Index: include/llvm/Support/Path.h
===================================================================
--- include/llvm/Support/Path.h
+++ include/llvm/Support/Path.h
@@ -325,6 +325,16 @@
 /// @result True if a home directory is set, false otherwise.
 bool home_directory(SmallVectorImpl<char> &result);
 
+/// @brief Get the user's cache directory.
+///
+/// Expect the resulting path to be a directory shared with other
+/// applications/services used by the user. At least an application/service name
+/// should be appended to the path before storing any files.
+///
+/// @param result Holds the resulting path.
+/// @result True if a cache directory path is set, false otherwise.
+bool user_cache_directory(SmallVectorImpl<char> &result);
+
 /// @brief Has root name?
 ///
 /// root_name != ""
Index: lib/Support/Unix/Path.inc
===================================================================
--- lib/Support/Unix/Path.inc
+++ lib/Support/Unix/Path.inc
@@ -560,6 +560,56 @@
   return false;
 }
 
+namespace {
+bool getDarwinConfDir(bool TempDir, SmallVectorImpl<char> &Result) {
+  #if defined(_CS_DARWIN_USER_TEMP_DIR) && defined(_CS_DARWIN_USER_CACHE_DIR)
+  // On Darwin, use DARWIN_USER_TEMP_DIR or DARWIN_USER_CACHE_DIR.
+  // macros defined in <unistd.h> on darwin >= 9
+  int ConfName = TempDir ? _CS_DARWIN_USER_TEMP_DIR
+                         : _CS_DARWIN_USER_CACHE_DIR;
+  size_t ConfLen = confstr(ConfName, nullptr, 0);
+  if (ConfLen > 0) {
+    do {
+      Result.resize(ConfLen);
+      ConfLen = confstr(ConfName, Result.data(), Result.size());
+    } while (ConfLen > 0 && ConfLen != Result.size());
+
+    if (ConfLen > 0) {
+      assert(Result.back() == 0);
+      Result.pop_back();
+      return true;
+    }
+
+    Result.clear();
+  }
+  #endif
+  return false;
+}
+}
+
+bool user_cache_directory(SmallVectorImpl<char> &result) {
+  // First try using XDS_CACHE_HOME env variable,
+  // as specified in XDG Base Directory Specification at
+  // http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html
+  if (const char *xdsCacheDir = std::getenv("XDS_CACHE_HOME")) {
+    result.clear();
+    result.append(xdsCacheDir, xdsCacheDir + strlen(xdsCacheDir));
+    return true;
+  }
+
+  // Try Darwin configuration query
+  if (getDarwinConfDir(false, result))
+    return true;
+
+  // Use "$HOME/.cache" if $HOME is available
+  if (home_directory(result)) {
+    append(result, ".cache");
+    return true;
+  }
+
+  return false;
+}
+
 static const char *getEnvTempDir() {
   // Check whether the temporary directory is specified by an environment
   // variable.
@@ -594,27 +644,8 @@
     }
   }
 
-#if defined(_CS_DARWIN_USER_TEMP_DIR) && defined(_CS_DARWIN_USER_CACHE_DIR)
-  // On Darwin, use DARWIN_USER_TEMP_DIR or DARWIN_USER_CACHE_DIR.
-  // macros defined in <unistd.h> on darwin >= 9
-  int ConfName = ErasedOnReboot? _CS_DARWIN_USER_TEMP_DIR
-                               : _CS_DARWIN_USER_CACHE_DIR;
-  size_t ConfLen = confstr(ConfName, nullptr, 0);
-  if (ConfLen > 0) {
-    do {
-      Result.resize(ConfLen);
-      ConfLen = confstr(ConfName, Result.data(), Result.size());
-    } while (ConfLen > 0 && ConfLen != Result.size());
-
-    if (ConfLen > 0) {
-      assert(Result.back() == 0);
-      Result.pop_back();
-      return;
-    }
-
-    Result.clear();
-  }
-#endif
+  if (getDarwinConfDir(ErasedOnReboot, Result))
+    return;
 
   const char *RequestedDir = getDefaultTempDir(ErasedOnReboot);
   Result.append(RequestedDir, RequestedDir + strlen(RequestedDir));
Index: lib/Support/Windows/Path.inc
===================================================================
--- lib/Support/Windows/Path.inc
+++ lib/Support/Windows/Path.inc
@@ -771,6 +771,10 @@
   return getKnownFolderPath(FOLDERID_Profile, result);
 }
 
+bool user_cache_directory(SmallVectorImpl<char> &result) {
+  return getKnownFolderPath(FOLDERID_LocalAppData, result);
+}
+
 static bool getTempDirEnvVar(const char *Var, SmallVectorImpl<char> &Res) {
   SmallVector<wchar_t, 128> NameUTF16;
   if (windows::UTF8ToUTF16(Var, NameUTF16))
Index: unittests/Support/Path.cpp
===================================================================
--- unittests/Support/Path.cpp
+++ unittests/Support/Path.cpp
@@ -322,6 +322,12 @@
   }
 }
 
+TEST(Support, UserCacheDirectory) {
+  SmallString<13> cacheDir;
+  auto status = path::user_cache_directory(cacheDir);
+  EXPECT_TRUE(status ^ cacheDir.empty());
+}
+
 class FileSystemTest : public testing::Test {
 protected:
   /// Unique temporary directory in which all created filesystem entities must