diff --git a/util/bot/update_clang.py b/util/bot/update_clang.py
index 9595c0a..70abf41 100644
--- a/util/bot/update_clang.py
+++ b/util/bot/update_clang.py
@@ -27,7 +27,7 @@
 # Path constants. (All of these should be absolute paths.)
 THIS_DIR = os.path.abspath(os.path.dirname(__file__))
 LLVM_BUILD_DIR = os.path.join(THIS_DIR, 'llvm-build')
-STAMP_FILE = os.path.join(THIS_DIR, 'cr_build_revision')
+STAMP_FILE = os.path.join(LLVM_BUILD_DIR, 'cr_build_revision')
 
 # URL for pre-built binaries.
 CDS_URL = os.environ.get('CDS_CLANG_BUCKET_OVERRIDE',