Re: Reset breakpoint after load?

[Jie Zhang <jie.zhang@analog.com>]

On 01/22/2010 02:29 AM, Michael Snyder wrote:
> Dave Korn wrote:
>> On 19/01/2010 07:36, Jie Zhang wrote:
>>
>>> gdb-comm.exp sets breakpoints on exit and abort before load. The problem
>>> is that GDB tries to skip prologue according to what it reads from
>>> memory, which might contain random data since the executable has not
>>> been loaded into memory. In my case, sometimes skip_prologue might skip
>>> one or two more instructions, which happens to be an exception
>>> instruction and will trap the processor into an exception event loop
>>> after running the executable before hit the breakpoints.
>>
>> Something is wrong here. Before the inferior is started, gdb should be
>> looking at the prologue bytes from the executable image file, not the
>> inferior
>> memory. Is something going wrong in gdb_comm_file_cmd()?
>
> Dave, Jie,
>
> I don't believe that gdb can tell when the (remote) inferior
> is started. All gdb knows is that target remote is started.
> Thus, if we connect to target remote and then load the image,
> there is an interval during which gdb will attempt to read
> the prologue bytes from un-initialized target memory.
>
> Seems to me, that interval is a bad time to set breakpoints.
>
I agree that that interval is a bad time to set breakpoints. But if GDB 
re-set breakpoints after load, it still can get the breakpoint set at 
the right addresses.


Jie