[Lldb-commits] [lldb] 2ff4c25 - Revert "[lldb] Implement basic support for reverse-continue (#99736)"

Augusto Noronha via lldb-commits lldb-commits at lists.llvm.org
Thu Oct 10 15:10:55 PDT 2024


Author: Augusto Noronha
Date: 2024-10-10T15:05:58-07:00
New Revision: 2ff4c25b7efff64b3b662d0bedcfe7edebcf20b9

URL: https://github.com/llvm/llvm-project/commit/2ff4c25b7efff64b3b662d0bedcfe7edebcf20b9
DIFF: https://github.com/llvm/llvm-project/commit/2ff4c25b7efff64b3b662d0bedcfe7edebcf20b9.diff

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

This reverts commit d5e1de6da96c1ab3b8cae68447e8ed3696a7006e.

Added: 
    

Modified: 
    lldb/include/lldb/API/SBProcess.h
    lldb/include/lldb/Target/Process.h
    lldb/include/lldb/Target/StopInfo.h
    lldb/include/lldb/lldb-enumerations.h
    lldb/packages/Python/lldbsuite/test/gdbclientutils.py
    lldb/packages/Python/lldbsuite/test/lldbtest.py
    lldb/source/API/SBProcess.cpp
    lldb/source/API/SBThread.cpp
    lldb/source/Interpreter/CommandInterpreter.cpp
    lldb/source/Plugins/Process/Linux/NativeThreadLinux.cpp
    lldb/source/Plugins/Process/MacOSX-Kernel/ProcessKDP.cpp
    lldb/source/Plugins/Process/MacOSX-Kernel/ProcessKDP.h
    lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp
    lldb/source/Plugins/Process/Windows/Common/ProcessWindows.h
    lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
    lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h
    lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp
    lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
    lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.h
    lldb/source/Plugins/Process/scripted/ScriptedProcess.cpp
    lldb/source/Plugins/Process/scripted/ScriptedProcess.h
    lldb/source/Target/Process.cpp
    lldb/source/Target/StopInfo.cpp
    lldb/source/Target/Thread.cpp
    lldb/tools/lldb-dap/JSONUtils.cpp
    lldb/tools/lldb-dap/LLDBUtils.cpp

Removed: 
    lldb/packages/Python/lldbsuite/test/lldbgdbproxy.py
    lldb/packages/Python/lldbsuite/test/lldbreverse.py
    lldb/test/API/functionalities/reverse-execution/Makefile
    lldb/test/API/functionalities/reverse-execution/TestReverseContinueBreakpoints.py
    lldb/test/API/functionalities/reverse-execution/TestReverseContinueNotSupported.py
    lldb/test/API/functionalities/reverse-execution/main.c


################################################################################
diff  --git a/lldb/include/lldb/API/SBProcess.h b/lldb/include/lldb/API/SBProcess.h
index 8b8ed830b54cc0..1624e02070b1b2 100644
--- a/lldb/include/lldb/API/SBProcess.h
+++ b/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();
 

diff  --git a/lldb/include/lldb/Target/Process.h b/lldb/include/lldb/Target/Process.h
index fe7fbc50fd5770..b8c53a474ba6b9 100644
--- a/lldb/include/lldb/Target/Process.h
+++ b/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

diff  --git a/lldb/include/lldb/Target/StopInfo.h b/lldb/include/lldb/Target/StopInfo.h
index 072f71f6b1122f..fae90364deaf0a 100644
--- a/lldb/include/lldb/Target/StopInfo.h
+++ b/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);

diff  --git a/lldb/include/lldb/lldb-enumerations.h b/lldb/include/lldb/lldb-enumerations.h
index 232d1dfdb5c9d0..938f6e3abe8f2a 100644
--- a/lldb/include/lldb/lldb-enumerations.h
+++ b/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.

diff  --git a/lldb/packages/Python/lldbsuite/test/gdbclientutils.py b/lldb/packages/Python/lldbsuite/test/gdbclientutils.py
index 732d6171320680..1784487323ad6b 100644
--- a/lldb/packages/Python/lldbsuite/test/gdbclientutils.py
+++ b/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()

diff  --git a/lldb/packages/Python/lldbsuite/test/lldbgdbproxy.py b/lldb/packages/Python/lldbsuite/test/lldbgdbproxy.py
deleted file mode 100644
index 2a9592bf4545a4..00000000000000
--- a/lldb/packages/Python/lldbsuite/test/lldbgdbproxy.py
+++ /dev/null
@@ -1,175 +0,0 @@
-import logging
-import os
-import os.path
-import random
-
-import lldb
-from lldbsuite.test.lldbtest import *
-from lldbsuite.test.gdbclientutils import *
-import lldbgdbserverutils
-from lldbsuite.support import seven
-
-
-class GDBProxyTestBase(TestBase):
-    """
-    Base class for gdbserver proxy tests.
-
-    This class will setup and start a mock GDB server for the test to use.
-    It pases through requests to a regular lldb-server/debugserver and
-    forwards replies back to the LLDB under test.
-    """
-
-    """The gdbserver that we implement."""
-    server = None
-    """The inner lldb-server/debugserver process that we proxy requests into."""
-    monitor_server = None
-    monitor_sock = None
-
-    server_socket_class = TCPServerSocket
-
-    DEFAULT_TIMEOUT = 20 * (10 if ("ASAN_OPTIONS" in os.environ) else 1)
-
-    _verbose_log_handler = None
-    _log_formatter = logging.Formatter(fmt="%(asctime)-15s %(levelname)-8s %(message)s")
-
-    def setUpBaseLogging(self):
-        self.logger = logging.getLogger(__name__)
-
-        if len(self.logger.handlers) > 0:
-            return  # We have set up this handler already
-
-        self.logger.propagate = False
-        self.logger.setLevel(logging.DEBUG)
-
-        # log all warnings to stderr
-        handler = logging.StreamHandler()
-        handler.setLevel(logging.WARNING)
-        handler.setFormatter(self._log_formatter)
-        self.logger.addHandler(handler)
-
-    def setUp(self):
-        TestBase.setUp(self)
-
-        self.setUpBaseLogging()
-
-        if self.isVerboseLoggingRequested():
-            # If requested, full logs go to a log file
-            log_file_name = self.getLogBasenameForCurrentTest() + "-proxy.log"
-            self._verbose_log_handler = logging.FileHandler(
-               log_file_name
-            )
-            self._verbose_log_handler.setFormatter(self._log_formatter)
-            self._verbose_log_handler.setLevel(logging.DEBUG)
-            self.logger.addHandler(self._verbose_log_handler)
-
-        lldb_server_exe = lldbgdbserverutils.get_lldb_server_exe()
-        if lldb_server_exe is None:
-            self.debug_monitor_exe = lldbgdbserverutils.get_debugserver_exe()
-            self.assertTrue(self.debug_monitor_exe is not None)
-            self.debug_monitor_extra_args = []
-        else:
-            self.debug_monitor_exe = lldb_server_exe
-            self.debug_monitor_extra_args = ["gdbserver"]
-
-        self.server = MockGDBServer(self.server_socket_class())
-        self.server.responder = self
-
-    def tearDown(self):
-        # TestBase.tearDown will kill the process, but we need to kill it early
-        # so its client connection closes and we can stop the server before
-        # finally calling the base tearDown.
-        if self.process() is not None:
-            self.process().Kill()
-        self.server.stop()
-
-        self.logger.removeHandler(self._verbose_log_handler)
-        self._verbose_log_handler = None
-
-        TestBase.tearDown(self)
-
-    def isVerboseLoggingRequested(self):
-        # We will report our detailed logs if the user requested that the "gdb-remote" channel is
-        # logged.
-        return any(("gdb-remote" in channel) for channel in lldbtest_config.channels)
-
-    def connect(self, target):
-        """
-        Create a process by connecting to the mock GDB server.
-        """
-        self.prep_debug_monitor_and_inferior()
-        self.server.start()
-
-        listener = self.dbg.GetListener()
-        error = lldb.SBError()
-        process = target.ConnectRemote(
-            listener, self.server.get_connect_url(), "gdb-remote", error
-        )
-        self.assertTrue(error.Success(), error.description)
-        self.assertTrue(process, PROCESS_IS_VALID)
-        return process
-
-    def get_next_port(self):
-        return 12000 + random.randint(0, 3999)
-
-    def prep_debug_monitor_and_inferior(self):
-        inferior_exe_path = self.getBuildArtifact("a.out")
-        self.connect_to_debug_monitor([inferior_exe_path])
-        self.assertIsNotNone(self.monitor_server)
-        self.initial_handshake()
-
-    def initial_handshake(self):
-        self.monitor_server.send_packet(seven.bitcast_to_bytes("+"))
-        reply = seven.bitcast_to_string(self.monitor_server.get_normal_packet())
-        self.assertEqual(reply, "+")
-        self.monitor_server.send_packet(seven.bitcast_to_bytes("QStartNoAckMode"))
-        reply = seven.bitcast_to_string(self.monitor_server.get_normal_packet())
-        self.assertEqual(reply, "+")
-        reply = seven.bitcast_to_string(self.monitor_server.get_normal_packet())
-        self.assertEqual(reply, "OK")
-        self.monitor_server.send_packet(seven.bitcast_to_bytes("+"))
-        reply = seven.bitcast_to_string(self.monitor_server.get_normal_packet())
-        self.assertEqual(reply, "+")
-
-    def get_debug_monitor_command_line_args(self, connect_address, launch_args):
-        return self.debug_monitor_extra_args + ["--reverse-connect", connect_address] + launch_args
-
-    def launch_debug_monitor(self, launch_args):
-        family, type, proto, _, addr = socket.getaddrinfo(
-            "localhost", 0, proto=socket.IPPROTO_TCP
-        )[0]
-        sock = socket.socket(family, type, proto)
-        sock.settimeout(self.DEFAULT_TIMEOUT)
-        sock.bind(addr)
-        sock.listen(1)
-        addr = sock.getsockname()
-        connect_address = "[{}]:{}".format(*addr)
-
-        commandline_args = self.get_debug_monitor_command_line_args(
-            connect_address, launch_args
-        )
-
-        # Start the server.
-        self.logger.info(f"Spawning monitor {commandline_args}")
-        monitor_process = self.spawnSubprocess(
-            self.debug_monitor_exe, commandline_args, install_remote=False
-        )
-        self.assertIsNotNone(monitor_process)
-
-        self.monitor_sock = sock.accept()[0]
-        self.monitor_sock.settimeout(self.DEFAULT_TIMEOUT)
-        return monitor_process
-
-    def connect_to_debug_monitor(self, launch_args):
-        monitor_process = self.launch_debug_monitor(launch_args)
-        self.monitor_server = lldbgdbserverutils.Server(self.monitor_sock, monitor_process)
-
-    def respond(self, packet):
-        """Subclasses can override this to change how packets are handled."""
-        return self.pass_through(packet)
-
-    def pass_through(self, packet):
-        self.logger.info(f"Sending packet {packet}")
-        self.monitor_server.send_packet(seven.bitcast_to_bytes(packet))
-        reply = seven.bitcast_to_string(self.monitor_server.get_normal_packet())
-        self.logger.info(f"Received reply {reply}")
-        return reply

diff  --git a/lldb/packages/Python/lldbsuite/test/lldbreverse.py b/lldb/packages/Python/lldbsuite/test/lldbreverse.py
deleted file mode 100644
index 0f02fdffbdeada..00000000000000
--- a/lldb/packages/Python/lldbsuite/test/lldbreverse.py
+++ /dev/null
@@ -1,418 +0,0 @@
-import os
-import os.path
-import lldb
-from lldbsuite.test.lldbtest import *
-from lldbsuite.test.gdbclientutils import *
-from lldbsuite.test.lldbgdbproxy import *
-import lldbgdbserverutils
-import re
-
-
-class ThreadSnapshot:
-    def __init__(self, thread_id, registers):
-        self.thread_id = thread_id
-        self.registers = registers
-
-
-class MemoryBlockSnapshot:
-    def __init__(self, address, data):
-        self.address = address
-        self.data = data
-
-
-class StateSnapshot:
-    def __init__(self, thread_snapshots, memory):
-        self.thread_snapshots = thread_snapshots
-        self.memory = memory
-        self.thread_id = None
-
-
-class RegisterInfo:
-    def __init__(self, lldb_index, bitsize, little_endian):
-        self.lldb_index = lldb_index
-        self.bitsize = bitsize
-        self.little_endian = little_endian
-
-
-BELOW_STACK_POINTER = 16384
-ABOVE_STACK_POINTER = 4096
-
-BLOCK_SIZE = 1024
-
-SOFTWARE_BREAKPOINTS = 0
-HARDWARE_BREAKPOINTS = 1
-WRITE_WATCHPOINTS = 2
-
-
-class ReverseTestBase(GDBProxyTestBase):
-    """
-    Base class for tests that need reverse execution.
-
-    This class uses a gdbserver proxy to add very limited reverse-
-    execution capability to lldb-server/debugserver for testing
-    purposes only.
-
-    To use this class, run the inferior forward until some stopping point.
-    Then call `start_recording()` and execute forward again until reaching
-    a software breakpoint; this class records the state before each execution executes.
-    At that point, the server will accept "bc" and "bs" packets to step
-    backwards through the state.
-    When executing during recording, we only allow single-step and continue without
-    delivering a signal, and only software breakpoint stops are allowed.
-
-    We assume that while recording is enabled, the only effects of instructions
-    are on general-purpose registers (read/written by the 'g' and 'G' packets)
-    and on memory bytes between [SP - BELOW_STACK_POINTER, SP + ABOVE_STACK_POINTER).
-    """
-
-    """
-    A list of StateSnapshots in time order.
-
-    There is one snapshot per single-stepped instruction,
-    representing the state before that instruction was
-    executed. The last snapshot in the list is the
-    snapshot before the last instruction was executed.
-    This is an undo log; we snapshot a superset of the state that may have
-    been changed by the instruction's execution.
-    """
-    snapshots = None
-    recording_enabled = False
-
-    breakpoints = None
-
-    pid = None
-
-    pc_register_info = None
-    sp_register_info = None
-    general_purpose_register_info = None
-
-    def __init__(self, *args, **kwargs):
-        GDBProxyTestBase.__init__(self, *args, **kwargs)
-        self.breakpoints = [set(), set(), set(), set(), set()]
-
-    def respond(self, packet):
-        if not packet:
-            raise ValueError("Invalid empty packet")
-        if packet == self.server.PACKET_INTERRUPT:
-            # Don't send a response. We'll just run to completion.
-            return []
-        if self.is_command(packet, "qSupported", ":"):
-            reply = self.pass_through(packet)
-            return reply + ";ReverseStep+;ReverseContinue+"
-        if self.is_command(packet, "vCont", ";"):
-            if self.recording_enabled:
-                return self.continue_with_recording(packet)
-            snapshots = []
-        if packet[0] == "c" or packet[0] == "s" or packet[0] == "C" or packet[0] == "S":
-            raise ValueError("LLDB should not be sending old-style continuation packets")
-        if packet == "bc":
-            return self.reverse_continue()
-        if packet == "bs":
-            return self.reverse_step()
-        if packet == 'jThreadsInfo':
-            # Suppress this because it contains thread stop reasons which we might
-            # need to modify, and we don't want to have to implement that.
-            return ""
-        if packet[0] == "z" or packet[0] == "Z":
-            reply = self.pass_through(packet)
-            if reply == "OK":
-                self.update_breakpoints(packet)
-            return reply
-        return GDBProxyTestBase.respond(self, packet)
-
-    def start_recording(self):
-        self.recording_enabled = True
-        self.snapshots = []
-
-    def stop_recording(self):
-        """
-        Don't record when executing foward.
-
-        Reverse execution is still supported until the next forward continue.
-        """
-        self.recording_enabled = False
-
-    def is_command(self, packet, cmd, follow_token):
-        return packet == cmd or packet[0:len(cmd) + 1] == cmd + follow_token
-
-    def update_breakpoints(self, packet):
-        m = re.match("([zZ])([01234]),([0-9a-f]+),([0-9a-f]+)", packet)
-        if m is None:
-            raise ValueError("Invalid breakpoint packet: " + packet)
-        t = int(m.group(2))
-        addr = int(m.group(3), 16)
-        kind = int(m.group(4), 16)
-        if m.group(1) == 'Z':
-            self.breakpoints[t].add((addr, kind))
-        else:
-            self.breakpoints[t].discard((addr, kind))
-
-    def breakpoint_triggered_at(self, pc):
-        if any(addr == pc for addr, kind in self.breakpoints[SOFTWARE_BREAKPOINTS]):
-            return True
-        if any(addr == pc for addr, kind in self.breakpoints[HARDWARE_BREAKPOINTS]):
-            return True
-        return False
-
-    def watchpoint_triggered(self, new_value_block, current_contents):
-        """Returns the address or None."""
-        for watch_addr, kind in breakpoints[WRITE_WATCHPOINTS]:
-            for offset in range(0, kind):
-                addr = watch_addr + offset
-                if (addr >= new_value_block.address and
-                    addr < new_value_block.address + len(new_value_block.data)):
-                    index = addr - new_value_block.address
-                    if new_value_block.data[index*2:(index + 1)*2] != current_contents[index*2:(index + 1)*2]:
-                        return watch_addr
-        return None
-
-    def continue_with_recording(self, packet):
-        self.logger.debug("Continue with recording enabled")
-
-        step_packet = "vCont;s"
-        if packet == "vCont":
-            requested_step = False
-        else:
-            m = re.match("vCont;(c|s)(.*)", packet)
-            if m is None:
-                raise ValueError("Unsupported vCont packet: " + packet)
-            requested_step = m.group(1) == 's'
-            step_packet += m.group(2)
-
-        while True:
-            snapshot = self.capture_snapshot()
-            reply = self.pass_through(step_packet)
-            (stop_signal, stop_pairs) = self.parse_stop(reply)
-            if stop_signal != 5:
-                raise ValueError("Unexpected stop signal: " + reply)
-            is_swbreak = False
-            thread_id = None
-            for key, value in stop_pairs.items():
-                if key == "thread":
-                    thread_id = self.parse_thread_id(value)
-                    continue
-                if re.match('[0-9a-f]+', key):
-                    continue
-                if key == "swbreak" or (key == "reason" and value == "breakpoint"):
-                    is_swbreak = True
-                    continue
-                if key in ["name", "threads", "thread-pcs", "reason"]:
-                    continue
-                raise ValueError(f"Unknown stop key '{key}' in {reply}")
-            if is_swbreak:
-                self.logger.debug("Recording stopped")
-                return reply
-            if thread_id is None:
-                return ValueError("Expected thread ID: " + reply)
-            snapshot.thread_id = thread_id
-            self.snapshots.append(snapshot)
-            if requested_step:
-                self.logger.debug("Recording stopped for step")
-                return reply
-
-    def parse_stop(self, reply):
-        result = {}
-        if not reply:
-            raise ValueError("Invalid empty packet")
-        if reply[0] == "T" and len(reply) >= 3:
-            result = {k:v for k, v in self.parse_pairs(reply[3:])}
-            return (int(reply[1:3], 16), result)
-        raise "Unsupported stop reply: " + reply
-
-    def parse_pairs(self, text):
-        for pair in text.split(";"):
-            if not pair:
-                continue
-            m = re.match("([^:]+):(.*)", pair)
-            if m is None:
-                raise ValueError("Invalid pair text: " + text)
-            yield (m.group(1), m.group(2))
-
-    def capture_snapshot(self):
-        """Snapshot all threads and their stack memories."""
-        self.ensure_register_info()
-        current_thread = self.get_current_thread()
-        thread_snapshots = []
-        memory = []
-        for thread_id in self.get_thread_list():
-            registers = {}
-            for index in sorted(self.general_purpose_register_info.keys()):
-                reply =  self.pass_through(f"p{index:x};thread:{thread_id:x};")
-                if reply == "" or reply[0] == 'E':
-                    raise ValueError("Can't read register")
-                registers[index] = reply
-            thread_snapshot = ThreadSnapshot(thread_id, registers)
-            thread_sp = self.get_register(self.sp_register_info, thread_snapshot.registers)
-            memory += self.read_memory(thread_sp - BELOW_STACK_POINTER, thread_sp + ABOVE_STACK_POINTER)
-            thread_snapshots.append(thread_snapshot)
-        self.set_current_thread(current_thread)
-        return StateSnapshot(thread_snapshots, memory)
-
-    def restore_snapshot(self, snapshot):
-        """
-        Restore the snapshot during reverse execution.
-
-        If this triggers a breakpoint or watchpoint, return the stop reply,
-        otherwise None.
-        """
-        current_thread = self.get_current_thread()
-        stop_reasons = []
-        for thread_snapshot in snapshot.thread_snapshots:
-            thread_id = thread_snapshot.thread_id
-            for lldb_index in sorted(thread_snapshot.registers.keys()):
-                data = thread_snapshot.registers[lldb_index]
-                reply = self.pass_through(f"P{lldb_index:x}={data};thread:{thread_id:x};")
-                if reply != "OK":
-                    raise ValueError("Can't restore thread register")
-            if thread_id == snapshot.thread_id:
-                new_pc = self.get_register(self.pc_register_info, thread_snapshot.registers)
-                if self.breakpoint_triggered_at(new_pc):
-                    stop_reasons.append([("reason", "breakpoint")])
-        self.set_current_thread(current_thread)
-        for block in snapshot.memory:
-            current_memory = self.pass_through(f"m{block.address:x},{(len(block.data)/2):x}")
-            if not current_memory or current_memory[0] == 'E':
-                raise ValueError("Can't read back memory")
-            reply = self.pass_through(f"M{block.address:x},{len(block.data)/2:x}:" + block.data)
-            if reply != "OK":
-                raise ValueError("Can't restore memory")
-            watch_addr = self.watchpoint_triggered(block, current_memory[1:])
-            if watch_addr is not None:
-                stop_reasons.append([("reason", "watchpoint"), ("watch", f"{watch_addr:x}")])
-        if stop_reasons:
-            pairs = ";".join(f"{key}:{value}" for key, value in stop_reasons[0])
-            return f"T05thread:{self.pid:x}.{snapshot.thread_id:x};{pairs};"
-        return None
-
-    def reverse_step(self):
-        if not self.snapshots:
-            self.logger.debug("Reverse-step at history boundary")
-            return self.history_boundary_reply(self.get_current_thread())
-        self.logger.debug("Reverse-step started")
-        snapshot = self.snapshots.pop()
-        stop_reply = self.restore_snapshot(snapshot)
-        self.set_current_thread(snapshot.thread_id)
-        self.logger.debug("Reverse-step stopped")
-        if stop_reply is None:
-            return self.singlestep_stop_reply(snapshot.thread_id)
-        return stop_reply
-
-    def reverse_continue(self):
-        self.logger.debug("Reverse-continue started")
-        thread_id = None
-        while self.snapshots:
-            snapshot = self.snapshots.pop()
-            stop_reply = self.restore_snapshot(snapshot)
-            thread_id = snapshot.thread_id
-            if stop_reply is not None:
-                self.set_current_thread(thread_id)
-                self.logger.debug("Reverse-continue stopped")
-                return stop_reply
-        if thread_id is None:
-            thread_id = self.get_current_thread()
-        else:
-            self.set_current_thread(snapshot.thread_id)
-        self.logger.debug("Reverse-continue stopped at history boundary")
-        return self.history_boundary_reply(thread_id)
-
-    def get_current_thread(self):
-        reply = self.pass_through("qC")
-        return self.parse_thread_id(reply[2:])
-
-    def parse_thread_id(self, thread_id):
-        m = re.match("(p([0-9a-f]+)[.])?([0-9a-f]+)$", thread_id)
-        if m is None:
-            raise ValueError("Invalid thread ID: " + thread_id)
-        if self.pid is None:
-            self.pid = int(m.group(2), 16)
-        return int(m.group(3), 16)
-
-    def history_boundary_reply(self, thread_id):
-        return f"T00thread:{self.pid:x}.{thread_id:x};replaylog:begin;"
-
-    def singlestep_stop_reply(self, thread_id):
-        return f"T05thread:{self.pid:x}.{thread_id:x};"
-
-    def set_current_thread(self, thread_id):
-        """
-        Set current thread in inner gdbserver.
-        """
-        if thread_id >= 0:
-            self.pass_through(f"Hg{self.pid:x}.{thread_id:x}")
-            self.pass_through(f"Hc{self.pid:x}.{thread_id:x}")
-        else:
-            self.pass_through(f"Hc-1.-1")
-            self.pass_through(f"Hg-1.-1")
-
-    def get_register(self, register_info, registers):
-        if register_info.bitsize % 8 != 0:
-            raise ValueError("Register size must be a multiple of 8 bits")
-        if register_info.lldb_index not in registers:
-            raise ValueError("Register value not captured")
-        data = registers[register_info.lldb_index]
-        num_bytes = register_info.bitsize//8
-        bytes = []
-        for i in range(0, num_bytes):
-            bytes.append(int(data[i*2:(i + 1)*2], 16))
-        if register_info.little_endian:
-            bytes.reverse()
-        result = 0
-        for byte in bytes:
-            result = (result << 8) + byte
-        return result
-
-    def read_memory(self, start_addr, end_addr):
-        """
-        Read a region of memory from the target.
-
-        Some of the addresses may extend into invalid virtual memory;
-        skip those areas.
-        Return a list of blocks containing the valid area(s) in the
-        requested range.
-        """
-        regions = []
-        start_addr = start_addr & (BLOCK_SIZE - 1)
-        end_addr = (end_addr + BLOCK_SIZE - 1) & (BLOCK_SIZE - 1)
-        for addr in range(start_addr, end_addr, BLOCK_SIZE):
-            reply = self.pass_through(f"m{addr:x},{(BLOCK_SIZE - 1):x}")
-            if reply and reply[0] != 'E':
-                block = MemoryBlockSnapshot(addr, reply[1:])
-                regions.append(block)
-        return regions
-
-    def ensure_register_info(self):
-        if self.general_purpose_register_info is not None:
-            return
-        reply = self.pass_through("qHostInfo")
-        little_endian = any(kv == ("endian", "little") for kv in self.parse_pairs(reply))
-        self.general_purpose_register_info = {}
-        lldb_index = 0
-        while True:
-            reply = self.pass_through(f"qRegisterInfo{lldb_index:x}")
-            if not reply or reply[0] == 'E':
-                break
-            info = {k:v for k, v in self.parse_pairs(reply)}
-            reg_info = RegisterInfo(lldb_index, int(info["bitsize"]), little_endian)
-            if info["set"] == "General Purpose Registers" and not "container-regs" in info:
-                self.general_purpose_register_info[lldb_index] = reg_info
-            if "generic" in info:
-                if info["generic"] == "pc":
-                    self.pc_register_info = reg_info
-                elif info["generic"] == "sp":
-                    self.sp_register_info = reg_info
-            lldb_index += 1
-        if self.pc_register_info is None or self.sp_register_info is None:
-            raise ValueError("Can't find generic pc or sp register")
-
-    def get_thread_list(self):
-        threads = []
-        reply = self.pass_through("qfThreadInfo")
-        while True:
-            if not reply:
-                raise ValueError("Missing reply packet")
-            if reply[0] == 'm':
-                for id in reply[1:].split(","):
-                    threads.append(self.parse_thread_id(id))
-            elif reply[0] == 'l':
-                return threads
-            reply = self.pass_through("qsThreadInfo")

diff  --git a/lldb/packages/Python/lldbsuite/test/lldbtest.py b/lldb/packages/Python/lldbsuite/test/lldbtest.py
index 7cc1ac9749ec93..8884ef5933ada8 100644
--- a/lldb/packages/Python/lldbsuite/test/lldbtest.py
+++ b/lldb/packages/Python/lldbsuite/test/lldbtest.py
@@ -143,8 +143,6 @@
 
 STOPPED_DUE_TO_WATCHPOINT = "Process should be stopped due to watchpoint"
 
-STOPPED_DUE_TO_HISTORY_BOUNDARY = "Process should be stopped due to history boundary"
-
 DATA_TYPES_DISPLAYED_CORRECTLY = "Data type(s) displayed correctly"
 
 VALID_BREAKPOINT = "Got a valid breakpoint"

diff  --git a/lldb/source/API/SBProcess.cpp b/lldb/source/API/SBProcess.cpp
index 07780f9f9c8393..9773144723c34c 100644
--- a/lldb/source/API/SBProcess.cpp
+++ b/lldb/source/API/SBProcess.cpp
@@ -564,10 +564,6 @@ uint32_t SBProcess::GetAddressByteSize() const {
 }
 
 SBError SBProcess::Continue() {
-  return Continue(RunDirection::eRunForward);
-}
-
-SBError SBProcess::Continue(RunDirection direction) {
   LLDB_INSTRUMENT_VA(this);
 
   SBError sb_error;
@@ -578,9 +574,9 @@ SBError SBProcess::Continue(RunDirection direction) {
         process_sp->GetTarget().GetAPIMutex());
 
     if (process_sp->GetTarget().GetDebugger().GetAsyncExecution())
-      sb_error.ref() = process_sp->Resume(direction);
+      sb_error.ref() = process_sp->Resume();
     else
-      sb_error.ref() = process_sp->ResumeSynchronous(nullptr, direction);
+      sb_error.ref() = process_sp->ResumeSynchronous(nullptr);
   } else
     sb_error = Status::FromErrorString("SBProcess is invalid");
 

diff  --git a/lldb/source/API/SBThread.cpp b/lldb/source/API/SBThread.cpp
index aca8a039952960..a99456e06d0329 100644
--- a/lldb/source/API/SBThread.cpp
+++ b/lldb/source/API/SBThread.cpp
@@ -172,7 +172,6 @@ size_t SBThread::GetStopReasonDataCount() {
         case eStopReasonInstrumentation:
         case eStopReasonProcessorTrace:
         case eStopReasonVForkDone:
-        case eStopReasonHistoryBoundary:
           // There is no data for these stop reasons.
           return 0;
 
@@ -234,7 +233,6 @@ uint64_t SBThread::GetStopReasonDataAtIndex(uint32_t idx) {
         case eStopReasonInstrumentation:
         case eStopReasonProcessorTrace:
         case eStopReasonVForkDone:
-        case eStopReasonHistoryBoundary:
           // There is no data for these stop reasons.
           return 0;
 

diff  --git a/lldb/source/Interpreter/CommandInterpreter.cpp b/lldb/source/Interpreter/CommandInterpreter.cpp
index ea60492ac46a10..8d3a82ef6c990a 100644
--- a/lldb/source/Interpreter/CommandInterpreter.cpp
+++ b/lldb/source/Interpreter/CommandInterpreter.cpp
@@ -2553,8 +2553,7 @@ bool CommandInterpreter::DidProcessStopAbnormally() const {
     const StopReason reason = stop_info->GetStopReason();
     if (reason == eStopReasonException ||
         reason == eStopReasonInstrumentation ||
-        reason == eStopReasonProcessorTrace || reason == eStopReasonInterrupt ||
-        reason == eStopReasonHistoryBoundary)
+        reason == eStopReasonProcessorTrace || reason == eStopReasonInterrupt)
       return true;
 
     if (reason == eStopReasonSignal) {

diff  --git a/lldb/source/Plugins/Process/Linux/NativeThreadLinux.cpp b/lldb/source/Plugins/Process/Linux/NativeThreadLinux.cpp
index b0aa664775b463..de047ee214c11e 100644
--- a/lldb/source/Plugins/Process/Linux/NativeThreadLinux.cpp
+++ b/lldb/source/Plugins/Process/Linux/NativeThreadLinux.cpp
@@ -82,9 +82,6 @@ void LogThreadStopInfo(Log &log, const ThreadStopInfo &stop_info,
   case eStopReasonProcessorTrace:
     log.Printf("%s: %s processor trace", __FUNCTION__, header);
     return;
-  case eStopReasonHistoryBoundary:
-    log.Printf("%s: %s history boundary", __FUNCTION__, header);
-    return;
   default:
     log.Printf("%s: %s invalid stop reason %" PRIu32, __FUNCTION__, header,
                static_cast<uint32_t>(stop_info.reason));

diff  --git a/lldb/source/Plugins/Process/MacOSX-Kernel/ProcessKDP.cpp b/lldb/source/Plugins/Process/MacOSX-Kernel/ProcessKDP.cpp
index 116c43343c01d1..9b2907c6809965 100644
--- a/lldb/source/Plugins/Process/MacOSX-Kernel/ProcessKDP.cpp
+++ b/lldb/source/Plugins/Process/MacOSX-Kernel/ProcessKDP.cpp
@@ -402,16 +402,9 @@ lldb_private::DynamicLoader *ProcessKDP::GetDynamicLoader() {
 
 Status ProcessKDP::WillResume() { return Status(); }
 
-Status ProcessKDP::DoResume(RunDirection direction) {
+Status ProcessKDP::DoResume() {
   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();

diff  --git a/lldb/source/Plugins/Process/MacOSX-Kernel/ProcessKDP.h b/lldb/source/Plugins/Process/MacOSX-Kernel/ProcessKDP.h
index 1b71d83f70b087..e5ec5914f9600d 100644
--- a/lldb/source/Plugins/Process/MacOSX-Kernel/ProcessKDP.h
+++ b/lldb/source/Plugins/Process/MacOSX-Kernel/ProcessKDP.h
@@ -90,7 +90,7 @@ class ProcessKDP : public lldb_private::Process {
   // Process Control
   lldb_private::Status WillResume() override;
 
-  lldb_private::Status DoResume(lldb::RunDirection direction) override;
+  lldb_private::Status DoResume() override;
 
   lldb_private::Status DoHalt(bool &caused_stop) override;
 

diff  --git a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp
index 76b7095deaa503..703aa082f0476f 100644
--- a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp
+++ b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp
@@ -204,17 +204,11 @@ ProcessWindows::DoAttachToProcessWithID(lldb::pid_t pid,
   return error;
 }
 
-Status ProcessWindows::DoResume(RunDirection direction) {
+Status ProcessWindows::DoResume() {
   Log *log = GetLog(WindowsLog::Process);
   llvm::sys::ScopedLock lock(m_mutex);
   Status error;
 
-  if (direction == RunDirection::eRunReverse) {
-    error.SetErrorStringWithFormatv(
-        "error: {0} does not support reverse execution of processes", GetPluginName());
-    return error;
-  }
-
   StateType private_state = GetPrivateState();
   if (private_state == eStateStopped || private_state == eStateCrashed) {
     LLDB_LOG(log, "process {0} is in state {1}.  Resuming...",

diff  --git a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.h b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.h
index 97284b7cd1436e..e97cfb790248be 100644
--- a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.h
+++ b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.h
@@ -52,7 +52,7 @@ class ProcessWindows : public Process, public ProcessDebugger {
   Status DoAttachToProcessWithID(
       lldb::pid_t pid,
       const lldb_private::ProcessAttachInfo &attach_info) override;
-  Status DoResume(lldb::RunDirection direction) override;
+  Status DoResume() override;
   Status DoDestroy() override;
   Status DoHalt(bool &caused_stop) override;
 

diff  --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
index fc792a4409410b..e42526c8fd7266 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
@@ -199,20 +199,6 @@ uint64_t GDBRemoteCommunicationClient::GetRemoteMaxPacketSize() {
   return m_max_packet_size;
 }
 
-bool GDBRemoteCommunicationClient::GetReverseContinueSupported() {
-  if (m_supports_reverse_continue == eLazyBoolCalculate) {
-    GetRemoteQSupported();
-  }
-  return m_supports_reverse_continue == eLazyBoolYes;
-}
-
-bool GDBRemoteCommunicationClient::GetReverseStepSupported() {
-  if (m_supports_reverse_step == eLazyBoolCalculate) {
-    GetRemoteQSupported();
-  }
-  return m_supports_reverse_step == eLazyBoolYes;
-}
-
 bool GDBRemoteCommunicationClient::QueryNoAckModeSupported() {
   if (m_supports_not_sending_acks == eLazyBoolCalculate) {
     m_send_acks = true;
@@ -309,8 +295,6 @@ void GDBRemoteCommunicationClient::ResetDiscoverableSettings(bool did_exec) {
     m_supports_qXfer_siginfo_read = eLazyBoolCalculate;
     m_supports_augmented_libraries_svr4_read = eLazyBoolCalculate;
     m_uses_native_signals = eLazyBoolCalculate;
-    m_supports_reverse_continue = eLazyBoolCalculate;
-    m_supports_reverse_step = eLazyBoolCalculate;
     m_supports_qProcessInfoPID = true;
     m_supports_qfProcessInfo = true;
     m_supports_qUserName = true;
@@ -364,8 +348,6 @@ void GDBRemoteCommunicationClient::GetRemoteQSupported() {
   m_supports_memory_tagging = eLazyBoolNo;
   m_supports_qSaveCore = eLazyBoolNo;
   m_uses_native_signals = eLazyBoolNo;
-  m_supports_reverse_continue = eLazyBoolNo;
-  m_supports_reverse_step = eLazyBoolNo;
 
   m_max_packet_size = UINT64_MAX; // It's supposed to always be there, but if
                                   // not, we assume no limit
@@ -419,10 +401,6 @@ void GDBRemoteCommunicationClient::GetRemoteQSupported() {
         m_supports_qSaveCore = eLazyBoolYes;
       else if (x == "native-signals+")
         m_uses_native_signals = eLazyBoolYes;
-      else if (x == "ReverseContinue+")
-        m_supports_reverse_continue = eLazyBoolYes;
-      else if (x == "ReverseStep+")
-        m_supports_reverse_step = eLazyBoolYes;
       // Look for a list of compressions in the features list e.g.
       // qXfer:features:read+;PacketSize=20000;qEcho+;SupportedCompressions=zlib-
       // deflate,lzma

diff  --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h
index 116b47c1edf033..898d176abc3465 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h
@@ -331,10 +331,6 @@ class GDBRemoteCommunicationClient : public GDBRemoteClientBase {
 
   bool GetMultiprocessSupported();
 
-  bool GetReverseContinueSupported();
-
-  bool GetReverseStepSupported();
-
   LazyBool SupportsAllocDeallocMemory() // const
   {
     // Uncomment this to have lldb pretend the debug server doesn't respond to
@@ -565,8 +561,6 @@ class GDBRemoteCommunicationClient : public GDBRemoteClientBase {
   LazyBool m_supports_memory_tagging = eLazyBoolCalculate;
   LazyBool m_supports_qSaveCore = eLazyBoolCalculate;
   LazyBool m_uses_native_signals = eLazyBoolCalculate;
-  LazyBool m_supports_reverse_continue = eLazyBoolCalculate;
-  LazyBool m_supports_reverse_step = eLazyBoolCalculate;
 
   bool m_supports_qProcessInfoPID : 1, m_supports_qfProcessInfo : 1,
       m_supports_qUserName : 1, m_supports_qGroupName : 1,

diff  --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp
index 4016cde74ebea8..35fa93e53bc66f 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp
@@ -716,7 +716,6 @@ static const char *GetStopReasonString(StopReason stop_reason) {
     return "vforkdone";
   case eStopReasonInterrupt:
     return "async interrupt";
-  case eStopReasonHistoryBoundary:
   case eStopReasonInstrumentation:
   case eStopReasonInvalid:
   case eStopReasonPlanComplete:

diff  --git a/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp b/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
index 3fc03bd05d5df0..3e09c316d74f44 100644
--- a/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
@@ -169,10 +169,6 @@ class PluginProperties : public Properties {
   }
 };
 
-std::chrono::seconds ResumeTimeout() {
-  return std::chrono::seconds(5);
-}
-
 } // namespace
 
 static PluginProperties &GetGlobalPluginProperties() {
@@ -1184,11 +1180,10 @@ Status ProcessGDBRemote::WillResume() {
   return Status();
 }
 
-Status ProcessGDBRemote::DoResume(RunDirection direction) {
+Status ProcessGDBRemote::DoResume() {
   Status error;
   Log *log = GetLog(GDBRLog::Process);
-  LLDB_LOGF(log, "ProcessGDBRemote::Resume(%s)",
-            direction == RunDirection::eRunForward ? "" : "reverse");
+  LLDB_LOGF(log, "ProcessGDBRemote::Resume()");
 
   ListenerSP listener_sp(
       Listener::MakeListener("gdb-remote.resume-packet-sent"));
@@ -1202,21 +1197,12 @@ Status ProcessGDBRemote::DoResume(RunDirection direction) {
 
     StreamString continue_packet;
     bool continue_packet_error = false;
-    // Number of threads continuing with "c", i.e. continuing without a signal to deliver.
-    const size_t num_continue_c_tids = m_continue_c_tids.size();
-    // Number of threads continuing with "C", i.e. continuing with a signal to deliver.
-    const size_t num_continue_C_tids = m_continue_C_tids.size();
-    // Number of threads continuing with "s", i.e. single-stepping.
-    const size_t num_continue_s_tids = m_continue_s_tids.size();
-    // Number of threads continuing with "S", i.e. single-stepping with a signal to deliver.
-    const size_t num_continue_S_tids = m_continue_S_tids.size();
-    if (direction == RunDirection::eRunForward &&
-        m_gdb_comm.HasAnyVContSupport()) {
+    if (m_gdb_comm.HasAnyVContSupport()) {
       std::string pid_prefix;
       if (m_gdb_comm.GetMultiprocessSupported())
         pid_prefix = llvm::formatv("p{0:x-}.", GetID());
 
-      if (num_continue_c_tids == num_threads ||
+      if (m_continue_c_tids.size() == num_threads ||
           (m_continue_c_tids.empty() && m_continue_C_tids.empty() &&
            m_continue_s_tids.empty() && m_continue_S_tids.empty())) {
         // All threads are continuing
@@ -1279,11 +1265,14 @@ Status ProcessGDBRemote::DoResume(RunDirection direction) {
     } else
       continue_packet_error = true;
 
-    if (direction == RunDirection::eRunForward && continue_packet_error) {
+    if (continue_packet_error) {
       // Either no vCont support, or we tried to use part of the vCont packet
-      // that wasn't supported by the remote GDB server, or it's the reverse
-      // direction. We need to try and make a simple packet that can do our
-      // continue.
+      // that wasn't supported by the remote GDB server. We need to try and
+      // make a simple packet that can do our continue
+      const size_t num_continue_c_tids = m_continue_c_tids.size();
+      const size_t num_continue_C_tids = m_continue_C_tids.size();
+      const size_t num_continue_s_tids = m_continue_s_tids.size();
+      const size_t num_continue_S_tids = m_continue_S_tids.size();
       if (num_continue_c_tids > 0) {
         if (num_continue_c_tids == num_threads) {
           // All threads are resuming...
@@ -1374,41 +1363,9 @@ Status ProcessGDBRemote::DoResume(RunDirection direction) {
       }
     }
 
-    if (direction == RunDirection::eRunReverse && continue_packet_error) {
-      if (num_continue_C_tids > 0 || num_continue_S_tids > 0) {
-        LLDB_LOGF(log, "ProcessGDBRemote::DoResumeReverse: Signals not supported");
-        return Status::FromErrorString("can't deliver signals while running in reverse");
-      }
-
-      if (num_continue_s_tids > 0) {
-        if (num_continue_s_tids > 1) {
-          LLDB_LOGF(log, "ProcessGDBRemote::DoResumeReverse: can't step multiple threads");
-          return Status::FromErrorString("can't step multiple threads while reverse-stepping");
-        }
-
-        if (!m_gdb_comm.GetReverseStepSupported()) {
-          LLDB_LOGF(log, "ProcessGDBRemote::DoResumeReverse: target does not support reverse-stepping");
-          return Status::FromErrorString("target does not support reverse-stepping");
-        }
-
-        m_gdb_comm.SetCurrentThreadForRun(m_continue_s_tids.front());
-        continue_packet.PutCString("bs");
-      } else {
-        if (!m_gdb_comm.GetReverseContinueSupported()) {
-          LLDB_LOGF(log, "ProcessGDBRemote::DoResumeReverse: target does not support reverse-continue");
-          return Status::FromErrorString("target does not support reverse-continue");
-        }
-
-        // All threads continue whether requested or not ---
-        // we can't change how threads ran in the past.
-        continue_packet.PutCString("bc");
-      }
-
-      continue_packet_error = false;
-    }
-
     if (continue_packet_error) {
-      return Status::FromErrorString("can't make continue packet for this resume");
+      error =
+          Status::FromErrorString("can't make continue packet for this resume");
     } else {
       EventSP event_sp;
       if (!m_async_thread.IsJoinable()) {
@@ -1423,7 +1380,7 @@ Status ProcessGDBRemote::DoResume(RunDirection direction) {
           std::make_shared<EventDataBytes>(continue_packet.GetString());
       m_async_broadcaster.BroadcastEvent(eBroadcastBitAsyncContinue, data_sp);
 
-      if (!listener_sp->GetEvent(event_sp, ResumeTimeout())) {
+      if (!listener_sp->GetEvent(event_sp, std::chrono::seconds(5))) {
         error = Status::FromErrorString("Resume timed out.");
         LLDB_LOGF(log, "ProcessGDBRemote::DoResume: Resume timed out.");
       } else if (event_sp->BroadcasterIs(&m_async_broadcaster)) {
@@ -1906,10 +1863,6 @@ ThreadSP ProcessGDBRemote::SetThreadStopInfo(
           thread_sp->SetStopInfo(StopInfo::CreateStopReasonWithException(
               *thread_sp, description.c_str()));
           handled = true;
-        } else if (reason == "replaylog") {
-          thread_sp->SetStopInfo(StopInfo::CreateStopReasonHistoryBoundary(
-              *thread_sp, description.c_str()));
-          handled = true;
         } else if (reason == "exec") {
           did_exec = true;
           thread_sp->SetStopInfo(
@@ -2365,8 +2318,6 @@ StateType ProcessGDBRemote::SetThreadStopInfo(StringExtractor &stop_packet) {
         description = std::string(ostr.GetString());
       } else if (key.compare("swbreak") == 0 || key.compare("hwbreak") == 0) {
         reason = "breakpoint";
-      } else if (key.compare("replaylog") == 0) {
-        reason = "replaylog";
       } else if (key.compare("library") == 0) {
         auto error = LoadModules();
         if (error) {

diff  --git a/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.h b/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.h
index fa3e1cec76e2b3..2492795851388a 100644
--- a/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.h
+++ b/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.h
@@ -111,7 +111,7 @@ class ProcessGDBRemote : public Process,
   // Process Control
   Status WillResume() override;
 
-  Status DoResume(lldb::RunDirection direction) override;
+  Status DoResume() override;
 
   Status DoHalt(bool &caused_stop) override;
 

diff  --git a/lldb/source/Plugins/Process/scripted/ScriptedProcess.cpp b/lldb/source/Plugins/Process/scripted/ScriptedProcess.cpp
index 304c12173dd35d..d2111ce877ce55 100644
--- a/lldb/source/Plugins/Process/scripted/ScriptedProcess.cpp
+++ b/lldb/source/Plugins/Process/scripted/ScriptedProcess.cpp
@@ -182,15 +182,10 @@ void ScriptedProcess::DidResume() {
   m_pid = GetInterface().GetProcessID();
 }
 
-Status ScriptedProcess::DoResume(RunDirection direction) {
+Status ScriptedProcess::DoResume() {
   LLDB_LOGF(GetLog(LLDBLog::Process), "ScriptedProcess::%s resuming process", __FUNCTION__);
 
-  if (direction == RunDirection::eRunForward) {
-    return GetInterface().Resume();
-  } else {
-    return Status::FromErrorStringWithFormatv(
-        "error: {0} does not support reverse execution of processes", GetPluginName());
-  }
+  return GetInterface().Resume();
 }
 
 Status ScriptedProcess::DoAttach(const ProcessAttachInfo &attach_info) {

diff  --git a/lldb/source/Plugins/Process/scripted/ScriptedProcess.h b/lldb/source/Plugins/Process/scripted/ScriptedProcess.h
index 8ebe4ca5f3d449..0335364b4010b2 100644
--- a/lldb/source/Plugins/Process/scripted/ScriptedProcess.h
+++ b/lldb/source/Plugins/Process/scripted/ScriptedProcess.h
@@ -52,7 +52,7 @@ class ScriptedProcess : public Process {
 
   void DidResume() override;
 
-  Status DoResume(lldb::RunDirection direction) override;
+  Status DoResume() override;
 
   Status DoAttachToProcessWithID(lldb::pid_t pid,
                                  const ProcessAttachInfo &attach_info) override;

diff  --git a/lldb/source/Target/Process.cpp b/lldb/source/Target/Process.cpp
index ff6a2f59eba35f..aca08972811470 100644
--- a/lldb/source/Target/Process.cpp
+++ b/lldb/source/Target/Process.cpp
@@ -446,8 +446,7 @@ Process::Process(lldb::TargetSP target_sp, ListenerSP listener_sp,
       m_memory_cache(*this), m_allocated_memory_cache(*this),
       m_should_detach(false), m_next_event_action_up(), m_public_run_lock(),
       m_private_run_lock(), m_currently_handling_do_on_removals(false),
-      m_resume_requested(false), m_last_run_direction(eRunForward),
-      m_interrupt_tid(LLDB_INVALID_THREAD_ID),
+      m_resume_requested(false), m_interrupt_tid(LLDB_INVALID_THREAD_ID),
       m_finalizing(false), m_destructing(false),
       m_clear_thread_plans_on_stop(false), m_force_next_event_delivery(false),
       m_last_broadcast_state(eStateInvalid), m_destroy_in_process(false),
@@ -846,7 +845,6 @@ bool Process::HandleProcessStateChangedEvent(
             switch (thread_stop_reason) {
             case eStopReasonInvalid:
             case eStopReasonNone:
-            case eStopReasonHistoryBoundary:
               break;
 
             case eStopReasonSignal: {
@@ -1354,7 +1352,7 @@ void Process::SetPublicState(StateType new_state, bool restarted) {
   }
 }
 
-Status Process::Resume(RunDirection direction) {
+Status Process::Resume() {
   Log *log(GetLog(LLDBLog::State | LLDBLog::Process));
   LLDB_LOGF(log, "(plugin = %s) -- locking run lock", GetPluginName().data());
   if (!m_public_run_lock.TrySetRunning()) {
@@ -1363,7 +1361,7 @@ Status Process::Resume(RunDirection direction) {
     return Status::FromErrorString(
         "Resume request failed - process still running.");
   }
-  Status error = PrivateResume(direction);
+  Status error = PrivateResume();
   if (!error.Success()) {
     // Undo running state change
     m_public_run_lock.SetStopped();
@@ -1371,7 +1369,7 @@ Status Process::Resume(RunDirection direction) {
   return error;
 }
 
-Status Process::ResumeSynchronous(Stream *stream, RunDirection direction) {
+Status Process::ResumeSynchronous(Stream *stream) {
   Log *log(GetLog(LLDBLog::State | LLDBLog::Process));
   LLDB_LOGF(log, "Process::ResumeSynchronous -- locking run lock");
   if (!m_public_run_lock.TrySetRunning()) {
@@ -1384,7 +1382,7 @@ Status Process::ResumeSynchronous(Stream *stream, RunDirection direction) {
       Listener::MakeListener(ResumeSynchronousHijackListenerName.data()));
   HijackProcessEvents(listener_sp);
 
-  Status error = PrivateResume(direction);
+  Status error = PrivateResume();
   if (error.Success()) {
     StateType state =
         WaitForProcessToStop(std::nullopt, nullptr, true, listener_sp, stream,
@@ -3241,7 +3239,7 @@ Status Process::ConnectRemote(llvm::StringRef remote_url) {
   return error;
 }
 
-Status Process::PrivateResume(RunDirection direction) {
+Status Process::PrivateResume() {
   Log *log(GetLog(LLDBLog::Process | LLDBLog::Step));
   LLDB_LOGF(log,
             "Process::PrivateResume() m_stop_id = %u, public state: %s "
@@ -3257,15 +3255,6 @@ Status Process::PrivateResume(RunDirection direction) {
   if (!GetModID().IsLastResumeForUserExpression())
     ResetExtendedCrashInfoDict();
 
-  if (m_last_run_direction != direction) {
-    // In the future we might want to support mixed-direction plans,
-    // e.g. a forward step-over stops at a breakpoint, the user does
-    // a reverse-step, then disables the breakpoint and continues forward.
-    // This code will need to be changed to support that.
-    m_thread_list.DiscardThreadPlans();
-    m_last_run_direction = direction;
-  }
-
   Status error(WillResume());
   // Tell the process it is about to resume before the thread list
   if (error.Success()) {
@@ -3283,7 +3272,7 @@ Status Process::PrivateResume(RunDirection direction) {
             "Process::PrivateResume PreResumeActions failed, not resuming.");
       } else {
         m_mod_id.BumpResumeID();
-        error = DoResume(direction);
+        error = DoResume();
         if (error.Success()) {
           DidResume();
           m_thread_list.DidResume();
@@ -3746,7 +3735,7 @@ bool Process::ShouldBroadcastEvent(Event *event_ptr) {
                     "from state: %s",
                     static_cast<void *>(event_ptr), StateAsCString(state));
           ProcessEventData::SetRestartedInEvent(event_ptr, true);
-          PrivateResume(m_last_run_direction);
+          PrivateResume();
         }
       } else {
         return_value = true;
@@ -4357,7 +4346,7 @@ void Process::ProcessEventData::DoOnRemoval(Event *event_ptr) {
     SetRestarted(true);
     // Use the private resume method here, since we aren't changing the run
     // lock state.
-    process_sp->PrivateResume(process_sp->m_last_run_direction);
+    process_sp->PrivateResume();
   } else {
     bool hijacked = process_sp->IsHijackedForEvent(eBroadcastBitStateChanged) &&
                     !process_sp->StateChangedIsHijackedForSynchronousResume();

diff  --git a/lldb/source/Target/StopInfo.cpp b/lldb/source/Target/StopInfo.cpp
index 08e9a7c099bad2..bd7032b803df90 100644
--- a/lldb/source/Target/StopInfo.cpp
+++ b/lldb/source/Target/StopInfo.cpp
@@ -1212,30 +1212,6 @@ class StopInfoProcessorTrace : public StopInfo {
   }
 };
 
-// StopInfoHistoryBoundary
-
-class StopInfoHistoryBoundary : public StopInfo {
-public:
-  StopInfoHistoryBoundary(Thread &thread, const char *description)
-      : StopInfo(thread, LLDB_INVALID_UID) {
-    if (description)
-      SetDescription(description);
-  }
-
-  ~StopInfoHistoryBoundary() override = default;
-
-  StopReason GetStopReason() const override {
-    return eStopReasonHistoryBoundary;
-  }
-
-  const char *GetDescription() override {
-    if (m_description.empty())
-      return "history boundary";
-    else
-      return m_description.c_str();
-  }
-};
-
 // StopInfoThreadPlan
 
 class StopInfoThreadPlan : public StopInfo {
@@ -1463,11 +1439,6 @@ StopInfoSP StopInfo::CreateStopReasonProcessorTrace(Thread &thread,
   return StopInfoSP(new StopInfoProcessorTrace(thread, description));
 }
 
-StopInfoSP StopInfo::CreateStopReasonHistoryBoundary(Thread &thread,
-                                                     const char *description) {
-  return StopInfoSP(new StopInfoHistoryBoundary(thread, description));
-}
-
 StopInfoSP StopInfo::CreateStopReasonWithExec(Thread &thread) {
   return StopInfoSP(new StopInfoExec(thread));
 }

diff  --git a/lldb/source/Target/Thread.cpp b/lldb/source/Target/Thread.cpp
index bbb586f033b746..902fbb2b519ef7 100644
--- a/lldb/source/Target/Thread.cpp
+++ b/lldb/source/Target/Thread.cpp
@@ -624,12 +624,10 @@ void Thread::SetupForResume() {
     // what the current plan is.
 
     lldb::RegisterContextSP reg_ctx_sp(GetRegisterContext());
-    ProcessSP process_sp(GetProcess());
-    if (reg_ctx_sp && process_sp &&
-        process_sp->GetLastRunDirection() == eRunForward) {
+    if (reg_ctx_sp) {
       const addr_t thread_pc = reg_ctx_sp->GetPC();
       BreakpointSiteSP bp_site_sp =
-          process_sp->GetBreakpointSiteList().FindByAddress(thread_pc);
+          GetProcess()->GetBreakpointSiteList().FindByAddress(thread_pc);
       if (bp_site_sp) {
         // Note, don't assume there's a ThreadPlanStepOverBreakpoint, the
         // target may not require anything special to step over a breakpoint.
@@ -1734,8 +1732,6 @@ std::string Thread::StopReasonAsString(lldb::StopReason reason) {
     return "processor trace";
   case eStopReasonInterrupt:
     return "async interrupt";
-  case eStopReasonHistoryBoundary:
-    return "history boundary";
   }
 
   return "StopReason = " + std::to_string(reason);

diff  --git a/lldb/test/API/functionalities/reverse-execution/Makefile b/lldb/test/API/functionalities/reverse-execution/Makefile
deleted file mode 100644
index 10495940055b63..00000000000000
--- a/lldb/test/API/functionalities/reverse-execution/Makefile
+++ /dev/null
@@ -1,3 +0,0 @@
-C_SOURCES := main.c
-
-include Makefile.rules

diff  --git a/lldb/test/API/functionalities/reverse-execution/TestReverseContinueBreakpoints.py b/lldb/test/API/functionalities/reverse-execution/TestReverseContinueBreakpoints.py
deleted file mode 100644
index b37578fbd82468..00000000000000
--- a/lldb/test/API/functionalities/reverse-execution/TestReverseContinueBreakpoints.py
+++ /dev/null
@@ -1,115 +0,0 @@
-import lldb
-import time
-import unittest
-from lldbsuite.test.lldbtest import *
-from lldbsuite.test.decorators import *
-from lldbsuite.test.gdbclientutils import *
-from lldbsuite.test.lldbreverse import ReverseTestBase
-from lldbsuite.test import lldbutil
-
-
-class TestReverseContinueBreakpoints(ReverseTestBase):
-    NO_DEBUG_INFO_TESTCASE = True
-
-    def test_reverse_continue(self):
-        self.reverse_continue_internal(async_mode=False)
-
-    def test_reverse_continue_async(self):
-        self.reverse_continue_internal(async_mode=True)
-
-    def reverse_continue_internal(self, async_mode):
-        target, process, initial_threads = self.setup_recording(async_mode)
-
-        # Reverse-continue. We'll stop at the point where we started recording.
-        status = process.Continue(lldb.eRunReverse)
-        self.assertSuccess(status)
-        self.expect_async_state_changes(async_mode, process, [lldb.eStateRunning, lldb.eStateStopped])
-        self.expect(
-            "thread list",
-            STOPPED_DUE_TO_HISTORY_BOUNDARY,
-            substrs=["stopped", "stop reason = history boundary"],
-        )
-
-        # Continue forward normally until the target exits.
-        status = process.Continue()
-        self.expect_async_state_changes(async_mode, process, [lldb.eStateRunning, lldb.eStateExited])
-        self.assertSuccess(status)
-        self.assertState(process.GetState(), lldb.eStateExited)
-        self.assertEqual(process.GetExitStatus(), 0)
-
-    def test_reverse_continue_breakpoint(self):
-        self.reverse_continue_breakpoint_internal(async_mode=False)
-
-    def test_reverse_continue_breakpoint_async(self):
-        self.reverse_continue_breakpoint_internal(async_mode=True)
-
-    def reverse_continue_breakpoint_internal(self, async_mode):
-        target, process, initial_threads = self.setup_recording(async_mode)
-
-        # Reverse-continue to the function "trigger_breakpoint".
-        trigger_bkpt = target.BreakpointCreateByName("trigger_breakpoint", None)
-        status = process.Continue(lldb.eRunReverse)
-        self.assertSuccess(status)
-        self.expect_async_state_changes(async_mode, process, [lldb.eStateRunning, lldb.eStateStopped])
-        threads_now = lldbutil.get_threads_stopped_at_breakpoint(process, trigger_bkpt)
-        self.assertEqual(threads_now, initial_threads)
-
-    def test_reverse_continue_skip_breakpoint(self):
-        self.reverse_continue_skip_breakpoint_internal(async_mode=False)
-
-    def test_reverse_continue_skip_breakpoint_async(self):
-        self.reverse_continue_skip_breakpoint_internal(async_mode=True)
-
-    def reverse_continue_skip_breakpoint_internal(self, async_mode):
-        target, process, initial_threads = self.setup_recording(async_mode)
-
-        # Reverse-continue over a breakpoint at "trigger_breakpoint" whose
-        # condition is false.
-        # This tests that we continue in the correct direction after hitting
-        # the breakpoint.
-        trigger_bkpt = target.BreakpointCreateByName("trigger_breakpoint", None)
-        trigger_bkpt.SetCondition("false_condition")
-        status = process.Continue(lldb.eRunReverse)
-        self.expect_async_state_changes(async_mode, process, [lldb.eStateRunning, lldb.eStateStopped])
-        self.assertSuccess(status)
-        self.expect(
-            "thread list",
-            STOPPED_DUE_TO_HISTORY_BOUNDARY,
-            substrs=["stopped", "stop reason = history boundary"],
-        )
-
-    def setup_recording(self, async_mode):
-        """
-        Record execution of code between "start_recording" and "stop_recording" breakpoints.
-
-        Returns with the target stopped at "stop_recording", with recording disabled,
-        ready to reverse-execute.
-        """
-        self.build()
-        target = self.dbg.CreateTarget("")
-        process = self.connect(target)
-
-        # Record execution from the start of the function "start_recording"
-        # to the start of the function "stop_recording". We want to keep the
-        # interval that we record as small as possible to minimize the run-time
-        # of our single-stepping recorder.
-        start_recording_bkpt = target.BreakpointCreateByName("start_recording", None)
-        initial_threads = lldbutil.continue_to_breakpoint(process, start_recording_bkpt)
-        self.assertEqual(len(initial_threads), 1)
-        target.BreakpointDelete(start_recording_bkpt.GetID())
-        self.start_recording()
-        stop_recording_bkpt = target.BreakpointCreateByName("stop_recording", None)
-        lldbutil.continue_to_breakpoint(process, stop_recording_bkpt)
-        target.BreakpointDelete(stop_recording_bkpt.GetID())
-        self.stop_recording()
-
-        self.dbg.SetAsync(async_mode)
-        self.expect_async_state_changes(async_mode, process, [lldb.eStateStopped])
-
-        return target, process, initial_threads
-
-    def expect_async_state_changes(self, async_mode, process, states):
-        if not async_mode:
-            return
-        listener = self.dbg.GetListener()
-        lldbutil.expect_state_changes(self, listener, process, states)

diff  --git a/lldb/test/API/functionalities/reverse-execution/TestReverseContinueNotSupported.py b/lldb/test/API/functionalities/reverse-execution/TestReverseContinueNotSupported.py
deleted file mode 100644
index d610761b8cb0bc..00000000000000
--- a/lldb/test/API/functionalities/reverse-execution/TestReverseContinueNotSupported.py
+++ /dev/null
@@ -1,30 +0,0 @@
-import lldb
-import unittest
-from lldbsuite.test.lldbtest import *
-from lldbsuite.test.decorators import *
-from lldbsuite.test import lldbutil
-
-
-class TestReverseContinueNotSupported(TestBase):
-    NO_DEBUG_INFO_TESTCASE = True
-
-    def test_reverse_continue_not_supported(self):
-        self.build()
-        exe = self.getBuildArtifact("a.out")
-        target = self.dbg.CreateTarget(exe)
-        self.assertTrue(target, VALID_TARGET)
-
-        main_bkpt = target.BreakpointCreateByName("main", None)
-        self.assertTrue(main_bkpt, VALID_BREAKPOINT)
-
-        process = target.LaunchSimple(None, None, self.get_process_working_directory())
-        self.assertTrue(process, PROCESS_IS_VALID)
-
-        # This will fail gracefully.
-        status = process.Continue(lldb.eRunReverse)
-        self.assertFailure(status, "target does not support reverse-continue")
-
-        status = process.Continue()
-        self.assertSuccess(status)
-        self.assertState(process.GetState(), lldb.eStateExited)
-        self.assertEqual(process.GetExitStatus(), 0)

diff  --git a/lldb/test/API/functionalities/reverse-execution/main.c b/lldb/test/API/functionalities/reverse-execution/main.c
deleted file mode 100644
index 40e45dc9f5c317..00000000000000
--- a/lldb/test/API/functionalities/reverse-execution/main.c
+++ /dev/null
@@ -1,14 +0,0 @@
-volatile int false_condition = 0;
-
-static void start_recording() {}
-
-static void trigger_breakpoint() {}
-
-static void stop_recording() {}
-
-int main() {
-  start_recording();
-  trigger_breakpoint();
-  stop_recording();
-  return 0;
-}

diff  --git a/lldb/tools/lldb-dap/JSONUtils.cpp b/lldb/tools/lldb-dap/JSONUtils.cpp
index 211fd34957f496..558f889c4b7f23 100644
--- a/lldb/tools/lldb-dap/JSONUtils.cpp
+++ b/lldb/tools/lldb-dap/JSONUtils.cpp
@@ -1045,9 +1045,6 @@ llvm::json::Value CreateThreadStopped(lldb::SBThread &thread,
   case lldb::eStopReasonProcessorTrace:
     body.try_emplace("reason", "processor trace");
     break;
-  case lldb::eStopReasonHistoryBoundary:
-    body.try_emplace("reason", "history boundary");
-    break;
   case lldb::eStopReasonSignal:
   case lldb::eStopReasonException:
     body.try_emplace("reason", "exception");

diff  --git a/lldb/tools/lldb-dap/LLDBUtils.cpp b/lldb/tools/lldb-dap/LLDBUtils.cpp
index 1c5e3ac7008727..b38833c0fdb6b6 100644
--- a/lldb/tools/lldb-dap/LLDBUtils.cpp
+++ b/lldb/tools/lldb-dap/LLDBUtils.cpp
@@ -111,7 +111,6 @@ bool ThreadHasStopReason(lldb::SBThread &thread) {
   case lldb::eStopReasonVFork:
   case lldb::eStopReasonVForkDone:
   case lldb::eStopReasonInterrupt:
-  case lldb::eStopReasonHistoryBoundary:
     return true;
   case lldb::eStopReasonThreadExiting:
   case lldb::eStopReasonInvalid:


        


More information about the lldb-commits mailing list