Re: [HACKERS] WIP: Faster Expression Processing and Tuple Deforming(including JIT)

Hi,

On 2017-02-10 18:18:13 +0100, Markus Nullmeier wrote:
> Well, if this thread of thought about hand-crafted JIT should be taken
> up again by someone at some point in time, I guess it could be possible
> to reuse tools that are already out there, such as "DynASM"
> ( http://luajit.org/dynasm_features.html ) from the LuaJIT project
> (currently offers x86-64, x86-32, ARM-32, PPC-32, and MIPS-32).
> Maybe one could even recycle parts of the LuaJIT project itself
> ( http://luajit.org/luajit.html ,
>   http://article.gmane.org/gmane.comp.lang.lua.general/58908 ).

FWIW, I'd looked at dynasm/luajit.

One big reason to go for LLVM is that it has nearly all the
infrastructure to make backend-functions/operators inlineable.
Especially for some of the arithmetic operations and such, that'd be
quite useful performance-wise.  With LLVM you can just use clang on C to
generate the IR, do some work to boil down the IR modules to the
relevant functions (i.e. remove non sql-callable functions), for which
LLVM has infrastructure, and then inline the functions that way.  That's
a lot harder to do with nearly everything else (save gcc's jit library,
but the licensing and stability situation makes that unattractive.

Greetings,

Andres Freund