diff --git a/llvm/test/tools/llvm-ar/response-utf8.test b/llvm/test/tools/llvm-ar/response-utf8.test
new file mode 100644
--- /dev/null
+++ b/llvm/test/tools/llvm-ar/response-utf8.test
@@ -0,0 +1,11 @@
+## Check that response files can cope with non-ascii characters.
+
+# RUN: echo 'contents' > %t-£.txt
+
+# RUN: rm -f %t-£.a
+# RUN: echo 'r %t-£.a %t-£.txt' > %t-replace.txt
+# RUN: llvm-ar @%t-replace.txt
+
+# RUN: echo 'p %t-£.a %t-£.txt' > %t-print.txt
+# RUN: llvm-ar @%t-print.txt | FileCheck %s
+# CHECK: contents
diff --git a/llvm/test/tools/llvm-ar/response.test b/llvm/test/tools/llvm-ar/response.test
new file mode 100644
--- /dev/null
+++ b/llvm/test/tools/llvm-ar/response.test
@@ -0,0 +1,34 @@
+## llvm-ar should be able to consume response files.
+
+# RUN: echo 'contents' > %t.txt
+# RUN: echo 'rc %t1.a %t.txt' > %t.response1.txt
+# RUN: llvm-ar @%t.response1.txt
+# RUN: llvm-ar p %t1.a | FileCheck %s --check-prefix=CONTENTS
+
+## Quotes and Spaces.
+# RUN: echo 'contents' > '%t space.txt'
+## Python is used here to ensure the quotes are written to the response file
+# RUN: %python -c "import os; open(r'%t.response2.txt', 'w').write(r'%t2.a \"%t space.txt\"'+ '\n')"
+# RUN: llvm-ar rc @%t.response2.txt
+# RUN: llvm-ar p %t2.a | FileCheck %s --check-prefix=CONTENTS
+
+## Arguments after the response file.
+# RUN: echo 'rc %t3.a' > %t.response3.txt
+# RUN: llvm-ar @%t.response3.txt %t.txt
+# RUN: llvm-ar p %t3.a | FileCheck %s --check-prefix=CONTENTS
+
+# CONTENTS: contents
+
+## rsp-quoting
+# RUN: not llvm-ar --rsp-quoting=foobar @%t.response1.txt 2>&1 | \
+# RUN:   FileCheck  %s --check-prefix=ERROR
+# ERROR: Invalid response file quoting style foobar
+
+# RUN: echo -e 'rc %/t.a blah\\foo' > %t-rsp.txt
+# RUN: not llvm-ar --rsp-quoting=windows @%t-rsp.txt 2>&1 | \
+# RUN:   FileCheck %s --check-prefix=WIN
+# WIN: error: blah\foo: {{[Nn]}}o such file or directory
+
+# RUN: not llvm-ar -rsp-quoting posix @%t-rsp.txt 2>&1 | \
+# RUN:   FileCheck %s --check-prefix=POSIX
+# POSIX: error: blahfoo: {{[Nn]}}o such file or directory
diff --git a/llvm/tools/llvm-ar/llvm-ar.cpp b/llvm/tools/llvm-ar/llvm-ar.cpp
--- a/llvm/tools/llvm-ar/llvm-ar.cpp
+++ b/llvm/tools/llvm-ar/llvm-ar.cpp
@@ -83,6 +83,9 @@
     =bsd                -   bsd
   --plugin=<string>     - ignored for compatibility
   -h --help             - display this help and exit
+  --rsp-quoting         - quoting style for response files
+    =posix              -   posix
+    =windows            -   windows
   --version             - print the version and exit
   @<file>               - read options from <file>
 
@@ -1096,61 +1099,105 @@
   return false;
 }
 
+static const char *matchFlagWithArg(StringRef Expected,
+                                    ArrayRef<const char *>::iterator &ArgIt,
+                                    ArrayRef<const char *> Args) {
+  StringRef Arg = *ArgIt;
+
+  if (Arg.startswith("--"))
+    Arg = Arg.substr(2);
+  else if (Arg.startswith("-"))
+    Arg = Arg.substr(1);
+
+  size_t len = Expected.size();
+  if (Arg == Expected) {
+    if (++ArgIt == Args.end())
+      fail(std::string(Expected) + " requires an argument");
+
+    return *ArgIt;
+  }
+  if (Arg.startswith(Expected) && Arg.size() > len && Arg[len] == '=')
+    return Arg.data() + len + 1;
+
+  return nullptr;
+}
+
+static cl::TokenizerCallback getRspQuoting(ArrayRef<const char *> ArgsArr) {
+  cl::TokenizerCallback Ret =
+      Triple(sys::getProcessTriple()).getOS() == Triple::Win32
+          ? cl::TokenizeWindowsCommandLine
+          : cl::TokenizeGNUCommandLine;
+
+  for (ArrayRef<const char *>::iterator ArgIt = ArgsArr.begin();
+       ArgIt != ArgsArr.end(); ++ArgIt) {
+    if (const char *Match = matchFlagWithArg("rsp-quoting", ArgIt, ArgsArr)) {
+      StringRef MatchRef = Match;
+      if (MatchRef == "posix")
+        Ret = cl::TokenizeGNUCommandLine;
+      else if (MatchRef == "windows")
+        Ret = cl::TokenizeWindowsCommandLine;
+      else
+        fail(std::string("Invalid response file quoting style ") + Match);
+    }
+  }
+
+  return Ret;
+}
+
 static int ar_main(int argc, char **argv) {
-  SmallVector<const char *, 0> Argv(argv, argv + argc);
+  SmallVector<const char *, 0> Argv(argv + 1, argv + argc);
   StringSaver Saver(Alloc);
-  cl::ExpandResponseFiles(Saver, cl::TokenizeGNUCommandLine, Argv);
-  for (size_t i = 1; i < Argv.size(); ++i) {
-    StringRef Arg = Argv[i];
-    const char *match = nullptr;
-    auto MatchFlagWithArg = [&](const char *expected) {
-      size_t len = strlen(expected);
-      if (Arg == expected) {
-        if (++i >= Argv.size())
-          fail(std::string(expected) + " requires an argument");
-        match = Argv[i];
-        return true;
-      }
-      if (Arg.startswith(expected) && Arg.size() > len && Arg[len] == '=') {
-        match = Arg.data() + len + 1;
-        return true;
-      }
-      return false;
-    };
-    if (handleGenericOption(Argv[i]))
+
+  cl::ExpandResponseFiles(Saver, getRspQuoting(makeArrayRef(argv, argc)), Argv);
+
+  ArrayRef<const char *> ArgsArr = makeArrayRef(argv, argc);
+
+  for (ArrayRef<const char *>::iterator ArgIt = Argv.begin();
+       ArgIt != Argv.end(); ++ArgIt) {
+    const char *Match = nullptr;
+
+    if (handleGenericOption(*ArgIt))
       return 0;
-    if (Arg == "--") {
-      for (; i < Argv.size(); ++i)
-        PositionalArgs.push_back(Argv[i]);
+    if (strcmp(*ArgIt, "--") == 0) {
+      ++ArgIt;
+      for (; ArgIt != Argv.end(); ++ArgIt)
+        PositionalArgs.push_back(*ArgIt);
       break;
     }
-    if (Arg[0] == '-') {
-      if (Arg.startswith("--"))
-        Arg = Argv[i] + 2;
+
+    if (*ArgIt[0] != '-') {
+      if (Options.empty())
+        Options += *ArgIt;
       else
-        Arg = Argv[i] + 1;
-      if (Arg == "M") {
-        MRI = true;
-      } else if (MatchFlagWithArg("format")) {
-        FormatType = StringSwitch<Format>(match)
-                         .Case("default", Default)
-                         .Case("gnu", GNU)
-                         .Case("darwin", DARWIN)
-                         .Case("bsd", BSD)
-                         .Default(Unknown);
-        if (FormatType == Unknown)
-          fail(std::string("Invalid format ") + match);
-      } else if (MatchFlagWithArg("plugin")) {
-        // Ignored.
-      } else {
-        Options += Argv[i] + 1;
-      }
-    } else if (Options.empty()) {
-      Options += Argv[i];
-    } else {
-      PositionalArgs.push_back(Argv[i]);
+        PositionalArgs.push_back(*ArgIt);
+      continue;
     }
+
+    if (strcmp(*ArgIt, "-M") == 0) {
+      MRI = true;
+      continue;
+    }
+
+    Match = matchFlagWithArg("format", ArgIt, Argv);
+    if (Match) {
+      FormatType = StringSwitch<Format>(Match)
+                       .Case("default", Default)
+                       .Case("gnu", GNU)
+                       .Case("darwin", DARWIN)
+                       .Case("bsd", BSD)
+                       .Default(Unknown);
+      if (FormatType == Unknown)
+        fail(std::string("Invalid format ") + Match);
+      continue;
+    }
+
+    if (matchFlagWithArg("plugin", ArgIt, Argv) ||
+        matchFlagWithArg("rsp-quoting", ArgIt, Argv))
+      continue;
+
+    Options += *ArgIt + 1;
   }
+
   ArchiveOperation Operation = parseCommandLine();
   return performOperation(Operation, nullptr);
 }