diff --git a/clang/lib/Driver/ToolChains/Darwin.cpp b/clang/lib/Driver/ToolChains/Darwin.cpp
--- a/clang/lib/Driver/ToolChains/Darwin.cpp
+++ b/clang/lib/Driver/ToolChains/Darwin.cpp
@@ -1141,25 +1141,38 @@
   SmallString<128> P(getDriver().ClangExecutable);
   llvm::sys::path::remove_filename(P); // 'clang'
   llvm::sys::path::remove_filename(P); // 'bin'
+  llvm::sys::path::append(P, "lib", "arc");
 
   // 'libarclite' usually lives in the same toolchain as 'clang'. However, the
   // Swift open source toolchains for macOS distribute Clang without libarclite.
   // In that case, to allow the linker to find 'libarclite', we point to the
   // 'libarclite' in the XcodeDefault toolchain instead.
-  if (getXcodeDeveloperPath(P).empty()) {
-    if (const Arg *A = Args.getLastArg(options::OPT_isysroot)) {
+  if (!getVFS().exists(P)) {
+    auto updatePath = [&](const Arg *A) {
       // Try to infer the path to 'libarclite' in the toolchain from the
       // specified SDK path.
       StringRef XcodePathForSDK = getXcodeDeveloperPath(A->getValue());
-      if (!XcodePathForSDK.empty()) {
-        P = XcodePathForSDK;
-        llvm::sys::path::append(P, "Toolchains/XcodeDefault.xctoolchain/usr");
-      }
+      if (XcodePathForSDK.empty())
+        return false;
+
+      P = XcodePathForSDK;
+      llvm::sys::path::append(P, "Toolchains/XcodeDefault.xctoolchain/usr",
+                              "lib", "arc");
+      return getVFS().exists(P);
+    };
+
+    bool updated = false;
+    if (const Arg *A = Args.getLastArg(options::OPT_isysroot))
+      updated = updatePath(A);
+
+    if (!updated) {
+      if (const Arg *A = Args.getLastArg(options::OPT__sysroot_EQ))
+        updatePath(A);
     }
   }
 
   CmdArgs.push_back("-force_load");
-  llvm::sys::path::append(P, "lib", "arc", "libarclite_");
+  llvm::sys::path::append(P, "libarclite_");
   // Mash in the platform.
   if (isTargetWatchOSSimulator())
     P += "watchsimulator";