Files
llvm-project/lldb/test/API/functionalities/scripted_process/dummy_scripted_process.py
Med Ismail Bennani 96c733e0db [lldb] Add support for PC-less scripted frames (#170805)
Scripted frames that materialize Python functions or other non-native
code are PC-less by design, meaning they don't have valid program
counter values. Previously, these frames would display invalid addresses
(`0xffffffffffffffff`) in backtrace output.

This patch updates `FormatEntity` to detect and suppress invalid address
display for PC-less frames, adds fallback to frame methods when symbol
context is unavailable, and modifies `StackFrame::GetSymbolContext` to
skip PC-based symbol resolution for invalid addresses.

The changes enable PC-less frames to display cleanly with proper
function names, file paths, and line numbers, and allow for source
display of foreign sources (like Python). Includes comprehensive test
coverage demonstrating frames pointing to Python source files.

Signed-off-by: Med Ismail Bennani <ismail@bennani.ma>
2025-12-05 23:57:54 +00:00

238 lines
6.8 KiB
Python

import os, struct, signal
from typing import Any, Dict
import lldb
from lldb.plugins.scripted_process import ScriptedProcess
from lldb.plugins.scripted_process import ScriptedThread
from lldb.plugins.scripted_process import ScriptedFrame
def my_python_function(x, y):
"""A sample Python function to demonstrate Python source display in scripted frames."""
result = x + y
if result > 100:
return result * 2
else:
return result
class DummyStopHook:
def __init__(self, target, args):
self.target = target
self.args = args
def handle_stop(self, exe_ctx, stream):
print("My DummyStopHook triggered. Printing args: \n%s" % self.args)
sp = exe_ctx.process.GetScriptedImplementation()
sp.handled_stop = True
class DummyScriptedProcess(ScriptedProcess):
memory = None
def __init__(self, exe_ctx: lldb.SBExecutionContext, args: lldb.SBStructuredData):
super().__init__(exe_ctx, args)
self.threads[0] = DummyScriptedThread(self, args)
self.memory = {}
addr = 0x500000000
debugger = self.target.GetDebugger()
index = debugger.GetIndexOfTarget(self.target)
self.memory[addr] = "Hello, target " + str(index)
self.handled_stop = False
def read_memory_at_address(
self, addr: int, size: int, error: lldb.SBError
) -> lldb.SBData:
data = lldb.SBData().CreateDataFromCString(
self.target.GetByteOrder(), self.target.GetCodeByteSize(), self.memory[addr]
)
return data
def write_memory_at_address(self, addr, data, error):
self.memory[addr] = data.GetString(error, 0)
return len(self.memory[addr]) + 1
def get_loaded_images(self):
return self.loaded_images
def get_process_id(self) -> int:
return 42
def should_stop(self) -> bool:
return True
def is_alive(self) -> bool:
return True
def get_scripted_thread_plugin(self):
return DummyScriptedThread.__module__ + "." + DummyScriptedThread.__name__
def my_super_secret_method(self):
if hasattr(self, "my_super_secret_member"):
return self.my_super_secret_member
else:
return None
class DummyScriptedThread(ScriptedThread):
def __init__(self, process, args):
super().__init__(process, args)
self.frames.append({"pc": 0x0100001B00})
self.frames.append(DummyScriptedFrame(self, args, len(self.frames), "baz123"))
self.frames.append(DummyScriptedFrame(self, args, len(self.frames), "bar"))
self.frames.append(DummyScriptedFrame(self, args, len(self.frames), "foo"))
cwd = os.path.dirname(os.path.abspath(__file__))
le = lldb.SBLineEntry()
le.SetFileSpec(lldb.SBFileSpec(os.path.join(cwd, "baz.cpp"), True))
le.SetLine(9)
le.SetColumn(10)
sym_ctx = lldb.SBSymbolContext()
sym_ctx.SetLineEntry(le)
self.frames.append(
DummyScriptedFrame(self, args, len(self.frames), "baz", sym_ctx)
)
# Add a frame with Python source
code = my_python_function.__code__
lineno = code.co_firstlineno
col_offset = getattr(
code, "co_firstcol_offset", 0
) # Python ≥3.11 has column info
py_le = lldb.SBLineEntry()
py_le.SetFileSpec(lldb.SBFileSpec(__file__, True))
py_le.SetLine(lineno) # Line where my_python_function is defined
py_le.SetColumn(col_offset)
py_sym_ctx = lldb.SBSymbolContext()
py_sym_ctx.SetLineEntry(py_le)
self.frames.append(
DummyScriptedFrame(
self, args, len(self.frames), "my_python_function", py_sym_ctx
)
)
def get_thread_id(self) -> int:
return 0x19
def get_name(self) -> str:
return DummyScriptedThread.__name__ + ".thread-1"
def get_state(self) -> int:
return lldb.eStateStopped
def get_stop_reason(self) -> Dict[str, Any]:
return {"type": lldb.eStopReasonTrace, "data": {}}
def get_register_context(self) -> str:
return struct.pack(
"21Q",
1,
2,
3,
4,
5,
6,
7,
8,
9,
10,
11,
12,
13,
14,
15,
16,
17,
18,
19,
20,
21,
)
class DummyScriptedFrame(ScriptedFrame):
def __init__(self, thread, args, id, name, sym_ctx=None):
super().__init__(thread, args)
self.id = id
self.name = name
self.sym_ctx = sym_ctx
def get_id(self):
return self.id
def get_function_name(self):
return self.name
def get_register_context(self) -> str:
return struct.pack(
"21Q",
0x10001,
0x10002,
0x10003,
0x10004,
0x10005,
0x10006,
0x10007,
0x10008,
0x10009,
0x100010,
0x100011,
0x100012,
0x100013,
0x100014,
0x100015,
0x100016,
0x100017,
0x100018,
0x100019,
0x100020,
0x100021,
)
def get_symbol_context(self):
def get_symbol_context_for_function(func_name):
module = self.target.FindModule(self.target.GetExecutable())
if not module.IsValid():
return None
sym_ctx_list = module.FindFunctions(func_name)
if not sym_ctx_list.IsValid() or sym_ctx_list.GetSize() == 0:
return None
return sym_ctx_list.GetContextAtIndex(0)
return (
self.sym_ctx if self.sym_ctx else get_symbol_context_for_function(self.name)
)
def get_scripted_frame_plugin(self):
return DummyScriptedFrame.__module__ + "." + DummyScriptedFrame.__name__
def __lldb_init_module(debugger, dict):
# This is used when loading the script in an interactive debug session to
# automatically, register the stop-hook and launch the scripted process.
if not "SKIP_SCRIPTED_PROCESS_LAUNCH" in os.environ:
debugger.HandleCommand(
"target stop-hook add -k first -v 1 -k second -v 2 -P %s.%s"
% (__name__, DummyStopHook.__name__)
)
debugger.HandleCommand(
"process launch -C %s.%s" % (__name__, DummyScriptedProcess.__name__)
)
else:
print(
"Name of the class that will manage the scripted process: '%s.%s'"
% (__name__, DummyScriptedProcess.__name__)
)
print(
"Name of the class that will manage the stop-hook: '%s.%s'"
% (__name__, DummyStopHook.__name__)
)