[PATCH] D19271: Change CALL_ONCE_INITIALIZATION implementation to use static initialization

[Mehdi AMINI via llvm-commits]

joker.eph added inline comments.

================
Comment at: include/llvm/PassSupport.h:35
@@ +34,3 @@
+#define CALL_ONCE_INITIALIZATION(function)                                     \
+  static bool init_once([&] {                                                  \
+    function(Registry);                                                        \
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kcc wrote:
> kcc wrote:
> > Mmm. I am probably missing something trivial (c++11-ish), but how is this going to work?
> > For me it looks like you define a static bool function, but never call it. 
> Aaaah, init_once is a bool variable, not a function. Oh, how much this is confusing... 
> Will this work with the versions of Visual C++ we use for LLVM? 
> I remember that static initialization was broken there (until recently?)
> 
> Why not std::call_once? 
Yeah it would deserve a comment probably :)
I don't know if static initialization is safe in MSVC 2013 (I know it was announced to be "fixed", but don't know which version).

`std::call_once` require `<mutex>`, and I was worried of portability (I had trouble last time I tried to include it), and because of that we have an abstraction of mutex in libSupport I believe). 



http://reviews.llvm.org/D19271