Fuchsia: Initial check-in.

tools/fuchsia_link.py

Index: tools/fuchsia_link.py
diff --git a/tools/fuchsia_link.py b/tools/fuchsia_link.py
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+++ b/tools/fuchsia_link.py
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+#!/usr/bin/env python
+
+# Copyright (c) 2016 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 Fuchsia NDK executables.
+Usage:
+./fuchsia_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')
+
+
+def CheckDirExists(path, docstring):
+  if not os.path.isdir(path):
+    raise Exception('Could not find %s directory %s'
+          % (docstring, path))
+
+
+def execute(args):
+  process = subprocess.Popen(args)
+  process.wait()
+  return process.returncode
+
+
+def main():
+  if len(sys.argv) < 5:
+    raise Exception(sys.argv[0] + " failed: not enough arguments")
+
+  # gyp puts -shared first in a shared_library link. Remove it.
+  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 ['arm64', 'x64',]:
+    raise Exception(sys.argv[0] +
+        " first argument must be 'arm64', or 'x64'")
+  if link_type not in ['executable', 'library', 'shared_library']:
+    raise Exception(sys.argv[0] +
+      " second argument must be 'executable' or 'library' or 'shared_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
+  # 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 Fuchsia."
+    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 Fuchsia NDK.
+  CheckDirExists(THIRD_PARTY_ROOT, 'third party tools')
+  fuchsia_tools = os.path.join(THIRD_PARTY_ROOT, 'fuchsia_tools')
+  CheckDirExists(fuchsia_tools, 'Fuchsia tools')
+
+  # Set up the directory of the Fuchsia NDK cross-compiler toolchain.
+  toolchain_arch = 'x86_64-elf-5.3.0-Linux-x86_64'
+  if target_arch == 'arm64':
+    toolchain_arch = 'aarch64-elf-5.3.0-Linux-x86_64'
+  fuchsia_toolchain = os.path.join(
+      fuchsia_tools, 'toolchains', toolchain_arch, 'bin')
+  CheckDirExists(fuchsia_toolchain, 'Fuchsia toolchain')
+
+  # Set up the path to the linker executable.
+  fuchsia_linker = os.path.join(fuchsia_toolchain, 'x86_64-elf-g++')
+  if target_arch == 'arm64':
+    fuchsia_linker = os.path.join(fuchsia_toolchain, 'aarch64-elf-c++')
+
+  # 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.
+  fuchsia_gcc = os.path.join(fuchsia_toolchain, 'x86_64-elf-gcc')
+  if target_arch == 'arm64':
+    fuchsia_gcc = os.path.join(fuchsia_toolchain, 'aarch64-elf-gcc')
+  fuchsia_libgcc = subprocess.check_output(
+      [fuchsia_gcc, '-print-libgcc-file-name']).strip()
+
+  # Set up the path to the system root directory, which is where we'll find the
+  # Fuchsia specific system includes and libraries.
+  fuchsia_sysroot = os.path.join(fuchsia_tools, 'sysroot', 'x86_64')
+  if target_arch == 'arm64':
+    fuchsia_sysroot = os.path.join(fuchsia_tools, 'sysroot', 'arm64')
+  CheckDirExists(fuchsia_sysroot, 'Fuchsia sysroot')
+  fuchsia_lib = os.path.join(fuchsia_sysroot, 'usr', 'lib')
+  crtn_fuchsia = os.path.join(fuchsia_lib, 'crtn.o')
+
+  if link_target == 'target':
+    # Add and remove libraries as listed in configurations_fuchsia.gypi
+    libs_to_rm = ['-lrt', '-lpthread', '-ldl']
+    libs_to_add = [fuchsia_libgcc, '-lc',]
+
+    # Add crtn_fuchsia to end if we are linking an executable.
+    if link_type == 'executable':
+      libs_to_add.extend([crtn_fuchsia])
+
+    link_args = [i for i in link_args if i not in libs_to_rm]
+    link_args.extend(libs_to_add)
+
+    link_args.insert(0, fuchsia_linker)
+  else:
+    link_args.extend(['-ldl', '-lrt'])
+    link_args.insert(0, 'g++')
+
+  print ' '.join(link_args)
+  sys.exit(execute(link_args))
+
+if __name__ == '__main__':
+  main()