I noticed that LLDB takes longer to stop than it should. Running a tiny
program like `int main() { return 0; }` in LLDB with `lldb test.exe -o r
-o q` takes about five seconds.
This is caused by the `WaitForMultipleObjects` in
[`ConnectionGenericFile::Read`](25976e8360/lldb/source/Host/windows/ConnectionGenericFileWindows.cpp (L191-L192))
timing out (it has a timeout of 5s).
It times out, because we never close the PTY created in
[`ProcessLaunchInfo::SetUpPtyRedirection`](25976e8360/lldb/source/Host/common/ProcessLaunchInfo.cpp (L213)).
When we call `target->GetProcessLaunchInfo().GetPTY().Close()` in
`ProcessWindows::OnExitProcess`, we don't access the PTY we created when
setting up the redirection - we're closing a default constructed one.
This is because the target's `m_launch_info` isn't necessarily the
`launch_info` we get in
[`Target::FinalizeFileActions`](4a8a0593bd/lldb/source/Target/Target.cpp (L3850))
when calling `SetUpPtyRedirection`.
With this PR, we store the PTY that a process was launched with inside
`ProcessWindows`, so we can later close it.
The wait of five seconds and a timed out `WaitForMultipleObjects` sounds
similar to https://github.com/llvm/llvm-project/pull/159308, but it's a
different call to `WaitForMultipleObjects` here. Still, I wonder if we
could do something to detect this earlier. Maybe some warning message or
debug-only assert if these waits time out?
783fbdc54e