[commit] Allow cached cooked reads

[commit] Allow cached cooked reads

[Andrew Cagney]

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Just stumbled across this.  When trying to save cooked registers the 
regcache was triggering an assertion failure instead of ignoring a bogus 
request.

committed,
Andrew

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2003-06-16  Andrew Cagney  <cagney@redhat.com>

	* regcache.c (do_cooked_read): Do not use register_valid_p.

Index: regcache.c
===================================================================
RCS file: /cvs/src/src/gdb/regcache.c,v
retrieving revision 1.87
diff -u -r1.87 regcache.c
--- regcache.c	9 Jun 2003 01:02:06 -0000	1.87
+++ regcache.c	16 Jun 2003 13:18:46 -0000
@@ -423,8 +423,7 @@
 do_cooked_read (void *src, int regnum, void *buf)
 {
   struct regcache *regcache = src;
-  if (!regcache_valid_p (regcache, regnum)
-      && regcache->readonly_p)
+  if (!regcache->register_valid_p[regnum] && regcache->readonly_p)
     /* Don't even think about fetching a register from a read-only
        cache when the register isn't yet valid.  There isn't a target
        from which the register value can be fetched.  */

Re: [commit] Allow cached cooked reads

[Kevin Buettner]

On Jun 16,  9:22am, Andrew Cagney wrote:

> Just stumbled across this.  When trying to save cooked registers the 
> regcache was triggering an assertion failure instead of ignoring a bogus 
> request.
> 
> 2003-06-16  Andrew Cagney  <cagney@redhat.com>
> 
> 	* regcache.c (do_cooked_read): Do not use register_valid_p.
> 
> Index: regcache.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/regcache.c,v
> retrieving revision 1.87
> diff -u -r1.87 regcache.c
> --- regcache.c	9 Jun 2003 01:02:06 -0000	1.87
> +++ regcache.c	16 Jun 2003 13:18:46 -0000
> @@ -423,8 +423,7 @@
>  do_cooked_read (void *src, int regnum, void *buf)
>  {
>    struct regcache *regcache = src;
> -  if (!regcache_valid_p (regcache, regnum)
> -      && regcache->readonly_p)
> +  if (!regcache->register_valid_p[regnum] && regcache->readonly_p)
>      /* Don't even think about fetching a register from a read-only
>         cache when the register isn't yet valid.  There isn't a target
>         from which the register value can be fetched.  */

Which assertion was failing?  The check for regcache != NULL or the
bounds check?

I'm wondering if the new code above should include some bounds checks. 
Alternately, go back to using regcache_valid_p() and weaken the
assertions in regcache_valid_p() somewhat.  E.g, perhaps rewrite
regcache_valid_p() from:

int
regcache_valid_p (struct regcache *regcache, int regnum)
{
  gdb_assert (regcache != NULL);
  gdb_assert (regnum >= 0 && regnum < regcache->descr->nr_raw_registers);
  return regcache->register_valid_p[regnum];
}

to:

int
regcache_valid_p (struct regcache *regcache, int regnum)
{
  gdb_assert (regcache != NULL);
  gdb_assert (regnum >= 0);
  return regnum < regcache->descr->nr_raw_registers)
         && regcache->register_valid_p[regnum];
}

Kevin

Re: [commit] Allow cached cooked reads

[Andrew Cagney]

> On Jun 16,  9:22am, Andrew Cagney wrote:
> 
> 
>> Just stumbled across this.  When trying to save cooked registers the 
>> regcache was triggering an assertion failure instead of ignoring a bogus 
>> request.
>> 
>> 2003-06-16  Andrew Cagney  <cagney@redhat.com>
>> 
>> 	* regcache.c (do_cooked_read): Do not use register_valid_p.
>> 
>> Index: regcache.c
>> ===================================================================
>> RCS file: /cvs/src/src/gdb/regcache.c,v
>> retrieving revision 1.87
>> diff -u -r1.87 regcache.c
>> --- regcache.c	9 Jun 2003 01:02:06 -0000	1.87
>> +++ regcache.c	16 Jun 2003 13:18:46 -0000
>> @@ -423,8 +423,7 @@
>>  do_cooked_read (void *src, int regnum, void *buf)
>>  {
>>    struct regcache *regcache = src;
>> -  if (!regcache_valid_p (regcache, regnum)
>> -      && regcache->readonly_p)
>> +  if (!regcache->register_valid_p[regnum] && regcache->readonly_p)
>>      /* Don't even think about fetching a register from a read-only
>>         cache when the register isn't yet valid.  There isn't a target
>>         from which the register value can be fetched.  */
> 
> 
> Which assertion was failing?  The check for regcache != NULL or the
> bounds check?

The bounds check.  If regcache were NULL, GDB would be sunk.

> I'm wondering if the new code above should include some bounds checks. 
> Alternately, go back to using regcache_valid_p() and weaken the
> assertions in regcache_valid_p() somewhat.  E.g, perhaps rewrite
> regcache_valid_p() from:



> int
> regcache_valid_p (struct regcache *regcache, int regnum)
> {
>   gdb_assert (regcache != NULL);
>   gdb_assert (regnum >= 0 && regnum < regcache->descr->nr_raw_registers);
>   return regcache->register_valid_p[regnum];
> }
> 
> to:
> 
> int
> regcache_valid_p (struct regcache *regcache, int regnum)
> {
>   gdb_assert (regcache != NULL);
>   gdb_assert (regnum >= 0);
>   return regnum < regcache->descr->nr_raw_registers)
>          && regcache->register_valid_p[regnum];
> }

The intent of the external function is to indicate to external code if a 
raw register is valid (as in fetched).  So external code trying to call 
this with regnum >= NUM_REGS is broken.

Andrew