In-heap small typed arrays

src/heap.h

Index: src/heap.h
diff --git a/src/heap.h b/src/heap.h
index 1ac4dfaa0808848947834983bd862aa0fc9f44d2..1c6cba912ffede2d490e325aad1370a37d02cce5 100644
--- a/src/heap.h
+++ b/src/heap.h
@@ -164,6 +164,16 @@ namespace internal {
   V(Map, fixed_float32_array_map, FixedFloat32ArrayMap)                        \
   V(Map, fixed_float64_array_map, FixedFloat64ArrayMap)                        \
   V(Map, fixed_uint8_clamped_array_map, FixedUint8ClampedArrayMap)             \
+  V(FixedTypedArrayBase, empty_fixed_uint8_array, EmptyFixedUint8Array)        \
+  V(FixedTypedArrayBase, empty_fixed_int8_array, EmptyFixedInt8Array)          \
+  V(FixedTypedArrayBase, empty_fixed_uint16_array, EmptyFixedUint16Array)      \
+  V(FixedTypedArrayBase, empty_fixed_int16_array, EmptyFixedInt16Array)        \
+  V(FixedTypedArrayBase, empty_fixed_uint32_array, EmptyFixedUint32Array)      \
+  V(FixedTypedArrayBase, empty_fixed_int32_array, EmptyFixedInt32Array)        \
+  V(FixedTypedArrayBase, empty_fixed_float32_array, EmptyFixedFloat32Array)    \
+  V(FixedTypedArrayBase, empty_fixed_float64_array, EmptyFixedFloat64Array)    \
+  V(FixedTypedArrayBase, empty_fixed_uint8_clamped_array,                      \
+      EmptyFixedUint8ClampedArray)                                             \
   V(Map, non_strict_arguments_elements_map, NonStrictArgumentsElementsMap)     \
   V(Map, function_context_map, FunctionContextMap)                             \
   V(Map, catch_context_map, CatchContextMap)                                   \
@@ -1637,7 +1647,9 @@ class Heap {
       ExternalArrayType array_type);
 
   RootListIndex RootIndexForEmptyExternalArray(ElementsKind kind);
+  RootListIndex RootIndexForEmptyFixedTypedArray(ElementsKind kind);
   ExternalArray* EmptyExternalArrayForMap(Map* map);
+  FixedTypedArrayBase* EmptyFixedTypedArrayForMap(Map* map);
 
   void RecordStats(HeapStats* stats, bool take_snapshot = false);
 
@@ -2211,6 +2223,10 @@ class Heap {
   MUST_USE_RESULT MaybeObject* AllocateEmptyExternalArray(
       ExternalArrayType array_type);
 
+  // Allocate empty fixed typed array of given type.
+  MUST_USE_RESULT MaybeObject* AllocateEmptyFixedTypedArray(
+      ExternalArrayType array_type);
+
   // Allocate empty fixed double array.
   MUST_USE_RESULT MaybeObject* AllocateEmptyFixedDoubleArray();