Compile FastCloneShallowObjectStub using Crankshaft.

src/hydrogen.h

Index: src/hydrogen.h
diff --git a/src/hydrogen.h b/src/hydrogen.h
index e9b8a2fa836c01e2316a3c884614c497657b7709..de99e8c1f36a7cb05a9191a0ddf20f33391269e2 100644
--- a/src/hydrogen.h
+++ b/src/hydrogen.h
@@ -912,6 +912,28 @@ class HGraphBuilder {
   HInstruction* BuildStoreMap(HValue* object, HValue* map, BailoutId id);
   HInstruction* BuildStoreMap(HValue* object, Handle<Map> map, BailoutId id);
 
+  class CheckBuilder {
+   public:
+    CheckBuilder(HGraphBuilder* builder,
+                 BailoutId id = BailoutId::StubEntry());

[danno, 2013/02/11 14:34:27]

I think it's a good idea to not provide a default. If this builder ever gets
used in an inlined stub in a JS function, then it will need the right ast_id,
and with the default construction it's easy to forget to thread it through. 

[Michael Starzinger, 2013/02/11 16:31:11]

Done (also for the other builders below).

+    ~CheckBuilder() {
+      if (!finished_) End();
+    }
+
+    void CheckNotUndefined(HValue* value);
+    void CheckIntegerEq(HValue* left, HValue* right);
+    void End();
+
+   private:
+    Zone* zone() { return builder_->zone(); }
+
+    HGraphBuilder* builder_;
+    bool finished_;
+    HBasicBlock* failure_block_;
+    HBasicBlock* merge_block_;
+    BailoutId id_;
+  };
+
   class IfBuilder {
    public:
     IfBuilder(HGraphBuilder* builder,
@@ -925,14 +947,14 @@ class HGraphBuilder {
     void End();
 
    private:
+    Zone* zone() { return builder_->zone(); }
+
     HGraphBuilder* builder_;
     bool finished_;
     HBasicBlock* true_block_;
     HBasicBlock* false_block_;
     HBasicBlock* merge_block_;
     BailoutId id_;
-
-    Zone* zone() { return builder_->zone(); }
   };
 
   class LoopBuilder {
@@ -956,6 +978,8 @@ class HGraphBuilder {
     void EndBody();
 
    private:
+    Zone* zone() { return builder_->zone(); }
+
     HGraphBuilder* builder_;
     HValue* context_;
     HInstruction* increment_;
@@ -966,8 +990,6 @@ class HGraphBuilder {
     Direction direction_;
     BailoutId id_;
     bool finished_;
-
-    Zone* zone() { return builder_->zone(); }
   };
 
   HValue* BuildAllocateElements(HContext* context,