[turbofan] First step towards sanitizing for-in and making it optimizable.

src/hydrogen.cc

 // Copyright 2013 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/hydrogen.h"
 
 #include <sstream>
 
 #include "src/v8.h"
 
@@ skipping 5183 matching lines @@
   HValue* key =
       Add<HLoadKeyed>(environment()->ExpressionStackAt(2),  // Enum cache.
                       index, index, FAST_ELEMENTS);
 
   if (fast) {
     // Check if the expected map still matches that of the enumerable.
     // If not just deoptimize.
     Add<HCheckMapValue>(enumerable, environment()->ExpressionStackAt(3));
     Bind(each_var, key);
   } else {
-    HValue* function = AddLoadJSBuiltin(Builtins::FILTER_KEY);
     Add<HPushArguments>(enumerable, key);
-    key = Add<HInvokeFunction>(function, 2);
+    Runtime::FunctionId function_id = Runtime::kForInFilter;
+    key = Add<HCallRuntime>(isolate()->factory()->empty_string(),
+                            Runtime::FunctionForId(function_id), 2);
     Bind(each_var, key);
     Add<HSimulate>(stmt->AssignmentId());
-    Add<HCheckHeapObject>(key);
+    IfBuilder if_undefined(this);
+    if_undefined.If<HCompareObjectEqAndBranch>(key,
+                                               graph()->GetConstantUndefined());
+    if_undefined.ThenDeopt(Deoptimizer::kUndefined);
+    if_undefined.End();
   }
 
   BreakAndContinueInfo break_info(stmt, scope(), 5);
   {
     BreakAndContinueScope push(&break_info, this);
     CHECK_BAILOUT(VisitLoopBody(stmt, loop_entry));
   }
 
   HBasicBlock* body_exit =
       JoinContinue(stmt, current_block(), break_info.continue_block());
@@ skipping 7912 matching lines @@
   if (ShouldProduceTraceOutput()) {
     isolate()->GetHTracer()->TraceHydrogen(name(), graph_);
   }
 
 #ifdef DEBUG
   graph_->Verify(false);  // No full verify.
 #endif
 }
 
 } }  // namespace v8::internal