gdbsupport/warning.m4

   1 dnl Autoconf configure script for GDB, the GNU debugger.
   2 dnl Copyright (C) 1995-2023 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=3 \
  48 -Wduplicated-cond \
  49 -Wshadow=local \
  50 -Wdeprecated-copy \
  51 -Wdeprecated-copy-dtor \
  52 -Wredundant-move \
  53 -Wmissing-declarations \
  54 -Wstrict-null-sentinel \
  55 "
  56
  57 # The -Wmissing-prototypes flag will be accepted by GCC, but results
  58 # in a warning being printed about the flag not being valid for C++,
  59 # this is something to do with using ccache, and argument ordering.
  60 if test "$GDB_COMPILER_TYPE" != gcc; then
  61   build_warnings="$build_warnings -Wmissing-prototypes"
  62 fi
  63
  64 case "${host}" in
  65   *-*-mingw32*)
  66     # Enable -Wno-format by default when using gcc on mingw since many
  67     # GCC versions complain about %I64.
  68     build_warnings="$build_warnings -Wno-format" ;;
  69   *-*-solaris*)
  70     # Solaris 11.4 <python2.7/ceval.h> uses #pragma no_inline that GCC
  71     # doesn't understand.
  72     build_warnings="$build_warnings -Wno-unknown-pragmas"
  73     # Solaris 11 <unistd.h> marks vfork deprecated.
  74     build_warnings="$build_warnings -Wno-deprecated-declarations" ;;
  75   *)
  76     # Note that gcc requires -Wformat for -Wformat-nonliteral to work,
  77     # but there's a special case for this below.
  78     build_warnings="$build_warnings -Wformat-nonliteral" ;;
  79 esac
  80
  81 AC_ARG_ENABLE(build-warnings,
  82 AS_HELP_STRING([--enable-build-warnings], [enable build-time compiler warnings if gcc is used]),
  83 [case "${enableval}" in
  84   yes)  ;;
  85   no)   build_warnings="-w";;
  86   ,*)   t=`echo "${enableval}" | sed -e "s/,/ /g"`
  87         build_warnings="${build_warnings} ${t}";;
  88   *,)   t=`echo "${enableval}" | sed -e "s/,/ /g"`
  89         build_warnings="${t} ${build_warnings}";;
  90   *)    build_warnings=`echo "${enableval}" | sed -e "s/,/ /g"`;;
  91 esac
  92 if test x"$silent" != x"yes" && test x"$build_warnings" != x""; then
  93   echo "Setting compiler warning flags = $build_warnings" 6>&1
  94 fi])dnl
  95 AC_ARG_ENABLE(gdb-build-warnings,
  96 AS_HELP_STRING([--enable-gdb-build-warnings], [enable GDB specific build-time compiler warnings if gcc is used]),
  97 [case "${enableval}" in
  98   yes)  ;;
  99   no)   build_warnings="-w";;
 100   ,*)   t=`echo "${enableval}" | sed -e "s/,/ /g"`
 101         build_warnings="${build_warnings} ${t}";;
 102   *,)   t=`echo "${enableval}" | sed -e "s/,/ /g"`
 103         build_warnings="${t} ${build_warnings}";;
 104   *)    build_warnings=`echo "${enableval}" | sed -e "s/,/ /g"`;;
 105 esac
 106 if test x"$silent" != x"yes" && test x"$build_warnings" != x""; then
 107   echo "Setting GDB specific compiler warning flags = $build_warnings" 6>&1
 108 fi])dnl
 109
 110 # The set of warnings supported by a C++ compiler is not the same as
 111 # of the C compiler.
 112 AC_LANG_PUSH([C++])
 113
 114 WARN_CFLAGS=""
 115 if test "x${build_warnings}" != x -a "x$GCC" = xyes
 116 then
 117     AC_MSG_CHECKING(compiler warning flags)
 118     # Separate out the -Werror flag as some files just cannot be
 119     # compiled with it enabled.
 120     for w in ${build_warnings}; do
 121         # GCC does not complain about -Wno-unknown-warning.  Invert
 122         # and test -Wunknown-warning instead.
 123         case $w in
 124         -Wno-*)
 125                 wtest=`echo $w | sed 's/-Wno-/-W/g'` ;;
 126         -Wformat-nonliteral)
 127                 # gcc requires -Wformat before -Wformat-nonliteral
 128                 # will work, so stick them together.
 129                 w="-Wformat $w"
 130                 wtest="$w"
 131                 ;;
 132         *)
 133                 wtest=$w ;;
 134         esac
 135
 136         case $w in
 137         -Werr*) WERROR_CFLAGS=-Werror ;;
 138         *)
 139             # Check whether GCC accepts it.
 140             saved_CFLAGS="$CFLAGS"
 141             CFLAGS="$CFLAGS -Werror $wtest"
 142             saved_CXXFLAGS="$CXXFLAGS"
 143             CXXFLAGS="$CXXFLAGS -Werror $wtest"
 144             if test "x$w" = "x-Wunused-variable"; then
 145               # Check for https://gcc.gnu.org/bugzilla/show_bug.cgi?id=38958,
 146               # fixed in GCC 4.9.  This test is derived from the gdb
 147               # source code that triggered this bug in GCC.
 148               AC_COMPILE_IFELSE(
 149                 [AC_LANG_PROGRAM(
 150                    [struct scoped_restore_base {};
 151                     struct scoped_restore_tmpl : public scoped_restore_base {
 152                       ~scoped_restore_tmpl() {}
 153                     };],
 154                    [const scoped_restore_base &b = scoped_restore_tmpl();]
 155                  )],
 156                 [WARN_CFLAGS="${WARN_CFLAGS} $w"],
 157                 []
 158               )
 159             else
 160               AC_COMPILE_IFELSE(
 161                 [AC_LANG_PROGRAM([], [])],
 162                 [WARN_CFLAGS="${WARN_CFLAGS} $w"],
 163                 []
 164               )
 165             fi
 166             CFLAGS="$saved_CFLAGS"
 167             CXXFLAGS="$saved_CXXFLAGS"
 168         esac
 169     done
 170     AC_MSG_RESULT(${WARN_CFLAGS} ${WERROR_CFLAGS})
 171 fi
 172 AC_SUBST(WARN_CFLAGS)
 173 AC_SUBST(WERROR_CFLAGS)
 174
 175 AC_LANG_POP([C++])
 176 ])