[Buildroot] [PATCH 8/9] package/go: Build special host binaries

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

Hello,

On Thu, 12 May 2016 00:08:48 +0000, Geoff Levand wrote:
> To work around cross compile limitations of go's build scripts, when the
> host and target arches are the same build the host go binaries with
> CC_FOR_TARGET set to the host compiler.

What happens when the host and target architectures are different? It
all works fine?

Is the problem just that Go doesn't "cross compile" properly when the
host and target architectures are the same ?

> +# To work around cross compile limitations of go's build scripts, when the

Please give more details about those "limitations".

> +# host and target arches are the same build the host go binaries with
> +# CC_FOR_TARGET set to the host compiler.
> +ifeq ($(ARCH),$(HOSTARCH))
> +	HOST_GO_BUILD_SPECIAL = y

Don't indent this line.

> +endif
> +
> +HOST_GO_ENV_COMMON = \
>  	GOROOT_BOOTSTRAP=$(HOST_GO_BOOTSTRAP_ROOT) \
>  	GOROOT_FINAL=$(HOST_GO_ROOT) \
> -	GOROOT="$(@D)" \
>  	GOBIN="$(@D)/bin" \
>  	GOARCH=$(GO_GOARCH) \
>  	$(if $(GO_GOARM),GOARM=$(GO_GOARM)) \
>  	GOOS=linux \
>  	CGO_ENABLED=1 \
> +	CC=$(HOSTCC_NOCCACHE)

This addition seems unrelated to the patch. And why are you using
HOSTCC_NOCCACHE and not just HOSTCC ?

> +
> +HOST_GO_MAKE_ENV = \
> +	$(HOST_GO_ENV_COMMON) \
> +	GOROOT="$(@D)" \
>  	CC_FOR_TARGET=$(TARGET_CC) \
>  	CXX_FOR_TARGET=$(TARGET_CXX)
>  
> +HOST_GO_MAKE_ENV_SPECIAL = \
> +	$(HOST_GO_ENV_COMMON) \
> +	GOROOT="$(@D).host" \
> +	CC_FOR_TARGET=$(HOSTCC_NOCCACHE) \
> +	CXX_FOR_TARGET=$(HOSTCC_NOCCACHE) \

Please no final backslash on the last line.

> +define HOST_GO_CONFIGURE_CMDS
> +	if [ "$(HOST_GO_BUILD_SPECIAL)" ]; then \
> +		cp -a $(@D) $(@D).host; \
> +	fi
> +endef

Please use make conditionals, i.e:

ifeq ($(HOST_GO_BUILD_SPECIAL),y)
define HOST_GO_CONFIGURE_CMDS
	cp -a $(@D) $(@D).host
endef
endif

> +
>  define HOST_GO_BUILD_CMDS
>  	cd $(@D)/src && $(HOST_GO_MAKE_ENV) ./make.bash

You really need a different set of environment variables for here?

> +	if [ "$(HOST_GO_BUILD_SPECIAL)" ]; then \
> +		rm -f $(@D)/bin/go $(@D)/bin/gofmt; \
> +		cd $(@D).host/src && $(HOST_GO_MAKE_ENV_SPECIAL) ./make.bash; \

And here ?

Also, same here: use make conditionals, i.e:

ifeq ($(HOST_GO_BUILD_SPECIAL),y)
define HOST_GO_BUILD_SPECIAL_CMDS
	...
endef
endif

define HOST_GO_BUILD_CMDS
	.... build go normally ...
	$(HOST_GO_BUILD_SPECIAL_CMDS)
endef

> +	fi
>  endef
>  
>  define HOST_GO_INSTALL_CMDS
> @@ -66,7 +93,8 @@ define HOST_GO_INSTALL_CMDS
>  	cp -a $(@D)/lib $(HOST_GO_ROOT)/
>  
>  	mkdir -p $(HOST_GO_ROOT)/pkg
> -	cp -a $(@D)/pkg/include $(@D)/pkg/linux_* $(HOST_GO_ROOT)/pkg/
> +	cp -a $(@D)/pkg/include $(HOST_GO_ROOT)/pkg/
> +	cp -a $(@D)/pkg/linux_* $(HOST_GO_ROOT)/pkg/

This change seems useless and unrelated.

Thanks!

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