[lldb-dev] Question about remote debugging protocol setup

[jingham at apple.com]

Note, if you are going to write an monitor to work with lldb, if you haven't already, take a look at:

http://llvm.org/svn/llvm-project/lldb/trunk/docs/lldb-gdb-remote.txt

That has the additional packets that lldb will send an use to make debugging go faster.  lldb will still work with a vanilla gdb-remote protocol monitor, but have a look at what is there to see if it makes sense for you to support any of these additions.

Jim

On Apr 11, 2014, at 2:01 AM, Matthew Gardiner <mg11 at csr.com> wrote:

> Hi All,
> 
> I'm trying to understand how to write a gdbserver for one of our chips, which we are planning to attach lldb to.
> 
> First off, I started doing a sniff of protocol between debugger and gdbserver with local debug of an linux intel 64-bit process.
> 
> I then compared the traces between the debugger being gdb and lldb.
> 
> Using gdb:
> 
> CLIENT SENDS: +
> CLIENT SENDS: $qSupported:multiprocess+;xmlRegisters=i386;qRelocInsn+#b5
> SERVER SENDS: +
> SERVER SENDS: $PacketSize=3fff;QPassSignals+;QProgramSignals+;qXfer:libraries-svr4:read+;augmented-libraries-svr4-read+;qXfer:auxv:read+;qXfer:spu:read+;qXfer:spu:write+;qXfer:siginfo:read+;qXfer:siginfo:write+;qXfer:features:read+;QStartNoAckMode+;qXfer:osdata:read+;multiprocess+;QNonStop+;QDisableRandomization+;qXfer:threads:read+;ConditionalTracepoints+;TraceStateVariables+;TracepointSource+;DisconnectedTracing+;FastTracepoints+;StaticTracepoints+;InstallInTrace+;qXfer:statictrace:read+;qXfer:traceframe-info:read+;EnableDisableTracepoints+;QTBuffer:size+;tracenz+;ConditionalBreakpoints+;BreakpointCommands+;QAgent+;Qbtrace:bts+;Qbtrace:off+;qXfer:btrace:read+#ad
> SERVER SENDS: +
> CLIENT SENDS: $QStartNoAckMode#b0
> SERVER SENDS: +
> SERVER SENDS: $OK#9a
> CLIENT SENDS: +
> 
> Using lldb:
> 
> CLIENT SENDS: +
> CLIENT SENDS: $QStartNoAckMode#b0
> SERVER SENDS: +
> CLIENT SENDS: $OK#9a
> SERVER SENDS: +
> 
> So I'm wondering why does lldb not send the qSupported request? Is it a deliberate omission or is this still a work in progress?
> 
> All viewpoints appreciated,
> thanks Matt
> 
> 
> 
> 
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