ARM & MIPS: Don't embed an address in the general class id fetch.

runtime/vm/assembler_arm.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"  // NOLINT
 #if defined(TARGET_ARCH_ARM)
 
 #include "vm/assembler.h"
 #include "vm/cpu.h"
 #include "vm/longjump.h"
@@ skipping 1991 matching lines @@
 
 void Assembler::CompareClassId(Register object,
                                intptr_t class_id,
                                Register scratch) {
   LoadClassId(scratch, object);
   CompareImmediate(scratch, class_id);
 }
 
 
 void Assembler::LoadClassIdMayBeSmi(Register result, Register object) {
-  static const intptr_t kSmiCidSource = kSmiCid << RawObject::kClassIdTagPos;
-
-  LoadImmediate(TMP, reinterpret_cast<int32_t>(&kSmiCidSource) + 1);
   tst(object, Operand(kSmiTagMask));
-  mov(TMP, Operand(object), NE);
-  LoadClassId(result, TMP);
+  LoadClassId(result, object, NE);
+  LoadImmediate(result, kSmiCid, EQ);
 }
 
 
 void Assembler::LoadTaggedClassIdMayBeSmi(Register result, Register object) {
   LoadClassIdMayBeSmi(result, object);
   SmiTag(result);
 }
 
 
 void Assembler::ComputeRange(Register result,
@@ skipping 1638 matching lines @@
 
 
 const char* Assembler::FpuRegisterName(FpuRegister reg) {
   ASSERT((0 <= reg) && (reg < kNumberOfFpuRegisters));
   return fpu_reg_names[reg];
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM