--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/llvm/test/TableGen/JSON-check.py	Thu Feb 13 15:10:13 2020 +0900
@@ -0,0 +1,51 @@
+#!/usr/bin/env python
+
+import sys
+import subprocess
+import traceback
+import json
+
+data = json.load(sys.stdin)
+testfile = sys.argv[1]
+
+prefix = "CHECK: "
+
+fails = 0
+passes = 0
+with open(testfile) as testfh:
+    lineno = 0
+    for line in iter(testfh.readline, ""):
+        lineno += 1
+        line = line.rstrip("\r\n")
+        try:
+            prefix_pos = line.index(prefix)
+        except ValueError:
+            continue
+        check_expr = line[prefix_pos + len(prefix):]
+
+        try:
+            exception = None
+            result = eval(check_expr, {"data":data})
+        except Exception:
+            result = False
+            exception = traceback.format_exc().splitlines()[-1]
+
+        if exception is not None:
+            sys.stderr.write(
+                "{file}:{line:d}: check threw exception: {expr}\n"
+                "{file}:{line:d}: exception was: {exception}\n".format(
+                    file=testfile, line=lineno,
+                    expr=check_expr, exception=exception))
+            fails += 1
+        elif not result:
+            sys.stderr.write(
+                "{file}:{line:d}: check returned False: {expr}\n".format(
+                    file=testfile, line=lineno, expr=check_expr))
+            fails += 1
+        else:
+            passes += 1
+
+if fails != 0:
+    sys.exit("{} checks failed".format(fails))
+else:
+    sys.stdout.write("{} checks passed\n".format(passes))