Add my abstracted dynamic linker support files.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@9008 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Support/DynamicLinker.cpp b/lib/Support/DynamicLinker.cpp
new file mode 100644
index 0000000..7c52d3b
--- /dev/null
+++ b/lib/Support/DynamicLinker.cpp
@@ -0,0 +1,42 @@
+//===-- DynamicLinker.cpp - Implement DynamicLinker interface -------------===//
+//
+// Lightweight interface to dynamic library linking and loading, and dynamic
+// symbol lookup functionality, in whatever form the operating system
+// provides it.
+//
+// Possible future extensions include support for the HPUX shl_load()
+// interface, the Mac OS X NSLinkModule() interface, and the Windows
+// LoadLibrary() interface.
+//
+// Note that we assume that if dlopen() is available, then dlsym() is too.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Support/DynamicLinker.h"
+#include "Config/dlfcn.h"
+#include <cassert>
+
+bool LinkDynamicObject (const char *filename, std::string *ErrorMessage) {
+#if defined (HAVE_DLOPEN)
+  if (dlopen (filename, RTLD_NOW | RTLD_GLOBAL) == 0) {
+    if (ErrorMessage) *ErrorMessage = dlerror ();
+    return true;
+  }
+  return false;
+#else
+  assert (0 && "Dynamic object linking not implemented for this platform");
+#endif
+}
+
+void *GetAddressOfSymbol (const char *symbolName) {
+#if defined (HAVE_DLOPEN)
+  return dlsym (RTLD_DEFAULT, symbolName);
+#else
+  assert (0 && "Dynamic symbol lookup not implemented for this platform");
+#endif
+}
+
+// soft, cushiony C++ interface.
+void *GetAddressOfSymbol (const std::string &symbolName) {
+  return GetAddressOfSymbol (symbolName.c_str ());
+}