2 files changed, 9 insertions, 10 deletions
diff --git a/clang/lib/Frontend/CreateInvocationFromCommandLine.cpp b/clang/lib/Frontend/CreateInvocationFromCommandLine.cpp
index 2d4c40f8b9f..3a5e1e8b15e 100644
--- a/clang/lib/Frontend/CreateInvocationFromCommandLine.cpp
+++ b/clang/lib/Frontend/CreateInvocationFromCommandLine.cpp
@@ -11,17 +11,18 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "clang/Frontend/Utils.h"
 #include "clang/Basic/DiagnosticOptions.h"
+#include "clang/Driver/Action.h"
 #include "clang/Driver/Compilation.h"
 #include "clang/Driver/Driver.h"
-#include "clang/Driver/Action.h"
 #include "clang/Driver/Options.h"
 #include "clang/Driver/Tool.h"
 #include "clang/Frontend/CompilerInstance.h"
 #include "clang/Frontend/FrontendDiagnostic.h"
+#include "clang/Frontend/Utils.h"
 #include "llvm/Option/ArgList.h"
 #include "llvm/Support/Host.h"
+#include "llvm/Support/Path.h"
 using namespace clang;
 using namespace llvm::opt;
 
@@ -102,5 +103,8 @@ std::unique_ptr<CompilerInvocation> clang::createInvocationFromCommandLine(
                                      CCArgs.size(),
                                      *Diags))
     return nullptr;
+  // Patch up the install dir, so we find the same standard library as the
+  // original compiler on MacOS.
+  CI->getHeaderSearchOpts().InstallDir = TheDriver.getInstalledDir();
   return CI;
 }
diff --git a/clang/lib/Frontend/InitHeaderSearch.cpp b/clang/lib/Frontend/InitHeaderSearch.cpp
index deedb22f3e1..2f62ad3faf6 100644
--- a/clang/lib/Frontend/InitHeaderSearch.cpp
+++ b/clang/lib/Frontend/InitHeaderSearch.cpp
@@ -476,14 +476,9 @@ void InitHeaderSearch::AddDefaultIncludePaths(const LangOptions &Lang,
       if (triple.isOSDarwin()) {
         // On Darwin, libc++ may be installed alongside the compiler in
         // include/c++/v1.
-        if (!HSOpts.ResourceDir.empty()) {
-          // Remove version from foo/lib/clang/version
-          StringRef NoVer = llvm::sys::path::parent_path(HSOpts.ResourceDir);
-          // Remove clang from foo/lib/clang
-          StringRef Lib = llvm::sys::path::parent_path(NoVer);
-          // Remove lib from foo/lib
-          SmallString<128> P = llvm::sys::path::parent_path(Lib);
-
+        if (!HSOpts.InstallDir.empty()) {
+          // Get from foo/bin to foo.
+          SmallString<128> P(llvm::sys::path::parent_path(HSOpts.InstallDir));
           // Get foo/include/c++/v1
           llvm::sys::path::append(P, "include", "c++", "v1");
           AddUnmappedPath(P, CXXSystem, false);