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Re: [RFA] Emit a warning for ineffective set VAR = EXP command
On May 9, 2012, at 8:28 AM, Tristan Gingold wrote:
>
> On May 7, 2012, at 9:38 PM, Joel Brobecker wrote:
>
>>>> This warns about "set variable $j++" presumably -- should the warning be
>>>> disabled for pre/post increments/decrements?
>>>
>>> I am not opposed to disable warnings for pre/post inc/dec.
>>> But this usage is dubious (the help explicitly mentions VAR=EXP !)
>>>
>>> Opinion ?
>>
>> I think we should avoid the warning for pre/post inc/dec. This
>> type of expression might be a little outside the method proposed
>> in our documentation, but I think it's still a perfectly valid
>> expression that results in an assignment being performed.
>
> I don't know who should approve this adjustment, but here is the version that deals with pre/post inc/dec.
> Note that it still warns for expressions such as i++ * 2.
If you had it walk through the elts[] list, would it then work for that case?
paul
>
> Tested on set-nowarns.exp.
>
> Tristan.
>
> 2012-05-09 Tristan Gingold <gingold@adacore.com>
>
> * printcmd.c (set_command): Add pre/post inc/dec.
>
> diff --git a/gdb/printcmd.c b/gdb/printcmd.c
> index 79e38f2..fa76296 100644
> --- a/gdb/printcmd.c
> +++ b/gdb/printcmd.c
> @@ -1080,11 +1080,21 @@ set_command (char *exp, int from_tty)
> struct cleanup *old_chain =
> make_cleanup (free_current_contents, &expr);
>
> - if (expr->nelts >= 1
> - && expr->elts[0].opcode != BINOP_ASSIGN
> - && expr->elts[0].opcode != BINOP_ASSIGN_MODIFY
> - && expr->elts[0].opcode != BINOP_COMMA)
> - warning (_("Expression is not an assignment (and might have no effect)"));
> + if (expr->nelts >= 1)
> + switch (expr->elts[0].opcode)
> + {
> + case UNOP_PREINCREMENT:
> + case UNOP_POSTINCREMENT:
> + case UNOP_PREDECREMENT:
> + case UNOP_POSTDECREMENT:
> + case BINOP_ASSIGN:
> + case BINOP_ASSIGN_MODIFY:
> + case BINOP_COMMA:
> + break;
> + default:
> + warning
> + (_("Expression is not an assignment (and might have no effect)"));
> + }
>
> evaluate_expression (expr);
> do_cleanups (old_chain);
>