Re: [PATCH] Remove 'target_mach' global from score-tdep.c

[Andrew Burgess <aburgess@redhat.com>]

Tom Tromey <tom@tromey.com> writes:

> I randomly noticed that score-tdep.c sets a global variable from
> score_gdbarch_init, and then reuses this in other spots in the file.
>
> This seems incorrect to me, at least if multiple inferiors or targets
> are used; or potentially if there is a single gdb session that
> switches back and forth between (sub-)architectures, causing the
> global to be invalid.
>
> This patch fixes the problem by deferring the lookup.
>
> I wrote this just based on inspection, though, and have no way to test
> it.  I wonder if other *-tdep.c files have similar issues.

I know nothing about the score architecture, but just by inspection this
change looks good to me.

Thanks,
Andrew


> ---
>  gdb/score-tdep.c | 26 ++++++++++++++++----------
>  1 file changed, 16 insertions(+), 10 deletions(-)
>
> diff --git a/gdb/score-tdep.c b/gdb/score-tdep.c
> index e20bee46df9..b5bc47ab694 100644
> --- a/gdb/score-tdep.c
> +++ b/gdb/score-tdep.c
> @@ -53,13 +53,18 @@ struct score_frame_cache
>    trad_frame_saved_reg *saved_regs;
>  };
>  
> -static int target_mach = bfd_mach_score7;
> +/* Return the bfd_mach_* value for GDBARCH.  */
> +static int
> +target_mach (struct gdbarch *gdbarch)
> +{
> +  return gdbarch_bfd_arch_info (gdbarch)->mach;
> +}
>  
>  static struct type *
>  score_register_type (struct gdbarch *gdbarch, int regnum)
>  {
>    gdb_assert (regnum >= 0 
> -	      && regnum < ((target_mach == bfd_mach_score7)
> +	      && regnum < ((target_mach (gdbarch) == bfd_mach_score7)
>  			   ? SCORE7_NUM_REGS : SCORE3_NUM_REGS));
>    return builtin_type (gdbarch)->builtin_uint32;
>  }
> @@ -108,7 +113,7 @@ static int
>  score_register_sim_regno (struct gdbarch *gdbarch, int regnum)
>  {
>    gdb_assert (regnum >= 0 
> -	      && regnum < ((target_mach == bfd_mach_score7)
> +	      && regnum < ((target_mach (gdbarch) == bfd_mach_score7)
>  			   ? SCORE7_NUM_REGS : SCORE3_NUM_REGS));
>    return regnum;
>  }
> @@ -388,7 +393,7 @@ score_adjust_breakpoint_address (struct gdbarch *gdbarch, CORE_ADDR bpaddr)
>  {
>    CORE_ADDR adjust_pc = bpaddr; 
>  
> -  if (target_mach == bfd_mach_score3)
> +  if (target_mach (gdbarch) == bfd_mach_score3)
>      score3_adjust_pc_and_fetch_inst (&adjust_pc, NULL,
>  		    		     gdbarch_byte_order (gdbarch));
>    else
> @@ -404,13 +409,14 @@ score_frame_align (struct gdbarch *gdbarch, CORE_ADDR addr)
>  }
>  
>  static void
> -score_xfer_register (struct regcache *regcache, int regnum, int length,
> +score_xfer_register (struct gdbarch *gdbarch,
> +		     struct regcache *regcache, int regnum, int length,
>  		     enum bfd_endian endian, gdb_byte *readbuf,
>  		     const gdb_byte *writebuf, int buf_offset)
>  {
>    int reg_offset = 0;
>    gdb_assert (regnum >= 0 
> -	      && regnum < ((target_mach == bfd_mach_score7)
> +	      && regnum < ((target_mach (gdbarch) == bfd_mach_score7)
>  			   ? SCORE7_NUM_REGS : SCORE3_NUM_REGS));
>  
>    switch (endian)
> @@ -458,7 +464,7 @@ score_return_value (struct gdbarch *gdbarch, struct value *function,
>  
>  	  if (offset + xfer > TYPE_LENGTH (type))
>  	    xfer = TYPE_LENGTH (type) - offset;
> -	  score_xfer_register (regcache, regnum, xfer,
> +	  score_xfer_register (gdbarch, regcache, regnum, xfer,
>  			       gdbarch_byte_order(gdbarch),
>  			       readbuf, writebuf, offset);
>  	}
> @@ -1317,7 +1323,8 @@ score_make_prologue_cache (struct frame_info *this_frame, void **this_cache)
>      if (start_addr == 0)
>        return cache;
>  
> -    if (target_mach == bfd_mach_score3)
> +    struct gdbarch *gdbarch = get_frame_arch (this_frame);
> +    if (target_mach (gdbarch) == bfd_mach_score3)
>        score3_analyze_prologue (start_addr, pc, this_frame,
>  			       (struct score_frame_cache *) *this_cache);
>      else
> @@ -1447,7 +1454,6 @@ static struct gdbarch *
>  score_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
>  {
>    struct gdbarch *gdbarch;
> -  target_mach = info.bfd_arch_info->mach;
>  
>    arches = gdbarch_list_lookup_by_info (arches, &info);
>    if (arches != NULL)
> @@ -1472,7 +1478,7 @@ score_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
>    set_gdbarch_frame_align (gdbarch, score_frame_align);
>    set_gdbarch_inner_than (gdbarch, core_addr_lessthan);
>  
> -  switch (target_mach)
> +  switch (info.bfd_arch_info->mach)
>      {
>      case bfd_mach_score7:
>        set_gdbarch_breakpoint_kind_from_pc (gdbarch,
> -- 
> 2.34.1