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
Signed-off-by: default avatarPeter Oberparleiter <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent b01e8dc3
......@@ -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:
Sample script to gather coverage meta files on the build machine
(see 6a):
......@@ -226,7 +231,7 @@ Appendix B:
Sample script to gather coverage data files on the test machine
(see 6b):
#!/bin/bash -e
......@@ -236,11 +241,13 @@ if [ -z "$DEST" ] ; then
exit 1
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"
echo "Could not create file $DEST"
echo "$DEST successfully created, copy to build system and unpack with:"
echo " tar xfz $DEST"
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