[OE-core] [PATCH 1/1] Use TUNE_CCARGS for target compilation

[Andre McCurdy]

Hi Peter,

On Thu, Jan 14, 2016 at 1:04 PM, Peter Seebach
<peter.seebach at windriver.com> wrote:
> The initial gcc configuration is using TARGET_CFLAGS, but this is
> probably not what is intended, because TARGET_CFLAGS doesn't include
> any architecture-specific flags.

I think the current behaviour is deliberate, in order to try to make
it possible to reuse gcc binaries across builds for machines with
different CPU tuning flags.

See the comments associated with this commit from 2014, which
effectively makes all ARM toolchains default to soft float (instead of
defaulting to fpu calling convention of the target machine).

  http://git.openembedded.org/openembedded-core/commit/?id=ce1f3fd20d81545d6d5dfc68f86f9fddf8ac9bbf

> For PPC64, it's possible to end up with gcc configured to pass -a64 to
> the assembler, but be itself getting invoked without -m64, which can result
> in alignment problems in generated code. Solution: Instead of setting
> CFLAGS_FOR_TARGET to TARGET_CFLAGS, set it to TARGET_CFLAGS + TUNE_CCARGS.

Could that PPC64 issue be solved in the same way that the default arch
is set in gcc-configure-common.inc for the various MIPS targets?

  EXTRA_OECONF_append_mips64 = " --with-abi=64 --with-arch-64=mips64
--with-tune-64=mips64"
  EXTRA_OECONF_append_mips64el = " --with-abi=64 --with-arch-64=mips64
--with-tune-64=mips64"
  EXTRA_OECONF_append_mips64n32 = " --with-abi=64
--with-arch-64=mips64 --with-tune-64=mips64"
  EXTRA_OECONF_append_mips64eln32 = " --with-abi=64
--with-arch-64=mips64 --with-tune-64=mips64"


> However, for crosssdk cases, we need to prevent that from having any
> effect; this can be done by emptying out the TUNE_*ARGS flags in the
> crosssdk bbclass, because there is no "target tune" in crosssdk cases.
>
> Signed-off-by: Peter Seebach <peter.seebach at windriver.com>
> ---
>  meta/classes/crosssdk.bbclass                      | 4 ++++
>  meta/recipes-devtools/gcc/gcc-configure-common.inc | 2 +-
>  meta/recipes-devtools/gcc/gcc-cross.inc            | 2 +-
>  3 files changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/meta/classes/crosssdk.bbclass b/meta/classes/crosssdk.bbclass
> index 7315c38..ccff3ce 100644
> --- a/meta/classes/crosssdk.bbclass
> +++ b/meta/classes/crosssdk.bbclass
> @@ -6,6 +6,10 @@ PACKAGE_ARCH = "${SDK_ARCH}"
>  python () {
>         # set TUNE_PKGARCH to SDK_ARCH
>         d.setVar('TUNE_PKGARCH', d.getVar('SDK_ARCH', True))
> +       # We're not running a 'target', so clear these...
> +       d.setVar('TUNE_CCARGS', '')
> +       d.setVar('TUNE_LDARGS', '')
> +       d.setVar('TUNE_ASARGS', '')
>  }
>
>  STAGING_DIR_TARGET = "${STAGING_DIR}/${SDK_ARCH}-${SDKPKGSUFFIX}${SDK_VENDOR}-${SDK_OS}"
> diff --git a/meta/recipes-devtools/gcc/gcc-configure-common.inc b/meta/recipes-devtools/gcc/gcc-configure-common.inc
> index 45b3f15..4b4d91d 100644
> --- a/meta/recipes-devtools/gcc/gcc-configure-common.inc
> +++ b/meta/recipes-devtools/gcc/gcc-configure-common.inc
> @@ -120,7 +120,7 @@ do_configure () {
>         export CPPFLAGS_FOR_BUILD="${BUILD_CPPFLAGS}"
>         export CXXFLAGS_FOR_BUILD="${BUILD_CXXFLAGS}"
>         export LDFLAGS_FOR_BUILD="${BUILD_LDFLAGS}"
> -       export CFLAGS_FOR_TARGET="${TARGET_CFLAGS}"
> +       export CFLAGS_FOR_TARGET="${TARGET_CFLAGS} ${TUNE_CCARGS}"
>         export CPPFLAGS_FOR_TARGET="${TARGET_CPPFLAGS}"
>         export CXXFLAGS_FOR_TARGET="${TARGET_CXXFLAGS}"
>         export LDFLAGS_FOR_TARGET="${TARGET_LDFLAGS}"
> diff --git a/meta/recipes-devtools/gcc/gcc-cross.inc b/meta/recipes-devtools/gcc/gcc-cross.inc
> index aa10633..b6020a4 100644
> --- a/meta/recipes-devtools/gcc/gcc-cross.inc
> +++ b/meta/recipes-devtools/gcc/gcc-cross.inc
> @@ -43,7 +43,7 @@ do_compile () {
>         export LD_FOR_TARGET="${TARGET_SYS}-ld"
>         export NM_FOR_TARGET="${TARGET_SYS}-nm"
>         export CC_FOR_TARGET="${CCACHE} ${TARGET_SYS}-gcc"
> -       export CFLAGS_FOR_TARGET="${TARGET_CFLAGS}"
> +       export CFLAGS_FOR_TARGET="${TARGET_CFLAGS} ${TUNE_CCARGS}"
>         export CPPFLAGS_FOR_TARGET="${TARGET_CPPFLAGS}"
>         export CXXFLAGS_FOR_TARGET="${TARGET_CXXFLAGS}"
>         export LDFLAGS_FOR_TARGET="${TARGET_LDFLAGS}"
> --
> 2.3.1
>
> --
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