BOOM! Typed, assembly language is exactly what I was going to recommend! TALC assembly, Chlipala's Bedrock, and Microsoft's CoqASM are Google keywords to use for anyone following along.
CakeML or Verisoft's C0 could be useful for assembly generation but not as sure there. Tough constraints in JIT. Edited to add Myreen's JIT that I just remembered.
Not that Im aware of. They might privately license it if asked. I mainly bring it up as something worth cloning by FOSS team given there's plenty details in paper. Meanwhile, look up Magnus Myreen's publications and software as they're on a row with verified everything.
CakeML or Verisoft's C0 could be useful for assembly generation but not as sure there. Tough constraints in JIT. Edited to add Myreen's JIT that I just remembered.
http://citeseerx.ist.psu.edu/viewdoc/download;jsessionid=F58...