[ovs-dev] [PATCH v2] Makefile.am: Add clang static analysis support
Ben Pfaff
blp at ovn.org
Sun Jul 3 14:43:16 UTC 2016
On Sun, Jul 03, 2016 at 11:32:49AM +0000, Bodireddy, Bhanuprakash wrote:
> >-----Original Message-----
> >From: Ben Pfaff [mailto:blp at ovn.org]
> >Sent: Sunday, July 3, 2016 1:12 AM
> >To: Bodireddy, Bhanuprakash <bhanuprakash.bodireddy at intel.com>
> >Cc: dev at openvswitch.org
> >Subject: Re: [ovs-dev] [PATCH v2] Makefile.am: Add clang static analysis
> >support
> >
> >On Sat, Jul 02, 2016 at 10:02:37PM +0000, Bodireddy, Bhanuprakash wrote:
> >>
> >> >-----Original Message-----
> >> >From: Ben Pfaff [mailto:blp at ovn.org]
> >> >Sent: Saturday, July 2, 2016 9:31 PM
> >> >To: Bodireddy, Bhanuprakash <bhanuprakash.bodireddy at intel.com>
> >> >Cc: dev at openvswitch.org
> >> >Subject: Re: [ovs-dev] [PATCH v2] Makefile.am: Add clang static
> >> >analysis support
> >> >
> >> >On Sat, Jul 02, 2016 at 08:14:02PM +0000, Bodireddy, Bhanuprakash wrote:
> >> >> >-----Original Message-----
> >> >> >From: Ben Pfaff [mailto:blp at ovn.org]
> >> >> >Sent: Saturday, July 2, 2016 6:14 PM
> >> >> >To: Bodireddy, Bhanuprakash <bhanuprakash.bodireddy at intel.com>
> >> >> >Cc: dev at openvswitch.org
> >> >> >Subject: Re: [ovs-dev] [PATCH v2] Makefile.am: Add clang static
> >> >> >analysis support
> >> >> >
> >> >> >On Tue, Jun 28, 2016 at 05:09:13PM +0100, Bhanuprakash Bodireddy
> >wrote:
> >> >> >> Clang Static Analyzer is a source code analysis tool to find bugs.
> >> >> >> This patch adds make target to trigger static analysis using
> >> >> >> below
> >> >commands.
> >> >> >>
> >> >> >> ./boot.sh
> >> >> >> ./configure --with-dpdk(in case of DPDK datapath) make
> >> >> >> clang-analyze scan-view --host=<ip address> --port <PORT>
> >> >> >> $OVS_DIR>/clang-analyzer-results/yyyy-mm-dd-114251-1027-1>
> >> >> >> --allow-all-hosts
> >> >> >>
> >> >> >> Results can be viewed on browser: http://<ip address>:<PORT>/
> >> >> >>
> >> >> >> v1->v2:
> >> >> >> * Change the output directory to tests/clang-analyzer-results
> >> >> >> * Remove '-j' make option, This might potentially hang some system
> >> >> >> while spawning infinite jobs.
> >> >> >>
> >> >> >> Signed-off-by: Bhanuprakash Bodireddy
> >> >> >> <bhanuprakash.bodireddy at intel.com>
> >> >> >
> >> >> >I'd tend to write this a little differently, maybe like this:
> >> >> >
> >> >> >clang-analyze: clean
> >> >> > @which clang scan-build >/dev/null 2>&1 || \
> >> >> > (echo "Unable to find clang/scan-build, Install
> >> >> >clang,clang-analyzer packages"; exit 1)
> >> >> > @$(MKDIR_P) "$(srcdir)/tests/clang-analyzer-results"
> >> >> > @scan-build -o $(srcdir)/tests/clang-analyzer-results --use-
> >> >> >analyzer=/usr/bin/clang $(MAKE)
> >> >> >.PHONY: clang-analyze
> >> >>
> >> >> This is fine for me.
> >> >>
> >> >> >
> >> >> >But it doesn't work for me anyway. When I run it from a build
> >> >> >tree configured to use clang, I get the following:
> >> >> >
> >> >> > make all-recursive
> >> >> > make[2]: Entering directory '/home/blp/nicira/ovs/_clang'
> >> >> > Making all in datapath
> >> >> > make[3]: Entering directory '/home/blp/nicira/ovs/_clang/datapath'
> >> >> > make[4]: Entering directory '/home/blp/nicira/ovs/_clang/datapath'
> >> >> > make[4]: Leaving directory '/home/blp/nicira/ovs/_clang/datapath'
> >> >> > make[3]: Leaving directory '/home/blp/nicira/ovs/_clang/datapath'
> >> >> > make[3]: Entering directory '/home/blp/nicira/ovs/_clang'
> >> >> > CC lib/aes128.lo
> >> >> > gcc: error: unrecognized command line option '-Wthread-safety'
> >> >> > gcc: error: unrecognized command line option '-Qunused-arguments'
> >> >> > gcc: error: unrecognized command line option '-fno-caret-diagnostics'
> >> >> > Makefile:4179: recipe for target 'lib/aes128.lo' failed
> >> >> > make[3]: *** [lib/aes128.lo] Error 1
> >> >> > make[3]: Leaving directory '/home/blp/nicira/ovs/_clang'
> >> >> > Makefile:4831: recipe for target 'all-recursive' failed
> >> >> > make[2]: *** [all-recursive] Error 1
> >> >> > make[2]: Leaving directory '/home/blp/nicira/ovs/_clang'
> >> >> > Makefile:2749: recipe for target 'all' failed
> >> >> > make[1]: *** [all] Error 2
> >> >> > make[1]: Leaving directory '/home/blp/nicira/ovs/_clang'
> >> >> > scan-build: Removing directory
> >> >> >'/home/blp/nicira/ovs/tests/clang-analyzer-
> >> >> >results/2016-07-02-101251-14653-1' because it contains no reports.
> >> >> > scan-build: No bugs found.
> >> >> > Makefile:5845: recipe for target 'clang-analyze' failed
> >> >> > make: *** [clang-analyze] Error 1
> >> >> >
> >> >> >Alternatively, if I run it from a build tree configured to use
> >> >> >GCC, I get the
> >> >> >following:
> >> >> >
> >> >> > make all-recursive
> >> >> > make[2]: Entering directory '/home/blp/nicira/ovs/_build'
> >> >> > Making all in datapath
> >> >> > make[3]: Entering directory '/home/blp/nicira/ovs/_build/datapath'
> >> >> > make[4]: Entering directory '/home/blp/nicira/ovs/_build/datapath'
> >> >> > make[4]: Leaving directory '/home/blp/nicira/ovs/_build/datapath'
> >> >> > make[3]: Leaving directory '/home/blp/nicira/ovs/_build/datapath'
> >> >> > make[3]: Entering directory '/home/blp/nicira/ovs/_build'
> >> >> > CC lib/aes128.lo
> >> >> > CC lib/backtrace.lo
> >> >> > CC lib/bfd.lo
> >> >> > In file included from ../lib/bfd.h:24:0,
> >> >> > from ../lib/bfd.c:16:
> >> >> > ../lib/packets.h: In function 'eth_addr_invert':
> >> >> > ../lib/packets.h:237:5: error: 'for' loop initial declarations
> >> >> >are only allowed in
> >> >> >C99 or C11 mode
> >> >> > ../lib/packets.h:237:5: note: use option -std=c99, -std=gnu99,
> >> >> >-std=c11 or -
> >> >> >std=gnu11 to compile your code
> >> >>
> >> >> I have tested this on F22 and didn't see this issue. But when I
> >> >> tested it now
> >> >on Ubuntu 14.04 LTS I could see the issue you reported here.
> >> >> Adding CFLAGS="-std=gnu99" to make should fix this issue and I
> >> >> tested it now on Ubuntu 14.04
> >> >>
> >> >> Can you try the below patch and see if you can generate clang
> >> >> analysis
> >> >report properly this time?
> >> >
> >> >This change seems rather arbitrary. Why doesn't the analysis phase
> >> >use the C compiler flags that have already been found to be correct for
> >compilation?
> >>
> >> I tested the slightly tweaked patch updated below (added '--use-cc' flag) for
> >both clang and gcc.
> >> I would let the user specify the CFLAGS at the configuration phase especially
> >with gcc compiler on some distributions.
> >> What do you think of this approach?
> >>
> >> Clang:
> >> ./configure CC=clang --with-dpdk=$DPDK_BUILD make clang-analyze
> >>
> >> gcc:
> >> ./configure CC=gcc --with-dpdk=$DPDK_BUILD CFLAGS="-std=gnu99"
> >> make clang-analyze
> >>
> >> +clang-analyze: clean
> >> + @which clang scan-build >/dev/null 2>&1 || \
> >> + (echo "Unable to find clang/scan-build, Install clang,clang-analyzer
> >packages"; exit 1)
> >> + @$(MKDIR_P) "$(srcdir)/tests/clang-analyzer-results"
> >> + @scan-build -o $(srcdir)/tests/clang-analyzer-results
> >> +--use-cc=$(CC) --use-analyzer=/usr/bin/clang $(MAKE)
> >> +.PHONY: clang-analyze
> >
> >The point I'm making is that the configure process already chooses a correct
> >set of CFLAGS and already allows the user to override them,
>
> Completely Agree Ben, Using GCC 4.8.4 , the configure process in the default case
> (i) ./configure --with-dpdk=/root/dpdk-16.04/x86_64-native-linuxapp-gcc, sets 'CFLAGS= -g -O2' and 'CC' as below.
>
> $ cat Makefile | grep "^CFLAGS ="
> CFLAGS = -g -O2
>
> $ cat Makefile | grep "^CC ="
> CC = $(if $(C),env REAL_CC="gcc -std=gnu99" CHECK="$(SPARSE) -I $(top_srcdir)/include/sparse $(SPARSEFLAGS) $(SPARSE_EXTRA_INCLUDES) " cgcc $(CGCCFLAGS),gcc -std=gnu99)
>
> clang-analyze target in this case fails as below.
> $make clang-analyze
> (Omitted clean ouput here)
> scan-build: unrecognized option '-std=gnu99'
> make: *** [clang-analyze] Error 1
>
> To get around this error, when CFLAGS is overridden from cmdline as
> (ii) ./configure CC=gcc --with-dpdk=$DPDK_BUILD CFLAGS="-std=gnu99", sets 'CFLAGS = -std=gnu99' and 'CC' as below.
>
> $ cat Makefile | grep "^CFLAGS ="
> CFLAGS = -std=gnu99
>
> $ cat Makefile | grep "^CC ="
> CC = $(if $(C),env REAL_CC="gcc" CHECK="$(SPARSE) -I $(top_srcdir)/include/sparse $(SPARSEFLAGS) $(SPARSE_EXTRA_INCLUDES) " cgcc $(CGCCFLAGS),gcc)
>
> Clang-analyze target works perfectly in this case.
>
> > so why doesn't
> >the clang-analyzer invocation use them?
>
> Clang-analyzer picks the CFLAGS automatically when invoked, output snippet is pasted from case (ii).
>
> '/bin/bash ./libtool --tag=CC --mode=compile /usr/share/clang/scan-build/ccc-analyzer -DHAVE_CONFIG_H -I. -I ./include -I ./include -I ./lib -I ./lib -Wstrict-prototypes -Wall -Wextra -Wno-sign-compare -Wpointer-arith -Wformat-security -Wswitch-enum -Wunused-parameter -Wbad-function-cast -Wcast-align -Wmissing-prototypes -Wmissing-field-initializers -fno-strict-aliasing -mssse3 -I/root/dpdk-16.04/x86_64-native-linuxapp-gcc/include -D_FILE_OFFSET_BITS=64 -std=gnu99 -MT lib/dpif.lo -MD -MP -MF $depbase.Tpo -c -o lib/dpif.lo lib/dpif.c'
>
> I have also attached the configuration logs for case (i) and (ii). This was tested using GCC version 4.8.4 on Ubuntu 14.04
> In case (i), config log shows: checking for gcc option to accept ISO C99... -std=gnu99
> In case (ii), config log shows : checking for gcc option to accept ISO C99... none needed
>
> This isn't observed when using GCC version 5.3.1 on F22. Am I missing something?
GCC 5.x defaults to gnu11 mode, so no option is necessary there.
I really don't understand the point you're making. Post a new version,
if you have one, that works on common setups.
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