[Buildroot] [PATCH 2/4] Add go host support

[Thomas Petazzoni <thomas.petazzoni@free-electrons.com>]

Geoff,

On Wed, 02 Mar 2016 19:23:33 +0000, Geoff Levand wrote:
> Add a new package 'go' which builds the host cross compiler and libraries for the
> go programming language.
> 
> Signed-off-by: Geoff Levand <geoff@infradead.org>

Like the previous commit, the title should be:

	go: new host package

> diff --git a/package/Config.in.host b/package/Config.in.host
> index 7cacef9..158fbca 100644
> --- a/package/Config.in.host
> +++ b/package/Config.in.host
> @@ -13,6 +13,7 @@ menu "Host utilities"
>  	source "package/genext2fs/Config.in.host"
>  	source "package/genimage/Config.in.host"
>  	source "package/genpart/Config.in.host"
> +	source "package/go/Config.in.host"
>  	source "package/go-bootstrap/Config.in.host"
>  	source "package/gptfdisk/Config.in.host"
>  	source "package/imx-usb-loader/Config.in.host"
> diff --git a/package/go/Config.in.host b/package/go/Config.in.host
> new file mode 100644
> index 0000000..928944b
> --- /dev/null
> +++ b/package/go/Config.in.host
> @@ -0,0 +1,14 @@
> +config BR2_PACKAGE_GO_ARCH_SUPPORTS
> +	bool
> +	default y
> +	depends on BR2_arm || BR2_aarch64 || BR2_i386 || BR2_x86_64 || BR2_powerpc
> +	depends on !BR2_ARM_CPU_ARMV4
> +
> +config BR2_PACKAGE_HOST_GO
> +	bool "host go"
> +	depends on BR2_PACKAGE_GO_ARCH_SUPPORTS
> +	select BR2_PACKAGE_HOST_GO_BOOTSTRAP

Due to the removal of Config.in.host for the go-bootstrap package, this
line has become useless.

> +	help
> +	  The Go Programming Language.
> +
> +	  https://golang.org

We normally don't have Config.in for host packages, as they are just
build dependencies. In this case, we could also decide to not have any
package/go/Config.in.host, and simply have the flannel package use
"host-go" in its <pkg>_DEPENDENCIES variable.

However, we may consider that some users may want to build the host Go
compiler even if they don't have a package that uses it, so maybe it's
acceptable.

I'm still a bit bothered by the fact that a Config.in option describing
a *host* package depends on BR2_PACKAGE_GO_ARCH_SUPPORTS. But I guess
it's fine since the Go compiler is really going to be a cross-compiler.

> diff --git a/package/go/go.mk b/package/go/go.mk
> new file mode 100644
> index 0000000..95168a7
> --- /dev/null
> +++ b/package/go/go.mk
> @@ -0,0 +1,73 @@
> +################################################################################
> +#
> +# golang
> +#
> +################################################################################
> +
> +GO_VERSION = 1.5.3
> +GO_SITE = https://storage.googleapis.com/golang
> +GO_SOURCE = go$(GO_VERSION).src.tar.gz
> +
> +GO_LICENSE = BSD-3c
> +GO_LICENSE_FILES = LICENSE
> +
> +GO_BOOTSTRAP = $(HOST_DIR)/usr/lib/go-1.4.2

Why don't you use $(GO_BOOTSTRAP_FINAL) instead ?

> +
> +ifeq ($(BR2_arm),y)
> +	GO_GOARCH = arm

Please don't indent such variable definitions.

> +else ifeq ($(BR2_aarch64),y)
> +	GO_GOARCH = arm64
> +else ifeq ($(BR2_i386),y)
> +	GO_GOARCH = 386
> +else ifeq ($(BR2_x86_64),y)
> +	GO_GOARCH = amd64
> +else ifeq ($(BR2_powerpc),y)
> +	GO_GOARCH = ppc64
> +else
> +	GO_GOARCH = unknown
> +endif
> +
> +ifeq ($(BR2_arm)$(BR2_ARM_CPU_HAS_VFPV3),yy)
> +	GO_GOARM = 7
> +else ifeq ($(BR2_arm)$(BR2_ARM_CPU_HAS_VFPV2),yy)
> +	GO_GOARM = 6
> +else ifeq ($(BR2_arm),y)
> +	GO_GOARM = 5
> +endif

You should use BR2_ARM_CPU_ARMV5, BR2_ARM_CPU_ARMV6 and
BR2_ARM_CPU_ARMV7 here.

> GO_HOST_DEPENDENCIES = host-go-bootstrap

Wrong variable name, it should be HOST_GO_DEPENDENCIES.

> GO_HOST_FINAL = $(HOST_DIR)/usr/lib/go

Ditto: HOST_GO_<...>

> GO_HOST_MAKE_ENV = \

Same.

> +define HOST_GO_INSTALL_CMDS
> +	$(INSTALL) -D -m 0755 $(@D)/bin/go $(GO_HOST_FINAL)/bin/go
> +	$(INSTALL) -D -m 0755 $(@D)/bin/gofmt $(GO_HOST_FINAL)/bin/gofmt
> +
> +	ln -sf ../lib/go/bin/go $(HOST_DIR)/usr/bin/
> +	ln -sf ../lib/go/bin/gofmt $(HOST_DIR)/usr/bin/
> +
> +	cp -a $(@D)/lib $(GO_HOST_FINAL)/
> +	cp -a $(@D)/src $(GO_HOST_FINAL)/

Same question: why do we install source code ?

> +
> +	mkdir -p $(GO_HOST_FINAL)/pkg
> +	cp -a $(@D)/pkg/include $(@D)/pkg/linux_* $(GO_HOST_FINAL)/pkg/
> +	cp -a $(@D)/pkg/tool $(GO_HOST_FINAL)/pkg/
> +	chmod -R +x $(GO_HOST_FINAL)/pkg/tool

Same question :-)

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com