Adds support for building arm64 Android.

tools/android_link.py

 #!/usr/bin/env python
 
 # Copyright (c) 2012 The Dart Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """
 This script performs the final link step for Android NDK executables.
 Usage:
-./android_link {arm,ia32} {executable,library,shared_library} {host,target}
-               [linker args]
+./android_link {arm,arm64,ia32} {executable,library,shared_library}
+               {host,target} [linker args]
 """
 
 import os
 import subprocess
 import sys
 
 # Figure out where we are.
 SCRIPT_DIR = os.path.dirname(sys.argv[0])
 DART_ROOT = os.path.realpath(os.path.join(SCRIPT_DIR, '..'))
 THIRD_PARTY_ROOT = os.path.join(DART_ROOT, 'third_party')
@@ skipping 19 matching lines @@
   if sys.argv[1] == '-shared':
     sys.argv.remove('-shared')
 
   # Grab the command line arguments.
   target_arch = sys.argv[1]
   link_type = sys.argv[2]
   link_target = sys.argv[3]
   link_args = sys.argv[4:]
 
   # Check arguments.
-  if target_arch not in ['arm', 'ia32']:
-    raise Exception(sys.argv[0] + " first argument must be 'arm' or 'ia32'")
+  if target_arch not in ['arm', 'arm64', 'ia32']:
+    raise Exception(sys.argv[0] +
+        " first argument must be 'arm', 'arm64', or 'ia32'")
   if link_type not in ['executable', 'library', 'shared_library']:
     raise Exception(sys.argv[0] +
                     " second argument must be 'executable' or 'library'")
   if link_target not in ['host', 'target']:
     raise Exception(sys.argv[0] + " third argument must be 'host' or 'target'")
 
   # TODO(zra): Figure out how to link a shared library with the NDK
   # cross-compilers. For now, we disable it by generating empty files
   # for the results. We disable it here to avoid inspecting the OS type in
   # the gyp files.
   if link_type == 'shared_library':
     print "NOT linking shared library for Android."
     o_index = link_args.index('-o')
     output = os.path.join(DART_ROOT, link_args[o_index + 1])
     open(output, 'a').close()
     sys.exit(0)
 
   # Set up path to the Android NDK.
   CheckDirExists(THIRD_PARTY_ROOT, 'third party tools')
   android_tools = os.path.join(THIRD_PARTY_ROOT, 'android_tools')
   CheckDirExists(android_tools, 'Android tools')
   android_ndk_root = os.path.join(android_tools, 'ndk')
   CheckDirExists(android_ndk_root, 'Android NDK')
 
   # Set up the directory of the Android NDK cross-compiler toolchain.
   toolchain_arch = 'arm-linux-androideabi-4.6'
+  if target_arch == 'arm64':
+    toolchain_arch = 'aarch64-linux-android-4.9'
   if target_arch == 'ia32':
     toolchain_arch = 'x86-4.6'
   toolchain_dir = 'linux-x86_64'
   android_toolchain = os.path.join(android_ndk_root,
       'toolchains', toolchain_arch,
       'prebuilt', toolchain_dir, 'bin')
   CheckDirExists(android_toolchain, 'Android toolchain')
 
   # Set up the path to the linker executable.
   android_linker = os.path.join(android_toolchain, 'arm-linux-androideabi-g++')
+  if target_arch == 'arm64':
+    android_linker = os.path.join(
+        android_toolchain, 'aarch64-linux-android-c++')
   if target_arch == 'ia32':
     android_linker = os.path.join(android_toolchain, 'i686-linux-android-g++')
 
   # Grab the path to libgcc.a, which we must explicitly add to the link,
   # by invoking the cross-compiler with the -print-libgcc-file-name flag.
   android_gcc = os.path.join(android_toolchain, 'arm-linux-androideabi-gcc')
+  if target_arch == 'arm64':
+    android_gcc = os.path.join(android_toolchain, 'aarch64-linux-android-gcc')
   if target_arch == 'ia32':
     android_gcc = os.path.join(android_toolchain, 'i686-linux-android-gcc')
   android_libgcc = subprocess.check_output(
       [android_gcc, '-print-libgcc-file-name']).strip()
 
   # Set up the path to the system root directory, which is where we'll find the
   # Android specific system includes and libraries.
   android_ndk_sysroot = os.path.join(android_ndk_root,
       'platforms', 'android-14', 'arch-arm')
+  if target_arch == 'arm64':
+    android_ndk_sysroot = os.path.join(android_ndk_root,
+      'platforms', 'android-L', 'arch-arm64')
   if target_arch == 'ia32':
     android_ndk_sysroot = os.path.join(android_ndk_root,
         'platforms', 'android-14', 'arch-x86')
   CheckDirExists(android_ndk_sysroot, 'Android sysroot')
   android_ndk_lib = os.path.join(android_ndk_sysroot,'usr','lib')
   android_ndk_include = os.path.join(android_ndk_sysroot, 'usr', 'include')
   crtend_android = os.path.join(android_ndk_lib, 'crtend_android.o')
 
   if link_target == 'target':
     # Add and remove libraries as listed in configurations_android.gypi
@@ skipping 11 matching lines @@
 
     link_args.insert(0, android_linker)
   else:
     link_args.extend(['-ldl', '-lrt'])
     link_args.insert(0, 'g++')
 
   sys.exit(execute(link_args))
 
 if __name__ == '__main__':
   main()