From 96c51a8de18ee0675f48a98649fe25175c6b36f8 Mon Sep 17 00:00:00 2001
From: Owen Anderson <resistor@mac.com>
Date: Sat, 20 Jun 2009 00:32:27 +0000
Subject: [PATCH] Workaround for an... interesting bug in Darwin's
 pthread_rwlock_init.

llvm-svn: 73806
---
 llvm/lib/System/RWMutex.cpp | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/llvm/lib/System/RWMutex.cpp b/llvm/lib/System/RWMutex.cpp
index cf1aea03ddf3..15d98cb8f418 100644
--- a/llvm/lib/System/RWMutex.cpp
+++ b/llvm/lib/System/RWMutex.cpp
@@ -13,6 +13,7 @@
 
 #include "llvm/Config/config.h"
 #include "llvm/System/RWMutex.h"
+#include <cstring>
 
 //===----------------------------------------------------------------------===//
 //=== WARNING: Implementation here must contain only TRULY operating system
@@ -64,6 +65,12 @@ RWMutexImpl::RWMutexImpl()
     // Declare the pthread_rwlock data structures
     pthread_rwlock_t* rwlock =
       static_cast<pthread_rwlock_t*>(malloc(sizeof(pthread_rwlock_t)));
+
+#ifdef __APPLE__
+    // Workaround a bug/mis-feature in Darwin's pthread_rwlock_init.
+    bzero(rwlock, sizeof(pthread_rwlock_t));
+#endif
+
     pthread_rwlockattr_t attr;
 
     // Initialize the rwlock attributes