Build mozc_tip64.dll for ARM64 with GYP

As a preparation to build Mozc for ARM64 in Windows (google#1130), this commit
demonstrates that it is technically possible for us to build
'mozc_tip64.dll' as an ARM64 DLL with GYP even though GYP itself does
not officially support it.

With this commit you need to install the following additional Visual
Studio components even when you do not build Mozc for ARM64 Windows.

  * Microsoft.VisualStudio.Component.VC.Redist.14.Latest
  * Microsoft.VisualStudio.Component.VC.ATL
  * Microsoft.VisualStudio.Component.VC.Tools.x86.x64
  * Microsoft.VisualStudio.Component.VC.ATL.ARM64
  * Microsoft.VisualStudio.Component.VC.Tools.ARM64

Note that 'mozc_tip64.dll' for ARM64 will be built only when explicitly
specified in 'build_mozc.py build'. There must be no change in the final
artifacts when just building the installer package.

Note also that we still need to build ARM64X DLL to actually support
ARM64 Windows environment.

docs/build_mozc_in_windows.md

@@ -38,6 +38,12 @@ Building Mozc on Windows requires the following software.
 
   * [Visual Studio 2022 Community Edition](https://visualstudio.microsoft.com/downloads/#visual-studio-community-2022)
     * [Build Tools for Visual Studio 2022](https://visualstudio.microsoft.com/downloads/#build-tools-for-visual-studio-2022) should also work
+    * Make sure that the following components are installed.
+      * `Microsoft.VisualStudio.Component.VC.Redist.14.Latest`
+      * `Microsoft.VisualStudio.Component.VC.ATL`
+      * `Microsoft.VisualStudio.Component.VC.Tools.x86.x64`
+      * `Microsoft.VisualStudio.Component.VC.ATL.ARM64`
+      * `Microsoft.VisualStudio.Component.VC.Tools.ARM64`
   * Python 3.9 or later with the following pip modules.
     * `six`
     * `requests`

src/build_mozc.py

@@ -43,6 +43,7 @@
 import optparse
 import os
 import pathlib
+import platform
 import re
 import subprocess
 import sys
@@ -370,18 +371,40 @@ def WriteEnvironmentFile(path, env):
     f.write(nul.join(entries).encode('utf-8'))
 
 
-def UpdateEnvironmentFilesForWindows(out_dir):
+def UpdateEnvironmentFilesForWindows(out_dir, vcvarsall_path):
   """Add required environment variables for Ninja build."""
   python_path_root = MOZC_ROOT
   python_path = os.path.abspath(python_path_root)
   original_python_paths = os.environ.get('PYTHONPATH', '')
   if original_python_paths:
     python_path = os.pathsep.join([original_python_paths, python_path])
+
   for d in os.listdir(out_dir):
     abs_dir = os.path.abspath(os.path.join(out_dir, d))
+    # Tweak generated build rules for ARM64
+    if d.endswith('arm64'):
+      build_ninja = os.path.join(abs_dir, 'build.ninja')
+      with open(build_ninja, 'r', encoding='utf-8') as f:
+        lines = f.readlines()
+        for i in range(0, 2):
+          lines[i] = lines[i].replace('x64\\cl.exe', 'arm64\\cl.exe')
+          lines[i] = lines[i].replace('x86\\cl.exe', 'arm64\\cl.exe')
+      with open(build_ninja, 'w', encoding='utf-8') as f:
+        f.writelines(lines)
+
     for arch in ['x86', 'x64']:
       env_file = os.path.join(abs_dir, f'environment.{arch}')
       env = ReadEnvironmentFile(env_file)
+      # Tweak for ARM64
+      if d.endswith('arm64'):
+        vs_arch = platform.uname().machine
+        if vs_arch != 'arm64':
+          vs_arch = vs_arch + '_arm64'
+        vs_env = get_vs_env_vars(vs_arch, vcvarsall_path_hint=vcvarsall_path)
+        env['INCLUDE'] = vs_env['INCLUDE']
+        env['LIB'] = vs_env['LIB']
+        env['LIBPATH'] = vs_env['LIBPATH']
+        env['PATH'] = vs_env['PATH']
       env['PYTHONPATH'] = python_path
       env['VSLANG'] = '1033' # == MAKELANGID(LANG_ENGLISH, SUBLANG_ENGLISH_US)
       WriteEnvironmentFile(env_file, env)
@@ -561,7 +584,7 @@ def GypMain(options, unused_args):
   # For internal Ninja build on Windows, set up environment files
   if IsWindows():
     out_dir = os.path.join(MOZC_ROOT, 'out_win')
-    UpdateEnvironmentFilesForWindows(out_dir)
+    UpdateEnvironmentFilesForWindows(out_dir, options.vcvarsall_path)
 
   if IsWindows() and qt_dir and qt_ver:
     # When Windows build is configured to use DLL version of Qt, copy Qt's DLLs

src/build_tools/protoc_wrapper.py

@@ -85,6 +85,12 @@ def main():
   protoc_path = opts.protoc_command
   if opts.protoc_dir:
     protoc_path = os.path.join(os.path.abspath(opts.protoc_dir), protoc_path)
+    # A hack for ARM64 build with GYP on Windows.
+    #   https://github.com/google/mozc/issues/1130
+    # ARM64 version of protoc.exe does not work on x64 machine, so use x64
+    # version with an assumption that it's already built.
+    if os.name == 'nt' and protoc_path.endswith('_arm64\\protoc.exe'):
+      protoc_path = protoc_path.replace('_arm64\\protoc', '_x64\\protoc')
 
   # The path of proto file should be transformed as a relative path from
   # the project root so that correct relative paths should be embedded into

src/gyp/common_win.gypi

@@ -167,6 +167,27 @@
           },
         },
       },
+      'arm64_Base': {
+        'abstract': 1,
+        'msvs_configuration_attributes': {
+          'OutputDirectory': '<(build_base)/$(ConfigurationName)_arm64',
+          'IntermediateDirectory': '<(build_base)/$(ConfigurationName)_arm64/obj/$(ProjectName)',
+        },
+        'msvs_target_platform': 'arm64',
+        'msvs_settings': {
+          'VCCLCompilerTool': {
+            'AdditionalOptions': [
+              '/bigobj',
+            ],
+          },
+          'VCLinkerTool': {
+            'ImageHasSafeExceptionHandlers': 'false',
+            'AdditionalOptions': [
+              '/MACHINE:ARM64',
+            ],
+          },
+        },
+      },
       'Win_Static_Debug_CRT_Base': {
         'abstract': 1,
         'msvs_settings': {
@@ -276,6 +297,12 @@
       'Release_x64': {
         'inherit_from': ['x64_Base', 'Release_Base', 'Win_Static_Release_CRT_Base'],
       },
+      'Debug_arm64': {
+        'inherit_from': ['arm64_Base', 'Debug_Base', 'Win_Static_Debug_CRT_Base'],
+      },
+      'Release_arm64': {
+        'inherit_from': ['arm64_Base', 'Release_Base', 'Win_Static_Release_CRT_Base'],
+      },
     },
     'default_configuration': 'Debug',
     'defines': [