Rollup of 8 pull requests#80566

Merged

bors merged 31 commits intorust-lang:masterfrom

Dylan-DPC-zz:rollup-rns6est

Jan 1, 2021

Commits on Dec 23, 2020

Update and improve `rustc_codegen_{llvm,ssa}` docs
camelid
committed

Commits on Dec 25, 2020

Commits on Dec 30, 2020

Commits on Dec 31, 2020