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

Alan Hayward
2017-06-12T13:59:55Z

> 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;