Attempt 1 at windows build.

.github/workflows/windows_amd64_build.yaml

@@ -0,0 +1,120 @@
+# Based on version from @dfalbel in https://github.com/r-xla/pjrt-builds
+on:
+  workflow_dispatch:
+
+name: Build PJRT
+
+permissions:
+  contents: write
+
+jobs:
+  build:
+    name: "Build Windows (amd64) Plugin"
+
+    env:
+      GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+    defaults:
+      run:
+        shell:
+          bash
+
+          # artifact_name: pjrt_cpu.dll
+          # target: pjrt_c_api_cpu_plugin.so
+          # setup: |
+    steps:
+      - uses: actions/checkout@v4
+
+      - run: |
+          choco install llvm -y
+          # Remove MSVC from PATH to force clang usage
+          echo "PATH=$(echo $PATH | tr ':' '\n' | grep -v 'Microsoft Visual Studio' | grep -v 'VC/Tools/MSVC' | tr '\n' ':')" >> $GITHUB_ENV
+
+      - run: |
+          git clone https://github.com/openxla/xla
+          cd xla
+          HASH=$(cat ../XLA_COMMIT_HASH.txt)
+          echo "Checking out XLA at commit: $HASH"
+          git checkout $HASH
+
+      - run: |
+          BUILDER_VERSION="$(cat BUILDER_VERSION.txt)"
+          MAJOR=$(grep -E '#define PJRT_API_MAJOR' "${PJRT_C_API_HEADER}" | awk '{print $3}')
+          MINOR=$(grep -E '#define PJRT_API_MINOR' "${PJRT_C_API_HEADER}" | awk '{print $3}')
+          echo "Building PJRT CPU plugin for version ${MAJOR}.${MINOR} (to be used in go-xla as v${MAJOR}.${MINOR}.${BUILDER_VERSION})"
+          echo "RELEASE=v${MAJOR}.${MINOR}.${BUILDER_VERSION}" >> $GITHUB_ENV
+
+      - run: |
+          cd xla
+          python configure.py --backend=cpu --os=windows --host_compiler=clang --clang_path=C:/PROGRA~1/LLVM/bin/clang.exe
+          cat xla_configure.bazelrc
+
+      - name: Fix Windows paths in bazelrc
+        run: |
+          cd xla
+          # Fix Windows paths for Bazel compatibility
+          # Replace "Program Files" with short name (handles both / and \ separators)
+          sed -i 's|Program Files|PROGRA~1|g' xla_configure.bazelrc
+          # Convert all backslashes to forward slashes
+          sed -i 's|\\|/|g' xla_configure.bazelrc
+          cat xla_configure.bazelrc
+
+          echo "Applying dllexport patch ---------------"
+          git apply ../patches/windows/export.patch
+
+      - run: |
+          cd xla
+          printf "\nStarting XLA bazel build:\n"
+          bazel build \
+            --config=clang_local \
+            --action_env=CC=C:/PROGRA~1/LLVM/bin/clang.exe \
+            --action_env=CXX=C:/PROGRA~1/LLVM/bin/clang++.exe \
+            --linkopt="--ld-path=C:/PROGRA~1/LLVM/bin/ld.lld.exe" \
+            --repo_env=BAZEL_COMPILER=C:/PROGRA~1/LLVM/bin/clang.exe \
+            --repo_env=USE_CLANG_CL=1 \
+            --copt=-march=native \
+            --define xnn_enable_arm_fp16_scalar=false \
+            --define xnn_enable_arm_fp16_vector=false \
+            --define xnn_enable_arm_bf16=false \
+            --define xnn_enable_arm_dotprod=false \
+            --define xnn_enable_arm_i8mm=false \
+            --define xnn_enable_arm_sme=false \
+            --define xnn_enable_arm_sme2=false \
+            --define xnn_enable_riscv_vector=false \
+            --define xnn_enable_riscv_fp16_vector=false \
+            --define xnn_enable_avxvnni=false \
+            --define xnn_enable_avxvnniint8=false \
+            --define xnn_enable_avx256skx=false \
+            --define xnn_enable_avx256vnni=false \
+            --define xnn_enable_avx256vnnigfni=false \
+            --define xnn_enable_avx512f=false \
+            --define xnn_enable_avx512skx=false \
+            --define xnn_enable_avx512vbmi=false \
+            --define xnn_enable_avx512vnni=false \
+            --define xnn_enable_avx512vnnigfni=false \
+            --define xnn_enable_avx512amx=false \
+            --define xnn_enable_avx512fp16=false \
+            --define xnn_enable_avx512bf16=false \
+            --define xnn_enable_hvx=false \
+            //xla/pjrt/c:pjrt_c_api_cpu_plugin.so
+
+      - name: "Package the binary"
+        run: |
+          # Create the tarball.
+          PJRT_C_API_HEADER="./xla/xla/pjrt/c/pjrt_c_api.h"
+          ZIP_NAME="pjrt_cpu_windows_amd64.zip"
+          BINARY_DIR="xla/bazel-bin/xla/pjrt/c"
+          BINARY_NAME="pjrt_c_api_cpu_plugin.so"
+          TARGET_NAME="pjrt_c_api_cpu_plugin.dll"
+          mv "xla/bazel-bin/xla/pjrt/c/${BINARY_NAME}" "${TARGET_NAME}"
+          7z a "$ZIP_NAME" "${TARGET_NAME}"
+          echo "ZIP_NAME=${ZIP_NAME}" >> $GITHUB_ENV
+
+      - name: Upload release asset
+        uses: softprops/action-gh-release@v2
+        with:
+          tag_name: ${{ env.RELEASE }}
+          files: ${{ env.ZIP_NAME }}
+          name: CPU
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

internal/patches/windows/export.patch

@@ -0,0 +1,10 @@
+diff --git a/xla/pjrt/c/pjrt_c_api_cpu.cc b/xla/pjrt/c/pjrt_c_api_cpu.cc
+index 90e391f8..d5d51dd4 100644
+--- a/xla/pjrt/c/pjrt_c_api_cpu.cc
++++ b/xla/pjrt/c/pjrt_c_api_cpu.cc
+@@ -17,4 +17,5 @@ limitations under the License.
+ #include "xla/pjrt/c/pjrt_c_api.h"
+ #include "xla/pjrt/c/pjrt_c_api_cpu_internal.h"
+
++extern "C" __declspec(dllexport)
+ const PJRT_Api* GetPjrtApi() { return pjrt::cpu_plugin::GetCpuPjrtApi(); }