Fix FMCallExpression undefined shift behaviour.

When determining which params should be an object and which are a value it is
possible to overflow the int on the shift comparision (if there are more then
32 arguments).

This never happens in practise as it's a controlled list of method calls which
we pass objects for. Cap the check at 32 for the shifting so it doesn't
overflow. We can revisit and extend the value later if we ever have an internal
formcalc method that needs an object in a position greater then 32.

BUG=chromium:603490

Review-Url: https://codereview.chromium.org/2206253002

1 files changed, 1 insertions, 0 deletions

diff --git a/BUILD.gn b/BUILD.gn
index 6b5e78d49a..a03102aa7a 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -1578,6 +1578,7 @@ test("pdfium_unittests") {
       "xfa/fde/xml/fde_xml_imp_unittest.cpp",
       "xfa/fxbarcode/pdf417/BC_PDF417HighLevelEncoder_unittest.cpp",
       "xfa/fxfa/app/xfa_textlayout_unittest.cpp",
+      "xfa/fxfa/fm2js/xfa_simpleexpression_unittest.cpp",
       "xfa/fxfa/parser/xfa_utils_unittest.cpp",
     ]
   }