[Buildroot] [PATCH v9 4/8] rust: new package

[Eric Le Bihan]

Hi!

On 17-12-28 22:08:53, Thomas Petazzoni wrote:
> Hello,
>
> On Thu, 28 Dec 2017 16:51:42 +0100, Eric Le Bihan wrote:
> > This new package provides rustc, the compiler for the Rust programming
> > language, built from source.
> >
> > Currently, only the host variant is built.
> >
> > The Rust compiler uses LLVM as its backend: a copy of LLVM source code
> > is provided and CMake is used to build it. It is possible to use a
> > pre-built external copy. When LLVM/clang will be available in Buildroot,
> > it would be possible to benefit from this feature and thus decrease
> > build time.
> >
> > LLVM is configured to generate code for x86, ARM, PowerPC and MIPS
> > architectures.
> >
> > The Rust compiler uses Cargo as its build system and is written in Rust.
> > Therefore this package depends on cargo-bin and rust-bin.
> >
> > The internal build process is as follows:
> >
> >  1. rustc-stage0, provided by rust-bin, is used to build rustc-stage1.
> >  2. rust-stage1 builds the final Rust compiler (rust-stage2)
> >     and the standard library for the host architecture.
>
> You're sometimes using rustc-stageX, sometimes just rust-stageX. Is
> this intentional ?

No, just a typo. I'll rephrase using "stageX compiler".

> > diff --git a/package/rust/rust.mk b/package/rust/rust.mk
> > new file mode 100644
> > index 0000000000..8dbec99bc5
> > --- /dev/null
> > +++ b/package/rust/rust.mk
> > @@ -0,0 +1,82 @@
> > +################################################################################
> > +#
> > +# rust
> > +#
> > +################################################################################
> > +
> > +RUST_VERSION = 1.22.1
> > +RUST_SOURCE = rustc-$(RUST_VERSION)-src.tar.xz
> > +RUST_SITE = https://static.rust-lang.org/dist
> > +RUST_LICENSE = Apache-2.0 or MIT
> > +RUST_LICENSE_FILES = LICENSE-APACHE LICENSE-MIT
> > +
> > +HOST_RUST_PROVIDES = host-rustc
> > +
> > +HOST_RUST_DEPENDENCIES = \
> > +	toolchain \
>
> It is somewhat unusual to have a host package depend on the target
> toolchain. I'm not sure we have any other host package in the tree
> doing this. I do understand why you're doing this, I'm just a little
> bit concerned that this special situation may be forgotten in the
> future. But there isn't much other solution, so it's probably good as
> it is.
>
> > +	host-rust-bin \
> > +	host-cargo-bin \
> > +	host-python \
>
> So you absolutely need python2 ? The build system is not python3
> compliant ?

The README explicitly states "`python` 2.7 (but not 3.x)", though it may
not need much work to port to Python3. Should I try to patch this?

> > +	host-cmake
>
> Could you use $(BR2_CMAKE_HOST_DEPENDENCY) instead ? This way, it would
> only build host-cmake if CMake is not already present on the system.
> This would save a bit of build time.

OK.

> > +ifeq ($(BR2_PACKAGE_JEMALLOC),y)
> > +HOST_RUST_DEPENDENCIES += jemalloc
> > +HOST_RUST_JEMALLOC_ENABLED = true
> > +HOST_RUST_JEMALLOC_CONF = 'jemalloc = "$(STAGING_DIR)/usr/lib/libjemalloc_pic.a"'
> > +else
> > +HOST_RUST_JEMALLOC_ENABLED = false
> > +endif
> > +
> > +HOST_RUST_VERBOSITY = $(if $(VERBOSE),2,0)
> > +
> > +# Some vendored crates contain Cargo.toml.orig files. The associated
>
> vendored -> vendor ?

Of course!

> > +# .cargo-checksum.json file will contain a checksum for Cargo.toml.orig but
> > +# support/scripts/apply-patches.sh will delete them. This will cause the build
> > +# to fail, as Cargo will not be able to find the file and verify the checksum.
> > +# So, remove all Cargo.toml.orig entries from the affected .cargo-checksum.json
> > +# files
> > +define HOST_RUST_EXCLUDE_ORIG_FILES
> > +	for file in $$(find $(@D) -name '*.orig'); do \
> > +		crate=$$(dirname $${file}); \
> > +		fn=$${crate}/.cargo-checksum.json; \
> > +		sed -i -e 's/"Cargo.toml.orig":"[a-z0-9]\+",//g' $${fn}; \
> > +	done
> > +endef
> > +
> > +HOST_RUST_POST_EXTRACT_HOOKS += HOST_RUST_EXCLUDE_ORIG_FILES
> > +
> > +define HOST_RUST_CONFIGURE_CMDS
> > +	( \
> > +		echo '[build]'; \
> > +		echo 'target = ["$(RUST_TARGET_NAME)"]'; \
> > +		echo 'cargo = "$(HOST_CARGO_BIN_DIR)/cargo/bin/cargo"'; \
> > +		echo 'rustc = "$(HOST_RUST_BIN_DIR)/rustc/bin/rustc"'; \
> > +		echo 'python = "$(HOST_DIR)/bin/python2"'; \
> > +		echo 'submodules = false'; \
> > +		echo 'vendor = true'; \
> > +		echo 'compiler-docs = false'; \
> > +		echo 'docs = false'; \
> > +		echo 'verbose = $(HOST_RUST_VERBOSITY)'; \
> > +		echo '[install]'; \
> > +		echo 'prefix = "$(HOST_DIR)"'; \
> > +		echo '[rust]'; \
> > +		echo 'use-jemalloc = $(HOST_RUST_JEMALLOC_ENABLED)'; \
> > +		echo '[target.$(RUST_TARGET_NAME)]'; \
> > +		echo 'cc = "$(TARGET_CROSS)gcc"'; \
> > +		echo $(HOST_RUST_JEMALLOC_CONF); \
> > +	) > $(@D)/config.toml
> > +endef
> > +
> > +define HOST_RUST_BUILD_CMDS
> > +	(cd $(@D); $(HOST_MAKE_ENV) $(HOST_DIR)/bin/python2 x.py \
> > +		build $(HOST_RUST_BUILD_OPTS))
> > +endef
> > +
> > +define HOST_RUST_INSTALL_CMDS
> > +	(cd $(@D); $(HOST_MAKE_ENV) $(HOST_DIR)/bin/python2 x.py \
> > +		dist $(HOST_RUST_BUILD_OPTS))
> > +	(cd $(@D); $(HOST_MAKE_ENV) $(HOST_DIR)/bin/python2 x.py \
> > +		install $(HOST_RUST_BUILD_OPTS))
> > +endef
> > +
> > +$(eval $(host-generic-package))
> > diff --git a/package/rustc/Config.in.host b/package/rustc/Config.in.host
> > index e42187d477..3a03140bcd 100644
> > --- a/package/rustc/Config.in.host
> > +++ b/package/rustc/Config.in.host
> > @@ -26,6 +26,21 @@ choice
> >  	help
> >  	  Select a Rust compiler
> >
> > +config BR2_PACKAGE_HOST_RUST
> > +	bool "host rust"
> > +	depends on BR2_HOST_GCC_AT_LEAST_4_7 # required by LLVM
> > +	# triggers ICE on trunc_int_for_mode, at explow.c:56
> > +	depends on BR2_TOOLCHAIN_GCC_AT_LEAST_5 || !BR2_aarch64
> > +	select BR2_PACKAGE_HAS_HOST_RUSTC
> > +	help
> > +	  This package will build the compiler for the host as well as
> > +	  two flavors of the standard library: one for the host, another
> > +	  for the target. Both are installed in the host directory.
> > +
> > +comment "host-rust needs a toolchain w/ gcc >= 5"
> > +	depends on BR2_aarch64
> > +	depends on !BR2_TOOLCHAIN_GCC_AT_LEAST_5
>
> What about the gcc 4.7 dependency? It would also need a comment.

OK.

Regards,

--
ELB