Re: [PATCH 8/11] Add FRV_MAX_REGISTER_SIZE

[Alan Hayward <Alan dot Hayward at arm dot com>]

> On 3 May 2017, at 10:27, Pedro Alves <palves@redhat.com> wrote:
> 
> On 05/03/2017 09:44 AM, Yao Qi wrote:
>> Alan Hayward <Alan.Hayward@arm.com> writes:
>> 
>> Hi Alan,
>> regcache.c is updated, so please update your patch.
>> 
>>> I considered making regcache_raw_supply_zero call regcache_raw_supply, but
>>> in the end it made more sense to make it completely separate.
>> 
>> You can call raw_supply (regnum, NULL) and then set the status to REG_VALID.
>> 
> 
> I think I agree with Alan -- if we defer to raw_supply, then I'd still prefer
> that the memset is still done in regcache_raw_supply_zero, because whether
> unavailable registers actually have a contents buffer at all is
> implementation detail.  We currently zero REG_UNVAILABLE registers in raw_supply,
> but that could change.  (And if we reuse raw_supply as is, then memset, we'll
> memset twice.)
> 
> BTW, note that gdbserver has an equivalent function, called
> "supply_register_zeroed".
> 

Agreed. I didn't want somebody in the future to change raw_supply and cause
raw_supply_zero to break.

Patch updated to head and raw_supply_zero moved into regcache class.

Tested on a --enable-targets=all using make check with board files
unix and native-gdbserver.

Ok to commit?

Alan.

2017-05-03  Alan Hayward  <alan.hayward@arm.com>

	* frv-linux-tdep.c (frv_linux_supply_gregset): Use raw_supply_zero.
	* regcache.c (regcache::raw_supply_zero): New function.
	* regcache.h (regcache::raw_supply_zero: New declaration.


diff --git a/gdb/frv-linux-tdep.c b/gdb/frv-linux-tdep.c
index eb87f93058b0287e8f05c585d1b6aa1ff2bffb78..30e5bf00c199a0193ea6cac3a14070445492d3fe 100644
--- a/gdb/frv-linux-tdep.c
+++ b/gdb/frv-linux-tdep.c
@@ -413,17 +413,14 @@ frv_linux_supply_gregset (const struct regset *regset,
 			  int regnum, const void *gregs, size_t len)
 {
   int regi;
-  char zerobuf[MAX_REGISTER_SIZE];
-
-  memset (zerobuf, 0, MAX_REGISTER_SIZE);

   /* gr0 always contains 0.  Also, the kernel passes the TBR value in
      this slot.  */
-  regcache_raw_supply (regcache, first_gpr_regnum, zerobuf);
+  regcache->raw_supply_zero (first_gpr_regnum);

   /* Fill gr32, ..., gr63 with zeros. */
   for (regi = first_gpr_regnum + 32; regi <= last_gpr_regnum; regi++)
-    regcache_raw_supply (regcache, regi, zerobuf);
+    regcache->raw_supply_zero (regi);

   regcache_supply_regset (regset, regcache, regnum, gregs, len);
 }
diff --git a/gdb/regcache.h b/gdb/regcache.h
index 346d290b752d8809f78b72c104ccbc2f5574d83c..ee949597d5691b692b1162a92bc328266fdc160a 100644
--- a/gdb/regcache.h
+++ b/gdb/regcache.h
@@ -296,6 +296,8 @@ public:

   void raw_supply (int regnum, const void *buf);

+  void raw_supply_zero (int regnum);
+
   void raw_copy (int regnum, struct regcache *src_regcache);

   enum register_status get_register_status (int regnum) const;
diff --git a/gdb/regcache.c b/gdb/regcache.c
index 748c30e2d4c5f572e9741f73a39c4bc555d1d663..89c2eb55e29af9a806a684382dc928c307ff934b 100644
--- a/gdb/regcache.c
+++ b/gdb/regcache.c
@@ -1208,6 +1208,26 @@ regcache::raw_supply (int regnum, const void *buf)
     }
 }

+/* Supply register REGNUM with zeroed value to REGCACHE.  This is not the same
+   as calling raw_supply with NULL (which will set the state to
+   unavailable).  */
+
+void
+regcache::raw_supply_zero (int regnum)
+{
+  void *regbuf;
+  size_t size;
+
+  gdb_assert (regnum >= 0 && regnum < m_descr->nr_raw_registers);
+  gdb_assert (!m_readonly_p);
+
+  regbuf = register_buffer (regnum);
+  size = m_descr->sizeof_register[regnum];
+
+  memset (regbuf, 0, size);
+  m_register_status[regnum] = REG_VALID;
+}
+
 /* Collect register REGNUM from REGCACHE and store its contents in BUF.  */

 void