Re: [RFA 03/11] Remove cleanups from mi-cmd-var.c

[Pedro Alves <palves at redhat dot com>]

On 09/12/2017 07:57 PM, Tom Tromey wrote:

> diff --git a/gdb/mi/mi-cmd-var.c b/gdb/mi/mi-cmd-var.c
> index 8b22b2f..b628814 100644
> --- a/gdb/mi/mi-cmd-var.c
> +++ b/gdb/mi/mi-cmd-var.c
> @@ -95,32 +95,21 @@ mi_cmd_var_create (const char *command, char **argv, int argc)
>    struct ui_out *uiout = current_uiout;
>    CORE_ADDR frameaddr = 0;
>    struct varobj *var;
> -  char *name;
>    char *frame;
>    char *expr;
> -  struct cleanup *old_cleanups;
>    enum varobj_type var_type;
>  
>    if (argc != 3)
>      error (_("-var-create: Usage: NAME FRAME EXPRESSION."));
>  
> -  name = xstrdup (argv[0]);
> -  /* Add cleanup for name. Must be free_current_contents as name can
> -     be reallocated.  */
> -  old_cleanups = make_cleanup (free_current_contents, &name);
> -
> -  frame = xstrdup (argv[1]);
> -  make_cleanup (xfree, frame);
> +  std::string name = argv[0];
>  
> -  expr = xstrdup (argv[2]);
> -  make_cleanup (xfree, expr);
> +  frame = argv[1];
> +  expr = argv[2];
>  
> -  if (strcmp (name, "-") == 0)
> -    {
> -      xfree (name);
> -      name = varobj_gen_name ();
> -    }
> -  else if (!isalpha (*name))
> +  if (name == "-")
> +    name = varobj_gen_name ();
> +  else if (!isalpha (name[0]))
>      error (_("-var-create: name of object must begin with a letter"));

name was a deep copy of argv[0] up to here.  That copy
appears unnecessary, if you write it like this:

  std::string name;

  if (strcmp (argv[0], "-") == 0)
    name = varobj_gen_name ();
  else if (!isalpha (*argv[0]))
    error (_("-var-create: name of object must begin with a letter"));
  else
    name = argv[0];

There's still a deep copy in that last else above.
We should be able to get rid of that like this:

  const char *name;
  std::string gen_name;

  if (strcmp (argv[0], "-") == 0)
    {
      gen_name = varobj_gen_name ();
      name = gen_name.c_str ();
    }
  else if (!isalpha (*argv[0]))
    error (_("-var-create: name of object must begin with a letter"));
  else
    name = argv[0];

Otherwise OK.

Thanks,
Pedro Alves