fixes based on gcc 6.x warnings #4632

marcelhuberfoo · 2016-05-11T20:09:39Z

The changes in the files should be self explanatory.

But there's another warning I was not able to fix due to fairly complicated indirections and bit manipulations. Here is the compiler output:

In file included from ../../include/sys/spa.h:588:0,
                 from zdb.c:34:
zdb.c: In function ‘dump_object’:
../../include/sys/dmu.h:130:8: warning: array subscript is outside array bounds [-Warray-bounds]
  dmu_ot[(int)(ot)].ot_byteswap)
  ~~~~~~^~~~~~~~~~~
zdb.c:72:18: note: in expansion of macro ‘DMU_OT_BYTESWAP’
  dmu_ot_byteswap[DMU_OT_BYTESWAP(idx)].ob_name : "UNKNOWN")
                  ^~~~~~~~~~~~~~~
zdb.c:1931:26: note: in expansion of macro ‘ZDB_OT_NAME’
      asize, lsize, fill, ZDB_OT_NAME(doi.doi_type), aux);
                          ^~~~~~~~~~~
../../include/sys/dmu.h:130:8: warning: array subscript is outside array bounds [-Warray-bounds]
  dmu_ot[(int)(ot)].ot_byteswap)
  ~~~~~~^~~~~~~~~~~
zdb.c:72:18: note: in expansion of macro ‘DMU_OT_BYTESWAP’
  dmu_ot_byteswap[DMU_OT_BYTESWAP(idx)].ob_name : "UNKNOWN")
                  ^~~~~~~~~~~~~~~
zdb.c:1936:7: note: in expansion of macro ‘ZDB_OT_NAME’
       ZDB_OT_NAME(doi.doi_bonus_type));
       ^~~~~~~~~~~

hinted by gcc: ../../module/zfs/zio_inject.c: In function ‘zio_handle_io_delay’: ../../module/zfs/zio_inject.c:382:3: warning: this ‘if’ clause does not guard... [-Wmisleading-indentation] if (handler->zi_record.zi_freq != 0 && ^~ ../../module/zfs/zio_inject.c:384:4: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the ‘if’ continue; ^~~~~~~~

hinted by gcc: libzfs_import.c: In function ‘fix_paths’: libzfs_import.c:602:28: warning: self-comparison always evaluates to true [-Wtautological-compare] if (best->ne_num_labels == best->ne_num_labels && ^~

behlendorf · 2016-05-11T20:19:37Z

Nice finds! Thanks for opening the PR, both of these LGTM. As for the zdb issue that's going to take more investigation.

I regularly build under CentOS 6.x and have never noticed these warnings. What additional flags are you including? We may want to add them them to debug builds.

tuxoko · 2016-05-11T20:31:04Z

Wow, it use indent has a hint to find if without curly braces, that's a nice feature. It makes me want to go back to Arch to get the latest GCC.

marcelhuberfoo · 2016-05-12T07:24:04Z

@tuxoko yes, Arch is quite nice to having (bleeding) edge tools available 👍
@behlendorf I am using gcc 6.1.1-1 as packaged in ArchLinux. Here is the verbose output of the zio_inject.c compilation where you might find the built in settings of the compiler in use:

  CC       zio_inject.lo
Using built-in specs.
COLLECT_GCC=gcc
Target: x86_64-pc-linux-gnu
Configured with: /build/gcc-multilib/src/gcc/configure --prefix=/usr --libdir=/usr/lib --libexecdir=/usr/lib --mandir=/usr/share/man --infodir=/usr/share/info --with-bugurl=https://bugs.archlinux.org/ --enable-languages=c,c++,ada,fortran,go,lto,objc,obj-c++ --enable-shared --enable-threads=posix --enable-libmpx --with-system-zlib --with-isl --enable-__cxa_atexit --disable-libunwind-exceptions --enable-clocale=gnu --disable-libstdcxx-pch --disable-libssp --enable-gnu-unique-object --enable-linker-build-id --enable-lto --enable-plugin --enable-install-libiberty --with-linker-hash-style=gnu --enable-gnu-indirect-function --enable-multilib --disable-werror --enable-checking=release
Thread model: posix
gcc version 6.1.1 20160501 (GCC) 
COLLECT_GCC_OPTIONS='-D' 'HAVE_CONFIG_H' '-include' '../../zfs_config.h' '-I' '../../include' '-I' '../../lib/libspl/include' '-D' '_GNU_SOURCE' '-D' '__EXTENSIONS__' '-D' '_REENTRANT' '-D' '_POSIX_PTHREAD_SEMANTICS' '-D' '_FILE_OFFSET_BITS=64' '-D' '_LARGEFILE64_SOURCE' '-D' 'HAVE_LARGE_STACKS=1' '-D' 'TEXT_DOMAIN="zfs-linux-user"' '-D' 'LIBEXECDIR="/usr/lib/zfs-0.6.5.247.g04bc461"' '-D' 'RUNSTATEDIR="/usr/var/run"' '-D' 'SBINDIR="/usr/bin"' '-D' 'SYSCONFDIR="/etc"' '-D' '_FORTIFY_SOURCE=2' '-D' 'NDEBUG' '-Wall' '-Wstrict-prototypes' '-Wno-unused-but-set-variable' '-Wno-bool-compare' '-fno-strict-aliasing' '-Wframe-larger-than=1024' '-v' '-march=x86-64' '-mtune=generic' '-O2' '-pipe' '-fstack-protector-strong' '-MT' 'zio_inject.lo' '-MD' '-MP' '-MF' '.deps/zio_inject.Tpo' '-c' '-fPIC' '-D' 'PIC' '-o' '.libs/zio_inject.o'
 /usr/lib/gcc/x86_64-pc-linux-gnu/6.1.1/cc1 -quiet -v -I ../../include -I ../../lib/libspl/include -MD .libs/zio_inject.d -MF .deps/zio_inject.Tpo -MP -MT zio_inject.lo -D HAVE_CONFIG_H -D _GNU_SOURCE -D __EXTENSIONS__ -D _REENTRANT -D _POSIX_PTHREAD_SEMANTICS -D _FILE_OFFSET_BITS=64 -D _LARGEFILE64_SOURCE -D HAVE_LARGE_STACKS=1 -D TEXT_DOMAIN="zfs-linux-user" -D LIBEXECDIR="/usr/lib/zfs-0.6.5.247.g04bc461" -D RUNSTATEDIR="/usr/var/run" -D SBINDIR="/usr/bin" -D SYSCONFDIR="/etc" -D _FORTIFY_SOURCE=2 -D NDEBUG -D PIC -include ../../zfs_config.h ../../module/zfs/zio_inject.c -quiet -dumpbase zio_inject.c -march=x86-64 -mtune=generic -auxbase-strip .libs/zio_inject.o -O2 -Wall -Wstrict-prototypes -Wno-unused-but-set-variable -Wno-bool-compare -Wframe-larger-than=1024 -version -fno-strict-aliasing -fstack-protector-strong -fPIC -o - |
 as -v -I ../../include -I ../../lib/libspl/include --64 -o .libs/zio_inject.o
GNU assembler version 2.26.0 (x86_64-pc-linux-gnu) using BFD version (GNU Binutils) 2.26.0.20160501
GNU C11 (GCC) version 6.1.1 20160501 (x86_64-pc-linux-gnu)
    compiled by GNU C version 6.1.1 20160501, GMP version 6.1.0, MPFR version 3.1.4-p1, MPC version 1.0.3, isl version 0.15
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
ignoring nonexistent directory "/usr/lib/gcc/x86_64-pc-linux-gnu/6.1.1/../../../../x86_64-pc-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
 ../../include
 ../../lib/libspl/include
 /usr/lib/gcc/x86_64-pc-linux-gnu/6.1.1/include
 /usr/local/include
 /usr/lib/gcc/x86_64-pc-linux-gnu/6.1.1/include-fixed
 /usr/include
End of search list.
GNU C11 (GCC) version 6.1.1 20160501 (x86_64-pc-linux-gnu)
    compiled by GNU C version 6.1.1 20160501, GMP version 6.1.0, MPFR version 3.1.4-p1, MPC version 1.0.3, isl version 0.15
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: 2b52ee45146df7b1f5b2606d8e51eb15
../../module/zfs/zio_inject.c: In function ‘zio_handle_io_delay’:
../../module/zfs/zio_inject.c:382:3: warning: this ‘if’ clause does not guard... [-Wmisleading-indentation]
   if (handler->zi_record.zi_freq != 0 &&
   ^~
../../module/zfs/zio_inject.c:384:4: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the ‘if’
    continue;
    ^~~~~~~~
COMPILER_PATH=/usr/lib/gcc/x86_64-pc-linux-gnu/6.1.1/:/usr/lib/gcc/x86_64-pc-linux-gnu/6.1.1/:/usr/lib/gcc/x86_64-pc-linux-gnu/:/usr/lib/gcc/x86_64-pc-linux-gnu/6.1.1/:/usr/lib/gcc/x86_64-pc-linux-gnu/
LIBRARY_PATH=/usr/lib/gcc/x86_64-pc-linux-gnu/6.1.1/:/usr/lib/gcc/x86_64-pc-linux-gnu/6.1.1/../../../../lib/:/lib/../lib/:/usr/lib/../lib/:/usr/lib/gcc/x86_64-pc-linux-gnu/6.1.1/../../../:/lib/:/usr/lib/
COLLECT_GCC_OPTIONS='-D' 'HAVE_CONFIG_H' '-include' '../../zfs_config.h' '-I' '../../include' '-I' '../../lib/libspl/include' '-D' '_GNU_SOURCE' '-D' '__EXTENSIONS__' '-D' '_REENTRANT' '-D' '_POSIX_PTHREAD_SEMANTICS' '-D' '_FILE_OFFSET_BITS=64' '-D' '_LARGEFILE64_SOURCE' '-D' 'HAVE_LARGE_STACKS=1' '-D' 'TEXT_DOMAIN="zfs-linux-user"' '-D' 'LIBEXECDIR="/usr/lib/zfs-0.6.5.247.g04bc461"' '-D' 'RUNSTATEDIR="/usr/var/run"' '-D' 'SBINDIR="/usr/bin"' '-D' 'SYSCONFDIR="/etc"' '-D' '_FORTIFY_SOURCE=2' '-D' 'NDEBUG' '-Wall' '-Wstrict-prototypes' '-Wno-unused-but-set-variable' '-Wno-bool-compare' '-fno-strict-aliasing' '-Wframe-larger-than=1024' '-v' '-march=x86-64' '-mtune=generic' '-O2' '-pipe' '-fstack-protector-strong' '-MT' 'zio_inject.lo' '-MD' '-MP' '-MF' '.deps/zio_inject.Tpo' '-c' '-fPIC' '-D' 'PIC' '-o' '.libs/zio_inject.o'

Arch specific options in use are:

CPPFLAGS="-D_FORTIFY_SOURCE=2"
CFLAGS="-march=x86-64 -mtune=generic -O2 -pipe -fstack-protector-strong"
LDFLAGS="-Wl,-O1,--sort-common,--as-needed,-z,relro"

behlendorf · 2016-05-12T19:30:52Z

I'd like to apply 6028dcd now but defer 7f231f0. This code will be replaced entirely when openzfs/openzfs@97e8130 is ported which @tonyhutter is working on at the moment. @tuxoko can I added your signed off to 6028dcd?

tuxoko · 2016-05-12T20:00:16Z

Go ahead
On May 12, 2016 12:30 PM, "Brian Behlendorf" [email protected]
wrote:

I'd like to apply 6028dcd
6028dcd
now but defer 7f231f0
7f231f0.
This code will be replaced entirely when openzfs/master@97e8130
https://github.com/openzfs/master/commit/97e8130 is ported with
@tonyhutter https://github.com/tonyhutter is working on at the moment.
@tuxoko https://github.com/tuxoko can I added your signed off to 6028dcd
6028dcd
?

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#4632 (comment)

Fixes bug introduced in commit 7d90f569a. Hinted by gcc: libzfs_import.c: In function ‘fix_paths’: libzfs_import.c:602:28: warning: self-comparison always evaluates to true [-Wtautological-compare] if (best->ne_num_labels == best->ne_num_labels && Signed-off-by: Marcel Huber <[email protected]> Signed-off-by: Chunwei Chen <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Issue openzfs#4632

behlendorf · 2016-05-17T18:36:44Z

OK, I've merged both fixed from this PR rather than wait for the openzfs/openzfs@97e8130 port.

Fixes bug introduced in commit 7d90f569a. Hinted by gcc: libzfs_import.c: In function ‘fix_paths’: libzfs_import.c:602:28: warning: self-comparison always evaluates to true [-Wtautological-compare] if (best->ne_num_labels == best->ne_num_labels && Signed-off-by: Marcel Huber <[email protected]> Signed-off-by: Chunwei Chen <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Issue openzfs#4632

Fixed bug introduced in commit #c35b1882. Hinted by gcc: zio_inject.c: In function ‘zio_handle_io_delay’: zio_inject.c:382:3: warning: this ‘if’ clause does not guard... [-Wmisleading-indentation] if (handler->zi_record.zi_freq != 0 && ^~ zio_inject.c:384:4: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the ‘if’ continue; ^~~~~~~~ Signed-off-by: Marcel Huber <[email protected]> Signed-off-by: Chunwei Chen <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes openzfs#4632

Fixes bug introduced in commit 7d90f569a. Hinted by gcc: libzfs_import.c: In function ‘fix_paths’: libzfs_import.c:602:28: warning: self-comparison always evaluates to true [-Wtautological-compare] if (best->ne_num_labels == best->ne_num_labels && Signed-off-by: Marcel Huber <[email protected]> Signed-off-by: Chunwei Chen <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Issue openzfs#4632

marcelhuberfoo added 2 commits May 11, 2016 21:30

fixes bug introduced in commit #7d90f569

6028dcd

hinted by gcc: libzfs_import.c: In function ‘fix_paths’: libzfs_import.c:602:28: warning: self-comparison always evaluates to true [-Wtautological-compare] if (best->ne_num_labels == best->ne_num_labels && ^~

behlendorf closed this in 2587cd8 May 17, 2016

This was referenced May 20, 2016

gcc 6.1 warnings in zdb.c #4675

Closed

gcc 6.1 warning in libzfs_import.c #4674

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fixes based on gcc 6.x warnings #4632

fixes based on gcc 6.x warnings #4632

marcelhuberfoo commented May 11, 2016

behlendorf commented May 11, 2016

tuxoko commented May 11, 2016

marcelhuberfoo commented May 12, 2016

behlendorf commented May 12, 2016 •

edited

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tuxoko commented May 12, 2016

behlendorf commented May 17, 2016

fixes based on gcc 6.x warnings #4632

fixes based on gcc 6.x warnings #4632

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marcelhuberfoo commented May 11, 2016

behlendorf commented May 11, 2016

tuxoko commented May 11, 2016

marcelhuberfoo commented May 12, 2016

behlendorf commented May 12, 2016 • edited Loading

tuxoko commented May 12, 2016

behlendorf commented May 17, 2016

behlendorf commented May 12, 2016 •

edited

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