"returnFromJavaScript" should actually be renamed to "handleUncaughtException" because that is what it actually does.
Created attachment 219030 [details] the patch.
Created attachment 219031 [details] patch 2: missed LowLevelInterpreter32_64.asm
Thanks for the review. Landed in r160497 on the jsCStack branch: <http://trac.webkit.org/r160497>.