[Lldb-commits] [lldb] [lldb] Implement basic support for reverse-continue (PR #99736)
Robert O'Callahan via lldb-commits
lldb-commits at lists.llvm.org
Sat Jul 20 06:00:04 PDT 2024
https://github.com/rocallahan updated https://github.com/llvm/llvm-project/pull/99736
>From 25e184d1f0d06c09726ef72c0b3f1966522ea3df Mon Sep 17 00:00:00 2001
From: Robert O'Callahan <robert at ocallahan.org>
Date: Fri, 19 Jul 2024 22:46:42 +1200
Subject: [PATCH] [lldb] Implement basic support for reverse-continue
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.
---
lldb/include/lldb/API/SBProcess.h | 2 +
lldb/include/lldb/Target/Process.h | 25 +-
lldb/include/lldb/Target/StopInfo.h | 3 +
lldb/include/lldb/lldb-enumerations.h | 6 +
.../Python/lldbsuite/test/gdbclientutils.py | 5 +-
.../Python/lldbsuite/test/lldbgdbproxy.py | 176 ++++++++
.../Python/lldbsuite/test/lldbreverse.py | 418 ++++++++++++++++++
.../Python/lldbsuite/test/lldbtest.py | 2 +
lldb/source/API/SBProcess.cpp | 20 +
lldb/source/API/SBThread.cpp | 2 +
.../source/Interpreter/CommandInterpreter.cpp | 3 +-
.../Process/Linux/NativeThreadLinux.cpp | 3 +
.../GDBRemoteCommunicationClient.cpp | 22 +
.../gdb-remote/GDBRemoteCommunicationClient.h | 6 +
.../GDBRemoteCommunicationServerLLGS.cpp | 1 +
.../Process/gdb-remote/ProcessGDBRemote.cpp | 94 ++++
.../Process/gdb-remote/ProcessGDBRemote.h | 2 +
lldb/source/Target/Process.cpp | 29 +-
lldb/source/Target/StopInfo.cpp | 29 ++
lldb/source/Target/Thread.cpp | 8 +-
.../reverse-execution/Makefile | 3 +
.../TestReverseContinueBreakpoints.py | 119 +++++
.../functionalities/reverse-execution/main.c | 14 +
lldb/tools/lldb-dap/JSONUtils.cpp | 3 +
lldb/tools/lldb-dap/LLDBUtils.cpp | 1 +
25 files changed, 979 insertions(+), 17 deletions(-)
create mode 100644 lldb/packages/Python/lldbsuite/test/lldbgdbproxy.py
create mode 100644 lldb/packages/Python/lldbsuite/test/lldbreverse.py
create mode 100644 lldb/test/API/functionalities/reverse-execution/Makefile
create mode 100644 lldb/test/API/functionalities/reverse-execution/TestReverseContinueBreakpoints.py
create mode 100644 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 778be79583990..9b17bac0093e6 100644
--- a/lldb/include/lldb/API/SBProcess.h
+++ b/lldb/include/lldb/API/SBProcess.h
@@ -160,6 +160,8 @@ class LLDB_API SBProcess {
lldb::SBError Continue();
+ lldb::SBError ReverseContinue();
+
lldb::SBError Stop();
lldb::SBError Kill();
diff --git a/lldb/include/lldb/Target/Process.h b/lldb/include/lldb/Target/Process.h
index c8475db8ae160..203d3484f3704 100644
--- a/lldb/include/lldb/Target/Process.h
+++ b/lldb/include/lldb/Target/Process.h
@@ -874,10 +874,10 @@ class Process : public std::enable_shared_from_this<Process>,
/// \see Thread:Resume()
/// \see Thread:Step()
/// \see Thread:Suspend()
- Status Resume();
+ Status Resume(lldb::RunDirection direction = lldb::eRunForward);
/// Resume a process, and wait for it to stop.
- Status ResumeSynchronous(Stream *stream);
+ Status ResumeSynchronous(Stream *stream, lldb::RunDirection direction = lldb::eRunForward);
/// Halts a running process.
///
@@ -1136,6 +1136,22 @@ class Process : public std::enable_shared_from_this<Process>,
return error;
}
+ /// Like DoResume() but executes in reverse if supported.
+ ///
+ /// \return
+ /// Returns \b true if the process successfully resumes using
+ /// the thread run control actions, \b false otherwise.
+ ///
+ /// \see Thread:Resume()
+ /// \see Thread:Step()
+ /// \see Thread:Suspend()
+ virtual Status DoResumeReverse() {
+ Status error;
+ error.SetErrorStringWithFormatv(
+ "error: {0} does not support reverse execution of processes", GetPluginName());
+ return error;
+ }
+
/// Called after resuming a process.
///
/// Allow Process plug-ins to execute some code after resuming a process.
@@ -2367,6 +2383,8 @@ 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();
}
@@ -2861,7 +2879,7 @@ void PruneThreadPlans();
///
/// \return
/// An Status object describing the success or failure of the resume.
- Status PrivateResume();
+ Status PrivateResume(lldb::RunDirection direction = lldb::eRunForward);
// Called internally
void CompleteAttach();
@@ -3139,6 +3157,7 @@ void PruneThreadPlans();
// m_currently_handling_do_on_removals are true,
// Resume will only request a resume, using this
// flag to check.
+ lldb::RunDirection m_last_run_direction;
/// This is set at the beginning of Process::Finalize() to stop functions
/// from looking up or creating things during or after a finalize call.
diff --git a/lldb/include/lldb/Target/StopInfo.h b/lldb/include/lldb/Target/StopInfo.h
index d1848fcbbbdb1..f49854275653e 100644
--- a/lldb/include/lldb/Target/StopInfo.h
+++ b/lldb/include/lldb/Target/StopInfo.h
@@ -138,6 +138,9 @@ class StopInfo : public std::enable_shared_from_this<StopInfo> {
static lldb::StopInfoSP
CreateStopReasonProcessorTrace(Thread &thread, const char *description);
+ 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 74ff458bf87de..5f1823ae04560 100644
--- a/lldb/include/lldb/lldb-enumerations.h
+++ b/lldb/include/lldb/lldb-enumerations.h
@@ -135,6 +135,9 @@ FLAGS_ENUM(LaunchFlags){
/// Thread Run Modes.
enum RunMode { eOnlyThisThread, eAllThreads, eOnlyDuringStepping };
+/// Execution directions
+enum RunDirection { eRunForward, eRunReverse };
+
/// Byte ordering definitions.
enum ByteOrder {
eByteOrderInvalid = 0,
@@ -253,6 +256,9 @@ enum StopReason {
eStopReasonFork,
eStopReasonVFork,
eStopReasonVForkDone,
+ // 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 1784487323ad6..732d617132068 100644
--- a/lldb/packages/Python/lldbsuite/test/gdbclientutils.py
+++ b/lldb/packages/Python/lldbsuite/test/gdbclientutils.py
@@ -510,8 +510,9 @@ def start(self):
self._thread.start()
def stop(self):
- self._thread.join()
- self._thread = None
+ if self._thread is not 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
new file mode 100644
index 0000000000000..45018e7daa7df
--- /dev/null
+++ b/lldb/packages/Python/lldbsuite/test/lldbgdbproxy.py
@@ -0,0 +1,176 @@
+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)
+
+ self.port = self.get_next_port()
+ 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
new file mode 100644
index 0000000000000..0f02fdffbdead
--- /dev/null
+++ b/lldb/packages/Python/lldbsuite/test/lldbreverse.py
@@ -0,0 +1,418 @@
+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 5e50b0c145885..166cc83c7093d 100644
--- a/lldb/packages/Python/lldbsuite/test/lldbtest.py
+++ b/lldb/packages/Python/lldbsuite/test/lldbtest.py
@@ -144,6 +144,8 @@
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 b88f897ff5280..5ad2ffae22df0 100644
--- a/lldb/source/API/SBProcess.cpp
+++ b/lldb/source/API/SBProcess.cpp
@@ -582,6 +582,26 @@ SBError SBProcess::Continue() {
return sb_error;
}
+SBError SBProcess::ReverseContinue() {
+ LLDB_INSTRUMENT_VA(this);
+
+ SBError sb_error;
+ ProcessSP process_sp(GetSP());
+
+ if (process_sp) {
+ std::lock_guard<std::recursive_mutex> guard(
+ process_sp->GetTarget().GetAPIMutex());
+
+ if (process_sp->GetTarget().GetDebugger().GetAsyncExecution())
+ sb_error.ref() = process_sp->Resume(RunDirection::eRunReverse);
+ else
+ sb_error.ref() = process_sp->ResumeSynchronous(nullptr, RunDirection::eRunReverse);
+ } else
+ sb_error.SetErrorString("SBProcess is invalid");
+
+ return sb_error;
+}
+
SBError SBProcess::Destroy() {
LLDB_INSTRUMENT_VA(this);
diff --git a/lldb/source/API/SBThread.cpp b/lldb/source/API/SBThread.cpp
index 53643362421d4..7ae1324e493d9 100644
--- a/lldb/source/API/SBThread.cpp
+++ b/lldb/source/API/SBThread.cpp
@@ -172,6 +172,7 @@ size_t SBThread::GetStopReasonDataCount() {
case eStopReasonInstrumentation:
case eStopReasonProcessorTrace:
case eStopReasonVForkDone:
+ case eStopReasonHistoryBoundary:
// There is no data for these stop reasons.
return 0;
@@ -230,6 +231,7 @@ 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 fc07168b6c0ac..a659f93d15bce 100644
--- a/lldb/source/Interpreter/CommandInterpreter.cpp
+++ b/lldb/source/Interpreter/CommandInterpreter.cpp
@@ -2513,7 +2513,8 @@ bool CommandInterpreter::DidProcessStopAbnormally() const {
const StopReason reason = stop_info->GetStopReason();
if (reason == eStopReasonException ||
reason == eStopReasonInstrumentation ||
- reason == eStopReasonProcessorTrace)
+ reason == eStopReasonProcessorTrace ||
+ reason == eStopReasonHistoryBoundary)
return true;
if (reason == eStopReasonSignal) {
diff --git a/lldb/source/Plugins/Process/Linux/NativeThreadLinux.cpp b/lldb/source/Plugins/Process/Linux/NativeThreadLinux.cpp
index 26cb26daabf52..1b23069a5530e 100644
--- a/lldb/source/Plugins/Process/Linux/NativeThreadLinux.cpp
+++ b/lldb/source/Plugins/Process/Linux/NativeThreadLinux.cpp
@@ -82,6 +82,9 @@ 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/gdb-remote/GDBRemoteCommunicationClient.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
index 74e392249a94e..c0c599161b992 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
@@ -197,6 +197,20 @@ 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;
@@ -293,6 +307,8 @@ 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;
@@ -346,6 +362,8 @@ 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
@@ -396,6 +414,10 @@ 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 898d176abc346..116b47c1edf03 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h
@@ -331,6 +331,10 @@ 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
@@ -561,6 +565,8 @@ 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 08d5f5039d516..9c7431028de1c 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp
@@ -714,6 +714,7 @@ static const char *GetStopReasonString(StopReason stop_reason) {
return "vfork";
case eStopReasonVForkDone:
return "vforkdone";
+ 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 604c92369e9a2..0df49ac6c1f33 100644
--- a/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
@@ -1395,6 +1395,94 @@ Status ProcessGDBRemote::DoResume() {
return error;
}
+Status ProcessGDBRemote::DoResumeReverse() {
+ Status error;
+ Log *log = GetLog(GDBRLog::Process);
+ LLDB_LOGF(log, "ProcessGDBRemote::DoResumeReverse()");
+
+ ListenerSP listener_sp(
+ Listener::MakeListener("gdb-remote.resume-packet-sent"));
+ if (listener_sp->StartListeningForEvents(
+ &m_gdb_comm, GDBRemoteClientBase::eBroadcastBitRunPacketSent)) {
+ listener_sp->StartListeningForEvents(
+ &m_async_broadcaster,
+ ProcessGDBRemote::eBroadcastBitAsyncThreadDidExit);
+
+ const size_t num_threads = GetThreadList().GetSize();
+
+ StreamString continue_packet;
+
+ // 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();
+ // We can only `bc` to reverse-continue all threads,
+ // or `bs` to reverse-step the current thread (which may also
+ // reverse-continue other threads by some amount).
+ // These packets do not support delivering signals.
+ if (num_continue_C_tids > 0 || num_continue_S_tids > 0) {
+ error.SetErrorString("can't deliver signals while running in reverse");
+ LLDB_LOGF(log, "ProcessGDBRemote::DoResumeReverse: Signals not supported");
+ return error;
+ }
+
+ if (num_continue_s_tids > 0) {
+ if (num_continue_s_tids > 1) {
+ error.SetErrorString("can't step multiple threads while reverse-stepping");
+ LLDB_LOGF(log, "ProcessGDBRemote::DoResumeReverse: can't step multiple threads");
+ return error;
+ }
+
+ if (!m_gdb_comm.GetReverseStepSupported()) {
+ error.SetErrorString("target does not support reverse-stepping");
+ LLDB_LOGF(log, "ProcessGDBRemote::DoResumeReverse: target does not support reverse-stepping");
+ return error;
+ }
+
+ m_gdb_comm.SetCurrentThreadForRun(m_continue_s_tids.front());
+ continue_packet.PutCString("bs");
+ } else {
+ if (!m_gdb_comm.GetReverseContinueSupported()) {
+ error.SetErrorString("target does not support reverse-continue");
+ LLDB_LOGF(log, "ProcessGDBRemote::DoResumeReverse: target does not support reverse-continue");
+ return error;
+ }
+
+ // All threads continue whether requested or not ---
+ // we can't change how threads ran in the past.
+ continue_packet.PutCString("bc");
+ }
+
+ EventSP event_sp;
+ if (!m_async_thread.IsJoinable()) {
+ error.SetErrorString("Trying to resume but the async thread is dead.");
+ LLDB_LOGF(log, "ProcessGDBRemote::DoResumeReverse: Trying to resume but the "
+ "async thread is dead.");
+ return error;
+ }
+
+ auto data_sp =
+ std::make_shared<EventDataBytes>(continue_packet.GetString());
+ m_async_broadcaster.BroadcastEvent(eBroadcastBitAsyncContinue, data_sp);
+
+ if (!listener_sp->GetEvent(event_sp, std::chrono::seconds(5))) {
+ error.SetErrorString("Resume timed out.");
+ LLDB_LOGF(log, "ProcessGDBRemote::DoResumeReverse: Resume timed out.");
+ } else if (event_sp->BroadcasterIs(&m_async_broadcaster)) {
+ error.SetErrorString("Broadcast continue, but the async thread was "
+ "killed before we got an ack back.");
+ LLDB_LOGF(log,
+ "ProcessGDBRemote::DoResumeReverse: Broadcast continue, but the "
+ "async thread was killed before we got an ack back.");
+ return error;
+ }
+ }
+
+ return error;
+}
+
void ProcessGDBRemote::ClearThreadIDList() {
std::lock_guard<std::recursive_mutex> guard(m_thread_list_real.GetMutex());
m_thread_ids.clear();
@@ -1851,6 +1939,10 @@ 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(
@@ -2275,6 +2367,8 @@ StateType ProcessGDBRemote::SetThreadStopInfo(StringExtractor &stop_packet) {
StreamString ostr;
ostr.Printf("%" PRIu64, wp_addr);
description = std::string(ostr.GetString());
+ } 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 b44ffefcd0d36..9b47010f2ece0 100644
--- a/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.h
+++ b/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.h
@@ -113,6 +113,8 @@ class ProcessGDBRemote : public Process,
Status DoResume() override;
+ Status DoResumeReverse() override;
+
Status DoHalt(bool &caused_stop) override;
Status DoDetach(bool keep_stopped) override;
diff --git a/lldb/source/Target/Process.cpp b/lldb/source/Target/Process.cpp
index d5a639d9beacd..63433a3471895 100644
--- a/lldb/source/Target/Process.cpp
+++ b/lldb/source/Target/Process.cpp
@@ -473,7 +473,8 @@ 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_finalizing(false), m_destructing(false),
+ m_resume_requested(false), m_last_run_direction(eRunForward),
+ 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),
m_can_interpret_function_calls(false), m_run_thread_plan_lock(),
@@ -870,6 +871,7 @@ bool Process::HandleProcessStateChangedEvent(
switch (thread_stop_reason) {
case eStopReasonInvalid:
case eStopReasonNone:
+ case eStopReasonHistoryBoundary:
break;
case eStopReasonSignal: {
@@ -1376,7 +1378,7 @@ void Process::SetPublicState(StateType new_state, bool restarted) {
}
}
-Status Process::Resume() {
+Status Process::Resume(RunDirection direction) {
Log *log(GetLog(LLDBLog::State | LLDBLog::Process));
LLDB_LOGF(log, "(plugin = %s) -- locking run lock", GetPluginName().data());
if (!m_public_run_lock.TrySetRunning()) {
@@ -1385,7 +1387,7 @@ Status Process::Resume() {
GetPluginName().data());
return error;
}
- Status error = PrivateResume();
+ Status error = PrivateResume(direction);
if (!error.Success()) {
// Undo running state change
m_public_run_lock.SetStopped();
@@ -1393,7 +1395,7 @@ Status Process::Resume() {
return error;
}
-Status Process::ResumeSynchronous(Stream *stream) {
+Status Process::ResumeSynchronous(Stream *stream, RunDirection direction) {
Log *log(GetLog(LLDBLog::State | LLDBLog::Process));
LLDB_LOGF(log, "Process::ResumeSynchronous -- locking run lock");
if (!m_public_run_lock.TrySetRunning()) {
@@ -1406,7 +1408,7 @@ Status Process::ResumeSynchronous(Stream *stream) {
Listener::MakeListener(ResumeSynchronousHijackListenerName.data()));
HijackProcessEvents(listener_sp);
- Status error = PrivateResume();
+ Status error = PrivateResume(direction);
if (error.Success()) {
StateType state =
WaitForProcessToStop(std::nullopt, nullptr, true, listener_sp, stream,
@@ -3252,7 +3254,7 @@ Status Process::ConnectRemote(llvm::StringRef remote_url) {
return error;
}
-Status Process::PrivateResume() {
+Status Process::PrivateResume(RunDirection direction) {
Log *log(GetLog(LLDBLog::Process | LLDBLog::Step));
LLDB_LOGF(log,
"Process::PrivateResume() m_stop_id = %u, public state: %s "
@@ -3264,6 +3266,11 @@ Status Process::PrivateResume() {
// filters before resuming.
UpdateAutomaticSignalFiltering();
+ if (m_last_run_direction != direction) {
+ 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()) {
@@ -3281,7 +3288,11 @@ Status Process::PrivateResume() {
"Process::PrivateResume PreResumeActions failed, not resuming.");
} else {
m_mod_id.BumpResumeID();
- error = DoResume();
+ if (direction == eRunForward) {
+ error = DoResume();
+ } else {
+ error = DoResumeReverse();
+ }
if (error.Success()) {
DidResume();
m_thread_list.DidResume();
@@ -3714,7 +3725,7 @@ bool Process::ShouldBroadcastEvent(Event *event_ptr) {
"from state: %s",
static_cast<void *>(event_ptr), StateAsCString(state));
ProcessEventData::SetRestartedInEvent(event_ptr, true);
- PrivateResume();
+ PrivateResume(m_last_run_direction);
}
} else {
return_value = true;
@@ -4316,7 +4327,7 @@ 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->PrivateResume(process_sp->m_last_run_direction);
} 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 95f78056b1644..aece2b99d7a02 100644
--- a/lldb/source/Target/StopInfo.cpp
+++ b/lldb/source/Target/StopInfo.cpp
@@ -1189,6 +1189,30 @@ 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 {
@@ -1411,6 +1435,11 @@ 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 e75f5a356cec2..3a1e950f65e55 100644
--- a/lldb/source/Target/Thread.cpp
+++ b/lldb/source/Target/Thread.cpp
@@ -618,10 +618,12 @@ void Thread::SetupForResume() {
// what the current plan is.
lldb::RegisterContextSP reg_ctx_sp(GetRegisterContext());
- if (reg_ctx_sp) {
+ ProcessSP process_sp(GetProcess());
+ if (reg_ctx_sp && process_sp &&
+ process_sp->GetLastRunDirection() == eRunForward) {
const addr_t thread_pc = reg_ctx_sp->GetPC();
BreakpointSiteSP bp_site_sp =
- GetProcess()->GetBreakpointSiteList().FindByAddress(thread_pc);
+ process_sp->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.
@@ -1715,6 +1717,8 @@ std::string Thread::StopReasonAsString(lldb::StopReason reason) {
return "instrumentation break";
case eStopReasonProcessorTrace:
return "processor trace";
+ 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
new file mode 100644
index 0000000000000..10495940055b6
--- /dev/null
+++ b/lldb/test/API/functionalities/reverse-execution/Makefile
@@ -0,0 +1,3 @@
+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
new file mode 100644
index 0000000000000..bd449e5652560
--- /dev/null
+++ b/lldb/test/API/functionalities/reverse-execution/TestReverseContinueBreakpoints.py
@@ -0,0 +1,119 @@
+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):
+ @add_test_categories(["dwarf"])
+ def test_reverse_continue(self):
+ self.reverse_continue_internal(async_mode=False)
+
+ @add_test_categories(["dwarf"])
+ 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.ReverseContinue()
+ 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)
+
+ @add_test_categories(["dwarf"])
+ def test_reverse_continue_breakpoint(self):
+ self.reverse_continue_breakpoint_internal(async_mode=False)
+
+ @add_test_categories(["dwarf"])
+ 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.ReverseContinue()
+ 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)
+
+ @add_test_categories(["dwarf"])
+ def test_reverse_continue_skip_breakpoint(self):
+ self.reverse_continue_skip_breakpoint_internal(async_mode=False)
+
+ @add_test_categories(["dwarf"])
+ 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.ReverseContinue()
+ 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/main.c b/lldb/test/API/functionalities/reverse-execution/main.c
new file mode 100644
index 0000000000000..40e45dc9f5c31
--- /dev/null
+++ b/lldb/test/API/functionalities/reverse-execution/main.c
@@ -0,0 +1,14 @@
+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 544e9ffb172bf..baf511edccecb 100644
--- a/lldb/tools/lldb-dap/JSONUtils.cpp
+++ b/lldb/tools/lldb-dap/JSONUtils.cpp
@@ -907,6 +907,9 @@ 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 a91cc6718f4df..2e2047745c131 100644
--- a/lldb/tools/lldb-dap/LLDBUtils.cpp
+++ b/lldb/tools/lldb-dap/LLDBUtils.cpp
@@ -110,6 +110,7 @@ bool ThreadHasStopReason(lldb::SBThread &thread) {
case lldb::eStopReasonFork:
case lldb::eStopReasonVFork:
case lldb::eStopReasonVForkDone:
+ case lldb::eStopReasonHistoryBoundary:
return true;
case lldb::eStopReasonThreadExiting:
case lldb::eStopReasonInvalid:
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