We face `[BUG] unexpected rb_parser_ary_data_type (0) for script lines`
on master branch recently.
This commit changes `enum rb_parser_ary_data_type` to start with `1`
and `0` to be invalid then it makes clear `rb_parser_ary_data_type (0)`
is not intentional.
This patch optimizes forwarding callers and callees. It only optimizes methods that only take `...` as their parameter, and then pass `...` to other calls.
Calls it optimizes look like this:
```ruby
def bar(a) = a
def foo(...) = bar(...) # optimized
foo(123)
```
```ruby
def bar(a) = a
def foo(...) = bar(1, 2, ...) # optimized
foo(123)
```
```ruby
def bar(*a) = a
def foo(...)
list = [1, 2]
bar(*list, ...) # optimized
end
foo(123)
```
All variants of the above but using `super` are also optimized, including a bare super like this:
```ruby
def foo(...)
super
end
```
This patch eliminates intermediate allocations made when calling methods that accept `...`.
We can observe allocation elimination like this:
```ruby
def m
x = GC.stat(:total_allocated_objects)
yield
GC.stat(:total_allocated_objects) - x
end
def bar(a) = a
def foo(...) = bar(...)
def test
m { foo(123) }
end
test
p test # allocates 1 object on master, but 0 objects with this patch
```
```ruby
def bar(a, b:) = a + b
def foo(...) = bar(...)
def test
m { foo(1, b: 2) }
end
test
p test # allocates 2 objects on master, but 0 objects with this patch
```
How does it work?
-----------------
This patch works by using a dynamic stack size when passing forwarded parameters to callees.
The caller's info object (known as the "CI") contains the stack size of the
parameters, so we pass the CI object itself as a parameter to the callee.
When forwarding parameters, the forwarding ISeq uses the caller's CI to determine how much stack to copy, then copies the caller's stack before calling the callee.
The CI at the forwarded call site is adjusted using information from the caller's CI.
I think this description is kind of confusing, so let's walk through an example with code.
```ruby
def delegatee(a, b) = a + b
def delegator(...)
delegatee(...) # CI2 (FORWARDING)
end
def caller
delegator(1, 2) # CI1 (argc: 2)
end
```
Before we call the delegator method, the stack looks like this:
```
Executing Line | Code | Stack
---------------+---------------------------------------+--------
1| def delegatee(a, b) = a + b | self
2| | 1
3| def delegator(...) | 2
4| # |
5| delegatee(...) # CI2 (FORWARDING) |
6| end |
7| |
8| def caller |
-> 9| delegator(1, 2) # CI1 (argc: 2) |
10| end |
```
The ISeq for `delegator` is tagged as "forwardable", so when `caller` calls in
to `delegator`, it writes `CI1` on to the stack as a local variable for the
`delegator` method. The `delegator` method has a special local called `...`
that holds the caller's CI object.
Here is the ISeq disasm fo `delegator`:
```
== disasm: #<ISeq:delegator@-e:1 (1,0)-(1,39)>
local table (size: 1, argc: 0 [opts: 0, rest: -1, post: 0, block: -1, kw: -1@-1, kwrest: -1])
[ 1] "..."@0
0000 putself ( 1)[LiCa]
0001 getlocal_WC_0 "..."@0
0003 send <calldata!mid:delegatee, argc:0, FCALL|FORWARDING>, nil
0006 leave [Re]
```
The local called `...` will contain the caller's CI: CI1.
Here is the stack when we enter `delegator`:
```
Executing Line | Code | Stack
---------------+---------------------------------------+--------
1| def delegatee(a, b) = a + b | self
2| | 1
3| def delegator(...) | 2
-> 4| # | CI1 (argc: 2)
5| delegatee(...) # CI2 (FORWARDING) | cref_or_me
6| end | specval
7| | type
8| def caller |
9| delegator(1, 2) # CI1 (argc: 2) |
10| end |
```
The CI at `delegatee` on line 5 is tagged as "FORWARDING", so it knows to
memcopy the caller's stack before calling `delegatee`. In this case, it will
memcopy self, 1, and 2 to the stack before calling `delegatee`. It knows how much
memory to copy from the caller because `CI1` contains stack size information
(argc: 2).
Before executing the `send` instruction, we push `...` on the stack. The
`send` instruction pops `...`, and because it is tagged with `FORWARDING`, it
knows to memcopy (using the information in the CI it just popped):
```
== disasm: #<ISeq:delegator@-e:1 (1,0)-(1,39)>
local table (size: 1, argc: 0 [opts: 0, rest: -1, post: 0, block: -1, kw: -1@-1, kwrest: -1])
[ 1] "..."@0
0000 putself ( 1)[LiCa]
0001 getlocal_WC_0 "..."@0
0003 send <calldata!mid:delegatee, argc:0, FCALL|FORWARDING>, nil
0006 leave [Re]
```
Instruction 001 puts the caller's CI on the stack. `send` is tagged with
FORWARDING, so it reads the CI and _copies_ the callers stack to this stack:
```
Executing Line | Code | Stack
---------------+---------------------------------------+--------
1| def delegatee(a, b) = a + b | self
2| | 1
3| def delegator(...) | 2
4| # | CI1 (argc: 2)
-> 5| delegatee(...) # CI2 (FORWARDING) | cref_or_me
6| end | specval
7| | type
8| def caller | self
9| delegator(1, 2) # CI1 (argc: 2) | 1
10| end | 2
```
The "FORWARDING" call site combines information from CI1 with CI2 in order
to support passing other values in addition to the `...` value, as well as
perfectly forward splat args, kwargs, etc.
Since we're able to copy the stack from `caller` in to `delegator`'s stack, we
can avoid allocating objects.
I want to do this to eliminate object allocations for delegate methods.
My long term goal is to implement `Class#new` in Ruby and it uses `...`.
I was able to implement `Class#new` in Ruby
[here](https://github.com/ruby/ruby/pull/9289).
If we adopt the technique in this patch, then we can optimize allocating
objects that take keyword parameters for `initialize`.
For example, this code will allocate 2 objects: one for `SomeObject`, and one
for the kwargs:
```ruby
SomeObject.new(foo: 1)
```
If we combine this technique, plus implement `Class#new` in Ruby, then we can
reduce allocations for this common operation.
Co-Authored-By: John Hawthorn <john@hawthorn.email>
Co-Authored-By: Alan Wu <XrXr@users.noreply.github.com>
Recently, `TestRubyLiteral#test_float` fails randomly.
```
1) Error:
TestRubyLiteral#test_float:
ArgumentError: SyntaxError#path changed: "(eval at /home/chkbuild/chkbuild/tmp/build/20240527T050036Z/ruby/test/ruby/test_literal.rb:642)"->"(eval at /home/chkbuild/chkbuild/tmp/build/20240527T050036Z/ruby/test/ruby/test_literal.rb:642)"
```
https://rubyci.s3.amazonaws.com/s390x/ruby-master/log/20240527T050036Z.fail.html.gz
According to Launchable, the first failure was on Apr 30.
This is just when 528c4501f4 was
committed. I don't know if the change is really the cause, but I want to
revert it once to see if the random failure disappears.
I think this fixes the following random test failure that could not be
fixed for a long time:
```
1) Failure:
TestSymbol#test_inspect_under_gc_compact_stress [/home/chkbuild/chkbuild/tmp/build/20240522T003003Z/ruby/test/ruby/test_symbol.rb:126]:
<":testing"> expected but was
<":\"\\x00\\x00\\x00\\x00\\x00\\x00\\x00\"">.
```
The value passed to this function is the return value of `rb_id2str`, so
it is never collected. However, if auto_compact is enabled, the string
may move and `RSTRING_PTR(str)` became invalid.
This change prevents the string from being moved by RB_GC_GUARD.
* Add types to `tLAMBDA` and `tSTRING_DBEG` to store corresponding
information when returning these tokens.
* Add `enum lex_state_e state` to `%union` for `tSTRING_DBEG`.
In the past, these codes were used by both parser and ripper.
On ripper, the type of LHS is `<val>` then type cast was needed.
However currently these are only used by parser then no need to
cast.
rb_ast_dispose does not free the rb_ast_t causing it to be leaked. This
commit changes it to use rb_ast_free instead.
For example:
require "ripper"
10.times do
100_000.times do
Ripper.sexp("")
end
puts `ps -o rss= -p #{$$}`
end
Before:
27648
32512
37376
42240
47232
52224
57344
62208
67072
71936
After:
22784
22784
22784
22784
22912
22912
22912
22912
22912
22912
yui-knk
Nobuyoshi Nakada
Aaron Patterson
S-H-GAMELINKS
Kevin Newton
Jeremy Evans
Yusuke Endoh
ydah
Peter Zhu