IRIX GCC

An IRIX 6.5 port of GCC, forked from rust-lang/gcc — the GCC 17 development trunk that also carries the patched libgccjit that rustc_codegen_gcc needs. One codebase serves both the IRIX 6.5 rebuild and the Rust backend for the future IRIX 7 operating system.

Target: mips-sgi-irix6.5 — big-endian MIPS III/IV, ELF32, with the o32, n32 and n64 ABIs.

What this fork provides

• Cross compiler — runs on a modern host (x86-64 Linux) and emits IRIX binaries. This is the toolchain the IRIX 6.5 rebuild uses. Driven by the project's scripts/build-toolchain.sh --gcc fork.
• Native IRIX GCC (in progress) — a GCC that itself runs on IRIX, produced by a Canadian cross (--build=x86_64-linux --host=mips-sgi-irix6.5 --target=mips-sgi-irix6.5) and installed on the guest. See issue #15.
• A patched libgccjit — the Rust codegen backend, built from the same tree with --enable-languages=…,jit --enable-host-shared.

What's included

Language	Frontend	Target runtime	Status
C	cc1	libgcc	works (o32/n32/n64)
C++	cc1plus	libstdc++	works (IRIX OS layer ported)
Fortran	f951	libgfortran	works (IRIX C99 gap fixed — issue #157)
JIT	libgccjit	n/a (host)	works — the Rust backend
Go	go1	libgo	in progress — issue #153
Objective-C / Obj-C++	cc1obj/cc1objplus	libobjc	not enabled — issue #154
Modula-2	cc1gm2	libgm2	not enabled — issue #154
D	d21	libphobos	not enabled — issue #154
Ada	gnat1	libgnat	not enabled — issue #154
COBOL	cob1	libgcobol	not available (x86-64/AArch64 only) — issue #154
Rust	gccrs (experimental)	—	not used — the project uses rustc + rustc_codegen_gcc

Also built: libgcc, libstdc++, libgfortran, libquadmath, libgccjit, startfiles and the IRIX crt objects.

Build

Do not build in this tree directly. The project drives the build, pins the sources, applies the series and verifies the result:

git clone https://github.com/irix7/project
cd project
nix develop --command bash -c \
  'scripts/build-toolchain.sh --gcc fork --languages c,c++,fortran,jit \
     --sysroot /path/to/irix-6.5.7m-sysroot'
scripts/verify-toolchain.sh \
  --prefix .scratch/toolchain-17.0.0/prefix --gcc-version 17.0.0

You need GNU Nix and a captured IRIX 6.5.7m sysroot (see the project's docs/oracle.md). The cross is paired with the project's IRIX-patched binutils series. No SGI material is distributed here or by the build.

Status — what works, and what does not yet

Works: C, C++, Fortran and libgccjit; o32 and n32 (and n64 build/link); dynamic and static links against the captured sysroot; verify-toolchain.sh passes.

Not yet:

• libstdc++ C++23 std module on IRIX — it now builds, but re-exports only the parts IRIX's pre-C99 headers provide: the C99 math/stdio/stdlib additions are guarded out just as <cmath>/<cstdio>/<cstdlib> guard them on a non-C99 target. issue #157
• Go / gccgo — the frontend builds; the libgo IRIX runtime is being restored. issue #153
• Objective-C, Modula-2, D, Ada, COBOL — not enabled for IRIX. issue #154
• n64 — builds and links, but the runtime is not exercised (it cannot run on the project's 32-bit guest). issue #155
• libatomic — disabled for the sysroot build, interim. issue #150
• Native IRIX GCC — Canadian cross not built yet. issue #15
• Rust backend — rustc_codegen_gcc not yet exercised against this fork's libgccjit. issue #156

Contributing

Pull requests are welcome — IRIX 6.5 build fixes, new frontend/runtime ports (Go, Objective-C, Modula-2), and GCC 17 forward-port fixes especially.

• Keep the IRIX port as commits on master (the series is the source of truth), upstream style, one concern per commit, each referencing its tracking issue in irix7/project.
• Match upstream conventions; run the relevant GCC tests where practical.
• The project publishes no SGI-derived material: don't paste IRIX source, headers or binaries into patches or the README.

The IRIX port

The port is a series of commits on master, not a branch:

• IRIX target restoration: config, multilibs and startfiles
• IRIX MIPS target macros and headers
• IRIX MIPS codegen and bootstrap adjustments; libgcc/libgomp runtime
• IRIX configure changes; libstdc++ IRIX OS layer
• GCC 17 forward-port fixes: the LRA reload guard (#149), IRIX_USING_GNU_LD via ld_flavor (#150), n64 sysroot paths (#151), the libstdc++ namespace/ctype files (#152), and the libgo IRIX OS layer (#153)

Upstream, licence and related

• Fork of: https://github.com/rust-lang/gcc; upstream GCC: https://gcc.gnu.org/git/gcc.git
• Licence: GPL-3.0 with the GCC Runtime Library Exception (COPYING3, COPYING.RUNTIME)
• Project hub — patch series, build scripts, docs, decisions and issues: https://github.com/irix7/project