Simplify regcache_dup

regcache_dup, in fact, is to create a readonly regcache from a
non-readonly regcache.  This patch adds an assert that src is not
readonly.

gdb:

2017-04-28  Yao Qi  <yao.qi@linaro.org>

	* regcache.c (regcache_dup): Assert !src->m_readonly_p and
	call method save instead of regcache_cpy.
	* regcache.h (struct regcache): Make regcache_dup a friend.

1 files changed, 2 insertions, 1 deletions

diff --git a/gdb/regcache.c b/gdb/regcache.c
index 11f6a874f3..c30d1c73b8 100644
--- a/gdb/regcache.c
+++ b/gdb/regcache.c
@@ -422,8 +422,9 @@ regcache_dup (struct regcache *src)
 {
   struct regcache *newbuf;
 
+  gdb_assert (!src->m_readonly_p);
   newbuf = regcache_xmalloc (src->arch (), get_regcache_aspace (src));
-  regcache_cpy (newbuf, src);
+  newbuf->save (do_cooked_read, src);
   return newbuf;
 }