-Wno-format ignored in Ubuntu 14.04 release

[Richard Earnshaw]

lsb_release -rd
Description: Ubuntu 14.04.1 LTS
Release: 14.04

gcc --version
gcc (Ubuntu 4.8.2-19ubuntu1) 4.8.2
...

Trying to run a recent glibc testsuite (from glibc trunk) results in testsuite errors because the compiler is overriding the -Wno-format option on the command line. Running the compiler with -v shows that it is appending an additional -Wformat after the user option and that there is no obvious way to override this behaviour. This is a bug.

#include <stdio.h>

int f()
{
  int n;
  return scanf ("%llllld", &n);
}

The above testcase should compile when compiled with -Wall -Werror -Wno-format, but instead generates errors for the unrecognized format specifier (note that this is a deliberate part of the test).

gcc -v -Wall -Werror -Wno-format /tmp/test.c -c -o /tmp/test.o
Using built-in specs.
COLLECT_GCC=gcc
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu 4.8.2-19ubuntu1' --with-bugurl=file:///usr/share/doc/gcc-4.8/README.Bugs --enable-languages=c,c++,java,go,d,fortran,objc,obj-c++ --prefix=/usr --program-suffix=-4.8 --enable-shared --enable-linker-build-id --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.8 --libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --enable-gnu-unique-object --disable-libmudflap --enable-plugin --with-system-zlib --disable-browser-plugin --enable-java-awt=gtk --enable-gtk-cairo --with-java-home=/usr/lib/jvm/java-1.5.0-gcj-4.8-amd64/jre --enable-java-home --with-jvm-root-dir=/usr/lib/jvm/java-1.5.0-gcj-4.8-amd64 --with-jvm-jar-dir=/usr/lib/jvm-exports/java-1.5.0-gcj-4.8-amd64 --with-arch-directory=amd64 --with-ecj-jar=/usr/share/java/eclipse-ecj.jar --enable-objc-gc --enable-multiarch --disable-werror --with-arch-32=i686 --with-abi=m64 --with-multilib-list=m32,m64,mx32 --with-tune=generic --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu
Thread model: posix
gcc version 4.8.2 (Ubuntu 4.8.2-19ubuntu1)
COLLECT_GCC_OPTIONS='-v' '-Wall' '-Werror' '-Wformat=0' '-c' '-o' '/tmp/test.o' '-mtune=generic' '-march=x86-64'
 /usr/lib/gcc/x86_64-linux-gnu/4.8/cc1 -quiet -v -imultiarch x86_64-linux-gnu /tmp/test.c -quiet -dumpbase test.c -mtune=generic -march=x86-64 -auxbase-strip /tmp/test.o -Wall -Werror -Wformat=0 -version -fstack-protector -Wformat -Wformat-security -o /tmp/ccGaCxtC.s
GNU C (Ubuntu 4.8.2-19ubuntu1) version 4.8.2 (x86_64-linux-gnu)
        compiled by GNU C version 4.8.2, GMP version 5.1.3, MPFR version 3.1.2-p3, MPC version 1.0.1
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
ignoring nonexistent directory "/usr/local/include/x86_64-linux-gnu"
ignoring nonexistent directory "/usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../x86_64-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
 /usr/lib/gcc/x86_64-linux-gnu/4.8/include
 /usr/local/include
 /usr/lib/gcc/x86_64-linux-gnu/4.8/include-fixed
 /usr/include/x86_64-linux-gnu
 /usr/include
End of search list.
GNU C (Ubuntu 4.8.2-19ubuntu1) version 4.8.2 (x86_64-linux-gnu)
        compiled by GNU C version 4.8.2, GMP version 5.1.3, MPFR version 3.1.2-p3, MPC version 1.0.1
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: dc75e0628c9356affcec059d0c81cc01
/tmp/test.c: In function ‘f’:
/tmp/test.c:6:3: error: unknown conversion type character ‘l’ in format [-Werror=format=]
   return scanf ("%llllld", &n);
   ^
/tmp/test.c:6:3: error: too many arguments for format [-Werror=format-extra-args]
cc1: all warnings being treated as errors

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Steve Langasek (vorlon)]

Hello Richard, or anyone else affected,

Accepted gcc-4.8 into trusty-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/gcc-4.8/4.8.4-2ubuntu1~14.04 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, and change the tag from verification-needed to verification-done. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed. In either case, details of your testing will help us make a better decision.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance!

[Steve Beattie (sbeattie)]

This bug is a duplicate of bug 1317305, which has already been verified successfully. Marking this bug as verified as well.

[Launchpad Janitor (janitor)]

This bug was fixed in the package gcc-4.8 - 4.8.4-2ubuntu1~14.04

---------------
gcc-4.8 (4.8.4-2ubuntu1~14.04) trusty-proposed; urgency=medium

  * SRU LP: #1311866.
  * Fix PR tree-optimization/63341 (wrong code, rs6000).
  * Allow to turn off -Wformat using Wno-format. LP: #1401836.
  * Fix PR target/60693 (x86, ice on valid code). LP: #1378737.
  * Fix PR tree-optimization/61964 (wrong code). LP: #1347147.
  * Fix GCC miscompilation with boost::asio::io_service::work. LP: #1338693.
  * Fix PR target/61208 (POWER, wrong code). LP: #1322287.
  * Fix ABI incompatibility between POWER and Z HTM builtins and intrinsics.
    LP: #1320292.
  * Fix PR c++/61046 (ice on invalid code). LP: #1313102.
  * Fix wrong-code issue in the little endian vector API (ppc64el).
    LP: #1311128.
  * Fix PR tree-optimization/59358 (wrong code). LP: #1395019.
  * Fix ice on ARM32. LP: #1268893.
  * Don't apply the backport for PR61841 for trusty, causing link failures.
  * Fix wrong code for vector doubleword extract (POWER). LP: #1437467.

gcc-4.8 (4.8.4-2ubuntu1) vivid; urgency=medium

  * Merge with Debian; remaining changes:
    - Build from the upstream source.

gcc-4.8 (4.8.4-2) unstable; urgency=medium

  * Update to SVN 20150426 (r222448) from the gcc-4_8-branch.
    - Fix PR libstdc++/60966, PR c/61553, PR middle-end/63704,
      PR target/61413 (ARM), PR target/64358 (RS6000), PR target/64479 (SH),
      PR target/64409 (x86), PR rtl-optimization/64037, PR c++/64487,
      PR c++/64251, PR c++/64297, PR fortran/63733, PR fortran/64244,
      PR c/64766, PR target/64882, PR rtl-optimization/61058,
      PR middle-end/43631, PR tree-optimization/64563, PR target/64513,
      PR middle-end/57748, PR middle-end/57748, PR target/64795,
      PR fortran/64528, PR fortran/56867, PR fortran/57023, PR c/57653,
      PR tree-optimization/63844 (OpenMP), PR middle-end/64199 (ice on valid),
      PR tree-optimization/64493 (ice on valid), PR tree-optimization/64495
      (wrong code), PR tree-optimization/56273 (diagnostics),
      PR tree-optimization/59124 (diagnostic), PR tree-optimization/64277
      (diagnostic), PR lto/65015, PR target/65163 (SH), PR target/64113 (ALPHA,
      link failure), PR rtl-optimization/64557, PR rtl-optimization/63475
      (ALPHA, wrong code), PR rtl-optimization/63483 (ALPHA, wrong code),
      PR target/64452 (AVR), PR target/64387 (x86, ice on valid),
      PR target/64979 (wrong code), PR target/64580 (rs6000),
      PR fortran/63744 (rejects valid), PR lto/65193 (ice on valid),
      PR tree-optimization/61634 (ice on valid), PR target/65196 (AVR),
      PR tree-optimization/63593 (ice on valid),
      PR tree-optimization/65063 (wrong code), PR target/65286 (rs6000),
      PR 65138/target (rs6000), PR target/53988 (SH), PR target/59593 (ARM),
      PR target/64453 (ARM), PR middle-end/65409 (ice on valid),
      PR tree-optimization/65388, PR fortran/65024 (ice),
      PR fortran/60898 (ice on valid), PR fortran/61138, PR libgfortran/60956,
      PR libstdc++/65279, PR libstdc++/65543, PR target/65849, PR target/65456,
      PR target/65787, PR c++/65727, PR c++/65721, PR fortran/56674,
      PR fortran/58813, PR fortran/590...

[Steve Langasek (vorlon)]

The verification of the Stable Release Update for gcc-4.8 has completed successfully and the package has now been released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regressions.