Re: [PATCH] gdb/amd64: clean up unused variable

[John Baldwin <jhb@FreeBSD.org>]

On 7/30/22 9:14 PM, Enze Li via Gdb-patches wrote:
> When building with clang 15, I got this,
> 
>    CXX    amd64-tdep.o
> amd64-tdep.c:1410:13: error: variable 'insn' set but not used[-Werror,-Wunused-but-set-variable]
>      gdb_byte *insn = insn_details->raw_insn + modrm_offset;
>                  ^
> 1 error generated.
> 
> The function that uses this variable has been removed in this commit,
> 
> commit 870f88f7551b0f2d6aaaa36fb684b5ff8f468107
> Date:   Mon Apr 18 13:16:27 2016 -0400
> 
>      remove trivialy unused variables
> 
> Fix this by removing unused variable.
> 
> Tested by rebuilding on x86_64-linux with clang 15 and gcc 12.
> ---
>   gdb/amd64-tdep.c | 2 --
>   1 file changed, 2 deletions(-)
> 
> diff --git a/gdb/amd64-tdep.c b/gdb/amd64-tdep.c
> index 0563b32a54bf..3fbbf20fc2b1 100644
> --- a/gdb/amd64-tdep.c
> +++ b/gdb/amd64-tdep.c
> @@ -1407,14 +1407,12 @@ fixup_riprel (struct gdbarch *gdbarch,
>   {
>     const struct amd64_insn *insn_details = &dsc->insn_details;
>     int modrm_offset = insn_details->modrm_offset;
> -  gdb_byte *insn = insn_details->raw_insn + modrm_offset;
>     CORE_ADDR rip_base;
>     int insn_length;
>     int arch_tmp_regno, tmp_regno;
>     ULONGEST orig_value;
>   
>     /* %rip+disp32 addressing mode, displacement follows ModRM byte.  */
> -  ++insn;

This seems to orphan the comment.  I think the comment can go.  insn here
was orphaned by commit 870f88f7551b0f2d6aaaa36fb684b5ff8f468107 which
removed a different unused variable (disp) fetched from the modified
insn location and which held the displacement value referenced by the comment.
    
>     /* Compute the rip-relative address.	*/
>     insn_length = gdb_buffered_insn_length (gdbarch, dsc->insn_buf.data (),


-- 
John Baldwin