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: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>, Pg Hackers <pgsql-hackers@postgresql.org>, Pierre Ducroquet <p.psql@pinaraf.info>
Date: 2018-03-08T20:12:09Z
Lists: pgsql-hackers 
On 2018-03-08 11:58:41 -0800, Andres Freund wrote:
> I think we can easily fix this by behaving like clang, which uses
> llvm::sys::getHostCPUFeatures(HostFeatures) to built the feature list:
> 
>   // If -march=native, autodetect the feature list.
>   if (const Arg *A = Args.getLastArg(clang::driver::options::OPT_march_EQ)) {
>     if (StringRef(A->getValue()) == "native") {
>       llvm::StringMap<bool> HostFeatures;
>       if (llvm::sys::getHostCPUFeatures(HostFeatures))
>         for (auto &F : HostFeatures)
>           Features.push_back(
>               Args.MakeArgString((F.second ? "+" : "-") + F.first()));
>     }
>   }
> 
> which seems easy enough.

Or even in core LLVM, which has this nice comment:

  // If user asked for the 'native' CPU, we need to autodetect features.
  // This is necessary for x86 where the CPU might not support all the
  // features the autodetected CPU name lists in the target. For example,
  // not all Sandybridge processors support AVX.
  if (MCPU == "native") {

which pretty much describes the issue you're apparently hitting.

I've pushed an attempted fix (needs a comment, but works here).

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".