Simplify setting up LLVM as bazel external repo

Only require one intermediate repository instead of two.
Fewer parameters in llvm_config.
Remove bazel_skylib dependency.

Reviewed By: goncharov

Differential Revision: https://reviews.llvm.org/D107714

Author: chsigg

utils/bazel/WORKSPACE

@@ -16,14 +16,16 @@ http_archive(
     ],
 )
 
-load(":configure.bzl", "llvm_configure")
-
-llvm_configure(
-    name = "llvm-project",
-    overlay_path = "llvm-project-overlay",
-    src_path = "../..",
+new_local_repository(
+    name = "llvm-archive",
+    path = "../../",
+    build_file_content = "# empty",
 )
 
+load("@llvm-archive//utils/bazel:configure.bzl", "llvm_configure")
+
+llvm_configure(name = "llvm-project")
+
 load(":terminfo.bzl", "llvm_terminfo_from_env")
 
 maybe(

utils/bazel/configure.bzl

@@ -5,7 +5,6 @@
 """Helper macros to configure the LLVM overlay project."""
 
 load("@bazel_tools//tools/build_defs/repo:utils.bzl", "maybe")
-load("@bazel_skylib//lib:paths.bzl", "paths")
 load(":zlib.bzl", "llvm_zlib_disable", "llvm_zlib_system")
 load(":terminfo.bzl", "llvm_terminfo_disable", "llvm_terminfo_system")
 
@@ -33,23 +32,11 @@ DEFAULT_TARGETS = [
 ]
 
 def _overlay_directories(repository_ctx):
-    src_workspace_path = str(repository_ctx.path(
-        repository_ctx.attr.src_workspace,
-    ).dirname)
-
-    src_path = paths.join(src_workspace_path, repository_ctx.attr.src_path)
-
-    overlay_workspace_path = str(repository_ctx.path(
-        repository_ctx.attr.overlay_workspace,
-    ).dirname)
-    overlay_path = paths.join(
-        overlay_workspace_path,
-        repository_ctx.attr.overlay_path,
-    )
+    src_path = repository_ctx.path(Label("//:WORKSPACE")).dirname
+    bazel_path = src_path.get_child("utils").get_child("bazel")
+    overlay_path = bazel_path.get_child("llvm-project-overlay")
+    script_path = bazel_path.get_child("overlay_directories.py")
 
-    overlay_script = repository_ctx.path(
-        repository_ctx.attr._overlay_script,
-    )
     python_bin = repository_ctx.which("python3")
     if not python_bin:
         # Windows typically just defines "python" as python3. The script itself
@@ -61,7 +48,7 @@ def _overlay_directories(repository_ctx):
 
     cmd = [
         python_bin,
-        overlay_script,
+        script_path,
         "--src",
         src_path,
         "--overlay",
@@ -98,14 +85,6 @@ llvm_configure = repository_rule(
     local = True,
     configure = True,
     attrs = {
-        "_overlay_script": attr.label(
-            default = Label("//:overlay_directories.py"),
-            allow_single_file = True,
-        ),
-        "overlay_workspace": attr.label(default = Label("//:WORKSPACE")),
-        "overlay_path": attr.string(default = DEFAULT_OVERLAY_PATH),
-        "src_workspace": attr.label(default = Label("//:WORKSPACE")),
-        "src_path": attr.string(mandatory = True),
         "targets": attr.string_list(default = DEFAULT_TARGETS),
     },
 )

utils/bazel/examples/http_archive/WORKSPACE

@@ -14,8 +14,8 @@ http_archive(
     name = "bazel_skylib",
     sha256 = "97e70364e9249702246c0e9444bccdc4b847bed1eb03c5a3ece4f83dfe6abc44",
     urls = [
-        "https://mirror.bazel.build/github.com/bazelbuild/bazel-skylib/releases/download/{version}/bazel-skylib-{version}.tar.gz".format(version=SKYLIB_VERSION),
-        "https://github.com/bazelbuild/bazel-skylib/releases/download/{version}/bazel-skylib-{version}.tar.gz".format(version=SKYLIB_VERSION),
+        "https://mirror.bazel.build/github.com/bazelbuild/bazel-skylib/releases/download/{version}/bazel-skylib-{version}.tar.gz".format(version = SKYLIB_VERSION),
+        "https://github.com/bazelbuild/bazel-skylib/releases/download/{version}/bazel-skylib-{version}.tar.gz".format(version = SKYLIB_VERSION),
     ],
 )