On 23.08.2013 18:50, Frantisek Hrbata wrote: > On Fri, Aug 23, 2013 at 05:09:58PM +0200, Peter Oberparleiter wrote: >> On 23.08.2013 10:39, Frantisek Hrbata wrote: >>> Since also the gcov structures(gcov_info, gcov_fn_info, gcov_ctr_info) can >>> change between gcc releases, as shown in gcc 4.7, they cannot be defined in a >>> common header and need to be moved to a specific gcc implemention file. This >>> also requires to make the gcov_info structure opaque for the common code and to >>> introduce simple helpers for accessing data inside gcov_info. >> >> I've taken a similar approach in my version, although I stopped at isolating >> the code that handles the linked list. I like your version better since it's >> more consistent. > > :) I also have doubts with the list "abstraction", it isn't very nice. I tried > to keep the changes as simple as possible in the generic code. I'm not sayint it > is the right approach, but your design is pretty good, so I had no urges to > change it more deeper. I'm of course open to any suggestions. I'd say go for this approach while it works and consider a replacement when it becomes necessary (because only then do we know what the requirements will be). >>> diff --git a/kernel/gcov/gcc_3_4.c b/kernel/gcov/gcc_3_4.c >>> index ae5bb42..27bc88a 100644 >>> --- a/kernel/gcov/gcc_3_4.c >>> +++ b/kernel/gcov/gcc_3_4.c >>> @@ -21,6 +21,121 @@ >>> #include <linux/vmalloc.h> >>> #include "gcov.h" >>> >>> +#define GCOV_COUNTERS 5 >> >> The value for GCOV_COUNTERS has been changed with GCC 4.3. Before it was 5, >> starting with GCC 4.3 the value is 8. While this is not strictly necessary, I'm >> wondering if this should be added here to prevent any unwanted side-effects. > > Yes I was thinking about this two. My first idea was to use some define, maybe > in the Makefile during the gcc version check and set the number of counters > properly later based on this define. Something like > > #if GCOV_GCC_VERIONS >= 0430 > #define GCOV_COUNTERS 8 > #elif ... > > for the gcc_3_4.c implementation. > > But I'm not sure what the new counters are good for and if they are really > needed for the coverage info. This would require deeper understanding what > and how the types of counters are used. At this point a simply did not change the > value for the format before gcc 4.7, because each counter type has a tag and > this should be backward compatible. We only miss the new counters. Again this is > something that probably deserves more attention. Thanks for pointing this out! Starting with GCC 4.7 support, GCOV_COUNTERS will have a direct effect on the size of gcov_info, so an incorrect value will break the format code. The change I commented on was pre-4.7 code though, so its not that important there. On the other hand it could help to have a corresponding mechanism in place once GCOV_COUNTERS changes again. Maybe something like a macro to determine if GCC is below a certain level. Regards, Peter -- Peter Oberparleiter Linux on System z Development - IBM Germany -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html