annotate the signature type of the first argument of kwcall method

[aviatesk]

This commit annotates the signature type of the first argument of kwcall method as kwargs::NamedTuple.
Previously it's annotated as ::Any but only NamedTuple object is supported (and synthesized by the frontend) as the first argument to kwcall method.

[vtjnash]

Did you check performance and memory use of this? There are optimized dispatch lookup tables for Any that do not exist for NamedTuples.

[aviatesk]

I used this script:

global inline_checker = x -> x + 1

function call_kwfunc_itr(kwfunc, arg, itr)
    local r = 0
    r += kwfunc(arg; kw=itr[1])
    r += kwfunc(arg; kw=itr[2])
    r += kwfunc(arg; kw=itr[3])
    r += kwfunc(arg; kw=itr[4])
    r += kwfunc(arg; kw=itr[5])
    r
end

function simple_kwfunc(a; kw=nothing)
    c = isa(kw, Function)
    inline_checker(c) # cause dynamic dispatch to prevent inlining
end

function simple_kwfunc_nospec(a; @nospecialize kw=nothing)
    c = isa(kw, Function)
    inline_checker(c) # cause dynamic dispatch to prevent inlining
end

function simple_kwfunc_kws(a; kws...)
    c = isa(kws[1], Function)
    inline_checker(c) # cause dynamic dispatch to prevent inlining
end

dynamic_itr = Any[sin, muladd, "foo", nothing, missing]   # untyped container can cause excessive runtime dispatch

using BenchmarkTools

call_kwfunc_itr(simple_kwfunc, 1, dynamic_itr)
call_kwfunc_itr(simple_kwfunc_nospec, 1, dynamic_itr)
call_kwfunc_itr(simple_kwfunc_kws, 1, dynamic_itr)

@benchmark call_kwfunc_itr(simple_kwfunc, 1, dynamic_itr)
@benchmark call_kwfunc_itr(simple_kwfunc_nospec, 1, dynamic_itr)
@benchmark call_kwfunc_itr(simple_kwfunc_kws, 1, dynamic_itr)

And there does not seem to be no big difference?

the previous commit (57b68f2)

julia> @benchmark call_kwfunc_itr(simple_kwfunc, 1, dynamic_itr)
BenchmarkTools.Trial: 10000 samples with 187 evaluations.
 Range (min … max):  555.706 ns …  3.315 μs  ┊ GC (min … max): 0.00% … 78.52%
 Time  (median):     582.219 ns              ┊ GC (median):    0.00%
 Time  (mean ± σ):   591.227 ns ± 35.978 ns  ┊ GC (mean ± σ):  0.04% ±  0.79%

           ▁▆█▄                                                 
  ▁▁▁▁▂▁▂▄▇████▆▅▅▄▄▃▃▃▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁ ▂
  556 ns          Histogram: frequency by time          686 ns <

 Memory estimate: 32 bytes, allocs estimate: 2.

julia> @benchmark call_kwfunc_itr(simple_kwfunc_nospec, 1, dynamic_itr)
BenchmarkTools.Trial: 10000 samples with 379 evaluations.
 Range (min … max):  248.459 ns … 537.158 ns  ┊ GC (min … max): 0.00% … 0.00%
 Time  (median):     257.037 ns               ┊ GC (median):    0.00%
 Time  (mean ± σ):   258.401 ns ±  11.020 ns  ┊ GC (mean ± σ):  0.00% ± 0.00%

  ▁▇▆      ▇█▄▂       ▂▁       ▁▁▁▁▁▁                           ▂
  ████▃▃▅▅▄█████▇▇▇▇▇▇███▇██▇▆▆███████▇▇▇▆▇█▇▇▇▇▇▇▆▆▆▆▆▇▅▅▄▆▅▄▅ █
  248 ns        Histogram: log(frequency) by time        300 ns <

 Memory estimate: 0 bytes, allocs estimate: 0.

julia> @benchmark call_kwfunc_itr(simple_kwfunc_kws, 1, dynamic_itr)
BenchmarkTools.Trial: 10000 samples with 185 evaluations.
 Range (min … max):  556.081 ns …  4.121 μs  ┊ GC (min … max): 0.00% … 78.95%
 Time  (median):     583.335 ns              ┊ GC (median):    0.00%
 Time  (mean ± σ):   591.977 ns ± 41.955 ns  ┊ GC (mean ± σ):  0.05% ±  0.79%

           ▅▇█▇▅▂                                               
  ▁▁▁▁▁▁▁▃▇███████▇▆▅▄▃▃▃▃▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▁▁▂▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁ ▂
  556 ns          Histogram: frequency by time          677 ns <

 Memory estimate: 32 bytes, allocs estimate: 2.

this PR (357bcdd)

julia> @benchmark call_kwfunc_itr(simple_kwfunc, 1, dynamic_itr)
BenchmarkTools.Trial: 10000 samples with 187 evaluations.
 Range (min … max):  550.134 ns …  3.294 μs  ┊ GC (min … max): 0.00% … 78.85%
 Time  (median):     572.861 ns              ┊ GC (median):    0.00%
 Time  (mean ± σ):   585.157 ns ± 38.791 ns  ┊ GC (mean ± σ):  0.04% ±  0.79%

   ▁▁  ▁▅██▇▅▅▅▄▄▄▄▃▂▁▂▁▂▂▂▂▁▁▁▁▂▂▂▁▁▁▁ ▁                      ▂
  ▇███▆█████████████████████████████████████▇▇▇█▇█▆▇▇▇▅▆▆▆▅▆▆▅ █
  550 ns        Histogram: log(frequency) by time       694 ns <

 Memory estimate: 32 bytes, allocs estimate: 2.

julia> @benchmark call_kwfunc_itr(simple_kwfunc_nospec, 1, dynamic_itr)
BenchmarkTools.Trial: 10000 samples with 355 evaluations.
 Range (min … max):  256.456 ns …  3.609 μs  ┊ GC (min … max): 0.00% … 0.00%
 Time  (median):     259.507 ns              ┊ GC (median):    0.00%
 Time  (mean ± σ):   268.259 ns ± 38.205 ns  ┊ GC (mean ± σ):  0.00% ± 0.00%

   ▇█▃     ▅▆▃▂▂    ▁▃▃▃▂▂▁▁ ▁▁▁▁▂▁▁                           ▂
  ▇███▆▇▇▆████████▇█████████████████▇█████▇█▇▆▆▆▆▆▇▆▆▆▄▆▅▅▅▄▅▅ █
  256 ns        Histogram: log(frequency) by time       318 ns <

 Memory estimate: 0 bytes, allocs estimate: 0.

julia> @benchmark call_kwfunc_itr(simple_kwfunc_kws, 1, dynamic_itr)
BenchmarkTools.Trial: 10000 samples with 187 evaluations.
 Range (min … max):  551.021 ns …  3.627 μs  ┊ GC (min … max): 0.00% … 80.38%
 Time  (median):     580.658 ns              ┊ GC (median):    0.00%
 Time  (mean ± σ):   592.102 ns ± 40.868 ns  ┊ GC (mean ± σ):  0.05% ±  0.80%

     ▁▂▂ ▂▅▇██▇▆▅▅▅▅▄▄▄▃▂▂▃▃▃▃▂▂▂▁▂▂▂▂▁▁▁▁▁▁ ▁                 ▂
  ▄▇████████████████████████████████████████████▇▇▇█▇▇▇▆█▆▆▆▆▇ █
  551 ns        Histogram: log(frequency) by time       695 ns <

 Memory estimate: 32 bytes, allocs estimate: 2.