Allow to download clang and use clang for CPU builds.

Previously we only allowed to download clang when doing GPU builds.

The added skylark files use bazel's autoconf scripts, which were only added in
0.10.0. To provide nice error message for older versions of bazel
(i.e. 'version is less than 0.10' vs 'can't load @bazel_tools/cpp/...'), we
move the bazel version check into WORKSPACE file from workspace.bzl.

PiperOrigin-RevId: 190050798

1 files changed, 14 insertions, 12 deletions

diff --git a/configure.py b/configure.py
index 7d61c2e5e3..ea732c64e2 100644
--- a/configure.py
+++ b/configure.py
@@ -524,7 +524,7 @@ def set_tf_cuda_clang(environ_cp):
 
 def set_tf_download_clang(environ_cp):
   """Set TF_DOWNLOAD_CLANG action_env."""
-  question = 'Do you want to download a fresh release of clang? (Experimental)'
+  question = 'Do you wish to download a fresh release of clang? (Experimental)'
   yes_reply = 'Clang will be downloaded and used to compile tensorflow.'
   no_reply = 'Clang will not be downloaded.'
   set_action_env_var(
@@ -1380,7 +1380,7 @@ def main():
   # environment variables.
   environ_cp = dict(os.environ)
 
-  check_bazel_version('0.5.4')
+  check_bazel_version('0.10.0')
 
   reset_tf_configure_bazelrc(args.workspace)
   cleanup_makefile()
@@ -1397,6 +1397,9 @@ def main():
     environ_cp['TF_NEED_OPENCL'] = '0'
     environ_cp['TF_CUDA_CLANG'] = '0'
     environ_cp['TF_NEED_TENSORRT'] = '0'
+    # TODO(ibiryukov): Investigate using clang as a cpu or cuda compiler on
+    # Windows.
+    environ_cp['TF_DOWNLOAD_CLANG'] = '0'
 
   if is_macos():
     environ_cp['TF_NEED_JEMALLOC'] = '0'
@@ -1444,16 +1447,8 @@ def main():
 
     set_tf_cuda_clang(environ_cp)
     if environ_cp.get('TF_CUDA_CLANG') == '1':
-      if not is_windows():
-        # Ask if we want to download clang release while building.
-        set_tf_download_clang(environ_cp)
-      else:
-        # We use bazel's generated crosstool on Windows and there is no
-        # way to provide downloaded toolchain for that yet.
-        # TODO(ibiryukov): Investigate using clang as a cuda compiler on
-        # Windows.
-        environ_cp['TF_DOWNLOAD_CLANG'] = '0'
-
+      # Ask whether we should download the clang toolchain.
+      set_tf_download_clang(environ_cp)
       if environ_cp.get('TF_DOWNLOAD_CLANG') != '1':
         # Set up which clang we should use as the cuda / host compiler.
         set_clang_cuda_compiler_path(environ_cp)
@@ -1463,6 +1458,13 @@ def main():
       if not is_windows():
         set_gcc_host_compiler_path(environ_cp)
     set_other_cuda_vars(environ_cp)
+  else:
+    # CUDA not required. Ask whether we should download the clang toolchain and
+    # use it for the CPU build.
+    set_tf_download_clang(environ_cp)
+    if environ_cp.get('TF_DOWNLOAD_CLANG') == '1':
+      write_to_bazelrc('build --config=download_clang')
+      write_to_bazelrc('test --config=download_clang')
 
   set_build_var(environ_cp, 'TF_NEED_MPI', 'MPI', 'with_mpi_support', False)
   if environ_cp.get('TF_NEED_MPI') == '1':