RFR (S): 8146820: JVMCI properties should use HotSpotJVMCIRuntime.getBooleanProperty mechanism

[Christian Thalinger]

> On Jan 12, 2016, at 12:03 PM, Doug Simon <doug.simon at oracle.com> wrote:
> 
>> 
>> On 12 Jan 2016, at 22:39, Christian Thalinger <christian.thalinger at oracle.com> wrote:
>> 
>>> 
>>> On Jan 12, 2016, at 10:14 AM, Doug Simon <doug.simon at oracle.com> wrote:
>>> 
>>> If we’re going with an enum, you could put accessors directly in the enum:
>>> 
>>>  private static final boolean TrustFinalDefaultFields = Option.TrustFinalDefaultFields.getBoolean(true);
>>> 
>>>  private static final String TraceMethodDataFilter = Option.TraceMethodDataFilter.getString(null);
>>> 
>>> You could then type the value of the options and check the right accessor is used:
>>> 
>>>   public enum Option {
>>>       ImplicitStableValues(boolean.class),
>>>       InitTimer,  // Note: Not used because of visibility issues (see InitTimer.ENABLED).
>>>       PrintConfig(boolean.class),
>>>       PrintFlags(boolean.class),
>>>       ShowFlags(boolean.class),
>>>       TraceMethodDataFilter(String.class),
>>>       TrustFinalDefaultFields(String.class);
>>> 
>>> Even ignoring these suggestions, the discipline imposed by the enum if a good idea.
>> 
>> Excellent idea!  I was also thinking about adding the default value to the enum.
> 
> Can you do that without having to box the default value?

No, we have to box but we can initialize all flags in the constructor:

http://cr.openjdk.java.net/~twisti/8146820/webrev.02/

We will not have many flags so this should be alright.  A PrintFlags looks like this:

$ ./build/macosx-x86_64-normal-server-release/jdk/bin/java -XX:+UnlockExperimentalVMOptions -XX:+EnableJVMCI -Djvmci.PrintFlags=true InitGraal
[List of JVMCI options]
  boolean ImplicitStableValues                     := true          
  boolean InitTimer                                := false         
  boolean PrintConfig                              := false         
  boolean PrintFlags                                = true          
  boolean ShowFlags                                := false         
   String TraceMethodDataFilter                    := null          
   String TrustFinalDefaultFields                  := true          

I’m almost tempted to move InitTimer to another package, like jdk.vm.ci.common …

> 
> -Doug