Chandler Carruth dd1463823a This is yet another attempt to re-instate r220932 as discussed in ... D19271. Previous attempt was broken by NetBSD, so in this version I've made the fallback path generic rather than Windows specific and sent both Windows and NetBSD to it. I've also re-formatted the code some, and used an exact clone of the code in PassSupport.h for doing manual call-once using our atomics rather than rolling a new one. If this sticks, we can replace the fallback path for Windows with a Windows-specific implementation that is more reliable. Original commit message: This patch adds an llvm_call_once which is a wrapper around std::call_once on platforms where it is available and devoid of bugs. The patch also migrates the ManagedStatic mutex to be allocated using llvm_call_once. These changes are philosophically equivalent to the changes added in r219638, which were reverted due to a hang on Win32 which was the result of a bug in the Windows implementation of std::call_once. Differential Revision: http://reviews.llvm.org/D5922 llvm-svn: 271558		2016-06-02 18:22:12 +00:00
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llvm	This is yet another attempt to re-instate r220932 as discussed in	2016-06-02 18:22:12 +00:00
llvm-c	Extract renaming from D19181	2016-05-23 16:38:25 +00:00