[PATCH] D31007: [Objective-C] Miscellaneous -fobjc-weak Fixes

[John McCall via Phabricator via cfe-commits]

rjmccall added inline comments.


================
Comment at: lib/Sema/SemaInit.cpp:6681
       // full-expression's cleanups.
-      if ((S.getLangOpts().ObjCAutoRefCount &&
-           MTE->getType()->isObjCLifetimeType()) ||
+      if (MTE->getType()->isNonTrivialObjCLifetimeType() ||
           (MTE->getStorageDuration() == SD_Automatic &&
----------------
Oh, I see what's happening here.  The special case for ARC is actually wholly unnecessary.  The code's been written as if MTE->getType() for an ARC temporary will just have type "id".  In fact, it'll have a lifetime-qualified type, dependent on the type of the reference which has been bound to it.  So we need to mark that there's a temporary cleanup if the type has non-trivial lifetime, i.e. if MTE->getType().hasNonTrivialObjCLifetime(); but this is already considered as part of MTE->getType().isDestructedType(), and the storage-duration condition there is correct as well.  So really we should just delete this entire clause.

That should eliminate the need for Type::isNonTrivialObjCLifetimeType().  In general, we don't want methods like that to ever exist: lifetime is determined by qualifiers, and querying a Type instead of a QualType has the potential to implicitly remove qualifiers.


https://reviews.llvm.org/D31007