================
@@ -0,0 +1,528 @@
+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).
+ """
+
+ NO_DEBUG_INFO_TESTCASE = True
+
+ """
+ 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
+
+ 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", ":"):
+ # Disable multiprocess support in the server and in LLDB
+ # since Mac debugserver doesn't support it and we want lldb-server
to
+ # be consistent with that
+ reply = self.pass_through(packet.replace(";multiprocess", ""))
+ return reply.replace(";multiprocess", "") +
";ReverseStep+;ReverseContinue+"
+ if packet == "c" or packet == "s":
+ packet = "vCont;" + packet
+ elif (
+ packet[0] == "c" or packet[0] == "s" or packet[0] == "C" or
packet[0] == "S"
+ ):
+ raise ValueError(
+ "Old-style continuation packets with address or signal not
supported yet"
+ )
+ if self.is_command(packet, "vCont", ";"):
+ if self.recording_enabled:
+ return self.continue_with_recording(packet)
+ snapshots = []
+ 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 self.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(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 == "metype":
+ reason = self.stop_reason_from_mach_exception(stop_pairs)
+ if reason == "breakpoint":
+ is_swbreak = True
+ elif reason != "singlestep":
+ raise ValueError(f"Unsupported stop reason in {reply}")
+ continue
+ if key in [
+ "name",
+ "threads",
+ "thread-pcs",
+ "reason",
+ "mecount",
+ "medata",
+ "memory",
+ ]:
+ 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 stop_reason_from_mach_exception(self, stop_pairs):
+ # See StopInfoMachException::CreateStopReasonWithMachException.
+ if int(stop_pairs["metype"]) != 6: # EXC_BREAKPOINT
+ raise ValueError(f"Unsupported exception type {value} in {reply}")
+ medata = stop_pairs["medata"]
+ arch = self.getArchitecture()
+ if arch in ["amd64", "i386", "x86_64"]:
+ if int(medata[0], 16) == 2:
+ return "breakpoint"
+ if int(medata[0], 16) == 1 and int(medata[1], 16) == 0:
+ return "singlestep"
+ elif arch in ["arm64", "arm64e"]:
+ if int(medata[0], 16) == 1 and int(medata[1], 16) != 0:
+ return "breakpoint"
+ elif int(medata[0], 16) == 1 and int(medata[1], 16) == 0:
+ return "singlestep"
+ else:
+ raise ValueError(f"Unsupported architecture '{arch}'")
+ raise ValueError(f"Unsupported exception details in {reply}")
+
+ def parse_stop_reply(self, reply):
+ if not reply:
+ raise ValueError("Invalid empty packet")
+ if reply[0] == "T" and len(reply) >= 3:
+ result = {}
+ for k, v in self.parse_pairs(reply[3:]):
+ if k in ["medata", "memory"]:
+ if k in result:
+ result[k].append(v)
+ else:
+ result[k] = [v]
+ else:
+ result[k] = v
+ return (int(reply[1:3], 16), result)
+ raise ValueError("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
+ )
+
+ # The memory above or below the stack pointer may be mapped, but
not
----------------
DavidSpickett wrote:
If I was thinking straight, I'd have made the changes their own commit, but too
late for that now.
This is part of them.
https://github.com/llvm/llvm-project/pull/123945
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