I have installed both nightly and stable rust toolchains and make some -Z ... compile flags for nightly, but the stable rust can't recognize it and stops compiling; is there a way or a cargo directive to conditionally switch between nightly/stable rust compiler.
In .cargo/config.toml file
[build]
rustflags = [
"-C...",
"-Z...",
]
For nightly rust read -Z and -C flags, for stable rust only read -C or ignore -Z completely. So that, we can use cargo +stable/+nightly build without modify config.toml file every time.
Thanks Ruster ~
I don't think it's possible to specify rustc unstable feature inside config.toml but you can specify cargo unstable feature. It could be nice to have.
You could create a "nightly" directory:
cd my_rust_project
mkdir my_nightly_project
cd my_nightly_project
rustup override set nightly
Then using merge feature of config file of cargo you create you can override the global config using a my_nightly_project/.cargo/config.toml file.
Consider using alias instead.
Related
I'm specifying the -Cpanic=abort and -Zbuild-std=panic_abort when compiling. Why does the linker still say it needs libunwind to compile a program?
I'm experimenting with various ways to cross-compile Rust programs as small as possible (using the min-sized-rust repo as a reference). Right now I'm trying to compile the powerpc64-unknown-linux-musl target and I'm stuck on trying to remove a dependency on libunwind.
Here's my setup:
# 1. Install the Rust std source code
rustup component add rust-src --toolchain nightly
# 2. Setup a simple rust repo
cargo init testing
cd testing
# 3. Download a musl toolchain
wget https://musl.cc/powerpc64-linux-musl-cross.tgz
tar xzf powerpc64-linux-musl-cross.tgz
# 4. Try to compile the project (options on the command line instead of in files for
# maximum obviousness).
# RUSTFLAGS:
# -Cpanic=abort - abort immediately on panic
# -Clink-self-contained=no - don't use rustc's builtin libraries and objects (this
# is needed because powerpc64-unknown-linux-musl is a tier 3 target)
# -Clink-arg=--sysroot and -Clink-arg=/path/to/sysroot - pass the option to the linker
# to specify the sysroot of cross-compilation toolchain
# Cargo options:
# --config target.<triple>.linker - specify the linker to use
# -Zbuild-std=std,panic_abort - build the standard library from source. Specify
# panic_abort to make the abort on panic work
RUSTFLAGS="-Cpanic=abort -Clink-self-contained=no -Clink-arg=--sysroot -Clink-arg=powerpc64-linux-musl-cross/powerpc64-linux-musl/" \
cargo +nightly build \
--config "target.powerpc64-unknown-linux-musl.linker=\"powerpc64-linux-musl-cross/bin/powerpc64-linux-musl-gcc\"" \
--target powerpc64-unknown-linux-musl -Zbuild-std=panic_abort,std --release
This fails with the following error:
error: linking with `/home/user/Projects/testing/powerpc64-linux-musl-cross/bin/powerpc64-linux-musl-gcc` failed: exit status: 1
<output snipped>
= note: /home/user/Projects/testing/powerpc64-linux-musl-cross/bin/../lib/gcc/powerpc64-linux-musl/11.2.1/../../../../powerpc64-linux-musl/bin/ld: cannot find -lunwind
From min-size-rust repository:
"Even if panic = "abort" is specified in Cargo.toml, rustc will still include panic strings and formatting code in final binary by default. An unstable panic_immediate_abort feature has been merged into the nightly rustc compiler to address this.
To use this, repeat the instructions above to use build-std, but also pass the following -Z build-std-features=panic_immediate_abort option."
Still, you will get "cannot find -lunwind", because the linker still uses libunwind, even though it's truly unneeded,why! I do not know, maybe it's a bug.(Maybe someone with fair knowledge about linkers can easily solve that.I tried a naive solution which is "cargo .... --verbose", copy , remove "libunwind" then relinking which failed)
I verified that is indeed the missing piece by build from source(--target=x86_64-unknown-linux-musl) AND using an old simple trick which is "touch libunwind.a" in the "self-contained" directory inside a target lib folder.(because the linker would still use it even though it's now truly unneeded, then I gave him a dummy libunwind.a)
In your case, I really tried to build it to your target until I got a headache, but couldn't and stopped, but here is possible solutions:
Giving that you're using "-Z build-std-features=panic_immediate_abort"
-If you can custom the linking process, then solve it (until what seems to be a bug is solved)
-Create a dummy(empty) libunwind.a where it should be in your toolchain
The output of rustup target list --toolchain nightly does not contain x86_64-apple-ios-macabi, even though it is in src/librustc_target on the Rust master branch.
How do I build for Mac Catalyst / x86_64-apple-ios-macabi?
The x86_64-apple-ios-macabi target is available on the nightly (5c5b8afd8 2019-11-16) compiler. Just because a target is available does not mean that the standard library and friends are compiled or available to rustup:
% rustc +nightly --print target-list | grep macabi
x86_64-apple-ios-macabi
Rust has a tier system (which is the subject of a proposed RFC). This target is so new it's not even listed on the tier list, but it's undoubtedly going to be tier 3. Tier 2.5 says (emphasis mine):
Tier 2.5 platforms can be thought of as "guaranteed to build", but without builds available through rustup
In the meantime, you will need to build your own libcore / libstd from source. I don't have the time nor ability to actually test that the compilation works, but something like these choices are the general starting path:
build-std
The unstable -Z build-std flag can be used to build the standard library:
% cargo +nightly build -Z build-std --target x86_64-apple-ios-macabi
Xargo
Building the standard library can be done using the xargo tool.
% rustup override set nightly
info: using existing install for 'nightly-x86_64-apple-darwin'
info: override toolchain for '/private/tmp/example' set to 'nightly-x86_64-apple-darwin'
nightly-x86_64-apple-darwin unchanged - rustc 1.41.0-nightly (5c5b8afd8 2019-11-16)
% cat > Xargo.toml
[target.x86_64-apple-ios-macabi.dependencies.std]
# features = ["jemalloc"] # Whatever is appropriate
% xargo build --target x86_64-apple-ios-macabi
# Iterate until libcore and libstd compile and work for your platform
#shepmaster 's answer is correct. In detail, you have to:
Install Xargo:
cargo install xargo
cd in your project
use the nighly build:
rustup override set nightly
create the Xargo.toml file with content:
[target.x86_64-apple-ios-macabi.dependencies.std]
In your projects Cargo.toml, make sure the [profile.release] section contains panic = "abort". If it does not, add it.
When building the project, use xargoinstead of cargo.
Shepmaster's answer is a little outdated. Cargo now supports the -Zbuild-std command. Using it, you can target any of the targets that rustc itself supports even if they aren't listed on rustup +nightly target list. Simply:
rustc +nightly --print target-list
and
cargo +nightly build -Z build-std --target x86_64-apple-ios-macabi
should be enough now. You don't need xargo to build the standard lib anymore.
If you have an old installation of rust, you might need to remove old nightly (or at least for me it fails to update nightly):
rustup toolchain remove nightly
rustup update
rustup toolchain install nightly
The program I'm writing runs much faster when the -C target-cpu=native flag is passed to rustc. I want to give users a simple, platform-independent way to enable this when compiling, so I added a Cargo feature cpu_native = [] in Cargo.toml and created this Cargo config in my project:
[target.'cfg(cpu_native)']
rustflags = ["-C", "target-cpu=native"]
However, this has no effect on my program, and passing --features cpu_native to Cargo does not even trigger a recompile. Changing to the following Cargo config does force re-compilation with faster instructions:
[build]
rustflags = ["-C", "target-cpu=native"]
However, this will compile with target-cpu=native with the default Cargo features, which was not what I wanted. From the Cargo book, what I want seems to be possible, but I don't see what I'm doing wrong.
I don't think this is supported (yet?). I enhanced Cargo to print out what config flags are checked against when resolving:
[
Name("debug_assertions"),
Name("proc_macro"),
KeyPair("target_arch", "x86_64"),
KeyPair("target_endian", "little"),
KeyPair("target_env", ""),
KeyPair("target_family", "unix"),
KeyPair("target_os", "macos"),
KeyPair("target_pointer_width", "64"),
Name("unix"),
]
[target.'cfg(cpu_native)']
This is the incorrect syntax for a Cargo feature; it would normally be cfg(feature = "cpu_native").
I'm trying to run my tests with nightly Rust using Windows Powershell. I run cargo test in the directory, and I get
Compiling rustcraft v0.1.0 (file:///C:/Users/Phoenix/Desktop/Rust/rustcraft)
error[E0554]: #![feature] may not be used on the stable release channel
--> C:\Users\Phoenix\Desktop\Rust\rustcraft\src\main.rs:1:1
|
1 | #![feature(integer_atomics)]
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error[E0554]: #![feature] may not be used on the stable release channel
--> C:\Users\Phoenix\Desktop\Rust\rustcraft\src\main.rs:2:1
|
2 | #![feature(collections)]
| ^^^^^^^^^^^^^^^^^^^^^^^^
Obviously, I have to tell Cargo to compile it on the nightly channel, but how? I can't find any reference to specifying a channel in the help section, or any website I've found.
The command line solution may help you to configure your IDE:
cargo +nightly test
Provided, of course, that you have the nightly channel installed. If not, perhaps install it with rustup install nightly (no need to switch to it, but check you're still on stable: rustup show).
The +<toolchain> functionality comes from rustup, the Rust toolchain manager. It works for both cargo +<toolchain> as well as rustc +<toolchain>.
In addition, you can use
rustup run <toolchain> <any arbitrary command goes here>
Since your project requires nightly features, you can change into the directory and run rustup override set <toolchain> to always use the nightly toolchain in that directory.
Create a file called rust-toolchain in your directory containing the name of the toolchain required (e.g. nightly). This has the safe effect as an override, but can be committed to source control.
See also:
Is it possible to have multiple coexisting Rust installations?
I am using the include_bytes! macro to compile a GLSL shader into a rust program. It seems that Cargo is unaware of this however: when I modify just the shader file and test it with cargo run the updated file is not compiled in. Manually touching the .rs file that includes the shader does work.
Do I need to add something to my Cargo.toml to explictly state this dependency?
Version info:
$ rustc --version && cargo --version
rustc 1.0.0-nightly (ecf8c64e1 2015-03-21) (built 2015-03-22)
cargo 0.0.1-pre-nightly (e689383 2015-03-16) (built 2015-03-16)
This has been fixed in rustc: https://github.com/rust-lang/rust/pull/24423
Cargo has no way currently to add a file to the list of 'watched' files for changes. It won't know about files included with include_bytes! because that would involve special-casing that macro specifically.