On (25/02/16 15:57), Petr Spacek wrote: >On 19.2.2016 13:55, Petr Spacek wrote: >> Hello, >> >> Fix build with GCC 4.9+. >> >> GCC 4.9+ is too aggressive when optimizing functions with nonnull >> attributes. This removes most of asserts() in the plugin. >> GCC 6 adds warnings for these cases. >> >> We are disabling the unwanted condition pruning by adding >> -fno-delete-null-pointer-checks argument. >> BIND 9 did the same in its commit 603a78708343f063b44affb882ef93bb19a5142a. >> >> Additionally we silence warnings to prevent build failures when -Werror >> is used. >> >> https://bugzilla.redhat.com/show_bug.cgi?id=1307346 > >Updated version is attached. It contains less autotools magic because it >enables attribute nonnull only under Clang static analyzer and Coverity - as a >result we do not have to silence GCC warnings from -Wnonnull. > >Please review so I can fix build in Fedora 24. > >Thank you. > >-- >Petr^2 Spacek
>From 4732fe9f4e525c44b46e7ed0734ccaec94fba49e Mon Sep 17 00:00:00 2001 >From: Petr Spacek <pspa...@redhat.com> >Date: Fri, 19 Feb 2016 13:39:27 +0100 >Subject: [PATCH] Fix build with GCC 4.9+. > >GCC 4.9+ is too aggressive when optimizing functions with nonnull >attributes. This removes most of asserts() in the plugin. >GCC 6 adds warnings for these cases. > >We are disabling the unwanted condition pruning by adding >-fno-delete-null-pointer-checks argument. >BIND 9 did the same in its commit 603a78708343f063b44affb882ef93bb19a5142a. > >Additionally we enable nonnull attribute only when the build is running under >Clang static analyzer or Coverity. > >https://bugzilla.redhat.com/show_bug.cgi?id=1307346 >--- > configure.ac | 13 +++++++++++++ > src/util.h | 8 ++++++-- > 2 files changed, 19 insertions(+), 2 deletions(-) > >diff --git a/configure.ac b/configure.ac >index >a06708b1a5ee64bb64c80272c10ed1a35670c8d0..a0123ac0a62b5acd5238f028d8c42e83af4060db > 100644 >--- a/configure.ac >+++ b/configure.ac >@@ -39,6 +39,19 @@ AC_TRY_COMPILE([ > [CFLAGS="$SAVED_CFLAGS" > AC_MSG_RESULT([no])]) > >+# Check if build chain supports -fno-delete-null-pointer-checks >+# this flag avoids too agressive optimizations which would remove some asserts >+# BIND 9 did the same in its commit 603a78708343f063b44affb882ef93bb19a5142a >+AC_MSG_CHECKING([for -fno-delete-null-pointer-checks compiler flag]) >+SAVED_CFLAGS="$CFLAGS" >+CFLAGS="$CFLAGS -fno-delete-null-pointer-checks" >+AC_TRY_COMPILE([ >+ extern int fdef(void); >+],[], >+[AC_MSG_RESULT([yes])], >+[CFLAGS="$SAVED_CFLAGS" >+ AC_MSG_RESULT([no])]) >+ NACK. It failes with clang. configure:12982: checking for -fno-delete-null-pointer-checks compiler flag configure:12999: clang -c -O2 -g -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector-strong --param=ssp-buffer-size=4 -grecord-gcc-switches -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -m64 -mtune=generic -fvisibility=hidden -fno-delete-null-pointer-checks conftest.c >&5 clang-3.8: warning: optimization flag '-fno-delete-null-pointer-checks' is not supported clang-3.8: warning: argument unused during compilation: '-specs=/usr/lib/rpm/redhat/redhat-hardened-cc1' configure:12999: $? = 0 configure:13000: result: yes Reproducer: autoreconf -if && CC=clang ./configure && make LS -- Manage your subscription for the Freeipa-devel mailing list: https://www.redhat.com/mailman/listinfo/freeipa-devel Contribute to FreeIPA: http://www.freeipa.org/page/Contribute/Code
