Re: [Buildroot] [PATCH v3 05/11] package/pkg-cargo.mk: introduce the cargo package infrastructure

[Thomas Petazzoni <thomas.petazzoni@bootlin.com>]

Hello James,

On Thu, 6 Jan 2022 19:12:51 -0600
James Hilliard <james.hilliard1@gmail.com> wrote:

> > +$(2)_CARGO_ENV += \
> > +       CARGO_HOME=$$(HOST_DIR)/share/cargo \
> > +       __CARGO_TEST_CHANNEL_OVERRIDE_DO_NOT_USE_THIS="nightly" \
> > +       CARGO_TARGET_APPLIES_TO_HOST="false"  
> 
> Maybe want to set these additional options as well so that packages
> using cargo can
> build with only the env variables set(in some cases at least I think),

Thanks for the suggestion. However, could you be more specific than
"maybe" and "I think" ? The way you put it seems like we don't really
know why those variables would be useful and what they do.

> still probably
> need to pass some command line args but this should reduce the amount at least:
> RUSTC_TARGET_TRIPLE = $(subst -,_,$(call UPPERCASE,$(RUSTC_TARGET_NAME)))

Which command line arguments would be replaced by those variables?

> PKG_RUST_CARGO_ENV = \
>     CARGO_HOME=$(HOST_DIR)/share/cargo \

This one we already pass.

>     CARGO_BUILD_TARGET=$(RUSTC_TARGET_NAME) \

This one would replace the --target argument? Just to understand, what
would be the advantage of the variable compared to the comand line
argument?

>     CARGO_INSTALL_ROOT=$(TARGET_DIR)/usr \

This would replace --root $$(TARGET_DIR)/usr/ I suppose. Here as well,
any benefit/drawback of arguments vs. variables?

>     CARGO_TARGET_$(RUSTC_TARGET_TRIPLE)_LINKER=$(notdir $(TARGET_CROSS))gcc

How come things are working today with this one?

> 
> HOST_PKG_RUST_CARGO_ENV = \
>     CARGO_HOME=$(HOST_DIR)/share/cargo \

This one already passed.

>     CARGO_INSTALL_ROOT=$(HOST_DIR) \

This would replace --root $$(HOST_DIR) I suppose.

>     RUSTFLAGS="$(addprefix -C link-args=,$(HOST_LDFLAGS))"

This is already passed, although replicated between the build and
install steps of the host variant.

So essentially the only questions is:

 - Advantage of variables vs. command line options

 - Relevance of CARGO_TARGET_$(RUSTC_TARGET_TRIPLE)_LINKER=$(notdir $(TARGET_CROSS))gcc

Thanks!

Thomas
-- 
Thomas Petazzoni, co-owner and CEO, Bootlin
Embedded Linux and Kernel engineering and training
https://bootlin.com
_______________________________________________
buildroot mailing list
buildroot@buildroot.org
https://lists.buildroot.org/mailman/listinfo/buildroot