Horton

Re: JIT compiling with LLVM v12.2

Andres Freund <andres@anarazel.de>

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From: Andres Freund <andres@anarazel.de>
To: Thomas Munro <thomas.munro@enterprisedb.com>
Cc: Stephen Frost <sfrost@snowman.net>, Pg Hackers <pgsql-hackers@postgresql.org>
Date: 2018-03-21T20:59:03Z
Lists: pgsql-hackers 
On 2018-03-22 09:51:01 +1300, Thomas Munro wrote:
> On Thu, Mar 22, 2018 at 9:09 AM, Andres Freund <andres@anarazel.de> wrote:
> > Hi,
> >
> > On 2018-03-22 09:00:19 +1300, Thomas Munro wrote:
> >> 64 bit CPU, 32 bit OS.  I didn't try Debian multi-arch i386 support on
> >> an amd64 system, but that's probably an easier way to do this if you
> >> already have one of those...
> >
> > Ah, then I think I might know what happend. Does it start to work if you
> > replace the auto-detected cpu with "x86"? I think what might happen is
> > that it generates 64bit code, because of the detected CPU name.
> 
> Hah, that makes sense.  I tried setting cpu to "x86", and now it fails
> differently:

Did you change the variable, or replace the value that's passed to the
LLVMCreateTargetMachine() calls?  If you did the former, the error
wouldn't be surprising, because
	LLVMDisposeMessage(cpu);
	cpu = NULL;
will attempt to free the return value of LLVMGetHostCPUName(), which'll
obviously not work if you just set to a constant.

> #1  0xb7593806 in _int_free (av=0xae700220
> <llvm::SystemZ::GRX32BitRegClass>, p=0xae75f273, have_lock=0) at
> malloc.c:3905
> #2  0xabd05cd8 in LLVMDisposeMessage () from
> /usr/lib/i386-linux-gnu/libLLVM-3.9.so.1
> #3  0xae75100b in llvm_session_initialize () at llvmjit.c:636
> #4  llvm_create_context (jitFlags=15) at llvmjit.c:136
> #5  0xae75d3e9 in llvm_compile_expr (state=0x2616e60) at llvmjit_expr.c:132
> #6  0x00650118 in ExecReadyExpr (state=state@entry=0x2616e60) at execExpr.c:627
> #7  0x00652dd7 in ExecInitExpr (node=0x2666bb4, parent=0x261693c) at
> execExpr.c:144
> ...


FWIW, a 32bit chroot, on a 64bit kernel works:

2018-03-21 20:57:56.576 UTC [3708] DEBUG:  successfully loaded LLVM in current session
2018-03-21 20:57:56.577 UTC [3708] DEBUG:  JIT detected CPU "skylake", with features "+sse2,+cx16,-tbm,-avx512ifma,-avx512dq,-fma4,+prfchw,+bmi2,+xsavec,+fsgsbase,+popcnt,+aes,-pcommit,+xsaves,-avx512er,-clwb,-avx512f,-pku,+smap,+mmx,-xop,+rdseed,+hle,-sse4a,-avx512bw,+clflushopt,+xsave,-avx512vl,+invpcid,-avx512cd,+avx,+rtm,+fma,+bmi,-mwaitx,+rdrnd,+sse4.1,+sse4.2,+avx2,+sse,+lzcnt,+pclmul,-prefetchwt1,+f16c,+ssse3,+sgx,+cmov,-avx512vbmi,+movbe,+xsaveopt,-sha,+adx,-avx512pf,+sse3"
2018-03-21 20:57:56.579 UTC [3708] DEBUG:  time to inline: 0.000s, opt: 0.000s, emit: 0.002s

that's debian testing though.

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".