Re: [PATCH] Remove some dead code from evaluate_subexp_standard

[Andrew Burgess <andrew.burgess@embecosm.com>]

* Tom Tromey <tom@tromey.com> [2020-11-28 15:43:23 -0700]:

> I noticed that in the OP_ARRAY case in evaluate_subexp_standard,
> "index_pc" is read but never set.  This dead code then guards the only
> call to init_array_element, so this can be removed as well.

For the record index_pc was made redundant in commit:

  commit ae8fddda32d161ea0d8606fdd71349230d5b0ad6
  Date:   Tue Apr 15 11:28:15 2014 +0800

      Remove operator BINOP_RANGE

This change looks good to me, we've clearly not needed this
functionality for the last 6 years!

Thanks,
Andrew


> 
> gdb/ChangeLog
> 2020-11-28  Tom Tromey  <tom@tromey.com>
> 
> 	* eval.c (init_array_element): Remove.
> 	(evaluate_subexp_standard) <OP_ARRAY>: Remove "index_pc".
> ---
>  gdb/ChangeLog |  5 ++++
>  gdb/eval.c    | 64 ++++++---------------------------------------------
>  2 files changed, 12 insertions(+), 57 deletions(-)
> 
> diff --git a/gdb/eval.c b/gdb/eval.c
> index 407d4b4ac59..d02813eec52 100644
> --- a/gdb/eval.c
> +++ b/gdb/eval.c
> @@ -57,10 +57,6 @@ static struct value *evaluate_struct_tuple (struct value *,
>  					    struct expression *, int *,
>  					    enum noside, int);
>  
> -static LONGEST init_array_element (struct value *, struct value *,
> -				   struct expression *, int *, enum noside,
> -				   LONGEST, LONGEST);
> -
>  struct value *
>  evaluate_subexp (struct type *expect_type, struct expression *exp,
>  		 int *pos, enum noside noside)
> @@ -337,39 +333,6 @@ evaluate_struct_tuple (struct value *struct_val,
>    return struct_val;
>  }
>  
> -/* Recursive helper function for setting elements of array tuples.
> -   The target is ARRAY (which has bounds LOW_BOUND to HIGH_BOUND); the
> -   element value is ELEMENT; EXP, POS and NOSIDE are as usual.
> -   Evaluates index expressions and sets the specified element(s) of
> -   ARRAY to ELEMENT.  Returns last index value.  */
> -
> -static LONGEST
> -init_array_element (struct value *array, struct value *element,
> -		    struct expression *exp, int *pos,
> -		    enum noside noside, LONGEST low_bound, LONGEST high_bound)
> -{
> -  LONGEST index;
> -  int element_size = TYPE_LENGTH (value_type (element));
> -
> -  if (exp->elts[*pos].opcode == BINOP_COMMA)
> -    {
> -      (*pos)++;
> -      init_array_element (array, element, exp, pos, noside,
> -			  low_bound, high_bound);
> -      return init_array_element (array, element,
> -				 exp, pos, noside, low_bound, high_bound);
> -    }
> -  else
> -    {
> -      index = value_as_long (evaluate_subexp (nullptr, exp, pos, noside));
> -      if (index < low_bound || index > high_bound)
> -	error (_("tuple index out of range"));
> -      memcpy (value_contents_raw (array) + (index - low_bound) * element_size,
> -	      value_contents (element), element_size);
> -    }
> -  return index;
> -}
> -
>  /* Promote value ARG1 as appropriate before performing a unary operation
>     on this argument.
>     If the result is not appropriate for any particular language then it
> @@ -1433,30 +1396,17 @@ evaluate_subexp_standard (struct type *expect_type,
>  	  for (tem = nargs; --nargs >= 0;)
>  	    {
>  	      struct value *element;
> -	      int index_pc = 0;
>  
>  	      element = evaluate_subexp (element_type, exp, pos, noside);
>  	      if (value_type (element) != element_type)
>  		element = value_cast (element_type, element);
> -	      if (index_pc)
> -		{
> -		  int continue_pc = *pos;
> -
> -		  *pos = index_pc;
> -		  index = init_array_element (array, element, exp, pos, noside,
> -					      low_bound, high_bound);
> -		  *pos = continue_pc;
> -		}
> -	      else
> -		{
> -		  if (index > high_bound)
> -		    /* To avoid memory corruption.  */
> -		    error (_("Too many array elements"));
> -		  memcpy (value_contents_raw (array)
> -			  + (index - low_bound) * element_size,
> -			  value_contents (element),
> -			  element_size);
> -		}
> +	      if (index > high_bound)
> +		/* To avoid memory corruption.  */
> +		error (_("Too many array elements"));
> +	      memcpy (value_contents_raw (array)
> +		      + (index - low_bound) * element_size,
> +		      value_contents (element),
> +		      element_size);
>  	      index++;
>  	    }
>  	  return array;
> -- 
> 2.17.2
>