diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 9f78ed33cc3..50524abd51c 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,13 @@
+2018-02-21  Yao Qi  <yao.qi@linaro.org>
+
+	* regcache.c (regcache::regcache): Call reg_buffer ctor.
+	(regcache::arch): Move it to reg_buffer::arch.
+	(regcache::register_buffer): Likewise.
+	(regcache::assert_regnum): Likewise.
+	(regcache::num_raw_registers): Likewise.
+	* regcache.h (reg_buffer): New class.
+	(regcache): Inherit reg_buffer.
+
 2018-02-20  Simon Marchi  <simon.marchi@ericsson.com>
 
 	* remote-sim.c (gdb_os_printf_filtered, gdb_os_vprintf_filtered,
diff --git a/gdb/regcache.c b/gdb/regcache.c
index ab750c61707..8addc82c68c 100644
--- a/gdb/regcache.c
+++ b/gdb/regcache.c
@@ -181,14 +181,13 @@ regcache_register_size (const struct regcache *regcache, int n)
   return register_size (regcache->arch (), n);
 }
 
-regcache::regcache (gdbarch *gdbarch, const address_space *aspace_,
-		    bool readonly_p_)
-  : m_aspace (aspace_), m_readonly_p (readonly_p_)
+reg_buffer::reg_buffer (gdbarch *gdbarch, bool has_pseudo)
+  : m_has_pseudo (has_pseudo)
 {
   gdb_assert (gdbarch != NULL);
   m_descr = regcache_descr (gdbarch);
 
-  if (m_readonly_p)
+  if (has_pseudo)
     {
       m_registers = XCNEWVEC (gdb_byte, m_descr->sizeof_cooked_registers);
       m_register_status = XCNEWVEC (signed char,
@@ -199,6 +198,16 @@ regcache::regcache (gdbarch *gdbarch, const address_space *aspace_,
       m_registers = XCNEWVEC (gdb_byte, m_descr->sizeof_raw_registers);
       m_register_status = XCNEWVEC (signed char, gdbarch_num_regs (gdbarch));
     }
+}
+
+regcache::regcache (gdbarch *gdbarch, const address_space *aspace_,
+		    bool readonly_p_)
+/* The register buffers.  A read-only register cache can hold the
+   full [0 .. gdbarch_num_regs + gdbarch_num_pseudo_regs) while a
+   read/write register cache can only hold [0 .. gdbarch_num_regs).  */
+  : reg_buffer (gdbarch, readonly_p_),
+    m_aspace (aspace_), m_readonly_p (readonly_p_)
+{
   m_ptid = minus_one_ptid;
 }
 
@@ -218,7 +227,7 @@ regcache::regcache (readonly_t, const regcache &src)
 }
 
 gdbarch *
-regcache::arch () const
+reg_buffer::arch () const
 {
   return m_descr->gdbarch;
 }
@@ -267,7 +276,7 @@ private:
 /* Return  a pointer to register REGNUM's buffer cache.  */
 
 gdb_byte *
-regcache::register_buffer (int regnum) const
+reg_buffer::register_buffer (int regnum) const
 {
   return m_registers + m_descr->register_offset[regnum];
 }
@@ -390,9 +399,13 @@ regcache::invalidate (int regnum)
 }
 
 void
-regcache::assert_regnum (int regnum) const
+reg_buffer::assert_regnum (int regnum) const
 {
-  gdb_assert (regnum >= 0 && regnum < gdbarch_num_regs (arch ()));
+  gdb_assert (regnum >= 0);
+  if (m_has_pseudo)
+    gdb_assert (regnum < m_descr->nr_cooked_registers);
+  else
+    gdb_assert (regnum < gdbarch_num_regs (arch ()));
 }
 
 /* Global structure containing the current regcache.  */
@@ -1272,7 +1285,7 @@ regcache_write_pc (struct regcache *regcache, CORE_ADDR pc)
 }
 
 int
-regcache::num_raw_registers () const
+reg_buffer::num_raw_registers () const
 {
   return gdbarch_num_regs (arch ());
 }
diff --git a/gdb/regcache.h b/gdb/regcache.h
index 9e3da8c3fc5..e2c762119d3 100644
--- a/gdb/regcache.h
+++ b/gdb/regcache.h
@@ -227,9 +227,44 @@ typedef struct cached_reg
   gdb_byte *data;
 } cached_reg_t;
 
+/* Buffer of registers.  */
+
+class reg_buffer
+{
+public:
+  reg_buffer (gdbarch *gdbarch, bool has_pseudo);
+
+  DISABLE_COPY_AND_ASSIGN (reg_buffer);
+
+  /* Return regcache's architecture.  */
+  gdbarch *arch () const;
+
+  virtual ~reg_buffer ()
+  {
+    xfree (m_registers);
+    xfree (m_register_status);
+  }
+
+protected:
+  /* Assert on the range of REGNUM.  */
+  void assert_regnum (int regnum) const;
+
+  int num_raw_registers () const;
+
+  gdb_byte *register_buffer (int regnum) const;
+
+  struct regcache_descr *m_descr;
+
+  bool m_has_pseudo;
+  /* The register buffers.  */
+  gdb_byte *m_registers;
+  /* Register cache status.  */
+  signed char *m_register_status;
+};
+
 /* The register cache for storing raw register values.  */
 
-class regcache
+class regcache : public reg_buffer
 {
 public:
   regcache (gdbarch *gdbarch)
@@ -244,15 +279,6 @@ public:
 
   DISABLE_COPY_AND_ASSIGN (regcache);
 
-  ~regcache ()
-  {
-    xfree (m_registers);
-    xfree (m_register_status);
-  }
-
-  /* Return regcache's architecture.  */
-  gdbarch *arch () const;
-
   /* Return REGCACHE's address space.  */
   const address_space *aspace () const
   {
@@ -339,14 +365,9 @@ public:
   static void regcache_thread_ptid_changed (ptid_t old_ptid, ptid_t new_ptid);
 protected:
   regcache (gdbarch *gdbarch, const address_space *aspace_, bool readonly_p_);
-
-  int num_raw_registers () const;
-
   static std::forward_list<regcache *> current_regcache;
 
 private:
-  gdb_byte *register_buffer (int regnum) const;
-
   void restore (struct regcache *src);
 
   enum register_status xfer_part (int regnum, int offset, int len, void *in,
@@ -357,21 +378,10 @@ private:
 			int regnum, const void *in_buf,
 			void *out_buf, size_t size) const;
 
-  /* Assert on the range of REGNUM.  */
-  void assert_regnum (int regnum) const;
-
-  struct regcache_descr *m_descr;
-
   /* The address space of this register cache (for registers where it
      makes sense, like PC or SP).  */
   const address_space * const m_aspace;
 
-  /* The register buffers.  A read-only register cache can hold the
-     full [0 .. gdbarch_num_regs + gdbarch_num_pseudo_regs) while a read/write
-     register cache can only hold [0 .. gdbarch_num_regs).  */
-  gdb_byte *m_registers;
-  /* Register cache status.  */
-  signed char *m_register_status;
   /* Is this a read-only cache?  A read-only cache is used for saving
      the target's register state (e.g, across an inferior function
      call or just before forcing a function return).  A read-only