On Mon, 9 Sep 2024 17:20:44 GMT, Shaojin Wen <s...@openjdk.org> wrote:
>> The string concatenation of the java.base module is implemented using >> StringBuilder. By providing a series of concat methods in >> StringConcatHelper, it is used in the java.lang package to replace string >> concatenation. >> >> These concat methods can also be exposed through JLA for use by other >> packages, such as java.lang.constant. >> >> These concat methods can replace Concat1 and become part of >> StringConcatFactory#simpleConcat > > Shaojin Wen has updated the pull request incrementally with one additional > commit since the last revision: > > more 2 arguments simple concat src/java.base/share/classes/java/lang/invoke/StringConcatFactory.java line 529: > 527: mh = simpleConcat3(paramType0); > 528: mh = MethodHandles.insertArguments(mh, 0, prefix); > 529: return MethodHandles.filterArguments(mh, 1, > objectStringifier()); While this is a fun trick it seems like there's a non-trivial cost here? We'd go down different paths and generate different classes for `"foo" + bar + baz` and `"foo" + bar + " .. " + baz` with this. Special casing when we get the added shapes for more or less free (plain `simpleConcat()`) is a different matter but here you need to construct a new couple of shapes with `insert-` and `filterArguments`. (Check on paramType1 could be `!paramType1.isPrimitive()`) ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/20726#discussion_r1751694776
