Now that we have a `set_table` implementation, we can
use it to track const caches and save some memory.
We could even save some more memory if `numtable` didn't
store a copy of the `hash` and instead recomputed it every
time, but this is a quick win.
Set has been an autoloaded standard library since Ruby 3.2.
The standard library Set is less efficient than it could be, as it
uses Hash for storage, which stores unnecessary values for each key.
Implementation details:
* Core Set uses a modified version of `st_table`, named `set_table`.
than `s/st_/set_/`, the main difference is that the stored records
do not have values, making them 1/3 smaller. `st_table_entry` stores
`hash`, `key`, and `record` (value), while `set_table_entry` only
stores `hash` and `key`. This results in large sets using ~33% less
memory compared to stdlib Set. For small sets, core Set uses 12% more
memory (160 byte object slot and 64 malloc bytes, while stdlib set
uses 40 for Set and 160 for Hash). More memory is used because
the set_table is embedded and 72 bytes in the object slot are
currently wasted. Hopefully we can make this more efficient and have
it stored in an 80 byte object slot in the future.
* All methods are implemented as cfuncs, except the pretty_print
methods, which were moved to `lib/pp.rb` (which is where the
pretty_print methods for other core classes are defined). As is
typical for core classes, internal calls call C functions and
not Ruby methods. For example, to check if something is a Set,
`rb_obj_is_kind_of` is used, instead of calling `is_a?(Set)` on the
related object.
* Almost all methods use the same algorithm that the pure-Ruby
implementation used. The exception is when calling `Set#divide` with a
block with 2-arity. The pure-Ruby method used tsort to implement this.
I developed an algorithm that only allocates a single intermediate
hash and does not need tsort.
* The `flatten_merge` protected method is no longer necessary, so it
is not implemented (it could be).
* Similar to Hash/Array, subclasses of Set are no longer reflected in
`inspect` output.
* RDoc from stdlib Set was moved to core Set, with minor updates.
This includes a comprehensive benchmark suite for all public Set
methods. As you would expect, the native version is faster in the
vast majority of cases, and multiple times faster in many cases.
There are a few cases where it is significantly slower:
* Set.new with no arguments (~1.6x)
* Set#compare_by_identity for small sets (~1.3x)
* Set#clone for small sets (~1.5x)
* Set#dup for small sets (~1.7x)
These are slower as Set does not currently use the AR table
optimization that Hash does, so a new set_table is initialized for
each call. I'm not sure it's worth the complexity to have an AR
table-like optimization for small sets (for hashes it makes sense,
as small hashes are used everywhere in Ruby).
The rbs and repl_type_completor bundled gems will need updates to
support core Set. The pull request marks them as allowed failures.
This passes all set tests with no changes. The following specs
needed modification:
* Modifying frozen set error message (changed for the better)
* `Set#divide` when passed a 2-arity block no longer yields the same
object as both the first and second argument (this seems like an issue
with the previous implementation).
* Set-like objects that override `is_a?` such that `is_a?(Set)` return
`true` are no longer treated as Set instances.
* `Set.allocate.hash` is no longer the same as `nil.hash`
* `Set#join` no longer calls `Set#to_a` (it calls the underlying C
function).
* `Set#flatten_merge` protected method is not implemented.
Previously, `set.rb` added a `SortedSet` autoload, which loads
`set/sorted_set.rb`. This replaces the `Set` autoload in `prelude.rb`
with a `SortedSet` autoload, but I recommend removing it and
`set/sorted_set.rb`.
This moves `test/set/test_set.rb` to `test/ruby/test_set.rb`,
reflecting that switch to a core class. This does not move the spec
files, as I'm not sure how they should be handled.
Internally, this uses the st_* types and functions as much as
possible, and only adds set_* types and functions as needed.
The underlying set_table implementation is stored in st.c, but
there is no public C-API for it, nor is there one planned, in
order to keep the ability to change the internals going forward.
For internal uses of st_table with Qtrue values, those can
probably be replaced with set_table. To do that, include
internal/set_table.h. To handle symbol visibility (rb_ prefix),
internal/set_table.h uses the same macro approach that
include/ruby/st.h uses.
The Set class (rb_cSet) and all methods are defined in set.c.
There isn't currently a C-API for the Set class, though C-API
functions can be added as needed going forward.
Implements [Feature #21216]
Co-authored-by: Jean Boussier <jean.boussier@gmail.com>
Co-authored-by: Oliver Nutter <mrnoname1000@riseup.net>
* Assert everything is compiled in test_zjit
* Update a comment on rb_zjit_assert_compiles
Co-authored-by: Maxime Chevalier-Boisvert <maxime.chevalierboisvert@shopify.com>
* Add a comment about assert_compiles
* Actually use pipe_fd
---------
Co-authored-by: Maxime Chevalier-Boisvert <maxime.chevalierboisvert@shopify.com>
* Add zjit_* instructions to profile the interpreter
* Rename FixnumPlus to FixnumAdd
* Update a comment about Invalidate
* Rename Guard to GuardType
* Rename Invalidate to PatchPoint
* Drop unneeded debug!()
* Plan on profiling the types
* Use the output of GuardType as type refined outputs
[Bug #20271]
[Bug #20267]
[Bug #20255]
`rb_obj_alloc(RBASIC_CLASS(obj))` will always allocate from the basic
40B pool, so if `obj` is larger than `40B`, we'll create a corrupted
object when we later copy the shape_id.
Instead we can use the same logic than ractor copy, which is
to use `rb_obj_clone`, and later ask the GC to free the original
object.
We then must turn it into a `T_OBJECT`, because otherwise
just changing its class to `RactorMoved` leaves a lot of
ways to keep using the object, e.g.:
```
a = [1, 2, 3]
Ractor.new{}.send(a, move: true)
[].concat(a) # Should raise, but wasn't.
```
If it turns out that `rb_obj_clone` isn't performant enough
for some uses, we can always have carefully crafted specialized
paths for the types that would benefit from it.
[Bug #21170]
st_table reserves -1 as a special hash value to indicate that an entry
has been deleted. So that that's a valid value to be returned from the
hash function, do_hash replaces -1 with 0 so that it is not mistaken for
the sentinel.
Previously, when upgrading an AR table to an ST table,
rb_st_add_direct_with_hash was used which did not perform the same
conversion, this could lead to a hash in a broken state where one if its
entries which was supposed to exist being marked as a tombstone.
The hash could then become further corrupted when the ST table required
resizing as the falsely tombstoned entry would be skipped but it would
be counted in num entries, leading to an uninitialized entry at index
15.
In most cases this will be really rare, unless using a very poorly
implemented custom hash function.
This also adds two debug assertions, one that st_add_direct_with_hash
does not receive the reserved hash value, and a second in
rebuild_table_with, which ensures that after we rebuild/compact a table
it contains the expected number of elements.
Co-authored-by: Alan Wu <alanwu@ruby-lang.org>
If the provided Hash doesn't have a default proc, we know for
sure that we'll never call into user provided code, hence the
string we allocate to access the Hash can't possibly escape.
So we don't actually have to allocate it, we can use a fake_str,
AKA a stack allocated string.
```
compare-ruby: ruby 3.5.0dev (2025-02-10T13:47:44Z master 3fb455adab) +PRISM [arm64-darwin23]
built-ruby: ruby 3.5.0dev (2025-02-10T17:09:52Z opt-gsub-alloc ea5c28958f) +PRISM [arm64-darwin23]
warming up....
| |compare-ruby|built-ruby|
|:----------------|-----------:|---------:|
|escape | 3.374k| 3.722k|
| | -| 1.10x|
|escape_bin | 5.469k| 6.587k|
| | -| 1.20x|
|escape_utf8 | 3.465k| 3.734k|
| | -| 1.08x|
|escape_utf8_bin | 5.752k| 7.283k|
| | -| 1.27x|
```
The macro provided by symbol.h uses STATIC_ID2SYM
when it can which speeds up methods that declare keyword args.
Co-authored-by: Alan Wu <XrXr@users.noreply.github.com>
Co-authored-by: Takashi Kokubun (k0kubun) <takashikkbn@gmail.com>
Co-authored-by: Maxime Chevalier-Boisvert <maxime.chevalierboisvert@shopify.com>
Co-authored-by: Aaron Patterson <tenderlove@ruby-lang.org>
We have name fragmentation for this feature, including "shared GC",
"modular GC", and "external GC". This commit standardizes the feature
name to "modular GC" and the implementation to "GC library".
