Fork channel

Create a new channel as a copy of main.

Rename channel

Rename main to:

Delete channel

Delete main? This cannot be undone.

cfi-unfinished-frame.s
// RUN: not llvm-mc -filetype=asm -triple x86_64-pc-linux-gnu %s -o %t 2>%t.out
// RUN: FileCheck -input-file=%t.out %s

.cfi_startproc
// CHECK: Unfinished frame