RFR: 8215380: Backout accidental change to String::length

[Joseph D. Darcy]

+1 to revert to the prior version,

Cheers,

-Joe

On 12/13/2018 3:20 PM, Claes Redestad wrote:
> Hi,
>
> I need to revert an accidental change to String.length
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8215380
> Patch inlined below
>
> Running the accidentally pushed version in naive microbenchmarks showed
> that avoiding the shift operation can improve throughput of str.length()
> by a small measure (~1.06x) for latin1-only inputs, neutral for mixed
> or utf16-only inputs, but also adds a branch (visible in profiling)
> which could blow up in more real cases. Regardless, it should be
> reviewed and discussed on it's own merits. Sorry!
>
> /Claes
>
> diff -r 8bf9268df0e2 src/java.base/share/classes/java/lang/String.java
> --- a/src/java.base/share/classes/java/lang/String.java    Thu Dec 13 
> 15:31:05 2018 +0100
> +++ b/src/java.base/share/classes/java/lang/String.java    Thu Dec 13 
> 23:59:43 2018 +0100
> @@ -664,7 +664,7 @@
>       *          object.
>       */
>      public int length() {
> -        return isLatin1() ? value.length : value.length >> UTF16;
> +        return value.length >> coder();
>      }
>
>      /**