From 27cb5e612ae280a0084a2c608cc8b13786431b7d Mon Sep 17 00:00:00 2001
From: Owen Anderson <resistor@mac.com>
Date: Thu, 18 Nov 2010 18:49:05 +0000
Subject: [PATCH] Use thread-safe statics to avoid a static constructor here. 
 This isn't thread-safe on MSVC, but we don't support threaded LLVM there
 anyways.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119718 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/System/DynamicLibrary.cpp | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/lib/System/DynamicLibrary.cpp b/lib/System/DynamicLibrary.cpp
index 3da50a28b65..33f86334e38 100644
--- a/lib/System/DynamicLibrary.cpp
+++ b/lib/System/DynamicLibrary.cpp
@@ -61,9 +61,19 @@ using namespace llvm::sys;
 //===          independent code.
 //===----------------------------------------------------------------------===//
 
-static SmartMutex<true> HandlesMutex;
+static SmartMutex<true>* HandlesMutex;
 static std::vector<void *> *OpenedHandles = 0;
 
+static bool InitializeMutex() {
+  HandlesMutex = new SmartMutex<true>;
+  return HandlesMutex != 0;
+}
+
+static bool EnsureMutexInitialized() {
+  static bool result = InitializeMutex();
+  return result;
+}
+
 
 bool DynamicLibrary::LoadLibraryPermanently(const char *Filename,
                                             std::string *ErrMsg) {
@@ -78,7 +88,8 @@ bool DynamicLibrary::LoadLibraryPermanently(const char *Filename,
   if (Filename == NULL)
     H = RTLD_DEFAULT;
 #endif
-  SmartScopedLock<true> Lock(HandlesMutex);
+  EnsureMutexInitialized();
+  SmartScopedLock<true> Lock(*HandlesMutex);
   if (OpenedHandles == 0)
     OpenedHandles = new std::vector<void *>();
   OpenedHandles->push_back(H);
@@ -113,7 +124,8 @@ void* DynamicLibrary::SearchForAddressOfSymbol(const char* symbolName) {
 
 #if HAVE_DLFCN_H
   // Now search the libraries.
-  SmartScopedLock<true> Lock(HandlesMutex);
+  EnsureMutexInitialized();
+  SmartScopedLock<true> Lock(*HandlesMutex);
   if (OpenedHandles) {
     for (std::vector<void *>::iterator I = OpenedHandles->begin(),
          E = OpenedHandles->end(); I != E; ++I) {