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

Reverting this again; I added a commit which added @skipIfDarwin
markers to the TestReverseContinueBreakpoints.py and
TestReverseContinueNotSupported.py API tests, which use lldb-server
in gdbserver mode which does not work on Darwin.  But the aarch64 ubuntu
bot reported a failure on TestReverseContinueBreakpoints.py,
https://lab.llvm.org/buildbot/#/builders/59/builds/6397

  File "/home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/llvm-project/lldb/test/API/functionalities/reverse-execution/TestReverseContinueBreakpoints.py", line 63, in test_reverse_continue_skip_breakpoint
    self.reverse_continue_skip_breakpoint_internal(async_mode=False)
  File "/home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/llvm-project/lldb/test/API/functionalities/reverse-execution/TestReverseContinueBreakpoints.py", line 81, in reverse_continue_skip_breakpoint_internal
    self.expect(
  File "/home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/llvm-project/lldb/packages/Python/lldbsuite/test/lldbtest.py", line 2372, in expect
    self.runCmd(
  File "/home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/llvm-project/lldb/packages/Python/lldbsuite/test/lldbtest.py", line 1002, in runCmd
    self.assertTrue(self.res.Succeeded(), msg + output)
AssertionError: False is not true : Process should be stopped due to history boundary
Error output:
error: Process must be launched.

This reverts commit 4f29756.

Author: jasonmolenda

lldb/include/lldb/API/SBProcess.h

@@ -159,7 +159,6 @@ class LLDB_API SBProcess {
   lldb::SBError Destroy();
 
   lldb::SBError Continue();
-  lldb::SBError Continue(RunDirection direction);
 
   lldb::SBError Stop();
 

lldb/include/lldb/Target/Process.h

@@ -857,10 +857,10 @@ class Process : public std::enable_shared_from_this<Process>,
   /// \see Thread:Resume()
   /// \see Thread:Step()
   /// \see Thread:Suspend()
-  Status Resume(lldb::RunDirection direction = lldb::eRunForward);
+  Status Resume();
 
   /// Resume a process, and wait for it to stop.
-  Status ResumeSynchronous(Stream *stream, lldb::RunDirection direction = lldb::eRunForward);
+  Status ResumeSynchronous(Stream *stream);
 
   /// Halts a running process.
   ///
@@ -1104,14 +1104,9 @@ class Process : public std::enable_shared_from_this<Process>,
   /// \see Thread:Resume()
   /// \see Thread:Step()
   /// \see Thread:Suspend()
-  virtual Status DoResume(lldb::RunDirection direction) {
-    if (direction == lldb::RunDirection::eRunForward) {
-      return Status::FromErrorStringWithFormatv(
-          "error: {0} does not support resuming processes", GetPluginName());
-    } else {
-      return Status::FromErrorStringWithFormatv(
-          "error: {0} does not support reverse execution of processes", GetPluginName());
-    }
+  virtual Status DoResume() {
+    return Status::FromErrorStringWithFormatv(
+        "error: {0} does not support resuming processes", GetPluginName());
   }
 
   /// Called after resuming a process.
@@ -2337,8 +2332,6 @@ class Process : public std::enable_shared_from_this<Process>,
 
   bool IsRunning() const;
 
-  lldb::RunDirection GetLastRunDirection() { return m_last_run_direction; }
-
   DynamicCheckerFunctions *GetDynamicCheckers() {
     return m_dynamic_checkers_up.get();
   }
@@ -2858,7 +2851,7 @@ void PruneThreadPlans();
   ///
   /// \return
   ///     An Status object describing the success or failure of the resume.
-  Status PrivateResume(lldb::RunDirection direction = lldb::eRunForward);
+  Status PrivateResume();
 
   // Called internally
   void CompleteAttach();
@@ -3134,8 +3127,6 @@ void PruneThreadPlans();
                            // m_currently_handling_do_on_removals are true,
                            // Resume will only request a resume, using this
                            // flag to check.
-  // The direction of execution from the last time this process was resumed.
-  lldb::RunDirection m_last_run_direction;
 
   lldb::tid_t m_interrupt_tid; /// The tid of the thread that issued the async
                                /// interrupt, used by thread plan timeout. It

lldb/include/lldb/Target/StopInfo.h

@@ -142,12 +142,6 @@ class StopInfo : public std::enable_shared_from_this<StopInfo> {
   static lldb::StopInfoSP
   CreateStopReasonProcessorTrace(Thread &thread, const char *description);
 
-  // This creates a StopInfo indicating that execution stopped because
-  // it was replaying some recorded execution history, and execution reached
-  // the end of that recorded history.
-  static lldb::StopInfoSP
-  CreateStopReasonHistoryBoundary(Thread &thread, const char *description);
-
   static lldb::StopInfoSP CreateStopReasonFork(Thread &thread,
                                                lldb::pid_t child_pid,
                                                lldb::tid_t child_tid);

lldb/include/lldb/lldb-enumerations.h

@@ -135,9 +135,6 @@ FLAGS_ENUM(LaunchFlags){
 /// Thread Run Modes.
 enum RunMode { eOnlyThisThread, eAllThreads, eOnlyDuringStepping };
 
-/// Execution directions
-enum RunDirection { eRunForward, eRunReverse };
-
 /// Byte ordering definitions.
 enum ByteOrder {
   eByteOrderInvalid = 0,
@@ -257,9 +254,6 @@ enum StopReason {
   eStopReasonVFork,
   eStopReasonVForkDone,
   eStopReasonInterrupt, ///< Thread requested interrupt
-  // Indicates that execution stopped because the debugger backend relies
-  // on recorded data and we reached the end of that data.
-  eStopReasonHistoryBoundary,
 };
 
 /// Command Return Status Types.

lldb/packages/Python/lldbsuite/test/gdbclientutils.py

@@ -510,9 +510,8 @@ def start(self):
         self._thread.start()
 
     def stop(self):
-        if self._thread is not None:
-            self._thread.join()
-            self._thread = None
+        self._thread.join()
+        self._thread = None
 
     def get_connect_address(self):
         return self._socket.get_connect_address()