Regarding __gcov_dump and __gcov_reset usage

Regarding __gcov_dump and __gcov_reset usage

[Gejoe Daniel]

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Hi team,

I did go through the online manual of gcc gcov  on __gcov_dump() and __gcov_reset() :
https://gcc.gnu.org/onlinedocs/gcc/Gcov-and-Optimization.html#Gcov-and-Optimization

I tried out using the functions in a sample program (sample-prog.c) that is attached here.

The steps followed were :

(1)  gcc -fprofile-arcs -ftest-coverage sample-prog.c 
(2)  ./a.out
(3)  gcov sample-prog.c

While running a.out, when I give character 'g', the __gcov_dump() must be invoked.
What I could observe is that first time __gcov_dump() is invoked , the sample-prog.gcda file gets created.
For the second time and then onwards, __gcov_dump() invocation (by giving 'g' character during the a.out run) doesn't happen.
This is concluded by looking at the time stamp of sample-prog.gcda file in the same folder. It was still having the same time stamp of first time invocation of __gcov_dump().

Another thing is  that, __gcov_reset() also doesn't appear to work. I tried giving the character 'r' during the run of the program but couldn't see the counters getting reset to 0 in the sample-prog.gcov file. The previous values of lines covered were there.

Let me know if my approach is correct or if I miss any information here.

Thanks,
Gejoe
 

[-- Attachment #2: sample-prog.c --]
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// sample-prog.c
#include <stdio.h>
#include <ctype.h>
#include <unistd.h>

extern void __gcov_reset(void);
extern void __gcov_flush(void);
extern void __gcov_dump( void);

int main()
{
    unsigned char c;
    int result;
    unsigned char data[]={127,49,255,255};
	c = '5';

	do {
   
		c = getchar();
		result = isalnum(c);
		printf("When %c is passed, return value is %d\n", c, result);

		if(c == 'g')
			__gcov_dump();
		else if(c == 'r')
			__gcov_reset();
		
	}while(c != 'c');
    
	return 0;
}

Re: Regarding __gcov_dump and __gcov_reset usage

[Gejoe Daniel]

Hi Martin,

The bug is created : https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100751
 Let me know if any more info is required.

Thanks,
Gejoe

From: Martin Li ka <mliska@suse.cz>
Sent: Mon, 24 May 2021 19:32:10
To: Gejoe Daniel <gejoed@rediffmail.com>, gcc@gcc.gnu.org, gcc-help@gcc.gnu.org
Subject: Re: Regarding __gcov_dump and __gcov_reset usage

On 5/24/21 1:44 PM, Gejoe Daniel via Gcc wrote:
> Adding gcc mailing list for the clarification.
>
> Thank you team ! 
>
> From: "Gejoe Daniel"<gejoed@rediffmail.com>;
> Sent: Mon, 24 May 2021 15:02:12
> To: "gcc-help@gcc.gnu.org";<gcc-help@gcc.gnu.org>;
> Subject: Re: Regarding __gcov_dump and __gcov_reset usage
>
> Hi team,
>
> Any info/reply ?
>
> Thanking you in advance,
> Gejoe
>
>
> From: "Gejoe Daniel"<gejoed@rediffmail.com>;
> Sent: Sun, 16 May 2021 17:37:46
> To: <gcc-help@gcc.gnu.org>;
> Subject: Regarding __gcov_dump and __gcov_reset usage
>
> Hi team,
>
> I did go through the online manual of gcc gcov  on __gcov_dump() and __gcov_reset() :
> https://gcc.gnu.org/onlinedocs/gcc/Gcov-and-Optimization.html#Gcov-and-Optimization
>
> I tried out using the functions in a sample program (sample-prog.c) that is attached here.
>
> The steps followed were :
>
> (1)  gcc -fprofile-arcs -ftest-coverage sample-prog.c 
> (2)  ./a.out
> (3)  gcov sample-prog.c
>
> While running a.out, when I give character 'g', the __gcov_dump() must be invoked.
> What I could observe is that first time __gcov_dump() is invoked , the sample-prog.gcda file gets created.
> For the second time and then onwards, __gcov_dump() invocation (by giving 'g' character during the a.out run) doesn't happen.
> This is concluded by looking at the time stamp of sample-prog.gcda file in the same folder. It was still having the same time stamp of first time invocation of __gcov_dump().
>
> Another thing is  that, __gcov_reset() also doesn't appear to work. I tried giving the character 'r' during the run of the program but couldn't see the counters getting reset to 0 in the sample-prog.gcov file. The previous values of lines covered were there.
>
> Let me know if my approach is correct or if I miss any information here.
>
> Thanks,
> Gejoe
>  
>

Hello.

Can you please create bug at: https://gcc.gnu.org/bugzilla/
Please upload there a test-case and series of commands executed and the expected result.

Thank you,
Martin

Re: Regarding __gcov_dump and __gcov_reset usage

[Gejoe Daniel]

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Hi team,

Any info/reply ?

Thanking you in advance,
Gejoe


From: "Gejoe Daniel"<gejoed@rediffmail.com>
Sent: Sun, 16 May 2021 17:37:46
To: <gcc-help@gcc.gnu.org>
Subject: Regarding __gcov_dump and __gcov_reset usage

Hi team,

I did go through the online manual of gcc gcov  on __gcov_dump() and __gcov_reset() :
https://gcc.gnu.org/onlinedocs/gcc/Gcov-and-Optimization.html#Gcov-and-Optimization

I tried out using the functions in a sample program (sample-prog.c) that is attached here.

The steps followed were :

(1)  gcc -fprofile-arcs -ftest-coverage sample-prog.c 
(2)  ./a.out
(3)  gcov sample-prog.c

While running a.out, when I give character 'g', the __gcov_dump() must be invoked.
What I could observe is that first time __gcov_dump() is invoked , the sample-prog.gcda file gets created.
For the second time and then onwards, __gcov_dump() invocation (by giving 'g' character during the a.out run) doesn't happen.
This is concluded by looking at the time stamp of sample-prog.gcda file in the same folder. It was still having the same time stamp of first time invocation of __gcov_dump().

Another thing is  that, __gcov_reset() also doesn't appear to work. I tried giving the character 'r' during the run of the program but couldn't see the counters getting reset to 0 in the sample-prog.gcov file. The previous values of lines covered were there.

Let me know if my approach is correct or if I miss any information here.

Thanks,
Gejoe
 

[-- Attachment #2: sample-prog.c --]
[-- Type: application/octet-stream, Size: 535 bytes --]

// sample-prog.c
#include <stdio.h>
#include <ctype.h>
#include <unistd.h>

extern void __gcov_reset(void);
extern void __gcov_flush(void);
extern void __gcov_dump( void);

int main()
{
    unsigned char c;
    int result;
    unsigned char data[]={127,49,255,255};
	c = '5';

	do {
   
		c = getchar();
		result = isalnum(c);
		printf("When %c is passed, return value is %d\n", c, result);

		if(c == 'g')
			__gcov_dump();
		else if(c == 'r')
			__gcov_reset();
		
	}while(c != 'c');
    
	return 0;
}