[lldb] Implement basic support for reverse-continue (#99736)

This commit only adds support for the
`SBProcess::ReverseContinue()` API. A user-accessible command for this
will follow in a later commit.

This feature depends on a gdbserver implementation (e.g. `rr`) providing
support for the `bc` and `bs` packets. `lldb-server` does not support
those packets, and there is no plan to change that. So, for testing
purposes, `lldbreverse.py` wraps `lldb-server` with a Python
implementation of *very limited* record-and-replay functionality for use
by *tests only*.

The majority of this PR is test infrastructure (about 700 of the 950
lines added).

1 files changed, 8 insertions, 1 deletions

diff --git a/lldb/source/Plugins/Process/MacOSX-Kernel/ProcessKDP.cpp b/lldb/source/Plugins/Process/MacOSX-Kernel/ProcessKDP.cpp
index 9b2907c..116c43343 100644
--- a/lldb/source/Plugins/Process/MacOSX-Kernel/ProcessKDP.cpp
+++ b/lldb/source/Plugins/Process/MacOSX-Kernel/ProcessKDP.cpp
@@ -402,9 +402,16 @@ lldb_private::DynamicLoader *ProcessKDP::GetDynamicLoader() {
 
 Status ProcessKDP::WillResume() { return Status(); }
 
-Status ProcessKDP::DoResume() {
+Status ProcessKDP::DoResume(RunDirection direction) {
   Status error;
   Log *log = GetLog(KDPLog::Process);
+
+  if (direction == RunDirection::eRunReverse) {
+    error.SetErrorStringWithFormatv(
+        "error: {0} does not support reverse execution of processes", GetPluginName());
+    return error;
+  }
+
   // Only start the async thread if we try to do any process control
   if (!m_async_thread.IsJoinable())
     StartAsyncThread();