Add Chrono.h - std::chrono support header

Summary:
std::chrono mostly covers the functionality of llvm::sys::TimeValue and
lldb_private::TimeValue. This header adds a bit of utility functions and
typedefs, which make the usage of the library and porting code from TimeValues
easier.

Rationale:
- TimePoint typedef - precision of system_clock is implementation defined -
  using a well-defined precision helps maintain consistency between platforms,
  makes it interact better with existing TimeValue classes, and avoids cases
  there a time point is implicitly convertible to a specific precision on some
  platforms but not on others.
- system_clock::to_time_t only accepts time_points with the default system
  precision (even though time_t has only second precision on all platforms we
  support). To avoid the need for explicit casts, I have added a toTimeT()
  wrapper function. toTimePoint(time_t) was not strictly necessary, but I have
  added it for symmetry.

Reviewers: zturner, mehdi_amini

Subscribers: beanz, mgorny, llvm-commits, modocache

Differential Revision: https://reviews.llvm.org/D25416

llvm-svn: 284590

1 files changed, 0 insertions, 54 deletions

diff --git a/llvm/lib/Support/Unix/TimeValue.inc b/llvm/lib/Support/Unix/TimeValue.inc
deleted file mode 100644
index 042e0dacc34..00000000000
--- a/llvm/lib/Support/Unix/TimeValue.inc
+++ /dev/null
@@ -1,54 +0,0 @@
-//===- Unix/TimeValue.cpp - Unix TimeValue Implementation -------*- C++ -*-===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// This file implements the Unix specific portion of the TimeValue class.
-//
-//===----------------------------------------------------------------------===//
-
-//===----------------------------------------------------------------------===//
-//=== WARNING: Implementation here must contain only generic UNIX code that
-//===          is guaranteed to work on *all* UNIX variants.
-//===----------------------------------------------------------------------===//
-
-#include "Unix.h"
-
-namespace llvm {
-  using namespace sys;
-
-std::string TimeValue::str() const {
-  time_t OurTime = time_t(this->toEpochTime());
-  struct tm Storage;
-  struct tm *LT = ::localtime_r(&OurTime, &Storage);
-  assert(LT);
-  char Buffer1[sizeof("YYYY-MM-DD HH:MM:SS")];
-  strftime(Buffer1, sizeof(Buffer1), "%Y-%m-%d %H:%M:%S", LT);
-  char Buffer2[sizeof("YYYY-MM-DD HH:MM:SS.MMMUUUNNN")];
-  snprintf(Buffer2, sizeof(Buffer2), "%s.%.9u", Buffer1, this->nanoseconds());
-  return std::string(Buffer2);
-}
-
-TimeValue TimeValue::now() {
-  struct timeval the_time;
-  timerclear(&the_time);
-  if (0 != ::gettimeofday(&the_time,nullptr)) {
-    // This is *really* unlikely to occur because the only gettimeofday
-    // errors concern the timezone parameter which we're passing in as 0.
-    // In the unlikely case it does happen, just return MinTime, no error
-    // message needed.
-    return MinTime();
-  }
-
-  return TimeValue(
-    static_cast<TimeValue::SecondsType>( the_time.tv_sec +
-      PosixZeroTimeSeconds ),
-    static_cast<TimeValue::NanoSecondsType>( the_time.tv_usec *
-      NANOSECONDS_PER_MICROSECOND ) );
-}
-
-}