[Bug rtl-optimization/20815] New: -fprofile-use barfs with "coverage mismatch for function '...' while reading counter 'arcs'."

[Bug rtl-optimization/20815] New: -fprofile-use barfs with "coverage mismatch for function '...' while reading counter 'arcs'."

[dank at kegel dot com]

This problem is present in at least gcc-3.4.[123], gcc-3.4-20050401, and
gcc-4.0-20050305.  I have not tested a later gcc-4.0 yet.

Create a test file pgo.cc:
 #include <iostream>
 namespace {
   void
   func() {
     std::cout << "In func" << std::endl;
   }
 }
 int main() { func(); } 

Compile it, run it, and recompile it as follows:
  i686-unknown-linux-gnu-g++  -fprofile-generate -o pgo pgo.cc 
  ./pgo
  i686-unknown-linux-gnu-g++  -fprofile-use -o pgo pgo.cc 

The -fprofile-use compilation fails with
pgo.cc: In function 'void<unnamed>::func()':
pgo.cc:6: error: coverage mismatch for function
'_ZN35_GLOBAL__N_pgo.cc_00000000_8B40D3D54funcEv' while reading counter 'arcs'.
pgo.cc:6: error: checksum is 5c057dbb instead of 3746c244

Commenting out the namespace makes the problem go away.
This keeps me from building some real apps with profile-driven optimization,
which may result in switching from gcc to icc for this app.

Thanks to Simon Baldwin for finding such a nice little test case for this.

-- 
           Summary: -fprofile-use barfs with "coverage mismatch for function
                    '...' while reading counter 'arcs'."
           Product: gcc
           Version: 4.0.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: rtl-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: dank at kegel dot com
                CC: gcc-bugs at gcc dot gnu dot org
GCC target triplet: i686-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20815

[Bug rtl-optimization/20815] -fprofile-use barfs with "coverage mismatch for function '...' while reading counter 'arcs'."

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-04-07 22:21 -------
I hate unnamed namespaces since we have to encode some uniqueness and they are still extern 
because of C++ rules.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20815

[Bug middle-end/20815] -fprofile-use barfs with "coverage mismatch for function '...' while reading counter 'arcs'."

[pinskia at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|rtl-optimization            |middle-end


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20815

[Bug middle-end/20815] -fprofile-use barfs with "coverage mismatch for function '...' while reading counter 'arcs'."

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-04-07 22:31 -------
The easy work around is set -frandom-seed=somenumber for both the generate and use.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20815

[Bug middle-end/20815] -fprofile-use barfs with "coverage mismatch for function '...' while reading counter 'arcs'."

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-04-07 22:48 -------
The only thing I can think of to fix this problem is figure out how to write/read the random seed out 
since right now it is defaults to be basing on time.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |hubicka at gcc dot gnu dot
                   |                            |org
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
           Keywords|                            |rejects-valid
   Last reconfirmed|0000-00-00 00:00:00         |2005-04-07 22:48:37
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20815

[Bug middle-end/20815] -fprofile-use barfs with "coverage mismatch for function '...' while reading counter 'arcs'."

[dank at kegel dot com]

------- Additional Comments From dank at kegel dot com  2005-04-08 00:03 -------
Aha.  So this is a duplicate of bug 9393, in essence?

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20815

[Bug middle-end/20815] -fprofile-use barfs with "coverage mismatch for function '...' while reading counter 'arcs'."

[dank at kegel dot com]

------- Additional Comments From dank at kegel dot com  2005-04-08 00:03 -------
Oh, ok, it's not *quite* a dup of 9393, since you could
save the seed in the output file from the first run.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20815

[Bug middle-end/20815] -fprofile-use barfs with "coverage mismatch for function '...' while reading counter 'arcs'."

[dank at kegel dot com]

------- Additional Comments From dank at kegel dot com  2005-04-08 04:17 -------
What value should be passed for that option?
Would the absolute pathnme of the source file do?

In case other people out there have as much trouble reading
TFM as I do, I should note that the gcc doc says
"-frandom-seed=string ...
    The string should be different for every file you compile."

Thus the suggestion in
http://lists.freebsd.org/pipermail/freebsd-current/2004-November/042627.html
of using the same string always for this option is probably a bad
idea.  


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20815

[Bug middle-end/20815] -fprofile-use barfs with "coverage mismatch for function '...' while reading counter 'arcs'."

[dank at kegel dot com]

------- Additional Comments From dank at kegel dot com  2005-04-08 16:38 -------
Or should the doc say also that the argument to 
-frandom-seed should be the same every time
anyone compiles the same file?  In that case,
the relative path of the file within the project
would be a better choice.  So when compiling 
  mozilla/main.c
you would give
  -frandomSeed=mozilla/main.c
right?

Don't know how much this matters.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20815

[Bug gcov/profile/20815] -fprofile-use barfs with "coverage mismatch for function '...' while reading counter 'arcs'."

[hubicka at ucw dot cz]

------- Additional Comments From hubicka at ucw dot cz  2005-05-18 22:22 -------
Subject: Re: [Bug gcov/profile/20815] -fprofile-use barfs with "coverage mismatch for function '...' while reading counter 'arcs'."

coverage_checksum_string already knows a bit about ignoring random seed
produced mess.  It looks like this needs to be extended somehow to
handle namespaces too...

Honza
> 
> 
> -- 
>            What    |Removed                     |Added
> ----------------------------------------------------------------------------
>           Component|middle-end                  |gcov/profile
> 
> 
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20815
> 
> ------- You are receiving this mail because: -------
> You are on the CC list for the bug, or are watching someone who is.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20815

[Bug gcov/profile/20815] -fprofile-use barfs with "coverage mismatch for function '...' while reading counter 'arcs'."

[hubicka at ucw dot cz]

------- Additional Comments From hubicka at ucw dot cz  2005-05-18 22:47 -------
Subject: Re: [Bug gcov/profile/20815] -fprofile-use barfs with "coverage mismatch for function '...' while reading counter 'arcs'."

> 
> ------- Additional Comments From hubicka at ucw dot cz  2005-05-18 22:22 -------
> Subject: Re: [Bug gcov/profile/20815] -fprofile-use barfs with "coverage mismatch for function '...' while reading counter 'arcs'."
> 
> coverage_checksum_string already knows a bit about ignoring random seed
> produced mess.  It looks like this needs to be extended somehow to
> handle namespaces too...

This seems to solve the missmatch.  Would it be possible to test it on
bigger testcase and if it works distile a testcase that don't use
file IO so it is more suitable for gcc regtesting?

Index: coverage.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/coverage.c,v
retrieving revision 1.6.2.12.2.12
diff -c -3 -p -r1.6.2.12.2.12 coverage.c
*** coverage.c	18 May 2005 07:37:31 -0000	1.6.2.12.2.12
--- coverage.c	18 May 2005 22:45:36 -0000
*************** coverage_checksum_string (unsigned chksu
*** 471,505 ****
       as the checksums are used only for sanity checking.  */
    for (i = 0; string[i]; i++)
      {
        if (!strncmp (string + i, "_GLOBAL__", 9))
! 	for (i = i + 9; string[i]; i++)
! 	  if (string[i]=='_')
! 	    {
! 	      int y;
! 	      unsigned seed;
! 	      int scan;
! 
! 	      for (y = 1; y < 9; y++)
! 		if (!(string[i + y] >= '0' && string[i + y] <= '9')
! 		    && !(string[i + y] >= 'A' && string[i + y] <= 'F'))
! 		  break;
! 	      if (y != 9 || string[i + 9] != '_')
! 		continue;
! 	      for (y = 10; y < 18; y++)
! 		if (!(string[i + y] >= '0' && string[i + y] <= '9')
! 		    && !(string[i + y] >= 'A' && string[i + y] <= 'F'))
! 		  break;
! 	      if (y != 18)
! 		continue;
! 	      scan = sscanf (string + i + 10, "%X", &seed);
! 	      gcc_assert (scan);
! 	      if (seed != crc32_string (0, flag_random_seed))
! 		continue;
! 	      string = dup = xstrdup (string);
! 	      for (y = 10; y < 18; y++)
! 		dup[i + y] = '0';
! 	      break;
! 	    }
        break;
      }
  
--- 471,511 ----
       as the checksums are used only for sanity checking.  */
    for (i = 0; string[i]; i++)
      {
+       int offset = 0;
+       if (!strncmp (string + i, "_GLOBAL__N_", 11))
+ 	offset = 11;
        if (!strncmp (string + i, "_GLOBAL__", 9))
! 	offset = 9;
! 
!       /* C++ namespaces do have scheme:
!          _GLOBAL__N_<filename>_<wrongmagicnumber>_<magicnumber>functionname
! 	 since filename might contain extra underscores there seems
! 	 to be no better chance then walk all possible offsets looking
! 	 for magicnuber.  */
!       if (offset)
!         for (;string[offset]; offset++)
! 	  for (i = i + offset; string[i]; i++)
! 	    if (string[i]=='_')
! 	      {
! 		int y;
! 
! 		for (y = 1; y < 9; y++)
! 		  if (!(string[i + y] >= '0' && string[i + y] <= '9')
! 		      && !(string[i + y] >= 'A' && string[i + y] <= 'F'))
! 		    break;
! 		if (y != 9 || string[i + 9] != '_')
! 		  continue;
! 		for (y = 10; y < 18; y++)
! 		  if (!(string[i + y] >= '0' && string[i + y] <= '9')
! 		      && !(string[i + y] >= 'A' && string[i + y] <= 'F'))
! 		    break;
! 		if (y != 18)
! 		  continue;
! 		if (!dup)
! 		  string = dup = xstrdup (string);
! 		for (y = 10; y < 18; y++)
! 		  dup[i + y] = '0';
! 	      }
        break;
      }
  


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20815