RFR: 8275201: C2: hide klass() accessor from TypeOopPtr and typeKlassPtr subclasses [v2]

[Roland Westrelin]

On Mon, 16 May 2022 22:47:41 GMT, Xin Liu <xliu at openjdk.org> wrote:

>>> Looks very good!
>> 
>> Thanks for the review.
>
> hi, @rwestrel , 
> I see this patch uses covariant return in a few places, eg. 
> 
> -  virtual const Type *cast_to_exactness(bool klass_is_exact) const;
> +  virtual const TypeInstPtr* cast_to_exactness(bool klass_is_exact) const;
> 
> 
> and    
> 
> 
> // Speculative type helper methods.
> -  virtual const Type* remove_speculative() const;
> +  virtual const TypeOopPtr* remove_speculative() const;
> 
> 
> This contradicts "Avoid covariant return types." from [hotspot-style](https://github.com/openjdk/jdk/blob/master/doc/hotspot-style.md).  Is there any particular reason to change like that?  I see that compile.cpp leverages that to improve expressiveness.

Hi @navyxliu, 

> This contradicts "Avoid covariant return types." from [hotspot-style](https://github.com/openjdk/jdk/blob/master/doc/hotspot-style.md). Is there any particular reason to change like that? I see that compile.cpp leverages that to improve expressiveness.

I missed that. I will work on a subsequent change to remove the covariant return types.

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PR: https://git.openjdk.java.net/jdk/pull/6717