In December 2021, we opened an [issue] to solicit feedback regarding the
porting of the YJIT codebase from C99 to Rust. There were some
reservations, but this project was given the go ahead by Ruby core
developers and Matz. Since then, we have successfully completed the port
of YJIT to Rust.
The new Rust version of YJIT has reached parity with the C version, in
that it passes all the CRuby tests, is able to run all of the YJIT
benchmarks, and performs similarly to the C version (because it works
the same way and largely generates the same machine code). We've even
incorporated some design improvements, such as a more fine-grained
constant invalidation mechanism which we expect will make a big
difference in Ruby on Rails applications.
Because we want to be careful, YJIT is guarded behind a configure
option:
```shell
./configure --enable-yjit # Build YJIT in release mode
./configure --enable-yjit=dev # Build YJIT in dev/debug mode
```
By default, YJIT does not get compiled and cargo/rustc is not required.
If YJIT is built in dev mode, then `cargo` is used to fetch development
dependencies, but when building in release, `cargo` is not required,
only `rustc`. At the moment YJIT requires Rust 1.60.0 or newer.
The YJIT command-line options remain mostly unchanged, and more details
about the build process are documented in `doc/yjit/yjit.md`.
The CI tests have been updated and do not take any more resources than
before.
The development history of the Rust port is available at the following
commit for interested parties:
1fd9573d8b
Our hope is that Rust YJIT will be compiled and included as a part of
system packages and compiled binaries of the Ruby 3.2 release. We do not
anticipate any major problems as Rust is well supported on every
platform which YJIT supports, but to make sure that this process works
smoothly, we would like to reach out to those who take care of building
systems packages before the 3.2 release is shipped and resolve any
issues that may come up.
[issue]: https://bugs.ruby-lang.org/issues/18481
Co-authored-by: Maxime Chevalier-Boisvert <maximechevalierb@gmail.com>
Co-authored-by: Noah Gibbs <the.codefolio.guy@gmail.com>
Co-authored-by: Kevin Newton <kddnewton@gmail.com>
Add an empty line before the module doc string so RDoc can find it.
While we are at it, edit for clarity. The file should already be
using frozen string literals since c10d5085a2.
[ci skip]
Previously, YJIT crashes with rb_bug() when asked to compile new methods
while out of executable memory.
To handle this situation gracefully, this change keeps track of all the
blocks compiled each invocation in case YJIT runs out of memory in the
middle of a compliation sequence. The list is used to free all blocks in
case compilation fails.
yjit_gen_block() is renamed to gen_single_block() to make it distinct from
gen_block_version(). Call to limit_block_version() and block_t
allocation is moved into the function to help tidy error checking in the
outer loop.
limit_block_version() now returns by value. I feel that an out parameter
with conditional mutation is unnecessarily hard to read in code that
does not need to go for last drop performance. There is a good chance
that the optimizer is able to output identical code anyways.
This commit adds an entry_exit field to block_t for use in
invalidate_block_version(). By patching the start of the block while
invalidating it, invalidate_block_version() can function correctly
while there is no executable memory left for new branch stubs.
This change additionally fixes correctness for situations where we
cannot patch incoming jumps to the invalidated block. In situations
such as Shopify/yjit#226, the address to the start of the block
is saved and used later, possibly after the block is invalidated.
The assume_* family of function now generate block->entry_exit before
remembering blocks for invalidation.
RubyVM::YJIT.simulate_oom! is introduced for testing out of memory
conditions. The test for it is disabled for now because OOM triggers
other failure conditions not addressed by this commit.
FixesShopify/yjit#226
This change fixes `-v --yjit-stats`. Previously in this situation,
YJIT._print_stats wasn't defined as yjit.rb is not evaluated when there
is only "-v" and no Ruby code to run.
In an effort to minimize build issues on non x64 platforms, we can
decide at build time to not build the bulk of YJIT. This should fix
obscure build errors like this one on riscv64:
yjit_asm.c:137:(.text+0x3fa): relocation truncated to fit: R_RISCV_PCREL_HI20 against `alloc_exec_mem'
We also don't need to bulid YJIT on `--disable-jit-support` builds.
One wrinkle to this is that the YJIT Ruby module will not be defined
when YJIT is stripped from the build. I think that's a fair change as
it's only meant to be used for YJIT development.
Before this change, when we encounter a constant cache that is specific
to a lexical scope, we unconditionally exit. This change falls back to
the interpreter's cache in this situation.
This should help constant expressions in `class << self`, which is popular
at Shopify due to the style guide.
This change relies on the cache being warm while compiling to detect the
need for checking the lexical scope for simplicity.
We weren't counting completing an entire method in YJIT as exits so the
avg_len_in_yjit for
./miniruby --yjit-call-threshold=1 --yjit-stats -e'def foo; end; foo'
was infinite.
For use cases where you want to collect the metrics
for a specific piece of code (typically a web request)
you can have the stats turned off by default and then
turn them on at runtime before executing the code you care
about.
This adds a method to blocks to get outgoing ids, then uses the outgoing
ids to generate a graphviz graph. Two methods were added to the Block
object. One method returns an id for the block, which is just the
address of the underlying block. The other method returns a list of
outgoing block ids. We can use Block#id in conjunction with
Block#outgoing_ids to construct a graph of blocks
* Implement send with blocks
Not that much extra work compared to `opt_send_without_block`.
Moved the stack over flow check because it could've exited after changes
are made to cfp.
* rename oswb counters
* Might as well implement sending block to cfuncs
* Disable sending blocks to cfuncs for now
* Reconstruct interpreter sp before calling into cfuncs
In case the callee cfunc calls a method or delegates to a block.
This also has the side benefit of letting call sites that sometimes are
iseq calls and sometimes cfunc call share the same successor.
* only sync with interpreter sp when passing a block
Co-authored-by: Maxime Chevalier-Boisvert <maximechevalierb@gmail.com>
Co-authored-by: Aaron Patterson <aaron.patterson@shopify.com>
Introduce a new macro `ADD_COMMENT(cb, comment)` that records a comment
for the current write position in the code block.
Co-authored-by: Maxime Chevalier-Boisvert <maximechevalierb@gmail.com>
Co-authored-by: Aaron Patterson <aaron.patterson@shopify.com>
Lazily compile out a chain of checks for different known classes and
whether `self` embeds its ivars or not.
* Remove trailing whitespaces
* Get proper addresss in Capstone disassembly
* Lowercase address in Capstone disassembly
Capstone uses lowercase for jump targets in generated listings. Let's
match it.
* Use the same successor in getivar guard chains
Cuts down on duplication
* Address reviews
* Fix copypasta error
* Add a comment
Alan Wu
Nobuyoshi Nakada
Alan Wu
Maxime Chevalier-Boisvert
John Hawthorn
Jean Boussier
Maxime Chevalier-Boisvert
Aaron Patterson
Kevin Deisz
Noah Gibbs
Jose Narvaez