Remove TimeValue usage from llvm/Support

Summary:
This is a follow-up to D25416. It removes all usages of TimeValue from
llvm/Support library (except for the actual TimeValue declaration), and replaces
them with appropriate usages of std::chrono. To facilitate this, I have added
small utility functions for converting time points and durations into appropriate
OS-specific types (FILETIME, struct timespec, ...).

Reviewers: zturner, mehdi_amini

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D25730

llvm-svn: 284966

llvm/tools/llvm-cov/CodeCoverage.cpp

@@ -30,6 +30,7 @@
 #include "llvm/Support/Path.h"
 #include "llvm/Support/Process.h"
 #include "llvm/Support/Program.h"
+#include "llvm/Support/ScopedPrinter.h"
 #include "llvm/Support/ThreadPool.h"
 #include "llvm/Support/ToolOutputFile.h"
 #include <functional>
@@ -734,7 +735,7 @@ int CodeCoverageTool::show(int argc, const char **argv,
   }
 
   auto ModifiedTime = Status.getLastModificationTime();
-  std::string ModifiedTimeStr = ModifiedTime.str();
+  std::string ModifiedTimeStr = to_string(ModifiedTime);
   size_t found = ModifiedTimeStr.rfind(":");
   ViewOpts.CreatedTimeStr = (found != std::string::npos)
                                 ? "Created: " + ModifiedTimeStr.substr(0, found)