Do not allow external strings in old pointer space.

test/cctest/test-api.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 607 matching lines @@
   i::DeleteArray(buf);
   // Large strings should be immediately accepted.
   CHECK(large_string->CanMakeExternal());
 }
 
 
 TEST(MakingExternalUnalignedAsciiString) {
   LocalContext env;
   v8::HandleScope scope(env->GetIsolate());
 
+  CompileRun("function cons(a, b) { return a + b; }"
+             "function slice(a) { return a.substring(1); }");
   // Create a cons string that will land in old pointer space.
-  Local<String> string = Local<String>::Cast(CompileRun(
-      "function cons(a, b) { return a + b; }"
+  Local<String> cons = Local<String>::Cast(CompileRun(
       "cons('abcdefghijklm', 'nopqrstuvwxyz');"));
+  // Create a sliced string that will land in old pointer space.
+  Local<String> slice = Local<String>::Cast(CompileRun(
+      "slice('abcdefghijklmnopqrstuvwxyz');"));
 
   // Trigger GCs so that the newly allocated string moves to old gen.
   SimulateFullSpace(HEAP->old_pointer_space());
   HEAP->CollectGarbage(i::NEW_SPACE);  // in survivor space now
   HEAP->CollectGarbage(i::NEW_SPACE);  // in old gen now
 
   // Turn into external string with unaligned resource data.
   int dispose_count = 0;
-  const char* c_source = "_abcdefghijklmnopqrstuvwxyz";
-  bool success = string->MakeExternal(
-      new TestAsciiResource(i::StrDup(c_source) + 1, &dispose_count));
+  const char* c_cons = "_abcdefghijklmnopqrstuvwxyz";
+  bool success = cons->MakeExternal(
+      new TestAsciiResource(i::StrDup(c_cons) + 1, &dispose_count));
+  CHECK(success);
+  const char* c_slice = "_bcdefghijklmnopqrstuvwxyz";
+  success = slice->MakeExternal(
+      new TestAsciiResource(i::StrDup(c_slice) + 1, &dispose_count));
   CHECK(success);
 
   // Trigger GCs and force evacuation.
   HEAP->CollectAllGarbage(i::Heap::kNoGCFlags);
   HEAP->CollectAllGarbage(i::Heap::kReduceMemoryFootprintMask);
 }
 
 
 THREADED_TEST(UsingExternalString) {
   i::Factory* factory = i::Isolate::Current()->factory();
@@ skipping 19271 matching lines @@
   CheckCorrectThrow("%HasProperty(other, 'x')");
   CheckCorrectThrow("%HasElement(other, 1)");
   CheckCorrectThrow("%IsPropertyEnumerable(other, 'x')");
   CheckCorrectThrow("%GetPropertyNames(other)");
   CheckCorrectThrow("%GetLocalPropertyNames(other, true)");
   CheckCorrectThrow("%DefineOrRedefineAccessorProperty("
                         "other, 'x', null, null, 1)");
 }
 
 #endif  // WIN32