Index: include/llvm/Support/FileSystem.h
===================================================================
--- include/llvm/Support/FileSystem.h
+++ include/llvm/Support/FileSystem.h
@@ -554,7 +554,7 @@
 /// This is an atomic operation. Either the file is created and opened, or the
 /// file system is left untouched.
 ///
-/// The intendend use is for files that are to be kept, possibly after
+/// The intended use is for files that are to be kept, possibly after
 /// renaming them. For example, when running 'clang -c foo.o', the file can
 /// be first created as foo-abc123.o and then renamed.
 ///
Index: lib/Object/ArchiveWriter.cpp
===================================================================
--- lib/Object/ArchiveWriter.cpp
+++ lib/Object/ArchiveWriter.cpp
@@ -305,9 +305,13 @@
                    std::vector<NewArchiveIterator> &NewMembers,
                    bool WriteSymtab, object::Archive::Kind Kind,
                    bool Deterministic, bool Thin) {
+  SmallString<128> AbsolutePath(ArcName);
+  if (auto EC = sys::fs::make_absolute(AbsolutePath))
+    return std::make_pair(ArcName, EC);
+
   SmallString<128> TmpArchive;
   int TmpArchiveFD;
-  if (auto EC = sys::fs::createUniqueFile(ArcName + ".temp-archive-%%%%%%%.a",
+  if (auto EC = sys::fs::createUniqueFile(AbsolutePath + ".temp-archive-%%%%%%%.a",
                                           TmpArchiveFD, TmpArchive))
     return std::make_pair(ArcName, EC);
 
Index: lib/Support/FileOutputBuffer.cpp
===================================================================
--- lib/Support/FileOutputBuffer.cpp
+++ lib/Support/FileOutputBuffer.cpp
@@ -16,6 +16,7 @@
 #include "llvm/ADT/SmallString.h"
 #include "llvm/Support/Errc.h"
 #include "llvm/Support/Signals.h"
+#include "llvm/Support/Path.h"
 #include <system_error>
 
 #if !defined(_MSC_VER) && !defined(__MINGW32__)
@@ -68,9 +69,15 @@
     Mode |= sys::fs::all_exe;
 
   // Create new file in same directory but with random name.
-  SmallString<128> TempFilePath;
+  SmallString<128> TempFilePath, AbsolutePath(FilePath);
   int FD;
-  EC = sys::fs::createUniqueFile(Twine(FilePath) + ".tmp%%%%%%%", FD,
+
+  AbsolutePath += ".tmp%%%%%%%";
+
+  EC = sys::fs::make_absolute(AbsolutePath);
+  if (EC)
+    return EC;
+  EC = sys::fs::createUniqueFile(Twine(AbsolutePath), FD,
                                  TempFilePath, Mode);
   if (EC)
     return EC;
Index: lib/Support/Path.cpp
===================================================================
--- lib/Support/Path.cpp
+++ lib/Support/Path.cpp
@@ -687,13 +687,13 @@
 std::error_code createUniqueFile(const Twine &Model, int &ResultFd,
                                  SmallVectorImpl<char> &ResultPath,
                                  unsigned Mode) {
-  return createUniqueEntity(Model, ResultFd, ResultPath, false, Mode, FS_File);
+  return createUniqueEntity(Model, ResultFd, ResultPath, true, Mode, FS_File);
 }
 
 std::error_code createUniqueFile(const Twine &Model,
                                  SmallVectorImpl<char> &ResultPath) {
   int Dummy;
-  return createUniqueEntity(Model, Dummy, ResultPath, false, 0, FS_Name);
+  return createUniqueEntity(Model, Dummy, ResultPath, true, 0, FS_Name);
 }
 
 static std::error_code
Index: unittests/Support/Path.cpp
===================================================================
--- unittests/Support/Path.cpp
+++ unittests/Support/Path.cpp
@@ -432,6 +432,7 @@
   SmallString<64> TempPath2;
   ASSERT_NO_ERROR(fs::createTemporaryFile("prefix", "temp", FD2, TempPath2));
   ASSERT_TRUE(TempPath2.endswith(".temp"));
+  ASSERT_TRUE(!TempPath2.endswith("..temp"));
   ASSERT_NE(TempPath.str(), TempPath2.str());
 
   fs::file_status A, B;
@@ -498,6 +499,22 @@
   ASSERT_NO_ERROR(fs::createTemporaryFile(Path216, "", TempPath));
   ASSERT_NO_ERROR(fs::remove(Twine(TempPath)));
 #endif
+
+  SmallString<64> AbsolutePath;
+  sys::path::system_temp_directory(true, AbsolutePath);
+  SmallString<64> UniquePath;
+
+  // Pass an absolute model to createUniqueFile.  The resulting
+  // path should still be absolute.
+  path::append(AbsolutePath, "unique%%%%%%.txt");
+  ASSERT_NO_ERROR(fs::createUniqueFile(Twine(AbsolutePath), UniquePath));
+  EXPECT_TRUE(path::is_absolute(UniquePath));
+
+  // Pass a relative model to createUniqueFile.  The resulting
+  // path should be absolute.
+  Twine relativePath = Twine("unique%%%%%%.txt");
+  ASSERT_NO_ERROR(fs::createUniqueFile(relativePath, UniquePath));
+  EXPECT_TRUE(path::is_absolute(UniquePath));
 }
 
 TEST_F(FileSystemTest, CreateDir) {