f7941ceba3
Duplicated const specifiers are allowed by C99 and can easily happen in macros. Also, systemd's interal code will use them. Disable this warning, it doesn't seem useful.
108 lines
3.4 KiB
Plaintext
108 lines
3.4 KiB
Plaintext
dnl Check whether a particular compiler flag works with code provided,
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dnl disable it in CFLAGS if the check fails.
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AC_DEFUN([NM_COMPILER_WARNING], [
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CFLAGS_SAVED="$CFLAGS"
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CFLAGS="$CFLAGS -Werror -W$1"
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AC_MSG_CHECKING(whether -W$1 works)
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AC_COMPILE_IFELSE([AC_LANG_SOURCE([[]])], [
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AC_COMPILE_IFELSE([AC_LANG_SOURCE([[$2]])], [
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AC_MSG_RESULT(yes)
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CFLAGS="$CFLAGS_SAVED -W$1"
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],[
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AC_MSG_RESULT(no)
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CFLAGS="$CFLAGS_SAVED -Wno-$1"
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])
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],[
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AC_MSG_RESULT(not supported)
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CFLAGS="$CFLAGS_SAVED"
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])
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])
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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="$enableval",set_more_warnings=yes)
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AC_MSG_CHECKING(for more warnings)
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if test "$GCC" = "yes" -a "$set_more_warnings" != "no"; then
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AC_MSG_RESULT(yes)
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dnl This is enabled in clang by default, makes little sense,
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dnl and causes the build to abort with -Werror.
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CFLAGS_SAVED="$CFLAGS"
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CFLAGS="$CFLAGS -Qunused-arguments"
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AC_COMPILE_IFELSE([AC_LANG_SOURCE([])], [], CFLAGS="$CFLAGS_SAVED")
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unset CFLAGS_SAVED
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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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NM_COMPILER_WARNING([unknown-warning-option], [])
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CFLAGS_SAVED="$CFLAGS"
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CFLAGS_MORE_WARNINGS="-Wall -std=gnu89"
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if test "x$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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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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-Wno-duplicate-decl-specifier \
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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 -Wno-pragmas; 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="-Werror $CFLAGS_MORE_WARNINGS $(printf '%s' "$option" | sed 's/^-Wno-/-W/') $CFLAGS_SAVED"
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AC_MSG_CHECKING([whether compiler 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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CFLAGS="$CFLAGS_SAVED"
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unset CFLAGS_SAVED
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dnl Disable warnings triggered by known compiler problems
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dnl https://bugzilla.gnome.org/show_bug.cgi?id=745821
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NM_COMPILER_WARNING([unknown-attributes], [#include <glib.h>])
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dnl https://bugzilla.gnome.org/show_bug.cgi?id=744473
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NM_COMPILER_WARNING([typedef-redefinition], [#include <gio/gio.h>])
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dnl https://llvm.org/bugs/show_bug.cgi?id=21614
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NM_COMPILER_WARNING([array-bounds],
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[#include <string.h>]
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[void f () { strcmp ("something", "0"); }]
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)
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dnl https://llvm.org/bugs/show_bug.cgi?id=22949
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NM_COMPILER_WARNING([parentheses-equality],
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[#include <sys/wait.h>]
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[void f () { if (WIFCONTINUED(0)) return; }]
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)
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dnl systemd-dhcp's log_internal macro and our handle_warn are sometimes
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dnl used in void context,u sometimes in int. Makes clang unhappy.
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NM_COMPILER_WARNING([unused-value],
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[#define yolo ({ (666 + 666); })]
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[int f () { int i = yolo; yolo; return i; }]
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)
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CFLAGS="$CFLAGS_MORE_WARNINGS $CFLAGS"
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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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