Support %_IsObject in Crankshaft.

src/hydrogen.cc

Index: src/hydrogen.cc
===================================================================
--- src/hydrogen.cc	(revision 5982)
+++ src/hydrogen.cc	(working copy)
@@ -4948,17 +4948,21 @@
 }
 
 
+void HGraphBuilder::GenerateIsObject(int argument_count, int ast_id) {
+  ASSERT(argument_count == 1);
+
+  HValue* value = Pop();
+  HIsObject* test = new HIsObject(value);
+  ast_context()->ReturnInstruction(test, ast_id);
+}
+
+
 void HGraphBuilder::GenerateIsNonNegativeSmi(int argument_count,
                                              int ast_id) {
   BAILOUT("inlined runtime function: IsNonNegativeSmi");
 }
 
 
-void HGraphBuilder::GenerateIsObject(int argument_count, int ast_id) {
-  BAILOUT("inlined runtime function: IsObject");
-}
-
-
 void HGraphBuilder::GenerateIsUndetectableObject(int argument_count,
                                                  int ast_id) {
   BAILOUT("inlined runtime function: IsUndetectableObject");