1 files changed, 19 insertions, 4 deletions
diff --git a/lldb/source/Host/posix/MainLoopPosix.cpp b/lldb/source/Host/posix/MainLoopPosix.cpp
index aecdeb9..ce7caa3 100644
--- a/lldb/source/Host/posix/MainLoopPosix.cpp
+++ b/lldb/source/Host/posix/MainLoopPosix.cpp
@@ -99,6 +99,7 @@ public:
   ~RunImpl() = default;
 
   Status Poll();
+
   void ProcessReadEvents();
 
 private:
@@ -159,6 +160,22 @@ MainLoopPosix::RunImpl::RunImpl(MainLoopPosix &loop) : loop(loop) {
   read_fds.reserve(loop.m_read_fds.size());
 }
 
+static int StartPoll(llvm::MutableArrayRef<struct pollfd> fds,
+                     std::optional<MainLoopPosix::TimePoint> point) {
+#if HAVE_PPOLL
+  return ppoll(fds.data(), fds.size(), ToTimeSpec(point),
+               /*sigmask=*/nullptr);
+#else
+  using namespace std::chrono;
+  int timeout = -1;
+  if (point) {
+    nanoseconds dur = std::max(*point - steady_clock::now(), nanoseconds(0));
+    timeout = ceil<milliseconds>(dur).count();
+  }
+  return poll(fds.data(), fds.size(), timeout);
+#endif
+}
+
 Status MainLoopPosix::RunImpl::Poll() {
   read_fds.clear();
 
@@ -169,11 +186,9 @@ Status MainLoopPosix::RunImpl::Poll() {
     pfd.revents = 0;
     read_fds.push_back(pfd);
   }
+  int ready = StartPoll(read_fds, loop.GetNextWakeupTime());
 
-  if (ppoll(read_fds.data(), read_fds.size(),
-            ToTimeSpec(loop.GetNextWakeupTime()),
-            /*sigmask=*/nullptr) == -1 &&
-      errno != EINTR)
+  if (ready == -1 && errno != EINTR)
     return Status(errno, eErrorTypePOSIX);
 
   return Status();