Remove signature classes from the VM.

runtime/vm/intrinsifier_x64.cc

 // Copyright (c) 2013, 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_X64.
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/intrinsifier.h"
 
 #include "vm/assembler.h"
@@ skipping 1518 matching lines @@
 }
 
 
 // Return type quickly for simple types (not parameterized and not signature).
 void Intrinsifier::ObjectRuntimeType(Assembler* assembler) {
   Label fall_through;
   __ movq(RAX, Address(RSP, + 1 * kWordSize));
   __ LoadClassIdMayBeSmi(RCX, RAX);
 
   // RCX: untagged cid of instance (RAX).
+  __ cmpq(RCX, Immediate(kClosureCid));
+  __ j(EQUAL, &fall_through, Assembler::kNearJump);  // Instance is a closure.
+
   __ LoadClassById(RDI, RCX);
   // RDI: class of instance (RAX).
-  __ movq(RCX, FieldAddress(RDI, Class::signature_function_offset()));
-  __ CompareObject(RCX, Object::null_object());
-  __ j(NOT_EQUAL, &fall_through, Assembler::kNearJump);
 
   __ movzxw(RCX, FieldAddress(RDI, Class::num_type_arguments_offset()));
   __ cmpq(RCX, Immediate(0));
   __ j(NOT_EQUAL, &fall_through, Assembler::kNearJump);
   __ movq(RAX, FieldAddress(RDI, Class::canonical_types_offset()));
   __ CompareObject(RAX, Object::null_object());
   __ j(EQUAL, &fall_through, Assembler::kNearJump);  // Not yet set.
   __ ret();
 
   __ Bind(&fall_through);
@@ skipping 554 matching lines @@
   __ LoadIsolate(RAX);
   __ movq(RAX, Address(RAX, Isolate::current_tag_offset()));
   __ ret();
 }
 
 #undef __
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64