Use std::unique_ptr in reg_buffer

Using std::unique_ptr allows to remove the manual xfree in the
destructor.

If I understand correctly, using the () after the new operator will make
sure the allocated objects will be value initialized, which for scalars
means they are zero-initialized.  So it should have the same behavior as
XCNEWVEC.

gdb/ChangeLog:

	* regcache.h (reg_buffer) <~reg_buffer>: Use default destructor.
	<m_registers, m_register_status>: Change type to
	std::unique_ptr.
	* regcache.c (reg_buffer::reg_buffer): Use new instead of
	XCNEWVEC.

3 files changed, 21 insertions, 16 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index c475cd9..1600232 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,13 @@
 2018-06-09  Simon Marchi  <simon.marchi@ericsson.com>
 
+	* regcache.h (reg_buffer) <~reg_buffer>: Use default destructor.
+	<m_registers, m_register_status>: Change type to
+	std::unique_ptr.
+	* regcache.c (reg_buffer::reg_buffer): Use new instead of
+	XCNEWVEC.
+
+2018-06-09  Simon Marchi  <simon.marchi@ericsson.com>
+
 	* common/common-regcache.h (enum register_status): Add
 	underlying type "signed char".
 	* regcache.h (reg_buffer) <m_register_status>: Change type to
diff --git a/gdb/regcache.c b/gdb/regcache.c
index 626d424..3eed7b6 100644
--- a/gdb/regcache.c
+++ b/gdb/regcache.c
@@ -185,15 +185,15 @@ reg_buffer::reg_buffer (gdbarch *gdbarch, bool has_pseudo)
 
   if (has_pseudo)
     {
-      m_registers = XCNEWVEC (gdb_byte, m_descr->sizeof_cooked_registers);
-      m_register_status
-	= XCNEWVEC (register_status, m_descr->nr_cooked_registers);
+      m_registers.reset (new gdb_byte[m_descr->sizeof_cooked_registers] ());
+      m_register_status.reset
+	(new register_status[m_descr->nr_cooked_registers] ());
     }
   else
     {
-      m_registers = XCNEWVEC (gdb_byte, m_descr->sizeof_raw_registers);
-      m_register_status
-	= XCNEWVEC (register_status, gdbarch_num_regs (gdbarch));
+      m_registers.reset (new gdb_byte[m_descr->sizeof_raw_registers] ());
+      m_register_status.reset
+	(new register_status[gdbarch_num_regs (gdbarch)] ());
     }
 }
 
@@ -260,7 +260,7 @@ private:
 gdb_byte *
 reg_buffer::register_buffer (int regnum) const
 {
-  return m_registers + m_descr->register_offset[regnum];
+  return m_registers.get () + m_descr->register_offset[regnum];
 }
 
 void
@@ -273,8 +273,8 @@ reg_buffer::save (regcache_cooked_read_ftype *cooked_read,
   /* It should have pseudo registers.  */
   gdb_assert (m_has_pseudo);
   /* Clear the dest.  */
-  memset (m_registers, 0, m_descr->sizeof_cooked_registers);
-  memset (m_register_status, REG_UNKNOWN, m_descr->nr_cooked_registers);
+  memset (m_registers.get (), 0, m_descr->sizeof_cooked_registers);
+  memset (m_register_status.get (), REG_UNKNOWN, m_descr->nr_cooked_registers);
   /* Copy over any registers (identified by their membership in the
      save_reggroup) and mark them as valid.  The full [0 .. gdbarch_num_regs +
      gdbarch_num_pseudo_regs) range is checked since some architectures need
diff --git a/gdb/regcache.h b/gdb/regcache.h
index 1001eed..2f460a0 100644
--- a/gdb/regcache.h
+++ b/gdb/regcache.h
@@ -153,11 +153,8 @@ public:
      buffer.  */
   enum register_status get_register_status (int regnum) const;
 
-  virtual ~reg_buffer ()
-  {
-    xfree (m_registers);
-    xfree (m_register_status);
-  }
+  virtual ~reg_buffer () = default;
+
 protected:
   /* Assert on the range of REGNUM.  */
   void assert_regnum (int regnum) const;
@@ -175,9 +172,9 @@ protected:
 
   bool m_has_pseudo;
   /* The register buffers.  */
-  gdb_byte *m_registers;
+  std::unique_ptr<gdb_byte[]> m_registers;
   /* Register cache status.  */
-  register_status *m_register_status;
+  std::unique_ptr<register_status[]> m_register_status;
 
   friend class regcache;
   friend class detached_regcache;