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>
`rb_id_table_lookup()` writes to a `VALUE`, which is definitely a distinct
type from `st_table *`. With LTO, the compiler is allowed by N1256
§6.5p7 to remove the output parameter write via type-based alias
analysis.
See also: a0a8f2abf5
This commit reintroduces finer-grained constant cache invalidation.
After 8008fb7 got merged, it was causing issues on token-threaded
builds (such as on Windows).
The issue was that when you're iterating through instruction sequences
and using the translator functions to get back the instruction structs,
you're either using `rb_vm_insn_null_translator` or
`rb_vm_insn_addr2insn2` depending if it's a direct-threading build.
`rb_vm_insn_addr2insn2` does some normalization to always return to
you the non-trace version of whatever instruction you're looking at.
`rb_vm_insn_null_translator` does not do that normalization.
This means that when you're looping through the instructions if you're
trying to do an opcode comparison, it can change depending on the type
of threading that you're using. This can be very confusing. So, this
commit creates a new translator function
`rb_vm_insn_normalizing_translator` to always return the non-trace
version so that opcode comparisons don't have to worry about different
configurations.
[Feature #18589]
This reverts commits for [Feature #18589]:
* 8008fb7352
"Update formatting per feedback"
* 8f6eaca2e1
"Delete ID from constant cache table if it becomes empty on ISEQ free"
* 629908586b
"Finer-grained inline constant cache invalidation"
MSWin builds on AppVeyor have been crashing since the merger.
Current behavior - caches depend on a global counter. All constant mutations cause caches to be invalidated.
```ruby
class A
B = 1
end
def foo
A::B # inline cache depends on global counter
end
foo # populate inline cache
foo # hit inline cache
C = 1 # global counter increments, all caches are invalidated
foo # misses inline cache due to `C = 1`
```
Proposed behavior - caches depend on name components. Only constant mutations with corresponding names will invalidate the cache.
```ruby
class A
B = 1
end
def foo
A::B # inline cache depends constants named "A" and "B"
end
foo # populate inline cache
foo # hit inline cache
C = 1 # caches that depend on the name "C" are invalidated
foo # hits inline cache because IC only depends on "A" and "B"
```
Examples of breaking the new cache:
```ruby
module C
# Breaks `foo` cache because "A" constant is set and the cache in foo depends
# on "A" and "B"
class A; end
end
B = 1
```
We expect the new cache scheme to be invalidated less often because names aren't frequently reused. With the cache being invalidated less, we can rely on its stability more to keep our constant references fast and reduce the need to throw away generated code in YJIT.
Use ISEQ_BODY macro to get the rb_iseq_constant_body of the ISeq. Using
this macro will make it easier for us to change the allocation strategy
of rb_iseq_constant_body when using Variable Width Allocation.
This change eagerly performs a bitwise and on the parameters. If both
parameters are fixnums, then the result value should also be a fixnum.
We can just test the bit on the result and return if it's a fixnum.
Otherwise return Qundef.
This commit removes the need to increment and decrement the indexes
used by vm_cc_attr_index getters and setters. It also introduces a
vm_cc_attr_index_p predicate function, and a vm_cc_attr_index_initalize
function.
`def` (`rb_method_definition_t`) is shared by multiple callable
method entries (cme, `rb_callable_method_entry_t`).
There are two issues:
* old -> young reference: `cme1->def->mandatory_only_cme = monly_cme`
if `cme1` is young and `monly_cme` is young, there is no problem.
Howevr, another old `cme2` can refer `def`, in this case, old `cme2`
points young `monly_cme` and it violates gengc assumption.
* cme can have different `defined_class` but `monly_cme` only has
one `defined_class`. It does not make sense and `monly_cme`
should be created for a cme (not `def`).
To solve these issues, this patch allocates `monly_cme` per `cme`.
`cme` does not have another room to store a pointer to the `monly_cme`,
so this patch introduces `overloaded_cme_table`, which is weak key map
`[cme] -> [monly_cme]`.
`def::body::iseqptr::monly_cme` is deleted.
The first issue is reported by Alan Wu.
* Lazily create singletons on instance_{exec,eval}
Previously when instance_exec or instance_eval was called on an object,
that object would be given a singleton class so that method
definitions inside the block would be added to the object rather than
its class.
This commit aims to improve performance by delaying the creation of the
singleton class unless/until one is needed for method definition. Most
of the time instance_eval is used without any method definition.
This was implemented by adding a flag to the cref indicating that it
represents a singleton of the object rather than a class itself. In this
case CREF_CLASS returns the object's existing class, but in cases that
we are defining a method (either via definemethod or
VM_SPECIAL_OBJECT_CBASE which is used for undef and alias).
This also happens to fix what I believe is a bug. Previously
instance_eval behaved differently with regards to constant access for
true/false/nil than for all other objects. I don't think this was
intentional.
String::Foo = "foo"
"".instance_eval("Foo") # => "foo"
Integer::Foo = "foo"
123.instance_eval("Foo") # => "foo"
TrueClass::Foo = "foo"
true.instance_eval("Foo") # NameError: uninitialized constant Foo
This also slightly changes the error message when trying to define a method
through instance_eval on an object which can't have a singleton class.
Before:
$ ruby -e '123.instance_eval { def foo; end }'
-e:1:in `block in <main>': no class/module to add method (TypeError)
After:
$ ./ruby -e '123.instance_eval { def foo; end }'
-e:1:in `block in <main>': can't define singleton (TypeError)
IMO this error is a small improvement on the original and better matches
the (both old and new) message when definging a method using `def self.`
$ ruby -e '123.instance_eval{ def self.foo; end }'
-e:1:in `block in <main>': can't define singleton (TypeError)
Co-authored-by: Matthew Draper <matthew@trebex.net>
* Remove "under" argument from yield_under
* Move CREF_SINGLETON_SET into vm_cref_new
* Simplify vm_get_const_base
* Fix leaf VM_SPECIAL_OBJECT_CONST_BASE
Co-authored-by: Matthew Draper <matthew@trebex.net>
The main impetus for this change is to fix [Bug #13392]. Previously, we
fired the "return" TracePoint event after popping the stack frame for
the block running as method (BMETHOD). This gave undesirable source
location outputs as the return event normally fires right before the
frame going away.
The iseq for each block can run both as a block and as a method. To
accommodate that, this commit makes vm_trace() fire call/return events for
instructions that have b_call/b_return events attached when the iseq is
running as a BMETHOD. The logic for rewriting to "trace_*" instruction
is tweaked so that when the user listens to call/return events,
instructions with b_call/b_return become trace variants.
To continue to provide the return value for non-local returns done using
the "return" or "break" keyword inside BMETHODs, the stack unwinding
code is tweaked. b_return events now provide the same return value as
return events for these non-local cases. A pre-existing test deemed not
providing a return value for these b_return events as a limitation.
This commit removes the checks for call/return TracePoint events that
happen when calling into BMETHODs when no TracePoints are active.
Technically, migrating just the return event is enough to fix the bug,
but migrating both call and return removes our reliance on
`VM_FRAME_FLAG_FINISH` and re-entering the interpreter when the caller
is already in the interpreter.
Implements setclassvariable in yjit. Note that this version is not
faster than the standard version because we aren't handling the inline
cache in assembly. This is still important to implement because it will
prevent yjit from exiting in methods that call both a cvar setter and
other code that yjit can compile.
Co-authored-by: Aaron Patterson tenderlove@ruby-lang.org
This provides a significant speedup for symbol, true, false,
nil, and 0-9, class/module, and a small speedup in most other cases.
Speedups (using included benchmarks):
:symbol :: 60%
0-9 :: 50%
Class/Module :: 50%
nil/true/false :: 20%
integer :: 10%
[] :: 10%
"" :: 3%
One reason this approach is faster is it reduces the number of
VM instructions for each interpolated value.
Initial idea, approach, and benchmarks from Eric Wong. I applied
the same approach against the master branch, updating it to handle
the significant internal changes since this was first proposed 4
years ago (such as CALL_INFO/CALL_CACHE -> CALL_DATA). I also
expanded it to optimize true/false/nil/0-9/class/module, and added
handling of missing methods, refined methods, and RUBY_DEBUG.
This renames the tostring insn to anytostring, and adds an
objtostring insn that implements the optimization. This requires
making a few functions non-static, and adding some non-static
functions.
This disables 4 YJIT tests. Those tests should be reenabled after
YJIT optimizes the new objtostring insn.
Implements [Feature #13715]
Co-authored-by: Eric Wong <e@80x24.org>
Co-authored-by: Alan Wu <XrXr@users.noreply.github.com>
Co-authored-by: Yusuke Endoh <mame@ruby-lang.org>
Co-authored-by: Koichi Sasada <ko1@atdot.net>
We only need the cref when we have a cache miss so don't look it up until we
need it. This likely speeds up class variable writes in the interpreter but
also simplifies the jit code.
Before
```
Warming up --------------------------------------
write a cvar 192.280k i/100ms
Calculating -------------------------------------
write a cvar 1.915M (± 3.5%) i/s - 9.614M in 5.026694s
```
After
```
Warming up --------------------------------------
write a cvar 216.308k i/100ms
Calculating -------------------------------------
write a cvar 2.140M (± 3.1%) i/s - 10.815M in 5.058079s
```
Followup to ruby/ruby#5137
* Refactor getclassvariable
We only need the cref when we have a cache miss so don't look it up until we
need it. This speeds up class variable reads in the interpreter but
also simplifies the jit code.
Benchmarks for master vs this branch (without yjit):
Before:
```
Warming up --------------------------------------
read a cvar 1.276M i/100ms
Calculating -------------------------------------
read a cvar 12.596M (± 1.7%) i/s - 63.781M in 5.064902s
```
After:
```
Warming up --------------------------------------
read a cvar 1.336M i/100ms
Calculating -------------------------------------
read a cvar 13.114M (± 3.6%) i/s - 65.488M in 5.000584s
```
Co-authored-by: Aaron Patterson <tenderlove@ruby-lang.org>
* Clean up function signatures / remove dead code
rb_vm_getclassvariable signature has changed and we don't need
rb_vm_get_cref.
Co-authored-by: Aaron Patterson <tenderlove@ruby-lang.org>
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.
In an effort to simplify the logic YJIT generates for accessing instance
variable, YJIT ensures that a given name-to-index mapping exists at
compile time. In the case that the mapping doesn't exist, it was created
by using rb_ivar_set() with Qundef on the sample object we see at
compile time. This hack isn't fine if the sample object happens to be
frozen, in which case YJIT would raise a FrozenError unexpectedly.
To deal with this, make a new function that only reserves the mapping
but doesn't touch the object. This is rb_obj_ensure_iv_index_mapping().
This new function superceeds the functionality of rb_iv_index_tbl_lookup()
so it was removed.
Reported by and includes a test case from John Hawthorn <john@hawthorn.email>
Fixes: GH-282
When YJIT make calls to routines without reconstructing interpreter
state through jit_prepare_routine_call(), it relies on the routine to
never allocate, raise, and push/pop control frames. Comment about this
on the routines that YJTI calls.
This is probably something we should dynamically verify on debug builds.
It's hard to statically verify this as it requires verifying all
functions in the call tree. Maybe something to look at in the future.
For upstreaming, we want functions we export either prefixed with "rb_"
or made static. Historically we haven't been following this rule, so we
were "leaking" a lot of symbols as `make leak-globals` would tell us.
This change unifies everything YJIT into a single compilation unit,
yjit.o, and makes everything unprefixed static to pass `make leak-globals`.
This manual "unified build" setup is similar to that of vm.o.
Having everything in one compilation unit allows static functions to
be visible across YJIT files and removes the need for declarations in
headers in some cases. Unnecessary declarations were removed.
Other changes of note:
- switched to MJIT_SYMBOL_EXPORT_BEGIN which indicates stuff as being
off limits for native extensions
- the first include of each YJIT file is change to be "internal.h"
- undefined MAP_STACK before explicitly redefining it since it
collide's with a definition in system headers. Consider renaming?
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.
* Implement calls to methods with simple optional params
* Remove unnecessary MJIT_STATIC
See comment for MJIT_STATIC. I added it not knowing whether it's
required because the function next to it has it. Don't use it and wait
for problems to come up instead.
* Better naming, some comments
* Count bailing on kw only iseqs
On railsbench:
```
opt_send_without_block exit reasons:
bmethod 59729 (27.7%)
optimized_method 59137 (27.5%)
iseq_complex_callee 41362 (19.2%)
alias_method 33346 (15.5%)
callsite_not_simple 19170 ( 8.9%)
iseq_only_keywords 1300 ( 0.6%)
kw_splat 1299 ( 0.6%)
cfunc_ruby_array_varg 18 ( 0.0%)
```
Make sure `opt_getinlinecache` is in a block all on its own, and
invalidate it from the interpreter when `opt_setinlinecache`.
It will recompile with a filled cache the second time around.
This lets YJIT runs well when the IC for constant is cold.
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
Koichi Sasada
Alan Wu
Kevin Newton
Nobuyoshi Nakada
Peter Zhu
Aaron Patterson
Jemma Issroff
John Hawthorn
Eileen M. Uchitelle
Jeremy Evans
Jean Boussier
Yusuke Endoh
Satoshi Moris Tagomori
eileencodes
Maxime Chevalier-Boisvert
Maxime Chevalier-Boisvert