[OE-core] [v3][PATCH 2/2] goarch.bbclass: use MACHINEOVERRIDES and simplify go_map_arm()

[richard.purdie at linuxfoundation.org]

On Mon, 2019-03-18 at 11:21 -0400, Mark Asselstine wrote:
> Per https://github.com/golang/go/wiki/GoArm we need to set GOARM when
> cross building for ARMv5, ARMv6 and ARMv7. The current approach of
> using TUNE_FEATURES can be error prone, as we can see today when
> attempting to build for Cortex-A7 which results in GOARM=''.
> 
> Since the value of MACHINEOVERRIDES already consolidates the values
> of
> TUNE_FEATURES into something more consistent we can use the overrides
> mechanism to set GOARM, leaving just a little bit of logic in
> go_map_arm() to trigger off the arch (basically target vs host)
> for the setting of GOARM.
> 
> Signed-off-by: Mark Asselstine <mark.asselstine at windriver.com>
> ---
> 
> V2
> * Cover all ARMv7 Cortex* variants
> 
> V3
> * Switch to using MACHINEOVERRIDES/overrides mechanism
> 
>  meta/classes/goarch.bbclass | 19 +++++++++++--------
>  1 file changed, 11 insertions(+), 8 deletions(-)
> 
> diff --git a/meta/classes/goarch.bbclass
> b/meta/classes/goarch.bbclass
> index 39fea5e..8fdb443 100644
> --- a/meta/classes/goarch.bbclass
> +++ b/meta/classes/goarch.bbclass
> @@ -3,18 +3,26 @@ BUILD_GOARCH = "${@go_map_arch(d.getVar('BUILD_ARCH
> '), d)}"
>  BUILD_GOTUPLE = "${BUILD_GOOS}_${BUILD_GOARCH}"
>  HOST_GOOS = "${@go_map_os(d.getVar('HOST_OS'), d)}"
>  HOST_GOARCH = "${@go_map_arch(d.getVar('HOST_ARCH'), d)}"
> -HOST_GOARM = "${@go_map_arm(d.getVar('HOST_ARCH'),
> d.getVar('TUNE_FEATURES'), d)}"
> +HOST_GOARM = "${@go_map_arm(d.getVar('HOST_ARCH'),
> d.getVar('BASE_GOARM'), d)}"
>  HOST_GO386 = "${@go_map_386(d.getVar('HOST_ARCH'),
> d.getVar('TUNE_FEATURES'), d)}"
>  HOST_GOMIPS = "${@go_map_mips(d.getVar('HOST_ARCH'),
> d.getVar('TUNE_FEATURES'), d)}"
>  HOST_GOTUPLE = "${HOST_GOOS}_${HOST_GOARCH}"
>  TARGET_GOOS = "${@go_map_os(d.getVar('TARGET_OS'), d)}"
>  TARGET_GOARCH = "${@go_map_arch(d.getVar('TARGET_ARCH'), d)}"
> -TARGET_GOARM = "${@go_map_arm(d.getVar('TARGET_ARCH'),
> d.getVar('TUNE_FEATURES'), d)}"
> +TARGET_GOARM = "${@go_map_arm(d.getVar('TARGET_ARCH'),
> d.getVar('BASE_GOARM'), d)}"
>  TARGET_GO386 = "${@go_map_386(d.getVar('TARGET_ARCH'),
> d.getVar('TUNE_FEATURES'), d)}"
>  TARGET_GOMIPS = "${@go_map_mips(d.getVar('TARGET_ARCH'),
> d.getVar('TUNE_FEATURES'), d)}"
>  TARGET_GOTUPLE = "${TARGET_GOOS}_${TARGET_GOARCH}"
>  GO_BUILD_BINDIR =
> "${@['bin/${HOST_GOTUPLE}','bin'][d.getVar('BUILD_GOTUPLE') ==
> d.getVar('HOST_GOTUPLE')]}"
>  
> +# Use the MACHINEOVERRIDES to map ARM CPU architecture passed to GO
> via GOARM.
> +# This is combined with *_ARCH to set HOST_GOARM and TARGET_GOARM.
> +BASE_GOARM = ''
> +BASE_GOARM_armv7ve = '7'
> +BASE_GOARM_armv7a = '7'
> +BASE_GOARM_armv6 = '6'
> +BASE_GOARM_armv5 = '5'
> +
>  # Go supports dynamic linking on a limited set of architectures.
>  # See the supportsDynlink function in
> go/src/cmd/compile/internal/gc/main.go
>  GO_DYNLINK = ""
> @@ -74,12 +82,7 @@ def go_map_arch(a, d):
>  def go_map_arm(a, f, d):
>      import re
>      if re.match('arm.*', a):
> -        if 'armv7' in f:
> -            return '7'
> -        elif 'armv6' in f:
> -            return '6'
> -        elif 'armv5' in f:
> -            return '5'
> +        return f
>      return ''

regexs are slow, this is probably more pythonic too:

def go_map_arm(a, f, d):
    if a.startswith("arm"):
        return d.getVar('BASE_GOARM')
    return ''

and ditch f as a parameter?

Cheers,

Richard