LLVM_COMPAT=( 20 )

MRUSTC_VERSION="0.12.0"

MRUSTC_RUST_VERSION="1.90.0"

RUST_OPTIONAL=1

# We bumped the rust-patches tag without bumping the revision for

# https://bugs.gentoo.org/963657, given that ithe patch affects only a

# specific use case (bootstrap with Rust 1.90.0).

RUST_PATCH_VER=${PV}_p1

	RUST_MIN_VER="1.88.0" # Update this as new `beta` releases come out.

inherit check-reqs estack edo flag-o-matic llvm-r1 multiprocessing optfeature \

	multilib multilib-build python-any-r1 rust rust-toolchain toolchain-funcs verify-sig

	SRC_URI="https://static.rust-lang.org/dist/${BETA_SNAPSHOT}/rustc-beta-src.tar.xz -> rustc-${PV}-src.tar.xz

		verify-sig? ( https://static.rust-lang.org/dist/${BETA_SNAPSHOT}/rustc-beta-src.tar.xz.asc

			-> rustc-${PV}-src.tar.xz.asc )

	MY_P="rustc-${PV}"

	SRC_URI="https://static.rust-lang.org/dist/${MY_P}-src.tar.xz

ALL_LLVM_TARGETS=( AArch64 AMDGPU ARC ARM AVR BPF CSKY DirectX Hexagon Lanai

	LoongArch M68k Mips MSP430 NVPTX PowerPC RISCV Sparc SPIRV SystemZ VE

	WebAssembly X86 XCore Xtensa )

IUSE="big-endian clippy cpu_flags_x86_sse2 debug dist doc llvm-libunwind lto mrustc-bootstrap"

IUSE+=" rustfmt rust-analyzer rust-src +system-llvm test ${ALL_LLVM_TARGETS[*]} ${ALL_RUST_SYSROOTS[*]}"

BDEPEND="${PYTHON_DEPS}

	mrustc-bootstrap? (

		~dev-lang/mrustc-${MRUSTC_VERSION}

		dev-build/cmake

		sys-devel/gcc:*

	)

	!mrustc-bootstrap? ( ${RUST_DEPEND} )

RDEPEND="${DEPEND}

REQUIRED_USE="|| ( ${ALL_LLVM_TARGETS[*]} )

	if use mrustc-bootstrap; then

		if ! tc-is-gcc; then

			# USE="mrustc-bootstrap" reqires that the build environment use GCC

			export CC=${CHOST}-gcc

			export CXX=${CHOST}-g++

			tc-is-gcc || die "tc-is-gcc failed in spite of CC=${CC}"

		fi

	else

		rust_pkg_setup

	fi

		verify-sig_verify_detached "${DISTDIR}"/rustc-${PV}-src.tar.xz{,.asc}

	if [[ ${PV} = *9999* ]]; then

		# We need to update / generate lockfiles for the workspace

		${CARGO} generate-lockfile --offline || die "Failed to generate lockfiles"

	fi

	# Apply patches for bootstrapping with a particular Rust version (RUST_SLOT).

	if [[ -n ${RUST_SLOT} ]]; then # Not set set if using mrustc-bootstrap

		local bootstrap_patchdir="${WORKDIR}/rust-patches-${RUST_PATCH_VER}/${RUST_SLOT}"

		if [[ -d "${bootstrap_patchdir}" ]]; then

			PATCHES+=(

				"${bootstrap_patchdir}"

			)

		fi

	fi

	if use mrustc-bootstrap; then

		pushd "${S}" 2>/dev/null || die

		einfo "Applying patches to enable bootstrap with mrustc ${MRUSTC_VERSION}"

		patch -p0 < "${BROOT}"/usr/share/mrustc-${MRUSTC_VERSION}/patches/rustc-${MRUSTC_RUST_VERSION}-src.patch ||

			die "Failed to patch sources to enable bootstrap with mrustc"

		popd 2>/dev/null || die

	fi

	if use mrustc-bootstrap; then

		local rust_stage0_root="${WORKDIR}/bootstrap/rust-${PV}"

	else

		local rust_stage0_root="$(${RUSTC} --print sysroot || die "Can't determine rust's sysroot")"

		# in case of prefix it will be already prefixed, as --print sysroot returns full path

		[[ -d ${rust_stage0_root} ]] || die "${rust_stage0_root} is not a directory"

	fi

		export CFLAGS_${wasm_target//-/_}="$(filter-flags '-mcpu*' '-march*' '-mtune*'; echo "$CFLAGS")"

llvm_bootstrap() {

	# Reference ${P}/src/bootstrap/native.rs for these values

	local llvm_cmake_opts=(

		"-G Ninja"

		"-DLLVM_TARGET_ARCH=${CFG_COMPILER_HOST_TRIPLE%%-*}"

		"-DLLVM_DEFAULT_TARGET_TRIPLE=${CFG_COMPILER_HOST_TRIPLE}"

		#;Mips;PowerPC;SystemZ;JSBackend;MSP430;Sparc;NVPTX

		"-DLLVM_TARGETS_TO_BUILD=${BOOTSTRAP_LLVM_TARGETS:=X86;ARM;AArch64}"

		"-DLLVM_ENABLE_ASSERTIONS=OFF"

		"-DLLVM_INCLUDE_EXAMPLES=OFF"

		"-DLLVM_INCLUDE_TESTS=OFF"

		"-DLLVM_INCLUDE_DOCS=OFF"

		"-DLLVM_INCLUDE_BENCHMARKS=OFF"

		"-DLLVM_ENABLE_ZLIB=OFF"

		"-DLLVM_ENABLE_TERMINFO=OFF"

		"-DLLVM_ENABLE_LIBEDIT=OFF"

		"-DCMAKE_CXX_COMPILER=$(tc-getCXX)"

		"-DCMAKE_C_COMPILER=$(tc-getCC)"

		"-DCMAKE_BUILD_TYPE=Release"

	)

	if [[ -z "${LLVM_CMAKE_OPTS_EXTRA}" ]]; then

		llvm_cmake_opts+=( "${LLVM_CMAKE_OPTS_EXTRA}")

	fi

	elog "Building bootstrap llvm ..."

	mkdir -p "${WORKDIR}/bootstrap/llvm" || die

	pushd "${WORKDIR}/bootstrap/llvm" 2>/dev/null || die

		edo cmake ${llvm_cmake_opts[*]} "${S}/src/llvm-project/llvm"

		eninja || die "Failed to build bootstrap llvm"

	popd 2>/dev/null || die

}

# High level steps:

# Our system mrustc package has built stdlib for our current platform.

# - Step 1: Use system-installed mrustc, (m)rust(c) stdlib, and minicargo to

#	bootstrap a `cargo` and `rustc` (mrustc-stage0)

# - Step 2: Use minicargo and the built `rustc` to build a working `sysroot`

#			(includes `std`, `panic_unwind``, `test`, etc.) (mrustc-stage0)

# - Step 3: Build build libs again (this time using `cargo` and `rustc`) (mrustc-stage1)

# - Step 4: Build a `rustc` using those libs (mrustc-stage1)

#  - Done so there's an optimised rustc around (mrustc is bad at codegen)

# - Step 5: Build `libstd` with this `rustc` (mrustc-stage2)

#  - Needed to match ABIs

# Stages:

# - mrustc-stage0: mrustc-built cargo and rustc

# - mrustc-stage1: rustc and sysroot built with mrustc-stage0

# - mrustc-stage2: rustc from stage1 with sysroot built with stage0

# See:

# - https://github.com/thepowersgang/mrustc/blob/master/run_rustc/Makefile

# - https://github.com/thepowersgang/mrustc/blob/master/TestRustcBootstrap.sh

# - Upstream Windows .cmd files are also a good reference for early bootstrap

mrustc_bootstrap() {

	export RUSTC_BOOTSTRAP=1 # Possibly the only intended use of this variable in ::gentoo

	# export these variables now and unset them at the end of the function so they don't leak

	# into the rest of the build.

	export CFG_COMPILER_HOST_TRIPLE="$(rust_abi)"

	export CFG_RELEASE="${MRUSTC_RUST_VERSION}"	# Let's pretend we're 1.90.0

	export CFG_RELEASE_CHANNEL="stable"

	export CFG_VERSION="${MRUSTC_RUST_VERSION}-stable-mrustc"

	export CFG_PREFIX="mrustc"

	export CFG_LIBDIR_RELATIVE="lib"

	# We actually patch our executable, but this suppresses a warning on every invocation of the bootstrap compiler.

	export MRUSTC_TARGET_VER="${MRUSTC_RUST_VERSION%.*}"

	export RUSTC_INSTALL_BINDIR="bin"

	export REAL_LIBRARY_PATH_VAR="LD_LIBRARY_PATH"

	export STD_ENV_ARCH="${CFG_COMPILER_HOST_TRIPLE%%-*}"

	# These flags are used in every invocation of our bootstrap `cargo`.

	local cargo_flags="--target ${CFG_COMPILER_HOST_TRIPLE} -j $(makeopts_jobs) --release --verbose"

	# for bootstrap, let's using the built-in stdlib of compiler (could be the bundled one)

	filter-flags '-stdlib=*'

	# mrustc requires gcc, so disable libcxx to avoid linker failure on w/o '-lstdc++'

	[[ "${LLVM_USE_LIBCXX}" == "1" ]] && unset LLVM_USE_LIBCXX

	local llvm_config_wrapper_cxxflags=0

	if use system-llvm; then

		export LLVM_CONFIG="$(get_llvm_prefix)/bin/llvm-config"

		local llvm_config_cxxflags=$(${LLVM_CONFIG} --cxxflags)

		elog "Checking llvm-config --cxxflags: '${llvm_config_cxxflags}'"

		[[ "${llvm_config_cxxflags}" =~ (^|[[:space:]])-stdlib=libc\+\+([[:space:]]|$) ]] && {

			elog "Found LLVM CXXFLAGS has \"--stdlib=libc++\""

			llvm_config_wrapper_cxxflags=1

		}

	else

		llvm_bootstrap

		export LLVM_CONFIG="${WORKDIR}/bootstrap/llvm/bin/llvm-config"

	fi

	elog "LLVM_CONFIG before wrappers: ${LLVM_CONFIG}"

	# workaround for gcc bug 122409 on musl by wrapping llvm-config

	# to append libc++ header if has "-stdlib=libc++"

	elog "Preparing wrapper of llvm-config (${WORKDIR}/llvm-config)"

	cat > ${WORKDIR}/llvm-config <<-EOF || die

	#!/bin/bash

	RULES=()

	for flag in "\$@"; do

	    case "\${flag}" in

	$([[ "${llvm_config_wrapper_cxxflags}" == 1 ]] && {

		echo "        --cxxflags) RULES+=( \"-E\" \"s@(^|[[:space:]]+)(-stdlib=libc\\+\\+)(\\$|[[:space:]])@\\1-I${EPREFIX}/usr/include/c++/v1 \\2\\3@g\" ) ;;"

	})

	        *)

	            ;;

	    esac

	done

	[[ -z "\${RULES}" ]] && {

	    ${LLVM_CONFIG} "\$@"

	} || {

	    ${LLVM_CONFIG} "\$@" | \\

	        tee -a ${T}/llvm-config.0.log | \\

	        sed "\${RULES[@]}" | \\

	        tee -a ${T}/llvm-config.1.log

	    exit \${PIPESTATUS[0]}

	}

	EOF

	export LLVM_CONFIG="${WORKDIR}/llvm-config"

	chmod +x ${WORKDIR}/llvm-config || die

	einfo "llvm-config wrapper contents:"

	cat "${LLVM_CONFIG}" || die

	echo

	# define the mrustc sysroot and common minicargo arguments.

	local mrustc_sysroot="${BROOT}/usr/lib/rust/mrustc-${MRUSTC_VERSION}/lib/rustlib/${CFG_COMPILER_HOST_TRIPLE}/lib"

	local minicargo_common_args=(

		"-L" "${mrustc_sysroot}"

		"-j" "$(makeopts_jobs)"

		"--vendor-dir" "${S}/vendor"

		"--manifest-overrides"

		"${BROOT}/usr/share/mrustc-${MRUSTC_VERSION}/patches/rustc-${MRUSTC_RUST_VERSION}-overrides.toml"

	)

	# There's a very good chance that minicargo and mrustc are not in the PATH.

	if ! command -v minicargo &> /dev/null; then

		export PATH="${BROOT}/usr/lib/rust/mrustc-${MRUSTC_VERSION}/bin:${PATH}"

	fi

	# Sanity check our bootstrap compiler & stdlib.

	elog "Sanity checking mrustc and stdlib ..."

	edo mrustc "${S}/tests/ui/parallel-rustc/hello_world.rs" -L "${mrustc_sysroot}" -o "${T}"/hello -g

	"${T}"/hello || die "Failed to run hello_world"

	# Seems fine, let's build some tools!

	# Step 1: Build a `cargo` and `rustc` using system-installed mrustc

	# Anything we produce is going to be terribly unoptimised; mrustc does not do fantastic codegen.

	# It's good enough to bootstrap the "real" rustc though.

	elog "Building bootstrap cargo and rustc using mrustc and minicargo (mrustc-stage0) ..."

	local stage0="${WORKDIR}/bootstrap/mrustc-stage0"

	mkdir -p "${stage0}" || die

	edo minicargo "${S}"/src/tools/cargo --output-dir "${stage0}"/cargo-build ${minicargo_common_args[*]}

	"${stage0}"/cargo-build/cargo --version || die "Bootstrap cargo failed basic sanity check"

	edo minicargo "${S}"/compiler/rustc --output-dir "${stage0}"/rustc-build ${minicargo_common_args[*]} \

		--features llvm

	"${stage0}"/rustc-build/rustc_main --version || die "Bootstrap rustc failed basic sanity check"

	# minicargo has special-casing for `rustc` so we need to rename it.

	mv "${stage0}"/rustc-build/rustc_main "${stage0}"/rustc-build/rustc || die "Failed to rename rustc_main to rustc"

	# rustc wants these here

	mkdir -p "${stage0}"/codegen-backends || die

	mv "${stage0}"/rustc-build/librustc_codegen_llvm.* "${stage0}"/codegen-backends || die

	# Step 2: use the bootstrapped rustc to build sysroot; we need to use `minicargo` for this -

	# mrustc does not accept all of the arguments that rustc does, even with the rustc_proxy wrapper.

	# `--script-overrides`:  If the overrides are available, build scripts (and build-deps) are not built

	# which is good since we don't have a working compiler yet, and can't build them.

	local stage0_sysroot_lib="${stage0}/lib/rustlib/${CFG_COMPILER_HOST_TRIPLE}/lib"

	# minicargo <= 0.12.0 doesn't create this directory and silently fails, besides it's better to be explicit, right?

	mkdir -p "${stage0_sysroot_lib}" || die "Failed to create stage0 directory"

	elog "Building 'sysroot' using bootstrap rustc (mrustc-stage0) ..."

	local o_dir="${BROOT}/usr/share/mrustc-${MRUSTC_VERSION}/script-overrides/stable-${MRUSTC_RUST_VERSION}-linux/"

	edo env MRUSTC_PATH="${stage0}/rustc-build/rustc" minicargo -j $(makeopts_jobs) --vendor-dir "${S}"/vendor \

		--script-overrides  "${o_dir}" \

		--output-dir "${stage0_sysroot_lib}" "${S}"/library/sysroot ||

			die "Failed to build sysroot with bootstrap rust (mrustc-stage0)"

	elog "Sanity checking sysroot and rustc ..."

	mkdir -p "${T}"/stage0-hello || die

	edo "${stage0}"/rustc-build/rustc -L "${stage0_sysroot_lib}" -g "${S}/tests/ui/parallel-rustc/hello_world.rs" \

		-o "${T}"/stage0-hello/hello

	"${T}"/stage0-hello/hello || die "Failed to run hello_world built with bootstrap rust stage0"

	elog "mrustc bootstrap stage0 complete!"

	# Step 3: Build a "proper" libstd, including dynamic libs using our bootstrap cargo and rustc.

	elog "Building 'sysroot' with the stage0 rustc (mrustc-stage1) ..."

	local stage1="${WORKDIR}/bootstrap/mrustc-stage1"

	local stage1_sysroot_lib="${stage1}/lib/rustlib/${CFG_COMPILER_HOST_TRIPLE}/lib"

	mkdir -p "${stage1_sysroot_lib}" || die "Failed to create stage1 directory"

	mkdir -p "${stage1}/bin" || die

	# Simplified to avoid calling rustc_proxy; We don't need stage1 rustc until after this is built...

	edo env RUSTFLAGS="-Z force-unstable-if-unmarked" CARGO_TARGET_DIR="${stage1}/sysroot-build" \

		RUSTC="${stage0}/rustc-build/rustc" "${stage0}"/cargo-build/cargo build ${cargo_flags} \

		--manifest-path "${S}/library/sysroot/Cargo.toml" --features panic-unwind

	# Move the built libs into the sysroot libdir.

	mv "${stage1}/sysroot-build/${CFG_COMPILER_HOST_TRIPLE}/release/deps"/*.{rlib,rmeta,so} \

		"${stage1_sysroot_lib}" || die "Failed to move stage1 libs to stage1 sysroot"

	# We need to copy the stage0 rustc to the stage1 sysroot; this "updates" the sysroot location and enables

	# resolution of stage1 libs. (run `rustc --print sysroot` on stage0 and stage1 rustc to verify)

	cp "${stage0}/rustc-build/rustc" "${stage1}/bin/rustc" || die "Failed to copy rustc to stage1 sysroot"

	# Step 4: Build `rustc` with itself, so we have a rustc with the right ABI.

	# This will be our final `rustc` for the bootstrap process.

	elog "Building rustc with stage1 libs (mrustc-stage1) ..."

	mkdir -p "${stage1}/rustc-build" || die

	edo env RUSTFLAGS="-Z force-unstable-if-unmarked -C link_args=-Wl,-rpath,\$ORIGIN/../lib" \

		LD_LIBRARY_PATH="${stage2_sysroot_lib}" CARGO_TARGET_DIR="${stage1}/rustc-build" \

		RUSTC="${stage1}/bin/rustc" TMPDIR="${T}" "${stage0}"/cargo-build/cargo build ${cargo_flags} \

		--manifest-path "${S}/compiler/rustc/Cargo.toml"  --features llvm

	# Step 5: Build `sysroot` with this `rustc` - Needed to match ABI

	# We need to use the previous sysroot; we could reuse that dir but it's easier to just copy it.

	elog "Building final 'sysroot' with the final rustc (mrustc-stage2) ..."

	local stage2="${WORKDIR}/bootstrap/mrustc-stage2"

	local stage2_sysroot_lib="${stage2}/lib/rustlib/${CFG_COMPILER_HOST_TRIPLE}/lib"

	mkdir -p "${stage2_sysroot_lib}" || die "Failed to create stage2 directory"

	mkdir -p "${stage2}/bin" || die

	# Copy required files from stage1 to stage2 sysroot

	cp "${stage1}/rustc-build/${CFG_COMPILER_HOST_TRIPLE}"/release/rustc-main "${stage2}/bin/rustc_binary" ||

		die "Failed to copy final rustc to stage2 sysroot"

	cp "${stage1}/rustc-build/${CFG_COMPILER_HOST_TRIPLE}"/release/librustc_driver.so "${stage2}/lib" ||

		die "Failed to copy librustc_driver to sysroot"

	cp "${stage1}/rustc-build/${CFG_COMPILER_HOST_TRIPLE}"/release/deps/*.{rlib,so} "${stage2_sysroot_lib}" ||

		die "Failed to copy final rustc libs to stage2 sysroot"

	cp "${stage1_sysroot_lib}"/* "${stage2_sysroot_lib}" || die "Failed to copy stage1 so files to stage2 sysroot"

	# There's a magic script used in place of rustc so that libs can be found

	cat <<- EOF > "${stage2}/bin/rustc" || die "Failed to create rustc wrapper"

		#!/bin/sh

		LD_LIBRARY_PATH="${stage2}/lib:${stage2_sysroot_lib}" ${stage2}/bin/rustc_binary "\$@"

	EOF

	chmod +x "${stage2}/bin/rustc" || die "Failed to make rustc wrapper executable"

	# Use rustc to build 'sysroot'; this is the final step in the bootstrap process.

	# rpath probably isn't needed here, but it doesn't hurt.

	edo env RUSTFLAGS="-Z force-unstable-if-unmarked -C link_args=-Wl,-rpath,\$ORIGIN/../lib" \

		CARGO_TARGET_DIR="${stage2}/stdlib-build" RUSTC="${stage2}/bin/rustc" \

		"${stage0}"/cargo-build/cargo build ${cargo_flags} --manifest-path "${S}/library/sysroot/Cargo.toml" \

		--features panic-unwind

	# Build our final output sysroot

	local output="${WORKDIR}/bootstrap/rust-${PV}"

	local output_sysroot_lib="${output}/lib/rustlib/${CFG_COMPILER_HOST_TRIPLE}/lib"

	mkdir -p "${output_sysroot_lib}" || die "Failed to create output directory"

	mkdir -p "${output}/bin" || die "Failed to create output directory"

	# Copy our various output files into the output sysroot

	# rustc

	cp "${stage1}/rustc-build/${CFG_COMPILER_HOST_TRIPLE}"/release/rustc-main "${output}/bin/rustc_binary" ||

		die "Failed to copy final rustc to output"

	cp "${stage1}/rustc-build/${CFG_COMPILER_HOST_TRIPLE}"/release/librustc_driver.so "${output}/lib" ||

		die "Failed to copy librustc_driver to output"

	cp "${stage1}/rustc-build/${CFG_COMPILER_HOST_TRIPLE}"/release/deps/*.{rlib,so} "${output_sysroot_lib}" ||

		die "Failed to copy final rustc libs to output"

	# cargo; no need to build an optimised cargo if we're using this to build a complelety new Rust.

	cp "${stage0}/cargo-build/cargo" "${output}/bin/cargo" || die "Failed to copy cargo to output"

	# libs

	mv "${stage2}/stdlib-build/${CFG_COMPILER_HOST_TRIPLE}/release/deps"/*.{rlib,rmeta,so} "${output_sysroot_lib}" ||

		die "Failed to copy stage2 libs to output"

	# Our trusty rustc wrapper

	cat <<- EOF > "${output}/bin/rustc" || die "Failed to create rustc wrapper"

		#!/bin/sh

		LD_LIBRARY_PATH="${output}/lib:${output_sysroot_lib}" ${output}/bin/rustc_binary "\$@"

	EOF

	chmod +x "${output}/bin/rustc" || die "Failed to make rustc wrapper executable"

	# Perform a sanity check on the final Rust.

	mkdir -p "${T}"/output-hello || die

	edo "${output}/bin/rustc" -L "${output_sysroot_lib}" -g "${S}/tests/ui/parallel-rustc/hello_world.rs" \

		-o "${T}"/output-hello/hello

	"${T}"/output-hello/hello || die "Failed to run hello_world built with bootstrapped Rust"

	elog "Successfully bootstrapped Rust using mrustc!"

	# Note: The Rust sysroot that we've produced is pretty close to what we'd expect from a normal Rust build.

	# If someone was so inclined they could build an optimised cargo using the stage2 rustc and sysroot,

	# and install the output directly. This is untested, as I'm sure there's more to it than that.

	# I'm satisfied with being able to build Rust normally at this point.

	# Tidy up the Rust sources; revert mrustc changes so Rust can be built normally.

	pushd "${S}" 2>/dev/null || die

		patch -R -p0 < "${BROOT}"/usr/share/mrustc-${MRUSTC_VERSION}/patches/rustc-${MRUSTC_RUST_VERSION}-src.patch ||

			die "Failed to revert mrustc patches"

	popd 2>/dev/null || die

	# Tidy up any environment variables we've set in the bootstrap process.

	unset CFG_COMPILER_HOST_TRIPLE CFG_RELEASE CFG_RELEASE_CHANNEL CFG_PREFIX CFG_VERSION CFG_LIBDIR_RELATIVE

	unset LLVM_CONFIG MRUSTC_TARGET_VER REAL_LIBRARY_PATH_VAR RUSTFLAGS RUSTC_BOOTSTRAP RUSTC_INSTALL_BINDIR

}

	use mrustc-bootstrap && mrustc_bootstrap

	# bug #689562, #689160

	rmdir -v "${ED}/usr/lib/${PN}/${SLOT}"/etc{/bash_completion.d,} || die

		local ver_i="${i}-${PV%%_*}"

	dosym "../../lib/${PN}/${SLOT}/share/doc/rust" "/usr/share/doc/${P}"

	newenvd - "50${P}" <<-_EOF_

		echo /usr/bin/clippy-driver >> "${T}/provider-${P}"

		echo /usr/bin/cargo-clippy >> "${T}/provider-${P}"

		echo /usr/bin/miri >> "${T}/provider-${P}"

		echo /usr/bin/cargo-miri >> "${T}/provider-${P}"

		echo /usr/bin/rustfmt >> "${T}/provider-${P}"

		echo /usr/bin/cargo-fmt >> "${T}/provider-${P}"

		echo /usr/lib/rust/libexec >> "${T}/provider-${P}"

		echo /usr/bin/rust-analyzer >> "${T}/provider-${P}"

		elog "for convenience they are installed under /usr/bin/rust-{gdb,lldb}-${PV}."