[lldb-dev] No stopping event during launch(stop_at_entry=True) on Linux?

Jeffrey.fudan via lldb-dev lldb-dev at lists.llvm.org
Tue Feb 23 23:36:57 PST 2016


Makes sense, will file a bug for it.

Sent from my iPad

> On Feb 23, 2016, at 5:10 PM, Jim Ingham <jingham at apple.com> wrote:
> 
> That also is a bug.  If it is going to do a public stop, it has to send a stop event.
> 
> Jim
> 
>> On Feb 23, 2016, at 2:52 PM, Jeffrey Tan <jeffrey.fudan at gmail.com> wrote:
>> 
>> I am not sure. From the output, it seems lldb does stop at the entry point(because you can issue "bt" command to dump the stack) in both platforms; the problem seems to be that it did not emit the stopped event for its stop on linux.  
>> 
>> On Tue, Feb 23, 2016 at 2:03 PM, Jim Ingham <jingham at apple.com> wrote:
>> If the linux side is not obeying "stop_at_entry" then that is a bug.
>> 
>> Jim
>> 
>> 
>>> On Feb 23, 2016, at 1:49 PM, Jeffrey Tan via lldb-dev <lldb-dev at lists.llvm.org> wrote:
>>> 
>>> Hi,
>>> 
>>> I have got lldb launch working fine on my macbook for sometime. But when I try the same code on Linux, it failed to emit any stopping events during initial launch.
>>> 
>>> When I run the reproduce code(listed at the end), I got the following different results:
>>> 
>>> The key difference is that Macbook will emit a stopped event which caused our IDE UI to enter break mode, while Linux violates this assumption. Is this a bug?
>>> 
>>> ======================Mac======================
>>> lldb_pythonpath: /Applications/Xcode.app/Contents/Developer/../SharedFrameworks/LLDB.framework/Resources/Python
>>> Launch result: success
>>> <Listener> Listening Thread ID: 4610625536
>>> dbg> Target event: ModulesLoaded
>>> Process event: StateChanged, Stopped
>>> Stop reason: 5
>>> dbg> bt
>>> * thread #1: tid = 0x101f01d, 0x00007fff6401a000 dyld`_dyld_start, stop reason = signal SIGSTOP
>>>  * frame #0: 0x00007fff6401a000 dyld`_dyld_start
>>> ======================Mac======================
>>> 
>>> ======================Linux======================
>>> python linux_launch.py
>>> find_lldb: <module 'lldb' from '/home/jeffreytan/project/llvm-bin/Debug+Asserts/lib/python2.7/site-packages/lldb/__init__.pyc'>
>>> Launch result: success
>>> <Listener> Listening Thread ID: 140316621375232
>>> dbg> bt
>>> * thread #1: tid = 2794520, 0x00007f6165b7bb00, name = 'foo', stop reason = signal SIGSTOP
>>>  * frame #0: 0x00007f6165b7bb00
>>> ======================Linux======================
>>> 
>>> ============================Repro main.py============================
>>> # Should be first for LLDB package to be added to search path.
>>> from find_lldb import lldb
>>> import sys
>>> import os
>>> import time
>>> from sys import stdin, stdout
>>> from event_thread import LLDBListenerThread
>>> import threading
>>> 
>>> 
>>> def interctive_loop(debugger):
>>>    while (True):
>>>        stdout.write('dbg> ')
>>>        command = stdin.readline().rstrip()
>>>        if len(command) == 0:
>>>            continue
>>>        if command == 'q':
>>>            return
>>>        debugger.HandleCommand(command)
>>> 
>>> def do_test():
>>>    debugger = lldb.SBDebugger.Create()
>>>    debugger.SetAsync(True)
>>>    executable_path = '~/Personal/compiler/CompilerConstruction/code/compiler'
>>>    target = debugger.CreateTargetWithFileAndArch(executable_path, lldb.LLDB_ARCH_DEFAULT)
>>> 
>>>    listener = lldb.SBListener('Event Listener')
>>>    error = lldb.SBError()
>>>    process = target.Launch (listener,
>>>                             None,      # argv
>>>                             None,      # envp
>>>                             None,      # stdin_path
>>>                             None,      # stdout_path
>>>                             None,      # stderr_path
>>>                             None,      # working directory
>>>                             0,         # launch flags
>>>                             True,     # Stop at entry
>>>                             error)     # error
>>>    print 'Launch result: %s' % str(error)
>>> 
>>>    running_signal = threading.Event()
>>>    stopped_signal = threading.Event()
>>>    event_thread = LLDBListenerThread(debugger, running_signal, stopped_signal)
>>>    event_thread.start()
>>> 
>>>    interctive_loop(debugger)
>>> 
>>>    event_thread.should_quit = True
>>>    event_thread.join()
>>> 
>>>    lldb.SBDebugger.Destroy(debugger)
>>>    return debugger
>>> 
>>> def main():
>>>    debugger = do_test()
>>> 
>>> if __name__ == '__main__':
>>>    main()
>>> 
>>> ============================Event_thread============================
>>> class LLDBListenerThread(Thread):
>>>    should_quit = False
>>> 
>>>    def __init__(self, debugger, running_signal=None, stopped_sigal=None):
>>>      Thread.__init__(self)
>>>      self._running_signal = running_signal
>>>      self._stopped_sigal = stopped_sigal
>>>      process = debugger.GetSelectedTarget().process
>>>      self.listener = debugger.GetListener()
>>>      self._add_listener_to_process(process)
>>>      self._add_listener_to_target(process.target)
>>> 
>>> 
>>>    def _add_listener_to_target(self, target):
>>>        # Listen for breakpoint/watchpoint events (Added/Removed/Disabled/etc).
>>>        broadcaster = target.GetBroadcaster()
>>>        mask = lldb.SBTarget.eBroadcastBitBreakpointChanged | lldb.SBTarget.eBroadcastBitWatchpointChanged | lldb.SBTarget.eBroadcastBitModulesLoaded
>>>        broadcaster.AddListener(self.listener, mask)
>>> 
>>>    def _add_listener_to_process(self, process):
>>>        # Listen for process events (Start/Stop/Interrupt/etc).
>>>        broadcaster = process.GetBroadcaster()
>>>        mask = lldb.SBProcess.eBroadcastBitStateChanged | lldb.SBProcess.eBroadcastBitSTDOUT | lldb.SBProcess.eBroadcastBitSTDERR | lldb.SBProcess.eBroadcastBitInterrupt
>>>        broadcaster.AddListener(self.listener, mask)
>>> 
>>>    def run(self):
>>>        print '<Listener> Listening Thread ID: %d' % thread.get_ident()
>>>        while not self.should_quit:
>>>            event = lldb.SBEvent()
>>>            if self.listener.WaitForEvent(1, event):
>>>                if lldb.SBTarget.EventIsTargetEvent(event):
>>>                    self._handle_target_event(event)
>>>                elif lldb.SBProcess.EventIsProcessEvent(event):
>>>                    self._handle_process_event(event)
>>>                elif lldb.SBBreakpoint.EventIsBreakpointEvent(event):
>>>                    self._handle_breakpoint_event(event)
>>>                elif lldb.SBThread.EventIsThreadEvent(event):
>>>                    self._handle_thread_event(event)
>>>                else:
>>>                    self._handle_unknown_event(event)
>>>        print '<Listener> Exiting listener thread'
>>> 
>>>    def _handle_target_event(self, event):
>>>        event_type = event.GetType()
>>>        print 'Target event: %s' % target_event_type_to_name_map[event_type]
>>> 
>>>    def _handle_process_event(self, event):
>>>        if lldb.SBProcess.GetRestartedFromEvent(event):
>>>            print 'Non stopping event: %s' % str(event)
>>>            return
>>>        process = lldb.SBProcess.GetProcessFromEvent(event)
>>>        event_type = event.GetType()
>>>        print 'Process event: %s, %s' % (process_event_type_to_name_map[event_type], process_state_name_map[process.state])
>>>        if process.state == lldb.eStateExited:
>>>            self.should_quit = True
>>>        elif process.state == lldb.eStateStopped:
>>>            if self._stopped_sigal:
>>>                self._stopped_sigal.set()
>>>        else:
>>>            if self._running_signal:
>>>                self._running_signal.set()
>>> 
>>>        thread = process.selected_thread
>>>        print 'Stop reason: %d' % thread.GetStopReason()
>>>        if event_type == lldb.SBProcess.eBroadcastBitSTDOUT:
>>>            print 'Stdout:'
>>>            while True:
>>>                output = process.GetSTDOUT(1024)
>>>                if len(output) == 0:
>>>                    break
>>>                stdout.write(output)
>>> 
>>>    def _handle_breakpoint_event(self, event):
>>>        breakpoint = lldb.SBBreakpoint.GetBreakpointFromEvent(event)
>>>        event_type = lldb.SBBreakpoint.GetBreakpointEventTypeFromEvent(event)
>>>        print 'Breakpoint event: [%s] %s' % (breakpoint_event_type_to_name_map[event_type], str(breakpoint))
>>> 
>>>    def _handle_unknown_event(self, event):
>>>        print 'Unknown event'
>>> 
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> 


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