Horton

Re: JIT compiling with LLVM v11

Thomas Munro <thomas.munro@enterprisedb.com>

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From: Thomas Munro <thomas.munro@enterprisedb.com>
To: Andres Freund <andres@anarazel.de>
Cc: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>, Pg Hackers <pgsql-hackers@postgresql.org>, Pierre Ducroquet <p.psql@pinaraf.info>
Date: 2018-03-08T11:33:03Z
Lists: pgsql-hackers 
On Wed, Mar 7, 2018 at 3:49 PM, Thomas Munro
<thomas.munro@enterprisedb.com> wrote:
> make check at today's HEAD of your jit branch crashes on my FreeBSD
> box.  The first thing to crash is this query from point.sql:
>
> LOG:  server process (PID 87060) was terminated by signal 4: Illegal instruction
> DETAIL:  Failed process was running: SELECT '' AS thirtysix, p1.f1 AS
> point1, p2.f1 AS point2, p1.f1 <-> p2.f1 AS dist
>            FROM POINT_TBL p1, POINT_TBL p2
>            ORDER BY dist, p1.f1[0], p2.f1[0];

Hmm.  It's trying to execute an AVX instruction.

* thread #1, stop reason = breakpoint 1.1
    frame #0: llvmjit.so`ExecRunCompiledExpr(state=0x0000000801de4880,
econtext=0x0000000801de3560, isNull="") at llvmjit_expr.c:432
   429
   430          state->evalfunc = func;
   431
-> 432          return func(state, econtext, isNull);
   433  }
   434
   435  static void emit_lifetime_end(ExprState *state, LLVMModuleRef
mod, LLVMBuilderRef b);
(lldb) s
Process 44513 stopped
* thread #1, stop reason = signal SIGILL: privileged instruction
    frame #0: 0x0000000801157193
->  0x801157193: vmovsd (%rax), %xmm0             ; xmm0 = mem[0],zero
    0x801157197: vmovsd 0x8(%rax), %xmm1          ; xmm1 = mem[0],zero
    0x80115719c: vsubsd (%rcx), %xmm0, %xmm2
    0x8011571a0: vsubsd 0x8(%rcx), %xmm1, %xmm0
(lldb) bt
* thread #1, stop reason = signal SIGILL: privileged instruction
  * frame #0: 0x0000000801157193

This is running on a "Intel(R) Celeron(R) CPU G1610T @ 2.30GHz" with no AVX.

I am not sure if that is real though, because the stack is immediately
corrupted.  So either func is not really a function, or it is but was
compiled for the wrong target.  I see that you call
LLVMCreateTargetMachine() with the result of LLVMGetHostCPUName() as
cpu.  For me that's "ivybridge", so I tried hard coding "generic"
instead and it didn't help.  I see that you say "" for features, where
is where one would normally put "avx" to turn on AVX instructions, so
I think perhaps that theory is entirely bogus.

-- 
Thomas Munro
http://www.enterprisedb.com

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".