On Wed, 11 Jan 2023 19:10:04 GMT, Archie L. Cobbs <d...@openjdk.org> wrote:
>> Good idea. Looks like the difference is in the noise, at least on my Macbook:
>>
>> Builds of master (jdk-21+3-69-gc6588d5bb3f)
>> ==================================
>>
>> Build times:
>>
>> real 2m24.650s
>> user 13m46.727s
>> sys 2m33.554s
>>
>> real 2m27.224s
>> user 13m43.464s
>> sys 2m37.251s
>>
>> real 2m26.658s
>> user 13m42.578s
>> sys 2m36.133s
>>
>> Builds of ThisEscape (jdk-21+3-125-g6e96a7d76f8)
>> ==================================
>>
>> Modifications:
>>
>> - Reverted files in the make/ subdirectory to enable warning
>> - Commented out lines 363-382 in ThisEscapeAnalyzer.java
>> so no warnings are actually reported
>>
>> Build times:
>>
>> real 2m25.912s
>> user 13m45.860s
>> sys 2m32.741s
>>
>> real 2m27.213s
>> user 13m44.830s
>> sys 2m36.596s
>>
>> real 2m25.756s
>> user 13m42.889s
>> sys 2m35.659s
>
> Regarding the assignment graph approach, I think that would work if the
> references are bouncing around strictly between variables, but what if the
> chain includes any of the more complicated stuff that is currently being
> tracked, such as various Java expressions, method invocations, conditionals,
> etc.?
>
> Consider this example:
>
> public class ThisEscapeLoop {
>
> public ThisEscapeLoop() {
> ThisEscapeLoop ref1 = this;
> ThisEscapeLoop ref2 = null;
> ThisEscapeLoop ref3 = null;
> ThisEscapeLoop ref4 = null;
> for (int i = 0; i < 100; i++) {
> ref4 = this.returnMe(ref3);
> ref3 = ref2;
> ref2 = ref1;
> if (ref4 != null)
> ref4.mightLeak();
> }
> }
>
> public <T> T returnMe(T x) {
> return x;
> }
>
> public void mightLeak() {
> }
> }
>
> If you are only looking at variable assignments with values that are other
> variables, then the chain "breaks" when `ref4` is assigned indirectly via
> `returnMe()`, and you miss the leak.
> Good idea. Looks like the difference is in the noise, at least on my Macbook:
>
> ```
> Builds of master (jdk-21+3-69-gc6588d5bb3f)
> ==================================
>
> Build times:
>
> real 2m24.650s
> user 13m46.727s
> sys 2m33.554s
>
> real 2m27.224s
> user 13m43.464s
> sys 2m37.251s
>
> real 2m26.658s
> user 13m42.578s
> sys 2m36.133s
>
> Builds of ThisEscape (jdk-21+3-125-g6e96a7d76f8)
> ==================================
>
> Modifications:
>
> - Reverted files in the make/ subdirectory to enable warning
> - Commented out lines 363-382 in ThisEscapeAnalyzer.java
> so no warnings are actually reported
>
> Build times:
>
> real 2m25.912s
> user 13m45.860s
> sys 2m32.741s
>
> real 2m27.213s
> user 13m44.830s
> sys 2m36.596s
>
> real 2m25.756s
> user 13m42.889s
> sys 2m35.659s
> ```
Thanks for trying it out - good to know that build time isn't affected.
-------------
PR: https://git.openjdk.org/jdk/pull/11874
