Bytecode verifier

[Andrew Haley]

Ranjit Mathew writes:
 > Tom Tromey wrote:
 > > Andrew> I know that there is a somewhat decent verifier in libgcj, so
 > > Andrew> perhaps we could replace the gcj verifer with that one.
 > > 
 > > FWIW, I started work on putting the libgcj verifier into gcj last
 > > year.  I haven't had time to finish yet, and in the meantime I made
 > > some major changes to the libgcj verifier (fixing the subroutine
 > > bugs), so my changes won't apply cleanly any more.
 > > 
 > > Anyway, I had a mostly-working prototype.  I was able to get the
 > > verifier into gcc, bridge the type differences, and have it actually
 > > verify code.  gcc still crashed since I hadn't yet wrote the code to
 > > let the libgcj verifier tell gcc about type maps.  Parts of this were
 > > pretty ugly, so some polishing would also be required...
 > 
 > Can you please elaborate a bit more? I mean, wouldn't this
 > create licensing issues? The configury will also get
 > a little weird I guess.
 > 
 > It is a Good Thing, IMHO, but I'm just confused by
 > how you did it, especially after I remember us being
 > reticent to even use libiberty in libgcj and by the
 > order in which I see different parts of the GCC tree being
 > configured and built (libiberty, front-ends, libraries).

libiberty is GPL; libgcj is GPL+exception.  There's no reason to to
link GPL code with GPL+exception code.

Andrew.