Run Bazel CI on Windows

PiperOrigin-RevId: 655960875

.bazelrc

@@ -1,13 +1,17 @@
 # Set up to use C++20.
-build --cxxopt='-std=c++20'
+build --cxxopt=-std=c++20
+
+# Use the builtin crc32 for fast integer hashing.
 build --copt=-mcrc32
 
 # Enable Bzlmod for every Bazel command
 common --enable_bzlmod
 
-# Use the builtin crc32 for fast integer hashing.
-build --copt=-mcrc32
-
 # To create this file, please run:
 #  bazel run @com_google_fuzztest//bazel:setup_configs > fuzztest.bazelrc
 try-import %workspace%/fuzztest.bazelrc
+
+build:win_clang --extra_toolchains=@local_config_cc//:cc-toolchain-x64_windows-clang-cl
+build:win_clang --extra_execution_platforms=//:x64_windows-clang-cl
+build:win_clang --compiler=clang-cl
+build:win_clang --cxxopt=/std:c++20

.github/workflows/bazel-test.yaml

@@ -7,12 +7,17 @@ jobs:
   bazel_test:
     strategy:
       matrix:
-        os: [ubuntu-latest, macos-latest]
+        os: [ubuntu-latest, macos-latest, windows-latest]
 
     runs-on: ${{ matrix.os }}
 
     steps:
     - uses: actions/checkout@v4
 
-    - name: Test
+    - name: Test (Linux and Mac config)
+      if: runner.os != 'Windows'
       run: bazel test --test_output=errors //...
+
+    - name: Test (Windows config)
+      if: runner.os == 'Windows'
+      run: bazel test --config=win_clang --test_output=errors //...

BUILD

@@ -26,3 +26,14 @@ alias(
     actual = "@com_google_googletest//:gtest",
     visibility = ["//:__subpackages__"],
 )
+
+# For building with clang-cl.
+# https://bazel.build/configure/windows#clang
+platform(
+    name = "x64_windows-clang-cl",
+    constraint_values = [
+        "@platforms//cpu:x86_64",
+        "@platforms//os:windows",
+        "@bazel_tools//tools/cpp:clang-cl",
+    ],
+)