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Commit 972c71a3 authored by Peter Oberparleiter's avatar Peter Oberparleiter Committed by Linus Torvalds
Browse files

gcov: fix documentation 



Commonly available versions of cp and tar don't work well with special
files created using seq_file.  Mention this problem in the gcov
documentation and update the helper script example to work around these
problems.

Signed-off-by: default avatarPeter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent b01e8dc3

Documentation/gcov.txt

+16 −9
Original line number Diff line number Diff line
@@ -188,13 +188,18 @@ Solution: Exclude affected source files from profiling by specifying 
          GCOV_PROFILE := n or GCOV_PROFILE_basename.o := n in the

          corresponding Makefile.



Problem:  Files copied from sysfs appear empty or incomplete.

Cause:    Due to the way seq_file works, some tools such as cp or tar

          may not correctly copy files from sysfs.

Solution: Use 'cat' to read .gcda files and 'cp -d' to copy links.

          Alternatively use the mechanism shown in Appendix B.





Appendix A: gather_on_build.sh

==============================



Sample script to gather coverage meta files on the build machine

(see 6a):



#!/bin/bash



KSRC=$1
@@ -226,7 +231,7 @@ Appendix B: gather_on_test.sh 
Sample script to gather coverage data files on the test machine

(see 6b):



#!/bin/bash

#!/bin/bash -e



DEST=$1

GCDA=/sys/kernel/debug/gcov
@@ -236,11 +241,13 @@ if [ -z "$DEST" ] ; then 
  exit 1

fi



find $GCDA -name '*.gcno' -o -name '*.gcda' | tar cfz $DEST -T -

TEMPDIR=$(mktemp -d)

echo Collecting data..

find $GCDA -type d -exec mkdir -p $TEMPDIR/\{\} \;

find $GCDA -name '*.gcda' -exec sh -c 'cat < $0 > '$TEMPDIR'/$0' {} \;

find $GCDA -name '*.gcno' -exec sh -c 'cp -d $0 '$TEMPDIR'/$0' {} \;

tar czf $DEST -C $TEMPDIR sys

rm -rf $TEMPDIR



if [ $? -eq 0 ] ; then

echo "$DEST successfully created, copy to build system and unpack with:"

echo "  tar xfz $DEST"
 
else

  echo "Could not create file $DEST"

fi