summaryrefslogtreecommitdiff
path: root/bootstraptest
AgeCommit message (Collapse)Author
2022-05-20Special-case jit_guard_known_class for strings. This can remove (#5920)Noah Gibbs
runtime guard-checks for String#to_s, making some blocks too short to invalidate later. Add NOPs in those cases to reserve space. Notes: Merged-By: maximecb <maximecb@ruby-lang.org>
2022-04-27Rust YJITAlan Wu
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: https://github.com/Shopify/ruby/commit/1fd9573d8b4b65219f1c2407f30a0a60e537f8be 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> Notes: Merged: https://github.com/ruby/ruby/pull/5826
2022-04-06Raise RuntimeError if Kernel#binding is called from a non-Ruby frameJeremy Evans
Check whether the current or previous frame is a Ruby frame in call_trace_func and rb_tracearg_binding before attempting to create a binding for the frame. Fixes [Bug #18487] Co-authored-by: Alan Wu <XrXr@users.noreply.github.com> Notes: Merged: https://github.com/ruby/ruby/pull/5767 Merged-By: jeremyevans <code@jeremyevans.net>
2022-04-01Finer-grained constant cache invalidation (take 2)Kevin Newton
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] Notes: Merged: https://github.com/ruby/ruby/pull/5716
2022-04-01Revert "Raise RuntimeError if Kernel#binding is called from a non-Ruby frame"Jeremy Evans
This reverts commit 343ea9967e4a6b279eed6bd8e81ad0bdc747f254. This causes an assertion failure with -DRUBY_DEBUG=1 -DRGENGC_CHECK_MODE=2
2022-03-25Revert "Finer-grained inline constant cache invalidation"Nobuyoshi Nakada
This reverts commits for [Feature #18589]: * 8008fb7352abc6fba433b99bf20763cf0d4adb38 "Update formatting per feedback" * 8f6eaca2e19828e92ecdb28b0fe693d606a03f96 "Delete ID from constant cache table if it becomes empty on ISEQ free" * 629908586b4bead1103267652f8b96b1083573a8 "Finer-grained inline constant cache invalidation" MSWin builds on AppVeyor have been crashing since the merger. Notes: Merged: https://github.com/ruby/ruby/pull/5715 Merged-By: nobu <nobu@ruby-lang.org>
2022-03-24Raise RuntimeError if Kernel#binding is called from a non-Ruby frameJeremy Evans
Check whether the current or previous frame is a Ruby frame in call_trace_func before attempting to create a binding for the frame. Fixes [Bug #18487] Co-authored-by: Alan Wu <XrXr@users.noreply.github.com> Notes: Merged: https://github.com/ruby/ruby/pull/5567
2022-03-24Finer-grained inline constant cache invalidationKevin Newton
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. Notes: Merged: https://github.com/ruby/ruby/pull/5433
2022-02-17Reuse `-v` option result as `target_platform`Nobuyoshi Nakada
Backticks method invokes `/bin/sh` when the command contains quotes, and `sh` clears some environment variables set in runruby.rb to search the built shared library.
2022-02-17btest-ruby OPTS=-v should disable quietKoichi Sasada
`make btest-ruby` is run with -q (quiet) option and -v should remove -q option.
2022-02-14extend timeout for mjitKoichi Sasada
1 seconeds is not enough on an specific (busy) machine w/ mjit. http://ci.rvm.jp/results/trunk-mjit@phosphorus-docker/3830178
2022-02-06support concurrent btest executionKoichi Sasada
* `-j` option for concurrent test with threads * `-jN` uses N threads * `-j` uses nproc/2 threads * Introduce `BT` struct to manage configurations * Introduce `Assertion` to manage all assertions * Remove all toplevel instance variables * Show elapsed seconds at last ``` $ time make btest ... real 0m37.319s user 0m26.221s sys 0m16.534s $ time make btest TESTOPTS=-j ... real 0m11.812s user 0m36.667s sys 0m21.872s ``` Notes: Merged: https://github.com/ruby/ruby/pull/5528
2022-01-26refactoring btest outputKoichi Sasada
don't duplicate the message, but prepare `out` var to choose stdout/err. Notes: Merged: https://github.com/ruby/ruby/pull/5484
2022-01-21respect `--quiet` option for btestKoichi Sasada
Do not print anymore except errors.
2022-01-19[wasm] bootstraptest, basictest: disable backquote literal testsYuta Saito
WASI doesn't support spawning a new process for now. Notes: Merged: https://github.com/ruby/ruby/pull/5407
2022-01-10YJIT: Support kwargs for cfuncJohn Hawthorn
This adds support for passing keyword arguments to cfuncs. This is done by calling a helper method to create the hash from the top N values on the stack (determined by the callinfo) and then moving that value onto the stack. Notes: Merged: https://github.com/ruby/ruby/pull/5397
2022-01-08YJIT: Add support for ruby array cfuncs (argc=-2)John Hawthorn
This adds support for cfuncs which take variable arguments using a Ruby array. This is specified with the method entry's argc == -2. Notes: Merged: https://github.com/ruby/ruby/pull/5396
2022-01-07YJIT: Discard local var type info on routine callAlan Wu
Routines that are called from YJIT's output code can call methods, and calling methods mean they can capture and change the environment of the calling frame. Discard type info whenever we perform routine calls. This is more conservative than strictly necessary as some routines need to perform GC allocation but can never call methods and so should never be able to change local variables. However, manually analyzing C functions for whether they have code paths that call methods is error prone and can go out of date as changes land in the codebase. Closes: shopify/yjit#300 Notes: Merged: https://github.com/ruby/ruby/pull/5416
2021-12-31YJIT: Fix SP index with optarg and unordered kwargJohn Hawthorn
Previously when we were calling a method with an optional argument and multiple keywords arguments which weren't in the order the receiver expected we would use the wrong SP index to rearrange them. Fixes Bug #18453 Notes: Merged: https://github.com/ruby/ruby/pull/5379
2021-12-24@@cv is not accessible from non-main ractorsKoichi Sasada
Class variables (@@cv) is not accessible from non-main ractors. But without this patch cached @@cv can be read. fix [Bug #18128] Notes: Merged: https://github.com/ruby/ruby/pull/5335
2021-12-17YJIT: Fix check for required kwargsJohn Hawthorn
Previously, YJIT would not check that all the required keywords were specified in the case that there were optional arguments specified. In this case YJIT would incorrectly call the method with invalid arguments. Notes: Merged: https://github.com/ruby/ruby/pull/5285
2021-12-17YJIT: Allow iseq with both opt and kwargsJohn Hawthorn
Previously we mirrored the fast paths the interpreter had for having only one of kwargs or optional args. This commit aims to combine the cases and reduce complexity. Though this allows calling iseqs which have have both optional and keyword arguments, it requires that all optional arguments are specified when there are keyword arguments, since unspecified optional arguments appear before the kwargs. Support for this can be added a in a future PR. Notes: Merged: https://github.com/ruby/ruby/pull/5285
2021-12-16btest: assign $stderr = STDOUT instead of IO#reopen to be more portableYuta Saito
`IO#reopen` internally uses dup syscall but some platforms don't support the syscall. re-assigning `$stderr` is enough to capture the interpreter's errors and warnings. Notes: Merged: https://github.com/ruby/ruby/pull/5255
2021-12-14YJIT: Fix unexpected truncation when outputing VALUEAlan Wu
Previously, YJIT incorrectly discarded the upper 32 bits of the object pointer when writing out VALUEs to setup default keyword arguments. In addition to incorrectly truncating, the output pointers were not properly tracked for handling GC compaction moving the referenced objects. YJIT previously attempted to encode a mov instruction with a memory destination and a 64 bit immediate when there is no such encoding possible in the ISA. Add an assert to mitigate not being able to catch this at build time. Notes: Merged: https://github.com/ruby/ruby/pull/5274 Merged-By: XrXr
2021-12-15prohibit load by `autoload` on non-main RactorKoichi Sasada
fix [Bug #18120] Notes: Merged: https://github.com/ruby/ruby/pull/5267
2021-12-13Prepare for removing RubyVM::JIT (#5262)Takashi Kokubun
Notes: Merged-By: k0kubun <takashikkbn@gmail.com>
2021-12-09`Ractor.make_shareable` checks proc's seflKoichi Sasada
`Ractor.make_shareable(proc_obj)` raises an `IsolationError` if the self of `proc_obj` is not a shareable object. [Bug #18243] Notes: Merged: https://github.com/ruby/ruby/pull/5232
2021-12-08YJIT: Fix leak in compilation loopAlan Wu
Previously, when there are too many blocks in a batch, the last block in the batch is not tracked in the array of batches and not freed. Notes: Merged: https://github.com/ruby/ruby/pull/5229
2021-12-07YJIT: Remove guard_self_is_heap()Alan Wu
It's superseded by functionality added to jit_guard_known_klass(). In weird situations such as the ones in the included test, guard_self_is_heap() triggered assertions. Co-authored-by: Jemma Issroff <jemmaissroff@gmail.com> Notes: Merged: https://github.com/ruby/ruby/pull/5225
2021-12-06YJIT: Fix incomplete invalidation from opt_setinlinecacheAlan Wu
As part of YJIT's strategy for promoting Ruby constant expressions into constants in the output native code, the interpreter calls rb_yjit_constant_ic_update() from opt_setinlinecache. The block invalidation loop indirectly calls rb_darray_remove_unordered(), which does a shuffle remove. Because of this, looping with an incrementing counter like done previously can miss some elements in the array. Repeatedly invalidate the first element instead. The bug this commit resolves does not seem to cause crashes or divergent behaviors. Co-authored-by: Jemma Issroff <jemmaissroff@gmail.com> Notes: Merged: https://github.com/ruby/ruby/pull/5221
2021-12-04YJIT: Enable out of memory testsAlan Wu
As of [1] and [2], YJIT has enough support for out of memory conditions to pass these two basic tests. OOM code paths are prone to bugs since they are rarely exercised in common workloads. We might want to add CI runs that stress test these code paths. Maybe outside of GitHub Actions for capacity reasons. [1]: f41b4d44f95978dfa97af04af00055dc3fbf7978 [2]: b5b6ab4194f16e96ee5004288cc469ac1bca41a3 Notes: Merged: https://github.com/ruby/ruby/pull/5214
2021-12-02Lazily create singletons on instance_{exec,eval} (#5146)John Hawthorn
* 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> Notes: Merged-By: jhawthorn <john@hawthorn.email>
2021-12-01YJIT: Fail gracefully while OOM for new entry pointsAlan Wu
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. Notes: Merged: https://github.com/ruby/ruby/pull/5191
2021-11-26YJIT: Add ability to exit to interpreter from stubsAlan Wu
Previously, YJIT assumed that it's always possible to generate a new basic block when servicing a stub in branch_stub_hit(). When YJIT is out of executable memory, for example, this assumption doesn't hold up. Add handling to branch_stub_hit() for servicing stubs without consuming more executable memory by adding a code path that exits to the interpreter at the location the branch stub represents. The new code path reconstructs interpreter state in branch_stub_hit() and then exits with a new snippet called `code_for_exit_from_stub` that returns `Qundef` from the YJIT native stack frame. As this change adds another place where we regenerate code from `branch_t`, extract the logic for it into a new function and call it regenerate_branch(). While we are at it, make the branch shrinking code path in branch_stub_hit() more explicit. This new functionality is hard to test without full support for out of memory conditions. To verify this change, I ran `RUBY_YJIT_ENABLE=1 make check -j12` with the following patch to stress test the new code path: ```diff diff --git a/yjit_core.c b/yjit_core.c index 4ab63d9806..5788b8c5ed 100644 --- a/yjit_core.c +++ b/yjit_core.c @@ -878,8 +878,12 @@ branch_stub_hit(branch_t *branch, const uint32_t target_idx, rb_execution_contex cb_set_write_ptr(cb, branch->end_addr); } +if (rand() < RAND_MAX/2) { // Compile the new block version p_block = gen_block_version(target, target_ctx, ec); +}else{ + p_block = NULL; +} if (!p_block && branch_modified) { // We couldn't generate a new block for the branch, but we modified the branch. ``` We can enable the new test along with other OOM tests once full support lands. Other small changes: * yjit_utils.c (print_str): Update to work with new native frame shape. Follow up for 8fa0ee4d404. * yjit_iface.c (rb_yjit_init): Run yjit_init_core() after yjit_init_codegen() so `cb` and `ocb` are available. Notes: Merged: https://github.com/ruby/ruby/pull/5180 Merged-By: XrXr
2021-11-25YJIT: Implement new struct accessors (#5161)John Hawthorn
* YJIT: Implement optimized_method_struct_aref * YJIT: Implement struct_aref without method call Struct member reads can be compiled directly into a memory read (with either one or two levels of indirection). * YJIT: Implement optimized struct aset * YJIT: Update tests for struct access * YJIT: Add counters for remaining optimized methods * Check for INT32_MAX overflow It only takes a struct with 0x7fffffff/8+1 members. Also add some cheap compile time checks. * Add tests for non-embedded struct aref/aset Co-authored-by: Alan Wu <XrXr@users.noreply.github.com> Notes: Merged-By: jhawthorn <john@hawthorn.email>
2021-11-22YJIT: Make block invalidation more robustAlan Wu
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. Fixes Shopify/yjit#226 Notes: Merged: https://github.com/ruby/ruby/pull/5145
2021-11-19Add YJIT codegen for objtostring (#5149)Adam Hess
This is the minimal correct objtostring implementation in YJIT. For correctness, it is important that to_string not get called on strings or subclasses of string. There is a new test for this behavior. A follow up should implement an optimized version for other types as performed in `vm_objtostring`. Co-authored-by: John Hawthorn <jhawthorn@github.com> Co-authored-by: John Hawthorn <jhawthorn@github.com> Notes: Merged-By: maximecb <maximecb@ruby-lang.org>
2021-11-09Add one more test example for swap instructionNikita Vasilevsky
Notes: Merged: https://github.com/ruby/ruby/pull/5057
2021-11-07rb_id_serial_to_id: return unregistered ID as an internal IDNobuyoshi Nakada
```ruby def foo(*); ->{ super }; end ``` This code makes anonymous parameters which is not registered as an ID. The problem is that when Ractors try to scan `getlocal` instructions, it puts the Symbol corresponding to the parameter in to a hash. Since it is not registered, we end up with a strange exception. This commit wraps the unregistered ID in an internal ID so that we get the same exception for `...` as `*`. Co-Authored-By: Aaron Patterson <tenderlove@ruby-lang.org> Co-Authored-By: John Hawthorn <john@hawthorn.email> Notes: Merged: https://github.com/ruby/ruby/pull/5035
2021-11-05YJIT: Support iseq sends with mixed kwargs (#5082)John Hawthorn
* YJIT: Support iseq sends with mixed kwargs Co-authored-by: Kevin Newton <kddnewton@gmail.com> * Add additional comments to iseq sends Co-authored-by: Kevin Newton <kddnewton@gmail.com> Notes: Merged-By: maximecb <maximecb@ruby-lang.org>
2021-11-01YJIT: Support kwargs sends with all defaults (#5067)John Hawthorn
* YJIT: Support kwargs sends with all defaults Previously keyword argument methods were only compiled by YJIT when all keywords were specified in the caller. This adds support for calling methods with keyword arguments when no keyword arguments are specified and all are filled with the defaults. * Remove unused send_iseq_kwargs_none_passed Notes: Merged-By: maximecb <maximecb@ruby-lang.org>
2021-10-27YJIT: Support newhash with values (#5029)John Hawthorn
* YJIT: Implement newhash with values * YJIT: Add test of duphash * Fix compilation on macos/clang Notes: Merged-By: maximecb <maximecb@ruby-lang.org>
2021-10-27the core problem is the Proc is not shareableSatoshi Moris Tagomori
Notes: Merged: https://github.com/ruby/ruby/pull/4771
2021-10-25YJIT: Implement duphash (#5009)Ian C. Anderson
`duphash` showed up in the top-20 most frequent exit ops for @jhawthorn's benchmark that renders github.com/about The implementation was almost exactly the same as `duparray` Co-authored-by: John Hawthorn <john@hawthorn.email> Co-authored-by: John Hawthorn <john@hawthorn.email> Notes: Merged-By: maximecb <maximecb@ruby-lang.org>
2021-10-23allow to access ivars of classes/modulesKoichi Sasada
if an ivar of a class/module refer to a shareable object, this ivar can be read from non-main Ractors. Notes: Merged: https://github.com/ruby/ruby/pull/5006
2021-10-22Fix simple test on platforms where compaction is not supportedAlan Wu
844588f9157b364244a7d34ee0fcc70ccc2a7dd9 made it so that trying to call gc_verify_compaction_references on unsupported platform result in an exception rather than a crash. Rescue the exception in a YJIT btest that uses gc_verify_compaction_references. Notes: Merged: https://github.com/ruby/ruby/pull/5004 Merged-By: XrXr
2021-10-21YJIT: don't compile attr_accessor methods when tracing (#4998)Alan Wu
2d98593bf54a37397c6e4886ccc7e3654c2eaf85 made it so that attr_accessor methods fire C method tracing events. Previously, we weren't checking for whether we are tracing before compiling, leading to missed events. Since global invalidation invalidates all code, and that attr_accessor methods can never enable tracing while running, events are only dropped when YJIT tries to compile when tracing is already enabled. Factor out the code for checking tracing and check it before generating code for attr_accessor methods. This change fixes TestSetTraceFunc#test_tracepoint_attr when it's ran in isolation. Notes: Merged-By: maximecb
2021-10-21* append newline at EOF. [ci skip]git
2021-10-20Do kwarg shuffle after checking for interruptsAlan Wu
Previously, we were shuffling keyword arguments before checking for interrupts. In the case that we side exit in the interrupt check, we left the interpreter with an already-shuffled argument list for the call, resulting in a double shuffle, leaving the locals in the wrong order for the callee. Do keyword shuffling after all the possible side exits. Co-authored-by: Kevin Newton <kddnewton@gmail.com>
2021-10-20Extract yjit_force_iv_index and make it work when object is frozenAlan Wu
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