This removes all support for GC mode.
This was deprecated by Apple in OS X 10.8 (2012) and never supported in
iOS. Very little code ever tried to use it with this runtime.
It's gone from the build system already.
- Don't call C++ constructors if they don't exist.
- Don't check the owner of retain / release methods if they are not implemented.
- Add arc.m as a file to ignore when checking for GC compatibility.
does run-time detection of whether to use GC calls objc_collecting_enabled()
(sometimes indirectly, via NSGarbageCollector) to see if we're in GC mode.
After any of these calls, it is not safe to switch modes.
Added a really ugly hack so that the ABI versions of the three .m files are not checked. This will (hopefully!) prevent the GC being enabled when libobjc is loaded after being compiled with -fobjc-gc.
- __strong pointers, preventing objects from being freed
_ __weak pointers are automatically freed when the last remaining __strong pointer goes away
- objc_gc_{retain,release}_np() functions, which can be used to implement CFRetain() and CFRelease() (adds an reference count - the object will not be collected until after its last retain is gone.
David Chisnall
theraven