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   1 # manywarnings.m4 serial 13
   2 dnl Copyright (C) 2008-2018 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 dnl From Simon Josefsson
   8
   9 # gl_MANYWARN_COMPLEMENT(OUTVAR, LISTVAR, REMOVEVAR)
  10 # --------------------------------------------------
  11 # Copy LISTVAR to OUTVAR except for the entries in REMOVEVAR.
  12 # Elements separated by whitespace.  In set logic terms, the function
  13 # does OUTVAR = LISTVAR \ REMOVEVAR.
  14 AC_DEFUN([gl_MANYWARN_COMPLEMENT],
  15 [
  16   gl_warn_set=
  17   set x $2; shift
  18   for gl_warn_item
  19   do
  20     case " $3 " in
  21       *" $gl_warn_item "*)
  22         ;;
  23       *)
  24         gl_warn_set="$gl_warn_set $gl_warn_item"
  25         ;;
  26     esac
  27   done
  28   $1=$gl_warn_set
  29 ])
  30
  31 # gl_MANYWARN_ALL_GCC(VARIABLE)
  32 # -----------------------------
  33 # Add all documented GCC warning parameters to variable VARIABLE.
  34 # Note that you need to test them using gl_WARN_ADD if you want to
  35 # make sure your gcc understands it.
  36 #
  37 # The effects of this macro depend on the current language (_AC_LANG).
  38 AC_DEFUN([gl_MANYWARN_ALL_GCC],
  39 [_AC_LANG_DISPATCH([$0], _AC_LANG, $@)])
  40
  41 # Specialization for _AC_LANG = C.
  42 # Use of m4_defun rather than AC_DEFUN works around a bug in autoconf < 2.63b.
  43 m4_defun([gl_MANYWARN_ALL_GCC(C)],
  44 [
  45   AC_LANG_PUSH([C])
  46
  47   dnl First, check for some issues that only occur when combining multiple
  48   dnl gcc warning categories.
  49   AC_REQUIRE([AC_PROG_CC])
  50   if test -n "$GCC"; then
  51
  52     dnl Check if -W -Werror -Wno-missing-field-initializers is supported
  53     dnl with the current $CC $CFLAGS $CPPFLAGS.
  54     AC_MSG_CHECKING([whether -Wno-missing-field-initializers is supported])
  55     AC_CACHE_VAL([gl_cv_cc_nomfi_supported], [
  56       gl_save_CFLAGS="$CFLAGS"
  57       CFLAGS="$CFLAGS -W -Werror -Wno-missing-field-initializers"
  58       AC_COMPILE_IFELSE(
  59         [AC_LANG_PROGRAM([[]], [[]])],
  60         [gl_cv_cc_nomfi_supported=yes],
  61         [gl_cv_cc_nomfi_supported=no])
  62       CFLAGS="$gl_save_CFLAGS"])
  63     AC_MSG_RESULT([$gl_cv_cc_nomfi_supported])
  64
  65     if test "$gl_cv_cc_nomfi_supported" = yes; then
  66       dnl Now check whether -Wno-missing-field-initializers is needed
  67       dnl for the { 0, } construct.
  68       AC_MSG_CHECKING([whether -Wno-missing-field-initializers is needed])
  69       AC_CACHE_VAL([gl_cv_cc_nomfi_needed], [
  70         gl_save_CFLAGS="$CFLAGS"
  71         CFLAGS="$CFLAGS -W -Werror"
  72         AC_COMPILE_IFELSE(
  73           [AC_LANG_PROGRAM(
  74              [[int f (void)
  75                {
  76                  typedef struct { int a; int b; } s_t;
  77                  s_t s1 = { 0, };
  78                  return s1.b;
  79                }
  80              ]],
  81              [[]])],
  82           [gl_cv_cc_nomfi_needed=no],
  83           [gl_cv_cc_nomfi_needed=yes])
  84         CFLAGS="$gl_save_CFLAGS"
  85       ])
  86       AC_MSG_RESULT([$gl_cv_cc_nomfi_needed])
  87     fi
  88
  89     dnl Next, check if -Werror -Wuninitialized is useful with the
  90     dnl user's choice of $CFLAGS; some versions of gcc warn that it
  91     dnl has no effect if -O is not also used
  92     AC_MSG_CHECKING([whether -Wuninitialized is supported])
  93     AC_CACHE_VAL([gl_cv_cc_uninitialized_supported], [
  94       gl_save_CFLAGS="$CFLAGS"
  95       CFLAGS="$CFLAGS -Werror -Wuninitialized"
  96       AC_COMPILE_IFELSE(
  97         [AC_LANG_PROGRAM([[]], [[]])],
  98         [gl_cv_cc_uninitialized_supported=yes],
  99         [gl_cv_cc_uninitialized_supported=no])
 100       CFLAGS="$gl_save_CFLAGS"])
 101     AC_MSG_RESULT([$gl_cv_cc_uninitialized_supported])
 102
 103   fi
 104
 105   # List all gcc warning categories.
 106   # To compare this list to your installed GCC's, run this Bash command:
 107   #
 108   # comm -3 \
 109   #  <(sed -n 's/^  *\(-[^ ]*\) .*/\1/p' manywarnings.m4 | sort) \
 110   #  <(gcc --help=warnings | sed -n 's/^  \(-[^ ]*\) .*/\1/p' | sort |
 111   #      grep -v -x -F -f <(
 112   #         awk '/^[^#]/ {print $1}' ../build-aux/gcc-warning.spec))
 113
 114   gl_manywarn_set=
 115   for gl_manywarn_item in -fno-common \
 116     -W \
 117     -Wabi \
 118     -Waddress \
 119     -Waggressive-loop-optimizations \
 120     -Wall \
 121     -Wattributes \
 122     -Wbad-function-cast \
 123     -Wbool-compare \
 124     -Wbool-operation \
 125     -Wbuiltin-declaration-mismatch \
 126     -Wbuiltin-macro-redefined \
 127     -Wcast-align \
 128     -Wchar-subscripts \
 129     -Wchkp \
 130     -Wclobbered \
 131     -Wcomment \
 132     -Wcomments \
 133     -Wcoverage-mismatch \
 134     -Wcpp \
 135     -Wdangling-else \
 136     -Wdate-time \
 137     -Wdeprecated \
 138     -Wdeprecated-declarations \
 139     -Wdesignated-init \
 140     -Wdisabled-optimization \
 141     -Wdiscarded-array-qualifiers \
 142     -Wdiscarded-qualifiers \
 143     -Wdiv-by-zero \
 144     -Wdouble-promotion \
 145     -Wduplicated-branches \
 146     -Wduplicated-cond \
 147     -Wduplicate-decl-specifier \
 148     -Wempty-body \
 149     -Wendif-labels \
 150     -Wenum-compare \
 151     -Wexpansion-to-defined \
 152     -Wextra \
 153     -Wformat-contains-nul \
 154     -Wformat-extra-args \
 155     -Wformat-nonliteral \
 156     -Wformat-security \
 157     -Wformat-signedness \
 158     -Wformat-y2k \
 159     -Wformat-zero-length \
 160     -Wframe-address \
 161     -Wfree-nonheap-object \
 162     -Whsa \
 163     -Wignored-attributes \
 164     -Wignored-qualifiers \
 165     -Wimplicit \
 166     -Wimplicit-function-declaration \
 167     -Wimplicit-int \
 168     -Wincompatible-pointer-types \
 169     -Winit-self \
 170     -Winline \
 171     -Wint-conversion \
 172     -Wint-in-bool-context \
 173     -Wint-to-pointer-cast \
 174     -Winvalid-memory-model \
 175     -Winvalid-pch \
 176     -Wjump-misses-init \
 177     -Wlogical-not-parentheses \
 178     -Wlogical-op \
 179     -Wmain \
 180     -Wmaybe-uninitialized \
 181     -Wmemset-elt-size \
 182     -Wmemset-transposed-args \
 183     -Wmisleading-indentation \
 184     -Wmissing-braces \
 185     -Wmissing-declarations \
 186     -Wmissing-field-initializers \
 187     -Wmissing-include-dirs \
 188     -Wmissing-parameter-type \
 189     -Wmissing-prototypes \
 190     -Wmultichar \
 191     -Wnarrowing \
 192     -Wnested-externs \
 193     -Wnonnull \
 194     -Wnonnull-compare \
 195     -Wnull-dereference \
 196     -Wodr \
 197     -Wold-style-declaration \
 198     -Wold-style-definition \
 199     -Wopenmp-simd \
 200     -Woverflow \
 201     -Woverlength-strings \
 202     -Woverride-init \
 203     -Wpacked \
 204     -Wpacked-bitfield-compat \
 205     -Wparentheses \
 206     -Wpointer-arith \
 207     -Wpointer-compare \
 208     -Wpointer-sign \
 209     -Wpointer-to-int-cast \
 210     -Wpragmas \
 211     -Wpsabi \
 212     -Wrestrict \
 213     -Wreturn-local-addr \
 214     -Wreturn-type \
 215     -Wscalar-storage-order \
 216     -Wsequence-point \
 217     -Wshadow \
 218     -Wshift-count-negative \
 219     -Wshift-count-overflow \
 220     -Wshift-negative-value \
 221     -Wsizeof-array-argument \
 222     -Wsizeof-pointer-memaccess \
 223     -Wstack-protector \
 224     -Wstrict-aliasing \
 225     -Wstrict-overflow \
 226     -Wstrict-prototypes \
 227     -Wsuggest-attribute=const \
 228     -Wsuggest-attribute=format \
 229     -Wsuggest-attribute=noreturn \
 230     -Wsuggest-attribute=pure \
 231     -Wsuggest-final-methods \
 232     -Wsuggest-final-types \
 233     -Wswitch \
 234     -Wswitch-bool \
 235     -Wswitch-default \
 236     -Wswitch-unreachable \
 237     -Wsync-nand \
 238     -Wsystem-headers \
 239     -Wtautological-compare \
 240     -Wtrampolines \
 241     -Wtrigraphs \
 242     -Wtype-limits \
 243     -Wuninitialized \
 244     -Wunknown-pragmas \
 245     -Wunsafe-loop-optimizations \
 246     -Wunused \
 247     -Wunused-but-set-parameter \
 248     -Wunused-but-set-variable \
 249     -Wunused-function \
 250     -Wunused-label \
 251     -Wunused-local-typedefs \
 252     -Wunused-macros \
 253     -Wunused-parameter \
 254     -Wunused-result \
 255     -Wunused-value \
 256     -Wunused-variable \
 257     -Wvarargs \
 258     -Wvariadic-macros \
 259     -Wvector-operation-performance \
 260     -Wvla \
 261     -Wvolatile-register-var \
 262     -Wwrite-strings \
 263     \
 264     ; do
 265     gl_manywarn_set="$gl_manywarn_set $gl_manywarn_item"
 266   done
 267
 268   # gcc --help=warnings outputs an unusual form for these options; list
 269   # them here so that the above 'comm' command doesn't report a false match.
 270   # Would prefer "min (PTRDIFF_MAX, SIZE_MAX)", but it must be a literal.
 271   # Also, AC_COMPUTE_INT requires it to fit in a long; it is 2**63 on
 272   # the only platforms where it does not fit in a long, so make that
 273   # a special case.
 274   AC_MSG_CHECKING([max safe object size])
 275   AC_COMPUTE_INT([gl_alloc_max],
 276     [LONG_MAX < (PTRDIFF_MAX < (size_t) -1 ? PTRDIFF_MAX : (size_t) -1)
 277      ? -1
 278      : PTRDIFF_MAX < (size_t) -1 ? (long) PTRDIFF_MAX : (long) (size_t) -1],
 279     [[#include <limits.h>
 280       #include <stddef.h>
 281       #include <stdint.h>
 282     ]],
 283     [gl_alloc_max=2147483647])
 284   case $gl_alloc_max in
 285     -1) gl_alloc_max=9223372036854775807;;
 286   esac
 287   AC_MSG_RESULT([$gl_alloc_max])
 288   gl_manywarn_set="$gl_manywarn_set -Walloc-size-larger-than=$gl_alloc_max"
 289   gl_manywarn_set="$gl_manywarn_set -Warray-bounds=2"
 290   gl_manywarn_set="$gl_manywarn_set -Wformat-overflow=2"
 291   gl_manywarn_set="$gl_manywarn_set -Wformat-truncation=2"
 292   gl_manywarn_set="$gl_manywarn_set -Wimplicit-fallthrough=5"
 293   gl_manywarn_set="$gl_manywarn_set -Wnormalized=nfc"
 294   gl_manywarn_set="$gl_manywarn_set -Wshift-overflow=2"
 295   gl_manywarn_set="$gl_manywarn_set -Wstringop-overflow=2"
 296   gl_manywarn_set="$gl_manywarn_set -Wunused-const-variable=2"
 297   gl_manywarn_set="$gl_manywarn_set -Wvla-larger-than=4031"
 298
 299   # These are needed for older GCC versions.
 300   if test -n "$GCC"; then
 301     case `($CC --version) 2>/dev/null` in
 302       'gcc (GCC) '[[0-3]].* | \
 303       'gcc (GCC) '4.[[0-7]].*)
 304         gl_manywarn_set="$gl_manywarn_set -fdiagnostics-show-option"
 305         gl_manywarn_set="$gl_manywarn_set -funit-at-a-time"
 306           ;;
 307     esac
 308   fi
 309
 310   # Disable specific options as needed.
 311   if test "$gl_cv_cc_nomfi_needed" = yes; then
 312     gl_manywarn_set="$gl_manywarn_set -Wno-missing-field-initializers"
 313   fi
 314
 315   if test "$gl_cv_cc_uninitialized_supported" = no; then
 316     gl_manywarn_set="$gl_manywarn_set -Wno-uninitialized"
 317   fi
 318
 319   $1=$gl_manywarn_set
 320
 321   AC_LANG_POP([C])
 322 ])
 323
 324 # Specialization for _AC_LANG = C++.
 325 # Use of m4_defun rather than AC_DEFUN works around a bug in autoconf < 2.63b.
 326 m4_defun([gl_MANYWARN_ALL_GCC(C++)],
 327 [
 328   gl_MANYWARN_ALL_GCC_CXX_IMPL([$1])
 329 ])