# Copyright 1999-2023 Gentoo Authors

KEYWORDS="amd64 arm arm64 ppc ppc64 ~riscv sparc x86 ~amd64-linux ~ppc-macos ~x64-macos"

IUSE="

	default-compiler-rt default-libcxx default-lld llvm-libunwind

	hardened stricter

"

	default-compiler-rt? (

		sys-devel/clang-runtime[compiler-rt]

		llvm-libunwind? ( sys-libs/llvm-libunwind[static-libs] )

		!llvm-libunwind? ( sys-libs/libunwind[static-libs] )

	)

	!default-compiler-rt? ( sys-devel/gcc )

	default-libcxx? ( >=sys-libs/libcxx-${PV} )

	!default-libcxx? ( sys-devel/gcc )

	default-lld? ( sys-devel/lld )

	!default-lld? ( sys-devel/binutils )

"

IDEPEND="

	!default-compiler-rt? ( sys-devel/gcc-config )

	!default-libcxx? ( sys-devel/gcc-config )

pkg_pretend() {

	[[ ${CLANG_IGNORE_DEFAULT_RUNTIMES} ]] && return

	local flag missing_flags=()

	for flag in default-{compiler-rt,libcxx,lld}; do

		if ! use "${flag}" && has_version "sys-devel/clang[${flag}]"; then

			missing_flags+=( "${flag}" )

		fi

	done

	if [[ ${missing_flags[@]} ]]; then

		eerror "It seems that you have the following flags set on sys-devel/clang:"

		eerror

		eerror "  ${missing_flags[*]}"

		eerror

		eerror "The default runtimes are now set via flags on sys-devel/clang-common."

		eerror "The build is being aborted to prevent breakage.  Please either set"

		eerror "the respective flags on this ebuild, e.g.:"

		eerror

		eerror "  sys-devel/clang-common ${missing_flags[*]}"

		eerror

		eerror "or build with CLANG_IGNORE_DEFAULT_RUNTIMES=1."

		die "Mismatched defaults detected between sys-devel/clang and sys-devel/clang-common"

	fi

}

	insinto /etc/clang

	newins - gentoo-runtimes.cfg <<-EOF

		# This file is initially generated by sys-devel/clang-runtime.

		# It is used to control the default runtimes using by clang.

		--rtlib=$(usex default-compiler-rt compiler-rt libgcc)

		--unwindlib=$(usex default-compiler-rt libunwind libgcc)

		--stdlib=$(usex default-libcxx libc++ libstdc++)

		-fuse-ld=$(usex default-lld lld bfd)

	EOF

	newins - gentoo-gcc-install.cfg <<-EOF

		# This file is maintained by gcc-config.

		# It is used to specify the selected GCC installation.

	EOF

	newins - gentoo-common.cfg <<-EOF

		# This file contains flags common to clang, clang++ and clang-cpp.

		@gentoo-runtimes.cfg

		@gentoo-gcc-install.cfg

		@gentoo-hardened.cfg

	EOF

	# Baseline hardening (bug #851111)

	# (-fstack-clash-protection is omitted because of a possible Clang bug,

	# see bug #892537 and bug #865339.)

	newins - gentoo-hardened.cfg <<-EOF

		# Some of these options are added unconditionally, regardless of

		# USE=hardened, for parity with sys-devel/gcc.

		-fstack-protector-strong

		-fPIE

		-include "${EPREFIX}/usr/include/gentoo/fortify.h"

	EOF

	dodir /usr/include/gentoo

	local fortify_level=$(usex hardened 3 2)

	# We have to do this because glibc's headers warn if F_S is set

	# without optimization and that would at the very least be very noisy

	# during builds and at worst trigger many -Werror builds.

	cat >> "${ED}/usr/include/gentoo/fortify.h" <<- EOF || die

	#ifdef __clang__

	# pragma clang system_header

	#endif

	#ifndef _FORTIFY_SOURCE

	# if defined(__has_feature)

	#  define __GENTOO_HAS_FEATURE(x) __has_feature(x)

	# else

	#  define __GENTOO_HAS_FEATURE(x) 0

	# endif

	#

	# if defined(__OPTIMIZE__) && __OPTIMIZE__ > 0

	#  if !defined(__SANITIZE_ADDRESS__) && !__GENTOO_HAS_FEATURE(address_sanitizer) && !__GENTOO_HAS_FEATURE(memory_sanitizer)

	#   define _FORTIFY_SOURCE ${fortify_level}

	#  endif

	# endif

	# undef __GENTOO_HAS_FEATURE

	#endif

	EOF

	if use hardened ; then

		cat >> "${ED}/etc/clang/gentoo-hardened.cfg" <<-EOF || die

			# Options below are conditional on USE=hardened.

			-D_GLIBCXX_ASSERTIONS

			# Analogue to GLIBCXX_ASSERTIONS

			# https://libcxx.llvm.org/UsingLibcxx.html#assertions-mode

			-D_LIBCPP_ENABLE_ASSERTIONS=1

		EOF

	fi

	if use stricter; then

		newins - gentoo-stricter.cfg <<-EOF

			# This file increases the strictness of older clang versions

			# to match the newest upstream version.

			# clang-16 defaults

			-Werror=implicit-function-declaration

			-Werror=implicit-int

			-Werror=incompatible-function-pointer-types

		EOF

		cat >> "${ED}/etc/clang/gentoo-common.cfg" <<-EOF || die

			@gentoo-stricter.cfg

		EOF

	fi

	local tool

	for tool in clang{,++,-cpp}; do

		newins - "${tool}.cfg" <<-EOF

			# This configuration file is used by ${tool} driver.

			@gentoo-common.cfg

		EOF

	done

}

pkg_preinst() {

	if has_version -b sys-devel/gcc-config && has_version sys-devel/gcc

	then

		local gcc_path=$(gcc-config --get-lib-path 2>/dev/null)

		if [[ -n ${gcc_path} ]]; then

			cat >> "${ED}/etc/clang/gentoo-gcc-install.cfg" <<-EOF

				--gcc-install-dir="${gcc_path%%:*}"

			EOF

		fi

	fi