This reverts commit 6cb6d5abc3.
This reverts commit 1484b786ae.
I think we don't need these assertions anymore. I believe the problem
is solved by abf678a439
We are seeing an error where code that is generated with MJIT contains
references to objects that have been moved. I believe this is due to a
race condition in the compaction function.
`gc_compact` has two steps:
1. Run a full GC to pin objects
2. Compact / update references
Step one is executed with `garbage_collect`. `garbage_collect` calls
`gc_enter` / `gc_exit`, these functions acquire a JIT lock and release a
JIT lock. So a lock is held for the duration of step 1.
Step two is executed by `gc_compact_after_gc`. It also holds a JIT
lock.
I believe the problem is that the JIT is free to execute between step 1
and step 2. It copies call cache values, but doesn't pin them when it
copies them. So the compactor thinks it's OK to move the call cache
even though it is not safe.
We need to hold a lock for the duration of `garbage_collect` *and*
`gc_compact_after_gc`. This patch introduces a lock level which
increments and decrements. The compaction function can increment and
decrement the lock level and prevent MJIT from executing during both
steps.
Accessing a shareable object is prohibitted because it can cause
race condition, but if the shareable object is frozen, there is no
problem to access ivars.
rb_ractor_belonging() returns 0 only if it has sharable flag.
rb_ractor_confirm_belonging() checks rb_ractor_shareable_p()
if the belonging ractor id is different from current ractor id.
20201021T123003Z.log.html.gz
```
/home/chkbuild/chkbuild/tmp/build/20201021T123003Z/ruby/test/json/json_parser_test.rb:227: warning: ambiguous first argument; put parentheses or a space even after `-' operator
/home/chkbuild/chkbuild/tmp/build/20201021T123003Z/ruby/test/json/json_parser_test.rb:228: warning: ambiguous first argument; put parentheses or a space even after `-' operator
```
rb_objspace_reachable_objects_from(obj) is used to traverse all
reachable objects from obj. This function modify objspace but it
is not ractor-safe (thread-safe). This patch fix the problem.
Strategy:
(1) call GC mark process during_gc
(2) call Ractor-local custom mark func when !during_gc
Introduce new method Ractor.make_shareable(obj) which tries to make
obj shareable object. Protocol is here.
(1) If obj is shareable, it is shareable.
(2) If obj is not a shareable object and if obj can be shareable
object if it is frozen, then freeze obj. If obj has reachable
objects (rs), do rs.each{|o| Ractor.make_shareable(o)}
recursively (recursion is not Ruby-level, but C-level).
(3) Otherwise, raise Ractor::Error. Now T_DATA is not a shareable
object even if the object is frozen.
If the method finished without error, given obj is marked as
a sharable object.
To allow makng a shareable frozen T_DATA object, then set
`RUBY_TYPED_FROZEN_SHAREABLE` as type->flags. On default,
this flag is not set. It means user defined T_DATA objects are
not allowed to become shareable objects when it is frozen.
You can make any object shareable by setting FL_SHAREABLE flag,
so if you know that the T_DATA object is shareable (== thread-safe),
set this flag, at creation time for example. `Ractor` object is one
example, which is not a frozen, but a shareable object.
* Support ArithmeticSequence in Array#slice
* Extract rb_range_component_beg_len
* Use rb_range_values to check Range object
* Fix ary_make_partial_step
* Fix for negative step cases
* range.c: Describe the role of err argument in rb_range_component_beg_len
* Raise a RangeError when an arithmetic sequence refers the outside of an array
[Feature #16812]
