diff --git a/libcxx/utils/libcxx/test/dsl.py b/libcxx/utils/libcxx/test/dsl.py
--- a/libcxx/utils/libcxx/test/dsl.py
+++ b/libcxx/utils/libcxx/test/dsl.py
@@ -20,6 +20,8 @@
 import lit.TestRunner
 import lit.util
 
+class ConfigurationError(Exception):
+  pass
 
 def _memoizeExpensiveOperation(extractCacheKey):
   """
@@ -105,7 +107,7 @@
   with _makeConfigTest(config) as test:
     with open(test.getSourcePath(), 'w') as sourceFile:
       sourceFile.write(source)
-    out, err, exitCode, timeoutInfo = _executeScriptInternal(test, ['%{build}'])
+    _, _, exitCode, _ = _executeScriptInternal(test, ['%{build}'])
     _executeScriptInternal(test, ['rm %t.exe'])
     return exitCode == 0
 
@@ -115,9 +117,9 @@
   Compiles a program for the test target, run it on the test target and return
   the output.
 
-  If the program fails to compile or run, None is returned instead. Note that
-  execution of the program is done through the %{exec} substitution, which means
-  that the program may be run on a remote host depending on what %{exec} does.
+  Note that execution of the program is done through the %{exec} substitution,
+  which means that the program may be run on a remote host depending on what
+  %{exec} does.
   """
   if args is None:
     args = []
@@ -125,13 +127,13 @@
     with open(test.getSourcePath(), 'w') as source:
       source.write(program)
     try:
-      _, _, exitCode, _ = _executeScriptInternal(test, ['%{build}'])
+      _, err, exitCode, _ = _executeScriptInternal(test, ['%{build}'])
       if exitCode != 0:
-        return None
+        raise ConfigurationError("Failed to build program, stderr is:\n{}".format(err))
 
       out, err, exitCode, _ = _executeScriptInternal(test, ["%{{run}} {}".format(' '.join(args))])
       if exitCode != 0:
-        return None
+        raise ConfigurationError("Failed to run program, stderr is:\n{}".format(err))
 
       actualOut = re.search("# command output:\n(.+)\n$", out, flags=re.DOTALL)
       actualOut = actualOut.group(1) if actualOut else ""
@@ -194,20 +196,17 @@
 
   If the optional `flags` argument (a string) is provided, these flags will
   be added to the compiler invocation when generating the macros.
-
-  If we fail to extract the compiler macros because of a compiler error, None
-  is returned instead.
   """
   with _makeConfigTest(config) as test:
     with open(test.getSourcePath(), 'w') as sourceFile:
       # Make sure files like <__config> are included, since they can define
       # additional macros.
       sourceFile.write("#include <stddef.h>")
-    unparsedOutput, err, exitCode, timeoutInfo = _executeScriptInternal(test, [
+    unparsedOutput, err, exitCode, _ = _executeScriptInternal(test, [
       "%{{cxx}} %s -dM -E %{{flags}} %{{compile_flags}} {}".format(flags)
     ])
     if exitCode != 0:
-      return None
+      raise ConfigurationError("Failed to retrieve compiler macros, stderr is:\n{}".format(err))
     parsedMacros = dict()
     defines = (l.strip() for l in unparsedOutput.split('\n') if l.startswith('#define '))
     for line in defines: