RFR (L): 8024545: make develop and notproduct flag values available in product builds

[David Holmes]

Hi Chris,

There seems to be an awful lot "infrastructure" work needed to make 
something that sounds simple happen. :( All the changes to the scoping 
and the set/get methods tends to obscure the core change. My only 
suggestion here is that the "set" methods could perhaps factor this:

+   if (is_constant_in_binary()) {
+     fatal(err_msg("flag is constant: %s", _name));

into a check_writable() method so that it isn't duplicated so much.

I also wonder whether a ConstFlag sub/superclass would simplify this at all?

That aside I'm curious why the minimal VM size change is only 22K when 
client is 32K?

Thanks,
David

On 11/09/2013 10:56 AM, Christian Thalinger wrote:
> http://cr.openjdk.java.net/~twisti/8024545/webrev/
>
> 8024545: make develop and notproduct flag values available in product builds
> Reviewed-by:
>
> Right now the internal flag table only contains flags which are defined in a product build. This does not include develop and notproduct flags. Sometimes it is useful to have access to these values for post-mortem core file analysis or to read these values for compiler settings for a Java-based compiler.
>
> This change enables develop and notproduct flag values to be read by the serviceability agent. The binary size is increased by 42k for a 64-bit product build and by 32k for a 32-bit product build.
>
> Before:
>
> $ java -cp /java/re/jdk/8/latest/binaries/linux-x64/lib/sa-jdi.jar sun.jvm.hotspot.CLHSDB 9399
> Attaching to process 9399, please wait...
> hsdb> flags -nd
> InitialHeapSize = 495006528 5
> MaxHeapSize = 7920943104 5
> UseCompressedKlassPointers = true 5
> UseCompressedOops = true 5
> UseParallelGC = true 5
> hsdb> flags InlineMathNatives
> Couldn't find flag: InlineMathNatives
>
> After:
>
> $ java -cp $JAVA_HOME/lib/sa-jdi.jar sun.jvm.hotspot.CLHSDB 3726
> Attaching to process 3726, please wait...
> hsdb> flags -nd
> InitialHeapSize = 495006528 5
> MaxHeapSize = 7920943104 5
> UseCompressedKlassPointers = true 5
> UseCompressedOops = true 5
> UseParallelGC = true 5
> hsdb> flags InlineMathNatives
> InlineMathNatives = true 0
>
> This patch has one behavioral difference; when printing flags with e.g. PrintFlagsFinal in a debug build it prints "develop" for develop flags:
>
>      uintx AdaptiveSizePolicyGCTimeLimitThreshold    = 5               {develop}
>
> The output for product builds is unchanged.
>