What about add new commands "maintenance agent-breakpoint id expression" and "maintenance agent-eval-breakpoint id expression"

Hui Zhu teawater@gmail.com
Tue Jun 12 11:42:00 GMT 2012

On Tue, Jun 12, 2012 at 10:02 AM, Yao Qi <yao@codesourcery.com> wrote:
> On 06/12/2012 08:15 AM, Hui Zhu wrote:
>> Hi guys,
>> The "maintenance agent" and "maintenance agent-eval" are for translate
>> an expression into remote agent bytecode.
>> Both of them got address info from frame.  But when we use tracepoint or
>> breakpoint with agent code, this address is from tracepoint or breakpoint.
> Agent expression evaluation makes sense in the context of "current
> scope" or "current frame".  We can't switch to a frame at any arbitrary
> address, because the frame maybe does not exist.

What your worry about is line "expr = parse_expression (exp);" cannot
work, right?
It can be change to function "parse_exp_1" to handle this issue.

BTW if agent generate need current scope or current frame, how this
code generate when breakpoint or tracepoint use it? :)

> Any examples that "maint agent" doesn't meet your needs in
> breakpoint/tracepoint?  It works in the following simple case,
> (gdb) b main if (unsigned int) main > 1
> (gdb) maintenance agent-eval (unsigned int) main > 1
>  0  const64 134513662
>  9  zero_ext 32
>  11  const8 1
>  13  zero_ext 32
>  15  swap
>  16  less_unsigned
>  17  end
> --
> Yao (齐尧)

It have too much limit.  For example, it will not work when we want
collect an local var inside of a function.


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