# Reuse rules_cc's installed SDK setup with an explicitly declared LLVM repo.
# Only the V8 repository has native_llvm; ordinary local_config_cc keeps its
# installed compiler and input files. Track the fetched LLVM tools and resources
# as action inputs so changes to the pin invalidate cached compilation and links.
diff --git a/cc/private/toolchain/windows_cc_configure.bzl b/cc/private/toolchain/windows_cc_configure.bzl
--- a/cc/private/toolchain/windows_cc_configure.bzl
+++ b/cc/private/toolchain/windows_cc_configure.bzl
@@ -539,6 +539,12 @@
         The path to the LLVM installation, or None if not found.
     """

+    # Codex's opt-in V8 toolchain supplies a Bazel-fetched compiler.
+    # Ordinary cc_autoconf repositories have no such attribute.
+    llvm_label = getattr(repository_ctx.attr, "native_llvm", None)
+    if llvm_label:
+        return str(repository_ctx.path(llvm_label).dirname).replace("/", "\\")
+
     # 1. Check if BAZEL_LLVM is already set by user.
     bazel_llvm = _get_path_env_var(repository_ctx, "BAZEL_LLVM")
     if bazel_llvm:
@@ -602,7 +608,7 @@

 def _use_clang_cl(repository_ctx):
     """Returns True if USE_CLANG_CL is set to 1."""
-    return _get_env_var(repository_ctx, "USE_CLANG_CL", default = "0") == "1"
+    return getattr(repository_ctx.attr, "native_llvm", None) != None or _get_env_var(repository_ctx, "USE_CLANG_CL", default = "0") == "1"

 def _find_missing_llvm_tools(repository_ctx, llvm_path):
     """Check if any required tool is missing under given LLVM path."""
@@ -716,6 +722,7 @@

         build_tools["CL"] = find_llvm_tool(repository_ctx, llvm_path, "clang-cl.exe")
         build_tools["ML"] = find_msvc_tool(repository_ctx, vc_path, "ml64.exe", "x64")
+        build_tools["DUMPBIN"] = find_msvc_tool(repository_ctx, vc_path, "dumpbin.exe", target_arch)
         build_tools["LINK"] = find_llvm_tool(repository_ctx, llvm_path, "lld-link.exe")
         if not build_tools["LINK"]:
             build_tools["LINK"] = find_msvc_tool(repository_ctx, vc_path, "link.exe", "x64")
@@ -923,6 +930,12 @@
     )

     template_vars = dict()
+    native_llvm = getattr(repository_ctx.attr, "native_llvm", None)
+    for group in ["compiler_files", "linker_files", "archiver_files", "all_files"]:
+        files = [str(native_llvm.same_package_label(group))] if native_llvm else []
+        if native_llvm and group == "all_files":
+            files.append(":msvc_compiler_files")
+        template_vars["%{native_llvm_" + group + "}"] = repr(files)
     msvc_vars_x64 = _get_msvc_vars(repository_ctx, paths, "x64")
     template_vars.update(msvc_vars_x64)
     template_vars.update(_get_clang_cl_vars(repository_ctx, paths, msvc_vars_x64, "x64"))
diff --git a/cc/private/toolchain/BUILD.windows.tpl b/cc/private/toolchain/BUILD.windows.tpl
--- a/cc/private/toolchain/BUILD.windows.tpl
+++ b/cc/private/toolchain/BUILD.windows.tpl
@@ -67,7 +67,22 @@
         "%{msvc_deps_scanner_wrapper_path_x64}",
         "%{msvc_deps_scanner_wrapper_path_arm}",
         "%{msvc_deps_scanner_wrapper_path_arm64}",
-    ]
+    ] + %{native_llvm_compiler_files}
+)
+
+filegroup(
+    name = "msvc_all_files",
+    srcs = %{native_llvm_all_files},
+)
+
+filegroup(
+    name = "msvc_linker_files",
+    srcs = %{native_llvm_linker_files},
+)
+
+filegroup(
+    name = "msvc_archiver_files",
+    srcs = %{native_llvm_archiver_files},
 )

 # Hardcoded toolchain, legacy behaviour.
@@ -301,12 +316,12 @@
     name = "cc-compiler-x64_windows",
     toolchain_identifier = "msvc_x64",
     toolchain_config = ":msvc_x64",
-    all_files = ":empty",
-    ar_files = ":empty",
+    all_files = ":msvc_all_files",
+    ar_files = ":msvc_archiver_files",
     as_files = ":msvc_compiler_files",
     compiler_files = ":msvc_compiler_files",
     dwp_files = ":empty",
-    linker_files = ":empty",
+    linker_files = ":msvc_linker_files",
     objcopy_files = ":empty",
     strip_files = ":empty",
     supports_param_files = 1,
@@ -526,12 +541,12 @@
     name = "cc-compiler-arm64_windows",
     toolchain_identifier = "msvc_arm64",
     toolchain_config = ":msvc_arm64",
-    all_files = ":empty",
-    ar_files = ":empty",
+    all_files = ":msvc_all_files",
+    ar_files = ":msvc_archiver_files",
     as_files = ":msvc_compiler_files",
     compiler_files = ":msvc_compiler_files",
     dwp_files = ":empty",
-    linker_files = ":empty",
+    linker_files = ":msvc_linker_files",
     objcopy_files = ":empty",
     strip_files = ":empty",
     supports_param_files = 1,