RFR: 8291457: Clean up lifecycle of CDS dump-time data structures

[Calvin Cheung]

On Wed, 3 Aug 2022 07:15:49 GMT, Ioi Lam <iklam at openjdk.org> wrote:

> I've rewritten the following data CDS structures to follow the [C++ rule-of-three](https://en.cppreference.com/w/cpp/language/rule_of_three) to improve their lifecycle handling and fix a memory leak. This is done to prepare for future CDS changes that make more allocations during archive creation.
> 
>> Rule of Three: If a class requires a user-defined destructor, a user-defined copy constructor, or a user-defined copy assignment operator, it almost certainly requires all three.
> 
> - DumpTimeClassInfo
> - DumpTimeClassInfo::DTLoaderConstraint
> - DumpTimeClassInfo::DTVerifierConstraint
> - DumpTimeLambdaProxyClassInfo
> 
> I implemented some of the assignment operators using the [copy-and-swap idiom](https://en.cppreference.com/w/cpp/language/copy_assignment) to handle `Symbol` refcounting. Thanks to @kimbarrett for the suggestion.

src/hotspot/share/cds/dumpTimeClassInfo.hpp line 69:

> 67:       maybe_increment_refcount(_name);
> 68:     }
> 69:     DTLoaderConstraint& operator=(DTLoaderConstraint src) {

Could the src be passed as reference?

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PR: https://git.openjdk.org/jdk/pull/9722