Re: [Patch ARM] Add support for a set of multilibs to be built for A profile cores.

[Richard Earnshaw <rearnsha at arm dot com>]

On 10/10/13 10:39, Ramana Radhakrishnan wrote:
> Hi,
> 
> 	One of our internal patches is a multilib patch that helps in testing 
> bare-metal toolchains for v7-a and above.
> 
> It's a bit brute force but this is something that we use internally 
> every night to build a set of base libraries in a hierarchical directory 
> structure to be used by bare metal toolchains along with those that want 
> to do so from a single toolchain. I don't claim to particularly like 
> this patch especially the part of writing the MULTILIB_REUSE macros to 
> match as many of the options that I could think of that folks would use 
> sensibly along with such a toolchain.
> 
> 
> - I've missed a few -mfpu options but I deemed them to be uncommon 
> enough. If people want to submit a follow on patch for those, I'd be 
> happy to take them but this will do for now.
> 
> - Additionally if people want to extend this to cover M profile cores 
> and all cores, feel free to do so. I don't intend to do so in this cut 
> of the makefile fragment.
> 
> - I have deliberately avoided documenting that ARM in the supported list 
> for --with-multilib-list, because we aren't providing this option like 
> other targets in this regard.
> 
> - Additionally one cannot use with --with-cpu , --with-fpu, --with-float 
> --with-mode --with-arch command line options with this as the make file 
> fragment is written assuming such a case.
> 
> This does not handle all the general options that --with-multilib-list 
> provides with actually providing options on the command line, trying to 
> write this with the command lines as suggested in other ports for the 
> length that I have in mind, is just going to be unweildy and extremely 
> irritating on the command line.
> 
> Additionally there is no easy way of supplying multilib_reuse options on 
> the command line, with the result that the configure command line would 
> be long, prone to error and extremely fragile. This is less fragile than 
> that approach and hence I prefer this form for the ARM backend for the 
> current work and for people who are interested in this sort of a thing.
> 
> Additionally tested with a noddy shell script that goes something like 
> and checked for no failures.
> 
> for mode in marm mthumb ; do
> for fabi in hard softfp  ; do
> for fpu in vfpv3-d16 vfpv3 vfpv4-d16 vfpv4 neon neon-vfpv4 fp-armv8 
> neon-fp-armv8  ; do
> for cpu in cortex-a8 cortex-a5 cortex-a9 cortex-a7 cortex-a15 
> cortex-a53; do
>    x=`$COMPILER /tmp/hello.c -mcpu="$cpu" -mfpu="$fpu" 
> -mfloat-abi="$fabi" "-$mode" -print-multi-directory -lm`
>    if [ "$x" != "." ];
>    then
>        echo "PASS: mcpu=$cpu mfpu=$fpu mfloat-abi=$fabi -$mode"
>    else
>        echo "FAIL: mcpu=$cpu mfpu=$fpu mfloat-abi=$fabi -$mode"
>    fi
> done
> done
> done
> 
> for fpu in vfpv3-d16 vfpv3 vfpv4-d16 vfpv4 neon neon-vfpv4 fp-armv8 
> neon-fp-armv8 crypto-neon-fp-armv8 ; do
> for fabi in hard softfp  ; do
> for arch in armv7-a armv8-a ; do
> #  $COMPILER /tmp/hello.c -march="$arch" -mfpu="$fpu" 
> -mfloat-abi="$fabi" -"$mode" -lm
>    x=`$COMPILER /tmp/hello.c -march="$arch" -mfpu="$fpu" 
> -mfloat-abi="$fabi" "-$mode" -print-multi-directory -lm`
>   if [ "$x" != "." ];
>   then
>        echo "PASS: march=$arch mfpu=$fpu mfloat-abi=$fabi -$mode"
>    else
>        echo "FAIL: march=$arch mfpu=$fpu mfloat-abi=$fabi -$mode"
>    fi
> done
> done
> done
> 
> 
> Tested on arm-none-eabi with --with-multilib-list=aprofile C, C++ and 
> Fortran with no regressions on an ARM fast model. Note that this is not 
> on by default so will not affect default build times and we have 
> auto-testers internally that use this feature.
> 
> I think I can apply the changes for config.gcc but I'd still like 
> another set of eyes on this please.
> 
> Ok ?
> 
> regards
> Ramana
> 
> 
> <DATE>  Matthew Gretton-Dann  <matthew.gretton-dann@arm.com>
> 	Ramana Radhakrishnan  <ramana.radhakrishnan@arm.com>
> 
> 
> * config/arm/t-aprofile: New file.
> * config.gcc: Handle --with-multilib-list option.
> 
> 

OK.

R.