ext: Update ply to version 3.11.

We had been using version 3.2 from 2009, which does not have support for
t_eof().

Change-Id: Id5610a272fe2cecd586991f4c59f3ec77184164e
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/56342
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Reviewed-by: Bobby Bruce <bbruce@ucdavis.edu>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>

ext/ply/test/testcpp.py

@@ -0,0 +1,101 @@
+from unittest import TestCase, main
+
+from multiprocessing import Process, Queue
+from six.moves.queue import Empty
+
+import sys
+
+if ".." not in sys.path:
+    sys.path.insert(0, "..")
+
+from ply.lex import lex
+from ply.cpp import *
+
+
+def preprocessing(in_, out_queue):
+    out = None
+
+    try:
+        p = Preprocessor(lex())
+        p.parse(in_)
+        tokens = [t.value for t in p.parser]
+        out = "".join(tokens)
+    finally:
+        out_queue.put(out)
+
+class CPPTests(TestCase):
+    "Tests related to ANSI-C style lexical preprocessor."
+
+    def __test_preprocessing(self, in_, expected, time_limit = 1.0):
+        out_queue = Queue()
+
+        preprocessor = Process(
+            name = "PLY`s C preprocessor",
+            target = preprocessing,
+            args = (in_, out_queue)
+        )
+
+        preprocessor.start()
+
+        try:
+            out = out_queue.get(timeout = time_limit)
+        except Empty:
+            preprocessor.terminate()
+            raise RuntimeError("Time limit exceeded!")
+        else:
+            self.assertMultiLineEqual(out, expected)
+
+    def test_concatenation(self):
+        self.__test_preprocessing("""\
+#define a(x) x##_
+#define b(x) _##x
+#define c(x) _##x##_
+#define d(x,y) _##x##y##_
+
+a(i)
+b(j)
+c(k)
+d(q,s)"""
+            , """\
+
+
+
+
+
+i_
+_j
+_k_
+_qs_"""
+        )
+
+    def test_deadloop_macro(self):
+        # If there is a word which equals to name of a parametrized macro, then
+        # attempt to expand such word as a macro manages the parser to fall
+        # into an infinite loop.
+
+        self.__test_preprocessing("""\
+#define a(x) x
+
+a;"""
+            , """\
+
+
+a;"""
+        )
+
+    def test_index_error(self):
+        # If there are no tokens after a word ("a") which equals to name of
+        # a parameterized macro, then attempt to expand this word leads to
+        # IndexError.
+
+        self.__test_preprocessing("""\
+#define a(x) x
+
+a"""
+            , """\
+
+
+a"""
+        )
+
+main()