1 files changed, 14 insertions, 0 deletions
diff --git a/src/runtime.js b/src/runtime.js
index e42f90e3..9104c55d 100644
--- a/src/runtime.js
+++ b/src/runtime.js
@@ -403,6 +403,20 @@ var Runtime = {
         }
       });
     }
+
+    var newLength = table.length;
+    jsModule.cleanups.push(function() {
+      if (table.length === newLength) {
+        table.length = from; // nothing added since, just shrink
+      } else {
+        // something was added above us, clear and leak the span
+        for (var i = 0; i < num; i++) {
+          table[from + i] = null;
+        }
+      }
+      while (table.length > 0 && table[table.length-1] === null) table.pop();
+    });
+
     // patch js module dynCall_* to use functionTable
     sigs.forEach(function(sig) {
       jsModule['dynCall_' + sig] = function() {