RFR: 8309751: Duplicate constant pool entries added during default method processing

[David Holmes]

On Fri, 29 Mar 2024 13:34:01 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

> This uses Ashutosh's patch to avoid adding duplicate constant pool entries during default method processing, with one change to make it conditional if not needed. I tested this locally and started writing a test, but writing a test is more difficult because duplicate constant pool entries don't actually violate the spec.
> 
> Tested with tier1-4 and ran some startup performance benchmarks on the patch.

src/hotspot/share/classfile/bytecodeAssembler.hpp line 98:

> 96:   static BytecodeCPEntry string(Symbol* symbol) {
> 97:     BytecodeCPEntry bcpe(STRING);
> 98:     bcpe._u.utf8 = symbol;

It seems to me that these changes have killed off the use of the `_u.string` union component.

I also can't make a connection between these changes and the duplicate removals.

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PR Review Comment: https://git.openjdk.org/jdk/pull/18548#discussion_r1547026990