Reapply "Add Chrono.h - std::chrono support header"

This is a resubmission of r284590. The mingw build should be fixed now. The
problem was we were matching time_t with _localtime_64s, which was incorrect on
_USE_32BIT_TIME_T systems. Instead I use localtime_s, which should always
evaluate to the correct function.

llvm-svn: 284720

1 files changed, 10 insertions, 0 deletions

diff --git a/llvm/unittests/Support/TimeValueTest.cpp b/llvm/unittests/Support/TimeValueTest.cpp
index 3d2b9780c06..9e8690f57bc 100644
--- a/llvm/unittests/Support/TimeValueTest.cpp
+++ b/llvm/unittests/Support/TimeValueTest.cpp
@@ -37,4 +37,14 @@ TEST(TimeValue, Win32FILETIME) {
   EXPECT_EQ(ft1970, epoch.toWin32Time());
 }
 
+TEST(TimeValue, Chrono) {
+  sys::TimeValue TV;
+  TV.fromEpochTime(0);
+  sys::TimePoint<> TP = TV;
+  EXPECT_EQ(0u, sys::toTimeT(TP));
+
+  TP += std::chrono::seconds(47);
+  TV = TP;
+  EXPECT_EQ(47u, TV.toEpochTime());
+}
 }