This is the mail archive of the
gdb-patches@sourceware.org
mailing list for the GDB project.
Re: [RFA] Emit a warning for ineffective set VAR = EXP command
On May 9, 2012, at 3:53 PM, <Paul_Koning@Dell.com> <Paul_Koning@Dell.com> wrote:
>
> 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?
Is it worth the burden ?
>
> 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);
>>
>