[foreign] RFR 8220544: Jextract; library dependent header filtering

[Jorn Vernee]

Discovered a bug in this after posting :(

DependencyFinder also needs to look for pointee and array element type 
cursors (which it currently doesn't). I've tested a working fix, but 
will also add some tests for the particular cases. Updated webrev coming 
soon™

Jorn

Jorn Vernee schreef op 2019-03-13 17:21:
> Hi,
> 
> After some discussion:
> https://mail.openjdk.java.net/pipermail/panama-dev/2019-March/004828.html
> 
> I've implemented the discussed approach to header & declaration 
> filtering.
> 
> Bug: https://bugs.openjdk.java.net/browse/JDK-8220544
> Webrev: 
> http://cr.openjdk.java.net/~jvernee/panama/webrevs/8220544/webrev.00/
> 
> There are a few new implementation classes:
>   * PattertnFilter; a helper class that encapsulates the Pattern based
> filtering code previously found in SymbolFilter. This code had to be
> reused.
>   * Filters; a Context sub-component holding PatternFilters for
> different types of declarations.
>   * DependencyFinder; finds dependencies of the root set of
> declarations found in the root headers.
>   * ElementFilter; filters out non-library symbol elements based on
> whether they appear in a root header or are required by something
> therein.
>   * RootSet; a helper class for managing root headers + required 
> element Trees.
> 
> I also encountered some crashes when debug printing Trees, which I've
> fixed/worked around accordingly.
> 
> FWIW, I tried this out with the Windows registry API and it's working
> very nicely! Going from well over 100 headers to under 10. Some room
> for improvement still exists; some empty headers and static forwarders
> could still be omitted, but imho that should be handled by a separate
> patch.
> 
> Thanks,
> Jorn