Remove signature classes from the VM.

runtime/vm/intrinsifier_arm64.cc

 // Copyright (c) 2014, 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/globals.h"  // Needed here to get TARGET_ARCH_ARM64.
 #if defined(TARGET_ARCH_ARM64)
 
 #include "vm/intrinsifier.h"
 
 #include "vm/assembler.h"
@@ skipping 1596 matching lines @@
   __ csel(R0, TMP, R0, EQ);
   __ ret();
 }
 
 
 // Return type quickly for simple types (not parameterized and not signature).
 void Intrinsifier::ObjectRuntimeType(Assembler* assembler) {
   Label fall_through;
   __ ldr(R0, Address(SP, 0 * kWordSize));
   __ LoadClassIdMayBeSmi(R1, R0);
+  __ CompareImmediate(R1, kClosureCid);
+  __ b(&fall_through, EQ);  // Instance is a closure.
   __ LoadClassById(R2, R1);
   // R2: class of instance (R0).
-  __ ldr(R3, FieldAddress(R2, Class::signature_function_offset()));
-  __ CompareObject(R3, Object::null_object());
-  __ b(&fall_through, NE);
 
   __ ldr(R3, FieldAddress(R2, Class::num_type_arguments_offset()), kHalfword);
   __ CompareImmediate(R3, 0);
   __ b(&fall_through, NE);
 
   __ ldr(R0, FieldAddress(R2, Class::canonical_types_offset()));
   __ CompareObject(R0, Object::null_object());
   __ b(&fall_through, EQ);
   __ ret();
 
@@ skipping 566 matching lines @@
 
 void Intrinsifier::Profiler_getCurrentTag(Assembler* assembler) {
   __ LoadIsolate(R0);
   __ ldr(R0, Address(R0, Isolate::current_tag_offset()));
   __ ret();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM64