RFR: 8066821(S) Enhance command line processing to manage deprecating and obsoleting -XX command line arguments

[Kim Barrett]

On Jul 17, 2015, at 1:30 PM, Derek White <derek.white at oracle.com> wrote:
> 
> Request for review:
> 
> [This updated webrev is being sent to wider audience, and has been merged with Gerard's option constraints check-in. Also factored out -XX:+AggressiveHeap processing into it's own chapter. I mean function :-)]
> 
> http://cr.openjdk.java.net/~drwhite/8066821/webrev.06/
> https://bugs.openjdk.java.net/browse/JDK-8066821

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src/share/vm/runtime/arguments.cpp
 284   JDK_Version obsoleted_in; // When the warning started (obsolete or deprecated).

"obsoleted_in" is confusingly named, given that it covers both the
"obsolete" and the "deprecated" states.  I think other reviewers
questioned whether "obsolete" was the proper term for that state.

At the risk of bikeshedding, I did a little exploring with a
thesaurus, and "discontinued" seems like a possibly better term for
that state.  The obsoleted_in field could retain that name, as
covering both deprecation and discontinuation.  Of course, that would
require some further updates, such as renaming is_newly_obsolete, and
updating various comments.

Some other possibilities include "defunct" and "disused", but I like
"discontinued" better than either of those.

------------------------------------------------------------------------------ 
src/share/vm/runtime/arguments.cpp
 288 // When a flag is eliminated, it can be added to this list in order to

I think "is eliminated" => "is made obsolete" or something like that.
I would expect "eliminated" == "removed", which is not what is being
described here.

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src/share/vm/runtime/arguments.cpp
 320 // When a flag is deprecated, it can be added to this list in order to issuing a warning when the flag is used.

"issuing" => "issue"

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src/share/vm/runtime/arguments.cpp
 808       return false; // "name" is a deprecated option that has expired.

I think the comment is wrong here.  I think it could just be a bogus
option name.  Later calls don't have any corresponding comment (which
is fine, just makes this one that I think might be wrong stand out
more).

------------------------------------------------------------------------------
src/share/vm/runtime/arguments.hpp
 420   // Returns true if the flag is obsolete and fits into the range specified
 421   // for being ignored.  In the case the 'version' buffer is filled in with 
 422   // the version number when the flag became obsolete. Otherwise the flag has 
 423   // expired and should be ignored.
 424   static bool is_newly_obsolete(const char* flag_name, JDK_Version* version);

The "otherwise" part of the description is not correct.  If this
returns false we don't actually know it has expired.  It could simply
not be present in the set of obsolete options.

Also, why the "newly" in the name?  "is_obsolete_flag" would be
consistent with "is_deprecated_flag".

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