Use the iOS ABI when running SIMARM on Mac or targeting iOS.

runtime/vm/intermediate_language_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"  // Needed here to get TARGET_ARCH_ARM.
 #if defined(TARGET_ARCH_ARM)
 
 #include "vm/intermediate_language.h"
 
 #include "vm/cpu.h"
@@ skipping 2335 matching lines @@
   // R6: iterator which initially points to the start of the variable
   // data area to be initialized.
   // R8: null
   if (num_elements > 0) {
     const intptr_t array_size = instance_size - sizeof(RawArray);
     __ LoadObject(R8, Object::null_object());
     if (num_elements >= 2) {
       __ mov(R9, Operand(R8));
     } else {
 #if defined(DEBUG)
-      // Clobber R7 with an invalid pointer.
+      // Clobber R9 with an invalid pointer.
       __ LoadImmediate(R9, 0x1);
 #endif  // DEBUG
     }
     __ AddImmediate(R6, R0, sizeof(RawArray) - kHeapObjectTag);
     if (array_size < (kInlineArraySize * kWordSize)) {
       __ InitializeFieldsNoBarrierUnrolled(R0, R6, 0, num_elements * kWordSize,
                                            R8, R9);
     } else {
       __ InitializeFieldsNoBarrier(R0, R6, R3, R8, R9);
     }
@@ skipping 4493 matching lines @@
                                 1,
                                 locs());
   __ Drop(1);
   __ Pop(result);
 }
 
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM