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author | Koichi Sasada <ko1@atdot.net> | 2021-11-13 02:12:20 +0900 |
---|---|---|
committer | Koichi Sasada <ko1@atdot.net> | 2021-11-15 15:58:56 +0900 |
commit | b1b73936c15fd490159a9b30ab50b8d5dfea1264 (patch) | |
tree | 23c8d640d3251ca0b3865087ae12b27941397d48 /tool/mk_builtin_loader.rb | |
parent | f9638c3b1716df4a94ea6ae0854cf55d66072ee4 (diff) |
`Primitive.mandatory_only?` for fast path
Compare with the C methods, A built-in methods written in Ruby is
slower if only mandatory parameters are given because it needs to
check the argumens and fill default values for optional and keyword
parameters (C methods can check the number of parameters with `argc`,
so there are no overhead). Passing mandatory arguments are common
(optional arguments are exceptional, in many cases) so it is important
to provide the fast path for such common cases.
`Primitive.mandatory_only?` is a special builtin function used with
`if` expression like that:
```ruby
def self.at(time, subsec = false, unit = :microsecond, in: nil)
if Primitive.mandatory_only?
Primitive.time_s_at1(time)
else
Primitive.time_s_at(time, subsec, unit, Primitive.arg!(:in))
end
end
```
and it makes two ISeq,
```
def self.at(time, subsec = false, unit = :microsecond, in: nil)
Primitive.time_s_at(time, subsec, unit, Primitive.arg!(:in))
end
def self.at(time)
Primitive.time_s_at1(time)
end
```
and (2) is pointed by (1). Note that `Primitive.mandatory_only?`
should be used only in a condition of an `if` statement and the
`if` statement should be equal to the methdo body (you can not
put any expression before and after the `if` statement).
A method entry with `mandatory_only?` (`Time.at` on the above case)
is marked as `iseq_overload`. When the method will be dispatch only
with mandatory arguments (`Time.at(0)` for example), make another
method entry with ISeq (2) as mandatory only method entry and it
will be cached in an inline method cache.
The idea is similar discussed in https://bugs.ruby-lang.org/issues/16254
but it only checks mandatory parameters or more, because many cases
only mandatory parameters are given. If we find other cases (optional
or keyword parameters are used frequently and it hurts performance),
we can extend the feature.
Notes
Notes:
Merged: https://github.com/ruby/ruby/pull/5112
Diffstat (limited to 'tool/mk_builtin_loader.rb')
-rw-r--r-- | tool/mk_builtin_loader.rb | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/tool/mk_builtin_loader.rb b/tool/mk_builtin_loader.rb index 6740ec5c17..02941735f7 100644 --- a/tool/mk_builtin_loader.rb +++ b/tool/mk_builtin_loader.rb @@ -100,6 +100,7 @@ def collect_builtin base, tree, name, bs, inlines, locals = nil when :call, :command_call # CALL _, recv, sep, mid, (_, args) = tree end + if mid raise "unknown sexp: #{mid.inspect}" unless %i[@ident @const].include?(mid.first) _, mid, (lineno,) = mid @@ -126,7 +127,7 @@ def collect_builtin base, tree, name, bs, inlines, locals = nil args.pop unless (args ||= []).last argc = args.size - if /(.+)\!\z/ =~ func_name + if /(.+)[\!\?]\z/ =~ func_name case $1 when 'attr' text = inline_text(argc, args.first) @@ -156,6 +157,8 @@ def collect_builtin base, tree, name, bs, inlines, locals = nil func_name = nil # required inlines[inlines.size] = [lineno, text, nil, nil] argc -= 1 + when 'mandatory_only' + func_name = nil when 'arg' argc == 1 or raise "unexpected argument number #{argc}" (arg = args.first)[0] == :symbol_literal or raise "symbol literal expected #{args}" |