On Tue, Nov 15, 2011 at 06:34:27AM -0500, Stefan Berger wrote:
On 11/14/2011 10:36 PM, Eric Blake wrote:
On 11/14/2011 05:54 PM, Stefan Berger wrote:
On 11/11/2011 04:06 PM, Eric Blake wrote:
On 11/08/2011 11:46 PM, Justin Clift wrote:
Hi guys,
Just checking 0.9.7 on RHEL 6.1 x86_64. Noticed this when compiling with make -j 3:
CC libvirt_lxc-command.o util/buf.c: In function 'virBufferEscape': util/buf.c:469: warning: logical '&&' with non-zero constant will always evaluate as true [-Wlogical-op]
Obviously not fatal, but it figured someone might want to keep things warning free. :) This is a bug in gcc, although I'm not sure if anyone has raised a bug report against the gcc folks yet: https://www.redhat.com/archives/libvir-list/2011-October/msg00837.html
I'm open to suggestions on how to work around it; perhaps we just need to disable -Wlogical-op if glibc's headers are turning on the optimized strchr (is that -D_FORTIFY_SOURCE that does it?) :(
At any rate, I agree that your proposed patch skirts the issue by using strstr() instead of strchr(), so it would indeed do the trick (while under the hood, strstr() on a single-byte needle tends to defer to strchr() anyways). It feels kind of gross, without at least a comment explaining that we are working around a gcc bug in -Wlogical-op (and even better, a URL of the gcc bug report); but I'm inclined to ACK it if we can come up with an appropriate comment.
What about this here:
--- a/src/util/buf.c +++ b/src/util/buf.c @@ -466,7 +466,11 @@ virBufferEscape(virBufferPtr buf, const char *toescape, cur = str; out = escaped; while (*cur != 0) { - if (strchr(toescape, *cur)) + /* strchr work-around for gcc 4.3 & 4.4 bug with -Wlogical-op + * http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36513 + */ + char needle[2] = { *cur, 0 }; + if (strstr(toescape, needle)) *out++ = '\\';
I'm puzzelled that we need this change here, but we have 175 other uses of strchr without trouble $ grep strchr src/*/*.c | wc -l 174 Is the difference just that we're deferencing a char * for the second arg rather than using a constant value ? Would it suffice to do int c = *cur; if (strchr(toescape, c)) Regards, Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|