[lldb-dev] Launching the program through 'gdb-remote' process plugin
chansarav
chansarav at gmail.com
Wed Aug 21 22:14:14 PDT 2013
Thanks for the reply.
I enabled the packet logging in LLDB.
(lldb) log enable gdb-remote packets
(lldb) process connect --plugin gdb-remote connect://localhost:51000
< 1> send packet: +
history[1] tid=0xb1d819d0 < 1> send packet: +
< 26> send packet: $QThreadSuffixSupported#e4
< 1> read packet: +
< 4> read packet: $#00
< 1> send packet: +
< 27> send packet: $QListThreadsInStopReply#21
< 1> read packet: +
< 7> read packet: $E01#a6
< 1> send packet: +
< 10> send packet: $vCont?#49
< 1> read packet: +
< 15> read packet: $vCont[;c;s]#0e
< 1> send packet: +
< 27> send packet: $qVAttachOrWaitSupported#38
< 1> read packet: +
< 6> send packet: $qC#b4
< 1> read packet: +
< 7> read packet: $QC0#c4
< 1> send packet: +
(lldb) run
After this lldb just hangs. lldb doesn't send any packet after the 'run'
command. I debugged by inserting a breakpoint in lldb's code which sends
the 'A' packet. And that breakpoint was not hit.
On Wed, Aug 21, 2013 at 10:31 PM, Greg Clayton <gclayton at apple.com> wrote:
> The "process launch" command should send the 'A' packet, and it is waiting
> for a stop reply response from the 'A' packet. Try enabling the packet
> logging in LLDB:
>
> (lldb) log enable gdb-remote packets
> (lldb) process connect ...
> (lldb) run
>
> My guess is that the 'A' packet isn't responding with a stop reply packet.
>
> On Aug 21, 2013, at 7:47 AM, chansarav <chansarav at gmail.com> wrote:
>
> > Hi,
> >
> > I am connecting lldb with my simulator through 'gdb-remote' process
> plugin. After extablishing the connection, I want to issue the 'process
> launch' command in lldb which should send the arguments packet 'A' to
> simulator asking it to launch the program.
> >
> > I am facing the problem while issuing the 'process launch' command in
> lldb. When I give the 'process launch' command, lldb hangs and there is no
> communication with simulator. When I debugged with gdb, I got the backtrace
> as follows:
> >
> > #2 0xb6703a6f in lldb_private::Condition::Wait (this=0x8077dac,
> mutex=..., abstime=0x0, timed_out=0xbfffaa9f) at
> /home/chandra/llvm-3.1/tools/lldb/source/Host/common/Condition.cpp:92
> > #3 0xb662768d in lldb_private::Predicate<bool>::WaitForValueEqualTo
> (this=0x8077d90, value=true, abstime=0x0, timed_out=0xbfffaa9f) at
> /home/chandra/llvm-3.1/tools/lldb/source/Core/../../include/lldb/Host/Predicate.h:317
> > #4 0xb662b03f in lldb_private::Listener::WaitForEventsInternal
> (this=0x8077d3c, timeout=0x0, broadcaster=0xadb0179c,
> broadcaster_names=0x0, num_broadcaster_names=0, event_type_mask=3,
> event_sp=...) at
> /home/chandra/llvm-3.1/tools/lldb/source/Core/Listener.cpp:409
> > #5 0xb662b1f7 in
> lldb_private::Listener::WaitForEventForBroadcasterWithType (this=0x8077d3c,
> timeout=0x0, broadcaster=0xadb0179c, event_type_mask=3, event_sp=...) at
> /home/chandra/llvm-3.1/tools/lldb/source/Core/Listener.cpp:440
> > #6 0xb69421ec in lldb_private::Process::WaitForStateChangedEvents
> (this=0xadb01788, timeout=0x0, event_sp=...) at
> /home/chandra/llvm-3.1/tools/lldb/source/Target/Process.cpp:1069
> > #7 0xb6941f2c in lldb_private::Process::WaitForProcessToStop
> (this=0xadb01788, timeout=0x0) at
> /home/chandra/llvm-3.1/tools/lldb/source/Target/Process.cpp:977
> > #8 0xb6587d98 in CommandObjectProcessLaunch::DoExecute (this=0x80813d0,
> launch_args=..., result=...) at
> /home/chandra/llvm-3.1/tools/lldb/source/Commands/CommandObjectProcess.cpp:220
> > #9 0xb672c999 in lldb_private::CommandObjectParsed::Execute
> (this=0x80813d0, args_string=0xb4d667bc "", result=...) at
> /home/chandra/llvm-3.1/tools/lldb/source/Interpreter/CommandObject.cpp:856
> > #10 0xb67215d3 in lldb_private::CommandInterpreter::HandleCommand
> (this=0x8077fc8, command_line=0x883a614 "process launch",
> lazy_add_to_history=lldb_private::eLazyBoolYes, result=...,
> > override_context=0x0, repeat_on_empty_command=true,
> no_context_switching=false) at
> /home/chandra/llvm-3.1/tools/lldb/source/Interpreter/CommandInterpreter.cpp:1571
> > #11 0xb64e0ced in lldb::SBCommandInterpreter::HandleCommand
> (this=0xbfffc2cc, command_line=0x883a614 "process launch", result=...,
> add_to_history=true) at
> /home/chandra/llvm-3.1/tools/lldb/source/API/SBCommandInterpreter.cpp:97
> > #12 0x0805a103 in Driver::HandleIOEvent (this=0xbfffec7c, event=...) at
> /home/chandra/llvm-3.1/tools/lldb/tools/driver/Driver.cpp:996
> > #13 0x0805b516 in Driver::MainLoop (this=0xbfffec7c) at
> /home/chandra/llvm-3.1/tools/lldb/tools/driver/Driver.cpp:1430
> > #14 0x0805bbf2 in main (argc=4, argv=0xbfffede4, envp=0xbfffedf8) at
> /home/chandra/llvm-3.1/tools/lldb/tools/driver/Driver.cpp:1562
> >
> > Though I am analyzing on this, Can someone help me in finding out what
> goes wrong while trying to launch a program in simulator through
> 'gdb-remote' process plugin?
> >
> >
> > Following is the communication between lldb and simulator for the
> "process connect --plugin gdb-remote connect://localhost:51000" command.
> >
> > Send Packet: QStartNoAckMode: 15 chars
> > Read Packet:
> > Send Packet: QThreadSuffixSupported: 22 chars
> > Read Packet:
> > Send Packet: QListThreadsInStopReply: 23 chars
> > Read Packet: E01
> > Send Packet: qHostInfo: 9 chars
> > Read Packet:
> cputype:201;cpusubtype:-2;ostype:unknown;vendor:unknown;endian:little;ptrsize:4;
> > Send Packet: vCont?: 6 chars
> > Read Packet: vCont[;c;s]
> > Send Packet: qVAttachOrWaitSupported: 23 chars
> > Read Packet:
> > Send Packet: qC: 2 chars
> > Read Packet: QC0
> >
> > LLDB sets the status as connected after this communication.
> > (snip start)
> > if (pid == LLDB_INVALID_PROCESS_ID)
> > {
> > // We don't have a valid process ID, so note that we are
> connected
> > // and could now request to launch or attach, or get remote
> process
> > // listings...
> > SetPrivateState (eStateConnected);
> > }
> > (snip end)
> > function: ProcessGDBRemote::DoConnectRemote ()
> >
> > Thanks,
> > Chandra Kumar R.
> > _______________________________________________
> > lldb-dev mailing list
> > lldb-dev at cs.uiuc.edu
> > http://lists.cs.uiuc.edu/mailman/listinfo/lldb-dev
>
>
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