build: enable update scripts to work with out-of-tree builds (#1553)

Before this patch, the update_shape_lib.sh and update_torch_ods.sh
scripts only worked on in-tree builds, which implied that the
RollPyTorch action was forced to run the longer-running in-tree build.
As a result of this patch, we should be able to run through the basic
checks in the RollPyTorch action faster, while running the full suite of
tests off the critical path.

The key change in this patch is that the update scripts now look for the
directory that is most recently modified between in-tree or out-of-tree
build directories.  The change also correctly handles the case when only
one of the two directories exists.

build_tools/update_shape_lib.sh

@@ -14,7 +14,21 @@ set -euo pipefail
 src_dir="$(realpath "$(dirname "$0")"/..)"
 build_dir="$(realpath "${TORCH_MLIR_BUILD_DIR:-$src_dir/build}")"
 torch_transforms_cpp_dir="${src_dir}/lib/Dialect/Torch/Transforms"
-python_packages_dir="${build_dir}/tools/torch-mlir/python_packages"
+
+in_tree_pkg_dir="${build_dir}/tools/torch-mlir/python_packages"
+out_of_tree_pkg_dir="${build_dir}/python_packages"
+
+if [[ ! -d "${in_tree_pkg_dir}" && ! -d "${out_of_tree_pkg_dir}" ]]; then
+  echo "Couldn't find in-tree or out-of-tree build, exiting."
+  exit 1
+fi
+
+# The `-nt` check works even if one of the two directories is missing.
+if [[ "${in_tree_pkg_dir}" -nt "${out_of_tree_pkg_dir}" ]]; then
+  python_packages_dir="${in_tree_pkg_dir}"
+else
+  python_packages_dir="${out_of_tree_pkg_dir}"
+fi
 
 TORCH_MLIR_EXT_PYTHONPATH="${TORCH_MLIR_EXT_PYTHONPATH:-""}"
 pypath="${python_packages_dir}/torch_mlir"

build_tools/update_torch_ods.sh

@@ -14,7 +14,21 @@ set -euo pipefail
 src_dir="$(realpath "$(dirname "$0")"/..)"
 build_dir="$(realpath "${TORCH_MLIR_BUILD_DIR:-$src_dir/build}")"
 torch_ir_include_dir="${src_dir}/include/torch-mlir/Dialect/Torch/IR"
-python_packages_dir="${build_dir}/tools/torch-mlir/python_packages"
+
+in_tree_pkg_dir="${build_dir}/tools/torch-mlir/python_packages"
+out_of_tree_pkg_dir="${build_dir}/python_packages"
+
+if [[ ! -d "${in_tree_pkg_dir}" && ! -d "${out_of_tree_pkg_dir}" ]]; then
+  echo "Couldn't find in-tree or out-of-tree build, exiting."
+  exit 1
+fi
+
+# The `-nt` check works even if one of the two directories is missing.
+if [[ "${in_tree_pkg_dir}" -nt "${out_of_tree_pkg_dir}" ]]; then
+  python_packages_dir="${in_tree_pkg_dir}"
+else
+  python_packages_dir="${out_of_tree_pkg_dir}"
+fi
 
 TORCH_MLIR_EXT_PYTHONPATH="${TORCH_MLIR_EXT_PYTHONPATH:-""}"
 pypath="${python_packages_dir}/torch_mlir"