Internalize strings in-place

src/compiler/access-builder.cc

Index: src/compiler/access-builder.cc
diff --git a/src/compiler/access-builder.cc b/src/compiler/access-builder.cc
index 9fd531c637f45583a7684d440d5f28b3880c6d7c..848d02b90f44f75f43d9770cc2662686b3a67d91 100644
--- a/src/compiler/access-builder.cc
+++ b/src/compiler/access-builder.cc
@@ -521,6 +521,15 @@ FieldAccess AccessBuilder::ForConsStringSecond() {
 }
 
 // static
+FieldAccess AccessBuilder::ForThinStringActual() {
+  FieldAccess access = {kTaggedBase,         ThinString::kActualOffset,
+                        Handle<Name>(),      MaybeHandle<Map>(),
+                        Type::String(),      MachineType::TaggedPointer(),
+                        kPointerWriteBarrier};
+  return access;
+}
+
+// static
 FieldAccess AccessBuilder::ForSlicedStringOffset() {
   FieldAccess access = {kTaggedBase,         SlicedString::kOffsetOffset,
                         Handle<Name>(),      MaybeHandle<Map>(),