RFR(M) 8212605: Pure-Java implementation of AccessController.doPrivileged

[dean.long at oracle.com]

I think it's a good idea, but I believe it would require a CSR request.  
Do you mind if I file a separate issue for 
jdk.internal.vm.annotation.Hidden?

dl

On 10/31/18 6:11 PM, Vladimir Ivanov wrote:
> Dean,
>
> src/java.base/share/classes/java/security/AccessController.java:
> +    /**
> +     * Internal marker for hidden implementation frames.
> +     */
> +    /*non-public*/
> +    @Target(ElementType.METHOD)
> +    @Retention(RetentionPolicy.RUNTIME)
> +    @interface Hidden {
> +    }
>
> You declare @Hidden, but then map it to _method_Hidden along with 
> @Hidden from java.lang.invoke.LambdaForm.
>
> What do you think about moving LambdaForm.Hidden to 
> jdk.internal.vm.annotation instead and share among all usages?
>
> Best regards,
> Vladimir Ivanov
>
> On 31/10/2018 15:23, dean.long at oracle.com wrote:
>> https://bugs.openjdk.java.net/browse/JDK-8212605
>> http://cr.openjdk.java.net/~dlong/8212605/webrev.1
>>
>> This change implements AccessController.doPrivileged in Java. This 
>> gives a performance improvement while also being useful to Project 
>> Loom by removing the Java --> native --> Java transition.  One reason 
>> doPrivileged has historically been in native is because of the need 
>> to guarantee the cleanup of the privileged context when doPrivileged 
>> returns.  To do that in Java, the information that 
>> AccessController.getContext needs is pushed onto the Java stack as 
>> arguments to a method that getContext will recognize during its stack 
>> walk.  This allows us to remove the native privileged stack while 
>> guaranteeing that the privileged context goes away when the method 
>> returns.
>>
>> Tested with tier1-tier3 hotspot and jdk tests and JCK 
>> api/java_security tests.  For the first few rounds of testing, I kept 
>> the old native privileged stack and compared the results of the old 
>> and new implementations for each getContext call, which did catch 
>> some early bugs.  The changes were also examined by internal security 
>> experts and run through additional internal security tests.
>>
>> The improvement on this [1] doPrivileged microbenchmark is 
>> approximate 50x.
>>
>> There is no attempt to optimize getContext() or security permission 
>> checks in this change, however, this is intended to be a first step 
>> towards other possible improvements, for example those proposed here 
>> [2].
>>
>> dl
>>
>> [1] 
>> http://hg.openjdk.java.net/code-tools/jmh-jdk-microbenchmarks/file/fc4783360f58/src/main/java/org/openjdk/bench/java/security/DoPrivileged.java 
>>
>> [2] 
>> http://mail.openjdk.java.net/pipermail/security-dev/2017-December/016627.html 
>>
>>