Allow NULL classes in inline caches (for example for ==). Fixes a 22x regression with r9762 on a be…

runtime/vm/code_generator.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/code_generator.h"
 
 #include "vm/assembler_macros.h"
 #include "vm/ast.h"
 #include "vm/code_patcher.h"
 #include "vm/compiler.h"
@@ skipping 856 matching lines @@
     // closure calls.
     if (FLAG_trace_ic) {
       OS::Print("InlineCacheMissHandler NULL code for receiver: %s\n",
           receiver.ToCString());
     }
     return Function::null();
   }
   const Function& target_function =
       Function::Handle(target_code.function());
   ASSERT(!target_function.IsNull());
-  if (receiver.IsNull()) {
-    // Null dispatch is slow (e.g., (null).toCString()). The only
-    // fast execution with null receiver is the "==" operator.
-    // Special handling so that we do not pollute the inline cache with null
-    // classes.
-    if (FLAG_trace_ic) {
-      OS::Print("InlineCacheMissHandler Null receiver target %s\n",
-          target_function.ToCString());
-    }
-    return target_function.raw();
-  }
   DartFrameIterator iterator;
   StackFrame* caller_frame = iterator.NextFrame();
   ASSERT(caller_frame != NULL);
   ICData& ic_data = ICData::Handle(
       CodePatcher::GetInstanceCallIcDataAt(caller_frame->pc()));
 #if defined(DEBUG)
   for (intptr_t i = 0; i < ic_data.NumberOfChecks(); i++) {
     GrowableArray<intptr_t> class_ids;
     Function& target = Function::Handle();
     ic_data.GetCheckAt(i, &class_ids, &target);
@@ skipping 729 matching lines @@
       }
     }
   }
   // The cache is null terminated, therefore the loop above should never
   // terminate by itself.
   UNREACHABLE();
   return Code::null();
 }
 
 }  // namespace dart