Re: [RFA] dcache.c cleanup

["Doug Evans" <dje@google.com>]

On Thu, Sep 18, 2008 at 3:04 PM, Daniel Jacobowitz <drow@false.org> wrote:
> On Wed, Sep 17, 2008 at 02:44:44PM -0700, Doug Evans wrote:
>> IIRC, "set remotecache" isn't being removed to avoid breaking existing
>> scripts.  It's not used for anything, so this patch marks it as deprecated,
>> and hopefully in a future release we can delete it.
>> [If folks want I can instead submit a patch that makes it useful again -
>> e.g. as an escape hatch in case caching isn't working, it would globally
>> override the mem attribute settings.]
>
> Just my two cents, but I think that the command is useful (even if
> currently broken) - before deprecating it we should have a good idea
> of what to replace it with.  Maybe a non-target-specific command
> and make this a deprecated alias to it.
>
> Should we come up with a coherent picture of the different kinds of
> memory accesses GDB needs?  This is something I've been thinking about
> on and off.  Particular ideas:
>
> - When we are doing prologue analysis, we use symbols from the
> executable (either minimal or full symbols) to find function
> boundaries.  Then we analyze forwards from there.  In every case I can
> think of, this means that we should use the code as present in the
> executable.  It's like trust-readonly-sections, but for only
> prologue analysis reads; the manual disassemble command would still
> show if any code had been corrupted.
>
> - When reading data from the stack for unwinding, we can reliably
> assume that the data is thread-specific and not volatile.  So we
> should be able to cache it automatically, even without user
> instruction, until that thread resumes.  This is like memory
> attributes, but only for stack unwinding.
>
> - If we have memory region descriptions, it's probably safe to assume
> that we have the stack described as RAM.  This is like "set mem
> inaccessible-by-default", but only for stack unwinding.
>
> WDYT - do those make sense?

Sure.

>
>> 2008-09-17  Doug Evans  <dje@google.com>
>>
>>       * dcache.c (state_chars): New static global.
>>       (ENTRY_INVALID,ENTRY_VALID): Renamed from ENTRY_BAD,ENTRY_OK.
>>       All uses updated.
>>       (dcache_info): Print cache state as mnemonically useful letters instead
>>       of magic numbers.
>>       (_initialize_dcache): Mark "set remotecache" as deprecated.
>>       * doc/gdb.texinfo (info dcache): Update.
>
> The changes other than to "set remotecache" look OK to me (remember
> that doc has its own ChangeLog).

Checked in (w/o remotecache).  Thanks.

IWBN to still at least add a comment or some such to the code so the
next person won't look at it and waste time trying errant fixes.