Revert "fix frontend.cpp"

This reverts commit 1e51baab124400f70a57084888fc2f9e743ef3d3.
Revert "fix frontend.cpp"

This reverts commit e8294870008d510736a870775a676bdfc1e7e8c1.
Revert "update e2"

This reverts commit 84f410fc6f13ee43d98d7e713ddf1204cb00c83d.