http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58602
Greg Banks <gbanks at sgi dot com> changed:
What |Removed |Added
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CC| |gbanks at sgi dot com
--- Comment #1 from Greg Banks <gbanks at sgi dot com> ---
This bug can affect users of ggcov (http://ggcov.sf.net), which reads
the .gcno files directly rather than running any gcc code. Usually the
problem is harmless, as ggcov complains and stops parsing because it
tries to read random leftover bytes as a gcov tag. However it's possible
that other subtle problems can creep in, like lines being double-counted.
The bug appears to have been introduced in this commit
http://gcc.gnu.org/git/?p=gcc.git;a=commit;h=8ab576411b46496e6baf77ba1aed1f38b6c818cd
which nine years ago (!) changed the actual code path taken from
an fopen("wb") to an open(O_RDWR|O_CREAT) plus an fdopen(). One
of the differences between those is that the old code had the side
effect of truncating an existing file, and the new code doesn't.
It looks like every version of gcc since 3.4 is affected.
