------- Comment #4 from ddaney at avtrex dot com 2006-03-27 18:42 ------- Subject: Re: NullPointerException not generated for large classes...
mckinlay at redhat dot com wrote: > ------- Comment #3 from mckinlay at redhat dot com 2006-03-27 18:28 ------- > GCJ could be made to generate explicit null checks when large offsets are > used. > It is probably relatively rare to have a normal object that is larger than a > page, so performance for most apps shouldn't be effected. > > Note that array accesses should not need this as the "length" field will be > dereferenced first, triggering NullPointerException, assuming bounds checks > are > used. I would also expect Strings should not have a problem. > > Do we know who's heap exactly is mapped at such a low address? If its mapped > by > Java/Boehm GC, then we can probably just fix the GC to not map things at such > low addresses (or to insert guard pages there instead). It is libgcj's (Boehm GC) heap in my tests that is at 0x1000. This message: http://gcc.gnu.org/ml/java/2006-03/msg00206.html Has more thoughts on the subject. David Daney. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26858