Hello Martin,

On 23/03/2022 13:19, Martin Liška wrote:
> On 3/23/22 10:34, Sebastian Huber wrote:
> 
> Hello.
> 
> Thanks for the patch. Note we're in stage4, so the patch can eventually go
> in in the next stage1.

ok, good.

> 
>> The gcov_profile_merge() already had code to deal with profile 
>> information
>> which had no counterpart to merge with.  For profile information from 
>> files
>> with no associated counterpart, the profile information is simply used 
>> as is
>> with the weighting transformation applied.  Make sure that 
>> gcov_profile_merge()
>> works with an empty target profile list.  Return the merged profile list.
> 
> Can you please provide a simple demo with a pair of profiles
> where I'll see what changes?

The background for this feature is that I would like to combine the gcov 
information obtained from several test executables. Each test executable 
will print something like this (log.txt):

*** BEGIN OF GCOV INFO ***

/home/EB/sebastian_h/src/lwip/b-xilinx_zynq_a9_qemu/init.gcda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...

*** END OF GCOV INFO ***

The attached script reads the log file and creates the *.gcda files 
using gcov-tool. Initially, the target files do not exist.

> 
>>
>> gcc/
>>     * gcov-tool.cc (gcov_profile_merge): Adjust return type.
>>     (profile_merge): Allow merging of directories which contain no 
>> profile
>>     files.
>>
>> libgcc/
>>     * libgcov-util.c (gcov_profile_merge): Return the list of merged
>>     profiles.  Accept empty target and source profile lists.
>> ---
>>   gcc/gcov-tool.cc      | 27 ++++++++++-----------------
>>   libgcc/libgcov-util.c | 15 +++++++++------
>>   2 files changed, 19 insertions(+), 23 deletions(-)
>>
>> diff --git a/gcc/gcov-tool.cc b/gcc/gcov-tool.cc
>> index f4e42ae763c..2e4083a664d 100644
>> --- a/gcc/gcov-tool.cc
>> +++ b/gcc/gcov-tool.cc
>> @@ -40,7 +40,8 @@ see the files COPYING3 and COPYING.RUNTIME 
>> respectively.  If not, see
>>   #endif
>>   #include <getopt.h>
>> -extern int gcov_profile_merge (struct gcov_info*, struct gcov_info*, 
>> int, int);
>> +extern struct gcov_info *gcov_profile_merge (struct gcov_info*,
>> +                         struct gcov_info*, int, int);
>>   extern int gcov_profile_overlap (struct gcov_info*, struct gcov_info*);
>>   extern int gcov_profile_normalize (struct gcov_info*, gcov_type);
>>   extern int gcov_profile_scale (struct gcov_info*, float, int, int);
>> @@ -141,26 +142,18 @@ profile_merge (const char *d1, const char *d2, 
>> const char *out, int w1, int w2)
>>   {
>>     struct gcov_info *d1_profile;
>>     struct gcov_info *d2_profile;
>> -  int ret;
>> +  struct gcov_info *merged_profile;
>>     d1_profile = gcov_read_profile_dir (d1, 0);
>> -  if (!d1_profile)
>> -    return 1;
>> -
>> -  if (d2)
>> -    {
>> -      d2_profile = gcov_read_profile_dir (d2, 0);
>> -      if (!d2_profile)
>> -        return 1;
>> +  d2_profile = gcov_read_profile_dir (d2, 0);
> 
> Is it fine calling 'gcov_read_profile_dir (d2, 0)' without 'if (d2)'?

Yes, the caller ensures that d1 and d2 are both provided:

   if (argc - optind != 2)
     merge_usage ();

   return profile_merge (argv[optind], argv[optind+1], output_dir, w1, w2);

Maybe we should provide a better error message, if the user doesn't 
provide two directories instead of the general usage message.

> 
>> -      /* The actual merge: we overwrite to d1_profile.  */
>> -      ret = gcov_profile_merge (d1_profile, d2_profile, w1, w2);
>> +  /* The actual merge: we overwrite to d1_profile.  */
>> +  merged_profile = gcov_profile_merge (d1_profile, d2_profile, w1, w2);
>> -      if (ret)
>> -        return ret;
>> -    }
>> -
>> -  gcov_output_files (out, d1_profile);
>> +  if (merged_profile)
>> +    gcov_output_files (out, merged_profile);
>> +  else if (verbose)
>> +    fnotice (stdout, "no profile files were merged\n");
>>     return 0;
>>   }
>> diff --git a/libgcc/libgcov-util.c b/libgcc/libgcov-util.c
>> index ba7fb924b53..e5496f4ade2 100644
>> --- a/libgcc/libgcov-util.c
>> +++ b/libgcc/libgcov-util.c
>> @@ -677,13 +677,13 @@ find_match_gcov_info (struct gcov_info **array, 
>> int size,
>>      Return 0 on success: without mismatch.
>>      Reutrn 1 on error.  */
> 
> Please adjust the function comment.

Oh, yes.

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