gdbsupport/warning.m4

   1 dnl Autoconf configure script for GDB, the GNU debugger.
   2 dnl Copyright (C) 1995-2024 Free Software Foundation, Inc.
   3 dnl
   4 dnl This file is part of GDB.
   5 dnl
   6 dnl This program is free software; you can redistribute it and/or modify
   7 dnl it under the terms of the GNU General Public License as published by
   8 dnl the Free Software Foundation; either version 3 of the License, or
   9 dnl (at your option) any later version.
  10 dnl
  11 dnl This program is distributed in the hope that it will be useful,
  12 dnl but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 dnl GNU General Public License for more details.
  15 dnl
  16 dnl You should have received a copy of the GNU General Public License
  17 dnl along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18
  19 AC_DEFUN([AM_GDB_WARNINGS],[
  20 AC_ARG_ENABLE(werror,
  21   AS_HELP_STRING([--enable-werror], [treat compile warnings as errors]),
  22   [case "${enableval}" in
  23      yes | y) ERROR_ON_WARNING="yes" ;;
  24      no | n)  ERROR_ON_WARNING="no" ;;
  25      *) AC_MSG_ERROR(bad value ${enableval} for --enable-werror) ;;
  26    esac])
  27
  28 # Enable -Werror by default when using gcc.  Turn it off for releases.
  29 if test "${GCC}" = yes -a -z "${ERROR_ON_WARNING}" && $development; then
  30     ERROR_ON_WARNING=yes
  31 fi
  32
  33 WERROR_CFLAGS=""
  34 if test "${ERROR_ON_WARNING}" = yes ; then
  35     WERROR_CFLAGS="-Werror"
  36 fi
  37
  38 # The options we'll try to enable.
  39 build_warnings="-Wall -Wpointer-arith \
  40 -Wno-unused -Wunused-value -Wunused-variable -Wunused-function \
  41 -Wno-switch -Wno-char-subscripts \
  42 -Wempty-body -Wunused-but-set-parameter -Wunused-but-set-variable \
  43 -Wno-sign-compare -Wno-error=maybe-uninitialized \
  44 -Wno-mismatched-tags \
  45 -Wno-error=deprecated-register \
  46 -Wsuggest-override \
  47 -Wimplicit-fallthrough=5 \
  48 -Wduplicated-cond \
  49 -Wshadow=local \
  50 -Wdeprecated-copy \
  51 -Wdeprecated-copy-dtor \
  52 -Wredundant-move \
  53 -Wmissing-declarations \
  54 -Wstrict-null-sentinel \
  55 -Wno-vla-cxx-extension \
  56 "
  57
  58 # The -Wmissing-prototypes flag will be accepted by GCC, but results
  59 # in a warning being printed about the flag not being valid for C++,
  60 # this is something to do with using ccache, and argument ordering.
  61 if test "$GDB_COMPILER_TYPE" != gcc; then
  62   build_warnings="$build_warnings -Wmissing-prototypes"
  63 fi
  64
  65 case "${host}" in
  66   *-*-mingw32*)
  67     # Enable -Wno-format by default when using gcc on mingw since many
  68     # GCC versions complain about %I64.
  69     build_warnings="$build_warnings -Wno-format" ;;
  70   *-*-solaris*)
  71     # Solaris 11.4 <python2.7/ceval.h> uses #pragma no_inline that GCC
  72     # doesn't understand.
  73     build_warnings="$build_warnings -Wno-unknown-pragmas"
  74     # Solaris 11 <unistd.h> marks vfork deprecated.
  75     build_warnings="$build_warnings -Wno-deprecated-declarations" ;;
  76   *)
  77     # Note that gcc requires -Wformat for -Wformat-nonliteral to work,
  78     # but there's a special case for this below.
  79     build_warnings="$build_warnings -Wformat-nonliteral" ;;
  80 esac
  81
  82 AC_ARG_ENABLE(build-warnings,
  83 AS_HELP_STRING([--enable-build-warnings], [enable build-time compiler warnings if gcc is used]),
  84 [case "${enableval}" in
  85   yes)  ;;
  86   no)   build_warnings="-w";;
  87   ,*)   t=`echo "${enableval}" | sed -e "s/,/ /g"`
  88         build_warnings="${build_warnings} ${t}";;
  89   *,)   t=`echo "${enableval}" | sed -e "s/,/ /g"`
  90         build_warnings="${t} ${build_warnings}";;
  91   *)    build_warnings=`echo "${enableval}" | sed -e "s/,/ /g"`;;
  92 esac
  93 if test x"$silent" != x"yes" && test x"$build_warnings" != x""; then
  94   echo "Setting compiler warning flags = $build_warnings" 6>&1
  95 fi])dnl
  96 AC_ARG_ENABLE(gdb-build-warnings,
  97 AS_HELP_STRING([--enable-gdb-build-warnings], [enable GDB specific build-time compiler warnings if gcc is used]),
  98 [case "${enableval}" in
  99   yes)  ;;
 100   no)   build_warnings="-w";;
 101   ,*)   t=`echo "${enableval}" | sed -e "s/,/ /g"`
 102         build_warnings="${build_warnings} ${t}";;
 103   *,)   t=`echo "${enableval}" | sed -e "s/,/ /g"`
 104         build_warnings="${t} ${build_warnings}";;
 105   *)    build_warnings=`echo "${enableval}" | sed -e "s/,/ /g"`;;
 106 esac
 107 if test x"$silent" != x"yes" && test x"$build_warnings" != x""; then
 108   echo "Setting GDB specific compiler warning flags = $build_warnings" 6>&1
 109 fi])dnl
 110
 111 # The set of warnings supported by a C++ compiler is not the same as
 112 # of the C compiler.
 113 AC_LANG_PUSH([C++])
 114
 115 WARN_CFLAGS=""
 116 if test "x${build_warnings}" != x -a "x$GCC" = xyes
 117 then
 118     AC_MSG_CHECKING(compiler warning flags)
 119     # Separate out the -Werror flag as some files just cannot be
 120     # compiled with it enabled.
 121     for w in ${build_warnings}; do
 122         # GCC does not complain about -Wno-unknown-warning.  Invert
 123         # and test -Wunknown-warning instead.
 124         case $w in
 125         -Wno-*)
 126                 wtest=`echo $w | sed 's/-Wno-/-W/g'` ;;
 127         -Wformat-nonliteral)
 128                 # gcc requires -Wformat before -Wformat-nonliteral
 129                 # will work, so stick them together.
 130                 w="-Wformat $w"
 131                 wtest="$w"
 132                 ;;
 133         *)
 134                 wtest=$w ;;
 135         esac
 136
 137         case $w in
 138         -Werr*) WERROR_CFLAGS=-Werror ;;
 139         *)
 140             # Check whether GCC accepts it.
 141             saved_CFLAGS="$CFLAGS"
 142             CFLAGS="$CFLAGS -Werror $wtest"
 143             saved_CXXFLAGS="$CXXFLAGS"
 144             CXXFLAGS="$CXXFLAGS -Werror $wtest"
 145             if test "x$w" = "x-Wunused-variable"; then
 146               # Check for https://gcc.gnu.org/bugzilla/show_bug.cgi?id=38958,
 147               # fixed in GCC 4.9.  This test is derived from the gdb
 148               # source code that triggered this bug in GCC.
 149               AC_COMPILE_IFELSE(
 150                 [AC_LANG_PROGRAM(
 151                    [struct scoped_restore_base {};
 152                     struct scoped_restore_tmpl : public scoped_restore_base {
 153                       ~scoped_restore_tmpl() {}
 154                     };],
 155                    [const scoped_restore_base &b = scoped_restore_tmpl();]
 156                  )],
 157                 [WARN_CFLAGS="${WARN_CFLAGS} $w"],
 158                 []
 159               )
 160             else
 161               AC_COMPILE_IFELSE(
 162                 [AC_LANG_PROGRAM([], [])],
 163                 [WARN_CFLAGS="${WARN_CFLAGS} $w"],
 164                 []
 165               )
 166             fi
 167             CFLAGS="$saved_CFLAGS"
 168             CXXFLAGS="$saved_CXXFLAGS"
 169         esac
 170     done
 171     AC_MSG_RESULT(${WARN_CFLAGS} ${WERROR_CFLAGS})
 172 fi
 173 AC_SUBST(WARN_CFLAGS)
 174 AC_SUBST(WERROR_CFLAGS)
 175
 176 AC_LANG_POP([C++])
 177 ])