Fix various alignments to make ARM precompilation work on Windows.

runtime/vm/os_win.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"
 #if defined(TARGET_OS_WINDOWS)
 
 #include "vm/os.h"
 
 #include <malloc.h>   // NOLINT
@@ skipping 171 matching lines @@
 }
 
 
 int64_t OS::GetCurrentThreadCPUMicros() {
   // TODO(johnmccutchan): Implement. See base/time_win.cc for details.
   return -1;
 }
 
 
 intptr_t OS::ActivationFrameAlignment() {
-#ifdef _WIN64
+#if defined(TARGET_ARCH_ARM64)
+  return 16;
+#elif defined(TARGET_ARCH_ARM) || defined(TARGET_ARCH_MIPS)
+  return 8;
+#elif defined(_WIN64)
   // Windows 64-bit ABI requires the stack to be 16-byte aligned.
   return 16;
 #else
   // No requirements on Win32.
   return 1;
 #endif
 }
 
 
 intptr_t OS::PreferredCodeAlignment() {
   ASSERT(32 <= OS::kMaxPreferredCodeAlignment);
+#if defined(TARGET_ARCH_IA32) || defined(TARGET_ARCH_X64) ||                   \
+    defined(TARGET_ARCH_ARM64) || defined(TARGET_ARCH_DBC)
   return 32;
+#elif defined(TARGET_ARCH_ARM) || defined(TARGET_ARCH_MIPS)
+  return 16;
+#else
+#error Unsupported architecture.
+#endif
 }
 
 
 bool OS::AllowStackFrameIteratorFromAnotherThread() {
   return true;
 }
 
 
 int OS::NumberOfAvailableProcessors() {
   SYSTEM_INFO info;
@@ skipping 219 matching lines @@
   // TODO(zra): Remove once VM shuts down cleanly.
   private_flag_windows_run_tls_destructors = false;
   // On Windows we use ExitProcess so that threads can't clobber the exit_code.
   // See: https://code.google.com/p/nativeclient/issues/detail?id=2870
   ::ExitProcess(code);
 }
 
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_WINDOWS)