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llvm-svn: 244337

1 files changed, 4 insertions, 0 deletions

diff --git a/llvm/lib/Support/CrashRecoveryContext.cpp b/llvm/lib/Support/CrashRecoveryContext.cpp
index b9829e1192a..352b519f9b4 100644
--- a/llvm/lib/Support/CrashRecoveryContext.cpp
+++ b/llvm/lib/Support/CrashRecoveryContext.cpp
@@ -24,6 +24,10 @@ static ManagedStatic<
     sys::ThreadLocal<const CrashRecoveryContextImpl> > CurrentContext;
 
 struct CrashRecoveryContextImpl {
+  // When threads are disabled, this links up all active
+  // CrashRecoveryContextImpls.  When threads are enabled there's one thread
+  // per CrashRecoveryContext and CurrentContext is a thread-local, so only one
+  // CrashRecoveryContextImpl is active per thread and this is always null.
   const CrashRecoveryContextImpl *Next;
 
   CrashRecoveryContext *CRC;