RFR(XL) 8198698: Support Lambda proxy classes in dynamic CDS archive

Ioi Lam ioi.lam at oracle.com
Mon Jun 1 18:17:23 UTC 2020

Hi Calvin,

Some initial feedback:


JVM_ENTRY(void, JVM_RegisterLambdaProxyClassForArchiving(...,
                                               jstring invokedName,
                                               jobject invokedType...))

   Symbol* invoked_name = NULL;
   if (invokedName != NULL) {
     invoked_name = 
   Handle invoked_type_oop(THREAD, 
   Symbol* invoked_type = 
java_lang_invoke_MethodType::as_signature(invoked_type_oop(), false);

   SystemDictionaryShared::add_lambda_proxy_class(caller_ik, lambda_ik, 
invoked_name, invoked_type,
                                                  method_type, m, 

Theoretically, it's possible for java_lang_String::as_symbol_or_null and 
java_lang_invoke_MethodType::as_signature, etc, to return a NULL if the 
symbol is not present in the SymbolTable. I am not sure if in practice 
this may be true, but it seems safer to create the symbols if they don't 
exist yet, because you are going to record them anyway. So I would 
suggest using java_lang_String::as_symbol(), and passing 
intern_if_not_found==true to the as_signature() methods. This will have 
the side effect of adding 1 to the Symbol's reference count, which is 
needed because you are recording them in add_lambda_proxy_class().

Also, in JVM_LookupLambdaProxyClassFromArchive, I think your existing 
code in SystemDictionaryShared::get_shared_lambda_proxy_class should be 
able to handle NULL values, but it would be safer to add

    if (invoked_name == NULL || .... || instantiated_method_type == NULL) {
      return NULL;


Could you explain why this is necessary?

pkg_entry, CHECK);

(... more to come ...)

- Ioi

On 5/29/20 2:29 PM, Calvin Cheung wrote:
> RFE: https://bugs.openjdk.java.net/browse/JDK-8198698
> webrev: http://cr.openjdk.java.net/~ccheung/jdk15/8198698/webrev.00/
> There's a high level design doc in the attachment[1] of the RFE.
> Passed tiers 1 - 4 tests (including the new tests).
> thanks,
> Calvin
> [1] 
> https://bugs.openjdk.java.net/secure/attachment/88446/archive_lambda_proxy.txt

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