Binary Compatibility: debug info for compiled Java programs

Wed Jun 9 13:09:00 GMT 2004

On Wed, Jun 09, 2004 at 01:13:49PM +0100, Andrew Haley wrote:
> At the gcc summit last week, we were asked about how we're going to do
> debug info for programs compiled with the BC ABI. This is a problem:
> as we don't know the layout of objects at compile time, we can't
> generate the usual DWARF debugging type info.
>> I said that there were two front-running solutions: calling into
> libgcj runtime routines that access the metadata, or generating DWARF
> debugging type info at run time. Andrew Cagney objects to calling
> libgcj runtime routines, because then we won't be able to debug core
> files. Also, if the runtime library is hosed for some reason, we
> won't be able to debug any structures. This is a good point, and I
> suppose it more or less kills the idea.
>> Bryce pointed out that there is another solution that he favours,
> which involves gdb reading libgcj's metadata.

I'm not familiar with the BC ABI (and missed the talk); could you give
me an example of what information you have at compile time and what you
generate at runtime?
I suspect that a fourth solution is possible: gcj generating DWARF
which describes how to read the metadata. It may not be very
efficient, though, and it will still require a certain amount of
playing with GDB.
-- 
Daniel Jacobowitz