Cross-Compiling for Raspbarry Pi...

Aiyarree

Hi everyone :-)

i just tried to find the equivalent to
gcc-4.7-multilib-arm-linux-gnueabihf
But without any luck. (This is what the package is named on apt/ubuntu)

Could somebody please give me a hint howto compile something for Raspbarry/ARM?

Thanks :-)

DataDrake

I think arm-none-eabi-gcc should do the trick.

Aiyarree

just tried it.

error: Could not create LLVM TargetMachine for triple: armv7-unknown-linux-gnueabihf: No available targets are compatible with triple "armv7-unknown-linux-gnueabihf"

Think this package is good for something else.

In addition - i have no idea about architecture of chips but Raspi is Cortex A and in the package only Cortex-M and R are mentioned.

DataDrake

Aiyarree Ah, for some reason I thought we had the A series enabled. You can grab a prebuilt cross-toolchain from ARM directly: https://developer.arm.com/tools-and-software/open-source-software/developer-tools/gnu-toolchain/gnu-a/downloads

Aiyarree

Ok... first of all: Thank you for the information.

But to be honest this is getting beyond my understandings.
The error remains the same and all world only refers to

ubuntus sudo apt-get install gcc-4.7-multilib-arm-linux-gnueabihf
and link it with this lines in the .cargo/config:

[build]
target = "armv7-unknown-linux-gnueabihf"
[target.armv7-unknown-linux-gnueabihf]
linker = "arm-linux-gnueabihf-gcc-4.7"

So i tried to redirect the linker to
/directory/arm-none-linux-gnueabihf-gcc
or /directory/arm-none-linux-gnueabihf-gcc-9.2.1

Absolute nothing changes. Something tells me that this whole "none" stuff is the wrong horse.
Also the versioning "9.2.1" seems to be a wrong direction as it is quiet far away from "4.7".

I think i will put this on side till someone with more knowledge can bring light to this.
I just tried to have some fun with programming and stumbled over a dragons tail ;-)

Aiyarree

Ok, i did it.

Bad news first:
I was not able to get it working with the rust-stuff from the repository.
I did not get to deep into this but it seems something is missing.

So first of all, you have to install rust with the script from their Homepage:
https://www.rust-lang.org/learn/get-started
I do not want to go too much into Details here. It is very straight forward.
Depending on your shell it is your part to get the PATH-stuff done.
I think for bash it is done automaticaly. With fish i had to do some extra work in my config.fish

As i have a raspberry 4 i use the 64bit-ubuntu-server (headless).
Therefor i need the 64bit ARM architecture to build my stuff:
rustup target add aarch64-unknown-linux-gnu

If you want to go the 32bit route i am pretty sure:
rustup target add armv7-unknown-linux-gnueabihf
gets the job done. But i have not tested it.

Now we need a Linker.
You might find other stuff but this one worked for me out of the box:
https://releases.linaro.org/components/toolchain/binaries/
gcc-linaro-5.5.0-2017.10-x86_64_aarch64-linux-gnu.tar.xz
There is newer stuff available. So there is room for experiments.

And if you are still on the 32bit road:
gcc-linaro-5.5.0-2017.10-x86_64_arm-linux-gnueabihf.tar.xz
should be a good pointer into the right direction.

Again you have to decide where to put the thing and how to get it into the PATH.
This time even with bash you have something to do ;-)

Now we are pretty much done with picking up tools and actually can have some fun.
I am sure you can get away with giving rustc the target and the linker manually.
But because i am lazy i put this lines into my .cargo/config. Feel free to create it if it does not exist:

[build] target = "aarch64-unknown-linux-gnu" [target.aarch64-unknown-linux-gnu] linker = "aarch64-linux-gnu-gcc"

Again with 32bit stuff you have to adjust this lines accordingly.

And if you want to have even more fun with the Raspberry you can add:
[dependencies] rust_gpiozero = "0.2.0"
to your Cargo.toml and let the pins on the raspberry do a little dance for you.