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

src/full-codegen.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #include "src/ast.h"
 #include "src/ast-numbering.h"
 #include "src/code-factory.h"
 #include "src/codegen.h"
@@ skipping 405 matching lines @@
   DCHECK(!isolate()->heap()->InNewSpace(*info));
   code->set_type_feedback_info(*info);
 }
 
 
 bool FullCodeGenerator::MustCreateObjectLiteralWithRuntime(
     ObjectLiteral* expr) const {
   // 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;
 }
 
 
 bool FullCodeGenerator::MustCreateArrayLiteralWithRuntime(
     ArrayLiteral* expr) const {
   return expr->depth() > 1 ||
          expr->values()->length() > JSObject::kInitialMaxFastElementArray;
 }
@@ skipping 1411 matching lines @@
   }
   codegen_->PrepareForBailoutForId(exit_id_, NO_REGISTERS);
   codegen_->scope_ = saved_scope_;
 }
 
 
 #undef __
 
 
 } }  // namespace v8::internal