Simplify regcache_cpy and remove regcache::cpy_no_passthrough

  Alan Hayward <Alan.Hayward@arm.com> writes:

> If not, then there should be a comment above regcache_cpy stating the
> restrictions.

I updated the comments to regcache_dup and regcache_cpy.
  

> On 17 Jul 2017, at 12:32, Yao Qi <qiyaoltc@gmail.com> wrote:

> 

> Alan Hayward <Alan.Hayward@arm.com> writes:

> 

>> If not, then there should be a comment above regcache_cpy stating the

>> restrictions.

> 

> I updated the comments to regcache_dup and regcache_cpy.


Ok for me.


> 

> -- 

> Yao (齐尧)

> From 4ff91e90cad73f9420f8ca37fc7e22f465ebcb88 Mon Sep 17 00:00:00 2001

> From: Yao Qi <yao.qi@linaro.org>

> Date: Mon, 19 Jun 2017 22:45:12 +0100

> Subject: [PATCH] Simplify regcache_cpy and remove regcache::cpy_no_passthrough

> 

> Nowadays, regcache_cpy is used where src is read-only and dst is not

> read-only, so the regcache_cpy can be simplified to handle this case only.

> As a result, regcache::cpy_no_passthrough, which is about two read-only

> regcache copy, is no longer used, remove it as well.

> 

> gdb:

> 

> 2017-07-17  Yao Qi  <yao.qi@linaro.org>

> 

> 	* regcache.c (regcache_cpy): Simplify it.

> 	(regcache::cpy_no_passthrough): Remove it.

> 	* regcache.h (cpy_no_passthrough): Remove it.

> 	(regcache_dup, regcache_cpy): Update comments.

> 

> diff --git a/gdb/regcache.c b/gdb/regcache.c

> index 7eeb737..e8f92d6 100644

> --- a/gdb/regcache.c

> +++ b/gdb/regcache.c

> @@ -388,36 +388,9 @@ regcache_cpy (struct regcache *dst, struct regcache *src)

>   gdb_assert (src != NULL && dst != NULL);

>   gdb_assert (src->m_descr->gdbarch == dst->m_descr->gdbarch);

>   gdb_assert (src != dst);

> -  gdb_assert (src->m_readonly_p || dst->m_readonly_p);

> +  gdb_assert (src->m_readonly_p && !dst->m_readonly_p);

> 

> -  if (!src->m_readonly_p)

> -    regcache_save (dst, do_cooked_read, src);

> -  else if (!dst->m_readonly_p)

> -    dst->restore (src);

> -  else

> -    dst->cpy_no_passthrough (src);

> -}

> -

> -/* Copy/duplicate the contents of a register cache.  Unlike regcache_cpy,

> -   which is pass-through, this does not go through to the target.

> -   Only values values already in the cache are transferred.  The SRC and DST

> -   buffers must not overlap.  */

> -

> -void

> -regcache::cpy_no_passthrough (struct regcache *src)

> -{

> -  gdb_assert (src != NULL);

> -  gdb_assert (src->m_descr->gdbarch == m_descr->gdbarch);

> -  /* NOTE: cagney/2002-05-17: Don't let the caller do a no-passthrough

> -     move of data into a thread's regcache.  Doing this would be silly

> -     - it would mean that regcache->register_status would be

> -     completely invalid.  */

> -  gdb_assert (m_readonly_p && src->m_readonly_p);

> -

> -  memcpy (m_registers, src->m_registers,

> -	  m_descr->sizeof_cooked_registers);

> -  memcpy (m_register_status, src->m_register_status,

> -	  m_descr->sizeof_cooked_register_status);

> +  dst->restore (src);

> }

> 

> struct regcache *

> diff --git a/gdb/regcache.h b/gdb/regcache.h

> index b416d5e..aa64a00 100644

> --- a/gdb/regcache.h

> +++ b/gdb/regcache.h

> @@ -369,8 +369,6 @@ private:

> 

>   void restore (struct regcache *src);

> 

> -  void cpy_no_passthrough (struct regcache *src);

> -

>   enum register_status xfer_part (int regnum, int offset, int len, void *in,

> 				  const void *out,

> 				  decltype (regcache_raw_read) read,

> @@ -415,13 +413,12 @@ private:

>   regcache_cpy (struct regcache *dst, struct regcache *src);

> };

> 

> -/* Copy/duplicate the contents of a register cache.  By default, the

> -   operation is pass-through.  Writes to DST and reads from SRC will

> -   go through to the target.  See also regcache_cpy_no_passthrough.

> -

> -   regcache_cpy can not have overlapping SRC and DST buffers.  */

> -

> +/* Duplicate the contents of a register cache to a read-only register

> +   cache.  The operation is pass-through.  */

> extern struct regcache *regcache_dup (struct regcache *regcache);

> +

> +/* Writes to DEST will go through to the target.  SRC is a read-only

> +   register cache.  */

> extern void regcache_cpy (struct regcache *dest, struct regcache *src);

> 

> extern void registers_changed (void);
  

Alan Hayward <Alan.Hayward@arm.com> writes:

>> I updated the comments to regcache_dup and regcache_cpy.
>
> Ok for me.

I pushed it in.