diff --git a/lldb/test/Shell/helper/build.py b/lldb/test/Shell/helper/build.py
--- a/lldb/test/Shell/helper/build.py
+++ b/lldb/test/Shell/helper/build.py
@@ -4,6 +4,7 @@
 
 import argparse
 import os
+import shutil
 import signal
 import subprocess
 import sys
@@ -170,16 +171,14 @@
         print('    {0} = {1}'.format(e, formatted_value))
 
 def find_executable(binary_name, search_paths):
-    if sys.platform == 'win32':
-        binary_name = binary_name + '.exe'
-
-    search_paths = os.pathsep.join(search_paths)
-    paths = search_paths + os.pathsep + os.environ.get('PATH', '')
-    for path in paths.split(os.pathsep):
-        p = os.path.join(path, binary_name)
-        if os.path.exists(p) and not os.path.isdir(p):
-            return os.path.normpath(p)
-    return None
+    # shutil.which will ignore PATH if given a path argument, we want to include it.
+    search_paths.append(os.environ.get('PATH', ''))
+    search_path = os.pathsep.join(search_paths)
+    binary_path = shutil.which(binary_name, path=search_path)
+    if binary_path is not None:
+        # So for example, we get '/bin/gcc' instead of '/usr/../bin/gcc'.
+        binary_path = os.path.normpath(binary_path)
+    return binary_path
 
 def find_toolchain(compiler, tools_dir):
     if compiler == 'msvc':