Re: [PATCH] gdb: Remove unused extra_lines variable

[Bruno Larsen <blarsen@redhat.com>]

On 25/09/2022 10:17, Tsukasa OI via Gdb-patches wrote:
> Clang generates a warning if there is a variable that is set but not used
> otherwise ("-Wunused-but-set-variable").  On the default configuration, it
> causes a build failure (unless "--disable-werror" is specified).
>
> The only extra_lines use in arrange_linetable function is removed on the
> commit 558802e4d1c5dcbd0df7d2c6ef62a6deac247a2f
> ("gdb: change subfile::line_vector to an std::vector").  So, this variable
> should be removed to prevent a build failure.

Hi Tsukasa!

This patch looks pretty safe. The point at which extra_lines would be 
used has the exact same check used to set it, instead of using the 
variable, so I think there is no need for it after all.

That said, I can't approve the patch for pushing, so I hope a maintainer 
looks at this soon.

>
> gdb/ChangeLog:
>
> 	* xcoffread.c (arrange_linetable): Remove unused extra_lines.
side note, GDB doesn't require changelogs anymore, but there are no 
rules against it, so you can leave it here if you'd like.

Cheers,
Bruno

> ---
>   gdb/xcoffread.c | 8 --------
>   1 file changed, 8 deletions(-)
>
> diff --git a/gdb/xcoffread.c b/gdb/xcoffread.c
> index b7d65771115..aa88cbc724d 100644
> --- a/gdb/xcoffread.c
> +++ b/gdb/xcoffread.c
> @@ -419,8 +419,6 @@ add_stab_to_list (char *stabname, struct pending_stabs **stabvector)
>   static void
>   arrange_linetable (std::vector<linetable_entry> &old_linetable)
>   {
> -  int extra_lines = 0;
> -
>     std::vector<linetable_entry> fentries;
>   
>     for (int ii = 0; ii < old_linetable.size (); ++ii)
> @@ -436,12 +434,6 @@ arrange_linetable (std::vector<linetable_entry> &old_linetable)
>   	  e.line = ii;
>   	  e.is_stmt = 1;
>   	  e.pc = old_linetable[ii].pc;
> -
> -	  /* If the function was compiled with XLC, we may have to add an
> -	     extra line entry later.  Reserve space for that.  */
> -	  if (ii + 1 < old_linetable.size ()
> -	      && old_linetable[ii].pc != old_linetable[ii + 1].pc)
> -	    extra_lines++;
>   	}
>       }
>   
>
> base-commit: 58d69206b8173b9d027a6c65f56cdaf045ae6e64