Index: llvm/trunk/include/llvm/Support/FileSystem.h
===================================================================
--- llvm/trunk/include/llvm/Support/FileSystem.h
+++ llvm/trunk/include/llvm/Support/FileSystem.h
@@ -349,6 +349,12 @@
 std::error_code real_path(const Twine &path, SmallVectorImpl<char> &output,
                           bool expand_tilde = false);
 
+/// Expands ~ expressions to the user's home directory. On Unix ~user
+/// directories are resolved as well.
+///
+/// @param path The path to resolve.
+void expand_tilde(const Twine &path, SmallVectorImpl<char> &output);
+
 /// Get the current path.
 ///
 /// @param result Holds the current path on return.
Index: llvm/trunk/lib/Support/Unix/Path.inc
===================================================================
--- llvm/trunk/lib/Support/Unix/Path.inc
+++ llvm/trunk/lib/Support/Unix/Path.inc
@@ -550,6 +550,18 @@
   llvm::sys::path::append(Path, Storage);
 }
 
+
+void expand_tilde(const Twine &path, SmallVectorImpl<char> &dest) {
+  dest.clear();
+  if (path.isTriviallyEmpty())
+    return;
+
+  path.toVector(dest);
+  expandTildeExpr(dest);
+
+  return;
+}
+
 static file_type typeForMode(mode_t Mode) {
   if (S_ISDIR(Mode))
     return file_type::directory_file;
Index: llvm/trunk/lib/Support/Windows/Path.inc
===================================================================
--- llvm/trunk/lib/Support/Windows/Path.inc
+++ llvm/trunk/lib/Support/Windows/Path.inc
@@ -1253,6 +1253,17 @@
   Path.insert(Path.begin() + 1, HomeDir.begin() + 1, HomeDir.end());
 }
 
+void expand_tilde(const Twine &path, SmallVectorImpl<char> &dest) {
+  dest.clear();
+  if (path.isTriviallyEmpty())
+    return;
+
+  path.toVector(dest);
+  expandTildeExpr(dest);
+
+  return;
+}
+
 std::error_code real_path(const Twine &path, SmallVectorImpl<char> &dest,
                           bool expand_tilde) {
   dest.clear();
Index: llvm/trunk/unittests/Support/Path.cpp
===================================================================
--- llvm/trunk/unittests/Support/Path.cpp
+++ llvm/trunk/unittests/Support/Path.cpp
@@ -516,6 +516,8 @@
   EXPECT_EQ(Expected, Actual);
 
   SmallString<64> HomeDir;
+
+  // This can fail if $HOME is not set and getpwuid fails.
   bool Result = llvm::sys::path::home_directory(HomeDir);
   if (Result) {
     ASSERT_NO_ERROR(fs::real_path(HomeDir, Expected));
@@ -528,6 +530,25 @@
   ASSERT_NO_ERROR(fs::remove_directories(Twine(TestDirectory) + "/test1"));
 }
 
+TEST_F(FileSystemTest, ExpandTilde) {
+  SmallString<64> Expected;
+  SmallString<64> Actual;
+  SmallString<64> HomeDir;
+
+  // This can fail if $HOME is not set and getpwuid fails.
+  bool Result = llvm::sys::path::home_directory(HomeDir);
+  if (Result) {
+    fs::expand_tilde(HomeDir, Expected);
+
+    fs::expand_tilde("~", Actual);
+    EXPECT_EQ(Expected, Actual);
+
+    path::append(Expected, "foo");
+    fs::expand_tilde("~/foo", Actual);
+    EXPECT_EQ(Expected, Actual);
+  }
+}
+
 #ifdef LLVM_ON_UNIX
 TEST_F(FileSystemTest, RealPathNoReadPerm) {
   SmallString<64> Expanded;