To be fair, compilers and linkers can be thought of as pure functions (if we ignore stuff like including timestamps in builds e.g.). They have no special requir

To be fair, compilers and linkers can be thought of as pure functions (if we ignore stuff like including timestamps in builds e.g.). They have no special requirements language-wise. You can write them in any general purpose programming language. Even Brainfuck will do (for one-file programs fed through stdin). No argument about the others though. Although I guess JIT compilers may be classified as systems programming, since you need to do some OS-specific tricks with virtual memory during execution of the compiler.