From 68f1c50927c7b83e8e7d89fe18be2a9e0d2633d3 Mon Sep 17 00:00:00 2001
From: "brendan%mozilla.org" <brendan%mozilla.org>
Date: Sat, 7 Oct 2006 03:50:08 +0000
Subject: [PATCH] Simple null defense in js_PCToLineNumber (355341, r=igor).

---
 js/src/jsscript.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/js/src/jsscript.c b/js/src/jsscript.c
index fabf3e45b7e..0691e0d3197 100644
--- a/js/src/jsscript.c
+++ b/js/src/jsscript.c
@@ -1441,6 +1441,10 @@ js_PCToLineNumber(JSContext *cx, JSScript *script, jsbytecode *pc)
     jssrcnote *sn;
     JSSrcNoteType type;
 
+    /* Cope with JSStackFrame.pc value prior to entering js_Interpret. */
+    if (!pc)
+        return 0;
+
     /*
      * Special case: function definition needs no line number note because
      * the function's script contains its starting line number.