[jdk19] RFR: 8290417: CDS cannot archive lamda proxy with useImplMethodHandle [v2]

[Mandy Chung]

On Mon, 18 Jul 2022 04:14:03 GMT, Ioi Lam <iklam at openjdk.org> wrote:

>> Since the impact of this bug can be big, and the fix is simple and low risk (just avoids doing optimizations), I'd like to put this into JDK 19 before RDP2 (Jul 21).
>> 
>> CDS cannot handle Lambda proxy classes that are generated in the useImplMethodHandle mode. This could happen with classfiles generated by JDK 8 or JDK 11 that access protected methods in a base class from a different package. E.g.,
>> 
>> 
>> class pkg1.Base {
>>     protected void doit(String s) {
>>         System.out.println(s);
>>     }
>> }
>> class pkg2.Child  extends pkg1.Base {
>>     void test() {
>>         Optional<String> opt = Optional.of("foo");
>>         opt.ifPresent(this::doit);
>>     }
>> }
>> 
>> 
>> More details of useImplMethodHandle can be found here: https://github.com/openjdk/jdk/blob/522b65743ca10fcba0a27d25b8fa11319999e228/src/java.base/share/classes/java/lang/invoke/InnerClassLambdaMetafactory.java#L183-L191
>> 
>> More details about the condition that triggers the error can be found in the test file Child.jcod.
>
> Ioi Lam has updated the pull request incrementally with one additional commit since the last revision:
> 
>   fixed typo

Looks fine.    I agree that this fix is low risk to disable archiving the lambda proxy in the case when passing a live method handle for invocation.

test/hotspot/jtreg/runtime/cds/appcds/test-classes/pkg1/BaseWithProtectedMethod.java line 29:

> 27: public class BaseWithProtectedMethod {
> 28:     protected void protectedMethod(String s) {
> 29:         Thread.dumpStack();

is it intentional for the test to keep dumping the stack?

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Marked as reviewed by mchung (Reviewer).

PR: https://git.openjdk.org/jdk19/pull/146