Promote and inflate string slices during scavenging GC.

test/cctest/test-strings.cc

Index: test/cctest/test-strings.cc
diff --git a/test/cctest/test-strings.cc b/test/cctest/test-strings.cc
index 55c21417d0edeb5df29090f3280ac9580cc003bd..a94aa84ff98e59e4886dd90cbdc6045e69919847 100644
--- a/test/cctest/test-strings.cc
+++ b/test/cctest/test-strings.cc
@@ -558,3 +558,35 @@ TEST(SliceFromSlice) {
   CHECK(SlicedString::cast(*string)->parent()->IsSeqString());
   CHECK_EQ("cdefghijklmnopqrstuvwx", *(string->ToCString()));
 }
+
+
+TEST(SliceConversion) {
+  // This tests whether a slice promoted during scavenging is properly
+  // converted to a sequential string when being copied into old space.
+  FLAG_string_slices = true;
+  InitializeVM();
+  HandleScope scope;
+  v8::Local<v8::Value> result;
+  Handle<String> string;
+  const char* init = "var str = 'abcdefghijklmnopqrstuvwxyz';";
+  const char* slice = "str.slice(2,24)";
+  const char* fill_new_space =
+      "var fill = [];"
+      "for (var i = 0; i < 100000; i++) fill.push(i + ' ');";
+
+  CompileRun(init);
+
+  result = CompileRun(slice);
+  CHECK(result->IsString());
+  string = v8::Utils::OpenHandle(v8::String::Cast(*result));
+  CHECK(HEAP->InNewSpace(*string));
+  CHECK(string->IsSlicedString());
+  CHECK_EQ("cdefghijklmnopqrstuvwx", *(string->ToCString()));
+
+  CompileRun(fill_new_space);
+  HEAP->PerformScavenge();
+
+  CHECK(!HEAP->InNewSpace(*string));
+  CHECK(string->IsSeqString());
+  CHECK_EQ("cdefghijklmnopqrstuvwx", *(string->ToCString()));
+}