Re: [patch, fortran] use vec<> in frontend-passes.c

[Trevor Saunders <tsaunders at mozilla dot com>]

On Sun, Aug 24, 2014 at 12:47:17AM +0200, Thomas Koenig wrote:
> Hello world,
> 
> the attached patch uses the vec<> templates instead of the
> home-grown memory management.
> 
> Did I get the style right?  I was a bit confused because, with
> the declarations used in the patch, using the vec_safe_truncate
> function failed with a failure to find the right template.
> I'm not an experienced C++ programmer, so I would appreciate a quick
> look at what I did.
> 
> Regression-tested.  No test case because there is no new
> functionality.
> 
> OK for trunk?  Any other comments?
> 
> 	Thomas
> 
> 2014-08-24  Thomas Koenig  <tkoenig@gcc.gnu.org>
> 
>         * frontend_passes (expr_array):  Replace by vec template.
>         (expr_size):  Remove.
>         (expr_count):  Remove.
>         (doloop_list):  Replace by vec template.
>         (doloop_size):  Remove.
>         (gfc_run_passes):  Adjust to use of vec template.
>         (cfe_register_funcs):  Likewise.
>         (cfe_expr_0):  Likewise.
>         (doloop_code):  Likewise.

> Index: frontend-passes.c
> ===================================================================
> --- frontend-passes.c	(Revision 214281)
> +++ frontend-passes.c	(Arbeitskopie)
> @@ -50,8 +50,7 @@ static int count_arglist;
>  /* Pointer to an array of gfc_expr ** we operate on, plus its size
>     and counter.  */
>  
> -static gfc_expr ***expr_array;
> -static int expr_size, expr_count;
> +static vec<gfc_expr **> expr_array = vec<gfc_expr **>();

that's usually written as just static vec<T> foo; vec doesn't actually
have ctors, and 0 initialization works fine.

>  /* Pointer to the gfc_code we currently work on - to be able to insert
>     a block before the statement.  */
> @@ -81,9 +80,10 @@ static int iterator_level;
>  
>  /* Keep track of DO loop levels.  */
>  
> -static gfc_code **doloop_list;
> -static int doloop_size, doloop_level;
> +static vec<gfc_code *> doloop_list = vec<gfc_code *>();

same

> @@ -101,23 +101,19 @@ gfc_run_passes (gfc_namespace *ns)
>    /* Warn about dubious DO loops where the index might
>       change.  */
>  
> -  doloop_size = 20;
>    doloop_level = 0;
> -  doloop_list = XNEWVEC(gfc_code *, doloop_size);
> +  //  doloop_list = ;

what is this comment supposed to mean?

>    doloop_warn (ns);
> -  XDELETEVEC (doloop_list);
> +  doloop_list.truncate (0);

.release () would be more typical.

>  
>    if (gfc_option.flag_frontend_optimize)
>      {
> -      expr_size = 20;
> -      expr_array = XNEWVEC(gfc_expr **, expr_size);
> -
>        optimize_namespace (ns);
>        optimize_reduction (ns);
>        if (gfc_option.dump_fortran_optimized)
>  	gfc_dump_parse_tree (ns, stdout);
>  
> -      XDELETEVEC (expr_array);
> +      expr_array.truncate (0);

same

> @@ -608,36 +599,35 @@ cfe_expr_0 (gfc_expr **e, int *walk_subtrees,
>        return 0;
>      }
>  
> -  expr_count = 0;
> +  expr_array.truncate (0);

.release ()

>    gfc_expr_walker (e, cfe_register_funcs, NULL);
>  
>    /* Walk through all the functions.  */
>  
> -  for (i=1; i<expr_count; i++)
> +  for (i=1; expr_array.iterate (i, &ei); i++)

FOR_EACH_VEC_ELT, though Its not really clear to my why that's better
than
size_t length = vec.length ();
for (size_t i = 0; i < length; i++)
  // do something with vec[i]

>      {
>        /* Skip if the function has been replaced by a variable already.  */
> -      if ((*(expr_array[i]))->expr_type == EXPR_VARIABLE)
> +      if ((*ei)->expr_type == EXPR_VARIABLE)
>  	continue;
>  
>        newvar = NULL;
> -      for (j=0; j<i; j++)
> +      for (j=0; j<i && expr_array.iterate (j, &ej); j++)

the .iterate call is useless since j must be < i, and the vector is
at least i long right?
Trev