czhang marked 2 inline comments as done.
czhang added inline comments.

================
Comment at: 
clang-tools-extra/test/clang-tidy/bugprone-dynamic-static-initializers.hpp:33-35
+  // This may work fine when optimization is enabled because bar() can
+  // be turned into a constant 7.  But without optimization, it can
+  // cause problems. Therefore, we must err on the side of conservatism.
----------------
aaron.ballman wrote:
> czhang wrote:
> > aaron.ballman wrote:
> > > What problems can be caused here? Typically, dynamic init is only 
> > > problematic when it happens before main() is executed (because of 
> > > initialization order dependencies), but that doesn't apply to local 
> > > statics.
> > Consider the case when synchronization is disabled for static 
> > initialization, and two threads call `foo2` for the first time. It may be 
> > the case that they both try and initialize the static variable at the same 
> > time with different values (since the dynamic initializer may not be pure), 
> > creating a race condition.
> > Consider the case when synchronization is disabled for static initialization
> 
> This is a compiler bug, though: http://eel.is/c++draft/stmt.dcl#4.sentence-3
Sorry, I guess I didn't make it clear enough in the rst documentation file, but 
this check is for those who explicitly enable the -fno-threadsafe-statics flag 
because they provide their own synchronization. Then they would like to check 
if the headers they didn't write may possibly run into this issue when 
compiling with this flag.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D62829/new/

https://reviews.llvm.org/D62829



_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits

Reply via email to