[jdk17] RFR: JDK-8263321: Regression 8% in javadoc-steady in 17-b11 [v2]

[Jonathan Gibbons]

On Tue, 15 Jun 2021 16:00:02 GMT, Hannes Wallnöfer <hannesw at openjdk.org> wrote:

>> This change fixes a performance regression caused by passing instances of `com.sun.tools.javac.util.Name` to a `html.markup.Text` object, where their content is accessed using`CharSequence` methods which are implemented very inefficiently. 
>> 
>> Since improving `javac.util.Name` will likely require a bit more work (see JDK-8268622), a safe short term solution for JDK 17 is to make sure instances of `Name` are converted to `String` before invoking said `CharSequence` methods. The main fix is to convert to `String` early in `Entity.escapeHtmlChars(CharSequence)` which is invoked by the `Text` constructor. There are a few more `.toString()` invocations added in places where a `Name` is appended to a `StringBuilder`, although these have less performance impact.
>
> Hannes Wallnöfer has updated the pull request incrementally with one additional commit since the last revision:
> 
>   JDK-8268557: Update year in copyright header

This is OK as a short-term fix. I hope we can revert it when the underlying problem in `Name`is fixed.

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PR: https://git.openjdk.java.net/jdk17/pull/42