RFR 8130459(M): Add additional validation after heap creation

[sangheon.kim]

Hi Coleen,

Thank you for reviewing this.

On 07/16/2015 01:05 PM, Coleen Phillimore wrote:
>
> http://cr.openjdk.java.net/~sangheki/8130459/webrev.00/src/share/vm/runtime/commandLineFlagConstraintList.cpp.udiff.html 
>
>
> This
>
> +CommandLineFlagConstraint::ConstraintType 
> CommandLineFlagConstraint::change_to_enum(const char* type) {
>
> function will return the enum if there is junk at the end of the 
> string.  Is that expected?
No.
Now I'm thinking like below:
if (strncmp(type, afterParse_str, 10) == 0 && type[10] == '\0') {
Or do you have any recommendation?
Let me send a revised webrev after hearing your opinion.

>
> http://cr.openjdk.java.net/~sangheki/8130459/webrev.00/src/share/vm/runtime/commandLineFlagConstraintList.hpp.udiff.html 
>
>
> Generally the nonstatic data members of a class are written before the 
> functions (at the top of the class declaration).  You may have to put 
> these after the enum declaration, but not at the bottom.
Okay, I will fix it.

>
> I like this change.  I think it looks good.
Thank you!

Sangheon

>
> Coleen
>
>
> On 7/15/15 3:33 AM, sangheon.kim wrote:
>> Hi all,
>>
>> Please review this change of adding additional validation on 
>> command-line flag checking framework.
>>
>> Recently we introduced Command-line flag checking framework 
>> (JDK-8059557 <https://bugs.openjdk.java.net/browse/JDK-8059557>, JEP 
>> 245: Validate JVM Command-Line Flag Arguments ) for ranges and 
>> constraints.
>> And most cases this works great.
>> Unfortunately there are some flags which can be checked after heap 
>> creation and these flags are hard to be checked under current framework.
>> In this regard, I suggest to have an additional constraint checking.
>>
>> This suggestion adds one more constraint checking stage after memory 
>> initialization.
>> And if we need more validations we can extend it.
>>
>> There are 2 big changes.
>>
>> 1. Flag declaration.
>> 'constraint(FUNC)' -> 'constraint(FUNC,TYPE)'
>> This webrev has 3 types, Anytime, AfterParse and AfterMemoryInit.
>> - Anytime: current constraint functions which don't use 
>> CommandLineFlags::finishedInitializing().
>> - AfterParse: constraint functions which use 
>> CommandLineFlags::finishedInitializing().
>> - AfterMemoryInit: I added only YoungPLABSize as an example.
>>   * All GC related flags will be covered by JDK-8078555 
>> <https://bugs.openjdk.java.net/browse/JDK-8078555>: GC: implement 
>> ranges (optionally constraints) for those flags that have them missing.
>>
>> 2. Previous constraint functions have to use 
>> 'CommandLineFlags::finishedInitializing()' if the flag needs to be 
>> checked after Argument::parse().
>> However, with this suggestion there's no need to call the function. 
>> Instead framework will decide when the constraint function is needed 
>> to be called.
>> And previously constraint functions are called twice while this 
>> change will call each constraint function only one time.
>>
>> CR: https://bugs.openjdk.java.net/browse/JDK-8130459
>> webrev: http://cr.openjdk.java.net/~sangheki/8130459/webrev.00/
>> Testing: JPRT, UTE(vm.quick-pcl) and tests at test/runtime/CommandLine.
>>
>> Thanks,
>> Sangheon
>