[Support] NFC: Allow modifying access/modification times independently in sys::fs::setLastModificationAndAccessTime.

Summary:
Add an overload to sys::fs::setLastModificationAndAccessTime that allows setting last access and modification times separately. This will allow tools to use this API when they want to preserve both the access and modification times from an input file, which may be different.

Also note that both the POSIX (futimens/futimes) and Windows (SetFileTime) APIs take the two timestamps in the order of (1) access (2) modification time, so this renames the method to "setLastAccessAndModificationTime" to make it clear which timestamp is which.

For existing callers, the 1-arg overload just sets both timestamps to the same thing.

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D50521

llvm-svn: 339628
diff --git a/llvm/include/llvm/Support/FileSystem.h b/llvm/include/llvm/Support/FileSystem.h
index 02db459..66bd18a 100644
--- a/llvm/include/llvm/Support/FileSystem.h
+++ b/llvm/include/llvm/Support/FileSystem.h
@@ -666,7 +666,15 @@
 /// @returns errc::success if the file times were successfully set, otherwise a
 ///          platform-specific error_code or errc::function_not_supported on
 ///          platforms where the functionality isn't available.
-std::error_code setLastModificationAndAccessTime(int FD, TimePoint<> Time);
+std::error_code setLastAccessAndModificationTime(int FD, TimePoint<> AccessTime,
+                                                 TimePoint<> ModificationTime);
+
+/// Simpler version that sets both file modification and access time to the same
+/// time.
+inline std::error_code setLastAccessAndModificationTime(int FD,
+                                                        TimePoint<> Time) {
+  return setLastAccessAndModificationTime(FD, Time, Time);
+}
 
 /// Is status available?
 ///
diff --git a/llvm/lib/Support/Unix/Path.inc b/llvm/lib/Support/Unix/Path.inc
index 7ad57d8..3ca006a 100644
--- a/llvm/lib/Support/Unix/Path.inc
+++ b/llvm/lib/Support/Unix/Path.inc
@@ -583,17 +583,22 @@
   return std::error_code();
 }
 
-std::error_code setLastModificationAndAccessTime(int FD, TimePoint<> Time) {
+std::error_code setLastAccessAndModificationTime(int FD, TimePoint<> AccessTime,
+                                                 TimePoint<> ModificationTime) {
 #if defined(HAVE_FUTIMENS)
   timespec Times[2];
-  Times[0] = Times[1] = sys::toTimeSpec(Time);
+  Times[0] = sys::toTimeSpec(AccessTime);
+  Times[1] = sys::toTimeSpec(ModificationTime);
   if (::futimens(FD, Times))
     return std::error_code(errno, std::generic_category());
   return std::error_code();
 #elif defined(HAVE_FUTIMES)
   timeval Times[2];
-  Times[0] = Times[1] = sys::toTimeVal(
-      std::chrono::time_point_cast<std::chrono::microseconds>(Time));
+  Times[0] = sys::toTimeVal(
+      std::chrono::time_point_cast<std::chrono::microseconds>(AccessTime));
+  Times[1] =
+      sys::toTimeVal(std::chrono::time_point_cast<std::chrono::microseconds>(
+          ModificationTime));
   if (::futimes(FD, Times))
     return std::error_code(errno, std::generic_category());
   return std::error_code();
diff --git a/llvm/lib/Support/Windows/Path.inc b/llvm/lib/Support/Windows/Path.inc
index f425d60..57557db 100644
--- a/llvm/lib/Support/Windows/Path.inc
+++ b/llvm/lib/Support/Windows/Path.inc
@@ -766,10 +766,12 @@
   return std::error_code();
 }
 
-std::error_code setLastModificationAndAccessTime(int FD, TimePoint<> Time) {
-  FILETIME FT = toFILETIME(Time);
+std::error_code setLastAccessAndModificationTime(int FD, TimePoint<> AccessTime,
+                                                 TimePoint<> ModificationTime) {
+  FILETIME AccessFT = toFILETIME(AccessTime);
+  FILETIME ModifyFT = toFILETIME(ModificationTime);
   HANDLE FileHandle = reinterpret_cast<HANDLE>(_get_osfhandle(FD));
-  if (!SetFileTime(FileHandle, NULL, &FT, &FT))
+  if (!SetFileTime(FileHandle, NULL, &AccessFT, &ModifyFT))
     return mapWindowsError(::GetLastError());
   return std::error_code();
 }
diff --git a/llvm/tools/llvm-ar/llvm-ar.cpp b/llvm/tools/llvm-ar/llvm-ar.cpp
index 64be08f..16fee89d 100644
--- a/llvm/tools/llvm-ar/llvm-ar.cpp
+++ b/llvm/tools/llvm-ar/llvm-ar.cpp
@@ -410,7 +410,7 @@
     auto ModTimeOrErr = C.getLastModified();
     failIfError(ModTimeOrErr.takeError());
     failIfError(
-        sys::fs::setLastModificationAndAccessTime(FD, ModTimeOrErr.get()));
+        sys::fs::setLastAccessAndModificationTime(FD, ModTimeOrErr.get()));
   }
 
   if (close(FD))
diff --git a/llvm/unittests/Support/Path.cpp b/llvm/unittests/Support/Path.cpp
index 158d6cf..0207672 100644
--- a/llvm/unittests/Support/Path.cpp
+++ b/llvm/unittests/Support/Path.cpp
@@ -1297,7 +1297,7 @@
   ASSERT_NO_ERROR(sys::fs::openFileForWrite(Twine(TempPath), FileDescriptor,
                                             fs::CD_OpenExisting));
   TimePoint<> Epoch(std::chrono::milliseconds(0));
-  ASSERT_NO_ERROR(fs::setLastModificationAndAccessTime(FileDescriptor, Epoch));
+  ASSERT_NO_ERROR(fs::setLastAccessAndModificationTime(FileDescriptor, Epoch));
   ::close(FileDescriptor);
 
   // Open the file and ensure access time is updated, when forced.