[fedora-java] line numbers

[Andrew Haley]

Bryce McKinlay writes:
 > Andrew Haley wrote:
 > > Anthony Green writes:
 > >  > Now that we have a new libgcj in FC-5, azureus logging seems to be
 > >  > working.  I've been comparing log files between Sun JRE and gcj runs,
 > >  > and have filed 1 GNU Classpath bug so far.
 > >  > 
 > >  > One thing that is annoying is that I'm not getting line numbers in the
 > >  > azureus debug output.  Azureus' calls to
 > >  > StackTraceElement.getLineNumber() always result in -1.  I have the
 > >  > azureus debug RPM installed, and just assumed that this would be enough
 > >  > to get line number info.  Maybe I'm misremembering all this.  Should
 > >  > StackTraceElement.getLineNumber() return good info for bc-compiled code?
 > >
 > > Yes, it should.  However, StackTraceElement.getLineNumber() doesn't
 > > work with separate debuginfo.
 > >   
 > We could also solve this by having the Java RPMs strip the rest of
 > the debug info, but NOT the .debug_line section. .debug_line is
 > quite compact compared to the rest of the debug info: it adds less
 > than 1MB to libgcj.so. Is this extra size worth it to always have
 > stack trace line numbers?
 > 
 > We would want to make sure that we have a fast line number lookup
 > before doing that, though. Currently, line number lookups have a
 > big negative performance impact on certain applications that log
 > stack traces frequently.

Right indeed.  If we have a line number lookup of our own, and if it's
fast enough, it can just look in the debuginfo files.

Andrew.