Revamp llvm::once_flag to be closer to std::once_flag

Summary:
Make this interface reusable similarly to std::call_once and std::once_flag interface.

This makes porting LLDB to NetBSD easier as there was in the original approach a portable way to specify a non-static once_flag. With this change translating std::once_flag to llvm::once_flag is mechanical.

Sponsored by <The NetBSD Foundation>

Reviewers: mehdi_amini, labath, joerg

Reviewed By: mehdi_amini

Subscribers: emaste, clayborg

Differential Revision: https://reviews.llvm.org/D29566

llvm-svn: 294143

1 files changed, 1 insertions, 1 deletions

diff --git a/llvm/lib/Support/ManagedStatic.cpp b/llvm/lib/Support/ManagedStatic.cpp
index 7dd31315f90..fb7cd070c42 100644
--- a/llvm/lib/Support/ManagedStatic.cpp
+++ b/llvm/lib/Support/ManagedStatic.cpp
@@ -21,7 +21,7 @@ using namespace llvm;
 
 static const ManagedStaticBase *StaticList = nullptr;
 static sys::Mutex *ManagedStaticMutex = nullptr;
-LLVM_DEFINE_ONCE_FLAG(mutex_init_flag);
+static llvm::once_flag mutex_init_flag;
 
 static void initializeMutex() {
   ManagedStaticMutex = new sys::Mutex();