diff --git a/llvm/cmake/modules/AddLLVM.cmake b/llvm/cmake/modules/AddLLVM.cmake
--- a/llvm/cmake/modules/AddLLVM.cmake
+++ b/llvm/cmake/modules/AddLLVM.cmake
@@ -1549,9 +1549,11 @@
 # use it and can't be in a lit module. Use with make_paths_relative().
 string(CONCAT LLVM_LIT_PATH_FUNCTION
   "# Allow generated file to be relocatable.\n"
+  "from pathlib import Path\n"
   "def path(p):\n"
   "    if not p: return ''\n"
-  "    return os.path.join(os.path.dirname(os.path.abspath(__file__)), p)\n"
+  "    abs = Path(__file__).resolve().parent / p\n"
+  "    return str(abs.resolve())\n"
   )
 
 # This function provides an automatic way to 'configure'-like generate a file
diff --git a/llvm/utils/lit/lit/discovery.py b/llvm/utils/lit/lit/discovery.py
--- a/llvm/utils/lit/lit/discovery.py
+++ b/llvm/utils/lit/lit/discovery.py
@@ -53,8 +53,7 @@
         config_map = litConfig.params.get('config_map')
         if config_map:
             cfgpath = os.path.realpath(cfgpath)
-            cfgpath = os.path.normcase(cfgpath)
-            target = config_map.get(cfgpath)
+            target = config_map.get(os.path.normcase(cfgpath))
             if target:
                 cfgpath = target