[Feature #20205]
As a path toward enabling frozen string literals by default in the future,
this commit introduce "chilled strings". From a user perspective chilled
strings pretend to be frozen, but on the first attempt to mutate them,
they lose their frozen status and emit a warning rather than to raise a
`FrozenError`.
Implementation wise, `rb_compile_option_struct.frozen_string_literal` is
no longer a boolean but a tri-state of `enabled/disabled/unset`.
When code is compiled with frozen string literals neither explictly enabled
or disabled, string literals are compiled with a new `putchilledstring`
instruction. This instruction is identical to `putstring` except it marks
the String with the `STR_CHILLED (FL_USER3)` and `FL_FREEZE` flags.
Chilled strings have the `FL_FREEZE` flag as to minimize the need to check
for chilled strings across the codebase, and to improve compatibility with
C extensions.
Notes:
- `String#freeze`: clears the chilled flag.
- `String#-@`: acts as if the string was mutable.
- `String#+@`: acts as if the string was mutable.
- `String#clone`: copies the chilled flag.
Co-authored-by: Jean Boussier <byroot@ruby-lang.org>
This frees FL_USER0 on both T_MODULE and T_CLASS.
Note: prior to this, FL_SINGLETON was never set on T_MODULE,
so checking for `FL_SINGLETON` without first checking that
`FL_TYPE` was `T_CLASS` was valid. That's no longer the case.
comptime_key is a Ruby object and the value is not valid in machine code.
This PR also implements `CMP r/m64, imm32 (Mod 01: [reg]+disp8)` that is
now needed for running mail.gem benchmark.
Right now the `rb_shape_get_next` shape caller need to
first check if there is capacity left, and if not call
`rb_shape_transition_shape_capa` before it can call `rb_shape_get_next`.
And on each of these it needs to checks if we got a TOO_COMPLEX
back.
All this logic is duplicated in the interpreter, YJIT and RJIT.
Instead we can have `rb_shape_get_next` do the capacity transition
when needed. The caller can compare the old and new shapes capacity
to know if resizing is needed. It also can check for TOO_COMPLEX
only once.
Remove rb_control_frame_t::__bp__ and optimize bmethod calls
This commit removes the __bp__ field from rb_control_frame_t. It was
introduced to help MJIT, but since MJIT was replaced by RJIT, we can use
vm_base_ptr() to compute it from the SP of the previous control frame
instead. Removing the field avoids needing to set it up when pushing new
frames.
Simply removing __bp__ would cause crashes since RJIT and YJIT used a
slightly different stack layout for bmethod calls than the interpreter.
At the moment of the call, the two layouts looked as follows:
┌────────────┐ ┌────────────┐
│ frame_base │ │ frame_base │
├────────────┤ ├────────────┤
│ ... │ │ ... │
├────────────┤ ├────────────┤
│ args │ │ args │
├────────────┤ └────────────┘<─prev_frame_sp
│ receiver │
prev_frame_sp─>└────────────┘
RJIT & YJIT interpreter
Essentially, vm_base_ptr() needs to compute the address to frame_base
given prev_frame_sp in the diagrams. The presence of the receiver
created an off-by-one situation.
Make the interpreter use the layout the JITs use for iseq-to-iseq
bmethod calls. Doing so removes unnecessary argument shifting and
vm_exec_core() re-entry from the interpreter, yielding a speed
improvement visible through `benchmark/vm_defined_method.yml`:
patched: 7578743.1 i/s
master: 4796596.3 i/s - 1.58x slower
C-to-iseq bmethod calls now store one more VALUE than before, but that
should have negligible impact on overall performance.
Note that re-entering vm_exec_core() used to be necessary for firing
TracePoint events, but that's no longer the case since
9121e57a5f.
Closesruby/ruby#6428
* YJIT: Fix autosplat miscomp for blocks with optionals
When passing an array as the sole argument to `yield`, and the yieldee
takes more than 1 optional parameter, the array is expanded similar
to `*array` splat calls. This is called "autosplat" in
`setup_parameters_complex()`.
Previously, YJIT did not detect this autosplat condition. It passed the
array without expanding it, deviating from interpreter behavior.
Detect this conditon and refuse to compile it.
Fixes: Shopify/yjit#313
* RJIT: Fix autosplat miscomp for blocks with optionals
This is mirrors the same issue as YJIT. See previous commit.
* Unify length field for embedded and heap strings
The length field is of the same type and position in RString for both
embedded and heap allocated strings, so we can unify it.
* Remove RSTRING_EMBED_LEN
Remove !USE_RVARGC code
[Feature #19579]
The Variable Width Allocation feature was turned on by default in Ruby
3.2. Since then, we haven't received bug reports or backports to the
non-Variable Width Allocation code paths, so we assume that nobody is
using it. We also don't plan on maintaining the non-Variable Width
Allocation code, so we are going to remove it.
