 +}
 + 
  #endif // LLVM_ON_WIN32
+Index: lib/Support/Windows/DynamicLibrary.inc
+===================================================================
+--- lib/Support/Windows/DynamicLibrary.inc	(revision 167609)
++++ lib/Support/Windows/DynamicLibrary.inc	(working copy)
+@@ -31,16 +31,8 @@
+  #pragma comment(lib, "dbghelp.lib")
+ #endif
+ 
+-namespace llvm {
+-using namespace sys;
++using namespace llvm;
+ 
+-//===----------------------------------------------------------------------===//
+-//=== WARNING: Implementation here must contain only Win32 specific code
+-//===          and must not be UNIX code.
+-//===----------------------------------------------------------------------===//
+-
+-static DenseSet<HMODULE> *OpenedHandles;
+-
+ extern "C" {
+ 
+   static BOOL CALLBACK ELM_Callback(WIN32_ELMCB_PCSTR ModuleName,
+@@ -63,49 +55,61 @@ extern "C" {
+ #endif
+         stricmp(ModuleName, "msvcrt20") != 0 &&
+         stricmp(ModuleName, "msvcrt40") != 0) {
+-      OpenedHandles->insert((HMODULE)ModuleBase);
++       OpenedHandles->insert((HMODULE)ModuleBase);
+     }
+     return TRUE;
+   }
+-}
++} // extern "C"
+ 
+-DynamicLibrary DynamicLibrary::getPermanentLibrary(const char *filename,
+-                                                   std::string *errMsg) {
+-  SmartScopedLock<true> lock(getMutex());
+-
+-  if (!filename) {
++void *OpenLibraryImpl(const char *Filename, std::string *ErrMsg) {
++  if (!Filename) {
+     // When no file is specified, enumerate all DLLs and EXEs in the process.
+     if (OpenedHandles == 0)
+-      OpenedHandles = new DenseSet<HMODULE>();
++      OpenedHandles = new DenseSet<void *>();
+ 
+     EnumerateLoadedModules(GetCurrentProcess(), ELM_Callback, 0);
+     // Dummy library that represents "search all handles".
+     // This is mostly to ensure that the return value still shows up as "valid".
+-    return DynamicLibrary(&OpenedHandles);
++    return &OpenedHandles;
+   }
+   
+-  HMODULE a_handle = LoadLibrary(filename);
++  HMODULE a_handle = LoadLibrary(Filename);
+ 
+   if (a_handle == 0) {
+-    MakeErrMsg(errMsg, std::string(filename) + ": Can't open : ");
+-    return DynamicLibrary();
++    MakeErrMsg(ErrMsg, std::string(Filename) + ": Can't open : ");
++    return NULL;
+   }
+ 
+-  if (OpenedHandles == 0)
+-    OpenedHandles = new DenseSet<HMODULE>();
++  return (void *)a_handle;
++}
+ 
+-  // If we've already loaded this library, FreeLibrary() the handle in order to
+-  // keep the internal refcount at +1.
+-  if (!OpenedHandles->insert(a_handle).second)
+-    FreeLibrary(a_handle);
++bool CloseLibraryImpl(void *DlHandle, std::string *ErrMsg) {
++  if (!FreeLibrary((HMODULE)DlHandle)) {
++    MakeErrMsg(ErrMsg, "Cannot free DLL: ");
++    return false;
++  }
++  return true;
++}
+ 
+-  return DynamicLibrary(a_handle);
++void *GetAddressOfSymbolImpl(void *DlHandle, const char *SymbolName,
++                             bool Global) {
++  if (DlHandle == &OpenedHandles) {
++    // Dummy library that represents "search all handles".
++    if (Global) {
++      // All libraries are already being searched, do not recurse.
++      return 0;
++    } else {
++      // Perform a global symbol search through all libraries.
++      DynamicLibrary::SearchForLibrarySymbol(SymbolName);
++    }
++  }
++  return (void *)(intptr_t) GetProcAddress((HMODULE)DlHandle, SymbolName);
+ }
+ 
+ // Stack probing routines are in the support library (e.g. libgcc), but we don't
+ // have dynamic linking on windows. Provide a hook.
+ #define EXPLICIT_SYMBOL(SYM)                    \
+-  extern "C" { extern void *SYM; }
++  extern "C" void *SYM;
+ #define EXPLICIT_SYMBOL2(SYMFROM, SYMTO) EXPLICIT_SYMBOL(SYMTO)
+ 
+ #include "explicit_symbols.inc"
+@@ -113,51 +117,13 @@ extern "C" {
+ #undef EXPLICIT_SYMBOL
+ #undef EXPLICIT_SYMBOL2
+ 
+-void* DynamicLibrary::SearchForAddressOfSymbol(const char* symbolName) {
+-  SmartScopedLock<true> Lock(getMutex());
++void PopulateSpecialSymbolsImpl(StringMap<void *>& SymMap) {
++#define EXPLICIT_SYMBOL(SYM)                    \
++  SymMap[#SYM] = &SYM;
++#define EXPLICIT_SYMBOL2(SYMFROM, SYMTO) EXPLICIT_SYMBOL(SYMTO)
+ 
+-  // First check symbols added via AddSymbol().
+-  if (ExplicitSymbols) {
+-    StringMap<void *>::iterator i = ExplicitSymbols->find(symbolName);
++#include "explicit_symbols.inc"
+ 
+-    if (i != ExplicitSymbols->end())
+-      return i->second;
+-  }
+-
+-  // Now search the libraries.
+-  if (OpenedHandles) {
+-    for (DenseSet<HMODULE>::iterator I = OpenedHandles->begin(),
+-         E = OpenedHandles->end(); I != E; ++I) {
+-      FARPROC ptr = GetProcAddress((HMODULE)*I, symbolName);
+-      if (ptr) {
+-        return (void *)(intptr_t)ptr;
+-      }
+-    }
+-  }
+-
+-  #define EXPLICIT_SYMBOL(SYM)                    \
+-    if (!strcmp(symbolName, #SYM)) return (void*)&SYM;
+-  #define EXPLICIT_SYMBOL2(SYMFROM, SYMTO)        \
+-    if (!strcmp(symbolName, #SYMFROM)) return (void*)&SYMTO;
+-
+-  {
+-    #include "explicit_symbols.inc"
+-  }
+-
+-  #undef EXPLICIT_SYMBOL
+-  #undef EXPLICIT_SYMBOL2
+-
+-  return 0;
++#undef EXPLICIT_SYMBOL
++#undef EXPLICIT_SYMBOL2
+ }
+-
+-
+-void *DynamicLibrary::getAddressOfSymbol(const char *symbolName) {
+-  if (!isValid())
+-    return NULL;
+-  if (Data == &OpenedHandles)
+-    return SearchForAddressOfSymbol(symbolName);
+-  return (void *)(intptr_t)GetProcAddress((HMODULE)Data, symbolName);
+-}
+-
+-
+-}
+Index: lib/Support/CMakeLists.txt
+===================================================================
+--- lib/Support/CMakeLists.txt	(revision 167609)
++++ lib/Support/CMakeLists.txt	(working copy)
+@@ -80,6 +80,7 @@ add_llvm_library(LLVMSupport
+   Threading.cpp
+   TimeValue.cpp
+   Valgrind.cpp
++  Unix/DynamicLibrary.inc
+   Unix/Host.inc
+   Unix/Memory.inc
+   Unix/Mutex.inc
 Index: lib/Support/SearchForAddressOfSpecialSymbol.cpp
 ===================================================================
 --- lib/Support/SearchForAddressOfSpecialSymbol.cpp	(revision 167609)

-  return DoSearch(symbolName);
-}
-}  // namespace llvm
Index: lib/Support/CMakeLists.txt
===================================================================
--- lib/Support/CMakeLists.txt	(revision 167609)
+++ lib/Support/CMakeLists.txt	(working copy)
@@ -80,6 +80,7 @@ add_llvm_library(LLVMSupport
   Threading.cpp
   TimeValue.cpp
   Valgrind.cpp
+  Unix/DynamicLibrary.inc
   Unix/Host.inc
   Unix/Memory.inc
   Unix/Mutex.inc
Index: lib/Support/Windows/DynamicLibrary.inc
===================================================================
--- lib/Support/Windows/DynamicLibrary.inc	(revision 167609)
+++ lib/Support/Windows/DynamicLibrary.inc	(working copy)
@@ -31,16 +31,8 @@
  #pragma comment(lib, "dbghelp.lib")
 #endif
 
-namespace llvm {
-using namespace sys;
+using namespace llvm;
 
-//===----------------------------------------------------------------------===//
-//=== WARNING: Implementation here must contain only Win32 specific code
-//===          and must not be UNIX code.
-//===----------------------------------------------------------------------===//
-
-static DenseSet<HMODULE> *OpenedHandles;
-
 extern "C" {
 
   static BOOL CALLBACK ELM_Callback(WIN32_ELMCB_PCSTR ModuleName,
@@ -63,49 +55,61 @@ extern "C" {
 #endif
         stricmp(ModuleName, "msvcrt20") != 0 &&
         stricmp(ModuleName, "msvcrt40") != 0) {
-      OpenedHandles->insert((HMODULE)ModuleBase);
+       OpenedHandles->insert((HMODULE)ModuleBase);
     }
     return TRUE;
   }
-}
+} // extern "C"
 
-DynamicLibrary DynamicLibrary::getPermanentLibrary(const char *filename,
-                                                   std::string *errMsg) {
-  SmartScopedLock<true> lock(getMutex());
-
-  if (!filename) {
+void *OpenLibraryImpl(const char *Filename, std::string *ErrMsg) {
+  if (!Filename) {
     // When no file is specified, enumerate all DLLs and EXEs in the process.
     if (OpenedHandles == 0)
-      OpenedHandles = new DenseSet<HMODULE>();
+      OpenedHandles = new DenseSet<void *>();
 
     EnumerateLoadedModules(GetCurrentProcess(), ELM_Callback, 0);
     // Dummy library that represents "search all handles".
     // This is mostly to ensure that the return value still shows up as "valid".
-    return DynamicLibrary(&OpenedHandles);
+    return &OpenedHandles;
   }
   
-  HMODULE a_handle = LoadLibrary(filename);
+  HMODULE a_handle = LoadLibrary(Filename);
 
   if (a_handle == 0) {
-    MakeErrMsg(errMsg, std::string(filename) + ": Can't open : ");
-    return DynamicLibrary();
+    MakeErrMsg(ErrMsg, std::string(Filename) + ": Can't open : ");
+    return NULL;
   }
 
-  if (OpenedHandles == 0)
-    OpenedHandles = new DenseSet<HMODULE>();
+  return (void *)a_handle;
+}
 
-  // If we've already loaded this library, FreeLibrary() the handle in order to
-  // keep the internal refcount at +1.
-  if (!OpenedHandles->insert(a_handle).second)
-    FreeLibrary(a_handle);
+bool CloseLibraryImpl(void *DlHandle, std::string *ErrMsg) {
+  if (!FreeLibrary((HMODULE)DlHandle)) {
+    MakeErrMsg(ErrMsg, "Cannot free DLL: ");
+    return false;
+  }
+  return true;
+}
 
-  return DynamicLibrary(a_handle);
+void *GetAddressOfSymbolImpl(void *DlHandle, const char *SymbolName,
+                             bool Global) {
+  if (DlHandle == &OpenedHandles) {
+    // Dummy library that represents "search all handles".
+    if (Global) {
+      // All libraries are already being searched, do not recurse.
+      return 0;
+    } else {
+      // Perform a global symbol search through all libraries.
+      DynamicLibrary::SearchForLibrarySymbol(SymbolName);
+    }
+  }
+  return (void *)(intptr_t) GetProcAddress((HMODULE)DlHandle, SymbolName);
 }
 
 // Stack probing routines are in the support library (e.g. libgcc), but we don't
 // have dynamic linking on windows. Provide a hook.
 #define EXPLICIT_SYMBOL(SYM)                    \
-  extern "C" { extern void *SYM; }
+  extern "C" void *SYM;
 #define EXPLICIT_SYMBOL2(SYMFROM, SYMTO) EXPLICIT_SYMBOL(SYMTO)
 
 #include "explicit_symbols.inc"
@@ -113,51 +117,13 @@ extern "C" {
 #undef EXPLICIT_SYMBOL
 #undef EXPLICIT_SYMBOL2
 
-void* DynamicLibrary::SearchForAddressOfSymbol(const char* symbolName) {
-  SmartScopedLock<true> Lock(getMutex());
+void PopulateSpecialSymbolsImpl(StringMap<void *>& SymMap) {
+#define EXPLICIT_SYMBOL(SYM)                    \
+  SymMap[#SYM] = &SYM;
+#define EXPLICIT_SYMBOL2(SYMFROM, SYMTO) EXPLICIT_SYMBOL(SYMTO)
 
-  // First check symbols added via AddSymbol().
-  if (ExplicitSymbols) {
-    StringMap<void *>::iterator i = ExplicitSymbols->find(symbolName);
+#include "explicit_symbols.inc"
 
-    if (i != ExplicitSymbols->end())
-      return i->second;
-  }
-
-  // Now search the libraries.
-  if (OpenedHandles) {
-    for (DenseSet<HMODULE>::iterator I = OpenedHandles->begin(),
-         E = OpenedHandles->end(); I != E; ++I) {
-      FARPROC ptr = GetProcAddress((HMODULE)*I, symbolName);
-      if (ptr) {
-        return (void *)(intptr_t)ptr;
-      }
-    }
-  }
-
-  #define EXPLICIT_SYMBOL(SYM)                    \
-    if (!strcmp(symbolName, #SYM)) return (void*)&SYM;
-  #define EXPLICIT_SYMBOL2(SYMFROM, SYMTO)        \
-    if (!strcmp(symbolName, #SYMFROM)) return (void*)&SYMTO;
-
-  {
-    #include "explicit_symbols.inc"
-  }
-
-  #undef EXPLICIT_SYMBOL
-  #undef EXPLICIT_SYMBOL2
-
-  return 0;
+#undef EXPLICIT_SYMBOL
+#undef EXPLICIT_SYMBOL2
 }
-
-
-void *DynamicLibrary::getAddressOfSymbol(const char *symbolName) {
-  if (!isValid())
-    return NULL;
-  if (Data == &OpenedHandles)
-    return SearchForAddressOfSymbol(symbolName);
-  return (void *)(intptr_t)GetProcAddress((HMODULE)Data, symbolName);
-}
-
-
-}

     /// This functions permanently adds the symbol \p symbolName with the
     /// value \p symbolValue.  These symbols are searched before any
     /// libraries.
Index: lib/Support/Unix/DynamicLibrary.inc
===================================================================
--- lib/Support/Unix/DynamicLibrary.inc	(revision 0)
+++ lib/Support/Unix/DynamicLibrary.inc	(revision 0)
@@ -0,0 +1,118 @@
+//===--- Unix/DynamicLibrary.cpp - Unix DL Implementation -------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file provides the dlsym specific implementation of DynamicLibrary.
+//
+//===----------------------------------------------------------------------===//
+
+#include <dlfcn.h>
+
+static void MakeDlErrMsg(std::string *ErrMsg) {
+  if (ErrMsg) {
+    *ErrMsg = dlerror();
+  } else {
+    // Flush error state whether or not ErrMsg is provided.
+    dlerror();
+  }
+}
+
+void *OpenLibraryImpl(const char *Filename, std::string *ErrMsg) {
+  void *Handle = dlopen(Filename, RTLD_LAZY|RTLD_GLOBAL);
+  if (Handle == 0) {
+    MakeDlErrMsg(ErrMsg);
+    return NULL;
+  }
+
+#ifdef __CYGWIN__
+  // Cygwin searches symbols only in the main
+  // with the handle of dlopen(NULL, RTLD_GLOBAL).
+  if (Filename == NULL)
+    Handle = RTLD_DEFAULT;
+#endif
+  return Handle;
+}
+
+bool CloseLibraryImpl(void *DlHandle, std::string *ErrMsg) {
+  if (dlclose(DlHandle)) {
+    MakeDlErrMsg(ErrMsg);
+    return false;
+  }
+  return true;
+}
+
+void *GetAddressOfSymbolImpl(void *DlHandle, const char *SymbolName,
+                             bool /*Global*/) {
+  return dlsym(DlHandle, SymbolName);
+}
+
+#include <string.h>
+
+// Must declare the symbols in the global namespace.
+void PopulateSpecialSymbolsImpl(StringMap<void *>& SymMap) {
+// This macro returns the address of a well-known, explicit symbol
+#define EXPLICIT_SYMBOL(SYM) \
+    SymMap[#SYM] = &SYM
+
+// On linux we have a weird situation. The stderr/out/in symbols are both
+// macros and global variables because of standards requirements. So, we
+// boldly use the EXPLICIT_SYMBOL macro without checking for a #define first.
+#if defined(__linux__) and !defined(__ANDROID__)
+  {
+    EXPLICIT_SYMBOL(stderr);
+    EXPLICIT_SYMBOL(stdout);
+    EXPLICIT_SYMBOL(stdin);
+  }
+#else
+  // For everything else, we want to check to make sure the symbol isn't defined
+  // as a macro before using EXPLICIT_SYMBOL.
+  {
+#ifndef stdin
+    EXPLICIT_SYMBOL(stdin);
+#endif
+#ifndef stdout
+    EXPLICIT_SYMBOL(stdout);
+#endif
+#ifndef stderr
+    EXPLICIT_SYMBOL(stderr);
+#endif
+  }
+#endif
+#undef EXPLICIT_SYMBOL
+
+#define EXPLICIT_SYMBOL(SYM) \
+   extern "C" void *SYM; symMap[#SYM] = &SYM
+
+  // If this is darwin, it has some funky issues, try to solve them here.  Some
+  // important symbols are marked 'private external' which doesn't allow
+  // SearchForAddressOfSymbol to find them.  As such, we special case them here,
+  // there is only a small handful of them.
+
+#ifdef __APPLE__
+  {
+    // __eprintf is sometimes used for assert() handling on x86.
+    //
+    // FIXME: Currently disabled when using Clang, as we don't always have our
+    // runtime support libraries available.
+#ifndef __clang__
+#ifdef __i386__
+    EXPLICIT_SYMBOL(__eprintf);
+#endif
+#endif
+  }
+#endif
+
+#ifdef __CYGWIN__
+  {
+    EXPLICIT_SYMBOL(_alloca);
+    EXPLICIT_SYMBOL(__main);
+  }
+#endif
+
+#undef EXPLICIT_SYMBOL
+}
Index: lib/Support/DynamicLibrary.cpp
===================================================================
--- lib/Support/DynamicLibrary.cpp	(revision 167609)
