Dart VM: Simplify code generation for equality operators.

runtime/lib/function.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/bootstrap_natives.h"
 
 #include "vm/compiler.h"
 #include "vm/dart_entry.h"
 #include "vm/exceptions.h"
 #include "vm/native_entry.h"
@@ skipping 15 matching lines @@
   }
   return result.raw();
 }
 
 
 DEFINE_NATIVE_ENTRY(FunctionImpl_equals, 2) {
   const Instance& receiver = Instance::CheckedHandle(
       isolate, arguments->NativeArgAt(0));
   ASSERT(receiver.IsClosure());
   GET_NATIVE_ARGUMENT(Instance, other, arguments->NativeArgAt(1));
+  ASSERT(!other.IsNull());
   if (receiver.raw() == other.raw()) return Bool::True().raw();
   if (other.IsClosure()) {
     const Function& func_a = Function::Handle(Closure::function(receiver));
     const Function& func_b = Function::Handle(Closure::function(other));
     if (func_a.raw() == func_b.raw()) {
       ASSERT(!func_a.IsImplicitStaticClosureFunction());
       if (func_a.IsImplicitInstanceClosureFunction()) {
         const Context& context_a = Context::Handle(Closure::context(receiver));
         const Context& context_b = Context::Handle(Closure::context(other));
         const Instance& receiver_a = Instance::Handle(context_a.At(0));
@@ skipping 21 matching lines @@
     result ^= result >> 11;
     result += result << 15;
     result &= ((static_cast<intptr_t>(1) << String::kHashBits) - 1);
     return Smi::New(result);
   }
   UNREACHABLE();
   return Object::null();
 }
 
 }  // namespace dart