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matthiaskrgrmatthiaskrgr
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Rollup merge of rust-lang#135085 - knickish:m68k_unknown_none, r=workingjubilee
add m68k-unknown-none-elf target r? `@workingjubilee` The existing `m68k-unknown-linux-gnu` target builds `std` by default, requires atomics, and has a base cpu with an fpu. A smaller/more embedded target is desirable both to have a baseline target for the ISA, as well to make debugging easier for working on the llvm backend. Currently this target is using the `M68010` as the minimum CPU due, but as missing features are merged into the `M68k` llvm backend I am hoping to lower this further. I have been able to build very small crates using a toolchain built against this target (together with a later version of `object`) using the configuration described in the target platform-support documentation, although getting anything of substantial complexity to build quickly hits errors in the llvm backend
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‎compiler/rustc_target/src/spec/mod.rs

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@@ -1656,6 +1656,7 @@ supported_targets! {
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("loongarch64-unknown-linux-gnu", loongarch64_unknown_linux_gnu),
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("loongarch64-unknown-linux-musl", loongarch64_unknown_linux_musl),
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("m68k-unknown-linux-gnu", m68k_unknown_linux_gnu),
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("m68k-unknown-none-elf", m68k_unknown_none_elf),
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("csky-unknown-linux-gnuabiv2", csky_unknown_linux_gnuabiv2),
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("csky-unknown-linux-gnuabiv2hf", csky_unknown_linux_gnuabiv2hf),
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("mips-unknown-linux-gnu", mips_unknown_linux_gnu),

‎compiler/rustc_target/src/spec/targets/m68k_unknown_none_elf.rs

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use crate::abi::Endian;
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use crate::spec::{CodeModel, PanicStrategy, RelocModel, Target, TargetOptions};
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pub(crate) fn target() -> Target {
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let options = TargetOptions {
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cpu: "M68010".into(),
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max_atomic_width: None,
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endian: Endian::Big,
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// LLD currently does not have support for M68k
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linker: Some("m68k-linux-gnu-ld".into()),
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panic_strategy: PanicStrategy::Abort,
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code_model: Some(CodeModel::Medium),
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has_rpath: false,
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// should be soft-float
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llvm_floatabi: None,
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relocation_model: RelocModel::Static,
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..Default::default()
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};
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Target {
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llvm_target: "m68k".into(),
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metadata: crate::spec::TargetMetadata {
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description: Some("Motorola 680x0".into()),
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tier: Some(3),
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host_tools: Some(false),
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std: Some(false),
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},
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pointer_width: 32,
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data_layout: "E-m:e-p:32:16:32-i8:8:8-i16:16:16-i32:16:32-n8:16:32-a:0:16-S16".into(),
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arch: "m68k".into(),
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options,
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}
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}

‎src/doc/rustc/src/SUMMARY.md

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- [loongarch\*-unknown-linux-\*](platform-support/loongarch-linux.md)
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- [loongarch\*-unknown-none\*](platform-support/loongarch-none.md)
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- [m68k-unknown-linux-gnu](platform-support/m68k-unknown-linux-gnu.md)
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- [m68k-unknown-none-elf](platform-support/m68k-unknown-none-elf.md)
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- [mips64-openwrt-linux-musl](platform-support/mips64-openwrt-linux-musl.md)
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- [mipsel-sony-psx](platform-support/mipsel-sony-psx.md)
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- [mips\*-mti-none-elf](platform-support/mips-mti-none-elf.md)

‎src/doc/rustc/src/platform-support.md

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[`i686-wrs-vxworks`](platform-support/vxworks.md) | ✓ | | [^x86_32-floats-return-ABI]
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[`loongarch64-unknown-linux-ohos`](platform-support/openharmony.md) | ✓ | | LoongArch64 OpenHarmony
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[`m68k-unknown-linux-gnu`](platform-support/m68k-unknown-linux-gnu.md) | ? | | Motorola 680x0 Linux
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[`m68k-unknown-none-elf`](platform-support/m68k-unknown-none-elf.md) | | | Motorola 680x0
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`mips-unknown-linux-gnu` | ✓ | ✓ | MIPS Linux (kernel 4.4, glibc 2.23)
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`mips-unknown-linux-musl` | ✓ | | MIPS Linux with musl 1.2.3
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`mips-unknown-linux-uclibc` | ✓ | | MIPS Linux with uClibc

‎src/doc/rustc/src/platform-support/m68k-unknown-none-elf.md

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# m68k-unknown-none-elf
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**Tier: 3**
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Bare metal Motorola 680x0
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## Designated Developers
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* [@knickish](https://github.com/knickish)
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## Requirements
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This target requires an m68k build environment for cross-compilation which
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is available on Debian, Debian-based systems, openSUSE, and other distributions.
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On Debian-based systems, it should be sufficient to install a g++ cross-compiler for the m68k
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architecture which will automatically pull in additional dependencies such as
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the glibc cross development package:
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```sh
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apt install g++-m68k-linux-gnu
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```
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Binaries can be run using QEMU user emulation. On Debian-based systems, it should be
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sufficient to install the package `qemu-user-static` to be able to run simple static
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binaries:
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```text
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# apt install qemu-user-static
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```
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To run more complex programs, it will be necessary to set up a Debian/m68k chroot with
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the help of the command `debootstrap`:
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```text
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# apt install debootstrap debian-ports-archive-keyring
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# debootstrap --keyring=/usr/share/keyrings/debian-ports-archive-keyring.gpg --arch=m68k unstable debian-68k http://ftp.ports.debian.org/debian-ports
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```
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This chroot can then seamlessly entered using the normal `chroot` command thanks to
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QEMU user emulation:
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```text
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# chroot /path/to/debian-68k
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```
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To get started with native builds, which are currently untested, a native Debian/m68k
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system can be installed either on real hardware such as 68k-based Commodore Amiga or
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Atari systems or emulated environments such as QEMU version 4.2 or newer or ARAnyM.
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ISO images for installation are provided by the Debian Ports team and can be obtained
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from the Debian CD image server available at:
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[https://cdimage.debian.org/cdimage/ports/current](https://cdimage.debian.org/cdimage/ports/current/)
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Documentation for Debian/m68k is available on the Debian Wiki at:
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[https://wiki.debian.org/M68k](https://wiki.debian.org/M68k)
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Support is available either through the `debian-68k` mailing list:
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[https://lists.debian.org/debian-68k/](https://lists.debian.org/debian-68k/)
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or the `#debian-68k` IRC channel on OFTC network.
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## Building
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At least llvm version `19.1.5` is required to build `core` and `alloc` for this target, and currently the gnu linker is required, as `lld` has no support for the `m68k` architecture
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## Cross-compilation
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This target can be cross-compiled from a standard Debian or Debian-based, openSUSE or any
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other distribution which has a basic m68k cross-toolchain available.
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## Testing
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Currently there is no support to run the rustc test suite for this target.
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## Building Rust programs
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Recommended `.cargo/config.toml`:
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```toml
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[unstable]
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build-std = ["panic_abort", "core", "alloc"]
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[target.m68k-unknown-none-elf]
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# as we're building for ELF, the m68k-linux linker should be adequate
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linker = "m68k-linux-gnu-ld"
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# the mold linker also supports m68k, remove the above line and uncomment the
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# following ones to use that instead
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# linker = "clang"
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# rustflags = ["-C", "link-arg=-fuse-ld=/path/to/mold/binary"]
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```
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Rust programs can be built for this target using:
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```sh
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cargo build --target m68k-unknown-none-elf
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```
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Very simple programs can be run using the `qemu-m68k-static` program:
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```sh
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qemu-m68k-static your-code
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```
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For more complex applications, a chroot or native m68k system is required for testing.

‎src/tools/build-manifest/src/main.rs

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"loongarch64-unknown-none",
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"loongarch64-unknown-none-softfloat",
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"m68k-unknown-linux-gnu",
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"m68k-unknown-none-elf",
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"csky-unknown-linux-gnuabiv2",
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"csky-unknown-linux-gnuabiv2hf",
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"mips-unknown-linux-gnu",

‎tests/assembly/targets/targets-elf.rs

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//@ revisions: m68k_unknown_linux_gnu
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//@ [m68k_unknown_linux_gnu] compile-flags: --target m68k-unknown-linux-gnu
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//@ [m68k_unknown_linux_gnu] needs-llvm-components: m68k
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//@ revisions: m68k_unknown_none_elf
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//@ [m68k_unknown_none_elf] compile-flags: --target m68k-unknown-none-elf
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//@ [m68k_unknown_none_elf] needs-llvm-components: m68k
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//@ revisions: mips64_openwrt_linux_musl
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//@ [mips64_openwrt_linux_musl] compile-flags: --target mips64-openwrt-linux-musl
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//@ [mips64_openwrt_linux_musl] needs-llvm-components: mips

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