On Wed, Dec 18, 2013 at 9:28 AM, Xinliang David Li <davi...@google.com> wrote:
>>>
>>> #ifdef L_gcov_merge_ior
>>> /* The profile merging function that just adds the counters. It is given
>>> - an array COUNTERS of N_COUNTERS old counters and it reads the same
>>> number
>>> - of counters from the gcov file. */
>>> + an array COUNTERS of N_COUNTERS old counters.
>>> + When SRC==NULL, it reads the same number of counters from the gcov file.
>>> + Otherwise, it reads from SRC array. */
>>> void
>>> -__gcov_merge_ior (gcov_type *counters, unsigned n_counters)
>>> +__gcov_merge_ior (gcov_type *counters, unsigned n_counters,
>>> + gcov_type *src, unsigned w __attribute__ ((unused)))
>>
>> So the new in-memory variants are introduced for merging tool, while libgcc
>> use gcov_read_counter
>> interface?
>> Perhaps we can actually just duplicate the functions to avoid runtime to do
>> all the scalling
>> and in_mem tests it won't need?
>
>
> I thought about this one a little. How about making the interface
> change conditionally, but still share the implementation? The merge
> function bodies mostly remain unchanged and there is no runtime
> penalty for libgcov. The new macros can be shared across most of the
> mergers.
>
> #ifdef IN_PREOFILE_TOOL
> #define GCOV_MERGE_EXTRA_ARGS gcov_type *src, unsigned w
> #define GCOV_READ_COUNTER *(src++) * w
> #else
> #define GCOV_MERGE_EXTRA_ARGS
> #define GCOV_READ_COUNTER gcov_read_counter ()
> #endif
>
> __gcov_merge_add (gcov_type *counters, unsigned n_counters,
> GCOV_MERGE_EXTRA_ARGS)
> {
>
> for (; n_counters; counters++, n_counters--)
> {
> *counters += GCOV_READ_COUNTER ;
> }
>
> }
>
> thanks,
Personally I don't think the run time test of in_mem will cause any
issue. This is in profile dumping, why don't we care a few more cycle
heres? it won't pollute the profile.
If you really don't like that, we can use the above approach, or I can
hide the logic in gcov_read_counter(), i.e. overload
gcov_read_counter() in profile_tool. For that, I will need a new
global variable SRC and set it before calling the merge function.
I would prefer to keep weight in _gcov_merge_* argument list.
What do you think?
-Rong
>
> David
>
>>
>> I would suggest going with libgcov.h changes and clenaups first, with
>> interface changes next
>> and the gcov-tool is probably quite obvious at the end?
>> Do you think you can split the patch this way?
>>
>> Thanks and sorry for taking long to review. I should have more time again
>> now.
>> Honza
