[llvm] r250929 - Silence Visual C++ warning in function summary parsing code (NFC)

[Teresa Johnson via llvm-commits]

On Wed, Oct 21, 2015 at 3:01 PM, David Blaikie <dblaikie at gmail.com> wrote:
>
>
> On Wed, Oct 21, 2015 at 2:52 PM, Teresa Johnson <tejohnson at google.com>
> wrote:
>>
>> On Wed, Oct 21, 2015 at 12:49 PM, David Blaikie <dblaikie at gmail.com>
>> wrote:
>> >
>> >
>> > On Wed, Oct 21, 2015 at 12:33 PM, Aaron Ballman via llvm-commits
>> > <llvm-commits at lists.llvm.org> wrote:
>> >>
>> >> On Wed, Oct 21, 2015 at 3:25 PM, Teresa Johnson via llvm-commits
>> >> <llvm-commits at lists.llvm.org> wrote:
>> >> > Author: tejohnson
>> >> > Date: Wed Oct 21 14:25:14 2015
>> >> > New Revision: 250929
>> >> >
>> >> > URL: http://llvm.org/viewvc/llvm-project?rev=250929&view=rev
>> >> > Log:
>> >> > Silence Visual C++ warning in function summary parsing code (NFC)
>> >> >
>> >> > Modified:
>> >> >     llvm/trunk/lib/Bitcode/Reader/BitcodeReader.cpp
>> >> >
>> >> > Modified: llvm/trunk/lib/Bitcode/Reader/BitcodeReader.cpp
>> >> > URL:
>> >> >
>> >> > http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Bitcode/Reader/BitcodeReader.cpp?rev=250929&r1=250928&r2=250929&view=diff
>> >> >
>> >> >
>> >> > ==============================================================================
>> >> > --- llvm/trunk/lib/Bitcode/Reader/BitcodeReader.cpp (original)
>> >> > +++ llvm/trunk/lib/Bitcode/Reader/BitcodeReader.cpp Wed Oct 21
>> >> > 14:25:14
>> >> > 2015
>> >> > @@ -5538,6 +5538,7 @@ std::error_code FunctionIndexBitcodeRead
>> >> >    // importing is added so that it can be tested.
>> >> >    SmallVector<uint64_t, 64> Record;
>> >> >    switch (Stream.readRecord(Entry.ID, Record)) {
>> >> > +    case bitc::FS_CODE_COMBINED_ENTRY:
>> >> >      default:
>> >> >        return error("Invalid record");
>> >>
>> >> What warning is this silencing?
>>
>> BitcodeReader.cpp(5543): warning C4065: switch statement contains
>> 'default' but no 'case' labels.
>>
>> >> It seems like the correct approach is
>> >> to remove the switch entirely.
>> >
>> >
>> > +1 - this looks like it should just be:
>> >
>> > if (Stream.readRecord(...))
>> >   return error(...);
>>
>> I could do that too, it is currently a placeholder for a TODO when the
>> full ThinLTO pipeline is hooked up. The comment just above is:
>>
>>   // TODO: Read a record. This interface will be completed when ThinLTO
>>   // importing is added so that it can be tested.
>>
>> Eventually it will parse FS_CODE_COMBINED_ENTRY records. If there is a
>> strong preference to remove this as Aaron suggested, I can do that
>> though.
>
>
> *shrug* not too fussed (& my suggestion's wrong too, of course, I guess it
> should be "Stream.readRecord(Entry.ID, Record); return error("Invalid
> record");" - no if/condition/control flow/etc), but probably wouldn't hurt
> to just strip out the placeholder code for now and leave the FIXME to
> describe where this code is going.
>
> *looks at the code some more*
> So this function is called currently, but always fails? Is that
> tested/useful? (I'm sure it was all reviewed by people with far more context
> than me when it went in, so don't let me derail you or anything - I'm just a
> tad confused at first glance)

It is currently reached from an interface in lib/Object that is not
yet used, to support lazy parsing of function summary data. I have
some code out for review in D13515 that uses the greedy parsing
interface for tests via llvm-link, but I didn't flesh this one out
completely since I didn't add a call yet for the lazy parsing (I
expect there to be tradeoffs and I'm not yet sure which approach will
win overall). So that's why I sketched out most of the support in this
routine but I didn't fill in the record handling yet. I'd prefer to
leave most of this in since I expect to add calls to it as well. Let
me know if that seems reasonable though!

Thanks,
Teresa

>
>>
>>
>> Teresa
>>
>> >
>> >>
>> >>
>> >> ~Aaron
>> >>
>> >> >    }
>> >> >
>> >> >
>> >> > _______________________________________________
>> >> > llvm-commits mailing list
>> >> > llvm-commits at lists.llvm.org
>> >> > http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>> >> _______________________________________________
>> >> llvm-commits mailing list
>> >> llvm-commits at lists.llvm.org
>> >> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>> >
>> >
>>
>>
>>
>> --
>> Teresa Johnson | Software Engineer | tejohnson at google.com | 408-460-2413
>
>



-- 
Teresa Johnson | Software Engineer | tejohnson at google.com | 408-460-2413