[patch] JamVM: Ignore all unknown options.

[Robert Lougher]

Hi Xerxes,

On 4 March 2011 15:07, Xerxes Ranby <xerxes at zafena.se> wrote:
>  Hi Robert
>
> I have attached a patch that alters JamVMs option parsing to ignore all
> unknown options and continue in order to make JamVM pass most of the OpenJDK
> jtreg tests.
>
> Without this approach i had to whitelist about 29 different options in order
> to run the OpenJDK jtreg testsuite. It was quite messy so we decided in the
> IcedTea project to simply ignore unknown options and then continue to be a
> better approach.
>

I'm not very keen on this change because it breaks compliance with the
JNI specification.  The specification explicitly states the behaviour
with unrecognised options:

http://download.oracle.com/javase/6/docs/technotes/guides/jni/spec/invocation.html#wp16334

typedef struct JavaVMInitArgs {
    jint version;
    jint nOptions;
    JavaVMOption *options;
    jboolean ignoreUnrecognized;
} JavaVMInitArgs;

...  If ignoreUnrecognized is JNI_FALSE, JNI_CreateJavaVM returns
JNI_ERR as soon as it encounters any unrecognized option strings. ...

With this change, JNI_CreateJavaVM will continue irrespective of
ignoreUnrecognized.


I understand what you want to do (stop it failing when passed
unrecognised options in the tests).  But changing handling of
ignoreUnrecognized is the wrong way (in my opinion).  A better option
is to change the java launcher to set ignoreUnrecognized to JNI_TRUE
instead of JNI_FALSE.

../openjdk/jdk/src/share/bin/java.c InitializeJVM():

...
    memset(&args, 0, sizeof(args));
    args.version  = JNI_VERSION_1_2;
    args.nOptions = numOptions;
    args.options  = options;
    args.ignoreUnrecognized = JNI_TRUE;
...

You probably want to do this only for JamVM and Cacao (e.g. when
-cacao or -jamvm is given, or one of them is the default).

Thanks,
Rob.

> Cheers
> Xerxes
>