Index: .gn
===================================================================
--- .gn
+++ .gn
@@ -0,0 +1,14 @@
+# LLVM's GN build is unsupported, see llvm/utils/gn/README.rst for details.
+
+buildconfig = "//llvm/utils/gn/build/BUILDCONFIG.gn"
+
+# Disallow all calls to exec_script. We should be very conservative about
+# whitelisting things here.
+exec_script_whitelist = []
+
+# The normal GN setup is to have BUILD.gn files in-tree and a root BUILD.gn
+# file.  Since LLVM's GN build is unofficial, set secondary_source to tell GN
+# that e.g. llvm/lib/Demangle/BUILD.gn is found at
+# llvm/utils/gn/secondary/llvm/lib/Demangle/BUILD.gn and that the root BUILD.gn
+# file is at llvm/utils/gn/secondary/BUILD.gn
+secondary_source = "//llvm/utils/gn/secondary/"