[LLVMdev] Any objections to turning on -Wunused-parameter? (and any other -Wunused-* that are off?)

Philip Reames listmail at philipreames.com
Mon Jul 20 16:18:53 PDT 2015


I'd be very happy to see this turned on as a warning; I'd be very 
reluctant to see it turned on as a error.  During a lot of code 
cleanups, the intermediate state of "deleted, but dead args still passed 
in" is a very useful intermediate step.  It greatly simplifies review to 
be able to separate the meat of the semantic change from the "just 
deleting a bunch of dead args" patch.  I'd be very very reluctant to 
create a situation where the patch with the semantic change but without 
the argument cleanup won't pass all the build bots.

Philip

(1 inline comment below as well)

On 07/18/2015 02:48 AM, Chandler Carruth wrote:
> LLVM and Clang both have lots of objects that are passed through many 
> different API boundaries. Things like AliasAnalysis in LLVM or Sema in 
> Clang get threaded all over the place.
>
> Over times, refactoring can often cause the parameters (or local 
> variables, or member variables, etc) to become dead. If we notice 
> this, we can often un-thread the interface through our APIs, sometimes 
> even reducing coupling, etc.
>
> But currently -Wunused-parameter is hard disabled. I've not checked to 
> see if there are any other disabling of -Wunused-* variants, but I'd 
> like to move the project toward firmly enabling them and being clean 
> with them.
>
> The technique I'd like to use is leaving out names of unused 
> parameters, using a /*CommentedName*/ if there is a useful name, 
> otherwise just omitting the name.
Sorry, could you rephrase?  Not sure what you're getting at here.
>
> All of this will require a reasonable amount of cleanup across the 
> projects which I'm happy to do prior to flipping defaults around. 
> Thoughts? Any concerns or objections?
>
> (I'll ask the same question and ofter to either enact the cleanups or 
> toggle the warning(s) back off for each of the less intertwined 
> subprojects like LLD, LLDB, Polly, etc.)
>
> -Chandler
>
>
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