commit: aceba9b0c34432f22fe86c7f9f1f8121d6cf1b7c
Author: Matt Jolly <kangie <AT> gentoo <DOT> org>
AuthorDate: Tue Mar 10 03:50:34 2026 +0000
Commit: Matt Jolly <kangie <AT> gentoo <DOT> org>
CommitDate: Tue Mar 10 03:52:56 2026 +0000
URL: https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=aceba9b0
dev-lang/rust: bump mrustc-bootstrap to 1.90.0
This commit enables users to bootstrap Rust using only source packages
for 1.90.0, instead of having to go all the way back to 1.74.1. This is
a much more reasonable bootstrap path, and will enable us to drop older
Rust slots.
Signed-off-by: Matt Jolly <kangie <AT> gentoo.org>
dev-lang/rust/rust-1.90.0-r1.ebuild | 357 +++++++++++++++++++++++++++-
profiles/arch/amd64/package.use.stable.mask | 6 +-
2 files changed, 351 insertions(+), 12 deletions(-)
diff --git a/dev-lang/rust/rust-1.90.0-r1.ebuild
b/dev-lang/rust/rust-1.90.0-r1.ebuild
index 574b2a3a3429..4b90ea471c6c 100644
--- a/dev-lang/rust/rust-1.90.0-r1.ebuild
+++ b/dev-lang/rust/rust-1.90.0-r1.ebuild
@@ -6,6 +6,10 @@ EAPI=8
LLVM_COMPAT=( 20 )
PYTHON_COMPAT=( python3_{11..14} )
+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).
@@ -21,7 +25,7 @@ else
RUST_MIN_VER="$(ver_cut 1).$(($(ver_cut 2) - 1)).0"
fi
-inherit check-reqs estack flag-o-matic llvm-r1 multiprocessing optfeature \
+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
if [[ ${PV} = *9999* ]]; then
@@ -73,7 +77,8 @@ ALL_RUST_SYSROOTS=(
"${ALL_RUST_SYSROOTS[@]/#/rust_sysroots_}" )
LICENSE="|| ( MIT Apache-2.0 ) BSD BSD-1 BSD-2 BSD-4"
SLOT="${PV%%_*}" # Beta releases get to share the same SLOT as the eventual
stable
-IUSE="big-endian clippy cpu_flags_x86_sse2 debug dist doc llvm-libunwind lto
rustfmt rust-analyzer rust-src +system-llvm test ${ALL_LLVM_TARGETS[*]}
${ALL_RUST_SYSROOTS[*]}"
+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[*]}"
if [[ ${PV} = *9999* ]]; then
# These USE flags require nightly rust
@@ -111,6 +116,12 @@ BDEPEND="${PYTHON_DEPS}
)
test? ( dev-debug/gdb )
verify-sig? ( sec-keys/openpgp-keys-rust )
+ mrustc-bootstrap? (
+ ~dev-lang/mrustc-${MRUSTC_VERSION}
+ dev-build/cmake
+ sys-devel/gcc:*
+ )
+ !mrustc-bootstrap? ( ${RUST_DEPEND} )
"
DEPEND="
@@ -246,7 +257,16 @@ pkg_setup() {
die "Must enable LLVM_TARGETS=${cross_llvm_target}
matching CBUILD=${CBUILD} when cross-compiling"
fi
- rust_pkg_setup
+ if use mrustc-bootstrap; then
+ if ! tc-is-gcc; then
+ # USE="mrustc-bootstrap" reqires that the build
environment use GCC
+ export CC=${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
if use system-llvm; then
llvm-r1_pkg_setup
@@ -336,11 +356,13 @@ src_prepare() {
"${WORKDIR}/rust-patches-${RUST_PATCH_VER}/"
)
# Apply patches for bootstrapping with a particular Rust version
(RUST_SLOT).
- local
bootstrap_patchdir="${WORKDIR}/rust-patches-${RUST_PATCH_VER}/${RUST_SLOT}"
- if [[ -d "${bootstrap_patchdir}" ]]; then
- PATCHES+=(
- "${bootstrap_patchdir}"
- )
+ 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 lto && tc-is-clang && ! tc-ld-is-lld && ! tc-ld-is-mold; then
@@ -348,6 +370,14 @@ src_prepare() {
fi
default
+
+ 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
}
src_configure() {
@@ -396,9 +426,13 @@ src_configure() {
use miri && tools+=',"miri"'
fi
- 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"
+ 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
rust_target="$(rust_abi)"
rust_build="$(rust_abi "${CBUILD}")"
@@ -686,7 +720,308 @@ src_configure() {
echo
}
+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
+}
+
src_compile() {
+ use mrustc-bootstrap && mrustc_bootstrap
# -v will show invocations, -vv "very verbose" is overkill, -vvv "very
very verbose" is insane
RUST_BACKTRACE=1 "${EPYTHON}" ./x.py build -v
--config="${S}"/bootstrap.toml -j$(makeopts_jobs) || die
}
diff --git a/profiles/arch/amd64/package.use.stable.mask
b/profiles/arch/amd64/package.use.stable.mask
index 941ceb0b0ea1..165913af38aa 100644
--- a/profiles/arch/amd64/package.use.stable.mask
+++ b/profiles/arch/amd64/package.use.stable.mask
@@ -1,4 +1,4 @@
-# Copyright 1999-2025 Gentoo Authors
+# Copyright 1999-2026 Gentoo Authors
# Distributed under the terms of the GNU General Public License v2
# When you add an entry to the top of this file, add your name, the date, and
@@ -17,6 +17,10 @@
#--- END OF EXAMPLES ---
+# Matt Jolly <[email protected]> (2026-03-10)
+# mrustc is not yet stable on amd64, but we want bootstrap for Rust
+dev-lang/rust mrustc-bootstrap
+
# Paul Zander <[email protected]> (2025-12-01)
# no stable llvm-runtimes/offload
dev-cpp/eigen clang-cuda
