[FileSystem] Ignore nanoseconds when comparing oso_mod_time

After a recent change in LLVM the TimePoint encoding become more
precise, exceeding the precision of the TimePoint obtained from the
DebugMap. This patch adds a flag to the GetModificationTime helper in
the FileSystem to return the modification time with less precision.

Thanks to Davide for bisecting this failure on the LLDB bots.

llvm-svn: 347615

1 files changed, 11 insertions, 4 deletions

diff --git a/lldb/source/Host/common/FileSystem.cpp b/lldb/source/Host/common/FileSystem.cpp
index a010599..db218a3 100644
--- a/lldb/source/Host/common/FileSystem.cpp
+++ b/lldb/source/Host/common/FileSystem.cpp
@@ -64,15 +64,22 @@ Optional<FileSystem> &FileSystem::InstanceImpl() {
 }
 
 sys::TimePoint<>
-FileSystem::GetModificationTime(const FileSpec &file_spec) const {
-  return GetModificationTime(file_spec.GetPath());
+FileSystem::GetModificationTime(const FileSpec &file_spec,
+                                bool nanosecond_precision) const {
+  return GetModificationTime(file_spec.GetPath(), nanosecond_precision);
 }
 
-sys::TimePoint<> FileSystem::GetModificationTime(const Twine &path) const {
+sys::TimePoint<>
+FileSystem::GetModificationTime(const Twine &path,
+                                bool nanosecond_precision) const {
   ErrorOr<vfs::Status> status = m_fs->status(path);
   if (!status)
     return sys::TimePoint<>();
-  return status->getLastModificationTime();
+  if (nanosecond_precision)
+    return status->getLastModificationTime();
+  else
+    return std::chrono::time_point_cast<std::chrono::seconds>(
+        status->getLastModificationTime());
 }
 
 uint64_t FileSystem::GetByteSize(const FileSpec &file_spec) const {