Binary Compatibility: debug info for compiled Java programs

Daniel Jacobowitz drow@false.org
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



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