0462104317
Since GCC 4.4, gcc does not warn about unknown -Wno-* flags. At least, it does not warning unless another warning is raised as well (https://gcc.gnu.org/wiki/FAQ#wnowarning). We didn't notice up to now, because we only tested flags that GCC actually supports. Hack around this, by checking for the -W* counterpart instead.
56 lines
1.9 KiB
Plaintext
56 lines
1.9 KiB
Plaintext
AC_DEFUN([NM_COMPILER_WARNINGS],
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[AC_ARG_ENABLE(more-warnings,
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AS_HELP_STRING([--enable-more-warnings], [Possible values: no/yes/error]),
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set_more_warnings="$enableval",set_more_warnings=error)
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AC_MSG_CHECKING(for more warnings)
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if test "$GCC" = "yes" -a "$set_more_warnings" != "no"; then
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AC_MSG_RESULT(yes)
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CFLAGS_SAVED="$CFLAGS"
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CFLAGS_MORE_WARNINGS="-Wall -std=gnu89"
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dnl clang only warns about unknown warnings, unless
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dnl called with "-Werror=unknown-warning-option"
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dnl Test if the compiler supports that, and if it does
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dnl attach it to the CFLAGS.
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CFLAGS_EXTRA="-Werror=unknown-warning-option"
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CFLAGS="$CFLAGS_MORE_WARNINGS $CFLAGS_EXTRA $CFLAGS_SAVED"
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AC_TRY_COMPILE([], [],
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has_option=yes,
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has_option=no,)
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if test $has_option = no; then
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CFLAGS_EXTRA=
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fi
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unset has_option
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for option in -Wshadow -Wmissing-declarations -Wmissing-prototypes \
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-Wdeclaration-after-statement -Wformat-security \
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-Wfloat-equal -Wno-unused-parameter -Wno-sign-compare \
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-Wstrict-prototypes \
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-fno-strict-aliasing -Wno-unused-but-set-variable \
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-Wundef -Wimplicit-function-declaration \
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-Wpointer-arith -Winit-self \
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-Wmissing-include-dirs; do
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dnl GCC 4.4 does not warn when checking for -Wno-* flags (https://gcc.gnu.org/wiki/FAQ#wnowarning)
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CFLAGS="$CFLAGS_MORE_WARNINGS $CFLAGS_EXTRA $(printf '%s' "$option" | sed 's/^-Wno-/-W/') $CFLAGS_SAVED"
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AC_MSG_CHECKING([whether gcc understands $option])
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AC_TRY_COMPILE([], [],
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has_option=yes,
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has_option=no,)
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if test $has_option != no; then
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CFLAGS_MORE_WARNINGS="$CFLAGS_MORE_WARNINGS $option"
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fi
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AC_MSG_RESULT($has_option)
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unset has_option
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done
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unset option
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unset CFLAGS_EXTRA
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if test "x$set_more_warnings" = xerror; then
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CFLAGS_MORE_WARNINGS="$CFLAGS_MORE_WARNINGS -Werror"
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fi
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CFLAGS="$CFLAGS_MORE_WARNINGS $CFLAGS_SAVED"
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unset CFLAGS_SAVED
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else
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AC_MSG_RESULT(no)
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fi
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])
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