Fix TimeValue::now() on Unix.

TimeValue()::now().toEpochTime() is supposed to be the same as time(),
but it wasn't, because toEpoch subtracted PosixZeroTime, but now()
didn't add PosixZeroTime!
Add a unittest to check this works.

llvm-svn: 94178

llvm/lib/System/Unix/TimeValue.inc

@@ -48,7 +48,7 @@ TimeValue TimeValue::now() {
   }
 
   return TimeValue(
-    static_cast<TimeValue::SecondsType>( the_time.tv_sec ), 
+    static_cast<TimeValue::SecondsType>( the_time.tv_sec + PosixZeroTime.seconds_ ), 
     static_cast<TimeValue::NanoSecondsType>( the_time.tv_usec * 
       NANOSECONDS_PER_MICROSECOND ) );
 }

llvm/unittests/Support/System.cpp

+//===- llvm/unittest/Support/System.cpp - System tests --===//
+#include "gtest/gtest.h"
+#include "llvm/System/TimeValue.h"
+#include <time.h>
+
+using namespace llvm;
+namespace {
+class SystemTest : public ::testing::Test {
+};
+
+TEST_F(SystemTest, TimeValue) {
+  sys::TimeValue now = sys::TimeValue::now();
+  time_t now_t = time(NULL);
+  EXPECT_TRUE(abs(now_t - now.toEpochTime()) < 2);
+}
+}