thesamesam/bashrc

## bashrc
# Distributed under the terms of the GNU General Public License v2
#
# Hook to make it easier to detect compiler output changes in src_configure with stricter Clang
# Outputs logs to /var/tmp/clang.
# Written by Sam James <sam@gentoo.org> and Arsen Arsenović <arsen@aarsen.me>
#
# For background, please see https://wiki.gentoo.org/wiki/Modern_C_porting.
#
# Instructions:
# 1. Install clang:15 or clang:16 or clang:17
# 2. Install ansifilter
# 3. Two options:
#    - Set CC=clang and CXX=clang++ in make.conf
#    - If you don't want to build your system using Clang, set PORTAGE_USE_CLANG_HOOK_GCC=1 too.
#      This will run configure tests using Clang in 'pretend' mode in parallel
#      but the actual results used on your system should be your normal compiler.
# 4. File any bugs hit using this hook as a blocker for tracker bug #870412
#
# Variables:
# - PORTAGE_USE_CLANG_HOOK=0 to disable (PORTAGE_USE_CLANG_HOOK=1 is default on to enable)
# - PORTAGE_USE_CLANG_HOOK_GCC=1 to use gcc 'for real' but Clang for the testing
#
# Notes:
# - To check /var/tmp/clang for `clang.diff` files likely to indicate problems, run:
#   find /var/tmp/clang | grep -i broken | sed -e 's:clang16-broken:clang.diff:g' | xargs grep -rsin "error:.*C99" -l | sort -t/ -k 4,5

: ${PORTAGE_USE_CLANG_HOOK:=1}

hook_timestamp='2023-11-30T22:24'

pre_src_prepare() {
	# If CC is set to something other than Clang, we shouldn't try
	# to override it (could even be done in the ebuild).
	if [[ -n ${CC} && ${CC} != *clang* ]] ; then
		return
	fi

	case ${EAPI} in
		[0123456])
			hv_args="--host-root"
			;;
		*)
			hv_args="-b"
			;;
	esac

	local ver
	for ver in 15 16 17 ; do
		has_version ${hv_args} sys-devel/clang:${ver} && __PORTAGE_HOOK_CLANG=clang-${ver}
	done

	# Change to the full path to avoid recursion
	__PORTAGE_HOOK_CLANG=$(type -P "${__PORTAGE_HOOK_CLANG}")

	if ! type -P ansifilter &>/dev/null ; then
		return
	fi

	if [[ -z ${__PORTAGE_HOOK_CLANG} ]] || ! type -P ${__PORTAGE_HOOK_CLANG} &>/dev/null ; then
		# Avoid issues in early setup when clang:15 or clang:16 haven't yet been emerged.
		export CC=gcc
		export CXX=g++
		return
	fi
}

pre_src_configure() {
	if [[ ${PORTAGE_USE_CLANG_HOOK} == 1 ]] ; then
		if [[ -n ${CC} && ${CC} != *clang* && -z ${PORTAGE_USE_CLANG_HOOK_GCC} ]] ; then
			return
		fi

		if ! type -P ansifilter &>/dev/null ; then
			return
		fi

		ewarn "Modern C testing: this build is using a /etc/portage/bashrc hook ($hook_timestamp)!"
		ewarn "Modern C testing: see https://wiki.gentoo.org/wiki/Modern_C_porting for more info."

		# Avoid noise from intentional ones...
		export ac_cv_c_undeclared_builtin_options="none needed"
		export gl_cv_compiler_check_decl_option="-Werror=implicit-function-declaration"

		if [[ ${CHOST} == *musl* ]] ; then
			if has_version dev-libs/libbsd ; then
				export ac_cv_func___fpurge=yes
				export ac_cv_func_fpurge=yes
				export ac_cv_have_decl_fpurge=no
				export gl_cv_func_fpurge_works=no
			fi

			# These should be fine on glibc IIRC but let's be safe until confirmed.
			export ac_cv_header_sys_types_h_makedev=no
			export gl_cv_minmax_in_limits_h=no
		else
			export ac_cv_have_decl_strerror_r="yes" # -Wint-conversion
		fi

		# Weird hangs (see timeout comment below w/ tee)
		has waf-utils ${INHERITED} && return
		# bug #885497
		has qmake-utils ${INHERITED} && return
		# bug #885497
		has qt5-build ${INHERITED} && return

		# Issues with CPP, easier to just avoid (bug #882363)
		if grep -q "x11-misc/imake" <<< "${BDEPEND}" ; then
			return
		fi

		# Change to the full path to avoid recursion
		__PORTAGE_HOOK_CLANG=$(type -P "${__PORTAGE_HOOK_CLANG}")

		mkdir "${T}"/clang-wrappers
		cat <<- EOF > "${T}"/clang-wrappers/clang
		#!/usr/bin/env bash
		hook_clang=${__PORTAGE_HOOK_CLANG}
		real_compiler=${__PORTAGE_HOOK_CLANG}

		if [[ -n \${PORTAGE_USE_CLANG_HOOK_GCC} ]] ; then
			if [[ -n \${CC} && \${CC##*/} == *clang* ]] ; then
				:;
			else
				real_compiler="${BROOT:-/}"/usr/bin/${CHOST}-gcc
			fi
		fi

		if [[ \$0 == *++ ]]; then
			real_compiler=\${real_compiler/clang/clang++}
			real_compiler=\${real_compiler/gcc/g++}
			hook_clang=\${hook_clang/clang/clang++}
			hook_clang=\${hook_clang/gcc/g++}
		fi

		if [[ \${PORTAGE_CLANG_HOOK_USE_REAL_COMPILER} -gt 1 ]]; then
			# clang's self recursing... try your best!
			case "\${real_compiler}" in
				*++*) real_compiler="/usr/bin/\${CHOST+\${CHOST}-}g++" ;;
				*) real_compiler="/usr/bin/\${CHOST+\${CHOST}-}gcc" ;;
			esac
			real_compiler="\${real_compiler/clang/gcc}"
		fi

		# Safety net against recursive calls
		PORTAGE_orig_USE_REAL_COMP="\${PORTAGE_CLANG_HOOK_USE_REAL_COMPILER}"
		export PORTAGE_CLANG_HOOK_USE_REAL_COMPILER=\$((PORTAGE_CLANG_HOOK_USE_REAL_COMPILER+1))

		if [[ \${PORTAGE_orig_USE_REAL_COMP} ]]; then
			exec \${real_compiler} "\$@"
		fi

		export CFLAGS="${CFLAGS/-fdiagnostics-color=always}"
		export CFLAGS="${CFLAGS/-fdiagnostics-urls=never}"

		# - Need > /dev/null for sys-libs/musl
		# - No LTO because of the noise it generates in diffs (temps)
		cl1() {
			\${hook_clang} -fno-lto -Wno-unused-command-line-argument \
				-Wno-error=implicit-function-declaration \
				-Wno-error=implicit-int \
				-Wno-error=int-conversion \
				-Wno-error=incompatible-function-pointer-types \
				-Wno-error=incompatible-pointer-types \
				-Wno-error=return-type \
				${CFLAGS} \
				\$@ 2>&1 \
                                -fdiagnostics-color=never | ansifilter | sed \
				-e "s:14.0.6:14.ignoreme:g" \
				-e "s:15.0.0:14.ignoreme:g" \
				-e "s:clang-\(14\|15\|16\|17\):clang-ignoreme:g" \
				-e 's:clang version \([0-9]\+\)\.[0-9]\.[0-9]:clang version ignoreme:' \
				-e "s:/usr/lib/llvm/\(14\|15\|16\|17\)/:/usr/lib/llvm/ignoreme/:g" \
				-e "s:conftest-.*\.o:conftest.o:g" \
				-e "s_conftest\.c\:[0-9]\+\:[0-9]\+_ignoreme_g" \
				-e "s:garbage2:ignoreme:" \
				-e "s:garbage:ignoreme:" \
				-e "/ac_nonexistent.h/d" \
				-e '/clang-\(14\|15\|16\|17\|ignoreme\): error: no input files/d' \
				-e '/clang-\(14\|15\|16\|17\|ignoreme\): error: unsupported option/d' \
				-e '/clang-\(14\|15\|16\|17\|ignoreme\): error: unknown argument/d' \
				-e '/clang-\(14\|15\|16\|17\|ignoreme\): error: no such file or directory/d' \
				-e '/clang-\(14\|15\|16\|17\|ignoreme\): error: linker command failed/d' \
				-e '/[0-9]\+ \(warning\|error\) generated/d' | tee -a "${T}"/clang16-safe.log > /dev/null

			if ! [[ \${PIPESTATUS[0]} -eq 0 ]] ; then
				touch "${T}"/clang16-safe-failed
			fi
		}
		# TODO: No -Werror=strict-prototypes here for now as AC_PROG_LEX, AC_CHECK_FUNCS rely on it
		# also, I think Clang 15.0.1 (which reverts the other bits) keeps that in anyway.
		cl2() {
			\${hook_clang} -fno-lto -Wno-unused-command-line-argument \
				-Werror=implicit-function-declaration \
				-Werror=implicit-int \
				-Werror=int-conversion \
				-Werror=incompatible-function-pointer-types \
				-Werror=incompatible-pointer-types \
				-Werror=return-type \
				${CFLAGS} \
				\$@ 2>&1 \
				-fdiagnostics-color=never | ansifilter | sed \
				-e "s:14.0.6:14.ignoreme:g" \
				-e "s:15.0.0:14.ignoreme:g" \
				-e "s:clang-\(14\|15\|16\|17\):clang-ignoreme:g" \
				-e 's:clang version \([0-9]\+\)\.[0-9]\.[0-9]:clang version ignoreme:' \
				-e "s:/usr/lib/llvm/\(14\|15\|16\|17\)/:/usr/lib/llvm/ignoreme/:g" \
				-e "s:15:14:g" \
				-e "s:conftest-.*\.o:conftest.o:g" \
				-e "s_conftest\.c\:[0-9]\+\:[0-9]\+_ignoreme_g" \
				-e "s:garbage2:ignoreme:" \
				-e "s:garbage:ignoreme:" \
				-e "/ac_nonexistent.h/d" \
				-e '/clang-\(14\|15\|16\|17\|ignoreme\): error: no input files/d' \
				-e '/clang-\(14\|15\|16\|17\|ignoreme\): error: unsupported option/d' \
				-e '/clang-\(14\|15\|16\|17\|ignoreme\): error: unknown argument/d' \
				-e '/clang-\(14\|15\|16\|17\|ignoreme\): error: no such file or directory/d' \
				-e '/clang-\(14\|15\|16\|17\|ignoreme\): error: linker command failed/d' \
				-e '/[0-9]\+ \(warning\|error\) generated/d' | tee -a "${T}"/clang16-errors.log > /dev/null

			if ! [[ \${PIPESTATUS[0]} -eq 0 ]] ; then
				touch "${T}"/clang16-errors-failed
			fi
		}

		# Safety net against recursive calls
		export PORTAGE_CLANG_HOOK_USE_REAL_COMPILER=1
		# Because clang can invoke GCC
		export PORTAGE_USE_CLANG_HOOK_GCC=1

		# - Just run it again as it's easier for anything which wants to parse stdout/stderr,
		# and we're not concerned about performance for this experiment anyway.
		# - We have to do the tee & pipe dance to not greedily consume stdin: bug 870985.
		# - Timeout as a safety net because we don't ever want to make a build hang. Occurs
		# with waf sometimes (being investigated), but we should keep the timeout after that anyway.
		timeout --preserve-status -s PIPE 10 tee -p >(cl1 "\$@" -o "${T}"/garbage.\$\$) >(cl2 "\$@" -o "${T}"/garbage2.\$\$) | \${real_compiler} "\$@"
		ret="\${PIPESTATUS[1]}"

		# If at least one of them succeeded, then complain if *only* one of them did.
		if [[ -f "${T}"/clang16-safe-failed || -f "${T}"/clang16-errors-failed ]] ; then
			if ! [[ -f "${T}"/clang16-safe-failed && -f "${T}"/clang16-errors-failed ]] ; then
				touch "${T}"/clang16-broken
			fi
		fi

		rm -f "${T}"/clang16-safe-failed "${T}"/clang16-errors-failed
		exit \${ret}
		EOF

		chmod +x "${T}"/clang-wrappers/clang

		if in_iuse clang ; then
			# If an ebuild is trying to force compiler choice, it gets tricky
			# when we interfere with it. It's easier to just leave things be.
			# Firefox for example will get confused in its homebrew configure script.
			:;
		else
			# TODO: cc, ${CHOST}-cc?
			for alias in ${CHOST}-gcc gcc ${CHOST}-clang \
				     ${CHOST}-g++ g++ ${CHOST}-clang++; do
				ln -s "${T}"/clang-wrappers/clang "${T}"/clang-wrappers/${alias} || exit 1
				chmod +x "${T}"/clang-wrappers/${alias}
			done

			# -Werror=strict-prototypes
			# TODO: add -Werror=int-conversion?
			# TODO: add -Werror=incompatible-function-pointer-types here? (Clang only)
			export CFLAGS="${CFLAGS} -Werror=implicit-function-declaration -Werror=implicit-int"
			export PATH="${T}/clang-wrappers:${PATH}"
		fi
	fi
}

pre_src_compile() {
	if [[ -f "${T}"/clang16-errors.log ]] ; then
		rm -rf "${EROOT}"/var/tmp/clang/${CATEGORY}/${PF}
		mkdir -p "${EROOT}"/var/tmp/clang/${CATEGORY}/${PF}

		cp -rv "${T}"/clang16-{errors,safe}.log "${EROOT}"/var/tmp/clang/${CATEGORY}/${PF}

		if diff -ruN "${T}"/clang16-{safe,errors}.log > "${EROOT}"/var/tmp/clang/${CATEGORY}/${PF}/clang.diff ; then
			# No point in keeping an empty diff around if no differences.
			rm "${EROOT}"/var/tmp/clang/${CATEGORY}/${PF}/clang.diff
		fi

		[[ -f "${T}"/clang16-broken ]] && touch "${EROOT}"/var/tmp/clang/${CATEGORY}/${PF}/clang16-broken
	fi

	# We want to just delete the wrapper rather than mess with PATH again, as the ebuild
	# may have modified PATH itself.
	export PORTAGE_CLANG_HOOK_USE_REAL_COMPILER=1
	# TODO: commented out because CMake hardcodes the path to the discovered binary
	#rm -f "${T}"/clang-wrappers/{clang,gcc,cc,${CHOST}-gcc,${CHOST}-clang}
}

post_src_install() {
	if [[ ${PORTAGE_USE_CLANG_HOOK} == 1 && -f "${EROOT}"/var/tmp/clang/${CATEGORY}/${PF}/clang16-broken ]] ; then
		if grep -q "error:.*C99" "${EROOT}"/var/tmp/clang/${CATEGORY}/${PF}/clang.diff ; then
			eqawarn "Clang 16 testing: Found possible issues in configure!"
			eqawarn "Clang 16 testing: Please check "${EROOT}"/var/tmp/clang/${CATEGORY}/${PF}/clang.diff"
		fi
	fi
}

# Local variables:
# eval: (add-hook 'before-save-hook 'time-stamp)
# time-stamp-start: "hook_timestamp='"
# time-stamp-format: "%:y-%02m-%02dT%02H:%02M"
# time-stamp-time-zone: "UTC"
# time-stamp-end: "'"
# time-stamp-line-limit: 32
# mode: sh
# End:
	# Distributed under the terms of the GNU General Public License v2
	#
	# Hook to make it easier to detect compiler output changes in src_configure with stricter Clang
	# Outputs logs to /var/tmp/clang.
	# Written by Sam James <sam@gentoo.org> and Arsen Arsenović <arsen@aarsen.me>
	#
	# For background, please see https://wiki.gentoo.org/wiki/Modern_C_porting.
	#
	# Instructions:
	# 1. Install clang:15 or clang:16 or clang:17
	# 2. Install ansifilter
	# 3. Two options:
	# - Set CC=clang and CXX=clang++ in make.conf
	# - If you don't want to build your system using Clang, set PORTAGE_USE_CLANG_HOOK_GCC=1 too.
	# This will run configure tests using Clang in 'pretend' mode in parallel
	# but the actual results used on your system should be your normal compiler.
	# 4. File any bugs hit using this hook as a blocker for tracker bug #870412
	#
	# Variables:
	# - PORTAGE_USE_CLANG_HOOK=0 to disable (PORTAGE_USE_CLANG_HOOK=1 is default on to enable)
	# - PORTAGE_USE_CLANG_HOOK_GCC=1 to use gcc 'for real' but Clang for the testing
	#
	# Notes:
	# - To check /var/tmp/clang for `clang.diff` files likely to indicate problems, run:
	# find /var/tmp/clang \| grep -i broken \| sed -e 's:clang16-broken:clang.diff:g' \| xargs grep -rsin "error:.*C99" -l \| sort -t/ -k 4,5

	: ${PORTAGE_USE_CLANG_HOOK:=1}

	hook_timestamp='2023-11-30T22:24'

	pre_src_prepare() {
	# If CC is set to something other than Clang, we shouldn't try
	# to override it (could even be done in the ebuild).
	if [[ -n ${CC} && ${CC} != clang ]] ; then
	return
	fi

	case ${EAPI} in
	[0123456])
	hv_args="--host-root"
	;;
	*)
	hv_args="-b"
	;;
	esac

	local ver
	for ver in 15 16 17 ; do
	has_version ${hv_args} sys-devel/clang:${ver} && __PORTAGE_HOOK_CLANG=clang-${ver}
	done

	# Change to the full path to avoid recursion
	__PORTAGE_HOOK_CLANG=$(type -P "${__PORTAGE_HOOK_CLANG}")

	if ! type -P ansifilter &>/dev/null ; then
	return
	fi

	if [[ -z ${__PORTAGE_HOOK_CLANG} ]] \|\| ! type -P ${__PORTAGE_HOOK_CLANG} &>/dev/null ; then
	# Avoid issues in early setup when clang:15 or clang:16 haven't yet been emerged.
	export CC=gcc
	export CXX=g++
	return
	fi
	}

	pre_src_configure() {
	if [[ ${PORTAGE_USE_CLANG_HOOK} == 1 ]] ; then
	if [[ -n ${CC} && ${CC} != clang && -z ${PORTAGE_USE_CLANG_HOOK_GCC} ]] ; then
	return
	fi

	if ! type -P ansifilter &>/dev/null ; then
	return
	fi

	ewarn "Modern C testing: this build is using a /etc/portage/bashrc hook ($hook_timestamp)!"
	ewarn "Modern C testing: see https://wiki.gentoo.org/wiki/Modern_C_porting for more info."

	# Avoid noise from intentional ones...
	export ac_cv_c_undeclared_builtin_options="none needed"
	export gl_cv_compiler_check_decl_option="-Werror=implicit-function-declaration"

	if [[ ${CHOST} == musl ]] ; then
	if has_version dev-libs/libbsd ; then
	export ac_cv_func___fpurge=yes
	export ac_cv_func_fpurge=yes
	export ac_cv_have_decl_fpurge=no
	export gl_cv_func_fpurge_works=no
	fi

	# These should be fine on glibc IIRC but let's be safe until confirmed.
	export ac_cv_header_sys_types_h_makedev=no
	export gl_cv_minmax_in_limits_h=no
	else
	export ac_cv_have_decl_strerror_r="yes" # -Wint-conversion
	fi

	# Weird hangs (see timeout comment below w/ tee)
	has waf-utils ${INHERITED} && return
	# bug #885497
	has qmake-utils ${INHERITED} && return
	# bug #885497
	has qt5-build ${INHERITED} && return

	# Issues with CPP, easier to just avoid (bug #882363)
	if grep -q "x11-misc/imake" <<< "${BDEPEND}" ; then
	return
	fi

	# Change to the full path to avoid recursion
	__PORTAGE_HOOK_CLANG=$(type -P "${__PORTAGE_HOOK_CLANG}")

	mkdir "${T}"/clang-wrappers
	cat <<- EOF > "${T}"/clang-wrappers/clang
	#!/usr/bin/env bash
	hook_clang=${__PORTAGE_HOOK_CLANG}
	real_compiler=${__PORTAGE_HOOK_CLANG}

	if [[ -n \${PORTAGE_USE_CLANG_HOOK_GCC} ]] ; then
	if [[ -n \${CC} && \${CC##/} == clang* ]] ; then
	:;
	else
	real_compiler="${BROOT:-/}"/usr/bin/${CHOST}-gcc
	fi
	fi

	if [[ \$0 == *++ ]]; then
	real_compiler=\${real_compiler/clang/clang++}
	real_compiler=\${real_compiler/gcc/g++}
	hook_clang=\${hook_clang/clang/clang++}
	hook_clang=\${hook_clang/gcc/g++}
	fi

	if [[ \${PORTAGE_CLANG_HOOK_USE_REAL_COMPILER} -gt 1 ]]; then
	# clang's self recursing... try your best!
	case "\${real_compiler}" in
	++) real_compiler="/usr/bin/\${CHOST+\${CHOST}-}g++" ;;
	*) real_compiler="/usr/bin/\${CHOST+\${CHOST}-}gcc" ;;
	esac
	real_compiler="\${real_compiler/clang/gcc}"
	fi

	# Safety net against recursive calls
	PORTAGE_orig_USE_REAL_COMP="\${PORTAGE_CLANG_HOOK_USE_REAL_COMPILER}"
	export PORTAGE_CLANG_HOOK_USE_REAL_COMPILER=\$((PORTAGE_CLANG_HOOK_USE_REAL_COMPILER+1))

	if [[ \${PORTAGE_orig_USE_REAL_COMP} ]]; then
	exec \${real_compiler} "\$@"
	fi

	export CFLAGS="${CFLAGS/-fdiagnostics-color=always}"
	export CFLAGS="${CFLAGS/-fdiagnostics-urls=never}"

	# - Need > /dev/null for sys-libs/musl
	# - No LTO because of the noise it generates in diffs (temps)
	cl1() {
	\${hook_clang} -fno-lto -Wno-unused-command-line-argument \
	-Wno-error=implicit-function-declaration \
	-Wno-error=implicit-int \
	-Wno-error=int-conversion \
	-Wno-error=incompatible-function-pointer-types \
	-Wno-error=incompatible-pointer-types \
	-Wno-error=return-type \
	${CFLAGS} \
	\$@ 2>&1 \
	-fdiagnostics-color=never \| ansifilter \| sed \
	-e "s:14.0.6:14.ignoreme:g" \
	-e "s:15.0.0:14.ignoreme:g" \
	-e "s:clang-\(14\\|15\\|16\\|17\):clang-ignoreme:g" \
	-e 's:clang version \([0-9]\+\)\.[0-9]\.[0-9]:clang version ignoreme:' \
	-e "s:/usr/lib/llvm/\(14\\|15\\|16\\|17\)/:/usr/lib/llvm/ignoreme/:g" \
	-e "s:conftest-.*\.o:conftest.o:g" \
	-e "s_conftest\.c\:[0-9]\+\:[0-9]\+_ignoreme_g" \
	-e "s:garbage2:ignoreme:" \
	-e "s:garbage:ignoreme:" \
	-e "/ac_nonexistent.h/d" \
	-e '/clang-\(14\\|15\\|16\\|17\\|ignoreme\): error: no input files/d' \
	-e '/clang-\(14\\|15\\|16\\|17\\|ignoreme\): error: unsupported option/d' \
	-e '/clang-\(14\\|15\\|16\\|17\\|ignoreme\): error: unknown argument/d' \
	-e '/clang-\(14\\|15\\|16\\|17\\|ignoreme\): error: no such file or directory/d' \
	-e '/clang-\(14\\|15\\|16\\|17\\|ignoreme\): error: linker command failed/d' \
	-e '/[0-9]\+ \(warning\\|error\) generated/d' \| tee -a "${T}"/clang16-safe.log > /dev/null

	if ! [[ \${PIPESTATUS[0]} -eq 0 ]] ; then
	touch "${T}"/clang16-safe-failed
	fi
	}
	# TODO: No -Werror=strict-prototypes here for now as AC_PROG_LEX, AC_CHECK_FUNCS rely on it
	# also, I think Clang 15.0.1 (which reverts the other bits) keeps that in anyway.
	cl2() {
	\${hook_clang} -fno-lto -Wno-unused-command-line-argument \
	-Werror=implicit-function-declaration \
	-Werror=implicit-int \
	-Werror=int-conversion \
	-Werror=incompatible-function-pointer-types \
	-Werror=incompatible-pointer-types \
	-Werror=return-type \
	${CFLAGS} \
	\$@ 2>&1 \
	-fdiagnostics-color=never \| ansifilter \| sed \
	-e "s:14.0.6:14.ignoreme:g" \
	-e "s:15.0.0:14.ignoreme:g" \
	-e "s:clang-\(14\\|15\\|16\\|17\):clang-ignoreme:g" \
	-e 's:clang version \([0-9]\+\)\.[0-9]\.[0-9]:clang version ignoreme:' \
	-e "s:/usr/lib/llvm/\(14\\|15\\|16\\|17\)/:/usr/lib/llvm/ignoreme/:g" \
	-e "s:15:14:g" \
	-e "s:conftest-.*\.o:conftest.o:g" \
	-e "s_conftest\.c\:[0-9]\+\:[0-9]\+_ignoreme_g" \
	-e "s:garbage2:ignoreme:" \
	-e "s:garbage:ignoreme:" \
	-e "/ac_nonexistent.h/d" \
	-e '/clang-\(14\\|15\\|16\\|17\\|ignoreme\): error: no input files/d' \
	-e '/clang-\(14\\|15\\|16\\|17\\|ignoreme\): error: unsupported option/d' \
	-e '/clang-\(14\\|15\\|16\\|17\\|ignoreme\): error: unknown argument/d' \
	-e '/clang-\(14\\|15\\|16\\|17\\|ignoreme\): error: no such file or directory/d' \
	-e '/clang-\(14\\|15\\|16\\|17\\|ignoreme\): error: linker command failed/d' \
	-e '/[0-9]\+ \(warning\\|error\) generated/d' \| tee -a "${T}"/clang16-errors.log > /dev/null

	if ! [[ \${PIPESTATUS[0]} -eq 0 ]] ; then
	touch "${T}"/clang16-errors-failed
	fi
	}

	# Safety net against recursive calls
	export PORTAGE_CLANG_HOOK_USE_REAL_COMPILER=1
	# Because clang can invoke GCC
	export PORTAGE_USE_CLANG_HOOK_GCC=1

	# - Just run it again as it's easier for anything which wants to parse stdout/stderr,
	# and we're not concerned about performance for this experiment anyway.
	# - We have to do the tee & pipe dance to not greedily consume stdin: bug 870985.
	# - Timeout as a safety net because we don't ever want to make a build hang. Occurs
	# with waf sometimes (being investigated), but we should keep the timeout after that anyway.
	timeout --preserve-status -s PIPE 10 tee -p >(cl1 "\$@" -o "${T}"/garbage.\$\$) >(cl2 "\$@" -o "${T}"/garbage2.\$\$) \| \${real_compiler} "\$@"
	ret="\${PIPESTATUS[1]}"

	# If at least one of them succeeded, then complain if only one of them did.
	if [[ -f "${T}"/clang16-safe-failed \|\| -f "${T}"/clang16-errors-failed ]] ; then
	if ! [[ -f "${T}"/clang16-safe-failed && -f "${T}"/clang16-errors-failed ]] ; then
	touch "${T}"/clang16-broken
	fi
	fi

	rm -f "${T}"/clang16-safe-failed "${T}"/clang16-errors-failed
	exit \${ret}
	EOF

	chmod +x "${T}"/clang-wrappers/clang

	if in_iuse clang ; then
	# If an ebuild is trying to force compiler choice, it gets tricky
	# when we interfere with it. It's easier to just leave things be.
	# Firefox for example will get confused in its homebrew configure script.
	:;
	else
	# TODO: cc, ${CHOST}-cc?
	for alias in ${CHOST}-gcc gcc ${CHOST}-clang \
	${CHOST}-g++ g++ ${CHOST}-clang++; do
	ln -s "${T}"/clang-wrappers/clang "${T}"/clang-wrappers/${alias} \|\| exit 1
	chmod +x "${T}"/clang-wrappers/${alias}
	done

	# -Werror=strict-prototypes
	# TODO: add -Werror=int-conversion?
	# TODO: add -Werror=incompatible-function-pointer-types here? (Clang only)
	export CFLAGS="${CFLAGS} -Werror=implicit-function-declaration -Werror=implicit-int"
	export PATH="${T}/clang-wrappers:${PATH}"
	fi
	fi
	}

	pre_src_compile() {
	if [[ -f "${T}"/clang16-errors.log ]] ; then
	rm -rf "${EROOT}"/var/tmp/clang/${CATEGORY}/${PF}
	mkdir -p "${EROOT}"/var/tmp/clang/${CATEGORY}/${PF}

	cp -rv "${T}"/clang16-{errors,safe}.log "${EROOT}"/var/tmp/clang/${CATEGORY}/${PF}

	if diff -ruN "${T}"/clang16-{safe,errors}.log > "${EROOT}"/var/tmp/clang/${CATEGORY}/${PF}/clang.diff ; then
	# No point in keeping an empty diff around if no differences.
	rm "${EROOT}"/var/tmp/clang/${CATEGORY}/${PF}/clang.diff
	fi

	[[ -f "${T}"/clang16-broken ]] && touch "${EROOT}"/var/tmp/clang/${CATEGORY}/${PF}/clang16-broken
	fi

	# We want to just delete the wrapper rather than mess with PATH again, as the ebuild
	# may have modified PATH itself.
	export PORTAGE_CLANG_HOOK_USE_REAL_COMPILER=1
	# TODO: commented out because CMake hardcodes the path to the discovered binary
	#rm -f "${T}"/clang-wrappers/{clang,gcc,cc,${CHOST}-gcc,${CHOST}-clang}
	}

	post_src_install() {
	if [[ ${PORTAGE_USE_CLANG_HOOK} == 1 && -f "${EROOT}"/var/tmp/clang/${CATEGORY}/${PF}/clang16-broken ]] ; then
	if grep -q "error:.*C99" "${EROOT}"/var/tmp/clang/${CATEGORY}/${PF}/clang.diff ; then
	eqawarn "Clang 16 testing: Found possible issues in configure!"
	eqawarn "Clang 16 testing: Please check "${EROOT}"/var/tmp/clang/${CATEGORY}/${PF}/clang.diff"
	fi
	fi
	}

	# Local variables:
	# eval: (add-hook 'before-save-hook 'time-stamp)
	# time-stamp-start: "hook_timestamp='"
	# time-stamp-format: "%:y-%02m-%02dT%02H:%02M"
	# time-stamp-time-zone: "UTC"
	# time-stamp-end: "'"
	# time-stamp-line-limit: 32
	# mode: sh
	# End: