Horton

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

Andres Freund <andres@anarazel.de>

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From: Andres Freund <andres@anarazel.de>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-hackers@postgresql.org, Heikki Linnakangas <hlinnaka@iki.fi>, Doug Doole <ddoole@salesforce.com>
Date: 2016-12-06T19:47:08Z
Lists: pgsql-hackers 
On 2016-12-06 11:10:59 -0800, Andres Freund wrote:
> > * Are there any currently-interesting platforms that LLVM doesn't work
> > for?  (I'm worried about RISC-V as much as legacy systems.)
> 
> LLVM itself I don't think is a problem, it seems to target a wide range
> of platforms. The platforms that don't support JIT compiling might be a
> bit larger, since that involves more than just generating code.

The os specific part is handling the executable format. The JIT we'd be
using (MCJIT) has support for ELF, MachO, and COFF. The architecture
specific bits seem to be there for x86, arm (small endian, be), aarch64
(arm 64 bits be/le again), mips, ppc64.

Somebody is working on RISC-V support for llvm (i.e. it appears to be
working, but is not merged) - but given it's not integrated into gcc
either, I'm not seing that being an argument.

Greetings,

Andres Freund

Commits

  1. Improve performance of ExecEvalWholeRowVar.

  2. Remove unreachable code in expression evaluation.

  3. Faster expression evaluation and targetlist projection.

  4. Avoid syntax error on platforms that have neither LOCALE_T nor ICU.

  5. Add configure test to see if the C compiler has gcc-style computed gotos.

  6. Improve regression test coverage for TID scanning.

  7. Improve expression evaluation test coverage.

  8. Fix two errors with nested CASE/WHEN constructs.