m4/manywarnings-c++.m4

   1 # manywarnings-c++.m4 serial 3
   2 dnl Copyright (C) 2008-2020 Free Software Foundation, Inc.
   3 dnl This file is free software; the Free Software Foundation
   4 dnl gives unlimited permission to copy and/or distribute it,
   5 dnl with or without modifications, as long as this notice is preserved.
   6
   7 # Implementation of the specialization of gl_MANYWARN_ALL_GCC
   8 # for _AC_LANG = C++.
   9 AC_DEFUN([gl_MANYWARN_ALL_GCC_CXX_IMPL],
  10 [
  11   AC_LANG_PUSH([C++])
  12
  13   dnl First, check for some issues that only occur when combining multiple
  14   dnl gcc warning categories.
  15   AC_REQUIRE([AC_PROG_CXX])
  16   if test -n "$GXX"; then
  17
  18     dnl Check if -W -Werror -Wno-missing-field-initializers is supported
  19     dnl with the current $CXX $CXXFLAGS $CPPFLAGS.
  20     AC_CACHE_CHECK([whether -Wno-missing-field-initializers is supported],
  21       [gl_cv_cxx_nomfi_supported],
  22       [gl_save_CXXFLAGS="$CXXFLAGS"
  23        CXXFLAGS="$CXXFLAGS -W -Werror -Wno-missing-field-initializers"
  24        AC_COMPILE_IFELSE(
  25          [AC_LANG_PROGRAM([[]], [[]])],
  26          [gl_cv_cxx_nomfi_supported=yes],
  27          [gl_cv_cxx_nomfi_supported=no])
  28        CXXFLAGS="$gl_save_CXXFLAGS"
  29       ])
  30
  31     if test "$gl_cv_cxx_nomfi_supported" = yes; then
  32       dnl Now check whether -Wno-missing-field-initializers is needed
  33       dnl for the { 0, } construct.
  34       AC_CACHE_CHECK([whether -Wno-missing-field-initializers is needed],
  35         [gl_cv_cxx_nomfi_needed],
  36         [gl_save_CXXFLAGS="$CXXFLAGS"
  37          CXXFLAGS="$CXXFLAGS -W -Werror"
  38          AC_COMPILE_IFELSE(
  39            [AC_LANG_PROGRAM(
  40               [[int f (void)
  41                 {
  42                   typedef struct { int a; int b; } s_t;
  43                   s_t s1 = { 0, };
  44                   return s1.b;
  45                 }
  46               ]],
  47               [[]])],
  48            [gl_cv_cxx_nomfi_needed=no],
  49            [gl_cv_cxx_nomfi_needed=yes])
  50          CXXFLAGS="$gl_save_CXXFLAGS"
  51         ])
  52     fi
  53
  54     dnl Next, check if -Werror -Wuninitialized is useful with the
  55     dnl user's choice of $CXXFLAGS; some versions of gcc warn that it
  56     dnl has no effect if -O is not also used
  57     AC_CACHE_CHECK([whether -Wuninitialized is supported],
  58       [gl_cv_cxx_uninitialized_supported],
  59       [gl_save_CXXFLAGS="$CXXFLAGS"
  60        CXXFLAGS="$CXXFLAGS -Werror -Wuninitialized"
  61        AC_COMPILE_IFELSE(
  62          [AC_LANG_PROGRAM([[]], [[]])],
  63          [gl_cv_cxx_uninitialized_supported=yes],
  64          [gl_cv_cxx_uninitialized_supported=no])
  65        CXXFLAGS="$gl_save_CXXFLAGS"
  66       ])
  67
  68   fi
  69
  70   # List all gcc warning categories.
  71   # To compare this list to your installed GCC's, run this Bash command:
  72   #
  73   # comm -3 \
  74   #  <(sed -n 's/^  *\(-[^ ]*\) .*/\1/p' manywarnings-c++.m4 | sort) \
  75   #  <(gcc --help=warnings | sed -n 's/^  \(-[^ ]*\) .*/\1/p' | sort |
  76   #      grep -v -x -f <(
  77   #         awk '/^[^#]/ {print $1}' ../build-aux/g++-warning.spec))
  78
  79   gl_manywarn_set=
  80   for gl_manywarn_item in \
  81     -W \
  82     -Wabi-tag \
  83     -Waddress \
  84     -Waggressive-loop-optimizations \
  85     -Wall \
  86     -Wattributes \
  87     -Wbool-compare \
  88     -Wbuiltin-macro-redefined \
  89     -Wcast-align \
  90     -Wchar-subscripts \
  91     -Wclobbered \
  92     -Wcomment \
  93     -Wcomments \
  94     -Wconditionally-supported \
  95     -Wconversion-null \
  96     -Wcoverage-mismatch \
  97     -Wcpp \
  98     -Wctor-dtor-privacy \
  99     -Wdate-time \
 100     -Wdelete-incomplete \
 101     -Wdelete-non-virtual-dtor \
 102     -Wdeprecated \
 103     -Wdeprecated-declarations \
 104     -Wdisabled-optimization \
 105     -Wdiv-by-zero \
 106     -Wdouble-promotion \
 107     -Weffc++ \
 108     -Wempty-body \
 109     -Wendif-labels \
 110     -Wenum-compare \
 111     -Wextra \
 112     -Wformat-contains-nul \
 113     -Wformat-extra-args \
 114     -Wformat-nonliteral \
 115     -Wformat-security \
 116     -Wformat-signedness \
 117     -Wformat-y2k \
 118     -Wformat-zero-length \
 119     -Wfree-nonheap-object \
 120     -Wignored-qualifiers \
 121     -Winherited-variadic-ctor \
 122     -Winit-self \
 123     -Winline \
 124     -Wint-to-pointer-cast \
 125     -Winvalid-memory-model \
 126     -Winvalid-offsetof \
 127     -Winvalid-pch \
 128     -Wliteral-suffix \
 129     -Wlogical-not-parentheses \
 130     -Wlogical-op \
 131     -Wmain \
 132     -Wmaybe-uninitialized \
 133     -Wmemset-transposed-args \
 134     -Wmissing-braces \
 135     -Wmissing-declarations \
 136     -Wmissing-field-initializers \
 137     -Wmissing-include-dirs \
 138     -Wmultichar \
 139     -Wnarrowing \
 140     -Wnoexcept \
 141     -Wnon-template-friend \
 142     -Wnon-virtual-dtor \
 143     -Wnonnull \
 144     -Wodr \
 145     -Wold-style-cast \
 146     -Wopenmp-simd \
 147     -Woverflow \
 148     -Woverlength-strings \
 149     -Woverloaded-virtual \
 150     -Wpacked \
 151     -Wpacked-bitfield-compat \
 152     -Wparentheses \
 153     -Wpmf-conversions \
 154     -Wpointer-arith \
 155     -Wpragmas \
 156     -Wreorder \
 157     -Wreturn-local-addr \
 158     -Wreturn-type \
 159     -Wsequence-point \
 160     -Wshadow \
 161     -Wshift-count-negative \
 162     -Wshift-count-overflow \
 163     -Wsign-promo \
 164     -Wsized-deallocation \
 165     -Wsizeof-array-argument \
 166     -Wsizeof-pointer-memaccess \
 167     -Wstack-protector \
 168     -Wstrict-aliasing \
 169     -Wstrict-null-sentinel \
 170     -Wstrict-overflow \
 171     -Wsuggest-attribute=const \
 172     -Wsuggest-attribute=format \
 173     -Wsuggest-attribute=noreturn \
 174     -Wsuggest-attribute=pure \
 175     -Wsuggest-final-methods \
 176     -Wsuggest-final-types \
 177     -Wsuggest-override \
 178     -Wswitch \
 179     -Wswitch-bool \
 180     -Wsync-nand \
 181     -Wsystem-headers \
 182     -Wtrampolines \
 183     -Wtrigraphs \
 184     -Wtype-limits \
 185     -Wuninitialized \
 186     -Wunknown-pragmas \
 187     -Wunsafe-loop-optimizations \
 188     -Wunused \
 189     -Wunused-but-set-parameter \
 190     -Wunused-but-set-variable \
 191     -Wunused-function \
 192     -Wunused-label \
 193     -Wunused-local-typedefs \
 194     -Wunused-macros \
 195     -Wunused-parameter \
 196     -Wunused-result \
 197     -Wunused-value \
 198     -Wunused-variable \
 199     -Wuseless-cast \
 200     -Wvarargs \
 201     -Wvariadic-macros \
 202     -Wvector-operation-performance \
 203     -Wvirtual-move-assign \
 204     -Wvla \
 205     -Wvolatile-register-var \
 206     -Wwrite-strings \
 207     -Wzero-as-null-pointer-constant \
 208     \
 209     ; do
 210     gl_manywarn_set="$gl_manywarn_set $gl_manywarn_item"
 211   done
 212
 213   # gcc --help=warnings outputs an unusual form for these options; list
 214   # them here so that the above 'comm' command doesn't report a false match.
 215   gl_manywarn_set="$gl_manywarn_set -Warray-bounds=2"
 216   gl_manywarn_set="$gl_manywarn_set -Wnormalized=nfc"
 217   gl_manywarn_set="$gl_manywarn_set -Wshift-overflow=2"
 218   gl_manywarn_set="$gl_manywarn_set -Wunused-const-variable=2"
 219
 220   # These are needed for older GCC versions.
 221   if test -n "$GXX"; then
 222     case `($CXX --version) 2>/dev/null` in
 223       'g++ (GCC) '[[0-3]].* | \
 224       'g++ (GCC) '4.[[0-7]].*)
 225         gl_manywarn_set="$gl_manywarn_set -fdiagnostics-show-option"
 226         gl_manywarn_set="$gl_manywarn_set -funit-at-a-time"
 227           ;;
 228     esac
 229   fi
 230
 231   # Disable specific options as needed.
 232   if test "$gl_cv_cxx_nomfi_needed" = yes; then
 233     gl_manywarn_set="$gl_manywarn_set -Wno-missing-field-initializers"
 234   fi
 235
 236   if test "$gl_cv_cxx_uninitialized_supported" = no; then
 237     gl_manywarn_set="$gl_manywarn_set -Wno-uninitialized"
 238   fi
 239
 240   $1=$gl_manywarn_set
 241
 242   AC_LANG_POP([C++])
 243 ])