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

[Vladimir Kozlov]

Christian,

Can you put _flags first to avoid padding between _addr and _value in 
32-bit VM?

It would be nice enumerate flag's type and use int instead of strings:

enum {
   bool_flag = 1,
   intx_flag = 2,

+ #define RUNTIME_PRODUCT_FLAG_STRUCT(     type, name, value, doc) { 
type##_flag, XSTR(name), &name,              VALUE(value), 
NOT_PRODUCT_ARG(doc) Flag::Flags(Flag::DEFAULT | Flag::KIND_PRODUCT) },

Thanks,
Vladimir

On 9/12/13 9:58 AM, Christian Thalinger wrote:
>
> On Sep 11, 2013, at 5:34 PM, David Holmes <david.holmes at oracle.com> wrote:
>
>> 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.
>
> Good point.  I made that change:
>
> http://cr.openjdk.java.net/~twisti/8024545/webrev/src/share/vm/runtime/globals.cpp.udiff.html
>
>>
>> I also wonder whether a ConstFlag sub/superclass would simplify this at all?
>
> Maybe it would but then we need more infrastructure to read the additional entries.  Might be a wash.  SA only knows about offsets in structs and the flags array is statically defined.
>
>>
>> That aside I'm curious why the minimal VM size change is only 22K when client is 32K?
>
> The 32-bit product build also contains the server compiler.
>
> -- Chris
>
>>
>> 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.
>>>
>