[stubs] Add CSA::IsSymbol() and CSA::IsPrivateSymbol().

Review-Url: https://codereview.chromium.org/2571883002
Cr-Commit-Position: refs/heads/master@{#41682}

src/code-stub-assembler.cc

@@ -2915,6 +2915,22 @@ Node* CodeStubAssembler::IsString(Node* object) {
                               Int32Constant(FIRST_NONSTRING_TYPE));
 }
 
+Node* CodeStubAssembler::IsSymbol(Node* object) {
+  return IsSymbolMap(LoadMap(object));
+}
+
+Node* CodeStubAssembler::IsPrivateSymbol(Node* object) {
+  return Select(
+      IsSymbol(object),
+      [=] {
+        Node* const flags =
+            SmiToWord32(LoadObjectField(object, Symbol::kFlagsOffset));
+        const int kPrivateMask = 1 << Symbol::kPrivateBit;
+        return IsSetWord32(flags, kPrivateMask);
+      },
+      [=] { return Int32Constant(0); }, MachineRepresentation::kWord32);
+}
+
 Node* CodeStubAssembler::IsNativeContext(Node* object) {
   return WordEqual(LoadMap(object), LoadRoot(Heap::kNativeContextMapRootIndex));
 }
@@ -4271,10 +4287,10 @@ void CodeStubAssembler::TryToName(Node* key, Label* if_keyisindex,
   Goto(if_keyisindex);
 
   Bind(&if_keyisnotindex);
-  Node* key_instance_type = LoadInstanceType(key);
+  Node* key_map = LoadMap(key);
   // Symbols are unique.
-  GotoIf(Word32Equal(key_instance_type, Int32Constant(SYMBOL_TYPE)),
-         if_keyisunique);
+  GotoIf(IsSymbolMap(key_map), if_keyisunique);
+  Node* key_instance_type = LoadMapInstanceType(key_map);
   // Miss if |key| is not a String.
   STATIC_ASSERT(FIRST_NAME_TYPE == FIRST_TYPE);
   GotoUnless(IsStringInstanceType(key_instance_type), if_bailout);

src/code-stub-assembler.h

@@ -639,6 +639,8 @@ class V8_EXPORT_PRIVATE CodeStubAssembler : public compiler::CodeAssembler {
   Node* IsMap(Node* object);
   Node* IsCallableMap(Node* map);
   Node* IsName(Node* object);
+  Node* IsSymbol(Node* object);
+  Node* IsPrivateSymbol(Node* object);
   Node* IsJSValue(Node* object);
   Node* IsJSArray(Node* object);
   Node* IsNativeContext(Node* object);

test/cctest/test-code-stub-assembler.cc

@@ -2103,5 +2103,52 @@ TEST(AllocatePromiseReactionJobInfo) {
   CHECK(promise_info->debug_name()->IsUndefined(isolate));
 }
 
+TEST(IsSymbol) {
+  Isolate* isolate(CcTest::InitIsolateOnce());
+
+  const int kNumParams = 1;
+  CodeAssemblerTester data(isolate, kNumParams);
+  CodeStubAssembler m(data.state());
+
+  Node* const symbol = m.Parameter(0);
+  m.Return(m.SelectBooleanConstant(m.IsSymbol(symbol)));
+
+  Handle<Code> code = data.GenerateCode();
+  CHECK(!code.is_null());
+
+  FunctionTester ft(code, kNumParams);
+  Handle<Object> result =
+      ft.Call(isolate->factory()->NewSymbol()).ToHandleChecked();
+  CHECK_EQ(isolate->heap()->true_value(), *result);
+
+  result = ft.Call(isolate->factory()->empty_string()).ToHandleChecked();
+  CHECK_EQ(isolate->heap()->false_value(), *result);
+}
+
+TEST(IsPrivateSymbol) {
+  Isolate* isolate(CcTest::InitIsolateOnce());
+
+  const int kNumParams = 1;
+  CodeAssemblerTester data(isolate, kNumParams);
+  CodeStubAssembler m(data.state());
+
+  Node* const symbol = m.Parameter(0);
+  m.Return(m.SelectBooleanConstant(m.IsPrivateSymbol(symbol)));
+
+  Handle<Code> code = data.GenerateCode();
+  CHECK(!code.is_null());
+
+  FunctionTester ft(code, kNumParams);
+  Handle<Object> result =
+      ft.Call(isolate->factory()->NewSymbol()).ToHandleChecked();
+  CHECK_EQ(isolate->heap()->false_value(), *result);
+
+  result = ft.Call(isolate->factory()->empty_string()).ToHandleChecked();
+  CHECK_EQ(isolate->heap()->false_value(), *result);
+
+  result = ft.Call(isolate->factory()->NewPrivateSymbol()).ToHandleChecked();
+  CHECK_EQ(isolate->heap()->true_value(), *result);
+}
+
 }  // namespace internal
 }  // namespace v8