""" Downloads clang and configures the crosstool using bazel's autoconf."""

load("@bazel_tools//tools/cpp:cc_configure.bzl", "cc_autoconf_impl")
load(":download_clang.bzl", "download_clang")

_TF_DOWNLOAD_CLANG = "TF_DOWNLOAD_CLANG"
_TF_NEED_CUDA = "TF_NEED_CUDA"

def _cc_clang_autoconf(repo_ctx):
  if repo_ctx.os.environ.get(_TF_DOWNLOAD_CLANG) != "1":
    return
  if repo_ctx.os.environ.get(_TF_NEED_CUDA) == "1":
    # Clang is handled separately for CUDA configs.
    # See cuda_configure.bzl for more details.
    return

  download_clang(repo_ctx, out_folder='extra_tools')
  overriden_tools = {'gcc': 'extra_tools/bin/clang'}
  cc_autoconf_impl(repo_ctx, overriden_tools)

cc_download_clang_toolchain = repository_rule(
    environ = [
        _TF_DOWNLOAD_CLANG,
        _TF_NEED_CUDA,
    ],
    implementation = _cc_clang_autoconf,
)