How to force rust target in firefox build

[John Frankish]

I'm trying to compile firefox natively on an RPi4 running tinycorelinux piCore.

The configure phase fails because it tries to use arm-unknown-linux-gnueabihf as the rust target instead of armv7-unknown-linux-gnueabihf.

If I try the rust test manually, i.e.:

/usr/local/bin/rustc --crate-type staticlib --target=armv7-unknown-linux-gnueabihf -o /tmp/conftest.rlib /tmp/conftest.rs

..it passes.

Is there a way to force the rust target?

----

./mach build
...
0:07.54 checking for host system type... armv7l-unknown-linux-gnueabihf
0:07.54 checking for target system type... armv7l-unknown-linux-gnueabihf
...
0:16.71 checking for rust target triplet...
0:16.71 DEBUG: Creating `/tmp/conftestg7rtgcch.rs` with content:
0:16.71 DEBUG: | pub extern fn hello() { println!("Hello world"); }
0:16.71 DEBUG: Executing: `/usr/local/bin/rustc --crate-type staticlib --target=arm-unknown-linux-gnueabihf -o /tmp/conftestmw0yudfu.rlib /tmp/conftestg7rtgcch.rs`
0:16.72 DEBUG: The command returned non-zero exit status 1.
0:16.72 DEBUG: Its error output was:
0:16.72 DEBUG: | error[E0463]: can't find crate for `std`
0:16.72 DEBUG: | |
0:16.72 DEBUG: | = note: the `arm-unknown-linux-gnueabihf` target may not be installed
0:16.72 DEBUG: |
0:16.73 DEBUG: | error: aborting due to previous error
0:16.73 DEBUG: |
0:16.73 DEBUG: | For more information about this error, try `rustc --explain E0463`.
0:16.73 ERROR: Cannot compile for armv7l-unknown-linux-gnueabihf with /usr/local/bin/rustc
0:16.73 The target may be unsupported, or you may not have
0:16.73 a rust std library for that target installed. Try:
0:16.73 rustup target add arm-unknown-linux-gnueabihf
0:16.89 *** Fix above errors and then restart with\
0:16.89 "./mach build"
0:16.89 make: *** [client.mk:115: configure] Error 1

[Mike Hommey]

On Wed, Jul 01, 2020 at 05:34:16PM +0000, John Frankish wrote:
> I'm trying to compile firefox natively on an RPi4 running tinycorelinux piCore.
>
> The configure phase fails because it tries to use arm-unknown-linux-gnueabihf as the rust target instead of armv7-unknown-linux-gnueabihf.
>
> If I try the rust test manually, i.e.:
>
> /usr/local/bin/rustc --crate-type staticlib --target=armv7-unknown-linux-gnueabihf -o /tmp/conftest.rlib /tmp/conftest.rs
>
> ..it passes.
>
> Is there a way to force the rust target?

Not directly. But if configure is trying to use arm rather than armv7,
that suggests your C/C++ compiler is targetting something older than armv7 by
default. Can you try `--with-arch=armv7-a`?

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[John Frankish]

> > I'm trying to compile firefox natively on an RPi4 running tinycorelinux piCore.
> >
> > The configure phase fails because it tries to use arm-unknown-linux-gnueabihf
> > as the rust target instead of armv7-unknown-linux-gnueabihf.
> >
> > If I try the rust test manually, i.e.:
> >
> > /usr/local/bin/rustc --crate-type staticlib
> > --target=armv7-unknown-linux-gnueabihf -o /tmp/conftest.rlib
> > /tmp/conftest.rs
> >
> > ..it passes.
> >
> > Is there a way to force the rust target?
> >
> Not directly. But if configure is trying to use arm rather than armv7, that
> suggests your C/C++ compiler is targetting something older than armv7 by default.
> Can you try `--with-arch=armv7-a`?
>

It targets armv7l by default, but "--with-arch=armv7-a" fixed things - thanks.

After adjusting the location of nss headers and commenting out some simd code, firefox builds and runs :)