Gentle start with removing explicit interfaces

runtime/vm/flow_graph_compiler_x64.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/globals.h"  // Needed here to get TARGET_ARCH_X64.
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/flow_graph_compiler.h"
 
 #include "lib/error.h"
@@ skipping 223 matching lines @@
     __ j(EQUAL, is_instance_lbl);
   }
   // Bool interface can be implemented only by core class Bool.
   // (see ClassFinalizer::ResolveInterfaces for list of restricted interfaces).
   if (type.IsBoolInterface()) {
     __ cmpl(kClassIdReg, Immediate(kBoolCid));
     __ j(EQUAL, is_instance_lbl);
     __ jmp(is_not_instance_lbl);
     return false;
   }
-  if (type.IsFunctionInterface()) {
+  if (type.IsFunctionType()) {
     // Check if instance is a closure.
     const Immediate raw_null =
         Immediate(reinterpret_cast<intptr_t>(Object::null()));
     __ LoadClassById(R13, kClassIdReg);
     __ movq(R13, FieldAddress(R13, Class::signature_function_offset()));
     __ cmpq(R13, raw_null);
     __ j(NOT_EQUAL, is_instance_lbl);
     __ jmp(is_not_instance_lbl);
     return false;
   }
   // Custom checking for numbers (Smi, Mint, Bigint and Double).
   // Note that instance is not Smi (checked above).
-  if (type.IsSubtypeOf(Type::Handle(Type::NumberInterface()), NULL)) {
+  if (type.IsSubtypeOf(Type::Handle(Type::Number()), NULL)) {
     GenerateNumberTypeCheck(
         kClassIdReg, type, is_instance_lbl, is_not_instance_lbl);
     return false;
   }
   if (type.IsStringInterface()) {
     GenerateStringTypeCheck(kClassIdReg, is_instance_lbl, is_not_instance_lbl);
     return false;
   }
   // Otherwise fallthrough.
   return true;
@@ skipping 68 matching lines @@
     const Type& object_type = Type::ZoneHandle(Type::ObjectType());
     __ CompareObject(RDI, object_type);
     __ j(EQUAL,  is_instance_lbl);
 
     // For Smi check quickly against int and num interfaces.
     Label not_smi;
     __ testq(RAX, Immediate(kSmiTagMask));  // Value is Smi?
     __ j(NOT_ZERO, &not_smi, Assembler::kNearJump);
     __ CompareObject(RDI, Type::ZoneHandle(Type::IntInterface()));
     __ j(EQUAL,  is_instance_lbl);
-    __ CompareObject(RDI, Type::ZoneHandle(Type::NumberInterface()));
+    __ CompareObject(RDI, Type::ZoneHandle(Type::Number()));
     __ j(EQUAL,  is_instance_lbl);
     // Smi must be handled in runtime.
     __ jmp(&fall_through);
 
     __ Bind(&not_smi);
     // RDX: instantiator type arguments.
     // RAX: instance.
     const Register kInstanceReg = RAX;
     const Register kTypeArgumentsReg = RDX;
     const Register kTempReg = R10;
@@ skipping 863 matching lines @@
 void ParallelMoveResolver::Exchange(const Address& mem1, const Address& mem2) {
   __ Exchange(mem1, mem2);
 }
 
 
 #undef __
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64