Re: [PATCH v3] Support large registers in regcache transfer_regset

[Simon Marchi <simon dot marchi at ericsson dot com>]

Hi Alan,

The patch LGTM.  I noted two small comments you might want to address before
pushing.  Sorry again for the extra work I made you do!

On 2018-06-22 09:08 AM, Alan Hayward wrote:
> @@ -868,6 +900,39 @@ regcache::write_part (int regnum, int offset, int len,
>  
>  /* See regcache.h.  */
>  
> +void
> +reg_buffer::raw_supply_part (int regnum, int offset, int len,
> +			     const gdb_byte *in)
> +{
> +  int reg_size = register_size (arch (), regnum);
> +
> +  gdb_assert (in != nullptr);
> +  gdb_assert (offset >= 0 && offset <= reg_size);
> +  gdb_assert (len >= 0 && offset + len <= reg_size);
> +
> +  if (offset == 0 && len == 0)
> +    {
> +      /* Nothing to do.  */
> +      return;
> +    }
> +
> +  if (offset == 0 && len == reg_size)
> +    {
> +      /* Supply the full register.  */
> +      return raw_supply (regnum, in);
> +    }
> +
> +  gdb_byte *reg = (gdb_byte *) alloca (reg_size);
> +
> +  /* Read when needed.  */
> +  if (offset > 0 || offset + len < reg_size)

I think this if is unneeded now, with the earlier check?  If we reach
this point, it will always be for a partial register.

> diff --git a/gdb/regcache.h b/gdb/regcache.h
> index 983137f6ad..e706d87b54 100644
> --- a/gdb/regcache.h
> +++ b/gdb/regcache.h
> @@ -166,6 +166,10 @@ public:
>    void raw_collect_integer (int regnum, gdb_byte *addr, int addr_len,
>  			    bool is_signed) const;
>  
> +  /* Collect register REGNUM from REGCACHE, starting at offset in REGCACHE,
> +     reading only LEN.  */

I think "starting at offset in REGCACHE" is wrong, you probably meant
"starting at offset in the register" or something like that?

> +  void raw_collect_part (int regnum, int offset, int len, gdb_byte *out) const;
> +
>    /* See common/common-regcache.h.  */
>    void raw_supply (int regnum, const void *buf) override;
>  
> @@ -187,6 +191,10 @@ public:
>       unavailable).  */
>    void raw_supply_zeroed (int regnum);
>  
> +  /* Supply register REGNUM to REGCACHE, starting at offset in REGCACHE, writing
> +     only LEN, without editing the rest of the register.  */

Here too.

Thanks,

Simon