iv_index_tbl manages instance variable indexes (ID -> index).
This data structure should be synchronized with other ractors
so introduce some VM locks.
This patch also introduced atomic ivar cache used by
set/getinlinecache instructions. To make updating ivar cache (IVC),
we changed iv_index_tbl data structure to manage (ID -> entry)
and an entry points serial and index. IVC points to this entry so
that cache update becomes atomically.
Before this commit, iclasses were "shady", or not protected by write
barriers. Because of that, the GC needs to spend more time marking these
objects than otherwise.
Applications that make heavy use of modules should see reduction in GC
time as they have a significant number of live iclasses on the heap.
- Put logic for iclass method table ownership into a function
- Remove calls to WB_UNPROTECT and insert write barriers for iclasses
This commit relies on the following invariant: for any non oirigin
iclass `I`, `RCLASS_M_TBL(I) == RCLASS_M_TBL(RBasic(I)->klass)`. This
invariant did not hold prior to 98286e9 for classes and modules that
have prepended modules.
[Feature #16984]
98286e9850 made it so that
`Module#include` allocates an origin iclass on each use. Since `include`
is widely used, the extra allocation can contribute significantly to
memory usage.
Instead of always allocating in anticipation of prepend, this change
takes a different approach. The new setup inserts a origin iclass into
the super chains of all the children of the module when prepend happens
for the first time.
rb_ensure_origin is made static again since now that adding an origin
now means walking over all usages, we want to limit the number of places
where we do it.
This fixes various issues when a module is included in or prepended
to a module or class, and then refined, or refined and then included
or prepended to a module or class.
Implement by renaming ensure_origin to rb_ensure_origin, making it
non-static, and calling it when refining a module.
Fix Module#initialize_copy to handle origins correctly. Previously,
Module#initialize_copy did not handle origins correctly. For example,
this code:
```ruby
module B; end
class A
def b; 2 end
prepend B
end
a = A.dup.new
class A
def b; 1 end
end
p a.b
```
Printed 1 instead of 2. This is because the super chain for
a.singleton_class was:
```
a.singleton_class
A.dup
B(iclass)
B(iclass origin)
A(origin) # not A.dup(origin)
```
The B iclasses would not be modified, so the includer entry would be
still be set to A and not A.dup.
This modifies things so that if the class/module has an origin,
all iclasses between the class/module and the origin are duplicated
and have the correct includer entry set, and the correct origin
is created.
This requires other changes to make sure all tests still pass:
* rb_undef_methods_from doesn't automatically handle classes with
origins, so pass it the origin for Comparable when undefing
methods in Complex. This fixed a failure in the Complex tests.
* When adding a method, the method cache was not cleared
correctly if klass has an origin. Clear the method cache for
the klass before switching to the origin of klass. This fixed
failures in the autoload tests related to overridding require,
without breaking the optimization tests. Also clear the method
cache for both the module and origin when removing a method.
* Module#include? is fixed to skip origin iclasses.
* Refinements are fixed to use the origin class of the module that
has an origin.
* RCLASS_REFINED_BY_ANY is removed as it was only used in a single
place and is no longer needed.
* Marshal#dump is fixed to skip iclass origins.
* rb_method_entry_make is fixed to handled overridden optimized
methods for modules that have origins.
Fixes [Bug #16852]
If a module has an origin, and that module is included in another
module or class, previously the iclass created for the module had
an origin pointer to the module's origin instead of the iclass's
origin.
Setting the origin pointer correctly requires using a stack, since
the origin iclass is not created until after the iclass itself.
Use a hidden ruby array to implement that stack.
Correctly assigning the origin pointers in the iclass caused a
use-after-free in GC. If a module with an origin is included
in a class, the iclass shares a method table with the module
and the iclass origin shares a method table with module origin.
Mark iclass origin with a flag that notes that even though the
iclass is an origin, it shares a method table, so the method table
should not be garbage collected. The shared method table will be
garbage collected when the module origin is garbage collected.
I've tested that this does not introduce a memory leak.
This change caused a VM assertion failure, which was traced to callable
method entries using the incorrect defined_class. Update
rb_vm_check_redefinition_opt_method and find_defined_class_by_owner
to treat iclass origins different than class origins to avoid this
issue.
This also includes a fix for Module#included_modules to skip
iclasses with origins.
Fixes [Bug #16736]
If a module has an origin, and that module is included in another
module or class, previously the iclass created for the module had
an origin pointer to the module's origin instead of the iclass's
origin.
Setting the origin pointer correctly requires using a stack, since
the origin iclass is not created until after the iclass itself.
Use a hidden ruby array to implement that stack.
Correctly assigning the origin pointers in the iclass caused a
use-after-free in GC. If a module with an origin is included
in a class, the iclass shares a method table with the module
and the iclass origin shares a method table with module origin.
Mark iclass origin with a flag that notes that even though the
iclass is an origin, it shares a method table, so the method table
should not be garbage collected. The shared method table will be
garbage collected when the module origin is garbage collected.
I've tested that this does not introduce a memory leak.
This also includes a fix for Module#included_modules to skip
iclasses with origins.
Fixes [Bug #16736]
According to MSVC manual (*1), cl.exe can skip including a header file
when that:
- contains #pragma once, or
- starts with #ifndef, or
- starts with #if ! defined.
GCC has a similar trick (*2), but it acts more stricter (e. g. there
must be _no tokens_ outside of #ifndef...#endif).
Sun C lacked #pragma once for a looong time. Oracle Developer Studio
12.5 finally implemented it, but we cannot assume such recent version.
This changeset modifies header files so that each of them include
strictly one #ifndef...#endif. I believe this is the most portable way
to trigger compiler optimizations. [Bug #16770]
*1: https://docs.microsoft.com/en-us/cpp/preprocessor/once
*2: https://gcc.gnu.org/onlinedocs/cppinternals/Guard-Macros.html
This patch contains several ideas:
(1) Disposable inline method cache (IMC) for race-free inline method cache
* Making call-cache (CC) as a RVALUE (GC target object) and allocate new
CC on cache miss.
* This technique allows race-free access from parallel processing
elements like RCU.
(2) Introduce per-Class method cache (pCMC)
* Instead of fixed-size global method cache (GMC), pCMC allows flexible
cache size.
* Caching CCs reduces CC allocation and allow sharing CC's fast-path
between same call-info (CI) call-sites.
(3) Invalidate an inline method cache by invalidating corresponding method
entries (MEs)
* Instead of using class serials, we set "invalidated" flag for method
entry itself to represent cache invalidation.
* Compare with using class serials, the impact of method modification
(add/overwrite/delete) is small.
* Updating class serials invalidate all method caches of the class and
sub-classes.
* Proposed approach only invalidate the method cache of only one ME.
See [Feature #16614] for more details.
Saves comitters' daily life by avoid #include-ing everything from
internal.h to make each file do so instead. This would significantly
speed up incremental builds.
We take the following inclusion order in this changeset:
1. "ruby/config.h", where _GNU_SOURCE is defined (must be the very
first thing among everything).
2. RUBY_EXTCONF_H if any.
3. Standard C headers, sorted alphabetically.
4. Other system headers, maybe guarded by #ifdef
5. Everything else, sorted alphabetically.
Exceptions are those win32-related headers, which tend not be self-
containing (headers have inclusion order dependencies).
This file has almost nothing to do. Added some #ifdef lines and
rearranged file contents.
Those macros are unable to translate into inline functions, because they
are used as lvalues of assignments.
One day, I could not resist the way it was written. I finally started
to make the code clean. This changeset is the beginning of a series of
housekeeping commits. It is a simple refactoring; split internal.h into
files, so that we can divide and concur in the upcoming commits. No
lines of codes are either added or removed, except the obvious file
headers/footers. The generated binary is identical to the one before.
