[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>
In preparation for https://bugs.ruby-lang.org/issues/20205.
The `frozen_string_literal` compilation option will no longer
be a boolean but a tri-state: `on/off/default`.
The following parts will not be shown for `-h` option. And not to
reach 80 columns. Some terminal emulators (Windows command prompt at
least) wrap the cursor to the next line when reaching the rightmost
column, before exceeding.
This `st_table` is used to both mark and pin classes
defined from the C API. But `vm->mark_object_ary` already
does both much more efficiently.
Currently a Ruby process starts with 252 rooted classes,
which uses `7224B` in an `st_table` or `2016B` in an `RArray`.
So a baseline of 5kB saved, but since `mark_object_ary` is
preallocated with `1024` slots but only use `405` of them,
it's a net `7kB` save.
`vm->mark_object_ary` is also being refactored.
Prior to this changes, `mark_object_ary` was a regular `RArray`, but
since this allows for references to be moved, it was marked a second
time from `rb_vm_mark()` to pin these objects.
This has the detrimental effect of marking these references on every
minors even though it's a mostly append only list.
But using a custom TypedData we can save from having to mark
all the references on minor GC runs.
Addtionally, immediate values are now ignored and not appended
to `vm->mark_object_ary` as it's just wasted space.
Before this commit, we were mixing a lot of concerns with the prism
compile between RubyVM::InstructionSequence and the general entry
points to the prism parser/compiler.
This commit makes all of the various prism-related APIs mirror
their corresponding APIs in the existing parser/compiler. This means
we now have the correct frame naming, and it's much easier to follow
where the logic actually flows. Furthermore this consolidates a lot
of the prism initialization, making it easier to see where we could
potentially be raising errors.
[Bug #20071]
Currently Ruby crashes when the --parser=prism flag is used either with
no input, or with input that is being redirected from stdin. So all of
the following will crash
ruby --parser=prism
ruby --parser=prism < test_code.rb
cat test_code.rb | ruby --parser=prism
This commit checks whether the input is assumed to be from stdin, and
then processes that as a file.
This will fix the second and third case above, but will cause a slight
behavioural changes for the first case - Ruby will treat stdin as an
empty file in this case and exit, rather than waiting for data to be
piped into stdin.
when the RUBY_FREE_ON_SHUTDOWN environment variable is set, manually free memory at shutdown.
Co-authored-by: Nobuyoshi Nakada <nobu@ruby-lang.org>
Co-authored-by: Peter Zhu <peter@peterzhu.ca>
Étienne Barrié
Kevin Newton
Jean Boussier
Nobuyoshi Nakada
Takashi Kokubun
Burdette Lamar
Yusuke Endoh
Matt Valentine-House
HParker
Aaron Patterson
Adam Hess
Jemma Issroff