[2/2] Don't lose language determined from the "main" name (fix gdb.ada/minsyms.exp)

  On 11/21/2017 04:42 PM, Pedro Alves wrote:
> On 11/21/2017 04:23 PM, Sergio Durigan Junior wrote:

>> Since this is guaranteed to be an stap probe, WDYT about moving this
>> scoped_restore_current_language to
>> stap-probe.c:stap_evaluate_probe_argument?  This way we won't be bit by
>> this problem in other parts that also evaluate arguments of probes.
>>
>> Arguably, this should be set for every probe type IMHO, but it's fine if
>> we just do it for stap probes for now.
> 
> That sounds like a good idea.  But we could do it in 
> evaluate_probe_argument then, which handles all probe types?
> 
> [In your probe C++ification, that translates to evaluate_probe_argument
> becoming a  non-virtual method of probe, which then calls into a
> protected virtual method that is overridden by the actual probe
> implementation (see e.g., the do_xxx methods of class ui_out).]

Hmm, maybe what we need instead is to make expression evaluation
never set the selected frame (and thus language as side effect)
if it wasn't selected/set already.  Like below.  This fixes
the testcase too.  I'll run the full testsuite now.  WDYT?

From c5fd954787e058abcc72aca329414b0edb40ac1b Mon Sep 17 00:00:00 2001
From: Pedro Alves <palves@redhat.com>
Date: Tue, 21 Nov 2017 16:50:32 +0000
Subject: [PATCH] alternative

---
 gdb/eval.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)
  

On 11/21/2017 04:56 PM, Pedro Alves wrote:
> On 11/21/2017 04:42 PM, Pedro Alves wrote:
>> On 11/21/2017 04:23 PM, Sergio Durigan Junior wrote:
> 
>>> Since this is guaranteed to be an stap probe, WDYT about moving this
>>> scoped_restore_current_language to
>>> stap-probe.c:stap_evaluate_probe_argument?  This way we won't be bit by
>>> this problem in other parts that also evaluate arguments of probes.
>>>
>>> Arguably, this should be set for every probe type IMHO, but it's fine if
>>> we just do it for stap probes for now.
>>
>> That sounds like a good idea.  But we could do it in 
>> evaluate_probe_argument then, which handles all probe types?
>>
>> [In your probe C++ification, that translates to evaluate_probe_argument
>> becoming a  non-virtual method of probe, which then calls into a
>> protected virtual method that is overridden by the actual probe
>> implementation (see e.g., the do_xxx methods of class ui_out).]
> 
> Hmm, maybe what we need instead is to make expression evaluation
> never set the selected frame (and thus language as side effect)
> if it wasn't selected/set already.  Like below.  This fixes
> the testcase too.  I'll run the full testsuite now.  WDYT?

Full testsuite run complete; no regressions.

Thanks,
Pedro Alves
  

On Tuesday, November 21 2017, Pedro Alves wrote:

> On 11/21/2017 04:42 PM, Pedro Alves wrote:
>> On 11/21/2017 04:23 PM, Sergio Durigan Junior wrote:
>
>>> Since this is guaranteed to be an stap probe, WDYT about moving this
>>> scoped_restore_current_language to
>>> stap-probe.c:stap_evaluate_probe_argument?  This way we won't be bit by
>>> this problem in other parts that also evaluate arguments of probes.
>>>
>>> Arguably, this should be set for every probe type IMHO, but it's fine if
>>> we just do it for stap probes for now.
>> 
>> That sounds like a good idea.  But we could do it in 
>> evaluate_probe_argument then, which handles all probe types?
>> 
>> [In your probe C++ification, that translates to evaluate_probe_argument
>> becoming a  non-virtual method of probe, which then calls into a
>> protected virtual method that is overridden by the actual probe
>> implementation (see e.g., the do_xxx methods of class ui_out).]
>
> Hmm, maybe what we need instead is to make expression evaluation
> never set the selected frame (and thus language as side effect)
> if it wasn't selected/set already.  Like below.  This fixes
> the testcase too.  I'll run the full testsuite now.  WDYT?

That does look better, indeed.  I was trying to think if we'd encounter
any situation where setting the language is on of the desired effects,
but couldn't think of any.

Thanks,

> From c5fd954787e058abcc72aca329414b0edb40ac1b Mon Sep 17 00:00:00 2001
> From: Pedro Alves <palves@redhat.com>
> Date: Tue, 21 Nov 2017 16:50:32 +0000
> Subject: [PATCH] alternative
>
> ---
>  gdb/eval.c | 12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/gdb/eval.c b/gdb/eval.c
> index 14a3e05..086ac59 100644
> --- a/gdb/eval.c
> +++ b/gdb/eval.c
> @@ -1319,7 +1319,6 @@ evaluate_subexp_standard (struct type *expect_type,
>  
>        {
>  	struct symbol *sym = exp->elts[pc + 1].symbol;
> -	struct frame_info *frame;
>  
>  	if (noside == EVAL_AVOID_SIDE_EFFECTS)
>  	  return value_zero (SYMBOL_TYPE (sym), not_lval);
> @@ -1329,7 +1328,9 @@ evaluate_subexp_standard (struct type *expect_type,
>  	  error (_("Symbol \"%s\" does not have any specific entry value"),
>  		 SYMBOL_PRINT_NAME (sym));
>  
> -	frame = get_selected_frame (NULL);
> +	frame_info *frame = get_selected_frame_if_set ();
> +	if (frame == NULL)
> +	  frame = get_current_frame ();
>  	return SYMBOL_COMPUTED_OPS (sym)->read_variable_at_entry (sym, frame);
>        }
>  
> @@ -1381,7 +1382,12 @@ evaluate_subexp_standard (struct type *expect_type,
>  			+ gdbarch_num_pseudo_regs (exp->gdbarch))
>  	  val = value_zero (register_type (exp->gdbarch, regno), not_lval);
>  	else
> -	  val = value_of_register (regno, get_selected_frame (NULL));
> +	  {
> +	    frame_info *frame = get_selected_frame_if_set ();
> +	    if (frame == NULL)
> +	      frame = get_current_frame ();
> +	    val = value_of_register (regno, frame);
> +	  }
>  	if (val == NULL)
>  	  error (_("Value of register %s not available."), name);
>  	else
> -- 
> 2.5.5
  

n 11/21/2017 05:15 PM, Sergio Durigan Junior wrote:
> On Tuesday, November 21 2017, Pedro Alves wrote:
> 
>> On 11/21/2017 04:42 PM, Pedro Alves wrote:
>>> On 11/21/2017 04:23 PM, Sergio Durigan Junior wrote:
>>
>>>> Since this is guaranteed to be an stap probe, WDYT about moving this
>>>> scoped_restore_current_language to
>>>> stap-probe.c:stap_evaluate_probe_argument?  This way we won't be bit by
>>>> this problem in other parts that also evaluate arguments of probes.
>>>>
>>>> Arguably, this should be set for every probe type IMHO, but it's fine if
>>>> we just do it for stap probes for now.
>>>
>>> That sounds like a good idea.  But we could do it in 
>>> evaluate_probe_argument then, which handles all probe types?
>>>
>>> [In your probe C++ification, that translates to evaluate_probe_argument
>>> becoming a  non-virtual method of probe, which then calls into a
>>> protected virtual method that is overridden by the actual probe
>>> implementation (see e.g., the do_xxx methods of class ui_out).]
>>
>> Hmm, maybe what we need instead is to make expression evaluation
>> never set the selected frame (and thus language as side effect)
>> if it wasn't selected/set already.  Like below.  This fixes
>> the testcase too.  I'll run the full testsuite now.  WDYT?
> 
> That does look better, indeed.  I was trying to think if we'd encounter
> any situation where setting the language is on of the desired effects,
> but couldn't think of any.

Alright, I've sent a v2 now.

Thanks,
Pedro Alves