Re: [PATCH] Remove an instance of MAX_REGISTER_SIZE from record-full.c

[Alan Hayward <Alan.Hayward@arm.com>]

> On 12 Jun 2017, at 12:05, Yao Qi <qiyaoltc@gmail.com> wrote:
> 
> Alan Hayward <Alan.Hayward@arm.com> writes:
> 
>> -        regcache_cooked_read (regcache, entry->u.reg.num, reg);
>> -        regcache_cooked_write (regcache, entry->u.reg.num,
>> -			       record_full_get_loc (entry));
>> -        memcpy (record_full_get_loc (entry), reg, entry->u.reg.len);
> 
> The original code is about swapping contents of register REG in regcache
> and record_full_get_loc (entry), and the length is known entry->u.reg.len.
> 

Yes.

>> +	value = regcache->cooked_read_value (entry->u.reg.num);
>> +	gdb_assert (value != NULL);
>> +	regcache->cooked_write (entry->u.reg.num, record_full_get_loc (entry));
>> +	memcpy (record_full_get_loc (entry), value_contents_all (value),
>> +		entry->u.reg.len);
>> +	release_value (value);
>> +	value_free (value);
> 
> It is a overkill to use value to swap these two buffers, IMO.  How about
> xmalloc "reg" instead?
> 

Given that the code doesn’t use any of the error checking, then agreed.


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


Ok to commit?
Alan.

2017-06-12  Alan Hayward  <alan.hayward@arm.com>

	* gdb/record-full.c (record_full_exec_insn): Allocate buffer.


diff --git a/gdb/record-full.c b/gdb/record-full.c
index 31ff558d2a633cff71d3e6082e42f5d6fb88bcf1..4f73e2a5ad0d4a2407b31a1d391e813147e15798 100644
--- a/gdb/record-full.c
+++ b/gdb/record-full.c
@@ -698,7 +698,7 @@ record_full_exec_insn (struct regcache *regcache,
     {
     case record_full_reg: /* reg */
       {
-        gdb_byte reg[MAX_REGISTER_SIZE];
+        gdb_byte *reg = (gdb_byte *) xmalloc (entry->u.reg.len);

         if (record_debug > 1)
           fprintf_unfiltered (gdb_stdlog,
@@ -711,6 +711,7 @@ record_full_exec_insn (struct regcache *regcache,
         regcache_cooked_write (regcache, entry->u.reg.num,
 			       record_full_get_loc (entry));
         memcpy (record_full_get_loc (entry), reg, entry->u.reg.len);
+        xfree (reg);
       }
       break;