Vendor import of llvm RELEASE_350/final tag r216957 (effectively, 3.5.0 release):

https://llvm.org/svn/llvm-project/llvm/tags/RELEASE_350/final@216957

1 files changed, 14 insertions, 6 deletions

diff --git a/lib/Support/Unix/RWMutex.inc b/lib/Support/Unix/RWMutex.inc
index 40e87ff..edcbd52 100644
--- a/lib/Support/Unix/RWMutex.inc
+++ b/lib/Support/Unix/RWMutex.inc
@@ -16,28 +16,36 @@
 //===          is guaranteed to work on *all* UNIX variants.
 //===----------------------------------------------------------------------===//
 
+#include "llvm/Support/Mutex.h"
+
 namespace llvm {
 
 using namespace sys;
 
-RWMutexImpl::RWMutexImpl() { }
+// This naive implementation treats readers the same as writers.  This
+// will therefore deadlock if a thread tries to acquire a read lock
+// multiple times.
+
+RWMutexImpl::RWMutexImpl() : data_(new Mutex(false)) { }
 
-RWMutexImpl::~RWMutexImpl() { }
+RWMutexImpl::~RWMutexImpl() {
+  delete static_cast<Mutex *>(data_);
+}
 
 bool RWMutexImpl::reader_acquire() {
-  return true;
+  return static_cast<Mutex *>(data_)->acquire();
 }
 
 bool RWMutexImpl::reader_release() {
-  return true;
+  return static_cast<Mutex *>(data_)->release();
 }
 
 bool RWMutexImpl::writer_acquire() {
-  return true;
+  return static_cast<Mutex *>(data_)->acquire();
 }
 
 bool RWMutexImpl::writer_release() {
-  return true;
+  return static_cast<Mutex *>(data_)->release();
 }
 
 }