From: Dan Gohman <gohman@apple.com>
Date: Thu, 24 Jun 2010 16:31:32 +0000 (+0000)
Subject: Add a comment about a thread safety issue in Statistic.h.
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=27da66db3e3d61e9320c8562d9504f939d884598;p=oota-llvm.git

Add a comment about a thread safety issue in Statistic.h.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106756 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/include/llvm/ADT/Statistic.h b/include/llvm/ADT/Statistic.h
index c593c58c127..3a1319f1090 100644
--- a/include/llvm/ADT/Statistic.h
+++ b/include/llvm/ADT/Statistic.h
@@ -56,6 +56,10 @@ public:
   }
   
   const Statistic &operator++() {
+    // FIXME: This function and all those that follow carefully use an
+    // atomic operation to update the value safely in the presence of
+    // concurrent accesses, but not to read the return value, so the
+    // return value is not thread safe.
     sys::AtomicIncrement(&Value);
     return init();
   }