[Bug c++/12076] gcov misreports coverage of return statement [NVR]

[Bug c++/12076] gcov misreports coverage of return statement [NVR]

[reddy at pixar dot com]

------- Comment #12 from reddy at pixar dot com  2005-10-27 01:41 -------
Having code coverage emit a "-" instead of "#####" in this case sounds
appropriate and would certainly solve the problem for me.

Is there a way to workaround this issue by reorganizing code, or something
else, so that I can fool the NVR smarts into not getting invoked in this
particular case?


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reddy at pixar dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |reddy at pixar dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12076

[Bug c++/12076] gcov misreports coverage of return statement [NVR]

[jbuck at welsh-buck dot org]

------- Comment #13 from jbuck at welsh-buck dot org  2006-01-21 22:33 -------
Subject: Re:  gcov misreports coverage of return statement
        [NVR]

On Thu, 2005-10-27 at 01:41 +0000, reddy at pixar dot com wrote:
> 
> ------- Comment #12 from reddy at pixar dot com  2005-10-27 01:41 -------
> Having code coverage emit a "-" instead of "#####" in this case sounds
> appropriate and would certainly solve the problem for me.
> 
> Is there a way to workaround this issue by reorganizing code, or something
> else, so that I can fool the NVR smarts into not getting invoked in this
> particular case?

The -fno-elide-constructors flag helps; it forces explicit copy constructor
calls, and that seems to get rid of most of the bogons -- but apparently
not all of them -- I'll look further, but I think sometimes the
initializer for a base class gets optimized in a way that results in a
false ###### flagging.  Still, if you're having this trouble, start with
that flag.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12076

[Bug c++/12076] gcov misreports coverage of return statement [NRV]

[pinskia at gcc dot gnu dot org]

------- Comment #14 from pinskia at gcc dot gnu dot org  2007-05-04 02:34 -------
*** Bug 31810 has been marked as a duplicate of this bug. ***


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pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |echristo at apple dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12076

[Bug c++/12076] gcov misreports coverage of return statement [NRV]

[hubicka at gcc dot gnu dot org]

------- Comment #15 from hubicka at gcc dot gnu dot org  2007-05-06 15:31 -------
The problem with NRV transformation is that it removes the return statement
from default path and keeps it in the catch path making GCOV to properly output
it as unexecuted.  I tried to look into the NRV modify_expr withing return_expr
but it is not the place to find the proper locator, looks like NRV itself needs
to be updated.

Honza


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12076

[Bug c++/12076] gcov misreports coverage of return statement [NRV]

[jbuck at gcc dot gnu dot org]

------- Comment #16 from jbuck at gcc dot gnu dot org  2007-05-07 00:32 -------
The return statement, before the optimization, does two things; it causes a
copy constructor call, and it causes the function to return.  NVR eliminates
the copy constructor call, but the statement still returns.  At -O0, don't we
still hit a distinct return statement for the code at the given source line? 
The fact that there is also unexecuted code present that executes only if
exceptions are caught should not matter, because we mark a statement as covered
if any part of it executes.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12076

[Bug c++/12076] gcov misreports coverage of return statement [NRV]

[pinskia at gcc dot gnu dot org]

------- Comment #17 from pinskia at gcc dot gnu dot org  2010-01-08 17:46 -------
*** Bug 42660 has been marked as a duplicate of this bug. ***


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pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |pluto at agmk dot net


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12076

[Bug c++/12076] New: gcov misreports coverage of return statement

[r dot lichtenberger at icoserve dot com]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12076

           Summary: gcov misreports coverage of return statement
           Product: gcc
           Version: 3.2.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: r dot lichtenberger at icoserve dot com
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: i686-pc-linux-gnu
  GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu

I compiled & ran this little program:
#include <string>
#include <iostream>

std::string repeat(const std::string& p_str, unsigned int p_count)
{
    std::string result;
    for (unsigned int i=0;i<p_count;++i)
        result+=p_str;
    return result;
}

int main(void)
{
        std::cout << repeat("gnu", 20) << std::endl;

        return 0;
}

The line containing the return statement is marked as "not run", which cannot be:
                std::string repeat(const std::string& p_str, unsigned int p_count)
           1    {
           1        std::string result;
          21        for (unsigned int i=0;i<p_count;++i)
          20            result+=p_str;
      ######        return result;
                }

[Bug c++/12076] gcov misreports coverage of return statement [NVR]

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-07-25 01:43 -------
*** Bug 23052 has been marked as a duplicate of this bug. ***

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jbuck at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12076

[Bug c++/12076] gcov misreports coverage of return statement [NVR]

[jbuck at gcc dot gnu dot org]

------- Additional Comments From jbuck at gcc dot gnu dot org  2005-07-25 20:54 -------
It's OK if NVR uses the same location and emits no code, and if coverage
information reflects this.  The problem is that part of the coverage machinery
appears to "think" that there is unreached code on the line with the return
statement, so a "#####" is output rather than a "-".  Emitting a "-" rather
than a count would also be OK, and arguably correct if there is no real object
code corresponding to the source line.





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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12076