Revert "Support: Add mapped_file_region::sync(), equivalent to msync"

This reverts commit 142f51fc2f.

This shouldn't be committed, it got committed accidentally.

llvm/include/llvm/Support/FileSystem.h

@@ -1337,9 +1337,6 @@ public:
   /// behavior.
   const char *const_data() const;
 
-  /// Write changes to disk and synchronize. Equivalent to POSIX msync.
-  std::error_code sync() const;
-
   /// \returns The minimum alignment offset must be.
   static int alignment();
 };

llvm/lib/Support/Unix/Path.inc

@@ -885,14 +885,6 @@ void mapped_file_region::dontNeedImpl() {
 #endif
 }
 
-std::error_code mapped_file_region::sync() const {
-  assert(Mapping && "Mapping failed but used anyway!");
-  assert(Mode == readwrite && "sync only valid for readwrite regions!");
-  if (::msync(Mapping, Size, MS_SYNC))
-    return std::error_code(errno, std::generic_category());
-  return std::error_code();
-}
-
 int mapped_file_region::alignment() {
   return Process::getPageSizeEstimate();
 }

llvm/lib/Support/Windows/Path.inc

@@ -963,16 +963,6 @@ void mapped_file_region::unmapImpl() {
 
 void mapped_file_region::dontNeedImpl() {}
 
-std::error_code mapped_file_region::sync() const {
-  assert(Mapping && "Mapping failed but used anyway!");
-  assert(Mode == readwrite && "sync only valid for readwrite regions!");
-  if (!::FlushViewOfFile(Mapping, Size))
-    return mapWindowsError(GetLastError());
-  if (!::FlushFileBuffers(FileHandle))
-    return mapWindowsError(GetLastError());
-  return std::error_code();
-}
-
 int mapped_file_region::alignment() {
   SYSTEM_INFO SysInfo;
   ::GetSystemInfo(&SysInfo);

llvm/unittests/Support/Path.cpp

@@ -1463,33 +1463,6 @@ TEST_F(FileSystemTest, FileMapping) {
   ASSERT_NO_ERROR(fs::remove(TempPath));
 }
 
-TEST_F(FileSystemTest, FileMappingSync) {
-  // Create a temp file.
-  int FD;
-  SmallString<64> TempPath;
-  ASSERT_NO_ERROR(fs::createTemporaryFile("prefix", "temp", FD, TempPath));
-  StringRef Content("hello there");
-  ASSERT_NO_ERROR(fs::resize_file_before_mapping_readwrite(FD, Content.size()));
-
-  {
-    // Map in the file and write some content.
-    std::error_code EC;
-    fs::mapped_file_region mfr(fs::convertFDToNativeFile(FD),
-                               fs::mapped_file_region::readwrite,
-                               Content.size(), 0, EC);
-    ASSERT_NO_ERROR(EC);
-    ASSERT_EQ(close(FD), 0);
-    std::copy(Content.begin(), Content.end(), mfr.data());
-
-    // Synchronize and check the contents before unmapping.
-    mfr.sync();
-    auto Buffer = MemoryBuffer::getFile(TempPath);
-    ASSERT_TRUE((bool)Buffer);
-    ASSERT_EQ(Content, Buffer->get()->getBuffer());
-  }
-  ASSERT_NO_ERROR(fs::remove(TempPath));
-}
-
 TEST(Support, NormalizePath) {
   //                           Input,        Expected Win, Expected Posix
   using TestTuple = std::tuple<const char *, const char *, const char *>;