This is true to this day per IRONSIDES paper [1]. Made me consider using Ada as an executable specification language to be converted to equivalent C/C++ and compiled that way. They need to just do a functional implementation of the compiler in a language such as Ocaml with extensive testing. That's what Esterel did for SCADE generator. They said Ocaml compiler stages were easy to trace down to object code. So, that helps with the chicken and egg problem a bit. Alternatively, implement it in the VLISP, PreScheme, or VeriML that were formally verified for correctness.

[1] http://ironsides.martincarlisle.com/globecom_2012.pdf