[threadsafety] Fix exception thrown by list of actuals and formals not having the same length in some cases (C++?)

Reviewed By: jberdine

Differential Revision: D5995583

fbshipit-source-id: 2d3debf

infer/src/checkers/ThreadSafety.ml

@@ -581,7 +581,7 @@ module TransferFunctions (CFG : ProcCfg.S) = struct
     let open Domain in
     let formals, _ = FormalMap.make pdesc |> FormalMap.get_formals_indexes |> List.unzip in
     let fmls_actls =
-      List.zip_exn formals actuals
+      List.zip_exn formals (List.take actuals (List.length formals))
       |> List.filter_map ~f:(fun (fml, act) ->
              match get_access_path act with Some path -> Some (fml, path) | _ -> None )
     in

infer/tests/codetoanalyze/cpp/threadsafety/variadic.cpp

@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2017 - present Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+#include <cstdarg>
+#include <cstdio>
+
+double average(int count, ...) {
+  va_list ap;
+  int j;
+  double sum = 0;
+
+  va_start(ap,
+           count); /* Requires the last fixed parameter (to get the address) */
+  for (j = 0; j < count; j++) {
+    sum += va_arg(ap, int); /* Increments ap to the next argument. */
+  }
+  va_end(ap);
+
+  return sum / count;
+}
+
+int main(int argc, char const* argv[]) {
+  printf("%f\n", average(3, 1, 2, 3));
+  return 0;
+}