dev-lang/rust: Drop our custom package in favour of upstream Gentoo's

It is not clear why this was forked originally. One reason was to avoid
the sys-apps/lsb-release dependency, but it probably wasn't just that.
It seems likely that the upstream package did not support cross targets
at the time. Now it does.

It appears that LTO was previously enabled by us following Gentoo rather
than through an explicit decision. They now disable it by default, so we
do likewise. It previously used "fat" LTO, which makes Rust especially
slow to build and reportedly made rustc slower than with "thin" LTO!
There seems little benefit in using thin LTO given that we rebuild Rust
almost as much as the packages that use it, plus we don't enable LTO
anywhere else.

We still avoid rustdoc to keep the size down using INSTALL_MASK. This
isn't as good as not building it in the first place, but this alone
isn't worth keeping a fork.

Cross targets are now handled via the admittedly experimental
RUST_CROSS_TARGETS support. This has been in place for a while, and I
think it is fairly widely used now. If it does disappear, it would
almost certainly be for something even better.

This also updates Rust from 1.80.0 to 1.80.1.

Signed-off-by: James Le Cuirot <[email protected]>

Author: chewi

.github/workflows/portage-stable-packages-list

@@ -207,6 +207,7 @@ dev-lang/perl
 dev-lang/python
 dev-lang/python-exec
 dev-lang/python-exec-conf
+dev-lang/rust
 dev-lang/swig
 dev-lang/tcl
 dev-lang/yasm
@@ -688,6 +689,7 @@ virtual/perl-Getopt-Long
 virtual/perl-IO
 virtual/perl-Unicode-Collate
 virtual/pkgconfig
+virtual/rust
 virtual/service-manager
 virtual/ssh
 virtual/tmpfiles

.github/workflows/rust-apply-patch.sh

@@ -105,7 +105,7 @@ cat <<EOF
 # stage1 packages aren't published, save in tmp
 pkgcache_path: ${TEMPDIR}/stage1-${ARCH}-packages
 update_seed: yes
-update_seed_command: --exclude cross-*-cros-linux-gnu/* --exclude dev-lang/rust --ignore-world y --ignore-built-slot-operator-deps y @changed-subslot
+update_seed_command: --exclude cross-*-cros-linux-gnu/* --exclude dev-lang/rust --exclude virtual/rust --ignore-world y --ignore-built-slot-operator-deps y @changed-subslot
 EOF
 catalyst_stage_default 1
 }

.github/workflows/rust-release-main.yaml

@@ -20,6 +20,6 @@ for cross_chost in $(get_chost_list); do
     echo "Building cross toolchain for ${cross_chost}"
     PKGDIR="$(portageq envvar PKGDIR)/crossdev" \
         install_cross_toolchain "${cross_chost}" ${clst_myemergeopts}
-    PKGDIR="$(portageq envvar PKGDIR)/crossdev" \
-        install_cross_rust "${cross_chost}" ${clst_myemergeopts}
 done
+
+PKGDIR="$(portageq envvar PKGDIR)/crossdev" install_cross_rust ${clst_myemergeopts}

build_library/catalyst.sh

@@ -410,14 +410,6 @@ install_cross_toolchain() {
     else
         echo "Installing existing binaries"
         "${sudo[@]}" emerge "${emerge_flags[@]}" "${emerge_atoms[@]}"
-        if [ "${cbuild}" = "x86_64-pc-linux-gnu" ] && [ "${cross_chost}" = aarch64-cros-linux-gnu ] && \
-           [ ! -d /usr/lib/rust-*/rustlib/aarch64-unknown-linux-gnu ] && [ ! -d /usr/lib/rustlib/aarch64-unknown-linux-gnu ]; then
-          # If no aarch64 folder exists, warn about the situation but don't compile Rust here or download it as binary package
-          echo "WARNING: No aarch64 cross-compilation Rust libraries found!"
-          echo "In case building fails, make sure the old Rust version is deleted with: sudo emerge --unmerge virtual/rust dev-lang/rust"
-          echo "Then install it again with: sudo emerge ${emerge_flags[@]} virtual/rust"
-          echo "This will download the binary package or build from source."
-        fi
     fi
 
     # Setup environment and wrappers for our shiny new toolchain
@@ -471,22 +463,22 @@ install_cross_libs() {
 }
 
 install_cross_rust() {
-    local cross_chost="$1"; shift
-    local emerge_flags=( "$@" --binpkg-respect-use=y --update )
-    local cbuild="$(portageq envvar CBUILD)"
-
     # may be called from either catalyst (root) or upgrade_chroot (user)
     local sudo=("env")
     if [[ $(id -u) -ne 0 ]]; then
         sudo=("sudo" "-E")
     fi
 
-    if [ "${cbuild}" = "x86_64-pc-linux-gnu" ] && [ "${cross_chost}" = "aarch64-cros-linux-gnu" ]; then
-        echo "Building Rust for arm64"
-        # If no aarch64 folder exists, try to remove any existing Rust packages.
-        [ ! -d /usr/lib/rustlib/aarch64-unknown-linux-gnu ] && ("${sudo[@]}" emerge --unmerge dev-lang/rust || true)
-        "${sudo[@]}" emerge "${emerge_flags[@]}" dev-lang/rust
-    fi
+    echo "Installing dev-lang/rust with (potentially outdated) cross targets."
+    "${sudo[@]}" emerge "${emerge_flags[@]}" --binpkg-respect-use=y --update dev-lang/rust
+
+    [[
+       -d /usr/lib/rustlib/x86_64-unknown-linux-gnu &&
+       -d /usr/lib/rustlib/aarch64-unknown-linux-gnu
+    ]] && return
+
+    echo "Rebuilding dev-lang/rust with updated cross targets."
+    "${sudo[@]}" emerge "${emerge_flags[@]}" --usepkg=n dev-lang/rust
 }
 
 # Update to the latest binutils profile for a given CHOST if required

build_library/catalyst_sdk.sh

@@ -0,0 +1 @@
+- SDK: Rust ([1.80.1](https://github.com/rust-lang/rust/releases/tag/1.80.1))

build_library/toolchain_util.sh

@@ -0,0 +1,6 @@
+INSTALL_MASK+=" *rustdoc*"
+I_KNOW_WHAT_I_AM_DOING_CROSS=1
+
+RUST_CROSS_TARGETS=(
+	$(aarch64-cros-linux-gnu-gcc --version >/dev/null && echo "AArch64:aarch64-unknown-linux-gnu:aarch64-cros-linux-gnu")
+)

changelog/updates/2024-08-15-rust-1.80.1-update.md

@@ -49,7 +49,7 @@
 =dev-lang/python-3.11.9_p1 ~amd64
 
 # Accept unstable host Rust compilers.
-=dev-lang/rust-1.80.0 ~amd64 ~arm64
+=dev-lang/rust-1.80.1 ~amd64 ~arm64
 
 # Needed by arm64-native SDK.
 =dev-lang/yasm-1.3.0-r1 ~arm64
@@ -106,4 +106,4 @@ dev-util/catalyst ~amd64 ~arm64
 =sys-cluster/ipvsadm-1.31-r1 ~arm64
 
 # Accept unstable host Rust compilers.
-=virtual/rust-1.80.0 ~amd64 ~arm64
+=virtual/rust-1.80.1 ~amd64 ~arm64