Adds support for building arm64 Android.

runtime/vm/cpu_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"
 
 #if defined(TARGET_ARCH_ARM64)
 
 #include "vm/cpu.h"
 #include "vm/cpuinfo.h"
 #include "vm/simulator.h"
 
 #if defined(HOST_ARCH_ARM64)
 #include <sys/syscall.h>  /* NOLINT */
 #include <unistd.h>  /* NOLINT */
 #endif
 
 namespace dart {
 
 void CPU::FlushICache(uword start, uword size) {
 #if defined(HOST_ARCH_ARM64)
   // Nothing to do. Flushing no instructions.
   if (size == 0) {
     return;
   }
 
-  // ARM recommends using the gcc intrinsic __clear_cache on Linux, and the
-  // library call cacheflush from unistd.h on Android:
+  // ARM recommends using the gcc intrinsic __clear_cache on Linux and Android.
   // blogs.arm.com/software-enablement/141-caches-and-self-modifying-code/
-  #if defined(__linux__) && !defined(ANDROID)
+  #if defined(__linux__) || defined(ANDROID)
     extern void __clear_cache(char*, char*);
     char* beg = reinterpret_cast<char*>(start);
     char* end = reinterpret_cast<char*>(start + size);
     ::__clear_cache(beg, end);
-  #elif defined(ANDROID)
-    // TODO(zra): Verify that this is correct for arm64 in addition to arm.
-    cacheflush(start, start + size, 0);
   #else
     #error FlushICache only tested/supported on Linux and Android
   #endif
 
 #endif
 }
 
 
 const char* CPU::Id() {
   return
@@ skipping 50 matching lines @@
   ASSERT(hardware_ != NULL);
   free(const_cast<char*>(hardware_));
   hardware_ = NULL;
   CpuInfo::Cleanup();
 }
 #endif  // defined(HOST_ARCH_ARM64)
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM64