[pklausler]

> I may be wrong but I imagine very few compilers were written in “high-level” languages (PL/I notwithstanding) until C took off in the latter half of the 1980s,

There was an interesting time in the late 70's when many vendors had their own high-level systems software development programming languages: CDC's Cybil, Sperry-UNIVAC's PLUS, &c., and these were often used for compiler development as a replacement for assembly language. At Cray, the CFT compiler was in assembly language, and CFT77 was in Pascal.