[llvm] r199886 - Prevent repetitive warnings for unrecognized processors and features

[Jim Grosbach]

On Jan 30, 2014, at 10:07 AM, Artyom Skrobov <Artyom.Skrobov at arm.com> wrote:

>> These are backend diagnostics only, right? I.e., they get issued by MC
>> when using developer tools like llvm-mc, llc, et. al.. They're
>> certainly not diagnostics we would ever expect to see from, e.g.,
>> clang or other user-level front-end. As such, I don't quite follow
>> why we should care about filtering duplicates at all. I don't oppose
>> uniquing them or anything, I just don't personally see it as a
>> priority. YMMV.
> 
> Yes, that's how it's supposed to be; but occasionally, these diagnostics
> "leak out" of the backend: one particular case that we're aware of, is
> 
> $ clang -target arm -mcpu=cortex-r4 -c test.c
> clang-3.5: warning: unknown platform, assuming -mfloat-abi=soft
> clang-3.5: warning: unknown platform, assuming -mfloat-abi=soft
> 'cortex-r4' is not a recognized processor for this target (ignoring
> processor)
> 'cortex-r4' is not a recognized processor for this target (ignoring
> processor)
> 'cortex-r4' is not a recognized processor for this target (ignoring
> processor)
> 'cortex-r4' is not a recognized processor for this target (ignoring
> processor)
> 'cortex-r4' is not a recognized processor for this target (ignoring
> processor)
> 'cortex-r4' is not a recognized processor for this target (ignoring
> processor)

Ew. That should be fixed in the front end to validate the argument to the -mcpu option. I agree that’s pretty bad as-is.