[PATCH] gdb/amd64: clean up unused variable

[PATCH] gdb/amd64: clean up unused variable

[Enze Li via Gdb-patches]

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;
 
   /* Compute the rip-relative address.	*/
   insn_length = gdb_buffered_insn_length (gdbarch, dsc->insn_buf.data (),
-- 
2.37.1

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

[John Baldwin]

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

[PATCH v2] gdb/amd64: clean up unused variable

[Enze Li via Gdb-patches]

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 | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/gdb/amd64-tdep.c b/gdb/amd64-tdep.c
index 0563b32a54b..d89e06d27cb 100644
--- a/gdb/amd64-tdep.c
+++ b/gdb/amd64-tdep.c
@@ -1407,15 +1407,11 @@ 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;
-
   /* Compute the rip-relative address.	*/
   insn_length = gdb_buffered_insn_length (gdbarch, dsc->insn_buf.data (),
 					  dsc->insn_buf.size (), from);
-- 
2.37.1

Re: [PATCH v2] gdb/amd64: clean up unused variable

[John Baldwin]

On 8/1/22 3:23 PM, Enze Li 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,

LGTM, and I think this is obvious enough you can push it.

-- 
John Baldwin

Re: [PATCH v2] gdb/amd64: clean up unused variable

[Enze Li via Gdb-patches]

On Tue, 2022-08-02 at 08:44 -0700, John Baldwin wrote:
> On 8/1/22 3:23 PM, Enze Li 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,
> 
> LGTM, and I think this is obvious enough you can push it.
> 

Thanks, John.  Pushed.

Enze