Re: When should ralloc.c be used?

[Daniel Colascione]

"Perry E. Metzger" <address@hidden> writes:

> On Thu, 27 Oct 2016 14:07:46 -0700 Daniel Colascione
> <address@hidden> wrote:
>> If we need a compiler to make this happen, so be it. We'll just
>> require libgcc, or hell, check it in to the repository, the way gcc
>> checks in its dependencies.
>> 
>> An additional benefit of integrating with a compiler at runtime is
>> the potential to JIT elisp code. Both LLVM and GCC these days have
>> usable JIT interfaces. We could even serialize JIT traces in these
>> user Emacs dumps.
>
> Having a JIT for emacs bytecode (or some other IR) would be really
> superb. I had no idea that GCC now had JIT support, but if it is as
> easy to use as LLVM's, a prototype would not be a hard project. (I
> presume RMS would insist on GCC as the basis.)

GCC's interface isn't nearly as mature as LLVM's yet, but there's promise

https://gcc.gnu.org/wiki/JIT

> Of course, given that Emacs already byte compiles everything, maybe
> going straight to machine code rather than the bytecode + JIT would
> be good? Again, I don't know what GCC's infra is like, but if it is
> as good as LLVM's that would be quite straightforward.

AOT is all the rage right now (JEP 295), but I believe that tracing JITs
are ultimately the right choice for code density and installation
latency reasons. But this is one of those arguments that's never going
to be solved.