[mikemike]

I'm not sure one can infer anything from a single failed Mozilla project.

'Real-world' JavaScript is a challenge for any compiler, no matter the underlying technology.

The technical debt in SpiderMonkey (at that time, anyway) was eye-watering. Grafting anything on top of that was hard. They haven't even gotten to the point of implementing the crucial pieces of a trace compiler before the project folded.

Trace compilers make nice textbook exercises. Getting them into production is a different matter: region selection, side-exit handling, trace graph evolution, deep VM integration, code generation adapted to all of this … far from trivial, but doable.

Neither is it trivial to create a production-quality method-at-a-time JIT compiler and VM for a dynamic language.

Ceterum censeo: The fundamental papers on trace compilation are from Fisher (1981) and the teams around Multiflow (1990) and Dynamo (1999). Franz, Gal, et al can be credited for later re-popularizing the idea, but they haven't added anything of note.