Index: llvm/trunk/lib/Support/Unix/Path.inc
===================================================================
--- llvm/trunk/lib/Support/Unix/Path.inc
+++ llvm/trunk/lib/Support/Unix/Path.inc
@@ -103,13 +103,16 @@
 #define STATVFS_F_FLAG(vfs) (vfs).f_flags
 #endif
 
+#if defined(__FreeBSD__) || defined(__NetBSD__)
+#include <sys/sysctl.h>
+#endif
+
 using namespace llvm;
 
 namespace llvm {
 namespace sys  {
 namespace fs {
-#if defined(__FreeBSD__) || defined (__NetBSD__) || defined(__Bitrig__) || \
-    defined(__OpenBSD__) || defined(__minix) || defined(__FreeBSD_kernel__) || \
+#if defined(__Bitrig__) || defined(__OpenBSD__) || defined(__minix) || \
     defined(__linux__) || defined(__CYGWIN__) || defined(__DragonFly__) || \
     defined(_AIX)
 static int
@@ -164,7 +167,7 @@
   free(pv);
   return nullptr;
 }
-#endif // __FreeBSD__ || __NetBSD__ || __FreeBSD_kernel__
+#endif // Bitrig || OpenBSD || minix || linux || CYGWIN || DragonFly || AIX
 
 /// GetMainExecutable - Return the path to the main executable, given the
 /// value of argv[0] from program startup.
@@ -180,9 +183,24 @@
     if (realpath(exe_path, link_path))
       return link_path;
   }
-#elif defined(__FreeBSD__) || defined (__NetBSD__) || defined(__Bitrig__) || \
-      defined(__OpenBSD__) || defined(__minix) || defined(__DragonFly__) || \
-      defined(__FreeBSD_kernel__) || defined(_AIX)
+#elif defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__NetBSD__)
+  int mib[4];
+  mib[0] = CTL_KERN;
+#if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
+  mib[1] = KERN_PROC;
+  mib[2] = KERN_PROC_PATHNAME;
+  mib[3] = -1;
+#else
+  mib[1] = KERN_PROC_ARGS;
+  mib[2] = -1;
+  mib[3] = KERN_PROC_PATHNAME;
+#endif
+  char exe_path[PATH_MAX];
+  size_t cb = sizeof(exe_path);
+  if (sysctl(mib, 4, exe_path, &cb, NULL, 0) == 0)
+    return exe_path;
+#elif defined(__Bitrig__) || defined(__OpenBSD__) || defined(__minix) || \
+      defined(__DragonFly__) || defined(_AIX)
   char exe_path[PATH_MAX];
 
   if (getprogpath(exe_path, argv0) != NULL)
Index: llvm/trunk/unittests/Support/DynamicLibrary/DynamicLibraryTest.cpp
===================================================================
--- llvm/trunk/unittests/Support/DynamicLibrary/DynamicLibraryTest.cpp
+++ llvm/trunk/unittests/Support/DynamicLibrary/DynamicLibraryTest.cpp
@@ -23,8 +23,10 @@
 extern "C" PIPSQUEAK_EXPORT const char *TestA() { return "ProcessCall"; }
 
 std::string LibPath() {
+  const std::vector<testing::internal::string>& Argvs = testing::internal::GetArgvs();
+  const char *Argv0 = Argvs.size() > 0 ? Argvs[0].c_str() : "DynamicLibraryTests";
   void *Ptr = (void*)(intptr_t)TestA;
-  std::string Path = fs::getMainExecutable("DynamicLibraryTests", Ptr);
+  std::string Path = fs::getMainExecutable(Argv0, Ptr);
   llvm::SmallString<256> Buf(path::parent_path(Path));
   path::append(Buf, "PipSqueak.so");
   return Buf.str();