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* Should templates with multiple instantiations contribute to summaries in gcov?
@ 2022-08-03 16:03 Jørgen Kvalsvik
  2022-08-22 19:25 ` [PATCH] gcov: fix file and function summary information Martin Liška
  0 siblings, 1 reply; 4+ messages in thread
From: Jørgen Kvalsvik @ 2022-08-03 16:03 UTC (permalink / raw)
  To: gcc


I have this program:

#include <cstdio>

template<class T>
T add (T x, T y) {
     if (x > y)
         return x + y;
     else
         return x;
}

template<class T>
T sub (T x, T y) {
     if (x > y)
         return x - y;
     else
         return x;
}

int main() {
     int i1 = 10;
     int i2 = 12;

     double d1 = 10.0;
     double d2 = 12.0;

     auto x = add(i1, i2);
     auto y = add(d1, d2);
     auto z = sub(i2, i1);

     printf ("%d %f %d\n", x, y, z);
}

add() is instantiated for int, double, and sub() is only instantiated 
for int.

$ gcc -v
gcc version 12.0.1 20220426 (experimental) (GCC)
$ gcc --coverage demo.cc -o demo && ./demo
$ gcov -mfb demo
Function 'int sub<int>(int, int)'
Lines executed:75.00% of 4

Function 'double add<double>(double, double)'
No executable lines

Function 'int add<int>(int, int)'
No executable lines

Function 'main'
Lines executed:100.00% of 10

File 'demo.cc'
Lines executed:88.89% of 18
Branches executed:100.00% of 2
Taken at least once:50.00% of 2
Calls executed:100.00% of 4
Creating 'demo.cc.gcov'

Lines executed:88.89% of 18

So it reports lines and branches accurately for templates with a single 
instantiation, but nothing when there are multiple. When you look at the 
.gcov file however the branches are reported for all the instantiations:

double add<double>(double, double):
function double add<double>(double, double) called 1 returned 100% 
blocks executed 75%
         1:    4:T add (T x, T y) {
         1:    5:    if (x > y)
branch  0 taken 0% (fallthrough)
branch  1 taken 100%
     #####:    6:        return x + y;
         -:    7:    else
         1:    8:        return x;
         -:    9:}

Skimming gcov.cc I found accumulate_line_info. By applying this patch 
the file summary includes all instantiations:

diff --git a/gcc/gcov.cc b/gcc/gcov.cc
index 04bbc774eec..c0ee9d1cd3f 100644
--- a/gcc/gcov.cc
+++ b/gcc/gcov.cc
@@ -2952,7 +2952,7 @@ accumulate_line_counts (source_info *src)
            it2 != fn->lines.end (); it2++)
           {
             line_info *line = &(*it2);
-           accumulate_line_info (line, src, false);
+           accumulate_line_info (line, src, true);
           }
      }

File 'demo.cc'
Lines executed:84.62% of 26
Branches executed:100.00% of 6
Taken at least once:50.00% of 6
Calls executed:100.00% of 4
Creating 'demo.cc.gcov'

It doesn't fix the function summaries however:

Function 'int add<int>(int, int)'
No executable lines

Looking through the changelog it looks like this was introduced to work 
with destructors/C++ clones 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=48463

Is there a non-obvious downside to look into groups in order to have 
templates count towards file- and function summaries? Any subtle 
interactions at play? Is this a bug?

Thanks,
Jørgen

^ permalink raw reply	[flat|nested] 4+ messages in thread

* [PATCH] gcov: fix file and function summary information
  2022-08-03 16:03 Should templates with multiple instantiations contribute to summaries in gcov? Jørgen Kvalsvik
@ 2022-08-22 19:25 ` Martin Liška
  2022-08-24  7:12   ` Jørgen Kvalsvik
  0 siblings, 1 reply; 4+ messages in thread
From: Martin Liška @ 2022-08-22 19:25 UTC (permalink / raw)
  To: gcc-patches; +Cc: Jørgen Kvalsvik, GCC Development

Patch can bootstrap on x86_64-linux-gnu and survives regression tests.

Jorgen: Can you please test it before I'll install it?

Thanks,
Martin

gcc/ChangeLog:

	* gcov.cc (add_line_counts): Add group functions to coverage
	summary.
	(accumulate_line_counts): Similarly for files.

Co-Authored-By: Jørgen Kvalsvik <j@lambda.is>
---
 gcc/gcov.cc | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/gcc/gcov.cc b/gcc/gcov.cc
index 27be5ff0911..9cf1071166f 100644
--- a/gcc/gcov.cc
+++ b/gcc/gcov.cc
@@ -2694,6 +2694,13 @@ add_line_counts (coverage_info *coverage, function_info *fn)
 		{
 		  gcc_assert (lines[j] - fn->start_line < fn->lines.size ());
 		  line = &(fn->lines[lines[j] - fn->start_line]);
+		  if (coverage)
+		    {
+		      if (!line->exists)
+			coverage->lines++;
+		      if (!line->count && block->count)
+			coverage->lines_executed++;
+		    }
 		  line->exists = 1;
 		  if (!block->exceptional)
 		    {
@@ -2815,7 +2822,7 @@ accumulate_line_counts (source_info *src)
 	   it2 != fn->lines.end (); it2++)
 	  {
 	    line_info *line = &(*it2);
-	    accumulate_line_info (line, src, false);
+	    accumulate_line_info (line, src, true);
 	  }
     }
 
-- 
2.37.2


^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] gcov: fix file and function summary information
  2022-08-22 19:25 ` [PATCH] gcov: fix file and function summary information Martin Liška
@ 2022-08-24  7:12   ` Jørgen Kvalsvik
  2022-08-24  7:31     ` Martin Liška
  0 siblings, 1 reply; 4+ messages in thread
From: Jørgen Kvalsvik @ 2022-08-24  7:12 UTC (permalink / raw)
  To: Martin Liška, gcc-patches; +Cc: GCC Development


On 22/08/2022 21:25, Martin Liška wrote:
> Patch can bootstrap on x86_64-linux-gnu and survives regression tests.
> 
> Jorgen: Can you please test it before I'll install it?
> 
> Thanks,
> Martin
> 
> gcc/ChangeLog:
> 
> 	* gcov.cc (add_line_counts): Add group functions to coverage
> 	summary.
> 	(accumulate_line_counts): Similarly for files.
> 
> Co-Authored-By: Jørgen Kvalsvik <j@lambda.is>
> ---
>   gcc/gcov.cc | 9 ++++++++-
>   1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/gcc/gcov.cc b/gcc/gcov.cc
> index 27be5ff0911..9cf1071166f 100644
> --- a/gcc/gcov.cc
> +++ b/gcc/gcov.cc
> @@ -2694,6 +2694,13 @@ add_line_counts (coverage_info *coverage, function_info *fn)
>   		{
>   		  gcc_assert (lines[j] - fn->start_line < fn->lines.size ());
>   		  line = &(fn->lines[lines[j] - fn->start_line]);
> +		  if (coverage)
> +		    {
> +		      if (!line->exists)
> +			coverage->lines++;
> +		      if (!line->count && block->count)
> +			coverage->lines_executed++;
> +		    }
>   		  line->exists = 1;
>   		  if (!block->exceptional)
>   		    {
> @@ -2815,7 +2822,7 @@ accumulate_line_counts (source_info *src)
>   	   it2 != fn->lines.end (); it2++)
>   	  {
>   	    line_info *line = &(*it2);
> -	    accumulate_line_info (line, src, false);
> +	    accumulate_line_info (line, src, true);
>   	  }
>       }
>   

I tested it and get the file summary as expected:

File 'demo.cc'
Lines executed:84.62% of 26
Branches executed:100.00% of 6
Taken at least once:50.00% of 6
Calls executed:100.00% of 4
Creating 'demo.cc.gcov'

Thanks,
Jørgen

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] gcov: fix file and function summary information
  2022-08-24  7:12   ` Jørgen Kvalsvik
@ 2022-08-24  7:31     ` Martin Liška
  0 siblings, 0 replies; 4+ messages in thread
From: Martin Liška @ 2022-08-24  7:31 UTC (permalink / raw)
  To: Jørgen Kvalsvik, gcc-patches; +Cc: GCC Development

On 8/24/22 09:12, Jørgen Kvalsvik wrote:
> I tested it and get the file summary as expected:
> 
> File 'demo.cc'
> Lines executed:84.62% of 26
> Branches executed:100.00% of 6
> Taken at least once:50.00% of 6
> Calls executed:100.00% of 4
> Creating 'demo.cc.gcov'
> 
> Thanks,
> Jørgen

Great, I've just pushed that as revision r13-2166-g42301c02e458cd.

Cheers,
Martin

^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2022-08-24  7:31 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2022-08-03 16:03 Should templates with multiple instantiations contribute to summaries in gcov? Jørgen Kvalsvik
2022-08-22 19:25 ` [PATCH] gcov: fix file and function summary information Martin Liška
2022-08-24  7:12   ` Jørgen Kvalsvik
2022-08-24  7:31     ` Martin Liška

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