ES6 symbols: Introduce Symbol class, along with abstract Name class

test/cctest/test-symbols.cc

+// Copyright 2013 the V8 project authors. All rights reserved.
+
+// Check that we can traverse very deep stacks of ConsStrings using
+// StringCharacterStram.  Check that Get(int) works on very deep stacks
+// of ConsStrings.  These operations may not be very fast, but they
+// should be possible without getting errors due to too deep recursion.
+
+#include "v8.h"
+
+#include "cctest.h"
+#include "objects.h"
+
+using namespace v8::internal;
+
+static v8::Persistent<v8::Context> env;
+
+static void InitializeVM() {
+  if (env.IsEmpty()) {
+    v8::HandleScope scope;
+    const char* extensions[] = { "v8/print" };
+    v8::ExtensionConfiguration config(1, extensions);
+    env = v8::Context::New(&config);
+  }
+  v8::HandleScope scope;
+  env->Enter();
+}
+
+
+TEST(Create) {
+  InitializeVM();
+  HandleScope scope;
+  Isolate* isolate = Isolate::Current();
+
+  const int kNumSymbols = 30;
+  Handle<Symbol> symbols[kNumSymbols];
+
+  for (int i = 0; i < kNumSymbols; ++i) {
+    symbols[i] = isolate->factory()->NewSymbol();
+    CHECK(symbols[i]->IsName());
+    CHECK(symbols[i]->IsSymbol());
+    CHECK(symbols[i]->HasHashCode());
+    CHECK_GT(symbols[i]->Hash(), 0);
+    symbols[i]->ShortPrint();
+    PrintF("\n");
+#if OBJECT_PRINT
+    symbols[i]->Print();
+#endif
+#if VERIFY_HEAP
+    symbols[i]->Verify();
+#endif
+  }
+
+  HEAP->PerformScavenge();
+  HEAP->CollectAllGarbage(Heap::kNoGCFlags);
+
+  // All symbols should be distinct.
+  for (int i = 0; i < kNumSymbols; ++i) {
+    CHECK(symbols[i]->SameValue(*symbols[i]));
+    for (int j = i + 1; j < kNumSymbols; ++j) {
+      CHECK(!symbols[i]->SameValue(*symbols[j]));
+    }
+  }
+}