[turbofan] Use FastCloneShallow[Array|Object]Stub if possible.

src/full-codegen.cc

Index: src/full-codegen.cc
diff --git a/src/full-codegen.cc b/src/full-codegen.cc
index 6acfb97de3a5321b91d9d22a3c0d2de4f2f9535b..b470a7a3e4655c892084c26e957c10fba71b820b 100644
--- a/src/full-codegen.cc
+++ b/src/full-codegen.cc
@@ -423,10 +423,9 @@ bool FullCodeGenerator::MustCreateObjectLiteralWithRuntime(
   // FastCloneShallowObjectStub doesn't copy elements, and object literals don't
   // support copy-on-write (COW) elements for now.
   // TODO(mvstanton): make object literals support COW elements.
-  return expr->may_store_doubles() || expr->depth() > 1 ||
-         masm()->serializer_enabled() ||
+  return masm()->serializer_enabled() ||
+         expr->ComputeFlags() != ObjectLiteral::kShallowProperties ||

[titzer, 2015/04/21 14:02:26]

Is ComputeFlags() expensive enough to need a cache?

[Michael Starzinger, 2015/04/21 14:35:41]

Done.

          expr->ComputeFlags() != ObjectLiteral::kFastElements ||
-         expr->has_elements() ||
          expr->properties_count() >
              FastCloneShallowObjectStub::kMaximumClonedProperties;
 }