Re: [PATCH] fix Bug 15180 Agent style dprintf does not respect conditions

[Yao Qi <yao@codesourcery.com>]

On 04/23/2013 03:14 PM, Hui Zhu wrote:
> +  condition_true = gdb_breakpoint_here (event_child->stop_pc)
> +		   && gdb_condition_true_at_breakpoint (event_child->stop_pc);
> +
>     /* If GDB wanted this thread to single step, we always want to
>        report the SIGTRAP, and let GDB handle it.  Watchpoints should
>        always be reported.  So should signals we can't explain.  A
> @@ -2628,11 +2632,11 @@ Check if we're already there.\n",
>   		   || event_child->stopped_by_watchpoint
>   		   || (!step_over_finished
>   		       && !bp_explains_trap && !trace_event)
> -		   || (gdb_breakpoint_here (event_child->stop_pc)
> -		       && gdb_condition_true_at_breakpoint (event_child->stop_pc)
> +		   || (condition_true
>   		       && gdb_no_commands_at_breakpoint (event_child->stop_pc)));
>
> -  run_breakpoint_commands (event_child->stop_pc);
> +  if (condition_true)
> +    run_breakpoint_commands (event_child->stop_pc);

Hui,
This patch works when there is only one dprintf set on a certain 
address.  However, supposing we set two dprintf breakpoints on the same 
address, one condition is true and the other is false, commands of both 
breakpoint will be executed, which is wrong.  See the session below:

$ ./gdb ./testsuite/gdb.base/dprintf
(gdb) target  remote :1234
(gdb) set breakpoint condition-evaluation target
// ensure that condition is evaluated in the target side.
(gdb) set dprintf-style agent
(gdb) dprintf foo , "true\n"
(gdb) condition 1 main > 1
(gdb) dprintf foo, "false\n"
(gdb) condition 2 main == 0
(gdb) info breakpoints
Num     Type           Disp Enb Address    What
1       dprintf        keep y   0x080484aa in foo at 
../../../../git/gdb/testsuite/gdb.base/dprintf.c:25
         stop only if main > 1 (host evals)
                                ^^^^^^^^^^
// it should be "(target evals)", caused by a separated bug.
         agent-printf "true\n"
2       dprintf        keep y   0x080484aa in foo at 
../../../../git/gdb/testsuite/gdb.base/dprintf.c:25
         stop only if main == 0 (host evals)
         agent-printf "false\n"
(gdb) c
Continuing.
[Inferior 1 (process 4135) exited with code 0152]

In the other console, we can see the output:

kickoff 1234
also to stderr 1234
false
true
false
false
true
false
false
true
false

Child exited with status 106

AFAICS, it is not a bug specific to dprintf, all target-side commands 
are affected by this bug, because the command is not well grouped or 
associated with condition in target side.

-- 
Yao (齐尧)