On Fri, Jan 17, 2014 at 10:58 PM, Alan Modra <amo...@gmail.com> wrote:
> This patch cures PR59828 by translating all the -mcpu options at once,
> in order, to their equivalent assembler -m options by using a new spec
> function. In the process this removes some duplication.
>
> All the rhs of -mcpu= options from the command line can be extracted
> with %{mcpu=*:%*}, and then passed to a spec function. The new
> function was mostly already there in driver-rs6000.c to support
> -mcpu=native. However, the new spec function must be called for
> non-native configurations, so it's necessary to split driver-rs6000.c
> into two files, one for native support, the other always compiled in.
>
> I deliberately omitted converting over aix42.h, aix51.h and aix52.h
> because ASM_CPU_SPEC in those files translates -mcpu to different
> assembly options than the aix -mcpu=native support. Presumably the
> assembler on older versions of aix doesn't understand the newer
> options..
>
> Bootstrapped and regression tested powerpc64-linux natively, and
> x86_64-linux to powerpc64-linux cross. OK to apply?
>
> PR target/59828
> * config/rs6000/driver-rs6000.c (asm_names): Add entries for "native".
> (translate_cpu_to_asm): New function.
> Move everything else to..
> * config/rs6000/driver-nat-rs6000.c: ..here. New file.
> (host_detect_local_cpu): Make use of translate_cpu_to_asm.
> * config/rs6000/rs6000.h (ASM_CPU_SPEC): Likewise.
> (translate_cpu_to_asm): Declare.
> (EXTRA_SPEC_FUNCTIONS): Add translate_cpu_to_asm.
> * config/rs6000/x-rs6000: Adjust for renamed file.
> * config/rs6000/t-rs6000: Add driver-rs6000.o rule.
> * config/rs6000/aix53.h (ASM_CPU_SPEC): Use translate_cpu_to_asm.
> * config/rs6000/aix61.h (ASM_CPU_SPEC): Likewise.
> * config.gcc (extra_gcc_objs): Add driver-rs6000.o.
> * config.host (host_extra_gcc_objs): Remove driver-rs6000.o, add
> driver-nat-rs6000.o.
Alan,
ASM_CPU_SPEC is too fragile a mechanism. I would much prefer to
expand on the ".machine" directive that I added to
rs6000_file_start(). The initial implementation explicitly avoids
.machine when -mcpu= or --with-cpu= is present as a conservative
start.
It seems much better to select a .machine directive based on the
actual target ISA flag bits enabled than translating CPU command line
options to ASM options. Patches to replace ASM_CPU_SPEC with .machine
and expand functionality for AIX are welcome.
Thanks, David
