The detailed heap snapshot generator was slightly adjusted for tracking sliced strings.

BUG=v8:1779
TEST=cctest/test-heap-profiler/HeapSnapshotSlicedString

Review URL: http://codereview.chromium.org/8362028
Patch from Ilya Tikhonovsky <loislo@chromium.org>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@9742 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/profile-generator.cc

@@ -1951,6 +1951,10 @@ void V8HeapExplorer::ExtractReferences(HeapObject* obj) {
       SetInternalReference(obj, entry, 1, cs->first());
       SetInternalReference(obj, entry, 2, cs->second());
     }
+    if (obj->IsSlicedString()) {
+      SlicedString* ss = SlicedString::cast(obj);
+      SetInternalReference(obj, entry, "parent", ss->parent());
+    }
     extract_indexed_refs = false;
   } else if (obj->IsGlobalContext()) {
     Context* context = Context::cast(obj);

test/cctest/test-heap-profiler.cc

@@ -252,6 +252,28 @@ TEST(HeapSnapshotHeapNumbers) {
   CHECK_EQ(v8::HeapGraphNode::kHeapNumber, b->GetType());
 }
 
+TEST(HeapSnapshotSlicedString) {
+  v8::HandleScope scope;
+  LocalContext env;
+  CompileRun(
+      "parent_string = \"123456789.123456789.123456789.123456789.123456789."
+      "123456789.123456789.123456789.123456789.123456789."
+      "123456789.123456789.123456789.123456789.123456789."
+      "123456789.123456789.123456789.123456789.123456789.\";"
+      "child_string = parent_string.slice(100);");
+  const v8::HeapSnapshot* snapshot =
+      v8::HeapProfiler::TakeSnapshot(v8_str("strings"));
+  const v8::HeapGraphNode* global = GetGlobalObject(snapshot);
+  const v8::HeapGraphNode* parent_string =
+      GetProperty(global, v8::HeapGraphEdge::kShortcut, "parent_string");
+  CHECK_NE(NULL, parent_string);
+  const v8::HeapGraphNode* child_string =
+      GetProperty(global, v8::HeapGraphEdge::kShortcut, "child_string");
+  CHECK_NE(NULL, child_string);
+  const v8::HeapGraphNode* parent =
+      GetProperty(child_string, v8::HeapGraphEdge::kInternal, "parent");
+  CHECK_EQ(parent_string, parent);
+}
 
 TEST(HeapSnapshotInternalReferences) {
   v8::HandleScope scope;