Horton

Re: JIT compiling with LLVM v11

Andres Freund <andres@anarazel.de>

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From: Andres Freund <andres@anarazel.de>
To: Thomas Munro <thomas.munro@enterprisedb.com>
Cc: Pg Hackers <pgsql-hackers@postgresql.org>, Pierre Ducroquet <p.psql@pinaraf.info>
Date: 2018-03-15T00:20:17Z
Lists: pgsql-hackers 
Hi,

On 2018-03-13 15:29:33 -0700, Andres Freund wrote:
> On 2018-03-14 10:32:40 +1300, Thomas Munro wrote:
> > I decided to try this on a CentOS 7.2 box.  It has LLVM 3.9 in the
> > 'epel' package repo, but unfortunately it only has clang 3.4.
> 
> That's a bit odd, given llvm and clang really live in the same repo...

I don't really live in the RHEL world, but I wonder if
https://developers.redhat.com/blog/2017/10/04/red-hat-adds-go-clangllvm-rust-compiler-toolsets-updates-gcc/
is relevant?
Appears to be available on centos too
https://www.softwarecollections.org/en/scls/rhscl/devtoolset-7/


I checked it out and supporting 3.4 would be a bit painful due to not
being able to directly emit module summaries. We could support that by
building the summaries separately using LLVM, but that'd be either
slower for everyone, or we'd need somewhat finnicky conditionals.


> > clang: error: unknown argument: '-fexcess-precision=standard'
> > clang: error: unknown argument: '-flto=thin'
> >
> > Ok, so I hacked src/Makefile.global.in to remove -flto=thin.
> 
> I think I can get actually rid of that entirely.

Err, no, not really. Would increase overhead due to separate module
summary generation, so I'd rather not do it.


> > It looks
> > like -fexcess-precision-standard is coming from a configure test that
> > was run against ${CC}, not against ${CLANG}, so I hacked the generated
> > src/Makefile.global to remove that too, just to see if I could get
> > past that.
> 
> Yea, I'd hoped we could avoid duplicating all the configure tests, but
> maybe not :(.

I've mostly done that now (not pushed).  I've created new
PGAC_PROG_VARCC_VARFLAGS_OPT(compiler variable, flag variable, testflag)
function, which now is used to implement PGAC_PROG_CC_CFLAGS_OPT and
PGAC_PROG_CC_VAR_OPT (similar for CXX).  That makes it reasonable to
test the variables clang recognizes separately.


Greetings,

Andres Freund

Commits

  1. Improve JIT docs.

  2. Add documentation for the JIT feature.

  3. Add EXPLAIN support for JIT.

  4. Add inlining support to LLVM JIT provider.

  5. JIT tuple deforming in LLVM JIT provider.

  6. Add FIELDNO_* macro designating offset into structs required for JIT.

  7. Add expression compilation support to LLVM JIT provider.

  8. Expand list of synchronized types and functions in LLVM JIT provider.

  9. Add helpers for emitting LLVM IR.

  10. Basic planner and executor integration for JIT.

  11. Debugging and profiling support for LLVM JIT provider.

  12. Support for optimizing and emitting code in LLVM JIT provider.

  13. Add file containing extensions of the LLVM C API.

  14. Basic JIT provider and error handling infrastructure.

  15. Add configure infrastructure (--with-llvm) to enable LLVM support.

  16. Add C++ support to configure.

  17. Add PGAC_PROG_VARCC_VARFLAGS_OPT autoconf macro.

  18. Fix VM buffer pin management in heap_lock_updated_tuple_rec().

  19. Allow tupleslots to have a fixed tupledesc, use in executor nodes.

  20. Expression evaluation based aggregate transition invocation.

  21. Perform slot validity checks in a separate pass over expression.

  22. Rely on executor utils to build targetlist for DML RETURNING.

  23. Refer to OS X as "macOS", except for the port name which is still "darwin".