Horton

Re: JIT compiling with LLVM v9.0

Andres Freund <andres@anarazel.de>

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From: Andres Freund <andres@anarazel.de>
To: Thomas Munro <thomas.munro@enterprisedb.com>
Cc: Robert Haas <robertmhaas@gmail.com>, Jeff Davis <pgsql@j-davis.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2018-01-31T02:05:33Z
Lists: pgsql-hackers 
On 2018-01-31 14:42:26 +1300, Thomas Munro wrote:
> I'm just starting to look at this (amazing) work, and I don't have a
> strong opinion yet.  But certainly, making it easy for packagers to
> put the -jit stuff into a separate package for the reasons already
> given sounds sensible to me.  Some systems package LLVM as one
> gigantic package that'll get you 1GB of compiler/debugger/other stuff
> and perhaps violate local rules by installing a compiler when you
> really just wanted libLLVM{whatever}.so.  I guess it should be made
> very clear to users (explain plans, maybe startup message, ...?)

I'm not quite sure I understand. You mean have it display whether
available? I think my plan is to "just" set jit_expressions=on (or
whatever we're going to name it) fail if the prerequisites aren't
available. I personally don't think this should be enabled by default,
definitely not in the first release.

> $ c++ -v
> FreeBSD clang version 4.0.0 (tags/RELEASE_400/final 297347) (based on
> LLVM 4.0.0)
> 
> This seems to be a valid complaint.  I don't think you should be
> (indirectly) wrapping Types.h in extern "C".  At a guess, your
> llvmjit.h should be doing its own #ifdef __cplusplus'd linkage
> specifiers, so you can use it from C or C++, but making sure that you
> don't #include LLVM's headers from a bizarro context where __cplusplus
> is defined but the linkage is unexpectedly already "C"?

Hm, this seems like a bit of pointless nitpickery by the compiler to me,
but I guess...

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".