ARM GCC machine options for RTEMS 6

[Chris Johns]

On 3/7/20 5:06 pm, Sebastian Huber wrote:
> Hello,
> 
> someone from ARM changed the machine options used to build the RTEMS multilibs
> some time ago (I think GCC 8):

Was a reason given?

> 
> arm-rtems6-gcc -print-multi-lib -march=armv4t
> .;
> thumb;@mthumb
> armv5te+fp/hard;@march=armv5te+fp at mfloat-abi=hard
> thumb/armv6-m;@mthumb at march=armv6-m
> thumb/armv7-a;@mthumb at march=armv7-a
> thumb/armv7-r;@mthumb at march=armv7-r
> thumb/cortex-m3;@mthumb at mcpu=cortex-m3
> thumb/cortex-m4+nofp;@mthumb at mcpu=cortex-m4+nofp
> thumb/armv7-a+simd/hard;@mthumb at march=armv7-a+simd at mfloat-abi=hard
> thumb/armv7-r+fp/hard;@mthumb at march=armv7-r+fp at mfloat-abi=hard
> thumb/cortex-m4/hard;@mthumb at mcpu=cortex-m4 at mfloat-abi=hard
> thumb/cortex-m7/hard;@mthumb at mcpu=cortex-m7 at mfloat-abi=hard
> eb/thumb/armv7-r;@mbig-endian at mthumb@march=armv7-r
> eb/thumb/armv7-r+fp/hard;@mbig-endian at mthumb@march=armv7-r+fp at mfloat-abi=hard
> 
> It seems that our current machine options still map to the right multilib:
> 
> arm-rtems6-gcc -print-multi-directory -march=armv7-a -mthumb -mfpu=neon
> -mfloat-abi=hard -mtune=cortex-a9
> thumb/armv7-a+simd/hard
> 
> arm-rtems6-gcc -print-multi-directory -mthumb -mcpu=cortex-m4 -mfpu=fpv4-sp-d16
> -mfloat-abi=hard
> thumb/cortex-m4/hard
> 
> arm-rtems6-gcc -print-multi-directory -march=armv7-r -mthumb -mbig-endian
> eb/thumb/armv7-r
> 
> arm-rtems6-gcc -print-multi-directory -march=armv7-r -mthumb -mbig-endian
> -mfpu=vfpv3-d16 -mfloat-abi=hard
> eb/thumb/armv7-r+fp/hard
> 
> Should we change the options to match the ones given in the multilib definition
> or should we keep the current options? If we change the options, then we can no
> longer build with GCC 7.

Would we need to build gcc 7 for RTEMS 6?

Chris