rustc +nightly -Z unstable-options --print target-spec-json --target=mipsel-unknown-linux-gnu- "env": "gnu",
+ "env": "uclibc",The impact of this is a bit complicated.
On the one hand, the nix package is broken as heck on target_env="uclibc".
nix imports a bunch of libc stuff which is just plain missing on uclibc, and thus fails to build.
(TODO: fix nix?)
On the other hand, target_env="gnu" is wrong and breaks std::env::args()!
Specifically, init no longer calls really_init.
uclibc does call .init_array.* as defined by rust's stdlib,
but the parameters are different or bogus!
Specifically:
argcis either uninitialized or a pointer (large varying values per run)argvis either uninitialized or 0/nullptr (only ever observed to be 0 on my RG350M)_envp... heck if I know, I didn't check.
- "features": "+mips32r2,+softfloat",
+ "features": "+mips32r2",Apparently gcw0 uses hard floats, whereas the default mipsel-unknown-linux-musl target uses soft floats.
- "is-builtin": true,
+ "is-builtin": false,Duh.
+ "linker": "/opt/gcw0-toolchain/usr/bin/mipsel-linux-gcc",gcw0-toolchain binaries assume it's been installed to /opt/gcw0-toolchain, so we might as well make the target assume the same.
- "llvm-target": "mipsel-unknown-linux-gcc",
+ "llvm-target": "mipsel-gcw0-linux-uclibc",Seems... more accurate, based on gcw0-toolchain layout? Not entirely sure about the impact of changing "vendor" from "unknown' to "gcw0".
- "vendor": "unknown"
+ "vendor": "gcw0"Ditto
Necessary to cause xargo to build std.
[target.mipsel-gcw0-linux-uclibc.dependencies.std]
features = []rustc --target=mipsel-unknown-linux-gnu --print target-features
rustc +nightly -Z unstable-options --print target-spec-json --target=mipsel-unknown-linux-gnu| Var | Value | Why |
|---|---|---|
RUST_TARGET_PATH |
workspace | xargo can't find target spec json files otherwise (workspace related?) |
RUSTUP_TOOLCHAIN |
nightly-2020-06-15 |
xargo +nightly-2020-06-15 sadly doesn't work |
PATH |
/opt/gcw0-toolchain/usr/bin |
Less necessary now that we have a target json spec |
XARGO_RUST_SRC |
~/.rustup/toolchains/nightly-2020-06-15-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/src |
Make a copy of that folder and modify it if you want to tweak std |
- https://rust-embedded.github.io/embedonomicon/custom-target.html
- https://doc.rust-lang.org/rustc/targets/custom.html
- http://www.gcw-zero.com/develop
- http://www.gcw-zero.com/updates
- https://boards.dingoonity.org/gcw-development/gcw-zero-toolchain-for-windows-(cygwin)-2013-10-04/
- http://www.gcw-zero.com/files/etnaviv-2013-10-04.html
- http://www.gcw-zero.com/updates
- https://github.com/laanwj/mesatest_gles
- https://github.com/laanwj/mesatest_gles/tree/master/Common
- https://github.com/laanwj/mesatest_gles/blob/master/Common/esUtil.c
- https://www.khronos.org/registry/EGL/sdk/docs/man/html/eglIntro.xhtml
- https://www.khronos.org/registry/EGL/specs/eglspec.1.4.pdf
- https://docs.rs/egl/0.2.7/egl/