Re: [google 4.7] fdo build for linux kernel (issue 6968046)

[Rong Xu <xur@google.com>]

On Wed, Dec 19, 2012 at 5:22 PM, Rong Xu <xur@google.com> wrote:
> On Wed, Dec 19, 2012 at 5:04 PM,  <davidxl@google.com> wrote:
>> The change in gcov-io.h is from a different patch.
>
> sorry. here is the patch for gcov-io.h:
>
> Index: gcov-io.h
> ===================================================================
> --- gcov-io.h   (revision 194562)
> +++ gcov-io.h   (working copy)
> @@ -781,8 +781,8 @@
>                                           unused) */
>
>    unsigned n_functions;                /* number of functions */
> -  const struct gcov_fn_info *const *functions; /* pointer to pointers
> -                                                 to function information  */
> +  const struct gcov_fn_info **functions; /* pointer to pointers
> +                                           to function information  */
>  };
>
>  /* Information about a single imported module.  */
> @@ -988,8 +988,7 @@
>  GCOV_LINKAGE void gcov_seek (gcov_position_t /*position*/) ATTRIBUTE_HIDDEN;
>  GCOV_LINKAGE void gcov_truncate (void) ATTRIBUTE_HIDDEN;
>  GCOV_LINKAGE gcov_unsigned_t gcov_string_length (const char *)
> ATTRIBUTE_HIDDEN;
> -GCOV_LINKAGE unsigned gcov_gcda_file_size (struct gcov_info *,
> -                                           struct gcov_summary *);
> +GCOV_LINKAGE unsigned gcov_gcda_file_size (struct gcov_info *);
>  #else
>  /* Available outside libgcov */
>  GCOV_LINKAGE void gcov_sync (gcov_position_t /*base*/,
>
>>
>> David
>>
>>
>> https://codereview.appspot.com/6968046/diff/1/gcc/gcov-io.c
>> File gcc/gcov-io.c (right):
>>
>> https://codereview.appspot.com/6968046/diff/1/gcc/gcov-io.c#newcode688
>> gcc/gcov-io.c:688:
>> Have you compared this with this impl:
>>
>> while (x)
>> {
>>    c++;
>>    x&=(x-1)
>> }
>> return c;
>>
>
> I did not try this pimplier version. I can do a test on the dump speed
> and report back.

This simpler version is about 2% slow in dumping the profiles (average
of 10 dumps). But this is not a big deal.
I'll use this this version.

-Rong

>
>> https://codereview.appspot.com/6968046/