diff --git a/scripts/llvm.py b/scripts/llvm.py
index 13e5de6..829c720 100644
--- a/scripts/llvm.py
+++ b/scripts/llvm.py
@@ -20,24 +20,9 @@
     exit(1)
 
 
-def get_llvm_root():
-    """Get the path to the LLVM root, which contains the repos as well as all
-    the work environments."""
-    return os.environ["LLVM_ROOT"]
-
-
 def get_worktree_root(env):
-    """
-    Get the path to the LLVM worktree corresponding to env. The value will be
-    based on the LLVM root.
-    """
-    return os.path.join(get_llvm_root(), env, "llvm")
-
-# Figure out the path to the LLVM repos
-if "LLVM_ROOT" not in os.environ:
-    die("Please, define $LLVM_ROOT to point to the root\n"
-        "path where the worktree setup should be performed")
-llvm_repos_root = os.path.join(get_llvm_root(), "repos")
+    """Get the path to the LLVM worktree corresponding to env."""
+    return os.path.join(env, "llvm")
 
 
 def dump_config(config):
@@ -58,6 +43,7 @@
     proj = Proj()
 
     llvm_worktree_root = get_worktree_root(args.env)
+    llvm_repos_root = args.repos
     config = LLVMSourceConfig(proj, llvm_worktree_root)
 
     if not args.add and not args.remove:
@@ -87,7 +73,13 @@
 valid_subprojects = list(LLVMSubproject.get_all_subprojects().keys())
 
 options = ArgumentParser(formatter_class=RawTextHelpFormatter)
-options.add_argument('env', help="The environment to update.")
+options.add_argument(
+    '--env',
+    required=True,
+    help="Path to the environment to update.")
+options.add_argument(
+    '--repos', required=True,
+    help="Path to the directory containing the repositories for all LLVM subprojects.")
 
 subcommands = options.add_subparsers()