Open code review for 8061999 Enhance VM option parsing to allow options to be specified

[David Holmes]

On 24/06/2015 3:43 AM, Ron Durbin wrote:
> David,
>
> The '-XX:Flags' option was considered during the research phase
> of this project and was rejected because of its limitations. The
> '-XX:Flags' option only works for boolean flag options and it
> uses a different syntax for the options than the command line.
> For example, '-XX:+UseSerialGC' would be specified as '+UseSerialGC'
> in the '-XX:Flags' option file.

I'm a little surprised the Flags option wasn't extended to cover these 
additional requirements. But presumably it should now be deprecated as 
we (again presumably) don't want to have two mechanisms for doing this.

Cheers,
David

> Here's an example:
>
> $ cat foo
> +UseSerialGC
>
> java -XX:+PrintVMOptions -XX:Flags=foo -version
>
> VM option '+UseSerialGC'
> VM option '+PrintVMOptions'
> VM option 'Flags=foo'
> java version "1.9.0-ea"
> Java(TM) SE Runtime Environment (build 1.9.0-ea-b69)
> Java HotSpot(TM) 64-Bit Server VM (build 1.9.0-ea-b69, mixed mode)
>
> Ron
>> -----Original Message-----
>> From: David Holmes
>> Sent: Monday, June 22, 2015 11:12 PM
>> To: Ron Durbin; hotspot-runtime-dev at openjdk.java.net
>> Subject: Re: Open code review for 8061999 Enhance VM option parsing to allow options to be specified
>>
>> Hi Ron,
>>
>> On 22/06/2015 10:52 PM, Ron Durbin wrote:
>>> Webrev URL:
>>> http://cr.openjdk.java.net/~rdurbin/8061999_OCR0_JDK9_webrev
>>>
>>>
>>> RFE request:
>>> https://bugs.openjdk.java.net/browse/JDK-8061999
>>>
>>> This RFE allows a file to be specified that holds VM Options that
>>> would otherwise be specified on the command line or in an environment variable.
>>> Only one options file may be specified on the command line and no options file
>>> may be specified in either of the following environment variables
>>> "JAVA_TOOL_OPTIONS" or "_JAVA_OPTIONS".
>>
>> How is this different to the existing: -XX:Flags=flags-file ???
>>
>> David
>> -----
>>
>>> The options file feature supports all VM options currently supported on
>>> the command line, except the options file option. The option to specify an
>>> options file is "-XX:VMOptionsFile=<Filename>".
>>> The options file feature supports an options file up to 1024 bytes in size
>>> and up to 64 options.
>>>
>>> This feature has been tested on:
>>>     OS:
>>>       Solaris, MAC, Windows, Linux
>>>     Tests:
>>>       Manual unit tests
>>>       JPRT with -testset hotspot (including the SQE proposed test coverage for this feature.)
>>>
>>>