Index: lldb/source/Host/macosx/objcxx/HostInfoMacOSX.mm
===================================================================
--- lldb/source/Host/macosx/objcxx/HostInfoMacOSX.mm
+++ lldb/source/Host/macosx/objcxx/HostInfoMacOSX.mm
@@ -373,26 +373,18 @@
 static std::string GetXcodeSDK(XcodeSDK sdk) {
   XcodeSDK::Info info = sdk.Parse();
   std::string sdk_name = XcodeSDK::GetCanonicalName(info);
-  auto find_sdk = [](std::string sdk_name) -> std::string {
-    std::string xcrun_cmd;
-    std::string developer_dir = GetEnvDeveloperDir();
-    if (developer_dir.empty())
-      if (FileSpec fspec = HostInfo::GetShlibDir())
-        if (FileSystem::Instance().Exists(fspec)) {
-          FileSpec path(
-              XcodeSDK::FindXcodeContentsDirectoryInPath(fspec.GetPath()));
-          if (path.RemoveLastPathComponent())
-            developer_dir = path.GetPath();
-        }
+
+  auto xcrun = [](std::string developer_dir, std::string sdk) -> std::string {
+    std::string xcrun_cmd = "xcrun --show-sdk-path --sdk " + sdk;
     if (!developer_dir.empty())
-      xcrun_cmd = "/usr/bin/env DEVELOPER_DIR=\"" + developer_dir + "\" ";
-    xcrun_cmd += "xcrun --show-sdk-path --sdk " + sdk_name;
+      xcrun_cmd =
+          "/usr/bin/env DEVELOPER_DIR=\"" + developer_dir + "\" " + xcrun_cmd;
 
     int status = 0;
     int signo = 0;
     std::string output_str;
     lldb_private::Status error =
-        Host::RunShellCommand(xcrun_cmd.c_str(), FileSpec(), &status, &signo,
+        Host::RunShellCommand(xcrun_cmd, FileSpec(), &status, &signo,
                               &output_str, std::chrono::seconds(15));
 
     // Check that xcrun return something useful.
@@ -414,6 +406,32 @@
     return output.str();
   };
 
+  auto find_sdk = [&](std::string sdk_name) -> std::string {
+    // Invoke xcrun with the developer dir specified in the environment.
+    std::string developer_dir = GetEnvDeveloperDir();
+    if (!developer_dir.empty()) {
+      // Don't fallback if DEVELOPER_DIR was set.
+      return xcrun(developer_dir, sdk_name);
+    }
+
+    // Invoke xcrun with the shlib dir.
+    if (FileSpec fspec = HostInfo::GetShlibDir()) {
+      if (FileSystem::Instance().Exists(fspec)) {
+        FileSpec path(
+            XcodeSDK::FindXcodeContentsDirectoryInPath(fspec.GetPath()));
+        if (path.RemoveLastPathComponent()) {
+          developer_dir = path.GetPath();
+          std::string sdk = xcrun(developer_dir, sdk_name);
+          if (!sdk.empty())
+            return sdk;
+        }
+      }
+    }
+
+    // Invoke xcrun without a developer dir as a last resort.
+    return xcrun("", sdk_name);
+  };
+
   std::string path = find_sdk(sdk_name);
   while (path.empty()) {
     // Try an alternate spelling of the name ("macosx10.9internal").