RFR: 8276789: Support C++ lambda in ResourceHashtable::iterate [v4]

[Coleen Phillimore]

On Mon, 23 May 2022 17:13:36 GMT, Ioi Lam <iklam at openjdk.org> wrote:

>> I added two new template functions to reduce the boilerplate code when walking the entries in a ResourceHashtable
>> 
>> - `template<typename F> void ResourceHashtable::iterate(F f)`
>> - `template<typename F> void ResourceHashtable::iterate_all(F f)`
>> 
>> I also modified a couple of places in systemDictionaryShared.cpp to use the new functionality.
>> 
>> Testing with tiers 1-4.
>
> Ioi Lam has updated the pull request incrementally with one additional commit since the last revision:
> 
>   some clean up suggested by @stefank

I'm  a bit baffled by the layers of lambda expressions.

src/hotspot/share/cds/dumpTimeClassInfo.hpp line 209:

> 207:     } else {
> 208:       return _unregistered_count;
> 209:     }

This file has a blank first line, can you fix this?

src/hotspot/share/cds/dumpTimeClassInfo.inline.hpp line 76:

> 74:     return iter->do_entry(k, v);
> 75:   };
> 76:   iterate(function);

I don't understand this wrapper level.  Why doesn't this call into the resourceHashtable::iterate function directly?  Same with the iterate_all function?

src/hotspot/share/classfile/systemDictionaryShared.cpp line 665:

> 663:     ResourceMark rm;
> 664:     UnregisteredClassesDuplicationChecker dup_checker;
> 665:     _dumptime_table->iterate(&dup_checker);

Which iterate function does this call?

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PR: https://git.openjdk.java.net/jdk/pull/8761