Re: [libvirt] Non-zero constant warning on RHEL 6.1 with 0.9.7

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++ = '\\';