1 files changed, 27 insertions, 7 deletions
diff --git a/llvm/lib/Support/Unix/Path.inc b/llvm/lib/Support/Unix/Path.inc
index 0f61e94145e..8f98dda52d7 100644
--- a/llvm/lib/Support/Unix/Path.inc
+++ b/llvm/lib/Support/Unix/Path.inc
@@ -179,14 +179,34 @@ std::string getMainExecutable(const char *argv0, void *MainAddr) {
   char exe_path[MAXPATHLEN];
   StringRef aPath("/proc/self/exe");
   if (sys::fs::exists(aPath)) {
-      // /proc is not always mounted under Linux (chroot for example).
-      ssize_t len = readlink(aPath.str().c_str(), exe_path, sizeof(exe_path));
-      if (len >= 0)
-          return std::string(exe_path, len);
+    // /proc is not always mounted under Linux (chroot for example).
+    ssize_t len = readlink(aPath.str().c_str(), exe_path, sizeof(exe_path));
+    if (len < 0)
+      return "";
+
+    // Null terminate the string for realpath. readlink never null
+    // terminates its output.
+    len = std::min(len, long(sizeof(exe_path) - 1));
+    exe_path[len] = '\0';
+
+    // At least on GNU/Hurd, /proc/self/exe is a symlink to the path that
+    // was used to start the program, and not the eventual binary file.
+    // We thus needs to run realpath over it to get the actual place
+    // where llvm was installed.
+#if _POSIX_VERSION >= 200112 || defined(__GLIBC__)
+    char *real_path = realpath(exe_path, NULL);
+    std::string ret = std::string(real_path);
+    free(real_path);
+    return ret;
+#else
+    char real_path[MAXPATHLEN];
+    realpath(exe_path, real_path);
+    return std::string(real_path);
+#endif
   } else {
-      // Fall back to the classical detection.
-      if (getprogpath(exe_path, argv0))
-        return exe_path;
+    // Fall back to the classical detection.
+    if (getprogpath(exe_path, argv0))
+      return exe_path;
   }
 #elif defined(HAVE_DLFCN_H) && defined(HAVE_DLADDR)
   // Use dladdr to get executable path if available.