[m-rev.] for review: update stream line numbers when reporting statistics

[Julien Fischer]

On Sun, 4 Apr 2021, Zoltan Somogyi wrote:

> On Sun, 4 Apr 2021 00:54:10 +1100 (AEDT), Julien Fischer <jfischer at opturion.com> wrote:
>>   :- pragma foreign_proc("C#",
>> -    report_stats,
>> +    do_report_stats(Stream::in),
>>       [may_call_mercury, terminates],
>>   "
>> -    ML_report_standard_stats(io.mercury_stderr);
>> +    ML_report_standard_stats(Stream.F1);
>>   ").
>
> I don't know what the .F1 here accomplishes; it certainly deserves
> a comment.

Done. F1 is the field in the generated Java class that corresponds to
the first agument of output_stream functor.  (In the C grades it's a
notag type and we can get at the underlying file stream using a cast; in
the C# and Java grades we do not apply the notag optimisation so we need
to use a field access to retrieve the file stream.)

As a separate change, I'm planning to add some C# and Java methods for
manipulating file streams from C# and Java respectively, but that's a
separate change.

>>   :- pragma foreign_proc("Java",
>> -    report_stats,
>> +    do_report_stats(Stream::in),
>>       [may_call_mercury, terminates],
>>   "
>> -    ML_report_standard_stats(io.mercury_stderr);
>> +    ML_report_standard_stats((io.MR_TextOutputFile) Stream.F1);
>>   ").
>
> Likewise, and the cast deserves a comment too.

Done.

>> @@ -67,7 +67,7 @@
>>   #endif // MR_MPROF_PROFILE_MEMORY
>>
>>   void
>> -MR_report_standard_stats(FILE *fp)
>> +MR_report_standard_stats(FILE *fp, int *line_number)
>>   {
>>       int                 user_time_at_prev_stat;
>>       int                 real_time_at_prev_stat;
>> @@ -153,11 +153,13 @@ MR_report_standard_stats(FILE *fp)
>>           GC_get_bytes_since_gc() / 1024.0,
>>           GC_get_heap_size() / 1024.0
>>       );
>> +    (*line_number)++;
>
> I didn't check for a one-to-one correspondence between lines printed
> and increments of *line_number, but I expect you did.

I did.

> I presume that the reason why the Java and C# code for printing stats
> has no similar increments is that the output methods they invoke do
> the increment at each newline already.

Correct.

> If that is right, then the diff is otherwise fine. And thanks.

Thanks for the review.

Julien.