which has been developed by Takashi Kokubun <takashikkbn@gmail> as
YARV-MJIT. Many of its bugs are fixed by wanabe <s.wanabe@gmail.com>.
This JIT compiler is designed to be a safe migration path to introduce
JIT compiler to MRI. So this commit does not include any bytecode
changes or dynamic instruction modifications, which are done in original
MJIT.
This commit even strips off some aggressive optimizations from
YARV-MJIT, and thus it's slower than YARV-MJIT too. But it's still
fairly faster than Ruby 2.5 in some benchmarks (attached below).
Note that this JIT compiler passes `make test`, `make test-all`, `make
test-spec` without JIT, and even with JIT. Not only it's perfectly safe
with JIT disabled because it does not replace VM instructions unlike
MJIT, but also with JIT enabled it stably runs Ruby applications
including Rails applications.
I'm expecting this version as just "initial" JIT compiler. I have many
optimization ideas which are skipped for initial merging, and you may
easily replace this JIT compiler with a faster one by just replacing
mjit_compile.c. `mjit_compile` interface is designed for the purpose.
common.mk: update dependencies for mjit_compile.c.
internal.h: declare `rb_vm_insn_addr2insn` for MJIT.
vm.c: exclude some definitions if `-DMJIT_HEADER` is provided to
compiler. This avoids to include some functions which take a long time
to compile, e.g. vm_exec_core. Some of the purpose is achieved in
transform_mjit_header.rb (see `IGNORED_FUNCTIONS`) but others are
manually resolved for now. Load mjit_helper.h for MJIT header.
mjit_helper.h: New. This is a file used only by JIT-ed code. I'll
refactor `mjit_call_cfunc` later.
vm_eval.c: add some #ifdef switches to skip compiling some functions
like Init_vm_eval.
win32/mkexports.rb: export thread/ec functions, which are used by MJIT.
include/ruby/defines.h: add MJIT_FUNC_EXPORTED macro alis to clarify
that a function is exported only for MJIT.
array.c: export a function used by MJIT.
bignum.c: ditto.
class.c: ditto.
compile.c: ditto.
error.c: ditto.
gc.c: ditto.
hash.c: ditto.
iseq.c: ditto.
numeric.c: ditto.
object.c: ditto.
proc.c: ditto.
re.c: ditto.
st.c: ditto.
string.c: ditto.
thread.c: ditto.
variable.c: ditto.
vm_backtrace.c: ditto.
vm_insnhelper.c: ditto.
vm_method.c: ditto.
I would like to improve maintainability of function exports, but I
believe this way is acceptable as initial merging if we clarify the
new exports are for MJIT (so that we can use them as TODO list to fix)
and add unit tests to detect unresolved symbols.
I'll add unit tests of JIT compilations in succeeding commits.
Author: Takashi Kokubun <takashikkbn@gmail.com>
Contributor: wanabe <s.wanabe@gmail.com>
Part of [Feature #14235]
---
* Known issues
* Code generated by gcc is faster than clang. The benchmark may be worse
in macOS. Following benchmark result is provided by gcc w/ Linux.
* Performance is decreased when Google Chrome is running
* JIT can work on MinGW, but it doesn't improve performance at least
in short running benchmark.
* Currently it doesn't perform well with Rails. We'll try to fix this
before release.
---
* Benchmark reslts
Benchmarked with:
Intel 4.0GHz i7-4790K with 16GB memory under x86-64 Ubuntu 8 Cores
- 2.0.0-p0: Ruby 2.0.0-p0
- r62186: Ruby trunk (early 2.6.0), before MJIT changes
- JIT off: On this commit, but without `--jit` option
- JIT on: On this commit, and with `--jit` option
** Optcarrot fps
Benchmark: https://github.com/mame/optcarrot
| |2.0.0-p0 |r62186 |JIT off |JIT on |
|:--------|:--------|:--------|:--------|:--------|
|fps |37.32 |51.46 |51.31 |58.88 |
|vs 2.0.0 |1.00x |1.38x |1.37x |1.58x |
** MJIT benchmarks
Benchmark: https://github.com/benchmark-driver/mjit-benchmarks
(Original: https://github.com/vnmakarov/ruby/tree/rtl_mjit_branch/MJIT-benchmarks)
| |2.0.0-p0 |r62186 |JIT off |JIT on |
|:----------|:--------|:--------|:--------|:--------|
|aread |1.00 |1.09 |1.07 |2.19 |
|aref |1.00 |1.13 |1.11 |2.22 |
|aset |1.00 |1.50 |1.45 |2.64 |
|awrite |1.00 |1.17 |1.13 |2.20 |
|call |1.00 |1.29 |1.26 |2.02 |
|const2 |1.00 |1.10 |1.10 |2.19 |
|const |1.00 |1.11 |1.10 |2.19 |
|fannk |1.00 |1.04 |1.02 |1.00 |
|fib |1.00 |1.32 |1.31 |1.84 |
|ivread |1.00 |1.13 |1.12 |2.43 |
|ivwrite |1.00 |1.23 |1.21 |2.40 |
|mandelbrot |1.00 |1.13 |1.16 |1.28 |
|meteor |1.00 |2.97 |2.92 |3.17 |
|nbody |1.00 |1.17 |1.15 |1.49 |
|nest-ntimes|1.00 |1.22 |1.20 |1.39 |
|nest-while |1.00 |1.10 |1.10 |1.37 |
|norm |1.00 |1.18 |1.16 |1.24 |
|nsvb |1.00 |1.16 |1.16 |1.17 |
|red-black |1.00 |1.02 |0.99 |1.12 |
|sieve |1.00 |1.30 |1.28 |1.62 |
|trees |1.00 |1.14 |1.13 |1.19 |
|while |1.00 |1.12 |1.11 |2.41 |
** Discourse's script/bench.rb
Benchmark: https://github.com/discourse/discourse/blob/v1.8.7/script/bench.rb
NOTE: Rails performance was somehow a little degraded with JIT for now.
We should fix this.
(At least I know opt_aref is performing badly in JIT and I have an idea
to fix it. Please wait for the fix.)
*** JIT off
Your Results: (note for timings- percentile is first, duration is second in millisecs)
categories_admin:
50: 17
75: 18
90: 22
99: 29
home_admin:
50: 21
75: 21
90: 27
99: 40
topic_admin:
50: 17
75: 18
90: 22
99: 32
categories:
50: 35
75: 41
90: 43
99: 77
home:
50: 39
75: 46
90: 49
99: 95
topic:
50: 46
75: 52
90: 56
99: 101
*** JIT on
Your Results: (note for timings- percentile is first, duration is second in millisecs)
categories_admin:
50: 19
75: 21
90: 25
99: 33
home_admin:
50: 24
75: 26
90: 30
99: 35
topic_admin:
50: 19
75: 20
90: 25
99: 30
categories:
50: 40
75: 44
90: 48
99: 76
home:
50: 42
75: 48
90: 51
99: 89
topic:
50: 49
75: 55
90: 58
99: 99
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@62197 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* vm_backtrace.c (rb_ec_backtrace_location_ary): make it static and
remove `rb_` prefix.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@60809 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* tool/instruction.rb: create `trace_` prefix instructions.
* compile.c (ADD_TRACE): do not add `trace` instructions but add
TRACE link elements. TRACE elements will be unified with a next
instruction as instruction information.
* vm_trace.c (update_global_event_hook): modify all ISeqs when
hooks are enabled.
* iseq.c (rb_iseq_trace_set): added to toggle `trace_` instructions.
* vm_insnhelper.c (vm_trace): added.
This function is a body of `trace_` prefix instructions.
* vm_insnhelper.h (JUMP): save PC to a control frame.
* insns.def (trace): removed.
* vm_exec.h (INSN_ENTRY_SIG): add debug output (disabled).
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@60763 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* iseq.c (find_line_no): renamed to rb_iseq_line_no().
* vm_backtrace.c (calc_lineno): add a comment why we need to use "pos-1".
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@60733 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* vm_backtrace.c (rb_backtrace_use_iseq_first_lineno_for_last_location):
added. It modifies last location's line as corresponding iseq's first line
number.
* vm_args.c (raise_argument_error): use added function.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@60725 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
to represent execution context [Feature #14038]
* vm_core.h (rb_thread_t): rb_thread_t::ec is now a pointer.
There are many code using `th` to represent execution context
(such as cfp, VM stack and so on). To access `ec`, they need to
use `th->ec->...` (adding one indirection) so that we need to
replace them by passing `ec` instead of `th`.
* vm_core.h (GET_EC()): introduced to access current ec. Also
remove `ruby_current_thread` global variable.
* cont.c (rb_context_t): introduce rb_context_t::thread_ptr instead of
rb_context_t::thread_value.
* cont.c (ec_set_vm_stack): added to update vm_stack explicitly.
* cont.c (ec_switch): added to switch ec explicitly.
* cont.c (rb_fiber_close): added to terminate fibers explicitly.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@60440 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* vm_core.h (rb_thread_ptr): added to replace GetThreadPtr() macro.
* thread.c (in some functions: use "target_th" instead of "th" to make clear
that it is not a current thread.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@59192 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Return value of EXEC_TAG() is saved by "int state".
Instead of "int", use "enum ruby_tag_type". First EXEC_TAG()
value should be 0, so that define TAG_NONE (= 0) and use it.
Some code used "status" instead of "state". To make them clear,
rename them to state.
We can change variable name from "state" to "tag_state", but this
ticket doesn't contain it.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@59155 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* vm_core.h: rename absolute_path to realpath because it is expected name.
external APIs (#absolute_path methods) are remained.
* vm_core.h: remove rb_iseq_location_struct::path and
rb_iseq_location_struct::absolute_path and introduce pathobj.
if given path equals to given absolute_path (and most of case
it is true), pathobj is simply given path String. If it is not same,
pathobj is Array and pathobj[0] is path and pathobj[1] is realpath.
This size optimization reduce 8 bytes and
sizeof(struct rb_iseq_constant_body) is 200 bytes -> 192 bytes
on 64bit CPU.
To support this change, the following functions are introduced:
* pathobj_path() (defined in vm_core.h)
* pathobj_realpath() (ditto)
* rb_iseq_path() (decl. in vm_core.h)
* rb_iseq_realpath() (ditto)
* rb_iseq_pathobj_new() (ditto)
* rb_iseq_pathobj_set() (ditto)
* vm_core.h (rb_binding_t): use pathobj instead of path. If binding
is given at eval methods, realpath (absolute_path) was caller's
realpath. However, they should use binding's realpath.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58979 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
The goal is to reduce rb_context_t and rb_fiber_t size
by removing the need to store the entire rb_thread_t in
there.
[ruby-core:81045] Work-in-progress: soon, we will move more fields here.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58614 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* vm_backtrace.c (rb_threadptr_backtrace_object): rename and
extern.
* vm_backtrace.c (rb_threadptr_backtrace_str_ary): rename as
threadptr since the parameter is rb_thread_t*.
* vm_backtrace.c (rb_threadptr_backtrace_location_ary): ditto.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58377 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
actually check its availability rather to check GCC's version.
* configure.in (WARN_UNUSED_RESULT): moved to here.
* configure.in (RUBY_FUNC_ATTRIBUTE): change function declaration
to return int rather than void, because it makes no sense for a
warn_unused_result attributed function to return void.
Funny thing however is that it also makes no sense for noreturn
attributed function to return int. So there is a fundamental
conflict between them. While I tested this, I confirmed both
GCC 6 and Clang 3.8 prefers int over void to correctly detect
necessary attributes under this setup. Maybe subject to change
in future.
* internal.h (UNINITIALIZED_VAR): renamed to MAYBE_UNUSED, then
moved to configure.in for the same reason we move
WARN_UNUSED_RESULT.
* configure.in (MAYBE_UNUSED): moved to here.
* internal.h (__has_attribute): deleted, because it has no use now.
* string.c (rb_str_enumerate_lines): refactor macro rename.
* string.c (rb_str_enumerate_bytes): ditto.
* string.c (rb_str_enumerate_chars): ditto.
* string.c (rb_str_enumerate_codepoints): ditto.
* thread.c (do_select): ditto.
* vm_backtrace.c (rb_debug_inspector_open): ditto.
* vsnprintf.c (BSD_vfprintf): ditto.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@56169 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
and VM_FRAME_CFRAME_P().
Most of case, RUBY_VM_NORMAL_ISEQ_P() is no
longer needed.
* vm_core.h: introduce rb_obj_is_iseq().
* cont.c, vm.c: VM_FRAME_MAGIC_DUMMY with
VM_FRAME_FLAG_CFRAME.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@55804 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* vm_eval.c (rb_eval_cmd, rb_catch_obj): use TH_JUMP_TAG with the
same rb_thread_t used for TH_PUSH_TAG, instead of JUMP_TAG with
the current thread global variable.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@54914 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* ruby.c (load_file_internal, ruby_process_options): share
ruby_engine instead of literal strings.
* version.c (Init_version): remove internal `ruby_engine_name`,
but set the VM program name in addition to the global constant.
* vm_backtrace.c (location_to_str, oldbt_init): use th eVM program
name always.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@52782 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
All contents of previous rb_iseq_t is in rb_iseq_t::body.
Remove rb_iseq_t::self because rb_iseq_t is an object.
RubyVM::InstructionSequence is wrapper object points T_IMEMO/iseq.
So RubyVM::ISeq.of(something) method returns different wrapper
objects but they point the same T_IMEMO/iseq object.
This patch is big, but most of difference is replacement of
iseq->xxx to iseq->body->xxx.
(previous) rb_iseq_t::compile_data is also located to
rb_iseq_t::compile_data.
It was moved from rb_iseq_body::compile_data.
Now rb_iseq_t has empty two pointers.
I will split rb_iseq_body data into static data and dynamic data.
* compile.c: rename some functions/macros.
Now, we don't need to separate iseq and iseqval (only VALUE).
* eval.c (ruby_exec_internal): `n' is rb_iseq_t (T_IMEMO/iseq).
* ext/objspace/objspace.c (count_imemo_objects): count T_IMEMO/iseq.
* gc.c: check T_IMEMO/iseq.
* internal.h: add imemo_type::imemo_iseq.
* iseq.c: define RubyVM::InstructionSequnce as T_OBJECT.
Methods are implemented by functions named iseqw_....
* load.c (rb_load_internal0): rb_iseq_new_top() returns
rb_iseq_t (T_IMEMO/iesq).
* method.h (rb_add_method_iseq): accept rb_iseq_t (T_IMEMO/iseq).
* vm_core.h (GetISeqPtr): removed because it is not T_DATA now.
* vm_core.h (struct rb_iseq_body): remove padding for
[Bug #10037][ruby-core:63721].
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@51327 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* internal.h, iseq.c (rb_iseq_klass): remove it because
rb_iseq_t::klass is removed.
* vm_insnhelper.c (vm_super_outside): do not see cfp->iseq, but
check callable method entry on a frame.
This fix simplify the logic to search super class.
* test/ruby/test_method.rb: support super() from Proc.
Now, [Bug #4881] and [Bug #3136] was solved.
* proc.c (rb_mod_define_method): catch up this change.
* vm.c (vm_define_method): ditto.
* vm_backtrace.c (rb_profile_frames): now, each `frame' objects
are rb_callable_method_entry_t data or iseq VALUEs.
This fix introduce minor compatibility issue that
rb_profile_frame_label() always returns
rb_profile_frame_base_label().
* test/-ext-/debug/test_profile_frames.rb: catch up this change.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@51166 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
rb_control_frame_t::klass.
[Bug #11278], [Bug #11279]
rb_method_entry_t data belong to modules/classes.
rb_method_entry_t::owner points defined module or class.
module M
def foo; end
end
In this case, owner is M.
rb_callable_method_entry_t data belong to only classes.
For modules, MRI creates corresponding T_ICLASS internally.
rb_callable_method_entry_t can also belong to T_ICLASS.
rb_callable_method_entry_t::defined_class points T_CLASS or
T_ICLASS.
rb_method_entry_t data for classes (not for modules) are also
rb_callable_method_entry_t data because it is completely same data.
In this case, rb_method_entry_t::owner == rb_method_entry_t::defined_class.
For example, there are classes C and D, and incldues M,
class C; include M; end
class D; include M; end
then, two T_ICLASS objects for C's super class and D's super class
will be created.
When C.new.foo is called, then M#foo is searcheed and
rb_callable_method_t data is used by VM to invoke M#foo.
rb_method_entry_t data is only one for M#foo.
However, rb_callable_method_entry_t data are two (and can be more).
It is proportional to the number of including (and prepending)
classes (the number of T_ICLASS which point to the module).
Now, created rb_callable_method_entry_t are collected when
the original module M was modified. We can think it is a cache.
We need to select what kind of method entry data is needed.
To operate definition, then you need to use rb_method_entry_t.
You can access them by the following functions.
* rb_method_entry(VALUE klass, ID id);
* rb_method_entry_with_refinements(VALUE klass, ID id);
* rb_method_entry_without_refinements(VALUE klass, ID id);
* rb_resolve_refined_method(VALUE refinements, const rb_method_entry_t *me);
To invoke methods, then you need to use rb_callable_method_entry_t
which you can get by the following APIs corresponding to the
above listed functions.
* rb_callable_method_entry(VALUE klass, ID id);
* rb_callable_method_entry_with_refinements(VALUE klass, ID id);
* rb_callable_method_entry_without_refinements(VALUE klass, ID id);
* rb_resolve_refined_method_callable(VALUE refinements, const rb_callable_method_entry_t *me);
VM pushes rb_callable_method_entry_t, so that rb_vm_frame_method_entry()
returns rb_callable_method_entry_t.
You can check a super class of current method by
rb_callable_method_entry_t::defined_class.
* method.h: renamed from rb_method_entry_t::klass to
rb_method_entry_t::owner.
* internal.h: add rb_classext_struct::callable_m_tbl to cache
rb_callable_method_entry_t data.
We need to consider abotu this field again because it is only
active for T_ICLASS.
* class.c (method_entry_i): ditto.
* class.c (rb_define_attr): rb_method_entry() does not takes
defiend_class_ptr.
* gc.c (mark_method_entry): mark RCLASS_CALLABLE_M_TBL() for T_ICLASS.
* cont.c (fiber_init): rb_control_frame_t::klass is removed.
* proc.c: fix `struct METHOD' data structure because
rb_callable_method_t has all information.
* vm_core.h: remove several fields.
* rb_control_frame_t::klass.
* rb_block_t::klass.
And catch up changes.
* eval.c: catch up changes.
* gc.c: ditto.
* insns.def: ditto.
* vm.c: ditto.
* vm_args.c: ditto.
* vm_backtrace.c: ditto.
* vm_dump.c: ditto.
* vm_eval.c: ditto.
* vm_insnhelper.c: ditto.
* vm_method.c: ditto.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@51126 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Motivation and new data structure are described in [Bug #11203].
This patch also solve the following issues.
* [Bug #11200] Memory leak of method entries
* [Bug #11046] __callee__ returns incorrect method name in orphan
proc
* test/ruby/test_method.rb: add a test for [Bug #11046].
* vm_core.h: remvoe rb_control_frame_t::me. me is located at value
stack.
* vm_core.h, gc.c, vm_method.c: remove unlinked_method... codes
because method entries are simple VALUEs.
* method.h: Now, all method entries has own independent method
definititons. Strictly speaking, this change is not essential,
but for future changes.
* rb_method_entry_t::flag is move to rb_method_definition_t::flag.
* rb_method_definition_t::alias_count is now
rb_method_definition_t::alias_count_ptr, a pointer to the counter.
* vm_core.h, vm_insnhelper.c (rb_vm_frame_method_entry) added to
search the current method entry from value stack.
* vm_insnhelper.c (VM_CHECK_MODE): introduced to enable/disable
assertions.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@50728 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* vm_backtrace.c (location_base_label): convert ID to string
directly, and the return value is frozen.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@50307 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
use 0 for rb_data_type_t::reserved instead of NULL, since its type
may be changed in the future and possibly not a pointer type.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48662 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
remove rb_binding_new_with_cfp, and use rb_vm_make_binding instead.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48001 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* vm_backtrace.c (id2str): adapt rb_id2str which returns 0 on
unknown ID to return Qnil, since oldbt_arg functions expect Qnil
on unknown method names.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@47951 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* vm_backtrace.c (location_format): adjust unknown name method
results to other functions.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@47950 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* process.c (free_exec_arg): remove
(memsize_exec_arg): ptr is never NULL
(exec_arg_data_type): use RUBY_TYPED_DEFAULT_FREE
* variable.c (autoload_i_free): remove
(autoload_data_i_type): use RUBY_TYPED_DEFAULT_FREE
(autoload_memsize): ptr is never NULL
* vm_backtrace.c (location_free): remove
(location_mark): ptr is never NULL
(location_data_type): use RUBY_TYPED_DEFAULT_FREE
(backtrace_mark): ditto
(backtrace_free): ditto
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@47572 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Now, there are no setter and independent from Exception#backtrace.
[Feature #8960]
* eval.c (setup_exception): set backtrace locations for `bt_location'
special attribute.
* vm_backtrace.c (rb_backtrace_to_location_ary): added.
* internal.h: ditto.
* test/ruby/test_backtrace.rb: add a test for
Exception#backtrace_locations.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@44170 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
directly, since it might have a custom implementation or show ivars.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@43443 b2dd03c8-39d4-4d8f-98ff-823fe69b080e