Horton

Re: JIT compiling with LLVM v12

Pierre Ducroquet <p.psql@pinaraf.info>

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From: Pierre Ducroquet <p.psql@pinaraf.info>
To: pgsql-hackers@lists.postgresql.org, pgsql-hackers@postgresql.org
Date: 2018-03-29T15:03:08Z
Lists: pgsql-hackers 
On Thursday, March 29, 2018 2:39:17 PM CEST Jesper Pedersen wrote:
> Hi Andres,
> 
> On 03/28/2018 05:27 PM, Andres Freund wrote:
> > On 2018-03-27 10:34:26 -0700, Andres Freund wrote:
> >> On 2018-03-27 10:05:47 -0400, Peter Eisentraut wrote:
> >>> On 3/13/18 19:40, Andres Freund wrote:
> >>>> I've pushed a revised and rebased version of my JIT patchset.
> >>> 
> >>> What is the status of this item as far as the commitfest is concerned?
> >> 
> >> 7/10 committed. Inlining, Explain, Docs remain.
> > 
> > I've pushed these three.
> 
> It seems that clang is being picked up as the main compiler in certain
> situations, ala
> 
> ccache gcc -Wall -Wmissing-prototypes -Wpointer-arith
> -Wdeclaration-after-statement -Wendif-labels -Wmissing-format-attribute
> -Wformat-security -fno-strict-aliasing -fwrapv
> -fexcess-precision=standard -g -O0 -fno-omit-frame-pointer
> -I../../../src/include  -D_GNU_SOURCE -I/usr/include/libxml2   -c -o
> auth-scram.o auth-scram.c -MMD -MP -MF .deps/auth-scram.Po
> ccache gcc -Wall -Wmissing-prototypes -Wpointer-arith
> -Wdeclaration-after-statement -Wendif-labels -Wmissing-format-attribute
> -Wformat-security -fno-strict-aliasing -fwrapv
> -fexcess-precision=standard -g -O0 -fno-omit-frame-pointer
> -I../../../src/include  -D_GNU_SOURCE -I/usr/include/libxml2   -c -o
> be-secure-openssl.o be-secure-openssl.c -MMD -MP -MF
> .deps/be-secure-openssl.Po
> /usr/lib64/ccache/clang -Wno-ignored-attributes -fno-strict-aliasing
> -fwrapv -O2  -I../../../src/include  -D_GNU_SOURCE
> -I/usr/include/libxml2  -flto=thin -emit-llvm -c -o be-fsstubs.bc
> be-fsstubs.c
> /usr/lib64/ccache/clang -Wno-ignored-attributes -fno-strict-aliasing
> -fwrapv -O2  -I../../../src/include  -D_GNU_SOURCE
> -I/usr/include/libxml2  -flto=thin -emit-llvm -c -o namespace.bc namespace.c
> 
> I would expect LLVM to be isolated to the jit/ hierarchy.

Clang is needed to emit the LLVM bitcode required for inlining. The "-emit-
llvm" flag is used for that. A dual compilation is required for inlining to 
work, one compilation with gcc/clang/msvc/… to build the postgresql binary, 
one with clang to generate the .bc files for inlining.
It can be surprising, but there is little way around that (or we accept only 
clang to build postgresql, but there would be a riot).

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".