GCC's dialect of C++
GCC's dialect of C++
Posted Mar 31, 2017 16:57 UTC (Fri) by smckay (guest, #103253)In reply to: GCC's dialect of C++ by roc
Parent article: GCC for new contributors
When Apple says ARC they mean automatic refcounting, with the compiler calling retain/release instead of the programmer. It's actually their second attempt at eliminating manual refcounting; first there was a GC mode of the ObjC runtime, which was swiftly deprecated and I don't think even exists anymore. Going by https://clang.llvm.org/docs/AutomaticReferenceCounting.html, atomic ops are used for weak references but not otherwise. Section 6 specifically calls out that using atomic ops pervasively would kill performance.
Posted Apr 6, 2017 1:22 UTC (Thu)
by nix (subscriber, #2304)
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GCC's dialect of C++
AIUI, frequently the refcounts are eliminated entirely -- which is a good thing, because a refcount change is a memory write, and memory writes are comparatively expensive these days (particularly but not only for cross-core-shared things).