[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, 7 insertions, 2 deletions

diff --git a/lldb/source/Plugins/Process/scripted/ScriptedProcess.cpp b/lldb/source/Plugins/Process/scripted/ScriptedProcess.cpp
index d2111ce..304c121 100644
--- a/lldb/source/Plugins/Process/scripted/ScriptedProcess.cpp
+++ b/lldb/source/Plugins/Process/scripted/ScriptedProcess.cpp
@@ -182,10 +182,15 @@ void ScriptedProcess::DidResume() {
   m_pid = GetInterface().GetProcessID();
 }
 
-Status ScriptedProcess::DoResume() {
+Status ScriptedProcess::DoResume(RunDirection direction) {
   LLDB_LOGF(GetLog(LLDBLog::Process), "ScriptedProcess::%s resuming process", __FUNCTION__);
 
-  return GetInterface().Resume();
+  if (direction == RunDirection::eRunForward) {
+    return GetInterface().Resume();
+  } else {
+    return Status::FromErrorStringWithFormatv(
+        "error: {0} does not support reverse execution of processes", GetPluginName());
+  }
 }
 
 Status ScriptedProcess::DoAttach(const ProcessAttachInfo &attach_info) {