Add GetIdentityHash to v8::Name object API

v8::Object already has GetIdentityHash on it. This change adds its counterpart to v8::Name.

BUG=chromium:437416
LOG=Y

Review URL: https://codereview.chromium.org/753373003

Cr-Commit-Position: refs/heads/master@{#25598}

include/v8.h

@@ -1822,6 +1822,15 @@ class V8_EXPORT Boolean : public Primitive {
  */
 class V8_EXPORT Name : public Primitive {
  public:
+  /**
+   * Returns the identity hash for this object. The current implementation
+   * uses an inline property on the object to store the identity hash.
+   *
+   * The return value will never be 0. Also, it is not guaranteed to be
+   * unique.
+   */
+  int GetIdentityHash();
+
   V8_INLINE static Name* Cast(v8::Value* obj);
  private:
   static void CheckCast(v8::Value* obj);

src/api.cc

@@ -4231,6 +4231,16 @@ Local<v8::Value> Function::GetBoundFunction() const {
 }
 
 
+int Name::GetIdentityHash() {
+  i::Isolate* isolate = Utils::OpenHandle(this)->GetIsolate();
+  ON_BAILOUT(isolate, "v8::Name::GetIdentityHash()", return 0);
+  ENTER_V8(isolate);
+  i::HandleScope scope(isolate);
+  i::Handle<i::Name> self = Utils::OpenHandle(this);
+  return static_cast<int>(self->Hash());
+}
+
+
 int String::Length() const {
   i::Handle<i::String> str = Utils::OpenHandle(this);
   return str->length();

test/cctest/test-api.cc

@@ -3033,6 +3033,53 @@ THREADED_TEST(GlobalProxyIdentityHash) {
 }
 
 
+TEST(SymbolIdentityHash) {
+  LocalContext env;
+  v8::Isolate* isolate = env->GetIsolate();
+  v8::HandleScope scope(isolate);
+
+  {
+    Local<v8::Symbol> symbol = v8::Symbol::New(isolate);
+    int hash = symbol->GetIdentityHash();
+    int hash1 = symbol->GetIdentityHash();
+    CHECK_EQ(hash, hash1);
+    CcTest::heap()->CollectAllGarbage(i::Heap::kNoGCFlags);
+    int hash3 = symbol->GetIdentityHash();
+    CHECK_EQ(hash, hash3);
+  }
+
+  {
+    v8::Handle<v8::Symbol> js_symbol =
+        CompileRun("Symbol('foo')").As<v8::Symbol>();
+    int hash = js_symbol->GetIdentityHash();
+    int hash1 = js_symbol->GetIdentityHash();
+    CHECK_EQ(hash, hash1);
+    CcTest::heap()->CollectAllGarbage(i::Heap::kNoGCFlags);
+    int hash3 = js_symbol->GetIdentityHash();
+    CHECK_EQ(hash, hash3);
+  }
+}
+
+
+TEST(StringIdentityHash) {
+  LocalContext env;
+  v8::Isolate* isolate = env->GetIsolate();
+  v8::HandleScope scope(isolate);
+
+  Local<v8::String> str = v8::String::NewFromUtf8(isolate, "str1");
+  int hash = str->GetIdentityHash();
+  int hash1 = str->GetIdentityHash();
+  CHECK_EQ(hash, hash1);
+  CcTest::heap()->CollectAllGarbage(i::Heap::kNoGCFlags);
+  int hash3 = str->GetIdentityHash();
+  CHECK_EQ(hash, hash3);
+
+  Local<v8::String> str2 = v8::String::NewFromUtf8(isolate, "str1");
+  int hash4 = str2->GetIdentityHash();
+  CHECK_EQ(hash, hash4);
+}
+
+
 THREADED_TEST(SymbolProperties) {
   LocalContext env;
   v8::Isolate* isolate = env->GetIsolate();