Clean JS function results cache on each major GC.

src/objects-inl.h

Index: src/objects-inl.h
diff --git a/src/objects-inl.h b/src/objects-inl.h
index 59fdd86507591a38c062942d2254fc0942d7088a..4b5e62ce542a6bfe16a470f3940edcf44d0ac0a1 100644
--- a/src/objects-inl.h
+++ b/src/objects-inl.h
@@ -569,6 +569,22 @@ bool Object::IsSymbolTable() {
 }
 
 
+bool Object::IsJSFunctionResultCache() {
+  if (!IsFixedArray()) return false;
+  FixedArray* self = FixedArray::cast(this);
+  int length = self->length();
+  if (length < JSFunctionResultCache::kEntriesIndex) return false;
+  if ((length - JSFunctionResultCache::kEntriesIndex)
+      % JSFunctionResultCache::kEntrySize != 0) {
+    return false;
+  }
+#ifdef DEBUG
+  reinterpret_cast<JSFunctionResultCache*>(this)->JSFunctionResultCacheVerify();
+#endif
+  return true;
+}
+
+
 bool Object::IsCompilationCacheTable() {
   return IsHashTable();
 }
@@ -1594,6 +1610,7 @@ void NumberDictionary::set_requires_slow_elements() {
 CAST_ACCESSOR(FixedArray)
 CAST_ACCESSOR(DescriptorArray)
 CAST_ACCESSOR(SymbolTable)
+CAST_ACCESSOR(JSFunctionResultCache)
 CAST_ACCESSOR(CompilationCacheTable)
 CAST_ACCESSOR(CodeCacheHashTable)
 CAST_ACCESSOR(MapCache)
@@ -1838,6 +1855,20 @@ void ExternalTwoByteString::set_resource(
 }
 
 
+void JSFunctionResultCache::MakeZeroSize() {
+  set(kFingerIndex, Smi::FromInt(kEntriesIndex));
+  set(kCacheSizeIndex, Smi::FromInt(kEntriesIndex));
+}
+
+
+void JSFunctionResultCache::Clear() {
+  int cache_size = Smi::cast(get(kCacheSizeIndex))->value();
+  Object** entries_start = RawField(this, OffsetOfElementAt(kEntriesIndex));
+  MemsetPointer(entries_start, Heap::the_hole_value(), cache_size);
+  MakeZeroSize();
+}
+
+
 byte ByteArray::get(int index) {
   ASSERT(index >= 0 && index < this->length());
   return READ_BYTE_FIELD(this, kHeaderSize + index * kCharSize);