[libvirt] [libvirt-sandbox][PATCH 3/4] m4: sync macros with libvirt

The macros under the m4 directory are outdated a bit. When trying to compile with newer gcc I see some errors: make[4]: Entering directory '/home/zippy/work/libvirt/libvirt-sanbox.git/libvirt-sandbox' CC libvirt_sandbox_1_0_la-libvirt-sandbox-main.lo gcc: warning: switch '-Wmudflap' is no longer supported Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com&gt; --- m4/manywarnings.m4 | 217 ++++++++++++++++++++++++++++---------------- m4/virt-compile-warnings.m4 | 216 +++++++++++++++++++++++++++++++------------ m4/warnings.m4 | 82 +++++++++++++---- 3 files changed, 361 insertions(+), 154 deletions(-) diff --git a/m4/manywarnings.m4 b/m4/manywarnings.m4 index fd0e372..3e6dd21 100644 --- a/m4/manywarnings.m4 +++ b/m4/manywarnings.m4 @@ -1,5 +1,5 @@ -# manywarnings.m4 serial 3 -dnl Copyright (C) 2008-2012 Free Software Foundation, Inc. +# manywarnings.m4 serial 7 +dnl Copyright (C) 2008-2014 Free Software Foundation, Inc. dnl This file is free software; the Free Software Foundation dnl gives unlimited permission to copy and/or distribute it, dnl with or without modifications, as long as this notice is preserved. @@ -35,14 +35,12 @@ AC_DEFUN([gl_MANYWARN_COMPLEMENT], # make sure your gcc understands it. AC_DEFUN([gl_MANYWARN_ALL_GCC], [ - dnl First, check if -Wno-missing-field-initializers is needed. - dnl -Wmissing-field-initializers is implied by -W, but that issues - dnl warnings with GCC version before 4.7, for the common idiom - dnl of initializing types on the stack to zero, using { 0, } + dnl First, check for some issues that only occur when combining multiple + dnl gcc warning categories. AC_REQUIRE([AC_PROG_CC]) if test -n "$GCC"; then - dnl First, check -W -Werror -Wno-missing-field-initializers is supported + dnl Check if -W -Werror -Wno-missing-field-initializers is supported dnl with the current $CC $CFLAGS $CPPFLAGS. AC_MSG_CHECKING([whether -Wno-missing-field-initializers is supported]) AC_CACHE_VAL([gl_cv_cc_nomfi_supported], [ @@ -77,108 +75,171 @@ AC_DEFUN([gl_MANYWARN_ALL_GCC], ]) AC_MSG_RESULT([$gl_cv_cc_nomfi_needed]) fi + + dnl Next, check if -Werror -Wuninitialized is useful with the + dnl user's choice of $CFLAGS; some versions of gcc warn that it + dnl has no effect if -O is not also used + AC_MSG_CHECKING([whether -Wuninitialized is supported]) + AC_CACHE_VAL([gl_cv_cc_uninitialized_supported], [ + gl_save_CFLAGS="$CFLAGS" + CFLAGS="$CFLAGS -Werror -Wuninitialized" + AC_COMPILE_IFELSE( + [AC_LANG_PROGRAM([[]], [[]])], + [gl_cv_cc_uninitialized_supported=yes], + [gl_cv_cc_uninitialized_supported=no]) + CFLAGS="$gl_save_CFLAGS"]) + AC_MSG_RESULT([$gl_cv_cc_uninitialized_supported]) + fi + # List all gcc warning categories. + # To compare this list to your installed GCC's, run this Bash command: + # + # comm -3 \ + # <(sed -n 's/^ *\(-[^ ]*\) .*/\1/p' manywarnings.m4 | sort) \ + # <(gcc --help=warnings | sed -n 's/^ \(-[^ ]*\) .*/\1/p' | sort | + # grep -v -x -f <( + # awk '/^[^#]/ {print $1}' ../build-aux/gcc-warning.spec)) + gl_manywarn_set= for gl_manywarn_item in \ - -Wall \ -W \ - -Wformat-y2k \ - -Wformat-nonliteral \ - -Wformat-security \ - -Winit-self \ - -Wmissing-include-dirs \ - -Wswitch-default \ - -Wswitch-enum \ - -Wunused \ - -Wunknown-pragmas \ - -Wstrict-aliasing \ - -Wstrict-overflow \ - -Wsystem-headers \ - -Wfloat-equal \ - -Wtraditional \ - -Wtraditional-conversion \ - -Wdeclaration-after-statement \ - -Wundef \ - -Wshadow \ - -Wunsafe-loop-optimizations \ - -Wpointer-arith \ - -Wbad-function-cast \ - -Wc++-compat \ - -Wcast-qual \ - -Wcast-align \ - -Wwrite-strings \ - -Wconversion \ - -Wsign-conversion \ - -Wlogical-op \ - -Waggregate-return \ - -Wstrict-prototypes \ - -Wold-style-definition \ - -Wmissing-prototypes \ - -Wmissing-declarations \ - -Wmissing-noreturn \ - -Wmissing-format-attribute \ - -Wpacked \ - -Wpadded \ - -Wredundant-decls \ - -Wnested-externs \ - -Wunreachable-code \ - -Winline \ - -Winvalid-pch \ - -Wlong-long \ - -Wvla \ - -Wvolatile-register-var \ - -Wdisabled-optimization \ - -Wstack-protector \ - -Woverlength-strings \ - -Wbuiltin-macro-redefined \ - -Wmudflap \ - -Wpacked-bitfield-compat \ - -Wsync-nand \ - ; do - gl_manywarn_set="$gl_manywarn_set $gl_manywarn_item" - done - # The following are not documented in the manual but are included in - # output from gcc --help=warnings. - for gl_manywarn_item in \ - -Wattributes \ - -Wcoverage-mismatch \ - -Wmultichar \ - -Wunused-macros \ - ; do - gl_manywarn_set="$gl_manywarn_set $gl_manywarn_item" - done - # More warnings from gcc 4.6.2 --help=warnings. - for gl_manywarn_item in \ -Wabi \ + -Waddress \ + -Waggressive-loop-optimizations \ + -Wall \ + -Warray-bounds \ + -Wattributes \ + -Wbad-function-cast \ + -Wbuiltin-macro-redefined \ + -Wcast-align \ + -Wchar-subscripts \ + -Wclobbered \ + -Wcomment \ + -Wcomments \ + -Wcoverage-mismatch \ -Wcpp \ + -Wdate-time \ -Wdeprecated \ -Wdeprecated-declarations \ + -Wdisabled-optimization \ -Wdiv-by-zero \ -Wdouble-promotion \ + -Wempty-body \ -Wendif-labels \ + -Wenum-compare \ -Wextra \ -Wformat-contains-nul \ -Wformat-extra-args \ + -Wformat-nonliteral \ + -Wformat-security \ + -Wformat-y2k \ -Wformat-zero-length \ - -Wformat=2 \ + -Wfree-nonheap-object \ + -Wignored-qualifiers \ + -Wimplicit \ + -Wimplicit-function-declaration \ + -Wimplicit-int \ + -Winit-self \ + -Winline \ + -Wint-to-pointer-cast \ + -Winvalid-memory-model \ + -Winvalid-pch \ + -Wjump-misses-init \ + -Wlogical-op \ + -Wmain \ + -Wmaybe-uninitialized \ + -Wmissing-braces \ + -Wmissing-declarations \ + -Wmissing-field-initializers \ + -Wmissing-include-dirs \ + -Wmissing-parameter-type \ + -Wmissing-prototypes \ -Wmultichar \ - -Wnormalized=nfc \ + -Wnarrowing \ + -Wnested-externs \ + -Wnonnull \ + -Wold-style-declaration \ + -Wold-style-definition \ + -Wopenmp-simd \ -Woverflow \ + -Woverlength-strings \ + -Woverride-init \ + -Wpacked \ + -Wpacked-bitfield-compat \ + -Wparentheses \ + -Wpointer-arith \ + -Wpointer-sign \ -Wpointer-to-int-cast \ -Wpragmas \ + -Wreturn-local-addr \ + -Wreturn-type \ + -Wsequence-point \ + -Wshadow \ + -Wsizeof-pointer-memaccess \ + -Wstack-protector \ + -Wstrict-aliasing \ + -Wstrict-overflow \ + -Wstrict-prototypes \ -Wsuggest-attribute=const \ + -Wsuggest-attribute=format \ -Wsuggest-attribute=noreturn \ -Wsuggest-attribute=pure \ + -Wswitch \ + -Wswitch-default \ + -Wsync-nand \ + -Wsystem-headers \ -Wtrampolines \ + -Wtrigraphs \ + -Wtype-limits \ + -Wuninitialized \ + -Wunknown-pragmas \ + -Wunsafe-loop-optimizations \ + -Wunused \ + -Wunused-but-set-parameter \ + -Wunused-but-set-variable \ + -Wunused-function \ + -Wunused-label \ + -Wunused-local-typedefs \ + -Wunused-macros \ + -Wunused-parameter \ + -Wunused-result \ + -Wunused-value \ + -Wunused-variable \ + -Wvarargs \ + -Wvariadic-macros \ + -Wvector-operation-performance \ + -Wvla \ + -Wvolatile-register-var \ + -Wwrite-strings \ + \ ; do gl_manywarn_set="$gl_manywarn_set $gl_manywarn_item" done - # Disable the missing-field-initializers warning if needed + # gcc --help=warnings outputs an unusual form for this option; list + # it here so that the above 'comm' command doesn't report a false match. + gl_manywarn_set="$gl_manywarn_set -Wnormalized=nfc" + + # These are needed for older GCC versions. + if test -n "$GCC"; then + case `($CC --version) 2>/dev/null` in + 'gcc (GCC) '[[0-3]].* | \ + 'gcc (GCC) '4.[[0-7]].*) + gl_manywarn_set="$gl_manywarn_set -fdiagnostics-show-option" + gl_manywarn_set="$gl_manywarn_set -funit-at-a-time" + ;; + esac + fi + + # Disable specific options as needed. if test "$gl_cv_cc_nomfi_needed" = yes; then gl_manywarn_set="$gl_manywarn_set -Wno-missing-field-initializers" fi + if test "$gl_cv_cc_uninitialized_supported" = no; then + gl_manywarn_set="$gl_manywarn_set -Wno-uninitialized" + fi + $1=$gl_manywarn_set ]) diff --git a/m4/virt-compile-warnings.m4 b/m4/virt-compile-warnings.m4 index 894ab59..532a777 100644 --- a/m4/virt-compile-warnings.m4 +++ b/m4/virt-compile-warnings.m4 @@ -2,7 +2,7 @@ dnl dnl Enable all known GCC compiler warnings, except for those dnl we can't yet cope with dnl -AC_DEFUN([LIBVIRT_SANDBOX_COMPILE_WARNINGS],[ +AC_DEFUN([LIBVIRT_COMPILE_WARNINGS],[ dnl ****************************** dnl More compiler warnings dnl ****************************** @@ -33,19 +33,96 @@ AC_DEFUN([LIBVIRT_SANDBOX_COMPILE_WARNINGS],[ dontwarn="$dontwarn -Wpadded" # GCC very confused with -O2 dontwarn="$dontwarn -Wunreachable-code" - # We explicitly need to remove const sometimes + # Too many to deal with + dontwarn="$dontwarn -Wconversion" + # Too many to deal with + dontwarn="$dontwarn -Wsign-conversion" + # GNULIB gettext.h violates + dontwarn="$dontwarn -Wvla" + # Many GNULIB header violations + dontwarn="$dontwarn -Wundef" + # Need to allow bad cast for execve() dontwarn="$dontwarn -Wcast-qual" - # Allow vars decl in the middle of blocks - dontwarn="$dontwarn -Wdeclaration-after-statement" - # Using long long is fine + # We need to use long long in many places dontwarn="$dontwarn -Wlong-long" - # Unused macros are ok + # We allow manual list of all enum cases without default: + dontwarn="$dontwarn -Wswitch-default" + # We allow optional default: instead of listing all enum values + dontwarn="$dontwarn -Wswitch-enum" + # Not a problem since we don't use -fstrict-overflow + dontwarn="$dontwarn -Wstrict-overflow" + # Not a problem since we don't use -funsafe-loop-optimizations + dontwarn="$dontwarn -Wunsafe-loop-optimizations" + # Things like virAsprintf mean we can't use this + dontwarn="$dontwarn -Wformat-nonliteral" + # Gnulib's stat-time.h violates this + dontwarn="$dontwarn -Waggregate-return" + # gcc 4.4.6 complains this is C++ only; gcc 4.7.0 implies this from -Wall + dontwarn="$dontwarn -Wenum-compare" + + # gcc 4.2 treats attribute(format) as an implicit attribute(nonnull), + # which triggers spurious warnings for our usage + AC_CACHE_CHECK([whether the C compiler's -Wformat allows NULL strings], + [lv_cv_gcc_wformat_null_works], [ + save_CFLAGS=$CFLAGS + CFLAGS='-Wunknown-pragmas -Werror -Wformat' + AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[ + #include <stddef.h> + static __attribute__ ((__format__ (__printf__, 1, 2))) int + foo (const char *fmt, ...) { return !fmt; } + ]], [[ + return foo(NULL); + ]])], + [lv_cv_gcc_wformat_null_works=yes], + [lv_cv_gcc_wformat_null_works=no]) + CFLAGS=$save_CFLAGS]) + + # Gnulib uses '#pragma GCC diagnostic push' to silence some + # warnings, but older gcc doesn't support this. + AC_CACHE_CHECK([whether pragma GCC diagnostic push works], + [lv_cv_gcc_pragma_push_works], [ + save_CFLAGS=$CFLAGS + CFLAGS='-Wunknown-pragmas -Werror' + AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[ + #pragma GCC diagnostic push + #pragma GCC diagnostic pop + ]])], + [lv_cv_gcc_pragma_push_works=yes], + [lv_cv_gcc_pragma_push_works=no]) + CFLAGS=$save_CFLAGS]) + if test $lv_cv_gcc_pragma_push_works = no; then + dontwarn="$dontwarn -Wmissing-prototypes" + dontwarn="$dontwarn -Wmissing-declarations" + dontwarn="$dontwarn -Wcast-align" + else + AC_DEFINE_UNQUOTED([WORKING_PRAGMA_PUSH], 1, + [Define to 1 if gcc supports pragma push/pop]) + fi + + dnl Check whether strchr(s, char variable) causes a bogus compile + dnl warning, which is the case with GCC < 4.6 on some glibc + AC_CACHE_CHECK([whether the C compiler's -Wlogical-op gives bogus warnings], + [lv_cv_gcc_wlogical_op_broken], [ + save_CFLAGS="$CFLAGS" + CFLAGS="-O2 -Wlogical-op -Werror" + AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[ + #include <string.h> + ]], [[ + const char *haystack; + char needle; + return strchr(haystack, needle) == haystack;]])], + [lv_cv_gcc_wlogical_op_broken=no], + [lv_cv_gcc_wlogical_op_broken=yes]) + CFLAGS="$save_CFLAGS"]) + + # We might fundamentally need some of these disabled forever, but + # ideally we'd turn many of them on + dontwarn="$dontwarn -Wfloat-equal" + dontwarn="$dontwarn -Wdeclaration-after-statement" + dontwarn="$dontwarn -Wpacked" dontwarn="$dontwarn -Wunused-macros" - - - # g_clear_object & G_ATOMIC_OP_USE_GCC_BUILTINS causes - # violations with this. XXX Fix glib ? - dontwarn="$dontwarn -Wbad-function-cast" + dontwarn="$dontwarn -Woverlength-strings" + dontwarn="$dontwarn -Wstack-protector" # Get all possible GCC warnings gl_MANYWARN_ALL_GCC([maybewarn]) @@ -53,78 +130,105 @@ AC_DEFUN([LIBVIRT_SANDBOX_COMPILE_WARNINGS],[ # Remove the ones we don't want, blacklisted earlier gl_MANYWARN_COMPLEMENT([wantwarn], [$maybewarn], [$dontwarn]) - # Check for $CC support of each warning - for w in $wantwarn; do - gl_WARN_ADD([$w]) - done - # GNULIB uses '-W' (aka -Wextra) which includes a bunch of stuff. # Unfortunately, this means you can't simply use '-Wsign-compare' # with gl_MANYWARN_COMPLEMENT # So we have -W enabled, and then have to explicitly turn off... - gl_WARN_ADD([-Wno-sign-compare]) - - # Due to gutils.h bug in g_bit_storage - gl_WARN_ADD([-Wno-sign-conversion]) - gl_WARN_ADD([-Wno-conversion]) - gl_WARN_ADD([-Wno-unused-parameter]) - # We can't enable this due to horrible spice_usb_device_get_description - # signature - gl_WARN_ADD([-Wno-format-nonliteral]) - - + wantwarn="$wantwarn -Wno-sign-compare" # GNULIB expects this to be part of -Wc++-compat, but we turn # that one off, so we need to manually enable this again - gl_WARN_ADD([-Wjump-misses-init]) + wantwarn="$wantwarn -Wjump-misses-init" + + # GNULIB turns on -Wformat=2 which implies -Wformat-nonliteral, + # so we need to manually re-exclude it. Also, older gcc 4.2 + # added an implied ATTRIBUTE_NONNULL on any parameter marked + # ATTRIBUTE_FMT_PRINT, which causes -Wformat failure on our + # intentional use of virReportError(code, NULL). + wantwarn="$wantwarn -Wno-format-nonliteral" + if test $lv_cv_gcc_wformat_null_works = no; then + wantwarn="$wantwarn -Wno-format" + fi # This should be < 256 really. Currently we're down to 4096, # but using 1024 bytes sized buffers (mostly for virStrerror) # stops us from going down further - gl_WARN_ADD([-Wframe-larger-than=4096]) - - # Use improved glibc headers - AH_VERBATIM([FORTIFY_SOURCE], - [/* Enable compile-time and run-time bounds-checking, and some warnings, - without upsetting newer glibc. */ - #if !defined _FORTIFY_SOURCE && defined __OPTIMIZE__ && __OPTIMIZE__ - # define _FORTIFY_SOURCE 2 - #endif - ]) + wantwarn="$wantwarn -Wframe-larger-than=4096" + dnl wantwarn="$wantwarn -Wframe-larger-than=256" # Extra special flags dnl -fstack-protector stuff passes gl_WARN_ADD with gcc dnl on Mingw32, but fails when actually used case $host in + aarch64-*-*) + dnl "error: -fstack-protector not supported for this target [-Werror]" + ;; *-*-linux*) - dnl Fedora only uses -fstack-protector, but doesn't seem to - dnl be great overhead in adding -fstack-protector-all instead - dnl gl_WARN_ADD([-fstack-protector]) - gl_WARN_ADD([-fstack-protector-all]) - gl_WARN_ADD([--param=ssp-buffer-size=4]) + dnl Prefer -fstack-protector-strong if it's available. + dnl There doesn't seem to be great overhead in adding + dnl -fstack-protector-all instead of -fstack-protector. + dnl + dnl We also don't need ssp-buffer-size with -all or -strong, + dnl since functions are protected regardless of buffer size. + dnl wantwarn="$wantwarn --param=ssp-buffer-size=4" + wantwarn="$wantwarn -fstack-protector-strong" + ;; + *-*-freebsd*) + dnl FreeBSD ships old gcc 4.2.1 which doesn't handle + dnl -fstack-protector-all well + wantwarn="$wantwarn -fstack-protector" + + wantwarn="$wantwarn -Wno-unused-command-line-argument" ;; esac - gl_WARN_ADD([-fexceptions]) - gl_WARN_ADD([-fasynchronous-unwind-tables]) - gl_WARN_ADD([-fdiagnostics-show-option]) - gl_WARN_ADD([-funit-at-a-time]) + wantwarn="$wantwarn -fexceptions" + wantwarn="$wantwarn -fasynchronous-unwind-tables" # Need -fipa-pure-const in order to make -Wsuggest-attribute=pure # fire even without -O. - gl_WARN_ADD([-fipa-pure-const]) - + wantwarn="$wantwarn -fipa-pure-const" # We should eventually enable this, but right now there are at # least 75 functions triggering warnings. - gl_WARN_ADD([-Wno-suggest-attribute=pure]) - gl_WARN_ADD([-Wno-suggest-attribute=const]) - + wantwarn="$wantwarn -Wno-suggest-attribute=pure" + wantwarn="$wantwarn -Wno-suggest-attribute=const" if test "$set_werror" = "yes" then - gl_WARN_ADD([-Werror]) + wantwarn="$wantwarn -Werror" fi - WARN_LDFLAGS=$WARN_CFLAGS - AC_SUBST([WARN_CFLAGS]) - AC_SUBST([WARN_LDFLAGS]) + # Check for $CC support of each warning + for w in $wantwarn; do + gl_WARN_ADD([$w]) + done + + case $host in + *-*-linux*) + dnl Fall back to -fstack-protector-all if -strong is not available + case $WARN_CFLAGS in + *-fstack-protector-strong*) + ;; + *) + gl_WARN_ADD(["-fstack-protector-all"]) + ;; + esac + ;; + esac + + # Silence certain warnings in gnulib, and use improved glibc headers + AC_DEFINE([lint], [1], + [Define to 1 if the compiler is checking for lint.]) + AH_VERBATIM([FORTIFY_SOURCE], + [/* Enable compile-time and run-time bounds-checking, and some warnings, + without upsetting newer glibc. */ + #if !defined _FORTIFY_SOURCE && defined __OPTIMIZE__ && __OPTIMIZE__ + # define _FORTIFY_SOURCE 2 + #endif + ]) + + if test "$gl_cv_warn_c__Wlogical_op" = yes && + test "$lv_cv_gcc_wlogical_op_broken" = yes; then + AC_DEFINE_UNQUOTED([BROKEN_GCC_WLOGICALOP], 1, + [Define to 1 if gcc -Wlogical-op reports false positives on strchr]) + fi ]) diff --git a/m4/warnings.m4 b/m4/warnings.m4 index 69d05a6..43156f4 100644 --- a/m4/warnings.m4 +++ b/m4/warnings.m4 @@ -1,5 +1,5 @@ -# warnings.m4 serial 5 -dnl Copyright (C) 2008-2012 Free Software Foundation, Inc. +# warnings.m4 serial 11 +dnl Copyright (C) 2008-2014 Free Software Foundation, Inc. dnl This file is free software; the Free Software Foundation dnl gives unlimited permission to copy and/or distribute it, dnl with or without modifications, as long as this notice is preserved. @@ -14,24 +14,66 @@ m4_ifdef([AS_VAR_APPEND], [m4_define([gl_AS_VAR_APPEND], [AS_VAR_SET([$1], [AS_VAR_GET([$1])$2])])]) -# gl_WARN_ADD(PARAMETER, [VARIABLE = WARN_CFLAGS]) -# ------------------------------------------------ -# Adds parameter to WARN_CFLAGS if the compiler supports it. For example, -# gl_WARN_ADD([-Wparentheses]). -AC_DEFUN([gl_WARN_ADD], -dnl FIXME: gl_Warn must be used unquoted until we can assume -dnl autoconf 2.64 or newer. -[AS_VAR_PUSHDEF([gl_Warn], [gl_cv_warn_$1])dnl -AC_CACHE_CHECK([whether compiler handles $1], m4_defn([gl_Warn]), [ - gl_save_CPPFLAGS="$CPPFLAGS" - CPPFLAGS="${CPPFLAGS} $1" - AC_PREPROC_IFELSE([AC_LANG_PROGRAM([])], - [AS_VAR_SET(gl_Warn, [yes])], - [AS_VAR_SET(gl_Warn, [no])]) - CPPFLAGS="$gl_save_CPPFLAGS" + +# gl_COMPILER_OPTION_IF(OPTION, [IF-SUPPORTED], [IF-NOT-SUPPORTED], +# [PROGRAM = AC_LANG_PROGRAM()]) +# ----------------------------------------------------------------- +# Check if the compiler supports OPTION when compiling PROGRAM. +# +# FIXME: gl_Warn must be used unquoted until we can assume Autoconf +# 2.64 or newer. +AC_DEFUN([gl_COMPILER_OPTION_IF], +[AS_VAR_PUSHDEF([gl_Warn], [gl_cv_warn_[]_AC_LANG_ABBREV[]_$1])dnl +AS_VAR_PUSHDEF([gl_Flags], [_AC_LANG_PREFIX[]FLAGS])dnl +AS_LITERAL_IF([$1], + [m4_pushdef([gl_Positive], m4_bpatsubst([$1], [^-Wno-], [-W]))], + [gl_positive="$1" +case $gl_positive in + -Wno-*) gl_positive=-W`expr "X$gl_positive" : 'X-Wno-\(.*\)'` ;; +esac +m4_pushdef([gl_Positive], [$gl_positive])])dnl +AC_CACHE_CHECK([whether _AC_LANG compiler handles $1], m4_defn([gl_Warn]), [ + gl_save_compiler_FLAGS="$gl_Flags" + gl_AS_VAR_APPEND(m4_defn([gl_Flags]), + [" $gl_unknown_warnings_are_errors ]m4_defn([gl_Positive])["]) + AC_LINK_IFELSE([m4_default([$4], [AC_LANG_PROGRAM([])])], + [AS_VAR_SET(gl_Warn, [yes])], + [AS_VAR_SET(gl_Warn, [no])]) + gl_Flags="$gl_save_compiler_FLAGS" ]) -AS_VAR_IF(gl_Warn, [yes], - [gl_AS_VAR_APPEND(m4_if([$2], [], [[WARN_CFLAGS]], [[$2]]), [" $1"])]) +AS_VAR_IF(gl_Warn, [yes], [$2], [$3]) +m4_popdef([gl_Positive])dnl +AS_VAR_POPDEF([gl_Flags])dnl AS_VAR_POPDEF([gl_Warn])dnl -m4_ifval([$2], [AS_LITERAL_IF([$2], [AC_SUBST([$2])], [])])dnl ]) + +# gl_UNKNOWN_WARNINGS_ARE_ERRORS +# ------------------------------ +# Clang doesn't complain about unknown warning options unless one also +# specifies -Wunknown-warning-option -Werror. Detect this. +AC_DEFUN([gl_UNKNOWN_WARNINGS_ARE_ERRORS], +[gl_COMPILER_OPTION_IF([-Werror -Wunknown-warning-option], + [gl_unknown_warnings_are_errors='-Wunknown-warning-option -Werror'], + [gl_unknown_warnings_are_errors=])]) + +# gl_WARN_ADD(OPTION, [VARIABLE = WARN_CFLAGS], +# [PROGRAM = AC_LANG_PROGRAM()]) +# --------------------------------------------- +# Adds parameter to WARN_CFLAGS if the compiler supports it when +# compiling PROGRAM. For example, gl_WARN_ADD([-Wparentheses]). +# +# If VARIABLE is a variable name, AC_SUBST it. +AC_DEFUN([gl_WARN_ADD], +[AC_REQUIRE([gl_UNKNOWN_WARNINGS_ARE_ERRORS]) +gl_COMPILER_OPTION_IF([$1], + [gl_AS_VAR_APPEND(m4_if([$2], [], [[WARN_CFLAGS]], [[$2]]), [" $1"])], + [], + [$3]) +m4_ifval([$2], + [AS_LITERAL_IF([$2], [AC_SUBST([$2])])], + [AC_SUBST([WARN_CFLAGS])])dnl +]) + +# Local Variables: +# mode: autoconf +# End: -- 2.0.4