toolchain/external: fix building the wrapper on MIPS

Some crazy folks use MIPS machines as build machines. ;-)

On MIPS, the only acceptable hash-style is 'sysv', because the MIPS ABI
defines that the GOT ordering to be the same as the symbols ordering,
while GNU hash requires symbols to be sorted by their hash.

Looking at binutils' code, it seems that only MIPS suffers from that
limitation.

Currently, we force the toolchain wrapper to be linked with both hash
styles, which breaks on MIPS.

So, fix that but singling out MIPS, and use sysv in that case, and both
otherwise.

Reported-by: Vicente Olivert Riera <Vincent.Riera@imgtec.com>
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

---
Absolutely untested on MIPS, as I do not have any MIPS machine powerfull
enough to do a build. Vicente will have to test it, since he is that
crazy one using MIPS build machines! ;-)
---
 toolchain/toolchain-external/toolchain-external.mk | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

Dear Yann E. MORIN,

On 11/26/2014 06:09 PM, Yann E. MORIN wrote:
> Some crazy folks use MIPS machines as build machines. ;-)
> 
> On MIPS, the only acceptable hash-style is 'sysv', because the MIPS ABI
> defines that the GOT ordering to be the same as the symbols ordering,
> while GNU hash requires symbols to be sorted by their hash.
> 
> Looking at binutils' code, it seems that only MIPS suffers from that
> limitation.
> 
> Currently, we force the toolchain wrapper to be linked with both hash
> styles, which breaks on MIPS.
> 
> So, fix that but singling out MIPS, and use sysv in that case, and both
> otherwise.
> 
> Reported-by: Vicente Olivert Riera <Vincent.Riera@imgtec.com>
> Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
> 
> ---
> Absolutely untested on MIPS, as I do not have any MIPS machine powerfull
> enough to do a build. Vicente will have to test it, since he is that
> crazy one using MIPS build machines! ;-)
> ---
>  toolchain/toolchain-external/toolchain-external.mk | 14 +++++++++++---
>  1 file changed, 11 insertions(+), 3 deletions(-)
> 
> diff --git a/toolchain/toolchain-external/toolchain-external.mk b/toolchain/toolchain-external/toolchain-external.mk
> index da3718c..51e0af5 100644
> --- a/toolchain/toolchain-external/toolchain-external.mk
> +++ b/toolchain/toolchain-external/toolchain-external.mk
> @@ -625,6 +625,15 @@ define TOOLCHAIN_EXTERNAL_INSTALL_BFIN_FLAT
>  endef
>  endif
>  
> +# We use --hash-style=both to increase the compatibility of
> +# the generated binary with older platforms, except for MIPS,
> +# where the only acceptable hash style is 'sysv'
> +ifeq ($(findstring mips,$(HOSTARCH)),mips)
> +TOOLCHAIN_EXTERNAL_WRAPPER_HASH_STYLE = sysv
> +else
> +TOOLCHAIN_EXTERNAL_WRAPPER_HASH_STYLE = both
> +endif
> +
>  # Build toolchain wrapper for preprocessor, C and C++ compiler and setup
>  # symlinks for everything else. Skip gdb symlink when we are building our
>  # own gdb to prevent two gdb's in output/host/usr/bin.
> @@ -647,9 +656,8 @@ define TOOLCHAIN_EXTERNAL_INSTALL_WRAPPER
>  			;; \
>  		esac; \
>  	done ;
> -	# We use --hash-style=both to increase the compatibility of
> -	# the generated binary with older platforms
> -	$(HOSTCC) $(HOST_CFLAGS) $(TOOLCHAIN_EXTERNAL_WRAPPER_ARGS) -s -Wl,--hash-style=both \
> +	$(HOSTCC) $(HOST_CFLAGS) $(TOOLCHAIN_EXTERNAL_WRAPPER_ARGS) \
> +		-s -Wl,--hash-style=$(TOOLCHAIN_EXTERNAL_WRAPPER_HASH_STYLE) \
>  		toolchain/toolchain-external/ext-toolchain-wrapper.c \
>  		-o $(HOST_DIR)/usr/bin/ext-toolchain-wrapper
>  endef
> 

I have tried your patch in a MIPS box and it works like a charm :-)

Reviewed-by: Vicente Olivert Riera <Vincent.Riera@imgtec.com>
Tested-by: Vicente Olivert Riera <Vincent.Riera@imgtec.com>

Cheers,

>>>>> "Yann" == Yann E MORIN <yann.morin.1998@free.fr> writes:

 > Some crazy folks use MIPS machines as build machines. ;-)
 > On MIPS, the only acceptable hash-style is 'sysv', because the MIPS ABI
 > defines that the GOT ordering to be the same as the symbols ordering,
 > while GNU hash requires symbols to be sorted by their hash.

 > Looking at binutils' code, it seems that only MIPS suffers from that
 > limitation.

 > Currently, we force the toolchain wrapper to be linked with both hash
 > styles, which breaks on MIPS.

 > So, fix that but singling out MIPS, and use sysv in that case, and both

s/but/by/

Committed, thanks.