Add "own" symbols support.

"Own" symbols are symbols that can only denote own properties of
objects.

R=verwaest@chromium.org

Review URL: https://codereview.chromium.org/464473002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23056 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/factory.cc

@@ -664,6 +664,14 @@ Handle<Symbol> Factory::NewPrivateSymbol() {
 }
 
 
+Handle<Symbol> Factory::NewPrivateOwnSymbol() {
+  Handle<Symbol> symbol = NewSymbol();
+  symbol->set_is_private(true);
+  symbol->set_is_own(true);
+  return symbol;
+}
+
+
 Handle<Context> Factory::NewNativeContext() {
   Handle<FixedArray> array = NewFixedArray(Context::NATIVE_CONTEXT_SLOTS);
   array->set_map_no_write_barrier(*native_context_map());

src/factory.h

@@ -221,6 +221,7 @@ class Factory V8_FINAL {
   // Create a symbol.
   Handle<Symbol> NewSymbol();
   Handle<Symbol> NewPrivateSymbol();
+  Handle<Symbol> NewPrivateOwnSymbol();
 
   // Create a global (but otherwise uninitialized) context.
   Handle<Context> NewNativeContext();

src/lookup.h

@@ -47,7 +47,7 @@ class LookupIterator V8_FINAL BASE_EMBEDDED {
   LookupIterator(Handle<Object> receiver,
                  Handle<Name> name,
                  Configuration configuration = CHECK_ALL)
-      : configuration_(configuration),
+      : configuration_(ComputeConfiguration(configuration, name)),
         state_(NOT_FOUND),
         property_kind_(DATA),
         property_encoding_(DESCRIPTOR),
@@ -66,7 +66,7 @@ class LookupIterator V8_FINAL BASE_EMBEDDED {
                  Handle<Name> name,
                  Handle<JSReceiver> holder,
                  Configuration configuration = CHECK_ALL)
-      : configuration_(configuration),
+      : configuration_(ComputeConfiguration(configuration, name)),
         state_(NOT_FOUND),
         property_kind_(DATA),
         property_encoding_(DESCRIPTOR),
@@ -187,6 +187,15 @@ class LookupIterator V8_FINAL BASE_EMBEDDED {
     return number_;
   }
 
+  static Configuration ComputeConfiguration(
+      Configuration configuration, Handle<Name> name) {
+    if (name->IsOwn()) {
+      return static_cast<Configuration>(configuration & CHECK_OWN);
+    } else {
+      return configuration;
+    }
+  }
+
   Configuration configuration_;
   State state_;
   bool has_property_;

src/objects-inl.h

@@ -3372,6 +3372,7 @@ bool Name::Equals(Handle<Name> one, Handle<Name> two) {
 ACCESSORS(Symbol, name, Object, kNameOffset)
 ACCESSORS(Symbol, flags, Smi, kFlagsOffset)
 BOOL_ACCESSORS(Symbol, flags, is_private, kPrivateBit)
+BOOL_ACCESSORS(Symbol, flags, is_own, kOwnBit)
 
 
 bool String::Equals(String* other) {
@@ -6496,6 +6497,10 @@ uint32_t Name::Hash() {
   return String::cast(this)->ComputeAndSetHash();
 }
 
+bool Name::IsOwn() {
+  return this->IsSymbol() && Symbol::cast(this)->is_own();
+}
+
 
 StringHasher::StringHasher(int length, uint32_t seed)
   : length_(length),

src/objects-printer.cc

@@ -430,7 +430,8 @@ void Symbol::SymbolPrint(OStream& os) {  // NOLINT
   HeapObject::PrintHeader(os, "Symbol");
   os << " - hash: " << Hash();
   os << "\n - name: " << Brief(name());
-  os << " - private: " << is_private();
+  os << "\n - private: " << is_private();
+  os << "\n - own: " << is_own();
   os << "\n";
 }
 

src/objects.cc

@@ -3560,6 +3560,11 @@ void JSObject::LookupRealNamedProperty(Handle<Name> name,
 
 void JSObject::LookupRealNamedPropertyInPrototypes(Handle<Name> name,
                                                    LookupResult* result) {
+  if (name->IsOwn()) {
+    result->NotFound();
+    return;
+  }
+
   DisallowHeapAllocation no_gc;
   Isolate* isolate = GetIsolate();
   for (PrototypeIterator iter(isolate, this); !iter.IsAtEnd(); iter.Advance()) {
@@ -6107,7 +6112,7 @@ void JSReceiver::LookupOwn(
   }
 
   js_object->LookupOwnRealNamedProperty(name, result);
-  if (result->IsFound() || !search_hidden_prototypes) return;
+  if (result->IsFound() || name->IsOwn() || !search_hidden_prototypes) return;
 
   PrototypeIterator iter(GetIsolate(), js_object);
   if (!iter.GetCurrent()->IsJSReceiver()) return;
@@ -6126,6 +6131,10 @@ void JSReceiver::Lookup(Handle<Name> name, LookupResult* result) {
        !iter.IsAtEnd(); iter.Advance()) {
     JSReceiver::cast(iter.GetCurrent())->LookupOwn(name, result, false);
     if (result->IsFound()) return;
+    if (name->IsOwn()) {
+      result->NotFound();
+      return;
+    }
   }
   result->NotFound();
 }

src/objects.h

@@ -8954,6 +8954,9 @@ class Name: public HeapObject {
   // Conversion.
   inline bool AsArrayIndex(uint32_t* index);
 
+  // Whether name can only name own properties.
+  inline bool IsOwn();
+
   DECLARE_CAST(Name)
 
   DECLARE_PRINTER(Name)
@@ -9029,6 +9032,10 @@ class Symbol: public Name {
   // [is_private]: whether this is a private symbol.
   DECL_BOOLEAN_ACCESSORS(is_private)
 
+  // [is_own]: whether this is an own symbol, that is, only used to designate
+  // own properties of objects.
+  DECL_BOOLEAN_ACCESSORS(is_own)
+
   DECLARE_CAST(Symbol)
 
   // Dispatched behavior.
@@ -9044,6 +9051,7 @@ class Symbol: public Name {
 
  private:
   static const int kPrivateBit = 0;
+  static const int kOwnBit = 1;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(Symbol);
 };

src/runtime.cc

@@ -608,6 +608,17 @@ RUNTIME_FUNCTION(Runtime_CreatePrivateSymbol) {
 }
 
 
+RUNTIME_FUNCTION(Runtime_CreatePrivateOwnSymbol) {
+  HandleScope scope(isolate);
+  DCHECK(args.length() == 1);
+  CONVERT_ARG_HANDLE_CHECKED(Object, name, 0);
+  RUNTIME_ASSERT(name->IsString() || name->IsUndefined());
+  Handle<Symbol> symbol = isolate->factory()->NewPrivateOwnSymbol();
+  if (name->IsString()) symbol->set_name(*name);
+  return *symbol;
+}
+
+
 RUNTIME_FUNCTION(Runtime_CreateGlobalPrivateSymbol) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 1);

src/runtime.h

@@ -260,6 +260,7 @@ namespace internal {
   F(CreateSymbol, 1, 1)                                               \
   F(CreatePrivateSymbol, 1, 1)                                        \
   F(CreateGlobalPrivateSymbol, 1, 1)                                  \
+  F(CreatePrivateOwnSymbol, 1, 1)                                     \
   F(NewSymbolWrapper, 1, 1)                                           \
   F(SymbolDescription, 1, 1)                                          \
   F(SymbolRegistry, 0, 1)                                             \

test/mjsunit/own-symbols.js

+// Copyright 2014 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+//
+// Flags: --allow-natives-syntax
+
+var s = %CreatePrivateOwnSymbol("s");
+var s1 = %CreatePrivateOwnSymbol("s1");
+
+function TestSimple() {
+  var p = {}
+  p[s] = "moo";
+
+  var o = Object.create(p);
+
+  assertEquals(undefined, o[s]);
+  assertEquals("moo", p[s]);
+
+  o[s] = "bow-wow";
+  assertEquals("bow-wow", o[s]);
+  assertEquals("moo", p[s]);
+}
+
+TestSimple();
+
+
+function TestICs() {
+  var p = {}
+  p[s] = "moo";
+
+
+  var o = Object.create(p);
+  o[s1] = "bow-wow";
+  function checkNonOwn(o) {
+    assertEquals(undefined, o[s]);
+    assertEquals("bow-wow", o[s1]);
+  }
+
+  checkNonOwn(o);
+
+  // Test monomorphic/optimized.
+  for (var i = 0; i < 1000; i++) {
+    checkNonOwn(o);
+  }
+
+  // Test non-monomorphic.
+  for (var i = 0; i < 1000; i++) {
+    var oNew = Object.create(p);
+    oNew["s" + i] = i;
+    oNew[s1] = "bow-wow";
+    checkNonOwn(oNew);
+  }
+}
+
+TestICs();

test/mjsunit/runtime-gen/createprivateownsymbol.js

+// Copyright 2014 the V8 project authors. All rights reserved.
+// AUTO-GENERATED BY tools/generate-runtime-tests.py, DO NOT MODIFY
+// Flags: --allow-natives-syntax --harmony --harmony-proxies
+var arg0 = "foo";
+%CreatePrivateOwnSymbol(arg0);

tools/generate-runtime-tests.py

@@ -47,8 +47,8 @@ EXPAND_MACROS = [
 # that the parser doesn't bit-rot. Change the values as needed when you add,
 # remove or change runtime functions, but make sure we don't lose our ability
 # to parse them!
-EXPECTED_FUNCTION_COUNT = 428
-EXPECTED_FUZZABLE_COUNT = 331
+EXPECTED_FUNCTION_COUNT = 429
+EXPECTED_FUZZABLE_COUNT = 332
 EXPECTED_CCTEST_COUNT = 7
 EXPECTED_UNKNOWN_COUNT = 16
 EXPECTED_BUILTINS_COUNT = 809
@@ -226,6 +226,7 @@ CUSTOM_KNOWN_GOOD_INPUT = {
   "CreateBreakIterator": ["'en-US'", "{type: 'string'}", None, None],
   "CreateJSFunctionProxy": [None, "function() {}", None, None, None],
   "CreatePrivateSymbol": ["\"foo\"", None],
+  "CreatePrivateOwnSymbol": ["\"foo\"", None],
   "CreateSymbol": ["\"foo\"", None],
   "DateParseString": [None, "new Array(8)", None],
   "DefineAccessorPropertyUnchecked": [None, None, "function() {}",