On 1/2/21 5:49 PM, Bruno Haible wrote:
The vast majority of -Wanalyzer* warnings that we have seen so far were false alarms [1].
I've had such bad luck with those warnings that I have not been much motivated to file GCC bug reports for them. I guess the warnings are helpful with low-quality code, but I think I've only found one bug with them in many months of using them on several GNU projects, as compared to a lot of false alarms. I'm almost tempted to disable them in Gnulib by default.
For diffutils I worked around the problem by installing the attached patch, which disables the warning in Gnulib code.
Without the attached patch I got the same warning that Jim got, when I used GCC 10.2.1 20201125 (Red Hat 10.2.1-9) x86-64. I got more warnings elsewhere in Gnulib when I used gcc (Ubuntu 10.2.0-13ubuntu1) 10.2.0 x86-64, but I'd rather not work around those bugs as we can just ask people to use --disable-gcc-warnings if their GCC is old.
From f88b033174c4fa816d3b146312820725c658f707 Mon Sep 17 00:00:00 2001 From: Paul Eggert <[email protected]> Date: Sat, 2 Jan 2021 19:07:53 -0800 Subject: [PATCH] maint: work around GCC -Wreturn-local-addr bug * configure.ac: Do not use -Wreturn-local-addr in Gnulib, to suppress a false alarm in vasnprintf.c. --- configure.ac | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/configure.ac b/configure.ac index ef01345..3b2195e 100644 --- a/configure.ac +++ b/configure.ac @@ -95,6 +95,10 @@ if test "$gl_gcc_warnings" = yes; then nw="$nw -Wsuggest-attribute=pure" nw="$nw -Wduplicated-branches" # Too many false alarms + # Avoid false alarm in lib/vasnprintf.c. + # https://lists.gnu.org/r/bug-gnulib/2021-01/msg00031.html + gl_WARN_ADD([-Wno-analyzer-null-argument]) + gl_WARN_ADD([-Wno-return-local-addr]) # avoid this false alarm: # careadlinkat.c: In function 'careadlinkat': # cc1: error: function may return address of local variable [-Werror=return-local-addr] -- 2.27.0
