[m-rev.] for review: Commit java as Error should not fill in stack trace

[Zoltan Somogyi]

On Fri, 3 Nov 2017 14:49:15 +0000, Maxime Van Assche <mvanassche at odaseontologies.com> wrote:

> As far as I can tell, using Throwable for Commit does not require the stack trace.
> However, the default constructor of Error constructs the stack trace, which is costly.

I agree that we should not fill in the stack trace in exceptions used to implement commits.

> java/runtime/Commit.java :
> 	Override fillInStackTrace to do nothing
> 
> diff --git a/java/runtime/Commit.java b/java/runtime/Commit.java
> index a5f875ba..8cd0b68 100644
> --- a/java/runtime/Commit.java
> +++ b/java/runtime/Commit.java
> @@ -9,6 +9,10 @@
>  package jmercury.runtime;
> 
>  public class Commit extends java.lang.Error {
> +    public Throwable fillInStackTrace() {
> +        // do nothing, for performance reasons.
> +        return this;
> +    }
> 
>  }

I don't know our Java binding well enough to check this diff. Someone who
uses the Java backend should try to bootcheck it, and commit the diff
if that succeeds.

Zoltan.