle<Object> input,
                                         ToPrimitiveHint hint) {
@@ -1138,6 +1145,22 @@ MaybeHandle<String> Object::ToString(Isolate* isolate, Handle<Object> input) {
   return ConvertToString(isolate, input);
 }
 
+// static
+MaybeHandle<Object> Object::ToLength(Isolate* isolate, Handle<Object> input) {
+  if (input->IsSmi()) {
+    int value = std::max(Smi::cast(*input)->value(), 0);
+    return handle(Smi::FromInt(value), isolate);
+  }
+  return ConvertToLength(isolate, input);
+}
+
+// static
+MaybeHandle<Object> Object::ToIndex(Isolate* isolate, Handle<Object> input,
+                                    MessageTemplate::Template error_index) {
+  if (input->IsSmi() && Smi::cast(*input)->value() >= 0) return input;
+  return ConvertToIndex(isolate, input, error_index);
+}
+
 bool Object::HasSpecificClassOf(String* name) {
   return this->IsJSObject() && (JSObject::cast(this)->class_name() == name);
 }

src/objects.cc

@@ -203,6 +203,31 @@ MaybeHandle<Name> Object::ConvertToName(Isolate* isolate,
   return ToString(isolate, input);
 }
 
+// ES6 7.1.14
+// static
+MaybeHandle<Object> Object::ConvertToPropertyKey(Isolate* isolate,
+                                                 Handle<Object> value) {
+  // 1. Let key be ToPrimitive(argument, hint String).
+  MaybeHandle<Object> maybe_key =
+      Object::ToPrimitive(value, ToPrimitiveHint::kString);
+  // 2. ReturnIfAbrupt(key).
+  Handle<Object> key;
+  if (!maybe_key.ToHandle(&key)) return key;
+  // 3. If Type(key) is Symbol, then return key.
+  if (key->IsSymbol()) return key;
+  // 4. Return ToString(key).
+  // Extending spec'ed behavior, we'd be happy to return an element index.
+  if (key->IsSmi()) return key;
+  if (key->IsHeapNumber()) {
+    uint32_t uint_value;
+    if (value->ToArrayLength(&uint_value) &&
+        uint_value <= static_cast<uint32_t>(Smi::kMaxValue)) {
+      return handle(Smi::FromInt(static_cast<int>(uint_value)), isolate);
+    }
+  }
+  return Object::ToString(isolate, key);
+}
+
 // static
 MaybeHandle<String> Object::ConvertToString(Isolate* isolate,
                                             Handle<Object> input) {
@@ -383,11 +408,16 @@ Handle<String> Object::NoSideEffectsToString(Isolate* isolate,
 }
 
 // static
-MaybeHandle<Object> Object::ToLength(Isolate* isolate, Handle<Object> input) {
+MaybeHandle<Object> Object::ConvertToLength(Isolate* isolate,
+                                            Handle<Object> input) {
   ASSIGN_RETURN_ON_EXCEPTION(isolate, input, ToNumber(input), Object);
+  if (input->IsSmi()) {
+    int value = std::max(Smi::cast(*input)->value(), 0);
+    return handle(Smi::FromInt(value), isolate);
+  }
   double len = DoubleToInteger(input->Number());
   if (len <= 0.0) {
-    len = 0.0;
+    return handle(Smi::kZero, isolate);
   } else if (len >= kMaxSafeInteger) {
     len = kMaxSafeInteger;
   }
@@ -395,10 +425,12 @@ MaybeHandle<Object> Object::ToLength(Isolate* isolate, Handle<Object> input) {
 }
 
 // static
-MaybeHandle<Object> Object::ToIndex(Isolate* isolate, Handle<Object> input,
-                                    MessageTemplate::Template error_index) {
-  if (input->IsUndefined(isolate)) return isolate->factory()->NewNumber(0.0);
+MaybeHandle<Object> Object::ConvertToIndex(
+    Isolate* isolate, Handle<Object> input,
+    MessageTemplate::Template error_index) {
+  if (input->IsUndefined(isolate)) return handle(Smi::kZero, isolate);
   ASSIGN_RETURN_ON_EXCEPTION(isolate, input, ToNumber(input), Object);
+  if (input->IsSmi() && Smi::cast(*input)->value() >= 0) return input;
   double len = DoubleToInteger(input->Number()) + 0.0;
   auto js_len = isolate->factory()->NewNumber(len);
   if (len < 0.0 || len > kMaxSafeInteger) {
@@ -6493,33 +6525,6 @@ Maybe<bool> JSReceiver::DeletePropertyOrElement(Handle<JSReceiver> object,
   return DeleteProperty(&it, language_mode);
 }
 
-
-// ES6 7.1.14
-// static
-MaybeHandle<Object> Object::ToPropertyKey(Isolate* isolate,
-                                          Handle<Object> value) {
-  // 1. Let key be ToPrimitive(argument, hint String).
-  MaybeHandle<Object> maybe_key =
-      Object::ToPrimitive(value, ToPrimitiveHint::kString);
-  // 2. ReturnIfAbrupt(key).
-  Handle<Object> key;
-  if (!maybe_key.ToHandle(&key)) return key;
-  // 3. If Type(key) is Symbol, then return key.
-  if (key->IsSymbol()) return key;
-  // 4. Return ToString(key).
-  // Extending spec'ed behavior, we'd be happy to return an element index.
-  if (key->IsSmi()) return key;
-  if (key->IsHeapNumber()) {
-    uint32_t uint_value;
-    if (value->ToArrayLength(&uint_value) &&
-        uint_value <= static_cast<uint32_t>(Smi::kMaxValue)) {
-      return handle(Smi::FromInt(static_cast<int>(uint_value)), isolate);
-    }
-  }
-  return Object::ToString(isolate, key);
-}
-
-
 // ES6 19.1.2.4
 // static
 Object* JSReceiver::DefineProperty(Isolate* isolate, Handle<Object> object,

src/objects.h

@@ -1313,15 +1313,15 @@ class Object {
                                               Handle<Object> input);
 
   // ES6 section 7.1.14 ToPropertyKey
-  MUST_USE_RESULT static MaybeHandle<Object> ToPropertyKey(
+  MUST_USE_RESULT static inline MaybeHandle<Object> ToPropertyKey(
       Isolate* isolate, Handle<Object> value);
 
   // ES6 section 7.1.15 ToLength
-  MUST_USE_RESULT static MaybeHandle<Object> ToLength(Isolate* isolate,
-                                                      Handle<Object> input);
+  MUST_USE_RESULT static inline MaybeHandle<Object> ToLength(
+      Isolate* isolate, Handle<Object> input);
 
   // ES6 section 7.1.17 ToIndex
-  MUST_USE_RESULT static MaybeHandle<Object> ToIndex(
+  MUST_USE_RESULT static inline MaybeHandle<Object> ToIndex(
       Isolate* isolate, Handle<Object> input,
       MessageTemplate::Template error_index);
 
@@ -1556,6 +1556,8 @@ class Object {
 
   MUST_USE_RESULT static MaybeHandle<Name> ConvertToName(Isolate* isolate,
                                                          Handle<Object> input);
+  MUST_USE_RESULT static MaybeHandle<Object> ConvertToPropertyKey(
+      Isolate* isolate, Handle<Object> value);
   MUST_USE_RESULT static MaybeHandle<String> ConvertToString(
       Isolate* isolate, Handle<Object> input);
   MUST_USE_RESULT static MaybeHandle<Object> ConvertToNumber(
@@ -1566,6 +1568,12 @@ class Object {
       Isolate* isolate, Handle<Object> input);
   MUST_USE_RESULT static MaybeHandle<Object> ConvertToUint32(
       Isolate* isolate, Handle<Object> input);
+  MUST_USE_RESULT static MaybeHandle<Object> ConvertToLength(
+      Isolate* isolate, Handle<Object> input);
+  MUST_USE_RESULT static MaybeHandle<Object> ConvertToIndex(
+      Isolate* isolate, Handle<Object> input,
+      MessageTemplate::Template error_index);
+
   DISALLOW_IMPLICIT_CONSTRUCTORS(Object);
 };
 

src/regexp/regexp-utils.cc

@@ -174,8 +174,7 @@ MaybeHandle<Object> RegExpUtils::SetAdvancedStringIndex(
 
   ASSIGN_RETURN_ON_EXCEPTION(isolate, last_index_obj,
                              Object::ToLength(isolate, last_index_obj), Object);
-
-  const int last_index = Handle<Smi>::cast(last_index_obj)->value();
+  const int last_index = PositiveNumberToUint32(*last_index_obj);
   const int new_last_index =
       AdvanceStringIndex(isolate, string, last_index, unicode);