[llvm] r272880 - [llvm-objdump] Support detection of feature bits from the object and implement this for Mips.

[Daniel Sanders via llvm-commits]

There's two tests blocking it at the moment:
    LLVM :: CodeGen/ARM/trap.ll
    LLVM :: tools/llvm-objdump/ARM/macho-mattr-arm.test

trap.ll can use '-mtriple armv7-none-nacl' as the triple instead of '-mtriple armv7 -mattr +nacl-trap'.

macho-mattr-arm.test needs ARM to implement enough autodetection to detect set the fp-armv8 feature appropriately. I don't know ARM or MachO but I don't mind putting a quick patch together if someone tells me how to detect fp-armv8 from the MachO object.

There's also a few tests that use the option but don't fail when it has no effect:
    LLVM :: CodeGen/ARM/trap.ll
    LLVM :: MC/AArch64/optional-hash.s
    LLVM :: MC/Hexagon/v60-misc.s
    LLVM :: Object/Mips/feature.test
    LLVM :: Object/Mips/objdump-micro-mips.test
    LLVM :: tools/llvm-objdump/ARM/macho-mattr-arm.test
I can update these easily.

> -----Original Message-----
> From: Rafael Espíndola [mailto:rafael.espindola at gmail.com]
> Sent: 16 June 2016 13:10
> To: Daniel Sanders
> Cc: llvm-commits
> Subject: Re: [llvm] r272880 - [llvm-objdump] Support detection of feature
> bits from the object and implement this for Mips.
> 
> >    // Package up features to be passed to target/subtarget
> > -  std::string FeaturesStr;
> > +  SubtargetFeatures Features = Obj->getFeatures();
> >    if (MAttrs.size()) {
> > -    SubtargetFeatures Features;
> >      for (unsigned i = 0; i != MAttrs.size(); ++i)
> >        Features.AddFeature(MAttrs[i]);
> > -    FeaturesStr = Features.getString();
> >    }
> 
> Can we delete the MAttrs option in llvm-objdump now?
> 
> Cheers,
> Rafael