[PATCH] D52251: [builtins] Add __emutls_unregister_key function

[Yi Kong via Phabricator via llvm-commits]

kongyi marked an inline comment as done.
kongyi added inline comments.


================
Comment at: lib/builtins/emutls.c:397
+void __emutls_unregister_key(void) {
+    pthread_key_delete(emutls_pthread_key);
+}
----------------
chh wrote:
> rprichard wrote:
> > kongyi wrote:
> > > chh wrote:
> > > > Shouldn't this be called only after the pthread key was created?
> > > > gcc's version has a flag emutls_key_created set only after emutls_init.
> > > > 
> > > > 
> > > We don't need to check this, since emutls_key_delete is not expensive to call and we can safely ignore failure from it.
> > This code assumes that a zeroed pthread_key_t is never valid. I suspect that's true for Bionic? I confirmed it on aosp-master and KitKat. For the NDK's purposes, it needs to be true for android-16 and up.
> > 
> > It's apparently not generally true? http://www.tekkotsu.org/cvslog2web/2009/03/commit-1236808823.html
> > 
> My concern is run time error or crash in calls to pthread_key_delete(0).
> That might not happen with bionic, but i think the behavior is undefined in POSIX and could happen in other platforms.
> I know some other platforms already depend on this emutls.c.
> Maybe they have not seen the dlclose issue yet, but it would be nice to make this function work for general cases.
> 
Changed to only call pthread_key_delete if key is created.


Repository:
  rCRT Compiler Runtime

https://reviews.llvm.org/D52251