Instead using memset to set tts_isnull, call the new
slot_getmissingattrs().
Also fix a bug (= instead of >=) in the code generation. Normally = is
correct, but when repeatedly deforming fields not in a
tuple (e.g. deform up to natts + 1 and then natts + 2) >= is needed.
Discussion: https://postgr.es/m/20180328010053.i2qvsuuusst4lgmc@alap3.anarazel.de
Performing JIT compilation for deforming gains performance benefits
over unJITed deforming from compile-time knowledge of the tuple
descriptor. Fixed column widths, NOT NULLness, etc can be taken
advantage of.
Right now the JITed deforming is only used when deforming tuples as
part of expression evaluation (and obviously only if the descriptor is
known). It's likely to be beneficial in other cases, too.
By default tuple deforming is JITed whenever an expression is JIT
compiled. There's a separate boolean GUC controlling it, but that's
expected to be primarily useful for development and benchmarking.
Docs will follow in a later commit containing docs for the whole JIT
feature.
Author: Andres Freund
Discussion: https://postgr.es/m/20170901064131.tazjxwus3k2w3ybh@alap3.anarazel.de
The LLVM JIT provider uses clang to synchronize types between normal C
code and runtime generated code. Clang represents stdbool.h style
booleans in return values & parameters differently from booleans
stored in variables.
Thus the expression compilation code from 2a0faed9d needs to be
adapted to 9a95a77d9. Instead of hardcoding i8 as the type for
booleans (which already was wrong on some edge case platforms!), use
postgres' notion of a boolean as used for storage and for parameters.
Per buildfarm animal xenodermus.
Author: Andres Freund
This commit introduces the ability to actually generate code using
LLVM. In particular, this adds:
- Ability to emit code both in heavily optimized and largely
unoptimized fashion
- Batching facility to allow functions to be defined in small
increments, but optimized and emitted in executable form in larger
batches (for performance and memory efficiency)
- Type and function declaration synchronization between runtime
generated code and normal postgres code. This is critical to be able
to access struct fields etc.
- Developer oriented jit_dump_bitcode GUC, for inspecting / debugging
the generated code.
- per JitContext statistics of number of functions, time spent
generating code, optimizing, and emitting it. This will later be
employed for EXPLAIN support.
This commit doesn't yet contain any code actually generating
functions. That'll follow in later commits.
Documentation for GUCs added, and for JIT in general, will be added in
later commits.
Author: Andres Freund, with contributions by Pierre Ducroquet
Testing-By: Thomas Munro, Peter Eisentraut
Discussion: https://postgr.es/m/20170901064131.tazjxwus3k2w3ybh@alap3.anarazel.de
Alexander Korotkov
Andres Freund