At 10/18/2011 01:04 AM, Eric Blake Write: > On 10/17/2011 11:03 AM, Eric Blake wrote: >> On 10/17/2011 10:17 AM, Alex Jia wrote: >>> Eric, >>> It's latest libvirt upstream, current commit id is commit 0a71c79. >>> >>> # rpm -q glibc >>> glibc-2.12-1.42.el6.x86_64 >>> >> >>> 430 if (strchr(toescape, *cur)) >> >>>>> CC libvirt_util_la-buf.lo >>>>> util/buf.c: In function 'virBufferEscape': >>>>> util/buf.c:430: warning: logical '&&' with non-zero constant will >>>>> always >>>>> evaluate as true [-Wlogical-op] >> >> Something's screwy. There's no && in that line, unless strchr() is a >> macro based on your particular compilation flags. I'm suspecting that >> this is a case of -D_FORTIFY_SOURCE going awry. I don't see how this >> could possibly be a libvirt issue; more likely, it is an issue with the >> choice of compiler flags you are using, coupled with an issue in the >> system headers causing the preprocessor to expand strchr() into >> something that tickles a spurious gcc warning. > > Just to make sure, could you show 'make V=1' output, so we know exactly > which compiler flags are in effect? > I can reproduce this problem, here is 'make V=1' output: ===================================================== make[3]: Entering directory `/root/rpmbuild/BUILD/libvirt-0.9.6/src' /bin/sh ../libtool --tag=CC --mode=compile gcc -std=gnu99 -DHAVE_CONFIG_H -I. -I.. -I../gnulib/lib -I../gnulib/lib -I../include -I../src/util -I../include -DIN_LIBVIRT -I/usr/include/libxml2 -Wall -W -Wformat-y2k -Wformat-security -Winit-self -Wmissing-include-dirs -Wunused -Wunknown-pragmas -Wstrict-aliasing -Wshadow -Wpointer-arith -Wbad-function-cast -Wcast-align -Wwrite-strings -Wlogical-op -Waggregate-return -Wstrict-prototypes -Wold-style-definition -Wmissing-prototypes -Wmissing-declarations -Wmissing-noreturn -Wmissing-format-attribute -Wredundant-decls -Wnested-externs -Winline -Winvalid-pch -Wvolatile-register-var -Wdisabled-optimization -Wbuiltin-macro-redefined -Wmudflap -Wpacked-bitfield-compat -Wsync-nand -Wattributes -Wcoverage-mismatch -Wmultichar -Wno-missing-field-initializers -Wno-sign-compare -Wframe-larger-than=4096 -Wp,-D_FORTIFY_SOURCE=2 -fstack-protector-all --param=ssp-buffer-size=4 -fexceptions -fasynchronous-unwind-tables -fdiagnostics-s how-option -funit-at-a-time -Werror -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=4 -m64 -mtune=generic -MT libvirt_util_la-buf.lo -MD -MP -MF .deps/libvirt_util_la-buf.Tpo -c -o libvirt_util_la-buf.lo `test -f 'util/buf.c' || echo './'`util/buf.c libtool: compile: gcc -std=gnu99 -DHAVE_CONFIG_H -I. -I.. -I../gnulib/lib -I../gnulib/lib -I../include -I../src/util -I../include -DIN_LIBVIRT -I/usr/include/libxml2 -Wall -W -Wformat-y2k -Wformat-security -Winit-self -Wmissing-include-dirs -Wunused -Wunknown-pragmas -Wstrict-aliasing -Wshadow -Wpointer-arith -Wbad-function-cast -Wcast-align -Wwrite-strings -Wlogical-op -Waggregate-return -Wstrict-prototypes -Wold-style-definition -Wmissing-prototypes -Wmissing-declarations -Wmissing-noreturn -Wmissing-format-attribute -Wredundant-decls -Wnested-externs -Winline -Winvalid-pch -Wvolatile-register-var -Wdisabled-optimization -Wbuiltin-macro-redefined -Wmudflap -Wpacked-bitfield-compat -Wsync-nand -Wattributes -Wcoverage-mismatch -Wmultichar -Wno-missing-field-initializers -Wno-sign-compare -Wframe-larger-than=4096 -Wp,-D_FORTIFY_SOURCE=2 -fstack-protector-all --param=ssp-buffer-size=4 -fexceptions -fasynchronous-unwind-tables -fdiagnostics-show-option -funit-at-a-time -Werror -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=4 -m64 -mtune=generic -MT libvirt_util_la-buf.lo -MD -MP -MF .deps/libvirt_util_la-buf.Tpo -c util/buf.c -fPIC -DPIC -o .libs/libvirt_util_la-buf.o cc1: warnings being treated as errors util/buf.c: In function 'virBufferEscape': util/buf.c:430: error: logical '&&' with non-zero constant will always evaluate as true [-Wlogical-op] make[3]: *** [libvirt_util_la-buf.lo] Error 1 ===================================================== If I remove -O2, I can build util/buf.c. I am still investigating this problem. Thanks Wen Congyang -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list