Re: [PATCH] perf config: Fix build with older toolchain.

[Arnaldo Carvalho de Melo <acme@kernel.org>]

Em Mon, Apr 04, 2016 at 10:07:39PM +0000, Vinson Lee escreveu:
> Fix build error on Ubuntu 12.04.5 with GCC 4.6.3.

>   CC       util/config.o
> util/config.c: In function ‘perf_buildid_config’:
> util/config.c:384:15: error: declaration of ‘dirname’ shadows a global declaration [-Werror=shadow]

Argh, I was catching these by building on rhel6, but I stopped doing so
since switching to using docker images to do test builds... but I had
none set up for ubuntu 12.04 or any other distro with such breakage in
the headers, not anymore:

[root@jouet ~]# docker run -v /home/acme/git:/git --privileged=true
--rm=true -t -i ubuntu:12.04 /bin/bash
Unable to find image 'ubuntu:12.04' locally
Trying to pull repository docker.io/library/ubuntu ... 12.04: Pulling
from library/ubuntu
e37bb777fc4e: Pull complete

which is indeed:

root@7d7625f390d3:/# cat /etc/os-release 
NAME="Ubuntu"
VERSION="12.04.5 LTS, Precise Pangolin"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu precise (12.04.5 LTS)"
VERSION_ID="12.04"
root@7d7625f390d3:/# 

And where I indeed can reproduce this error:

root@7d7625f390d3:/# make JOBS=1 -C /git/linux/tools/perf
O=/tmp/build/perf install-bin 2>&1 | tail
  CC       /tmp/build/perf/util/config.o
util/config.c: In function 'perf_buildid_config':
util/config.c:384:15: error: declaration of 'dirname' shadows a global
declaration [-Werror=shadow]
cc1: all warnings being treated as errors
mv: cannot stat `/tmp/build/perf/util/.config.o.tmp': No such file or
directory
make[3]: *** [/tmp/build/perf/util/config.o] Error 1
make[2]: *** [util] Error 2
make[1]: *** [/tmp/build/perf/libperf-in.o] Error 2
make: *** [install-bin] Error 2
make: Leaving directory `/git/linux/tools/perf'
root@7d7625f390d3:/#

Applying the patch, hopefully with this new distro in the set of build
test images we won't see such problems for a while :-)

- Arnaldo
 
> Fixes: 9cb5987c8227 ("perf config: Rework buildid_dir_command_config to perf_buildid_config")
> Signed-off-by: Vinson Lee <vlee@freedesktop.org>
> ---
>  tools/perf/util/config.c |    6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/tools/perf/util/config.c b/tools/perf/util/config.c
> index 5c20d783423b..a3d80a05e7a2 100644
> --- a/tools/perf/util/config.c
> +++ b/tools/perf/util/config.c
> @@ -381,11 +381,11 @@ static int perf_buildid_config(const char *var, const char *value)
>  {
>  	/* same dir for all commands */
>  	if (!strcmp(var, "buildid.dir")) {
> -		const char *dirname = perf_config_dirname(var, value);
> +		const char *v = perf_config_dirname(var, value);
>  
> -		if (!dirname)
> +		if (!v)
>  			return -1;
> -		strncpy(buildid_dir, dirname, MAXPATHLEN-1);
> +		strncpy(buildid_dir, v, MAXPATHLEN-1);
>  		buildid_dir[MAXPATHLEN-1] = '\0';
>  	}
>  
> -- 
> 1.7.9.5