Rely on CC toolchain resolution on Windows (#1156)

This is a follow up commit to my previous commit [1], which updated the Bazel version from 7.4.1 to 8.0.0 (#1118). It turns out that --noincompatible_enable_cc_toolchain_resolution is now no-op in Bazel 8.0. Thus we have no other choice than fully migrating to the new CC toolchain resolution as planned in #1112. Otherwise 'mozc_tip32.dll' will be built as a 64-bit executable (#1102). This commit consists of two parts: 1. explicitly register CC toolchains in '.bazelrc'. 2. Switch from '--cpu' commandline option to '--platforms' commandline option in '_win_executable_transition'. With above 'mozc_tip32.dll' will be built as a 32-bit executable again. Closes #1102. Closes #1112. [1]: 6dadef1 PiperOrigin-RevId: 713127750
google · Jan 8, 2025 · 4aad25e · 4aad25e
1 parent 5b7a333
commit 4aad25e
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Showing 9 changed files with 37 additions and 21 deletions.
diff --git a/src/.bazelrc b/src/.bazelrc
@@ -56,11 +56,17 @@ test:macos_env   --test_tag_filters=-nomac
 build:windows_env --build_tag_filters=-nowin
 test:windows_env   --test_tag_filters=-nowin
 
-# A temporary workaround to make "mozc_win_build_rule" work.
-# Note that "incompatible_enable_cc_toolchain_resolution" is now enabled by
-# default. See https://github.com/bazelbuild/bazel/issues/7260
-# TODO: Re-enable "incompatible_enable_cc_toolchain_resolution"
-build:windows_env --noincompatible_enable_cc_toolchain_resolution
+# Bazel does not register cc toolchains for Windows by default.
+# We need to explicitly specify them to be compatible with the new behavior
+# introduced by --incompatible_enable_cc_toolchain_resolution
+# https://github.com/google/mozc/issues/1112
+# https://bazel.build/extending/toolchains#registering-building-toolchains
+build:windows_env --extra_toolchains=@@rules_cc++cc_configure_extension+local_config_cc//:cc-toolchain-arm64_windows
+build:windows_env --extra_toolchains=@@rules_cc++cc_configure_extension+local_config_cc//:cc-toolchain-x64_windows
+build:windows_env --extra_toolchains=@@rules_cc++cc_configure_extension+local_config_cc//:cc-toolchain-x64_x86_windows
+test:windows_env  --extra_toolchains=@@rules_cc++cc_configure_extension+local_config_cc//:cc-toolchain-arm64_windows
+test:windows_env  --extra_toolchains=@@rules_cc++cc_configure_extension+local_config_cc//:cc-toolchain-x64_windows
+test:windows_env  --extra_toolchains=@@rules_cc++cc_configure_extension+local_config_cc//:cc-toolchain-x64_x86_windows
 
 # Android specific options
 build:android_env --copt "-DOS_ANDROID"

diff --git a/src/build_defs.bzl b/src/build_defs.bzl
@@ -212,15 +212,15 @@ def _win_executable_transition_impl(
         features = ["static_link_msvcrt"]
     return {
         "//command_line_option:features": features,
-        "//command_line_option:cpu": attr.cpu,
+        "//command_line_option:platforms": [attr.platform],
     }
 
 _win_executable_transition = transition(
     implementation = _win_executable_transition_impl,
     inputs = [],
     outputs = [
         "//command_line_option:features",
-        "//command_line_option:cpu",
+        "//command_line_option:platforms",
     ],
 )
 
@@ -243,11 +243,10 @@ def _mozc_win_build_rule_impl(ctx):
         executable = output,
     )]
 
-# The follwoing CPU values are mentioned in https://bazel.build/configure/windows#build_cpp
 CPU = struct(
-    ARM64 = "arm64_windows",  # aarch64 (64-bit) environment
-    X64 = "x64_windows",  # x86-64 (64-bit) environment
-    X86 = "x64_x86_windows",  # x86 (32-bit) environment
+    ARM64 = "@platforms//cpu:arm64",  # aarch64 (64-bit) environment
+    X64 = "@platforms//cpu:x86_64",  # x86-64 (64-bit) environment
+    X86 = "@platforms//cpu:x86_32",  # x86 (32-bit) environment
 )
 
 _mozc_win_build_rule = rule(
@@ -263,7 +262,7 @@ _mozc_win_build_rule = rule(
             mandatory = True,
         ),
         "static_crt": attr.bool(),
-        "cpu": attr.string(),
+        "platform": attr.label(),
     },
 )
 
@@ -311,6 +310,7 @@ def mozc_win_build_target(
       **kwargs: other arguments passed to mozc_objc_library.
     """
     mandatory_target_compatible_with = [
+        cpu,
         "@platforms//os:windows",
     ]
     for item in mandatory_target_compatible_with:
@@ -322,10 +322,20 @@ def mozc_win_build_target(
         if item not in tags:
             tags.append(item)
 
+    platform_name = "_" + name + "_platform"
+    native.platform(
+        name = platform_name,
+        constraint_values = [
+            cpu,
+            "@platforms//os:windows",
+        ],
+        visibility = ["//visibility:private"],
+    )
+
     _mozc_win_build_rule(
         name = name,
         target = target,
-        cpu = cpu,
+        platform = platform_name,
         static_crt = static_crt,
         target_compatible_with = target_compatible_with,
         tags = tags,

diff --git a/src/gui/tool/BUILD.bazel b/src/gui/tool/BUILD.bazel
@@ -135,7 +135,7 @@ mozc_cc_qt_binary(
 
 mozc_win32_cc_prod_binary(
     name = "mozc_tool_win",
-    cpu = "x64_windows",
+    cpu = "@platforms//cpu:x86_64",
     executable_name_map = {
         "Mozc": "mozc_tool.exe",
         "GoogleJapaneseInput": "GoogleIMEJaTool.exe",

diff --git a/src/renderer/win32/BUILD.bazel b/src/renderer/win32/BUILD.bazel
@@ -48,7 +48,7 @@ package(
 mozc_win32_cc_prod_binary(
     name = "win32_renderer_main",
     srcs = ["win32_renderer_main.cc"],
-    cpu = "x64_windows",
+    cpu = "@platforms//cpu:x86_64",
     executable_name_map = {
         "Mozc": "mozc_renderer.exe",
         "GoogleJapaneseInput": "GoogleIMEJaRenderer.exe",

diff --git a/src/server/BUILD.bazel b/src/server/BUILD.bazel
@@ -59,7 +59,7 @@ mozc_cc_binary(
 
 mozc_win32_cc_prod_binary(
     name = "mozc_server_win",
-    cpu = "x64_windows",
+    cpu = "@platforms//cpu:x86_64",
     executable_name_map = {
         "Mozc": "mozc_server.exe",
         "GoogleJapaneseInput": "GoogleIMEJaConverter.exe",

diff --git a/src/win32/broker/BUILD.bazel b/src/win32/broker/BUILD.bazel
@@ -44,7 +44,7 @@ package(
 mozc_win32_cc_prod_binary(
     name = "mozc_broker_main",
     srcs = ["mozc_broker_main.cc"],
-    cpu = "x64_windows",
+    cpu = "@platforms//cpu:x86_64",
     executable_name_map = {
         "Mozc": "mozc_broker.exe",
         "GoogleJapaneseInput": "GoogleIMEJaBroker.exe",

diff --git a/src/win32/cache_service/BUILD.bazel b/src/win32/cache_service/BUILD.bazel
@@ -45,7 +45,7 @@ package(default_visibility = ["//:__subpackages__"])
 mozc_win32_cc_prod_binary(
     name = "mozc_cache_service",
     srcs = ["mozc_cache_service.cc"],
-    cpu = "x64_windows",
+    cpu = "@platforms//cpu:x86_64",
     executable_name_map = {
         "Mozc": "mozc_cache_service.exe",
         "GoogleJapaneseInput": "GoogleIMEJaCacheService.exe",

diff --git a/src/win32/custom_action/BUILD.bazel b/src/win32/custom_action/BUILD.bazel
@@ -41,7 +41,7 @@ mozc_win32_cc_prod_binary(
         "custom_action.h",
         "resource.h",
     ],
-    cpu = "x64_windows",
+    cpu = "@platforms//cpu:x86_64",
     executable_name_map = {
         "Mozc": "mozc_installer_helper.dll",
         "GoogleJapaneseInput": "GoogleIMEJaInstallerHelper.dll",

diff --git a/src/win32/tip/BUILD.bazel b/src/win32/tip/BUILD.bazel
@@ -68,7 +68,7 @@ mozc_cc_library(
 mozc_win32_cc_prod_binary(
     name = "mozc_tip32",
     srcs = ["mozc_tip_main.cc"],
-    cpu = "x64_x86_windows",
+    cpu = "@platforms//cpu:x86_32",
     executable_name_map = {
         "Mozc": "mozc_tip32.dll",
         "GoogleJapaneseInput": "GoogleIMEJaTIP32.dll",
@@ -87,7 +87,7 @@ mozc_win32_cc_prod_binary(
 mozc_win32_cc_prod_binary(
     name = "mozc_tip64",
     srcs = ["mozc_tip_main.cc"],
-    cpu = "x64_windows",
+    cpu = "@platforms//cpu:x86_64",
     executable_name_map = {
         "Mozc": "mozc_tip64.dll",
         "GoogleJapaneseInput": "GoogleIMEJaTIP64.dll",