3 files changed, 35 insertions, 0 deletions
diff --git a/include/llvm/System/DynamicLibrary.h b/include/llvm/System/DynamicLibrary.h
index 5edbfd6f22..1aea0460a2 100644
--- a/include/llvm/System/DynamicLibrary.h
+++ b/include/llvm/System/DynamicLibrary.h
@@ -26,6 +26,9 @@ namespace sys {
   /// operating system interface, this class provides a portable interface that
   /// allows dynamic libraries to be loaded and and searched for externally
   /// defined symbols. This is typically used to provide "plug-in" support.
+  /// It also allows for symbols to be defined which don't live in any library,
+  /// but rather the main program itself, useful on Windows where the main
+  /// executable cannot be searched.
   /// @since 1.4
   /// @brief Portable dynamic library abstraction.
   class DynamicLibrary {
@@ -81,6 +84,17 @@ namespace sys {
         return SearchForAddressOfSymbol(symbolName.c_str());
       }
 
+      /// This functions permanently adds the symbol \p symbolName with the
+      /// value \p symbolValue.  These symbols are searched before any
+      /// libraries.
+      /// @brief Add searchable symbol/value pair.
+      static void AddSymbol(const char* symbolName, void *symbolValue);
+
+      /// @brief Convenience function for C++ophiles.
+      static void AddSymbol(const std::string& symbolName, void *symbolValue) {
+        AddSymbol(symbolName.c_str(), symbolValue);
+      }
+
     /// @}
     /// @name Accessors
     /// @{
diff --git a/lib/System/DynamicLibrary.cpp b/lib/System/DynamicLibrary.cpp
index 18894cbc87..0c179fc2f7 100644
--- a/lib/System/DynamicLibrary.cpp
+++ b/lib/System/DynamicLibrary.cpp
@@ -13,6 +13,14 @@
 
 #include "llvm/System/DynamicLibrary.h"
 #include "llvm/Config/config.h"
+#include <map>
+
+// Collection of symbol name/value pairs to be searched prior to any libraries.
+static std::map<std::string, void *> g_symbols;
+
+void llvm::sys::DynamicLibrary::AddSymbol(const char* symbolName, void *symbolValue) {
+  g_symbols[symbolName] = symbolValue;
+}
 
 // It is not possible to use ltdl.c on VC++ builds as the terms of its LGPL
 // license and special exception would cause all of LLVM to be placed under
@@ -107,6 +115,13 @@ void DynamicLibrary::LoadLibraryPermanently(const char* filename) {
 
 void* DynamicLibrary::SearchForAddressOfSymbol(const char* symbolName) {
   check_ltdl_initialization();
+
+  // First check symbols added via AddSymbol().
+  std::map<std::string, void *>::iterator I = g_symbols.find(symbolName);
+  if (I != g_symbols.end())
+    return I->second;
+
+  // Now search the libraries.
   for (std::vector<lt_dlhandle>::iterator I = OpenedHandles.begin(),
        E = OpenedHandles.end(); I != E; ++I) {
     lt_ptr ptr = lt_dlsym(*I, symbolName);
diff --git a/lib/System/Win32/DynamicLibrary.inc b/lib/System/Win32/DynamicLibrary.inc
index 1492138682..310d3dc835 100644
--- a/lib/System/Win32/DynamicLibrary.inc
+++ b/lib/System/Win32/DynamicLibrary.inc
@@ -107,6 +107,12 @@ void DynamicLibrary::LoadLibraryPermanently(const char* filename) {
 }
 
 void* DynamicLibrary::SearchForAddressOfSymbol(const char* symbolName) {
+  // First check symbols added via AddSymbol().
+  std::map<std::string, void *>::iterator I = g_symbols.find(symbolName);
+  if (I != g_symbols.end())
+    return I->second;
+
+  // Now search the libraries.
   for (std::vector<HMODULE>::iterator I = OpenedHandles.begin(),
        E = OpenedHandles.end(); I != E; ++I) {
     FARPROC ptr = GetProcAddress((HMODULE)*I, symbolName);